PROMIS Physical Function Score Strongly Correlates With Legacy Outcome Measures in Minimally Invasive Lumbar Microdiscectomy.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: This study aims to determine the validity of the patient-reported outcomes measurement information system (PROMIS) physical function (PF) in minimally invasive lumbar discectomy (MIS LD) patients. SUMMARY OF BACKGROUND DATA: PROMIS was designed to allow for assessment of clinical outcomes in fewer questions than previous outcome measures with the goal of reducing noncompliance associated with longer, time-consuming surveys. However, there exists a paucity of evidence regarding the efficacy of the PROMIS PF domain in patients undergoing MIS LD. METHODS: A surgical database of patients undergoing 1-3 level MIS LD was retrospectively reviewed. Postoperative changes in PROMIS PF scores were analyzed at 6-weeks, 12-weeks, and 6-months using paired Student t tests. PROMIS scores were compared to Oswestry disability index (ODI), visual analog scale (VAS) back, and VAS leg scores. Correlations were tested using Pearson correlation coefficient. RESULTS: Forty-one MIS LD patients were identified, reporting an average preoperative PROMIS PF score of 35.36 ±â€Š7. Patients demonstrated significant improvement in ODI, VAS back, and VAS leg scores. Additionally, strong associations with PROMIS scores were observed for preoperative and postoperative ODI (r range: 0.5735-0.8543) and postoperative VAS back (r range: 0.5332-0.6522) and VAS leg pain (r range: 0.5257-0.6412). CONCLUSION: Patients undergoing MIS LD demonstrated significant improvements in PROMIS PF, ODI, VAS back, and VAS leg pain postoperatively. Additionally, improvements in PROMIS physical function scores at each postoperative time point were determined to be significantly correlated with ODI, VAS back, and VAS leg pain. The results of the current study demonstrate PROMIS PF has strong utility as a postoperative outcome assessment tool. LEVEL OF EVIDENCE: 4.

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.

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.

Mesenchymal stem cell allograft as a fusion adjunct in one- and two-level anterior cervical discectomy and fusion: a matched cohort analysis.

BACKGROUND CONTEXT: Live mesenchymal stem cell (MSC) allograft-containing allogeneic bone grafts have recently gained popularity and currently account for greater than 17% of all bone grafts and bone graft substitutes used in spinal surgery. Although the claim of cellular bone matrices containing osteogenic cells with osteoinductive properties is attractive, little is known about their clinical success when used in anterior cervical discectomy and fusion (ACDF). PURPOSE: The objective of this study was to report on the radiographic fusion rates in one- and two-level instrumented ACDF using an MSC. STUDY DESIGN/SETTING: This was a retrospective review of prospectively matched cohort of patients with radiologic assessment of fusion as the primary end point. PATIENT SAMPLE: Two matched cohorts of adult patients who underwent ACDF with MSC or standard allograft were included. OUTCOMES MEASURES: The outcome measures included radiographic and clinical evidence of healing at 1 year. METHODS: A consecutive series of 57 patients who underwent a one- or two-level instrumented ACDF procedure between 2010 and 2012 were retrospectively analyzed. All fusion constructs comprised an interbody allograft, an anterior plate, and Osteocel (NuVasive, San Diego, CA, USA). These patients were matched to a control group of 57 patients. RESULTS: Of the 57 cases in both cohorts, 29 (50.9%) were single-level, and 28 (49.1%) were two-level instrumented ACDFs. There were no significant differences in patient age (p=.71), gender, comorbidity burden (Charlson Comorbidity Index [CCI]: 1.95; 2.42, p=.71) or body mass index (p=.79). At the 1-year follow-up, 50 of 57 (87.7%) patients in the Osteocel cohort demonstrated a solid fusion compared with 54 of 57 (94.7%) in the control group (p=.19). Seven (12.3%) patients in the Osteocel cohort were reported as having a failed fusion at 1 year. CONCLUSIONS: This is the first non-industry sponsored study to analyze a matched cohort assessing the 1-year arthrodesis rates associated with a nonstructural MSC allograft in one- and two-level ACDF procedures. Although not statistically significant, patients treated with MSC allografts demonstrated lower fusion rates compared with a matched non-MSC cohort.

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.

The utility of obtaining routine hematological laboratory values following an anterior cervical diskectomy and fusion.

STUDY DESIGN: Retrospective analysis of a prospectively maintained database. OBJECTIVE: To characterize the utility of obtaining routine postoperative laboratory studies after an anterior cervical diskectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: ACDF is typically associated with minimal blood loss and morbidity. However, at many institutions, postoperative laboratory studies are conducted routinely. This study aims to characterize the utility of these tests in the postoperative setting. METHODS: A retrospective analysis of a prospectively maintained database of 332 patients who underwent an ACDF for degenerative cervical spine disease between 2007 and 2014 was performed. Patients with a concurrent corpectomy, posterior fusion, or revision procedure were excluded. Patient demographics, comorbidities, visual analogue scale scores, surgical and hospitalization parameters, complications, and transfusion volumes were assessed. The patient's postoperative laboratory studies were compared with preoperative values. Statistical analysis was performed with independent sample T tests for continuous variables and χ analysis for categorical data. An α level of less than 0.05 denoted statistical significance. RESULTS: A total of 332 patients were included with a mean age of 51.1 ± 11.7 years. The overall mean procedural time, estimated blood loss, and length of stay were 60.0 ± 30.1 minutes, 69.4 ± 36.2 mL, and 40.2 ± 20.3 hours, respectively. Overall, 98.1% of patients demonstrated radiographical arthrodesis at 1 year. After a 1- or 2-level ACDF, the postoperative hemoglobin, hematocrit, blood urea nitrogen, sodium, and calcium levels significantly decreased, whereas glucose and chloride levels increased when compared with the preoperative values (P < 0.05). In addition, the 1-level ACDF cohort was also associated with reduced postoperative potassium level (P < 0.05). However, none of the patients required intraoperative or postoperative blood product transfusion or demonstrated evidence of postoperative anemia. Two patients (0.89%) required postoperative potassium replacement based upon laboratory values alone without clinical symptomatology. There were no complications that were related to the patient's hemodynamic status or fluid and electrolyte balance. CONCLUSION: In the majority of cases after an ACDF, no action was taken n the basis of the patient's routine postoperative laboratory data. None of the patients required blood product transfusion, whereas only 0.89% (n = 2) required potassium replacement for laboratory anomalies without clinical symptomatology. These findings suggest that routine postoperative complete blood counts do not change postoperative management after an ACDF unless intraoperative bleeding is noted or the patient carries risk factors for postoperative hemorrhagic anemia. LEVEL OF EVIDENCE: 3.

Cost analysis of incidental durotomy in spine surgery.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: To characterize the consequences of an incidental durotomy with regard to perioperative complications and total hospital costs. SUMMARY OF BACKGROUND DATA: There is a paucity of data regarding how an incidental durotomy and its associated complications may relate to total hospital costs. METHODS: The Nationwide Inpatient Sample database was queried from 2008 to 2011. Patients who underwent cervical or lumbar decompression and/or fusion procedures were identified, stratified by approach, and separated into cohorts based on a documented intraoperative incidental durotomy. Patient demographics, comorbidities (Charlson Comorbidity Index), length of hospital stay, perioperative outcomes, and costs were assessed. Analysis of covariance and multivariate linear regression were used to assess the adjusted mean costs of hospitalization as a function of durotomy. RESULTS: The incidental durotomy rate in cervical and lumbar spine surgery is 0.4% and 2.9%, respectively. Patients with an incidental durotomy incurred a longer hospitalization and a greater incidence of perioperative complications including hematoma and neurological injury (P < 0.001). Regression analysis demonstrated that a cervical durotomy and its postoperative sequelae contributed an additional adjusted $7638 (95% confidence interval, 6489-8787; P < 0.001) to the total hospital costs. Similarly, lumbar durotomy contributed an additional adjusted $2412 (95% confidence interval, 1920-2902; P < 0.001) to the total hospital costs. The approach-specific procedural groups demonstrated similar discrepancies in the mean total hospital costs as a function of durotomy. CONCLUSION: This analysis of the Nationwide Inpatient Sample database demonstrates that incidental durotomies increase hospital resource utilization and costs. In addition, it seems that a cervical durotomy and its associated complications carry a greater financial burden than a lumbar durotomy. Further studies are warranted to investigate the long-term financial implications of incidental durotomies in spine surgery and to reduce the costs associated with this complication. LEVEL OF EVIDENCE: 3.