Faculty Bibliography

Study DesignLiterature review.ObjectiveTo provide a concise review of outcomes of decompression and fusion (D + F) vs decompression (D) alone for degenerative lumbar spondylolisthesis (DLS).Methods6 articles were selected, including 3 randomized clinical trials (RCT), 2 meta-analyses, and 1 radiographic cohort study. Summarized factors affecting the outcomes of D + F vs D alone for DLS and provide expert level clinical recommendations.ResultsGhogawala included DLS patients showing improved SF-36 scores (P = 0.046) and lower re-operation rates (P = 0.05) in D + F patients compared to D alone. Forsth, included patients with stenosis both with and without DLS, and showed no difference in any reported outcome measure or reoperation rate. Austevoll included DLS patients that found that D alone was non-inferior to D + F in the primary outcome measure of ODI reduction at 2-year after surgery. Gadjradi included studies showing higher morbidity in the D + F group, as compared to D alone. Shukla included studies which found there was no difference in the raw patient outcome scores at final follow-up. Blumenthal included DLS patients who received D and reported disc height of >6.5 mm, facet angle >50°, and dynamic motion >1.25 mm were associated with high re-operation rates (45%, 39%, and 54% respectively).ConclusionsThe RCT's and meta-analyses report contradictory conclusions and no blanket statement regarding the efficacy of D + F vs D alone can be made for all patients with DLS. Surgeons should closely review pre-operative imaging for signs of instability in order to better identify appropriate patients for each indication.

Study DesignSystematic review.ObjectiveThe current literature suggests that decompression-only procedures may be an adequate treatment option for low-grade degenerative spondylolisthesis. It is necessary to understand the causes of the failure to adequately select patients to achieve acceptable results. Our aim is to identify factors associated with failure of decompression-only procedures for degenerative lumbar spondylolisthesis.MethodsAn independent systematic review of scientific databases (PubMed, Scopus, clinicaltrials. gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies analysing the risk factors for failure following decompression-only procedure for degenerative lumbar spondylolisthesis were included. The pooled analysis was performed using the Stata software.ResultsSix studies were included with the baseline characteristics of the successful group and the failed group. Individual study analysis has found factors like motion at index level, and multi-level decompression to be responsible for failure. However, upon pooled analysis patient-related factors (age, sex, BMI), disease-related factors (Pfirrmann grade, slip distance, disc height, facet angulation, translation, movement at index level, sacral slope), and outcome parameters (VAS, ODI and JOA score) between the two groups did not demonstrate any significant difference.ConclusionHigh-quality evidence analysing the risk factors for failure of decompression-only procedure for degenerative spondylolisthesis is limited. Although factors such as motion at index level, and multi-level decompression were found to be potential risk factors in individual studies, pooled analysis did not find any of them to significantly predict failure of decompression-only procedures for degenerative spondylolisthesis.

STUDY DESIGN/METHODS:Retrospective database study. OBJECTIVE:Compare the revision rates of 2-level ACDF, CDR, and hybrid ACDF/CDR. SUMMARY OF BACKGROUND DATA/BACKGROUND:While single-level CDR has been extensively studied, multilevel CDR and hybrid ACDF/CDR constructs have been less well studied. METHODS:This study utilized a large commercial insurance database of patients 65 years old or younger. Patients undergoing 2-level ACDF, 2-level CDR, and hybrid 2-level ACDF/CDR were identified. Patients age 18 years or older with malignant, infectious, or neoplastic etiologies were excluded, as were those undergoing revision surgery or any concomitant posterior cervical surgery. Study follow-up was terminated at 5 years postoperatively. The primary outcome was revision surgery, including anterior and posterior decompression, fusion, and arthroplasty. RESULTS:A total of 99,282 patients were included. The mean age was 51.3 years old (SD 8.1). The mean maximum follow-up was 2.1 years (SD 1.7). In all 3.2% (n=3197) underwent 2-level CDR, 0.5% (n=448) underwent hybrid 2-level ACDF/CDR, and 96.3% (n=95,637) underwent 2-level ACDF. At 5 years postoperatively, in Kaplan-Meier analysis, revision occurred in 10.0% of the CDR group, 12.4% of the hybrid group, and 10.0% of the ACDF group. In multivariable regression analysis, no significant differences in revision occurrence were observed between the CDR, hybrid, and ACDF groups (P<0.15 for all comparisons). In multivariable regression analysis stratified by plate versus stand-alone cage, patients with plated hybrid constructs had higher revision rates than those with both plated ACDF constructs (HR: 1.5, P=0.0387) and 2-level CDR (HR: 1.5, P=0.0477). CONCLUSIONS:In this retrospective database study of patients 65 years old or younger undergoing 2-level anterior cervical surgery, there were no significant differences at 5-year follow-up in revision rates for patients undergoing 2-level CDR, 2-level ACDF, and hybrid ACDF/CDR surgeries. In subanalysis, patients specifically with a plated hybrid ACDF/CDR had a higher occurrence of revision versus those undergoing plated 2-level ACDF or 2-level CDR. Future multicenter, prospective research is necessary to further assess these findings.

BACKGROUND/UNASSIGNED:The concept of spinal instability has been the subject of research since the 1940s and is commonly used in clinical practice to decide on patient treatment. This is despite the lack of an adequately validated diagnostic test for instability. Our goal is to describe automated tests to detect segmental translational and vertical instabilities that can be obtained from lumbar flexion-extension radiographs. We also assess the prevalence of these instabilities in different patient populations. METHODS/UNASSIGNED:Using fully automated methods: (I) flexion-extension studies of asymptomatic volunteers were analyzed to understand the performance of instability metrics in that population; (II) 7,621 lumbar spine flexion-extension from multiple clinical studies were analyzed to document the prevalence of sagittal plane translational and vertical instabilities, corrected for the amount of intervertebral rotation, across different patient populations. RESULTS/UNASSIGNED:Translational or vertical motion abnormalities were rare (<4% of levels) in the asymptomatic population, and the magnitude of translational motion was associated with radiographic disc degeneration (P<0.0001). Sagittal plane translational instabilities were uncommon (<4% of treatment levels) in lumbar disc arthroplasty and biologic disc treatment patients. They were more common (11% to 16% of treatment levels) in lumbar stenosis, lumbar fusion, and dynamic stabilization patients. A higher prevalence of vertical instabilities (27% to 48% of treatment levels) was seen in patients treated for lumbar stenosis and those selected for fusion or dynamic stabilization than those enrolled in disc arthroplasty studies or studies investigating biologics for disc disease treatment (6% to 11% of treatment levels). CONCLUSIONS/UNASSIGNED:New and fully automated approaches to detecting abnormal sagittal plane intervertebral motion may lead to enhanced and standardized diagnosis of lumbar spine instability. Further clinical research is imperative to verify prevalences and validate the efficacy of these metrics in diagnosis and treatment algorithms. If supported by additional research, these metrics may help determine, for example, which lumbar spinal stenosis patients require fusion in addition to decompression surgery.

PURPOSE/OBJECTIVE:To compare 0.55 T and 3 T MRI for imaging patients with titanium total hip arthroplasty (THA). Patients with orthopedic metallic implants often require diagnostic imaging to evaluate adjacent tissues. MRI performance measures, including artifact levels and SNR, vary with field strength. METHODS:Six patients with titanium THA were scanned with similar protocols at 0.55 T and 3 T, including proton density (PD) weighted turbo spin echo (TSE), PD TSE with view-angle tilting (TSE + VAT), PD slice encoding for metal artifact correction (SEMAC), and short tau inversion recovery with SEMAC (STIR-SEMAC). Images from both field strengths were scored by two readers and qualitatively and quantitatively compared. RESULTS:Diagnostic confidence was significantly higher at 0.55 T compared to 3 T. Perceived metal artifact was substantially reduced at 0.55 T compared to 3 T. At 0.55 T, diagnostic imaging was achieved both without and with multi spectral imaging (MSI) for PD weighted images. CONCLUSION/CONCLUSIONS:Compared to 3 T, 0.55 T MRI offers substantially reduced metal artifacts and higher diagnostic confidence when imaging titanium THA. Advanced multi-spectral techniques may not be required when the metallic components are entirely titanium.

BACKGROUND CONTEXT/BACKGROUND:Lumbar disc herniation (LDH) is a leading cause of low back pain (LBP) and leg pain and may require surgical treatment in case of persistent pain and/or neurological deficits. Conventional discectomy involves removing the herniated fragment and additional material from the disc space, potentially accelerating disc degeneration and contributing to chronic LBP. Conversely, by resecting the herniated fragment only, sequestrectomy may reduce postoperative LBP while increasing the risk of LDH recurrence. PURPOSE/OBJECTIVE:To compare discectomy versus sequestrectomy in terms of risk of reherniation, reoperation rate, complications, pain, satisfaction, and perioperative outcomes (operative time, blood loss, length of stay [LOS]). STUDY DESIGN/METHODS:Systematic review and meta-analysis. METHODS:A systematic search of PubMed/MEDLINE and Scopus databases was performed through May 1, 2024 for both randomized and nonrandomized studies. The search was conducted according to PRISMA guidelines. The RoB-2 and MINORS tools were utilized to assess the risk of bias in included studies. The quality of the evidence was evaluated according to the GRADE approach. Relevant outcomes were pooled for meta-analysis. RESULTS:A total of 16 articles (1 randomized controlled trial with 2 follow-up studies, 6 prospective studies, and 7 retrospective studies) published between 1991 and 2020 involving 2009 patients were included for analysis. No significant differences were noted between discectomy versus sequestrectomy in terms of risk of reherniation (OR: 0.85, 95% CI: 0.57 to 1.26, p=.42), reoperation rate (OR: 0.95, 95% CI: 0.64 to 1.40, p=.78), and complications (OR: 1.03, 95% CI: 0.50 to 2.11, p=.94). Although LBP (MD: -0.06, 95% CI: -0.39 to 0.28, p=.74) and leg pain intensity (MD: 0.11, 95% CI: -0.21 to 0.42, p=.50) were similar postoperatively, significantly better outcomes were reported by patients treated with sequestrectomy at 1 year (leg pain: MD: 0.37, 95% CI: 0.19 to 0.54, p<.0001) and 2 years (LBP: MD: 0.19, 95% CI: 0.03 to 0.34, p=.02; leg pain: MD: 0.20, 95% CI: 0.09 to 0.31, p=.0005). Sequestrectomy also resulted in a higher patient satisfaction (OR: 0.60, 95% CI: 0.40 to 0.90, p=.01) and shorter operative time (MD: 8.71, 95% CI: 1.66 to 15.75, p=.02), while blood loss (MD: 0.18, 95% CI: -2.31 to 2.67, p=.89) and LOS (MD: 0.02 days, 95% CI: -0.07 to 0.12, p=.60) did not significantly differ compared to discectomy. CONCLUSIONS:Based on the current evidence, discectomy and sequestrectomy do not significantly differ in terms of risk of reherniation, reoperation rate, and postoperative complications. Patients treated with sequestrectomy may benefit from a marginally higher pain improvement, better satisfaction outcomes, and a shorter operative time, although the clinical relevance of these differences needs to be validated in larger, prospective, randomized studies.

STUDY DESIGN/METHODS:Multicenter, prospective observational cohort study. OBJECTIVES/OBJECTIVE:109 patients with lumbar spine stenosis (LSS) undergoing minimally invasive decompression in 6 different centers (Germany, Italy, USA). METHODS:The demographic, surgical and clinical data was collected. Patients were examined preoperatively, immediately postoperatively, at 6 and 12 months after surgery with regard to pain (back and legs) and functional outcomes (ODI, SF-36, EQ5D). RESULTS:= 0.011). SF36 physical scores also showed initial improvement but plateaued at follow-ups. Notably, high BMI and prior spine surgery were associated with worse outcomes. CONCLUSION/CONCLUSIONS:Although minimally invasive decompression without fusion initially led to a significant improvement in patients with LSS, the results deteriorated significantly over the course of the observation period. Future studies should focus on strategies to ensure sustained improvement in symptoms in patients with lumbar stenosis undergoing decompression procedure.

Background Epidural steroid injections (ESIs) are a common conservative treatment for mitigating radicular pain and are often used to relieve pain, increase function, and improve mobility. However, their efficacy and duration of pain relief are relatively unclear because of the variability in clinical indications, injection techniques, injection mixtures, the number of allowable injections, and the lack of standard and objective outcome measures in the literature. Objectives This study aimed to characterize the effectiveness of ESIs in improving pain, measured with numerical rating scale (NRS) scores, and their relationship with subsequent lumbar spine surgery within a one-year period. Methods Patients who received a lumbar ESI from January 2018 to March 2022 in the Keck Medical Center of the University of Southern California were identified. Only patients with a one-year follow-up and no traumatic injuries were included. Exclusion criteria included a prior lumbar ESI within five years prior to January 2018. Demographics, comorbidities, injection information, and NRS scores were extracted. NRS score comparisons were analyzed with the Wilcoxon signed-rank test. Significance was defined at p ≤ 0.05. Results A total of 143 ESI patients were identified. The patient population consisted of 62 (43.36%) male, 81 (56.64%) female, and a median age of 63 years (IQR: 51,73). Patients who were one- and five-months post-ESI had the greatest median change in NRS of -3 (IQR: -7,0) (p < 0.05 for all). At one year post-ESI, there was a median decrease in NRS scores by 2 (IQR: 0,5). Of the cohort, only 28 (27.20%) patients went on to have lumbar spine surgery within a year. Conclusion The data suggests ESIs may be effective at relieving pain for at least one year. The data provides some evidence that ESIs are most reliable at relieving pain up to the five-month mark, after which their efficacy decreases.

STUDY DESIGN/METHODS:Cross-sectional survey. OBJECTIVE:Surgical treatment of degenerative lumbar spondylolisthesis is remarkably varied due to heterogeneity of clinical-radiological presentations. This study aimed to assess which spinopelvic radiological parameters were considered for decision-making. METHODS:Survey distributed to International AO Spine members to analyze surgeons' considerations for treatment. Data collected includes demographics, training background, years of experience, and treatment decisions based on various radiographical findings, including segmental and global spinopelvic parameters. RESULTS:= 0.043), respectively. Additionally, the surgeons' age was associated with using angular motion on flexion-extension radiographs, and volume of treated cases yearly with consideration for disc height. CONCLUSIONS:Treatment of degenerative lumbar spondylolisthesis was influenced by slippage on dynamic radiographs, disc height, global alignment, and PI-LL mismatch. Surgeons' age and Region, fellowship-trained, and volume of treated cases were significantly associated to apply these radiological parameters.

BACKGROUND CONTEXT/BACKGROUND:Failure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis. PURPOSE/OBJECTIVE:Develop and test a biomechanically based approach to the diagnosis of pseudoarthrosis. STUDY DESIGN/METHODS:Literature review, development of theory, re-analysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion. METHODS:Fully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients. RESULTS:The estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2 degrees, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases. CONCLUSIONS:We propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery. CLINICAL SIGNIFICANCE/CONCLUSIONS:In a symptomatic post-spine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis.