Faculty Bibliography

OBJECTIVE:The objective of this study was to identify the effect of baseline cervical deformity (CD) on proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in patients with adult spinal deformity (ASD). METHODS:This study was a retrospective analysis of a prospectively collected, multicenter database comprising ASD patients enrolled at 13 participating centers from 2009 to 2018. Included were ASD patients aged > 18 years with concurrent CD (C2-7 kyphosis < -15°, T1S minus cervical lordosis > 35°, C2-7 sagittal vertical axis > 4 cm, chin-brow vertical angle > 25°, McGregor's slope > 20°, or C2-T1 kyphosis > 15° across any three vertebrae) who underwent surgery. Patients were grouped according to four deformity classification schemes: Ames and Passias CD modifiers, sagittal morphotypes as described by Kim et al., and the head versus trunk balance system proposed by Mizutani et al. Mean comparison tests and multivariable binary logistic regression analyses were performed to assess the impact of these deformity classifications on PJK and PJF rates up to 3 years following surgery. RESULTS:A total of 712 patients with concurrent ASD and CD met the inclusion criteria (mean age 61.7 years, 71% female, mean BMI 28.2 kg/m2, and mean Charlson Comorbidity Index 1.90) and underwent surgery (mean number of levels fused 10.1, mean estimated blood loss 1542 mL, and mean operative time 365 minutes; 70% underwent osteotomy). By approach, 59% of the patients underwent a posterior-only approach and 41% underwent a combined approach. Overall, 277 patients (39.1%) had PJK by 1 year postoperatively, and an additional 189 patients (26.7%) developed PJK by 3 years postoperatively. Overall, 65 patients (9.2%) had PJF by 3 years postoperatively. Patients classified as having a cervicothoracic deformity morphotype had higher rates of early PJK than flat neck deformity and cervicothoracic deformity patients (p = 0.020). Compared with the head-balanced patients, trunk-balanced patients had higher rates of PJK and PJF (both p < 0.05). Examining Ames modifier severity showed that patients with moderate and severe deformity by the horizontal gaze modifier had higher rates of PJK (p < 0.001). CONCLUSIONS:In patients with concurrent cervical and thoracolumbar deformities undergoing isolated thoracolumbar correction, the use of CD classifications allows for preoperative assessment of the potential for PJK and PJF that may aid in determining the correction of extending fusion levels.

Long-segment adult spinal deformity (ASD) constructs carry a high risk of mechanical complications. Pelvic fixation was introduced to improve distal construct mechanics and has since become the standard for long constructs spanning the lumbosacral junction. Pelvic fixation strategies have evolved substantially over the years. Numerous techniques now use a variety of entry points, screw trajectories, and construct configurations. We review the various strategies for pelvic fixation in ASD in a systematic review of the literature and update the techniques employed in the International Spine Study Group Complex Adult Deformity Surgery database.

OBJECTIVE:We sought to assess factors contributing to optimal radiographic outcomes. METHODS:Operative adult spinal deformity (ASD) patients with baseline and 5-year (5Y) data were included. Optimal alignment (O) was defined as improving in at least 1 Scoliosis Research Society-Schwab modifier without worsening in any Scoliosis Research Society-Schwab modifier. A robust outcome was defined as having optimal alignment 2 years (2Y) post operation that was maintained at 5Y. Predictors of robust outcomes were identified using multivariate regression analysis, with a conditional inference tree for continuous variables. RESULTS:Two-hundred and ninety-seven ASD patients met inclusion criteria. Most patients (77.4%) met O at 6W, which decreased to 54.2% at 2Y. The majority of patients (89.4%) that met O at 2Y went on to meet radiographic durability at 5Y (48.5% of total cohort). Rates of junctional failure were higher in O2+5- compared with O2+5- (P = 0.013), with reoperation rates of 17.2% due to loss of alignment. Multivariable regression identified the following independent predictors of optimal alignment at 5Y in those that had O at 2Y: inadequate correction of pelvic tilt and overcorrection of the difference between pelvic incidence and lumbar lordosis (P < 0.05). Increased age, body mass index, and invasiveness were the most significant nonradiographic predictors for not achieving 5Y durability (P < 0.05). CONCLUSIONS:The durability of optimal alignment after ASD corrective surgery was seen in about half of the patients at 5Y. While the majority of patients at 2Y maintained their radiographic outcomes at 5Y, major contributors to loss of alignment included junctional failure and adjacent region compensation, with only a minority of patients losing correction through the existing construct. The reoperation rate for loss of alignment was 17.2%. Loss of alignment requiring reoperation had a detrimental effect on 5Y clinical outcomes.

OBJECTIVE:Identify trends of navigation and robotic-assisted elective spine surgeries. METHODS:Elective spine surgery patients between 2007 and 2015 in the Nationwide Inpatient Sample (NIS) were isolated by ICD-9 codes for Navigation [Nav] or Robotic [Rob]-Assisted surgery. Basic demographics and surgical variables were identified via chi-squared and t tests. Each system was analyzed from 2007 to 2015 for trends in usage. RESULTS:Included 3,759,751 patients: 100,488 Nav; 4724 Rob. Nav were younger (56.7 vs 62.7 years), had lower comorbidity index (1.8 vs 6.2, all p < 0.05), more decompressions (79.5 vs 42.6%) and more fusions (60.3 vs 52.6%) than Rob. From 2007 to 2015, incidence of complication increased for Nav (from 5.8 to 21.7%) and Rob (from 3.3 to 18.4%) as well as 2-3 level fusions (from 50.4 to 52.5%) and (from 1.3 to 3.2%); respectively. Invasiveness increased for both (Rob: from 1.7 to 2.2; Nav: from 3.7 to 4.6). Posterior approaches (from 27.4 to 41.3%), osteotomies (from 4 to 7%), and fusions (from 40.9 to 54.2%) increased in Rob. Anterior approach for Rob decreased from 14.9 to 14.4%. Nav increased posterior (from 51.5% to 63.9%) and anterior approaches (from 16.4 to 19.2%) with an increase in osteotomies (from 2.1 to 2.7%) and decreased decompressions (from 73.6 to 63.2%). CONCLUSIONS:From 2007 to 2015, robotic and navigation systems have been performed on increasingly invasive spine procedures. Robotic systems have shifted from anterior to posterior approaches, whereas navigation computer-assisted procedures have decreased in rates of usage for decompression procedures.

BACKGROUND/UNASSIGNED:Cannabis is the most commonly used recreational drug in the USA. Studies evaluating cannabis use and its impact on outcomes following cervical spinal fusion (CF) are limited. This study sought to assess the impact of isolated (exclusive) cannabis use on postoperative outcomes following CF by analyzing outcomes like complications, readmissions, and revisions. METHODS/UNASSIGNED:The New York Statewide Planning and Research Cooperative System (SPARCS) was queried for patients who underwent CF between January 2009 and September 2013. Inclusion criteria were age ≥18 years and either a minimum 90-day (for complications and readmissions) or 2-year (for revisions) follow-up surveillance. Patients with systemic disease, osteomyelitis, cancer, trauma, and concomitant substance or polysubstance abuse/dependence were excluded. Patients with a preoperative International Classification of Diseases, 9th Edition, Clinical Modification (ICD-9-CM) diagnosis of isolated cannabis abuse (Cannabis) or dependence were identified. The primary outcome measures were 90-day complications, 90-day readmissions, and two-year revisions following CF. Cannabis patients were 1:1 propensity score-matched by age, gender, race, Deyo score, surgical approach, and tobacco use to non-cannabis users and compared for outcomes. Multivariate binary stepwise logistic regression models identified independent predictors of outcomes. RESULTS/UNASSIGNED:432 patients (n=216 each) with comparable age, sex, Deyo scores, tobacco use, and distribution of anterior or posterior surgical approaches were identified (all p>0.05). Cannabis patients were predominantly Black (27.8% vs. 12.0%), primarily utilized Medicaid (29.6% vs. 12.5%), and had longer LOS (3.0 vs. 1.9 days), all p≤0.001. Both cohorts experienced comparable rates of 90-day medical and surgical, as well as overall complications (5.6% vs. 3.7%) and two-year revisions (4.2% vs. 2.8%, p=0.430), but isolated cannabis patients had higher 90-day readmission rates (11.6% vs. 6.0%, p=0.042). Isolated cannabis use independently predicted 90-day readmission (Odds Ratio=2.0), but did not predict any 90-day complications or two year revisions (all p>0.05). CONCLUSION/UNASSIGNED:.

STUDY DESIGN/METHODS:Retrospective review of prospective multicenter data. OBJECTIVES/OBJECTIVE:This study aimed to investigate the shape of TK before and after fusion in ASD patients treated with long fusion. METHODS:test. RESULTS:= .032). CONCLUSIONS:Posterior spinal fusion for ASD alters the magnitude and shape of thoracic kyphosis. While 60% of patients had a normal TK at baseline, 30% of those patients developed iatrogenic hyperkyphosis postoperatively. Patients with baseline hypokyphosis were more likely to be corrected to normal TK than hyperkyphotic patients. Future research should investigate TK restoration in ASD and its impact on clinical outcomes and complications.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:Understand the benefit of addressing malalignment in revision surgery for PJK. SUMMARY OF BACKGROUND DATA/BACKGROUND:Proximal junctional kyphosis(PJK) is a common cause of revision surgery for ASD patients. During a revision, surgeons may elect to perform a proximal extension of the fusion, or also correct the source of the lumbo-pelvic mismatch. METHODS:Recurrent PJK following revision surgery was the primary outcome. Revision surgical strategy was the primary predictor(proximal extension of fusion alone compared to combined sagittal correction and proximal extension). Multivariable logistic regression determined rates of recurrent PJK between the two surgical groups with lumbo-pelvic surgical correction assessed through improving ideal alignment in one or more alignment criteria(Global Alignment and Proportionality[GAP],Roussouly-type, and Sagittal Age-Adjusted Score[SAAS]). RESULTS:151 patients underwent revision surgery for PJK. PJK occurred at a rate of 43.0%, and PJF at 12.6%. Patients proportioned in GAP post-revision had lower rates of recurrent PJK(23% vs. 42%;OR: 0.3,95% CI:[0.1-0.8];P=0.024). Following adjusted analysis, patients who were ideally aligned in 1 of 3 criteria (Matching in SAAS and/or Roussouly matched and/or achieved GAP proportionality) had lower rates of recurrent PJK (36% vs. 53%;OR: 0.4,95% CI:[0.1-0.9];P=0.035) and recurrent PJF(OR: 0.1,95% CI:[0.02-0.7];P=0.015). Patients ideally aligned in 2 of 3 criteria avoid any development of PJF(0% vs. 16%, P<0.001). CONCLUSION/CONCLUSIONS:Following revision surgery for proximal junctional kyphosis, patients with persistent poor sagittal alignment showed increased rates of recurrent proximal junctional kyphosis compared with patients who had abnormal lumbo-pelvic alignment corrected during the revision. These findings suggest addressing the root cause of surgical failure in addition to proximal extension of the fusion may be beneficial.

STUDY DESIGN/METHODS: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:< .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.

STUDY DESIGN/METHODS:Retrospective review of a prospectively enrolled adult spinal deformity (ASD) database. OBJECTIVE:To investigate what patient factors elevate the risk of sub-optimal outcomes after deformity correction. BACKGROUND:Currently, it is unknown what factors predict a poor outcome after adult spinal deformity surgery, which may require increased pre-operative consideration and counseling. METHODS:Patients >18yrs undergoing surgery for ASD(scoliosis≥20°, SVA≥5 cm, PT≥25°, or TK≥60°). An unsatisfactory outcome was defined by the following categories met at 2Y: (1) clinical: deteriorating in ODI at 2Y f/u (2) complications/reop: having a reoperation and major complication were deemed high risk for poor outcomes postoperatively (HR). Multivariate analyses assessed predictive factors of HR patients in adult spinal deformity patients. RESULTS:633 ASD (59.9 years, 79%F, 27.7 kg/m2, CCI: 1.74) were included. Baseline severe Schwab modifier incidence (++): 39.2% PI-LL, 28.8% SVA, 28.9% PT. 15.5% of patients deteriorated in ODI by 2 years, while 7.6% underwent a reoperation and had a major complication. This categorized 11 (1.7%) as HR. HR were more comorbid in terms of arthritis (73%) heart disease (36%) and kidney disease (18%), P<0.001. Surgically, HR had greater EBL (4431ccs), underwent more osteotomies (91%), specifically Ponte(36%) and Three Column Osteotomies(55%), which occurred more at L2(91%). HR underwent more PLIFs (45%) and had more blood transfusion units (2641ccs), all P<0.050. The multivariate regression determined a combination of a baseline DRAM score in the 75th percentile, having arthritis and kidney disease, a baseline right lower extremity motor score ≤3, cSVA >65 mm, C2 slope >30.2°, CTPA >5.5° for an R2 value of 0.535 (P<0.001). CONCLUSIONS:When addressing adult spine deformities, poor outcomes tends to occur in severely comorbid patients with major baseline psychological distress scores, poor neurologic function, and concomitant cervical malalignment.

OBJECTIVE:The aim of this study was to investigate whether surgery for high-risk patients is being optimized over time and if poor outcomes are being minimized. METHODS:Patients who underwent surgery for cervical deformity (CD) and were ≥ 18 years with baseline and 2-year data were stratified by year of surgery from 2013 to 2018. The cohort was divided into two groups based on when the surgery was performed. Patients in the early cohort underwent surgery between 2013 and 2015 and those in the recent cohort underwent surgery between 2016 and 2018. High-risk patients met at least 2 of the following criteria: 1) baseline C2-7 Cobb angle > 15°, mismatch between T1 slope and cervical lordosis ≥ 35°, C2-7 sagittal vertical axis > 4 cm, or chin-brow vertical angle > 25°; 2) age ≥ 70 years; 3) severe baseline frailty (Miller index); 4) Charlson Comorbidity Index (CCI) ≥ 1 SD above the mean; 5) three-column osteotomy as treatment; and 6) fusion > 10 levels or > 7 levels for elderly patients. The mean comparison analysis assessed differences between groups. Stepwise multivariable linear regression described associations between increasing year of surgery and complications. RESULTS:Eighty-two CD patients met high-risk criteria (mean age 62.11 ± 10.87 years, 63.7% female, mean BMI 29.70 ± 8.16 kg/m2, and mean CCI 1.07 ± 1.45). The proportion of high-risk patients increased with time, with 41.8% of patients in the early cohort classified as high risk compared with 47.6% of patients in the recent cohort (p > 0.05). Recent high-risk patients were more likely to be female (p = 0.008), have a lower BMI (p = 0.038), and have a higher baseline CCI (p = 0.013). Surgically, high-risk patients in the recent cohort were more likely to undergo low-grade osteotomy (p = 0.003). By postoperative complications, recent high-risk patients were less likely to experience any postoperative adverse events overall (p = 0.020) or complications such as dysphagia (p = 0.045) at 2 years. Regression analysis revealed increasing year of surgery to be correlated with decreasing minor complication rates (p = 0.030), as well as lowered rates of distal junctional kyphosis by 2 years (p = 0.048). CONCLUSIONS:Over time, high-risk CD patients have an increase in frequency and comorbidity rates but have demonstrated improved postoperative outcomes. These findings suggest that spine surgeons have improved over time in optimizing selection and reducing potential adverse events in high-risk patients.