Faculty Bibliography

BACKGROUND CONTEXT: Age-adjusted alignment targets for adult spinal deformity (ASD) patients have the potential to reduce the incidence of PJK while ensuring optimal HRQL. Previous studies demonstrated the interplay between lumbar lordosis (LL) and thoracic kyphosis (TK) and their relationship with pelvic morphology as measured by the plevic incidence (PI). In clinical practice, reaching this ideal alignment remains challenging as the relationship between lordosis and kyphosis is not clearly elucidated. PURPOSE: This study aimed at developing a pragmatic formula on how much lumbar lordosis is needed based on the patient age, PI and exiting thoracic kyphosis. STUDY DESIGN/SETTING: Multicenter retrospective review of a prospective database. PATIENT SAMPLE: A total of 347 adult spinal deformity patients reaching age-adjusted alignment at 1-year post surgery. OUTCOME MEASURES: Sagittal alignment and internal validation of predictive formula.
METHOD(S): Surgical ASD patients reaching an age-adjusted ideal alignment at one year were identified. Multilinear regressions analysis was used to identify the relationship between regional curvatures (LL &TK) permitting to reach a given global alignment (TPA) based on pelvic incidence.
RESULT(S): The 347 patients included (60 years old, 72% female, BMI 29+/-6.2) had a significant improvement in all sagittal parameters from pre-op to 1Y (p<0.001 except PI). Multilinear regression predicting L1-S1 based on TK, TPA and PI demonstrated excellent results (R2=0.85). Similar results were found when regressions were conducted for each TPA percentile group (R2 ranging from 0.83 to 0.87). Simplification of the coefficients of prediction led to the following equation: LL = PI + 0.3

BACKGROUND CONTEXT: Prior studies have demonstrated potential benefits of adult spinal deformity (ASD) surgery, but less outcomes data exist for operative ASD patients with severe scoliotic curves (thoracic [TH] curve >=75degree, thoracolumbar [TL] curve >=50degree, or lumbar [LL] curve >=50degree). Also, the surgical complication profile is less clear for this subset of patients with severe scoliotic deformity and warrants focused investigation. PURPOSE: The objective of the current study was to assess treatment outcomes and complication rates associated with ASD surgery in patients with severe scoliosis. STUDY DESIGN/SETTING: Retrospective review of a prospectively collected multicenter consecutive case registry PATIENT SAMPLE: Enrollment required: age >=18 yrs, scoliosis >=20degree, sagittal vertical axis (SVA) >=5cm, pelvic tilt >=25degree, and/or thoracic kyphosis >=60degree. OUTCOME MEASURES: Standard coronal and sagittal spinopelvic deformity measurements and health-related quality of life (HRQL) outcomes, which included Oswestry Disability Index (ODI), Short Form-36 (SF-36) scores, and Scoliosis Research Society-22 (SRS-22) scores.
METHOD(S): Using a prospective multicenter database, we identified surgically treated ASD patients with severe scoliosis (TH Cobb >=75degree or TL/LL Cobb >=50degree) and minimum 2-yr follow-up. Demographic data, surgical characteristics, radiographic alignment measurements, HRQL outcomes and associated complications were analyzed.
RESULT(S): Of 178 patients, 146 (82%, mean age 54 yrs, 92% women, 88 TL, 50 LL, 8 TH) had minimum 2-yr follow-up (mean=3.1 yrs). Almost 30% had prior spine fusion, 6% were active or past smokers, 16% had osteoporosis and 77% had at least 1 comorbidity. Surgical details included: posterior-only (58%) or anterior-posterior approach (42%), SPO (65%), 3CO (14%), TLIF (23%), ALIF (37%), sacropelvic fixation (76%), upper thoracic UIV (64%) and mean posterior fusion length of 13.2 levels. Postoperative coronal alignment improved significantly for all patients (global coronal alignment 3.8 to 2.8 cm, p< 0.001; TH Cobb 38degree to 24degree, p<0.001; TL Cobb 61degree to 30degree, p<0.001; LL Cobb 50degree to 24degree, p<0.001; Fractional Cobb 20degree to 7degree, p<0.001). Overall sagittal alignment also improved significantly (p<0.05), most notably for severe lumbar curves (C7-S1 SVA 6.7 to 2.5 cm, p<0.001; PI-LL 18degreeto 3degree, p<0.001). Overall HRQL improved significantly, including ODI (39 to 26, p<0.001), SF-36 PCS (35 to 41, p<0.001) and SRS-22r (2.9 to 3.8, p<0.001). A total of 191 complications were reported (92 minor/99 major), and 94 (64%) patients had at least one complication. The most common complications included dural tear (12%), pleural effusion (12%), rod fracture (11%), radiculopathy (8%) and proximal junctional kyphosis (7%). 34 reoperations were performed in 27 (18%) patients, with most common indications of rod fracture/pseudarthrosis (8), deep wound infection (6) and neurological deficit (5).
CONCLUSION(S): Surgery for severe adult scoliosis is associated with significant improvement in radiographic alignment and HRQL measures. Although associated complication rates are high, these appear to be comparable to reports of less severe scoliosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Frailty is an increasingly recognized characteristic that has been validated across many studies as influencing operative risk. Utilization of frailty indices can allow for its identification of which spine patients may be too high risk for surgical intervention. This may be especially useful when it comes to surgeries that are minimally invasive and are supposed to have decrease perioperative outcomes. PURPOSE: Identify MIS techniques effects in postoperative outcomes in TLIF patients. STUDY DESIGN/SETTING: Retrospective review of a prospective database. PATIENT SAMPLE: TLIF spine patients. OUTCOME MEASURES: Complications, length of stay (LOS), estimated blood loss (EBL).
METHOD(S): Pts that underwent a lumbar spine procedure in a single-center Comprehensive Spine Quality Database. Pts were stratified based on procedural approach (Open [OP] and Minimally invasive Surgery [MIS]). Frailty was then calculated for each resultant group by using 30 variables with a validated method. Based on these scores, pts were categorized no frailty [NF]: <0.09, frail [F]: 0.09-0.18, and severe frailty [SF] >0.18. Groups were then controlled for surgical invasiveness. Chi-squared tests identified the relationship between complications and length of stay among various frailty states given surgical approach (OP vs MIS). These patients were propensity score matched for levels fused. Hospital acquired complications (HACs) were identified based on frailty groups through the use of chi-squared and t-tests for other surgical factors. A logistic regression analysis identified the association between frailty status and surgical, regarding postoperative (postop) outcomes.
RESULT(S): A total of 1,300 TLIF spine patients were isolated (59yrs, 29.3kg/m2). After PSM for levels fused, there were 338 pts for both MIS and OP. MIS pts were older (56.1 vs 53.3; p<0.05) than Op pts and had similar BMI's (29.1 vs 29.7; respectively). However, OP received more posterior approaches and less anterior approaches than MIS pts (p<0.05). By surgical factors: MIS and OP patients had similar LOS (3 vs 2.9days) and EBL (282.8 vs 251.5cc) but differed by Op time (195.7 vs 247.1; p<0.05) respectively. Further breakdown by frailty displayed statistical significance between MIS and OP patients with MIS pts having more F (16% vs 12%) and SF pts (4.3% vs 1.9%) than OP (all p<0.05). FMIS patients had lower postop neurologic complications as compared to FOP pts (4.63% vs 14.8%). However, SFMIS patiens had more post-operative complications than SFOP pts (55.2% vs 23.1%) and increased a pt's likelihood of being SFMIS by 5.4x's (all p<0.05).
CONCLUSION(S): This study displays that when frailty status is taken into account, TLIF MIS patients benefit from this procedure type when analyzed against neurologic complications. However, these patients were seen to suffer more from postop complications but did not differ on any other specific complications or surgical variables. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Traditionally, adult spinal deformity (ASD) has been treated with long segment fusions with the goal of restoring sagittal and coronal alignment. Long segment fusions can be associated with high rates of complications and morbidity. Some patients are reluctant to undergo large procedures. Others have comorbidities excluding them as good surgical candidates for long fusions. PURPOSE: To compare baseline and postoperative HRQL and radiographic outcomes and revisions and complications in small vs longer fusions for ASD. STUDY DESIGN/SETTING: Retrospective analysis of a prospective, multicenter database PATIENT SAMPLE: Surgical ASD patients OUTCOME MEASURES: ODI, SF36-PCS, SRS22, NRS back and leg pain.
METHOD(S): A prospective database of operative ASD patients who completed two year follow up was analyzed. Prior thoracolumbar fusions were excluded. Patients were divided into short fusions (SF: 3 levels) and long fusions (LF: 36 levels). LF and SF patients were compared in baseline alignment. Propensity matching (PSM) controlling for baseline alignment (TPA and maximum coronal cobb) was performed to compare SF and LF in HRQL improvement, postop alignment and complications. Subanalysis of SF identified which patients were more likely to have successful surgery. The level of significance was p<0.05.
RESULT(S): A total of 298 patients met inclusion criteria (SF n=20, mean levels fused 2.13; LF n=275, mean fusion levels 12.33). Prior to PSM, LF had greater PT, coronal cobb, and TPA. Following PSM, LF had better improvements in PILL (20.8 vs 3.37), PT (8.57 vs 0.21), TPA (8.68 vs 2.07), and coronal cobb (17.3 vs 5.33) all p<0.005. There were no differences in 2y HROL improvement, satisfaction or reoperations. SF had fewer complications (OR 0.15, p=0.018). In the SF group, the deformities were 15% sagittal, 40% coronal, and 45% combined. In the sagittal group, 67% of surgery aimed at deformity correction but 67% of these required revision long fusion surgery. In the coronal group, 38% of surgery aimed at deformity correction with no revisions. In the combined group. 67% of surgery aimed at deformity correction but 11% of these required revision long fusion surgery.
CONCLUSION(S): This study shows that a more limited fusion could be an alternative to the more traditional long segment fusion in carefully selected patients with adult spinal deformity since there were fewer complications but similar short-term (2-year) satisfaction rates and HRQL improvements. Patients undergoing long fusions had better improvements in alignment. The majority of sagittal only deformities undergoing short fusions required revision surgery. The durability of short fusions in the setting of ASD needs to be investigated with long term studies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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Background/UNASSIGNED:Changes in spinopelvic and lower extremity alignment between standing and relaxed sitting have important clinical implications with regard to stability of total hip arthroplasty. This study aimed to analyze the effect of body mass index (BMI) on lumbopelvic alignment and motion at the hip joint. Methods/UNASSIGNED:A retrospective review of patients who underwent full-body stereoradiographs in standing and relaxed sitting for total hip arthroplasty planning was conducted. Spinopelvic parameters measured included spinopelvic tilt (SPT), pelvic incidence (PI), lumbar lordosis (LL), PI minus LL (PI-LL), proximal femoral shaft angle (PFSA), and standing-to-sitting hip range of motion. Propensity score matching controlled for age, gender, PI, and hip ostoarthritis grade. Patients were stratified into normal (NORMAL; BMI, 18.5-24.9), overweight (OW; 25.0-29.9), and obese (OB; 30.0-34.9) groups. Alignment parameters were compared using one-way analysis of variance. Results/UNASSIGNED:< .001). Conclusions/UNASSIGNED:Significant differences in sitting and standing-to-sitting change in lumbopelvic alignment based on BMI suggest obese patients recruit more posterior spinopelvic tilt when sitting to compensate for soft-tissue impingement that occurs anterior to the hip joint and limiting hip flexion.

BACKGROUND CONTEXT: Lateral lumbar interbody fusion (LLIF) provides indirect decompression of the neural elements while minimizing the potential vascular complications associated with anterior lumbar interbody fusion (ALIF). Posterior fixation may be applied through various techniques such as conventional minimally invasive surgery (CMIS), requiring the patient to be repositioned prone to provide access to both pedicles. Conversely, robot-assisted navigation (RAN) of pedicle screws can be utilized from a single position without flipping the patient. RAN is theorized to reduce patient surgical time, radiation, and blood loss due to positioning and workflow effects. PURPOSE: To evaluate the effect of robot-assisted navigation in comparison to CMIS methods in terms of surgical time, radiation exposure, and pedicle screw accuracy. STUDY DESIGN/SETTING: Cadaveric study. PATIENT SAMPLE: N/A OUTCOME MEASURES: N/A METHODS: Twelve unembalmed human torsos were implanted with 2-level static LLIF cages, followed by posterior bilateral pedicle screw fixation using either CMIS (n=6) or RAN (n=6). Preoperative computed tomography (CT) RAN workflow utilized CT scans of the specimen taken offsite and transferred to the robotic system during setup. Screw planning was performed using these CT scans, and then was merged with intraoperative fluoroscopy. Surgical times, surgeon radiation exposure, and screw accuracy were measured. Patient flip time from a consecutive patient series was included.
RESULT(S): Significant differences in surgical times and radiation dosages were found between groups. Surgical time for preoperative RAN and CMIS was 64.7 min+/-4.1 min and 123.0 min+/-13.7 min, respectively. Time per screw for RAN and CMIS workflows was 2.7+/-0.6 min and 4.3+/-1.3 min, respectively. RAN was significantly different for total operative time and time per screw in comparison to CMIS (p<0.05). Radiation dosages and times were separated into interbody and posterior fixation procedures separately, and sorted by imaging workflow. RAN and CMIS radiation dosages during posterior fixation were 0.4+/-0.2 rad and 2.7+/-1.6, respectively (p<0.05). Screw accuracy was as follows: CMIS resulted in 4 breaches (11% breach rate), while RAN resulted in a single breach (3% breach rate).
CONCLUSION(S): Significant differences were found in both surgical time and radiation exposure between CMIS and RAN, with RAN resulting in shorter surgical times and less radiation exposure to the surgeon than CMIS. Consideration should be given to single-position LLIF procedures that utilize RAN to instrument the spine with bilateral pedicle screws. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Thoracolumbar malalignment is often seen in patients presenting with cervical deformities. For operative cervical deformity (CD) patients, it is unknown whether certain thoracolumbar parameters play a large role in poor outcomes (complications, distal junctional kyphosis, reoperation) and whether addressment of such parameters is warranted. PURPOSE: To investigate the impact of cervical to thoracolumbar ratios on poor outcomes in CD corrective surgery. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: 110 CD patients. OUTCOME MEASURES: Radiographic parameters: regionally and globally; complications; distal junctional kyphosis (DJK); reoperations; health-related quality-of-life (HRQLs): NDI, EQ5D, mJOA.
METHOD(S): Included: surgical CD pts (C2-C7 Cobb >10degree, CL>10degree, cSVA >4cm, or CBVA >25degree) with full baseline and 1-year data. Patients were assessed for ratios of preop cervical and global parameters including: C2 slope/T1 slope, TS-CL/PI-LL, cSVA/SVA. Deformity classification ratios of cervical (Ames-ISSG) to spinopelvic (SRS-Schwab) were investigated: cSVA modifier/SVA modifier, TS-CL modifier/PI-LL modifier. Cervical to thoracic ratios included C2-C7 lordosis/T4-T12 kyphosis. Correlations assessed the relationship between ratios and poor outcome (major complication, reoperation, HRQL decline or failure to meet MCID). Decision tree analysis through multiple iterations of multivariate regressions assessed cut-offs for ratios for acquiring suboptimal outcomes.
RESULT(S): A total of 110 cervical deformity patients were included in the present analysis (61.5+/-9.9 years, 66% female, 28.8+/-7.5 kg/m2). By approach, 18.2% underwent anterior-only procedures, 46.4% posterior, and 35.4% combined. Average levels fused: 7.7+/-3.7 levels (anterior: 3.5, posterior: 8.5). The average preoperative radiographic ratios assessed included a C2 slope/T1 slope 1.56, TS-CL/PI-LL of 11.1, cSVA/SVA of 5.4, CL/TK of 0.26. Ames-ISSG and SRS-Schwab modifier ratios of cSVA/SVA 0.1 and TS-CL/PI-LL of 0.35. Pearson correlations demonstrated a significant relationship between major complications and the baseline TS-CL/PI-LL with a cutoff of >12.72 (p=0.034), >0.482 Ames TS-CL/Schwab PI-LL modifiers (p=0.019), and the CL/TK ratios (>0.814, p=0.050). Reoperation had a significant correlation with the TS-CL/PI-LL (>5.819, p=0.009) and the cSVA/SVA (>3.79, p=0.002) ratios. Postoperative DJK had a correlation with the C2 slope/T1 slope (>1.59, p=0.017) and CL/TK (>0.692, p=0.0629) ratios. Not meeting MCID for NDI correlated with the CL/TK ratio (>1.402, p=0.016) and not meeting MCID for EQ5D correlated with the Ames TS-CL/Schwab PI-LL (>0.564, p=0.010).
CONCLUSION(S): Consideration of the ratio of distal regional to global alignment is a critical determinant of outcomes in cervical deformity corrective surgery. Several key ratios of cervical to global alignment were found to correlate with the occurrence of suboptimal realignment parameters, or poor clinical outcomes. A larger cervical lordosis to thoracic kyphosis was most representative of this risk, which predicted a complication, DJK, and not meeting MCID for NDI. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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STUDY DESIGN/UNASSIGNED:Retrospective cohort study of prospective patients undergoing minimally invasive lumbar fusion at a single academic institution. OBJECTIVE/UNASSIGNED:To assess differences in perioperative outcomes between primary and revision MIS (minimally invasive surgical) lumbar interbody fusion patients and compare with those undergoing corresponding open procedures. METHODS/UNASSIGNED:Patients ≥18 years old undergoing lumbar interbody fusion were grouped by surgical technique: MIS or open. Patients within each group were propensity score matched for comorbidities and levels fused. Patient demographics, surgical factors, and perioperative complication incidences were compared between primary and revision cases using means comparison tests, as appropriate. RESULTS/UNASSIGNED:< .05). CONCLUSIONS/UNASSIGNED:Clinical outcomes of revision MIS lumbar interbody fusion were similar to those of primary surgery. Additionally, MIS techniques were associated with less EBL, shorter LOS, and fewer perioperative complications than corresponding open revisions.

BACKGROUND CONTEXT/BACKGROUND:Patients with severe cervical deformity (CD) often have profound deficits in numerous activities of daily living. The association between health status and post-operative radiographic goals is difficult to quantify. PURPOSE/OBJECTIVE:We aimed to investigate the radiographic characteristics of patients who achieved optimal health related quality of life scores following surgery for CD. STUDY DESIGN/METHODS:We performed a retrospective review of a prospectively collected database of patients with spinal deformity. PATIENT SAMPLE/METHODS:One hundred and fifty-three patients with cervical deformity OUTCOME MEASURES: Common health-related quality of life scores (HRQOLs) measurements were taken for patients treated operatively for cervical deformity including neck disability index (NDI), modified Japanese Orthopaedic Association scale (mJOA) for myelopathy and numeric rating scale for neck pain (NRS-neck), METHODS: Surgical patients with severe (can you define severe?) CD were isolated based upon a previously presented discriminant analysis which outlined a combination of preoperative cervical sagittal vertical axis (cSVA), T1 slope, maximum focal kyphosis in extension, C2 slope in extension, and number of kyphotic levels in extension. Those with available preoperative and 1-year postoperative HRQL data were included. Based on a previous study, patients were grouped into 3 distinct sagittal morphotypes of CD: focal deformity (FD), flatneck (FN=large TS-CL and lack of compensation), or cervicothoracic (CT). Post-operative outcomes were defined as "good" if a patient had ≥2 of the 3 following criteria (1) NDI <20 or meeting MCID, (2) mild myelopathy (mJOA≥14), and (3) NRS-Neck ≤5 or improved by ≥2 points from baseline. Within each distinct deformity group, patients with good outcomes were compared to those with poor outcomes (i.e. not meeting the criteria for good) for differences in demographics, HRQL scores, and alignment, via Chi-squared or student's t-tests. RESULTS:Overall, 83 of 153 patients met the criteria of severe CD and 40 patients had complete 1-year follow-up of clinical/radiographic data. Patient breakdown by deformity pattern was: CT (N=13), FN (N=17), and FD (N=17), with 7 patients meeting criteria for both FD and FN deformities. Within the FD cohort, maximal focal kyphosis (i.e. kyphosis at one level) was better corrected in patients with a "good" outcome (p = 0.03). In the FN cohort, patients with "good" outcomes presented pre-operatively with worse horizontal gaze (McGregor Slope 21° vs 6°, p=0.061) and cSVA (72mm vs 60mm, p=0.030). "Good" outcome FN patients showed significantly greater postop correction of horizontal gaze (-25° vs -5°, p = 0.031). In the CT cohort, patients with "good" outcomes had superior global alignment both pre- (SVA: -17mm vs 108mm, p <0.001) and post-operatively (50mm vs 145mm, p=0.001). CT patients with "good" outcomes also had better postop cervical alignment (cSVA 35mm vs 49mm, p=0.030), and less kyphotic segments during extension (p=0.011). In the FD cohort, there were no differences between "good" and "poor" outcomes patients in preoperative alignment; however, "good" outcome patients showed superior changes in postoperative focal kyphosis (-2° vs 5°, p=0.030). Within all three deformity pattern categories, there were no differences between "good" and "poor" outcome patients with respect to demographics or surgical parameters (levels fused, surgical approach, decompression, osteotomy, all p>0.050). CONCLUSIONS:The results of this study show each CD patient's unique deformity must be carefully examined in order to determine the appropriate alignment goals to achieve optimal HRQOLs. In particular, the recognition of the sagittal morphotype can help assist surgeons to aim for specific alignment goals for CT, FN and FD. Distinct deformity specific intra-operative goals include obtaining proper sagittal global/cervical alignment for cervicothoracic patients, correcting maximal focal kyphosis in focal deformity patients, and correcting horizontal gaze for flatneck patients.

BACKGROUND:As of May 4, 2020, the coronavirus disease 2019 (COVID-19) pandemic has affected >3.5 million people and touched every inhabited continent. Accordingly, it has stressed health systems worldwide, leading to the cancellation of elective surgical cases and discussions regarding health care resource rationing. It is expected that rationing of surgical resources will continue even after the pandemic peak and may recur with future pandemics, creating a need for a means of triaging patients for emergent and elective spine surgery. METHODS:Using a modified Delphi technique, a cohort of 16 fellowship-trained spine surgeons from 10 academic medical centers constructed a scoring system for the triage and prioritization of emergent and elective spine surgeries. Three separate rounds of videoconferencing and written correspondence were used to reach a final scoring system. Sixteen test cases were used to optimize the scoring system so that it could categorize cases as requiring emergent, urgent, high-priority elective, or low-priority elective scheduling. RESULTS:The devised scoring system included 8 independent components: neurologic status, underlying spine stability, presentation of a high-risk postoperative complication, patient medical comorbidities, expected hospital course, expected discharge disposition, facility resource limitations, and local disease burden. The resultant calculator was deployed as a freely available Web-based calculator (https://jhuspine3.shinyapps.io/SpineUrgencyCalculator/). CONCLUSIONS:We present the first quantitative urgency scoring system for the triage and prioritizing of spine surgery cases in resource-limited settings. We believe that our scoring system, although not all encompassing, has potential value as a guide for triaging spine surgical cases during the COVID pandemic and post-COVID period.