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

Outcomes and survival analysis of adult cervical deformity patients with 10-year follow-up

BACKGROUND

Previous studies have demonstrated that adult cervical deformity patients may be at increased risk of death in conjunction with increased frailty or a weakened physiologic state. However, such studies have often been limited by follow-up duration, and longer-term studies are needed to better assess temporal changes in ACD patients and associated mortality risk.

PURPOSE

To assess if patients with decreased comorbidities and physiologic burden will be at lessened risk of death for a greater length of time after undergoing adult cervical deformity surgery.

STUDY DESIGN/SETTING

Retrospective review.

PATIENT SAMPLE

Two hundred ninety ACD patients.

OUTCOME MEASURES

Morbidity and mortality data.

METHODS

Operative ACD patients ≥18 years with pre-(BL) and 10-year (10Y) data were included. Patients were stratified as expired versus living, as well as temporally grouped by Expiration prior to 5Y or between 5Y and 10Y. Group differences were assessed via means comparison analysis. Backstep logistic regression identified mortality predictors. Kaplan-Meier analysis assessed survivorship of expired patients. Log rank analysis determined differences in survival distribution groups.

RESULTS

Sixty-six total patients were included (60.97±10.19 years, 48% female, 28.03±7.28 kg/m2). Within 10Y, 12 (18.2% of ACD cohort) expired. At baseline, patients were comparable in age, gender, BMI, and CCI total on average (all p>.05). Furthermore, patients were comparable in BL HRQLs (all p>.05). However, patients who expired between 5Y and 10Y demonstrated higher BL EQ5D and mJOA scores than their earlier expired counterparts at 2Y (p<.021). Furthermore, patients who presented with no CCI markers at BL were significantly more likely to survive until the 5Y-10Y follow-up window. Surgically, the only differences observed between patients who survived until 5Y was in undergoing osteotomy, with longer survival seen in those who did not require it (p=.003). Logistic regression revealed independent predictors of death prior to 5Y to be increased BMI, increased frailty, and increased levels fused (model p<.001). KM analysis found that by Passias et al frailty, not frail patients had mean survival time of 170.56 weeks, versus 158.00 in frail patients (p=.949).

CONCLUSIONS

Our study demonstrates that long-term survival after cervical deformity surgery may be predicted by baseline surgical factors. By optimizing BMI, frailty status, and minimizing fusion length when appropriate, surgeons may be able to further assist ACD patients in increasing their survivability postoperatively.

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.

A Hierarchical Approach to Realignment Strategies in Adult Cervical Deformity Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Construct an individualized cervical realignment strategy based on patient parameters at the presentation that results in superior 2-year health-related quality of life metrics and decreased rates of junctional failure and reoperation following adult cervical deformity surgery.

SUMMARY OF BACKGROUND DATA

Research has previously focused on adult cervical deformity realignment thresholds for maximizing clinical outcomes while minimizing complications. However, realignment strategies may differ based on patient presentation and clinical characteristics.

METHODS

We included adult cervical deformity patients with 2-year data. The optimal outcome was defined as meeting good clinical outcomes without distal junctional failure or reoperation. Radiographic parameters assessed included C2 Slope, C2-C7, McGregor's slope, TS-CL, cSVA, T1 slope, and preoperative lowest-instrumented vertebra (LIV) inclination angle. Conditional inference trees were used to establish thresholds for each parameter based on achieving the optimal outcome. Analysis of Covariance and multivariable logistic regression analysis, controlling for age, comorbidities, baseline deformity and disability, and surgical factors, assessed outcome rates for the hierarchical approach within each deformity group.

RESULTS

One hundred twenty-seven patients were included. After correction, there was a significant difference in meeting the optimal outcome when correcting the C2 slope below 10 degrees (85% vs. 34%, P <0.001), along with lower rates of distal junctional failure (DJF) (7% vs. 42%, P <0.001). Next, after isolating patients below the C2 slope threshold, the selection of LIV with an inclination between 0 and 40 degrees demonstrated lower rates of distal junctional kyphosis and higher odds of meeting optimal outcome(OR: 4.2, P =0.011). The best third step was the correction of cSVA below 35 mm. This hierarchical approach (11% of the cohort) led to significantly lower rates of DJF (0% vs. 15%, P <0.007), reoperation (8% vs. 28%, P <0.001), and higher rates of meeting optimal outcome (93% vs. 36%, P <0.001) when controlling for age, comorbidities, and baseline deformity and disability.

CONCLUSION

Our results indicate that the correction of C2 slope should be prioritized during cervical deformity surgery, with the selection of a stable LIV and correction of cervical SVA below the idealized threshold. Among the numerous radiographic parameters considered during preoperative planning for cervical deformity correction, our determinations help surgeons prioritize those realignment strategies that maximize the health-related quality of life outcomes and minimize complications.

LEVEL OF EVIDENCE

Level-III.

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.

Resting-state functional MRI language network connectivity differences in patients with brain tumors: exploration of the cerebellum and contralesional hemisphere

Brain tumors can have far-reaching impacts on functional networks. Language processing is typically lateralized to the left hemisphere, but also involves the right hemisphere and cerebellum. This resting-state functional MRI study investigated the proximal and distal effects of left-hemispheric brain tumors on language network connectivity in the ipsilesional and contralesional hemispheres. Separate language resting-state networks were generated from seeding in ipsilesional (left) and contralesional (right) Broca's Area for 29 patients with left-hemispheric brain tumors and 13 controls. Inclusion criteria for all subjects included language left-dominance based on task-based functional MRI. Functional connectivity was analyzed in each network to the respective Wernicke's Area and contralateral cerebellum. Patients were assessed for language deficits prior to scanning. Compared to controls, patients exhibited decreased connectivity in the ipsilesional and contralesional hemispheres between the Broca's Area and Wernicke's Area homologs (mean connectivity for patients/controls: left 0.51/0.59, p < 0.002; right 0.52/0.59, p < 0.0002). No differences in mean connectivity to the contralateral cerebellum were observed between groups (p > 0.09). Crossed cerebro-cerebellar connectivity was correlated in controls (rho = 0.59, p < 0.05), patients without language deficits (rho = 0.74, p < 0.0002), and patients with high-grade gliomas (rho = 0.78, p < 0.0002), but not in patients with language deficits or low-grade gliomas (p > 0.l). These findings demonstrate that brain tumors impact the language network in the contralesional hemisphere and cerebellum, which may reflect neurological deficits and lesion-induced cortical reorganization.

Etiology and treatment of cervical kyphosis: state of the art review-a narrative review

Objective

To provide state of the art review regarding cervical kyphosis.

Background

Cervical spine kyphosis has been increasingly common due to the growing elderly population. Clinicians should comprehensively understand its symptoms, biomechanics, etiology, radiographic evaluation, classification, and treatment options and complications of each treatment. Comprehensive review will help clinicians improve the management for patients with cervical kyphosis.

Methods

The available literature relevant to cervical kyphosis was reviewed. PubMed, Medline, OVID, EMBASE, and Cochrane were used to review the literature.

Conclusions

This article summarizes current concepts regarding etiology, evaluation, surgical treatment, complications and outcomes of cervical kyphosis. Major etiologies of cervical kyphosis include degenerative, post-laminectomy, and ankylosing spondylitis. Clinical presentations include neck pain, myelopathy, radiculopathy, and problems with horizontal gaze, swallowing and breathing. Cervical lordosis, C2-7 sagittal vertical axis, chin-brow to vertical angle, and T1 slope should be evaluated from upright lateral 36-inch film. The most widely used classification system includes a deformity descriptor and 5 modifiers. A deformity descriptor provides a basic grouping of the deformity consisting of five types, cervical, cervicothoracic, thoracic, coronal cervical deformity, and cranio-vertebral junction deformity. The 5 modifiers include C2-7 sagittal vertical axis, chin-brow to vertical angle, T1 slope minus cervical lordosis, myelopathy based on modified Japanese Orthopaedic Association score, and SRS-Schwab classification for thoracolumbar deformity. Current treatment options include anterior discectomy and fusion, anterior osteotomy, Smith-Peterson osteotomy, pedicle subtraction osteotomy, or a combination of these based on careful preoperative evaluation.

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.

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.

Surgical Strategies for Cervical Deformities Associated With Neuromuscular Disorders

Neuromuscular disorders (NMDs) are diseases involving the upper and lower motor neurons and muscles. In patients with NMDs, cervical spinal deformities are a very common issue; however, unlike thoracolumbar spinal deformities, few studies have investigated these disorders. The patients with NMDs have irregular spinal curvature caused by poor balance and poor coordination of their head, neck, and trunk. Particularly, cervical deformity occurs at younger age, and is known to show more rigid and severe curvature at high cervical levels. Muscular physiologic dynamic characteristics such as spasticity or dystonia combined with static structural factors such as curvature flexibility can result in deformity and often lead to traumatic spinal cord injury. In addition, postoperative complication rate is higher due to abnormal involuntary movement and muscle tone. Therefore, it is important to control abnormal involuntary movement perioperatively along with strong instrumentation for correction of deformity. Various methods such as botulinum toxin injection, physical therapy, muscle division technique, or intrathecal baclofen pump implant may help control abnormal involuntary movements and improve spinal stability. Surgical management for cervical deformities associated with NMDs requires a multidisciplinary effort and a customized strategy.

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.

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.

Iatrogenic biological fracture of the cervical spine during gradual halo traction for kyphotic deformity correction: case report

Background

Severe kyphotic deformities carry high risk for neurological injuries as osteotomies are often required for correction. Surgeons often utilize a staged approach for dealing with these conditions starting with a period of halo traction to stretch tight soft tissues and partially correct the deformity, followed by surgery. Halo traction is a relatively safe procedure and complications are uncommon. We report a unique case of iatrogenic fracture of the cervical spine during gradual halo traction for deformity correction of a severe cervical kyphosis.

Case presentation

An 80-year-old female with previous cervical spine tuberculosis infection and C5-C6 anterior spinal fusion developed severe cervical kyphosis of 64° from C2-C6 and neck pain requiring deformity correction surgery. Gradual increase in traction weight was applied, aiming for a maximum traction weight of 45 pounds or half body weight. During the 1st stage halo-gravity traction, sudden neck pain and a loud cracking sound was witnessed during increase of the traction weight to 14 pounds. Imaging revealed a fracture through the C4 and reduction in kyphosis deformity to 11° from C2-C6. There was no neurological deficit. No further traction was applied and the patient underwent an in-situ occipital to T3 fusion without osteotomies. At 3-year follow-up, the patient was symptom-free and radiographs showed solid fusion and maintenance of alignment.

Conclusions

Iatrogenic fracture may occur with halo traction. Elderly patients with osteoporotic and diseased bone should be closely monitored during the treatment. A fracture without complications was a fortunate complication as the patient was able to avoid any high-risk osteotomies for deformity correction.

Level of evidence

IV

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.

Cervical Spine Deformity Correction Techniques

Cervical kyphotic deformity can be a debilitating condition with symptoms ranging from mechanical neck pain, radiculopathy, and myelopathy to impaired swallowing and horizontal gaze. Surgical correction of cervical kyphosis has the potential to halt progression of neurological and clinical deterioration and even restore function. There are various operative approaches and deformity correction techniques. Choosing the optimal strategy is predicated on a fundamental understanding of spine biomechanics. Preoperative characterization of cervical malalignment, assessment of deformity rigidity, and defining postoperative clinical and radiographic objectives are paramount to formulating a surgical plan that balances clinical benefit with morbidity. This review of cervical deformity treatment provides an overview of the biomechanics of cervical kyphosis, radiographic classification, algorithm-based management, surgical techniques, and current surgical outcome studies.

Computer-Assisted Navigation for Real Time Planning of Pedicle Subtraction Osteotomy in Cervico-Thoracic Deformity Correction

BACKGROUND

Pedicle subtraction osteotomy (PSO) at the cervicothoracic junction (CTJ) is a powerful technique to correct severe kyphosis and sagittal malalignment. Reported techniques have demonstrated the safety and efficacy of the PSO, however limited visualization of surrounding tissues increases the potential for complications with this advanced technique.

OBJECTIVE

To describe the application of computed tomographic (CT)-based image guidance to the planning and execution of PSO at the CTJ.

METHODS

Intraoperative registration and verification of anatomic landmarks are performed with the intraoperative O-arm CT across the CTJ. With the navigation probe, the targeted pedicle is identified and the intended trajectories are rehearsed and saved on the navigational computer. As the PSO is performed, the navigation probe is used to check the depth, accuracy, and trajectory through each side. The extent of soft tissue dissection around the lateral aspect of the vertebral body through which the PSO is performed is also verified in real time. This technique was performed in 12 consecutive patients from 2013-2016. An IRB approved, retrospective analysis was performed from a prospective spinal deformity outcomes database. Patient consent is not required for publication as this report does not describe a specific case but rather a surgical technique used in practice.

RESULTS

There were no vascular, esophageal, or soft tissue injuries in 12 consecutive patients. There were no cases of paralysis. Two patients developed hand weakness days after surgery. Intraoperative O-arm CT performed after closure of the osteotomy confirmed the accuracy of the osteotomy planning with no breach of the anterior cortical wall of the osteotomized vertebral body.

CONCLUSION

CT-guided navigation allows for 3-dimensional visualization of the CTJ and minimizes complications associated with inadequate surgical visualization of vascular and deep organ structures.