Rates of Future Lumbar Fusion in Patients with Cauda Equina Syndrome Treated With Decompression.

INTRODUCTION: The long-term risk of conversion to lumbar fusion is ill-defined for patients with cauda equina syndrome (CES) treated with decompression. This study aimed to identify the rates of fusion in patients with CES and compare those rates with a matched lumbar spinal stenosis (LSS) group. METHODS: Patients with CES who underwent decompression were identified in a national database and matched to control patients with LSS. The rates of conversion to fusion were identified and compared. Multivariate logistic regression analysis identified independently associated risk factors. A subanalysis was conducted after stratifying by timing between CES diagnosis and decompression. RESULTS: The rate of lumbar fusion in the CES cohort was 3.6% after 1 year, 6.7% after 3 years, and 7.8% after 5 years, significantly higher than the LSS control group at all time points (1 year: 1.6%, P = 0.001; 3 years: 3.0%, P < 0.001; 5 years: 3.8%, P < 0.001). CES was independently associated with increased risk of conversion to fusion (odds ratio: 2.13; 95% confidence interval: 1.56 to 2.97; P < 0.001). Surgical timing was not associated with risk of conversion to fusion. CONCLUSIONS: After 5 years, 7.8% of patients with CES underwent fusion, a markedly higher rate compared with patients with LSS. Counseling patients with CES on this increased risk of future surgery is important for patient education and satisfaction.

Analysis of the Cost and Efficacy of Intra-Articular Knee Injections.

INTRODUCTION: Intra-articular joint injections have been used with the goal of providing patients with symptomatic relief. Recently, however, the efficacy of corticosteroid (CS) and hyaluronic acid (HA) injections in the management of knee osteoarthritis (OA) is questionable. In this analysis, we investigated the costs associated with injections by assessing overall use, conversion and average time to total knee arthroplasty (TKA), and reimbursement. METHODS: Patients aged 50 to 70 years with a knee-related diagnosis of pain, effusion, or OA were identified in the Humana insurance national data set. Patients who received intra-articular injections were stratified by the type and number of injection(s) received. The subsequent rates of TKA were compared with Kaplan-Meier curves for patients who underwent CS injections, HA injections, and a benchmarking cohort of patients with OA and no history of knee injections in the medical record. Average time to TKA was determined from index diagnosis, and total cost was compared using Wilcoxon rank sum analyses. RESULTS: A total of 778,686 patients were identified. Of these, 637,112 had no knee injection history, while 124,129 received CS and 17,445 received HA injections. The 10-year conversion to TKA was highest in HA cohort (31.6%), followed by the CS cohort (24.0%) and the noninjection cohort (7.3%) (P < 0.001). Time to TKA increased with number of injections for both injection types. For patients who underwent TKA, median cost was greater in HA ($16,687) and CS ($15,563) cohorts relative to noninjection cohort ($14,733) (P < 0.001). DISCUSSION: Compared with the noninjection cohort, both HA and CS cohorts experienced increased costs and increased time to TKA. However, while the cost incurred in HA cohort was greater than that in CS cohort, no appreciable benefit was demonstrated for conversion or time to TKA. Therefore, if intra-articular knee injections are indicated for the nonsurgical management of knee OA, the results of this study support CS over HA.

Does lumbar spine fusion predispose patients to future total hip replacement?

OBJECTIVE: Hip-spine syndrome has been well studied since it was first described by Offierski and MacNab in 1983. Today, strong evidence links symptoms of hip and spine pathology to postsurgical outcomes. Recent studies have reported increased rates of hip dislocation in patients previously treated with total hip arthroplasty (THA) who had undergone lumbar fusion procedures. However, the effect of this link on native hip-joint degeneration remains an area of ongoing research. The purpose of this study was to characterize the relationship between use of lumbar fusion procedures and acceleration of hip pathology by analyzing the rate of future THA in patients with preexisting hip osteoarthritis. METHODS: This population-level, retrospective cohort study was conducted by using the PearlDiver research program. The initial patient cohort was defined by the presence of diagnosis codes for hip osteoarthritis. Patients were categorized according to use of lumbar fusion after diagnosis of hip pathology. Survival curves with respect to THA were generated by comparison of the no lumbar fusion cohort with the lumbar fusion cohort. To assess the impact of fusion construct length, the lumbar fusion cohort was then stratified according to the number of levels treated (1-2, 3-7, or ≥ 8 levels). Hazard ratios (HRs) were then calculated for the risk factors of number of levels treated, patient age, and sex. RESULTS: A total of 2,275,683 patients matched the authors' inclusion criteria. Log-rank analysis showed no significant difference in the rates of THA over time between the no lumbar fusion cohort (2,239,946 patients) and lumbar fusion cohort (35,737 patients; p = 0.40). When patients were stratified according to number of levels treated, again no differences in the incidence rates of THA over the study period were determined (p = 0.30). Patients aged 70-74 years (HR 0.871, p < 0.001), 75-79 years (HR 0.733, p < 0.001), 80-84 years (HR 0.557, p < 0.001), and ≥ 85 years (HR = 0.275, p < 0.001) were less likely to undergo THA relative to the reference group (patients aged 65-69 years). CONCLUSIONS: Although lumbar fusion was initially hypothesized to have a significant effect on rate of THA, lumbar fusion was not associated with increased need for future THA in patients with preexisting hip osteoarthritis. Additionally, there was no relationship between fusion construct length and rate of THA. Although lumbar fusion reportedly increases the risk of hip dislocation in patients with prior THA, these data suggest that lumbar fusion may not clinically accelerate native hip degeneration.

The Injury Rate in National Football League Players Increased Following Cancellation of Preseason Games Because of COVID-19.

PURPOSE: To investigate the injury rate in National Football League (NFL) athletes during the first 4 weeks of the 2020 NFL season. METHODS: This study was a retrospective review of all NFL players who were placed on the injury report during the preseason and the first 4 weeks of the regular season from the 2016-2017 through the 2020-2021 NFL regular seasons. Players' dates of injury were cross-referenced with an absence of statistics from the respective games for which they were ruled out so as to ensure accuracy. Injury rates were calculated per 1,000 athletic exposures. Relative risk with 95% confidence intervals compared injury rates between the 2 cohorts. RESULTS: Over the course of the study period of 4 NFL seasons, 3,025 injuries were reported. Of the 3,025 injuries reported, 582 (19%) occurred during weeks 1-4 of the 2020-2021 regular season, whereas 1,292 (53%) occurred during preseason weeks 1-4, and 1,151 (38%) occurred during regular-season weeks 1-4 of NFL seasons 2016-2017, 2018-2019, and 2019-2020. There was a significant increase in the injury rate during weeks 1-4 of the 2020-2021 regular season for all comparisons with the injury rate both during the preseasons and the regular seasons of 3 recent past NFL seasons. CONCLUSIONS: The rate of injury in NFL players during weeks 1-4 of the 2020-2021 regular seasons was significantly higher than during 3 recent past NFL preseasons and regular seasons. LEVEL OF EVIDENCE: Level IV, diagnostic case series.

Long-term rates of bladder dysfunction after decompression in patients with cauda equina syndrome.

BACKGROUND CONTEXT: Cauda equina syndrome (CES) occurs due to compression of the lumbar and sacral nerve roots and is considered a surgical emergency. Although the condition is relatively rare, the associated morbidity can be devastating to patients. While substantial research has been conducted on the timing of treatment, the literature regarding long-term rates of bladder dysfunction in CES patients is scarce. PURPOSE: The aim of this study was to identify long-term rates of bladder dysfunction in CES patients and to compare those rates to non-CES patients who underwent similar spinal decompression. STUDY DESIGN/SETTING: Retrospective database study. PATIENT SAMPLE: The CES cohort was comprised of 2,362 patients who underwent decompression surgery following CES diagnosis with a 5-year follow-up. These patients were matched to 9,448 non-CES control patients who underwent spinal decompression without a diagnosis of CES. OUTCOME MEASURES: Diagnosis of bladder dysfunction, surgical procedure to address bladder dysfunction METHODS: Using the national insurance claims database, PearlDiver, CES patients who underwent decompression surgery were identified and 1:4 matched to non-CES patients who underwent similar spinal decompression surgery. The 1-year, 3-year, and 5-year rates of progression to a bladder dysfunction diagnosis and surgical intervention to manage bladder dysfunction were recorded. The CES and non-CES groups were compared with univariate testing, and an analysis of risk factors for bladder dysfunction was performed with multivariate logistic regression analysis. RESULTS: A total of 2,362 CES patients who underwent decompression surgery were identified and matched to 9,448 non-CES control patients. After 5 years, CES patients had a 10%-12% increased absolute risk of continued bladder dysfunction and a 0.7%-0.9% increased absolute risk of undergoing a surgical procedure for bladder dysfunction, as compared to matched non-CES patients. Multivariate analysis controlling for age, sex, obesity, tobacco use, and diabetes, identified CES as independently associated with increased 5-year risk for bladder dysfunction diagnosis (odds ratio [OR]: 1.72; 95% confidence interaval [CI] 1.56-1.89; p<.001) and procedure (OR: 1.40; 95% CI 1.07-1.81; p=.012). CONCLUSIONS: Understanding the long-term risk for bladder dysfunction in CES patients is important for the future care and counseling of patients. Compared to non-CES patients who underwent similar spinal decompression, CES patients were observed to have a significantly higher long-term likelihood for both bladder dysfunction diagnosis and urologic surgical procedure.

Comparing Bleeding and Thrombotic Rates in Spine Surgery: An Analysis of 119 888 Patients.

STUDY DESIGN: Retrospective, database review. OBJECTIVES: Examine the utilization rate of postoperative deep vein thrombosis (DVT) prophylaxis and compare the incidence and severity of bleeding and thrombotic complications in elective spine surgery patients. METHODS: We utilized PearlDiver, a national orthopedics claims database. All patients who underwent elective spine surgery from 2007 to 2017 were included. Patients were stratified by the presence of DVT prophylaxis drug codes, then by comorbidities for postoperative bleeding/thrombosis. The severity of all bleeding and thrombotic complications in each cohort was studied, including the incidence of complications requiring operative washout, diagnosis of pulmonary embolism, intensive care unit admission, and mortality. RESULTS: A total of 119 888 patients were included. The majority of patients (118 720, >99%) were not administered postoperative DVT chemoprophylaxis while a minority of patients (1168) were. The overall rates of bleeding and thrombotic complications within the population not receiving DVT prophylaxis were 1.96% and 2.45%, respectively (P < .001). The incidence of surgical intervention for a wound washout was 0.62% compared with 1.05% for pulmonary embolism (P < .001). Intensive care unit admission rates related to a wound washout procedure or pulmonary embolism also significantly differed (0.07% vs 0.34%, P < .001). There were no observed differences in mortality. When controlling for patient comorbidity, patients with atrial fibrillation, cancer, or a prior history of thrombotic complications experienced the greatest increased risks of postoperative thrombosis. CONCLUSIONS: DVT prophylaxis is not routinely utilized following elective spine procedures. We report that there exist specific populations which may receive benefit from these practices, although further study is necessary to determine optimal prevention strategies for both thrombotic and bleeding complications in spine surgery.

The Influence of Selective Serotonin Reuptake Inhibitors on Lumbar Arthrodesis.

STUDY DESIGN: Retrospective analysis using the PearlDiver national insurance claims database. OBJECTIVE: To investigate the relationship between chronic preoperative selective serotonin reuptake inhibitor (SSRI) prescriptions and nonunion following spine fusion surgery. SUMMARY OF BACKGROUND DATA: Contemporary literature has linked SSRIs to decreased bone mineral density and increased rates of future bone fracture. Furthermore, a recent murine model has suggested a potential role in the quality of fracture healing itself. METHODS: All single-level lumbar fusion patients were identified. The rate of nonunion diagnosis between 6 and 24 months following surgery was assessed. A stratified analysis of chronic SSRI use and a number of comorbidities was conducted, followed by a multiple logistic regression analysis of nonunion accounting for qualifying risk factors. Finally, subanalyses of individual procedure codes were carried out. RESULTS: In total, 7905 single-level lumbar fusion patients were included. In the multivariate analysis, chronic SSRI [odds ratio (OR): 1.558, P=0.004] and tobacco use (OR: 1.500, P=0.011) were identified as independent risk factors for nonunion, whereas patient age over 60 years (OR: 0.468, P<0.001) was observed to be negatively associated with nonunion. In the individual procedure subanalyses, SSRIs were significantly associated with nonunion in 2 of 3 univariate analyses and observed to be an independent risk factor for nonunion in 2 of the 3 procedure populations. CONCLUSIONS: These data suggest that patients treated concomitantly for mental health disorders with SSRIs before arthrodesis may be at an increased risk of postoperative nonunion. Closer follow-up may be indicated in this patient population.

Preoperative lumbar epidural steroid injections administered within 6 weeks of microdiscectomy are associated with increased rates of reoperation.

PURPOSE: Lumbar epidural steroid injections (LESIs) are widely utilized for back pain. However, as studies report adverse effects from these injections, defining a safe interval for their use preoperatively is necessary. We investigated the effects of preoperative LESI timing on the rates of recurrent microdiscectomy. METHODS: This study utilized the PearlDiver national insurance claims database. Microdiscectomy patients were stratified by the timing of their most recent LESI prior to surgery into bimonthly cohorts (0-2 months, 2-4 months, 4-6 months). This first cohort was further stratified into biweekly cohorts (0-2 weeks, 2-4 weeks, 4-6 weeks, 6-8 weeks). The 6-month reoperation rate was assessed and compared between each injection cohort and a control group of patients with no injections within 6 months before surgery. Univariate analyses of reoperation were conducted followed by multivariate analyses controlling for risk factors where appropriate. RESULTS: A total of 12,786 microdiscectomy patients were identified; 1090 (8.52%) received injections within 6 months before surgery. We observed a significant increase in the 6-month reoperation rates in patients who received injections within 6 weeks prior to surgery (odds ratio [OR] 1.900, 1.218-2.963; p = 0.005) compared to control. No other significant differences were observed. DISCUSSION: In this study, microdiscectomy performed within 6 weeks following LESIs was associated with a higher risk of reoperation, while microdiscectomy performed more than 6 weeks from the most recent LESI demonstrated no such association with increased risk. Further research into the interaction between LESIs and recurrent disk herniation is necessary.

The Effects of Chronic Preoperative Opioid Use on Single-level Lumbar Fusion Outcomes.

STUDY DESIGN: A retrospective study using a national insurance claims database. OBJECTIVE: The objective of this study was to assess the relationship between chronic preoperative opioids and the outcomes of revision surgery and nonunion after single-level lumbar fusion. SUMMARY OF BACKGROUND DATA: Opioids are widely utilized for pain management before spine procedures. Studies have associated opioids with unfavorable postoperative outcomes, and animal models have also linked opioid administration with unstable bone healing. METHODS: Single-level lumbar fusion patients were identified. Patients with any fracture history within 1 year before surgery were excluded. A chronic preoperative opioid cohort was defined by opioids prescriptions within 3 months prior and within 4-6 months before surgery. The rates of revision surgery within 6 months and nonunion within 6-24 months after surgery were assessed. Univariate analyses of chronic preoperative opioid prescriptions and various comorbidities for revision and nonunion were conducted followed by multivariate analyses controlling for these factors. Individual analyses were run for each of the 3 single-level lumbar fusion procedures. RESULTS: A total of 8494 single-level lumbar fusion patients were identified. Of the 3929 (46.3%) patients filled criteria for the chronic preoperative opioid cohort, while 3250 (38.3%) patients had no opioid prescriptions within 6 months before surgery. The opioid cohort experienced significantly higher rates of both revisions (3.92% vs. 2.71%, P=0.005) and nonunion (3.84% vs. 2.89%, P=0.027) relative to the opioid-naive cohort. In the multivariate analyses, chronic preoperative opioids were identified as an independent risk factor for revision (odds ratio: 1.453, P=0.006). CONCLUSIONS: We report that chronic opioid prescriptions before lumbar fusion may increase the risk of revision. Although these prescriptions were also associated with increased nonunion, the comparisons did not achieve statistical significance in the multivariate model. Chronic preoperative opioid use may be considered a potential risk factor in arthrodesis populations.

Chronic Opioid Use Is Associated With Surgical Site Infection After Lumbar Fusion.

STUDY DESIGN: Retrospective, database review. OBJECTIVE: The purpose of this study was to explore the association between preoperative opioid use and postoperative infection requiring operative wound washout in elective lumbar fusion patients. SUMMARY OF BACKGROUND DATA: Numerous peer-reviewed publications have conducted multivariate analyses of risk factors for surgical site infection. However, few have explored preoperative opioid use. Opioids have been widely prescribed preoperatively for pain management, but their effect on postsurgical infection is currently inconclusive. METHODS: We retrospectively queried the PearlDiver national insurance claims database and included patients from 2007 to 2017 with a history of lumbar fusion. Any interbody fusion history designated exclusion. We stratified patients by single or multilevel procedures and conducted univariate analyses of previously documented infection risk factors, as well as our variable of interest, chronic preoperative opioid use. Variables associated (P < 0.100) with the outcome measure of 90-day postoperative infection treated with operative irrigation and wound debridement were included in a multivariate analysis. RESULTS: A total of 12,519 patients matched our inclusion criteria. Among the single-level cohort, only diabetes was observed to be associated with infection requiring operative wound washout and thus no subsequent regression was performed. For the cohort of patients who underwent multilevel fusion, chronic opioid use, diabetes, congestive heart failure, chronic obstructive pulmonary disease, and hypertension trended toward significance in the univariate analysis and were included in a logistic regression model. In the multivariate analysis, chronic opioid use (odds ratio [OR] = 1.435, P = 0.025), diabetes (OR = 1.591 P = 0.003), and congestive heart failure (OR = 1.929, P = 0.003) were identified as independent risk factors for infection requiring operative wound washout. CONCLUSION: In this analysis, preoperative opioid use was significantly associated with infection requiring operative wound washout in multilevel lumbar fusion patients. Limiting opioid consumption may have the benefit of reducing the risk of infection following spine surgery. LEVEL OF EVIDENCE: 3.

Benchmarks of Duration and Magnitude of Opioid Consumption After Common Spinal Procedures: A Database Analysis of 47,823 Patients.

STUDY DESIGN: A retrospective cohort study performed in a nationwide insurance claims database. OBJECTIVE: This study aimed to examine duration and magnitude of postoperative opioid prescriptions following common spinal procedures. SUMMARY OF BACKGROUND DATA: Postoperative opioid prescription practices vary widely among providers and procedures and standards of care are not well-established. Previous work does not adequately quantify both duration and magnitude of opioid prescription. METHODS: Forty seven thousand eight hundred twenty three patients with record of any of four common spinal procedures in a nationwide insurance claims database were stratified by preoperative opioid use into three categories: "opioid naive," "sporadic user," or "chronic user," defined as 0, 1, or 2+ prescriptions filled in the 6 months preceding surgery. Those with record of subsequent surgery or readmission were excluded. Duration of opioid use was defined as the time between the index surgery and the last record of filling an opioid prescription. Magnitude of opioid use was defined as milligram morphine equivalents (MME) filled by 30 days post-op, converted to 5 mg oxycodone pills for interpretation. RESULTS: Opioid naive patients were less likely than chronic opioid users to fill any opioid prescription after surgery (63-68% naive vs. 91-95% chronic, P < 0.001), and when they did, their prescriptions were smaller in magnitude (76-91 pills naive vs. 127-152 pills chronic). One year after surgery, 15% to 18% of opioid naive and 50% to 64% of chronic opioid users continued filling prescriptions. CONCLUSION: Opioid naive patients use less postoperative opioids, and for a shorter period of time, than chronic users. This study serves as a normative benchmark for examining postoperative opioid use, which can assist providers in identifying patients with opioid dependence. Importantly, this work calls out the high risk of opioid exposure, as 15% to 18% of opioid naive patients continued filling opioid prescriptions 1 year after surgery. LEVEL OF EVIDENCE: 3.

Benchmarks of Duration and Magnitude of Opioid Consumption After Total Hip and Knee Arthroplasty: A Database Analysis of 69,368 Patients.

BACKGROUND: Opioid prescribing after orthopedic surgeries varies widely, and there is little consensus establishing proper standards of care. This retrospective cohort study examines opioid prescribing trends following total hip (THA) and knee (TKA) arthroplasty and evaluates preoperative opioid use as a predictor of duration and magnitude of postoperative opioid use. METHODS: Patients who underwent THA or TKA in a nationwide insurance database were stratified by preoperative opioid use. Naive, sporadic, and chronic users were defined as 0, 1, or 2+ prescriptions filled 6 months before surgery. Patients were excluded for readmission or subsequent surgery. Duration of opioid use was defined as time between the procedure and the last opioid prescription record, and magnitude of opioid use was defined as quantity of pills filled by 30 days postop. RESULTS: Naive patients were less likely than chronic users to fill any opioid prescription after surgery (THA: 61.5% naive vs 90.4% chronic, TKA: 72.0% naive vs 95.9% chronic), and they obtained fewer pills (THA: 73 pills naive vs 126 pills chronic, TKA: 86 pills naive vs 126 pills chronic, 5-mg oxycodone equivalent). Between 10% (THA) and 13% (TKA) of naive and between 47% (THA) and 62% (TKA) of chronic users continued opioid use at 1 year postop. CONCLUSION: Chronic users obtain more opioids postoperatively and continue filling prescriptions for longer than naive patients. This work benchmarks norms regarding opioid use and furthermore these data highlight the powerful effect of opioid exposure during surgery as 10%-13% of naive patients continued opioids at 1 year postop.

Cages in ACDF are Associated With a Higher Nonunion Rate Than Allograft: A Stratified Comparative Analysis of 6130 Patients.

STUDY DESIGN: A retrospective database review. OBJECTIVE: The purpose of this study was to analyze the rate of nonunion in patients treated with structural allograft and intervertebral cages in anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Existing literature consists primarily of single-center studies with inconsistent findings. METHODS: We performed a retrospective analysis of 6130 patients registered in the PearlDiver national database through Humana Insurance from 2007 to 2016. All ACDF patients with anterior plating who were active in the database for at least 1 year were included in the study. Patients with a fracture history within 1 year of intervention, past arthrodesis of hand, foot, or ankle, or a planned posterior approach were excluded from the study. Patients were stratified by number of levels treated, tobacco use, and diabetic condition. Nonunion rates of structural allograft and intervertebral cage groups after 1 year were compared using Chi-squared analyses. RESULTS: Four thousand sixty-three patients were included in the allograft group, while 2067 were included in the cage group. Overall nonunion rates were significantly higher in the cage group (5.32%) than in allograft group (1.97%) (P < 0.01). When controlling for confounders, increased rates of nonunion were consistently observed in the cage group, achieving statistical significance in 25 of the 26 analyses. CONCLUSION: The increased rate of nonunion associated with intervertebral cages may suggest the superiority of allograft over cages in ACDF. LEVEL OF EVIDENCE: 3.

The transmembrane domain of the p75 neurotrophin receptor stimulates phosphorylation of the TrkB tyrosine kinase receptor.

The function of protein products generated from intramembraneous cleavage by the γ-secretase complex is not well defined. The γ-secretase complex is responsible for the cleavage of several transmembrane proteins, most notably the amyloid precursor protein that results in Aß, a transmembrane (TM) peptide. Another protein that undergoes very similar γ-secretase cleavage is the p75 neurotrophin receptor. However, the fate of the cleaved p75 TM domain is unknown. p75 neurotrophin receptor is highly expressed during early neuronal development and regulates survival and process formation of neurons. Here, we report that the p75 TM can stimulate the phosphorylation of TrkB (tyrosine kinase receptor B). In vitro phosphorylation experiments indicated that a peptide representing p75 TM increases TrkB phosphorylation in a dose- and time-dependent manner. Moreover, mutagenesis analyses revealed that a valine residue at position 264 in the rat p75 neurotrophin receptor is necessary for the ability of p75 TM to induce TrkB phosphorylation. Because this residue is just before the γ-secretase cleavage site, we then investigated whether the p75(αγ) peptide, which is a product of both α- and γ-cleavage events, could also induce TrkB phosphorylation. Experiments using TM domains from other receptors, EGFR and FGFR1, failed to stimulate TrkB phosphorylation. Co-immunoprecipitation and biochemical fractionation data suggested that p75 TM stimulates TrkB phosphorylation at the cell membrane. Altogether, our results suggest that TrkB activation by p75(αγ) peptide may be enhanced in situations where the levels of the p75 receptor are increased, such as during brain injury, Alzheimer's disease, and epilepsy.