Faculty Bibliography

BACKGROUND:Accounting for less than 0.4% of disc herniations, intradural lumbar disc herniations (ILDHs) are a rare occurrence primarily described as a complication after lumbar spine surgery. It is speculated that the herniation may propagate intradurally from either an unrecognized dural defect after initial surgery or as a result of adhesions between the dura and posterior longitudinal ligament. This report explores the etiology, presentation, diagnostic evaluation, and treatment of ILDH along with a case report and microsurgery video. OBSERVATIONS/METHODS:A 67-year-old patient who 1 year earlier had undergone an L2-5 laminectomy and L2-3 decompression with no known complications presented with low back pain and radiating right leg, buttock, and groin pain for 1 month. Physical examination indicated no numbness or weakness. Magnetic resonance imaging demonstrated a large ILDH. A transforaminal interbody fusion was performed followed by a durotomy, ILDH removal, and dural closure. A ventral dural defect was found and repaired during the procedure. LESSONS/CONCLUSIONS:The treatment for ILDH is laminectomy with dorsal durotomy. Because ILDH has rarely been described in literature, understanding its presentation is crucial for prompt identification and management.

OBJECTIVES/OBJECTIVE:Cervical deformity morphotypes based on type and location of deformity have previously been described. This study aimed to examine the surgical strategies implemented to treat these deformity types and identify if differences in treatment strategies impact surgical outcomes. Our hypothesis was that surgical strategies will differ based on different morphologies of cervical deformity. METHODS:Adult patients enrolled in a prospective cervical deformity database were classified into four deformity types (Flatneck (FN), Focal kyphosis (FK), Cervicothoracic kyphosis (CTK) and Coronal (C)), as previously described. We analyzed group differences in demographics, preoperative symptoms, health-related quality of life scores (HRQOLs), and surgical strategies were evaluated, and postop radiographic and HROQLs at 1+ year follow up were compared. RESULTS:< 0.05) with their respective surgical strategies. CONCLUSIONS:The four types of cervical deformities had different surgical strategies to achieve improvements in HRQOLs. FN and FK types were more often treated with APSF surgery, while types CTK and C were more likely to undergo PSF. CTK deformities had the highest number of 3COs. This information may provide guidelines for the successful management of cervical deformities.

Objective/UNASSIGNED:The objective of the study is to investigate which neurologic complications affect clinical outcomes the most following cervical deformity (CD) surgery. Methods/UNASSIGNED:CD patients (C2-C7 Cobb >10°, CL >10°, cSVA >4 cm or chin-brow vertical angle >25°) >18 years with follow-up surgical and health-related quality of life (HRQL) data were included. Descriptive analyses assessed demographics. Neurologic complications assessed were C5 motor deficit, central neurodeficit, nerve root motor deficits, nerve sensory deficits, radiculopathy, and spinal cord deficits. Neurologic complications were classified as major or minor, then: intraoperative, before discharge, before 30 days, before 90 days, and after 90 days. HRQL outcomes were assessed at 3 months, 6 months, and 1 year. Integrated health state (IHS) for the neck disability index (NDI), EQ5D, and modified Japanese Orthopaedic Association (mJOA) were assessed using all follow-up time points. A subanalysis assessed IHS outcomes for patients with 2Y follow-up. Results/UNASSIGNED:= 0.263, 0.163). Conclusions/UNASSIGNED:18% of patients undergoing CD surgery experienced a neurologic complication, with 15% within 3 months. Patients who experienced any neurologic complication had worse mJOA recovery kinetics by 1 year and trended toward worse recovery at 2 years. Of the neurologic complications, central neurologic deficits and spinal cord deficits were the most detrimental.

BACKGROUND:There is controversy as to whether fusions should have the upper instrumented vertebrae (UIV) end in the upper lumbar spine or cross the thoracolumbar junction. This study compares outcomes and reoperation rates for thoracolumbar fusions to the sacrum or pelvis with UIV in the lower thoracic versus lumbar spine to determine if there is an increased reoperation rate depending on UIV selection. METHODS:A retrospective review of prospectively collected data was conducted from a single-center database on adult patients with degeneration and deformity who underwent primary and revision fusions with a caudal level of S1 or ilium between 2012 and 2018. Fusions were classified as anterior, posterior, or combination approach. Revision fusions included patients who had spinal surgery at another institution prior to their revision surgery at the center. Patients were categorized into 1 of 3 groups based on UIV: T9-T11, upper lumbar region (L1-L2), and lower lumbar region (L3-L5). Inclusion criteria were age 18 years or older and at least 1 year of clinical follow-up. Patients were excluded from analysis if they had tumors, infections, or less than 1 year of follow-up after the index procedure. RESULTS:= .002) from the reoperation rates for the same diagnoses in the upper lumbar spine (4.6% and 1%) or lower lumbar spine (6.2% and 0%). A multivariate logistical regression model at 2-year follow up did not show a statistically significant difference between reoperation rates between the thoracic and upper lumbar spine UIV groups. CONCLUSION/CONCLUSIONS:Constructs with UIV in the thoracic spine suffer from higher rates of proximal junctional kyphosis and pseudoarthrosis, whereas those with UIV in the upper lumbar spine have higher rates of adjacent segment disease. Given this tradeoff, there is no certain recommendation on what UIV will result in a lower reoperation rate in thoracolumbar fusion constructs to the sacrum or pelvis. Surgeons must evaluate patient characteristics and risks to make the optimal decision.

Robotic-assisted adult deformity surgery has played a rapidly expanding role since its introduction. As robotic spine technologies improve, the potential to limit complications and morbidity is vast. The improvements in instrumentation accuracy combined with the ability to maintain that accuracy in multiple positions allow creative surgical approaches and techniques that can limit operative time, blood loss, and improve outcomes. In the years to come, robotic-assisted spine surgery and navigation will likely play an expanding role that continues to be defined. LEVEL OF EVIDENCE: 5, expert opinion.

STUDY DESIGN/METHODS:Retrospective cohort analysis. OBJECTIVE:To compare outcomes of plastic versus spine surgeon wound closure in revision 1 to 4 level thoracolumbar fusions. SUMMARY OF BACKGROUND DATA/BACKGROUND:Plastic surgeons perform layered musculocutaneous flap closures in high-risk spine patients such as revision posterior spinal fusion and complex deformity correction surgeries. Few studies have assessed outcomes of revision fusion performed with plastic surgical closures, particularly in nondeformity thoracolumbar spinal surgery. METHODS:A retrospective review of 1 to 4 level revision thoracolumbar fusion performed by Orthopedic or Neurosurgical spine surgeons. Patient charts were reviewed for demographics and perioperative outcomes. Patients were divided into two cohorts: wound closures performed by spine surgeons and those closed by plastic surgeons. Outcomes were analyzed before and after propensity score match for prior levels fused, iliac fixation, and levels fused at index surgery. Significance was set at P < 0.05. RESULTS:Three hundred fifty-seven (87.3%) spine surgeon (SS) and 52 (12.7%) plastic surgeon (PS) closures were identified. PS group had significantly higher number of levels fused at index (PS 2.7 ± 1.0 vs. SS 1.8 ± 0.9, P < 0.001) and at prior surgeries (PS 1.8 ± 1.2 vs. SS 1.0 ± 0.9, P < 0.001), and rate of iliac instrumentation (PS 17.3% vs. SS 2.8%, P < 0.001). Plastics closure was an independent risk factor for length of stay  > 5 days (odds ratio 2.3) and postoperative seroma formation (odds ratio 7.8). After propensity score match, PS had higher rates of seromas (PS 36.5% vs. SS 3.8%, P < 0.001). There were no differences between PS and SS groups in surgical outcomes, perioperative complication, surgical site infection, seroma requiring aspiration, or return to operating room at all time points until follow-up (P > 0.05 for all). CONCLUSION/CONCLUSIONS:Plastic spinal closure for 1 to 4 level revision posterior thoracolumbar fusions had no advantage in reducing wound complications over spine surgeon closure but increased postoperative seroma formation.Level of Evidence: 4.

BACKGROUND CONTEXT: Cervical deformity (CD) surgery can markedly improve patient quality of life. The longevity of CD correction and the mechanism of alignment deterioration are not well understood. PURPOSE: To investigate preoperative risk factors and failure mechanisms that erode CD corrections and the impact on functional outcomes. STUDY DESIGN/SETTING: Retrospective review of a prospective CD database. PATIENT SAMPLE: This study included 155 operative CD patients with baseline (BL) and 1-year follow-up. OUTCOME MEASURES: Alignment at baseline, 3 months, 6 months and 1 year: cervical sagittal vertical axis (cSVA), C2 Slope (C2S), T1 slope (T1S), C2-C7 lordosis (CL), T1S-CL mismatch (TS-CL), Neck Disability Index (NDI), Modified Japanese Orthopaedic Association score (mJOA).
Method(s): A retrospective review of a prospective database of operative CD patients was analyzed. Patients with baseline, 3-month, 6-month and 1-year cervical radiographs were included. Cervical sagittal vertical axis (cSVA) <4cm was used to categorize patients as well-aligned vs malaligned. Additionally, three subsets were defined as follows: (1) patients who were malaligned preoperatively (cSVA>=4) and remained well aligned at 1 year postoperatively; (2) patients who were well-aligned but experienced alignment deterioration (cSVA>=4cm) up to 1 year postop, and; (3) patients who never attained cSVA <4cm. These groups were compared in terms of demographic factors, surgical factors, baseline radiographic parameters and radiographic and surgical outcomes at baseline and 1 year, using t-tests and X2 tests for continuous and categorical variables, respectively.
Result(s): A total of 155 patients were included (mean age 61.41, 60.9% F). The entire cohort was analyzed at all time points for alignment using cSVA. Among 89 patients with X-rays at every time point, 30 patients (34%) maintained their good alignment correction at 1-year postop. Seventeen patients (19%) experienced alignment deterioration and 42 patients (46%) never reached cSVA <4cm at any time point. Four patients lost their correction at 3 months, 6 patients at 6 months and 8 patients were malaligned by 1 year. The never-aligned cohort was significantly older when compared to those who maintained alignment or those who deteriorated (65.9 vs 61.8 vs 58.8, p=0.038). Patients who never achieved good alignment and those who suffered deterioration had a significantly higher rate of DJK (42.9% vs 47.1% vs 3.3%, p=0.001). Other failure mechanisms in the deterioration group included loss of subjacent spinopelvic compensation and PJK. At baseline, patients with alignment deterioration had a smaller cSVA compared to those who maintained or never reached good alignment (40.5 vs 52.0 and 60.1mm, p=0.001), and less TK (-43.4 vs -55.9 vs -61.4, p=0.049). At 1-year postop, patients with deterioration had worsening of their mJOA score at 6 months compared to those who maintained or never reached proper alignment (2.50 vs 0.04 vs 1.20, p=0.032). There were no significant differences in smokers, BMI, frailty, osteoporosis, levels fused, UIV, LIV, EBL, operative time, rod diameter, rod material, utilization 3-column osteotomy, mean osteotomy grade, in construct (fused) loss of alignment or revision rate between the groups (all p>.05)
Conclusion(s): Cervical deformity correction surgery failed to achieve acceptable sagittal alignment in 46% of patients. In those with successful correction, 36% suffered alignment deterioration within 1 year. Distal junctional kyphosis was the most common failure mechanism leading to loss of correction. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: Robot-guided lumbar instrumented fusion (RGLF) for accurate pedicle screw placement is increasingly popular. Learning curve (LC) has been reported to be short, but simple comparison of a set number of early to later cases may oversimplify the LC. This study offers an analysis of a single institution LC for RGLF as it relates to increasing case complexity as determined by Spine Surgical Invasive Index (SII) as described by Mirza, and advanced techniques. PURPOSE: To determine if RGLF is related to SII and is more dynamic than previously described. STUDY DESIGN/SETTING: Single-center retrospective cohort study. PATIENT SAMPLE: A total of 346 patients undergoing RGLF at a single institution from 2018 to 2021. OUTCOME MEASURES: Case complexity indicators (levels fused, SII, iliac fixation, single position surgery), radiation dose, procedure/operative time (PTime/OpTime), EBL, LOS, failed registration, robotic mechanical failures, perioperative complications and OR returns.
METHOD(S): All RGLFs at a single institution were included. Outcome measures indicating case complexity (levels fused, SII, iliac fixation, single position surgery) underwent regression analysis to determine risk factors for robot-related complications. Peaks in these characteristics over the course of 346 cases were identified. Outcomes including radiation dose, procedure/operative time (PTime/OpTime), EBL, LOS, failed registration, robotic mechanical failures, perioperative complications, and returns to OR were analyzed in stepwise fashion by each consecutive case using independent samples t-tests and chi-squared analyses as appropriate.
RESULT(S): A total of 346 RGLFs included. No significant changes in demographics over time. SII was an independent risk factor for robot registration and intraoperative mechanical failures on multivariate regression analysis (p<0.001). SII had significant peaks between 10 to 20 cases and 165 to 330 cases. The following outcomes were overcome during a first LC corresponding to an early SII peak: PTime (401.2+/-135.6 vs 361.4+/-99.7 min; p= 0.047), OpTime (326.0+/-129.4 vs 279.4+/-91.9 min; p= 0.034), robot mechanical failures (26.7% vs 10.1%; p=0.046), all postop complications (60.0% vs 29.2%; p=0.037), ileus (9.0% vs 3.3%; p=0.046), urinary complications (6.4% vs 1.9%; p=0.043). A later LC corresponding to a second SII peak saw significant changes in PTime per level (291.1+/-84.7 vs 259.5+/-108.5 min; p=0.017), OpTime per level (223.6+/-70.4 vs 200.9+/-90.7 min; p= 0.038), EBL (316.7+/-264.0 vs 247.4+/-204.6 mL; p=0.035), LOS (3.8+/-2.2 vs 2.7+/-1.1 days; p=0.001), all intraoperative complications (23.8% vs 13.2%; p=0.036), surgical site infections (2.54% vs 10.34%; p=0.022), robot registration failures (8.3% vs 2.1%; p=0.039), new neurological deficits (5.2% vs 0.0%; p=0.050), instrumentation failures (1.7% vs 3.7%; p =0.043), and returns to OR for pedicle screw revision (1.2% vs 8.9%; p=0.046) or for neurological deficit (3.9% vs 0.0%; p=0.050).
CONCLUSION(S): Two learning curves were observed that mirrored significant peaks in SII. The second, more significant, wave of complications was observed with increased surgical complexity. This suggests a longer, more dynamic learning curve than has been previously described. Avoiding surgeries with high SII at the beginning of RGLF experience may prevent early complications. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: Both frailty and surgical invasiveness are correlated with increased risk of complications following ASD surgery, yet there is no accepted risk-stratification system combining these factors. PURPOSE: The aim of this study is to ascertain data-driven categories defining the risk for 90-day complications following ASD surgery based on frailty and surgical invasiveness. STUDY DESIGN/SETTING: Retrospective review of a multicenter database. PATIENT SAMPLE: A total of 1,272 surgical ASD patients undergoing spinal fusions >=5 levels OUTCOME MEASURES: Ninety-day complication risk, 90-day complication rate, invasiveness thresholds for increased complications.
METHOD(S): Using a prospective, multicenter database, we identified 1,272 surgical ASD patients undergoing posterior spinal fusion of at least five levels. Patients were separated into three frailty groups based on the ASD-FI frailty index. Within each frailty group, stratum-specific likelihood ratio (SSLR) analyses were performed to define frailty-based surgical invasiveness cutoffs associated with increased risk for 90-day complications. Cutoffs generated through SSLR were confirmed with multivariable logistic regression analysis controlling for age, alignment, and ODI.
RESULT(S): Mean age was 60 +/- 14 years, 74% females. Of 1,272 surgical ASD patients, 319 (35%) were nonfrail (NF), 667 (52%) frail (F), and 286 (23%) severely frail (SF). Mean SI was 93 +/- 35. The mean complication rate was 35.4% for NF, 37% for F and 43.6% for SF. SSLR analysis of NF patients produced 2 complication categories: 33% complication rate for SI < 153 and 73% for SI >= 153. NF patients with SI >= 153 had 4.14x higher odds of complications than NF patients with SI <153 (p=0.04). SSLR analysis of F patients produced 3 complication categories: 26% complication rate for SI < 60, 42% for SI of 60 to 179, and 64% for SI >= 180. Relative to F patients with SI < 60, F patients with SI 60 to 179, and SI >= 180 had 2.4x and 6.7x higher odds of complications, respectively (p<0.01 for both). SSLR analysis of SF patients produced 2 complication categories: 35% complication rate for SI < 82 and 49% complication rate for SI >= 82. SF patients with SI >= 82 had 1.77x higher odds of complications than SF patients with SI < 82 (p=0.04).
CONCLUSION(S): Frailer groups were found to have lower SI cutoffs, indicating the less invasiveness surgeries can be performed on frail patients to minimize complication risk. This risk-stratification system is useful for counselling patients regarding their risk of complication. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright

BACKGROUND CONTEXT: A previous study utilized normative alignment to determine overcorrections and predict mechanical complications in adult spinal deformity (ASD) surgery. Other studies have recommended alignment targets that optimize age-appropriate physical function. The difference in functional outcomes and mechanical complications between these prescribed alignment targets has not been explored. This study utilizes a component angle of the T1 pelvic angle (TPA) within the fusion to compare normative and age-pelvic incidence (PI) optimal alignment in terms of proximal junctional kyphosis (PJK), proximal junctional failure (PJF) and health related quality of life measures (HRQL). Using the component of TPA within the fusion, the T4-pelvic angle (T4PA), allows for the measurement spinopelvic alignment separate from that of the unfused thoracic spine and any PJK that may occur postoperatively. PURPOSE: To compare ASD patients corrected to normative alignment vs age-PI optimal alignment in terms of PJK/PJF and outcomes. STUDY DESIGN/SETTING: Retrospective analysis of a prospective multicenter ASD database and a database of asymptomatic subjects. PATIENT SAMPLE: This study included 1,916 ASD patients and 118 asymptomatic subjects for formula development; 288 ASD patients with 2-year X-ray and HRQL follow-up. OUTCOME MEASURES: SF36-PCS, ODI, SRS-22, NRS back/leg, PJK (change in UIV to UIV+2 >10degree), PJF (defined as severe PJK with change >21.6degree, or UIV olisthesis, or proximal junctional fracture).
METHOD(S): Baseline relationships between age, PI and T4PA, were analyzed in the ASD patients and compared to the asymptomatic subjects. Linear regression modeling was used to determine alignment based on PI and age in asymptomatic subjects (normative alignment), and in ASD patients, alignment corresponding to age-appropriate functional status (optimal alignment). ASD patients with UIV above T4 were grouped based on their corrections: normative vs optimal. Extreme over or under corrected patients were excluded (greater than or less than 2SD from mean postop T4PA). For each group, the rate of PJK and PJF were determined.
RESULT(S): In the multilinear regression analysis of the 119 asymptomatic subjects, T4PA correlated with age and PI, r=.713, p<.0001. 1916 ASD patients were included in the optimal formula development. In the 288 ASD patients included in the pre- to postop analysis (137 normative, 151 optimal), there was no difference in baseline alignment or HRQL between the groups. At 6 weeks, the normative aligned group had smaller T4PA (4.45 vs 14.1) and PI-LL (-7.24 vs 7.4), all p<.0001. Normative aligned patients had the higher PJK rate (40% vs 27.2%, p=.03) compared with optimal; and a higher PJF rate (17% vs 6.8%, p=.008). PJF patients had -1.2degreeof T4PA offset from normative alignment and -5.2degreeof offset from optimal alignment. By contrast, no PJF patients had 3.8degree of T4PA offset from normative alignment and -0.42degree of offset from optimal alignment. There was a trend toward worse 2-year SF36-PCS in patients who suffered PJF (37.7 vs 41.6, p=.09). Both the Normative and Optimal groups improved in outcomes from baseline to 2-year (p<.001) with no difference in 2-year HRQL.
CONCLUSION(S): Correcting ASD patients to normative alignment resulted in higher rates of PJK and PJF without improvements in HRQL. ASD patients should not be corrected to match the alignment of their asymptomatic unfused peers, rather they should be realigned optimally to match age-appropriate physical function. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Copyright