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.

Students choosing fat-free chocolate milk during school lunch consume more calories, total sugar, protein, minerals and vitamins at lunch.

OBJECTIVE: To examine how milk consumption varies by milk choice and measure the association of milk choice on the nutritional and energetic content of National School Lunch Program (NSLP) lunches. DESIGN: An observational plate waste study using the Digital Photography of Foods Method. SETTING: Data were collected from two suburban South Carolina schools in one district during February and March 2013. PARTICIPANTS: Totally, 968 NSLP lunches selected by 619 kindergarten to fifth grade students. RESULTS: Most students chose chocolate milk (75 %). A multinomial logit model indicated milk choice varied significantly by sociodemographic characteristics. An ordinary least square regression indicated that consumption rates of low-fat white milk were 8·5 % lower than fat-free chocolate milk (P = 0·039) and milk consumption rates varied statistically by sociodemographic characteristics. Ordinary least square regressions found that the consumption of energies and nutrients from NSLP lunches varied with sociodemographic characteristics and milk choice; students selecting chocolate milk consumed 58 more energies (P < 0·001) and 10 more grams of total sugar (P < 0·001) than students selecting low-fat white milk from their NSLP lunches. Students consumed statistically similar energies and nutrients from the non-milk components of their meals. CONCLUSIONS: Students selecting chocolate milk consumed more energies and nutrients from their NSLP lunches with the increases in consumption attributed to the milk component of the meal. The findings have implications for recent changes to NSLP guidelines that allow schools to offer both low-fat and fat-free flavoured milk, reversing the previous ban on low-fat flavoured milk under the Healthy, Hunger-Free Kids Act.

Selection and consumption of lunches by National School Lunch Program participants.

The Healthy, Hunger-Free Kids Act of 2010 requires schools participating in the National School Lunch Program (NSLP) to offer a variety of healthy food options each day. Using digital photography data collected from two suburban elementary schools in the spring of 2013, we examine NSLP participant's selection and consumption of all five NSLP lunch components ((1) milk, (2) vegetable, (3) fruit, (4) meat/meat alternate (MA), and (5) grain). We use logit regressions to analyze the selection of the various lunch components by race/ethnicity, gender, grade, and household income level. In addition, ordinary least squares regressions are used to analyze the selection and consumption of calories contained in the chosen lunch and by lunch component. Selection and consumption varied by race, ethnicity, gender, and eligibility for free or reduced-price lunch. For example, black students consumed fewer calories than white students, black and Hispanic students consumed fewer calories from milk than white students, and free and reduced-price lunch eligible students consumed more calories from milk and fewer calories from grains. Using National Health and Nutrition Examination Survey (NHANES) data, we determine that school lunches are an important part of school-day food intake for NSLP participants. These results provide guidance for making changes within a cafeteria's offerings to increase the selection of healthy foods.

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.

Methanogenic archaea in marcellus shale: a possible mechanism for enhanced gas recovery in unconventional shale resources.

Marcellus Shale occurs at depths of 1.5-2.5 km (5000 to 8000 feet) where most geologists generally assume that thermogenic processes are the only source of natural gas. However, methanogens in produced fluids and isotopic signatures of biogenic methane in this deep shale have recently been discovered. This study explores whether those methanogens are indigenous to the shale or are introduced during drilling and hydraulic fracturing. DNA was extracted from Marcellus Shale core samples, preinjected fluids, and produced fluids and was analyzed using Miseq sequencing of 16s rRNA genes. Methanogens present in shale cores were similar to methanogens in produced fluids. No methanogens were detected in injected fluids, suggesting that this is an unlikely source and that they may be native to the shale itself. Bench-top methane production tests of shale core and produced fluids suggest that these organisms are alive and active under simulated reservoir conditions. Growth conditions designed to simulate the hydrofracture processes indicated somewhat increased methane production; however, fluids alone produced relatively little methane. Together, these results suggest that some biogenic methane may be produced in these wells and that hydrofracture fluids currently used to stimulate gas recovery could stimulate methanogens and their rate of producing methane.

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.

Lumbar microdiscectomy complication rates: a systematic review and meta-analysis.

OBJECT Lumbar microdiscectomy and its various minimally invasive surgical techniques are seeing increasing popularity, but a systematic review of their associated complications has yet to be performed. The authors sought to identify all prospective clinical studies reporting complications associated with lumbar open microdiscectomy, microendoscopic discectomy (MED), and percutaneous microdiscectomy. METHODS The authors conducted MEDLINE, Scopus, Web of Science, and Embase database searches for randomized controlled trials and prospective cohort studies reporting complications associated with open, microendoscopic, or percutaneous lumbar microdiscectomy. Studies with fewer than 10 patients and published before 1990 were excluded. Overall and interstudy median complication rates were calculated for each surgical technique. The authors also performed a meta-analysis of the reported complications to assess statistical significance across the various surgical techniques. RESULTS Of 9504 articles retrieved from the databases, 42 met inclusion criteria. Most studies screened were retrospective case series, limiting the number of studies that could be included. A total of 9 complication types were identified in the included studies, and these were analyzed across each of the surgical techniques. The rates of any complication across the included studies were 12.5%, 13.3%, and 10.8% for open, MED, and percutaneous microdiscectomy, respectively. New or worsening neurological deficit arose in 1.3%, 3.0%, and 1.6% of patients, while direct nerve root injury occurred at rates of 2.6%, 0.9%, and 1.1%, respectively. Hematoma was reported at rates of 0.5%, 1.2%, and 0.6%, respectively. Wound complications (infection, dehiscence, orseroma) occurred at rates of 2.1%, 1.2%, and 0.5%, respectively. The rates of recurrent disc complications were 4.4%, 3.1%, and 3.9%, while reoperation was indicated in 7.1%, 3.7%, and 10.2% of operations, respectively. Meta-analysis calculations revealed a statistically significant higher rate of intraoperative nerve root injury following percutaneous procedures relative to MED. No other significant differences were found. CONCLUSIONS This review highlights complication rates among various microdiscectomy techniques, which likely reflect real-world practice and conceptualization of complications among physicians. This investigation sets the framework for further discussions regarding microdiscectomy options and their associated complications during the informed consent process.

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).

Quality of life outcomes following surgery for patients with coexistent cervical stenosis and multiple sclerosis.

PURPOSE: To investigate the quality of life outcomes following surgical treatment of patients with coexisting multiple sclerosis (MS) and cervical stenosis with associated myelopathy (CS). METHODS: A retrospective review of the medical records and of prospectively acquired quality of life (QOL) data was performed for all patients with symptoms of myelopathy and coexisting diagnoses of MS and CS that underwent cervical decompression surgery between 2008 and 2011. The study population was matched (1:4) to a control cohort of patients that did not have MS but presented with similar myelopathic symptoms due to cervical stenosis, were of the same age and gender, and underwent the same cervical decompression procedure within the same year. RESULTS: Sixty-five patients were reviewed, including 13 in the MS group and 52 in the control group that were followed for an average of 22 and 18 months, respectively. Whereas patients in the MS cohort remained at a Quality-Adjusted Life-Year (QALY) gain of 0.51 both pre- and post-operatively (p = 0.96), patients in the matched control cohort improved from a preoperative QALY of 0.50 to a postoperative QALY of 0.64 (p < 0.0001). The latter represents an improvement that exceeds the minimum clinically important difference. Overall, 70% of patients in the control group experienced an improvement in QALY, compared to only 54% in the MS group (p = 0.4). CONCLUSION: Patients in the control cohort had clinically and statistically significant improvements in QALY outcomes. Those in the MS cohort averaged no change in QALY. However, only a minority of MS/CS patients had worsening QALY following surgery, and as such surgery may still be considered for these patients. It is imperative that there are preoperative discussions with the MS/CS patient regarding the likelihood that surgery will only provide limited, if any, improvements in QOL.

Variations in cost calculations in spine surgery cost-effectiveness research.

OBJECT: Cost-effectiveness research in spine surgery has been a prominent focus over the last decade. However, there has yet to be a standardized method developed for calculation of costs in such studies. This lack of a standardized costing methodology may lead to conflicting conclusions on the cost-effectiveness of an intervention for a specific diagnosis. The primary objective of this study was to systematically review all cost-effectiveness studies published on spine surgery and compare and contrast various costing methodologies used. METHODS: The authors performed a systematic review of the cost-effectiveness literature related to spine surgery. All cost-effectiveness analyses pertaining to spine surgery were identified using the cost-effectiveness analysis registry database of the Tufts Medical Center Institute for Clinical Research and Health Policy, and the MEDLINE database. Each article was reviewed to determine the study subject, methodology, and results. Data were collected from each study, including costs, interventions, cost calculation method, perspective of cost calculation, and definitions of direct and indirect costs if available. RESULTS: Thirty-seven cost-effectiveness studies on spine surgery were included in the present study. Twenty-seven (73%) of the studies involved the lumbar spine and the remaining 10 (27%) involved the cervical spine. Of the 37 studies, 13 (35%) used Medicare reimbursements, 12 (32%) used a case-costing database, 3 (8%) used cost-to-charge ratios (CCRs), 2 (5%) used a combination of Medicare reimbursements and CCRs, 3 (8%) used the United Kingdom National Health Service reimbursement system, 2 (5%) used a Dutch reimbursement system, 1 (3%) used the United Kingdom Department of Health data, and 1 (3%) used the Tricare Military Reimbursement system. Nineteen (51%) studies completed their cost analysis from the societal perspective, 11 (30%) from the hospital perspective, and 7 (19%) from the payer perspective. Of those studies with a societal perspective, 14 (38%) reported actual indirect costs. CONCLUSIONS: Changes in cost have a direct impact on the value equation for concluding whether an intervention is cost-effective. It is essential to develop a standardized, accurate means of calculating costs. Comparability and transparency are essential, such that studies can be compared properly and policy makers can be appropriately informed when making decisions for our health care system based on the results of these studies.

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.

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.

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.

Vascular injuries during anterior exposure of the thoracolumbar spine.

BACKGROUND: The aim of this study was to evaluate the vascular injuries, repairs, and complications encountered during anterior thoracolumbar spine exposures. METHODS: The medical records of patients undergoing anterior spine exposures from January 2004 to June 2010 were retrospectively analyzed. RESULTS: A total of 269 anterior exposures were performed in 260 patients. The average patient age was 50.1 years, and the average body mass index was 29.0. Female patients represented 146 (54.3%) cases. Previous spinal surgery was noted in 145 (53.9%) cases, and 19 (7.1%) had previous anterior exposure. The median estimated blood loss (EBL) was 300 mL, and there were no postoperative mortalities. A vascular injury occurred in 37 cases (13.8%), with redo anterior exposure (n = 19, 52% vs. 11%; P < 0.001), previous spinal surgery (n = 145, 19% vs. 7%; P = 0.01), and diagnosis of a tumor (n = 14, 36% vs. 12.5%; P = 0.03) being associated with increased vascular injury. A vascular injury resulted in greater EBL (median: 800 mL vs. 300 mL; P < 0.001) and longer hospitalization (median: 7 days vs. 5 days; P = 0.04). Most frequently injured was the left common iliac vein (in 21 of the 37 [52.5%] injured cases). A vascular surgeon performed the exposure in 159 (59.1%) cases. There was a decrease in EBL (250 mL vs. 500 mL; P < 0.001), total incision time (290 minutes vs. 404 minutes; P = 0.002), and length of stay (5 days vs. 6.5 days; P < 0.001) as compared with the operations where the vascular surgeon was not involved in the exposure. These cases also had an increased incidence of any vascular injury (28 vs. 9; P = 0.04). There were no differences between groups regarding vascular injury type, repair type, or the incidence of deep venous thrombosis. CONCLUSION: Collaboration between spine and vascular teams may result in decreased blood loss and consequently improved morbidity and length of hospital stay.

Ventral fusion versus dorsal fusion: determining the optimal treatment for cervical spondylotic myelopathy.

Cervical spondylotic myelopathy (CSM) often can be surgically treated by either ventral or dorsal decompression and fusion. However, there is a lack of high-level evidence on the relative advantages and disadvantages for these treatments of CSM. The authors' goal was to provide a comprehensive review of the relative benefits of ventral versus dorsal fusion in terms of quality of life (QOL) outcomes, complications, and costs. They reviewed 7 studies on CSM published between 2003 and 2013 and summarized the findings for each category. Both procedures have been shown to lead to statistically significant improvement in clinical outcomes for patients. Ventral fusion surgery has been shown to yield better QOL outcomes than dorsal fusion surgery. Complication rates for ventral fusion surgery range from 11% to 13.6%, whereas those for dorsal fusion surgery range from 16.4% to 19%. Larger randomized controlled trials are needed, with particular emphasis on QOL and minimum clinically important differences.

Lateral extracavitary, costotransversectomy, and transthoracic thoracotomy approaches to the thoracic spine: review of techniques and complications.

STUDY DESIGN: Systematic review. OBJECTIVE: The authors review complications, as reported in the literature, associated with ventral and posterolateral approaches to the thoracic spine. SUMMARY OF BACKGROUND: The lateral extracavitary, costotransversectomy, and transthoracic thoracotomy techniques allow surgeons to access the ventral thoracic spine for a wide range of spinal disorders including tumor, degeneration, trauma, and infection. Although the transthoracic thoracotomy has been used traditionally to reach the ventral thoracic spine when access to the vertebral body is required, modifications to the various dorsal approaches have enabled surgeons to achieve goals of decompression, reconstruction, and stabilization through a single approach. METHODS: A systematic Medline search from 1991 to 2011 was performed to identify series reporting clinical data related to these surgical approaches. The morbidity associated with each approach is reviewed and strategies for complications avoidance are discussed. RESULTS: Four thousand six hundred seventy-seven articles that assessed outcomes of the approaches to the thoracic spine were identified; of these 31 studies that consisted of 774 patients were selected for inclusion. A mean complication rate of 39%, 17%, and 15% for thoracotomy, lateral extracavitary, and costotransversectomy, respectively, was determined. The thoracotomy approach had the highest reoperation (3.5%) and mortality rates (1.5%). The specific complications and neurological outcomes were categorized. CONCLUSIONS: Outcomes of the surgical approaches to the thoracic spine have been reported with great detail in the literature. There are limited studies comparing the respective advantages and disadvantages and the differences in technique and outcome between these approaches. The present review suggests that in contrast to the historical experience of the laminectomy for thoracic spine disorders, these alternative approaches are safe and rarely associated with neurological deterioration. The differences between these approaches are based on their complication profiles. A thorough understanding of the regional anatomy will help avoid approach-related complications.

Circumferential cervical surgery: to stage or not to stage?

STUDY DESIGN: Retrospective review. OBJECTIVE: The objective of the study was to determine the morbidity and mortality rate associated with same day versus staged cervical circumferential approach. SUMMARY OF BACKGROUND DATA: A combined approach to the cervical spine is often indicated for complex cervical pathologies. Previous studies suggested superior results associated with same day combined surgery for thoracolumbar patients. This study examines the usefulness of p-Physiological and Operative Severity Score for enumeration of Morbidity and Mortality (POSSUM), an estimated mortality risk assessment for cervical spine patients and will compare same day surgery to staged procedures. METHODS: This is a retrospective chart review including patients who underwent ventral and dorsal approach within 2 weeks. Estimated mortality was calculated using p-POSSUM. The cohort was divided into same day surgery group and staged group. Risk factors were compared between groups. Mean p-POSSUM was calculated and compared with the actual mortality rate. Univariate analysis was used to compare the risk factors between groups and the groups' outcomes. Multivariable analysis was used to adjust for risk factor differences when comparing group outcomes. RESULTS: One hundred thirty-five patients were included, 106 patients were in the same day surgery group whereas 29 patients were in the staged group. Mean p-POSSUM was 2.8% predicted mortality with a 95% confidence interval of 1.6% to 4.1%. The actual mortality rate was 3.7%. The groups did not vary in most risk factors assessed. Univariate analysis demonstrated a statistically significantly higher rate of major complications (0.62 vs. 0.34, P=0.0369), infection (41.4% vs. 9.4%, P<0.0001), and length of hospital stay (9.3 vs. 6.8 d, P=0.0120) in the staged group. Multivariable analysis demonstrated significantly higher infection rate in the staged group. CONCLUSIONS: P-POSSUM mortality estimate may serve as a useful and valid tool for spine surgery studies. Staged combined cervical surgery harbors a higher complication rate and may be associated with lengthier hospitalization.