Faculty Bibliography

BACKGROUND:Adult sagittal spinal deformity (SSD) leads to the recruitment of compensatory mechanisms to maintain standing balance. After regional spinal compensation is exhausted, lower extremity compensation is recruited. Knee flexion, ankle flexion, and sacrofemoral angle increase to drive pelvic shift posterior and increase pelvic tilt. We aim to describe 2 summary angles termed ankle-pelvic angle (APA) and global lower extremity angle (GLA) that incorporate all aspects of lower extremity and pelvic compensation in a comprehensive measurement that can simplify radiographic analysis. METHODS:Full-body sagittal stereotactic radiographs were retrospectively collected and digitally analyzed. Spinal and lower extremity alignment were quantified with existing measures. Two angles-APA and GLA-were drawn as geometrically complementary angles to T1-pelvic angle (TPA) and global sagittal axis (GSA), respectively. Regression analysis was used to represent the predictive relationship between TPA and APA and between GSA and GLA. RESULTS:= .005). CONCLUSIONS:TPA and GSA are measures of global spinal alignment and APA and GLA, respectively, and are geometrically complementary angles that vary proportionately to SSD and balance the body. APA and GLA increase in SSD patients with lower extremity compensation and decrease with corrective surgery. LEVEL OF EVIDENCE/METHODS:4. CLINICAL RELEVANCE/CONCLUSIONS:APA and GLA offer a concise and simple method of communicating pelvic and lower extremity compensation.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:Assess trends in sports-related cervical spine trauma using a pediatric inpatient database. SUMMARY OF BACKGROUND DATA/BACKGROUND:Injuries sustained from sports participation may include cervical spine trauma such as fractures and spinal cord injury(SCI). Large database studies analyzing sports-related cervical trauma in the pediatric population are currently lacking. METHODS:KID was queried for patients with external causes of injury secondary to sports-related activities from 2003-2012. Patients were further grouped for cervical spine injury type, including C1-4 & C5-7 fracture with/without spinal cord injury (SCI), dislocation, and SCI without radiographic abnormality (SCIWORA). Patients were grouped by age into Children(4-9),Pre-Adolescents(Pre,10-13),and Adolescents(14-17). Kruskall-Wallis tests with post-hoc Mann-Whitney-U's identified differences in cervical spine injury type across age groups and sport type. Logistic regression found predictors of TBI and specific cervical injuries. RESULTS:38,539pts identified(12.76yrs,24.5%F). Adolescents had the highest rate of sports injuries per year(p < 0.001). Adolescents had the highest rate of any type of cervical spine injury, including C1-4 and C5-7 fracture with and without SCI, dislocation, and SCIWORA(all p < 0.001). Adolescence increased odds for C1-4 fracture w/o SCI 3.18x, C1-4 fx w/ SCI by 7.57x, C5-7 fx w/o SCI 4.11x, C5-7 w/SCI 3.63x, cervical dislocation 1.7x, and cervical SCIWORA 2.75x, all p < 0.05. Football injuries rose from 5.83% in 2009 to 9.14% in 2012 (p < 0.001), and were associated with more SCIWORA(1.6%vs1.0%,p = 0.012), and football injuries increased odds of SCI by 1.56x. Concurrent TBI was highest in Adolescents at 58.4%(Pre:26.6%,Child:4.9%,p < 0.001), and SCIWORA was a significant predictor for concurrent TBI across all sports(OR: 2.35[1.77-3.11], p < 0.001). CONCLUSIONS:Adolescent athletes had the highest rates of upper/lower cervical fracture, dislocation, and SCIWORA. Adolescence and SCIWORA were significant predictors of concurrent TBI across sports. The increased prevalence of cervical spine injury with age sheds light on the growing concern for youth sports played at a competitive level, and supports recently updated regulations aimed at decreasing youth athletic injuries. LEVEL OF EVIDENCE/METHODS:3.

Adult spinal deformity is a broad spectrum of disorders that are becoming more prevalent with an ageing population. In those with moderate to severe deformity, surgical correction of spinal alignment is an increasingly common treatment and has demonstrated improvement in patients"™ quality of life. Whilst continued research in risk stratification, advances in surgical techniques, and preoperative optimization has taken place, rates of adverse outcomes following surgery for adult spinal deformity are still frequent. Pain is a common complaint after spinal deformity correction; however, whether this pain is deemed a "˜normal"™ amount, or a "˜pathological"™ pain has not been well characterized in the literature. This paper aims to provide a framework for evaluating pain after spinal deformity correction surgery in order to guide clinical decision making.

BACKGROUND CONTEXT/BACKGROUND:Expandable cages (EXP) are being more frequently utilized in transforaminal lumbar interbody fusions (TLIF). EXP were designed to reduce complications related to neurological retraction, enable better lordosis restoration, and improve ease of insertion, particularly in the advent of minimally invasive surgical (MIS) techniques, however they are exponentially more expensive than the nonexpandable (NE) alternative. PURPOSE/OBJECTIVE:To investigate the clinical results of expandable cages in single level TLIF. STUDY DESIGN/SETTING/METHODS:Retrospective review at a single institution. PATIENT SAMPLE/METHODS:Two hundred and fifty-two single level TLIFs from 2012 to 2018 were included. OUTCOME MEASURES/METHODS:Clinical characteristics, perioperative and neurologic complication rates, and radiographic measures. METHODS:Patients ≥18 years of age who underwent single level TLIF with minimum 1 year follow-up were included. OUTCOME MEASURES/METHODS:clinical characteristics, perioperative and neurologic complications. Radiographic analysis included pelvic incidence-lumbar lordosis (PI-LL) mismatch, segmental lumbar lordosis (LL) mismatch, disc height restoration, and subsidence ≥2 mm. Statistical analysis included independent t tests and chi-square analysis. For nonparametric variables, Mann-Whitney U test and Spearman partial correlation were utilized. Multivariate regression was performed to assess relationships between surgical variables and recorded outcomes. For univariate analysis significance was set at p<.05. Due to the multiple comparisons being made, significance for regressions was set at p<.025 utilizing Bonferroni correction. RESULTS:Two hundred and fifty-two TLIFs between 2012 and 2018 were included, with 152 NE (54.6% female, mean age 59.28±14.19, mean body mass index (BMI) 28.65±5.38, mean Charlson Comorbidity Index (CCI) 2.20±1.89) and 100 EXP (48% female, mean age 58.81±11.70, mean BMI 28.68±6.06, mean CCI 1.99±1.66) with no significant differences in demographics. Patients instrumented with EXP cages had a shorter length of stay (3.11±2.06 days EXP vs. 4.01±2.64 days NE; Z=-4.189, p<.001) and a lower estimated blood loss (201.31±189.41 mL EXP vs. 377.82±364.06 mL NE; Z=-6.449, p<.001). There were significantly more MIS-TLIF cases and bone morphogenic protein (BMP) use in the EXP group (88% MIS, p<.001 and 60% BMP, p<.001) as illustrated in Table 1. There were no significant differences between the EXP and NE groups in rates of radiculitis and neuropraxia. In multivariate regression analysis, EXP were not associated with a difference in perioperative outcomes or complications. Radiographic analyses demonstrated that the EXP group had a lower PI-LL mismatch than the NE cage group at baseline (3.75±13.81° EXP vs. 12.75±15.81° NE; p=.001) and at 1 year follow-up (3.81±12.84° EXP vs. 8.23±12.73° NE; p=.046), but change in regional and segmental alignment was not significantly different between groups. Multivariate regression demonstrated that EXP use was a risk factor for intraoperative subsidence (2.729[1.185-6.281]; p=.018). CONCLUSIONS:Once technique was controlled for, TLIFs utilizing EXP do not have significantly improved neurologic or radiographic outcomes compared with NE. EXP increase risk of intraoperative subsidence. These results question the value of the EXP given the higher cost.

Advanced age and other comorbid factors correlate with age-increased morbidity associated with spine surgery. It is crucial that spine surgeons critically assess perioperative risks versus postoperative benefits of spine surgery in the growing elderly population. Close coordination between the surgeon, anesthesia team and the patient can minimize complications, improve function and contribute to decreased costs of these complex procedures.

Background/UNASSIGNED:Optimal acetabular component orientation in total hip arthroplasty (THA) is a necessity in achieving a stable implant. Although there has been considerable debate in the literature concerning the safe zone, to date, there has not been any review to determine if these references are consistent with the definition applied by Lewinnek et al. in 1978. Therefore, this article aims to examine the available literature in the PubMed database to determine how often a correct reference to the safe zone as defined by Lewinnek was applied to discussions regarding THA. Methods/UNASSIGNED:A search for literature in the PubMed database was performed for articles from 1978 to 2019. Search criteria included terms 'Lewinnek,' 'safe zone,' and 'total hip arthroplasty.' Exclusions included abstract-only articles, non-English articles, articles unrelated to THA, and those lacking full content. Results/UNASSIGNED:A review of literature yielded 147 articles for inclusion. Overall, only 11% (17) cited the Lewinnek article correctly. Forty-five percent (66) of articles referenced measurements in the supine position, 18% (26) referenced other positions, and 37% (55) did not specify. Nineteen percent (28) reported measurements of the acetabular cup orthogonal to the anterior pelvic plane, while 73% (108) did not, and 7% (11) did not specify. Twenty-three percent (34) measured from computed tomography scans instead of other methods. Conclusions/UNASSIGNED:In the discussion of the safe zone regarding THA, only 11% of articles listed are consistent with the definition established by Lewinnek. This warrants further investigation into a consistent application of the term and its implications for THA implant stability and dislocation rates.

BACKGROUND:As the opioid crisis has gained national attention, there have been increasing efforts to decrease opioid usage. Simultaneously, patient satisfaction has been a crucial metric in the American health care system and has been closely linked to effective pain management in surgical patients. The purpose of this study was to examine rates of pain medication prescription and concurrent patient satisfaction in spine surgery patients. METHODS:test of independence was used to compare percentages, and 1-way analysis of variance was used to compare means across quarters. RESULTS:value range, .359-.988). CONCLUSIONS:Over the studied time period, opioid use decreased and nonopioid prescriptions increased during hospitalization, whereas satisfaction scores remained unchanged. These findings indicate an increasing effort in reducing opioid use among providers and suggest the ability to do so without affecting overall satisfaction rates. LEVEL OF EVIDENCE/METHODS:4. CLINICAL RELEVANCE/CONCLUSIONS:The opioid epidemic has highlighted the need to reduce opioid usage in orthopedic spine surgery. This study reviews the trends for inpatient management of post-op pain in orthopedic spine surgery patients in relation to patient satisfaction. There was a significant increase in non-opioid analgesic pain medications, and a reduction in opioids during the study period. During this time, patient satisfaction as measured by Press-Ganey surveys did not show a decrease. This demonstrates that treatment of post-operative pain in orthopedic spine surgery patients can be managed with less opioids, more multimodal analgesia, and patient satisfaction will not be affected.

BACKGROUND:The Miller et al adult spinal deformity frailty index (ASD-FI) correlates with complication risk; however, its development was not rooted in clinical outcomes, and the 40 factors needed for its calculation limit the index's clinical utility. The present study aimed to develop a simplified, weighted frailty index for ASD patients METHODS: This study is a retrospective review of a single-center database. Component ASD-FI parameters contributing to overall ASD-FI score were assessed via Pearson correlation. Top significant, clinically relevant factors were regressed against ASD-FI score to generate the modified ASD-FI (mASD-FI). Component mASD-FI factors were regressed against incidence of medical complications, and factor weights were calculated from regression of these coefficients. Total mASD-FI score ranged from 0 to 21, and was calculated by summing weights of expressed parameters. Linear regression and published ASD-FI cutoffs generated corresponding mASD-FI frailty cutoffs: not frail (NF, <7), frail (7-12), severely frail (SF, >12). Analysis of variance assessed the relationship between frailty category and validated baseline measures of pain and disability at baseline. RESULTS:= .001). CONCLUSIONS:This study modifies an existing ASD frailty index and proposes a weighted, shorter mASD-FI. The mASD-FI relies less on patient-reported variables, and it weights component factors by their contribution to adverse outcomes. Because increasing mASD-FI score is associated with inferior clinical measures of pain and disability, the mASD-FI may serve as a valuable tool for preoperative risk assessment.

The aim of this study was to investigate the cost utility of treating non-frail versus frail or severely frail adult spinal deformity (ASD) patients. 79 surgical ASD patients >18 years with available frailty and ODI data at baseline and 2-years post-surgery (2Y) were included. Utility data was calculated using the ODI converted to the SF-6D. QALYs utilized a 3% discount rate to account for decline to life expectancy (LE). Costs were calculated using the PearlDiver database. ICER was compared between non-operative (non-op.) and operative (op.) NF and F/SF patients at 2Y and LE. When compared to non-operative ASD, the ICER was $447,943.96 vs. $313,211.01 for NF and F/SF at 2Y, and $68,311.35 vs. $47,764.61 for NF and F/SF at LE. Frail and severely frail patients had lower cost per QALY compared to not frail patients at 2Y and life expectancy, and had lower ICER values when compared to a non-operative cohort of ASD patients. While these results support operative correction of frail and severely frail patients, it is important to note that these patients are often at worse baseline disability, which is closely related to frailty scores, and have more opportunity to improve postoperatively. Furthermore, there may be a threshold of frailty that is not operable due to the risk of severe complications that is not captured by this analysis. While future research should investigate economic outcomes at extended follow up times, these findings support the cost effectiveness of ASD surgery at all frailty states.

STUDY DESIGN/METHODS:This study is a single-center retrospective radiographic review. OBJECTIVES/OBJECTIVE:The objective of this study is to evaluate a novel measurement parameter, mandibular slope (MS), as a measure of horizontal gaze. INTRODUCTION/BACKGROUND:Assessment of sagittal spinal alignment is essential in the evaluation of spinal deformity patients. Ability to achieve a horizontal gaze, a parameter of sagittal alignment, is needed for the performance of daily activities. Standard measures of horizontal gaze, including the gold-standard chin-brow to vertical angle (CBVA) and the surrogate measures McGregor's line (McGS) and Chamberlain's line (CS), require high-quality imaging, precise head positioning, and reliance on difficult to view visual landmarks. A novel measurement parameter, MS, utilizing the caudal margin of the mandible on standard lateral spine radiographs is proposed. METHODS:90 radiographs from spine deformity patients with or without spinal implants from a single center were evaluated. Three spine surgery fellows independently measured CBVA, McGS, CS, and MS at two timepoints at least one week apart to assess accuracy and reliability. MS was measured as the angle created by the inferior edge of the mandibular body and the horizontal. Formulas for calculating CBVA based on the above parameters were derived and compared to the actual CBVA. RESULTS:Mean age was 49.7 years, 76 females and 14 males. CBVA correlated with CS, McGS, and MS, r = 0.85, 0.81, and 0.80, respectively (p < 0.001). Standard error between real CBVA and calculated CBVA using CS (0.4 ± 4.79) and McGS (0.4 ± 3.9) was higher than that calculated using MS (- 0.2 ± 4.3). ICC demonstrated the highest inter-observer reliability with MS (0.999). MS had the highest intra-observer reliabilities 0.975, 0.981, and 0.988 (p < 0.001); CS and McGS also demonstrated high intra-observer reliability. CONCLUSIONS:MS is a promising measure of horizontal gaze that correlates highly with CBVA, has excellent intra- and inter-observer reliability with CBVA, and is easily measured using standard lateral spine radiographs.