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

P121. Chronic opioid use following anterior cervical discectomy and fusion surgery for degenerative cervical pathology

Introduction Subsequent herniated cervical disc (HCD) and revision anterior cervical discectomy and fusion (ACDF) is not an uncommon disease and procedure. And we, as a spinal surgeon, have some difficulties in decision-making, because of the airway, esophagus, and vocal cord problems. Adjacent segment disease is well known as the pathologic process, in which the changes in the other segment may occur at the cranial or caudal segment. In this study, we discuss about the subsequent HCD which requires surgical treatment following single-level ACDF. Materials and Methods From 2006 to 2012, 27 Korean patients, who were operated for subsequent HCD following previous ACDF, were enrolled. The subsequent HCD was detected not only in adjacent segments just around fused spine but also in the skipped segments. A total of 23 patients were approached anteriorly (22 revision ACDF and 1 anterior foraminotomy) and 4 patients were approached posteriorly for posterior keyhole surgery. All 23 patients with anterior approach were evaluated for vocal cord palsy before anterior revision surgery. We retrospectively reviewed and analyzed the pre- and postoperative data. Results The subsequent HCD significantly occurred on the caudal segment in patients with C3–4 and C4–5 fused patients and on the cranial segment in C6–7 and C7–T1 fused patients ( p = 0.045). In C5–6 fused patients, the subsequent HCD occurred similarly, both caudally and cranially (5 cranially, 6 caudally). The use of plate in primary ACDF has no significant effect on either the caudal or the cranial segment ( p = 0.168). The direction of approach in primary ACDF (right vs. left) was mainly on contralateral side to the patient's symptom ( p = 0.007), whereas there was no laterality of approach in the revision ACDF according to the symptom and previous ACDF ( p = 0.767). Vocal cord palsy developed only in one patient with anterior keyhole surgery, who had been approached right in primary ACDF and left in revision surgery and there was right-sided vocal cord damage. Conclusion Revision ACDF was the major surgical method for subsequent HCD. There was no relationship between the laterality of the approach according to the previous operation and development of vocal cord palsy. The vocal cord palsy was detected in a significantly lower incidence (4.3%, 1/23) compared with the results of other studies. The subsequent HCD had a tendency of developing in the caudal segments in C3–4, 4–5 fused patients and in cranial segment in C6–7, C7–T1 fused patients. In C5–6 fused patients, the subsequent HCD occurred both caudally and cranially.

Retrospective cohort study. To compare short-term morbidity for primary and revision anterior cervical discectomy and fusion (ACDF). Revision ACDF procedures are relatively common, yet their risks are poorly characterized in the literature. There is a need to assess the relative risk of revision ACDF procedures compared with primary surgery. The prospectively collected American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent primary and revision ACDF from 2005 to 2014. The occurrence of 30-day postoperative complications, readmission, operative time, and postoperative length of stay were compared between primary and revision procedures using multivariate regression to control for patient and operative characteristics. A total of 20,383 ACDF procedures were identified, 1219 (6.0%) of which were revision cases. On multivariate analysis, revision procedures were associated with significantly increased risk of any adverse event (relative risk [RR] 2.3, P < 0.001), any severe adverse event (RR 2.2, P < 0.001), thromboembolic events (RR 3.3, P = 0.001), surgical site infections (RR 3.2, P < 0.001), return to the operating room (RR 1.9, P = 0.001), any minor adverse event (RR 2.5, P < 0.001), and blood transfusion (RR 8.3, P < 0.001). Revision procedures had significantly increased risk of readmission within 30 days (RR = 1.6, P = 0.001). Minor, but statistically significant increases in average operative time and postoperative length of stay were identified for revisions procedures (7 min and half a day, respectively [P < 0.001 for both]). Revision procedures were associated with significantly increased risk of multiple adverse outcomes, including thromboembolic events, surgical site infections, return to the operating room, blood transfusion, and readmission within 30 days. These results are important for patient counseling and risk stratification. 3.

Preoperative laryngoscopic examination in patients undergoing repeat anterior cervical discectomy and fusion

This study was a retrospective review. The purpose of this study was to investigate the correlation analysis between Hounsfield units (HU) and dual x-ray absorptiometry (DXA) based on the clinical results of patients who underwent anterior cervical discectomy and fusion (ACDF) surgery. There is no technique to directly measure bone mineral density (BMD) in the cervical spine. As computed tomography is a very popular preoperative planning modality, using the HU value from that analysis to predict osteoporosis is important for patient outcomes and applications in the clinical field. We reviewed the records for 235 patients who underwent 1-level (n=120) or 2-level (n=115) ACDF surgery. In the 1-level ACDF group, the HU was measured from C3 to C6 vertebra, while that for the 2-level ACDF group was measured from 3 surgical index vertebrae. The correlation patterns were analyzed with the corresponding DXA (T-score) for each patient. Subsidence of fusion segment was defined as change in distance between plate-tip and upper (lower) margin of the vertebra (index level) after 4 months of follow-up. In addition, to determine the relevant factors that influence fusion segment subsidence, other preoperative (C2 slope, C7 slope, C2-C7 angle, and C2-C7 sagittal vertical axis) and postoperative parameters (coronal angle and segmental angle change) were measured. The correlation coefficient between HU and DXA ranged from 0.57 to 0.71 in the 1-level ACDF group and from 0.59 to 0.66 in the 2-level ACDF group. The correlation between HU and DXA was statistically significant regardless of the degree of anterior osteophyte (r=-0.65 to 0.78). Total subsidence height was 3.8 mm after ACDF, and both HU and DXA were statistically correlated with total subsidence (r=0.26-0.28). In multivariate analysis, HU (middle vertebra) value was statistically associated with the degree of total subsidence. The high-subsidence group (≥4.5 mm) showed smaller HU values (284.1 vs. 316.0) and T-scores (-0.5 vs. 0.1) compared to the low-subsidence group (<4.5 mm). The discrepancy group, defined as cases with excess plate shift on 1 side, also showed smaller HU values (260.4 vs. 312.4) and higher degrees of total subsidence than the matched group. The correlation between HU in cervical computed tomography and lumbar DXA (T-score) was statistically significant in both 1-level and 2-level ACDF. The level of BMD (HU or DXA) is a very important factor for clinically determining the amount and regularity of subsidence after ACDF. Therefore, HU can be a good alternative assessment to accurately reflect as much of the BMD degree as DXA in the cervical spine.

Anterior cervical discectomy and fusion (ACDF) is one of the most frequently performed cervical surgeries in the world, yet there have been several reported complications. To determine the actual incidence of complications related to ACDF as well as any risk variables that may have been identified in earlier research. To evaluate the origin, presentation, natural history, and management of the risks and the complications, we conducted a thorough assessment of the pertinent literature. An evaluation of clinical trials and case studies of patients who experienced one or more complications following ACDF surgery was done using a PubMed, Cochrane Library, and Google Scholar search. Studies involving adult human subjects that were written in the English language and published between 2012 and 2022 were included in the search. The search yielded 79 studies meeting our criteria. The overall rates of complications were as follows: Dysphagia 7.9%, psudarthrosis 5.8%, adjacent segment disease (ASD) 8.8%, esophageal perforations (EPs) 0.5%, graft or hardware failure 2.2%, infection 0.3%, recurrent laryngeal nerve palsy 1.7%, cerebrospinal fluid leak 0.8%, Horner syndrome 0.5%, hematoma 0.8%, and C5 palsy 1.9%. Results showed that dysphagia was a common postoperative sequelae with bone morphogenetic protein use and a higher number of surgical levels being the major risk factors. Pseudarthrosis rates varied depending on the factors such as asymptomatic radiographic graft sinking, neck pain, or radiculopathy necessitating revision surgery. The incidence of ASD indicated no data to support anterior cervical plating as more effective than standalone ACDF. EP was rare but frequently fatal, with no correlation found between patient age, sex, body mass index, operation time, or number of levels.

ObjectivesThis study aims to compare the outcomes between two anterior decompression and fusion techniques to treat multilevel cervical spondylotic myelopathy (MCSM).MethodsAfter the screening for eligibility, a total of 66 patients were admitted to this study. These participants underwent anterior surgeries due to MCSM in our hospital between June 2016 and July 2018. All participants underwent either the anterior cervical discectomy and fusion (ACDF) surgery (ACDF group) or the combination of ACDF and anterior cervical corpectomy and fusion (ACCF), which was the anterior cervical hybrid decompression and fusion (ACHDF) surgery group. All the patients were followed up ≥18 months, the average latest followed up time was 23.64 (±2.69) months. The length of hospitalization, operation time, blood loss, visual analog scale (VAS), Japanese Orthopaedic Association (JOA) score, improvement rate, Hounsfield units (HU) of C3–C7, cobb angle, and anterior column height of fusion levels pre and post operation were analyzed.ResultsThere were no statistical differences between the ACDF and ACHDF groups regarding the length of hospitalization, operation time, blood loss, HU of C3–C7, VAS, JOA score, improvement rate, cobb angle, and anterior column height in fusion levels in pre-operation and 3 months after operation (all P > 0.05). However, compared with the ACHDF group, the ACDF group achieved significantly better improvement in the anterior column height of fusion levels in the final 18–29 months post-operatively (P < 0.05).ConclusionsBoth approaches of ACDF alone and a combination of ACDF and ACCF can achieve satisfactory outcomes in the treatment of MCSM, but ACDF has better outcomes in maintaining anterior column height of fusion levels.

Thursday, September 27, 2018 3:35 PM–5:05 PM Section on Motion Technology Abstract Presentations: 132. Subsequent cervical spine surgery after cervical disc arthroplasty and anterior cervical discectomy and fusion

Anterior cervical fusion: a comparison of cage, dowel and dowel-plate constructs

Does two-level hybrid surgery promote early fusion compared with two-level anterior cervical discectomy and fusion?

Retrospective cost-utility analysis. To conduct a cost-analysis comparing SC versus Allo over a five-year time horizon. Synthetic cage (SC) and allograft (Allo) are two commonly used interbody choices for anterior cervical discectomy and fusion (ACDF) surgery. Previous analyses comparative analyses have reached mixed conclusions regarding their cost-effectiveness, yet recent estimates provide high-quality evidence. A decision-analysis model comparing the use of Allo versus SC was developed for a hypothetical 60-year-old patient with cervical spondylotic myelopathy (CSM) undergoing single level ACDF surgery. A comprehensive literature review was performed to estimate probabilities, costs (2020 USD) and Quality-Adjusted Life Years (QALYs) gained over a 5-year period. A probabilistic sensitivity analysis using a Monte Carlo Simulation of 1000 patients was carried out to calculate incremental cost effectiveness ratio (ICER) and net monetary benefits (INMB). One-way deterministic sensitivity analysis was performed to estimate the contribution of individual parameters to uncertainty in the model. The use of Allo was favored in 81.6% of the iterations at a societal willing-to-pay threshold (WTP) of 50,000 USD/QALY. Allo dominated (higher net QALYs and lower net costs) in 67.8% of the iterations. The INMB in the Allo group was 2,650 USD at a WTP threshold of 50,000 USD/QALY. One-way deterministic sensitivity analysis revealed that the cost of the index surgery was the only factor which significantly contributed to uncertainty. Cost-utility analysis suggests that Allograft maybe a more cost-effective option compared to synthetic cages in adult patients undergoing ACDF for CSM.

To conduct a meta-analysis to assess dysphagia complicating single-level and multiple-level (≥2) anterior cervical discectomy and fusion (ACDF) surgery. Electronic searches were performed using four electronic databases from their inception to December 2017. Relevant studies reporting the rate of dysphagia as an endpoint for patients undergoing ACDF for degenerative disease, myelopathy, cervical canal stenosis or ossification of the posterior longitudinal ligament were identified according to prior inclusion and exclusion criteria. Statistical analysis was performed using a fixed effect model. P-scores were used to rank the levels of ACDF based on the rate of dysphagia. I2 was used to explore heterogeneity. Ten studies were identified and included in the systematic review and meta-analysis, with a total of 4,018 patients identified; 2,362 patients underwent single-level ACDF, while 1,656 underwent multiple level (≥2 ACDF). The mean age ranged from 49.45 to 57.77 years. Mean follow-up time ranged from 2 days to 27.3 months. Overall, meta-analysis demonstrated a statistically significant higher dysphagia rate for multiple-level ACDF (6.6%) than for single-level ACDF (4%) (P heterogeneity =0.151, OR =1.42, 95% CI: 1.05-1.91, I2=32%). Dysphagia is a relatively common complication in the early postoperative period following ACDF and may cause patients significant discomfort and distress. This meta-analysis demonstrates a higher rate of dysphagia with multiple-level ACDF than with single-level ACDF at a period of 12-24 months.

Anterior cervical discectomy and fusion is a standard treatment for symptomatic cervical disc disease, but pseudarthrosis and accelerated adjacent-level disc degeneration may develop. Cervical disc arthroplasty was developed to preserve the kinematics of the functional spinal unit. Trials comparing arthroplasty with anterior cervical discectomy and fusion have shown unclear benefits in terms of clinical results, neck motion at the operated level, adverse events, and the need for secondary surgical procedures. Only randomized clinical trials were included in this meta-analysis, and the search strategy followed the requirements of the Cochrane Library Handbook. Two reviewers independently assessed the methodological quality of each included study and extracted the relevant data. Twenty-seven randomized clinical trials were included; twelve studies were Level I and fifteen were Level II. The results of the meta-analysis indicated longer operative times, more blood loss, lower neck and arm pain scores reported on a visual analog scale, better neurological success, greater motion at the operated level, fewer secondary surgical procedures, and fewer such procedures that involved supplemental fixation or revision in the arthroplasty group compared with the anterior cervical discectomy and fusion group. These differences were significant (p < 0.05). The two groups had similar lengths of hospital stay, Neck Disability Index scores, and rates of adverse events, removals, and reoperations (p > 0.05). The meta-analysis revealed that anterior cervical discectomy and fusion was associated with shorter operative times and less blood loss compared with arthroplasty. Other outcomes after arthroplasty (length of hospital stay, clinical indices, range of motion at the operated level, adverse events, and secondary surgical procedures) were superior or equivalent to the outcomes after anterior cervical discectomy and fusion.

25. Perioperative complications associated with epidural injections followed by cervical decompression and fusion

Systematic Review of the Literature. The purpose of this study was to perform a systematic review describing fusion rates for anterior cervical discectomy and fusion (ACDF) using autograft vs various interbody devices augmented with different osteobiologic materials. A systematic review limited to the English language was performed in Medline, Embase and Cochrane library using Medical Subject Heading (MeSH) terms. Studies that evaluated fusion after ACDF using autografts and osteobiologics combined with PEEK, carbon fibre, or metal cages were searched for. Articles in full text that met the criteria were included in the review. The main outcomes evaluated were the time taken to merge, the definition of the fusion assessment, and the modality of the fusion assessment. The risk of bias of each article was assessed by the MINORS score or ROB 2.0 depending on the randomisation process. The total number of references reviewed was six hundred and eighty-two. After applying the inclusion criteria, 54 were selected for the retrieval of the full text. Eight studies were selected and included for final analysis in this study. Fusion rates were reported between 83.3% and 100% for autograft groups compared to 46.5% and 100% for various interbody device/osteobiological combinations. The overall quality of the evidence in all radiographic fusion studies was considered insufficient due to a serious risk of bias. Mechanical interbody devices augmented with osteobiologics performed similarly to autografts in terms of reliability and efficacy. Their time to fusion and fusion rate were comparable to autografts at the end of the final follow-up.