Assessment of impact of standing long-cassette radiographs on surgical planning for lumbar pathology: an international survey of spine surgeons

Do we really apply evidence-based-recommendations to spine surgery? Results of an international survey

OBJECTIVE

This international survey investigated Evidence-Based Medicine (EBM) in spine surgery by measuring its acceptance among spine surgeons. It assessed their understanding of EBM and how they apply it in practice by analyzing responses to various clinical scenarios..

MATERIALS AND METHODS

Following the CHERRIES guidelines, an e-survey was distributed to multiple social media forums for neurosurgeons and orthopedic surgeons on Facebook, LinkedIn, and Telegram and circulated further through email via the authors' network. Three hundred participants from Africa, Asia, Europe, North America, and Oceania completed the survey.

RESULTS

Our study revealed that 67.7% (n = 203) of respondents used EBM in their practice, and 97.3% (n = 292) believed training in research methodology and EBM was necessary for the practice of spine surgery. Despite this endorsement of using EBM in spine surgery, we observed varied responses to how EBM is applied in practice based on example scenarios. The responders who had additional training tended to obey EBM guidelines more than those who had no additional training. Most surgeons responded as always or sometimes prescribing methylprednisolone to patients with acute spinal cord injury. Other significant differences were identified between geographical regions, training, practice settings, and other factors.

CONCLUSIONS

Most respondents used EBM in practice and believed training in research methodology and EBM is necessary for spine surgery; however, there were significant variations on how to use them per case. Thus, the appropriate application of EBM in clinical settings for spinal surgery must be further studied.

Spine Surgery and Ankylosing Spondylitis: Optimizing Perioperative Management

Ankylosing spondylitis (AS) is a common form of axial spondyloarthritis, characterized by inflammatory back pain, radiographic sacroiliitis, excess spinal bone formation, and a high prevalence of HLA-B27. Commonly, AS patients require spinal surgery for kyphotic deformities, spinal trauma, and spinal infections. For preoperative management, proper interruption considering each specific half-lives of disease-modifying antirheumatic drugs are necessary to avoid complications, such as infections. When feasible, bone quality assessment before surgery is mandatory. For intraoperative measurements, airway management should be carefully evaluated, especially in patients with severe cervical deformities. Cardiac, renal, and pulmonary assessment should be made considering specific pathologic characteristics involved in AS patients, such as pulmonary restrictive disease and chronic anti-inflammatory drugs use. Multimodal neurophysiological intraoperative monitoring is recommended once these patients had a high risk for neurological deterioration. At the postoperative period, early oral intake, early mobilization, and aggressive pain control may decrease complications and enhance recovery. AS presents several unique challenges that require specific attention around spine surgery. This includes handling preoperative and postoperative pharmacotherapeutics, intraoperative airway management, and the mitigation of postoperative complications. In this paper, we provide a literature review of optimal strategies for the perioperative management for patients with AS.

The Impact of Radiographic Lower Limb-Spinal Length Proportion on Whole-Body Sagittal Alignment

STUDY DESIGN

A radiographic comparative study.

OBJECTIVE

To investigate the influence of radiographic lower limb-spinal length proportion on sagittal radiographic parameters.

SUMMARY OF BACKGROUND DATA

Although lordotic realignment of the lumbar spine is a well-established surgical strategy, its ideal target has not been fully understood. The widely used pelvic incidence-lumbar lordosis discrepancy (PI-LL) method to guide lordotic restoration of the lumber spine in the standing posture, may be further refined using the novel, radiographic lower limb-spinal length proportion parameter in selected subjects.

METHODS

A 100 healthy subjects were imaged in the standing posture using EOS imaging to obtain whole-body lateral radiographs for the measurement of sagittal radiographic parameters. Univariate analyses were performed to compare radiographic parameters between groups with different radiographic lower limb-spinal length proportion. Multivariate analyses were performed to identify the associations between lower limb-spinal length proportions and other radiographic parameters.

RESULTS

Regardless of lower limb-spinal length proportion (mean = 1.4), global lumbar angle (GLA) differed from spinal lordosis (SL), with the absolute means of SL and GLA larger and smaller than pelvic incidence (PI) respectively. Univariate analysis showed that patients with proportionately larger lower limb-spinal length proportion are more likely to have larger mean T1-slope, global thoracic angle (GTA), spinal kyphosis (SK), GLA, and SL. Multivariate analysis showed that a larger lower limb length-spinal length proportion is predictive of larger GLA is less than -47.69° (Odds Ratio (OR) 2.660, P = 0.026), and larger T1-slope of more than 18.84° (OR 3.695, P = 0.012).

CONCLUSION

Larger radiographic lower limb-spinal length proportion results in naturally accentuated spinal curves. These patients balance with a larger lumbar lordosis that is closer to the PI and a higher T1-slope which should be considered for spinal realignment. SL differs from GLA and should be separately assessed.Level of Evidence: 3.

Measurement of Spinopelvic Angles on Prone Intraoperative Long-Cassette Lateral Radiographs Predicts Postoperative Standing Global Alignment in Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective review from a single institution.

OBJECTIVES

To evaluate intraoperative T1-pelvic angle (TPA), T4PA, and T9PA as predictors of postoperative global alignment after adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Malalignment following adult spinal surgery is associated with disability and correlates with health-related quality of life. Preoperative planning and intraoperative verification are crucial for optimal postoperative outcomes. Currently, only pelvic incidence minus lumbar lordosis (PI-LL) mismatch has been used to assess intraoperative correction.

METHODS

Patients undergoing ≥4-level spinal fusion with full-length pre-, intra-, and first postoperative calibrated radiographs were included from a single institution. Alignment measurements were obtained for sagittal vertical axis (SVA), PI-LL, TPA, T4PA, and T9PA. The whole cohort was divided into upper thoracic (UT: UIV > T7) and lower thoracic fusions (LT: UIV < T7). Change was assessed between phases, and a subanalysis was included for UT and LT groups to compare alignment changes for differing extent of proximal fusion in the sagittal plane.

RESULTS

Eighty patients (mean 63.4 years, 70% female, mean levels fused 11.9) underwent significant ASD correction (ΔPI-LL = 22.1°; ΔTPA = 13.8°). For all, intraoperative TPA, T4PA, and T9PA correlated with postoperative SVA (range, r = 0.41-0.59), whereas intraoperative PI-LL correlated less (r = 0.38). For UT (n = 49), all spinopelvic angles and LL were similar intraoperative to postoperatively (p > .09). For LT (n = 31), intraoperative and postoperative T9PA and LL were similar (p > .10) but TPA and T4PA differed (p < .02). For UT, all intraoperative and postoperative spinopelvic angles strongly correlated (r = 0.8-0.9). For LT, intraoperative to postoperative T9PA strongly correlated (r = 0.83) and TPA, T4PA, and LL correlated moderately (r = 0.65-0.70). LT trended toward more reciprocal kyphosis postoperatively (8.1° vs. 2.6°; p = .059).

CONCLUSIONS

Intraoperative measurements of TPA, T4PA, and T9PA correlated better with postoperative global alignment than PI-LL, demonstrating their utility in confirming alignment goals. When comparing intraoperative to postoperative films, only T9PA was similar in LT whereas all spinopelvic angles were similar in UT. Reciprocal kyphosis in unfused segments of LT fusions may account for difference in TPA and T4PA from intraoperative to postoperative films.

LEVEL OF EVIDENCE

Level III.

Postoperative Change of Thoracic Kyphosis after Corrective Surgery for Adult Spinal Deformity

Introduction

Correction of lumbar lordosis is the primary goal of surgical treatment of adult spinal deformity. However, only limited research has evaluated the effects of this correction on the adaptive curvature of the thoracic spine. The purpose of this study is to evaluate the change in thoracic curvature after corrective surgery to restore lumbar lordosis in patients with adult spinal deformity.

Methods

We completed a retrospective analysis of the radiological data of 65 patients, ≥50 years old, who underwent corrective surgery of lumbar spine lordosis from any level below T8 to the ilium. Patients with insufficient correction, defined by a pelvic incidence minus lumbar lordosis angle (PI-LL) > 10°, were excluded, with the data of 43 patients included in the analysis. The following radiological measures of spinal alignment were measured at three time points, preoperatively, on the first day of standing postoperatively and at 2 years post-surgery: sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), and PI-LL.

Results

Postoperative change in TK was correlated to preoperative TK and age. The increase in TK was larger for patients <75 years of age, increasing from 23.1° to 38.0° after surgery and to 46.7° at 2-years postoperatively. In contrast, for patients >75 years, TK remained largely unchanged at 37.8° just after surgery but increased substantively to 50.1° at the 2-year follow-up. The postoperative change in TK immediately after surgery was determined using equation “predict change in TK = −0.21 × age − 0.6 × preoperative TK + 41.8” by multiple regression analysis.

Conclusions

Reciprocal change in TK after lumbar spine correction is correlated to preoperative TK and age.

Validation of prone intraoperative measurements of global spinal alignment

OBJECTIVE

Verifying the adequacy of surgical correction of adult spinal sagittal deformity (SSD) leads to improved postoperative alignment and clinical outcomes. Traditionally, surgeons relied on intraoperative measurements of lumbar lordosis (LL) correction. However, T-1 pelvic angle (TPA) and its component angles more reliably predict postoperative alignment. While TPA is readily measured on standing radiographs, intraoperative radiographs offer poor resolution of the bicoxofemoral axis. A method to recreate this radiographic landmark by extrapolating preoperative measurements has been described. The authors aimed to assess the reliability of measurements of global spinal alignment obtained via geometrical reconstitution of the bicoxofemoral axis on prone intraoperative radiographs.

METHODS

A retrospective review was performed. Twenty sets of preoperative standing full-length and intraoperative prone 36-inch lateral radiographs were analyzed. Pelvic incidence (PI) and sacral to bicoxofemoral axis distance (SBFD) were recorded on preoperative films. A perpendicular line was drawn on the intraoperative radiograph from the midpoint of the sacral endplate. This was used as one limb of the PI, and the second limb was digitally drawn at an angle that reproduced the preoperatively obtained PI, extending for a distance that matched the preoperative SBFD. This final point marked the obscured bicoxofemoral axis. These landmarks were used to measure the L-1, T-9, T-4, and T-1 pelvic angles (LPA, T9PA, T4PA, and TPA, respectively) and LL. Two spine fellows and 2 attending spine surgeons made independent measurements and repeated the process in 1 month. Mixed-model 2-way intraclass correlation coefficient (ICC) and Cronbach’s α values were calculated to assess interobserver, intraobserver, and scale reliability.

RESULTS

Interobserver reliability was excellent for preoperative PI and intraoperative LPA, T9PA, and T4PA (ICC = 0.88, 0.84, 0.84, and 0.93, respectively), good for intraoperative TPA (ICC = 0.68), and fair for preoperative SBFD (ICC = 0.60) and intraoperative LL (ICC = 0.50). Cronbach’s α was ≥ 0.80 for all measurements. Measuring PI on preoperative standing images had excellent intraobserver reliability for all raters (ICC = 0.89, range 0.80–0.93). All raters but one showed excellent reliability for measuring the SBFD. Reliability for measuring prone LL was good for all raters (ICC = 0.71, range 0.64–0.76). The LPA demonstrated good to excellent reliability for each rater (ICC = 0.76, range 0.65–0.81). The thoracic pelvic angles tended to be more reliable at more distal vertebrae (T9PA ICC = 0.71, range 0.49–0.81; T4PA ICC = 0.62, range 0.43–0.83; TPA ICC = 0.56, range 0.31–0.86).

CONCLUSIONS

Intraoperative assessment of global spinal alignment with TPA and component angles is more reliable than intraoperative measurements of LL. Reconstruction of preoperatively measured PI and SBFD on intraoperative radiographs effectively overcomes poor visualization of the bicoxofemoral axis. This method is easily adopted and produces accurate and reliable prone intraoperative measures of global spinal alignment.

Intra- and Interrater Reliability of Sagittal Spinopelvic Parameters on Full-Spine Radiographs in Adults With Symptomatic Spinal Disorders

Background/Aims

To evaluate the intra- and interrater reliability (I-IR) of sagittal spinopelvic parameters from digital full-spine plain radiographs with basic software tools in an unselected adult population with degenerative spinal complaints who were evaluated for surgery.

Methods

Forty-nine adult full-spine digital radiographs were measured twice by 3 independent observers, including an experienced spine surgeon, an experienced radiologist, and a resident orthopedic surgeon. Clinical picture archiving and communication system workstations and software tools were used and landmarks were set manually. The I-IR of the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), and thoracic kyphosis in T4–T12 (TK) were assessed.

Results

The intrarater intraclass correlation coefficient (ICC) scores varied from 0.82 to 0.99. The interrater ICC scores ranged from 0.78 to 0.99. The intrarater standard error of measurement (SEM) values for SS, PT, PI, and TK varied from 0.8° to 5.0°, and the interrater SEM values ranged from 2.5° to 6.2°, depending on the parameter and the reading round. The I-IR SEM values for SVA varied from 2.2 to 5.7 mm and from 4.6 to 5.0 mm, respectively. Kappa values were >0.88 for all readers. The intrarater variability was the smallest for the most experienced rater.

Conclusion

The I-IR of measuring sagittal spinopelvic parameters on digital full-spine images with basic software tools was high. Parameters consisting of several anatomic landmarks were more liable to error. Rater experience had a positive influence on reliability and repeatability. Reader experience should be assessed before accepting measurements for surgical planning and the interpretation of surgical correction during postoperative follow-up.

Complication rates associated with 3-column osteotomy in 82 adult spinal deformity patients: retrospective review of a prospectively collected multicenter consecutive series with 2-year follow-up

OBJECTIVE Although 3-column osteotomy (3CO) can provide powerful alignment correction in adult spinal deformity (ASD), these procedures are complex and associated with high complication rates. The authors' objective was to assess complications associated with ASD surgery that included 3CO based on a prospectively collected multicenter database. METHODS This study is a retrospective review of a prospectively collected multicenter consecutive case registry. ASD patients treated with 3CO and eligible for 2-year follow-up were identified from a prospectively collected multicenter ASD database. Early (≤ 6 weeks after surgery) and delayed (> 6 weeks after surgery) complications were collected using standardized forms and on-site coordinators. RESULTS Of 106 ASD patients treated with 3CO, 82 (77%; 68 treated with pedicle subtraction osteotomy [PSO] and 14 treated with vertebral column resection [VCR]) had 2-year follow-up (76% women, mean age 60.7 years, previous spine fusion in 80%). The mean number of posterior fusion levels was 12.9, and 17% also had an anterior fusion. A total of 76 early (44 minor, 32 major) and 66 delayed (13 minor, 53 major) complications were reported, with 41 patients (50.0%) and 45 patients (54.9%) affected, respectively. Overall, 64 patients (78.0%) had at least 1 complication, and 50 (61.0%) had at least 1 major complication. The most common complications were rod breakage (31.7%), dural tear (20.7%), radiculopathy (9.8%), motor deficit (9.8%), proximal junctional kyphosis (PJK, 9.8%), pleural effusion (8.5%), and deep wound infection (7.3%). Compared with patients who did not experience early or delayed complications, those who had these complications did not differ significantly with regard to age, sex, body mass index, Charlson Comorbidity Index, American Society of Anesthesiologists score, smoking status, history of previous spine surgery or spine fusion, or whether the 3CO performed was a PSO or VCR (p ≥ 0.06). Twenty-seven (33%) patients had 1-11 reoperations (total of 44 reoperations). The most common indications for reoperation were rod breakage (n = 14), deep wound infection (n = 15), and PJK (n = 6). The 24 patients who did not achieve 2-year follow-up had a mean of 0.85 years of follow-up, and the types of early and delayed complications encountered in these 24 patients were comparable to those encountered in the patients that achieved 2-year follow-up. CONCLUSIONS Among 82 ASD patients treated with 3CO, 64 (78.0%) had at least 1 early or delayed complication (57 minor, 85 major). The most common complications were instrumentation failure, dural tear, new neurological deficit, PJK, pleural effusion, and deep wound infection. None of the assessed demographic or surgical parameters were significantly associated with the occurrence of complications. These data may prove useful for surgical planning, patient counseling, and efforts to improve the safety and cost-effectiveness of these procedures.

Early experience with endoscopic foraminotomy in patients with moderate degenerative deformity

OBJECTIVE Asymmetrical degeneration of the disc is one of the most common causes of primary degenerative scoliosis in adults. Coronal deformity is usually less symptomatic than a sagittal deformity because there is less expenditure of energy and hence less effort to maintain upright posture. However, nerve root compression at the fractional curve or at the concave side of the main curve can give rise to debilitating radiculopathy. METHODS This study was a retrospective analysis of 16 patients with coronal deformity of between 10° and 20°. All patients underwent endoscopic foraminal decompression surgery. The pre- and postoperative Cobb angle, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36), and Oswestry Disability Index scores were measured. RESULTS The average age of the patients was 70.0 ± 15.5 years (mean ± SD, range 61-86 years), with a mean followup of 7.5 ± 5.3 months (range 2-14 months). The average coronal deformity was 16.8° ± 4.7° (range 10°-41°). In 8 patients the symptomatic foraminal stenosis was at the level of the fractional curve, and in the remaining patients it was at the concave side of the main curve. One of the patients included in the current cohort had to undergo a repeat operation within 1 week for another disc herniation at the adjacent level. One patient had CSF leakage, which was repaired intraoperatively, and no further complications were noted. On average, preoperative VAS and SF-36 scores showed a tendency for improvement, whereas a dramatic reduction of VAS, by 65% (p = 0.003), was observed in radicular leg pain. CONCLUSIONS Patients with mild to moderate spinal deformity are often compensated and have tolerable levels of back pain. However, unilateral radicular pain resulting from foraminal stenosis can be debilitating. In select cases, an endoscopic discectomy or foraminotomy enables the surgeon to decompress the symptomatic foramen with preservation of essential biomechanical structures, delaying the need for a major deformity correction surgery.

Prospective multicenter assessment of perioperative and minimum 2-year postoperative complication rates associated with adult spinal deformity surgery

OBJECTIVE Although multiple reports have documented significant benefit from surgical treatment of adult spinal deformity (ASD), these procedures can have high complication rates. Previously reported complications rates associated with ASD surgery are limited by retrospective design, single-surgeon or single-center cohorts, lack of rigorous data on complications, and/or limited follow-up. Accurate definition of complications associated with ASD surgery is important and may serve as a resource for patient counseling and efforts to improve the safety of patient care. The authors conducted a study to prospectively assess the rates of complications associated with ASD surgery with a minimum 2-year follow-up based on a multicenter study design that incorporated standardized data-collection forms, on-site study coordinators, and regular auditing of data to help ensure complete and accurate reporting of complications. In addition, they report age stratification of complication rates and provide a general assessment of factors that may be associated with the occurrence of complications. METHODS As part of a prospective, multicenter ASD database, standardized forms were used to collect data on surgery-related complications. On-site coordinators and central auditing helped ensure complete capture of complication data. Inclusion criteria were age older than 18 years, ASD, and plan for operative treatment. Complications were classified as perioperative (within 6 weeks of surgery) or delayed (between 6 weeks after surgery and time of last follow-up), and as minor or major. The primary focus for analyses was on patients who reached a minimum follow-up of 2 years. RESULTS Of 346 patients who met the inclusion criteria, 291 (84%) had a minimum 2-year follow-up (mean 2.1 years); their mean age was 56.2 years. The vast majority (99%) had treatment including a posterior procedure, 25% had an anterior procedure, and 19% had a 3-column osteotomy. At least 1 revision was required in 82 patients (28.2%). A total of 270 perioperative complications (145 minor; 125 major) were reported, with 152 patients (52.2%) affected, and a total of 199 delayed complications (62 minor; 137 major) were reported, with 124 patients (42.6%) affected. Overall, 469 complications (207 minor; 262 major) were documented, with 203 patients (69.8%) affected. The most common complication categories included implant related, radiographic, neurological, operative, cardiopulmonary, and infection. Higher complication rates were associated with older age (p = 0.009), greater body mass index (p ≤ 0.031), increased comorbidities (p ≤ 0.007), previous spine fusion (p = 0.029), and 3-column osteotomies (p = 0.036). Cases in which 2-year follow-up was not achieved included 2 perioperative mortalities (pulmonary embolus and inferior vena cava injury). CONCLUSIONS This study provides an assessment of complications associated with ASD surgery based on a prospective, multicenter design and with a minimum 2-year follow-up. Although the overall complication rates were high, in interpreting these findings, it is important to recognize that not all complications are equally impactful. This study represents one of the most complete and detailed reports of perioperative and delayed complications associated with ASD surgery to date. These findings may prove useful for treatment planning, patient counseling, benchmarking of complication rates, and efforts to improve the safety and cost-effectiveness of patient care.

Assessment of Impact of Long-Cassette Standing X-Rays on Surgical Planning for Cervical Pathology

BACKGROUND:

Understanding the role of regional segments of the spine in maintaining global balance has garnered significant attention recently. Long-cassette radiographs (LCR) are necessary to evaluate global spinopelvic alignment. However, it is unclear how LCRs impact operative decision-making for cervical spine pathology.

OBJECTIVE:

To evaluate whether the addition of LCRs results in changes to respondents' operative plans compared to standard imaging of the involved cervical spine in an international survey of spine surgeons.

METHODS:

Fifteen cases (5 control cases with normal and 10 test cases with abnormal global alignment) of cervical pathology were presented online with a vignette and cervical imaging. Surgeons were asked to select a surgical plan from 6 options, ranging from the least (1 point) to most (6 points) extensive. Cases were then reordered and presented again with LCRs and the same surgical plan question.

RESULTS:

One hundred fifty-seven surgeons completed the survey, of which 79% were spine fellowship trained. The mean response scores for surgical plan increased from 3.28 to 4.0 (P = .003) for test cases with the addition of LCRs. However, no significant changes (P = .10) were identified for the control cases. In 4 of the test cases with significant mid thoracic kyphosis, 29% of participants opted for the more extensive surgical options of extension to the mid and lower thoracic spine when they were provided with cervical imaging only, which significantly increased to 58.3% upon addition of LCRs.

CONCLUSION:

In planning for cervical spine surgery, surgeons should maintain a low threshold for obtaining LCRs to assess global spinopelvic alignment.