Faculty Bibliography

BACKGROUND CONTEXT: Sagittal alignment is integral to a patient's quality of life. Posterior spinal fusion (PSF) is currently the standard for correcting adolescent idiopathic scoliosis (AIS). Vertebral body tethering (VBT) is a fusionless growth modulating surgical technique used to treat AIS. It relies on the Hueter-Volkmann Law. Indications for this procedure include patients who have coronal curves up to 50degree, growth remaining, and no excessive thoracic kyphosis. VBT has been shown to have good coronal plane deformity correction. There have been fewer examinations of the sagittal effects of VBT. PURPOSE: To determine if VBT is a non-inferior treatment for correction of AIS with regard to sagittal alignment compared to PSF. STUDY DESIGN/SETTING: Multicenter retrospective cohort study. PATIENT SAMPLE: Patients with AIS who underwent correction surgeries with LIV in the lumbar spine from 2013 to 2021 with pre- and minimum two-year postoperative standing full spine plain films. OUTCOME MEASURES: Sagittal vertical axis (SVA), cervical SVA (cSVA), pelvic tilt (PT), thoracic kyphosis (TK), cervical lordosis (CL), L4-S1 lordosis (L4L), T1 pelvic angle (TPA) and pelvic incidence lumbar lordosis mismatch (PI-LL).
METHOD(S): Radiographic analyses was completed with independent samples t-test with significance set to p <0.05.
RESULT(S): A total of 99 patients were included, 49 VBT and 50 PSF. There were no differences in age or levels instrumented between groups. The VBT cohort Lenke class breakdown is 23% 1A, 13% 1C, 31% 3C. 18% 5C, and 15% 6C, while the PSF cohort consisted of 42% 1A, 6% 1B, 2% 2C, 2% 3B, 12% 3C, 2% 5B, 24% 5C, and 10% 6C. At Baseline, the VBT cohort had lower SVA (-0.7mm+/-3.7 vs 2.2mm+/-5.0, p=0.001), CL (-0.9degree+/-18.2 vs 11.6degree+/-12.8, p=0.001), L4-S1 Lordosis (20.7degree+/-16.0 vs 41.6degree+/-10.2, p=0.001), and higher cSVA (3.3mm+/-1.6 vs -0.95mm+/-3.1, p=0.001) than those who were fused. Postoperatively, VBT patients have an overall higher L4-S1 Lordosis (36.0degree+/-10.1vs 18.3degree+/-12.5, p=0.001), cSVA (3.4mm+/-1.4 vs -3.7mm+/-2.1, p=0.001), and lower CL (-4.3degree+/-18.4 vs 7.0degree+/-12.2, p=0.001). The PSF cohort had a larger change in cSVA (2.8mm+/-4.0 vs 0mm+/-1.6, p=0.001) from baseline to 2-year follow-up compared to VBT. No differences in the change of L4-S1 Lordosis (VBT 1.5degree+/-12.3 vs 4.1degree+/-10.9, p=0.3), TPA (VBT -1.6degree+/-6.8 vs -1.4degree+/-8.5, p=0.89), PT (VBT -0.5degree+/-7.8 vs -1.9degree+/-8.5, p=0.42), or PI-LL (0.2degree+/-12.0 vs -0.5degree+/-14.0, p=0.81) were observed.
CONCLUSION(S): VBT and PSF for AIS result in statistically similar changes in sagittal alignment parameters. The fact that we showed similar results comparing sagittal alignment in fusion and VBT groups indicates that VBT is non-inferior from a sagittal perspective. It is important to maintain sagittal alignment when correcting AIS. Future work can examine the long-term effect of VBT on sagittal alignment. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: Reducing fluoroscopy time and radiation exposure in the operating room is beneficial for the patient and surgical team. Placement of an interbody device during lateral transpsoas approach is traditionally carried out using anterior-posterior and lateral fluoroscopy. In this setting, 3-dimensional computed tomography (CT)-based spinal navigation of cage and pedicle screw/rod placement for LLIF procedure may result in decreased radiation exposure compared with fluoroscopically-guided LLIF. We sought to present our experience with the use of CT-based spinal navigation for the LLIF procedure and evaluate rates of intraoperative complications and radiation exposure. PURPOSE: To determine if computer-navigation guided LLIF will have equivalent outcomes with decreased radiation dose compared to fluoroscopy-guided LLIF. STUDY DESIGN/SETTING: Single-center retrospective review. PATIENT SAMPLE: This study included 250 patients over 18 years of age who underwent LLIF with <4 levels fused (age: 61.4 +/- 10.8 yrs, BMI: 29.7 +/- 6.1 7 kg/m2). OUTCOME MEASURES: Intraoperative and 90-day complications, radiation exposure and cage placement.
METHOD(S): Patients were separated into two groups: fluoroscopy-guided LLIF (n=224), and navigated LLIF (n=26). Cage placement was assessed on postoperative radiographs by dividing the disc space into quarters, anterior to posterior.
RESULT(S): In terms of operative characteristics, fluoroscopy dosage was significantly greater in the fluoroscopically-guided LLIF cohort (55.1 +/- 57.4 mGy vs 34.0 +/- 24.9 mGy, p=0.002). There were no significant differences between fluoroscopically-guided LLIFs and navigated LLIFs in overall intraoperative complication rate (4% Fluoro vs 0% Nav, p=0.3), rate of durotomy (2.2 % Fluoro vs 0% Nav, p=0.44), or estimated blood loss (322 +/- 330.3 cc Flouro vs 299.5 +/- 198.6 cc Nav, p=0.6). The rate of postoperative complications (26.8% Fluoro vs 26.9% Nav), neurologic complications (5.4% Fluoro vs 3.8% Nav), surgical site infections (1.3% Fluoro vs 3.8% Nav), mechanical complications (1.8% Fluoro vs 0% Nav) was not significantly different. There was no significant difference in the rate of unplanned return to the operating room within 90 days (1.8% Fluoro vs 0% Nav). Cage placement was similar between the two groups (p=0.29).
CONCLUSION(S): We report an average radiation exposure with navigated LLIFs of 34.0 mGy, significantly lower than the 55.1 mGy in the fluoroscopically-guided LLIF group. The length of stay and perioperative complication rate was equivalent between the groups. These data support the use of CT-based navigation for placement of the cage and pedicle screws/rod construct for LLIF procedure. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: Patients with coronal malalignment with trunk shift toward the convexity of the main coronal curve, and oblique takeoff at the lumbosacral junction, present a unique problem for deformity correction. PURPOSE: To evaluate fractional curve and coronal malalignment correction, and rate of complications and unplanned revision in Bao Type C patients, compared to Bao Type A and B patients. STUDY DESIGN/SETTING: Retrospective review of prospectively collected singlecenter database. PATIENT SAMPLE: This study included 1039 ASD patients (age: 46 +/- 23 y; mFI:.4 +/-.7; levels fused: 10.0 +/- 4.2). OUTCOME MEASURES: Outcomes evaluated were coronal alignment and fractional curve correction, and rates of revision surgery at two-year follow-up.
METHOD(S): A total of 1039 adult spinal deformity patients (age: 46 +/- 23 y; mFI:.4 +/-.7; levels fused: 10.0 +/- 4.2), with minimum five levels fused for thoracolumbar scoliosis were divided into three groups, as proposed by Bao et al: type A: CSVL 3cm and C7 plumb shifted to scoliosis' concavity (n=126); type C: CSVL > 3cm and C7 plumb shifted to scoliosis' convexity (n=30). Outcomes evaluated were coronal alignment and fractional curve correction, and rates of revision surgery at two-year follow-up.
RESULT(S): Type C patients more often had fractional curves, and the preoperative magnitude was significantly greater (15.7degree Type C, 12.9degree Type B, 9.6degree Type A, p <0.0001). Of the Type C patients, 50% had pedicle subtraction osteotomy performed, compared with 13.4% Type B, and 13.4% Type A (p <0.0001). Postoperatively, Type C patients continued to have persistently greater fractional curves (7.4degree Type C, 6.7degree Type B, 5.6degree Type A, p=0.026), and worse coronal malalignment (37.8 mm Type C, 34.1 mm Type B, 17.0 mm type A, p<0.0001), though equivalent results with regards to improvement in sagittal alignment, lumbar lordosis, pelvic tilt, and Cobb angle of the major curve. There rate of neurologic complications was higher in the Type C patients, specifically related to TLIF or PSO procedure performed. ALIF procedure in the Type C patients did not confer significant improvement in fractional curve correction, coronal or sagittal alignment correction, or greater lumbar lordosis, compared with TLIF procedure in these patients. There was no difference in the rate of 90-day unplanned readmission or reoperation between the groups. There was no difference in rates of rod fracture or pseudarthrosis at the interbody or PSO site in Type C patients, compared with Type A and B patients. There was no difference in rates or rod fracture, pseudarthrosis, adjacent segment disease, proximal junctional kyphosis, or reoperation for recurrent or persistent malalignment between the two groups at two-year follow-up.
CONCLUSION(S): At two-year follow-up, Type C coronal malalignment patients continue to have worse coronal deformity and fractional curve magnitude compared with Type A and B patients, with no difference, however, in long-term rod fracture, pseudarthrosis or revision surgery rates. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: The ACS-NSQIP and SpineSage are both easy to use and readily available online perioperative risk calculators The ACS-NSQIP calculator predicts perioperative complications after surgery, but lacks more spine-specific predictors. The SpineSage platform was developed as a tool built for predicting complications in spine surgery. While a limited number of studies have shown it be predictive of both overall and major medical complications in spine surgery, large external validation studies are limited and none have directly compared NSQIP against SpineSage in the same cohort of spine surgery patients. PURPOSE: Assess the ACS-NSQIP Risk Calculator and SpineSage informatics platform for prediction of perioperative complications in spine surgery STUDY DESIGN/SETTING: Retrospective. PATIENT SAMPLE: A total of 440 patients undergoing thoracolumbar spine with or without fusion. OUTCOME MEASURES: Any complication, serious complication, pneumonia, cardiac, dural tear, SSI, UTI, VTE, reoperation, death and LOS METHODS: Each patient was entered into the ACS-NSQIP and SpineSage calculators and predicted risk for specific complications were directly compared to actual risks. Paired t-tests compared the differences between calculators and their predictability of complications. Patients were ranked based on risk predicted for each complication and the highest tertile for each was isolated. Multivariate regression controlling for age and gender was used to determine if the highest tertile for each risk calculator had predictability in complications following spine surgery.
RESULT(S): Mean LOS 4.2+3 days, EBL 444+300 mL, operative time 256+240 min, and levels instrumented 2.1+2.3. When assessing the four complications predicted by SpineSage there were significant differences in three of the four variables, as SpineSage underpredicted the risk of all and serious-complications (p.5). Both calculator tertiles were trending towards significance for major medical complications (SpineSage: OR: 2.0, [0.94-4.23], p=.073; ACS-NSQIP: OR: 1.8,[0.96-3.48],p=.067). When examining any medical risk, only ACS NSQIP had significant predictability for any medical complication (OR: 2.1, [1.3-3.3]; p=.003).
CONCLUSION(S): Similar to previous studies, the ACS-NSQIP score underpredicted most complications, with the exception of LOS and death. In contrast to previous studies, our data suggest SpineSage was not predictive of actual rates of complications. As both calculators are highly accessible and provide at least some objective perioperative risk data points, we recommend them as a guiding tool but not as an absolute endpoint for clinical decision making as they may be inaccurate and insensitive. Further, higher powered studies elucidating the findings in this study should be conducted. Additionally, the assessment of these calculators for a specific subset of patients, such as deformity, degenerative or pediatrics, can further help guide clinicians regarding the utility of these calculators for their particular patient populations. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: Diabetic patients with elevated hemoglobin A1C (HbA1C) are at higher risk of developing complications after surgery than their nondiabetic peers. This is especially true of wound complications, including wound infections. Previous research has shown this relationship to be multifactorial, so more investigation is needed into these complications. PURPOSE: Establish pertinent factors which contribute to increased wound complication incidence among diabetic patients undergoing thoracolumbar fusion. STUDY DESIGN/SETTING: Single center retrospective cohort study. PATIENT SAMPLE: This study included 228 patients with a diagnosis of diabetes mellitus who underwent thoracic, lumbar, or thoracolumbar posterior spinal fusion (PSF) from 2013-2018 with preoperative HbA1C values. Patients without preoperative HbA1C results or undergoing cervical fusions were excluded. OUTCOME MEASURES: Development of wound complications and infection in the perioperative period were recorded for analysis. Wound complications were defined as dehiscence, superficial SSI and deep SSI.
METHOD(S): Significant perioperative complications were determined using t-test and chi-square analyses. Complications were tested against confounding factors using binary logistic regressions. Efficacy of various preoperative demographic measures as markers for complication was determined using Receiver Operating Characteristic (ROC) analyses. Cutoff points were calculated by Youden's index. Significance set at p <0.05.
RESULT(S): A total of 228 patients met inclusion. Significant differences in BMI were noted between patients who developed infection (n=7) and those who did not (37.5 kg/m² vs 32.0 kg/m²; p=0.039). In addition, binary logistic regression showed that, controlled for HbA1C, BMI was a significant predictor of infection (OR: 1.110; p=0.043). ROC curve demonstrated an AUC of 0.754 (p=0.022) and Youden's J calculated the cutoff point to be 34.08 kg/m² (Spec: 64.3%, Sens: 85.7%). No differences between those with postop wound complications were noted in HbA1C (7.29 vs 6.88; p=0.345), age (70.14 vs 64.92; p=0.197), gender (vs 71.4% female vs 55.5% female; p=0.469), smoking status (28.6% smoking history vs 33.9% smoking history), levels fused (2.71 vs 2.62; p=0.931), LOS (3.29 vs 4.82; p=0.243). Sub-analysis of superficial infections revealed no significant differences in HbA1C (7.15 vs 6.88; p=0.565), age (70.8 vs 64.9; p=0.175), BMI (36.5 vs 32.1; p=0.114), levels fused (2.5 vs 2.6; p=0.911), gender (66.7% female vs 55.4% female; p=0.697), smoking status (33.3% smoking history vs 33.7% smoking history; p=1.000), or LOS (2.8 vs 4.8; p=0.159). Subanalysis of deep SSI revealed only one infection.
CONCLUSION(S): BMI above 34.08 kg/m² is a significant predictor of postoperative infection in diabetic patients undergoing posterior fusion. To ensure optimal outcomes, diabetic patients should be encouraged to get below this threshold before surgery. More research must be done to further establish the relationship of BMI with regard to superficial and deep infections. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: The fractional curve is the curve below the major curve of a lumbar or thoracolumbar scoliosis, and while it is often the primary driver of the adult spinal deformity patient's decision to proceed with surgery, a treatment strategy to identify and address the fractional curve is not widely examined. There is a paucity of data evaluating the ideal strategy to correct the lumbosacral fractional curve in ASD surgery. PURPOSE: We sought to evaluate the impact of interbody fusion at L4-L5 and/or L5-S1 compared with posterior fusion alone on fractional curve correction, and rate of instrumentation related complications at the lumbosacral junction. STUDY DESIGN/SETTING: Retrospective review of prospectively collected single center database. PATIENT SAMPLE: A total of 592 ASD patients (Age: 48 +/- 23 y; mFI:.4 +/-.7; Levels fused: 10.3 +/- 4.1). OUTCOME MEASURES: Outcomes evaluated were fractional curve correction, overall deformity correction and rates of revision surgery for pseudarthrosis or rod fracture at the lumbosacral junction.
METHOD(S): A total of 592 ASD patients (Age: 48 +/- 23 y; mFI:.4 +/-.7; Levels fused: 10.3 +/- 4.1), lumbosacral fractional curve > 10degree, mean followup 39.5 months, were divided into 2 groups: PSF alone (PSF, n=382) and interbody fusion (IBF, n=210; ALIF: 31, TLIF: 179). Outcomes evaluated were fractional curve correction, overall deformity correction and rates of revision surgery for pseudarthrosis or rod fracture at the lumbosacral junction.
RESULT(S): A significantly greater number of patients in the IB cohort had underlying osteoporosis (63% versus 33%, p < 0.001); otherwise, there were no significant difference in patient comorbidities. There was significantly greater EBL (2.3 L vs. 1.3 L, p < 0.0001), intraoperative pRBCs transfused (2.3 U vs. 1.3 U, p < 0.001), and longer operative time (7.1 vs. 6.3 hours, p < 0.0001) in the IBF group compared with PSF. Both groups had similar magnitude of fractional curve correction (7.0 +/-7.1degree in IB vs. 6.3 +/- 6.9degree in PSF, p=0.26) and final coronal alignment (23.5 mm vs. 19.8 mm, p=0.08). Patients in the IBF group had a higher magnitude of SVA change (-30.6 mm vs -19.5 mm, p < 0.05) and increase in lumbar lordosis (11.5degree vs 5.6degree, p < 0.001). There was no difference in the rate of revision surgery at minimum 2-year followup for rod fracture, pseudarthrosis, or any instrumentation related complication. Sub-analysis demonstrated that there were no significant differences in magnitude of fractional curve correction, or improvement in lumbar lordosis, coronal, or sagittal alignment in the ALIF group compared to the TLIF group. There was no significant impact of number of levels at which a lumbar interbody fusion was performed on the degree of fractional curve correction.
CONCLUSION(S): At minimum 2-year followup, patients had comparable fractional curve and coronal alignment correction when treated with interbody fusion at L4-S1 versus posterior fusion alone. There was no difference in rod fracture and pseudarthrosis rates at 2-year followup. These data suggest that utilization of interbody technique at the lumbosacral junction is not clearly superior to posterior fusion alone for treatment of the fractional curve. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

Orthopedic surgeons play a pivotal role in developing ways to practically and safely integrate new technology into their surgical workflow with the aim of improving safety, efficiency, and clinical outcomes. Interest in augmented reality applications to orthopedic surgery has grown significantly in the last decade due to a desire to limit complications and improve procedural efficiency. However, despite this technology remaining in its infancy, it is now emerging from proof of concept toward clinical use. This review provides a history and brief overview of the different applications of this technology in order to critically appraise its potential usefulness as its becomes more widespread.

BACKGROUND:Adult spinal deformity (ASD) surgery can entail complex reconstructive procedures. It is unclear whether there is any effect of case start time on outcomes. We sought to evaluate the effects of case start time and day of the week on 90-day complication, readmission, and revision rates after ASD surgery. METHODS:This is a retrospective study of 1040 ASD patients from a single institution. We collected start times and day of the week for cases from 2011 to 2018. Early start was designated as any case starting either before or at 7:30 am or between 7:30 and 11 am; late start was designated as any case starting at 11 am or later. Outcome measures include 90-day complication, revision, and readmission rates. RESULTS:= 0.046). CONCLUSIONS:A late OR start time was predictive of increased risk for neurologic complication, 90-day readmission, and unplanned reoperation. The well-established protocols for first start OR times for elective ASD surgery may decrease outcome risk and reduce variability in complication rates. CLINICAL RELEVANCE/CONCLUSIONS:Understanding the impact of start time on outcomes and complications after ASD surgery is helpful for surgeons in preoperative planning and for institutions and hospitals' allocation of operating room staff and resources. LEVEL OF EVIDENCE/METHODS:3.

STUDY DESIGN/METHODS:Retrospective review of a single-center spine database. OBJECTIVE:Investigate the intersections of chronological age and physiological age via frailty to determine the influence of surgical invasiveness on patient outcomes. SUMMARY OF BACKGROUND DATA/BACKGROUND:Frailty is a well-established factor in preoperative risk stratification and prediction of postoperative outcomes. The surgical profile of operative adult spinal deformity (ASD) patients who present as elderly and not frail has yet to be investigated. Our aim was to examine the surgical profile and outcomes of ASD patients who were not frail and elderly. METHODS:Included: ASD patients≥18 years old, ≥4 levels fused, with baseline(BL) and follow up data. Patients were categorized by ASD frailty index: Not Frail[NF], Frail[F], Severely Frail [SF]. An elderly patient was defined as ≥70 years. Patients were grouped into NF/elderly and F/elderly. SRS-Schwab modifiers were assessed at baseline and 1-year(0, +, ++). Logistic regression analysis assessed the relationship between increasing invasiveness, no reoperations, or major complications, and improvement in SRS-Schwab modifiers[Good Outcome]. Decision tree analysis assessed thresholds for an invasiveness risk/benefit cutoff point. RESULTS:598 ASD pts included(55.3yrs, 59.7%F, 28.3 kg/m2). 29.8% of patients were above age 70. At baseline, 51.3% of patients were NF, 37.5% F, and 11.2% SF. 66(11%) of patients were NF and elderly. 24.2% of NF-Elderly patients improved in SRS-Schwab by 1-year and had no reoperation or complication postoperatively. Binary regression analysis found a relationship between worsening SRS-Schwab, postop complication, and reoperation with invasiveness score(OR: 1.056[1.013-1.102], p = 0.011). Risk/benefit cut-off was 10(p = 0.004). Patients below this threshold were 7.9[2.2-28.4] times more likely to have a Good Outcome. 156 patients were elderly and F/SF with 16.7% having Good Outcome, with a risk/benefit cut-off point of <8 (4.4[2.2-9.0], p < 0.001). CONCLUSIONS:Frailty status impacted the balance of surgical invasiveness relative to operative risk in an inverse manner, while the opposite was seen amongst elderly patients with a frailty status less than their chronologic age. Surgeons should perhaps consider incorporation of frailty status over age status when determining realignment plans in patients of advanced age.Level of Evidence: ???

BACKGROUND:Interbody fusion at the caudal levels of long constructs for adult spinal deformity (ASD) surgery is used to promote fusion and secure a solid foundation for maintenance of deformity correction. We sought to evaluate long-term pseudarthrosis, rod fracture, and revision rates for TLIF performed at the base of a long construct for ASD. METHODS:We reviewed 316 patients who underwent TLIF as a component of ASD surgery for medical comorbidities, surgical characteristics, and rate of unplanned reoperation for pseudarthrosis or instrumentation failure at the TLIF level. Fusion grading was assessed after revision surgery for pseudarthrosis at the TLIF level. RESULTS:Rate of pseudarthrosis at the TLIF level was 9.8% (31/316), and rate of rod fractures was 7.9% (25/316). The rate of revision surgery at the TLIF level was 8.9% (28/316), and surgery was performed at a mean of 20.4 ± 16 months from the index procedure. Current smoking status (odds ratio 3.34, P = 0.037) was predictive of pseudarthrosis at the TLIF site. At a mean follow-up of 43 ± 12 months after revision surgery, all patients had achieved bony union at the TLIF site. CONCLUSIONS:At 3-year follow-up, the rate of pseudarthrosis after TLIF performed at the base of a long fusion for ASD was 9.8%, and the rate of revision surgery to address pseudarthrosis and/or rod fracture was 8.9%. All patients were successfully treated with revision interbody fusion or posterior augmentation of the fusion mass, without need for further revision procedures at the TLIF level.