Should Multilevel Posterior Cervical Fusions Involving C7 Cross the Cervicothoracic Junction? A Systematic Review and Meta-Analysis

Prosthesis optimization and mechanical analysis of artificial lumbar disc replacement

BACKGROUND

Artificial lumbar disc replacement is an effective method for the treatment of lumbosacral degenerative diseases. An appropriate artificial intervertebral disc device is of great significance for the maintenance of spinal stability and activity.

METHODS

Two finite element models of ProDisc-L prosthesis replacement and improved prosthesis replacement were constructed by using the finite element model of complete lumbar L1-L5 segment established by CT image data. The mechanical properties of the surgical models before and after improvement were analyzed and evaluated.

RESULTS

The ProDisc-L group and the improved group showed similar lumbar's ROM and maintained a similar ROM with the normal lumbar spine. There was no significant change in the intervertebral disc's pressure between the adjacent segments of the two prosthesis groups compared with the normal group, but the stress value of the improved prosthesis group was slightly lower than that of the ProDisc-L group. In addition, the improved prosthesis replacement has more reasonable stress distribution.

CONCLUSIONS

Compared with the ProDisc-L prosthesis, the improved prosthesis can reduce the pressure in the intervertebral disc of the adjacent segment, the contact stress of the facet joint and the artificial prosthesis, which provides reference for the subsequent design of the prosthesis structure.

To Cross the Cervicothoracic Junction? Terminating Posterior Cervical Fusion Constructs Proximal to the Cervicothoracic Junction Does Not Impart Increased Risk of Reoperation in Patients With Cervical Spondylotic Myelopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To evaluate the effect of caudal instrumentation level on revision rates following posterior cervical laminectomy and fusion.

METHODS

A retrospective review of a prospectively collected database was performed. Minimum follow-up was one year. Patients were divided into two groups based on the caudal level of their index fusion construct (Group 1-cervical and Group 2- thoracic). Reoperation rates were compared between the two groups, and preoperative demographics and radiographic parameters were compared between patients who required revision and those who did not. Multivariate binomial regression analysis was performed to determine independent risk factors for revision surgery.

RESULTS

One hundred thirty-seven (137/204) patients received fusion constructs that terminated at C7 (Group 1), while 67 (67/204) received fusion constructs that terminated at T1 or T2 (Group 2). The revision rate was 8.33% in the combined cohort, 7.3% in Group 1, and 10.4% in Group 2. There was no significant difference in revision rates between the 2 groups (P = .43). Multivariate regression analysis did not identify any independent risk factors for revision surgery.

CONCLUSION

This study shows no evidence of increased risk of revision in patients with fusion constructs terminating in the cervical spine when compared to patients with constructs crossing the cervicothoracic junction. These findings support terminating the fusion construct proximal to the cervicothoracic junction when indicated.

LEVEL OF EVIDENCE

III.

The influence of over-distraction on biomechanical response of cervical spine post anterior interbody fusion: a comprehensive finite element study

Introduction: Anterior cervical discectomy and fusion (ACDF) has been considered as the gold standard surgical treatment for cervical degenerative pathologies. Some surgeons tend to use larger-sized interbody cages during ACDF to restore the index intervertebral disc height, hence, this study evaluated the effect of larger-sized interbody cages on the cervical spine with ACDF under both static and cyclic loading. Method: Twenty pre-operative personalized poro-hyperelastic finite element (FE) models were developed. ACDF post-operative models were then constructed and four clinical scenarios (i.e., 1) No-distraction; 2) 1 mm distraction; 3) 2 mm distraction; and 4) 3 mm distraction) were predicted for each patient. The biomechanical responses at adjacent spinal levels were studied subject to static and cyclic loading. Non-parametric Friedman statistical comparative tests were performed and the p values less than 0.05 were reflected as significant. Results: The calculated intersegmental range of motion (ROM) and intradiscal pressure (IDP) from 20 pre-operative FE models were within the overall ranges compared to the available data from literature. Under static loading, greater ROM, IDP, facet joint force (FJF) values were detected post ACDF, as compared with pre-op. Over-distraction induced significantly higher IDP and FJF in both upper and lower adjacent levels in extension. Higher annulus fibrosus stress and strain values, and increased disc height and fluid loss at the adjacent levels were observed in ACDF group which significantly increased for over-distraction groups. Discussion: it was concluded that using larger-sized interbody cages (the height of ≥2 mm of the index disc height) can result in remarkable variations in biomechanical responses of adjacent levels, which may indicate as risk factor for adjacent segment disease. The results of this comprehensive FE investigation using personalized modeling technique highlight the importance of selecting the appropriate height of interbody cage in ACDF surgery.

Biomechanical Analysis of Multilevel Posterior Cervical Spinal Fusion Constructs

STUDY DESIGN

Controlled Laboratory Study.

OBJECTIVE

To compare multilevel posterior cervical fusion (PCF) constructs stopping at C7, T1, and T2 under cyclic load to determine the range of motion (ROM) between the lowest instrumented level and lowest instrumented-adjacent level (LIV-1).

SUMMARY OF BACKGROUND DATA

PCF is a mainstay of treatment for various cervical spine conditions. The transition between the flexible cervical spine and rigid thoracic spine can lead to construct failure at the cervicothoracic junction. There is little evidence to determine the most appropriate level at which to stop a multilevel PCF.

METHODS

Fifteen human cadaveric cervicothoracic spines were randomly assigned to 1 of 3 treatment groups: PCF stopping at C7, T1, or T2. Specimens were tested in their native state, following a simulated PCF, and after cyclic loading. Specimens were loaded in flexion-extension), lateral bending, and axial rotation. Three-dimensional kinematics were recorded to evaluate ROM.

RESULTS

The C7 group had greater flexion-extension motion than the T1 and T2 groups following instrumentation (10.17±0.83 degree vs. 2.77±1.66 degree and 1.06±0.55 degree, P <0.001), and after cyclic loading (10.42±2.30 degree vs. 2.47±0.64 degree and 1.99±1.23 degree, P <0.001). There was no significant difference between the T1 and T2 groups. The C7 group had greater lateral bending ROM than both thoracic groups after instrumentation (8.81±3.44 degree vs. 3.51±2.52 degree, P =0.013 and 1.99±1.99 degree, P =0.003) and after cyclic loading. The C7 group had greater axial rotation motion than the thoracic groups (4.46±2.27 degree vs. 1.26±0.69 degree, P =0.010; and 0.73±0.74 degree, P =0.003) following cyclic loading.

CONCLUSION

Motion at the cervicothoracic junction is significantly greater when a multilevel PCF stops at C7 rather than T1 or T2. This is likely attributable to the transition from a flexible cervical spine to a rigid thoracic spine. Although this does not account for in vivo fusion, surgeons should consider extending multilevel PCF constructs to T1 when feasible.

LEVEL OF EVIDENCE

Not applicable.

Is It Necessary to Cross the Cervicothoracic Junction in Posterior Cervical Decompression and Fusion for Multilevel Degenerative Cervical Spine Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Posterior cervical decompression and fusion (PCF) is a common procedure for treating patients with multilevel degenerative cervical spine disease. The selection of lower instrumented vertebra (LIV) relative to the cervicothoracic junction (CTJ) remains controversial. This study aimed to compare the outcomes of PCF construct terminating at the lower cervical spine and crossing the CTJ.

METHODS

A comprehensive literature search was performed for relevant studies in the PubMed, EMBASE, Web of Science, and Cochrane Library database. Complications, rate of reoperation, surgical data, patient-reported outcomes (PROs), and radiographic outcomes were compared between PCF construct terminating at or above C7 (cervical group) and at or below T1 (thoracic group) in patients with multilevel degenerative cervical spine disease. A subgroup analysis based on surgical techniques and indications was performed.

RESULTS

Fifteen retrospective cohort studies comprising 2071 patients (1163 in the cervical group and 908 in the thoracic group) were included. The cervical group was associated with a lower incidence of wound-related complications (RR, 0.58; 95% CI 0.36 to 0.92, p = 0.022; 831 patients in cervical group vs. 692 patients in thoracic group), a lower reoperation rate for wound-related complications (RR, 0.55; 95% CI 0.32 to 0.96, p = 0.034; 768 vs. 624 patients), and less neck pain at the final follow-up (WMD, -0.58; 95% CI -0.93 to -0.23, p = 0.001; 327 vs. 268 patients). However the cervical group also developed a higher incidence of overall adjacent segment disease (ASD, including distal ASD and proximal ASD) (RR, 1.87; 95% CI 1.27 to 2.76, p = 0.001; 1079 vs. 860 patients), distal ASD (RR, 2.18; 95% CI 1.36 to 3.51, p = 0.001; 642 vs. 555 patients), overall hardware failure (including hardware failure of LIV and hardware failure occurring at other instrumented vertebra) (RR, 1.48; 95% CI 1.02 to 2.15, p = 0.040; 614 vs. 451 patients), and hardware failure of LIV (RR, 1.89; 95% CI 1.21 to 2.95, p = 0.005; 380 vs. 339 patients). The operating time was reasonably shorter (WMD, -43.47; 95% CI -59.42 to -27.52, p < 0.001; 611 vs. 570 patients) and the estimated blood loss was lower (WMD, -143.77; 95% CI -185.90 to -101.63, p < 0.001; 721 vs. 740 patients) when the PCF construct did not cross the CTJ.

CONCLUSIONS

PCF construct crossing the CTJ was associated with a lower incidence of ASD and hardware failure but a higher incidence of wound-related complications and a small increase in qualitative neck pain, without difference in neck disability on the NDI. Based on the subgroup analysis for surgical techniques and indications, prophylactic crossing of the CTJ should be considered for patients with concurrent instability, ossification, deformity, or a combination of anterior approach surgeries as well. However, long-term follow-up outcomes and patient selection-related factors such as bone quality, frailty, and nutrition status should be addressed in further studies.

Does Ending a Posterior Construct Proximally at C2 Versus C3 Impact Patient Reported Outcomes in Degenerative Cervical Myelopathy Patients up to 24 months After the Surgery?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The primary objective was to evaluate the impact of the upper instrumented level (UIV) being at C2 vs C3 in posterior cervical construct on patient reported outcomes (PROs) up to 24 months after surgery for cervical degenerative myelopathy (DCM). Secondary objectives were to compare operative time, intra-operative blood loss (IOBL), length of stay (LOS), adverse events (AEs) and re-operation.

METHODOLOGY

Patients who underwent a posterior cervical instrumented fusion (3 and + levels) with a C2 or C3 UIV, with 24 months follow-up were analyzed. PROs (NDI, EQ5D, SF-12 PCS/MCS, NRS arm/neck pain) were compared using ANCOVA. Operative duration, IOBL, AEs, and re-operation were compared. Subgroup analysis was performed on patient presenting with pre-operative malalignment (cervical sagittal vertical axis ≥40 mm and/or T1slope- cervical lordosis >15°).

RESULTS

173 patients were included, of which 41 (24%) had a C2 UIV and 132 (76%) a C3 UIV. There was no statistically significant difference between the groups for the changes in PROs up to 24 months. Subgroup analysis of patients with pre-operative malalignment showed a trend towards greater improvement in the NDI at 12 months with a C2 UIV (P = .054). Operative time, IOBL and peri-operative AEs were more in C2 group (P < .05). There was no significant difference in LOS and re-operation (P > .05).

CONCLUSION

In this observational study, up to 24 months after surgery for posterior cervical fusion in DCM greater than 3 levels, PROs appear to evolve similarly.

Bridging the Cervicothoracic Junction During Multi-Level Posterior Cervical Decompression and Fusion: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and Meta-analysis.

OBJECTIVE

This systematic review seeks to compare fusion, reoperation and complication rates, estimated blood loss (EBL), and surgical time between multi-level instrumented fusions with LIVs (lowest instrumented vertebra) in the cervical spine and those that extend into the thoracic spine.

SUMMARY OF BACKGROUND DATA

Several studies address the question of whether to extend a long-segment, posterior cervical fusions, performed for degenerative disease, into the upper thoracic spine. Recommendations for appropriate LIV continue to vary.

METHODS

A comprehensive computerized literature search through multiple electronic databases without date limits up until April 3rd, 2020 using combinations of key search terms and sets of inclusion/exclusion criteria was performed.

RESULTS

Our comprehensive literature search yielded 3852 studies. Of these, 8 articles consisting of 1162 patients were included in the meta-analysis. In 61.2% of the patients, the fusion did not cross the cervicothoracic junction (CTJ) (cervical LIV, CLV). In the remaining 38.8%, the fusion extended into the upper thoracic spine (thoracic LIV, TLV). Overall, mean patient age was 62.5 years (range: 58.8-66.1 years). Our direct analysis showed that odds of fusion were not statistically different between the CLV and TLV groups (OR: .648, 95% CI: .336-1.252, P = .197). Similarly, odds of reoperation (OR: 0.726, 95% CI: 0.493-1.068, P = .104) and complication rates were similar between the 2 groups (OR: 1.214, 95% CI: 0.0.750-1.965, P = .430). Standardized mean difference (SMD) for the blood loss (SMD: .728, 95% CI: 0.554-.901, P = .000) and operative (SMD: 0.653, 95% CI: .479-.826, P = .000) differed significantly between the 2 groups. The indirect analysis showed similar fusion (Effect Size (ES)_TLV: .892, 95% CI: .840-.928 vs ES_CLV:0.894, 95% CI:0.849-.926); reoperation rate (ES_TLV:0.112, 95% CI: 0.075-.164 vs ES_CLV: .125, 95% CI: .071-.211) and complication rates (ES_TLV: .108, 95% CI: .074-.154 vs ES_CLV:0.081, 95% CI: .040-.156).

CONCLUSIONS

Our meta-analysis showed that fusion, complication, and reoperation rates did not differ significantly between patients in whom multi-level posterior fusions ended in the cervical spine vs those of which was extended into the thoracic spine. The mean blood loss, operative time and length of stay were significantly lower in patients with CLV at C6 or C7, compared to their counterparts. These data suggest that, absent focal, C7-T1 pathology, extension of long, posterior cervical fusions into the thoracic spine may not be necessary.

Should cervicothoracic junctions be avoided in long cervical posterior fusion surgery? Analysis of clinical and radiologic outcomes over two years

PURPOSE

This study aimed to confirm the usefulness of surgery that avoids the cervicothoracic junction (CTJ) by comparing the clinical and radiographic outcomes after posterior cervical fusion at C5/6 with those at C7/T1.

METHODS

Patients who underwent laminectomy and posterior cervical instrument fusion for cervical spondylotic myelopathy (CSM) from 2012 to 2019 were retrospectively reviewed and divided according to whether the end level was at C5/6 (group 1) or C7/T1 (group 2). Demographic variables and incidence of distal junctional kyphosis (DJK) were compared between the groups. Clinical outcomes (visual analog scale [VAS] score for arm and neck pain and the Neck Disability Index value) and radiologic outcomes (T1 slope, cervical lordosis, segmental lordosis, C2-7 sagittal vertical axis, T1 slope-cervical lordosis mismatch) were compared over time.

RESULTS

Sixty-seven patients were included. There were 32 patients in group 1 and 35 in group 2. The VAS score for neck pain was significantly lower in group 1 than in group 2 at 2 years after surgery (p = 0.03). The C2-7 sagittal vertical axis was significantly larger in group 2 than in group 1 at 1 year and 2 years postoperatively (p = 0.04). The incidence of DJK was higher in group 2 than in group 1 (28.57% vs 9.37%, p = 0.04).

CONCLUSION

This study found that when CTJs are included in the posterior cervical long fusion surgery, although it would be better than preoperation, postoperative kyphosis and consequent neck pain may progress. The results of this study advocate the concept of avoiding CTJ fusion if possible.

Does extending a posterior cervical fusion construct into the upper thoracic spine impact patient-reported outcomes as long as 2 years after surgery in patients with degenerative cervical myelopathy?

OBJECTIVE

In multilevel posterior cervical instrumented fusion, extension of fusion across the cervicothoracic junction (CTJ) at T1 or T2 has been associated with decreased rates of reoperation and pseudarthrosis but with longer surgical time and increased blood loss. The impact on patient-reported outcomes (PROs) remains unclear. The primary objective was to determine whether extension of fusion through the CTJ influenced PROs at 3, 12, and 24 months after surgery. The secondary objective was to compare the number of patients who reached the minimal clinically important differences (MCIDs) for the PROs, modified Japanese Orthopaedic Association (mJOA) score, operative time, intraoperative blood loss, length of stay, discharge disposition, adverse events (AEs), reoperation within 24 months of surgery, and patient satisfaction.

METHODS

This was a retrospective observational cohort study of prospectively collected multicenter data of patients with degenerative cervical myelopathy. Patients who underwent posterior instrumented fusion of 4 levels or greater (between C2 and T2) between January 2015 and October 2020 and received 24 months of follow-up were included. PROs (scores on the Neck Disability Index [NDI], EQ-5D, physical component summary and mental component summary of SF-12, and numeric rating scale for arm and neck pain) and mJOA scores were compared using ANCOVA and adjusted for baseline differences. Patient demographic characteristics, comorbidities, and surgical details were abstracted. The proportions of patients who reached the MCIDs for these outcomes were compared with the chi-square test. Operative duration, intraoperative blood loss, AEs, reoperation, discharge disposition, length of stay, and satisfaction was compared by using the chi-square test for categorical variables and the independent-samples t-test for continuous variables.

RESULTS

A total of 198 patients were included in this study (101 patients with fusion not crossing the CTJ and 97 with fusion crossing the CTJ). Patients with a construct extending through the CTJ were more likely to be female and have worse baseline NDI scores (p > 0.05). When adjusted for baseline differences, there were no statistically significant differences between the two groups in terms of the PROs and mJOA scores at 3, 12, and 24 months. Surgical duration was longer (p < 0.001) and intraoperative blood loss was greater in the group with fusion extending to the upper thoracic spine (p = 0.013). There were no significant differences between groups in terms of AEs (p > 0.05). Fusion with a construct crossing the CTJ was associated with reoperation (p = 0.04). Satisfaction with surgery was not significantly different between groups. The proportions of patients who reached the MCIDs for the PROs were not statistically different at any time point.

CONCLUSIONS

There were no statistically significant differences in PROs between patients with a posterior construct extending to the upper thoracic spine and those without such extension for as long as 24 months after surgery. The AE profiles were not significantly different, but longer surgical time and increased blood loss were associated with constructs extending across the CTJ.

Instrumentation Across the Cervicothoracic Junction Does Not Improve Patient-reported Outcomes in Multilevel Posterior Cervical Decompression and Fusion

STUDY DESIGN

This was a retrospective cohort.

OBJECTIVE

The objective of this study was to determine if instrumentation across the cervicothoracic junction (CTJ) in elective multilevel posterior cervical decompression and fusion (PCF) is associated with improved patient-reported outcome measures (PROMs).

SUMMARY OF BACKGROUND DATA

Fusion across the CTJ may result in lower revision rates at the expense of prolonged operative duration. However, it is unclear whether constructs crossing the CTJ affect PROMs.

MATERIALS AND METHODS

Standard Query Language (SQL) identified patients with PROMs who underwent elective multilevel PCF (≥3 levels) at our institution. Patients were grouped based on anatomic construct: crossing the CTJ (crossed) versus not crossing the CTJ (noncrossed). Subgroup analysis compared constructs stopping at C7 or T1. Independent t tests and χ 2 tests were utilized for continuous and categorical data, respectively. Regression analysis controlled for baseline demographics. The α was set at 0.05.

RESULTS

Of the 160 patients included, the crossed group (92, 57.5%) had significantly more levels fused (5.27 vs. 3.71, P <0.001), longer operative duration (196 vs. 161 min, P =0.003), greater estimated blood loss (242 vs. 160 mL, P =0.021), and a decreased revision rate (1.09% vs. 10.3%, P =0.011). Neither crossing the CTJ (vs. noncrossed) nor constructs spanning C3-T1 (vs. C3-C7) were independent predictors of ∆PROMs (change in preoperative minus postoperative patient-reported outcomes) on regression analysis. However, C3-C7 constructs had a greater revision rate than C3-T1 constructs (15.6% vs. 1.96%, P =0.030).

CONCLUSION

Crossing the CTJ in patients undergoing elective multilevel PCF was not an independent predictor of improvement in PROMs at 1 year, but they experienced lower revision rates.

LEVEL OF EVIDENCE

Level III.

Comparative biomechanical analyses of lower cervical spine post anterior fusion versus intervertebral disc arthroplasty: A geometrically patient-specific poroelastic finite element investigation

Background/Objective

The optimal surgical technique for the treatment of cervical degenerative disc disease (CDDD) towards decreasing the risk of adjacent segment disease (ASD) remains elusive. This study aimed to comparatively investigate the biomechanics of the lower cervical spine following fusion (ACDF) and artificial disc arthroplasty (Bryan® and Prestige LP®) using a validated geometrically patient-specific poroelastic finite element modeling (FEM) approach.

Methods

Ten subject-specific pre-operative models were developed and validated based on a FEM approach. Poroelastic models were then constructed using post-operation images for three different treatment scenarios: ACDF; Prestige LP® and Bryan® artificial discs at the C5-C6 level. The biomechanical responses at both surgical and adjacent spinal levels were studied subject to static and cyclic loading.

Results

Postoperatively, greater range of motion (ROM), higher annulus fibrosus stress and strain values, and increased disc height and fluid loss at the adjacent levels were detected post ACDF, as compared with pre-op as well as artificial disc arthroplasty. The facet joint forces were larger for the Prestige LP® disc, particularly during extension. The lowest values in disc height and fluid exchange were observed in the Bryan® artificial disc arthroplasty models.

Conclusion

Biomechanical analyses revealed that ACDF poses the highest potential risk for adjacent disc degeneration. The artificial discs investigated here (Prestige LP® and Bryan®) not only preserved motion at the instrumented level, but also sustained the pre-op ROM and decreased the intradiscal pressure (IDP) and facet joint forces (FJFs) at adjacent levels, particularly during flexion/extension. The Bryan® artificial disc demonstrated the most efficacy in maintaining the natural poroelastic characteristics of adjacent discs.

The translational potential of this article

This study provided a technique for clinicians to use quantitative data towards subject-specific evaluation to comparatively evaluate the impact of ACDF and disc arthroplasty using two types of artificial discs on the biomechanics of the cervical spine. It confirms differences in the poroelastic characteristics of adjacent discs for different fixation techniques, and reveals the advantage of artificial discs with a flexible core for decreasing the risk of ASD.

Should we bridge the cervicothoracic junction in long cervical fusions? A meta-analysis and systematic review of the literature

OBJECTIVE

Long posterior cervical decompression and fusion (PCF) is commonly performed to surgically treat patients with multilevel cervical pathology. In cases in which constructs may necessitate crossing the cervicothoracic junction (CTJ), recommendations for appropriate caudal fusion level vary in the literature. The aim of this study was to report the clinical and radiological outcomes of multilevel PCFs ending at C7 versus those crossing the CTJ.

METHODS

A systematic search of PubMed, CINAHL Plus, and Scopus was conducted to identify articles that evaluated clinical and radiological outcomes of long PCFs that ended at C7 (cervical group) or crossed the CTJ (thoracic group). Based on heterogeneity, random-effects models of a meta-analysis were used to estimate the pooled estimates and the 95% confidence intervals.

RESULTS

PCF outcome data of 1120 patients from 10 published studies were included. Compared with the cervical group, the thoracic group experienced greater mean blood loss (453.0 ml [95% CI 333.6-572.5 ml] vs 303.5 ml [95% CI 203.4-403.6 ml]), longer operative times (235.5 minutes [95% CI 187.7-283.3 minutes] vs 198.5 minutes [95% CI 157.9-239.0 minutes]), and a longer length of stay (6.7 days [95% CI 3.3-10.2 days] vs 6.2 days [95% CI 3.8-8.7 days]); however, these differences were not statistically significant. None of the included studies specifically investigated factors that led to the decision of whether to cross the CTJ. The cervical group had a mean fusion rate of 86% (95% CI 71%-94%) compared with the thoracic group with a rate of 90% (95% CI 81%-95%). Of patients in the cervical group, 17% (95% CI 10%-28%) required revision surgery compared with 7% (95% CI 4%-13%) of those in the thoracic group, but this difference was not statistically significant. The proportion of patients who experienced complications in the cervical group was found to be 28% (95% CI 12%-52%) versus 14% (95% CI 7%-26%) in the thoracic group; however, this difference was not statistically significant. There was no significant difference (no overlap of 95% CIs) in the incidence of adjacent-segment disease, pseudarthrosis, or wound-related complications between groups.

CONCLUSIONS

This meta-analysis suggests similar clinical and radiographic outcomes in multilevel PCF, regardless of inclusion of the CTJ. The lowest instrumented level did not significantly affect revision rates or complications. The ideal stopping point must be tailored to each patient on an individualized basis.

Cervical Alignment and Proximal and Distal Junctional Failure in Posterior Cervical Fusion: A Multicenter Comparison of 2 Surgical Approaches

STUDY DESIGN

This was a multicenter retrospective cohort study.

OBJECTIVE

The purpose of this study was to compare the surgical and radiographic outcomes of patients undergoing posterior cervical fusion (PCF) with constructs extending from C2 to T2 to patients with constructs extending from C3 to T1.

SUMMARY OF BACKGROUND DATA

Limited evidence exists regarding the appropriate level of proximal and distal extension of PCF constructs.

METHODS

A multicenter retrospective cohort study of patients who underwent PCF between 2012 and 2020 was performed. Surgical and radiographic outcomes were compared between those who had C3-T1 or C2-T2 constructs.

RESULTS

A total of 155 patients were included in the study (C2-T2: 106 patients, C3-T1: 49 patients). There were no significant differences in demographics or preoperative symptoms between cohorts. Fusion rates were significantly higher in the C2-T2 (93%) than the C3-T1 (80%, P=0.040) cohort. When comparing the C2-T2 to the C3-T1 cohort, the C3-T1 cohort had a significantly greater rate of proximal junctional failure (2% vs. 10%, P=0.006), distal junctional failure (1% vs. 20%, P<0.001) and distal screw loosening (4% vs. 15%, P=0.02). Although ∆C2-C7 sagittal vertical axis increased significantly in both cohorts (C2-T2: 6.2 mm, P=0.04; C3-T1: 8.4 mm, P<0.001), correction did not significantly differ between groups (P=0.32). The C3-T1 cohort had a significantly greater increase in ∆C2 slope (8.0 vs. 3.1 degrees, P=0.03) and ∆C0-C2 Cobb angle (6.4 vs. 1.2 degrees, P=0.04).

CONCLUSION

In patients undergoing PCF, a C2-T2 construct demonstrated lower rates of pseudarthrosis, distal junctional failure, proximal junctional failure, and compensatory upper cervical hyperextension compared with a C3-T1 construct.

To cross or not to cross the cervicothoracic junction in multilevel posterior cervical fusion: a systematic review and meta-analysis

BACKGROUND

Inclusion of the cervicothoracic junction (CTJ) during decision-making regarding the surgical level of multilevel posterior cervical fusion (PCF) surgery remains the subject of debate, largely due to a lack of studies on the topic. Thus, we considered that meta-analysis based on recent high-quality clinical studies might enable better-informed decision-making regarding the selection of the distal level of multilevel PCF, particularly concerning the advisability of crossing the CTJ.

PURPOSE

To compare the outcomes of patients who underwent multilevel PCF with or without crossing the CTJ (the thoracic and cervical groups, respectively) by the distal construct.

STUDY DESIGN

A systematic review and meta-analysis.

METHODS

We searched the Cochrane, Embase, and Medline databases for articles that compared the intra- and post-operative outcomes of patients who underwent multilevel PCF surgery with or without extension of surgery to include the CTJ, using January 7, 2021, as the publication cutoff date. Group differences in primary and secondary outcome measures were analyzed for significance (p<.05). All reported means were pooled.

RESULTS

A total of 1,904 publications were assessed, and eight studies met the study criteria. The cervical group had a significantly greater fusion rate than the thoracic group (p=.03), but higher adjacent segment disease (ASD) and reoperation rates (ASD: OR=3.15, p=.007; reoperation: OR=1.93, p=.008). As regards surgical outcomes, mean blood loss was less and operation time was shorter in the cervical group (p=.008 and .009, respectively). However, mean hospital stays were not significantly different (p=.12), and neither were the rates of complications, such as metal failure and hematoma.

CONCLUSIONS

In the current study, fusion rate, blood loss, and operation time were better in the cervical group than in the thoracic group, but ASD incidence and ASD-related complication rates at the CTJ were greater in the cervical group. For patients with higher risk factors for adjacent-segment degeneration, crossing the CTJ may be warranted.

Is it Better to Stop at C2 or C3/4 in Elective Posterior Cervical Decompression and Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

(a) Compare operative variables, complications, and patient-reported outcomes (PROs) in patients with an upper instrumented vertebrae (UIV) of C2 versus C3/4, and (b) assess outcomes based on C2 screw type.

SUMMARY OF BACKGROUND DATA

When performing elective posterior cervical laminectomy and fusion (PCLF), spine surgeons must choose the upper instrumented vertebrae (UIV) at the subaxial cervical spine (C3/4) versus C2. Differences in long-term complications and PROs remain unknown.

METHODS

A single-institution, retrospective cohort study from a prospective registry was conducted. All patients undergoing elective, degenerative PCLF from December 2010 to June 2018 were included. Patients were divided into a UIV of C2 versus C3/4. Groups were 2:1 propensity matched for fusion extending to the thoracic spine. Demographics, operative, perioperative, complications, and 1-year PRO data were collected.

RESULTS

One hundred seventeen patients underwent elective PCLF and were successfully propensity matched (39 C2 vs. 78 C3/4). Groups were similar in fusion extending to the thoracic spine (P = 0.588). Expectedly, the C2 group had more levels fused (5.63 ± 1.89) compared with the C3/4 group (4.50 ± 0.91) (P = 0.001). The C2 group had significantly longer operative time (P < 0.001), yet no differences were seen in estimated blood loss (EBL) (P = 0.494) or length of stay (LOS) (P = 0.424). Both groups significantly improved all PROs at 1-year (EQ-5D; NRS-NP/AP; NDI). Both groups had the same percentage of surgical adverse events at 6.8% (P = 1.00). Between C2 screw type, no differences were seen in operative time, EBL, LOS, complications, or PROs.

CONCLUSION

In patients undergoing elective PCLF, those instrumented to C2 had only longer operative times compared with those stopping at C3/4. No differences were seen in EBL, LOS, 1-year PROs, and complications. Type of C2 screw had no impact on outcomes. Besides increased operative time, instrumenting to C2 had no detectable difference on surgical outcomes or adverse event rates.Level of Evidence: 3.

Crossing the Cervicothoracic Junction in Multilevel Cervical Arthrodesis: A Systematic Review & Meta-Analysis

INTRODUCTION

In multisegment cervical arthrodeses, a common clinical dilemma for the surgeon is whether to extend the fusion past the cervicothoracic junction (CTJ).

OBJECTIVE

This meta-analysis compares clinical outcomes and radiological parameters when crossing and not crossing the CTJ.

METHODS

Our outcomes of interest included overall reoperation, successful fusion, adjacent segment disease (ASD) leading to revision surgery, estimated blood loss (EBL), length of stay (LOS). We also studied the postoperative change in radiological parameters - cervical sagittal vertical axis (cSVA), cervical lordosis (CL), and T1 slope (T1S) - and change in Neck Disability Index (NDI) and neck pain in Visual Analog Scale (VAS).

RESULTS

Thirteen studies with 1,720 patients were included. There were 974 (56.6%) patients in the non-crossing group and 746 (43.4%) patients in the crossing group. Non-crossing was associated with a higher risk of overall reoperation (RR=1.56; 95% CI:0.98-2.47) and ASD requiring revision surgery (RR=2.82; 95% CI:1.33-5.98; number-needed-to-harm = 22). The non-crossing group had lower EBL by 175 mL and shorter LOS by one day; the latter finding was only trending towards statistical significance. Successful fusion, as well as changes in cSVA, CL, NDI, and VAS were not different between the two groups at a statistically significant level.

CONCLUSIONS

In multilevel cervical arthrodesis, not crossing the CTJ is associated with a higher risk of overall reoperation and ASD requiring reoperation than crossing the CTJ, along with lower EBL and LOS. Differences in successful fusion, patient-reported outcomes, and sagittal radiological parameters were not significant.

No Difference in Reoperation Rates for Adjacent Segment Disease (Operative Adjacent Segment Disease) in Posterior Cervical Fusions Stopping at C7 Versus T1/T2: A Cohort of 875 Patients-Part 1

STUDY DESIGN

A retrospective cohort study with chart review.

OBJECTIVE

To determine whether there is a difference in reoperation rates for adjacent segment disease ([ASD] operative ASD) in posterior cervical fusions (PCFs) that stop at -C7 versus -T1/T2.

SUMMARY OF BACKGROUND DATA

There are surgical treatment challenges to the anatomical complexities of the cervicothoracic junction. Current posterior cervical spine surgery is based on the belief that ASD occurs if fusions are stopped at C7 although there is varying evidence to support this assumption.

METHODS

Patients were followed until validated reoperations for ASD, membership termination, death, or March 31, 2020. Descriptive statistics and 5-year crude incidence rates and 95% confidence intervals for operative ASD for PCF ending at -C7 or -T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox-Proportional Hazards models were used to evaluate operative ASD rates with adjustment for covariates or risk change estimates more than 10%.

RESULTS

We identified 875 patients with PCFs (beginning at C3 or C4 or C5 or C6) stopping at either -C7 (n = 470) or -T1/T2 (n = 405) with average follow-up time of 4.6 (±3.3) years and average time to operative ASD of 2.7 (±2.8) years. Crude overall incidence rates for stopping at -C7 (2.12% [1.02%-3.86%]) and -T1/T2 (2.48% [1.25%-4.40%]) were comparable with no statistical difference in risk (adjusted hazard ratio = 1.47, 95% confidence interval = 0.61-3.53, P = 0.39). In addition, we observed no differences in the probability of operative ASD in competing risk time-dependent models (Grey test P  = 0.448).

CONCLUSION

A large cohort of 875 patients with PCFs stopping at -C7 or -T1/T2 with an average follow-up of more than 4 years found no statistical difference in reoperation rates for ASD (operative ASD).Level of Evidence: 3.

No difference in reoperation rates for nonunions (operative nonunions) in posterior cervical fusions stopping at C7 versus T1/2: a cohort of 875 patients

OBJECTIVE

The challenges of posterior cervical fusions (PCFs) at the cervicothoracic junction (CTJ) are widely known, including the development of adjacent-segment disease by stopping fusions at C7. One solution has been to cross the CTJ (T1/T2) rather than stopping at C7. This approach may have undue consequences, including increased reoperations for symptomatic nonunion (operative nonunion). The authors sought to investigate if there is a difference in operative nonunion in PCFs that stop at C7 versus T1/T2.

METHODS

A retrospective analysis identified patients from the authors' spine registry (Kaiser Permanente) who underwent PCFs with caudal fusion levels at C7 and T1/T2. Demographics, diagnoses, operative times, lengths of stay, and reoperations were extracted from the registry. Operative nonunion was adjudicated via chart review. Patients were followed until validated operative nonunion, membership termination, death, or end of study (March 31, 2020). Descriptive statistics and 2-year crude incidence rates and 95% confidence intervals for operative nonunion for PCFs stopping at C7 or T1/T2 were reported. Time-dependent crude and adjusted multivariable Cox proportional hazards models were used to evaluate operative nonunion rates.

RESULTS

The authors identified 875 patients with PCFs (beginning at C3, C4, C5, or C6) stopping at either C7 (n = 470) or T1/T2 (n = 405) with a mean follow-up time of 4.6 ± 3.3 years and a mean time to operative nonunion of 0.9 ± 0.6 years. There were 17 operative nonunions, and, after adjustment for age at surgery and smoking status, the cumulative incidence rates were similar between constructs stopping at C7 and those that extended to T1/T2 (C7: 1.91% [95% CI 0.88%-3.60%]; T1/T2: 1.98% [95% CI 0.86%-3.85%]). In the crude model and model adjusted for age at surgery and smoking status, no difference in risk for constructs extended to T1/T2 compared to those stopping at C7 was found (adjusted HR 1.09 [95% CI 0.42-2.84], p = 0.86).

CONCLUSIONS

In one of the largest cohort of patients with PCFs stopping at C7 or T1/T2 with an average follow-up of > 4 years, the authors found no statistically significant difference in reoperation rates for symptomatic nonunion (operative nonunion). This finding shows that there is no added risk of operative nonunion by extending PCFs to T1/T2 or stopping at C7.

Crossing the cervicothoracic junction in complex pediatric deformity using anterior cervical discectomy and fusion: a case series

PURPOSE

Proximal instrumentation failure is a challenge in posterior spinal fusions (PSFs) crossing the cervicothoracic junction. High rates of proximal junctional kyphosis (PJK) and loss of fixation have been reported. In this single-center retrospective cohort study, we evaluate the utility of anterior cervical discectomy and fusion (ACDF) in addition to traditional PSF crossing the cervicothoracic junction in order to mitigate implant-related complications.

METHODS

All patients who underwent PSF across the cervicothoracic junction with ACDF with 2 years of follow-up data were reviewed. We analyzed clinical, surgical, and radiographic measures such as operative details, presence of PJK, complications, instrumentation migration, curve angles, and vertebral translation. Measurements were compared statistically using paired samples t-tests.

RESULTS

Ten patients (6 girls, 4 boys) met inclusion criteria with a mean age at surgery of 12.8 ± 3.3 years and follow-up of 3.38 ± 0.9 years. All patients underwent ACDF (range 1-3 levels), and 8 (80%) underwent traction. The average number of levels fused posteriorly was 16.7 ± 4.7 and anteriorly was 2.4 ± 0.7. The major coronal curve averaged 48.8 ± 34.7° preoperatively and 23.3±13.3° postoperatively (p = 0.028). The average major sagittal curve was 83.5 ± 24.2° preoperatively, resolving to 53.9 ± 25.5° (p=0.001). One patient suffered rod breakage at T7, and another developed symptomatic PJK 19 months postoperatively.

CONCLUSION

Our data suggest that ACDF procedures added to PSFs crossing the cervicothoracic junction offer promise for reducing risk for instrumentation-related complications. ACDF also significantly helps improve and maintain both coronal and sagittal correction over 2 years.

LEVEL OF EVIDENCE

4.

Long-segment posterior cervical decompression and fusion: does caudal level affect revision rate?

OBJECTIVE

Posterior cervical decompression and fusion (PCDF) is a commonly performed procedure to address cervical myelopathy. A significant number of these patients require revision surgery for adjacent-segment disease (ASD) or pseudarthrosis. Currently, there is no consensus among spine surgeons on the inclusion of proximal thoracic spine instrumentation. This study investigates the benefits of thoracic extension in long-segment cervical fusions and the potential drawbacks. The authors compare outcomes in long-segment subaxial cervical fusion for degenerative cervical myelopathy with caudal vertebral levels of C6, C7, and T1.

METHODS

A retrospective analysis identified 369 patients who underwent PCDF. Patients were grouped by caudal fusion level. Reoperation rates for ASD and pseudarthrosis, infection, and blood loss were examined. Data were analyzed with chi-square, 1-way ANOVA, and logistic regression.

RESULTS

The total reoperation rate for symptomatic pseudarthrosis or ASD was 4.8%. Reoperation rates, although not significant, were lower in the C3-6 group (2.6%, vs 8.3% for C3-7 and 3.8% for C3-T1; p = 0.129). Similarly, rates of infection were lower in the shorter-segment fusion without achieving statistical significance (2.6% for C3-6, vs 5.6% for C3-7 and 5.5% for C3-T1; p = 0.573). The mean blood loss was documented as 104, 125, and 224 mL for groups 1, 2, and 3, respectively (p < 0.001).

CONCLUSIONS

Given the lack of statistical difference in reoperation rates for long-segment cervical fusions ending at C6, C7, or T1, shorter fusions in high-risk surgical candidates or elderly patients may be performed without higher rates of reoperation.

C2 quad-screws facilitate 4-rod fixation across the cervico-thoracic junction

Background:

Cervical spine deformity is a potentially devitalizing problem. Contemporary techniques for repair and reconstruction include fusion using rods of tapered diameter alone, or quadruple-rod constructs in which primary rods are joined to floating accessory rods by connectors. Here, we present how we utilized a quadruple-rod construct to perform five C2 to thoracic spine fusions.

Methods:

Our hospital electronic medical record revealed five patients who underwent the four rod C2-thoracic spine fixation. Patients ranged in age from 14-years-old to 78-years-old. The mean operative time was 715.8 min (range 549–987 min), and average estimated blood loss was 878 cc (range 40–1800 cc).

Results:

None of the five patients sustained any intraoperative complications, and none demonstrated progressive kyphotic deformity over the average follow-up interval of 8 months.

Conclusion:

We successfully treated five patients with degenerative or oncologic cervical pathology requiring fixation across the cervicothoracic junction utilizing a 4-rod C2-cervicothoracic fusion technique.

Long-Term Results after Multilevel Fusion of the Cervical Spine and the Cervicothoracic Junction: To Bridge or Not To Bridge?

OBJECTIVE

For patients with multilevel degenerative cervical myelopathy, laminectomy and fusion are widely accepted techniques for ameliorating the disorder. However, the idea of whether one should bridge the cervicothoracic junction to prevent instrument failure or adjacent segment disease has been a subject of controversial discussion. In the present study, we compared the incidence of these complications and the revision rates in multilevel fusions extending to C7 or T1-T3.

METHODS

In the present single-center, retrospective cohort study, patients with multilevel degenerative cervical myelopathy treated with laminectomy and fusion to C7 or T1-T3 from 2004 to 2016 were included for evaluation. The primary outcome measure was radiologically proven complications at the most caudal level or the adjacent spinal fusion level.

RESULTS

Laminectomy and multilevel fusion were performed in 84 patients. After applying the exclusion criteria, 20 patients with fusion to C7 (treated from 2004 to 2012; follow-up, 124.6 ± 10.6 months) and 38 patients with fusion to T1-T3 (treated from 2008 to 2016; follow-up, 58.2 ± 15.7 months) were evaluated. The incidence of complications at the most caudal or adjacent level of fusion was twice as high (P = 0.087; NS) in the C7 group (11 of 20; 55.0%) compared with the T1-T3 group (11 of 38; 28.9%). In the C7 group, 9 of the 20 patients (45.0%) had required revision surgery compared with 2 of 38 patients (5.3%) in the T1-T3 group (P = 0.001).

CONCLUSIONS

We found that fewer revisions were necessary if the fusion had extended to the thoracic spine. Thus, we recommend bridging the cervicothoracic junction when fusion starts at C0-C3.

Is it safe to stop at C7 during multilevel posterior cervical decompression and fusion? - multicenter analysis

BACKGROUND CONTEXT

Despite a number of studies addressing the anatomical and biomechanical challenges of long segment, posterior cervical fusion surgery, recommendations for appropriate caudal "end level" vary widely.

PURPOSE

Compare revision rates, patient reported outcomes and radiographic outcomes in patients in whom 3+ level posterior fusions ended in the cervical spine versus those in whom the fusion was extended into the thoracic spine.

STUDY DESIGN

Multicenter retrospective analysis.

OUTCOME MEASURES

Visual analog scale (VAS), Oswestry disability index (ODI), cervical lordosis, C2-C7 sagittal plumbline, T1 slope, and revision rate.

METHODS

We assembled a radiographic and clinical database of patients that had undergone three or more level posterior cervical fusions for degenerative disease from January 2013 to May 2015 at one of four busy spine centers. Only those patients with at least 2 years of postoperative (postop) follow-up were included. Patients were divided into two groups: group I (fusion ending at C6 or C7) and group II (fusion extending into the thoracic spine). All radiographic measurements (cervical lordosis, T1 slope, and C2-C7 sagittal plumbline) were performed by an independent experienced clinical researcher.

RESULTS

Two hundred and sixty-four patient cases were reviewed and sorted into the two outlined groups, Group I (n=168) and Group II (n=96). Demographically, mean age, percentage of females, non-smokers and anterior support were greater in Group II than in Groups I (p<.05). Mean estimated blood loss (EBL), operative time (OR) and length of hospital stay (LOS) were significantly higher in Group II (p<.05). Rate of revision was not clinically or statistically significantly different (p>.05) between Group I (11.1%) and Group II (9.4%). The majority of the revision surgeries occurred between 2 to 5 years postop. A greater number of subjacent degeneration/spondylolisthesis events were noted in Group I compared with Group II (3.6% vs. 1.2%). There were significant improvements in mean clinical outcomes (ie, VAS and ODI) at two years postop in both groups, but there were no statistically significant differences between the groups (p>.05). Mean cervical lordosis at 2 years postop improved in all groups (12.8° vs. 14.1°); however, there was no significant statistical difference in change for mean cervical lordosis (2 weeks vs. 2 year postop) between the two groups. Similary, there were no significant statistical differences in change for mean C2-C7 sagittal plumbline and T1 slope (2 weeks vs. 2 year postop) between the two groups(p>.05).

CONCLUSIONS

Caudal end level did not significantly affect revision rates, patient reported outcomes or radiographic outcomes. Higher EBL, OR, and LOS in group II suggest that, absent focal C7-T1 pathology, extension of posterior cervical fusions into the thoracic spine may not be necessary. Extension of posterior cervical fusions into the thoracic spine may be recommended for higher risk patients with limitations to strong C7 bone anchorage. In others, it is safe to stop at C7.

Crossing the Cervicothoracic Junction During Posterior Cervical Fusion for Myelopathy Is Associated With Superior Radiographic Parameters But Similar Clinical Outcomes

Background

For laminectomy and posterior spinal fusion (LPSF) surgery for cervical spondylotic myelopathy (CSM), the evidence is unclear as to whether fusions should cross the cervicothoracic junction (CTJ).

Objective

To compare LPSF outcomes between those with and without lower instrumented vertebrae (LIV) crossing the CTJ.

Methods

A consecutive series of adults undergoing LPSF for CSM from 2012 to 2018 with a minimum of 12-mo follow-up were identified. LPSF with subaxial upper instrumented vertebrae and LIV between C6 and T2 were included. Clinical and radiographic outcomes were compared.

Results

A total of 79 patients were included: 46 crossed the CTJ (crossed-CTJ) and 33 did not. The mean follow-up was 22.2 mo (minimum: 12 mo). Crossed-CTJ had higher preoperative C2-7 sagittal vertical axis (cSVA) (33.3 ± 16.0 vs 23.8 ± 12.4 mm, P = .01) but similar preoperative cervical lordosis (CL) and CL minus T1-slope (CL minus T1-slope) (P &gt; .05, both comparisons). The overall reoperation rate was 3.8% (crossed-CTJ: 2.2% vs not-crossed: 6.1%, P = .37). In adjusted analyses, crossed-CTJ was associated with superior cSVA (β = –9.7; P = .002), CL (β = 6.2; P = .04), and CL minus T1-slope (β = –6.6; P = .04), but longer operative times (β = 46.3; P = .001). Crossed- and not-crossed CTJ achieved similar postoperative patient-reported outcomes [Visual Analog Scale (VAS) neck pain, VAS arm pain, Nurick Grade, Modified Japanese Orthopedic Association Scale, Neck Disability Index, and EuroQol-5D] in adjusted multivariable analyses (adjusted P &gt; .05). For the entire cohort, higher postoperative CL was associated with lower postoperative arm pain (adjusted Pearson's r –0.1, P = .02). No postoperative cervical radiographic parameters were associated with neck pain (P &gt; .05).

Conclusion

Subaxial LPSF for CSM that crossed the CTJ were associated with superior radiographic outcomes for cSVA, CL, and CL minus T1-slope, but longer operative times. There were no differences in neck pain or reoperation rate.

Complications following posterior cervical decompression and fusion: a review of incidence, risk factors, and prevention strategies

Posterior cervical decompression and fusion (PCF) is a common surgical technique used to treat various cervical spine pathologies. However, there are various complications associated with PCF that can negatively impact patient outcome. We performed a comprehensive literature review to identify the most common complications following PCF using PubMed, Cochrane Database of Systematic Reviews, and Google Scholar. The overall complication rates of PCF are estimated to range from about 15% to 25% in the current literature. The most common immediate complications include acute blood loss anemia, surgical site infection (SSI), C5 palsy, and incidental durotomy; the most common long-term complications include adjacent segment degeneration, junctional kyphosis, and pseudoarthrosis. Three principal mechanisms are thought to contribute to complications. First, higher number of fusion levels, obesity, and more complex pathologies can increase the invasiveness of the planned procedure, thus increase complications. Second, wound healing and arthrodesis may be impaired due to poor blood flow due to various patient factors such as smoking, diabetes, increased frailty, steroid use, and other medical comorbidities. Finally, increased biomechanical stress on the upper instrumented vertebra (UIV) and lowest instrumented vertebra (LIV) may predispose patient to chronic degeneration and result in adjacent level degeneration and/or junctional problems. Reducing the modifiable risk factors pre-operatively can decrease the overall complication rate. Neurologic deficits may be reduced with adequate intraoperative decompression of neural elements. SSI may be reduced with meticulous wound closure that minimizes dead space, drain placement, and the use of intra-wound antibiotics. Careful design of the fusion construct with consideration in spinal alignment and biomechanics can help to reduce the rate of junctional problems. Spine surgeons should be aware of these complications associated with PCF and the corresponding prevention strategies optimize patient outcomes.

Crossing the Cervicothoracic Junction in Cervical Arthrodesis Results in Lower Rates of Adjacent Segment Disease Without Affecting Operative Risks or Patient-Reported Outcomes

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate the risks and benefits of crossing the cervicothoracic junction (CTJ) in cervical arthrodesis.

SUMMARY OF BACKGROUND DATA

Whether the CTJ should be crossed in cervical arthrodesis remains up for debate. Keeping C7 as the distal end of the fusion risks adjacent segment disease (ASD) and can result in myelopathy or radiculopathy. Longer fusions are thought to increase operative risk and complexity but result in lower rates of ASD.

MATERIALS AND METHODS

Patients undergoing cervical spine fusion surgery ending at C7 or T1 with ≥1-year follow-up were included. To evaluate operative risk, estimated blood loss (EBL), operative time, and length of hospital stay were collected. To evaluate patient-reported outcomes (PROs), Neck Disability Index (NDI) and SF-12 questionnaires (PCS12 and MCS12) were obtained at follow-up. Revision surgery data were also obtained.

RESULTS

A total of 168 patients were included and divided into a C7 end-of-fusion cohort (NC7=59) and a T1 end-of-fusion cohort (NT1=109). Multivariate regression analysis adjusting for age, sex, race, surgical approach, and number of levels fused showed that EBL (P=0.12), operative time (P=0.07), and length of hospital stay (P=0.06) are not significantly different in the C7 and T1 end-of-fusion cohorts. Multivariate regression of PROs showed no significant difference in NDI (P=0.70), PCS12 (P=0.23), or MCS12 (P=0.15) between cohorts. Fisher analysis showed significantly higher revision rates in the C7 end-of-fusion cohort (7/59 for C7 vs. 2/109 for T1; odds ratio, 6.4; 95% confidence interval, 1.2-65.1; P=0.01).

CONCLUSIONS

Crossing the CTJ in cervical arthrodesis does not increase operative risk as measured by blood loss, operative time, and length of hospital stay. However, it leads to lower revision rates, likely because of the avoidance of ASD, and comparable PROs. Thus, crossing the CTJ may help prevent ASD without negatively affecting operative risk or long-term PROs.