Bydon, Mohamad

OBJECTIVE Chordomas are rare tumors from notochordal remnants and account for 1%–4% of all primary bone malignancies, often arising from the clivus and sacrum. Despite margin-negative resection and postoperative radiotherapy, chordomas often recur. Further, immunohistochemical (IHC) markers have not been assessed as predictive of chordoma recurrence. The authors aimed to identify the IHC markers that are predictive of postoperative long-term (≥ 1 year) chordoma recurrence by using trained multiple tree-based machine learning (ML) algorithms. METHODS The authors reviewed the records of patients who had undergone treatment for clival and spinal chordomas between January 2017 and June 2021 across the Mayo Clinic enterprise (Minnesota, Florida, and Arizona). Demographics, type of treatment, histopathology, and other relevant clinical factors were abstracted from each patient record. Decision tree and random forest classifiers were trained and tested to predict long-term recurrence based on unseen data using an 80/20 split. RESULTS One hundred fifty-one patients diagnosed and treated for chordomas were identified: 58 chordomas of the clivus, 48 chordomas of the mobile spine, and 45 chordomas sacrococcygeal in origin. Patients diagnosed with cervical chordomas were the oldest among all groups (58 ± 14 years, p = 0.009). Most patients were male (n = 91, 60.3%) and White (n = 139, 92.1%). Most patients underwent resection with or without radiation therapy (n = 129, 85.4%). Subtotal resection followed by radiation therapy (n = 51, 33.8%) was the most common treatment modality, followed by gross-total resection then radiation therapy (n = 43, 28.5%). Multivariate analysis showed that S100 and pan-cytokeratin are more likely to predict the increase in the risk of postoperative recurrence (OR 3.67, 95% CI 1.09–12.42, p= 0.03; and OR 3.74, 95% CI 0.05–2.21, p = 0.02, respectively). In the decision tree analysis, a clinical follow-up > 1897 days was found in 37% of encounters and a 90% chance of being classified for recurrence (accuracy = 77%). Random forest analysis (n = 500 trees) showed that patient age, type of surgical treatment, location of tumor, S100, pan-cytokeratin, and EMA are the factors predicting long-term recurrence. CONCLUSIONS The IHC and clinicopathological variables combined with tree-based ML tools successfully demonstrated a high capacity to identify recurrence patterns with an accuracy of 77%. S100, pan-cytokeratin, and EMA were the IHC drivers of recurrence. This shows the power of ML algorithms in analyzing and predicting outcomes of rare conditions of a small sample size.

OBJECTIVE High-grade gliomas (HGGs) are among the rarest yet most aggressive tumor types in neurosurgical practice. In the current literature, few studies have assessed the drivers of early outcomes following resection of these tumors and investigated their association with quality of care. The authors aimed to identify the clinical predictors for 30-day readmission and reoperation following HGG surgery using the American College of Surgeons (ACS) National Surgical Quality Improvement Project (NSQIP) database and sought to create web-based applications predicting each outcome. METHODS Using the ACS NSQIP database, the authors conducted a retrospective, multicenter cohort analysis of patients who underwent resection of supratentorial HGGs between January 1, 2016, and December 31, 2020. Demographics and comorbidities were extracted. The primary outcomes were 30-day unplanned readmission and reoperation. A stratified 80:20 split of the available data was carried out. Supervised machine learning algorithms were trained to predict 30-day outcomes. RESULTS A total of 9418 patients were included in our cohort. The observed rate of unplanned readmission within 30 days of surgery was 13.0% (n = 1221). In terms of predictors, weight, chronic steroid use, preoperative blood urea nitrogen level, and white blood cell count were associated with a higher risk of readmission. The observed rate of unplanned reoperation within 30 days of surgery was 5.2% (n = 489). In terms of predictors, increased weight, longer operative time, and more days between hospital admission and operation were associated with an increased risk of early reoperation. The random forest algorithm showed the highest predictive performance for early readmission (area under the curve [AUC] = 0.967), while the XGBoost algorithm showed the highest predictive performance for early reoperation (AUC = 0.985). Web-based tools for both outcomes were deployed ( https://glioma-readmission.herokuapp.com/ and https://glioma-reoperation.herokuapp.com/ ). CONCLUSIONS In this study, the authors provide the first nationwide analysis for short-term outcomes in patients undergoing resection of supratentorial HGGs. Multiple patient, hospital, and admission factors were associated with readmission and reoperation, confirmed by machine learning predicting patients’ prognosis, leading to better planning preoperatively and subsequently improved personalized patient care.

Study Design. External validation using prospectively collected data. Objectives. To determine the model performance of “Dialogue Support” (DS) in predicting outcomes after lumbar spine surgery. Summary of Background Data. To help clinicians discuss risk versus benefit with patients considering lumbar fusion surgery, DS has been made available online. As DS was created using a Swedish sample, there is a need to study how well DS performs in alternative populations. Patients and Methods. Preoperative data from patients enrolled in the Quality Outcomes Database were entered into DS. The probability for each patient to report satisfaction, achieve success (leg pain improvement ≥3), or have no leg pain 12 months after surgery was extracted and compared with their actual 12-month postoperative data. The ability of DS to identify patients in the Quality Outcomes Database who report satisfaction, achieve success, or have no leg pain 12 months after surgery was determined using Receiver operating characteristic curve analysis, goodness-of-fit tests, and calibration plots. Results. There was a significant improvement in all outcomes in 23,928 cases included in the analysis from baseline to 12 months postoperative. Most (84%) reported satisfaction, 67% achieved success, and 44% were pain-free 12 months postoperative. Receiver operating characteristic analysis showed that DS had a low ability to predict satisfaction [area under the curve (AUC) = 0.606], success (AUC = 0.546), and being pain-free (AUC = 0.578) at 12 months postoperative; poor fit for satisfaction (<0.001) and being pain-free (P = 0.004), but acceptable fit for success (P = 0.052). Calibration plots showed underestimation for satisfaction and success, but acceptable estimates for being pain-free. Conclusion. DS is not directly transferable to predict satisfaction and success after lumbar surgery in a US population. This may be due to differences in patient characteristics, weights of the variables included, or the exclusion of unknown variables associated with outcomes. Future studies to better understand and improve the transferability of these models are needed.

OBJECTIVE Clear diagnostic delineation is necessary for the development of a strong evidence base in lumbar spinal surgery. Experience with existing national databases suggests that International Classification of Diseases, Tenth Edition (ICD-10) coding is insufficient to support that need. The purpose of this study was to assess agreement between surgeon-specified diagnostic indication and hospital-reported ICD-10 codes for lumbar spine surgery. METHODS Data collection for the American Spine Registry (ASR) includes an option to denote the surgeon’s specific diagnostic indication for each procedure. For cases treated between January 2020 and March 2022, surgeon-delineated diagnosis was compared with the ICD-10 diagnosis generated by standard ASR electronic medical record data extraction. For decompression-only cases, the primary analysis focused on the etiology of neural compression as determined by the surgeon versus that determined on the basis of the related ICD-10 codes extracted from the ASR database. For lumbar fusion cases, the primary analysis compared structural pathology, which may have required fusion, as determined by the surgeon versus that determined on the basis of the extracted ICD-10 codes. This allowed for identification of agreement between surgeon delineation and extracted ICD-10 codes. RESULTS In 5926 decompression-only cases, agreement between the surgeon and ASR ICD-10 codes was 89% for spinal stenosis and 78% for lumbar disc herniation and/or radiculopathy. Both the surgeon and database indicated no structural pathology (i.e., none) suggesting the need for fusion in 88% of cases. In 5663 lumbar fusion cases, agreement was 76% for spondylolisthesis but poor for other diagnostic indications. CONCLUSIONS Agreement between surgeon-specified diagnostic indication and hospital-reported ICD-10 codes was best for patients who underwent decompression only. In the fusion cases, agreement with ICD-10 codes was best in the spondylolisthesis group (76%). In cases other than spondylolisthesis, agreement was poor due to multiple diagnoses or lack of an ICD-10 code that reflected the pathology. This study suggested that standard ICD-10 codes may be inadequate to clearly define the indications for decompression or fusion in patients with lumbar degenerative disease.

OBJECTIVE The Quality Outcomes Database (QOD) was established in 2012 by the NeuroPoint Alliance, a nonprofit organization supported by the American Association of Neurological Surgeons. Currently, the QOD has launched six different modules to cover a broad spectrum of neurosurgical practice—namely lumbar spine surgery, cervical spine surgery, brain tumor, stereotactic radiosurgery (SRS), functional neurosurgery for Parkinson’s disease, and cerebrovascular surgery. This investigation aims to summarize research efforts and evidence yielded through QOD research endeavors. METHODS The authors identified all publications from January 1, 2012, to February 18, 2023, that were produced by using data collected prospectively in a QOD module without a prespecified research purpose in the context of quality surveillance and improvement. Citations were compiled and presented along with comprehensive documentation of the main study objective and take-home message. RESULTS A total of 94 studies have been produced through QOD efforts during the past decade. QOD-derived literature has been predominantly dedicated to spinal surgical outcomes, with 59 and 22 studies focusing on lumbar and cervical spine surgery, respectively, and 6 studies focusing on both. More specifically, the QOD Study Group—a research collaborative between 16 high-enrolling sites—has yielded 24 studies on lumbar grade 1 spondylolisthesis and 13 studies on cervical spondylotic myelopathy, using two focused data sets with high data accuracy and long-term follow-up. The more recent neuro-oncological QOD efforts, i.e., the Tumor QOD and the SRS Quality Registry, have contributed 5 studies, providing insights into the real-world neuro-oncological practice and the role of patient-reported outcomes. CONCLUSIONS Prospective quality registries are an important resource for observational research, yielding clinical evidence to guide decision-making across neurosurgical subspecialties. Future directions of the QOD efforts include the development of research efforts within the neuro-oncological registries and the American Spine Registry—which has now replaced the inactive spinal modules of the QOD—and the focused research on high-grade lumbar spondylolisthesis and cervical radiculopathy.

OBJECTIVE Bone morphogenetic proteins (BMPs) are part of the transforming growth factor–beta superfamily and are involved in bone formation and repair. In spine surgery, recombinant human BMP (rhBMP) is used as an alternative to autografts for spinal fusions. This study aimed to evaluate bibliometric parameters and citations of the literature on BMPs to provide an overview of how the field has evolved. METHODS A comprehensive search of the literature was conducted using Elsevier’s Scopus database to capture all the published and indexed studies relevant to BMPs from 1955 to the present. A discrete set of validated bibliometric parameters was extracted and analyzed. All statistical analyses were performed using R 4.1.1. RESULTS The 100 most cited articles were published between 1994 and 2018 by 472 unique authors in 40 sources (e.g., journals and books). On average, there were 279 citations per publication and 17.69 citations per publication per year. The United States had the publications with the most citations (n = 23,761), followed by Hong Kong (n = 580) and the United Kingdom (n = 490). The three institutions in the United States with the greatest number of publications in the field were Emory University (n = 14), Hughston Clinic (n = 9), Hospital for Special Surgery (n = 6), and University of California (n = 6). CONCLUSIONS The authors evaluated and characterized the 100 most cited articles about BMP. Most of the publications were clinical in nature and focused on BMP’s application in spine surgery. While early scientific efforts focused on basic science research to advance the understanding of BMP’s mechanism of action in promoting bone formation, the majority of the more recent publications are clinically focused. It will be beneficial to conduct more controlled clinical trials to compare the outcomes of BMP use with other methods.

OBJECTIVE The American Spine Registry (ASR) is a collaborative effort between the American Academy of Orthopaedic Surgeons and the American Association of Neurological Surgeons. The goal of this study was to evaluate how representative the ASR is of the national practice with spinal procedures, as recorded in the National Inpatient Sample (NIS). METHODS The authors queried the NIS and the ASR for cervical and lumbar arthrodesis cases performed during 2017–2019. International Classification of Diseases, 10th Revision and Current Procedural Terminology codes were used to identify patients undergoing cervical and lumbar procedures. The two groups were compared for the overall proportion of cervical and lumbar procedures, age distribution, sex, surgical approach features, race, and hospital volume. Outcomes available in the ASR, such as patient-reported outcomes and reoperations, were not analyzed due to nonavailability in the NIS. The representativeness of the ASR compared to the NIS was assessed via Cohen’s d effect sizes, and absolute standardized mean differences (SMDs) of < 0.2 were considered trivial, whereas > 0.5 were considered moderately large. RESULTS A total of 24,800 arthrodesis procedures were identified in the ASR for the period between January 1, 2017, and December 31, 2019. During the same time period, 1,305,360 cases were recorded in the NIS. Cervical fusions comprised 35.9% of the ASR cohort (8911 cases) and 36.0% of the NIS cohort (469,287 cases). The two databases presented trivial differences in terms of patient age and sex for all years of interest across both cervical and lumbar arthrodeses (SMD < 0.2). Trivial differences were also noted in the distribution of open versus percutaneous procedures of the cervical and lumbar spine (SMD < 0.2). Among lumbar cases, anterior approaches were more common in the ASR than in the NIS (32.1% vs 22.3%, SMD = 0.22), but the discrepancy among cervical cases in the two databases was trivial (SMD = 0.03). Small differences were illustrated in terms of race, with SMDs < 0.5, and a more significant discrepancy was identified in the geographic distribution of participating sites (SMDs of 0.7 and 0.74 for cervical and lumbar cases, respectively). For both of these measures, SMDs in 2019 were smaller than those in 2018 and 2017. CONCLUSIONS The ASR and NIS databases presented a very high similarity in proportions of cervical and lumbar spine surgeries, as well as similar distributions of age and sex, and distribution of open versus endoscopic approach. Slight discrepancies in anterior versus posterior approach among lumbar cases and patient race, and more significant discrepancies in geographic representation were also identified, yet decreasing trends in differences suggested the improving representativeness of the ASR over the course of time and its progressive growth. These conclusions are important to underline the external validity of quality investigations and research conclusions to be drawn from analyses in which the ASR is used.

OBJECTIVE Pseudoaneurysms (PSAs) are complex vascular lesions. Flow diversion has been proposed as an alternative treatment to parent artery occlusion that preserves laminar flow. The authors of the present study investigated the safety and short-term (< 1 year) and long-term (≥ 1 year) aneurysm occlusion rates following the treatment of intracranial and extracranial PSAs using the Pipeline embolization device (PED). METHODS An electronic database search for full-text English-language articles in Ovid MEDLINE and Epub Ahead of Print, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus was conducted following the PRISMA guidelines. Studies of any design including at least 4 patients with intracranial or extracranial PSAs treated using a PED were included in this analysis. The primary outcome of interest was the rate of peri- and postprocedural complications. Secondarily, the authors analyzed the incidence of complete aneurysm occlusion. RESULTS A total of 90 patients with 96 PSAs across 9 studies were included. The mean age was 38.2 (SD 15.14) years, and 37.8% of the patients were women. The mean PSA size was 4.9 mm. Most PSAs were unruptured, and the most common etiology was trauma (n = 32, 35.5%), followed by spontaneous formation (n = 21, 23.3%) and iatrogenic injury (n = 19, 21.1%). Among the 51 (53.1%) intracranial and 45 (46.9%) extracranial PSAs were 19 (19.8%) dissecting PSAs. Sixty-six (77.6%) PSAs were in the internal carotid artery and 10 (11.8%) in the vertebral artery. Thirty-three (34.4%) PSAs were treated with ≥ 2 devices, and 8 (8.3%) underwent adjunctive coiling. The mean clinical and angiographic follow-up durations were 10.7 and 12.9 months, respectively. The short-term (< 1 year) and long-term (≥ 1 year) complete occlusion rates were 79% (95% CI 66%–88%, p = 0.82) and 84% (95% CI 70%–92%, p = 0.95), respectively. Complication rates were 8% for iatrogenic dissection (95% CI 3%–16%, p = 0.94), 10% for silent thromboembolism (95% CI 5%–21%, p = 0.77), and 12% for symptomatic thromboembolism (95% CI 6%–23%, p = 0.48). No treatment-related hemorrhage was observed. The overall mortality rate at the last follow-up was 14%. CONCLUSIONS The complete occlusion rate for PSAs treated with the PED was high and increased over time. Although postprocedural complications and mortality were not insignificant, flow diversion represents a reasonably safe option for managing these complex lesions.