Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective analysis of outcomes in cervical spine and shoulder arthroscopy patients. OBJECTIVE:The objective of this study is to assess differential improvements in health-related quality of life for cervical spine surgery compared with shoulder surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:An understanding of outcome differences between different types of orthopedic surgeries is helpful in counseling patients about expected postoperative recovery. This study compares outcomes in patients undergoing cervical spine surgery with arthroscopic shoulder surgery using computer-adaptive Patient-reported Outcome Information System scores. MATERIALS AND METHODS/METHODS:Patients undergoing cervical spine surgery (1-level or 2-level anterior cervical discectomy and fusion, cervical disc replacement) or arthroscopic shoulder surgery (rotator cuff repair±biceps tenodesis) were grouped. Patient-reported Outcome Information System scores of physical function, pain interference, and pain intensity at baseline and at 3, 6, and 12 months were compared using paired t tests. RESULTS:Cervical spine (n=127) and shoulder (n=91) groups were similar in sex (25.8% vs. 41.8% female, P=0.731) but differed in age (51.6±11.6 vs. 58.60±11.2, P<0.05), operative time (148.3±68.6 vs. 75.9±26.9 min, P<0.05), American Society of Anesthesiologists (ASAs) (2.3±0.6 vs. 2.0±0.5, P=0.001), smoking status (15.7% vs. 4.4%, P=0.008), and length of stay (1.1±1.0 vs. 0.3±0.1, P=0.000). Spine patients had worse physical function (36.9 ±12.6 vs. 49.4±8.6, P<0.05) and greater pain interference (67.0±13.6 vs. 61.7±4.8, P=0.001) at baseline. Significant improvements were seen in all domains by 3 months for both groups, except for physical function after shoulder surgery. Spine patients had greater physical function improvements at all timepoints (3.33 vs. -0.43, P=0.003; 4.81 vs. 0.08, P=0.001; 6.5 vs. -5.24, P=<0.05). Conversely, shoulder surgery patients showed better 6-month improvement in pain intensity over spine patients (-8.86 vs. -4.46, P=0.001), but this difference resolved by 12 months. CONCLUSIONS:Cervical spine patients had greater relative early improvement in physical function compared with shoulder patients, whereas pain interference and intensity did not significantly differ between the 2 groups after surgery. This will help in counseling patients about relative difference in recovery and improvement between the 2 surgery types. LEVEL OF EVIDENCE/METHODS:III.

ABSTRACT/UNASSIGNED:Rigoletto, composed by Giuseppe Verdi, is one of the most commonly performed operas around the world. At the time of its 1851 premiere in Venice, the work was remarkable for its portrayal of a main character with a spinal deformity. Through the music of Rigoletto, Verdi explored the societal tensions surrounding physical deformity in the 19th century, providing valuable lessons about the importance of approaching patient care with compassion and empathy in the present day.

Technological advances have paved the way for surgical innovation in spine surgery. These advances have allowed for the creation of more accurate and less invasive surgical techniques. Spine surgeons play a critical role in the integration of new technology into the surgical workflow with the goal of improving safety, efficiency, and clinical outcomes. Navigation and robotic techniques are emerging technologies that have begun to revolutionize spine surgery. One particular advancement these technologies have recently enabled is single position prone lateral surgery. This review provides a history and brief overview of the different applications of new technologies in spine surgery. It will also discuss their enablement of single position prone lateral surgery in order to more critically evaluate their utilization.

OBJECTIVE:The objective of this study was to use an unsupervised cluster approach to identify patterns of operative adult spinal deformity (ASD) and compare the perioperative outcomes of these groups. METHODS:A multicenter data set included patients with complex surgical ASD, including those with severe deformities, significant surgical complexity, or advanced age who underwent a multilevel fusion. An unsupervised cluster analysis allowing for 10% outliers was used to identify different deformity patterns. The perioperative outcomes of these clusters were then compared using ANOVA, Kruskal-Wallis, and chi-square tests, with p values < 0.05 considered significant. RESULTS:Two hundred eighty-six patients were classified into four clusters of deformity patterns: hyper-thoracic kyphosis (hyper-TK), severe coronal, severe sagittal, and moderate sagittal. Hyper-TK patients had the lowest disability (mean Oswestry Disability Index [ODI] 32.9 ± 17.1) and pain scores (median numeric rating scale [NRS] back score 6, leg score 1). The severe coronal cluster had moderate functional impairment (mean physical component score 34.4 ± 12.3) and pain (median NRS back score 7, leg score 4) scores. The severe sagittal cluster had the highest levels of disability (mean ODI 49.3 ± 15.6) and low appearance scores (mean 2.3 ± 0.7). The moderate cluster (mean 68.8 ± 7.8 years) had the highest pain interference subscores on the Patient-Reported Outcomes Measurement Information System (mean 65.2 ± 5.8). Overall 30-day adverse events were equivalent among the four groups. Fusion to the pelvis was most common in the moderate sagittal (89.4%) and severe sagittal (97.5%) clusters. The severe coronal cluster had more osteotomies per case (median 11, IQR 6.5-14) and a higher rate of 30-day implant-related complications (5.5%). The severe sagittal and hyper-TK clusters had more three-column osteotomies (43% and 32.3%, respectively). Hyper-TK patients had shorter hospital stays. CONCLUSIONS:This cohort of patients with complex ASD surgeries contained four natural clusters of deformity, each with distinct perioperative outcomes.

STUDY DESIGN/METHODS:Retrospective review of a cervical deformity database. OBJECTIVE:This study aimed to develop a model that can predict the postoperative DJK angle by using pre and post-operative radiographic measurements. SUMMARY OF BACKGROUND DATA/BACKGROUND:Distal junctional kyphosis (DJK) is a complication following cervical deformity correction that can reduce of patient quality of life and functional status. Although researchers have identified the risk factors for DJK, no model has been proposed to predict the magnitude of DJK. METHODS:The DJK angle was defined as the Cobb angle from LIV to LIV-2 with traditional DJK (tDJK) having a DJK angle change >10°. Models were trained using 66.6% of the randomly selected patients and validated in the remaining 33.3%. Pre-and post-operative radiographic parameters associated with DJK were identified and ranked using a conditional variable importance table. Linear regression models were developed using the factors most strongly associated with the postoperative DJK angle. RESULTS:131 patients were included with a mean follow-up duration of 14±8 months. The mean postoperative DJK angle was 14.6±14° and occurred in 35% of the patients. No significant differences between the training and validation cohort were observed. The variables most associated with post-operative DJK were: preoperative DJK angle (DJKApre), postoperative C2- lower Instrumented vertebral tilt (C2-LIV), and change in cervical lordosis (∆CL). The model identified the following equation as predictive of DJKA: DJKA=9.365 + (0.123*∆CL) - (0.315* ∆C2-LIV) - (0.054*DJKApre). The predicted and actual postoperative DJKA values were highly correlated (R=0.871, R2=0.759, P<0.001). CONCLUSION/CONCLUSIONS:The variables that most increased the DJK angle were the preoperative DJK angle, postoperative alignment within the construct, and change in CL. Future studies can build upon the model developed to be applied in a clinical setting when planning for cervical deformity correction.

BACKGROUND:Patients with less severe adult spinal deformity undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how much clinical improvement is due to sagittal correction rather than treatment of the spondylotic process. PURPOSE/OBJECTIVE:Determine baseline thresholds in radiographic parameters that, when exceeded, may result in substantive clinical improvement from surgical correction. STUDY DESIGN/METHODS:Retrospective. METHODS:ASD patients with BL and 2-year(2Y) data were included. Parameters assessed: SVA, PI-LL, PT, T1PA, L1PA, L4-S1 Lordosis, C2-C7 SVA(cSVA), C2-T3, C2 Slope(C2S). Outcomes: Good Outcome(GO) at 2Y: [Meeting either: 1) SCB for ODI(change greater than 18.8), or 2) ODI<15 and SRS-Total>4.5. Binary logistic regression assessed each parameter to determine if correction was more likely needed to achieve GO. Conditional inference tree(CIT) run machine learning analysis generated baseline thresholds for each parameter, above which, correction was necessary to achieve GO. RESULTS:We included 431 ASD patients. There were 223(50%) that achieved a GO by two years. Binary logistic regression analysis demonstrated, with increasing baseline severity in deformity, sagittal correction was more often seen in those achieving GO for each parameter(all P<0.001). Of patients with baseline T1PA above the threshold, 95% required correction to meet Good Outcome(95% vs. 54%,P<0.001). A baseline PI-LL above 10° (74% of patients meeting GO) needed correction to achieve GO (OR: 2.6,[95% CI 1.4-4.8]). A baseline C2 slope above 15° also necessitated correction to obtain clinical success (OR: 7.7,[95% CI 3.7-15.7]). CONCLUSION/CONCLUSIONS:Our study highlighted point may be present at which sagittal correction has an outsized influence on clinical improvement, reflecting the line where deformity becomes a significant contributor to disability. These new thresholds give us insight into which patients may be more suitable for sagittal correction, as opposed to intervention for the spondylotic process only, leading to a more efficient utility of surgical intervention for adult spinal deformity. LEVEL OF EVIDENCE/METHODS:III.

STUDY DESIGN/METHODS:Retrospective review of a multicenter comprehensive cervical deformity (CD) database. OBJECTIVE:To develop a novel risk index specific to each patient to aid in patient counseling and surgical planning to minimize postop DJK occurrence. BACKGROUND:Distal junctional kyphosis(DJK) is a radiographic finding identified after patients undergo instrumented spinal fusions which can result in sagittal spinal deformity, pain and disability, and potentially neurological compromise. DJK is considered multifactorial in nature and there is a lack of consensus on the true etiology of DJK. METHODS:CD pts with baseline(BL) and at least 1-year postoperative(1Y) radiographic follow-up were included. A patient-specific DJK score was created through use of unstandardized Beta weights of a multivariate regression model predicting DJK(end of fusion construct to the 2nd distal vertebra change in this angle by<-10° from BL to postop). RESULTS:110 CD pts included(61yrs, 66.4%F, 28.8kg/m2). 31.8% of these pts developed DJK (16.1% 3M, 11.4% 6M, 62.9% 1Y). At BL, DJK pts were more frail and underwent combined approach more (both P<0.05). Multivariate model regression analysis identified individualized scores through creation of a DJK equation: -0.55+0.009(BL Inclination) -0.078(Pre Inflection)+5.9×10-5(BL LIV angle) + 0.43(combine approach) - 0.002(BL TS-CL)- 0.002(BL PT)- 0.031(BL C2-C7)+ 0.02(∆T4-T12)+ 0.63(Osteoporosis)- 0.03(anterior approach) - 0.036( Frail) - 0.032(3 column osteotomy). This equation has a 77.8% accuracy of predicting DJK. A score ≥81 predicted DJK with an accuracy of 89.3%. The BL reference equation correlated with 2Y outcomes of NSR-Back percentage(P=0.003), reoperation(P=0.04), and MCID for EQ. 5D(P=0.04). CONCLUSIONS:This study proposes a novel risk index of DJK development that focuses on potentially modifiable surgical factors as well as established patient-related and radiographic determinants. The reference model created demonstrated strong correlations with relevant two year outcome measures, including axial pain-related symptoms, occurrence of related reoperations, and the achievement of minimal clinically importance differences for EQ. 5D.

Study Design: Retrospective review of prospective database. Objectives: Vertebral pelvic angles (VPAs) account for complexity in spine shape by assessing the relative position of each vertebra with regard to the pelvis. This study uses VPAs to investigate the shape of the fused spine after T10-pelvis fusion, in patients with adult spinal deformity (ASD), and then explores its association with proximal junctional kyphosis (PJK). Methods: Included patients had radiographic evidence of ASD and underwent T10-pelvis realignment. VPAs were used to construct a virtual shape of the post-operative spine. VPA-predicted and actual shapes were then compared between patients with and without PJK. Logistic regression was used to identify components of the VPA-based model that were independent predictors of PJK occurrence and post-operative shape. Results: 287 patients were included. VPA-predicted shape was representative of the true post-operative contour, with a mean point-to-point error of 1.6-2.9% of the T10-S1 spine length. At 6-weeks follow-up, 102 patients (35.5%) developed PJK. Comparison of the true post-operative shapes demonstrated that PJK patients had more posteriorly translated vertebrae from L3 to T7 (P <.001). Logistic regression demonstrated that L3PA (P =.047) and T11PA (P <.001) were the best independent predictors of PJK and were, in conjunction with pelvic incidence, sufficient to reproduce the actual spinal contour (error <3%). Conclusions: VPAs are reliable in reproducing the true, post-operative spine shape in patients undergoing T10-pelvis fusion for ASD. Because VPAs are independent of patient position, L3PA, T11PA, and PI measurements can be used for both pre- and intra-operative planning to ensure optimal alignment.

Study Design: Multicenter, prospective cohort Objectives: Malalignment following adult spine deformity (ASD) surgery can impact outcomes and increase mechanical complications. We assess whether preoperative goals for sagittal alignment following ASD surgery are achieved. Methods: ASD patients were prospectively enrolled based on 3 criteria: deformity severity (PI-LL ≥25°, TPA ≥30°, SVA ≥15 cm, TCobb≥70° or TLCobb≥50°), procedure complexity (≥12 levels fused, 3-CO or ACR) and/or age (>65 and ≥7 levels fused). The surgeon documented sagittal alignment goals prior to surgery. Goals were compared with achieved alignment on first follow-up standing radiographs. Results: The 266 enrolled patients had a mean age of 61.0 years (SD = 14.6) and 68% were women. Mean instrumented levels was 13.6 (SD = 3.8), and 23.2% had a 3-CO. Mean (SD) offsets (achieved-goal) were: SVA = −8.5 mm (45.6 mm), PI-LL = −4.6° (14.6°), TK = 7.2° (14.7°), reflecting tendencies to undercorrect SVA and PI-LL and increase TK. Goals were achieved for SVA, PI-LL, and TK in 74.4%, 71.4%, and 68.8% of patients, respectively, and was achieved for all 3 parameters in 37.2% of patients. Three factors were independently associated with achievement of all 3 alignment goals: use of PACs/equivalent for surgical planning (P <.001), lower baseline GCA (P =.009), and surgery not including a 3-CO (P =.037). Conclusions: Surgeons failed to achieve goal alignment of each sagittal parameter in ∼25-30% of ASD patients. Goal alignment for all 3 parameters was only achieved in 37.2% of patients. Those at greatest risk were patients with more severe deformity. Advancements are needed to enable more consistent translation of preoperative alignment goals to the operating room.

Study Design: Multicenter comparative cohort. Objective: Studies have shown markedly higher rates of complications and all-cause mortality following surgery for adult cervical deformity (ACD) compared with adult thoracolumbar deformity (ATLD), though the reasons for these differences remain unclear. Our objectives were to compare baseline frailty, disability, and comorbidities between ACD and complex ATLD patients undergoing surgery. Methods: Two multicenter prospective adult spinal deformity registries were queried, one ATLD and one ACD. Baseline clinical and frailty measures were compared between the cohorts. Results: 616 patients were identified (107 ACD and 509 ATLD). These groups had similar mean age (64.6 vs 60.8 years, respectively, P =.07). ACD patients were less likely to be women (51.9% vs 69.5%, P <.001) and had greater Charlson Comorbidity Index (1.5 vs.9, P <.001) and ASA grade (2.7 vs 2.4, P <.001). ACD patients had worse VR-12 Physical Component Score (PCS, 25.7 vs 29.9, P <.001) and PROMIS Physical Function Score (33.3 vs 35.3, P =.031). All frailty measures were significantly worse for ACD patients, including hand dynamometer (44.6 vs 55.6 lbs, P <.001), CSHA Clinical Frailty Score (CFS, 4.0 vs 3.2, P <.001), and Edmonton Frailty Scale (EFS, 5.15 vs 3.21, P <.001). Greater proportions of ACD patients were frail (22.9% vs 5.7%) or vulnerable (15.6% vs 10.9%) based on EFS (P <.001). Conclusions: Compared with ATLD patients, ACD patients had worse baseline characteristics on all measures assessed (comorbidities/disability/frailty). These differences may help account for greater risk of complications and all-cause mortality previously observed in ACD patients and facilitate strategies for better preoperative optimization.