Same-day spine surgery at an ambulatory surgical center versus hospital outpatient department

J Neurosurg Spine 44:835–846, 2026

This clinical study compares safety, complications, and patient-reported outcomes for same-day anterior cervical arthrodesis/arthroplasty and lumbar decompression performed in ambulatory surgical centers (ASC) versus hospital outpatient departments (HOPD) using a propensity-matched statewide registry. Primary outcomes included complication rates, return to OR, ED visits, and readmissions; secondary outcomes assessed PROMs and return-to-work at 90 days and 1 year.

Matched analysis of 3,351 lumbar decompressions and 806 anterior cervical procedures found no differences in PROs between ASC and HOPD, comparable safety for anterior cervical surgery, but a slightly higher rate of return to OR—driven by reherniation—for lumbar decompression performed in ASCs. Authors recommend future cost-effectiveness and patient-selection research.

Objective Compare safety and outcomes of same-day discharge anterior cervical arthrodesis/arthroplasty (1–2 levels) and lumbar decompression performed in an ambulatory surgical center (ASC) versus a hospital outpatient department (HOPD).

Design/Data source Retrospective, propensity-matched comparative cohort analysis using the statewide Michigan Spine Surgery Improvement Collaborative (MSSIC) registry for cases from Jan 1, 2021 to Jun 30, 2023.

Matching approach HOPD:ASC cohorts matched 4:1 using BMI, ASA class, and number of operative levels to improve comparability and power.

Primary outcomes Assessed any complication, return to operating room (OR) within 90 days, and ED visit or readmission within 30 and 90 days; secondary outcomes included PROs at 90 days/1 year and return to work.

Sample size (matched) Included 3351 lumbar decompressions (2679 HOPD, 672 ASC) and 806 anterior cervical cases (644 HOPD, 162 ASC).

Cervical results No significant ASC vs HOPD differences for complications, PROs at 90 days or 1 year, or return to work at 90 days or 1 year (p > 0.05).

Lumbar results (safety) ASC had higher rates of any complication (8% vs 5.5%) and return to OR (4.9% vs 2.1%) than HOPD in univariate analysis, and this persisted in multivariate analysis (IRR 1.5 for any complication; IRR 2.3 for return to OR).

Lumbar results (driver & outcomes) Elevated return-to-OR risk in ASC was driven primarily by lumbar reherniation requiring reoperation (3.2% ASC vs 1.0% HOPD), while PROs at 90 days and 1 year were otherwise similar between settings.

Complications associated with anterior cervical spine surgery: A systematic review of literature

Brain and Spine 6 (2026) 105897

This systematic review examines complications following anterior cervical spine surgery, quantifying incidence rates across studies and identifying major risks such as dysphagia, adjacent segment disease, recurrent laryngeal nerve palsy, infection, pseudarthrosis, esophageal perforation, hematoma, and vertebral artery injury. It synthesizes data from 116 studies (1989–2024) and assesses study quality using the Newcastle–Ottawa Scale.

The review highlights key risk factors—multilevel procedures, revision surgery, OPLL, smoking, older age, and surgeon experience—and emphasizes the importance of preoperative planning, patient selection, standardized prospective monitoring, and timely management to minimize morbidity and guide informed consent and long-term surveillance.

Aim Quantify frequency, causes, and outcomes of complications associated with anterior cervical spine surgery.

Methods Systematic review following PRISMA; searched CINAHL Plus, MEDLINE, PubMed, Scopus, and EMBASE for English-language studies (1989–2024) in adults; quality assessed with the Newcastle Ottawa Scale.

Evidence base 326 records screened; 116 studies included; study quality ranged from 3/9 to 9/9 on NOS, with frequent weaknesses in external control selection and cohort comparability.

Most common complication (dysphagia) Reported incidence varied widely (2.3%–87.5%); overall rate across all included dysphagia studies was 13%, with higher pooled incidence in prospective vs retrospective cohorts (53.7% vs 12.7%).

Other key complications (ranges) Adjacent segment disease 0.4%–32%; recurrent laryngeal nerve palsy 0.1%–9%; infection 0.39%–8.5%; pseudarthrosis 0.25%–31%; esophageal perforation 0.1%–0.45%; vertebral artery injury 0.3%–7.7%; Horner’s syndrome 0.06%–0.45%; graft failure 2.7%–35.5%; CSF leak 0%–1%; postoperative hematoma 0.21%–7%; new/worsening neurological deficits 0.37%–3.3.

Risk factors (higher complication rates) Multilevel disease, revision surgery, and ossification of the posterior longitudinal ligament (OPLL) were associated with increased complications.

Volume–outcome effect Greater surgeon experience and higher case volume were consistently associated with lower complication rates.

Prevention emphasis Reducing complications depends on thorough preoperative planning, careful patient selection, and proper surgical technique.

Does the Presence of Preoperative Myelomalacia Impact Outcomes Following ACDF?

Spine 2025;50:1539–1546

This retrospective cohort study examines whether preoperative cervical myelomalacia on MRI influences patient-reported outcomes after anterior cervical discectomy and fusion (ACDF) in 518 adults. Results show similar modified JOA (mJOA) recovery between groups, with myelomalacia not independently predicting worse mJOA up to one year postoperatively.

Secondary findings reveal myelomalacia patients had lower baseline pain/disability and less frequent NDI MCID achievement, but multivariable analysis attributed those differences to baseline scores, smoking, and demographics rather than myelomalacia itself. Multilevel myelomalacia correlated with worse baseline mJOA but did not independently affect long-term improvement.

• Preoperative Myelomalacia: Presence of myelomalacia on MRI before anterior cervical discectomy and fusion (ACDF) in patients with mild-moderate myelopathy does not predict worse postoperative mJOA scores or overall patient-reported outcomes at any time point up to one year after surgery.

• Functional Outcomes: Both patients with and without preoperative myelomalacia achieve similar improvements in functional outcomes (mJOA), with no significant difference in the likelihood of reaching the minimum clinically important difference (MCID) for mJOA.

• Neck Disability Index (NDI): Patients with myelomalacia less commonly achieve MCID for NDI at one year, but this is attributable to less severe baseline symptoms and higher rates of current smoking, not the presence of myelomalacia itself.

• Multilevel Myelomalacia: Patients with two or more levels of myelomalacia have worse preoperative mJOA scores but show greater short-term improvement, resulting in similar one-year outcomes compared to single-level myelomalacia; preoperative severity, not the extent of myelomalacia, predicts improvement.

• Baseline Differences: Patients with myelomalacia tend to have lower baseline pain and disability, possibly due to earlier surgical intervention prompted by MRI findings rather than symptom severity.

• Other Patient-Reported Outcomes: Myelomalacia patients may have better physical component scores (SF-12 PCS) and lower neck pain (VAS neck) at one year, but these differences are small and likely reflect baseline characteristics rather than effects of myelomalacia.

• Prognostic Value: Myelomalacia seen on MRI should not be used as a binary prognostic indicator for surgical outcomes in mild-moderate myelopathy; clinical decision-making should consider baseline function and other patient factors.

• Research Implications: Further studies are needed to clarify the impact of myelomalacia severity, chronicity, and timing on outcomes, especially in patients with more severe myelopathy or more extensive cord signal changes

Which interbody device minimized nonunion, subsidence, and reoperation after anterior cervical discectomy and fusion?

J Neurosurg Spine 43:453–463, 2024

This meta-analysis found that allograft spacers in anterior cervical discectomy and fusion (ACDF) result in lower nonunion and revision rates compared to PEEK cages, with no significant difference in subsidence risk. Allograft offers enhanced fusion and minimizes revision without increasing subsidence.

• Allograft and PEEK cages are the most commonly used interbody spacers in anterior cervical discectomy and fusion (ACDF), replacing autograft due to lower donor site morbidity.

• This meta-analysis included 10 studies with 1462 patients comparing allograft and PEEK cages for ACDF, analyzing nonunion, subsidence, and reoperation rates.

• Allograft showed a significantly lower rate of nonunion than PEEK cages (OR 0.33, p = 0.01), indicating better fusion outcomes.

• Reoperation due to nonunion was significantly higher with PEEK cages compared to allograft (OR 0.28, p < 0.01), but overall reoperation rates for any cause were not significantly different.

• No significant difference was found in the incidence or amount of subsidence between allograft and PEEK cages.

• Allograft’s osteoconductive properties likely contribute to its higher fusion rate, while PEEK cages may lead to fibrous interface formation, reducing solid fusion.

• Meta-regression showed no significant effect of smoking, age, or number of fused levels on nonunion rates.

• Conclusion: Allograft is advantageous over PEEK cages in ACDF due to higher fusion rates and lower revision risk, without increasing subsidence

Comparison of outcomes between cervical disc arthroplasty and anterior cervical discectomy and fusion for the treatment of cervical spondylotic myelopathy

J Neurosurg Spine 42:705–717, 2025

This systematic review and meta-analysis evaluates the outcomes of cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) in treating cervical spondylotic myelopathy (CSM). Based on 12 randomized controlled trials including 2,612 patients, the study found that CDA shows superior clinical effectiveness and a more favorable safety profile than ACDF. Neck pain improvement (VAS) with CDA was clinically meaningful within the first postoperative year. CDA also had lower reoperation rates and reduced incidence of adjacent segment disease (ASD), although with slightly longer operative times. Further high-quality, large-scale trials are needed to confirm these findings.
Key Points
• • Objective: Compare the efficacy and safety of CDA vs. ACDF in CSM patients through meta-analysis.
• • Methods: 12 RCTs with 2,612 patients (1,464 CDA, 1,148 ACDF); outcomes included NDI, VAS, ROM, SF-36, complications, and reoperations.
• • Overall success: Higher in CDA group (RR 1.21; p = 0.004).
• • Neck pain (VAS): Significantly improved in CDA up to 12 months post-op; clinically meaningful.
• • Arm pain (VAS): Slight improvement at 3 and 12 months; not clinically significant.
• • NDI scores: Statistically better in CDA, though often below MCID thresholds.
• • ROM: Better preserved in CDA; data limited and heterogeneous.
• • Quality of life (SF-36): No significant differences between groups.
• • Operative time: Longer in CDA (MD 18.75 min; p < 0.00001).
• • Complications: Similar blood loss and adverse event rates; lower ASD and reoperation rates in CDA.
• • Limitations: Limited CSM-specific data, inconsistent surgical protocols, and risk of bias in several trials.
• • Conclusion: CDA offers better early clinical outcomes and fewer mechanical complications than ACDF, but broader validation is needed.

Could indirect decompression occur for cord compression by the ligamentum flavum with anterior cervical discectomy and fusion?

J Neurosurg Spine 42:100–109, 2025

Cord compression by the ligamentum flavum (CCLF) has been reported to adversely affect the clinical outcomes of anterior cervical discectomy and fusion (ACDF). While indirect decompression does occur for foraminal stenosis with ACDF, whether ACDF could improve CCLF with the distraction of disc space remains unclear. This study aimed to identify 1) whether indirect decompression occurs for CCLF with ACDF, and 2) risk factors that hinder the improvement of CCLF.

METHODS This retrospective cohort study included 119 patients who underwent ACDF for the treatment of cervical myelopathy and CCLF was detected on preoperative MRI. Patients who demonstrated improvement in CCLF grade after ACDF were included in the improved group, while those who did not show improvement were classified as the unimproved group. Patient characteristics, cervical sagittal parameters, neck and arm pain visual analog scale score, and Japanese Orthopaedic Association (JOA) score were assessed. A comparison between the improved and unimproved groups was performed. Regression analyses were performed to identify factors associated with CCLF grade improvement.

RESULTS Overall, 58.0% (69/119) of patients showed improvement in CCLF grade after ACDF. CCLF grade did not improve in the remaining 42.0% (50/119) of patients, and 3.4% (4/119) of patients experienced aggravation of CCLF after ACDF. Preoperative spondylolisthesis (OR 0.252, 95% CI 0.090–0.711; p = 0.009) and greater segmental lordosis 3 months postoperatively (OR 0.835, 95% CI 0.731–0.953; p = 0.008) were the factors that hindered the improvement of CCLF after ACDF. Furthermore, patients with higher pre- or postoperative CCLF grades showed significantly less improvement in JOA score 2 years postoperatively.

CONCLUSIONS Indirect decompression for CCLF with ACDF is not reliable because 42.0% of patients did not demonstrate improvement in CCLF grade after the operation. Preoperative spondylolisthesis and postoperative increased segmental lordosis were risk factors for failure of CCLF improvement. Both pre- and postoperative higher CCLF grades were associated with poor neurological recovery 2 years postoperatively.

 

Radiographic Risk Factors for Adjacent Segment Disease Following Anterior Cervical Discectomy and Fusion (ACDF): A Systematic Review and Meta-Analysis

Global Spine Journal 2024, Vol. 14(7) 2183–2200

Study Design: Systematic review and meta-analysis.

Objectives: To assess the radiographic risk factors for adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine pathologies.

Methods: PubMed, Embase and the Cochrane Library databases were searched up to December 2023. The primary inclusion criteria were degenerative spinal conditions treated with ACDF, comparing radiological parameters in patients with and without postoperative ASD. The radiographic parameters included intervertebral disc height, cervical sagittal alignment, sagittal segmental alignment, range of motion, segmental height, T1 slope, sagittal vertical axis (SVA), thoracic inlet angle (TIA), and plate to disc distance (PPD). Risk of bias was assessed for all studies. The Cochrane Review Manager was utilized to perform the meta-analysis.

Results: From 7044 articles, 13 retrospective studies were included in the final analysis. Three studies had “not serious” bias and the other 10 studies had serious or very serious bias. The total number of patients in the included studies was 1799 patients. Five studies included single-level ACDF, 2 studies included multi-level ACDF, and 6 studies included single or multi-level ACDF. On meta-analysis, the significant risk factors associated with ASD development were reduced postoperative cervical lordosis (mean difference [MD] = 3.35°, P = .002), reduced last-follow-up cervical lordosis (MD = À3.02°, P = .0003), increased preoperative to postoperative cervical sagittal alignment change (MD = À3.68°, P = .03), and the presence of developmental cervical canal stenosis (Odds ratio [OR] = 4.17, P < .001).

Conclusions: Decreased postoperative cervical lordosis, greater change in cervical sagittal alignment and developmental cervical canal stenosis were associated with an increased risk of ASD following ACDF.

Comparing posterior cervical foraminotomy with anterior cervical discectomy and fusion in radiculopathic patients: an analysis from the Quality Outcomes Database

J Neurosurg Spine 41:56–68, 2024

OBJECTIVE The objective of this study was to compare clinical and patient-reported outcomes (PROs) between posterior foraminotomy and anterior cervical discectomy and fusion (ACDF) in patients presenting with cervical radiculopathy.

METHODS The Quality Outcomes Database was queried for patients who had undergone ACDF or posterior foraminotomy for radiculopathy. To create two highly homogeneous groups, optimal individual matching was performed at a 5:1 ratio between the two groups on 29 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, underlying pathologies, and levels treated). Outcomes of interest were length of stay, reoperations, patient-reported satisfaction, increase in EQ-5D score, and decrease in Neck Disability Index (NDI) scores for arm and neck pain as long as 1 year after surgery. Noninferiority analysis of achieving patient satisfaction and minimal clinically important difference (MCID) in PROs was performed with an accepted risk difference of 5%.

RESULTS A total of 7805 eligible patients were identified: 216 of these underwent posterior foraminotomy and were matched to 1080 patients who underwent ACDF. The patients who underwent ACDF had more underlying pathologies, lower EQ-5D scores, and higher NDI and neck pain scores at baseline. Posterior foraminotomy was associated with shorter hospitalization (0.5 vs 0.9 days, p < 0.001). Reoperations within 12 months were significantly more common among the posterior foraminotomy group (4.2% vs 1.9%, p = 0.04). The two groups performed similarly in PROs, with posterior foraminotomy being noninferior to ACDF in achieving MCID in EQ-5D and neck pain scores but also having lower rates of maximal satisfaction at 12 months (North American Spine Society score of 1 achieved by 65.2% posterior foraminotomy patients vs 74.6% of ACDF patients, p = 0.02).

CONCLUSIONS The two procedures were found to be offered to different populations, with ACDF being selected for patients with more complicated pathologies and symptoms. After individual matching, posterior foraminotomy was associated with a higher reoperation risk within 1 year after surgery compared to ACDF (4.2% vs 1.9%). In terms of 12-month PROs, posterior foraminotomy was noninferior to ACDF in improving quality of life and neck pain. The two procedures also performed similarly in improving NDI scores and arm pain, but ACDF patients had higher maximal satisfaction rates.

Early Voice and Swallowing Disturbance Incidence and Risk Factors After Revision Anterior Cervical Discectomy and Fusion Using a Multidisciplinary Surgical Approach

Neurosurgery 94:444–453, 2024

Dysphagia and vocal cord palsy (VCP) are common otolaryngological complications after revision anterior cervical discectomy and fusion (rACDF) procedures. Our objective was to determine the early incidence and risk factors of VCP and dysphagia after rACDF using a 2-team approach.

METHODS: Single-institution, retrospective analysis of a prospectively collected database of patients undergoing rACDF was enrolled from September 2010 to July 2021. Of 222 patients enrolled, 109 patients were included in the final analysis. All patients had prior ACDF surgery with planned revision using a single otolaryngologist and single neurosurgeon. MD Anderson Dysphagia Inventory and fiberoptic endoscopic evaluation of swallowing (FEES) were used to assess dysphagia. VCP was assessed using videolaryngostroboscopy.

RESULTS: Seven patients (6.7%) developed new postoperative VCP after rACDF. Most cases of VCP resolved by 3 months postoperatively (mean time-to-resolution 79 ± 17.6 days). One patient maintained a permanent deficit. Forty-one patients (37.6%) reached minimum clinically important difference (MCID) in their MD Anderson Dysphagia Inventory composite scores at the 2-week follow-up (MCID decline of ≥6), indicating new clinically relevant swallowing disturbance. Forty-nine patients (45.0%) had functional FEES Performance Score decline. On univariate analysis, there was an association between new VCPs and the number of cervical levels treated at revision (P = .020) with long-segment rACDF (≥4 levels) being an independent risk factor (P = .010). On linear regression, there was an association between the number of levels treated previously and at revision for FEES Performance Score decline (P = .045 and P = .002, respectively). However, on univariate analysis, sex, age, body mass index, operative time, alcohol use, smoking, and individual levels revised were not risk factors for reaching FEES Performance Score decline nor MCID at 2 weeks postoperatively.

CONCLUSION: VCP is more likely to occur in long-segment rACDF but is often temporary. Clinically relevant and functional rates of dysphagia approach 37% and 45%, respectively, at 2 weeks postoperatively after rACDF.

Effect of workers’ compensation status on pain, disability, quality of life, and return to work after anterior cervical discectomy and fusion: a 1-year propensity score–matched analysis

J Neurosurg Spine 39:822–830, 2023

Patients with workers’ compensation (WC) claims are reported to demonstrate poorer surgical outcomes after lumbar spine surgery. However, outcomes after anterior cervical discectomy and fusion (ACDF) in WC patients remain debatable. The authors aimed to compare outcomes between a propensity score–matched population of WC and non-WC patients who underwent ACDF.

METHODS Patients who underwent 1- to 4-level ACDF were retrospectively reviewed from the prospectively maintained Quality Outcomes Database (QOD). After propensity score matching, 1-year patient satisfaction, physical disability (Neck Disability Index [NDI]), pain (visual analog scale [VAS]), EQ-5D, and return to work were compared between WC and non-WC cohorts.

RESULTS A total of 9957 patients were included (9610 non-WC and 347 WC patients). Patients in the WC cohort were significantly younger (50 ± 9.1 vs 56 ± 11.4 years, p < 0.001), less educated, and were more frequently male, non-Caucasian, and active smokers (29.1% vs 18.1%, p < 0.001), with greater baseline VAS and NDI scores and poorer quality of life (p < 0.001). One-year postoperative improvements in VAS, NDI, EQ-5D, and return-to-work rates and satisfaction were all significantly worse for WC compared with non-WC patients. After adjusting for baseline differences via propensity score matching, WC versus non-WC patients continued to demonstrate worse 3- and 12-month VAS neck pain and NDI (p = 0.010), satisfaction (χ 2 = 4.03, p = 0.045), and delayed return to work (9.3 vs 5.7 weeks, p < 0.001).

CONCLUSIONS WC status was associated with greater 1-year residual disability and axial pain along with delayed return to work, without any difference in quality of life despite having fewer comorbidities and being a younger population. Further studies are needed to determine the societal impact that WC claims have on healthcare delivery in the setting of ACDF.

Comparison of clinical outcomes between cervical disc arthroplasty and anterior cervical discectomy and fusion for the treatment of single-level cervical spondylosis: a 10-year follow-up study

The Spine Journal 23 (2023) 361−368

The theoretical advantage of cervical disc arthroplasty includes preserved motion at the cervical level, which may reduce degeneration of the adjacent segments. The long-term follow-up results are still controversial.

PURPOSE: The present study aimed to retrospectively study the long-term efficacy and complications of cervical disc arthroplasty using a single commercially-available device in a single center.

STUDY DESIGN: This was a propensity-score matched cohort study.

PATIENT SAMPLE: This study enrolled 148 single-level cervical degenerative disease patients from January 2009 to March 2012. After 1:1 propensity score matching, 39 patients remained in the ACDF or ACDR groups.

OUTCOME MEASURES: The outcome measures were neurological functions (Neck Disability Index (NDI) and Japan Orthopedic Association (JOA) scores), radiographic evaluations (cervical curvature, operative segment range of motion, degenerative condition of adjacent segments, heterotopic ossification (HO) of the surgical segment), and complications.

METHODS: NDI and JOA scores were used to evaluate patient neurological functions. Cervical curvature (C2-C7 Cobb angle) and operative segment range of motion (ROM) were compared between the two groups. Grading criteria for osteophyte formation were used to evaluate the degenerative condition of adjacent segments. HO after ACDR was graded according to the McAfee grading method.

RESULTS: The average follow-up time was 119.3 §17.2 months. Satisfactory improvements in neurological function were obtained for both the ACDR and ACDF groups. There were no significant differences in VAS or NDI scores between the two groups. In the ACDR group, the ROM of the operative segment increased from 6.7 §4.3˚ before the operation to 8.9 §3.5˚ on the second day after the operation (p<.001). The ROM of the operative segment was 8.1 §4.0˚ at the 1-year follow-up, 7.2 §3.6˚ at the 2-year follow-up, 5.7 §4.5˚ at the 5-year follow-up and 4.3 §3.9˚ at the last follow-up. ASD was more likely to develop in the caudal adjacent segments and progressed with the follow-up time. At the last follow-up, HO was present in 27 patients (69.23%), while high-grade HO (McAfee scores III and IV) was detected in 6 patients (15.38%).

CONCLUSIONS: Through nearly 10 years of follow-up, ACDR was as effective as ACDF for treating single-level degenerative cervical disc disease. However, HO and the role of ACDR in the protection of ASD remains to be further observed and followed up.

Comparison of anterior cervical discectomy and fusion versus artificial disc replacement for cervical spondylotic myelopathy: a meta-analysis

J Neurosurg Spine 37:569–578, 2022

Anterior cervical discectomy and fusion (ACDF) has long been regarded as a gold standard in the treatment of cervical myelopathy. Subsequently, cervical artificial disc replacement (c-ADR) was developed and provides the advantage of motion preservation at the level of the intervertebral disc surgical site, which may also reduce stress at adjacent levels. The goal of this study was to compare clinical and functional outcomes in patients undergoing ACDF with those in patients undergoing c-ADR for cervical spondylotic myelopathy (CSM).

METHODS A systematic literature review and meta-analysis were performed using the Embase, PubMed, and Cochrane Central Register of Controlled Trials databases from database inception to November 21, 2021. The authors compared Neck Disability Index (NDI), SF-36, and Japanese Orthopaedic Association (JOA) scores; complication rates; and reoperation rates for these two surgical procedures in CSM patients. The Mantel-Haenszel method and varianceweighted means were used to analyze outcomes after identifying articles that met study inclusion criteria.

RESULTS More surgical time was consumed in the c-ADR surgery (p = 0.04). Shorter hospital stays were noted in patients who had undergone c-ADR (p = 0.04). Patients who had undergone c-ADR tended to have better NDI scores (p = 0.02) and SF-36 scores (p = 0.001). Comparable outcomes in terms of JOA scores (p = 0.24) and neurological success rate (p = 0.12) were noted after the surgery. There was no significant between-group difference in the overall complication rates (c-ADR: 18% vs ACDF: 25%, p = 0.17). However, patients in the ACDF group had a higher reoperation rate than patients in the c-ADR group (4.6% vs 1.5%, p = 0.02).

CONCLUSIONS At the midterm follow-up after treatment of CSM, better functional outcomes as reflected by NDI and SF-36 scores were noted in the c-ADR group than those in the ACDF group. c-ADR had the advantage of retaining range of motion at the level of the intervertebral disc surgical site without causing more complications. A large sample size with long-term follow-up studies may be required to confirm these findings in the future.

Use of zero-profile device for contiguous three-level anterior cervical discectomy and fusion: comparison with cage and plate construct

J Neurosurg Spine 35:219–226, 2021

The aim of this study was to compare a traditional cervical cage with a zero-profile (ZP) fixation device in patients who underwent three-level anterior cervical decompression and fusion (ACDF) in terms of patient-reported outcomes (visual analog scale [VAS], Japanese Orthopaedic Association [JOA], and Neck Disability Index [NDI] scores), radiographic findings (sagittal alignment 2 years after surgery and likelihood of fusion), and complications.

METHODS This study was a retrospective case series. Between January 2012 and December 2016, 58 patients with cervical spondylotic myelopathy (CSM) who required three-level ACDF procedures, as identified by spinal surgeons, were treated with three-level ACDF and an anterior cage-plate construct (ACPC) (n = 38) or a three-level stand-alone ZP device (n = 20). On the basis of patient choice, patients were divided into two groups (ACPC group and ZP group). All patients completed a minimum of 2 years of follow-up. Patient-reported outcome scores included VAS, JOA, and NDI scores. The radiographic findings included sagittal alignment and likelihood of fusion 2 years after surgery. Data related to patient-reported outcomes and sagittal alignment were collected preoperatively, postoperatively, and at the final follow-up. Intraoperative and postoperative complications were also documented and analyzed.

RESULTS The clinical outcomes, including VAS, JOA, and NDI scores, showed improvement in both groups, and no significant difference was observed between the two groups. Sagittal alignment and height of the fused segments were restored in all patients. However, the authors found no differences between the ZP and ACPC groups, and the groups exhibited similar fusion rates. The authors found no differences in complications, including dysphagia, adjacent-segment degeneration, and postoperative hematoma, between the groups.

CONCLUSIONS Use of ZP implants yielded satisfactory long-term clinical and radiological outcomes that were similar to those of the standard ACPC. Additionally, the rates of complications between the groups were not significantly different. Although the best surgical option for multilevel CSM remains controversial, the results of this work suggest that ACDF with the ZP device is feasible, safe, and effective, even for multilevel CSM.

Nonunion Rates After Anterior Cervical Discectomy and Fusion: Comparison of Polyetheretherketone vs Structural Allograft Implants

Neurosurgery 89:94–101, 2021

Although advances in implant materials, such as polyetheretherketone (PEEK), have been developed aimed to improve outcome after anterior cervical discectomy and fusion (ACDF), it is essential to confirm whether these changes translate into clinically important sustained benefits.

OBJECTIVE: To compare the radiographic and clinical outcomes of patients undergoing up to 3-level ACDF with PEEK vs structural allograft implants.

METHODS: In this cohort study, radiographic and symptomatic nonunion rates were compared in consecutive patients who underwent 1 to 3 level ACDF with allograft or PEEK implant. Prospectively collected clinical data and patient-reported outcome (PRO) scores were compared between the allograft and PEEK groups. Regression analysis was performed to determine the predictors of nonunion.

RESULTS: In total, 194 of 404 patients met the inclusion criteria (79% allograft vs 21% PEEK). Preoperative demographic variables were comparable between the 2 groups except for age. The rate of radiographic nonunion was higher with PEEK implants (39% vs 27%, P = .0035). However, a higher proportion of nonunion in the allograft cohort required posterior instrumentation (14% vs 3%, P = .039). Patients with multilevel procedures and PEEK implants had up to 5.8 times the risk of radiographic nonunion, whereas younger patients, active smokers, and multilevel procedures were at higher risk of symptomatic nonunion.

CONCLUSION: Along with implant material, factors such as younger age, active smoking status, and the number of operated levels were independent predictors of fusion failure. Given the impact of nonunion on PRO, perioperative optimization of modifiable factors and surgical planning are essential to ensure a successful outcome.

A single-center retrospective analysis of 3- or 4-level anterior cervical discectomy and fusion

J Neurosurg Spine 34:45–51, 2021

Anterior cervical discectomy and fusion (ACDF) is a safe and effective intervention to treat cervical spine pathology. Although these were originally performed as single-level procedures, multilevel ACDF has been performed for patients with extensive degenerative disc disease. To date, there is a paucity of data regarding outcomes related to ACDFs of 3 or more levels. The purpose of this study was to compare surgical outcomes of 3- and 4-level ACDF procedures.

METHODS The authors performed a retrospective chart review of patients who underwent 3- and 4-level ACDF at the University of Virginia Health System between January 2010 and December 2017. In patients meeting the inclusion/exclusion criteria, demographics, fusion rates, time to fusion, and reoperation rates were evaluated. Fusion was determined by < 1 mm of change in interspinous distance between individual fused vertebrae on lateral flexion/extension radiographs and lack of radiolucency between the grafts and vertebral bodies. Any procedure requiring a surgical revision was considered a failure.

RESULTS Sixty-six patients (47 with 3-level and 19 with 4-level ACDFs) met the inclusion/exclusion criteria of having at least one lateral flexion/extension radiograph series ≥ 12 months after surgery. Seventy percent of 3-level patients and 68% of 4-level patients had ≥ 24 months of follow-up. Ninety-four percent of 3-level patients and 100% of 4-level patients achieved radiographic fusion for at least 1 surgical level. Eighty-eight percent and 82% of 3- and 4-level patients achieved fusion at C3–4; 85% and 89% of 3- and 4-level patients achieved fusion at C4–5; 68% and 89% of 3- and 4-level patients achieved fusion at C5–6; 44% and 42% of 3- and 4-level patients achieved fusion at C6–7; and no patients achieved fusion at C7–T1. Time to fusion was not significantly different between levels. Revision was required in 6.4% of patients with 3-level and in 16% of patients with 4-level ACDF. The mean time to revision was 46.2 and 45.4 months for 3- and 4-level ACDF, respectively. The most common reason for revision was worsening of initial symptoms.

CONCLUSIONS The authors’ experience with long-segment anterior cervical fusions shows their fusion rates exceeding most of the reported fusion rates for similar procedures in the literature, with rates similar to those reported for short-segment ACDFs. Three-level and 4-level ACDF procedures are viable options for cervical spine pathology, and the authors’ analysis demonstrates an equivalent rate of fusion and time to fusion between 3- and 4-level surgeries.

 

Pseudarthrosis in anterior cervical discectomy and fusion with a self-locking, stand-alone cage filled with hydroxyapatite

J Neurosurg Spine 33:717–726, 2020

The goal of this study was to evaluate the incidence of pseudarthrosis after the treatment of cervical degenerative disc disease (CDDD) with anterior cervical discectomy and fusion (ACDF) in which self-locking, stand-alone intervertebral cages filled with hydroxyapatite were used.

METHODS The authors performed a retrospective cohort study of 49 patients who underwent 1- to 3-level ACDF with self-locking, stand-alone intervertebral cages without plates, with a minimum 2 years of follow-up. The following data were extracted from radiological and clinical charts: age, sex, time and type of pre- and postoperative signs and symptoms, pain status (visual analog scale [VAS]), functional status (Neck Disability Index [NDI]), history of smoking, bone quality (bone densitometry), and complications. Pseudarthrosis was diagnosed by a blinded neuroradiologist using CT scans. Clinical improvement was assessed using pre- and postoperative comparison of VAS and NDI scores. The Wilcoxon test for paired tests was used to evaluate statistical significance using a p value of < 0.05.

RESULTS Three patients (6%) developed symptomatic pseudarthrosis requiring reoperation, with only 1 patient showing clinical worsening due to pseudarthrosis, while the other 2 with pseudarthrosis had associated disc disease at an adjacent level. The rate of symptomatic pseudarthrosis according to the number of operated levels was 0% for 1 level, 8.7% (2/23 patients) for 2 levels, and 7.7% (1/13 patients) for 3 levels. The total pseudarthrosis rate (including both symptomatic and asymptomatic patients) was 16.4%. Considering the clinical outcomes, there was a significant improvement of 75.6% in neck pain and 95.7% in arm pain, as well as a 64.9% improvement in NDI scores. Complications were observed in 18.4% of patients, with adjacent-level degenerative disease being the most prevalent at 14.3%.

CONCLUSIONS ACDF with self-locking, stand-alone cages filled with a hydroxyapatite graft can be used for the surgical treatment of 1- to 3-level CDDD with clinical and radiological outcomes significantly improved after a minimum 2-year follow-up period. Comparative studies are necessary.

 

Lower Hounsfield units on CT are associated with cage subsidence after anterior cervical discectomy and fusion

J Neurosurg Spine 33:425–432, 2020

A consequence of anterior cervical discectomy and fusion (ACDF) is graft subsidence, potentially leading to kyphosis, nonunion, foraminal stenosis, and recurrent pain. Bone density, as measured in Hounsfield units (HUs) on CT, may be associated with subsidence. The authors evaluated the association between HUs and subsidence rates after ACDF.

METHODS A retrospective study of patients treated with single-level ACDF at the University of California, San Francisco, from 2008 to 2017 was performed. HU values were measured according to previously published methods. Only patients with preoperative CT, minimum 1-year follow-up, and single-level ACDF were included. Patients with posterior surgery, tumor, infection, trauma, deformity, or osteoporosis treatment were excluded. Changes in segmental height were measured at 1-year follow-up compared with immediate postoperative radiographs. Subsidence was defined as segmental height loss of more than 2 mm.

RESULTS A total of 91 patients met inclusion criteria. There was no significant difference in age or sex between the subsidence and nonsubsidence groups. Mean HU values in the subsidence group (320.8 ± 23.9, n = 8) were significantly lower than those of the nonsubsidence group (389.1 ± 53.7, n = 83, p < 0.01, t-test). There was a negative correlation between the HU values and segmental height loss (Pearson’s coefficient −0.735, p = 0.01). Using receiver operating characteristic curves, the area under the curve was 0.89, and the most appropriate threshold of HU value was 343.7 (sensitivity 77.1%, specificity 87.5%). A preoperative lower HU is a risk factor for postoperative subsidence (binary logistic regression, p < 0.05). The subsidence rate and distance between allograft and polyetheretherketone (PEEK) materials were not significantly different (PEEK 0.9 ± 0.7 mm, allograft 1.0 ± 0.7 mm; p > 0.05).

CONCLUSIONS Lower preoperative CT HU values are associated with cage subsidence in single-level ACDF. Preoperative measurement of HUs may be useful in predicting outcomes after ACDF.

The safety and efficacy of anterior versus posterior decompression surgery in degenerative cervical myelopathy: a prospective randomized trial

J Neurosurg Spine 33:288–296, 2020

The safety and efficacy of anterior and posterior decompression surgery in degenerative cervical myelopathy (DCM) have not been validated in any prospective randomized trial.

METHODS In this first prospective randomized trial, the patients who had symptoms or signs of DCM were randomly assigned to undergo either anterior cervical discectomy and fusion or posterior laminectomy with or without fusion. The primary outcome measures were the change in the visual analog scale (VAS) score, Neck Disability Index (NDI), and Nurick myelopathy grade 1 year after surgery. The secondary outcome measures were intraoperative and postoperative complications, hospital stay, and Odom’s criteria. The follow-up period was at least 1 year.

RESULTS A total of 68 patients (mean age 53 ± 8.3 years, 72.3% men) underwent prospective randomization. There was a significantly better outcome in the NDI and VAS scores in the anterior group at 1 year (p < 0.05). Nurick myelopathy grading showed nonsignificant improvement using the posterior approach group (p = 0.79). The mean operative duration was significantly longer in the anterior group (p < 0.001). No significant difference in postoperative complications was found, except postoperative dysphagia was significantly higher in the anterior group (p < 0.05). There was no significant difference in postoperative patient satisfaction (Odom’s criteria) (p = 0.52). The mean hospital stay was significantly longer in the posterior group (p < 0.001).

CONCLUSIONS Among patients with multilevel DCM, the anterior approach was significantly better regarding postoperative pain, NDI, and hospital stay, while the posterior approach was significantly better in terms of postoperative dysphagia and operative duration.

Asymptomatic ACDF Nonunions Underestimate the True Prevalence of Radiographic Pseudarthrosis

Spine 2020;45:E776–E780

Study Design. Secondary analysis of subjects in the control anterior cervical discectomy and fusion (ACDF) arm of Medtronic Investigational Device Exemption (IDE) trials for cervical disc arthroplasty (CDA).

Objectives. To compare patient-reported outcomes (PROs) in patients with radiographic nonunion to patients with a solid fusion. Summary of

Background Data. The true prevalence of nonunion after ACDF is unknown. Nonunion may be underreported, as some patients are not symptomatic enough to justify radiographic evaluation. Methods. Three hundred forty-five subjects enrolled in the control arm of IDE trials for CDA who had single-level ACDF with allograft and plate with 24 month data formed the study cohort. Using the 24-month postop evaluation, subjects were divided into those who had radiographic fusion and those who did not using strict study criteria. SF-36, NDI, Neck and Arm pain NRS scores were reported at 12, 24, 36, 60, and 84 months postop. For subjects who had secondary surgery failures, the last observations before the secondary surgery were carried forward to future visits for the analysis.

Results. Forty-four (13%) patients had radiographic nonunion and 301 (87%) were fused at 24 months postop. At 24 months, PROs were similar between the two groups. Seven patients in the Nonunion group (16%) and 10 (3%) in the Fused group had additional surgery at the index level prior to the 24 follow-up (P¼0.003). Over the 84-month follow-up a total of 9 patients in the Nonunion group (21%) and 22 (7%) in the Fused group had additional surgery at the index level (P¼0.009).

Conclusion. While the radiographic nonunion rate at 24 months was 13%, PROs show that many of the radiographic nonunions were asymptomatic. Although the majority of patients with radiographic nonunion did not undergo additional surgery, the rate of secondary surgeries at the index level was significantly higher in the radiographic nonunion group.

Level of Evidence: 2

Anterior Cervical Discectomy and Fusion in the Outpatient Ambulatory Surgery Setting: Analysis of 2000 Consecutive Cases

Neurosurgery 2019 DOI:10.1093/neuros/nyz514

In an effort to improve efficiency of care, ambulatory surgery centers (ASCs) have emerged as lower-cost options. Anterior cervical discectomy and fusion (ACDF) is one of the most prevalent spine surgeries performed and rarely requires overnight stays in the hospital, supporting its migration to the ASC. Recent analyses have called into question the safety of outpatient ACDF, potentially slowing its adoption. ASC-ACDF studies have largely been limited to small series, precluding an accurate assessment of safety.

OBJECTIVE: To analyze 2000 ASC-ACDF cases, describe patient selection and perioperative protocol, and report associated safety profile.

METHODS: A total of 2000 patients who underwent 1 to 3 level ACDF in a single ASC from 2006 to 2018 were included in this retrospective analysis. Patients were observed in a 4-h postanesthesia care unit (PACU) with a multimodal pain management regiment. Data were collected on patient demographics, comorbidities, operative details, and 30- and 90-d morbidity.

RESULTS: Of the 2000 patients, 10 (0.5%) required transfer to an inpatient setting within the 4-h observation. Reasons for transfer included hematoma (2), pain control (2), cerebrospinal fluid leak (1), and medical complications (5). Six patients (0.3%) underwent reoperation within 30 d. All-cause 30-d readmission was 1.9%.

CONCLUSION: An analysis of 2000 ACDF patients in an ASC setting with a standardized perioperative protocol demonstrates that surgical complications occur at a low rate (<1%) and can be appropriately diagnosed and managed in a 4-h PACU. In an effort to decrease healthcare costs, surgeons can safely perform ACDFs in an ASC utilizing patient selection criteria and perioperative management protocols similar to those reported here.