Kaye, I. David

Study Design: Retrospective cohort study. Objective: The purposes of this study were to determine the rate of improvement of significant preoperative weakness, identify risk factors for failure to improve, and characterize the motor recovery of individual motor groups. Summary of Background Data: While neck and arm pain reliably improve following anterior cervical discectomy and fusion (ACDF), the frequency and magnitude of motor recovery following ACDF remain unclear. Methods: We performed a retrospective review of patients undergoing 1–4-level ACDF at a single institution between September 2015 and June 2016. Patients were subdivided into 2 groups based upon the presence or absence of significant preoperative weakness, which was defined as a motor grade <4 in any single upper extremity muscle group. Clinical notes were reviewed to determine affected muscle groups, rates of motor recovery, and risk factors for failure to improve. Results: We identified 618 patients for inclusion. Significant preoperative upper extremity weakness was present in 27 patients (4.4%). Postoperatively, 19 of the affected patients (70.3%) experienced complete strength recovery, and 5 patients (18.5%) experienced an improvement in muscle strength to a motor grade ≥4. The rate of motor recovery postoperatively was 85.7% in the triceps, 83.3% in the finger flexors, 83.3% in the hand intrinsics, 50.0% in the biceps, and 25.0% in the deltoids. Risk factors for failure to experience significant motor improvement were the presence of myelomalacia (odds ratio: 28.9, P<0.01) and the performance of >2 levels of ACDF (odds ratio: 10.1, P<0.01). Conclusions: Patients with substantial preoperative upper extremity weakness can expect high rates of motor recovery following ACDF, though patients with deltoid weakness, myelomalacia, and >2 levels of ACDF are less likely to experience significant motor improvement.

Study Design: This was a multicenter retrospective cohort study. Objective: The purpose of this study was to compare the surgical and radiographic outcomes of patients undergoing posterior cervical fusion (PCF) with constructs extending from C2 to T2 to patients with constructs extending from C3 to T1. Summary of Background Data: Limited evidence exists regarding the appropriate level of proximal and distal extension of PCF constructs. Methods: A multicenter retrospective cohort study of patients who underwent PCF between 2012 and 2020 was performed. Surgical and radiographic outcomes were compared between those who had C3–T1 or C2–T2 constructs. Results: A total of 155 patients were included in the study (C2–T2: 106 patients, C3–T1: 49 patients). There were no significant differences in demographics or preoperative symptoms between cohorts. Fusion rates were significantly higher in the C2–T2 (93%) than the C3–T1 (80%, P=0.040) cohort. When comparing the C2–T2 to the C3–T1 cohort, the C3–T1 cohort had a significantly greater rate of proximal junctional failure (2% vs. 10%, P=0.006), distal junctional failure (1% vs. 20%, P<0.001) and distal screw loosening (4% vs. 15%, P=0.02). Although ∆C2–C7 sagittal vertical axis increased significantly in both cohorts (C2–T2: 6.2 mm, P=0.04; C3–T1: 8.4 mm, P<0.001), correction did not significantly differ between groups (P=0.32). The C3–T1 cohort had a significantly greater increase in ∆C2 slope (8.0 vs. 3.1 degrees, P=0.03) and ∆C0–C2 Cobb angle (6.4 vs. 1.2 degrees, P=0.04). Conclusion: In patients undergoing PCF, a C2–T2 construct demonstrated lower rates of pseudarthrosis, distal junctional failure, proximal junctional failure, and compensatory upper cervical hyperextension compared with a C3–T1 construct.

Study Design This study is a retrospective case control. Objectives This study aims to determine whether cervical degenerative spondylolisthesis (DS) is associated with increased baseline neck/arm pain and inferior health quality states compared to a similar population without DS. Methods Patient demographics, pre-operative radiographs, and baseline PROMs were reviewed for 315 patients undergoing anterior cervical decompression and fusion (ACDF) with at least 1 year of follow-up. Patients were categorized based on the presence (S) or absence of a spondylolisthesis (NS). Statistically significant variables were further explored using multiple linear regression analysis. Results 49/242 (20%) patients were diagnosed with DS, most commonly at the C4–5 level (27/49). The S group was significantly older than the NS group (58.0 ± 10.7 vs 51.9 ± 9.81, P = .001), but otherwise, no demographic differences were identified. Although a higher degree of C2 slope was found among the S cohort (22.5 ± 8.63 vs 19.8 ± 7.78, P = .044), no differences were identified in terms of preoperative visual analogue scale (VAS) neck pain or NDI. In the univariate analysis, the NS group had significantly increased VAS arm pain relative to the S group (4.93 ± 3.16 vs 3.86 ± 3.30, P = .045), which was no longer significant in the multivariate analysis. Conclusions Although previous reports have suggested an association between cervical DS and neck pain, we could not associate the presence of DS with increased baseline neck or arm pain. Instead, DS appears to be a relatively frequent (20% in this series) age-related condition reflecting radiographic, rather than necessarily clinical, disease.

Background: The surgical management of adult spinal deformity (ASD) is a major surgical undertaking associated with considerable perioperative risk and a substantial complication profile. Although the natural history and risk factors associated with proximal junctional kyphosis (PJK) and proximal junctional failure are widely reported, distal junctional failure (DJF) is less well understood. Study Design: A systematic review was carried out. Objectives: The primary objective is to identify the risk factors associated with DJF. The secondary objective is to delineate the incidence rate and causative factors associated with DJF. Methods: A systematic review of articles in Medline/PubMed and The Cochrane Library databases was performed according to preferred reporting items for systematic reviews and meta-analyses guidelines. Data was collated to determine the prevalence of DJF and overall revision rates, and identify potential risk factors for development of DJF. Results: Twelve studies were included for systematic review. There were 81/2261 (3.6%) cases of DJF. Overall, DJF represented 27.3% of all revision surgeries. Anterior-posterior surgery had a reduced incidence of postoperative DJF [5.0% vs. 8.7%; P=0.08; relative risk (RR)=1.73], as did patients below 60 years of age at the time of surgery (2.9% vs. 3.9%; P=0.09; RR=1.34). There was a higher incidence of DJF among those patients who received interbody fusion (9.9% vs. 5.1%; P=0.06; RR=1.93) compared with those who did not. However, none of these findings reached statistical significance. There were significantly more rates of DJF for fusions ending on L5 compared with constructs fused to the sacrum (11.7% vs. 3.6%; P=0.02; RR=3.28). Conclusions: Cohorts 60 years and above of age at the time of surgery and patients managed with posterior-only fusion or interbody fusion have increased incidences of DJF. Fusion to L5 instead of the sacrum significantly influences DJF rates. However, the quality of available evidence is low and further high-quality studies are required to more robustly analyze the clinical, radiographic, and surgical risk factors associated with the development of DJF after ASD surgery.

Study Design: Retrospective cohort study. Objective: Studies investigating the impact of interbody subsidence in ACDF suggest a correlation between subsidence and worse radiographic and patient-reported outcomes. The purpose of this study was to assess whether allograft subsidence assessed on CT is associated with worse cervical alignment. Methods: We performed a retrospective review of a prospective cohort of patients undergoing 1 to 3 level ACDF. Cervical alignment was assessed on standing radiographs performed preoperatively, less than 2 months postoperatively, and greater than 6 months postoperatively. Allograft subsidence was assessed on CT scan performed at least 6 months postoperatively. Patients with at least 1 level demonstrating greater than 4mm of cage subsidence were classified as severe subsidence. Student’s t-test was used to compare all means between groups. Results: We identified 66 patients for inclusion, including 56 patients with non-severe subsidence and 10 patients with severe subsidence. For the entire cohort, there was a significant increase in C2-7 Lordosis (p = 0.005) and Segmental Lordosis (p < 0.00 001) from preoperative to early postoperative. On comparison of severely and non-severely subsided levels, severely subsided levels demonstrated a significantly greater loss of segmental lordosis from early to mid-term follow-up than non-severely subsided levels (-4.89 versus -2.59 degrees, p < 0.0001), manifesting as a significantly lower segmental lordosis at >6 months postoperative (0.54 versus 3.82 degrees, p < 0.00 001). There were no significant differences in global cervical alignment parameters between patients with severe and non-severe subsidence. Conclusions: Severe subsidence is associated with a significant increase in loss of segmental lordosis, but has minimal effect on global cervical alignment parameters.

Study Design: Retrospective database review. Objectives: The incidence and risk factors for surgical delay of multilevel spine fusion for adult spinal deformity (ASD), and the complications corresponding therewith, remain unknown. The objectives of this study are to assess the incidence and risk factors for unexpected delay of elective multilevel spinal fusions on the date of surgery as well as the postoperative complications associated with these delays. Methods: We conducted a retrospective review of the ACS-NSQIP database on patients undergoing elective spinal instrumentation of greater than 7 levels for ASD between the years 2005 and 2015. Preoperative risk factors for delay and postoperative complications were compared between the cohorts of patients with and without surgical delays. Results: Multivariate analysis of 1570 (15.6%) patients identified advanced age, male sex, American Society of Anesthesiologists (ASA) Class 4, and history of smoking as independent risk factors for delay. Patients experiencing surgical delay demonstrated longer operative times, increased intraoperative bleeding, longer hospitalizations, and significantly higher rates of postoperative complications. Patients experiencing delay demonstrated an almost 7-fold increase in mortality rate (3.4% vs 0.5%, P < .001). Conclusions: Delays in elective surgical care for spinal deformity are negatively related to patient outcomes. Advanced age, male sex, increased ASA class, and a history of smoking cigarettes place patients at risk for surgical delay of multilevel spinal fusion. Patients experiencing surgical delay are at higher risk for postoperative complications, including a 7-fold increase in mortality. These findings suggest that ASD surgery should be postponed in patients experiencing a delay, until modifiable risk factors can be medically optimized, and perhaps postponed indefinitely in those with nonmodifiable risk factors.

The management of thoracolumbar burst fractures is controversial with no universally accepted treatment algorithm. Several classification and scoring systems have been developed to assist in surgical decision-making. The most widely accepted are the Thoracolumbar Injury Classification and Severity Score (TLICS) and AOSpine Thoracolumbar Injury Classification Score (TL AOSIS) with both systems designed to provide a simple objective scoring criteria to guide the surgical or nonsurgical management of complex injury patterns. When used in the evaluation and treatment of thoracolumbar burst fractures, both of these systems result in safe and consistent patient care. However, there are important differences between the 2 systems, specifically in the evaluation of the complete burst fractures (AOSIS A4) and patients with transient neurological deficits (AOSIS N1). In these circumstances, the AOSpine system may more accurately capture and characterize injury severity, providing the most refined guidance for optimal treatment. With respect to surgical approach, these systems provide a framework for decision-making based on patient neurology and the status of the posterior tension band. Here we propose an operative treatment algorithm based on these fracture characteristics as well as the level of injury.

Study Design: Retrospective, single institution, multisurgeon case control series. Objective: To determine whether there are differences in reoperation rates or outcomes for patients undergoing 2-level posterolateral fusion (PLF) augmented by a transforaminal lumbar interbody fusion (TLIF) at only one of the levels or at both. Methods: A total of 416 patients were identified who underwent 2-level PLF with a TLIF at either one of those levels (n = 183) or at both (n = 233) with greater than 1-year follow-up. Demographic, surgical, radiographic, and clinical data was reviewed for each patient. These included age, sex, race, body mass index, smoking status, Charleston Comorbidity Index, operative time, estimated blood loss, length of stay, and patient-reported outcome measures. Results: Each cohort underwent 24 reoperations. Although the number of overall reoperations was not significantly different ( P > .05), among the reoperation types, there were significantly more reoperations for adjacent segment disease in the 2-level group compared to the 1-level group (19 vs 12, P = .04). There was no difference in reoperation for pseudarthrosis between the groups ( P > .05). Although both groups experienced significant improvements in Oswestry Disability Index ( P < .001) and Short Form–12 health questionnaire ( P < .001), there were no differences between improvements for 1- versus 2-level cohorts. Conclusions: For patients undergoing 2-level PLF in the setting of a TLIF, using a TLIF at one versus both levels does not seem to influence reoperation rates or outcomes. However, reoperation rates for adjacent segment disease are increased in the setting of a 2-level PLF augmented by a 2-level TLIF.