Dana Cruz

A Comparison of Two Different Dosing Protocols for Tranexamic Acid in Posterior Spinal Fusion for Spinal Deformity: A Prospective, Randomized Trial.

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.

The impact of obesity on compensatory mechanisms in response to progressive sagittal malalignment

BACKGROUND CONTEXT Obesitys impact on standing sagittal alignment remains poorly understood, especially with respect to the role of the lower limbs. Given energetic expenditure in standing, a complete understanding of compensation in obese patients with sagittal malalignment remains relevant. PURPOSE This study compares obese and non-obese patients with progressive sagittal malalignment for differences in recruitment of pelvic and lower-limb mechanisms. STUDY DESIGN/SETTING Single-center retrospective review. PATIENT SAMPLE A total of 554 patients (277 obese, 277 non-obese) were identified for analysis. OUTCOME MEASURES Upper body alignment parameters: sagittal vertical axis (SVA) and T1 spinopelvic inclination (T1SPi). Compensatory lower-limb mechanisms: pelvic translation (pelvic shift [PS]), knee (KA) and ankle (AA) flexion, hip extension (sacrofemoral angle [SFA]), and global sagittal angle (GSA). METHODS Inclusion criteria were patients ≥18 years who underwent full-body stereographic x-rays. Included patients were categorized as non-obese (N-Ob: body mass index [BMI]<30 kg/m2) or obese (Ob: BMI≥30 kg/m2). To control for potential confounders, groups were propensity score matched by age, gender, and baseline pelvic incidence (PI), and subsequently categorized by increasing spinopelvic (pelvic incidence minus lumbar lordosis [PI-LL]) mismatch: <10°, 10°-20°, >20°. Independent t tests and linear regression models compared sagittal (SVA, T1SPi) and lower limb (PS, KA, AA, SFA, GSA) parameters between obesity cohorts. RESULTS A total of 554 patients (277 Ob, 277 N-Ob) were included for analysis and were stratified to the following mismatch categories: <10°: n=367; 10°-20°: n=91; >20°: n=96. Obese patients had higher SVA, KA, PS, and GSA than N-Ob patients (p<.001 all). Low PI-LL mismatch Ob patients had greater SVA with lower SFA (142.22° vs. 156.66°, p=.032), higher KA (5.22° vs. 2.93°, p=.004), and higher PS (4.91 vs. -5.20 mm, p<.001) than N-Ob patients. With moderate PI-LL mismatch, Ob patients similarly demonstrated greater SVA, KA, and PS, combined with significantly lower PT (23.69° vs. 27.14°, p=.012). Obese patients of highest (>20°) PI-LL mismatch showed greatest forward malalignment (SVA, T1SPi) with significantly greater PS, and a concomitantly high GSA (12.86° vs. 9.67°, p=.005). Regression analysis for lower-limb compensation revealed that increasing BMI and PI-LL predicted KA (r2=0.234) and GSA (r2=0.563). CONCLUSIONS With progressive sagittal malalignment, obese patients differentially recruit lower extremity compensatory mechanisms, whereas non-obese patients preferentially recruit pelvic mechanisms. The ability to compensate for progressive sagittal malalignment with the pelvic retroversion is limited by obesity.

Intraoperative Management of Adult Lumbar Scoliosis

The operative correction of adult lumbar scoliosis encompasses complex procedures with significant risk of complications. The population most afflicted by lumbar scoliosis is frequently more fragile with comorbid conditions making them less resilient to those complications. For these reasons, it is essential that the patient is carefully managed intraoperatively with the goal to reduce rates of preventable complications such as excessive blood loss, reduce intraoperative time, and improve patient outcomes overall. This chapter will explore several strategies used to manage patients during the perioperative period including, for example, with the use of specialized operative teams, dual surgeon procedures, neurophysiologic monitoring, antifibrinolytics, and other methods to improve patient safety.

Imaging Adult Lumbar Scoliosis

Radiographic assessment is an integral component of the evaluation and management of lumbar scoliosis. Although lumbar deformity is relatively common, the complexity and uniqueness of a patient’s specific deformity and symptoms necessitates a thorough assessment of each individual case. Fortunately for patients and clinicians, modern imaging modalities permit the evaluation of the bony, neuromuscular, and soft tissue components of the spine with exquisite detail. The spine surgeon is equipped with many tools used to evaluate a patient radiographically with guidance based on history, physical exam, and specific clinical questions. Some of these tools include conventional radiography, computed tomography (CT), and magnetic resonance imaging (MRI), each of which may be adapted or occasionally substituted as necessary to glean specific information. The primary goal of this chapter is to introduce the imaging modalities used to assess patients during each phase of evaluation and their applications to particular clinical scenarios.