Revision surgery for failed cervical spine reconstruction: review article

What Is the Evidence Supporting Osteobiologic Use in Revision Anterior Cervical Discectomy and Fusion?

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To analyze the literature and describe the evidence supporting osteobiologic use in revision anterior cervical discectomy and fusion (ACDF) surgery.

METHODS

A systematic search of PubMed/MEDLINE, EMBASE, Cochrane library, and ClinicalTrials.gov databases was conducted for literature reporting the use of osteobiologics in revision ACDF. We searched for studies reporting outcomes of using any osteobiologic use in revision ACDF surgeries (independently of the number of levels) in the above databases.

RESULTS

There are currently no studies in the literature describing the outcome and comparative efficacy of diverse osteobiologic agents in the context of revision ACDF surgery. A majority of the current evidence is based only upon studies involving primary ACDF surgery.

CONCLUSION

The current study highlights the paucity of literature evidence on the role of diverse osteobiologics in revision ACDF, and foregrounds the need for high-quality evidence on this subject.

Incidence of Pseudarthrosis and Subsequent Surgery After Cervical Fusion Surgery: A Retrospective Review of a National Health Care Claims Database

BACKGROUND

Cervical pseudarthrosis is a postoperative adverse event that occurs when a surgically induced fusion fails to establish bone growth connecting the 2 regions. It has both clinical and financial implications and may result in significant patient morbidity; it continues to be one of the leading causes of pain after surgery.

METHODS

A retrospective longitudinal cohort study was performed. Patients in the IBM MarketScan Commercial Claims and Encounters (CCAE) database, 18-64 years old, who underwent elective cervical fusions during 2015-2019 were included. Patients with trauma, infection, or neoplasm were excluded. Patients were followed for 2 years from surgical fusion for occurrence of pseudarthrosis. After pseudarthrosis, subsequent surgery was documented, and cumulative incidence curves, adjusted for patient/procedure characteristics, with 95% confidence intervals (CIs) were generated. Risk factors were evaluated with multivariable Cox regression analysis.

RESULTS

The cohort included 45,584 patients. The 1-year and 2-year incidence of pseudarthrosis was 2.0% (95% CI, 1.9%-2.2%) and 3.3% (95% CI, 3.1%-3.5%), respectively. Factors significantly associated with increased risk of pseudarthrosis were female gender, current/previous substance abuse, previous spinal pain in the cervical/thoracic/lumbar spine, and Elixhauser score ≥5. Factors significantly associated with decreased risk of pseudarthrosis were anterior cervical approach, use of an interbody cage, and 2-level or 3-level anterior instrumentation. The 1-year and 2-year incidence of subsequent surgery in patients with pseudarthrosis was 11.7% (95% CI, 9.6%-13.7%) and 13.8% (95% CI, 11.5%-16.2%), respectively.

CONCLUSIONS

Cervical pseudarthrosis and subsequent surgery still occur at a low rate. Surgical factors such as anterior approach, interbody cage use, and anterior instrumentation may reduce pseudarthrosis risk.

A Novel Local Cancellous Autograft Source for Anterior Cervical Discectomy With Fusion

STUDY DESIGN

Case series.

OBJECTIVES

Successful clinical outcome scores following anterior cervical discectomy and fusion (ACDF) have been correlated with high fusion rate. Published fusion rates using iliac crest bone graft (ICBG) have been shown to be as high as 100% for single-level fusions in some studies; however, there is potential associated morbidity with ICBG harvest. This technical description and preliminary case series assessed the clinical efficacy and results of a novel grafting technique for ACDF.

METHODS

Twelve patients underwent novel grafting technique for ACDF in which autograft was procured from the cervical vertebra adjacent to the operative disk. Patients were followed for 2 years using visual analogue pain scale (VAS) and radiological assessment of fusion.

RESULTS

Patients experienced clinically meaningful reduction of radicular symptoms in the affected arm(s) with an average preoperative VAS score of 5.0 ± 0.8 and an average 2-year postoperative score of 1.108 ± 0.475 (P = .0013). Patients also experienced significant resolution of neck pain with an average preoperative VAS score of 7.1 ± 0.5 and average 2-year postoperative score of 2.708 ± 0.861 (P = .0018). All patients achieved solid fusion by 1 year. There were no major or minor complications noted during follow-up.

CONCLUSIONS

This procedure allows for both autograft harvest and cervical decompression to be performed through a single incision. In this series, this technique eliminated the morbidity associated with autograft harvest from the iliac crest while achieving high fusion rates and without additional technique-related complications.

Treatment of cervical non-union with cervical disc replacement: A case series

Introduction

Cervical disc replacement (CDR) has become prevalent in the treatment of cervical pathology. CDR is an appealing option for several reasons, including improvement of symptoms, preservation of range of motion, and the absence of risk for nonunion – a complication of an anterior cervical decompression and fusion (ACDF) surgery. In this case series, we explore the use of CDR to treat cervical nonunion.

Methods

Four patients, ages 50 to 64, presented to one surgeon with symptomatic cervical nonunion. Three of the four patients possessed risk factors for further nonunion and were therefore considered especially well-suited to a CDR rather than a revision ACDF. X-ray, MRI, and CT were used to confirm the presence of nonunion and to determine the architectural feasibility of replacing the level with a cervical disc arthroplasty. Six total nonunion levels were present in four patients (two levels in two patients and one level in two patients). Each of the nonunion levels was successfully treated with a revision decompression and CDR.

Results

Postoperatively, all four patients experienced improvement of nonunion symptoms. Neck Disability Index improved on average by 75% (preoperative score 51% to postoperative score 13%). Flexion-extension X-rays were available in three patients, which showed an increase in an average range of motion from 2 degrees to 7 degrees at the revised levels.

Conclusion

The series describing four successful cases expands the current literature and provides support for future investigation into CDR as a treatment for cervical nonunion. We propose CDR as a viable option to treat symptomatic cervical nonunion and restore range of motion in patients without significant arthrosis and with preserved endplate architecture.

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Cervical disc replacement as an emerging treatment option for preserving motion

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Four patients with confirmed nonunion successfully received disc replacement.

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All resolved symptoms, measured by NDI, and regained range of motion.

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CDR as viable treatment option for nonunion repair

Comparison of Cost and Perioperative Outcome Profiles for Primary and Revision Posterior Cervical Fusion Procedures

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To compare perioperative outcomes and hospitalization costs between patients undergoing primary or revision posterior cervical discectomy and fusion (PCDF).

SUMMARY OF BACKGROUND DATA

While prior studies found differences in outcomes between primary and revision anterior cervical discectomy and fusion (ACDF), risk, and outcome profiles for posterior cervical revision procedures have not yet been elucidated.

METHODS

Institutional records were queried for cases involving isolated PCDF procedures to evaluate preoperative characteristics and outcomes for patients undergoing primary versus revision PCDF between 2008 and 2016. The primary outcome was perioperative complications, while perioperative and resource utilization measures such as hospitalization length, required stay in the intensive care unit (ICU), direct hospitalization costs, and 30-day emergency department (ED) admissions were explored as secondary outcomes.

RESULTS

One thousand one hundred twenty four patients underwent PCDF, with 218 (19.4%) undergoing a revision procedure. Patients undergoing revision procedures were younger (53.0 vs. 60.5 yrs), but had higher Elixhauser scores compared with the non-revision cohort. Revision cases tended to involve fewer spinal segments (3.6 vs. 4.1 segments) and shorter surgical durations (179.3 vs. 206.3 min), without significant differences in estimated blood loss. There were no significant differences in the overall complication rates (P = 0.20), however, the primary cohort had greater rates of required ICU stays (P = 0.0005) and non-home discharges (P = 0.0003). The revision cohort did experience significantly increased odds of 30-day ED admission (P = 0.04) and had higher direct hospitalization (P = 0.03) and surgical (P < 0.0001) costs.

CONCLUSION

Complication rates, including incidental durotomy, were similar between primary and revision PCDF cohorts. Although prior surgery status did not predict complication risk, comorbidity burden did. Nevertheless, patients undergoing revision procedures had decreased risk of required ICU stay but greater risk of 30-day ED admission and higher direct hospitalization and surgical costs.Level of Evidence: 3.

C2-C3 vertebral disc angle: An analysis of patients with and without cervical spondylotic myelopathy

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To define C2-C3 vertebral disc angle (VDA) in patients with and without cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

C2-C3 VDA is a new radiological index of cervical spine alignment. Recent studies have suggested that high postoperative values are associated with greater mechanical complications in patients with cervical spondylotic myelopathy. However, normative values for patients without myelopathy has yet to be defined.

METHODS

Patients with and without cervical myelopathy between 2017 and 2019 were included. Inclusion criteria were patients above 18 years of age with antero-posterior (AP) and lateral (LAT) cervical X-rays. In the non-myelopathic group, patients were excluded if they had neurological symptoms or deficits, presence of cervical axial pain, previous spinal surgery, or diagnosis of either spondylolisthesis or scoliosis. In the myelopathic group, patients were excluded if they had previous spinal surgery. Radiological indices evaluated include: C2-C3 disc angle, C2-C7 Cobb angle, C7 sagittal vertical axis, T1 slope.

RESULTS

In total, 99 patients without myelopathy and 22 patients with myelopathy were identified and analyzed. In patients without myelopathy, the mean for C2-C3 VDA was 25.9±7.9. For patients with myelopathy, preoperative values were 24.4±10.0 and 27.1±7.9 postoperatively. No statistically significant differences were found between patients with and without myelopathy. C2-C3 disc angle was not correlated with age (R=-0.173).

CONCLUSION

This study did not find statistically significant differences in C2-C3 VDA values between patients with and without cervical myelopathy. This study provides normative data for C2-C3 vertebral disc angle in patients with and without cervical spondylotic myelopathy. Furthermore, C2-C3 vertebral disc angle may be independent from age.

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.

Biomechanical comparison of the angle of inserted screws and the length of anterior cervical plate systems with allograft spacers

BACKGROUND

Comparative studies of the biomechanical effects of plates of varying lengths and different screw insertion angles on allograft spacers are lacking.

METHODS

Finite element model analysis of a previously validated, three-dimensional, intact cervical spinal segment model of C3-6 was conducted in the present study. On the C5-6 segment, anterior discectomy and fusion were performed using allograft spacers and different combinations of anterior plates and screws. The biomechanical characteristics of combinations of short, medium, and maximal length plates with screw insertion angles of 0°, 8°, 16°, and 32° were analyzed.

FINDINGS

In flexion and extension, the risk of allograft spacer subsidence decreased as screw angles increased. Short plates with a screw insertion angle of 32° posed the lowest subsidence risk, similar to medium length plates with a screw insertion angle of 16°, in all motion conditions. The risk of bone yielding increased as plate length increased, but decreased as the screw insertion angle increased.

INTERPRETATION

Short plates with a large screw insertion angle (32°) showed the highest mechanical stability and load sharing of allograft spacers and the lowest risk of screw loosening. Accordingly, we recommend the use of a short plate and large screw insertion angle for anterior cervical discectomy and fusion.

Solid Organ Transplant Is Associated With Increased Morbidity and Mortality in Patients Undergoing One or Two-level Anterior Cervical Decompression and Fusion

STUDY DESIGN

Retrospective database review OBJECTIVE.: The aim of this study was to analyze the implications of solid organ transplant (SOT) on postoperative outcomes following elective one or two-level anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Although SOTs have been associated with increased morbidity, postoperative outcomes in SOT recipients undergoing cervical spinal surgery are not well studied.

METHODS

A retrospective database review of Medicare patients younger than 85 years who underwent an elective one to two-level ACDF from 2006-2013 was conducted. Following our exclusion criteria, patients were then divided into the following groups: those with a prior history of kidney, liver, heart or lung transplant (SOT group) and non-SOT patients. Both groups were compared for hospital length of stay, 90-day major medical complications, 90-day hospital readmission, 1-year surgical site infection (SSI), 1-year revision ACDF, and 1-year mortality.

RESULTS

A total of 992 (0.5%) SOT recipients (1,144 organs) were identified out of 199,288 ACDF patients. SOT recipients had a significantly longer length of stay (2.32 vs. 5.22 days, p<0.001), higher rate of major medical complications (8.2% vs. 4.5%; OR 1.85, 95% CI 1.45-2.33, p<0.001) and hospital readmission (19.5% vs. 7.5%, OR 2.05, 95% CI 1.74-2.41, p<0.001). In addition, SOT patients had increased mortality within one year of surgery (5.8% vs. 1.3%; OR 3.01, 95% CI 2.26-3.94, p<0.001) compared to non-SOT patients. SOT was not independently associated with SSI (OR 1.25, 95% CI 0.85-1.75, p=0.230), and there was no significant difference in revision rate (0.9% vs. 0.5%; OR 1.54, 95% CI 0.73-2.82, p=0.202) between both groups.

CONCLUSION

SOT is independently associated with longer hospital stay, increased rate of major medical complications, hospital readmission and mortality. Spine surgeons should be aware of the higher rates of morbidity and mortality in these patients and take it into consideration when developing patient-specific treatment plans.

LEVEL OF EVIDENCE

3.

Revision surgery in cervical spine

PURPOSE

To report the indications, presurgical planning, operative techniques, complications for making decisions in cervical revision surgery (CRS).

METHODS

Hundred and two patients underwent CRS over a four-year period. Epidemiological data, the type of first surgery, CRS surgical techniques and complications were retrospectively evaluated. Pain and neurological symptoms were assessed according to the validated Odom criteria. CRS indications were classified into five categories: adjacent segment disease (ASD), infection (INF), implant failure-pseudarthrosis (IFP), non-infectious complication, and deformity. Patients were classified into three groups, according to the approach of the index procedure: anterior, posterior, or 360°.

RESULTS

The mean patient age was 63 years (59% males). ASD (40%), INF (23%), and IFP (22%) were observed in 85% of patients. CRS was performed with the same approach that was used in the index procedure in 64% of the anterior group and in 83% of the posterior group. In the 360° group, 64% of CRSs was performed with a posterior access. The early complication rate was 4.9%. The outcome was excellent in 19 patients (19%), good in 37 patients (36%), satisfactory in 27 patients (26%), and poor in six patients (6%). Thirteen patients (13%) were lost to follow-up. No implants failed radiologically or required surgical revision.

CONCLUSIONS

CRS required painstaking planning and mastery of a variety of surgical techniques. The results were rewarding in half and satisfactory in a quarter of the patients. The complication rate was lower than expected. In the most complex cases, referral to a specialized center is recommended. These slides can be retrieved under Electronic Supplementary Material.

Cervical Interfacet Spacers to Promote Indirect Decompression and Enhance Fusion in Degenerative Spine: A Review

BACKGROUND

Among the posterior techniques, the use of cervical interfacet spacers (CISs) represents a promising technology whose potentialities are still being studied. The purpose of the present review was to assess the available data on CISs.

METHODS

A search on PubMed was performed. The search terms were "cervical interfacet spacers," "facet spacers," "DTRAX facet system," "Goel facet spacer," "pseudarthrosis," "cervical lordosis," "iatrogenic kyphosis," "cervical foraminal decompression," "cervical biomechanics," "atlantoaxial instability," and "subaxial instability."

RESULTS

Mechanical studies have shown that stand-alone CISs promoted stiffness in all directions, except for extension. Foraminal distraction was recorded in 86% of the cases. Clinical studies have shown that the use of CISs could promote successful arthrodesis, given the large surface area affected by fusion and decreasing the need for autografts. The effectiveness for the treatment of radiculopathy has been confirmed by several clinical studies. In a series of 154 levels of implanted CISs, no evidence of significant loss of cervical lordosis was identified. CISs could help in enhancing fusion in C1-C2 fixation.

CONCLUSIONS

Biomechanical studies on specimens showed a positive trend in increasing stiffness of the cervical spine, despite some controversial results. In clinical studies, facet distraction was shown to be a safe and valid option for clinical indirect decompression, although longer follow-up is required for confirmation. No evidence of the loss of cervical lordosis has been recorded. The long-term effects and CIS use in revision procedures as adjuvant implants to treat pseudarthrosis or atlantoaxial instability are currently under investigation, and further studies are needed.

Overpowering the Previously Posterior Instrumented Cervical Spine With Cage-Assisted Anterior Cervical Discectomy and Fusion: A Cadaveric Study

PURPOSE

Cervical spines previously posteriorly instrumented and fused with a kyphotic deformity represent a surgical challenge. Current treatment strategies include C7 pedicle subtraction osteotomy or a posterior-anterior-posterior approach, which carry the risk of significant complications. The objective of this study was to attempt to achieve lordosis with multiple anterior cervical discectomy and fusion (ACDF) cages to overpower the posterior instrumentation.

METHODS

Four adult cadaveric specimens were selected and underwent C3-C7 posterior laminectomy with posterior instrumentation in a kyphotic alignment using a 3.5-mm titanium screw-rod system. Next, ACDF from C3 to C7 was performed with 15° lordotic cages to restore cervical lordosis. Posterior instrumentation was then inspected for failure. Fluoroscopic images were obtained to calculate total construct lordosis and change in segmental lordosis. CT scans were obtained after ACDF to assess for loosening, instrumentation failure, endplate damage, or impaction. Bone mineral density was calculated on CT scans.

RESULTS

Age ranged from 59 to 82, and all specimens were male. No gross instrumentation failure was observed. Mean pre-ACDF lordosis between C3 and C7 was 0° (-5° to 5°). Post-ACDF lordosis increased to 37° (35°-38°). Mean segmental lordosis achieved with no endplate destruction was 13.1° (8°-17°). T scores for the cadavers were -0.5, -0.5, -3.2, and -5.1. Two levels of impaction were observed (12.5%). Failure of bone screw interface occurred in the cadaver, with a T score of -5.1 in the middle of the construct.

CONCLUSION

Our study demonstrates the validity of overpowering posterior instrumentation through multiple level ACDF with lordotic cages. This may obviate the need to perform posterior-anterior-posterior procedures.

LEVEL OF EVIDENCE

Level III.

Cost-utility of revisions for cervical deformity correction warrants minimization of reoperations

Background

Cervical deformity (CD) surgery has become increasingly more common and complex, which has also led to reoperations for complications such as distal junctional kyphosis (DJK). Cost-utility analysis has yet to be used to analyze CD revision surgery in relation to the cost-utility of primary CD surgeries. The aim of this study was to determine the cost-utility of revision surgery for CD correction.

Methods

Retrospective review of a multicenter prospective CD database. 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 (CBVA) >25°. Quality-adjusted life year (QALY) were calculated by EuroQol Five-Dimensions questionnaire (EQ-5D) and Neck Disability Index (NDI) mapped to SF-6D index and utilized a 3% discount rate to account for residual decline to life expectancy (men: 76.9 years, women: 81.6 years). Medicare reimbursement at 30 days assigned costs for index procedures (9+ level posterior fusion, 4-8 level posterior fusion with anterior fusion, 2-3 level posterior fusion with anterior fusion, 4-8 level anterior fusion) and revision fusions (2-3 level, 4-8 level, or 9+ level posterior refusion). Cost per QALY gained was calculated.

Results

Eighty-nine CD patients were included (61.6 years, 65.2% female). CD correction for these patients involved a mean 7.7±3.7 levels fused, with 34% combined approach surgeries, 49% posterior-only and 17% anterior-only, 19.1% three-column osteotomy. Costs for index surgeries ranged from $20,001-55,205, with the average cost for this cohort of $44,318 and cost per QALY of $27,267. Eleven revision surgeries (mean levels fused 10.3) occurred up to 1-year, with an average cost of $41,510. Indications for revisions were DJK (5/11), neurologic impairment [4], infection [1], prominent/painful instrumentation [1]. Average QALYs gained was 1.62 per revision patient. Cost was $28,138 per QALY for reoperations.

Conclusions

CD revisions had a cost of $28,138 per QALY, in addition to the $27,267 per QALY for primary CD surgeries. For primary CD patients, CD surgery has the potential to be cost effective, with the caveats that a patient livelihood extends long enough to have the benefits and durability of the surgery is maintained. Efforts in research and surgical technique development should emphasize minimization of reoperation causes just as DJK that significantly affect cost utility of these surgeries to bring cost-utility to an acceptable range.

Patient-Reported Outcomes and Costs Associated With Revision Surgery for Degenerative Cervical Spine Diseases

STUDY DESIGN

A retrospective review of a prospective database.

OBJECTIVE

The aim of this study was to determine cost and outcomes of revision cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Revision rates for cervical spine surgery are steadily increasing. It is important to counsel patients on expected results following a revision procedure. However, outcomes and cost of these procedures are poorly defined in the literature.

METHODS

Patients undergoing revision cervical spine surgery at a single institution were included between October 2010 and January 2016 in a prospective registry database. Patients were divided into three cohorts depending on their etiology for revision, including recurrent disease, pseudoarthrosis, or adjacent segment disease. Patient-reported outcomes (PROs), including Neck Disability Index (NDI), EuroQol-5D (EQ-5D), modified Japanese Orthopaedic Association (mJOA) score, numeric rating scale-neck pain (NRS-NP), and numeric rating scale-arm pain (NRS-AP), were measured at baseline and 12 months following revision surgery. Mean costs at 12 months following revision surgery were also calculated. Satisfaction was determined by the NASS patient satisfaction index. Variables were compared using Student t test.

RESULTS

A total of 115 patients underwent cervical revision surgery for recurrent disease (n = 21), pseudoarthrosis (n = 45), and adjacent segment disease (n = 49). There was significant improvement in all patient-reported outcomes at 12 months following surgery regardless of etiology (P < 0.0001). Total cost of revision surgery ranged between 21,294 ± 8614 and 23,914 ± 15,396 depending on pathology. No significant differences were seen between costs among different revision groups (P = 0.53). Satisfaction was met in 75.5% to 85.7% (P = 0.21) of patients depending on the etiology of the revision need. Complication rates were between 4% and 9%.

CONCLUSION

This is one of the first studies to determine costs and outcome measures in the setting of cervical spine revision surgery. On the basis of our analysis, a majority of patients can expect to receive some benefit by 12 months and are satisfied with their procedure.

LEVEL OF EVIDENCE

4.

Cervical sagittal alignment after different anterior discectomy procedures for single-level cervical degenerative disc disease: randomized controlled trial

Background

The effect of anterior cervical discectomy without fusion (ACD), ACD with fusion by stand-alone cage (ACDF) or with arthroplasty (ACDA) on cervical sagittal alignment is not known and is the subject of this study.

Methods

A total of 142 adult patients with single-level cervical disease were at random allocated to different procedures: ACD (45), ACDF (47) and ACDA (50). Upright cervical spine radiographs were obtained. Angles of the involved angle and the angle between C2 and C7 were determined.

Results

After a mean follow-up of 25.4 ± 18.4 months, the angles of the involved level comparing ACD with ACDA and ACD with ACDF were different, reaching statistical significance. However, the angle between C2 and C7 did not differ between groups or between preoperative values and at follow-up.

Conclusions

Irrespective of the technique used for anterior cervical discectomy for single-level degenerative disc disease, the alignment of the cervical spine is unaltered.

Posterior Cervical Fusion Using Cervical Interfacet Spacers in Patients With Symptomatic Cervical Pseudarthrosis

BACKGROUND

Posterior cervical fusion with cervical interfacet spacer (CIS) is a novel allograft technology offering the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion by placing the allograft in compression.

OBJECTIVE

To analyze the clinical and radiological outcomes after posterior cervical fusion with CIS in patients with symptomatic anterior cervical pseudarthroses.

METHODS

Medical records of patients who underwent posterior cervical fusion with CIS for symptomatic pseudarthrosis after anterior cervical diskectomy and fusion were reviewed. Standardized outcome measures such as visual analog scale (VAS) score for neck and arm pain, Neck Disability Index (NDI), and upright lateral cervical radiographs were reviewed.

RESULTS

There were 19 patients with symptomatic cervical pseudarthrosis. Preoperative symptoms included refractory neck or arm pain. The average follow-up was 20 months (range, 12-56 months). There was improvement in VAS score for neck pain (P < .004), radicular arm pain (P < .007), and NDI score (P < .06) after surgery, with 83%, 72%, and 67% of patients showing improvement in their VAS neck pain, VAS arm pain, and NDI scores, respectively. Fusion rate was high, with fusion occurring at all levels treated for pseudarthrosis. There was a small improvement in cervical lordosis (mean difference, 2 ± 5.17°; P = .09) and slight worsening of C2-7 sagittal vertical axis after surgery (mean difference, 1.89 ± 7.87 mm; P = .43).

CONCLUSION

CIS provides an important fusion technique, allowing placement of an allograft in compression for posterior cervical fusion in patients with anterior cervical pseudarthroses. Although there was improvement in clinical outcome measures after surgery, placement of CIS had no clinically significant impact on cervical lordosis and C2-7 sagittal vertical axis.