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 alignment and cervical deformity surgery are complex topics. Recently, a score inspired by work on thoracolumbar alignment was developed for cervical alignment (cervical deformity score, CDS). While this score was designed to predict early mechanical failures, its association with patient reported outcomes (PROM) remains unclear. PURPOSE: Investigate the association between PROM, complications, and a newly described cervical deformity score. STUDY DESIGN/SETTING: Retrospective review of prospective multicenter database. PATIENT SAMPLE: A total of 102 adult cervical deformity (CD) patients with at least 1 year follow-up. OUTCOME MEASURES: NDI, neck pain, EQ5D, complication rates.
Method(s): CD patients with baseline and 1-year follow-up were included. Postoperative CDS was constructed using offset from age-adjusted values: SVA [(age -55)*2+25], T1 Slope [(age -55)/4 + 28.7], and TS minus CL [cst: between 26.5 and 14.5degree]. Points were assigned based on the offset from alignment targets and the CDS was the sum of the three individual scores. Association with patient-reported outcomes was investigated using Pearson's correlations. Comparison of CDS between patients with and without complication within 1-year was conducted. Logistical regression controlling for demographic and comorbidities was conducted to identify if CDS was an independent predictor of complications.
Result(s): A total of 102 patients met inclusion criteria (61.7yo+/-10, 66.7% F); 37.6% of them had a history of previous cervical surgery (16.7% previous ACDF, 11.7% previous posterior fusion). Preoperatively, they had elevated disability (NDI: 47.1+/-18.1), pain (NSR Neck: 6.6+/-2.5), myelopathy (mJOA: 13.6+/-2.7) and lower general health (EQ5D: 0.74+/-0.07). They also presented with an overall cervical kyphotic alignment (C2-C7: -6.3degree+/-20.9), a moderate cervical anterior alignment (cSVA: 39mm+/-20; TS-CL: 37.9degree+/-19.4) and a posterior global thoracolumbar alignment (SVA: -3mm+/-68). The median of number of levels fused was 7 [4-9], with 49% treated with a posterior approach and 30.4% with a combined approach; 83.2% received an osteotomy, 44.6% some posterior osteotomy, 16.8% grade 6 or 7. The mean operative time was 368min+/-208, median EBL was 525cc [200 1025], and LOS was 5 days [4 8]. At 1 year, patients improved significantly in terms of disability (NDI: 36.2+/-20.7, 60.8% reached MCID), pain (NSR: 4.1+/-2.9) and general health (EQ5D: 0.79+/-0.08) (all p<0.001). The cervical alignment significantly changed (C2-C7: 7.8+/-14.5m; cSVA: 34mm+/-15; TS-CL: 28.9degree+/-12.6 all p <0.002), with a 1-year CDS of 1.68+/-2.46 (prctl [0 3.25]). There was a significant association between increased CDS and increased disability (r=0.273), pain (r=0.336) and lower general health (r=-0.283). Patient with a lower disability level (NDI<20) had a significantly lower CDS (0.71+/-2.3 vs 2.16+/-2.4 p<0.004). Patients without any complications before 1 year had a lower CDS (0.78+/-2.33 vs 2.18+/-2.40 p=0.005), as did patients without major complications (1.36+/-2.27 vs 2.50+/-.78 p=0.037). Deeper analysis revealed significant differences in terms of CDS for patients experiencing cardiopulmonary, instrumentation and radiographic complications (p<0.05). Multivariate analysis, controlling for age and comorbidities, show 1-year CDS to be a significant predictor of complication (p=0.002, OR=1.409).
Conclusion(s): With better outcomes and lower complication rate, maintaining a proportionate alignment postoperatively can result in superior outcomes following CD surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Robot-guided lumbar instrumented fusion (RGLF) has the potential to improve safety and accuracy of pedicle screw placement. However, there are pitfalls in adopting this new technology and, as in adopting any new OR technology, there may be early complications. Optimizing workflow by avoiding interbody placement prior to pedicle screws placement (interbody-first workflow, IFW) and using caution in patients with poor bone quality (L1 Hounsfield units [HU] under 148) may improve outcomes. PURPOSE: To determine risk factors for robot-related complications and suggest optimal OR workflow. STUDY DESIGN/SETTING: Single-center retrospective study. PATIENT SAMPLE: A total of 344 RGLF cases from 2018 to 2021. OUTCOME MEASURES: L1 and UIV HU, levels fused, L5-S1 inclusion, interbody placed first workflow (IFW), hyperlordotic interbody, robot registration method, robot registration failure, intraoperative robot mechanical failures and pedicle screw malpositioning.
METHOD(S): Retrospective analysis of RGLFs at a single institution. Univariate analysis with t-tests, Mann-Whitney U tests, or chi-squared analysis assessed demographics, L1 and UIV HU, levels fused, L5-S1 inclusion, IFW, hyperlordotic cage, and robot registration method as risk factors for robot registration failure, intraoperative robot mechanical failures, and pedicle screw malpositioning. Multivariate logistic regression of risk factors approaching or achieving significance was conducted. A receiver operating characteristic (ROC) curve was created to determine a threshold for independent risk factors.
RESULT(S): A total of 344 RGLFs were included. In registered vs registration failure cases, smoking (12.73% vs 28.57%; p=0.041), L1HU (139.81+/-46.86 vs 177.16+/-55.74; p=0.009), L5-S1 inclusion (50.00% vs 80.95%; p=0.006), and IFW (58.07% vs 85.71%; p=0.014) were significant risk factors on univariate analysis. On multivariate analysis, smoking (p=0.003), L1HU (p=0.006), and L5-S1 inclusion (p=0.022) were independent risk factors and IFW approached significance (p=0.099) for risk of registration failure. In successful vs all robot failures cases, age (55.72+/-13.38 vs 59.92+/-11.38 years; p=0.046), female gender (48.70% vs 69.44%; p=0.018), levels fused (1.37+/-0.63 vs 1.67+/-0.76; p=0.010), L5-S1 inclusion (50.00% vs 69.44%; p=0.027), and IFW (57.47% vs 77.78%; p=0.012) were significant risk factors on univariate analysis. On multivariate analysis, female gender (p=0.047) and L5-S1 inclusion (p=0.049) were independent risk factors and IFW approached significance (p=0.055) for risk of mechanical failure. In successful vs pedicle screw malpositioned cases, IFW was a significant independent risk factor for pedicle screw malpositioning on multivariate analysis (p=0.038). On subanalysis of 124 robot-guided anterior-posterior lumbar fusion (RG APLF), L1 HU was an independent risk factors for registration failure (p=0.007) and approached significance for mechanical failures (p=0.051). ROC analysis revealed a cutoff of L1 HU of 148.55 for mechanical failures (area under the curve = 0.778). Levels fused (1.41+/-0.69 vs 2.00+/-0.54; p=0.018) was a significant risk factor for pedicle screw malpositioning on univariate analysis.
CONCLUSION(S): In all RGLFs, IFW was a risk factor for robot-related complications. In RG APLF, low L1 HU was a risk factor. Robot-related complications may be avoided by placing pedicle screws prior to interbody and by using caution in patients with poor bone quality. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult spinal deformity (ASD) surgery is costly and carries a high complication rate. It is therefore very important to optimize value (cost-per-QALY) or cost-utility in ASD surgery. To identify targets for improvement, we compared the influence of patient factors, measured by frailty, vs surgical factors, measured by surgical invasiveness (SI), on 2-year cost-utility. Patient frailty is an approximation of baseline patient health status, whereas SI represents extensiveness of the surgical intervention. Data comparing the relative importance of these aggregate measures on cost-utility are limited. Additionally, this analysis can serve to help identify the most impactful modifiable factors in the value equation. PURPOSE: The aim of this study was to assess whether frailty or SI is a more important determinant of 2-year cost-utility in ASD surgery. STUDY DESIGN/SETTING: Prospective, multicenter study. PATIENT SAMPLE: ASD patients with >4-level fusion and eligible for minimum 2-year follow-up were included. OUTCOME MEASURES: Two-year cost-per-QALY.
METHOD(S): Index and total episode of care (EOC; iEOC; tEOC) cost was calculated using Medicare's inpatient prospective payment system (IPPS) for MS-DRGs 453-460. All costs were adjusted for inflation to 2020 US dollar values. QALYs gained were calculated using baseline, 1-year, and 2-year SF-6D scores. A discount rate of 3% was assumed. Cost-per-QALY was determined by calculating total EOC per cumulative QALY at two years. Patients were categorized as not-frail (NF, <0.3), frail (F, 0.3<= to <0.5), and severely frail (SF, >0.5). SI was categorized as low-SI (SI<90) and high-SI (SI>90). A generalized linear model with gamma error distribution and log link was used to estimate the association between frailty and SI on cost-per-QALY. All analyses were controlled for gender and blood loss. Other variables commonly adjusted for (ie, age, levels fused) were intentionally not controlled for in this analysis to avoid collinearity with either frailty or SI.
RESULT(S): DRG data for index and revision surgery was available for 505/889 patients. Mean age was 62.5+12.4years, 76% were women, and 91% were Caucasian. Of the total patients,72% demonstrated positive gain in QALY at 2 years (0.12+0.09, p<0.001) compared to baseline. The mean iEOC was $72,717, tEOC was $86,066, and cost-per-QALY was $52,357. Eighty-nine patients had 114 (range 1-5) revisions (17.6%) compared to 416 without. The tEOC in revision group was $151,913 compared to $71,978 in the non-revision group with 2-year cost-per-QALY 98,262 compared to 42,537, respectively. On adjusted analysis, F and SF patients compared to NF patients had significantly higher cost-per-QALY (p<0.0001 for all comparisons) regardless of the surgical invasiveness. However, SI was not significantly associated with cost-per-QALY regardless of patient's frailty.
CONCLUSION(S): Increasing levels of frailty were associated with significantly and incrementally higher values of 2-year cost-per-QALY in both low and high SI groups. However, within each frailty group, the high and low SI groups had equivalent cost-per-QALY. Frailty appears to be a better determinant of 2-year cost-per-QALY compared to surgical invasiveness. Surgeons should place more importance on modifiable patient factors compared to surgical factors to improve or optimize 2-year cost-utility in ASD surgery. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: ASD surgery is associated with postoperative improvements in patient pain and function but is also associated with high complication rates and long recovery. Accordingly, if given a choice, patients may indicate they would not undergo surgery again. PURPOSE: At minimum two years postop, evaluate 1) surgically treated ASD patients for willingness to receive/not receive the same surgery, 2) surgeon willingness to perform/not perform the same surgery, 3) surgeon opinion if the corresponding patient would indicate they would/would not have the same surgery again. STUDY DESIGN/SETTING: Analysis of patient vs surgeon willingness to perform/receive surgery for ASD patients enrolled into a prospective, multicenter study. PATIENT SAMPLE: Surgically treated ASD patients prospectively enrolled into multicenter study. OUTCOME MEASURES: Numeric rating scale (NRS) back and leg pain, Scoliosis Research Society-22r questionnaire (SRS-22r), Short Form-36v2 questionnaire (SF-36), Oswestry Disability Index (ODI), estimated blood loss, duration of hospital stay, postoperative complications, revision spine surgery, patient and surgeon willingness to perform surgery.
Method(s): Surgically treated ASD patients, prospectively enrolled into a multicenter study from 2009-2018, were asked at minimum 2 years postop, using SRS-22r question 22 if, based upon their surgical and recovery experience, they would undergo the same surgery. Surgeons were matched to their corresponding patients and the surgeons asked if 1) surgeon would perform the same surgery on the patient and why/why not, 2) surgeon believed the patient would undergo the same surgery and why/why not. Patients were divided into those that indicated they would (yes) or not (no) have same surgery. Agreement between patient and surgeon willingness for same surgery was assessed and correlations between willingness for same surgery and postop complications, deformity improvement, and PROMs evaluated.
Result(s): Of 961 patients eligible for study, 580 were evaluated. The no group (n=108, 18.6%) had similar levels fused, osteotomies, duration of hospital and SICU stay, and major complications as the yes group. (n=472; 81.4%; p>0.05). No group members were younger (58.5 vs 61.6 years), more frail (ASD frailty scale 3.9 vs 3.3), and at minimum 2-years postop had more complications requiring surgery and worse postop improvements for all PROMs including ODI (3.8 vs 18.9), SF-36 PCS (1.8 vs 10) and SRS-22r total (0.4 vs 0.9), pain (0.5 vs 1.2), activity (0.2 vs0.7), and self-image (0.6 vs 1.3) than the yes group, respectively (p<0.05). MCID was reached in 28-56% of no group vs 62- 81% of yes group. Patient willingness to receive surgery varied by surgical institution (70% to 89%; p<0.05). Surgeons accurately identified yes group (91%) but poorly identified the no group (22%; p<0.05).
Conclusion(s): ASD patient willingness to undergo same surgery is important for counseling. Unwillingness for same surgery was associated with PROMs, MCID and complications requiring surgery. Surgeons were poorly able to identify patients unwilling to undergo the same surgery. More research is needed to understand patient experiences recovering from ASD surgeries. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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