Faculty Bibliography

INTRODUCTION/BACKGROUND:Balance and fall risk before and after lumbar surgery was assessed to determine whether balance at baseline predicts long-term postsurgical outcomes. METHODS:Forty-three patients in the United States and Israel performed the single-leg stance (SLS) test, four square step test (FSST), and 8-foot up-and-go (8FUG) test before and 2 to 4 months after lumbar spine surgery. They completed the Oswestry Disability Index (ODI) and pain rating before and 12 months after lumbar surgery. RESULTS:From baseline to follow-up, the SLS time was 3.74 seconds longer (P = 0.01), the FSST time was 1.94 seconds faster (P < 0.001), and the 8FUG time was 1.55 seconds faster (P = 0.02). Before surgery, 26% of the patients were considered high fall risk according to the FSST and 51% according to the 8FUG. Postsurgery, all patients could complete the physical tests, but 26% remained at high fall risk according to the 8FUG and 7.5% according to the FSST. The three physical measures together explained 30% of the variance in postsurgical ODI scores (P = 0.02). Age was not correlated with performance. DISCUSSION/CONCLUSIONS:Risk of falling is higher than surgeons suspect. Balance tests (ie, SLS, FSST, and 8FUG) are quick and easy to administer. The findings support the importance of screening for balance and fall risk in adults undergoing lumbar spine surgery.

INTRODUCTION/BACKGROUND:Patient reported outcomes measurement information system (PROMIS) is a quality of life metric that has gained increased popularity due to computer adaptive testing. Previous studies have shown that PROMIS correlates with Oswestry Disability Index (ODI) in patients with back pain and takes significantly less time to complete. However, the ability of PROMIS to capture disability from spinal malalignment relative to established metrics is unknown. The aim of the present study is to validate the correlation between ODI and PROMIS in patients with back pain, analyze correlations of PROMIS and legacy metrics to sagittal alignment, and identify major drivers of PROMIS scores and ODI in patients with back pain. METHODS:A retrospective review was conducted of a prospectively collected outcome measures database (PROMIS, ODI, VAS Back, VAS Leg, VAS Neck, and VAS Arm) of spine patients > 18 years. Inclusion criteria for the present study was a chief complaint of back pain and full length weight bearing X-rays within 30 days of health related quality of life (HRQL) completion. Demographic information, radiographic alignment, psychiatric diagnoses, and comorbidities were recorded. PROMIS metrics were correlated to legacy metrics (ODI and VAS). Next, outcome metrics were correlated with sagittal alignment variables T1 Pelvic Angle (TPA), SVA, PT, and PI-LL. Patients were grouped based on the presence of spinal deformity (defined radiographically as any one of SVA > 4 cm, PI-LL > 10°, PT > 20°) and mean HRQL scores were investigated for the adult spinal deformity (ASD) and non-ASD groups. Finally, drivers of PROMIS PF scores and ODI scores were determined using multiple stepwise regression. RESULTS: = 0.376, p < 0.001). CONCLUSIONS:In a cohort of 150 patients with back pain, PROMIS correlated strongly with legacy outcome metrics, including VAS and ODI. PROMIS PF correlated more strongly with sagittal malalignment than ODI. Additionally, patients with spinal deformity had significantly worse PROMIS PF scores but similar ODI scores as patients without ASD. Finally, sagittal alignment was found to be a significant driver of PROMIS PF scores but not ODI scores. PROMIS PF should be utilized as a disability assessment tool in patients with spinal deformity due to ease of use, strong correlations with legacy metrics, and ability to capture disability resulting from sagittal alignment.

PURPOSE/OBJECTIVE:Predictors of long-term opioid usage in TLIF patients have not been previously explored in the literature. We examined the effect of pre-operative narcotic use in addition to other predictors of the pattern and duration of post-operative narcotic usage. METHODS:We conducted a retrospective cohort study at a single academic institution of patients undergoing a one- or two-level primary TLIF between 2014 and 2017. Total oral morphine milligram equivalents (MMEs) for inpatient use were calculated and used as the common unit of comparison. RESULTS: = 0.547, specificity 95%, sensitivity 58%) demonstrated that a psychiatric or chronic pain diagnosis (OR 3.95, p = 0.013, 95% CI 1.34-11.6), pre-operative opioid use (OR 8.65, p < 0.001, 95% CI 2.59-29.0), ASA class (OR 2.95, p = 0.025, 95% CI 1.14-7.63), and inpatient total MME (1.002, p < 0.001, 95% CI 1.001-1.003) were positive predictors of prolonged opioid use at 6-month follow-up, while inpatient muscle relaxant use (OR 0.327, p = 0.049, 95% CI 0.108-0.994) decreased the probability of prolonged opioid use. Patients in the pre-operative opioid use group had a significantly higher rate of opioid usage at 6 weeks (79% vs. 46%, p < 0.001), 3 months (51% vs. 14%, p < 0.001), and 6 months (40% vs. 5%, p < 0.001). CONCLUSIONS:Pre-operative opioid usage is associated with higher total inpatient opioid use and a significantly higher risk of long-term opiate usage at 6 months. Approximately 40% of pre-operative narcotic users will continue to consume narcotics at 6-month follow-up, compared with 5% of narcotic-naïve patients. These slides can be retrieved under Electronic Supplementary Material.

OBJECTIVE:Intraoperative cell salvage systems, or cell savers, are widely used for the management of blood loss in patients undergoing spine surgery. However, recent studies report conflicting evidence of their efficacy. The purpose of the meta-analysis was to investigate the efficacy of cell savers in reducing blood transfusion requirements in patients undergoing spine surgery. METHODS:Both retrospective and prospective studies that investigated the efficacy of cell savers in reducing transfusion requirements in spine surgery patients when compared with control patients were identified from MEDLINE, Embase, Cochrane Collaboration Library, Google Scholar, and Scopus databases. Outcome data extracted included number of patients receiving allogenic transfusions (transfusion rate); units of allogenic transfusions; postoperative hemoglobin; costs; operative time; and complications. RevMan 5 software was used to perform statistical analyses. A random-effects model was used to calculate pooled odds ratios (with 95% CIs) and weighted mean differences (WMDs [95% CI]) for dichotomous and continuous variables, respectively. RESULTS:Eighteen studies with 2815 patients in total were included in the meta-analysis. During spine surgery, the use of intraoperative cell salvage did not reduce the intraoperative (OR 0.66 [95% CI 0.30, 1.41]), postoperative (OR -0.57 [95% CI 0.20, 1.59]), or total transfusion (OR 0.92 [95% CI 0.43, 1.98]) rate. There was a reduction in the number of allogenic units transfused intraoperatively by a mean of 0.81 (95% CI -1.15, -0.48). However, there were no differences in the number of units transfused postoperatively (WMD -0.02 [95% CI -0.41, 0.38]) or the total units transfused (WMD 0.08 [95% CI -1.06, 1.22]). There were also no differences in operative time (WMD 19.36 [95% CI -2.43, 42.15]) or complications reported (OR 0.79 [95% CI 0.46, 1.37]) between groups. A difference in postoperative hemoglobin (WMD 0.54 [95% CI 0.11, 0.98]) between both groups was observed. CONCLUSIONS:Cell saver is efficacious at reducing intraoperative allogenic units transfused. There is no difference in transfusion rates, postoperative units transfused, and the total number of units transfused. Further cost analysis studies are necessary to evaluate the cost-effectiveness of this method of blood conservation.â–  CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: meta-analysis; strength of recommendation: low.

STUDY DESIGN/UNASSIGNED:This was a single-center retrospective review. OBJECTIVES/UNASSIGNED:To explore how age and gender affect PROMIS scores compared with traditional health-related quality of life (HRQL) in spine patients. METHODS/UNASSIGNED:Patients presenting with a primary complaint of back pain (BP) or neck pain (NP) were included. Legacy HRQLs were Oswestry Disability Index (ODI), Neck Disability Index (NDI), and Visual Analogue Scale (VAS). PROMIS Physical Function (PF), Pain Intensity (Int), and Pain Interference (Inf) were also administered to patients in a clinical setting. Patients were grouped by chief complaint, age (18-44, 45-64, 65+ years) and gender. Two parallel analyses were conducted to identify the effects of age and gender on patient-reported outcomes. Age groups were compared after propensity-score matching by VAS-pain and gender. Separately, genders were compared after propensity-score matching by age and VAS-pain. RESULTS/UNASSIGNED:= .022) but not PROMIS-Int or PROMIS-Inf. CONCLUSIONS/UNASSIGNED:Age and gender confound traditional HRQLs as well as PROMIS domains. However, PROMIS offers age and gender-specific scores, which traditional HRQLs lack.

Study Design/UNASSIGNED:Retrospective cohort study. Objective/UNASSIGNED:To investigate radiological differences in lumbar disc herniations (herniated nucleus pulposus [HNP]) between patients receiving microscopic lumbar discectomy (MLD) and nonoperative patients. Methods/UNASSIGNED:test and chi-square analyses compared differences in the groups, binary logistic regression analysis determined odds ratios (ORs), and decision tree analysis compared the cutoff values for risk factors. Results/UNASSIGNED:< .01). Conclusion/UNASSIGNED:Patients who underwent MLD treatment had significantly different axial HNP area, frequency of caudal migration, magnitude of cephalad/caudal migration, and disc herniation MRI signal compared to patients with nonoperative treatment.

Background/UNASSIGNED:Multilevel fusions and complex osteotomies to restore global alignment in adult spinal deformity (ASD) surgery can lead to increased operative time and blood loss. In this regard, we assessed factors predictive of perioperative blood product transfusion in patients undergoing long posterior spinal fusion for ASD. Methods/UNASSIGNED:A single-institution retrospective review was conducted on 909 patients with ASD, age > 18 years, who underwent surgery for ASD with greater than 4 levels fused. Using conditional inference tree analysis, a machine learning methodology, we sought to predict the combination of variables that best predicted increased risk for intraoperative percent blood volume lost and perioperative blood product transfusion. Results/UNASSIGNED: = .046). Conclusions/UNASSIGNED:Using a supervised learning technique, this study demonstrates that greater than 13 levels fused, ASA score > 1, 3-column osteotomy, and pelvic fixation are consistent risk factors for increased intraoperative percent blood volume lost and perioperative RBC transfusion. The addition of having a preoperative hemoglobin < 13.6 g/dL or undergoing a posterior column osteotomy conferred the highest risk for intraoperative blood loss. This information can assist spinal deformity surgeons in identifying at-risk individuals and allocating healthcare resources. Level of Evidence/UNASSIGNED:3.

Background/UNASSIGNED:Hospital-acquired venous thromboembolisms (HA-VTE) are a significant source of morbidity and mortality in spine surgery patients. The purpose of this study was to review HA-VTE rates at our institution and evaluate the prevalence of known risk factors in patients who developed HA-VTE among both neurosurgical and orthopedic spine surgeries. Methods/UNASSIGNED: < .05. Results/UNASSIGNED: < .001). Conclusions/UNASSIGNED:The overall HA-VTE rate at our institution was 0.94% (0.61% orthopedic, 1.87% neurosurgery). In patients who sustained VTE, neurosurgical patients had higher rates of active cancer and age >60 years, and orthopedic patients had higher EBL and rates of anterior-posterior surgery. This highlights the different patient populations between the 2 departments and the need for individualized thromboprophylaxis regimens. Level of Evidence/UNASSIGNED:4.

OBJECTIVE:Neck and back pain are highly prevalent conditions that account for major disability. The Neck Disability Index (NDI) and Oswestry Disability Index (ODI) are the two most common functional status measures for neck and back pain. However, no single instrument exists to evaluate patients with concurrent neck and back pain. The recently developed Total Disability Index (TDI) combines overlapping elements from the ODI and NDI with the unique items from each. This study aimed to prospectively validate the TDI in patients with spinal deformity, back pain, and/or neck pain. METHODS:This study is a retrospective review of prospectively collected data from a single center. The 14-item TDI, derived from ODI and NDI domains, was administered to consecutive patients presenting to a spine practice. Patients were assessed using the ODI, NDI, and EQ-5D. Validation of internal consistency, test-retest reproducibility, and validity of reconstructed NDI and ODI scores derived from TDI were assessed. RESULTS:A total of 252 patients (mean age 55 years, 56% female) completed initial assessments (back pain, n = 115; neck pain, n = 52; back and neck pain, n = 55; spinal deformity, n = 55; and no pain/deformity, n = 29). Of these patients, 155 completed retests within 14 days. Patients represented a wide range of disability (mean ODI score: 36.3 ± 21.6; NDI score: 30.8 ± 21.8; and TDI score: 34.1 ± 20.0). TDI demonstrated excellent internal consistency (Cronbach's alpha = 0.922) and test-retest reliability (intraclass correlation coefficient = 0.96). Differences between actual and reconstructed scores were not clinically significant. Subanalyses demonstrated TDI's ability to quantify the degree of disability due to back or neck pain in patients complaining of pain in both regions. CONCLUSIONS:The TDI is a valid and reliable disability measure in patients with back and/or neck pain and can capture each spine region's contribution to total disability. The TDI could be a valuable method for total spine assessment in a clinical setting, and its completion is less time consuming than that for both the ODI and NDI.

STUDY DESIGN:Retrospective review from a single institution. OBJECTIVE:To investigate the effect of hip osteoarthritis (OA) on spinopelvic compensatory mechanisms as a result of reduced hip range of motion (ROM) between sitting and standing. SUMMARY OF BACKGROUND DATA:Hip OA results in reduced hip ROM and contracture, causing pain during postural changes. Hip flexion contracture is known to reduce the ability to compensate for spinal deformity while standing; however, the effects of postural spinal alignment change between sitting and standing is not well understood. METHODS:Sit-stand radiographs of patients without prior spinal fusion or hip prosthesis were evaluated. Hip OA was graded by Kellgren-Lawrence grades and divided into low-grade (LOA; grade 0-2) and severe (SOA; grade 3 or 4) groups. Radiographic parameters evaluated were pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), PI-LL, thoracic kyphosis (TK), SVA, T1-pelvic angle (TPA), T10-L2, proximal femoral shaft angle (PFSA), and hip flexion (PT change-PFSA change). Changes in sit-stand parameters were compared between LOA and SOA groups. RESULTS:548 patients were included (LOA = 311; SOA = 237). After propensity score matching for age, body mass index, and PI, 183 LOA and 183 SOA patients were analyzed. Standing analysis demonstrated that SOA had higher SVA (31.1 vs. 21.7), lower TK (-36.2 vs. -41.1), and larger PFSA (9.1 vs. 7.4) (all p < .05). Sitting analysis demonstrated that SOA had higher PT (29.7 vs. 23.3), higher PI-LL (21.6 vs. 12.4), less LL (31.7 vs. 41.6), less TK (-33.2 vs. -38.6), and greater TPA (27.9 vs. 22.5) (all p < .05). SOA had less hip ROM from standing to sitting versus LOA (71.5 vs. 81.6) (p < .05). Therefore, SOA had more change in PT (15.2 vs. 7.3), PI-LL (20.6 vs. 13.7), LL (-21.4 vs. -13.1), and T10-L2 (-4.9 vs. -1.1) (all p < .001), allowing the femurs to change position despite reduced hip ROM. SOA had greater TPA reduction (15.1 vs. 9.6) and less PFSA change (86.7 vs. 88.8) compared with LOA (both p < .001). CONCLUSIONS:Spinopelvic compensatory mechanisms are adapted for reduced hip joint motion associated with hip OA in standing and sitting. LEVEL OF EVIDENCE:Level III.