The effect of C2 screw type on perioperative outcomes and long-term stability after C2-T2 posterior cervical decompression and fusion.

PURPOSE: To determine if C2 pedicle versus pars screw type predicts change in fusion status, C2 screw loosening, cervical alignment, and patient-reported outcomes measures (PROMs) after C2-T2 posterior cervical decompression and fusion (PDCF). METHODS: All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy between 2013-2020 were retrospectively identified. Patients were dichotomized by C2 screw type into bilateral C2 pedicle and bilateral C2 pars screw groups. Preoperative and short- and long-term postoperative radiographic outcomes and PROMs were collected. Univariate and multivariate analysis compared patient factors, fusion status, radiographic measures, and PROMs across groups. RESULTS: A total of 159 patients met the inclusion/exclusion criteria (76 bilateral pedicle screws, 83 bilateral pars screws). Patients in the C2 pars relative to C2 pedicle screw group were on average more likely to have bone morphogenic protein (p = 0.001) and four-millimeter diameter rods utilized intraoperatively (p = 0.033). There were no significant differences in total construct and C2-3 fusion rate, C2 screw loosening, or complication and revision rates between C2 screw groups in univariate and regression analysis. Changes in C2 tilt, C2-3 segmental lordosis, C0-2 Cobb angle, proximal junctional kyphosis, atlanto-dens interval, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 screw type. CONCLUSION: There were no significant differences in fusion status, hardware complications, and radiographic and clinical outcomes based on C2 screw type following C2-T2 PCDF. Accordingly, intraoperative usage criteria can be flexible based on patient vertebral artery positioning and surgeon comfort level.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications. BACKGROUND: In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF. PATIENTS AND METHODS: All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups. RESULTS: A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups. CONCLUSIONS: Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF. LEVEL OF EVIDENCE: Level III.

A Longitudinal Evaluation of Coronavirus Disease 2019 and Its Effects on Spinal Decompressions With or Without Fusion.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The objectives were to (1) compare the safety of spine surgery before and after the emergence of coronavirus disease 2019 (COVID-19) and (2) determine whether patients with a history of COVID-19 were at increased risk of adverse events. SUMMARY AND BACKGROUND DATA: The COVID-19 pandemic had a tremendous impact on several health care services. In spine surgery, elective cases were canceled and patients received delayed care due to the uncertainty of disease transmission and surgical outcomes. As new coronavirus variants arise, health care systems require guidance on how to provide optimal patient care to all those in need of our services. PATIENTS AND METHODS: A retrospective review of patients undergoing spine surgery between January 1, 2019 and June 30, 2021 was performed. Patients were split into pre-COVID or post-COVID cohorts based on local government guidelines. Inpatient complications, 90-day readmission, and 90-day mortality were compared between groups. Secondary analysis included multiple logistic regression to determine independent predictors of each outcome. RESULTS: A total of 2976 patients were included for analysis with 1701 patients designated as pre-COVID and 1275 as post-COVID. The pre-COVID cohort had fewer patients undergoing revision surgery (16.8% vs 21.9%, P < 0.001) and a lower home discharge rate (84.5% vs 88.2%, P = 0.008). Inpatient complication (9.9% vs 9.2%, P = 0.562), inpatient mortality (0.1% vs 0.2%, P = 0.193), 90-day readmission (3.4% vs 3.2%, P = 0.828), and 90-day mortality rates (0.8% vs 0.8%, P = 0.902) were similar between groups. Patients with positive COVID-19 tests before surgery had similar complication rates (7.7% vs 6.1%, P = 1.000) as those without a positive test documented. CONCLUSIONS: After the emergence of COVID-19, patients undergoing spine surgery had a greater number of medical comorbidities, but similar rates of inpatient complications, readmission, and mortality. Prior COVID-19 infection was not associated with an increased risk of postsurgical complications or mortality. LEVEL OF EVIDENCE: Level III.

The Inhibitory Effect of NSAIDs and Opioids on Spinal Fusion: An animal model.

STUDY DESIGN: Translational Research. OBJECTIVE: To evaluate the relative effects of NSAIDs, opioids, and a combination of the two on spinal fusion inhibition in a rodent model. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids are common postoperative analgesic agents. Since NSAIDs inhibit the cyclooxygenase (COX) pathway they are seldom prescribed following spinal fusion. Opioids may be given instead, but recent evidence suggests opioids also adversely affect spinal fusion quality and success. METHODS: Eighty male Sprague-Dawley rats underwent L4-5 posterior lumbar fusion and were given one of the following analgesia regimens: saline, morphine (6 mg/kg), ketorolac (4 mg/kg), or morphine (3 mg/kg) and ketorolac (2 mg/kg). Serum samples were drawn to evaluate systemic pro-osteoblastic cytokines and vascular endothelial growth factor-A (VEGF-A) levels, which were measured via enzyme-linked immunosorbent assays (ELISA). After six weeks, the rats were sacrificed and the operated spinal segments underwent manual palpation, microCT, and histological analysis. RESULTS: Manual palpation scores were significantly diminished in the opioid, NSAID, and multimodal groups when compared to control (P<0.001). MicroCT fusion scores (P<0.001) and fusion rates (control: 75% vs. NSAID: 35% vs. opioid: 0% vs. combination: 15%, P<0.001) were significantly diminished in the treatment groups. The bone volume (BV) to tissue volume (TV) ratio (BV/TV) (P<0.001) and bone mineral density (BMD) (P<0.001) were all lower in the treatment groups with the opioid and combined groups having the lowest BMD. Although statistically insignificant (P<0.09), the concentration of VEGF-A was greater in the control group compared to opioids, NSAIDs, and the combined group. CONCLUSION: Opioids and NSAIDs, both independently and combined, inhibited spinal fusion and caused inferior bony callus. Administration of opioids resulted in the lowest rate of spinal fusion. We propose this may be due to the inhibition of VEGF-A, which limits angiogenesis to the burgeoning fusion mass.

Does Operative Level Impact Dysphagia Severity After Anterior Cervical Discectomy and Fusion?: A Multicenter Prospective Analysis.

STUDY DESIGN: Prospective multicenter cohort study. OBJECTIVE: To explore the association between operative level and postoperative dysphagia after anterior cervical discectomy and fusion (ACDF). BACKGROUND: Dysphagia is common after ACDF and has several risk factors, including soft tissue edema. The degree of prevertebral soft tissue edema varies based on the operative cervical level. However, the operative level has not been evaluated as a source of postoperative dysphagia. PATIENTS AND METHODS: Adult patients undergoing elective ACDF were prospectively enrolled at 3 academic centers. Dysphagia was assessed using the Bazaz Questionnaire, Dysphagia Short Questionnaire, and Eating Assessment Tool-10 (EAT-10) preoperatively and at 2, 6, 12, and 24 weeks postoperatively. Patients were grouped based on the inclusion of specific surgical levels in the fusion construct. Multivariable regression analyses were performed to evaluate the independent effects of the number of surgical levels and the inclusion of each particular level on dysphagia symptoms. RESULTS: A total of 130 patients were included. Overall, 24 (18.5%) patients had persistent postoperative dysphagia at 24 weeks and these patients were older, female, and less likely to drink alcohol. There was no difference in operative duration or dexamethasone administration. Patients with persistent dysphagia were significantly more likely to have C4-C5 included in the fusion construct (62.5% vs . 34.9%, P = 0.024) but there were no differences based on the inclusion of other levels. On multivariable regression, the inclusion of C3-C4 or C6-C7 was associated with more severe EAT-10 (ß: 9.56, P = 0.016 and ß: 8.15, P = 0.040) and Dysphagia Short Questionnaire (ß: 4.44, P = 0.023 and (ß: 4.27, P = 0.030) at 6 weeks. At 12 weeks, C3-C4 fusion was also independently associated with more severe dysphagia (EAT-10 ß: 4.74, P = 0.024). CONCLUSION: The location of prevertebral soft tissue swelling may impact the duration and severity of patient-reported dysphagia outcomes at up to 24 weeks postoperatively. In particular, the inclusion of C3-C4 and C4-C5 into the fusion may be associated with dysphagia severity.

A Standardized Curriculum Improves Trainee Rod Bending Proficiency in Spinal Deformity Surgery. Results of a Prospective Randomized Controlled Educational Study.

INTRODUCTION: Surgical simulation is increasingly being accepted as a training platform to promote skill development and a safe surgical technique. Preliminary investigations in spine surgery show that simulation paired with educational intervention can markedly improve trainee performance. This study used a newly developed thoracolumbar fusion rod bending model to assess the effect of a novel educational curriculum and simulator training on surgical trainee rod bending speed and proficiency. METHODS: Junior (PGY1 to 2) and senior (PGY3-fellow) surgical trainees at a single academic institution were prospectively enrolled in a rod bending simulation using a T7-pelvis spinal fusion model. Participants completed two simulations, with 1 month between first and second attempts. Fifty percent of surgeons in each training level were randomized to receive an educational curriculum (rod bending technique videos and unlimited simulator practice) between simulation attempts. Rod bending simulation proficiency was determined by the percentage of participants who completed the task (conclusion at 20 minutes), time to task completion or conclusion, and number of incomplete set screws at task conclusion. Participants completed a preparticipation and postparticipation survey. Univariate analysis compared rod bending proficiency and survey results between education and control cohorts. RESULTS: Forty trainees (20 junior and 20 senior) were enrolled, with 20 participants randomized to the education and control cohorts. No notable differences were observed in the first simulation rod bending proficiency or preparticipation survey results between the education and control cohorts. In the second simulation, the education versus the control cohort demonstrated a significantly higher completion rate ( P = 0.01), shorter task time ( P = 0.009), fewer incomplete screws ( P = 0.003), and greater experience level ( P = 0.008) and comfort level ( P = 0.002) on postparticipation survey. DISCUSSION: Trainees who participated in a novel educational curriculum and simulator training relative to the control cohort improved markedly in rod bending proficiency and comfort level. Rod bending simulation could be incorporated in existing residency and fellowship surgical skills curricula. LEVEL OF EVIDENCE: I.

Inhibition of Neurogenic Inflammatory Pathways Associated with the Reduction in Discogenic Back Pain.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to determine whether the initiation of anti-calcitonin gene-related peptide (CGRP inhibitor) medication therapy for migraines was also associated with improvements in back/neck pain, mobility, and function in a patient population with comorbid degenerative spinal disease and migraine. OVERVIEW OF LITERATURE: CGRP upregulates pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, brain-derived neurotrophic factor, and nerve growth factor in spinal spondylotic disease, which results in disc degeneration and sensitization of nociceptive neurons. Although CGRP inhibitors can quell neurogenic inflammation in migraines, their off-site efficacy as a therapeutic target for discogenic back/neck pain conditions remains unknown. METHODS: All adult patients diagnosed with spinal spondylosis and migraine treated with CGRP inhibitors at a single academic institution between 2017 and 2020 were retrospectively identified. Patient demographic and medical data, follow-up duration, migraine severity and frequency, spinal pain, functional status, and mobility before and after the administration of CGRP inhibitors were collected. Paired univariate analysis was conducted to determine significant changes in spinal pain, headache severity, and headache frequency before and after the administration of CGRP inhibitors. The correlation between changes in the spinal pain score and functional or mobility improvement was assessed with Spearman's rho. RESULTS: In total, 56 patients were included. The mean follow-up time after the administration of CGRP inhibitors was 123 days for spinal pain visits and 129 days for migraine visits. Back/neck pain decreased significantly (p <0.001) from 6.30 to 4.36 after starting CGRP inhibitor therapy for migraine control. As recorded in the spine follow-up notes, 25% of patients experienced a functional improvement in the activities of daily living, and 17.5% experienced mobility improvement while taking CGRP inhibitors. Change in back/ neck pain moderately correlated (ρ=-0.430) with functional improvement but was not correlated with mobility improvement (ρ=-0.052). CONCLUSIONS: Patients taking CGRP inhibitors for chronic migraines with comorbid degenerative spinal conditions experienced significant off-target reduction of back/neck pain.

Reimbursement of Lumbar Fusion at an Orthopaedic Specialty Hospital Versus Tertiary Referral Center.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVE: To explore the differences in Medicare reimbursement for lumbar fusion performed at an orthopaedic specialty hospital (OSH) and a tertiary referral center and to elucidate drivers of Medicare reimbursement differences. SUMMARY OF BACKGROUND DATA: To provide more cost-efficient care, appropriately selected patients are increasingly being transitioned to OSHs for lumbar fusion procedures. There are no studies directly comparing reimbursement of lumbar fusion between tertiary referral centers (TRC) and OSHs. METHODS: Reimbursement data for a tertiary referral center and an orthopaedic specialty hospital were compiled through the Centers for Medicare and Medicaid Services. Any patient with lumbar fusions between January 2014 and December 2018 were identified. OSH patients were matched to TRC patients by demographic and surgical variables. Outcomes analyzed were reimbursement data, procedure data, 90-day complications and readmissions, operating room times, and length of stay (LOS). RESULTS: A total of 114 patients were included in the final cohort. The tertiary referral center had higher post-trigger ($13,554 vs. $8,541, P<0.001) and total episode ($49,973 vs. $43,512, P<0.010) reimbursements. Lumbar fusion performed at an OSH was predictive of shorter OR time (ß=0.77, P<0.001), shorter procedure time (ß=0.71, P<0.001), and shorter LOS (ß=0.53, P<0.001). There were no significant differences in complications (9.21% vs. 15.8%, P=0.353) or readmission rates (3.95% vs. 7.89%, P=0.374) between the 2 hospitals; however, our study is underpowered for complications and readmissions. CONCLUSION: Lumbar fusion performed at an OSH, compared with a tertiary referral center, is associated with significant Medicare cost savings, shorter perioperative times, decreased LOS, and decreased utilization of post-acute resources. LEVEL OF EVIDENCE: 3.

Preoperative Opioid Prescribers and Lumbar Fusion: Their Effect on Clinical Outcomes and Postoperative Opioid Usage.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the impact of multiple preoperative opioid prescribers on postoperative patient opioid usage and patient-reported outcome measures after single-level lumbar fusion. SUMMARY OF BACKGROUND DATA: Prior literature has identified opioid prescriptions from multiple postoperative providers increase opioid usage rates. However, there is limited evidence on how multiple preoperative opioid prescribers affect postoperative opioid usage or clinical outcomes after a single-level lumbar fusion. PATIENTS AND METHODS: A retrospective review of single-level transforaminal lumbar interbody fusion or posterolateral lumbar fusions between September 2017 and February 2020 at a single academic institution was performed. Patients were excluded if they were not identifiable in our state's prescription drug-monitoring program. Univariate comparisons and regression analyses identified factors associated with postoperative clinical outcomes and opioid usage. RESULTS: Of 239 patients, 160 (66.9%) had one or fewer preoperative prescribers and 79 (33.1%) had >1 prescribers. On regression analysis, the presence of multiple preoperative prescribers was an independent predictor of increased improvement in Visual Analog Scale (∆VAS) Back (ß=-1.61, P =0.012) and the involvement of a nonoperative spine provider was an independent predictor of increased improvement in ∆VAS Leg (ß = -1.53, P = 0.034). Multiple preoperative opioid prescribers correlated with an increase in opioid prescriptions postoperatively (ß = 0.26, P = 0.014), but it did not significantly affect the amount of morphine milligram equivalents prescribed (ß = -48.79, P = 0.146). A greater number of preoperative opioid prescriptions predicted worse improvements in VAS Back, VAS Leg, and Oswestry Disability Index and predicted increased postoperative opioid prescriptions, prescribers, and morphine milligram equivalents. CONCLUSIONS: Multiple preoperative opioid prescribers predicted increased improvement in postoperative back pain, whereas preoperative involvement of a nonoperative spine provider predicted improvements in leg pain after surgery. The number of preoperative opioid prescriptions was a better metric for predicting poor postoperative outcomes and increased opioid consumption compared with the number of preoperative opioid prescribers.

Validation of the AO Spine Thoracolumbar Injury Classification System Treatment Algorithm: Should it be used to Guide Fracture Management?

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVE: To determine how historical management of thoracolumbar spine injuries compares to the recently proposed AO Spine Thoracolumbar Injury Classification System treatment algorithm. SUMMARY OF BACKGROUND DATA: Classifications of the thoracolumbar spine are not uncommon. The frequent advent of new classifications is typically due to previous classifications being primarily descriptive or unreliable. Thus, AO Spine created a classification with an associated treatment algorithm to guide injury classification and management. METHODS: Thoracolumbar spine injuries were retrospectively identified from a prospectively collected spine trauma database at a single, urban, academic medical center during the years 2006 to 2021. Each injury was classified and assigned points based on the AO Spine Thoracolumbar Injury Classification System injury severity score. Patients were grouped into scores of 3 or less (preferred initial conservative treatment) and greater than 6 (preferred initial surgical intervention). Either operative or non-operative treatment was considered appropriate for injury severity scores of 4 or 5. RESULTS: A total of 815 patients (TL AOSIS 0-3: 486, TL AOSIS 4-5: 150, TL AOSIS 6+: 179) met inclusion status. Injury severity scores of 0-3 were more likely to undergo non-operative management compared to scores of 4-5 or 6+ (99.0% vs. 74.7% vs. 13.4%, P <0.001). Thus, guideline congruent treatment was 99.0%, 100%, and 86.6%, respectively ( P <0.001). Most injuries determined to be a 4 or 5 were treated non-operatively (74.7%). Based on the treatment algorithm, 97.5% of patients who received operative treatment and 96.1% who received non-operative treatment were managed in accordance with the algorithm. Of the 29 patients who did not receive algorithm congruent treatment, 5 (17.2%) were treated surgically. CONCLUSIONS: A retrospective review of thoracolumbar spine injuries at our urban academic medical center identified that patients are historically treated in accordance with the proposed AO Spine Thoracolumbar Injury Classification System treatment algorithm.

Patient-specific Risk Factors Increase Episode of Care Costs After Lumbar Decompression.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To determine, which patient-specific risk factors increase total episode of care (EOC) costs in a population of Centers for Medicare and Medicaid Services beneficiaries undergoing lumbar decompression. SUMMARY OF BACKGROUND DATA: Lumbar decompression is an effective option for the treatment of central canal stenosis or radiculopathy in patients unresponsive to nonoperative management. Given that elderly Americans are more likely to have one or more chronic medical conditions, there is a need to determine, which, if any, patient-specific risk factors increase health care costs after lumbar decompression. METHODS: Care episodes limited to lumbar decompression surgeries were retrospectively reviewed on a Centers for Medicare and Medicaid Service reimbursement database at our academic institution between 2014 and 2019. The 90-day total EOC reimbursement payments were collected. Patient electronic medical records were then matched to the selected care episodes for the collection of patient demographics, medical comorbidities, surgical characteristics, and clinical outcomes. A stepwise multivariate linear regression model was developed to predict patient-specific risk factors that increased total EOC costs after lumbar decompression. Significance was set at P <0.05. RESULTS: A total of 226 patients were included for analysis. Risk factors associated with increased total EOC cost included increased age (per year) (ß = $324.70, P < 0.001), comorbid depression (ß = $4368.30, P = 0.037), revision procedures (ß = $6538.43, P =0.012), increased hospital length of stay (per day) (ß = $2995.43, P < 0.001), discharge to an inpatient rehabilitation facility (ß = $14,417.42, P = 0.001), incidence of a complication (ß = $8178.07, P < 0.001), and readmission (ß = $18,734.24, P < 0.001) within 90 days. CONCLUSIONS: Increased age, comorbid depression, revision decompression procedures, increased hospital length of stay, discharge to an inpatient rehabilitation facility, and incidence of a complication and readmission within 90 days were all associated with increased total episodes of care costs.

Varenicline mitigates the increased risk of pseudarthrosis associated with nicotine.

BACKGROUND CONTEXT: High serum nicotine levels increase the risk of nonunion after spinal fusion. Varenicline, a pharmaceutical adjunct for smoking cessation, is a partial agonist designed to displace and outcompete nicotine at its receptor binding site, thereby limiting downstream activation. Given its mechanism, varenicline may have therapeutic benefits in mitigating nonunion for active smokers undergoing spinal fusion. PURPOSE: To compare fusion rate and fusion mass characteristics between cohorts receiving nicotine, varenicline, or concurrent nicotine and varenicline after lumbar fusion. STUDY DESIGN: Rodent noninstrumented spinal fusion model. METHODS: Sixty eight-week-old male Sprague-Dawley rats weighing approximately 300 grams underwent L4-5 posterolateral fusion (PLF) surgery. Four experimental groups (control: C, nicotine: N, varenicline: V, and combined: NV [nicotine and varenicline]) were included for analysis. Treatment groups received nicotine, varenicline, or a combination of nicotine and varenicline delivered through subcutaneous osmotic pumps beginning two weeks before surgery until the time of sacrifice at age 14 weeks. Manual palpation testing, microCT imaging, bone histomorphometry, and biomechanical testing were performed on harvested spinal fusion segments. RESULTS: Control (p=0.016) and combined (p=0.032) groups, when compared directly to the nicotine group, demonstrated significantly greater manual palpation scores. The fusion rate in the control (93.3%) and combined (93.3%) groups were significantly greater than that of the nicotine group (33.3%) (p=0.007, both). Biomechanical testing demonstrated greater Young's modulus of the fusion segment in the control (17.1 MPa) and combined groups (34.5 MPa) compared to the nicotine group (8.07 MPa) (p<0.001, both). MicroCT analysis demonstrated greater bone volume fraction (C:0.35 vs N:0.26 vs NV:0.33) (p<0.001, all) and bone mineral density (C:335 vs N:262 vs NV:328 mg Ha/cm3) (p<0.001, all) in the control and combined groups compared to the nicotine group. Histomorphometry demonstrated a greater mineral apposition rate in the combined group compared to the nicotine group (0.34 vs 0.24 µm/day, p=0.025). CONCLUSION: In a rodent spinal fusion model, varenicline mitigates the adverse effects of high nicotine serum levels on the rate and quality of spinal fusion. CLINICAL SIGNIFICANCE: These findings have the potential to significantly impact clinical practice guidelines and the use of pharmacotherapy for active nicotine users undergoing fusion surgery.

Effect of Clinical and Radiographic Degenerative Spondylolisthesis Classification on Patient-reported Outcomes and Spinopelvic Parameters for Patients With Single-level L4-L5 Degenerative Spondylolisthesis After Lumbar Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To determine whether preoperative clinical and radiographic degenerative spondylolisthesis (CARDS) classification is associated with differences in patient-reported outcomes and spinopelvic parameters after posterior decompression and fusion for L4-L5 degenerative spondylolisthesis (DS). SUMMARY: The CARDS classification for lumbar DS, an alternative to the Meyerding system, considers additional radiographic findings such as disc space collapse and segmental kyphosis and stratifies DS into 4 radiographically distinct classes. Although CARDS has been shown to be a reliable and reproducible method for classifying DS, very few studies have assessed whether the CARDS types represent distinct clinical entities. PATIENTS AND METHODS: A retrospective cohort analysis was conducted on patients with L4-L5 DS who underwent posterior lumbar decompression and fusion. Changes in spinopelvic alignment and patient-reported outcomes measures, including recovery ratios and percentage of patients achieving the minimal clinically important difference, were compared among patients in each CARDS classification 1-year postoperatively using analysis of variance or Kruskal-Wallis H with Dunn post hoc analysis. Multiple linear regression determined whether CARDS groups significantly predicted patient-reported outcomes measures, lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL) while controlling for demographic and surgical characteristics. RESULTS: Preoperative type B spondylolisthesis predicted decreased improvement in "physical component and mental component score of the short form-12" compared with type A spondylolisthesis (ß-coefficient = -5.96, P = 0.031) at 1 year. Significant differences were found between CARDS groups with regards to ΔLL (A: -1.63 degrees vs B: -1.17 degrees vs C: 2.88 degrees vs D: 3.19 degrees, P = 0.010) and ΔPI-LL (A: 1.02 degrees vs B: 2.09 degrees vs C: -2.59 degrees vs D: -3.70 degrees, P = 0.012). Preoperative type C spondylolisthesis was found to predict increased LL (ß-coefficient = 4.46, P = 0.0054) and decreased PI-LL (ß-coefficient = -3.49, P = 0.025) at 1 year compared with type A spondylolisthesis. CONCLUSIONS: Clinical and radiographic outcomes differed significantly by preoperative CARDS classification type for patients undergoing posterior decompression and fusion for L4-L5 DS. LEVEL OF EVIDENCE: Level III.

Spine Surgical Subspecialty and Its Effect on Patient Outcomes: A Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To perform a systematic review and meta-analysis to identify if intraoperative or postoperative differences in outcomes exist between orthopedic and neurological spine surgeons. SUMMARY OF BACKGROUND DATA: Spine surgeons may become board certified through orthopedic surgery or neurosurgical residency training, and recent literature has compared surgical outcomes between surgeons based on residency training background with conflicting results. MATERIALS AND METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a search of PubMed and Scopus databases was conducted and included articles comparing outcomes between orthopedic spine surgeons and neurosurgeons. The Newcastle-Ottawa scale was used to determine the quality of studies. Forest plots were generated using mean differences (MD) for continuous variables and odds ratios (OR) for binomial variables, and 95% CI was reported. RESULTS: Of 615 search term results, 16 studies were identified for inclusion. Evaluation of the studies found no differences in readmission rates [OR, ref: orthopedics: 0.99 (95% CI: 0.901, 1.09); I2 = 80%], overall complication rates [OR, ref: orthopedics: 1.03 (95% CI: 0.97, 1.10); I2 = 70%], reoperation rates [OR, ref: orthopedics: 0.91 (95% CI: 0.82, 1.00); I2 = 86%], or overall length of hospital stay between orthopedic spine surgeons and neurosurgeons [MD: -0.19 days (95% CI: -0.38, 0.00); I2 = 98%]. However, neurosurgeons ordered a significantly lower rate of postoperative blood transfusions [OR, ref: orthopedics: 0.49 (95% CI: 0.41, 0.57); I2 = 75%] while orthopedic spine surgeons had shorter operative times [MD: 14.28 minutes, (95% CI: 8.07, 20.49), I2 = 97%]. CONCLUSIONS: Although there is significant data heterogeneity, our meta-analysis found that neurosurgeons and orthopedic spine surgeons have similar readmission, complication, and reoperation rates regardless of the type of spine surgery performed.

Validation of the Hierarchical Nature of the AO Spine Sacral Classification and the Development of the Sacral AO Spine Injury Score.

STUDY DESIGN: Global cross-sectional survey. OBJECTIVE: The objective of this study was to validate the hierarchical nature of the AO Spine Sacral Classification System and develop an injury scoring system. SUMMARY OF BACKGROUND DATA: Although substantial interobserver and intraobserver reliability of the AO Spine Sacral Classification System has been established, the hierarchical nature of the classification has yet to be validated. METHODS: Respondents numerically graded each variable within the classification system for severity. Based on the results, a Sacral AO Spine Injury Score (AOSIS) was developed. RESULTS: A total of 142 responses were received. The classification exhibited a hierarchical Injury Severity Score (ISS) progression (A1: 8 to C3: 95) with few exceptions. Subtypes B1 and B2 fractures showed no significant difference in ISS (B1 43.9 vs. B2 43.4, P =0.362). In addition, the transitions A3→B1 and B3→C0 represent significant decreases in ISS (A3 66.3 vs. B1 43.9, P <0.001; B3 64.2 vs. C0 46.4, P <0.001). Accordingly, A1 injury was assigned a score of 0. A2 and A3 received scores of 1 and 3 points, respectively. Posterior pelvic injuries B1 and B2 both received a score of 2. B3 received a score of 3 points. C0, C1, C2, and C3 received scores of 2, 3, 5, and 6 points, respectively. The scores assigned to neurological modifiers N0, N1, N2, N3, and NX were 0, 1, 2, 4, and 3, respectively. Case-specific modifiers M1, M2, M3, and M4 received scores of 0, 0, 1, and 2 points, respectively. CONCLUSIONS: The results of this study validate the hierarchical nature of the AO Spine Sacral Classification System. The Sacral AOSIS sets the foundation for further studies to develop a universally accepted treatment algorithm for the treatment of complex sacral injuries. LEVEL OF EVIDENCE: Level IV-Diagnostic.

Trends in Short Construct Lumbar Fusions Over the Past Decade at a Single Institution.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: (1) To compare the rates of fusion techniques over the last decade; (2) to identify whether surgeon experience affects a surgeon's preferred fusion technique; (3) to evaluate differences in complications, readmissions, mortality, and patient-reported outcomes measures (PROMs) based on fusion technique. SUMMARY OF BACKGROUND DATA: Database studies indicate the number of lumbar fusions have been steadily increasing over the last two decades; however, insufficient granularity exists to detect if surgeons' preferences are altered based on additive surgical experience. METHODS: A retrospective review of continuously collected patients undergoing lumbar fusion at a single urban academic center was performed. Rates of lumbar fusion technique: posterolateral decompression fusion (PLDF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion + PLDF (ALIF), and lateral lumbar interbody fusion + PLDF (LLIF) were recorded. Inpatient complications, 90-day readmission, and inpatient mortality were compared with χ 2 test and Bonferroni correction. The Δ 1-year PROMs were compared with the analysis of variance. RESULTS: Of 3938 lumbar fusions, 1647 (41.8%) were PLDFs, 1356 (34.4%) were TLIFs, 885 (21.7%) were ALIFs, and 80 (2.0%) were lateral lumbar interbody fusions. Lumbar fusion rates increased but interbody fusion rates (2012: 57.3%; 2019: 57.6%) were stable across the study period. Surgeons with <10 years of experience performed more PLDFs and less ALIFs, whereas surgeons with >10 years' experience used ALIFs, TLIFs, and PLDFs at similar rates. Patients were more likely to be discharged home over the course of the decade (2012: 78.4%; 2019: 83.8%, P <0.001). No differences were observed between the techniques in regard to inpatient mortality ( P =0.441) or Δ (postoperative minus preoperative) PROMs. CONCLUSIONS: Preferred lumbar fusion technique varies by surgeon preference, but typically remains stable over the course of a decade. The preferred fusion technique did not correlate with differences in PROMs, inpatient mortality, and patient complication rates. LEVELS OF EVIDENCE: 3-treatment.

Facet Distraction and Dysphagia: A Prospective Evaluation of This Common Postoperative Issue Following Anterior Cervical Spine Surgery.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: Our primary study was to investigate whether the degree of postoperative facet and disk space distraction following anterior cervical discectomy and fusion (ACDF) affects the rate of postoperative dysphagia. SUMMARY OF BACKGROUND DATA: Although ACDF is safe and well tolerated, postoperative dysphagia remains a common complication. Intervertebral disk space distraction is necessary in ACDF to visualize the operative field, prepare the endplates for fusion, and facilitate graft insertion. However, the degree of distraction tolerated, before onset of dysphagia, is not well characterized ACDF. MATERIALS AND METHODS: A prospective cohort study was conducted of 70 patients who underwent ACDF between June 2018 and January 2019. Two independent reviewers measured all preoperative and postoperative radiographs measured for interfacet distraction distance and intervertebral distraction distance, with intrareviewer reproducibility measurements after one month. For multilevel surgery, the level with the greatest distraction was measured. Primary outcomes were numerical dysphagia (0-10), Eating Assessment Tool 10, and Dysphagia Symptom Questionnaire score collected at initial visit and two, six, 12, and 24 weeks postoperatively. RESULTS: A total of 70 patients were prospectively enrolled, 59 of whom had adequate radiographs. An average of 1.71 (SD: 0.70) levels were included in the ACDF construct. Preoperatively, 13.4% of patients reported symptoms of dysphagia, which subsequently increased in the postoperative period at through 12 weeks postoperatively, before returning to baseline at 24 weeks. Intrareviewer and interreviewer reliability analysis demonstrated strong agreement. There was no relationship between interfacet distraction distance/intervertebral distraction distance and dysphagia prevalence, numerical rating, Eating Assessment Tool 10, or Dysphagia Symptom Questionnaire. CONCLUSIONS: Patients who had an ACDF have an increased risk of dysphagia in the short term, however, this resolved without intervention by six months. Our data suggests increased facet and intervertebral disk distraction does not influence postoperative dysphagia rates. LEVEL OF EVIDENCE: 3.

Clinical Improvements in Myelopathy Result in Improved Patient-Reported Outcomes Following Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine if myelopathy severity predicted the magnitude of improvement in health-related quality of life metrics following anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Surgery for myelopathy is primarily performed to halt disease progression. However, it is still controversial if these patients can expect significant health-related quality-of life improvements following ACDF. We explore the relationship between modified Japanese Orthopaedic Association (mJOA) improvements and its effect on other health-related quality-of life metrics. MATERIALS AND METHODS: Patients undergoing ACDF for myelopathy were grouped based on preoperative mJOA scores into mild (15-17), moderate (12-14), and severe (<12) groups. Patients were subsequently categorized based on if they attained the minimum clinically detectable improvement (MCID) threshold for mJOA. Multivariate linear regression was performed to determine the magnitude of improvement in ∆patient-reported outcome measures. RESULTS: A total of 374 patients were identified for inclusion. Of those, 169 (45.2%) had mild myelopathy, 125 (33.4%) had moderate, and 80 (21.4%) had severe myelopathy. Only the moderate and severe groups had significant improvements in mJOA following surgery (mild: P =0.073, moderate: P <0.001, severe: P <0.001). There were no significant differences in the magnitude of improvement for any patient-reported outcome measure based on myelopathy severity, except for mJOA (mild: 0.27, moderate: 1.88, severe: 3.91; P <0.001). Patients meeting the MCID for mJOA had better ∆Short-Form 12 Mental Component Score (3.29 vs. -0.21, P =0.007), ∆Short-Form 12 Physical Component Score (6.82 vs. 1.96, P <0.001), ∆Visual Analog Scale Neck (-3.11 vs. -2.17, P =0.001), ∆Visual Analog Scale Arm (-2.92 vs. -1.48, P <0.001), ∆Neck Disability Index (-18.35 vs. -7.86, P <0.001), and ∆mJOA (3.38 vs. -0.56, P <0.001) compared with patients who did not. CONCLUSIONS: Worse baseline myelopathy severity predicts worse postoperative outcomes. However, baseline myelopathy severity is not predictive of the magnitude of postoperative improvement with the exception of mJOA. Patients who attain MCID improvement in mJOA had greater postoperative improvement for other health-related quality of life metrics.