Faculty Bibliography

: Study Design. Retrospective review, full body radiographic analysis of adult patients with sagittal spinal malalignment.Objective. Investigate the compensatory mechanisms involved in the sagittal plane of the body following progressive spinal sagittal malalignment, and study the impact of age on compensatory mechanisms recruitment.Summary of Background Data. Sagittal spinal malalignment (SSM) patients recruit compensatory mechanisms to maintain erect posture and horizontal gaze. Mechanisms such as pelvic retroversion, knee flexion and pelvic shift have been proposed, but how they contribute and how age affects their recruitment is poorly understood.Methods. Retrospective review of adult SSM patients who underwent full standing axis stereoradiography EOS(c). Radiographic measurements were performed with Surgimap(c). Patients were categorized based on the mismatch between pelvic incidence and lumbar lordosis (PI-LL). Compensatory mechanisms were normalized to each patient's PI-LL and compared by mismatch groups. In addition, patients were subcategorized into two age groups (>/=65yrs and <65yrs) and compared within the same groups of mismatch.Results. 161 patients with a mean age of 62.93+/-12.8yrs. Mean SVA 62.3+/-61.5mm, PT 29.2+/-8.4 degrees , and PI-LL 21.0+/-14.9 degrees . Mismatch groups were: Group 1: PI-LL 0-10 degrees , Group 2: 10-20 degrees , Group 3: 20-30 degrees , and Group 4: > 30 degrees . There were significant differences between all groups in regards to thoracic kyphosis (TK), pelvic tilt (PT), knee flexion angle (KA), and pelvic shift (P.Sh) by ANOVA (p<0.001). As PI-LL increased, TK and PT contribution to the compensation cascade decreased and KA and P.Sh contribution increased. Patients with PI-LL of > 30 degrees who were older had significantly less PT and more TK than patients with similar PI-LL who were younger.Conclusions. Spino-pelvic mismatch is an important driver in SSM. Pelvic retroversion and flattening of thoracic kyphosis (reduction) become exhausted with increasing mismatch, at which point there appears to be a steady transfer of compensation towards significant participation of the lower limbs. Further analysis suggests differential recruitment of these compensatory mechanisms based upon age.

STUDY DESIGN: This is a prospective, randomized, double-blinded comparison of tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and placebo used intraoperatively in patients with adult spinal deformity. OBJECTIVE: The purpose of this study was to provide high-quality evidence regarding the comparative efficacies of TXA, EACA, and placebo in reducing blood loss and transfusion requirements in patients undergoing posterior spinal fusion surgery. SUMMARY OF BACKGROUND DATA: Spine deformity surgery usually involves substantial blood loss. The antifibrinolytics TXA and EACA have been shown to improve hemostasis in large blood loss surgical procedures. METHODS: Fifty-one patients undergoing posterior spinal fusion of at least 5 levels for correction of adult spinal deformity were randomized to 1 of 3 treatment groups. Primary outcome measures included intraoperative estimated blood loss, total loss, (estimated blood loss + postoperative blood loss), and transfusion rates. RESULTS: Patients received TXA (n = 19), EACA (n = 19), or placebo (n = 13) in the operating room (mean ages: 60, 47, and 43 yr, respectively); TXA patients were significantly older and had larger estimated blood volumes than both other groups. Total losses were significantly reduced for EACA versus control, and there was a demonstrable but nonsignificant trend toward reduced intraoperative blood loss in both antifibrinolytic arms versus control. EACA had significant reductions in postoperative blood transfusions versus TXA. CONCLUSION: The findings in this study support the use of antifibrinolytics to reduce blood loss in posterior adult spinal deformity surgery. LEVEL OF EVIDENCE: 1.

BACKGROUND CONTEXT: Spine surgery is usually associated with large blood loss necessitating blood transfusions. Blood loss-associated morbidity can be due to direct risks, such as hypotension and organ damage, or as result of blood transfusions. The antifibrinolytic, tranexamic acid (TXA) is a lysine analogues which inhibits activation of plasminogen and has shown to be beneficial in reducing surgical blood loss. PURPOSE: The purpose of the meta-analysis is to consolidate the findings of randomized controlled trials (RCTs) investigating the use of TXA on surgical bleeding in spine surgery. STUDY DESIGN: Meta-analysis STUDY SAMPLE: RCTs investigating effectiveness of intravenous TXA in reducing blood loss in spine surgery, compared to a placebo/ no treatment group. METHODS: MEDLINE, Embase, Cochrane controlled trials register and Google Scholar were used to identify RCTs published before January 2014 that examined the effectiveness of intravenous TXA on reduction of blood loss and blood transfusions, compared to a placebo/ no treatment group in spine surgery. Meta analysis was performed using RevMan 5. Weighted mean difference was used to summarize findings across the trials for continuous outcomes. Dichotomous data were expressed as risk ratio with 95% confidence intervals (CI). A p < 0.05 was considered statistically significant. RESULTS: Eleven RCTs were included for TXA (644 total patients). TXA reduced intraoperative, postoperative and total blood loss by an average of 219 ml ([-322,-116], p<0.05), 119 ml ([-141,-98], p<0.05) and 202 ml ([-299, -105], p<0.05) respectively. TXA led to a reduction in proportion of patients who received a blood transfusion (RR 0.67 ([0.54, 0.83], p <0.05) relative to placebo. There was one myocardial infarction (MI) in the TXA group and one deep vein thrombosis (DVT) in placebo. CONCLUSION: TXA reduces surgical bleeding and transfusion requirements in patients undergoing spine surgery. TXA does not appear to be associated with an increased incidence of pulmonary embolism, DVT, or MI.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the rate and causes of unplanned readmissions after surgical treatment of common degenerative lumbar pathologies within 90 days. SUMMARY OF BACKGROUND DATA: With pay-for performance and bundled payment compensation models being implemented; there is a growing emphasis to decrease the number of unplanned readmissions after surgery. Reports on degenerative lumbar spine pathology readmission rates are often obtained from national databases that lack clinical detail. Less published are the results from single-center institutions. METHODS: Hospital administrative database from a single-tertiary institution was queried to identify patients who underwent surgery for 6 common lumbar pathologies during a period from 2011 to 2013. All readmissions within 90 days of discharge were reviewed for cause and rate of unplanned readmissions was calculated. RESULTS: A total of 1306 patients were identified who underwent surgery for various lumbar pathologies during a 2-year time period. There were a total of 70 readmissions captured in the database that included 14 planned, 43 unplanned readmissions, and 13 coding errors. The unplanned readmission rate varied between 2.1% and 7.1% depending on pathology, with an overall rate of 3.3% within 90 days of discharge. Index length of stay, discharge disposition, severity of illness scores, and surgical approach were associated with readmission. The addition of fusion to decompression procedures did not seem to increase readmission rates. Surgical site infections and wound complications were the 2 most common reasons for readmissions accounting for 72% of all readmissions during the 90-day postdischarge period. CONCLUSION: The rate of readmission after surgery for common lumbar degenerative pathologies is relatively low. Surgical site infections and wound complications were the most common cause of readmission in this patient cohort. LEVEL OF EVIDENCE: 4.

The purpose of this study was to investigate the potential of a high-throughput, easily implemented, cost-effective, video analysis software-based mobility protocol to quantify spine kinematics. This prospective cohort study of clinical biomechanics implemented 2-dimensional (2D) image processing at a tertiary-care academic institution. Ten healthy, able-bodied volunteers were recruited for 2D videography of gait and functional motion. The reliability of a 2D video analysis software program for gait and range of motion metrics was evaluated over 2 independent experimental sessions, assessing for inter-trial, inter-session, and inter-rater reliability. Healthy volunteers were evaluated for simple forward and side bending, rotation, treadmill stride length, and more complex seated-to-standing tasks. Based on established intraclass correlation coefficients, results indicated that reliability was considered good to excellent for simple forward and side bending, rotation, stride length, and more complex sit-to-standing tasks. In conclusion, a cost-effective, 2D, video analysis software-based mobility protocol represents a feasible and clinically useful approach for objective spine kinematics and gait metrics. As the complication rate of operative management in the setting of spinal deformity is weighed against functional performance and quality of life measures, an objective analysis tool in combination with an appropriate protocol will aid in clinical assessments and lead to an increased evidence base for management options and decision algorithms.

Intraoperative monitoring (IOM) of spinal cord and nerve root injury through somatosensory evoked po - tentials (SSEP), transcranial motor evoked potentials (TcMEP), spontaneous electromyography (sEMG), and triggered electromyography (tEMG) modalities is vital during spinal surgery. However, there are currently no practice guidelines or practice patterns for the utilization of unimodal and multimodal IOM for specific surger - ies. This study reviews IOM modalities and documents practice patterns of spine surgeons at our single-center tertiary hospital about their use of various IOM modali - ties on 23 spinal procedures. As different intraoperative monitoring modalities have shown to have different sen - sitivities and specificities, devising practice guidelines for IOM utilization in specific spinal procedures should be considered.

BACKGROUND: Unplanned hospital readmissions result in significant clinical and financial burdens to patients and the healthcare system. Readmission rates and causes have been investigated using large administrative databases which have certain limitations in data reporting and coding. The objective of this study was to provide a description of 90 day post-discharge readmissions following surgery for common degenerative cervical spine pathologies at a large-volume tertiary hospital. The study also compared the readmission rates of patients who underwent anterior- and posterior-approach procedures. METHODS: The administrative records from a single-center, high-volume tertiary institution were queried using ICD-9 codes for common cervical pathology over a three year period to determine the rate and causes of readmissions within the 90 days following the index surgery. RESULTS: A total of 768 patients underwent degenerative cervical spine surgery during the three year study period. Within 90 days of discharge, 24 (3.13%) patients were readmitted; 16 (2.06%) readmissions were planned for lumbar surgery; 8 (1.04%) readmissions were unplanned. 640 patients underwent procedures involving an anterior approach and 128 patients underwent procedures involving a posterior approach. There were 14 (2.17%) planned readmissions in the anterior group and 2 (1.5%) in the posterior group. The unplanned readmission rate was 0.63% (4 patients) and 3.13% (4 patients) in the anterior and posterior groups, respectively. (p=0.0343). CONCLUSION: The 90 day post-discharge unplanned readmission rate that followed elective degenerative cervical spine surgery was 1.04%. The unplanned readmission rate associated with posterior-approach procedures (3.13%) was significantly higher than that of anterior-approach procedures (0.63%). LEVEL OF EVIDENCE: IV.

BACKGROUND: Multilevel spinal fusions have typically been associated with significant blood loss. Previous studies have shown a reduction in blood loss with antifibrinolytics in both adolescent and adult spinal deformity patients. While this has been mirrored in other subspecialties as well, the dosing of TXA remains highly variable. To date, there remains a paucity of data guiding dosing for TXA in spine surgery and orthopedic surgery as a whole. METHODS/DESIGN: One hundred and fifty patients from 3 institutions (50 each site) will be consecutively enrolled and randomized to either a high dose of TXA (50mg/kg loading followed by 20mg/kg hourly) or a lose dose (10mg/kg, then 1mg/kg hourly). Both surgeons and patients will be blinded to the treatment group. Primary outcomes will be perioperative blood loss, drain output, and transfusion rate. Secondary outcomes will be length of stay, complications, and overall cost. DISCUSSION: The primary goal of this study is to provide level-1 comparative data for two TXA dosing regimens in adult spinal deformity surgery. Management of blood loss remains a critical factor in reducing complications during spinal deformity surgery. The null hypothesis is that there is no difference between high- and low-dose TXA with respect to any of the primary or secondary outcomes.