Faculty Bibliography

BACKGROUND CONTEXT/BACKGROUND:Correcting sagittal malalignment in adult spinal deformity (ASD) is a challenging task, often requiring complex surgical interventions like pedicle subtraction osteotomies (PSOs). Different types of three-column osteotomies (3COs), including Schwab 3, Schwab 4, Schwab 4 with interbody cages, and the "sandwich" technique, aim to optimize alignment and fusion outcomes. The role of interbody cages in enhancing fusion and segmental correction remains unclear. PURPOSE/OBJECTIVE:This study aimed to compare outcomes among these 4 3CO techniques, evaluating the impact of cage use at the osteotomy site on postoperative radiographic imaging and clinical outcomes. STUDY DESIGN/SETTING/METHODS:This is a multicenter retrospective study utilizing data from a prospective multicenter database of patients undergoing complex ASD surgery. PATIENT SAMPLE/METHODS:Ninety-seven patients who underwent 1 of 4 3CO techniques for thoracolumbar ASD correction with at least 2 years of follow-up were included. The sample consisted of 29 patients who underwent Schwab 3 osteotomy, 20 Schwab 4, 28 Schwab 4 with interbody cages, and 20 who underwent "sandwich" osteotomy. OUTCOME MEASURES/METHODS:The Scoliosis Research Society-22 revised (SRS22r) questionnaire evaluating pain, activity, appearance, mental health, and satisfaction was used to evaluate patient reported outcomes and radiographic measures including segmental lordosis and fusion rates determined by 3 blinded reviewers were used to evaluate physiologic outcomes. METHODS:This study analyzed demographic data, radiographic outcomes, patient-reported outcomes, complications, and fusion rates over a 2-year follow-up period. Fusion status was determined via serial radiographs and evaluated independently by 3 blinded reviewers. Univariate and multivariate statistical analyses were performed to assess differences among the groups and the impact of interbody cage use on outcomes. RESULTS:Patients undergoing "sandwich" osteotomy exhibited worse preoperative leg pain scores and lower SRS22r activity (p=.015), appearance (p=.007), and mental health domain scores (p=.0015). No differences in complications were found among groups (p>.05). Patients who underwent osteotomy with a cage were more likely to have had previous spine fusion (91.7% vs. 71.4%, p=.010). Additionally, these patients had lower preoperative SRS22r mental domain (2.9±1 vs. 3.5±1, p=.009), satisfaction (2.3±1 vs. 2.7±1.2, p=.034), and SRS22r total scores (2.3±0.6 vs. 2.6±0.6, p=.0026) but demonstrated the greatest improvement in the mental health domain (0.9±0.7 vs. 0.3±0.9, p=.002). Cage use was associated with a larger mean change in segmental lordosis at the osteotomy site (32.9±9.6 vs. 28.7±9.5, p=.038). Fusion rates were significantly higher in the cage group (79.2% vs. 55.1%, p=.0012). Regression analysis identified cage use as an independent predictor for fusion (odds ratio, 3.338; 95% confidence interval, 1.108-10.054, p=.032). CONCLUSIONS:Interbody cage use at the osteotomy site during 3COs for ASD correction was associated with improved fusion rates and greater segmental lordosis without increasing complication rates. Incorporating cages may provide enhanced alignment and fusion outcomes in complex ASD surgeries.

INTRODUCTION/BACKGROUND:With the rapid increase in the use of robotic-assisted spine surgery (RASS), reports describing complications have inevitably emerged. This study builds on previous work done to identify, characterize, and classify potential sources of error in spine surgery performed with enabling technology in the operating room. The goal of this study is to leverage expert opinion to develop a set of best practice guidelines that can be employed to minimize complications and optimize patient safety, specifically as it relates to RASS. METHODS:After assembling a group of attending spine surgeons experienced in the use of RASS across the country, formal consensus regarding the best practices was developed using the Delphi method and nominal group technique. After a review of the relevant literature and evidence, an initial survey of study group members (n=12) helped frame potential areas for investigation. Statements were subsequently edited, removed, or elaborated upon during four iterative rounds of live discussion with the opportunity for panelists to propose new guidelines at any point in the process. Respondents were able to suggest modifications and refine the statements until consensus, defined as ≥ 80% agreement, was achieved. RESULTS:After a three-round iterative survey and video conference Delphi process, followed by an in-person meeting at the Summit for Safety in Spine Surgery, consensus was achieved on 27 best practice guideline statements. This BPG had the key focus areas of 1) general protocols, 2) screw planning/execution, 3) optimization of surgical technique, and 4) areas for robotic improvement. (available at https://safetyinspinesurgery.com/ ). CONCLUSION/CONCLUSIONS:This work provides expert insight into the best practices for minimizing errors in RASS with the presentation of 27 recommendations that can serve to reduce practice variability, optimize safety, and guide future research.

BACKGROUND/UNASSIGNED:open or minimally invasive (MIS) laminectomy using the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) database. METHODS/UNASSIGNED:Using the ACS-NSQIP database from 2017 to 2022, Current Procedural Terminology (CPT) code of 63030 or 62380 were used to filter the dataset between open/tubular retractor-based and endoscopic single-level lumbar decompression cases, respectively. Overall, as collected, the endoscopic group consisted of 336 patients and the non-endoscopic group had 55,111 patients. The groups were compared to evaluate the patient characteristics and adverse events within 30 days after their operation. Outcome measures compared were operative time, length of stay (days), adverse outcomes [superficial infection, deep infection, organ/space infection, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, ventilator >48 hours, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke/cerebrovascular accident (CVA) accident, cardiac arrest, myocardial infarction, blood transfusion, deep vein thrombosis (DVT), sepsis, and septic shock], 30-day readmission, return to operating room (OR). RESULTS/UNASSIGNED:4.8%, P=0.01), with significantly lower rate of blood transfusions (P<0.05) compared to the non-endoscopic group. CONCLUSIONS/UNASSIGNED:Patients who underwent endoscopic lumbar decompression demonstrated a significantly lower rate of total adverse events and significantly lower rate of blood transfusions compared to their counterparts. This data from the ACS-NSQIP supports the reported benefits of endoscopic technique in the current literature. As endoscopic surgery becomes more widely utilized throughout the United States, more data will become available for further studies.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The concept of upper cervical (C0-C2) extension reserve (ER) capacity, ER relaxation, and their impact on outcomes following surgical correction of adult cervical deformity (ACD) has not been extensively studied. We aimed to evaluate the impact of upper cervical ER on postoperative disability and outcomes. METHODS:Patients with ACD, from a retrospective cohort study of a prospectively collected multicenter database, undergoing subaxial cervical fusion with 2-year (2Y) follow-up data were included. ER was defined as: ΔC0-C2 sagittal Cobb angle between neutral and extension. Relaxation of ER was defined as the ER mean in those that met all ideal thresholds in radiographic parameters for Passias et al CD modifiers. We used multivariable logistic regression to adjust for confounding, with conditional inference tree approaches used to determine thresholds that affect postoperative ER resolution on patient-reported outcomes. RESULTS:A total of 108 patients with ACD met inclusion. Preoperative C0-C2 ER was 8.7° ± 9.0°, and at last follow-up was 10.3° ± 11.1°. Preoperatively 29% of the cohort had adequate ER, whereas 60% had improved ER postoperatively, with 50% achieving adequate ER by 2Y. Lower ER correlated with greater CD (P < .05). Preoperatively, greater ER had lower Neck Disability Index (P < .001). Controlled analysis found improved ER to have a greater likelihood of achieving Neck Disability Index minimum clinically important difference (odds ratio 6.94, [1.378-34.961], P = .019). In those with inadequate ER at baseline, the preoperative C2-C7 of < -18° and T1 slope-cervical Lordosis mismatch of >59° for T1 slope-cervical Lordosis mismatch was predictive of ER resolution. In those with preoperative C2-C7 >-18°, a T1PA of >13° was predictive of postoperative return of ER (all P < .05). Surgical correction of C2-C7 by > 16° from baseline was found to be predictive of ER return. CONCLUSION/CONCLUSIONS:Increased preoperative use of the C0-C2 ER in CD was associated with worse baseline regional and global alignment and adversely affected health-related measures. Most of the patients had ER relaxation postoperatively. In those who didn't, however, there was a decreased likelihood of achieving satisfactory outcomes.

STUDY DESIGN/METHODS:Retrospective analysis of prospectively-collected data. OBJECTIVE:This study aims to define clinically relevant blood loss in adult spinal deformity (ASD) surgery. BACKGROUND:Current definitions of excessive blood loss following spine surgery are highly variable and may be suboptimal in predicting adverse events (AE). METHODS:Adults undergoing complex ASD surgery were included. Estimated blood loss (EBL) was extracted for investigation, and estimated blood volume loss (EBVL) was calculated by dividing EBL by the preoperative blood volume utilizing Nadler's formula. LASSO regression was performed to identify five variables from demographic and peri-operative parameters. Logistic regression was subsequently performed to generate a receiver operating characteristics (ROC) curve and estimate an optimal threshold for EBL and EBVL. Finally, the proportion of patients with AE plotted against EBL and EBVL to confirm the identified thresholds. RESULTS:In total 552 patients were included with a mean age of 60.7±15.1 years, 68% females, mean CCI was 1.0±1.6, and 22% experienced AEs. LASSO regression identified ASA score, baseline hypertension, preoperative albumin, and use of intra-operative crystalloids as the top predictors of an AE, in addition to EBL/EBVL. Logistic regression resulted in ROC curve which was used to identify a cut-off of 2.3 liters of EBL and 42% for EBVL. Patients exceeding these thresholds had AE rates of 36% (odds-ratio: 2.1, 95% CI [1.2-3.6]) and 31% (odds-ratio: 1.7, 95% CI [1.1-2.8]), compared to 21% for those below the thresholds of EBL and EBVL, respectively. CONCLUSION/CONCLUSIONS:In complex ASD surgery, intraoperative EBL of 2.3 liters and an EBVL of 42% are associated with clinically-significant AEs. These thresholds may be useful in guiding preoperative-patient-counseling, healthcare system quality initiatives, and clinical perioperative bloodloss management strategies in patients undergoing complex spine surgery. Additionally, similar methodology could be performed in other specialties to establish procedure-specific clinically-relevant bloodloss thresholds.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The spectrum of patients requiring adult spinal deformity (ASD) surgery is highly variable in baseline (BL) risk such as age, frailty, and deformity severity. Although improvements have been realized in ASD surgery over the past decade, it is unknown whether these carry over to high-risk patients. We aim to determine temporal differences in outcomes at 2 years after ASD surgery in patients stratified by BL risk. METHODS:Patients ≥18 years with complete pre- (BL) and 2-year (2Y) postoperative data from 2009 to 2018 were categorized as having undergone surgery from 2009 to 2013 [early] or from 2014 to 2018 [late]. High-risk [HR] patients met ≥2 of the criteria: (1) ++ BL pelvic incidence and lumbar lordosis or SVA by Scoliosis Research Society (SRS)-Schwab criteria, (2) elderly [≥70 years], (3) severe BL frailty, (4) high Charlson comorbidity index, (5) undergoing 3-column osteotomy, and (6) fusion of >12 levels, or >7 levels for elderly patients. Demographics, clinical outcomes, radiographic alignment targets, and complication rates were assessed by time period for high-risk patients. RESULTS:Of the 725 patients included, 52% (n = 377) were identified as HR. 47% (n = 338) had surgery pre-2014 [early], and 53% (n = 387) underwent surgery in 2014 or later [late]. There was a higher proportion of HR patients in Late group (56% vs 48%). Analysis by early/late status showed no significant differences in achieving improved radiographic alignment by SRS-Schwab, age-adjusted alignment goals, or global alignment and proportion proportionality by 2Y (all P > .05). Late/HR patients had significantly less poor clinical outcomes per SRS and Oswestry Disability Index (both P < .01). Late/HR patients had fewer complications (63% vs 74%, P = .025), reoperations (17% vs 30%, P = .002), and surgical infections (0.9% vs 4.3%, P = .031). Late/HR patients had lower rates of early proximal junctional kyphosis (10% vs 17%, P = .041) and proximal junctional failure (11% vs 22%, P = .003). CONCLUSION/CONCLUSIONS:Despite operating on more high-risk patients between 2014 and 2018, surgeons effectively reduced rates of complications, mechanical failures, and reoperations, while simultaneously improving health-related quality of life.

PURPOSE/OBJECTIVE:Clinical trials have studied the effects of curve magnitude and flexibility, age, and skeletal immaturity on the outcomes of VBT. No studies have assessed the effect of Lenke curve type on the outcomes of VBT. This study compares outcomes in patients who underwent VBT with Lenke type 1, 3, 5, and 6 curves. METHODS:Single center retrospective review of patients undergoing mini-open thoracoscopic-assisted two row vertebral body tethering (2RVBT) for the correction of AIS with a minimum 2-year follow-up were included. Patients were grouped by Lenke type, which yielded 4 groups; types 1, 3, 5, or 6. Analysis included preoperative demographic parameters, as well as radiographic and clinical outcome measures. RESULTS:156 2RVBT (Lenke 1, N = 61; Lenke 3, N = 35; Lenke 5, N = 37; Lenke 6, N = 23) patients met inclusion criteria. The mean preoperative apex Cobb angle in the Lenke type 1, 3, 5, and 6 groups were 50.2 ± 9.1, 50.5 ± 10.1, 45.0 ± 8.6, and 49.0 ± 10.8, respectively. This corrected to 21.2 ± 10.2, 19.2 ± 8.5, 13.6 ± 7.2, 18.5 ± 8.3 in Lenke type 1, 3, 5, and 6 groups, respectively, demonstrating that Lenke type 5 saw greatest correction following 2RVBT. With regards to revision recommendation following tether breakage, Lenke type 3 curves were most frequently indicated for fusion, whereas Lenke type 1 curves were most frequently not indicated for revision surgery. CONCLUSION/CONCLUSIONS:Lenke type 5 curves are the most amenable to correction via 2RVBT, as evident by their lower post-operative apex Cobb angles and lowest rate of recommendation for revision to posterior spinal fusion.

STUDY DESIGN/METHODS:Retrospective analysis of prospectively collected data. OBJECTIVE:This study evaluates the impact of knee osteoarthritis (OA) and knee arthroplasty on alignments and patient-reported outcomes measures (PROMS) of patients undergoing adult spinal deformity (ASD) corrective surgery. BACKGROUND:The relationship between knee OA and spinal alignment in patients with ASD is incompletely understood. It is also unknown how patients with knee arthroplasty and ASD compare to ASD patients with native knees. METHODS:Baseline full-body radiographs were used, and hip and knee OA were graded by two independent reviewers using the KL classification. Spinopelvic parameters and PROMs were compared across the different knee OA groups and compared between patients with knee replacement and native knees. RESULTS:199 patients with bilateral non severe OA (G1), 31 patients with unilateral severe knee OA (G2), and 60 patients with bilateral severe knee OA (G3). Patients with severe knee OA presented with worse spinopelvic parameters. However, after multivariable regression analysis controlling for age, frailty, PI, T1PA, knee OA was an independent predictor of knee flexion (G1:-0.02±7.3, G2: 7.8±9.4, G3: 4.5±8.7, P<0.001), and ankle dorsiflexion (G1: 2.3±4.0, G2: 6.6±4.5, G3: 5.1±4.1, P<0.001). There was no difference in PROMs (P>0.05). Secondary analysis included 96 patients: 48 patients (50%) with non-severe knee OA, and 48 patients (50%) with knee replacement. There was no difference in radiographic parameters or PROMs between the groups. CONCLUSION/CONCLUSIONS:In this study of complex ASD patients, patients with worse spinal deformity were more likely to have concomitant knee OA. Knee OA was shown to be a predictor of knee flexion and ankle dorsiflexion angles, but was not associated with worse PROMs in this study population. Patients with knee arthroplasty, however, had comparable spinal alignment and PROMs relative to those with mild OA.

BACKGROUND AND OBJECTIVES/OBJECTIVE:To investigate the cost-effectiveness and impact of prophylactic techniques on the development of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the context of postoperative alignment. METHODS:Adult spinal deformity patients with fusion to pelvis and 2-year data were included. Patients receiving PJK prophylaxis (hook, tether, cement, minimally-invasive surgery approach) were compared to those who did not. These cohorts were further stratified into "Matched" and "Unmatched" groups based on achievement of age-adjusted alignment criteria. Costs were calculated using the Diagnosis-Related Group costs accounting for PJK prophylaxis, postoperative complications, outpatient health care encounters, revisions, and medical-related readmissions. Quality-adjusted life years were calculated using Short Form-36 converted to Short-Form Six-Dimension (SF-6D) and used an annual 3% discount rate. Multivariate analysis controlling for age, sex, levels fused, and baseline deformity severity assessed outcomes of developing PJK/PJF if matched and/or with use of PJK prophylaxis. RESULTS:A total of 738 adult spinal deformity patients met inclusion criteria (age: 63.9 ± 9.9, body mass index: 28.5 ± 5.7, Charlson comorbidity index: 2.0 ± 1.7). Multivariate analysis revealed patients corrected to age-adjusted criteria postoperatively had lower rates of developing PJK or PJF (odds ratio [OR]: 0.4, [0.2-0.8]; P = .011) with the use of prophylaxis. Among those unmatched in T1 pelvic angle, pelvic incidence lumbar lordosis mismatch, and pelvic tilt, prophylaxis reduced the likelihood of developing PJK (OR: 0.5, [0.3-0.9]; P = .023) and PJF (OR: 0.1, [0.03-0.5]; P = .004). Analysis of covariance analysis revealed patients matched in age-adjusted alignment had better cost-utility at 2 years compared with those without prophylaxis ($361 539.25 vs $419 919.43; P < .001). Patients unmatched in age-adjusted criteria also generated better cost ($88 348.61 vs $101 318.07; P = .005) and cost-utility ($450 190.80 vs $564 108.86; P < .001) with use of prophylaxis. CONCLUSION/CONCLUSIONS:Despite additional surgical cost, the optimization of radiographic realignment in conjunction with prophylaxis of the proximal junction appeared to be a more cost-effective strategy, primarily because of the minimization of reoperations secondary to mechanical failure. Even among those not achieving optimal alignment, junctional prophylactic measures were shown to improve cost efficiency.

BACKGROUND:Changing from standing to sitting positions requires rotation of the femur from an almost vertical plane to the horizontal plane. Osteoarthritis of the hip limits hip extension, resulting in less ability to recruit spinopelvic tilt (SPT) while standing and requiring increased SPT while sitting to compensate for the loss of hip range of motion. To date, the effect of total hip arthroplasty (THA) on spinopelvic sitting and standing mechanics has not been reported, particularly in the setting of patients with coexistent sagittal plane spinal deformity. METHODS:A retrospective review was performed of patients ≥18 years of age undergoing unilateral THA for hip osteoarthritis with sitting and standing radiographs made before and after THA. Alignment was analyzed at baseline and follow-up after THA in both standing and sitting positions in a relaxed posture with the fingers resting on top of the clavicles. Patients were grouped according to the presence or absence of sagittal plane deformity preoperatively into 3 groups: no sagittal plane deformity (normal), thoracolumbar (TL) deformity (pelvic incidence-lumbar lordosis [PI-LL] mismatch > 10° and/or T1-pelvic angle [TPA] > 20°), or apparent deformity (PI-LL ≤ 10° and TPA ≤ 20°, but sagittal vertical axis [SVA] > 50 mm). RESULTS:In this study, 192 patients were assessed: 64 had TL deformity, 39 had apparent deformity, and 89 had normal alignment. Overall, patients demonstrated a reduction in standing SVA (45 to 34.1 mm; p < 0.001) and an increase in SPT (14.6° to 15.7°; p = 0.03) after THA. There was a greater change in standing SVA (p < 0.001) among patients with apparent deformity (-29.0 mm) compared with patients with normal alignment (0.9 mm) and patients with TL deformity (-16.3 mm). Those with apparent deformity also experienced the greatest difference (p = 0.03) in postural SPT change (moving from standing to sitting) (-10.1°) from before to after THA when compared with those with normal alignment (-3.6°) and TL deformity (-1.2°). The difference in postural SVA change from before to after THA was also greatest (p < 0.001) in those with apparent deformity (32.1 mm) compared with those with normal alignment (6.5 mm) and TL deformity (17.3 mm). CONCLUSIONS:Postural changes in spinopelvic alignment vary after THA depending on the presence of TL deformity or apparent deformity due to hip flexion contracture. Patients with apparent deformity had larger changes in standing and sitting alignment than patients with TL deformity or patients with normal alignment. The assessment of global sagittal alignment findings can be used to predict the likelihood of improvement in sagittal alignment after THA. LEVEL OF EVIDENCE/METHODS:Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.