Faculty Bibliography

It's increasingly common for surgeons to operate on more challenging cases and higher risk patients, resulting in longer op-time and inpatient LOS. Factors predicting extended op-time and LOS for cervical deformity (CD) patients are understudied. This study identified predictors of extended op-time and length of stay (LOS) after CD-corrective surgery. CD patients with baseline (BL) radiographic data were included. Patients were stratified by extended LOS (ELOS; >75th percentile) and normal LOS (N-LOS; <75th percentile). Op-time analysis excluded staged cases, cases >12 h. A Conditional Variable Importance Table used non-replacement sampling set of Conditional Inference trees to identify influential factors. Mean comparison tests compared LOS and op-time for top factors. 142 surgical CD patients (61 yrs, 62%F, 8.2 levels fused). Op-time and LOS were 358 min and 7.2 days; 30% of patients experienced E-LOS (14 ± 13 days). Overlapping predictors of E-LOS and op-time included levels fused (>7 increased LOS 2.7 days; >5 increased op-time 96 min, P < 0.001), approach (anterior reduced LOS 3.0 days; combined increased op-time 69 min, P < 0.01), BMI (>38 kg/m² increased LOS 8.1 days; >39 kg/m² increased op-time 17 min), and osteotomy (LOS 2.0 days, op-time 62 min, P < 0.005). BL cervical parameters increased LOS and op-time: cSVA (>42 mm increased LOS; >50 mm increased op-time, P < 0.030), C0 slope (>@-0.9° increased LOS, >0.3° increased op-time, P < 0.003.) Additional op-time predictors: prior cervical surgery (p = 0.004) and comorbidities (P = 0.015). Other predictors of E-LOS: EBL (P < 0.001), change in mental status (P = 0.001). Baseline cervical malalignment, levels fused, and osteotomy predicted both increased op-time and LOS. These results can be used to better optimize patient care, hospital efficiency, and resource allocation.

OBJECTIVE:In the setting of a previous proximal fusion, an asymmetric 3-column osteotomy (3CO) can provide tremendous deformity correction. Our goal was to evaluate outcomes and complications of asymmetric 3CO through the proximal fusion mass, for coronal malalignment in patients with previous long thoracic fusion for adolescent idiopathic scoliosis. METHODS:This was a retrospective case series. Thirteen individuals with a history of a long thoracic fusion underwent asymmetric 3CO for persistent coronal malalignment. Clinical chart review was conducted to determine perioperative complications and radiographs evaluated for alignment. RESULTS:Thirteen patients (age: 57.8 ± 12.2 years; 0 male, 13 female) completed a mean follow-up of 42.4 months. There was significant improvement in coronal and sagittal alignment, and pelvic incidence-lumbar lordosis postoperatively (P < 0.05). One patient developed lower-extremity weakness requiring revision decompression 72 hours postoperatively; the weakness subsequently resolved. One patient had a foot drop postoperatively. At final follow-up, 12 of 13 patients had grade 1 fusion at the osteotomy site; 1 patient had a grade 2 fusion. None of the patients developed a pseudarthrosis, or superficial or deep infections. CONCLUSIONS:Patients with a history of previous thoracic fusion for adolescent idiopathic scoliosis and coronal malalignment may develop painful degeneration of the segments caudal to the fusion as adults. In this setting, extension of fusion to the sacropelvis alone may worsen the patient's coronal alignment. An asymmetric 3CO may be considered at the proximal fusion mass to achieve realignment objectives, with an acceptable complication rate and an expected improvement in outcomes.

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.

MINI: 172 patients underwent a primary TLIF. Those receiving <250 total MME (44%) as an inpatient had a 3.73 (odds ratio) times smaller probability of requiring opioids at 6 month follow-up. Patients who received >500 total MME (27%) had a 4.84 times greater probability of requiring opioids at 6 month follow-up.

STUDY DESIGN/METHODS:Single institution retrospective clinical review. OBJECTIVE:To investigate the relationship between levels fused and clinical outcomes in patients undergoing open and minimally invasive surgical (MIS) lumbar fusion. SUMMARY OF BACKGROUND DATA/BACKGROUND:Minimally invasive spinal fusion aims to reduce the morbidity associated with conventional open surgery. As multilevel arthrodesis procedures are increasingly performed using MIS techniques, it is necessary to weigh the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length. METHODS:Patients undergoing <4 level lumbar interbody fusion were stratified by surgical technique (MIS or open), and grouped by fusion length: 1-level, 2-levels, 3+ levels. Demographics, Charlson Comorbidity Index (CCI), surgical factors, and perioperative complication rates were compared between technique groups at different fusion lengths using means comparison tests. RESULTS:Included: 361 patients undergoing lumbar interbody fusion (88% transforaminal, 14% lateral; 41% MIS). Breakdown by fusion length: 63% 1-level, 22% 2-level, 15% 3+ level. Op-time did not differ between groups at 1-level (MIS: 233 min vs. Open: 227, P = 0.554), though MIS at 2-levels (332 min vs. 281) and 3+ levels (373 min vs. 323) were longer (P = 0.033 and P = 0.231, respectively). While complication rates were lower for MIS at 1-level (15% vs. 30%, P = 0.006) and 2-levels (13% vs. 27%, P = 0.147), at 3+ levels, complication rates were comparable (38% vs. 35%, P = 0.870). 3+ level MIS fusions had higher rates of ileus (13% vs. 0%, P = 0.008) and a trend of increased adverse pulmonary events (25% vs. 7%, P = 0.110). MIS was associated with less EBL at all lengths (all P < 0.01) and lower rates of anemia at 1-level (5% vs. 18%, P < 0.001) and 2-levels (7% vs. 16%, P = 0.193). At 3+ levels, however, anemia rates were similar between groups (13% vs. 15%, P = 0.877). CONCLUSION/CONCLUSIONS:MIS lumbar interbody fusions provided diminishing clinical returns for multilevel procedures. While MIS patients had lower rates of perioperative complications for 1- and 2-level fusions, 3+ level MIS fusions had comparable complication rates to open cases, and higher rates of adverse pulmonary and ileus events. LEVEL OF EVIDENCE/METHODS:3.

Introduction: Orthopaedic surgeons (OS) and neurosurgeons (NS) both perform cervical total disc replacement (cTDR) procedures. This study evaluated disparities in demographics, comorbidities, laboratory values, surgical and hospital-related parameters, and 30-day outcomes between OS and NS patients after single-level elective cTDR.
Method(s): The American College of Surgeons NSQIP database was used to identify single-level elective cTDR patients from 2008 to 2016. Demographics, comorbidities, laboratory values, operative- and hospital-related factors, and 30-day postoperative outcomes were compared between the OS (n = 769) and NS (n = 1,443) groups with univariate analysis. Regression models were developed to find potential predictive factors for 30-day postoperative complications.
Result(s): The OS patients were younger and more likely to be white (all, p <= 0.012). Comorbidities and preoperative laboatory values were mostly comparable, although OS patients has lower rates of diabetes mellitus (4.55% vs 8.04%; p = 0.002) and corticosteroid use (0.65% vs 2.70%; p = 0.001) than NS patients. The OS and NS patients also had comparable operative times (111 vs 112 minutes; p = 0.737), and rates of 30-day complications (1.2% vs 1.1%; p = 0.896), reoperations (0.4% vs 0.7%; p = 0.51), and readmissions (1.2% vs 1.1%; p = 0.841). Patient age was a significant predictor of major complications (odds ratio 1.079; p = 0.019) based on regression analysis, but surgeon specialty was not for any complications (p >= 0.13).
Conclusion(s): Neurosurgeons had a higher operative volume, but 30-day postoperative outcomes between the 2 groups were comparable. Surgeon specialty was not predictive for 30-day postoperative outcomes. Orthopaedic surgeons might be underperforming cTDR compared with neurosurgeons, despite comparable 30-day postoperative outcomes.
Copyright

BACKGROUND:Currently, the functional status of patients undergoing spine surgery is assessed with quality-of-life questionnaires, and a more objective and quantifiable assessment method is lacking. Dr. Jean Dubousset conceptually proposed a four-component functional test, but to our knowledge, reference values derived from asymptomatic individuals have not yet been reported, and these are needed to assess the test's clinical utility in patients with spinal deformities. QUESTIONS/PURPOSES/OBJECTIVE:(1) What are the reference values for the Dubousset Functional Test (DFT) in asymptomatic people? (2) Is there a correlation between demographic variables such as age and BMI and performance of the DFT among asymptomatic people? METHODS:This single-institution prospective study was performed from January 1, 2018 to May 31, 2018. Asymptomatic volunteers were recruited from our college of medicine and hospital staff to participate in the DFT. Included participants did not report any musculoskeletal problems or trauma within 5 years. Additionally, they did not report any history of lower limb fracture, THA, TKA, or patellofemoral arthroplasty. Patients were also excluded if they reported any active medical comorbidities. Demographic data collected included age, sex, BMI, and self-reported race. Sixty-five asymptomatic volunteers were included in this study. Their mean age was 42 ± 15 years; 27 of the 65 participants (42%) were women. Their mean BMI was 26 ± 5 kg/m. The racial distribution of the participants was 34% white (22 of 65 participants), 25% black (16 of 65 participants), 15% Asian (10 of 65 participants), 9% subcontinental Indian (six of 65 participants), 6% Latino (four of 65 participants), and 10% other (seven of 65 participants). In a controlled setting, participants completed the DFT after verbal instruction and demonstration of each test, and all participants were video recorded. The four test components included the Up and Walking Test (unassisted sit-to-stand from a chair, walk forward/backward 5 meters [no turn], then unassisted stand-to-sit), Steps Test (ascend three steps, turn, descend three steps), Down and Sitting Test (stand-to-ground, followed by ground-to-stand, with assistance as needed), and Dual-Tasking Test (walk 5 meters forwards and back while counting down from 50 by 2). Tests were timed, and data were collected from video recordings to ensure consistency. Reference values for the DFT were determined via a descriptive analysis, and we calculated the mean, SD, 95% CI, median, and range of time taken to complete each test component, with univariate comparisons between men and women for each component. Linear correlations between age and BMI and test components were studied, and the frequency of verbal and physical pausing and adverse events was noted. RESULTS:The Up and Walking Test was completed in a mean of 15 seconds (95% CI, 14-16), the Steps Test was completed in 6.3 seconds (95% CI, 6.0-6.6), the Down and Sitting Test was completed in 6.0 seconds (95% CI, 5.4-6.6), and the Dual-Tasking Test was performed in 13 seconds (95% CI, 12-14). The length of time it took to complete the Down and Sitting (r = 0.529; p = 0.001), Up and Walking (r = 0.429; p = 0.001), and Steps (r = 0.356; p = 0.014) components increased with as the volunteer's age increased. No correlation was found between age and the time taken to complete the Dual-Tasking Test (r = 0.134; p = 0.289). Similarly, the length of time it took to complete the Down and Sitting (r = 0.372; p = 0.005), Up and Walking (r = 0.289; p = 0.032), and Steps (r = 0.366; p = 0.013) components increased with increasing BMI; no correlation was found between the Dual-Tasking Test's time and BMI (r = 0.078; p = 0.539). CONCLUSIONS:We found that the DFT could be completed by asymptomatic volunteers in approximately 1 minute, although it took longer for older patients and patients with higher BMI. CLINICAL RELEVANCE/CONCLUSIONS:We believe, but did not show, that the DFT might be useful in assessing patients with spinal deformities. The normal values we calculated should be compared in future studies with those of patients before and after undergoing spine surgery to determine whether this test has practical clinical utility. The DFT provides objective metrics to assess function and balance that are easy to obtain, and the test requires no special equipment.

Study Design/UNASSIGNED:Retrospective review of a prospectively collected database. Objective/UNASSIGNED:To predict the occurrence of hospital-acquired conditions (HACs) 30-days postoperatively and to compare predictors of HACs for spine surgery with other common elective surgeries. Methods/UNASSIGNED:Patients ≥18 years undergoing elective spine surgery were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2005 to 2013. Outcome measures included any HACs: superficial or deep surgical site infection (SSI), venous thromboembolism (VTE), urinary tract infection (UTI). Spine surgery patients were compared with those undergoing other common procedures. Random forest followed by multivariable regression analysis was used to determine risk factors for the occurrence of HACs. Results/UNASSIGNED:A total of 90 551 elective spine surgery patients, of whom 3021 (3.3%) developed at least 1 HAC, 1.4% SSI, 1.3% UTI, and 0.8% VTE. The occurrence of HACs for spine patients was predicted with high accuracy (area under the curve [AUC] 77.7%) with the following variables: female sex, baseline functional status, hypertension, history of transient ischemic attack (TIA), quadriplegia, steroid use, preoperative bleeding disorders, American Society of Anesthesiologists (ASA) class, operating room duration, operative time, and level of residency supervision. Functional status and hypertension were HAC predictors for total knee arthroplasty (TKA), bariatric, and cardiothoracic patients. ASA class and operative time were predictors for most surgery cohorts. History of TIA, preoperative bleeding disorders, and steroid use were less predictive for most other common surgical cohorts. Conclusions/UNASSIGNED:Occurrence of HACs after spine surgery can be predicted with demographic, clinical, and surgical factors. Predictors for HACs in surgical spine patients, also common across other surgical groups, include functional status, hypertension, and operative time. Understanding the baseline patient risks for HACs will allow surgeons to become more effective in their patient selection for surgery.

Introduction: Bariatric surgery prior to spine surgery has been shown to reduce medical complication and infection risk in morbidly obese patients. However, long-term impact of irreversible bariatric surgery (bypass, gastrectomy, diversion/switch) on complication rates and outcomes after cervical fusion (CF) for radiculopathy or myelopathy (CR, CM) is unknown.
Method(s): SPARCS was reviewed from 2009-2013 for all obese/morbidly obese patients (Obese). Patients undergoing primary CF for CR or CM were included, and patients undergoing both primary CF and irreversible bariatric surgery were identified. Patients were grouped as obese CF patients with prior bariatric surgery (BAR) or obese CF patients without bariatric surgery (No-BAR), propensity score-matched and analyzed at 90-days and 2-years. Logistic regression was performed to identify predictors for outcomes.
Result(s): 187 patients had <=90-day follow-up (BAR, n=94; No-BAR, n=93); of these, 55 had >=2-year follow-up (n=28/27). Surgical approach was comparable across cohorts. Among 90-day follow-up patients, bariatric-to-CF interval was 2-year for BAR patients. Demographic, LOS, and mortality (0%), were comparable between cohorts. BAR had comparable 90-day rates of individual/overall medical/surgical complication, total complication (3.2 vs 4.3%), readmission (9.6 vs 14%), and revision (9.6 vs 15.1%). Regression revealed BAR did not reduce 90-day adverse outcomes odds. Among patients with 2-year follow-up, bariatric-to-CF interval was 1.4Y for BAR patients; 2-year-readmission was lower for BAR patients (67.9 vs 92.6%). Regression revealed BAR reduced 2-year-readmission odds (OR=0.12, 95% CI: 0.02-0.78), both p<=0.03.
Conclusion(s): Obese/morbidly obese CF patients with CR/CM with prior bariatric surgery incurred comparable outcomes/complications through short-/mid-term follow-up. Primary CF was safe in patients at least 1.4-years after irreversible bariatric surgery.
Copyright

Study Design:Retrospective cohort study. Purpose:The aim of this study was to identify features associated with increased mortality risk in traumatic C2 fractures in the elderly, including measures of comorbidity and frailty. Overview of Literature:C2 fractures in the elderly are of increasing relevance in the setting of an aging global population and have a high mortality rate. Previous analyzes of risk factors for mortality have not included the measures of comorbidity and/or frailty, and no local data have been reported to date. Methods:This study comprises a retrospective review of 70 patients of age >65 years at Waikato Hospital, New Zealand with traumatic C2 fractures identified on computed tomography between 2010 and 2016. Demographic details, medical history, laboratory results on admission, mechanism of injury, and neurological status on presentation were recorded. Medical comorbidities were also detailed allowing calculation of the Charlson Comorbidity Index (CCI) and the modified Frailty Index (mFI). Results:The most common mechanism of injury was a fall from standing height (n=52, 74.3%). Mortality rates were 14.3% (n=10) at day 30, and 35.7% (n=25) at 1 year. Bivariate analysis showed that both CCI and mFI correlated with 1-year mortality rates. Reduced albumin and hemoglobin levels were also associated with 30-day and 1-year mortality rates. Forward stepwise logistic regression models determined CCI and low hemoglobin as predictors of mortality within 30 days, whereas CCI, low albumin, increased age, and female gender predicted mortality at 1 year. Conclusions:The CCI was a useful tool for predicting mortality at 1 year in the patient cohort. Other variables, including common laboratory markers, can also be used for risk stratification, to initiate timely multidisciplinary management, and prognostic counseling for patients and family members.