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Agaronnik ND, Giberson-Chen C, Bono CM. Using advanced imaging to measure bone density, compression fracture risk, and risk for construct failure after spine surgery. Spine J 2024; 24:1135-1152. [PMID: 38437918 DOI: 10.1016/j.spinee.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 01/22/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024]
Abstract
Low bone mineral density (BMD) can predispose to vertebral body compression fractures and postoperative instrumentation failure. DEXA is considered the gold standard for measurement of BMD, however it is not obtained for all spine surgery patients preoperatively. There is a growing body of evidence suggesting that more routinely acquired spine imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) can be opportunistically used to measure BMD. Here we review available studies that assess the validity of opportunistic screening with CT-derived Hounsfield Units (HU) and MRI-derived vertebral vone quality (VBQ) to measure BMD of the spine as well the utility of these measures in predicting postoperative outcomes. Additionally, we provide screening thresholds based on HU and VBQ for prediction of osteopenia/ osteoporosis and postoperative outcomes such as cage subsidence, screw loosening, proximal junctional kyphosis, and implant failure.
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Affiliation(s)
| | - Carew Giberson-Chen
- Harvard Combined Orthopaedic Residency Program, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114
| | - Christopher M Bono
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115; Harvard Combined Orthopaedic Residency Program, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114; Department of Orthopaedic Surgery, Massachusetts General Hospital, 55 Fruit Street, Yawkey Building, Suite 3A, Boston, MA 02114.
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2
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Kumar RP, Adida S, Lavadi RS, Mitha R, Legarreta AD, Hudson JS, Shah M, Diebo B, Fields DP, Buell TJ, Hamilton DK, Daniels AH, Agarwal N. A guide to selecting upper thoracic versus lower thoracic uppermost instrumented vertebra in adult spinal deformity correction. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2024; 33:2742-2750. [PMID: 38522054 DOI: 10.1007/s00586-024-08206-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/26/2024] [Accepted: 02/24/2024] [Indexed: 03/25/2024]
Abstract
PURPOSE Operative treatment of adult spinal deformity (ASD) has been shown to improve patient health-related quality of life (HRQOL). Selection of the uppermost instrumented vertebra (UIV) in either the upper thoracic (UT) or lower thoracic (LT) spine is a pivotal decision with effects on operative and postoperative outcomes. This review overviews the multifaceted decision-making process for UIV selection in ASD correction. METHODS PubMed was queried for articles using the keywords "uppermost instrumented vertebra", "upper thoracic", "lower thoracic", and "adult spinal deformity". RESULTS Optimization of UIV selection may lead to superior deformity correction, better patient-reported outcomes, and lower risk of proximal junctional kyphosis (PJK) and failure (PJF). Patient alignment characteristics, including preoperative thoracic kyphosis, coronal deformity, and the magnitude of sagittal correction influence surgical decision-making when selecting a UIV, while comorbidities such as poor body mass index, osteoporosis, and neuromuscular pathology should also be taken in to account. Additionally, surgeon experience and resources available to the hospital may also play a role in this decision. Currently, it is incompletely understood whether postoperative HRQOLs, functional and radiographic outcomes, and complications after surgery differ between selection of the UIV in either the UT or LT spine. CONCLUSION The correct selection of the UIV in surgical planning is a challenging task, which requires attention to preoperative alignment, patient comorbidities, clinical characteristics, available resources, and surgeon-specific factors such as experience.
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Affiliation(s)
- Rohit Prem Kumar
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Samuel Adida
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Raj Swaroop Lavadi
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rida Mitha
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Andrew D Legarreta
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Joseph S Hudson
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Manan Shah
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Bassel Diebo
- Department of Orthopaedic Surgery, Warren Alpert School of Medicine, Brown University, Providence, RI, USA
| | - Daryl P Fields
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Thomas J Buell
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - D Kojo Hamilton
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Alan H Daniels
- Department of Orthopaedic Surgery, Warren Alpert School of Medicine, Brown University, Providence, RI, USA
| | - Nitin Agarwal
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- Neurological Surgery, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA.
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Tsuchiya K, Okano I, Dodo Y, Hayakawa C, Yamamura R, Maruyama H, Yasukawa T, Shirahata T, Kudo Y. Postoperative decrease in Hounsfield unit values at adjacent vertebrae after thoraco-pelvic fusion as a risk factor of proximal junctional kyphosis. J Orthop Res 2024. [PMID: 38924116 DOI: 10.1002/jor.25924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/16/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
Proximal junctional kyphosis and failure is a common complication of adult spinal deformity surgery, with osteoporosis as a risk factor. This retrospective study investigated the influence of long thoracolumbar fusion with pelvic fixation on regional bone density of adjacent vertebrae (Hounsfield units on computed tomography) and evaluated the association between bone loss and the incidence of proximal junctional kyphosis and failure. Patients who underwent long thoracolumbar fusion (pelvis to T10 or above) or single-level posterior lumbar interbody fusion (control group) between 2016 and 2022 were recruited. Routine computed tomography preoperatively and within 1-2 weeks postoperatively was performed. Postoperative changes in Hounsfield unit values in the vertebrae at one and two levels above the uppermost instrumented vertebrae (UIV + 1 and UIV + 2) were evaluated. Overall, 127 patients were recruited: 45 long fusion (age, 73.9 ± 5.6 years) and 82 proximal junctional kyphosis and failure (age, 72.5 ± 9.3 years). Postoperative computed tomography was performed at a median [interquartile range] of 3.0 [1.0-7.0] and 4.0 [1.0-7.0] days, respectively. In both groups, Hounsfield unit values at UIV + 2 were significantly decreased postoperatively. In the long-fusion group, Hounsfield unit values at UIV + 1 and UIV + 2 were significantly lower in patients with proximal junctional kyphosis and failure (within 18 months postoperatively) than in those without proximal junctional kyphosis and failure. Proximal junctional kyphosis and failure and long thoraco-pelvic fusion negatively affect regional Hounsfield unit values at adjacent levels immediately after surgery. Patients with subsequent proximal junctional kyphosis and failure show greater postoperative bone loss at adjacent levels than those without.
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Affiliation(s)
- Koki Tsuchiya
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Ichiro Okano
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Yusuke Dodo
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Chikara Hayakawa
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Ryo Yamamura
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Hiroshi Maruyama
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
| | - Taiki Yasukawa
- Department of Orthopaedic Surgery, Showa University Koto Toyosu Hospital, Koto, Japan
| | - Toshiyuki Shirahata
- Department of Orthopaedic Surgery, Showa University Koto Toyosu Hospital, Koto, Japan
| | - Yoshifumi Kudo
- Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa, Japan
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Filley A, Baldwin A, Ben-Natan AR, Hansen K, Arora A, Xiao A, Hammond D, Chen C, Tweedt I, Rohde J, Link T, Berven S, Sawyer A. The influence of osteoporosis on mechanical complications in lumbar fusion surgery: a systematic review. NORTH AMERICAN SPINE SOCIETY JOURNAL 2024; 18:100327. [PMID: 38962714 PMCID: PMC11219986 DOI: 10.1016/j.xnsj.2024.100327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 07/05/2024]
Abstract
Background Adults undergoing spine surgery often have underlying osteoporosis, which may be a risk factor for postoperative complications. Although these associations have been described, osteoporosis remains profoundly underdiagnosed and undertreated in the spine surgery population. A thorough, comprehensive systematic review summarizing the relationships between bone mineral density (BMD) and specific complications of lumbar fusion surgery could be a valuable resource for raising awareness and supporting clinical practice changes. Methods PubMed, Embase, and Web of Science databases were searched for original clinical research articles reporting on BMD, or surrogate measure, as a predictor of complications in adults undergoing elective lumbar fusion for degenerative disease or deformity. Endpoints included cage subsidence, screw loosening, pseudarthrosis, vertebral fracture, junctional complications, and reoperation. Results A total of 71 studies comprising 12,278 patients were included. Overall, considerable heterogeneity in study populations, methods of bone health assessment, and definition and evaluation of clinical endpoints precluded meta-analysis. Nevertheless, low BMD was associated with higher rates of implant failures like cage subsidence and screw loosening, which were often diagnosed with concomitant pseudarthrosis. Osteoporosis was also a significant risk factor for proximal junctional kyphosis, particularly due to fracture. Many studies found surgical site-specific BMD to best predict focal complications. Functional outcomes were inconsistently addressed. Conclusions Our findings suggest osteoporosis is a significant risk factor for mechanical complications of lumbar fusion. These results emphasize the importance of preoperative osteoporosis screening, which allows for medical and surgical optimization of high-risk patients. This review also highlights current practical challenges facing bone health evaluation in patients undergoing elective surgery. Future prospective studies using standardized methods are necessary to strengthen existing evidence, identify optimal predictive thresholds, and establish specialty-specific practice guidelines. In the meantime, an awareness of the surgical implications of osteoporosis and utility of preoperative screening can provide for more informed, effective patient care.
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Affiliation(s)
- Anna Filley
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Avionna Baldwin
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Alma Rechav Ben-Natan
- Department of Neurological Surgery, University of California, San Francisco, CA, USA
| | - Keith Hansen
- Department of General Surgery, University of California, San Francisco, CA, USA
| | - Ayush Arora
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Angel Xiao
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Deana Hammond
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Caressa Chen
- Loyola University Medical Center; Maywood IL, USA
| | - Isobel Tweedt
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
- Western University of Health Sciences College of Osteopathic Medicine of the Pacific, USA
| | - James Rohde
- Department of Integrative Biology, University of California Berkeley, USA
| | - Thomas Link
- Department of Radiology and Biomedical Imagery, University of California, San Francisco, CA, USA
| | - Sigurd Berven
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
| | - Aenor Sawyer
- Department of Orthopaedic Surgery, University of California, 435 Warren Drive, Apt 11, San Francisco, CA, USA
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Pennington Z, Mikula AL, Lakomkin N, Martini M, Pinter ZW, Shafi M, Hamouda A, Bydon M, Clarke MJ, Freedman BA, Krauss WE, Nassr AN, Sebastian AS, Fogelson JL, Elder BD. Bone Quality as Measured by Hounsfield Units More Accurately Predicts Proximal Junctional Kyphosis than Vertebral Bone Quality Following Long-Segment Thoracolumbar Fusion. World Neurosurg 2024; 186:e584-e592. [PMID: 38588791 DOI: 10.1016/j.wneu.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/31/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024]
Abstract
OBJECTIVE To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6). METHODS Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK. RESULTS Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106). CONCLUSIONS In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.
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Affiliation(s)
- Zach Pennington
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
| | - Anthony L Mikula
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Nikita Lakomkin
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Michael Martini
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Zachariah W Pinter
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Mahnoor Shafi
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Mohamad Bydon
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Michelle J Clarke
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Brett A Freedman
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - William E Krauss
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Ahmad N Nassr
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Arjun S Sebastian
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Jeremy L Fogelson
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Benjamin D Elder
- Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA
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Tani Y, Naka N, Ono N, Kawashima K, Paku M, Ishihara M, Adachi T, Ando M, Taniguchi S, Saito T. Can We Rely on Prophylactic Two-Level Vertebral Cement Augmentation in Long-Segment Adult Spinal Deformity Surgery to Reduce the Incidence of Proximal Junctional Complications? MEDICINA (KAUNAS, LITHUANIA) 2024; 60:860. [PMID: 38929477 PMCID: PMC11205771 DOI: 10.3390/medicina60060860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/13/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024]
Abstract
Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results-a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)-could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Takanori Saito
- Department of Orthopaedic Surgery, Kansai Medical University, 2-5-1 Shinmachi, Hirakata-City 573-1010, Japan; (Y.T.); (N.N.); (N.O.); (K.K.); (M.P.); (M.I.); (T.A.); (M.A.); (S.T.)
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7
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Striano BM, Crawford AM, Lightsey HM, Ukogu C, Acosta Julbe JI, Gabriel DC, Schoenfeld AJ, Simpson AK. Do Hounsfield Units From Intraoperative CT Scans Correlate With Preoperative Values? Clin Orthop Relat Res 2024:00003086-990000000-01612. [PMID: 38728612 DOI: 10.1097/corr.0000000000003122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/19/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND There is increasing interest in forecasting postoperative complications using bone density metrics. Vertebral Hounsfield unit measurements obtained from CT scans performed for surgical planning or other purposes, known as opportunistic CTs, have shown promise for their ease of measurement and the ability to target density measurement to a particular region of interest. Concomitant with the rising interest in prognostic bone density measurement use has been the increasing adoption of intraoperative advanced imaging techniques. Despite the interest in both outcome prognostication and intraoperative advanced imaging, there is little information regarding the use of CT-based intraoperative imaging as a means to measure bone density. QUESTIONS/PURPOSES (1) Can vertebral Hounsfield units be reliably measured by physician reviewers from CT scans obtained intraoperatively? (2) Do Hounsfield units measured from intraoperative studies correlate with values measured from preoperative CT scans? METHODS To be eligible for this retrospective study, patients had to have been treated with the use of an intraoperative CT scan for instrumented spinal fusion for either degenerative conditions or traumatic injuries between January 2015 and December 2022. Importantly, patients without a preoperative CT scan of the fused levels within 180 days before surgery or who were indicated for surgery because of infection, metastatic disease, or who were having revision surgery after prior instrumentation were excluded from the query. Of the 285 patients meeting these inclusion criteria, 53% (151) were initially excluded for the following reasons: 36% (102) had intraoperative CT scans obtained after placement of instrumentation, 16% (47) had undergone intraoperative CT scans but the studies were not accessible for Hounsfield unit measurement, and 0.7% (2) had prior kyphoplasty wherein the cement prevented Hounsfield unit measurement. Finally, an additional 19% (53) of patients were excluded because the preoperative CT and intraoperative CT were obtained at different peak voltages, which can influence Hounsfield unit measurement. This yielded a final population of 81 patients from whom 276 preoperative and 276 intraoperative vertebral Hounsfield unit measurements were taken. Hounsfield unit data were abstracted from the same vertebra(e) from both preoperative and intraoperative studies by two physician reviewers (one PGY3 and one PGY5 orthopaedic surgery resident, both pursuing spine surgery fellowships). For a small, representative subset of patients, measurements were taken by both reviewers. The feasibility and reliability of Hounsfield unit measurement were then assessed with interrater reliability of values measured from the same vertebra by the two different reviewers. To compare Hounsfield unit values from intraoperative CT scans with preoperative CT studies, an intraclass correlation using a two-way random effects, absolute agreement testing technique was employed. Because the data were formatted as multiple measurements from the same vertebra at different times, a repeated measures correlation was used to assess the relationship between preoperative and intraoperative Hounsfield unit values. Finally, a linear mixed model with patients handled as a random effect was used to control for different patient and clinical factors (age, BMI, use of bone density modifying agents, American Society of Anesthesiologists [ASA] classification, smoking status, and total Charlson comorbidity index [CCI] score). RESULTS We found that Hounsfield units can be reliably measured from intraoperative CT scans by human raters with good concordance. Hounsfield unit measurements of 31 vertebrae from a representative sample of 10 patients, measured by both reviewers, demonstrated a correlation value of 0.82 (95% CI 0.66 to 0.91), indicating good correlation. With regard to the relationship between preoperative and intraoperative measurements of the same vertebra, repeated measures correlation testing demonstrated no correlation between preoperative and intraoperative measurements (r = 0.01 [95% CI -0.13 to 0.15]; p = 0.84). When controlling for patient and clinical factors, we continued to observe no relationship between preoperative and intraoperative Hounsfield unit measurements. CONCLUSION As intraoperative CT and measurement of vertebral Hounsfield units both become increasingly popular, it would be a natural extension for spine surgeons to try to extract Hounsfield unit data from intraoperative CTs. However, we found that although it is feasible to measure Hounsfield data from intraoperative CT scans, the obtained values do not have any predictable relationship with values obtained from preoperative studies, and thus, these values should not be used interchangeably. With this knowledge, future studies should explore the prognostic value of intraoperative Hounsfield unit measurements as a distinct entity from preoperative measurements. LEVEL OF EVIDENCE Level III, diagnostic study.
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Affiliation(s)
- Brendan M Striano
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA, USA
| | - Alexander M Crawford
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA, USA
| | - Harry M Lightsey
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA, USA
| | - Chierika Ukogu
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA, USA
| | - Jose I Acosta Julbe
- Orthopaedic and Arthritis Center for Outcomes Research, Brigham and Women's Hospital, Boston, MA, USA
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Andrew J Schoenfeld
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Andrew K Simpson
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Murata K, Otsuki B, Shimizu T, Sono T, Fujibayashi S, Matsuda S. Sagittal Section Hounsfield Units of the Upper Instrumented Vertebrae as a Predictor of Proximal Junctional Vertebral Fractures Following Adult Spinal Deformity Surgery. Asian Spine J 2024; 18:209-217. [PMID: 38650092 PMCID: PMC11065512 DOI: 10.31616/asj.2023.0339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/13/2023] [Accepted: 12/21/2023] [Indexed: 04/25/2024] Open
Abstract
STUDY DESIGN A retrospective observational study. PURPOSE This study aimed to determine an accurate and convenient screening method for predicting proximal junctional fractures (PJFr) following surgery for adult spinal deformity (ASD) using computed tomography (CT)-based measurement of Hounsfield units (HUs). OVERVIEW OF LITERATURE CT-based measurement of HUs is an alternative tool for assessing bone mineral density. However, the optimal method for predicting adjacent vertebral fractures following spinal fusion using HUs remains unclear. METHODS This retrospective observational study included 42 patients who underwent reconstructive surgery for ASD. Elliptical regions of interest (ROIs) on the axial section and rectangular ROIs on the sagittal section were placed at the upper instrumented vertebrae (UIV), UIV+1, and UIV+2. In addition, the HU value of the L2 vertebra was used as the representative. RESULTS PJFr occurred in 28.6% of patients within 2 years following surgery. The HU values obtained from the axial sections of L2, UIV, UIV+1, and UIV+2 were not significantly associated with the incidence of PJFr within 2 years, except for the ROI set in the lower region of the L2 vertebra. However, the HU value of the anterior third of the UIV in the sagittal section was significantly lower in the PJFr group than in the nonPJFr group (87.0 vs. 160.3, p =0.001). A UIV HU value of <100 was associated with a higher incidence of PJFr than an HU vaue of >100 (p <0.05). CONCLUSIONS Measurements of HU in the anterior one-third of the UIV in the sagittal section demonstrated predictive ability for PJFr following ASD surgery. A UIV HU value of <100 emerged as a risk factor for PJFr.
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Affiliation(s)
- Koichi Murata
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
| | - Bungo Otsuki
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
| | - Takayoshi Shimizu
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
| | - Takashi Sono
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
| | - Shunsuke Fujibayashi
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
- Department of Orthopaedic Surgery, Kijunkai Yoshikawa Hospital, Kyoto,
Japan
| | - Shuichi Matsuda
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Kyoto,
Japan
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9
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Crawford AM, Striano BM, Amakiri IC, Williams DL, Lindsey MH, Gong J, Simpson AK, Schoenfeld AJ. The utility of vertebral Hounsfield units as a prognostic indicator of adverse events following treatment of spinal epidural abscess. NORTH AMERICAN SPINE SOCIETY JOURNAL 2024; 17:100308. [PMID: 38264152 PMCID: PMC10803939 DOI: 10.1016/j.xnsj.2024.100308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/25/2024]
Abstract
Background Spinal epidural abscesses (SEAs) are a devastating condition with high levels of associated morbidity and mortality. Hounsfield units (HUs), a marker of radiodensity on CT scans, have previously been correlated with adverse events following spinal interventions. We evaluated whether HUs might also be associated with all-cause complications and/or mortality in this high-risk population. Methods This retrospective cohort study was carried out within an academic health system in the United States. Adults diagnosed with a SEA between 2006 and 2021 and who also had a CT scan characterizing their SEA within 6 months of diagnosis were considered. HUs were abstracted from the 4 vertebral bodies nearest to, but not including, the infected levels. Our primary outcome was the presence of composite 90-day complications and HUs represented the primary predictor. A multivariable logistic regression analysis was conducted adjusting for demographic and disease-specific confounders. In sensitivity testing, separate logistic regression analyses were conducted (1) in patients aged 65 and older and (2) with mortality as the primary outcome. Results Our cohort consisted of 399 patients. The overall incidence of 90-day complications was 61.2% (n=244), with a 7.8% (n=31) 90-day mortality rate. Those experiencing complications were more likely to have undergone surgery to treat their SEA (58.6% vs. 46.5%; p=.018) but otherwise the cohorts were similar. HUs were not associated with composite 90-day complications (Odds ratio [OR] 1.00 [95% CI 1.00-1.00]; p=.842). Similar findings were noted in sensitivity testing. Conclusions While HUs have previously been correlated with adverse events in certain clinical contexts, we found no evidence to suggest that HUs are associated with all-cause complications or mortality in patients with SEAs. Future research hoping to leverage 3-dimensional imaging as a prognostic measure in this patient population should focus on alternative targets. Level of Evidence Level III; Observational Cohort study.
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Affiliation(s)
- Alexander M. Crawford
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA 02115,United States
| | - Brendan M. Striano
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA 02115,United States
| | - Ikechukwu C. Amakiri
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA 02115,United States
| | | | - Matthew H. Lindsey
- Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA 02115,United States
| | - Jonathan Gong
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115,United States
| | - Andrew K. Simpson
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115,United States
| | - Andrew J. Schoenfeld
- Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115,United States
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10
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Lovecchio F, Ang B, Louie PK, Chaudary C, Shah SP, Punyala A, Yao YC, Steinhaus M, McCarthy MH, Huang R, Lebl D, Lafage V, Albert TJ, Iyer S, Qureshi S, Kim HJ. Bone Density Distribution in the Cervical Spine. Global Spine J 2024; 14:169-176. [PMID: 35485915 PMCID: PMC10676188 DOI: 10.1177/21925682221098965] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
STUDY DESIGN Retrospective cohort study. OBJECTIVE Given changes in bone density induced by degenerative disease, general measures of bone health (ie DEXA) are inadequate to evaluate bone density in surgical areas of interest. Regional differences in HU in the cervical spine may influence surgical strategies. The purposes of our study were to determine whether cervical Hounsfield units (HU) vary by level, examine their relationship with age, comorbidities, and alignment, and propose a technique to measure HU in the lateral masses. METHODS Two hundred twenty-four patients with degenerative spine pathology with a cervical computed tomography were included (2015-2019). Measurements were performed in each vertebral body (C2-T1; mid-axial, anterior-axial, posterior-axial, mid-coronal, and mid-sagittal) and 2 regions of the lateral masses (C3-C6; mid-cor, mid-sag). To evaluate reliability, 6 observers each measured 355 HU values, inter-relater reliability assessed with intraclass correlation coefficients Correlations of HU with age, BMI, comorbidities, and cervical alignment were evaluated. RESULTS Bone density differed by level, with the lowest HU scores in the lower cervical spine (C6-T1) (P < .001). No correlations were found between LM HU and age, BMI, CCI, or alignment (P > .05). Increased kyphosis was weakly correlated with VB HU, while age and CCI showed moderate correlations with VB HU at all levels (P<.001). ICC for HU measurements were good to excellent for the VBs, but poor to moderate for the LMs. CONCLUSION Bone is least dense in the lower cervical spine. HU scoring is not reliable in the lateral masses. We recommend that a level-specific approach to bone density is considered in surgical planning.
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Affiliation(s)
- Francis Lovecchio
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Bryan Ang
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Philip K. Louie
- Department of Neurosurgery, Center for Neurosciences and Spine, Virginia Mason Franciscan Health, Seattle, WA, USA
| | - Chirag Chaudary
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Sachin P. Shah
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Ananth Punyala
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Yu-Cheng Yao
- Department of Orthopedics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Mike Steinhaus
- Spine Institute, MountainStar Healthcare, Park City, UT, USA
| | - Michael H. McCarthy
- Department of Orthopaedic Surgery, Indiana Spine Group, University of Indiana, Carmel, ID, USA
| | - Russel Huang
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Darren Lebl
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Virginie Lafage
- Department of Orthopaedic Surgery, Lenox Hill Hospital, New York, NY, USA
| | - Todd J. Albert
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Sravisht Iyer
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Sheeraz Qureshi
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
| | - Han Jo Kim
- Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY, USA
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11
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Johnson GW, Chanbour H, Ali MA, Chen J, Metcalf T, Doss D, Younus I, Jonzzon S, Roth SG, Abtahi AM, Stephens BF, Zuckerman SL. Artificial Intelligence to Preoperatively Predict Proximal Junction Kyphosis Following Adult Spinal Deformity Surgery: Soft Tissue Imaging May Be Necessary for Accurate Models. Spine (Phila Pa 1976) 2023; 48:1688-1695. [PMID: 37644737 PMCID: PMC11101214 DOI: 10.1097/brs.0000000000004816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
STUDY DESIGN Retrospective cohort. OBJECTIVE In a cohort of patients undergoing adult spinal deformity (ASD) surgery, we used artificial intelligence to compare three models of preoperatively predicting radiographic proximal junction kyphosis (PJK) using: (1) traditional demographics and radiographic measurements, (2) raw preoperative scoliosis radiographs, and (3) raw preoperative thoracic magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA Despite many proposed risk factors, PJK following ASD surgery remains difficult to predict. MATERIALS AND METHODS A single-institution, retrospective cohort study was undertaken for patients undergoing ASD surgery from 2009 to 2021. PJK was defined as a sagittal Cobb angle of upper-instrumented vertebra (UIV) and UIV+2>10° and a postoperative change in UIV/UIV+2>10°. For model 1, a support vector machine was used to predict PJK within 2 years postoperatively using clinical and traditional sagittal/coronal radiographic variables and intended levels of instrumentation. Next, for model 2, a convolutional neural network (CNN) was trained on raw preoperative lateral and posterior-anterior scoliosis radiographs. Finally, for model 3, a CNN was trained on raw preoperative thoracic T1 MRIs. RESULTS A total of 191 patients underwent ASD surgery with at least 2-year follow-up and 89 (46.6%) developed radiographic PJK within 2 years. Model 1: Using clinical variables and traditional radiographic measurements, the model achieved a sensitivity: 57.2% and a specificity: 56.3%. Model 2: a CNN with raw scoliosis x-rays predicted PJK with a sensitivity: 68.2% and specificity: 58.3%. Model 3: a CNN with raw thoracic MRIs predicted PJK with average sensitivity: 73.1% and specificity: 79.5%. Finally, an attention map outlined the imaging features used by model 3 elucidated that soft tissue features predominated all true positive PJK predictions. CONCLUSIONS The use of raw MRIs in an artificial intelligence model improved the accuracy of PJK prediction compared with raw scoliosis radiographs and traditional clinical/radiographic measurements. The improved predictive accuracy using MRI may indicate that PJK is best predicted by soft tissue degeneration and muscle atrophy.
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Affiliation(s)
| | - Hani Chanbour
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Mir Amaan Ali
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Chen
- Vanderbilt University School of Medicine, Nashville, TN
| | - Tyler Metcalf
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Derek Doss
- Vanderbilt University School of Medicine, Nashville, TN
| | - Iyan Younus
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Soren Jonzzon
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Steven G. Roth
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Amir M. Abtahi
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Byron F. Stephens
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Scott L. Zuckerman
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
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12
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Chanbour H, Chen JW, Vaughan WE, Abtahi AM, Gardocki RJ, Stephens BF, Zuckerman SL. Which Bone Mineral Density Measure Offers a More Reliable Prediction of Mechanical Complications in Adult Spinal Deformity Surgery: Hounsfield Units or DEXA Scan? World Neurosurg 2023; 178:e657-e665. [PMID: 37543204 DOI: 10.1016/j.wneu.2023.07.140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/07/2023]
Abstract
OBJECTIVE In patients undergoing adult spinal deformity (ASD) surgery, we sought to: (1) determine the relationship between dual-energy x-ray absorptiometry (DEXA)-measured bone mineral density (BMD), T-scores, and Hounsfield units (HU), and (2) compare the ability of DEXA-measured BMD, T-scores, and HU to predict mechanical complications and reoperations. METHODS A single-institution retrospective cohort study was undertaken for cases from 2013 to 2017. INCLUSION CRITERIA ≥5-level-fusion, sagittal/coronal deformity, and 2-year follow-up. Multivariable regression controlled for age, body mass index, receiving anabolic medications, and postoperative sagittal vertical axis and pelvic-incidence lumbar-lordosis mismatch. A subanalysis was performed for osteopenic patients (-1 < T-score < -2). RESULTS Of 145 patients undergoing ASD surgery, 72 (49.6%) had both preoperative DEXA and computed tomography scans. Mean DEXA-measured BMD was 0.91 ± 0.52 g/cm2, mean T-score was -1.61 ± 1.03, and mean HU was 153.5 ± 52.8. While no correlation was found between DEXA-measured BMD and HU (r = 0.17, P = 0.144), T-score and HU had a weakly positive correlation (r = 0.31, P = 0.007). Mechanical complications occurred in 48 (66.7%) patients, including 27 (37.5%) proximal junctional kyphosis (PJK), 1 (1.4%) distal junctional kyphosis, 5 (6.9%) implant failure, 30 (41.7%) rod fracture/pseudarthrosis, 42 (58.3%) reoperations, and 16 (22.2%) reoperations due to PJK. No association was found between DEXA-measured BMD or T-scores with mechanical complications or reoperations. While univariate regression showed a significant association between lower HU and PJK (OR 0.98, 95%CI 0.97-0.99, P = 0.011), the significance was lost after multivariable analysis. When considering osteopenic patients (n = 37), only DEXA-measured BMD was an independent risk factor for PJK (OR 0.01, 95%CI 0.00-0.09, P = 0.017), with a threshold of 0.82 g/cm2 (AUC 0.70, 95%CI 0.53-0.84, P = 0.019). CONCLUSIONS Poor correlation was found between the 3 BMD modalities. DEXA-measured BMD may be superior to T-scores and HU in predicting PJK among patients with osteopenia with a threshold of BMD <0.82 g/cm2.
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Affiliation(s)
- Hani Chanbour
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jeffrey W Chen
- School of Medicine, Vanderbilt University, Nashville, Tennessee, USA
| | - Wilson E Vaughan
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Amir M Abtahi
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Raymond J Gardocki
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Byron F Stephens
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Scott L Zuckerman
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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13
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Tsutsui S, Hashizume H, Iwasaki H, Takami M, Ishimoto Y, Nagata K, Yamada H. Sarcopenia at the upper instrumented vertebra is more significantly associated with proximal junctional kyphosis after long fusion for adult spinal deformity surgery than osteopenia. J Clin Neurosci 2023; 116:13-19. [PMID: 37597329 DOI: 10.1016/j.jocn.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/21/2023]
Abstract
Proximal junctional kyphosis (PJK) is a major mechanical complication after adult spinal deformity (ASD) surgery, and is multifactorial. Osteopenia and sarcopenia are patient risk factors, but it has not yet been well-documented which of them is the more significant risk factor. We retrospectively studied patients older than 50 years who underwent ASD surgery from the lower thoracic spine to the pelvis. In addition to patient demographic data and pre- and post-operative radiographic sagittal parameters (PI: pelvic incidence; LL: lumbar lordosis; SVA: sagittal vertical axis; PT: pelvic tilt), Hounsfield unit (HU) values on preoperative computed tomography and cross sectional area (CSA) and fatty infiltration ratio (FI%) of the paraspinal musculature (PSM) on preoperative magnetic resonance image were measured from the upper-instrumented vertebra (UIV) to UIV + 2 and averaged. PJK was observed in 11 of 29 patients. There was no statistical difference between the patients with and without PJK in age at surgery, sex, body mass index, bone mineral density, preoperative PI-LL, SVA, PT, postoperative PI-LL, SVA, PT, HU, and CSA. FI% in patients with PJK (25.0) was significantly higher than that (15.3) in patients without PJK (P = 0.001). Logistic regression analysis identified FI% of PSM as a significant independent factor of PJK (odds ratio, 1.973; 95% confidence interval, 1.290-5.554; P < 0.0001). After successful elimination of possible factors related to PJK other than sarcopenia and osteopenia, sarcopenia assessed by fatty degeneration of the PSM at the UIV was shown to be a more important factor than osteopenia for PJK after long fusion for ASD.
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Affiliation(s)
- Shunji Tsutsui
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan.
| | - Hiroshi Hashizume
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
| | - Hiroshi Iwasaki
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
| | - Masanari Takami
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
| | - Yuyu Ishimoto
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
| | - Keiji Nagata
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
| | - Hiroshi Yamada
- Department of Orthopedic Surgery, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan
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14
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Yagi M, Yamanouchi K, Fujita N, Funao H, Ebata S. Proximal Junctional Failure in Adult Spinal Deformity Surgery: An In-depth Review. Neurospine 2023; 20:876-889. [PMID: 37798983 PMCID: PMC10562237 DOI: 10.14245/ns.2346566.283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 10/07/2023] Open
Abstract
Adult spinal deformity (ASD) surgery aims to correct abnormal spinal curvature in adults, leading to improved functionality and reduced pain. However, this surgery is associated with various complications, one of which is proximal junctional failure (PJF). PJF can have a significant impact on a patient's quality of life, necessitating a comprehensive understanding of its causes and the development of effective management strategies. This review aims to provide an in-depth understanding of PJF in ASD surgery. PJF is a complex complication resulting from a multitude of factors including patient characteristics, surgical techniques, and postoperative management. Age, osteoporosis, overcorrection of sagittal alignment, and poor bone quality are identified as significant risk factors. The clinical implications of PJF are substantial, often requiring revision surgery and causing a considerable decrease in patients' quality of life. Prevention strategies include careful preoperative planning, appropriate patient selection, and optimization of surgical techniques. Treatment often necessitates a multifaceted approach, including surgical intervention and the management of underlying risk factors. Predictive modeling is an emerging field that may offer a promising avenue for the risk stratification of patients and individualized preventive strategies. A thorough understanding of PJF's pathogenesis, risk factors, and clinical implications is essential for surgeons involved in ASD surgery. Current preventive measures and treatment strategies aim to mitigate the risk and manage the complications of PJF, but the complication cannot be entirely prevented. Future research should focus on the development of more effective preventive and treatment strategies, and predictive models could be valuable in this pursuit.
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Affiliation(s)
- Mitsuru Yagi
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Kento Yamanouchi
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Naruhito Fujita
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Haruki Funao
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Shigeto Ebata
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
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Maruo K, Arizumi F, Kishima K, Yoshie N, Kusukawa T, Tachibana T. Effects of Perioperative Teriparatide Treatment on the Hounsfield Unit Values at the Upper Instrumented Vertebra in Adult Spinal Deformity Surgery. Clin Spine Surg 2023; 36:E234-E238. [PMID: 36788439 DOI: 10.1097/bsd.0000000000001434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 12/13/2022] [Indexed: 02/16/2023]
Abstract
STUDY DESIGN Retrospective single-center study. OBJECTIVE This study aimed to assess the effects of pre and postoperative teriparatide (TPTD) treatment on Hounsfield units (HU) after surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA The most commonly used method for assessing bone mineral density is dual-energy x-ray absorptiometry. HU values at the upper instrumented vertebra (UIV) have been proposed as a surrogate method for assessing bone quality, particularly in patients with ASD. However, the effect of TPTD treatment on vertebral HU values remains unclear. MATERIALS AND METHODS We identified 57 consecutive patients with ASD who underwent long-instrumented fusion surgery (>5 vertebrae) between 2014 and 2020. Patients were retrospectively divided into a non-TPTD group (n = 31) and a TPTD group (n = 26). HU measurements were obtained at a level above the UIV (UIV + 1). Changes in the HU value at 1-year postoperatively were compared between the TPTD and non-TPTD groups. The duration of preoperative TPTD was compared between the proximal junctional proximal junctional failure (PJF) and non-PJF groups. RESULTS Preoperative HU values were significantly lower in the TPTD group than in the non-TPTD group, despite no significant difference in preoperative bone mineral density of the proximal femur between the two groups. Changes in HU values were significantly higher in the TPTD group than in the non-TPTD group (20.8 ± 15.7% vs -2 ± 10.2%, P < 0.001). In the subanalysis of the TPTD group, the duration of preoperative TPTD treatment was significantly shorter in the PJF group than in the non-PJF group (34.7 ± 16.8 days vs 86.9 ± 34.7 days, P = 0.004). CONCLUSIONS Pre and post-operative TPTD treatment increased the average HU value at UIV + 1 by 20.8%. Therefore, more prolonged preoperative TPTD treatment improves bone quality and may help prevent osteoporosis-related complications.
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Affiliation(s)
- Keishi Maruo
- Department of Orthopedic Surgery, Hyogo College of Medicine, Nishinomiya, Japan
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16
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Yoshie N, Maruo K, Arizumi F, Kishima K, Kusukawa T, Tachibana T. The Relationship between the Hounsfield Units Value of the Upper Instrumented Vertebra and the Severity of Proximal Junctional Fracture after Adult Spinal Deformity Surgery. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1086. [PMID: 37374290 DOI: 10.3390/medicina59061086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/03/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023]
Abstract
Background and Objectives: In this retrospective cohort study, we investigate associations between the Hounsfield units (HU) value of upper instrumented vertebra (UIV) and proximal junctional kyphosis (PJK) after adult spinal deformity (ASD) surgery. Materials and Methods: The cohort consisted of 60 patients (mean age 71.7 years) who underwent long instrumented fusion surgery (≥6 vertebrae) for ASD with at least 1 year of follow-up. The preoperative bone mineral density (BMD) measured on DXA scans, the HU values at UIV and UIV+1, and the radiographic parameters were compared between the PJK and non-PJK groups. The severity of UIV fracture was assessed using a semiquantitative (SQ) grade. Results: PJK occurred in 43% of patients. No significant differences in patient age, sex, BMD, and preoperative radiographic parameters were observed between the PJK and non-PJK groups. The HU values of the UIV (103.4 vs. 149.0, p < 0.001) and UIV+1 (102.0 vs. 145.7, p < 0.001) were significantly lower in the PJK group. The cutoff values of HU at UIV and UIV+1 were 122.8 and 114.9, respectively. Lower HU values at UIV (Grade 1: 134.2, Grade 2: 109.6, Grade 3: 81.1, p < 0.001) and UIV+1 (Grade 1: 131.5, Grade 2: 107.1, Grade 3: 82.1, p < 0.001) were associated with severe SQ grade. Conclusions: Lower HU values at UIV and UIV+1 had a negative impact on signal incidence of PJK and were correlated with the severity of UIV fractures. Preoperative treatment of osteoporosis seems necessary for preoperative UIV HU values less than 120.
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Affiliation(s)
- Norichika Yoshie
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Keishi Maruo
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Fumihiro Arizumi
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Kazuya Kishima
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Tomoyuki Kusukawa
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
| | - Toshiya Tachibana
- Department of Orthopaedic Surgery, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya 663-8501, Japan
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17
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Chen JW, Longo M, Chanbour H, LaBarge ME, Abtahi AM, Stephens BF, Zuckerman SL. Cranially Directed Upper Instrumented Vertebrae Screw Angles Are Associated With Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery. Spine (Phila Pa 1976) 2023; 48:710-719. [PMID: 36728801 DOI: 10.1097/brs.0000000000004573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/10/2022] [Indexed: 02/03/2023]
Abstract
STUDY DESIGN A retrospective cohort study. OBJECTIVE To evaluate the impact of the upper instrumented vertebral (UIV) screw angle in adult spinal deformity (ASD) surgery on: (1) proximal junctional kyphosis/failure (PJK/F), (2) mechanical complications and radiographic measurements, and (3) patient-reported outcome measures (PROMs). SUMMARY OF BACKGROUND DATA The effect of UIV screw angle in ASD surgery on patient outcomes remains understudied. MATERIALS AND METHODS A single-institution, retrospective study was undertaken from 2011 to 2017. UIV screw angle was trichotomized into positive: cranially directed screws relative to the superior endplate (2°≤θ), neutral: parallel to the superior endplate (-2°<θ<2°), and negative: caudally directed screws relative to the superior endplate (-2°≥θ). The primary outcome was PJK/F. Secondary outcomes included remaining mechanical complications, reoperation, and PROMs: Oswestry Disability Index, Numeric Rating Scale (NRS) back/leg, and EuroQol. Regression controlled for age, body mass index, postoperative sagittal vertical axis (SVA), and pelvic incidence lumbar-lordosis mismatch. RESULTS Among 145 patients undergoing ASD surgery, UIV screw angles were 35 (24.1%) cranially directed, 24 (16.6%) neutral, and 86 (59.3%) caudally directed. PJK occurred in 47(32.4%) patients. Positive screws were independently associated with increased PJK [odds ratio (OR)=4.88; 95% CI, 1.85-13.5, P =0.002] and PJF (OR=3.06; 95% CI, 1.32-12.30, P =0.015). Among 108 (74.5%) patients with lower thoracic UIV, PJK occurred in 38 (35.1%). Cranially directed screws were independently associated with an increased odds of PJK (OR=5.56; 95% CI, 1.86-17.90, P =0.003) with a threshold of 0.2° (area under the curve =0.65; 95% CI, 0.54-0.76, P <0.001), above which the risk of PJK significantly increased. No association was found between positive screw angle and PJF (OR=3.13; 95% CI, 0.91-11.40, P =0.073). Because of the low number of patients with an upper thoracic UIV (N=37, 25.5%), no meaningful conclusions could be drawn from this subgroup. There was no association between UIV screw angle and remaining mechanical complications, reoperations, postoperative SVA and T1-pelvic angle, or PROMs. CONCLUSIONS Cranially directed UIV screw angles increased the odds of PJK in patients with lower thoracic UIV. Meticulous attention should be paid to the lower thoracic UIV screw angle to mitigate the risk of PJK in ASD.
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Affiliation(s)
- Jeffrey W Chen
- School of Medicine, Vanderbilt University, Nashville, TN
| | - Michael Longo
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Hani Chanbour
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Matthew E LaBarge
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Amir M Abtahi
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Byron F Stephens
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
| | - Scott L Zuckerman
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, TN
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Keaveny TM, Adams AL, Fischer H, Brara HS, Burch S, Guppy KH, Kopperdahl DL. Increased risks of vertebral fracture and reoperation in primary spinal fusion patients who test positive for osteoporosis by Biomechanical Computed Tomography analysis. Spine J 2023; 23:412-424. [PMID: 36372353 DOI: 10.1016/j.spinee.2022.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND CONTEXT While osteoporosis is a risk factor for adverse outcomes in spinal fusion patients, diagnosing osteoporosis reliably in this population has been challenging due to degenerative changes and spinal deformities. Addressing that challenge, biomechanical computed tomography analysis (BCT) is a CT-based diagnostic test for osteoporosis that measures both bone mineral density and bone strength (using finite element analysis) at the spine; CT scans taken for spinal evaluation or previous care can be repurposed for the analysis. PURPOSE Assess the effectiveness of BCT for preoperatively identifying spinal fusion patients with osteoporosis who are at high risk of reoperation or vertebral fracture. STUDY DESIGN Observational cohort study in a multi-center integrated managed care system using existing data from patient medical records and imaging archives. PATIENT SAMPLE We studied a randomly sampled subset of all adult patients who had any type of primary thoracic (T4 or below) or lumbar fusion between 2005 and 2018. For inclusion, patients with accessible study data needed a preop CT scan without intravenous contrast that contained images (before any instrumentation) of the upper instrumented vertebral level. OUTCOME MEASURES Reoperation for any reason (primary outcome) or a newly documented vertebral fracture (secondary outcome) occurring up to 5 years after the primary surgery. METHODS All study data were extracted using available coded information and CT scans from the medical records. BCT was performed at a centralized lab blinded to the clinical outcomes; patients could test positive for osteoporosis based on either low values of bone strength (vertebral strength ≤ 4,500 N women or 6,500 N men) and/or bone mineral density (vertebral trabecular bone mineral density ≤ 80 mg/cm3 both sexes). Cox proportional hazard ratios were adjusted by age, presence of obesity, and whether the fusion was long (four or more levels fused) or short (3 or fewer levels fused); Kaplan-Meier survival was compared by the log rank test. This project was funded by NIH (R44AR064613) and all physician co-authors and author 1 received salary support from their respective departments. Author 6 is employed by, and author 1 has equity in and consults for, the company that provides the BCT test; the other authors declare no conflicts of interest. RESULTS For the 469 patients analyzed (298 women, 171 men), median follow-up time was 44.4 months, 11.1% had a reoperation (median time 14.5 months), and 7.7% had a vertebral fracture (median time 2.0 months). Overall, 25.8% of patients tested positive for osteoporosis and no patients under age 50 tested positive. Compared to patients without osteoporosis, those testing positive were at almost five-fold higher risk for vertebral fracture (adjusted hazard ratio 4.7, 95% confidence interval = 2.2-9.7; p<.0001 Kaplan-Meier survival). Of those positive-testing patients, those who tested positive concurrently for low values of both bone strength and bone mineral density (12.6% of patients overall) were at almost four-fold higher risk for reoperation (3.7, 1.9-7.2; Kaplan-Meier survival p<.0001); the remaining positive-testing patients (those who tested positive for low values of either bone strength or bone mineral density but not both) were not at significantly higher risk for reoperation (1.6, 0.7-3.7) but were for vertebral fracture (4.3, 1.9-10.2). For both clinical outcomes, risk remained high for patients who underwent short or long fusion. CONCLUSION In a real-world clinical setting, BCT was effective in identifying primary spinal fusion patients aged 50 or older with osteoporosis who were at elevated risks of reoperation and vertebral fracture.
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Affiliation(s)
- Tony M Keaveny
- Departments of Mechanical Engineering and Bioengineering, University of California, Berkeley, CA, USA.
| | - Annette L Adams
- Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA
| | - Heidi Fischer
- Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA
| | - Harsimran S Brara
- Department of Neurosurgery, Southern California Permanente Medical Group, Los Angeles, CA, USA
| | - Shane Burch
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Kern H Guppy
- Department of Neurosurgery, Kaiser Permanente Medical Group, Sacramento, CA, USA
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19
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Camino-Willhuber G, Guiroy A, Servidio M, Astur N, Nin-Vilaró F, Alvarado-Gomez F, Daher M, Saciloto B, Ono A, Letaif O, Zarate-Kalfopulos B, Yurac R, Vialle E, Valacco M. Unplanned Readmission Following Early Postoperative Complications After Fusion Surgery in Adult Spine Deformity: A Multicentric Study. Global Spine J 2023; 13:74-80. [PMID: 33504208 PMCID: PMC9837501 DOI: 10.1177/2192568221991101] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
STUDY DESIGN Multicentric retrospective study, Level of evidence III. OBJECTIVE The objective of this multicentric study was to analyze the prevalence and risk factors of early postoperative complications in adult spinal deformity patients treated with fusion. Additionally, we studied the impact of complications on unplanned readmission and hospital length of stay. METHODS Eight spine centers from 6 countries in Latin America were involved in this study. Patients with adult spinal deformity treated with fusion surgery from 2017 to 2019 were included. Baseline and surgical characteristics such as age, sex, comorbidities, smoking, number of levels fused, number of surgical approaches were analyzed. Postoperative complications at 30 days were recorded according to Clavien-Dindo and Glassman classifications. RESULTS 172 patients (120 females/52 males, mean age 59.4 ± 17.6) were included in our study. 78 patients suffered complications (45%) at 30 days, 43% of these complications were considered major. Unplanned readmission was observed in 35 patients (20,3%). Risk factors for complications were: Smoking, previous comorbidities, number of levels fused, two or more surgical approaches and excessive bleeding. Hospital length of stay in patients without and with complications was of 7.8 ± 13.7 and 17 ± 31.1 days, respectively (P 0.0001). CONCLUSION The prevalence of early postoperative complications in adult spinal deformity patients treated with fusion was of 45% in our study with 20% of unplanned readmissions at 30 days. Presence of complications significantly increased hospital length of stay.
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Affiliation(s)
- Gaston Camino-Willhuber
- Institute of Orthopedics “Carlos E.
Ottolenghi,” Hospital Italiano de Buenos Aires, Buenos Aires, Argentina,AOSpine Latin America Study Group,
Curitiba, Brazil,Gaston Camino-Willhuber, Orthopaedic and
Traumatology Department. Institute of Orthopedics “Carlos E. Ottolenghi,”
Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.
| | - Alfredo Guiroy
- AOSpine Latin America Study Group,
Curitiba, Brazil,Spine Unit, Orthopedic Department,
Hospital Español de Mendoza, Mendoza, Argentina
| | | | - Nelson Astur
- AOSpine Latin America Study Group,
Curitiba, Brazil,Santa Casa de Misericordia de San Pablo,
São Paulo, Brazil,Hospital Israelita Albert Einstein,
Morumbi, São Paulo, Brazil
| | | | | | - Murilo Daher
- Departamento de Ortopedia e
Traumatologia, Faculdade de Medicina, Universidade Federal de Goiás, Goiânia, GO,
Brasil
| | - Bruno Saciloto
- Clínica Bambina Pontifícia
Universidade Católica do Paraná, Brasil
| | - Allan Ono
- Hospital das Clínicas da Faculdade de
Medicina da Universidade de São Paulo (IOT-HCFMUSP), Instituto de Ortopedia e
Traumatología, Spine Surgery Division, São Paulo, SP, Brazil
| | - Olavo Letaif
- Department of Orthopedics and
Traumatology, IOT HCFMUSP, São Paulo, Brazil
| | - Baron Zarate-Kalfopulos
- AOSpine Latin America Study Group,
Curitiba, Brazil,Instituto Nacional de Rehabilitación,
Distrito Federal, Mexico
| | - Ratko Yurac
- AOSpine Latin America Study Group,
Curitiba, Brazil,Department of Orthopedic and
Traumatology, University del Desarrollo, Santiago, Chile,Spine Unit, Department of
Traumatology, Clínica Alemana, Santiago, Chile
| | - Emiliano Vialle
- AOSpine Latin America Study Group,
Curitiba, Brazil,Cajuru Hospital, Catholic University
of Parana, Caritiba, Brazil
| | - Marcelo Valacco
- AOSpine Latin America Study Group,
Curitiba, Brazil,Hospital Churruca Visca, Buenos Aires,
Argentina
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20
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Quarto E, Zanirato A, Pellegrini M, Vaggi S, Vitali F, Bourret S, Le Huec JC, Formica M. GAP score potential in predicting post-operative spinal mechanical complications: a systematic review of the literature. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2022; 31:3286-3295. [PMID: 36153789 DOI: 10.1007/s00586-022-07386-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 07/18/2022] [Accepted: 09/10/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE In 2017, the GAP score was proposed as a tool to reduce mechanical complications (MC) in adult spinal deformity (ASD) surgery: the reported MC rate for the GAP proportioned category was only 6%, which is clearly lower to the MC rate reported in the literature. The aim of this study is to analyse if the most recent literature confirms the promising results of the original article. MATERIALS AND METHODS Using the PRISMA flow chart, we reviewed the literature to analyse GAP score capacity in predicting MC occurrence. We included articles clearly reporting ASD surgery MC stratified by GAP categories and the score's overall capacity to predict MC using the area under the curve (AUC). The quality of the included studies was evaluated using GRADE and MINORS systems. RESULTS Eleven retrospective articles (1,517 patients in total) were included. The MC distribution per GAP category was as follows: GAP-P, 32.8%; GAP-MD, 42.3%; GAP-SD, 55.4%. No statistically significant difference was observed between the different categories using the Kruskal-Wallis test (p = 0.08) and the two-by-two Pearson-Chi square test (P Vs MD, p = 0.300; P Vs SD, p = 0.275; MD Vs SD, p = 0.137). The global AUC was 0.68 ± 0.2 (moderate accuracy). The included studies were of poor quality according to the GRADE system and had a high risk of bias based on the MINORS criteria. CONCLUSION The actual literature does not corroborate the excellent results reported by the original GAP score article. Further prospective studies, possibly stratified by type of MC and type of surgery, are necessary to validate this score.
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Affiliation(s)
- E Quarto
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy.
| | - A Zanirato
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy
| | - M Pellegrini
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy
| | - S Vaggi
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy
| | - F Vitali
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy
| | - S Bourret
- Vertebra, Polyclinique Bordeaux Nord Aquitaine, 15 Rue Boucher, 33300, Bordeaux, France
| | - J C Le Huec
- Vertebra, Polyclinique Bordeaux Nord Aquitaine, 15 Rue Boucher, 33300, Bordeaux, France
| | - M Formica
- Clinica Ortopedica, IRCCS Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genoa, GE, Italy
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21
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Ham DW, Kim HJ, Park SM, Park SJ, Park J, Yeom JS. The importance of thoracolumbar junctional orientation, change in thoracolumbar angle, and overcorrection of lumbar lordosis in development of proximal junctional kyphosis in adult spinal deformity surgery. J Neurosurg Spine 2022; 37:874-882. [PMID: 35901696 DOI: 10.3171/2022.5.spine211528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/10/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Changes in the thoracolumbar angle (TLA) would play a pivotal role in the reciprocal changes following spine realignment surgery, thereby leading to the development of proximal junctional kyphosis (PJK). This study aimed to investigate the association between TLA and the development of PJK following adult spinal deformity surgery. METHODS A total of 107 patients were divided into PJK+ and PJK- groups according to the development of PJK within 12 months after surgery. The TLA and spinopelvic radiological parameters were compared between the PJK+ and PJK- groups. A multivariate logistic regression model was used to identify the risk factors for PJK. The receiver operating characteristic curves of the regression models were used to investigate the cutoff values of significant parameters needed so that PJK would not occur. RESULTS The change in TLA (ΔTLA) in the PJK+ group was significantly larger than in the PJK- group (6.7° ± 7.9° and 2.2° ± 8.1°, respectively; p = 0.006). Multivariate logistic regression analysis demonstrated that age, postoperative pelvic incidence-lumbar lordosis, and ΔTLA were significant risk factors for PJK. The risk of developing PJK was higher when the postoperative pelvic incidence-lumbar lordosis was < 5.2 and the ΔTLA was > 3.58°. CONCLUSIONS The present study highlights the thinking that extensive correction of TLA and lumbar lordosis should be avoided in patients with adult spinal deformity. Overcorrection of TLA of > 3.58° could result in higher odds of PJK.
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Affiliation(s)
- Dae-Woong Ham
- 1Department of Orthopedic Surgery, Chungang University Hospital, Seoul
| | - Ho-Joong Kim
- 2Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam; and
| | - Sang-Min Park
- 2Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam; and
| | - Se Jin Park
- 2Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam; and
| | - Jiwon Park
- 3Department of Orthopedic Surgery, Korea University Ansan Hospital, Gyeonggi-do, South Korea
| | - Jin S Yeom
- 2Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam; and
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22
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Mikula AL, Lakomkin N, Pennington Z, Pinter ZW, Nassr A, Freedman B, Sebastian AS, Abode-Iyamah K, Bydon M, Ames CP, Fogelson JL, Elder BD. Association between lower Hounsfield units and proximal junctional kyphosis and failure at the upper thoracic spine. J Neurosurg Spine 2022; 37:694-702. [PMID: 35561697 DOI: 10.3171/2022.3.spine22197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/30/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to analyze risk factors and avoidance techniques for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the upper thoracic spine with an emphasis on bone mineral density (BMD) as estimated by Hounsfield units (HU). METHODS A retrospective chart review identified patients at least 50 years of age who underwent instrumented fusion extending from the pelvis to an upper instrumented vertebra (UIV) between T1 and T6 and had a preoperative CT, pre- and postoperative radiographs, and a minimum follow-up of 12 months. HU were measured in the UIV, the vertebral body cephalad to the UIV (UIV+1), and the L3 and L4 vertebral bodies. Numerous perioperative variables were collected, including basic demographics, smoking and steroid use, preoperative osteoporosis treatment, multiple frailty indices, use of a proximal junctional tether, UIV soft landing, preoperative dual-energy x-ray absorptiometry, spinopelvic parameters, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, lumbar lordosis distribution, and postoperative spinopelvic parameters compared with age-adjusted normal values. RESULTS Eighty-one patients were included in the study (21 men and 60 women) with a mean (SD) age of 66 years (6.9 years), BMI of 29 (5.5), and follow-up of 38 months (25 months). Spinal fusion constructs at the time of surgery extended from the pelvis to a UIV of T1 (5%), T2 (15%), T3 (25%), T4 (33%), T5 (21%), and T6 (1%). Twenty-seven patients (33%) developed PJK and/or PJF; 21 (26%) had PJK and 15 (19%) had PJF. Variables associated with PJK/PJF with p < 0.05 were included in the multivariable analysis, including HU at the UIV/UIV+1, HU at L3/L4, DXA femoral neck T-score, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, and postoperative lumbar lordosis distribution. Multivariable analysis (area under the curve = 0.77) demonstrated HU at the UIV/UIV+1 to be the only independent predictor of PJK and PJF with an OR of 0.96 (p = 0.005). Patients with < 147 HU (n = 27), 147-195 HU (n = 27), and > 195 HU (n = 27) at the UIV/UIV+1 had PJK/PJF rates of 59%, 33%, and 7%, respectively. CONCLUSIONS In patients with upper thoracic-to-pelvis spinal reconstruction, lower HU at the UIV and UIV+1 were independently associated with PJK and PJF, with an optimal cutoff of 159 HU that maximizes sensitivity and specificity.
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Affiliation(s)
| | | | | | | | - Ahmad Nassr
- 2Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Brett Freedman
- 2Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Arjun S Sebastian
- 2Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota
| | | | - Mohamad Bydon
- 1Department of Neurological Surgery, Mayo Clinic, Rochester
| | - Christopher P Ames
- 4Department of Neurological Surgery, University of California, San Francisco, California
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23
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Vargas E, Mummaneni PV, Rivera J, Kolluri K, Berven S, Chou D. Adjacent Segment Vertebral Body Bone Density Changes as Measured By Hounsfield Units After Lumbar Spine Fusion. World Neurosurg 2022; 167:e464-e468. [PMID: 35964902 DOI: 10.1016/j.wneu.2022.08.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/06/2022] [Accepted: 08/08/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We sought to evaluate Hounsfield units (HU) at the adjacent segment after single-level transforaminal lumbar interbody fusion (TLIF) with preoperative and postoperative computed tomography scans. METHODS We performed a retrospective study on a series of patients who underwent L4-5 TLIF, from 2007 to 2017, by 3 spine surgeons at our institution. One-hundred and forty-three total patients were identified, and 41 patients with minimum 1-year follow-up met inclusion criteria. HU values were measured on preoperative and postoperative computed tomography at the adjacent L3 segment and at L1 as a control arm. Lumbar lordosis, pelvic tilt, pelvic incidence, sacral slope, and sagittal vertical axis were also collected preoperatively and postoperatively. RESULTS Mean preoperative HU value at L3 did not differ from the postoperative value (134.11 ± 47.14 mg/cm3 vs. 141.21 ± 55.14 mg/cm3, P = 0.34). Similarly, the mean preoperative HU value at the L1 control level region of interest did not differ from the postoperative value (150.17 ± 53.91 mg/cm3 vs. 145.78 ± 58.34 mg/cm3, P = 0.634). The interrater reliability of HU measurements was satisfactory with a resulting intraclass correlation coefficient of 0.76. CONCLUSIONS As measured by HU, we did not observe a change in bone density or other signs of adjacent segment disease at the L3 vertebral body 12 months after L4-5 TLIF. Spinopelvic parameters were not shown to be correlated with HU changes.
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Affiliation(s)
- Enrique Vargas
- Department of Neurosurgery, University of California, San Francisco, California, USA.
| | - Praveen V Mummaneni
- Department of Neurosurgery, University of California, San Francisco, California, USA
| | - Joshua Rivera
- Department of Neurosurgery, University of California, San Francisco, California, USA
| | - Kamal Kolluri
- Department of Neurosurgery, University of California, San Francisco, California, USA
| | - Sigurd Berven
- Department of Orthopedic Surgery, University of California, San Francisco, California, USA
| | - Dean Chou
- Department of Neurosurgery, University of California, San Francisco, California, USA
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24
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Lee M, Lee E, Lee JW. Value of computed tomography Hounsfield units in predicting pedicle screw loosening in the thoracic spine. Sci Rep 2022; 12:18279. [PMID: 36316434 PMCID: PMC9622837 DOI: 10.1038/s41598-022-23142-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/25/2022] [Indexed: 11/07/2022] Open
Abstract
We evaluated the feasibility of using the Hounsfield unit (HU) value of the vertebral body to predict screw loosening in the thoracic spine. Consecutive patients who underwent thoracic spinal fusion surgery (from 2014 to 2020) were retrospectively identified. Patients with pedicle screw loosening in the upper instrumented vertebra (UIV) on postoperative computed tomography were included in the "loosening" group. The control group comprised an equal number of age-, sex-, and UIV-matched patients without screw loosening. Preoperative HU values at the UIV and lumbar T-scores were compared between the groups; receiver operating characteristic curves were constructed for HU values and T-scores to predict screw loosening, and the best cutoff values were determined. The same statistical analyses were performed for each subgroup, i.e., upper (T1-T4) and lower (T9-T12) thoracic levels. Forty-six patients each were included in the loosening and control groups. A significant between-group difference of HU values was noted for the lower thoracic UIV (loosening = 99.3, control = 126.3; p = 0.02) but not for the upper thoracic UIV (loosening = 171.8, control = 146.0, p = 0.70). T-scores did not differ between the groups for the lower (p = 0.14) and upper (p = 0.56) thoracic UIV. For the lower thoracic UIV, the area under the receiver operating characteristic curve was 0.660 for HUs (p = 0.01; 95% confidence interval [CI] 0.541-0.766) and 0.601 (p = 0.13; 95% CI 0.480-0.713) for T-scores. The optimal cutoff value for HUs was 126.3. Using this cutoff, HU values showed a better positive predictive value, negative predictive value, and accuracy compared to T-scores in predicting screw loosening.
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Affiliation(s)
- Minsu Lee
- grid.412480.b0000 0004 0647 3378Department of Radiology, Seoul National University Bundang Hospital, 82, Gumiro 173beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do 13620 Republic of Korea
| | - Eugene Lee
- grid.412480.b0000 0004 0647 3378Department of Radiology, Seoul National University Bundang Hospital, 82, Gumiro 173beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do 13620 Republic of Korea
| | - Joon Woo Lee
- grid.412480.b0000 0004 0647 3378Department of Radiology, Seoul National University Bundang Hospital, 82, Gumiro 173beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do 13620 Republic of Korea ,grid.31501.360000 0004 0470 5905Department of Radiology, Seoul National University College of Medicine, 103, Daehak-ro, Jongno-gu, Seoul, 03080 Republic of Korea
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25
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Casciato DJ, Stone R, Thompson J, Venero M, Chiu M, Blum J, Barron I, Hyer C. Radiodensity Analysis of Medial Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy. J Foot Ankle Surg 2022; 61:1076-1080. [PMID: 35181205 DOI: 10.1053/j.jfas.2022.01.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/06/2021] [Accepted: 01/11/2022] [Indexed: 02/03/2023]
Abstract
Charcot neuroarthropathy (CN) is a highly destructive, pathologic process with devastating consequences to foot structure and viability. The use of intramedullary fixation "superconstructs" allows for "re-bar" support of compromised bone and allows for some dynamic fixation. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of medial column fixation targets using computed tomography scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of a circular region of interest centered on the first metatarsal head and the anterior, middle, and posterior thirds of the talar body. Radiodensity was compared between groups, and among talar locations, Eichenholtz stages and Brodsky types, with statistical significance set at p ≤ .05. Age and body mass index were not significantly different between groups. The CN group maintained greater mean HU than the control group at the metatarsal head (p < .001), and talar body locations (p < .019). The difference in mean HU of these bones was not statistically significant between Stages 0 to 1 and Stages 2 to 3 or Brodsky Types 1 and 2. Mean HU differences among talus positions were not statistically significant. Indirect bone density analysis using HU showed an increased density in CN patients with no significant difference among talar body locations or midfoot Charcot stages and types. These results may assist in optimizing fixation length. Future studies may examine these densities in ankle CN.
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Affiliation(s)
| | - Ryan Stone
- Resident Physician, OhioHealth Grant Medical Center, Columbus, OH
| | - John Thompson
- Resident Physician, OhioHealth Grant Medical Center, Columbus, OH
| | - Marissa Venero
- Resident Physician, Orlando VA Medical Center, Orlando, FL
| | - Michael Chiu
- Resident Physician, Orlando VA Medical Center, Orlando, FL
| | - Jonathan Blum
- Site Director, University of Central Florida College of Medicine, Orlando, FL
| | - Ian Barron
- Teaching Faculty, OhioHealth Grant Medical Center, Columbus, OH
| | - Christopher Hyer
- Fellowship Co-Director, Orthopedic Foot and Ankle Center, Worthington, OH
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Hiyama A, Sakai D, Katoh H, Sato M, Watanabe M. Relationship Between Hounsfield Units of Upper Instrumented Vertebrae, Proximal Junctional Failure, and Global Alignment and Proportion Score in Female Patients with Adult Spinal Deformity. World Neurosurg 2022; 164:e706-e717. [PMID: 35577209 DOI: 10.1016/j.wneu.2022.05.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 10/18/2022]
Abstract
STUDY DESIGN This was a retrospective observational study. OBJECTIVES The purpose of this study was to evaluate bone mineral density using Hounsfield unit (HU) values at the upper instrumented vertebrae (UIV), UIV+1, and UIV+2 and to investigate the association with proximal junctional failure (PJF) in female patients with adult spinal deformity (ASD). We also evaluated the relationship between the global alignment and proportion (GAP) score and the HU value of patients after ASD surgery. METHODS Fifty-two patients (52 females, mean age =70.2 years) who underwent multiple-level lateral lumbar interbody fusion combined with posterior instrumentation for ASD were included. The patients were divided into 2 groups, PJF and non-PJF. The demographics, surgical characteristics, and radiographic parameters were compared. Vertebral HU values at UIV, UIV+1, and UIV+2 using preoperative computed tomography scans and immediate postoperative GAP scores were also compared. RESULTS PJF was found in 13 of 52 patients (25.0%). Preoperative and postoperative thoracic kyphosis was large in PJF patients. Based on the total GAP score, there was no significant difference among the categories of GAP scores (P = 0.514). The statistically significant difference in mean HU values (116.6 ± 28.1 vs. 141.8 ± 41.8, P = 0.049) between the two groups at UIV. Further correlation analysis showed that the mean HU values in UIV and UIV+1 showed a significantly negative correlation coefficient with the total GAP score. CONCLUSIONS Our study suggests that preoperative HU values at UIV may affect the development of PJF for female ASD patients. HU evaluation by preoperative computed tomography may help reduce the incidence of PJF.
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Affiliation(s)
- Akihiko Hiyama
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
| | - Daisuke Sakai
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Hiroyuki Katoh
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Masato Sato
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Masahiko Watanabe
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan
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Bazán PL, Jordan RC, Cevallos JRM, Adaro AOG, Adaro JCS. HOUNSFIELD UNITS USE IN SPINAL SURGERY PLANNING: SYSTEMATIC REVIEW AND META-ANALYSIS. COLUNA/COLUMNA 2022. [DOI: 10.1590/s1808-185120222103264579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ABSTRACT Bone mineral density is a crucial factor in the success or failure of osteosynthesis in spine surgery; it shows the onset of osteoporosis and related complications. Its evaluation is verified by dual-energy X-ray absorptiometry (DEXA) and Hounsfield Unit (HU) measurement by CT scan. Objective: Determine the use of HU in surgical planning; compare utility in diagnosing osteoporosis by DEXA; and evaluate sensitivity in predicting complications. Method: A systemic literature review was conducted on PubMed, in line with PRISMA methodology. Including those who justified the use of pre-surgical planning, compared HU/DEXA, and assessed complications. For the statistical analysis, the χ2 was used. Results: 57 articles were identified by selecting nine that met the inclusion criteria. In patients undergoing spinal surgery for fixation and fusion for degenerative pathology, HU measurement showed a prevalence of osteoporosis of 58.5% (sensitivity 93.26%; specificity 90.22%), osteoporosis-associated complications of 24.5%, proper diagnosis of 71.98%, and screw release rate of 82.31%. Conclusions: UH measurement for the diagnosis of osteoporosis turns out to be more sensitive, specific, and predictive compared to DEXA, especially in elderly patients; it represents a useful tool in planning spinal surgery, minimizing the risk of complications such as screw release, fractures, pseudoarthrosis, subsidence of intersomatic devices, and kyphosis of the proximal junction. Level of evidence II; Study Design: Systematic Review and meta-analysis.
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Salzmann SN, Okano I, Jones C, Basile E, Iuso A, Zhu J, Reisener MJ, Chiapparelli E, Shue J, Carrino JA, Girardi FP, Cammisa FP, Sama AA, Hughes AP. Thoracic bone mineral density measured by quantitative computed tomography in patients undergoing spine surgery. Spine J 2021; 21:1866-1872. [PMID: 34022462 DOI: 10.1016/j.spinee.2021.05.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/10/2021] [Accepted: 05/12/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The thoracic spine is a common location for vertebral fractures as well as instrumentation failure after long spinal fusion procedures. The association between those complications and bone mineral density (BMD) are well recognized. Due to the overlying sternum and ribs in the thoracic spine, projectional BMD assessment tools such as dual energy x-ray absorptiometry (DXA) are limited to the lumbar spine. Quantitative computed tomography circumvents several shortcomings of DXA and allows for level-specific BMD measurements. Studies comprehensively quantifying BMD of the entire thoracic spine in patients undergoing spine surgery are limited. PURPOSE The objective of this study was: (1) to assess the reliability of thoracic QCT measurements, (2) to determine possible level-specific BMD variation throughout the thoracic spine and (3) to assess the correlation between BMDs of the T1-T12 spinal levels. STUDY DESIGN/SETTING Cross-sectional observation study. PATIENT SAMPLE Patients undergoing spine surgery from 2016-2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study. OUTCOME MEASURES The outcome measure was BMD measured by QCT. METHODS Patients undergoing spine surgery from 2016-2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study. Subjects with previous instrumentation at any thoracic level, concurrent vertebral fractures, a Cobb angle of more than 20 degrees, or incomplete thoracic spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of T1-T12 were performed. To assess inter- and intra-observer reliability, a validation study was performed on 120 vertebrae in 10 randomly selected patients. The interclass correlation coefficient (ICC) was calculated. A pairwise comparison of BMD was conducted and correlations between each thoracic level were evaluated. The statistical significance level was set at p<.05. RESULTS 60 patients (men, 51.7%) met inclusion criteria. The study population was 90% Caucasian with a mean age of 62.2 years and a mean BMI of 30.2 kg/m2. The inter- and intra-observer reliability of the thoracic QCT measurements was excellent (ICC of 0.97 and 0.97, respectively). The trabecular BMD was highest in the upper thoracic spine and decreased in the caudal direction (T1 = 182.3 mg/cm3, T2 = 168.1 mg/cm3, T3 = 163.5 mg/cm3, T4 = 164.7 mg/cm3, T5 = 161.4 mg/cm3, T6 = 152.5 mg/cm3, T7 = 143.5 mg/cm3, T8 = 141.3 mg/cm3, T9 = 143.5 mg/cm3, T10 = 145.1 mg/cm3, T11 = 145.3 mg/cm3, T12 = 133.6 mg/cm3). The BMD of all thoracic levels cranial to T6 was statistically higher than the BMD of all levels caudal to T6 (p < .001). Nonetheless, significant correlations in BMD among all measured thoracic levels were observed, with a Pearson's correlation coefficient ranging from 0.74 to 0.97. CONCLUSIONS There is significant regional BMD variation in the thoracic spine depending on spinal level. This BMD variation might contribute to several clinically relevant phenomena. First, vertebral fractures occur most commonly at the thoracolumbar junction including T12. In addition to mechanical reasons, these fractures might be partially attributed to thoracic BMD that is lowest at T12. Second, the optimal upper instrumented vertebra (UIV) for stopping long fusions to the sacrum and pelvis is controversial. The BMD of surgically relevant upper thoracic stopping points (T2-T4) was significantly higher than the BMD of lower thoracic stopping points (T10-T12). Besides stress concentration at the relatively mobile lower thoracic segments, the low BMD at these levels might contribute to previously suggested higher rates of junctional failures with short fusions.
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Affiliation(s)
- Stephan N Salzmann
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Ichiro Okano
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Conor Jones
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Eric Basile
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Anthony Iuso
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Jiaqi Zhu
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Marie-Jacqueline Reisener
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Erika Chiapparelli
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Jennifer Shue
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - John A Carrino
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Federico P Girardi
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Frank P Cammisa
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Andrew A Sama
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA
| | - Alexander P Hughes
- Spine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, 535 East 70th St, New York, NY 10021, USA.
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Mikula AL, Fogelson JL, Lakomkin N, Flanigan PM, Pinter ZW, Doan MK, Bydon M, Nassr A, Freedman B, Sebastian AS, Abode-Iyamah K, Anderson PA, Elder BD. Lower Hounsfield Units at the Upper Instrumented Vertebrae are Significantly Associated With Proximal Junctional Kyphosis and Failure Near the Thoracolumbar Junction. Oper Neurosurg (Hagerstown) 2021; 21:270-275. [PMID: 34171907 DOI: 10.1093/ons/opab236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 05/03/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Low bone mineral density (BMD) on dual energy x-ray absorptiometry (DXA) is likely a risk factor for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, prior instrumentation and degenerative changes can preclude a lumbar BMD measurement. Hounsfield units (HU) represent an alternative method to estimate BMD via targeted measurements at the intended operative levels. OBJECTIVE To determine if patients with lower HU at the upper instrumented vertebrae (UIV) and vertebral body superior to the UIV (UIV + 1) are at greater risk for PJK and PJF. METHODS A retrospective chart review identified patients at least 50 yr of age who underwent instrumented lumbar fusion with pelvic fixation, a UIV from T10 to L2, and a preoperative computed tomography (CT) encompassing the UIV. HU were measured at the UIV, UIV + 1, and the L3-L4 vertebral bodies. RESULTS A total of 150 patients (80 women and 70 men) were included with an average age of 66 yr and average follow-up of 32 mo. Multivariable logistic regression analysis with an area under the curve (AUC) of 0.89 demonstrated HU at the UIV/UIV + 1 as the only independent predictor of PJK/PJF with an odds ratio of 0.94 (P-value = .031) for a change in a single HU. Patients with HU at UIV/UIV + 1 of <110 (n = 35), 110 to 160 (n = 73), and >160 (n = 42) had a rate of PJK/PJF of 63%, 27%, and 12%, respectively (P-value < .001). CONCLUSION Patients with lower HU at the UIV and UIV + 1 were significantly associated with PJK and PJF, with an optimal cutoff of 122 HU that maximizes sensitivity and specificity.
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Affiliation(s)
- Anthony L Mikula
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Jeremy L Fogelson
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Nikita Lakomkin
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Patrick M Flanigan
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Zachariah W Pinter
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Mohamad Bydon
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Ahmad Nassr
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Brett Freedman
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Arjun S Sebastian
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Paul A Anderson
- Department of Orthopedics and Rehabilitative Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Benjamin D Elder
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA
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