Metrics for Success in a Surgical Innovation Fellowship.

The nature of a dedicated research time during surgical residency has evolved from a traditional basic science laboratory experience to include translational and outcomes research, investigations in improving surgical education, secondary degrees, and other clinical fellowships as trainees have sought an increasingly wide range of experiences. Moreover, many surgical specialties have seen a burst of innovation with new devices, implants, tools, and software to improve the care of surgical patients and minimize complications. This environment has led to a surge in interest in innovation, often focused on surgical device development. Despite this groundswell of interest in innovation at the trainee and program level, there is little structure or curriculum available which outlines a formalized pathway for innovation within a surgical residency, nor is there information on how the success of that program may be evaluated. We present the model we developed for a Surgical Innovation Fellowship and propose means for evaluation of the success of that fellowship.

Descriptive epidemiology of chordomas in the United States.

PURPOSE: Chordomas account for 1% to 4% of all bone malignancies and 0.5% of all primary intracranial central nervous system tumors. Prior epidemiologic literature is based on limited population data. The purpose of this study is to provide the largest and most inclusive population based study of the descriptive epidemiology of chordomas. METHODS: The Centers for Disease Control and Prevention and National Program of Cancer Registries were queried for chordoma in all locations. Age-adjusted incidence per 100,000 persons was calculated by age, sex, race, and ethnicity. Annual percentage change was calculated using Joinpoint. RESULTS: From 2004 to 2014, a total of 3670 chordomas were diagnosed in the US. The most common location was cranial (38.7%), followed by sacral (34.3%) and spinal (27.0%). The average age-adjusted incidence rate was 0.088 per 100,000 persons per year (95% CI 0.086-0.091), with an annual percentage change of 1.29% (95% CI 0.31-2.28%). For all chordomas, the incidence peaks in the 75-84 year age group. The male-to-female incidence rate ratio is 1.54 (p < 0.001). American Indian/Alaskan Native and Black patients had a statistically lower incidence rate than White and Asian/Pacific Islander patients. CONCLUSION: Approximately 0.088 chordomas per 100,000 persons are newly diagnosed in the US each year, with cranial location being the most common, followed by sacral and spinal. Incidence increases with age, and men are at a significantly higher risk than women. This investigation represents the largest population-based epidemiologic study of chordomas in the US.

The epidemiology of central and extraventricular neurocytoma in the United States between 2006 and 2014.

INTRODUCTION: Central neurocytoma (CN) and extraventricular neurocytoma (EVN) are rare intracranial tumors. There is a paucity of studies reporting the population-based incidence of these tumors. We used the Central Brain Tumor Registry of the United States (CBTRUS), which contains the largest aggregation of population-based data on the incidence of primary central nervous system tumors in the United States to describe these tumors. METHODS: The CBTRUS database, provided by CDC representing approximately 100% of the US population, was queried using the following search criteria: diagnosis years 2006-2014, ICD-0-3 histology codes (9506/0: central neurocytoma, benign; 9506/1: central neurocytoma, uncertain). Annual age-adjusted incidence rates are presented per 100,000 population. Incidence was estimated by age, gender, race, and ethnicity. RESULTS: The combined overall annual incidence rate of CN and EVN was 0.032 [0.030-0.034]. The incidence rates were 0.022 [0.021-0.024] and 0.009 [0.008-0.010] for CN and EVN, respectively. The most frequently documented locations for EVN were frontal lobe and cerebellum, followed by temporal lobe. Peak incidence was found in the 20-34 years range for both CN and EVN. The incidence rate was slightly lower in males compared to females for CN and identical for EVN. The overall incidence rate of CN and EVN combined was lower in Blacks 0.026 [0.021-0.032] and Hispanic Whites 0.020 [0.016-0.025] compared to Non-Hispanic Whites 0.035 [0.033-0.038]. CONCLUSION: CN and EVN are rare tumors with a peak incidence in the 20-34 years age group. This study represents the largest population-based epidemiological study on CN and EVN in the US.

Techniques for placement of stereotactic electroencephalographic depth electrodes: Comparison of implantation and tracking accuracies in a cadaveric human study.

OBJECTIVE: Stereotactic electroencephalography (SEEG) is used for the evaluation and identification of the epileptogenic zone (EZ) in patients suffering from medically refractory seizures and relies upon the accurate implantation of depth electrodes. Accurate implantation is critical for identification of the EZ. Multiple electrodes and implantation systems exist, but these have not previously been systematically evaluated for implantation accuracy. This study compares the accuracy of two SEEG electrode implantation methods. METHODS: Thirteen "technique 1" electrodes (applying guiding bolts and external stylets) and 13 "technique 2" electrodes (without guiding bolts and external stylets) were implanted into four cadaver heads (52 total of each) according to each product's instructions for use using a stereotactic robot. Postimplantation computed tomography scans were compared to preimplantation computed tomography scans and to the previously defined targets. Electrode entry and final depth location were measured by Euclidean coordinates. The mean errors of each technique were compared using linear mixed effects models. RESULTS: Primary analysis revealed that the mean error difference of the technique 1 and 2 electrodes at entry and target favored the technique 1 electrode implantation accuracy (P < 0.001). Secondary analysis demonstrated that orthogonal implantation trajectories were more accurate than oblique trajectories at entry for technique 1 electrodes (P = 0.002). Furthermore, deep implantations were significantly less accurate than shallow implantations for technique 2 electrodes (P = 0.005), but not for technique 1 electrodes (P = 0.50). SIGNIFICANCE: Technique 1 displays greater accuracy following SEEG electrode implantation into human cadaver heads. Increased implantation accuracy may lead to increased success in identifying the EZ and increased seizure freedom rates following surgery.

Subsequent Pulse Generator Replacement Surgery Does Not Increase the Infection Rate in Patients With Deep Brain Stimulator Systems: A Review of 1537 Unique Implants at a Single Center.

INTRODUCTION: Deep brain stimulation (DBS) is a well-recognized treatment for patients with movement disorders and other neurological diseases. The implantable pulse generator (IPG) is a fundamental component of the DBS system. Although IPG implantation and replacement surgeries are comparatively minor procedures relative to the brain lead insertion, patients often require multiple IPG replacements during their lifetime with each operation carrying a small but possibly cumulative risk of complications. To better educate our patients and improve surgical outcomes, we reviewed our series of patients at our institution. METHODS: Using electronic health record data, we retrospectively reviewed all initial and subsequent IPG surgeries from patients who underwent at least one IPG surgery between the years of 2010 and 2015 at the Cleveland Clinic main campus. We calculated infection rates for initial IPG implantation surgeries and the infection rate for subsequent replacements. Fisher's exact tests were used to evaluate the chance of an infection between the initial implantation and replacement. Fisher's exact tests and simple logistic regression analyses were used to determine the predictive ability of selected demographic and clinical variables RESULTS: Our final sample included 697 patients and 1537 surgeries. For all patients, the infection rate at the first surgery was 2.01%; at the second surgery, it was 0.44%; and at the third surgery, it was 1.83%. When considering only patients that underwent at least three replacement surgeries (n = 114) the infection rate did not change in a significant manner with subsequent interventions compared to the first replacement. No other variable of interest was a significant predictor of infection. CONCLUSION: We did not find increasing rates of infection with subsequent IPG replacement procedures.

Transcutaneous electrical nerve stimulation for the treatment of acute postoperative pain following spine surgery: a scoping review.

OBJECTIVE: Given the ubiquity and severity of postoperative pain following spine surgery, developing adequate pain management modalities is critical. Transcutaneous electrical nerve stimulation (TENS) is a promising noninvasive modality that is well studied for managing postoperative pain following a variety of surgeries, but data on using TENS for pain management in the acute postoperative period of spine surgery are limited. Therefore, this review aimed to recapitulate the existing evidence for the use of TENS in postoperative pain management for spine surgery and explore the potential of this modality moving forward. METHODS: A scoping review was conducted according to 2020 PRISMA guidelines. Two independently operating reviewers then conducted a systematic search of PubMed, Embase, and Scopus databases to identify studies that reported the use of TENS for the treatment of acute postoperative pain following spine surgery. The following data were abstracted from included studies: study type, sample size, demographics, surgery details, comparison group, assessment parameters, timing of postoperative assessment, TENS technical characteristics, relevant findings, length of hospital stay, complications with TENS, and notable limitations. RESULTS: Nine hundred thirty-two publications were screened, resulting in 6 studies included in this review, all of which were prospective clinical trials. The publication dates ranged from 1980 to 2011. Spine surgery types varied; the most common was posterior lumbar interbody fusion. No studies evaluated pain control in cervical- or thoracic-only surgeries. All 6 studies evaluated the level of postoperative pain directly. Five of the 6 studies that directly examined postoperative pain reported lower levels of pharmacological analgesia usage in the TENS groups compared with controls, with 4 of these studies reporting this difference as statistically significant. Length of hospital stay was evaluated in 2 studies, both of which reported decreases in mean length of stay, but these differences were not significant. Notably, every study reported distinct TENS administration parameters while also reporting similar results. CONCLUSIONS: This review concludes that TENS is effective at reducing postoperative pain in spine surgery. Further investigation is needed regarding the optimal settings for TENS administration, as well as efficacy in the thoracic and cervical spine.

Development and validation of an artificial intelligence model to accurately predict spinopelvic parameters.

OBJECTIVE: Achieving appropriate spinopelvic alignment has been shown to be associated with improved clinical symptoms. However, measurement of spinopelvic radiographic parameters is time-intensive and interobserver reliability is a concern. Automated measurement tools have the promise of rapid and consistent measurements, but existing tools are still limited to some degree by manual user-entry requirements. This study presents a novel artificial intelligence (AI) tool called SpinePose that automatically predicts spinopelvic parameters with high accuracy without the need for manual entry. METHODS: SpinePose was trained and validated on 761 sagittal whole-spine radiographs to predict the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), T1 pelvic angle (T1PA), and L1 pelvic angle (L1PA). A separate test set of 40 radiographs was labeled by four reviewers, including fellowship-trained spine surgeons and a fellowship-trained radiologist with neuroradiology subspecialty certification. Median errors relative to the most senior reviewer were calculated to determine model accuracy on test images. Intraclass correlation coefficients (ICCs) were used to assess interrater reliability. RESULTS: SpinePose exhibited the following median (interquartile range) parameter errors: SVA 2.2 mm (2.3 mm) (p = 0.93), PT 1.3° (1.2°) (p = 0.48), SS 1.7° (2.2°) (p = 0.64), PI 2.2° (2.1°) (p = 0.24), LL 2.6° (4.0°) (p = 0.89), T1PA 1.1° (0.9°) (p = 0.42), and L1PA 1.4° (1.6°) (p = 0.49). Model predictions also exhibited excellent reliability at all parameters (ICC 0.91-1.0). CONCLUSIONS: SpinePose accurately predicted spinopelvic parameters with excellent reliability comparable to that of fellowship-trained spine surgeons and neuroradiologists. Utilization of predictive AI tools in spinal imaging can substantially aid in patient selection and surgical planning.

Conservative management of intraventricular migration of a gelatin sponge: illustrative case.

BACKGROUND: Gelatin sponges, such as Gelfoam, are used as hemostatic agents during surgery and are generally absorbed over the course of 4-6 weeks in most body cavities. The time course of the dissolution of Gelfoam sponges within the cerebral ventricles has not been described. OBSERVATIONS: The authors present a case of intraventricular migration of Gelfoam after ventriculoperitoneal shunt placement in a 6-week-old infant. The infant was imaged regularly after ventriculoperitoneal shunt placement, and the Gelfoam sponge persisted within the ventricles on all images until 11 months after surgery. At no time during follow-up did the patient have any symptoms of hydrocephalus requiring retrieval of the sponge or shunt revision. LESSONS: This is the first case describing time until absorption of a gelatin sponge within the ventricle and successful conservative management.

A comprehensive epidemiological review of spinal astrocytomas in the United States.

OBJECTIVE: Spinal cord astrocytoma (SCA) is a rare tumor whose epidemiology has not been well defined. The authors utilized the Central Brain Tumor Registry of the United States (CBTRUS) to provide comprehensive up-to-date epidemiological data for this disease. METHODS: The CBTRUS was queried for SCAs on ICD-O-3 (International Classification of Diseases for Oncology, 3rd edition) histological and topographical codes. The age-adjusted incidence (AAI) per 100,000 persons was calculated and stratified by race, sex, age, and ethnicity. Joinpoint was used to calculate the annual percentage change (APC) in incidence. RESULTS: Two thousand nine hundred sixty-nine SCAs were diagnosed in the US between 1995 and 2016, resulting in an average of approximately 136 SCAs annually. The overall AAI was 0.047 (95% CI 0.045-0.049), and there was a statistically significant increase from 0.051 in 1995 to 0.043 in 2016. The peak incidence of 0.064 (95% CI 0.060-0.067) was found in the 0- to 19-year age group. The incidence in males was 0.053 (95% CI 0.050-0.055), which was significantly greater than the incidence in females (0.041, 95% CI 0.039-0.044). SCA incidence was significantly lower both in patients of Asian/Pacific Islander race (AAI = 0.034, 95% CI 0.028-0.042, p = 0.00015) and in patients of Hispanic ethnicity (AAI = 0.035, 95% CI 0.031-0.039, p < 0.001). The incidence of WHO grade I SCAs was significantly higher than those of WHO grade II, III, or IV SCAs (p < 0.001). CONCLUSIONS: The overall AAI of SCA from 1995 to 2016 was 0.047 per 100,000. The incidence peaked early in life for both sexes, reached a nadir between 20 and 34 years of age for males and between 35 and 44 years of age for females, and then slowly increased throughout adulthood, with a greater incidence in males. Pilocytic astrocytomas were the most common SCA in the study cohort. This study presents the most comprehensive epidemiological study of SCA incidence in the US to date.

Predictors of favorable quality of life outcome following kyphoplasty and vertebroplasty.

OBJECTIVE: In 2009, 2 randomized controlled trials demonstrated no improvement in pain following vertebral augmentation compared with sham surgery. However, a recent randomized trial demonstrated significant pain relief in patients following vertebroplasty compared to controls treated with conservative medical management. This study is a retrospective review of prospectively collected patient-reported quality of life (QOL) outcomes. The authors hypothesized that vertebral augmentation procedures offer a QOL benefit, but that this benefit would be diminished in patients with a history of depression and/or in patients undergoing vertebral augmentation at more than 1 level. METHODS: Multivariable linear regression was used to identify predictors of postoperative pain assessed using the Pain Disability Questionnaire (PDQ), Patient Health Questionnaire 9 (PHQ-9), and EQ-5D scores. Eleven candidate predictors were selected a priori: age, sex, smoking history, coronary artery disease, depression, diabetes, procedure location (thoracic, lumbar), BMI, prior spine surgery, procedure indication (metastases, osteoporosis/osteopenia, other), and number of levels (1, 2, 3, or more). RESULTS: A total of 143 patients were included in the study. For each 10-year increase in age, postoperative PDQ scores decreased (improved) by 9.7 points (p < 0.001). Patients with osteoporosis/osteopenia had significantly higher (worse) postoperative PDQ scores (+17.97, p = 0.028) than patients with metastatic lesions. Male sex was associated with higher (worse) postoperative PHQ-9 scores (+2.48, p = 0.010). Compared to single-level augmentation, operations at 2 levels were associated with significantly higher PHQ-9 scores (+2.58, p = 0.017). Current smokers had significantly lower PHQ-9 scores (-1.98, p = 0.023) than never smokers. No predictors were associated with significantly different EQ-5D score. CONCLUSIONS: Variables associated with worse postoperative PDQ scores included younger age and osteoporosis/osteopenia. Variables associated with decreased (better) postoperative PHQ-9 scores included female sex, single operative vertebral level, and positive smoking status (i.e., current smoker). These clinically relevant predictors may permit identification of patients who may benefit from vertebral augmentation.

Early outcomes after intrathecal baclofen therapy in ambulatory patients with multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is a chronic autoimmune disease that causes demyelination and axonal loss. Walking difficulties are a common and debilitating symptom of MS; they are usually caused by spastic paresis of the lower extremities. Although intrathecal baclofen (ITB) therapy has been reported to be an effective treatment for spasticity in MS, there is limited published evidence regarding its effects on ambulation. The goal of this study was to characterize ITB therapy outcomes in ambulatory patients with MS. METHODS: Data from 47 ambulatory patients with MS who received ITB therapy were analyzed retrospectively. Outcome measures included Modified Ashworth Scale, Spasm Frequency Scale, Numeric Pain Rating Scale, and the Timed 25-Foot Walk. Repeated-measures ANOVA was used to test for changes in outcome measures between baseline and posttreatment (6 months and 1 year). Significance was set at p < 0.05. Descriptive data are expressed as the mean ± SD, and results of the repeated-measures ANOVA tests and the Wilcoxon rank-sum test are expressed as the mean ± SEM. RESULTS: There was a statistically significant reduction in the following variables: 1) aggregate lower-extremity Modified Ashworth Scale scores (from 14.8 ± 1.0 before ITB therapy to 5.8 ± 0.8 at 6 months posttreatment and 6.4 ± 0.9 at 1 year [p < 0.05]); 2) Numeric Pain Rating Scale scores (4.4 ± 0.5 before ITB, 2.8 ± 0.5 at 6 months, and 2.4 ± 0.4 at 1 year [p < 0.05]); 3) spasm frequency (45.7% of the patients reported a spasm frequency of ≥ 1 event per hour before ITB therapy, whereas 15.6% and 4.3% of the patients reported the same at 6 months and 1 year posttreatment, respectively [p < 0.05]); and 4) the number of oral medications taken for spasticity (p < 0.05). Of the 47 patients, 34 remained ambulatory at 6 months, and 32 at 1 year posttreatment. There was no statistically significant change in performance on the Timed 25-Foot Walk test over time for those patients who remained ambulatory. CONCLUSIONS: In this retrospective study, the authors found that ITB therapy is effective in reducing spasticity and related symptoms in ambulatory patients with MS. Because the use of ITB therapy is increasing in ambulatory patients with MS, randomized, prospective studies are important to help provide a more useful characterization of the effects of ITB therapy on ambulation.

The Role of Associative Cortices and Hippocampus during Movement Perturbations.

Although motor control has been extensively studied, most research involving neural recordings has focused on primary motor cortex, pre-motor cortex, supplementary motor area, and cerebellum. These regions are involved during normal movements, however, associative cortices and hippocampus are also likely involved during perturbed movements as one must detect the unexpected disturbance, inhibit the previous motor plan, and create a new plan to compensate. Minimal data is available on these brain regions during such "robust" movements. Here, epileptic patients implanted with intracerebral electrodes performed reaching movements while experiencing occasional unexpected force perturbations allowing study of the fronto-parietal, limbic and hippocampal network at unprecedented high spatial, and temporal scales. Areas including orbitofrontal cortex (OFC) and hippocampus showed increased activation during perturbed trials. These results, coupled with a visual novelty control task, suggest the hippocampal MTL-P300 novelty response is modality independent, and that the OFC is involved in modifying motor plans during robust movement.

The Stereo-Electroencephalography Methodology.

The stereo-electroencephalography (SEEG) methodology and technique was developed almost 60 years ago in Europe. The efficacy and safety of SEEG has been proven. The main advantage is the possibility to study the epileptogenic neuronal network in its dynamic and 3-dimensional aspect, with optimal time and space correlation, with the clinical semiology of the patient's seizures. The main clinical challenge for the near future remains in the further refinement of specific selection criteria for the different methods of invasive monitoring, with the ultimate goal of comparing and validating the results (long-term seizure-free outcome) obtained from different methods of invasive monitoring.

Lucky Rhythms in Orbitofrontal Cortex Bias Gambling Decisions in Humans.

It is well established that emotions influence our decisions, yet the neural basis of this biasing effect is not well understood. Here we directly recorded local field potentials from the OrbitoFrontal Cortex (OFC) in five human subjects performing a financial decision-making task. We observed a striking increase in gamma-band (36-50 Hz) oscillatory activity that reflected subjects' decisions to make riskier choices. Additionally, these gamma rhythms were linked back to mismatched expectations or "luck" occurring in past trials. Specifically, when a subject expected to win but lost, the trial was defined as "unlucky" and when the subject expected to lose but won, the trial was defined as "lucky". Finally, a fading memory model of luck correlated to an objective measure of emotion, heart rate variability. Our findings suggest OFC may play a pivotal role in processing a subject's internal (emotional) state during financial decision-making, a particularly interesting result in light of the more recent "cognitive map" theory of OFC function.

Avoiding early complications and reoperation during occipitocervical fusion in pediatric patients.

OBJECT: Surgical arthrodesis for pediatric occipitocervical (OC) instability has a high rate of success in a wide variety of challenging circumstances; however, identifying potential risk factors can help to target variables that should be the focus of improvement. The aim of this paper was to examine risk factors predictive of failure in a population of patients who underwent instrumented OC arthrodesis using a uniform surgical philosophy. METHODS: The authors conducted a retrospective cohort study of pediatric patients who underwent OC fusion from 2001 to 2013 at a single institution to determine risk factors for surgical failure, defined as reoperation for revision of the arthrodesis or instrumentation. The primary study outcome was either radiographic confirmation of successful OC fusion or surgical failure requiring revision of the arthrodesis or instrumentation. The secondary outcome was the underlying cause of failure (hardware failure, graft failure, or infection). Univariate analysis was performed to assess the association between outcome and patient demographics, cause of OC instability, type of OC instrumentation, bone graft material, biological adjuncts, and complications. RESULTS: Of the 127 procedures included, 20 (15.7%) involved some form of surgical failure and required revision surgery. Univariate analysis revealed that patients with deep wound infections requiring debridement were more likely to require surgical revision of the hardware or graft (p = 0.002). Subgroup analysis revealed that patients with skeletal dysplasia or congenital spinal anomalies were more likely to develop hardware failure than patients with other causes of OC instability (p = 0.020). Surgical failure was not associated with the method of C-2 fixation, type of rigid OC instrumentation, bone graft material, use of bone morphogenetic protein or biological adjuncts, cause of instability, sex, age, or having previous OC fusion operations. CONCLUSIONS: Pediatric patients in the present cohort with postoperative wound infections requiring surgical debridement had higher surgical failure rates after OC fusion. Those with skeletal dysplasia and congenital spinal anomalies were more likely to require reoperation for hardware failure. Better understanding of the mode of surgical failure may enable surgeons to develop strategies to decrease the need for reoperation in pediatric patients with OC instability.