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.

Mapping PROMIS physical function and pain interference to the modified low back pain disability questionnaire.

PURPOSE: The Modified Low Back Pain Disability Questionnaire (MDQ) is a commonly used tool to assess functioning of patients with low back pain (LBP). Recently, the Patient-Reported Outcomes Measurement Information System (PROMIS) was suggested as an alternative platform to assess LBP patient-reported health. We sought to map between the MDQ and PROMIS Physical Function (PROMIS-PF) and Pain Interference (PROMIS-PI) scales using multiple methods. METHODS: In a retrospective analysis of LBP patients seen at Cleveland Clinic 11/14/18-12/11/19, T-scores from each PROMIS scale were mapped to MDQ total score individually and together. MDQ item and total scores were mapped to each PROMIS scale. Linear regression as well as linear and equipercentile equating were used. Split sample internal validation using root mean squared error (RMSE), mean absolute error (MAE), and correlations were used to assess accuracy of mapping equations. RESULTS: 13585 patients completed the three scales. In the derivation cohort, average age was 59.0 (SD = 15.8); 53.3% female and 82.9% white. Average MDQ total, PROMIS-PF, and PROMIS-PI T-scores were 40.3 (SD = 19.0), 37.2 (SD = 7.6), and 62.9 (SD = 7.2), respectively. For estimating MDQ total scores, methods that used both PROMIS-PF and PROMIS-PI had closest estimated means, lowest RMSE and MAE, and highest correlations. For estimating each of PROMIS-PF and PROMIS-PI T-scores, the best performing method was equipercentile equating using the MDQ items. CONCLUSIONS: We created and internally validated maps between MDQ and PROMIS-PF and PROMIS-PI using linear regression, linear and equipercentile equating. Our equations can be used by researchers wishing to translate scores between these scales.

Effect of Ventral vs Dorsal Spinal Surgery on Patient-Reported Physical Functioning in Patients With Cervical Spondylotic Myelopathy: A Randomized Clinical Trial.

Importance: Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction worldwide. It remains unknown whether a ventral or dorsal surgical approach provides the best results. Objective: To determine whether a ventral surgical approach compared with a dorsal surgical approach for treatment of cervical spondylotic myelopathy improves patient-reported physical functioning at 1 year. Design, Setting, and Participants: Randomized clinical trial of patients aged 45 to 80 years with multilevel cervical spondylotic myelopathy enrolled at 15 large North American hospitals from April 1, 2014, to March 30, 2018; final follow-up was April 15, 2020. Interventions: Patients were randomized to undergo ventral surgery (n = 63) or dorsal surgery (n = 100). Ventral surgery involved anterior cervical disk removal and instrumented fusion. Dorsal surgery involved laminectomy with instrumented fusion or open-door laminoplasty. Type of dorsal surgery (fusion or laminoplasty) was at surgeon's discretion. Main Outcomes and Measures: The primary outcome was 1-year change in the Short Form 36 physical component summary (SF-36 PCS) score (range, 0 [worst] to 100 [best]; minimum clinically important difference = 5). Secondary outcomes included 1-year change in modified Japanese Orthopaedic Association scale score, complications, work status, sagittal vertical axis, health resource utilization, and 1- and 2-year changes in the Neck Disability Index and the EuroQol 5 Dimensions score. Results: Among 163 patients who were randomized (mean age, 62 years; 80 [49%] women), 155 (95%) completed the trial at 1 year (80% at 2 years). All patients had surgery, but 5 patients did not receive their allocated surgery (ventral: n = 1; dorsal: n = 4). One-year SF-36 PCS mean improvement was not significantly different between ventral surgery (5.9 points) and dorsal surgery (6.2 points) (estimated mean difference, 0.3; 95% CI, -2.6 to 3.1; P = .86). Of 7 prespecified secondary outcomes, 6 showed no significant difference. Rates of complications in the ventral and dorsal surgery groups, respectively, were 48% vs 24% (difference, 24%; 95% CI, 8.7%-38.5%; P = .002) and included dysphagia (41% vs 0%), new neurological deficit (2% vs 9%), reoperations (6% vs 4%), and readmissions within 30 days (0% vs 7%). Conclusions and Relevance: Among patients with cervical spondylotic myelopathy undergoing cervical spinal surgery, a ventral surgical approach did not significantly improve patient-reported physical functioning at 1 year compared with outcomes after a dorsal surgical approach. Trial Registration: ClinicalTrials.gov Identifier: NCT02076113.

Comparison of clinical outcomes in decompression and fusion versus decompression only in patients with ossification of the posterior longitudinal ligament: a meta-analysis.

OBJECTIVE Ossification of the posterior longitudinal ligament (OPLL) is a pathological calcification or ossification of the PLL, predominantly occurring in the cervical spine. Although surgery is often necessary for patients with symptomatic neurological deterioration, there remains controversy with regard to the optimal surgical treatment. In this systematic review and meta-analysis, the authors identified differences in complications and outcomes after anterior or posterior decompression and fusion versus after decompression alone for the treatment of cervical myelopathy due to OPLL. METHODS A MEDLINE, SCOPUS, and Web of Science search was performed for studies reporting complications and outcomes after decompression and fusion or after decompression alone for patients with OPLL. A meta-analysis was performed to calculate effect summary mean values, 95% CIs, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 2630 retrieved articles, 32 met the inclusion criteria. There was no statistically significant difference in the incidence of excellent and good outcomes and of fair and poor outcomes between the decompression and fusion and the decompression-only cohorts. However, the decompression and fusion cohort had a statistically significantly higher recovery rate (63.2% vs 53.9%; p < 0.0001), a higher final Japanese Orthopaedic Association score (14.0 vs 13.5; p < 0.0001), and a lower incidence of OPLL progression (< 1% vs 6.3%; p < 0.0001) compared with the decompression-only cohort. There was no statistically significant difference in the incidence of complications between the 2 cohorts. CONCLUSIONS This study represents the only comprehensive review of outcomes and complications after decompression and fusion or after decompression alone for OPLL across a heterogeneous group of surgeons and patients. Based on these results, decompression and fusion is a superior surgical technique compared with posterior decompression alone in patients with OPLL. These results indicate that surgical decompression and fusion lead to a faster recovery, improved postoperative neurological functioning, and a lower incidence of OPLL progression compared with posterior decompression only. Furthermore, decompression and fusion did not lead to a greater incidence of complications compared with posterior decompression only.

Decompression surgery for spinal metastases: a systematic review.

OBJECTIVE The aim of this study was to systematically review the literature on reported outcomes following decompression surgery for spinal metastases. METHODS The authors conducted MEDLINE, Scopus, and Web of Science database searches for studies reporting clinical outcomes and complications associated with decompression surgery for metastatic spinal tumors. Both retrospective and prospective studies were included. After meeting inclusion criteria, articles were categorized based on the following reported outcomes: survival, ambulation, surgical technique, neurological function, primary tumor histology, and miscellaneous outcomes. RESULTS Of the 4148 articles retrieved from databases, 36 met inclusion criteria. Of those included, 8 were prospective studies and 28 were retrospective studies. The year of publication ranged from 1992 to 2015. Study size ranged from 21 to 711 patients. Three studies found that good preoperative Karnofsky Performance Status (KPS ≥ 80%) was a significant predictor of survival. No study reported a significant effect of time-to-surgery following the onset of spinal cord compression symptoms on survival. Three studies reported improvement in neurological function following surgery. The most commonly cited complication was wound infection or dehiscence (22 studies). Eight studies reported that preoperative ambulatory or preoperative motor status was a significant predictor of postoperative ambulatory status. A wide variety of surgical techniques were reported: posterior decompression and stabilization, posterior decompression without stabilization, and posterior decompression with total or subtotal tumor resection. Although a wide range of functional scales were used to assess neurological outcomes, four studies used the American Spinal Injury Association (ASIA) Impairment Scale to assess neurological function. Four studies reported the effects of radiation therapy and local disease control for spinal metastases. Two studies reported that the type of treatment was not significantly associated with the rate of local control. The most commonly reported primary tumor types included lung cancer, prostate cancer, breast cancer, renal cancer, and gastrointestinal cancer. CONCLUSIONS This study reports a systematic review of the literature on decompression surgery for spinal metastases. The results of this study can help educate surgeons on the previously published predictors of outcomes following decompression surgery for metastatic spinal disease. However, the authors also identify significant gaps in the literature and the need for future studies investigating the optimal practice with regard to decompression surgery for spinal metastases.

Lumbar spine surgery positioning complications: a systematic review.

OBJECT There are a variety of surgical positions that provide optimal exposure of the dorsal lumbar spine. These include the prone, kneeling, knee-chest, knee-elbow, and lateral decubitus positions. All are positions that facilitate exposure of the spine. Each position, however, is associated with an array of unique complications that result from excessive pressure applied to the torso or extremities. The authors reviewed clinical studies reporting complications that arose from positioning of the patient during dorsal exposures of the lumbar spine. METHODS MEDLINE, Scopus, and Web of Science database searches were performed to find clinical studies reporting complications associated with positioning during lumbar spine surgery. For articles meeting inclusion criteria, the following information was obtained: publication year, study design, sample size, age, operative time, type of surgery, surgical position, frame or table type, complications associated with positioning, time to first observed complication, long-term outcomes, and evidence-based recommendations for complication avoidance. RESULTS Of 3898 articles retrieved from MEDLINE, Scopus, and Web of Science, 34 met inclusion criteria. Twenty-four studies reported complications associated with use of the prone position, and 7 studies investigated complications after knee-chest positioning. Complications associated with the knee-elbow, lateral decubitus, and supine positions were each reported by a single study. Vision loss was the most commonly reported complication for both prone and knee-chest positioning. Several other complications were reported, including conjunctival swelling, Ischemic orbital compartment syndrome, nerve palsies, thromboembolic complications, pressure sores, lower extremity compartment syndrome, and shoulder dislocation, highlighting the assortment of possible complications following different surgical positions. For prone-position studies, there was a relationship between increased operation time and position complications. Only 3 prone-position studies reported complications following procedures of less than 120 minutes, 7 studies reported complications following mean operative times of 121-240 minutes, and 9 additional studies reported complications following mean operative times greater than 240 minutes. This relationship was not observed for knee-chest and other surgical positions. CONCLUSIONS This work presents a systematic review of positioning-related complications following prone, knee-chest, and other positions used for lumbar spine surgery. Numerous evidence-based recommendations for avoidance of these potentially severe complications associated with intraoperative positioning are discussed. This investigation may serve as a framework to educate the surgical team and decrease rates of intraoperative positioning complications.

Complications and Outcomes for Surgical Approaches to Cervical Kyphosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The primary objective of this study is to report the safety and efficacy of the different surgical approaches to cervical deformity correction surgery. SUMMARY OF BACKGROUND DATA: Cervical subaxial deformity surgery has been shown to be an effective means to alleviate pain and improve neurological function in symptomatic patients. The reported outcomes and complications for the different surgical approaches (ventral, dorsal, and combined) are limited to small retrospective studies. The appropriate surgical approach is at times unclear, which is likely attributed to the overlap in indications for the ventral and combined approach. MATERIALS AND METHODS: A retrospective review of 76 patients who underwent cervical deformity surgery for cervical kyphosis at 1 institution was performed. The authors reviewed the complications, radiographic outcomes, and long-term functional outcomes for all patients. RESULTS: The majority of patients in all groups reported excellent (15%) or good (50%) outcomes, with a mean improvement in modified Japanese orthopedic association score of 1.3. There were 26 perioperative complications (34%) for 19 patients (25%). We found the ventral-alone and combined approaches to achieve similar degrees of correction (23.1 and 23.2 degrees, respectively). The combined approach had the highest complication rate of the 3 approaches (combined: 40%, ventral: 30%, dorsal: 27%). The dorsal, ventral, and combined approaches had a mean neurological improvement in modified Japanese orthopedic association scores of 1.95, 3.00, and 1.26, respectively, and mean pain improvement of 0.8, 2.0, and 1.4. CONCLUSIONS: Given the moderate improvements in long-term outcomes, and the risks for perioperative complications, we recommend a careful selection process for patients eligible for cervical deformity surgery. We found that the ventral approach has reduced complications, similar degree of correction capability, and potentially higher improved neurological outcomes compared to the combined approach.

Adverse Events With the Use of rhBMP-2 in Thoracolumbar and Lumbar Spine Fusions: A 9-Year Institutional Analysis.

STUDY DESIGN: Retrospective chart review. OBJECTIVE: To describe the adverse outcomes associated with the use of rhBMP-2 in thoracolumbar and lumbar fusions. SUMMARY OF BACKGROUND DATA: rhBMP-2 has been increasingly used in spinal fusions over the past decade. Early studies reported that the use of rhBMP-2 is associated with decreased operative time, blood loss, and pain scores, as well as improved fusion rates. Recent investigations have shown rhBMP-2 to be associated with various complications occurring at incidences ranging from 0% to 100%. METHODS: Using the institutional electronic medical records, we retrospectively reviewed all patients between January 2002 and September 2010 that underwent thoracolumbar and lumbar spine fusion with BMP. Patient demographics, operative, and outcome/complication information was collected. RESULTS: A total of 547 patient charts were reviewed with a mean follow-up time of 17 months. Mean age was 58 years. Forty-one percent of patients had undergone previous spine surgery. Thirty-nine percent of patients had a PLIF/TLIF, 29% underwent a PLF, and 20% an ALIF. No relevant differences in the patient characteristics and complications were identified between the various surgical approaches. For all approaches, having undergone a previous spine surgery was associated with increased incidence of radiculitis, reoperation, and pseudoarthrosis (P=0.005, 0.0008, 0.05, respectively) as compared with those without previous spine surgery. Being a current smoker at the time of operation was associated with increased rate of radiculitis (P=0.03) as compared with nonsmokers. CONCLUSIONS: The use of rhBMP-2, in this study, had an incidence of radiculitis, pseudoarthrosis, and reoperation that was similar to the rates in historical controls without rhBMP-2. Complications do not differ by surgical approach, but are more likely in current smokers and those undergoing revision surgery. A prospective study is warranted to further delineate the adverse event profile of rhBMP-2 and the variables that are likely to affect it (ie, type of surgery, carrier, and dose).

An institutional series and contemporary review of bacterial spinal epidural abscess: current status and future directions.

OBJECT: Over the past decade, the incidence of bacterial spinal epidural abscess (SEA) has been increasing. In recent years, studies on this condition have been rampant in the literature. The authors present an 11-year institutional experience with SEA patients. Additionally, through an analysis of the contemporary literature, they provide an update on the challenging and controversial nature of this increasingly encountered condition. METHODS: An electronic medical record database was used to retrospectively analyze patients admitted with SEA from January 2001 through February 2012. Presenting symptoms, concurrent conditions, microorganisms, diagnostic modalities, treatments, and outcomes were examined. For the literature search, PubMed was used as the search engine. Studies published from January 1, 2000, through December 31, 2013, were critically reviewed. Data from articles on methodology, demographics, treatments, and outcomes were recorded. RESULTS: A total of 106 patients with bacterial SEA were identified. The mean ± SD age of patients was 63.3 ± 13.7 years, and 65.1% of patients were male. Common presenting signs and symptoms were back pain (47.1%) and focal neurological deficits (47.1%). Over 75% of SEAs were in the thoracolumbar spine, and over 50% were ventral. Approximately 34% had an infectious origin. Concurrent conditions included diabetes mellitus (35.8%), vascular conditions (31.3%), and renal insufficiency/dialysis (30.2%). The most commonly isolated organism was Staphylococcus aureus (70.7%), followed by Streptococcus spp. (6.6%). Surgery along with antibiotics was the treatment for 63 (59.4%) patients. Surgery involved spinal fusion for 19 (30.2%), discectomy for 14 (22.2%), and corpectomy for 9 (14.3%). Outcomes were reported objectively; at a mean ± SD follow-up time of 8.4 ± 26 weeks (range 0-192 weeks), outcome was good for 60.7% of patients and poor for 39.3%. The literature search yielded 40 articles, and the authors discuss the result of these studies. CONCLUSIONS: Bacterial SEA is an ominous condition that calls for early recognition. Neurological status at the time of presentation is a key factor in decision making and patient outcome. In recent years, surgical treatment has been advocated for patients with neurological deficits and failed response to medical therapy. Surgery should be performed immediately and before 36-72 hours from onset of neurological sequelae. However, the decision between medical or surgical intervention entails individual patient considerations including age, concurrent conditions, and objective findings. An evidence-based algorithm for diagnosis and treatment is suggested.

Holospinal epidural abscess of the spinal axis: two illustrative cases with review of treatment strategies and surgical techniques.

Despite the increasing prevalence of spinal infections, the subcategory of holospinal epidural abscesses (HEAs) is extremely infrequent and requires unique management. Panspinal imaging (preferably MRI), modern aggressive antibiotic therapy, and prompt surgical intervention remain the standard of care for all spinal axis infections including HEAs; however, the surgical decision making on timing and extent of the procedure still remain ill defined for HEAs. Decompression including skip laminectomies or laminoplasties is described, with varied clinical outcomes. In this review the authors present the illustrative cases of 2 patients with HEAs who were treated using skip laminectomies and epidural catheter irrigation techniques. The discussion highlights different management strategies including the role of conservative (nonsurgical) management in these lesions, especially with an already identified pathogen and the absence of mass effect on MRI or significant neurological defects. Among fewer than 25 case reports of HEA published in the past 25 years, the most important aspect in deciding a role for surgery is the neurological examination. Nearly 20% were treated successfully with medical therapy alone if neurologically intact. None of the reported cases had an associated cranial infection with HEA, because the dural adhesion around the foramen magnum prevented rostral spread of infection. Traditionally a posterior approach to the epidural space with irrigation is performed, unless an extensive focal ventral collection is causing cord compression. Surgical intervention for HEA should be an adjuvant treatment strategy for all acutely deteriorating patients, whereas aspiration of other infected sites like a psoas abscess can determine an infective pathogen, and appropriate antibiotic treatment may avoid surgical intervention in the neurologically intact patient.

Ergonomics, musculoskeletal disorders, and surgeon gender in spine surgery: a survey of practicing spine surgeons.

OBJECTIVE: The objective of this study was to gain a greater understanding of the burden of musculoskeletal disorders (MSDs) in spine surgeons, their impact on practice, and risk factors contributing to MSDs, including surgical instrument design and surgical ergonomics. METHODS: An anonymous REDCap survey was distributed via email to the departments of several academic and private centers across the United States, as well as to the AANS/CNS Women in Neurosurgery Section email list. Chi-square tests and Wilcoxon rank-sum tests were used to compare responses by gender. Multivariable linear regression analysis was performed to identify predictors of discomfort in instrument utilization. RESULTS: Survey responses were received from 120 spine surgeons (29.1% response rate), of which 73 were included in the analysis. A very high number of respondents had experienced an MSD (70.4%), 38.2% had undergone treatment for at least one MSD, and 13.4% had lost time at work for at least one MSD. Women were more likely than men to have lost time at work due to an MSD (22.6% vs 5.6%, p = 0.04). Women were more likely than men to report difficulty in instrument grip, comfort, and use on a 20-point Likert scale (mean 10.7 vs 15.2 points, p < 0.0001). This effect persisted when adjusting for glove size and days per week spent operating (p = 0.002). Specifically, women were less likely to agree that the handles of surgical instruments were an appropriate grip (p < 0.0001), that they rarely experienced difficulty when using them (p < 0.0001), and that they rarely needed to use two hands with instruments meant to be used with one hand (p = 0.0002). CONCLUSIONS: The MSD burden in spine surgeons is substantial. While there was no evidence of gender differences in MSD rates and severity, female surgeons report significantly more discomfort with the use of surgical instruments. There is a need for more investigation of MSD risk factors in spine surgeons and mitigation strategies. Gender differences in comfort in instrument use should be further explored and addressed by spine surgeons and device manufacturers.

C1-2 hypermobility and its impact on the spinal cord: a finite element analysis.

OBJECTIVE: The authors present a finite element analysis (FEA) evaluating the mechanical impact of C1-2 hypermobility on the spinal cord. METHODS: The Code_Aster program was used to perform an FEA to determine the mechanical impact of C1-2 hypermobility on the spinal cord. Normative values of Young's modulus were applied to the various components of the model, including bone, ligaments, and gray and white matter. Two models were created: 25° and 50° of C1-on-C2 rotation, and 2.5 and 5 mm of C1-on-C2 lateral translation. Maximum von Mises stress (VMS) throughout the cervicomedullary junction was calculated and analyzed. RESULTS: The FEA model of 2.5 mm lateral translation of C1 on C2 revealed maximum VMS for gray and white matter of 0.041 and 0.097 MPa, respectively. In the 5-mm translation model, the maximum VMS for gray and white matter was 0.069 and 0.162 MPa. The FEA model of 25° of C1-on-C2 rotation revealed maximum VMS for gray and white matter of 0.052 and 0.123 MPa. In the 50° rotation model, the maximum VMS for gray and white matter was 0.113 and 0.264 MPa. CONCLUSIONS: This FEA revealed significant spinal cord stress during pathological rotation (50°) and lateral translation (5 mm) consistent with values found during severe spinal cord compression and in patients with myelopathy. While this finite element model requires oversimplification of the atlantoaxial joint, the study provides biomechanical evidence that hypermobility within the C1-2 joint leads to pathological spinal cord stress.

Pedicle Subtraction Osteotomies for Surgical Correction of Fixed Sagittal Imbalance: A Meta-Analysis and Systematic Review.

BACKGROUND AND OBJECTIVES: Disruption of the spine's sagittal balance is associated with significant negative impacts on quality of life. Compared with other spinal osteotomies, pedicle subtraction osteotomy (PSO), which can potentially offer greater correction, is considered technically challenging and performed at lower rates. The aim of this study was to review the use of PSO to correct fixed sagittal imbalance and assess its efficacy and associated perioperative complications. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the PubMed, EBSCO host, MEDLINE, and Google Scholar databases were queried for full-text English manuscripts published from 1961 to 2022, exploring PSO for the management of fixed sagittal imbalance. Studies were included if they reported preoperative and postoperative radiographic measurements. The mean Methodological Index for Nonrandomized Studies (MINORS) for included articles was 9.6 ± 1.1. The outcomes of interest included etiology, operative time, blood loss, complications, radiographic outcomes, and patient-reported outcomes. Statistical analysis was performed using a random-effects, inverse variance-weighted meta-analysis of observational data. Pre and postoperative radiographic and clinical outcomes were compared using a Student t-test. RESULTS: Fourteen studies with 595 patients were included. Meta-analysis showed that the mean operative time was 7.2 ± 2.0 hours, and the average blood loss was 2033 ± 629 mL. After PSO, there was a significant improvement in sagittal vertebral axis (12.41-3.92 cm, P = .0003), LL (13.35°-42.60°, P = .000002), PSO angle (5.11° to -26.91°, P = .0001), and Oswestry Disability Index (55.36-27.35, P = .02). Common complications include pseudarthrosis (8.1%), neurological deficits (7.8%), and proximal junctional failure (6.0%). CONCLUSION: PSO offers significant correction of sagittal vertebral axis, lumbar lordosis, PSO angle, and Oswestry Disability Index scores despite its reduced utilization in recent years. Blood loss and high complication rates must be considered when evaluating the efficacy of this procedure; however, surgeon experience and operative techniques can be used to reduce morbidity.

Correction: The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis).

[This corrects the article DOI: 10.1371/journal.pone.0274634.].

Histologic Assessment of Lumbosacral Transitional Vertebrae Pseudoarticulation as a Source of Pain in Bertolotti Syndrome.

BACKGROUND: Bertolotti syndrome (BS) is characterized by chronic pain and functional impairment associated with lumbosacral transitional vertebrae (LSTVs). The study aimed to investigate the histologic characteristics of the pseudoarticulation between the enlarged transverse process and sacrum seen in Castellvi 2a LSTV and explore the involvement of nervous tissue in pain generation. METHODS: Immunohistochemical analysis using S100 protein staining was performed to assess the presence of nerve tissue. RESULTS: These changes included fibrillation, chondrocyte cloning, alterations in the proteoglycan matrix, and focal chondrocyte necrosis. Notably, no nerve tissue was observed in any of the specimens, as confirmed by negative S100 protein staining. CONCLUSIONS: The study findings suggest that nerve tissue is not involved in the nociceptive mechanisms underlying pain in BS. The histologic similarities between the pseudoarticulation and osteoarthritic joints indicate that pseudoarticulation itself may be a significant source of pain in BS. These insights contribute to our understanding of the pathophysiology of BS and support treatment paradigms prioritizing pain control with medications such as NSAIDs before considering surgical intervention. Future studies with larger sample sizes and in vivo models are needed to further validate these findings and explore the changes in joint histology under biomechanical forces in LSTVs.

Review of mechanisms of expandable spine surgery devices.

INTRODUCTION: Expandable devices such as interbody cages, vertebral body reconstruction cages, and intravertebral body expansion devices are frequently utilized in spine surgery. Since the introduction of expandable implants in the early 2000s, the variety of mechanisms that drive expansion and implant materials have steadily increased. By examining expandable devices that have achieved commercial success and exploring emerging innovations, we aim to offer an in-depth evaluation of the different types of expandable cages used in spine surgery and the underlying mechanisms that drive their functionality. AREAS COVERED: We performed a review of expandable spinal implants and devices by querying the National Library of Medicine MEDLINE database and Google Patents database from 1933 to 2024. Five major types of mechanical jacks that drive expansion were identified: scissor, pneumatic, screw, ratchet, and insertion-expansion. EXPERT OPINION: We identified a trend of screw jack mechanism being the predominant machinery in vertebral body reconstruction cages and scissor jack mechanism predominating in interbody cages. Pneumatic jacks were most commonly found in kyphoplasty devices. Critically reviewing the mechanisms of expansion and identifying trends among effective and successful cages allows both surgeons and medical device companies to properly identify future areas of development.

Factors affecting retirement and workforce attrition in neurosurgery: results of a Council of State Neurosurgical Societies national survey.

OBJECTIVE: By 2030, the US will not have enough neurosurgeons to meet the clinical needs of its citizens. Replacement of neurosurgeons due to attrition can take more than a decade, given the time-intensive training process. To identify potential workforce retention targets, the authors sought to identify factors that might impact neurosurgeons' retirement considerations. METHODS: The Council of State Neurosurgical Societies surveyed practicing AANS-registered neurosurgeons via email link to an online form with 25 factors that were ranked using a Likert scale of importance regarding retirement from the field (ranging from 1 for not important to 3 for very important). All participants were asked: "If you could afford it, would you retire today?" RESULTS: A total of 447 of 3200 neurosurgeons (14%) responded; 6% had been in practice for less than 5 years, 19% for 6-15 years, 57% for 16-30 years, and 18% for more than 30 years. Practice types included academic (18%), hospital employed (31%), independent with academic appointment (9%), and full independent practice (39%). The most common practice size was between 2 and 5 physicians (46%), with groups of 10 or more being the next most common (20%). Career satisfaction, income, and the needs of patients were rated as the most important factors keeping neurosurgeons in the workforce. Increasing regulatory burden, decreasing clinical autonomy, and the burden of insurance companies were the highest rated for factors important in considering retirement. Subgroup analysis by career stage, practice size, practice type, and geographic region revealed no significant difference in responses. When considering if they would retire now, 45% of respondents answered "yes." Subgroup analysis revealed that midcareer neurosurgeons (16-25 years in practice) were more likely to respond "yes" than those just entering their careers or in practice for more than 25 years (p = 0.03). This effect was confirmed in multivariate logistic regression (p = 0.04). These surgeons found professional satisfaction (p = 0.001), recertification requirements (p < 0.001), and maintaining high levels of income (p = 0.008) important to maintaining employment within the neurosurgical workforce. CONCLUSIONS: This study demonstrates that midcareer neurosurgeons may benefit from targeted retention efforts. This effort should focus on maximizing professional satisfaction and financial independence, while decreasing the regulatory burden associated with certification and insurance authorization. End-of-career surgeons should be surveyed to determine factors contributing to resilience and persistence within the neurosurgical workforce.

Radiographic Alignment Parameters for Lumbosacral Reconstruction in Patients With Altered S1 Morphology.

STUDY DESIGN: Retrospective quantitative analysis study. OBJECTIVES: Pelvic incidence has been established as central radiographic marker which determines patient-specific correction goals during surgery for adult spinal deformity. In cases with sacral doming or sacral osteotomy where the PI cannot be calculated, reliable radiographic parameters need to be established to determine surgical goals. We aim to determine multiple radiographic parameters and formulas that can be utilized when the S1 superior endplate is obscured. METHODS: Retrospective analysis was performed on 68 healthy volunteers without prior spine surgery with full-length radiographs. Pelvic incidence, sacral slope, and pelvic tilt were calculated for each patient. Additional measurements such as L4, L5, and S2 incidence, tilt, and slope were collected. A new radiographic parameter defined as the L4-Sciatic notch angle was measured. Regression analysis was performed on each value to determine its relationship with S1 based incidence, tilt, and slope. RESULTS: Mean values for L5 incidence, L4 incidence, and L4 sciatic notch angle were 21.8° ± 8.9, 4.4° ± 8.1, and 44.4° ± 12, respectively. The linear regression analysis produced the following formulas which can be utilized to determine deformity correction goals when pelvic incidence can be calculated pre-operatively: L5i = .65*S1i-11.4, L4i = .44*S1i-18.6, and L4SNA = -.34*S1i + 66.5. In settings where pelvic incidence cannot be calculated, the following formulas can be utilized: L5i = .66*S2i-32.3 and L4SNA = -.02*S2i2 + 1.1*S2i + 63.5. P-values for all regression analyses were <.001. CONCLUSION: This study provides target radiographic alignment values that can be utilized for patients with either pre-operative altered S1 endplates or in cases with intraoperative alteration of S1 (sacral osteotomy).

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.