Assessment of Surgical Treatment Strategies for Moderate to Severe Cervical Spinal Deformity Reveals Marked Variation in Approaches, Osteotomies, and Fusion Levels

Vertebral Column Decancellation for Correcting Cervicothoracic Kyphotic Deformity in Patients With Ankylosing Spondylitis

OBJECTIVE

Surgery to correct the cervicothoracic kyphotic deformity in ankylosing spondylitis (AS) can be associated with serious neurovascular risks. According to the literature, there are no clinical reports documenting the use of vertebral column decancellation (VCD) in the treatment of cervicothoracic kyphotic deformity in patients with AS. The purpose of the present study was to retrospectively analyze and evaluate the effect of VCD on cervicothoracic kyphotic deformity in patients with AS.

METHODS

Records of eight patients with cervicothoracic kyphotic deformity who underwent VCD at C7 in our institution were retrospectively reviewed. The mean duration of clinical follow-up after surgery was 19 months. The cervical lordosis (CL) and C2-C7 sagittal vertical axis (SVA) were meticulously measured on full-length spine radiographs. The chin-brow vertical angle (CBVA) was measured on clinical photographs. Outcome measures utilized included the Neck Disability Index (NDI), the Japanese Orthopaedic Association (JOA) Score, and a Visual Analog Scale (VAS) for neck pain. The data analysis was performed using SPSS version 26.0 for Windows. For paired data adhering to a normal distribution, we utilized paired sample t-tests to analyze preoperative and postoperative imaging parameters. Statistical significance was established at a p value threshold of < 0.01.

RESULTS

All eight patients successfully completed the surgery. With an average VCD osteotomy angle of 47.6° ± 8.1° (±SD), the mean preoperative CBVA was 81.1° ± 17.6° (±SD), while the immediate postoperative value was 19.9° ± 5.7° (±SD). The overall average correction was 61.2° ± 18.9°. The mean preoperative cervical sagittal imbalance was 93.4 ± 27.3 mm (±SD), while the immediate postoperative value was 40.2 ± 18.9 mm (±SD). The overall average correction was 53.2 ± 28.1 mm. None of the eight patients experienced intraoperative complications, including nerve or vascular injury, cerebrospinal fluid leakage, or any other related complications. In the cohort of eight patients, the mean values for estimated blood loss, surgical time, and hospital stay were 1313 mL, 248 min, and 18 days, respectively. In comparison to preoperative scores, statistically significant improvement was noted in all patients in the postoperative period with regard to NDI, JOA, and VAS (p < 0.01, using a paired t-test).

CONCLUSION

The VCD procedure proves to be a dependable and efficient approach for addressing cervicothoracic kyphotic deformities. It achieves remarkable corrections in cervical kyphosis and CBVA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: 2400090375.

A Meta-Analysis of Surgical Outcomes in 25727 Patients Undergoing Anterior Cervical Discectomy and Fusion or Anterior Cervical Corpectomy and Fusion for Cervical Deformity

STUDY DESIGN

Systematic Review.

OBJECTIVES

To evaluate which cervical deformity correction technique between anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) produces better clinical, radiographic, and operative outcomes.

METHODS

We conducted a meta-analysis comparing studies involving ACDF and ACCF. Adult patients with either original or previously treated cervical spine deformities were included. Two independent reviewers categorized extracted data into clinical, radiographic, and operative outcomes, including complications. Clinical assessments included patient-reported outcomes; radiographic evaluations examined C2-C7 Cobb angle, T1 slope, T1-CL, C2-7 SVA, and graft stability. Surgical measures included surgery duration, blood loss, hospital stay, and complications.

RESULTS

26 studies (25727 patients) met inclusion criteria and were extracted. Of these, 14 studies (19077 patients) with low risk of bias were included in meta-analysis. ACDF and ACCF similarly improve clinical outcomes in terms of JOA and NDI, but ACDF is significantly better at achieving lower VAS neck scores. ACDF is also more advantageous for improving cervical lordosis and minimizing the incidence of graft complications. While there is no significant difference between approaches for most surgical complications, ACDF is favorable for reducing operative time, intraoperative blood loss, and length of hospital stay.

CONCLUSIONS

While both techniques benefit cervical deformity patients, when both techniques are feasible, ACDF may be superior with respect to VAS neck scores, cervical lordosis, graft complications and certain perioperative outcomes. Further studies are recommended to address outcome variability and refine surgical approach selection.

Adult cervical spine deformity: a state-of-the-art review

Adult cervical deformity is a structural malalignment of the cervical spine that may present with variety of significant symptomatology for patients. There are clear and substantial negative impacts of cervical spine deformity, including the increased burden of pain, limited mobility and functionality, and interference with patients' ability to work and perform everyday tasks. Primary cervical deformities develop as the result of a multitude of different etiologies, changing the normal mechanics and structure of the cervical region. In particular, degeneration of the cervical spine, inflammatory arthritides and neuromuscular changes are significant players in the development of disease. Additionally, cervical deformities, sometimes iatrogenically, may present secondary to malalignment or correction of the thoracic, lumbar or sacropelvic spine. Previously, classification systems were developed to help quantify disease burden and influence management of thoracic and lumbar spine deformities. Following up on these works and based on the relationship between the cervical and distal spine, Ames-ISSG developed a framework for a standardized tool for characterizing and quantifying cervical spine deformities. When surgical intervention is required to correct a cervical deformity, there are advantages and disadvantages to both anterior and posterior approaches. A stepwise approach may minimize the drawbacks of either an anterior or posterior approach alone, and patients should have a surgical plan tailored specifically to their cervical deformity based upon symptomatic and radiographic indications. This state-of-the-art review is based upon a comprehensive overview of literature seeking to highlight the normal cervical spine, etiologies of cervical deformity, current classification systems, and key surgical techniques.

Optimizing Surgical Strategy for Cervical Spinal Deformity: Global Alignment and Surgical Targets

Cervical spinal deformity (CSD) is a complex condition characterized by abnormal curvature and cervical spine alignment. It can lead to a multitude of symptoms, including chronic pain, neurological deficits, and functional impairments, severely impacting an individual's health-related quality of life (HRQoL). Surgical intervention is often necessary to address the deformity and alleviate symptoms, but optimal surgical strategies remain a topic of ongoing research and debate. This narrative review aims to provide an in-depth overview of the surgical management of CSD, focusing on optimizing patient outcomes and enhancing readers' understanding of the complexities involved. We begin by discussing the importance of preoperative assessment, including comprehensive radiographic evaluation and careful consideration of the global spinal alignment. The relationship between the cervical spine and the reciprocal changes that occur are explored to guide surgeons in their decision-making process. Furthermore, we delve into the selection of fusion levels, emphasizing the significance of identifying the primary driver of deformity. We review the current literature on optimal alignment targets and strategies to optimize surgical planning. By providing a comprehensive analysis of the surgical management of CSD, this review aims to enhance the readers' knowledge and assist surgeons in making informed decisions when planning and executing surgical interventions. Understanding the intricacies of CSD correction and the latest advancements in the field can ultimately improve patient outcomes and enhance HRQoL for individuals suffering from this challenging condition.

Adult Cervical Deformity Patients Have Higher Baseline Frailty, Disability, and Comorbidities Compared With Complex Adult Thoracolumbar Deformity Patients: A Comparative Cohort Study of 616 Patients

STUDY DESIGN

Multicenter comparative cohort.

OBJECTIVE

Studies have shown markedly higher rates of complications and all-cause mortality following surgery for adult cervical deformity (ACD) compared with adult thoracolumbar deformity (ATLD), though the reasons for these differences remain unclear. Our objectives were to compare baseline frailty, disability, and comorbidities between ACD and complex ATLD patients undergoing surgery.

METHODS

Two multicenter prospective adult spinal deformity registries were queried, one ATLD and one ACD. Baseline clinical and frailty measures were compared between the cohorts.

RESULTS

616 patients were identified (107 ACD and 509 ATLD). These groups had similar mean age (64.6 vs 60.8 years, respectively, P = .07). ACD patients were less likely to be women (51.9% vs 69.5%, P < .001) and had greater Charlson Comorbidity Index (1.5 vs .9, P < .001) and ASA grade (2.7 vs 2.4, P < .001). ACD patients had worse VR-12 Physical Component Score (PCS, 25.7 vs 29.9, P < .001) and PROMIS Physical Function Score (33.3 vs 35.3, P = .031). All frailty measures were significantly worse for ACD patients, including hand dynamometer (44.6 vs 55.6 lbs, P < .001), CSHA Clinical Frailty Score (CFS, 4.0 vs 3.2, P < .001), and Edmonton Frailty Scale (EFS, 5.15 vs 3.21, P < .001). Greater proportions of ACD patients were frail (22.9% vs 5.7%) or vulnerable (15.6% vs 10.9%) based on EFS (P < .001).

CONCLUSIONS

Compared with ATLD patients, ACD patients had worse baseline characteristics on all measures assessed (comorbidities/disability/frailty). These differences may help account for greater risk of complications and all-cause mortality previously observed in ACD patients and facilitate strategies for better preoperative optimization.

Cervical sagittal alignment changes following anterior cervical discectomy and fusion, laminectomy with fusion, and laminoplasty for multisegmental cervical spondylotic myelopathy

OBJECTIVE

Cervical sagittal alignment changes (CSACs) influence outcomes and health-related quality-of-life. Anterior cervical discectomy and fusion (ACDF), laminectomy with fusion (LCF), and laminoplasty (LP) are common treatments for multisegmental cervical spondylotic myelopathy; however, these approaches need to be compared.

METHODS

Our study included 167 patients who underwent ACDF, LCF, or LP. Patients were divided into four groups according to C2-C7 Cobb angle (CL): kyphosis (CL < 0°), straight (0° ≤ CL < 10°), lordosis (10° ≤ CL < 20°), and extreme lordosis (20° ≤ CL) groups. CSACs consist of two parts. CSAC from the preoperative period to the postoperative period is surgical correction change (SCC). CSAC from the postoperative period to the final follow-up period is postoperative lordosis preserving (PLP). Outcomes were evaluated using the Japanese Orthopaedic Association score and the neck disability index.

RESULTS

ACDF, LCF, and LP had equivalent outcomes. ACDF had greater SCC than LCF and LP. During follow-up, lordosis decreased in the ACDF and LCF groups but increased in the LP group. For straight alignment, ACDF had greater CSAC and greater SCC than the LCF and LP groups but similar PLP. For lordosis alignment, ACDF and LP had positive PLP, and LCF had negative PLP. For extreme lordosis, ACDF, LP, and LCF had negative PLP; however, cervical lordosis in the LP group was relatively stable during follow-up.

CONCLUSIONS

ACDF, LCF, and LP have different CSAC, SCC, and PLP according to a four-type cervical sagittal alignment classification. Preoperative cervical alignment is an important consideration in deciding the type of surgical treatment in CSM.

Effect of cervical suspensory traction in the treatment of severe cervical kyphotic deformity

Objective

This study aimed to investigate a new noninvasive traction method on the treatment of severe cervical kyphotic deformity.

Methods

The clinical data of patients with severe cervical kyphosis (Cobb > 40°) treated in Peking University Third Hospital from March 2004 to March 2020 were retrospectively summarized. 46 cases were enrolled, comprising 27 males and 19 females. Fifteen patients underwent skull traction, and 31 patients underwent suspensory traction. Among them, seven used combined traction after one week of suspensory traction. Bedside lateral radiographs were taken every two or three days during traction. The cervical kyphosis angle was measured on lateral radiographs in and extended position at each point in time. The correction rate and evaluated Japanese Orthopedic Association (JOA) scoring for the function of the spinal cord were also measured. The data before and after the operation were compared with paired sample t-test or Wilcoxon signed-rank test.

Results

No neurological deterioration occurred during the skull traction and the cervical suspensory traction. There were 12 patients with normal neurological function, and the JOA score of the other 34 patients improved from 11.5 ± 2.8 to 15.4 ± 1.8 at the end of follow up (P < 0.05). The average kyphotic Cobb angle was 66.1° ± 25.2, 28.7° ± 20.1 and 17.4° ± 25.7 pre-traction, pre-operative, and at the final follow-up, respectively (P < 0.05). The average correction rate of skull traction and suspensory traction was 34.2% and 60.6% respectively. Among these, the correction rate of patients with simple suspensory traction was 69.3%. For patients with a correction rate of less than 40% by suspensory traction, combined traction was continued, and the correction rates after suspensory traction and combined traction were 30.7% and 67.1% respectively.

Conclusions

Pre-correction by cervical suspensory traction can achieve good results for severe cervical kyphotic deformity, with no wound and an easy process. Combined traction is effective for supplemental traction after suspensory traction.

Operative treatment outcomes for adult cervical deformity: a prospective multicenter assessment with mean 3-year follow-up

OBJECTIVE

Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery.

METHODS

A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up.

RESULTS

Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2-8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up.

CONCLUSIONS

This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors' knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

Evolution of Adult Cervical Deformity Surgery Clinical and Radiographic Outcomes Based on a Multicenter Prospective Study: Are Behaviors and Outcomes Changing With Experience?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Assess changes in outcomes and surgical approaches for adult cervical deformity surgery over time.

SUMMARY OF BACKGROUND DATA

As the population ages and the prevalence of cervical deformity increases, corrective surgery has been increasingly seen as a viable treatment. Dramatic surgical advancements and expansion of knowledge on this procedure have transpired over the years, but the impact on cervical deformity surgery is unknown.

MATERIALS AND METHODS

Adult cervical deformity patients (18 yrs and above) with complete baseline and up to the two-year health-related quality of life and radiographic data were included. Descriptive analysis included demographics, radiographic, and surgical details. Patients were grouped into early (2013-2014) and late (2015-2017) by date of surgery. Univariate and multivariable regression analyses were used to assess differences in surgical, radiographic, and clinical outcomes over time.

RESULTS

A total of 119 cervical deformity patients met the inclusion criteria. Early group consisted of 72 patients, and late group consisted of 47. The late group had a higher Charlson Comorbidity Index (1.3 vs. 0.72), more cerebrovascular disease (6% vs. 0%, both P <0.05), and no difference in age, frailty, deformity, or cervical rigidity. Controlling for baseline deformity and age, late group underwent fewer three-column osteotomies [odds ratio (OR)=0.18, 95% confidence interval (CI): 0.06-0.76, P =0.014]. At the last follow-up, late group had less patients with: a moderate/high Ames horizontal modifier (71.7% vs. 88.2%), and overcorrection in pelvic tilt (4.3% vs. 18.1%, both P <0.05). Controlling for baseline deformity, age, levels fused, and three-column osteotomies, late group experienced fewer adverse events (OR=0.15, 95% CI: 0.28-0.8, P =0.03), and neurological complications (OR=0.1, 95% CI: 0.012-0.87, P =0.03).

CONCLUSION

Despite a population with greater comorbidity and associated risk, outcomes remained consistent between early and later time periods, indicating general improvements in care. The later cohort demonstrated fewer three-column osteotomies, less suboptimal realignments, and concomitant reductions in adverse events and neurological complications. This may suggest a greater facility with less invasive techniques.

Neurological Complications and Recovery Rates of Patients With Adult Cervical Deformity Surgeries

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

This study aims to report the incidence, risk factors, and recovery rate of neurological complications (NC) in patients with adult cervical deformity (ACD) who underwent corrective surgery.

METHODS

ACD patients undergoing surgery from 2013 to 2015 were enrolled in a prospective, multicenter database. Patients were separated into 2 groups according to the presence of neurological complications (NC vs no-NC groups). The types, timing, recovery patterns, and interventions for NC were recorded. Patients' demographics, surgical details, radiographic parameters, and health-related quality of life (HRQOL) scores were compared.

RESULTS

106 patients were prospectively included. Average age was 60.8 years with a mean of 18.2 months follow-up. The overall incidence of NC was 18.9%; of these, 68.1% were major complications. Nerve root motor deficit was the most common complication, followed by radiculopathy, sensory deficit, and spinal cord injury. The proportion of complications occurring within 30 days of surgery was 54.5%. The recovery rate from neurological complication was high (90.9%), with most of the recoveries occurring within 6 months and continuing even after 12 months. Only 2 patients (1.9%) had continuous neurological complication. No demographic or preoperative radiographic risk factors could be identified, and anterior corpectomy and posterior foraminotomy were found to be performed less in the NC group. The final HRQOL outcome was not significantly different between the 2 groups.

CONCLUSIONS

Our data is valuable to surgeons and patients to better understand the neurological complications before performing or undergoing complex cervical deformity surgery.

"The Circle" Predicts Extent of Fusion for Surgical Correction of Cervical Spinal Kyphotic Deformities: Proof of Concept

BACKGROUND

Correction of kyphotic deformities of the spine is a common problem faced by spine surgeons. Unfortunately, there are no clear published guidelines available regarding the extent of spinal fusion required to achieve and maintain lasting deformity correction.

OBJECTIVE

The authors aim to share a set of novel radiographic parameter ("the Circle") that can be used as a guideline for determining the extent of fusion required in surgical correction of spinal kyphotic deformity.

METHODS

A Google forms survey was distributed amongst spine surgeons and trainees to evaluate differences in recommend extent of posterior-approach fusions for cervical spinal kyphotic deformities before and after introduction to "the Circle". Extent of fusion before and after use of "the Circle" were qualitatively and quantitatively analyzed. Data was anonymized and stored in a secure database.

RESULTS

Twenty-seven neurosurgical attendings (n=14), residents (n=9) and fellows (n=3) responded to the survey. Variance between predicted upper and lower instrumented vertebrae, and length of construct, was statistically significantly decreased after application of "the Circle" in almost all cases. Respondents rated the ease of use of "the Circle" an average of 4.2/5 (5 = the most ease). The majority of participants (92/6%; n=25/27) stated that they would or would likely use "the Circle" as a radiographic tool in the surgical planning for correction of cervical spinal kyphotic deformities in the future.

CONCLUSION

"The Circle" is a novel radiographic parameter that may be used to educate and guide surgical plans and extent of fusion when aiming to correct spinal kyphotic deformities.

Predictive model for achieving good clinical and radiographic outcomes at one-year following surgical correction of adult cervical deformity

Background

For cervical deformity (CD) surgery, goals include realignment, improved patient quality of life, and improved clinical outcomes. There is limited research identifying patients most likely to achieve all three.

Objective

The objective is to create a model predicting good 1-year postoperative realignment, quality of life, and clinical outcomes following CD surgery using baseline demographic, clinical, and radiographic factors.

Methods

Retrospective review of a multicenter CD database. CD patients were defined as having one of the following radiographic criteria: Cervical sagittal vertical axis (cSVA) >4 cm, cervical kyphosis/scoliosis >10°° or chin-brow vertical angle >25°. The outcome assessed was whether a patient achieved both a good radiographic and clinical outcome. The primary analysis was stepwise regression models which generated a dataset-specific prediction model for achieving a good radiographic and clinical outcome. Model internal validation was achieved by bootstrapping and calculating the area under the curve (AUC) of the final model with 95% confidence intervals.

Results

Seventy-three CD patients were included (61.8 years, 58.9% F). The final model predicting the achievement of a good overall outcome (radiographic and clinical) yielded an AUC of 73.5% and included the following baseline demographic, clinical, and radiographic factors: mild-moderate myelopathy (Modified Japanese Orthopedic Association >12), no pedicle subtraction osteotomy, no prior cervical spine surgery, posterior lowest instrumented vertebra (LIV) at T1 or above, thoracic kyphosis >33°°, T1 slope <16 and cSVA <20 mm.

Conclusions

Achievement of a positive outcome in radiographic and clinical outcomes following surgical correction of CD can be predicted with high accuracy using a combination of demographic, clinical, radiographic, and surgical factors, with the top factors being baseline cSVA <20 mm, no prior cervical surgery, and posterior LIV at T1 or above.

Surgical Strategy for the Management of Cervical Deformity Is Based on Type of Cervical Deformity

Objectives: Cervical deformity morphotypes based on type and location of deformity have previously been described. This study aimed to examine the surgical strategies implemented to treat these deformity types and identify if differences in treatment strategies impact surgical outcomes. Our hypothesis was that surgical strategies will differ based on different morphologies of cervical deformity. Methods: Adult patients enrolled in a prospective cervical deformity database were classified into four deformity types (Flatneck (FN), Focal kyphosis (FK), Cervicothoracic kyphosis (CTK) and Coronal (C)), as previously described. We analyzed group differences in demographics, preoperative symptoms, health-related quality of life scores (HRQOLs), and surgical strategies were evaluated, and postop radiographic and HROQLs at 1+ year follow up were compared. Results: 90/109 eligible patients (mean age 63.3 ± 9.2, 64% female, CCI 1.01 ± 1.36) were evaluated. Group distributions included FN = 33%, FK = 29%, CTK = 29%, and C = 9%. Significant differences were noted in the surgical approaches for the four types of deformities, with FN and FK having a high number of anterior/posterior (APSF) approaches, while CTK and C had more posterior only (PSF) approaches. For FN and FK, PSF was utilized more in cases with prior anterior surgery (70% vs. 25%). For FN group, PSF resulted in inferior neck disability index compared to those receiving APSF suggesting APSF is superior for FN types. CTK types had more three-column osteotomies (3CO) (p < 0.01) and longer fusions with the LIV below T7 (p < 0.01). There were no differences in the UIV between all deformity types (p = 0.19). All four types of deformities had significant improvement in NRS neck pain post-op (p < 0.05) with their respective surgical strategies. Conclusions: The four types of cervical deformities had different surgical strategies to achieve improvements in HRQOLs. FN and FK types were more often treated with APSF surgery, while types CTK and C were more likely to undergo PSF. CTK deformities had the highest number of 3COs. This information may provide guidelines for the successful management of cervical deformities.

Utility of intraoperative neuromonitoring and outcomes of neurological complication in lower cervical and upper thoracic posterior-based three-column osteotomies for cervical deformity

OBJECTIVE

For severe and rigid adult cervical deformity, posterior-based three-column osteotomies (3COs) are warranted, but neurological complications are relatively high with such procedures. The performance measures of intraoperative neuromonitoring (IONM) during cervicothoracic 3CO have yet to be studied, and there remains a paucity of literature regarding the topic. Therefore, the authors of this study examined the performance of IONM in predicting new neurological weakness following lower cervical and upper thoracic 3CO. In addition, they report the 6-month, 1-year, and 2-year outcomes of patients who experienced new postoperative weakness.

METHODS

The authors performed a retrospective review of a single surgeon's experience from 2011 to 2018 with all patients who had undergone posterior-based 3CO in the lower cervical (C7) or upper thoracic (T1-4) spine. Medical and neuromonitoring records were independently reviewed.

RESULTS

A total of 56 patients were included in the analysis, 38 of whom had undergone pedicle subtraction osteotomy and 18 of whom had undergone vertebral column resection. The mean age was 61.6 years, and 41.1% of the patients were male. Among the study cohort, 66.1% were myelopathic and 33.9% had preoperative weakness. Mean blood loss was 1565.0 ml, and length of surgery was 315.9 minutes. Preoperative and postoperative measures assessed were cervical sagittal vertical axis (6.5 and 3.8 cm, respectively; p < 0.001), cervical lordosis (2.3° and -6.7°, p = 0.042), and T1 slope (48.6° and 35.8°, p < 0.001). The complication rate was 49.0%, and the new neurological deficit rate was 17.9%. When stratifying by osteotomy level, there were significantly higher rates of neurological deficits at C7 and T1: C7 (37.5%), T1 (44.4%), T2 (16.7%), T3 (14.3%), and T4 (0.0%; p = 0.042). Most new neurological weakness was the nerve root pattern rather than the spinal cord pattern. Overall, there were 16 IONM changes at any threshold: 14 at 50%, 8 at 75%, and 13 if only counting patients who did not return to baseline (RTB). Performance measures for the various thresholds were accuracy (73.2% to 77.8%), positive predictive value (25.0% to 46.2%), negative predictive value (81.3% to 88.1%), sensitivity (18.2% to 54.5%), and specificity (77.8% to 86.7%). Sensitivity to detect a spinal cord pattern of weakness was 100% and 28.6% for a nerve root pattern of weakness. In patients with a new postoperative deficit, 22.2% were unchanged, 44.4% improved, and 33.3% had a RTB at the 2-year follow-up.

CONCLUSIONS

Complication rates are high following posterior 3CO for cervical deformity. 3CO at C7 and T1 has the highest rates of neurological deficit. Current IONM modalities have modest performance in predicting postoperative deficits, especially for nerve root neuropraxia. A large prospective multicenter study is warranted.

The impact of preoperative supine radiographs on surgical strategy in adult spinal deformity

OBJECTIVE

Preoperative planning for adult spinal deformity (ASD) surgery is essential to prepare the surgical team and consistently obtain postoperative alignment goals. Positional imaging may allow the surgeon to evaluate spinal flexibility and anticipate the need for more invasive techniques. The purpose of this study was to determine whether spine flexibility, defined by the change in alignment between supine and standing imaging, is associated with the need for an osteotomy in ASD surgery.

METHODS

A single-center, dual-surgeon retrospective analysis was performed of adult patients with ASD who underwent correction of a thoracolumbar deformity between 2014 and 2018 (pelvis to upper instrumented vertebra between L1 and T9). Patients were stratified into osteotomy (Ost) and no-osteotomy (NOst) cohorts according to whether an osteotomy was performed (Schwab grade 2 or higher). Demographic, surgical, and radiographic parameters were compared. The sagittal correction from intraoperative prone positioning alone (sagittal flexibility percentage [Sflex%]) was assessed by comparing the change in lumbar lordosis (LL) between preoperative supine to standing radiographs and preoperative to postoperative alignment.

RESULTS

Demographics and preoperative and postoperative sagittal alignment were similar between the Ost (n = 60, 65.9%) and NOst (n = 31, 34.1%) cohorts (p > 0.05). Of all Ost patients, 71.7% had a grade 2 osteotomy (mean 3 per patient), 21.7% had a grade 3 osteotomy, and 12.5% underwent both grade 3 and grade 2 osteotomies. Postoperatively, the NOst and Ost cohorts had similar pelvic incidence minus lumbar lordosis (PI-LL) mismatch (mean PI-LL 5.2° vs 1.2°; p = 0.205). Correction obtained through positioning (Sflex%) was significantly lower for in the osteotomy cohort (38.0% vs 76.3%, p = 0.004). A threshold of Sflex% < 70% predicted the need for osteotomy at a sensitivity of 78%, specificity of 56%, and positive predictive value of 77%.

CONCLUSIONS

The flexibility of the spine is quantitatively related to the use of an osteotomy. Prospective studies are needed to determine thresholds that may be used to standardize surgical decision-making in ASD surgery.

Cervicothoracic Versus Proximal Thoracic Lower Instrumented Vertebra Have Comparable Radiographic and Clinical Outcomes in Adult Cervical Deformity

STUDY DESIGN

Comparative cohort study.

OBJECTIVE

Factors that influence the lower instrumented vertebra (LIV) selection in adult cervical deformity (ACD) are less reported, and outcomes in the cervicothoracic junction (CTJ) and proximal thoracic (PT) spine are unclear.

METHODS

A prospective ACD database was analyzed using the following inclusion criteria: LIV between C7 and T5, upper instrumented vertebra at C2, and at least a 1-year follow-up. Patients were divided into CTJ (LIV C7-T2) and PT groups (LIV T3-T5) based on LIV levels. Demographics, operative details, radiographic parameters, and the health-related quality of life (HRQOL) scores were compared.

RESULTS

Forty-six patients were included (mean age, 62 years), with 22 and 24 patients in the CTJ and PT groups, respectively. Demographics and surgical parameters were comparable between the groups. The PT group had a significantly higher preoperative C2-C7 sagittal vertical axis (cSVA) (46.9 mm vs 32.6 mm, P = 0.002) and T1 slope minus cervical lordosis (45.9° vs 36.0°, P = 0.042) than the CTJ group and was more likely treated with pedicle-subtraction osteotomy (33.3% vs 0%, P = 0.004). The PT group had a larger correction of cSVA (-7.7 vs 0.7 mm, P = 0.037) and reciprocal change of increased T4-T12 kyphosis (8.6° vs 0.0°, P = 0.001). Complications and reoperations were comparable. The HRQOL scores were not different preoperatively and at 1-year follow-up.

CONCLUSIONS

The selection of PT LIV in cervical deformities was more common in patients with larger baseline deformities, who were more likely to undergo pedicle-subtraction osteotomy. Despite this, the complications and HRQOL outcomes were comparable at 1-year follow-up.

Factors which predict adverse events following surgery in adults with cervical spinal deformity

AIMS

The aim of this study was to identify the risk factors for adverse events following the surgical correction of cervical spinal deformities in adults.

METHODS

We identified adult patients who underwent corrective cervical spinal surgery between 1 January 2007 and 31 December 2015 from the MarketScan database. The baseline comorbidities and characteristics of the operation were recorded. Adverse events were defined as the development of a complication, an unanticipated deleterious postoperative event, or further surgery. Patients aged < 18 years and those with a previous history of tumour or trauma were excluded from the study.

RESULTS

A total of 13,549 adults in the database underwent primary corrective surgery for a cervical spinal deformity during the study period. A total of 3,785 (27.9%) had a complication within 90 days of the procedure, and 3,893 (28.7%) required further surgery within two years. In multivariate analysis, male sex (odds ratio (OR) 0.90 (95% confidence interval (CI) 0.8 to 0.9); p = 0.019) and a posterior approach (compared with a combined surgical approach, OR 0.66 (95% CI 0.5 to 0.8); p < 0.001) significantly decreased the risk of complications. Osteoporosis (OR 1.41 (95% CI 1.3 to 1.6); p < 0.001), dyspnoea (OR 1.48 (95% CI 1.3 to 1.6); p < 0.001), cerebrovascular accident (OR 1.81 (95% CI 1.6 to 2.0); p < 0.001), a posterior approach (compared with an anterior approach, OR 1.23 (95% CI 1.1 to 1.4); p < 0.001), and the use of bone morphogenic protein (BMP) (OR 1.22 (95% CI 1.1 to 1.4); p = 0.003) significantly increased the risks of 90-day complications. In multivariate regression analysis, preoperative dyspnoea (OR 1.50 (95% CI 1.3 to 1.7); p < 0.001), a posterior approach (compared with an anterior approach, OR 2.80 (95% CI 2.4 to 3.2; p < 0.001), and postoperative dysphagia (OR 2.50 (95% CI 1.8 to 3.4); p < 0.001) were associated with a significantly increased risk of further surgery two years postoperatively. A posterior approach (compared with a combined approach, OR 0.32 (95% CI 0.3 to 0.4); p < 0.001), the use of BMP (OR 0.48 (95% CI 0.4 to 0.5); p < 0.001) were associated with a significantly decreased risk of further surgery at this time.

CONCLUSION

The surgical approach and intraoperative use of BMP strongly influence the risk of further surgery, whereas the comorbidity burden and the characteristics of the operation influence the rates of early complications in adult patients undergoing corrective cervical spinal surgery. These data may aid surgeons in patient selection and surgical planning. Cite this article: Bone Joint J 2021;103-B(4):734-738.

Degenerative Adult Cervical Kyphosis With Secondary Diagnosis Codes Are Associated With Higher Cost and Complications After Spinal Fusion: A Medicare Database Study

BACKGROUND

Adult cervical deformity (ACD) is a potentially debilitating condition resulting from kyphosis, scoliosis, or both, of the cervical spine. Conditions such as ankylosing spondylitis, rheumatoid arthritis, Parkinson's disease, and neuromuscular diseases are particularly known to cause severe deformities. We describe the 90-day cost and complications associated with spinal fusion for ACD using International Classification of Diseases (ICD) coding terminology and study if secondary diagnoses associated with potential for severe deformity affect the cost and complication profile of ACD surgery.

METHODS

Medicare data were used to study hospital costs and complications within 90 days after primary cervical fusion for ACD in 2 cohorts matched by demographics and comorbidity burden: (1) patients with diagnoses of secondary pathology (SP) known to cause severe deformity and (2) without SP. Univariate and multiple-variable analyses to study incidence of complications, readmission, and costs within 90 days were done.

RESULTS

A total of 2900 patients in matched cohorts of 1450 each were included. The mean index hospital payment ($26 545 ± $25 968 versus $22 991 ± $21 599) and length of stay (4.8 ± 5.6 versus 3.9 ± 4.5 days) was significantly (P < .01) higher in ACD patients with SP. On adjusted analysis, the risk of procedure-related complications was higher (odds ratio [OR] = 1.47, 95% confidence interval [CI], 1.18-1.83) in patients with SP than those without SP, but not readmission (OR = 1.04, 95% CI, 0.82-1.32) or refusion (OR = 0.95, 95% CI, 0.45-2.0) within 90 days. The cost profile of complications, readmission, and refusion has been given.

CONCLUSIONS

ACD patients with secondary diagnosis codes such as inflammatory arthropathy or neuromuscular pathology incur higher 90-day costs due to the inherent requirement of bigger fusions and higher risk of peri-operative complications, but with similar risk of readmission and refusion as those without SP.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

With evolving health care reforms and payment models, knowledge of conditions associated with higher expenditure after elective spine surgical procedures will be beneficial to providers and payors for appropriate risk stratification.

Risk factors for determining length of intensive care unit and hospital stays following correction of cervical deformity: evaluation of early severe adverse events

OBJECTIVE

Correction of rigid cervical deformities can be associated with high complication rates and result in prolonged intensive care unit (ICU) and hospital stays. In this study, the authors aimed to examine the risk factors contributing to length of stay (LOS) in both the hospital and ICU following adult cervical deformity (ACD) surgery and to identify severe adverse events that occurred in this setting.

METHODS

A retrospective review of ACD patients who underwent posterior-based osteotomies for deformity correction from 2010 to 2019 was performed. Inclusion criteria were cervical kyphosis > 20° and/or cervical sagittal vertical axis (cSVA) > 4 cm. Multivariate analysis was used to identify risk factors independently associated with ICU and hospital LOS.

RESULTS

A total of 107 patients were included. The mean age was 63.5 years, and 61.7% were female. Over half (52.3%) underwent 3-column osteotomies, while 47.7% underwent posterior column osteotomies. There was significant correction of all cervical parameters: cSVA (6.0 vs 3.6 cm, p < 0.001), cervical lordosis (8.2° vs -5.3°, p < 0.001), cervical scoliosis (6.5° vs 2.2°, p < 0.001), and T1-slope (40.2° vs 34.5°, p < 0.001). There were also reciprocal changes to the distal spine: thoracic kyphosis (54.4° vs 46.4°, p < 0.001), lumbar lordosis (49.9° vs 45.8°, p = 0.003), and thoracolumbar scoliosis (13.9° vs 11.1°, p = 0.009). Overall, 4 patients (3.7%) suffered aspiration-related complications, 3 patients (2.8%) experienced dysphagia requiring a feeding tube, and 4 patients (3.7%) had compromised airways, with 1 resulting in death. The mean ICU and hospital LOS were 2.8 days and 7.9 days, respectively. Multivariate analysis identified three factors independently associated with longer ICU LOS: female sex (3.0 vs 2.4 days, p = 0.004), ≥ 12 segments fused (3.5 vs 1.9 days, p = 0.002), and postoperative complication (4.0 vs 1.9 days, p = 0.017). These same factors were independently associated with longer hospital LOS as well: female sex (8.3 vs 7.3 days, p = 0.013), ≥ 12 segments fused (9.4 vs 6.2 days, p = 0.001), and complication (9.7 vs 6.7 days, p = 0.026).

CONCLUSIONS

Posterior-based osteotomies are very effective for the correction of ACD, but postoperative hospital stays are relatively longer than those following surgery for degenerative disease. Risk factors for prolonged ICU and hospital LOS consist of both nonmodifiable (female sex) and modifiable (≥ 12 segments fused and presence of complication) risk factors. Additional multicenter prospective studies will be needed to validate these findings.

Apoptosis of endplate chondrocytes in cervical kyphosis is associated with chronic forward flexed neck: an in vivo rat bipedal walking model

BACKGROUND

This study was undertaken to establish a rat bipedal walking model of cervical kyphosis (CK) associated with chronic forward flexed neck and assess the effects of chronic forward flexed neck on endplate chondrocytes.

METHODS

Forty-eight 1-month-old Sprague-Dawley rats were randomly divided into 3 groups: forward flexed neck group (n = 16), bipedal group (n = 16), and normal group (n = 16). Cervical curves were analyzed on a lateral cervical spine X-ray using Harrison's posterior tangent method before the experiment and at 2-week intervals for a 6-week period. Histologic changes in cartilaginous endplate chondrocytes were observed using hematoxylin and eosin (H&E) staining, transmission electron microscopy (TEM), and terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick-end labeling.

RESULTS

Radiographic findings suggested a significantly decreased cervical physiological curvature in the forward flexed neck group over the 6-week follow-up; normal cervical curves were maintained in other groups. The average cervical curvature (C2-C7) was - 7.6 ± 0.9° in the forward flexed neck group before the experiment, - 3.9 ± 0.8° at 2 weeks post-experiment, 10.7 ± 1.0° at 4 weeks post-experiment, and 20.5 ± 2.1° at the last follow-up post-experiment. Histologically, results of H&E staining unveiled that cartilaginous endplate chondrocytes were arranged in an irregular fashion, with the decreased number at the observation period; the incidence of apoptotic cells in the forward flexed neck group was noticeably higher at the 6-week follow-up than that in other groups.

CONCLUSIONS

CK developed as the result of chronic forward flexed neck. Histologic changes suggested that chondrocyte apoptosis may play a critical role in the development of cervical kyphotic deformity associated with chronic forward flexed neck.

Congenital Osseous Torticollis that Mimics Congenital Muscular Torticollis: A Retrospective Observational Study

It may be difficult to diagnose congenital osseous torticollis based on physical examinations or plain X-rays, especially when children have no other accompanying congenital defects. This study reports the children with torticollis caused by the vertebral anomaly with the symptom of abnormal head and neck posture only. We retrospectively reviewed the records of 1015 patients diagnosed with congenital torticollis in a single tertiary hospital (Incheon St. Mary’s Hospital, Korea) who were referred from a primary local clinic. We included those with deficits in passive range of motion (PROM) of neck. Ultrasonography of the sternocleidomastoid (SCM) muscles, ophthalmologic and neurologic examinations, and cervical X-rays were performed for all patients. If bony malalignment was suspected from X-ray, three-dimensional volume-rendered computed tomography (3D-CT) was performed. Ten patients were diagnosed with osseous torticollis with no defect other than bony anomalies. Although X-ray images were acquired for all patients, vertebral anomalies were definitely confirmed in three cases (30.0%) only, and the others (70.0%) were confirmed by CT. The most common type of vertebral anomaly was single-level fusion. Identifying congenital vertebral anomalies is challenging especially when the degree of invasion is only one level. Although abnormal findings on X-rays may be subtle, a careful examination must be performed to avoid misdiagnosis.

Prospective multicenter assessment of complication rates associated with adult cervical deformity surgery in 133 patients with minimum 1-year follow-up

OBJECTIVE

Although surgical treatment can provide significant improvement of symptomatic adult cervical spine deformity (ACSD), few reports have focused on the associated complications. The objective of this study was to assess complication rates at a minimum 1-year follow-up based on a prospective multicenter series of ACSD patients treated surgically.

METHODS

A prospective multicenter database of consecutive operative ACSD patients was reviewed for perioperative (< 30 days), early (30-90 days), and delayed (> 90 days) complications with a minimum 1-year follow-up. Enrollment required at least 1 of the following: cervical kyphosis > 10°, cervical scoliosis > 10°, C2-7 sagittal vertical axis > 4 cm, or chin-brow vertical angle > 25°.

RESULTS

Of 167 patients, 133 (80%, mean age 62 years, 62% women) had a minimum 1-year follow-up (mean 1.8 years). The most common diagnoses were degenerative (45%) and iatrogenic (17%) kyphosis. Almost 40% of patients were active or past smokers, 17% had osteoporosis, and 84% had at least 1 comorbidity. The mean baseline Neck Disability Index and modified Japanese Orthopaedic Association scores were 47 and 13.6, respectively. Surgical approaches were anterior-only (18%), posterior-only (47%), and combined (35%). A total of 132 complications were reported (54 minor and 78 major), and 74 (56%) patients had at least 1 complication. The most common complications included dysphagia (11%), distal junctional kyphosis (9%), respiratory failure (6%), deep wound infection (6%), new nerve root motor deficit (5%), and new sensory deficit (5%). A total of 4 deaths occurred that were potentially related to surgery, 2 prior to 1-year follow-up (1 cardiopulmonary and 1 due to obstructive sleep apnea and narcotic use) and 2 beyond 1-year follow-up (both cardiopulmonary and associated with revision procedures). Twenty-six reoperations were performed in 23 (17%) patients, with the most common indications of deep wound infection (n = 8), DJK (n = 7), and neurological deficit (n = 6). Although anterior-only procedures had a trend toward lower overall (42%) and major (21%) complications, rates were not significantly different from posterior-only (57% and 33%, respectively) or combined (61% and 37%, respectively) approaches (p = 0.29 and p = 0.38, respectively).

CONCLUSIONS

This report provides benchmark rates for ACSD surgery complications at a minimum 1-year (mean 1.8 years) follow-up. The marked health and functional impact of ACSD, the frail population it affects, and the high rates of surgical complications necessitate a careful risk-benefit assessment when contemplating surgery. Collectively, these findings provide benchmarks for complication rates and may prove useful for patient counseling and efforts to improve the safety of care.

Three-Column Osteotomy for the Treatment of Rigid Cervical Deformity

Adult cervical deformity (ACD) has been shown to have a substantial impact on quality of life and overall health, with moderate to severe deformities resulting in significant disability and dysfunction. Fortunately, surgical management and correction of cervical sagittal imbalance can offer significant benefits and improvement in pain and disability. ACD is a heterogenous disease and specific surgical correction strategies should reflect deformity type (driver of deformity) and patient-related factors. Spinal rigidity is one of the most important considerations as soft tissue releases and osteotomies play a crucial role in cervical deformity correction. For ankylosed, fixed, and severe deformity, 3-column osteotomy (3CO) is often warranted. A 3CO can be done through combined anteriorposterior (vertebral body resection) and posterior-only approaches (open or closed wedge pedicle subtraction osteotomies [PSOs]). This article reviews the literature for currently published studies that report results on the use of 3CO for ACD, with a special concentration on posterior based 3CO (open and closed wedge PSO). More specifically, this review discusses the indications, radiographic corrective ability, and associated complications.

Anterior Reconstruction Techniques for Cervical Spine Deformity

Cervical spine deformity is an uncommon yet severely debilitating condition marked by its heterogeneity. Anterior reconstruction techniques represent a familiar approach with a range of invasiveness and correction potential-including global or focal realignment in the sagittal and coronal planes. Meticulous preoperative planning is required to improve or prevent neurologic deterioration and obtain satisfactory global spinal harmony. The ability to perform anterior only reconstruction requires mobility of the opposite column to achieve correction, unless a combined approach is planned. Anterior cervical discectomy and fusion has limited focal correction, but when applied over multiple levels there is a cumulative effect with a correction of approximately 6° per level. Partial or complete corpectomy has the ability to correct sagittal deformity as well as decompress the spinal canal when there is anterior compression behind the vertebral body. If pathoanatomy permits, a hybrid discectomy-corpectomy construct is favored over multilevel corpectomies. The anterior cervical osteotomy with bilateral complete uncinectomy may be necessary for angular correction of fixed cervical kyphosis, and is particularly useful in the midcervical spine. A detailed understanding of the patient's local anatomy, careful attention to positioning, and avoiding long periods of retraction time will help prevent complications and iatrogenic injury.

Utility of a Novel Biomimetic Spine Model in Surgical Education: Case Series of Three Cervicothoracic Kyphotic Deformities

STUDY DESIGN

Evaluation of new technology.

OBJECTIVES

To evaluate the utility of a novel biomimetic spine model as a surgical planning and education resource in the treatment of cervical spine deformities (CSD).

METHODS

Three patients with CSD were identified and synthetic spine models were manufactured to match the anatomical and biomechanical properties of each patient. Each model underwent 3 phases of surgical correction: maximum correction with no osteotomies performed, with posterior column osteotomies (PCOs) only, and with PCOs and a 3-column osteotomy (3CO). Lateral fluoroscopic films were obtained after each phase of correction for measurement of cervical lordosis. Surgeons were surveyed to obtain subjective feedback on the perceived model utility.

RESULTS

Each model began with a kyphotic deformity that was mobile, rigid, or fixed. The mobile model achieved successive lordotic correction with each phase of correction. The rigid and fixed models achieved much less correction with no osteotomies and PCOs only, and the majority of correction with 3COs. Each model predicted with varying, but overall high, accuracy the amount of correction achieved in each patient. The surgeons felt the model had very high utility as a surgical education platform.

CONCLUSIONS

The models appeared to accurately replicate the gross anatomy and biomechanical performance of the patients' spines. This high fidelity to the individual patient's anatomy, bone quality, and segmental mobility resulted in a custom model that provides an invaluable learning platform for surgical education. These results suggest the models may have utility in surgical planning, but further studies are needed.

Pathological Features and Surgical Strategies of Cervical Deformity

Cervical deformity (CD) is a kind of disorder influencing cervical alignment. Although the incidence of CD is not high, this deformity can cause not only pain but also difficulties in daily activities such as swallowing and maintaining upright position. Even though the common cause of cervical deformity is still controversial, previous studies divided CD into congenital deformity and secondary deformity; secondary deformity includes iatrogenic and noniatrogenic deformity according to pathogenic factors. Due to the lack of relevant studies, a standardized evaluation for CD is absent. Even though the assessment of preoperative condition and surgical planning mainly rely on personal experience, the evaluation methods could still be summarized from previous studies. The objective in this article is to summarize studies on cervical scoliosis, identify clinical problems, and provide directions for researchers interested in delving deep into this specific topic. In this review, we found that the lack of standard classification system could lead to an absence of clinical guidance; in addition, the osseous landmarks and vascular distributions could be variable in CD patients, which might cause the risk of vascular or neurological complications; furthermore, multiple deformities were usually presented in CD patients, which might cause chain reaction after the correction of CD; this would prevent surgeons from choosing realignment surgery that is effective but risky.

The morphology of cervical deformities: a two-step cluster analysis to identify cervical deformity patterns

OBJECTIVE

Cervical deformity (CD) is difficult to define due to the high variability in normal cervical alignment based on postural- and thoracolumbar-driven changes to cervical alignment. The purpose of this study was to identify whether patterns of sagittal deformity could be established based on neutral and dynamic alignment, as shown on radiographs.

METHODS

This study is a retrospective review of a prospective, multicenter database of CD patients who underwent surgery from 2013 to 2015. Their radiographs were reviewed by 12 individuals using a consensus-based method to identify severe sagittal CD. Radiographic parameters correlating with health-related quality of life were introduced in a two-step cluster analysis (a combination of hierarchical cluster and k-means cluster) to identify patterns of sagittal deformity. A comparison of lateral and lateral extension radiographs between clusters was performed using an ANOVA in a post hoc analysis.

RESULTS

Overall, 75 patients were identified as having severe CD due to sagittal malalignment, and they formed the basis of this study. Their mean age was 64 years, their body mass index was 29 kg/m2, and 66% were female. There were significant correlations between focal alignment/flexibility of maximum kyphosis, cervical lordosis, and thoracic slope minus cervical lordosis (TS-CL) flexibility (r = 0.27, 0.31, and -0.36, respectively). Cluster analysis revealed 3 distinct groups based on alignment and flexibility. Group 1 (a pattern involving a flat neck with lack of compensation) had a large TS-CL mismatch despite flexibility in cervical lordosis; group 2 (a pattern involving focal deformity) had focal kyphosis between 2 adjacent levels but no large regional cervical kyphosis under the setting of a low T1 slope (T1S); and group 3 (a pattern involving a cervicothoracic deformity) had a very large T1S with a compensatory hyperlordosis of the cervical spine.

CONCLUSIONS

Three distinct patterns of CD were identified in this cohort: flat neck, focal deformity, and cervicothoracic deformity. One key element to understanding the difference between these groups was the alignment seen on extension radiographs. This information is a first step in developing a classification system that can guide the surgical treatment for CD and the choice of fusion level.

The Importance of C2 Slope, a Singular Marker of Cervical Deformity, Correlates With Patient-reported Outcomes

STUDY DESIGN

Retrospective review of a prospectively collected database.

OBJECTIVE

To define a simplified singular measure of cervical deformity (CD), C2 slope (C2S), which correlates with postoperative outcomes.

SUMMARY OF BACKGROUND DATA

Sagittal malalignment of the cervical spine, defined by the cervical sagittal vertical axis (cSVA) has been associated with poor outcomes following surgical correction of the deformity. There has been a proliferation of parameters to describe CD. This added complexity can lead to confusion in classifying, treating, and assessing outcomes of CD surgery.

METHODS

A prospective database of CD patients was analyzed. Inclusion criteria were cervical kyphosis>10°, cervical scoliosis>10°, cSVA>4 cm, or chin-brow vertical angle >25°. Patients were categorized into two groups and compared based on whether the apex of the deformity was in the cervical (C) or the cervicothoracic (CT) region. Radiographic parameters were correlated to C2S, T1 slope (T1S) and 1-year health-related quality-of-life outcomes as measured by the EuroQol 5 Dimension questionnaire (EQ5D), modified Japanese Orthopedic Association Scale, numeric rating scale for neck pain, and the Neck Disability Index (NDI).

RESULTS

One hundred four CD patients (C = 74, CT = 30; mean age 61 yr, 56% women, 42% revisions) were included. CT patients had higher baseline cSVA and T1S (P < 0.05). C2S correlated with T1 slope minus cervical lordosis (TS-CL) (r = 0.98, P < 0.001) and C0-C2 angle, cSVA, CL, T1S (r = 0.37-0.65, P < 0.001). Correlation of cSVA with C0-C2 was weaker (r = 0.48, P < 0.001). At 1-year postoperatively, higher C2S correlated with worse EQ-5D (r = 0.28, P = 0.02); in CT patients, higher C2S correlated with worse NDI, modified Japanese Orthopedic Association Scale, numeric rating scale for neck pain, and EQ5D (all r > 0.5, P≤0.05). Using linear regression, moderate disability by EQ5D corresponded to C2S of 20°(r = 0.08). For CT patients, C2S = 17° corresponded to moderate disability by NDI (r = 0.4), and C2S = 20° by EQ5D (r = 0.25).

CONCLUSION

C2S correlated with upper-cervical and subaxial alignment. C2S correlated strongly with TS-CL (R = 0.98, P < 0.001) because C2S is a mathematical approximation of TS-CL. C2S is a useful marker of CD, linking the occipitocervical and cervico-thoracic spine. C2S defines the presence of a mismatch between cervical lordosis and thoracolumbar alignment. Worse 1-year postoperative C2 slope correlated with worse health outcomes.

LEVEL OF EVIDENCE

3.

Predicting the combined occurrence of poor clinical and radiographic outcomes following cervical deformity corrective surgery

OBJECTIVE

Cervical deformity (CD) correction is clinically challenging. There is a high risk of developing complications with these highly complex procedures. The aim of this study was to use baseline demographic, clinical, and surgical factors to predict a poor outcome following CD surgery.

METHODS

The authors performed a retrospective review of a multicenter prospective CD database. CD was defined as at least one of the following: cervical kyphosis (C2-7 Cobb angle > 10°), cervical scoliosis (coronal Cobb angle > 10°), C2-7 sagittal vertical axis (cSVA) > 4 cm, or chin-brow vertical angle (CBVA) > 25°. Patients were categorized based on having an overall poor outcome or not. Health-related quality of life measures consisted of Neck Disability Index (NDI), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale scores. A poor outcome was defined as having all 3 of the following categories met: 1) radiographic poor outcome: deterioration or severe radiographic malalignment 1 year postoperatively for cSVA or T1 slope-cervical lordosis mismatch (TS-CL); 2) clinical poor outcome: failing to meet the minimum clinically important difference (MCID) for NDI or having a severe mJOA Ames modifier; and 3) complications/reoperation poor outcome: major complication, death, or reoperation for a complication other than infection. Univariate logistic regression followed by multivariate regression models was performed, and internal validation was performed by calculating the area under the curve (AUC).

RESULTS

In total, 89 patients with CD were included (mean age 61.9 years, female sex 65.2%, BMI 29.2 kg/m2). By 1 year postoperatively, 18 (20.2%) patients were characterized as having an overall poor outcome. For radiographic poor outcomes, patients' conditions either deteriorated or remained severe for TS-CL (73% of patients), cSVA (8%), horizontal gaze (34%), and global SVA (28%). For clinical poor outcomes, 80% and 60% of patients did not reach MCID for EQ-5D and NDI, respectively, and 24% of patients had severe symptoms (mJOA score 0-11). For the complications/reoperation poor outcome, 28 patients experienced a major complication, 11 underwent a reoperation, and 1 had a complication-related death. Of patients with a poor clinical outcome, 75% had a poor radiographic outcome; 35% of poor radiographic and 37% of poor clinical outcome patients had a major complication. A poor outcome was predicted by the following combination of factors: osteoporosis, baseline neurological status, use of a transition rod, number of posterior decompressions, baseline pelvic tilt, T2-12 kyphosis, TS-CL, C2-T3 SVA, C2-T1 pelvic angle (C2 slope), global SVA, and number of levels in maximum thoracic kyphosis. The final model predicting a poor outcome (AUC 86%) included the following: osteoporosis (OR 5.9, 95% CI 0.9-39), worse baseline neurological status (OR 11.4, 95% CI 1.8-70.8), baseline pelvic tilt > 20° (OR 0.92, 95% CI 0.85-0.98), > 9 levels in maximum thoracic kyphosis (OR 2.01, 95% CI 1.1-4.1), preoperative C2-T3 SVA > 5.4 cm (OR 1.01, 95% CI 0.9-1.1), and global SVA > 4 cm (OR 3.2, 95% CI 0.09-10.3).

CONCLUSIONS

Of all CD patients in this study, 20.2% had a poor overall outcome, defined by deterioration in radiographic and clinical outcomes, and a major complication. Additionally, 75% of patients with a poor clinical outcome also had a poor radiographic outcome. A poor overall outcome was most strongly predicted by severe baseline neurological deficit, global SVA > 4 cm, and including more of the thoracic maximal kyphosis in the construct.

Establishment of a novel rehabilitation program for patients with dropped head syndrome: Short and intensive rehabilitation (SHAiR) program

The pathophysiology of dropped head syndrome (DHS) remains unknown, and its treatment algorithm and indication are not standardized. Here, we established a novel rehabilitation program, short and intensive rehabilitation program for DHS (SHAiR program), consisting of cervical paraspinal muscles exercise, range of motion exercise, cervical and thoracic mobilization, deep cervical flexor muscle exercise, hip lift exercise, anterior pelvic tilt exercise, and walking exercise. The aim of this study was to evaluate the clinical effectiveness of this program. We reviewed clinical outcomes for five consecutive patients with DHS who underwent the SHAiR program (SHAiR group). The outcomes were compared with those of other five patients with DHS who received exercise instruction (control group). Demographic data, the duration from onset of DHS, the apex of sagittal kyphosis on the lateral radiographs, and clinical outcomes including the ability to maintain normal horizontal gaze, chin brow vertical angle, and numerical rating scale (NRS) were evaluated at the initial visit and final follow-up at 7.5 months. There was no significant difference between the two groups in terms of demographic and radiographic data. The ability of horizontal gaze and NRS of cervical pain improved rapidly for all five patients in the SHAiR group as compared to no improvement for all patients in the control group. Rehabilitation for DHS was considered effective not only for localized rehabilitation such as exercise for training cervical extensor muscle function but also exercises for thoracolumbar posture improvement and the psoas muscle.

Development of a Novel Cervical Deformity Surgical Invasiveness Index

STUDY DESIGN

Retrospective review.

OBJECTIVE

The aim of this study was to develop a novel surgical invasiveness index for cervical deformity (CD) surgery that incorporates CD-specific parameters.

SUMMARY OF BACKGROUND DATA

There has been a surgical invasiveness index for general spine surgery and adult spinal deformity, but a CD index has not been developed.

METHODS

CD was defined as at least one of the following: C2-C7 Cobb >10°, cervical lordosis (CL) >10°, cervical sagittal vertical axis (cSVA) >4 cm, chin brow vertical angle >25°. Consensus from experienced spine and neurosurgeons selected weightings for each variable that went into the invasiveness index. Binary logistic regression predicted high operative time (>338 minutes), estimated blood loss (EBL) (>600 mL), or length of stay (LOS) >5 days) based on the median values of operative time, EBL, and LOS. Multivariable regression modeling was utilized to construct a final model incorporating the strongest combination of factors to predict operative time, LOS, and EBL.

RESULTS

Eighty-five CD patients were included (61 years, 66% females). The variables in the newly developed CD invasiveness index with their corresponding weightings were: history of previous cervical surgery (3), anterior cervical discectomy and fusion (2/level), corpectomy (4/level), levels fused (1/level), implants (1/level), posterior decompression (2/level), Smith-Peterson osteotomy (2/level), three-column osteotomy (8/level), fusion to upper cervical spine (2), absolute change in T1 slope minus cervical lordosis, cSVA, T4-T12 thoracic kyphosis (TK), and sagittal vertical axis (SVA) from baseline to 1-year. The newly developed CD-specific invasiveness index strongly predicted long LOS (R = 0.310, P < 0.001), high EBL (R = 0.170, P = 0.011), and extended operative time (R = 0.207, P = 0.031). A second analysis used multivariable regression modeling to determine which combination of factors in the newly developed index were the strongest determinants of operative time, LOS, and EBL. The final predictive model included: number of corpectomies, levels fused, decompression, combined approach, and absolute changes in SVA, cSVA, and TK. This model predicted EBL (R = 0.26), operative time (R = 0.12), and LOS (R = 0.13).

CONCLUSION

Extended LOS, operative time, and high blood loss were strongly predicted by the newly developed CD invasiveness index, incorporating surgical factors and radiographic parameters clinically relevant for patients undergoing CD corrective surgery.

LEVEL OF EVIDENCE

4.

Perioperative complications with multilevel anterior and posterior cervical decompression and fusion

OBJECTIVE

Cervical spondylotic myelopathy (CSM) is a progressive degenerative pathology that frequently affects older individuals and causes spinal cord compression with symptoms of neck pain, radiculopathy, and weakness. Anterior decompression and fusion is the primary intervention to prevent neurological deterioration; however, in severe cases, circumferential decompression and fusion is necessary. Published data regarding perioperative morbidity associated with these complex operations are scarce. In this study, the authors sought to add to this important body of literature by documenting a large single-surgeon experience of single-session circumferential cervical decompression and fusion.

METHODS

A retrospective analysis was performed to identify intended single-stage anterior-posterior or posterior-anterior-posterior cervical spine decompression and fusion surgeries performed by the primary surgeon (V.C.T.) at Rush University Medical Center between 2009 and 2016. Cases in which true anterior-posterior cervical decompression and fusion was not performed (i.e., those involving anterior-only, posterior-only, or delayed circumferential fusion) were excluded from analysis. Data including standard patient demographic information, comorbidities, previous surgeries, and intraoperative course, along with postoperative outcomes and complications, were collected and analyzed. Perioperative morbidity was recorded during the 90 days following surgery.

RESULTS

Seventy-two patients (29 male and 43 female, mean age 57.6 years) were included in the study. Fourteen patients (19.4%) were active smokers, and 56.9% had hypertension, the most common comorbidity. The most common clinical presentation was neck pain in 57 patients (79.2%). Twenty-three patients (31.9%) had myelopathy, and 32 patients (44.4%) had undergone prior cervical spine surgery. Average blood loss was 613 ml. Injury to the vertebral artery was encountered in 1 patient (1.4%). Recurrent laryngeal nerve palsy was observed in 2 patients (2.8%). Two patients (2.8%) had transient unilateral hand grip weakness. There were no permanent neurological deficits. Dysphagia was encountered in 45 patients (62.5%) postoperatively, with 23 (32%) requiring nasogastric parenteral nutrition and 9 (12.5%) patients ultimately undergoing percutaneous endoscopic gastrostomy (PEG) placement. Nine of the 72 patients required a tracheostomy. The incidence of pneumonia was 6.9% (5 patients) overall, and 2 of these patients were in the tracheostomy group. Superficial wound infections occurred in 4 patients (5.6%). Perioperative death occurred in 1 patient. Reoperation was necessary in 10 patients (13.9%). Major perioperative complications (permanent neurological deficit, vascular injury, tracheostomy, PEG tube, stroke, or death) occurred in 30.6% of patients. The risk of minor perioperative complications (temporary deficit, dysphagia, deep vein thrombosis, pulmonary embolism, urinary tract infection, pneumonia, or wound infection) was 80.6%.

CONCLUSIONS

Single-session anterior-posterior cervical decompression and fusion is an inherently morbid operation required in select patients with cervical spondylotic myelopathy. In this large single-surgeon series, there was a major perioperative complication risk of 30.6% and minor perioperative complication risk of 80.6%. This overall elevated risk for postoperative complications must be carefully considered and discussed with the patient preoperatively. In some situations, shared decision making may lead to the conclusion that a procedure of lesser magnitude may be more appropriate.

Prospective Multicenter Assessment of All-Cause Mortality Following Surgery for Adult Cervical Deformity

BACKGROUND

Surgical treatments for adult cervical spinal deformity (ACSD) are often complex and have high complication rates.

OBJECTIVE

To assess all-cause mortality following ACSD surgery.

METHODS

ACSD patients presenting for surgical treatment were identified from a prospectively collected multicenter database. Clinical and surgical parameters and all-cause mortality were assessed.

RESULTS

Of 123 ACSD patients, 120 (98%) had complete baseline data (mean age, 60.6 yr). The mean number of comorbidities per patient was 1.80, and 80% had at least 1 comorbidity. Surgical approaches included anterior only (15.8%), posterior only (50.0%), and combined anterior/posterior (34.2%). The mean number of vertebral levels fused was 8.0 (standard deviation [SD] = 4.5), and 23.3% had a 3-column osteotomy. Death was reported for 11 (9.2%) patients at a mean of 1.1 yr (SD = 0.76 yr; range = 7 d to 2 yr). Mean follow-up for living patients was 1.2 yr (SD = 0.64 yr). Causes of death included myocardial infarction (n = 2), pneumonia/cardiopulmonary failure (n = 2), sepsis (n = 1), obstructive sleep apnea/narcotics (n = 1), subsequently diagnosed amyotrophic lateral sclerosis (n = 1), burn injury related to home supplemental oxygen (n = 1), and unknown (n = 3). Deceased patients did not significantly differ from alive patients based on demographic, clinical, or surgical parameters assessed, except for a higher major complication rate (excluding mortality; 63.6% vs 22.0%, P = .006).

CONCLUSION

All-cause mortality at a mean of 1.2 yr following surgery for ACSD was 9.2% in this prospective multicenter series. Causes of death were reflective of the overall high level of comorbidities. These findings may prove useful for treatment decision making and patient counseling in the context of the substantial impact of ACSD.

Predicting the Occurrence of Postoperative Distal Junctional Kyphosis in Cervical Deformity Patients

BACKGROUND

Distal junctional kyphosis (DJK) development after cervical deformity (CD)-corrective surgery is a growing concern for surgeons and patients. Few studies have investigated risk factors that predict the occurrence of DJK.

OBJECTIVE

To predict DJK development after CD surgery using predictive modeling.

METHODS

CD criteria was at least one of the following: C2-C7 Coronal/Cobb &gt; 10°, C2-7 sagittal vertical axis (cSVA) &gt; 4 cm, chin-brow vertical angle &gt; 25°. DJK was defined as the development of an angle &lt;−10° from the end of fusion construct to the second distal vertebra, and change in this angle by &lt;−10° from baseline to postoperative. Baseline demographic, clinical, and surgical information were used to predict the occurrence of DJK using generalized linear modeling both as one overall model and as submodels using baseline demographic and clinical predictors or surgical predictors.

RESULTS

One hundred seventeen CD patients were included. At any postoperative visit up to 1 yr, 23.1% of CD patients developed DJK. DJK was predicted with high accuracy using a combination of baseline demographic, clinical, and surgical factors by the following factors: preoperative neurological deficit, use of transition rod, C2-C7 lordosis (CL)&lt;−12°, T1 slope minus CL &gt; 31°, and cSVA &gt; 54 mm. In the model using only baseline demographic/clinical predictors of DJK, presence of comorbidities, presence of baseline neurological deficit, and high preoperative C2-T3 angle were included in the final model (area under the curve = 87%). The final model using only surgical predictors for DJK included combined approach, posterior upper instrumented vertebrae below C4, use of transition rod, lack of anterior corpectomy, more than 3 posterior osteotomies, and performance of a 3-column osteotomy.

CONCLUSION

Preoperative assessment and consideration should be given to these factors that are predictive of DJK to mitigate poor outcomes.

McGregor's slope and slope of line of sight: two surrogate markers for Chin-Brow vertical angle in the setting of cervical spine pathology

BACKGROUND CONTEXT

Chin-Brow Vertical Angle (CBVA) is not routinely measured on radiographs even though it is a strong assessor of horizontal gaze.

STUDY DESIGN

Retrospective cohort study of patients with full-body stereoradiographs and a primary cervical diagnosis at the time of presentation.

PURPOSE

Assess the utility of McGregor's Slope (McGS) and Slope of Line of Sight (SLS) as surrogate markers for the CBVA in cervical spine pathology.

METHODS

A retrospective review of patients with full-body stereoradiographs was performed. Patients were ≥18 years of age with a primary cervical diagnosis. Analysis of CBVA, McGS, and SLS was conducted as markers of horizontal gaze. Sagittal alignment was characterized by: pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), T1-pelvic angle (TPA), sagittal vertical axis (SVA), T2-T12 thoracic kyphosis, C2-C7 SVA (cSVA), C2-C7 Cervical lordosis, T1-Slope minus Cervical Lordosis (TS-CL), and C2-Slope (C2S). A subgroup analysis was performed in patients with cervical deformity. Independent sample t tests and paired t tests compared radiographic alignment. Pearson correlations characterized linear relationships. Linear regression analysis identified relationships between the parameters.

RESULTS

In all, 329 patients were identified with primary cervical spine diagnoses. Chin-Brow Vertical Angle was visible in 171 patients (52.0%), McGS in 281 (85.4%), and SLS in 259 (78.7%). Of the 171 patients with visible CBVA, the mean CBVA was 2.30±7.7, mean McGS was 5.02±8.1, and mean SLS was -1.588±2.03. Chin-Brow Vertical Angle strongly correlated with McGS (r=0.83) and SLS (r=0.89) with p<.001. McGregor's Slope positively correlated with SLS (r=0.89, p=.001).

CONCLUSIONS

This study demonstrates that McGS and SLS serve as strong, positive correlates for CBVA. The reported mean differences between these measurements provide a useful conversion, broadening CBVA's use as a radiographic assessment of horizontal gaze.

Predicting extended operative time and length of inpatient stay in cervical deformity corrective surgery

It's increasingly common for surgeons to operate on more challenging cases and higher risk patients, resulting in longer op-time and inpatient LOS. Factors predicting extended op-time and LOS for cervical deformity (CD) patients are understudied. This study identified predictors of extended op-time and length of stay (LOS) after CD-corrective surgery. CD patients with baseline (BL) radiographic data were included. Patients were stratified by extended LOS (ELOS; >75th percentile) and normal LOS (N-LOS; <75th percentile). Op-time analysis excluded staged cases, cases >12 h. A Conditional Variable Importance Table used non-replacement sampling set of Conditional Inference trees to identify influential factors. Mean comparison tests compared LOS and op-time for top factors. 142 surgical CD patients (61 yrs, 62%F, 8.2 levels fused). Op-time and LOS were 358 min and 7.2 days; 30% of patients experienced E-LOS (14 ± 13 days). Overlapping predictors of E-LOS and op-time included levels fused (>7 increased LOS 2.7 days; >5 increased op-time 96 min, P < 0.001), approach (anterior reduced LOS 3.0 days; combined increased op-time 69 min, P < 0.01), BMI (>38 kg/m² increased LOS 8.1 days; >39 kg/m² increased op-time 17 min), and osteotomy (LOS 2.0 days, op-time 62 min, P < 0.005). BL cervical parameters increased LOS and op-time: cSVA (>42 mm increased LOS; >50 mm increased op-time, P < 0.030), C0 slope (>@-0.9° increased LOS, >0.3° increased op-time, P < 0.003.) Additional op-time predictors: prior cervical surgery (p = 0.004) and comorbidities (P = 0.015). Other predictors of E-LOS: EBL (P < 0.001), change in mental status (P = 0.001). Baseline cervical malalignment, levels fused, and osteotomy predicted both increased op-time and LOS. These results can be used to better optimize patient care, hospital efficiency, and resource allocation.

Limited morbidity and possible radiographic benefit of C2 vs. subaxial cervical upper-most instrumented vertebrae

Background

The study aims to evaluate differences in alignment and clinical outcomes between surgical cervical deformity (CD) patients with a subaxial upper-most instrumented vertebra (UIV) and patients with a UIV at C2. Use of CD-corrective instrumentation in the subaxial cervical spine is considered risky due to narrow subaxial pedicles and vertebral artery anatomy. While C2 fixation provides increased stability, the literature lacks guidelines indicating extension of CD-corrective fusion from the subaxial spine to C2.

Methods

Included: operative CD patients with baseline (BL) and 1-year postop (1Y) radiographic data, cervical UIV ≥ C2. Patients were grouped by UIV: C2 or subaxial (C3-C7) and propensity score matched (PSM) for BL cSVA. Mean comparison tests assessed differences in BL and 1Y patient-related, radiographic, and surgical data between UIV groups, and BL-1Y changes in alignment and clinical outcomes.

Results

Following PSM, 31 C2 UIV and 31 subaxial UIV patients undergoing CD-corrective surgery were included. Groups did not differ in BL comorbidity burden (P=0.175) or cSVA (P=0.401). C2 patients were older (64 vs. 58 yrs, P=0.010) and had longer fusions (9 vs. 6 levels, P=0.002). Overall, patients showed BL-1Y improvements in TS-CL (P<0.001), cSVA (P=0.005), McGS (P=0.004). Cervical flexibility was maintained at 1Y regardless of UIV, assessed by CL flexion (-0.2° vs. 6.0°, P=0.115) and extension (13.9° vs. 9.9°, P=0.366). While both subaxial and C2 patients showed BL-1Y improvements in McGS (both P<0.030), C2 patients improved to a larger degree (7.3° vs. 6.2°). Between UIV groups, there were no differences in BL-1Y changes in HRQLs, overall complication rates, or operative complication rates (all P>0.05).

Conclusions

C2 UIV patients showed similar cervical range of motion and baseline to 1-year functional outcomes as patients with a subaxial UIV. C2 UIV patients also showed greater baseline to 1-year horizontal gaze improvement and had complication profiles similar to subaxial UIV patients, demonstrating the radiographic benefit and minimal functional loss associated with extending fusion constructs to C2. In the treatment of adult cervical deformities, extension of the reconstruction construct to the axis may allow for certain clinical benefits with less morbidity than previously acknowledged.

Adult cervical deformity: radiographic and osteotomy classifications

Cervical spine deformity represents a broad spectrum of pathologies that are both complex in etiology and debilitating towards quality of life for patients. Despite advances in the understanding of drivers and outcomes of cervical spine deformity, only one classification system and one system of nomenclature for osteotomy techniques currently exist. Moreover, there is a lack of standardization regarding the indications for each technique. This article reviews the adult cervical deformity (ACD) and current classification and nomenclature for osteotomy techniques, highlighting the need for further work to develop a unified approach for each case and improve communication amongst the spine community with respect to ACD.

Grading of Complications After Cervical Deformity-corrective Surgery: Are Existing Classification Systems Applicable?

STUDY DESIGN

This is a retrospective review of prospective multicenter cervical deformity (CD) database.

OBJECTIVE

Assess the impact of complication type and Clavien complication (Cc) grade on clinical outcomes of surgical CD patients BACKGROUND:: Validated for general surgery, the Clavien-Dindo complication classification system allows for broad comparison of postoperative complications; however, the applicability of this system is unclear in CD-specific populations.

METHODS

Surgical CD patients above 18 years with baseline and postoperative clinical data were included. Primary outcomes were complication type (renal, infection, cardiac, pulmonary, gastrointestinal, neurological, musculoskeletal, implant-related, radiographic, operative, wound) and Cc grade (I, II, III, IV, V). Secondary outcomes were estimated blood loss (EBL), length of stay (LOS), reoperation, and health-related quality of life (HRQL) score. The univariate analysis assessed the impact of complication type and Cc grade on improvement markers and 1-year postoperative HRQL outcomes.

RESULTS

In total, 153 patients (61±10 y, 61% female) underwent surgery for CD (8.1±4.6 levels fused; surgical approach included 48% posterior, 18% anterior, 34% combined). Overall, 63% of patients suffered at least 1 complication. Complication breakdown by type: renal (2.0%), infection (5.2%), cardiac (7.2%), pulmonary (3.9%), gastrointestinal (2.0%), neurological (26.1%), musculoskeletal (0.0%), implant-related (3.9%), radiographic (16.3%), operative (7.8%), and wound (5.2%). Of complication types, only operative complications were associated with increased EBL (P=0.004), whereas renal, cardiac, pulmonary, gastrointestinal, neurological, radiographic, and wound infections were associated with increased LOS (P<0.050). Patients were also assessed by Cc grade: I (28%), II (14.3%), III (16.3%), IV (6.5%), and V (0.7%). Grades I and V were associated with increased EBL (both P<0.050); Cc grade V was the only complication not associated with increased LOS (P=0.610). Increasing complication severity was correlated with increased risk of reoperation (r=0.512; P<0.001), but not inferior 1-year HRQL outcomes (all P>0.05).

CONCLUSIONS

Increasing complication severity, assessed by the Clavien-Dindo classification system, was not associated with increased EBL, inpatient LOS, or inferior 1-year postoperative HRQL outcomes. Only operative complications were associated with increased EBL. These results suggest a need for modification of the Clavien system to increase applicability and utility in CD-specific populations.

Cervical Spine Deformity: Indications, Considerations, and Surgical Outcomes

Cervical spinal deformity (CSD) in adult patients is a relatively uncommon yet debilitating condition with diverse etiologies and clinical manifestations. Similar to thoracolumbar deformity, CSD can be broadly divided into scoliosis and kyphosis. Severe forms of CSD can lead to pain; neurologic deterioration, including myelopathy; and cervical spine-specific symptoms such as difficulty with horizontal gaze, dysphagia, and dyspnea. Recently, an increased interest is shown in systematically studying CSD with introduction of classification schemes and treatment algorithms. Both major and minor complications after surgical intervention have been analyzed and juxtaposed to patient-reported outcomes. An ongoing effort exists to better understand the relationship between cervical and thoracolumbar spinal alignment, most importantly in the sagittal plane.

Comparison of Best Versus Worst Clinical Outcomes for Adult Cervical Deformity Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Factors that predict outcomes for adult cervical spine deformity (ACSD) have not been well defined. To compare ACSD patients with best versus worst outcomes.

METHODS

This study was based on a prospective, multicenter observational ACSD cohort. Best versus worst outcomes were compared based on Neck Disability Index (NDI), Neck Pain Numeric Rating Scale (NP-NRS), and modified Japanese Orthopaedic Association (mJOA) scores.

RESULTS

Of 111 patients, 80 (72%) had minimum 1-year follow-up. For NDI, compared with best outcome patients (n = 28), worst outcome patients (n = 32) were more likely to have had a major complication (P = .004) and to have undergone a posterior-only procedure (P = .039), had greater Charlson Comorbidity Index (P = .009), and had worse postoperative C7-S1 sagittal vertical axis (SVA; P = .027). For NP-NRS, compared with best outcome patients (n = 26), worst outcome patients (n = 18) were younger (P = .045), had worse baseline NP-NRS (P = .034), and were more likely to have had a minor complication (P = .030). For the mJOA, compared with best outcome patients (n = 16), worst outcome patients (n = 18) were more likely to have had a major complication (P = .007) and to have a better baseline mJOA (P = .030). Multivariate models for NDI included posterior-only surgery (P = .006), major complication (P = .002), and postoperative C7-S1 SVA (P = .012); models for NP-NRS included baseline NP-NRS (P = .009), age (P = .017), and posterior-only surgery (P = .038); and models for mJOA included major complication (P = .008).

CONCLUSIONS

Factors distinguishing best and worst ACSD surgery outcomes included patient, surgical, and radiographic factors. These findings suggest areas that may warrant greater awareness to optimize patient counseling and outcomes.

Cervical Kyphotic Deformity Worsening After Extensor Cervical Muscle Paralysis from Botulinum Toxin Injection

BACKGROUND

Botulinum toxin (Botox) has long been used therapeutically to treat a variety of diseases, including migraine headaches, cervical spine dystonia, and chronic cervical spine pain, among many others. Although quite useful, Botox has been reported to cause adverse events, some of which may lead to devastating morbidity.

CASE DESCRIPTION

An elderly woman presented with severe neck pain after a motor vehicle collision. She underwent Botox administration to the neck extensor muscles, after which she developed severe cervical kyphotic deformity, a complication previously reported only in patients with a history of cervical fusion. In addition, the patient had a pre-existing cervical spine degenerative disc disease with listhesis resulting in cervical kyphotic deformity and loss of cervical lordosis.

CONCLUSIONS

This case illustrates a potential danger of using Botox in the neck of an elderly patient who may have pre-existing cervical spine instability, underlying cervical musculature weakness, and pre-existing cervical kyphosis. It demonstrates the need to evaluate patients who are predisposed to developing cervical kyphotic deformities before offering them Botox treatment.

Zero-profile Hyperlordotic Spacer for Cervical Deformity Correction: Case Presentation and Technical Note

Cervical spine deformity (CSD) can negatively affect the health-related quality of life (HRQOL) of patients, particularly the elderly, thus representing a socioeconomic problem of increasing importance. While surgical deformity correction has been linked to improved HRQOL, no universally accepted consensus exists for the operative management of CSD.

The authors demonstrate the feasibility of CSD correction, implementing anterior and posterior cervical osteotomies combined with the placement of multiple consecutive zero-profile hyperlordotic interbody spacers in a 55-year-old male with cervical kyphosis. This technique resulted in the satisfactory restoration of the patient’s cervical alignment and significantly ameliorated his presenting symptoms. The patient demonstrated maintained cervical lordosis and he remained symptom-free at the one-year follow-up.

The use of multiple consecutive zero-profile cervical interbody spacers can effectively and safely be utilized for the treatment of CSD. Further studies are needed to compare this technique with other standard surgeries used for CSD correction.

The impact of osteotomy grade and location on regional and global alignment following cervical deformity surgery

Introduction:

Correction of cervical deformity (CD) often involves different types of osteotomies to address sagittal malalignment. This study assessed the relationship between osteotomy grade and vertebral level on alignment and clinical outcomes.

Methods:

Retrospective review of a multi-center prospectively collected CD database. CD was defined as at least one of the following: C2–C7 Cobb >10°, cervical lordosis (CL) >10°, C2–C7 sagittal vertical axis (cSVA) >4 cm, and chin-brow vertical angle > 25°. Patients were evaluated for level and type of cervical osteotomy.

Results:

86 CD patients were included (61.4 ± 10.6 years, 66.3% female, body mass index 29.1 kg/m²). 141 osteotomies were in the cervical spine and 79 were in the thoracic spine. There were 19 major osteotomies performed, with 47% at T1. Patients with an osteotomy in the cervical spine improved in T1 slope minus CL (TS − CL), CL, and C2 slope (all P < 0.05). Patients with upper thoracic osteotomies improved in TS − CL, cSVA, C2–T3, C2–T3 sagittal vertical axis (SVA), and C2 slope (all P < 0.05). Minor osteotomies in the upper thoracic spine showed improvement in cSVA (63 mm to 49 mm, P = 0.022), C2–T3 (P = 0.007), and SVA (−16 mm to 27 mm, P < 0.001). The greatest amount of C2–T3 angular change occurred for patients with a major osteotomy at T2 (39.1° change), then T3 (15.7°), C7 (16.9°°), and T1 (13.5°°). Patients with a major osteotomy in the upper thoracic spine showed similar radiographic changes from pre- to post-operative as patients with three or more minor osteotomies, although C2–T3 SVA trended toward greater improvement with a major osteotomy (−22.5 mm vs. +5.9 mm, P = 0.058) due to lever arm effect.

Conclusions:

CD patients undergoing osteotomies in the cervical and upper thoracic spine experienced improvement in TS–−CL and C2 slope. In the upper thoracic spine, multiple minor osteotomies achieved similar alignment changes to major osteotomies at a single level, while a major osteotomy focused at T2 had the greatest overall impact in cervicothoracic and global alignment in CD patients.

Use of an Articulating Hinge to Facilitate Cervicothoracic Deformity Correction During Vertebral Column Resection

BACKGROUND

Surgical treatment of severe cervicothoracic kyphotic deformity may require the use of 3-column osteotomies such as the pedicle subtraction osteotomy and vertebral column resection (VCR), or VCR with anterior longitudinal ligament resection. Such procedures are extensive and are associated with high intra- and perioperative morbidity, in part, due to the need for risky reduction maneuvers.

OBJECTIVE

To describe a novel technique utilizing a laterally placed articulating hinge to facilitate kyphotic deformity correction of the cervicothoracic spine.

METHODS

A patient with severe chin-on-chest deformity of the cervicothoracic spine presented for evaluation and a 2-stage VCR with anterior longitudinal ligament resection was planned. To reduce the risk of intraoperative neurological injury and for increased control during reduction maneuvers, lateral instrumentation was placed through the chest wall resection above and below the level of VCR, which was adjoined with an articulating hinge rod apparatus.

RESULTS

Satisfactory reduction of the kyphosis was achieved utilizing the hinge rod apparatus for controlled deformity correction. The patient remained neurologically intact following this procedure with improvement in their spinal alignment.

CONCLUSION

We present a novel technique utilizing a lateral hinge rod apparatus for efficient, controlled correction of severe kyphotic deformity.

The Relationship Between Improvements in Myelopathy and Sagittal Realignment in Cervical Deformity Surgery Outcomes

STUDY DESIGN

Retrospective review.

OBJECTIVE

Determine whether alignment or myelopathy improvement drives patient outcomes after cervical deformity (CD) corrective surgery.

SUMMARY OF BACKGROUND DATA

CD correction involves radiographic malalignment correction and procedures to improve motor function and pain. It is unknown whether alignment or myelopathy improvement drives patient outcomes.

METHODS

Inclusion: Patients with CD with baseline/1-year radiographic and outcome scores. Cervical alignment improvement was defined by improvement in Ames CD modifiers. modified Japanese Orthopaedic Association (mJOA) improvement was defined as mild [15-17], moderate [12-14], severe [<12]. Patient groups included those who only improved in alignment, those who only improved in mJOA, those who improved in both, and those who did not improve. Changes in quality-of-life scores (neck disability index [NDI], EuroQuol-5 dimensions [EQ-5D], mJOA) were evaluated between groups.

RESULTS

A total of 70 patients (62 yr, 51% F) were included. Overall preoperative mJOA score was 13.04 ± 2.35. At baseline, 21 (30%) patients had mild myelopathy, 33 (47%) moderate, and 16 (23%) severe. Out of 70 patients 30 (44%) improved in mJOA and 13 (18.6%) met 1-year mJOA minimal clinically important difference. Distribution of improvement groups: 16/70 (23%) alignment-only improvement, 13 (19%) myelopathy-only improvement, 18 (26%) alignment and myelopathy improvement, and 23 (33%) no improvement. EQ-5D improved in 11 of 16 (69%) alignment-only patients, 11 of 18 (61%) myelopathy/alignment improvement, 13 of 13 (100%) myelopathy-only, and 10 of 23 (44%) no myelopathy/alignment improvement. There were no differences in decompression, baseline alignment, mJOA, EQ-5D, or NDI between groups. Patients who improved only in myelopathy showed significant differences in baseline-1Y EQ-5D (baseline: 0.74, 1 yr:0.83, P < 0.001). One-year C2-S1 sagittal vertical axis (SVA; mJOA r = -0.424, P = 0.002; EQ-5D r = -0.261, P = 0.050; NDI r = 0.321, P = 0.015) and C7-S1 SVA (mJOA r = -0.494, P < 0.001; EQ-5D r = -0.284, P = 0.031; NDI r = 0.334, P = 0.010) were correlated with improvement in health-related qualities of life.

CONCLUSION

After CD-corrective surgery, improvements in myelopathy symptoms and functional score were associated with superior 1-year patient-reported outcomes. Although there were no relationships between cervical-specific sagittal parameters and patient outcomes, global parameters of C2-S1 SVA and C7-S1 SVA showed significant correlations with overall 1-year mJOA, EQ-5D, and NDI. These results highlight myelopathy improvement as a key driver of patient-reported outcomes, and confirm the importance of sagittal alignment in patients with CD.

LEVEL OF EVIDENCE

3.