The Use of Cranial Aneurysm Clips for Repair of Incidental Lumbar Durotomy: Operative Technique and Case Series.

BACKGROUND: Incidental durotomy is a common complication of posterior lumbar spine surgery; however, effective and durable methods for primary repair remain elusive. Multiple existing techniques have previously been reported and extensively described, including sutured repair and the use of nonpenetrating titanium clips. The use of cranial aneurysm clips for primary repair of lumbar durotomy serves as a safe and effective alternative to obtain watertight closure of a dural tear. METHODS: We performed a retrospective review of patients at a single institution who underwent primary repair of an incidental lumbar durotomy with the use of an aneurysm clip during open posterior lumbar surgery between 2012 and 2023. Patient demographics, operative details, and postoperative metrics were collected and examined to evaluate the safety and efficacy of the novel technique. RESULTS: A total of 51 patients were included for analysis. Four patients underwent durotomy repair with an aneurysm clip alone, 27 patients were repaired with an aneurysm clip and fibrin glue, and 20 patients underwent repair with an aneurysm clip, fibrin glue, and a collagen dural substitute. Three patients (5.9%) reported headaches: 2 (3.9%) with pseudomeningocele and 1 (2%) with wound leakage. Two patients (3.9%) had treatment failure with a return to the operating room for repair of a cerebrospinal fluid leak. CONCLUSIONS: To the best of our knowledge, we report the largest series of patients undergoing primary repair of incidental durotomy with the use of an aneurysm clip. Use of an aneurysm clip is noted to be a safe, quick, and effective method of primary repair compared with existing repair techniques such as sutured repair or nonpenetrating titanium clips.

Risk assessment of early therapeutic anticoagulation following cranial surgery: an institutional case series.

OBJECTIVE: Postoperative thrombotic complications represent a unique challenge in cranial neurosurgery as primary treatment involves therapeutic anticoagulation. The decision to initiate therapy and its timing is nuanced, as surgeons must balance the risk of catastrophic intracranial hemorrhage (ICH). With limited existing evidence to guide management, current practice patterns are subjective and inconsistent. The authors assessed their experience with early therapeutic anticoagulation (≤ 7 days postoperatively) initiation for thrombotic complications in neurosurgical patients undergoing cranial surgery to better understand the risks of catastrophic ICH. METHODS: Adult patients treated with early therapeutic anticoagulation following cranial surgery were considered. Anticoagulation indications were restricted to thrombotic or thromboembolic complications. Records were retrospectively reviewed for demographics, surgical details, and anticoagulation therapy start. The primary outcome was the incidence of catastrophic ICH, defined as ICH resulting in reoperation or death within 30 days of anticoagulation initiation. As a secondary outcome, post-anticoagulation cranial imaging was reviewed for new or worsening acute blood products. Fisher's exact and Wilcoxon rank-sum tests were used to compare cohorts. Cumulative outcome analyses were performed for primary and secondary outcomes according to anticoagulation start time. RESULTS: Seventy-one patients satisfied the inclusion criteria. Anticoagulation commenced on mean postoperative day (POD) 4.3 (SD 2.2). Catastrophic ICH was observed in 7 patients (9.9%) and was associated with earlier anticoagulation initiation (p = 0.02). Of patients with catastrophic ICH, 6 (85.7%) had intra-axial exploration during their index surgery. Patients with intra-axial exploration were more likely to experience a catastrophic ICH postoperatively compared to those with extra-axial exploration alone (OR 8.5, p = 0.04). Of the 58 patients with postoperative imaging, 15 (25.9%) experienced new or worsening blood products. Catastrophic ICH was 9 times more likely with anticoagulation initiation within 48 hours of surgery (OR 8.9, p = 0.01). The cumulative catastrophic ICH risk decreased with delay in initiation of anticoagulation, from 21.1% on POD 2 to 9.9% on POD 7. Concurrent antiplatelet medication was not associated with either outcome measure. CONCLUSIONS: The incidence of catastrophic ICH was significantly increased when anticoagulation was initiated within 48 hours of cranial surgery. Patients undergoing intra-axial exploration during their index surgery were at higher risk of a catastrophic ICH.

Presence of Cerebrospinal Fluid on Preoperative Imaging and the Associated Cervical Myelopathy Diagnosis and Outcome.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: The objective of this study is to determine whether the presence of cerebrospinal fluid is associated with the severity of degenerative cervical myelopathy or postoperative outcomes. SUMMARY OF BACKGROUND DATA: Degenerative cervical myelopathy (DCM) is a clinical diagnosis characterized as neurologic dysfunction. Preoperative imaging is used to determine the source of cord compression. In clinical practice, cerebrospinal fluid (CSF) around the cord is often used as an indicator to determine whether stenosis is relevant. It is unclear if the presence of CSF around the cord can serve as a metric for clinically relevant cord compression. METHODS: Patients undergoing single-level anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy were identified from our institution's surgical database. Pre- and postoperative patient-reported health outcomes visual analog scale for neck pain (VAS-NP) and modified Japanese Orthopaedic Association (mJOA) were collected. The level of ACDF plus one level above and below were assessed for the presence of cerebrospinal fluid, as well as measuring the area of the spinal canal and spinal cord on preoperative magnetic resonance imaging. RESULTS: Two hundred forty-nine patients were included. Spearman correlation test comparing cord/canal ratios at the level of compression and preoperative mJOA shows a significant negative correlation (Rho = -0.206, P= 0.043). There was no significant correlation with postoperative change in mJOA scores (Rho = -0.002, P= 0.986). CONCLUSION: The presence of CSF around the cord was weakly correlated with the severity of myelopathy; however, it had no correlation with postoperative outcomes. The presence of CSF around the cord should not in isolation be used to rule in or rule out operative levels in cervical myelopathy.

A retrospective analysis of perioperative complications of lateral approach lumbar interbody fusion in patients with prior abdominal surgery or a history of colonic inflammatory disease.

BACKGROUND CONTEXT: Lateral approaches for lumbar interbody fusion (LIF) allow for access to the lumbar spine and disk space by passing through a retroperitoneal corridor either pre- or trans-psoas. A contraindication for this approach is the presence of retroperitoneal scarring that may occur from prior surgical intervention in the retroperitoneal space or from inflammatory conditions with fibrotic changes and pose challenges for the mobilization and visualization needed in this approach. However, there is a paucity of evidence on the prevalence of surgical complications following lateral fusion surgery in patients with a history of abdominal surgery. PURPOSE: The primary aim of this study is to describe the association between surgical complications following lateral interbody fusion surgery and prior abdominal surgical. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Patients over the age of 18 who underwent lateral lumbar interbody fusion at a large, tertiary care center between 2011 and 2019 were included in the study. OUTCOME MEASURES: The primary outcome included medical, surgical, and thigh-related complications either in the intraoperative or 90-day postoperative periods. Additional outcome metrics included readmission rates, length of stay, and operative duration. METHODS: The electronic health records of 250 patients were reviewed for demographic information, surgical data, complications, and readmission following surgery. The association of patient and surgical factors to complication rate was analyzed using multivariable logistic regression. Statistical analysis was performed using R statistical software (R, Vienna, Austria). RESULTS: Of 250 lateral interbody fusion patients, 62.8% had a prior abdominal surgery and 13.8% had a history of colonic disease. The most common perioperative complication was transient thigh or groin pain/sensory changes (n=62, 24.8%). A multivariable logistic regression considering prior abdominal surgery, age, BMI, history of colonic disease, multilevel surgery, and the approach relative to psoas found no significant association between surgical complication rates and colonic disease (OR 0.40, 95% CI 0.02-2.22) or a history of prior abdominal surgeries (OR 0.56, 95% CI 0.20-1.55). Further, the invasiveness of prior abdominal surgeries showed no association with overall spine complication rate, lateral-specific complications, or readmission rates (p>.05). CONCLUSION: Though retroperitoneal scarring is an important consideration for lateral approaches to the lumbar spine, this study found no association between lateral lumbar approach complication rates and prior abdominal surgery. Further study is needed to determine the impact of inflammatory colonic disease on lateral approach spine surgery.

Exploring tribology and material contact science in spine surgery: implications for implant design.

Tribology, an interdisciplinary field concerned with the science of interactions between surfaces in contact and their relative motion, plays a well-established role in the design of orthopedic implants, such as knee and hip replacements. However, its applications in spine surgery have received comparatively less attention in the literature. Understanding tribology is pivotal in elucidating the intricate interactions between metal, polymer, and ceramic components, as well as their interplay with the native human bone. Numerous studies have demonstrated that optimizing tribological factors is key to enhancing the longevity of joints and implants while simultaneously reducing complications and the need for revision surgeries in both arthroplasty and spinal fusion procedures. With an ever-growing and diverse array of spinal implant devices hitting the market for static and dynamic stabilization of the spine, it is important to consider how each of these devices optimizes these parameters and what factors may be inadequately addressed by currently available technology and methods. In this comprehensive review, the authors' objectives were twofold: 1) delineate the unique challenges encountered in spine surgery that could be addressed through optimization of tribological parameters; and 2) summarize current innovations and products within spine surgery that look to optimize tribological parameters and highlight new avenues for implant design and research.

Predicting hypertension control using machine learning.

Hypertension is a widely prevalent disease and uncontrolled hypertension predisposes affected individuals to severe adverse effects. Though the importance of controlling hypertension is clear, the multitude of therapeutic regimens and patient factors that affect the success of blood pressure control makes it difficult to predict the likelihood to predict whether a patient's blood pressure will be controlled. This project endeavors to investigate whether machine learning can accurately predict the control of a patient's hypertension within 12 months of a clinical encounter. To build the machine learning model, a retrospective review of the electronic medical records of 350,008 patients 18 years of age and older between January 1, 2015 and June 1, 2022 was performed to form model training and testing cohorts. The data included in the model included medication combinations, patient laboratory values, vital sign measurements, comorbidities, healthcare encounters, and demographic information. The mean age of the patient population was 65.6 years with 161,283 (46.1%) men and 275,001 (78.6%) white. A sliding time window of data was used to both prohibit data leakage from training sets to test sets and to maximize model performance. This sliding window resulted in using the study data to create 287 predictive models each using 2 years of training data and one week of testing data for a total study duration of five and a half years. Model performance was combined across all models. The primary outcome, prediction of blood pressure control within 12 months demonstrated an area under the curve of 0.76 (95% confidence interval; 0.75-0.76), sensitivity of 61.52% (61.0-62.03%), specificity of 75.69% (75.25-76.13%), positive predictive value of 67.75% (67.51-67.99%), and negative predictive value of 70.49% (70.32-70.66%). An AUC of 0.756 is considered to be moderately good for machine learning models. While the accuracy of this model is promising, it is impossible to state with certainty the clinical relevancy of any clinical support ML model without deploying it in a clinical setting and studying its impact on health outcomes. By also incorporating uncertainty analysis for every prediction, the authors believe that this approach offers the best-known solution to predicting hypertension control and that machine learning may be able to improve the accuracy of hypertension control predictions using patient information already available in the electronic health record. This method can serve as a foundation with further research to strengthen the model accuracy and to help determine clinical relevance.

Comparison of sleep improvement in patients undergoing lumbar spine decompression.

OBJECTIVE: Degenerative spine conditions affect many people each year. These conditions have been shown to negatively impact pain, function, and patient quality of life (QOL), which often require surgical intervention. It is understood that sleep plays an important role in all of these factors. However, the relationship between sleep disruption and lumbar surgery is not well understood. The objective of this study was to use a large database to understand the relationship between sleep quality and lumbar spine surgery outcomes. METHODS: The surgical database of the authors' institute was used to identify all patients undergoing lumbar spine surgery for degenerative spine disease from January 1, 2012, through December 31, 2021. Patient-Reported Outcomes Measurement Information System (PROMIS) sleep disturbance scores were collected, and only patients with both pre- and postoperative scores were included. Additional measures related to disability, pain, and depression were also obtained. Chart review was performed to collect patient demographics, health risk factors, and information related to sleep disturbances such as sleep medication usage and prior sleep condition diagnosis. RESULTS: The study had 674 patients who met the criteria. At 3, 6, and 12 months postoperatively, there was a significant decrease in sleep disruption scores (i.e., sleep improvement), although these decreases were not greater than the minimal clinically important difference (MCID). When stratified based on preoperative sleep quality, patients with poor preoperative scores (PROMIS sleep disruption > 63.04) showed a significant decrease in sleep disruption by 8.17 at 3 months, 7.99 at 6 months, and 7.21 at 12 months. All of these decreases were greater than the sleep disruption MCID of 6.5. Multivariate analysis showed high preoperative sleep disruption and improvement in PROMIS physical health were most associated with decreased postoperative sleep disruption at all postoperative time points. CONCLUSIONS: In patients with degenerative spine conditions, lumbar spine surgery offers improvement in sleep disruption for all patients. Those with poor preoperative sleep quality are more likely to see clinical improvement in their sleep disruption.

Abnormal L5-S1 Facet Joint Orientation as a Harbinger of Degenerative Spondylolisthesis: A Case Report.

Degenerative spondylolisthesis is a common cause of low back pain and resultant disability in the adult population. The causes of degenerative spondylolisthesis are not entirely understood, though a combination of anatomic and lifestyle factors likely contributes to the development of this pathology. Here, we report a case of a 38-year-old female presenting with low back pain and right lower extremity radiculopathy, found to have degenerative L5-S1 spondylolisthesis, which we postulate developed in part due to the sagittal orientation of her L5-S1 facet joints bilaterally.

Surgical classification using natural language processing of informed consent forms in spine surgery.

OBJECTIVE: In clinical spine surgery research, manually reviewing surgical forms to categorize patients by their surgical characteristics is a crucial yet time-consuming task. Natural language processing (NLP) is a machine learning tool used to adaptively parse and categorize important features from text. These systems function by training on a large, labeled data set in which feature importance is learned prior to encountering a previously unseen data set. The authors aimed to design an NLP classifier for surgical information that can review consent forms and automatically classify patients by the surgical procedure performed. METHODS: Thirteen thousand two hundred sixty-eight patients who underwent 15,227 surgeries from January 1, 2012, to December 31, 2022, at a single institution were initially considered for inclusion. From these surgeries, 12,239 consent forms were classified based on the Current Procedural Terminology (CPT) code, categorizing them into 7 of the most frequently performed spine surgeries at this institution. This labeled data set was split 80%/20% into train and test subsets, respectively. The NLP classifier was then trained and the results demonstrated its performance on the test data set using CPT codes to determine accuracy. RESULTS: This NLP surgical classifier had an overall weighted accuracy rate of 91% for sorting consents into correct surgical categories. Anterior cervical discectomy and fusion had the highest positive predictive value (PPV; 96.8%), whereas lumbar microdiscectomy had the lowest PPV in the testing data (85.0%). Sensitivity was highest for lumbar laminectomy and fusion (96.7%) and lowest for the least common operation, cervical posterior foraminotomy (58.3%). Negative predictive value and specificity were > 95% for all surgical categories. CONCLUSIONS: Utilizing NLP for text classification drastically improves the efficiency of classifying surgical procedures for research purposes. The ability to quickly classify surgical data can be significantly beneficial to institutions without a large database or substantial data review capabilities, as well as for trainees to track surgical experience, or practicing surgeons to evaluate and analyze their surgical volume. Additionally, the capability to quickly and accurately recognize the type of surgery will facilitate the extraction of new insights from the correlations between surgical interventions and patient outcomes. As the database of surgical information grows from this institution and others in spine surgery, the accuracy, usability, and applications of this model will continue to increase.

Stereotactic radiosurgery and resection for treatment of multiple brain metastases: a systematic review and analysis.

OBJECTIVE: Stereotactic radiosurgery (SRS) has recently emerged as a minimally invasive alternative to resection for treating multiple brain metastases. Given the lack of consensus regarding the application of SRS versus resection for multiple brain metastases, the authors aimed to conduct a systematic literature review of all published work on the topic. METHODS: The PubMed, OVID, Cochrane, Web of Science, and Scopus databases were used to identify studies that examined clinical outcomes after resection or SRS was performed in patients with multiple brain metastases. Radiological studies, case series with fewer than 3 patients, pediatric studies, or national database studies were excluded. Data extracted included patient demographics and mean overall survival (OS). Weighted t-tests and ANOVA were performed. RESULTS: A total of 1300 abstracts were screened, 450 articles underwent full-text review, and 129 studies met inclusion criteria, encompassing 20,177 patients (18,852 treated with SRS and 1325 who underwent resection). The OS for the SRS group was 10.2 ± 6 months, and for the resection group it was 6.5 ± 3.8 months. A weighted ANOVA test comparing OS with covariates of age, sex, and publication year revealed that the treatment group (p = 0.045), age (p = 0.034), and publication year (0.0078) were all independently associated with OS (with SRS, younger age, and later publication year being associated with longer survival), whereas sex (p = 0.95) was not. CONCLUSIONS: For patients with multiple brain metastases, SRS and resection are effective treatments to prolong OS, with published data suggesting that SRS may have a trend toward lengthened survival outcomes. The authors encourage additional work examining outcomes of treatments for multiple brain metastases.

Clinical Utility of Routine Postoperative Imaging in Spinal Fusion Surgery: A Systematic Review.

OBJECTIVE: Following spinal fusion surgery, routine imaging is often obtained in all patients regardless of clinical presentation. Such routine imaging may include x-ray, computed tomography, or magnetic resonance imaging studies in both the immediate postoperative period and after discharge. The clinical utility of this practice is questionable. Our goal is to assess the existing literature for evidence of impact on clinical care from routine radiographic surveillance following spinal fusion. METHODS: A systematic search of Embase, Scopus, PubMed, Cochrane, and Ovid databases was performed for studies investigating postoperative imaging following spinal fusion surgery. Studies were analyzed for imaging findings and rates of change in management due to imaging. RESULTS: In total, the review identified 9 studies that separated data by unique patient or by unique clinic visits. The 4 studies reporting per-patient data totaled 475 patients with 328 (69%) receiving routine imaging. Among these, 28 (8.5%) patients had abnormal routine findings with no patients having a change to their clinical course. Of the 5 studies that reported clinic visit data, 3119 patient visits were included with 2365 (76%) clinic visits accompanied by imaging. Across these 5 studies, 146 (6.2%) visits noted abnormal imaging with only 12 (0.5%) subsequent management changes. CONCLUSIONS: Our analysis found that routine imaging after spinal fusion surgery had no direct benefit on clinical management. The utility of baseline imaging for long-term comparison and medicolegal concerns were not studied and remain up to the provider's judgment. Further research is necessary to identify optimal imaging criteria following spinal fusion surgery.

Predictors of Operative Duration and Complications in Single-Level Posterior Interbody Fusions for Degenerative Spondylolisthesis.

BACKGROUND: The goal of this study was to identify predictors of prolonged operative time (OT) in patients receiving posterior/transforaminal lumbar interbody fusion (P/TLIF) and examine the relationship between prolonged OT and perioperative outcomes in this population. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing single-level P/TLIF (Common Procedural Terminology code) between 2012 and 2018. Multivariable linear regression models were constructed to identify factors independently associated with changes in OT and examine the relationship between prolonged OT and perioperative outcomes (overall complications, surgical complications, medical complications, 30-day readmission, 30-day reoperation, and length of stay). All models were adjusted for sociodemographic variables, comorbidities, and procedure-specific variables. RESULTS: Our cohort included 6260 patients. After adjusting for baseline covariates, age between 19 and 39 years increased OT by 15.14 minutes, male sex increased OT by 12.91 minutes, African American race increased OT by 17.82 minutes, other race increased OT by 18.13 minutes, obesity class III increased OT by 27.80 minutes, and the use of navigation increased OT by 10.83 minutes. Our multivariate logistic regression also found that after 2 hours, each additional hour of OT was associated with an increased risk of any complication (3-3.99 hours, odds ratio [OR], 1.68; 4-4.99 hours, OR, 2.33; and >5 hours, OR, 4.65). Incremental increases in OT were also associated with an increased risk of extended length of stay, readmission, and return to the operating room. CONCLUSIONS: The results of this study highlight several factors associated with prolonged OT and underscore its association with poorer perioperative outcomes. These data can be used to risk stratify patients before single-level P/TLIF.

Immediate Postoperative Imaging Following Elective Lumbar Fusion Provides Little Clinical Utility.

STUDY DESIGN: Retrospective review at a single institution of all adult patients who underwent elective lumbar fusion surgery for degenerative spinal disease from 2013 to 2018. Reoperation rates and change in clinical management due to routine imaging findings were the primary outcomes. OBJECTIVE: To investigate what effects immediate routine postoperative imaging has on the clinical management of patients following lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: The clinical utility of routine postoperative imaging following lumbar fusion surgery remains uncertain. Existing studies on the clinical utility of postoperative imaging in lumbar fusion patients have largely focused on imaging obtained post-discharge. We present a retrospective analysis that to our knowledge is the first study reporting on the clinical utility of routine imaging in lumbar fusion patients during the immediate postoperative period. METHODS: The medical records of patients who had undergone elective lumbar instrumented fusion for degenerative disease from 2013 to 2018 by neurosurgeons across one regional healthcare system were retrospectively analyzed. Inpatient records and imaging orders for patients were reviewed. Routine immediate postoperative imaging was defined by any lumbar spine imaging prior to discharge in the absence of specific indications. RESULTS: Analysis identified 115 patients who underwent elective lumbar instrumented fusion for degenerative disease. One-hundred-twelve patients received routine postoperative imaging. Routine imaging was abnormal in four patients (4%). There was one instance (<1%) where routine immediate postoperative imaging led to change in clinical management. Abnormal routine imaging was not associated with either reoperation or development of neurological symptoms postoperatively (P = 0.10), however, new or worsening neurologic deficits did predict reoperation (P < 0.01). CONCLUSION: New neurologic deficit was the only significant predictor of reoperation. Routine imaging, whether normal or abnormal, was not found to be associated with reoperation. The practice of routine imaging prior to discharge following elective lumbar fusion surgery appears to provide little utility to clinical management.Level of Evidence: 3.

Cryo-electron microscopy structure and analysis of the P-Rex1-Gßγ signaling scaffold.

PIP3-dependent Rac exchanger 1 (P-Rex1) is activated downstream of G protein-coupled receptors to promote neutrophil migration and metastasis. The structure of more than half of the enzyme and its regulatory G protein binding site are unknown. Our 3.2 Å cryo-EM structure of the P-Rex1-Gßγ complex reveals that the carboxyl-terminal half of P-Rex1 adopts a complex fold most similar to those of Legionella phosphoinositide phosphatases. Although catalytically inert, the domain coalesces with a DEP domain and two PDZ domains to form an extensive docking site for Gßγ. Hydrogen-deuterium exchange mass spectrometry suggests that Gßγ binding induces allosteric changes in P-Rex1, but functional assays indicate that membrane localization is also required for full activation. Thus, a multidomain assembly is key to the regulation of P-Rex1 by Gßγ and the formation of a membrane-localized scaffold optimized for recruitment of other signaling proteins such as PKA and PTEN.