Is ABO blood type a risk factor for adjacent segment degeneration after lumbar spine fusion?

PURPOSE: This study aimed to explore associations between ABO blood type and postoperative adjacent segment degeneration/disease (ASD) following lumbar spine fusion, as well as evaluate differences in spinopelvic alignment, perioperative care, postoperative complications, and patient-reported outcome measures (PROMs). METHODS: An ambispective study was performed. Patients who underwent posterolateral or posterior lumbar interbody fusion were included. Demographic, perioperative and postoperative, clinical, and blood type information was recorded. Pre- and post-operative radiographic imaging was analyzed for alignment parameters and development of ASD. RESULTS: 445 patients were included, representing O+ (36.0%), O- (5.2%), A+ (36.2%), A- (6.3%), B+ (12.1%), B- (1.6%), and AB+ (2.7%) blood types. Most patients were female (59.1%), and had a mean age of 60.3 years and BMI of 31.1 kg/m2. Postoperatively, groups did not differ in duration of the hospital (p = 0.732) or intensive care unit (p = 0.830) stay, discharge disposition (p = 0.504), reoperation rate (p = 0.192), or in-hospital complication rate (p = 0.377). Postoperative epidural hematoma was most common amongst A + patients (p = 0.024). Over a mean of 11.0 months of follow-up, all patients exhibited similar improvement in PROMs, with 132 (29.7%) patients developing radiographic evidence of ASD. B + patients were significantly more likely than A + and O + patients to develop spondylolisthesis and ASD (p < 0.05). No significant differences in sagittal alignment parameters and number of levels of fusion were found (p > 0.05). CONCLUSIONS: This is the first large-scale study to address and demonstrate proof-of-principle that ABO blood type, a non-modifiable risk factor, is associated with ASD following lumbar spine fusion.

Gut microbiome dysbiosis is associated with lumbar degenerative spondylolisthesis in symptomatic patients.

Background: Lumbar degenerative spondylolisthesis (LDS), characterized as degeneration of the intervertebral disc and structural changes of the facet joints, is a condition with varying degrees of instability that may lead to pain, canal stenosis, and subsequent surgical intervention. However, the etiology of LDS remains inconclusive. Gut microbiome dysbiosis may stimulate systemic inflammation in various disorders. However, the role of such dysbiosis upon spine health remains under-studied. The current study assessed the association of gut microbiome dysbiosis in symptomatic patients with or without LDS. Methods: A cross-sectional analysis within the framework of a prospective study was performed. DNA was extracted from fecal samples collected from adult symptomatic patients with (n = 21) and without LDS (n = 12). Alpha and beta diversity assessed differences in fecal microbial community between groups. Taxon-by-taxon analysis identified microbial features with differential relative abundance between groups. Subject demographics and imaging parameters were also assessed. Results: There was no significant group differences in age, sex, race, body mass index, smoking/alcohol history, pain profiles, spinopelvic alignment, and Modic changes (p >0.05). LDS subjects had significantly higher disc degeneration severity (p = 0.018) and alpha diversity levels compared to non-LDS subjects (p = 0.002-0.003). Significant differences in gut microbial community structure were observed between groups (p = 0.046). Subjects with LDS exhibited distinct differences at the phylum level, with a significantly higher Firmicutes to Bacteroidota ratio compared to non-LDS (p = 0.003). Differential relative abundance analysis identified six taxa with significant differences between the two groups, with LDS demonstrating an increase in putative pro-inflammatory bacteria (Dialister, CAG-352) and a decrease in anti-inflammatory bacteria (Slackia, Escherichia-Shigella). Conclusion: This study is the first to report a significant association of gut microbiome dysbiosis and LDS in symptomatic patients, noting pro-inflammatory bacterial taxa. This work provides a foundation for future studies addressing the role of the gut microbiome in association with spine health and disease.

Discovery of circulating blood biomarkers in patients with and without Modic changes of the lumbar spine: a preliminary analysis.

PURPOSE: The following study aimed to determine the existence of blood biomarkers in symptomatic patients with or without lumbar Modic changes (MC). METHODS: A cross-sectional sub-analyses of a prospective cohort was performed. Fasting blood samples were collected from patients with and without lumbar MC who had undergone spinal fusion or microdiscectomy. An 80-plex panel and CCL5/RANTES were used to assess preoperative plasma cytokine concentrations. Patient demographics and imaging phenotypes were also assessed. RESULTS: Thirty-one subjects were analysed (n = 18 no MC; n = 13 MC). No significant differences were found in age, sex, body mass index, smoking and alcohol history, and surgical procedure (i.e. fusion, decompression) between the two groups (p > 0.05). Several statistically significant blood biomarkers in MC patients were identified, including elevated levels of C-C Motif Chemokine Ligand 5 (CCL5, p = 0.0006), while Macrophage Migration Inhibitory Factor (MIF) was significantly lower (p = 0.009). Additionally, C-X-C Motif Chemokine Ligand 5 (CXCL5, p = 0.052), Pentraxin 3 (PTX3, p = 0.06) and Galectin-3 (Gal-3, p = 0.07) showed potential relevance. Moreover, MC patients exhibited significantly higher levels of disc degeneration (p = 0.0001) and displacement severity (p = 0.020). Based on multivariate analyses and controlling for disc degeneration/displacement, CCL5 (OR 1.02; 95% CI 1.002-1.033; p = 0.028) and MIF (OR 0.60; 95% CI 0.382-0.951; p = 0.030) were independently associated with MC patients. CONCLUSION: This "proof-of-concept" study is the first to identify specific and significantly circulating blood biomarkers associated with symptomatic patients with lumbar MC, independent of disc alterations of degeneration and/or bulges/herniations. Specifically, differences in CCL5 and MIF protein levels were significantly noted in MC patients compared to those without MC.

Comparison of Daily Versus Admission and Discharge Surveillance Cultures for Multidrug-Resistant Organism Detection in an Intensive Care Unit.

BACKGROUND: Admission and discharge screening of patients for asymptomatic gut colonization with multidrug-resistant organisms (MDROs) is a common approach to active surveillance, but its sensitivity for detecting colonization is uncertain. METHODS: Daily rectal or fecal swab samples and associated clinical data were collected over 12 months from patients in one 25-bed medical intensive care unit (ICU) in Chicago, IL and tested for the following MDROs: vancomycin-resistant enterococci; third-generation cephalosporin-resistant Enterobacterales, including extended-spectrum ß-lactamase-producing Enterobacterales; and carbapenem-resistant Enterobacterales. MDRO detection by (1) admission and discharge surveillance cultures or (2) clinical cultures were compared to daily surveillance cultures. Samples underwent 16S rRNA gene sequencing to measure the relative abundance of operational taxonomic units (OTUs) corresponding to each MDRO. RESULTS: Compared with daily surveillance cultures, admission/discharge cultures detected 91% of prevalent MDRO colonization and 63% of MDRO acquisitions among medical ICU patients. Few (7%) MDRO carriers were identified by clinical cultures alone. Higher relative abundance of MDRO-associated OTUs and specific antibiotic exposures were independently associated with higher probability of MDRO detection by culture. CONCLUSIONS: Admission and discharge surveillance cultures underestimated MDRO acquisitions in an ICU. These limitations should be considered when designing sampling strategies for epidemiologic studies that use culture-based surveillance.

The efficacy and safety of oral antibiotic treatment in patients with chronic low back pain and Modic changes: A systematic review and meta-analysis.

Background: This systematic review and meta-analysis aimed to summarize evidence regarding the effectiveness and safety of oral antibiotic intervention for chronic low back pain (CLBP) patients with/without type-1 Modic changes (MC1). Methods: AMED, CINAHL, Cochrane Library, Embase, and Medline were searched from inception to March 3, 2023. Randomized controlled trials (RCTs) or non-RCTs that investigated the effectiveness or safety of oral antibiotics in treating CLBP patients were eligible for inclusion. Two independent reviewers screened abstracts, full-text articles, and extracted data. The methodological quality of each included article were evaluated by RoB2 and NIH quality assessment tools. The quality of evidence was appraised by GRADE. Meta-analyses were performed, where applicable. A subgroup analysis was conducted to evaluate the RCTs and case series separately, and to evaluate the effect of removing a low-quality RCT. Results: Three RCTs and four case series were included. All Amoxicillin-clavulanate/Amoxicillin treatments lasted for approximately 3 months. Moderate- and low-quality evidence suggested that antibiotic was significantly better than placebo in improving disability and quality of life in CLBP patients with MC1 at 12-month follow-up, respectively. Low-quality evidence from meta-analyses of RCTs showed that oral antibiotic was significantly better than placebo in improving pain and disability in CLBP patients with MC1 immediately post-treatment. Very low-quality evidence from the case series suggested that oral Amoxicillin-clavulanate significantly improved LBP/leg pain, and LBP-related disability. Conversely, low-quality evidence found that oral Amoxicillin alone was not significantly better than placebo in improving global perceived health in patients with CLBP at the 12-month follow-up. Additionally, oral antibiotic users had significantly more adverse effects than placebo users. Conclusions: Although oral antibiotics were statistically superior to placebo in reducing LBP-related disability in patients with CLBP and concomitant MC1, its clinical significance remains uncertain. Future large-scale high-quality RCTs are warranted to validate the effectiveness of antibiotics in individuals with CLBP.

The Human Microbiome and Its Role in Musculoskeletal Disorders.

Musculoskeletal diseases (MSDs) are characterized as injuries and illnesses that affect the musculoskeletal system. MSDs affect every population worldwide and are associated with substantial global burden. Variations in the makeup of the gut microbiota may be related to chronic MSDs. There is growing interest in exploring potential connections between chronic MSDs and variations in the composition of gut microbiota. The human microbiota is a complex community consisting of viruses, archaea, bacteria, and eukaryotes, both inside and outside of the human body. These microorganisms play crucial roles in influencing human physiology, impacting metabolic and immunological systems in health and disease. Different body areas host specific types of microorganisms, with facultative anaerobes dominating the gastrointestinal tract (able to thrive with or without oxygen), while strict aerobes prevail in the nasal cavity, respiratory tract, and skin surfaces (requiring oxygen for development). Together with the immune system, these bacteria have coevolved throughout time, forming complex biological relationships. Changes in the microbial ecology of the gut may have a big impact on health and can help illnesses develop. These changes are frequently impacted by lifestyle choices and underlying medical disorders. The potential for safety, expenses, and efficacy of microbiota-based medicines, even with occasional delivery, has attracted interest. They are, therefore, a desirable candidate for treating MSDs that are chronic and that may have variable progression patterns. As such, the following is a narrative review to address the role of the human microbiome as it relates to MSDs.

Obesity in children with low back pain: implications with imaging phenotypes and opioid use.

BACKGROUND CONTEXT: Low back pain (LBP) is common in children and adolescents, carrying substantial risk for recurrence and continuation into adulthood. Studies have linked obesity to the development of pediatric LBP; however, its association with lumbar spine degeneration, alignment parameters, and opioid use remains debated. PURPOSE: Considering the increasing prevalence of pediatric obesity and LBP and the inherent issues with opioid use, this study aimed to assess the association of obesity with lumbar spine degeneration, spinopelvic alignment, and opioid therapy among pediatric patients. STUDY DESIGN/SETTING: A retrospective study of pediatric patients presenting to a single institute with LBP and no history of spine deformity, tumor, or infection was performed. PATIENT SAMPLE: A totasl of 194 patients (mean age: 16.7±2.3 years, 45.3% male) were included, of which 30 (15.5%) were obese. OUTCOME MEASURES: Prevalence of imaging phenotypes and opioid use among obese to nonobese pediatric LBP patients. Magnetic resonance and plain radiographic imaging were evaluated for degenerative phenotypes (disc bulging, disc herniation, disc degeneration [DD], high-intensity zones [HIZ], disc narrowing, Schmorl's nodes, endplate phenotypes, Modic changes, spondylolisthesis, and osteophytes). Lumbopelvic parameters including lumbar lordosis, pelvic tilt, sacral slope, pelvic incidence and pelvic incidence-lumbar lordosis (PI-LL) mismatch were also examined. METHODS: Demographic and clinical information was recorded, including use of opioids. The associations between obesity and lumbar phenotypes or opiod use were assessed by multiple regression models. RESULTS: Based on multivariate analysis, obesity was significantly associated with the presence of HIZ (adjusted OR: 5.36, 95% CI: 1.30 to 22.09). Further analysis demonstrated obesity (adjusted OR: 3.92, 95% CI: 1.49 to 10.34) and disc herniation (OR: 4.10, 95% CI: 1.50 to 11.26) were associated with opioid use, independent of duration of symptoms, other potential demographic determinants, and spinopelvic alignment. CONCLUSIONS: In pediatric patients, obesity was found to be significantly associated with HIZs of the lumbar spine, while disc herniation and obesity were associated with opioid use. Spinopelvic alignment parameters did not mitigate any outcome. This study underscores that pediatric obesity increases the risk of developing specific degenerative spine changes and pain severity that may necessitate opioid use, emphasizing the importance of maintaining healthy body weight in promoting lumbar spine health in the young.

Prediction of lumbar disc herniation resorption in symptomatic patients: a prospective, multi-imaging and clinical phenotype study.

BACKGROUND CONTEXT: Symptomatic lumbar disc herniations (LDH) are very common. LDH resorption may occur by a "self-healing" process, however this phenomenon remains poorly understood. By most guidelines, if LDH remains symptomatic after 3 months and conservative management fails, surgical intervention may be an option. PURPOSE: The following prospective study aimed to identify determinants that may predict early versus late LDH resorption. STUDY DESIGN/SETTING: Prospective study with patients recruited at a single center. PATIENT SAMPLE: Ninety-three consecutive patients diagnosed with acute symptomatic LDH were included in this study (n=23 early resorption and n=67 late resorption groups) with a mean age of 48.7±11.9 years. OUTCOMES MEASURE: Baseline assessment of patient demographics (eg, smoking status, height, weight, etc.), herniation characteristics (eg, the initial level of herniation, the direction of herniation, prevalence of multiple herniations, etc.) and MRI phenotypes (eg, Modic changes, end plate abnormalities, disc degeneration, vertebral body dimensions, etc.) were collected for further analysis. Lumbar MRIs were performed approximately every 3 months for 1 year from time of enrollment to assess disc integrity. METHODS: All patients were managed similarly. LDH resorption was classified as early (<3 months) or late (>3 months). A prediction model of pretreatment factors was constructed. RESULTS: No significant differences were noted between groups at any time-point (p>.05). Patients in the early resorption group experienced greater percent reduction of disc herniation between MRI-0-MRI-1 (p=.043), reduction of herniation size for total study duration (p=.007), and percent resorption per day compared to the late resorption group (p<.001). Based on multivariate modeling, greater L4 posterior vertebral height (coeff:14.58), greater sacral slope (coeff:0.12), and greater herniated volume (coeff:0.013) at baseline were found to be most predictive of early resorption (p<.05). CONCLUSIONS: This is the first comprehensive imaging and clinical phenotypic prospective study, to our knowledge, that has identified distinct determinants for early LDH resorption. Early resorption can occur in 24.7% of LDH patients. We developed a prediction model for early resorption which demonstrated great overall performance according to pretreatment measures of herniation size, L4 posterior body height, and sacral slope. A risk profile is proposed which may aid clinical decision-making and managing patient expectations.

ISSLS PRIZE in Clinical Science 2022: Epidemiology, risk factors and clinical impact of juvenile Modic changes in paediatric patients with low back pain.

PURPOSE: It's a long-held belief that Modic changes (MC) occur only in adults, with advanced age, and are highly associated with pain and adverse outcomes. The following study addressed the epidemiology, risk factors and clinical relevance of MC in young paediatric patients. METHODS: Two hundred and seven consecutive patients with no history of deformities, neoplasms, trauma, or infections were included in this ambispective study. MRIs were utilized to assess MCs and types, and other degenerative disc/endplate abnormalities. Subject demographics, duration of symptoms, clinic visits, conservative management (physical therapy, NSAIDs, opioids, injections) and surgery were noted. RESULTS: The mean age was 16.5 years old (46.9% males), 14% had MCs and they occurred throughout the spine. Subject baseline demographics were similar between MCs and non-MCs patients (p > 0.05). Modic type 2 (50%) was the most common type (type 1:27.1%; type 3:18.8%; mixed:4.7%). Multivariate analyses noted that endplate damage (OR: 11.36), disc degeneration (OR: 5.81), disc space narrowing (OR: 5.77), Schmorl's nodes (OR: 4.30) and spondylolisthesis (OR: 3.55) to be significantly associated with MCs (p < 0.05). No significant differences in conservative management were noted between Modic and non-MCs patients (p > 0.05). Among surgery patients (n = 44), 21% also had MCs (p = 0.134). Symptom-duration was significantly greater in MC patients (p = 0.049). CONCLUSION: Contrary to traditional dogma, robust evidence now exists noting that MCs and their types can develop in children. Our findings give credence to the "Juvenile" variant of MCs, whereby its implications throughout the lifespan need to be assessed. Juvenile MCs have prolonged symptoms and related to specific structural spine phenotypes.

A Comparison of Surgical Outcomes Between Minimally Invasive and Open Thoracolumbar Corpectomy.

BACKGROUND: Minimally invasive (MIS) techniques have gained considerable attention for the management of degenerative spinal pathologies. However, few studies have compared the outcomes between MIS and open thoracolumbar corpectomies. The purpose of this study was to compare perioperative variables between MIS and open thoracolumbar corpectomy. METHODS: Retrospective review of 33 patients who underwent either an MIS or open thoracolumbar corpectomy by a single surgeon between 2005 and 2012 was performed. Patients were separated into anterior-posterior MIS (MIS AP), anterior-posterior open (AP), and posterior open (P) cohorts. Postoperative narcotic use was converted to oral morphine equivalents (OMEs). Demographics, comorbidity, perioperative variables, complications, and computed tomographic analyses were assessed. Fisher exact test was performed for categorical variables and Student t test for continuous variables. A P value of ≤ .05 denoted statistical significance. RESULTS: Thirty-three patients underwent an MIS AP, AP, or P thoracolumbar corpectomy (39.4% vs 15.2% vs 45.5%, respectively). MIS AP patients were younger with a lower comorbidity burden than either open cohorts. In addition, MIS AP patients demonstrated a decreased procedural time, lower blood loss, and shorter hospitalization than either open cohorts. MIS AP patients required less units of transfusion than P and AP patients while demonstrating lower postoperative narcotics consumption and reoperations rates than open AP patients. Surgical site infection rates, body mass index, intraoperative fluid requirements, and complication rates were similar between cohorts. All patients demonstrated successful arthrodesis at 1 year based upon computed tomography. CONCLUSIONS: MIS AP thoracolumbar corpectomy patients incurred decreased procedural times, shorter hospitalization, and lower blood loss compared with open patients. MIS AP patients demonstrated decreased postoperative narcotics consumption and reoperation rates compared with traditional AP patients. All patients demonstrated successful arthrodesis. CLINICAL RELEVANCE: The MIS approach to thoracolumbar corpectomies appears to be a safe and efficacious alternative when compared with traditional methods.

Comparison of Surgical Outcomes, Narcotics Utilization, and Costs After an Anterior Cervical Discectomy and Fusion: Stand-alone Cage Versus Anterior Plating.

STUDY DESIGN: Retrospective cohort analysis of a prospectively maintained registry. OBJECTIVE: To compare the surgical outcomes, narcotic utilization, and costs between a stand-alone (SA) cage and anterior plating (AP) with an interbody device for 1-level anterior cervical discectomy and fusion (ACDF). BACKGROUND DATA: ACDF with a SA cage has gained popularity as a potential alternative to anterior cervical plating. Few studies have compared the surgical outcomes, narcotic utilization, and costs of ACDF utilizing a SA cage versus AP with an interbody device. METHODS: Patients who underwent a primary 1-level ACDF for degenerative spinal pathology between 2010 and 2013 were analyzed. Patients were stratified on the basis of the type of implant system (SA cage vs. AP) and assessed with regard to demographics, comorbidities, smoking, visual analogue scale (VAS) scores (preoperative/postoperative), procedural time, estimated blood loss (EBL), length of hospitalization, complications, reoperations, narcotic consumption, and total costs. Statistical analysis was performed with independent sample T tests for continuous variables and χ analysis for categorical data. An α level of <0.05 denoted statistical significance. RESULTS: Of the 93 patients included, 52 (55.9%) underwent an ACDF with a SA cage system. Patient demographics, comorbidity burden, body mass index, smoking status, and preoperative VAS score were similar between cohorts. The SA cohort incurred a significantly lower EBL (P<0.001) than the AP cohort. However, none required a transfusion and the procedural time, length of hospitalization, postoperative VAS score, complication rates, 1-year arthrodesis rate, and reoperation rates were similar between cohorts. Postoperative narcotics consumption and total costs were also similar between groups. CONCLUSIONS: Our findings suggest that the SA cage may be associated with a significantly lower EBL, which may not be clinically relevant. Perioperative outcomes, complications, reoperation rates, narcotics consumption in the immediate postoperative period, and total costs may be similar regardless of the instrumentation utilized in a 1-level ACDF.

Neuroforaminal Bone Growth Following Minimally Invasive Transforaminal Lumbar Interbody Fusion With BMP: A Computed Tomographic Analysis.

STUDY DESIGN: Computed tomographic analysis. OBJECTIVE: To identify radiographic patterns of symptomatic neuroforaminal bone growth (NFB) in patients who have undergone a single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) augmented with bone morphogenetic proteins (BMP) utilizing computed tomography (CT). SUMMARY OF BACKGROUND DATA: BMP induces osteoblast differentiation leading to new bone formation. The association of BMP utilization and heterotopic bone formation after an MIS-TLIF has been described. However, studies have been limited in their patient population and details regarding diagnosis and treatment of NFB. MATERIALS AND METHODS: Postoperative CT scans of the symptomatic and asymptomatic patients were analyzed to identify patterns of heterotopic bone growth on axial and sagittal views. The area of bone growth at the disk level, lateral recess, adjacent foramen, and retrovertebral area were measured. Mann-Whitney U test was used to compare the areas of bone growth between cohorts. RESULTS: Postoperative CT images between 18 symptomatic and 13 asymptomatic patients were compared. On axial views, the symptomatic patients demonstrated greater areas of bone growth at the disk level (164.0±92.4 vs. 77.0±104.9 mm), and lateral recess (69.6±70.5 and 5.9±12.5 mm) as well as in the total cross-sectional area (290.3±162.1 vs. 119.4±115.6 mm). On sagittal imaging, the mean bone growth at the subarticular level (148.7±185.1 vs. 35.8±37.4 mm) and the total cross-sectional area (298.4±324.4 vs. 85.8±76.3 mm) were greater in symptomatic patients (P<0.01). Amount of BMP utilized and operative levels were no different between cohorts. CONCLUSIONS: The findings of the present study suggest that an anatomic association exists between recalcitrant postoperative radiculopathy and NFB following an MIS-TLIF with BMP. Increased total bone growth as measured on serial axial and sagittal sections was associated with postoperative radiculopathy. The association between radiculopathy and the extension of BMP-induced bone growth toward the traversing nerve root appeared the most significant.

The Utility of Routinely Obtaining Postoperative Laboratory Studies Following a Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: This is a retrospective analysis. OBJECTIVE: To test the hypothesis that there is limited utility in routinely obtaining postoperative laboratory values following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). BACKGROUND DATA: At many institutions, it is routine to obtain a complete blood count and basic metabolic profile (BMP) following a MIS TLIF. However, the utility of this practice has not been well characterized. METHODS: A total of 332 consecutive patients who underwent a primary, 1-level MIS TLIF for degenerative spinal pathology between 2007 and 2013 were identified. Patients were stratified into low-risk and high-risk cohorts based upon risk for postoperative laboratory abnormalities. Inclusion criteria for the high-risk cohort were malignancy, complicated diabetes, renal failure, liver disease, hematologic disease, or significant intraoperative blood loss (>300 mL). Preoperative and postoperative hemoglobin (Hb), hematocrit, and BMP values were compared. Any interventions that were potentially related to laboratory values were identified. RESULTS: Totals of 270 low-risk and 62 high-risk patients were identified. Mean postoperative Hb, hematocrit, blood urea nitrogen, sodium, potassium, and calcium values were decreased compared with preoperative values (P<0.001 for each) in both cohorts. Similar changes from preoperative levels were demonstrated in each cohort. No patients received blood product transfusion. Eleven low-risk (4.1%) and 5 high-risk patients (8.1%) received oral potassium supplementation. All patients who received potassium supplementation were asymptomatic. Most patients who were given potassium replacement consumed medications known to decrease serum potassium levels. No other interventions were performed in either group. CONCLUSIONS: Despite a significant decrease in mean Hb concentration following surgery, no patients required a transfusion. In total, 16 patients received potassium supplementation likely related to medication-related potassium deficits. Overall, these findings suggest that the utility of routinely obtaining a complete blood count or BMP following uncomplicated MIS TLIF may be limited except in the setting of select preoperative comorbidities and/or perioperative risk factors or events. LEVEL OF EVIDENCE: Level III.

Functional Capacity Evaluation Following Spinal Fusion Surgery.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: The aim of the study was to characterize outcomes of functional capacity evaluations (FCEs) amongst patients undergoing spinal fusion surgery. SUMMARY OF BACKGROUND DATA: Injured workers often undergo an FCE upon reaching maximal medical improvement following surgery. To date, few studies have examined the results of FCEs following spinal fusion. METHODS: Patients undergoing an FCE following a minimally invasive transforaminal lumbar interbody fusion (TLIF) or anterior cervical discectomy and fusion (ACDF) were retrospectively identified. Based upon the FCE report, each patient's job-related preoperative physical requirement and postoperative work capability was categorized as light, medium, or heavy. Patients were characterized as being able to meet their preoperative job requirement if their FCE-determined capability was greater than or equal to their preoperative job requirement. Patient characteristics were tested for association with meeting preoperative job requirement using bivariate and multivariate regression. RESULTS: A total of 173 patients were identified: 71 (41.0%) and 102 (59.0%) underwent TLIF and ACDF, respectively. Of the 71 TLIF and 102 ACDF patients, 41 (58%) and 50 (49%) had light postoperative capabilities, 18 (25%) and 38 (37%) as medium, and 12 (17%) and 14 (14%) as heavy, respectively. Postoperatively, 26 (37%) of TLIF and 55 (54%) of ACDF patients were categorized as meeting their preoperative job requirement. Independent predictors of meeting preoperative job requirement following TLIF (P =0.002) and ACDF (P = 0.037) were lower preoperative job requirement, and younger age for ACDF (P < 0.001). CONCLUSION: Only one in five patients undergoing spinal fusion surgery for occupational injuries is able to perform heavy-duty work postoperatively. Similarly, approximately half of patients are able to perform medium-duty work. Moreover, a majority of patients are unable to return to their preoperative occupational responsibilities. These findings can be used to council patients regarding their likelihood of meeting postoperative work capacity. LEVEL OF EVIDENCE: 3.

Preoperative narcotic utilization: accuracy of patient self-reporting and its association with postoperative narcotic consumption.

OBJECTIVE: Little is known about the accuracy of reporting of preoperative narcotic utilization in spinal surgery. As such, the purpose of this study is to compare postoperative narcotic consumption between preoperative narcotic utilizers who do and do not accurately self-report preoperative utilization. METHODS: Patients who underwent anterior cervical discectomy and fusion, minimally invasive lumbar discectomy, or minimally invasive transforaminal lumbar interbody fusion procedures between 2013 and 2014 were prospectively identified. The accuracy of self-reporting preoperative narcotic consumption was determined utilizing the Illinois Prescription Monitoring Program. Total inpatient narcotic consumption during postoperative Days 0 and 1 was compared according to the demographics and preoperative narcotic reporting accuracy. Similarly, the proportion of patients who continued to be dependent on narcotic medications at each postoperative visit was compared according to the demographics and preoperative narcotic reporting accuracy. RESULTS: A total of 195 patients met the inclusion criteria. Of these, 25% did not use narcotics preoperatively, while 47% and 28% did do so with accurate and inaccurate reporting, respectively. Patients who used narcotics preoperatively were more likely to demonstrate elevated inpatient narcotic consumption (adjusted RR 5.3; 95% CI 1.4-20.1; p = 0.013). However, such patients were no more or less likely to be dependent on narcotic medications at the first (p = 0.618) or second (p = 0.798) postoperative visit. Among patients who used narcotics preoperatively, no differences were demonstrated in terms of inpatient narcotic consumption (p = 0.182) or narcotic dependence following the first (p = 0.982) or second (p = 0.866) postoperative visit according to the self-reported accuracy of preoperative narcotic utilization. The only preoperative factors that were independently associated with elevated inpatient narcotic consumption were workers' compensation status and procedure type. The only preoperative factors that were independently associated with narcotic dependence at the first postoperative visit were female sex, workers' compensation status, and procedure type. The only preoperative factor that was independently associated with narcotic dependence at the second postoperative visit was procedure type. CONCLUSIONS: The findings suggest that determining the actual preoperative narcotic utilization in patients who undergo spine surgery may help optimize postoperative pain management. Approximately 75% of patients used narcotics preoperatively. Patients who used narcotics preoperatively demonstrated significantly higher inpatient narcotic consumption, but this difference did not persist following discharge. Finally, postoperative narcotic consumption (inpatient and following discharge) was independent of the self-reported accuracy of preoperative narcotic utilization. Taken together, these findings suggest that corroboration between the patient's self-reported preoperative narcotic utilization and other sources of information (e.g., family members and narcotic registries) may be clinically valuable with respect to minimizing narcotic requirements, thereby potentially improving the management of postoperative pain.

The Impact of Worker's Compensation Claims on Outcomes and Costs Following an Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective matched pair cohort analysis using a prospectively maintained registry. OBJECTIVE: To describe the findings associated with workers' compensation (WC) claimants in regard to surgical outcomes, costs, and reimbursement after a 1- or 2- level anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: WC patients are perceived to demonstrate poor surgical outcomes and greater health care expenditure than more traditional patients. This study aims to evaluate the perceived differences in financial costs between patients with and without WC insurance. METHODS: A retrospective analysis of 352 patients who underwent a primary 1- or 2- level anterior cervical discectomy and fusion for degenerative spinal etiologies between 2007 and 2013 by a single surgeon was performed. Patients were stratified on the basis of the payer status (WC vs. non-WC). Demographics, Charlson Comorbidity Index scores, smoking status, pre- and postoperative Visual Analogue Scale (VAS) scores, procedural time, estimated blood loss, hospital length of stay, complications, and revisions/reoperations were assessed between cohorts. The 1-year arthrodesis rate was also evaluated via computed tomography. Two cohorts of 30 patients were then matched for the number of fusion levels, smoking, and Charlson Comorbidity Index scores to compare hospital costs and reimbursements. All financial data were reported as a ratio of non-WC to WC payment/charges to protect hospital-sensitive financial data. Statistical analysis was performed using the independent sample t test for continuous variables and χ analysis for categorical data. An α level of less than 0.05 denoted statistical significance. RESULTS: A total of 352 patients were included in this study of which 132 (37.5%) carried WC as the primary payer. The WC cohort was significantly younger (45.2 ± 8.5 vs. 52.9 ± 11.9, P < 0.001) and demonstrated a reduced comorbidity burden (2.3 ± 1.2 vs. 3.4 ± 1.7, P < 0.001) compared with non-WC patients. In addition, the WC cohort consisted of a significantly greater proportion of males, non-Caucasians, and active tobacco users. The preoperative VAS score, number of fusion levels, procedural time, and hospital length of stay did not significantly vary between cohorts. The 6-month VAS scores (3.2 ± 2.9 vs. 2.3 ± 2.4, P < 0.05), pseudarthrosis rates (7.6% vs. 0.9%, P < 0.001), revision/reoperations (12.9% vs. 2.7%, P < 0.001), and smoking rates (29.8% vs. 20.5%, P < 0.05) were significantly increased among WC payers. The difference in the total charges for anterior cervical discectomy and fusion between the WC cohort and the non-WC cohort was not statistically significant. The costs associated with implants, anesthesia, operating room, and in-hospital therapy were comparable between cohorts. The WC cohort was associated with a 282% higher reimbursement rate than the non-WC cohort (P < 0.001). CONCLUSION: The WC cohort demonstrated lower clinical improvement, reduced 1-year arthrodesis rate, and an increased incidence of revision/reoperations when compared with non-WC patients. The greater proportion of smokers and increased occupational demands within the WC cohort may help explain these findings. Reimbursement rates were significantly higher in the WC patients. However, costs to the health care system during the acute hospitalization period (implants, operating room resources, postoperative care, and therapy) were similar between cohorts. LEVEL OF EVIDENCE: 3.

Postoperative Narcotic Consumption in Workman's Compensation Patients Following a Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective cohort analysis of a prospective registry. OBJECTIVE: To assess the differences in perioperative narcotic consumption between Workman's compensation (WC) and non-Workman's compensation (non-WC) patients after a single-level minimally invasive transforaminal lumbar interbody fusion. SUMMARY OF BACKGROUND DATA: There is concern regarding the potential overutilization of opioid pain medication in WC patients. However, the impact of WC status on perioperative narcotic consumption after lumbar spine procedures has not been previously reported. METHODS: A cohort of patients who underwent primary 1-level minimally invasive transforaminal lumbar interbody fusion procedures for degenerative spinal pathology between 2007 and 2013 was retrospectively analyzed using a prospectively collected registry. First, preoperative and perioperative characteristics were compared between WC and non-WC patients. Second, mean oral morphine equivalent was compared between WC and non-WC patients with adjustment for any preoperative or perioperative differences between cohorts. RESULTS: A total of 136 single-level, primary minimally invasive-transforaminal lumbar interbody fusion procedures were included in the analysis, of which 46 (33.8%) were WC patients. WC patients were younger (47.8 ± 11.2 vs. 57.9 ± 10.4 yr; P < 0.001) and had a lower comorbidity burden (Charlson Comorbidity Index: 1.85 ± 1.30 vs. 3.42 ± 2.07; P < 0.001) than non-WC patients. The distribution of ethnicity differed between WC and non-WC patients (P = 0.002). WC patients incurred longer procedural times (135.2 ± 52.2 vs. 118.9 ± 33.7 min; P < 0.05). However, the estimated blood loss, length of hospital stay, and day of discharge were no different between WC and non-WC patients. Mean oral morphine equivalent consumption did not differ between WC and non-WC patients after adjustment for differences in age, ethnicity, Charlson Comorbidity Index, and procedural time between cohorts. CONCLUSION: Despite concerns for greater opioid use in the WC population, this analysis demonstrated similar total narcotic consumption between WC and non-WC patients during the immediate postoperative period. Long-term studies are warranted to assess whether this similarity in regard to perioperative narcotic consumption persists beyond the immediate postoperative period. LEVEL OF EVIDENCE: 3.

Primary Versus Revision Single-level Minimally Invasive Lumbar Discectomy: Analysis of Clinical Outcomes and Narcotic Utilization.

STUDY DESIGN: Retrospective cohort analysis of a prospectively maintained registry. OBJECTIVE: To compare the intraoperative variables, surgical outcomes, and narcotic utilization between primary and revision 1-level minimally invasive (MIS) lumbar discectomies. SUMMARY OF BACKGROUND DATA: Revision spine surgery may be associated with longer procedural time and greater soft tissue disruption. Few studies have analyzed the surgical outcomes and narcotic utilization associated with MIS revision lumbar discectomies. METHODS: A retrospective analysis of 227 consecutive cases of MIS 1-level lumbar discectomy for degenerative spinal pathology between 2009 and 2014 by a single surgeon was performed. Patients were stratified into primary and revision cohorts. Demographics, comorbidity, intraoperative parameters, peri- and postoperative outcomes, and reoperations were assessed. Postoperative narcotic utilization was compared between cohorts. Statistical analyses were performed using Student t-test and Pearson χ test. A P < 0.05 denoted statistical significance. RESULTS: Of the 227 cases included, 186 patients (81.9%) and 41 patients (18.1%) were included in the primary and revision cohorts, respectively. Demographics, comorbidity, smoking status, preoperative visual analogue scale (VAS) scores, and estimated blood loss did not differ between cohorts. However, the revision cohort demonstrated a longer procedural time, increased length of hospitalization, and higher postoperative narcotic utilization. Although not statistically significant, revision patients trended toward higher 6-week postoperative VAS scores and reherniation rates. In addition, revision patients were more likely to undergo subsequent lumbar fusion than primary patients. CONCLUSION: The findings suggest that revision MIS lumbar discectomy may be associated with increased procedural time, increased length of hospitalization, and increased postoperative narcotic utilization. Whereas revision patients trended toward higher postoperative VAS scores at 6 weeks, both cohorts demonstrated similar pain levels at final follow-up. Finally, revision patients may be at a greater risk of reherniation and subsequent reoperation. Further studies are warranted to characterize the independent risk factors for a revision lumbar discectomy. LEVEL OF EVIDENCE: 3.