Introducing a novel hybrid educational boot camp to augment medical student training in neurosurgery

OBJECTIVE

Neurosurgery subinternships are a critical portion of the medical student application to neurosurgery residency programs, allowing programs to assess the student's clinical knowledge, interpersonal skills, work ethic, and character. Despite how critical these auditions are, many students have a poor understanding of expectations prior to beginning these subinternships. Thomas Jefferson University hosted a combined in-person and virtual boot camp session open to all medical students interested in neurosurgery. The authors sought to determine the effectiveness of this inaugural course.

METHODS

A total of 304 registered participants were sent a survey assessing their attitudes toward neurosurgery subinternships, beliefs about their abilities, and their comfort with various neurosurgical skills. All participants were sent a postsession survey composed of the same questions. The mean scores for responses to pre- and postsession survey questions were recorded based on graduating year and by medical school type (US allopathic [US MD], US osteopathic [US DO], or foreign degree/international medical graduate [IMG]). Differences in means between pre- and postsession survey responses were analyzed using the Student t-test, and statistical significance was set at p < 0.05.

RESULTS

A total of 112 presession surveys and 64 postsession surveys were completed, yielding a presession survey response rate of 36.8% and a postsession survey response rate of 21.1%. Seventy-five percent of the postsession survey respondents attended virtually, and 25% were in-person. US MD, US DO, and IMG attendees demonstrated a significantly increased understanding of the expectations of a neurosurgery subintern (p < 0.001). All students had significantly increased confidence in their ability to succeed as subinterns (US MD students and IMGs p < 0.001, US DO students p < 0.05). Regarding procedural confidence, US MD students had increased confidence in craniotomies and cranial plating (p < 0.001). When comparing responses by graduation year, students in the classes of 2024 and 2025 (rising 4th-year and rising 3rd-year medical students, respectively) demonstrated significantly increased understanding of expectations and confidence in their ability to succeed (< 0.001). Seventy-five percent of our postsession survey respondents attended virtually, and 25% were in-person. The in-person cohort had greater improvements in comfort with procedures such as craniotomies, cranial plating, and extraventricular drain placement (in-person vs Zoom mean differences: craniotomies and cranial plating, -2.29, extraventricular drain placement, -2.31) (p < 0.05).

CONCLUSIONS

The boot camp successfully delineated the expectations of neurosurgery subinterns and enhanced the attendees' confidence in their abilities. The authors concluded that a hybrid virtual and in-person format is beneficial and feasible in increasing accessibility to information about neurosurgery subinternships.

Does Body Mass Index Influence Intraoperative Costs and Operative Times for Anterior Cervical Discectomy and Fusion? A Time-Driven Activity-Based Costing Analysis

OBJECTIVE

Spine surgeons are often unaware of drivers of cost variation for anterior cervical discectomy and fusion (ACDF). We used time-driven activity-based costing to assess the relationship between body mass index (BMI), total cost, and operating room (OR) times for ACDFs.

METHODS

Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments. Timestamps for all involved personnel and material resources were documented. Total intraoperative costs were estimated for all ACDFs from 2017 to 2022. All patients were categorized into distinct BMI-based cohorts. Linear regression models were performed to assess the relationship between BMI, total cost, and OR times.

RESULTS

A total of 959 patients underwent ACDFs between 2017 and 2022. The average age and BMI were 58.1 ± 11.2 years and 30.2 ± 6.4 kg/m2, respectively. The average total intraoperative cost per case was $7120 ± $2963. Multivariable regression analysis revealed that BMI was not significantly associated with total cost (P = 0.36), supply cost (P = 0.39), or personnel cost (P = 0.20). Higher BMI was significantly associated with increased time spent in the OR (P = 0.018); however, it was not a significant factor for the duration of surgery itself (P = 0.755). Rather, higher BMI was significantly associated with nonoperative OR time (P < 0.001).

CONCLUSIONS

Time-driven activity-based costing is a feasible and scalable methodology for understanding the true intraoperative costs of ACDF. Although higher BMI was not associated with increased total cost, it was associated with increased preparatory time in the OR.

Do Busier Surgeons Have Lower Intraoperative Costs? An Analysis of Anterior Cervical Discectomy and Fusion Using Time-Driven Activity-Based Costing

STUDY DESIGN

The present study is a single-center, retrospective cohort study of patients undergoing neurosurgical anterior cervical discectomy and fusion (ACDF).

OBJECTIVE

Our objective was to use time-driven activity-based costing (TDABC) methodology to determine whether surgeons' case volume influenced the true intraoperative costs of ACDFs performed at our institution.

SUMMARY OF BACKGROUND DATA

Successful participation in emerging reimbursement models, such as bundled payments, requires an understanding of true intraoperative costs, as well as the modifiable drivers of those costs. Certain surgeons may have cost profiles that are favorable for these "at-risk" reimbursement models, while other surgeons may not.

METHODS

Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments (business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented. All surgeons performing ACDFs at our primary and affiliated hospital sites from 2017 to 2022 were divided into four volume-based cohorts: 1-9 cases (n=10 surgeons, 38 cases), 10-29 cases (n=7 surgeons, 126 cases), 30-100 cases (n=3 surgeons, 234 cases), and > 100 cases (n=2 surgeons, 561 cases).

RESULTS

The average total intraoperative cost per case was $7,116 +/- $2,945. The major cost contributors were supply cost ($4,444, 62.5%) and personnel cost ($2,417, 34.0%). A generalized linear mixed model utilizing Poisson distribution was performed with the surgeon as a random effect. Surgeons performing 1-9 total cases, 10-29 cases, and 30-100 cases had increased total cost of surgery (P < 0.001; P < 0.001; and P<0.001, respectively) compared to high-volume surgeons (> 100 cases). Among all volume cohorts, high-volume surgeons also had the lowest mean supply cost, personnel cost, and operative times, while the opposite was true for the lowest-volume surgeons (1-9 cases).

CONCLUSION

It is becoming increasingly important for hospitals to identify modifiable sources of variation in cost. We demonstrate a novel use of TDABC for this purpose.

LEVEL OF EVIDENCE

Level-III.

What is the Marginal Cost of Using Robot Assistance or Navigation for Transforaminal Lumbar Interbody Fusion? A Time-Driven Activity-Based Cost Analysis

BACKGROUND AND OBJECTIVE

Our primary objective was to compare the marginal intraoperative cost of 3 different methods for pedicle screw placement as part of transforaminal lumbar interbody fusions (TLIFs). Specifically, we used time-driven activity-based costing to compare costs between robot-assisted TLIF (RA-TLIF), TLIF with intraoperative navigation (ION-TLIF), and freehand (non-navigated, nonrobotic) TLIF.

METHODS

Total cost was divided into direct and indirect costs. We identified all instances of RA-TLIF (n = 20), ION-TLIF (n = 59), and freehand TLIF (n = 233) from 2020 to 2022 at our institution. Software was developed to automate the extraction of all intraoperatively used personnel and material resources from the electronic medical record. Total costs were determined through a combination of direct observation, electronic medical record extraction, and interdepartmental collaboration (business operations, sterile processing, pharmacy, and plant operation departments). Multivariable linear regression analysis was performed to compare costs between TLIF modalities, accounting for patient-specific factors as well as number of levels fused, surgeon, and hospital site.

RESULTS

The average total intraoperative cost per case for the RA-TLIF, ION-TLIF, and freehand TLIF cohorts was $24 838 ± $10 748, $15 991 ± $6254, and $14 498 ± $6580, respectively. Regression analysis revealed that RA-TLIF had significantly higher intraoperative cost compared with both ION-TLIF (β-coefficient: $7383 ± $1575, P < .001) and freehand TLIF (β-coefficient: $8182 ± $1523, P < .001). These cost differences were primarily driven by supply cost. However, there were no significant differences in intraoperative cost between ION-TLIF and freehand TLIF (P = .32).

CONCLUSION

We demonstrate a novel use of time-driven activity-based costing methodology to compare different modalities for executing the same type of lumbar fusion procedure. RA-TLIF entails significantly higher supply cost when compared with other modalities, which explains its association with higher total intraoperative cost. The use of ION, however, does not add extra expense compared with freehand TLIF when accounting for confounders. This might have implications as surgeons and hospitals move toward bundled payments.

Transforaminal Contrast Injection Before Computed Tomography-Guided Lateral Endoscopic Lumbar Diskectomy Improves Visualization of Exiting Nerve Root

BACKGROUND AND OBJECTIVES

Percutaneous endoscopic lumbar diskectomy (PELD) is an effective, minimally invasive method for removal of lateral lumbar disk herniations. This minimally invasive technique can be applied with high success and lead to faster recovery than traditional methods. Unfortunately, adoption of these techniques in the United States has been slow. A significant barrier to using this technique is often an inability to completely visualize relevant anatomy and increased operative times. In this article, we describe a technique using computed tomography (CT) guidance in conjunction with a neurogram to perform a PELD. We detail the steps in the technique and its advantages to the surgeon performing it.

METHODS

After a patient is placed supine on a table, a transforaminal injection of contrast is performed under fluoroscopic guidance. Then, after sterilizing and draping in a normal fashion, an intraoperative CT scan is taken with a reference frame in place. During the procedure, this allows for the CT guidance to have the exiting nerve root clearly outlined.

RESULTS

This procedure was successfully performed in a single patient, allowing greater visualization of the exiting nerve root during a difficult revision PELD case. No complications were experienced.

CONCLUSION

A novel technique using a neurogram with CT guidance during a PELD was used to assist with identification of anatomy and decompression of the exiting nerve root. This technique was used without complications.

What is the Marginal Intraoperative Cost of Using an Exoscope or Operative Microscope for Anterior Cervical Discectomy and Fusion? A Time-Driven Activity-Based Cost Analysis

OBJECTIVE

Our primary objective was to compare the intraoperative costs of 3 different surgical visualization techniques for anterior cervical discectomy and fusion (ACDF). Specifically, we used time-driven activity-based costing (TDABC) methodology to compare costs between ACDFs performed with operative microscopes (OM-ACDF), exoscopes (EX-ACDF), and loupes (loupes-ACDF).

METHODS

Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments (business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented. We identified all instances of loupes-ACDF (n = 882), EX-ACDF (n = 26), and OM-ACDF (n = 52) performed at our institution. We performed multivariable linear regression analyses to compare costs between these modalities, accounting for patient-specific factors as well as number of levels fused, surgeon, and hospital site.

RESULTS

The average total intraoperative costs per loupes-ACDF, EX-ACDF, and OM-ACDF cases were $7081 +/- $2,942, $7951 +/- $3,488, and $6557 +/- $954, respectively. Regression analysis revealed no difference in intraoperative cost between loupes-ACDF and EX-ACDF (P = 0.717), loupes-ACDF and OM-ACDF (0.954), or OM-ACDF and EX-ACDF (0.217). On a more granular level, however, EX-ACDF was associated with increased cost of consumables, including drapes, compared to both OM-ACDF (β-coefficient: $369 +/- $121, P = 0.002) and loupes-ACDF (β-coefficient: $284 +/- $86, P = 0.001).

CONCLUSIONS

Although hospitals may be aware of the purchasing fees associated with microscopes and exoscopes, there is no clear documentation of how these technologies affect intraoperative cost. We demonstrate a novel use of TDABC for this purpose.

Smartphone-based activity tracking for spine patients: Current technology and future opportunities

Activity trackers and wearables allow accurate determination of physical activity, basic vital parameters, and tracking of complex medical conditions. This review attempts to provide a roadmap for the development of these applications, outlining the basic tools available, how they can be combined, and what currently exists in the marketplace for spine patients. Various types of sensors currently exist to measure distinct aspects of user movement. These include the accelerometer, gyroscope, magnetometer, barometer, global positioning system (GPS), Bluetooth and Wi-Fi, and microphone. Integration of data from these sensors allows detailed tracking of location and vectors of motion, resulting in accurate mobility assessments. These assessments can have great value for a variety of healthcare specialties, but perhaps none more so than spine surgery. Patient-reported outcomes (PROMs) are subject to bias and are difficult to track frequently - a problem that is ripe for disruption with the continued development of mobility technology. Currently, multiple mobile applications exist as an extension of clinical care. These include Manage My Surgery (MMS), SOVINITY-e-Healthcare Services, eHealth System, Beiwe Smartphone Application, QS Access, 6WT, and the TUG app. These applications utilize sensor data to assess patient activity at baseline and postoperatively. The results are evaluated in conjunction with PROMs. However, these applications have not yet exploited the full potential of available sensors. There is a need to develop smartphone applications that can accurately track the functional status and activity of spine patients, allowing a more quantitative assessment of outcomes, in contrast to legacy PROMs.

When Does Intervention End and Surgery Begin? The Role of Interventional Pain Management in the Treatment of Spine Pathology

PURPOSE OF REVIEW

Recent advances in the field of interventional pain management (IPM) involve minimally invasive procedures such as percutaneous lumbar decompression, interspinous spacer placement, interspinous-interlaminar fusion and sacroiliac joint fusion. These developments have received pushback from surgical professional societies, who state spinal instrumentation and arthrodesis should only be performed by spine surgeons. The purpose of this review is to evaluate the validity of this claim. A literature search was conducted on Google Scholar and PubMed databases. Articles were included which examined IPM in the following contexts: credentialing and procedural privileging guidelines, fellowship training and education, and procedural outcomes compared to those of surgical specialties. Our primary research question is: "Should interventionalists be performing decompression and fusion procedures?".

FINDINGS

Advanced percutaneous spine procedures are not universally incorporated into pain fellowship curriculums. Trainees attempt to compensate for these deficiencies through industry-led training, which has been criticized for lacking central regulation. There is also a paucity of studies comparing procedural outcomes between surgeons and interventionalists for complex spine procedures, including decompression and fusion. Pain fellowship curriculums have not kept pace with some of procedural advancements within the field. Interventionalists are also not trained to manage potential complications of spinal instrumentation and arthrodesis, which has been recognized as an essential requirement for procedural privileging. Decompression and fusion may therefore be outside the scope of an interventionalist's practice.

A Multi-Disciplinary Review of Time-Driven Activity-Based Costing: Practical Considerations for Spine Surgery

STUDY DESIGN

A multi-disciplinary review.

OBJECTIVES

To provide a roadmap for implementing time-driven activity-based costing (TDABC) for spine surgery. This is achieved by organizing and scrutinizing publications in the spine, neurosurgical, and orthopedic literature which utilize TDABC and related methodologies.

METHODS

PubMed and Google Scholar were searched for relevant articles. The articles were selected by two independent researchers. After article selection, data was extracted and summarized into research domains. Preferred reporting items for systematic reviews and meta-analyses (PRISMA) systematic review process was followed.

RESULTS

Of the 524 articles screened, thirty-five articles met the inclusion criteria. Each included article was examined and reviewed to define the primary research question and objective. Comparing different procedures was the most common primary objective. Direct observation along with one other strategy (surveys, interviews, surgical database, or EMR) was most commonly employed during process map development. Across all surgical subspecialties (spine, neurologic, and orthopedic surgery), costs were divided into direct cost, indirect cost, cost to patient, and total costs. The most commonly calculated direct costs included personnel and supply costs. Facility costs, hospital overhead costs, and utilities were the most commonly calculated indirect costs. Transportation costs and parental lost wages were considered when calculating cost to patient. The total cost was a sum of direct costs, indirect costs, and costs to the patient.

CONCLUSION

TDABC provides a common platform to accurately estimate costs of care delivery. Institutions embarking on TDABC for spine surgery should consider the breadth of methodologies highlighted in this review to determine which type of calculations are appropriate for their practice.

Increased Surgeon-specific Experience and Volume is Correlated With Improved Clinical Outcomes in Lumbar Fusion Patients

STUDY DESIGN

The present study design was that of a single center, retrospective cohort study to evaluate the influence of surgeon-specific factors on patient functional outcomes at 6 months following lumbar fusion. Retrospective review of a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis identified the present study population.

OBJECTIVE

This study seeks to evaluate surgeon-specific variable effects on patient-reported outcomes such as Oswestry Disability Index (ODI) and the effect of North American Spine Society (NASS) concordance on outcomes in the setting of variable surgeon characteristics.

SUMMARY OF BACKGROUND DATA

Lumbar fusion is one of the fastest growing procedures performed in the United States. Although the impact of surgeon-specific factors on patient-reported outcomes has been contested, studies examining these effects are limited.

METHODS

This is a single center, retrospective cohort study analyzing a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis by 1 of 5 neurosurgery fellowship trained spine surgeons. The primary outcome was improvement of ODI at 6 months postoperative follow-up compared with preoperative ODI.

RESULTS

A total of 307 patients were identified for analysis. Overall, 62% of the study population achieved minimum clinically important difference (MCID) in ODI score at 6 months. Years in practice and volume of lumbar fusions were statistically significant independent predictors of MCID ODI on multivariable logistic regression ( P =0.0340 and P =0.0343, respectively). Concordance with evidence-based criteria conferred a 3.16 (95% CI: 1.03, 9.65) times greater odds of achieving MCID.

CONCLUSION

This study demonstrates that traditional surgeon-specific variables predicting surgical morbidity such as experience and procedural volume are also predictors of achieving MCID 6 months postoperatively from lumbar fusion. Independent of surgeon factors, however, adhering to evidence-based guidelines can lead to improved outcomes.

Accuracy and efficiency using frameless transient fiducial registration in stereoelectroencephalography and deep brain stimulation

OBJECTIVE

Stereotactic surgical methods continue to advance technologically. Frameless transient fiducial registration (FTFR) systems have been developed and avoid the need to move or position a patient in a frame after already receiving registration imaging. One such system, Neurolocate, has recently become available as a robotic attachment for the Neuromate stereotactic robot. This study is the largest in the literature to evaluate the accuracy of frameless registration using Neurolocate versus frame-based registration (FBR) methods in both deep brain stimulation (DBS) and stereoelectroencephalography (SEEG). Additionally, the authors sought to reevaluate factors affecting accuracy in both procedures.

METHODS

This study was a retrospective chart and imaging review of 88 consecutive procedures (involving 621 electrodes) implanting either DBS or SEEG at the authors' institution over a 5-year period from March 2015 to March 2020. Registration duration, radial target entry point, and Euclidean target implantation accuracies, as well as factors affecting accuracy, were recorded for each patient.

RESULTS

SEEG procedures included 38 patients and 525 implanted electrodes (294 using FBR and 231 using FTFR). DBS procedures included 50 patients and 96 implanted electrodes (65 using FBR and 31 using FTFR). Overall, FTFR registration was significantly more accurate (median 0.1 mm, IQR 0-0.4 mm) compared with FBR (median 1.3 mm, IQR 0.9-1.5 mm; p = 0.04). Likewise, FTFR had a significantly shorter duration of registration (median 84 minutes, IQR 77.3-95.3 minutes) when compared with FBR (median 110.5 minutes, IQR 107.3-138 minutes; p = 0.02). No significant differences were found when examining the radial entry point and Euclidean target implantation errors of each method.

CONCLUSIONS

FTFR with the Neurolocate system represents a technique that may decrease operative time while maintaining the high accuracy previously demonstrated by other stereotactic methods, despite an initial surgeon learning curve. It should be investigated in future studies to continue to improve stereotactic accuracies in neurosurgery.

Clinical outcomes in revision lumbar spine fusions: an observational cohort study

OBJECTIVE

The authors compared primary lumbar spine fusions with revision fusions by using patient Oswestry Disability Index (ODI) scores to evaluate the impact of the North American Spine Society (NASS) evidence-based medicine (EBM) lumbar fusion indications on patient-reported outcome measures of revision surgeries.

METHODS

This study was a retrospective analysis of a prospective observational cohort of patients who underwent elective lumbar fusion between January 2018 and December 2019 at a single quaternary spine surgery service and had a minimum of 6 months of follow-up. A prospective quality improvement database was constructed that included the data from all elective lumbar spine surgeries, which were categorized prospectively as primary or revision surgeries and EBM-concordant or EBM-discordant revision surgeries based on the NASS coverage EBM policy. In total, 309 patients who met the inclusion criteria were included in the study. The ODIs of all groups (primary, revision, revision EBM concordant, and revision EBM discordant) were statistically compared. Differences in frequencies between cohorts were evaluated using chi-square and Fisher's exact tests. The unpaired 2-tailed Student t-test and the Mann-Whitney U-test for nonparametric data were used to compare continuous variables. Logistic regression was performed to determine the associations between independent variables (surgery status and NASS criteria indications) and functional outcomes.

RESULTS

Primary lumbar fusions were significantly associated with improved functional outcomes compared with revisions, as evidenced by ODI scores (OR 1.85, 95% CI 1.16-2.95 to achieve a minimal clinically important difference, p = 0.01). The percentage of patients whose functional status had declined at the 6-month postoperative evaluation was significantly higher in patients who had undergone a revision surgery than in those who underwent a primary surgery (23% vs 12.3%, respectively). An increase in ODI score, indicating worse clinical outcome after surgery, was greater in patients who underwent revision procedures (OR 2.14, 95% CI 1.17-3.91, p = 0.0014). Patients who underwent EBM-concordant revision surgery had significantly improved mean ODI scores compared with those who underwent EBM-discordant revision surgery (7.02 ± 5.57 vs -4.6 ± 6.54, p < 0.01).

CONCLUSIONS

The results of this prospective quality improvement program investigation illustrate that outcomes of primary lumbar fusions were superior to outcomes of revisions. However, revision procedures that met EBM guidelines were associated with greater improvements in ODI scores, which indicates that the use of defined EBM guideline criteria for reoperation can improve clinical outcomes of revision lumbar fusions.

Achieving Value in Spine Surgery: 10 Major Cost Contributors

STUDY DESIGN

Narrative Review.

OBJECTIVES

The increasing cost of healthcare overall and for spine surgery, coupled with the growing burden of spine-related disease and rising demand have necessitated a shift in practice standards with a new emphasis on value-based care. Despite multiple attempts to reconcile the discrepancy between national recommendations for appropriate use and the patterns of use employed in clinical practice, resources continue to be overused-often in the absence of any demonstrable clinical benefit. The following discussion illustrates 10 areas for further research and quality improvement.

METHODS

We present a narrative review of the literature regarding 10 features in spine surgery which are characterized by substantial disproportionate costs and minimal-if any-clear benefit. Discussion items were generated from a service-wide poll; topics mentioned with great frequency or emphasis were considered. Items are not listed in hierarchical order, nor is the list comprehensive.

RESULTS

We describe the cost and clinical data for the following 10 items: Over-referral, Over-imaging & Overdiagnosis; Advanced Imaging for Low Back Pain; Advanced imaging for C-Spine Clearance; Advanced Imaging for Other Spinal Trauma; Neuromonitoring for Cervical Spine; Neuromonitoring for Lumbar Spine/Single-Level Surgery; Bracing & Spinal Orthotics; Biologics; Robotic Assistance; Unnecessary perioperative testing.

CONCLUSIONS

In the pursuit of value in spine surgery we must define what quality is, and what costs we are willing to pay for each theoretical unit of quality. We illustrate 10 areas for future research and quality improvement initiatives, which are at present overpriced and underbeneficial.

Bundled Payment Models in Spine Surgery

STUDY DESIGN

The following is a narrative discussion of bundled payments in spine surgery.

OBJECTIVE

The cost of healthcare in the United States has continued to increase. To lower the cost of healthcare, reimbursement models are being investigated as potential cost saving interventions by driving incentives and quality improvement in fields such a spine surgery.

METHODS

Narrative overview of literature pertaining to bundled payments in spine surgery synthesizing findings from computerized databases and authoritative texts.

RESULTS

Spine surgery is challenging to define payment modes because of high cost variability and surgical decision-making nuances. While implementing bundled care payments in spine surgery, it is important to understand concepts such as value-based purchasing, episodes of care, prospective versus retrospective payment models, one versus two-sided risk, risk adjustment, and outlier protection. Strategies for implementation underscore the importance of risk stratification and modeling, adoption of evidence based clinical pathways, and data collection and dissemination. While bundled care models have been successfully implemented, challenges facing institutions adopting bundled care payment models include financial stressors during adoption of the model, distribution of risks, incentivization of treating only low risk patients, and nuanced variation in procedures leading to variation in costs.

CONCLUSION

An alternative for fee for service payments, bundled care payments may lead to higher cost savings and surgeon accountability in a patient's care.

Robot-Assisted Instrumented Fusion of a T8-9 Extension Distraction Fracture and Epidural Hematoma Evacuation: 2-Dimensional Operative Video

The utilization of robotics has been gaining increased popularity in spine surgery. It can be used to assist in pedicle screw insertion when anatomy is complex in deformity surgery, but is also helpful in degenerative spine as it can minimize tissue dissection and fluoroscopy use.1-6 We present an operative video that demonstrates the use of a robotic system (Globus Excelsius GPS, Audubon, Pennsylvania) for thoracic instrumentation in an unstable fracture. The patient we present is a 64-yr-old male who sustained a T8-9 distraction extension fracture after falling down a flight of stairs. His computed tomography (CT) scan showed ossification of the anterior longitudinal ligament making ankylosing spondylitis the likely underlying condition.7,8 His magnetic resonance imaging showed an epidural hematoma extending from T7 to T11. Due to the unstable nature of this fracture and the presence of the hematoma, informed consent was obtained and the patient underwent thoracic pedicle screw fixation from T7 to T11 and laminectomy for hematoma evacuation. A preoperative CT was done for screw trajectory planning. Paraspinal muscle dissection was limited to the hematoma level to allow for laminectomy and evacuation. After registration of the patient to the robotic system using C-arm fluoroscopy, pilot burr holes are drilled using a rigid robotic arm and with optical tracking in real time. This reduces the degrees of freedom and allows for higher precision of screw placement. To the authors' knowledge, this video is the first one to show the utilization of robotics for thoracic instrumentation in an acute fracture.

Status of SARS-CoV-2 in cerebrospinal fluid of patients with COVID-19 and stroke

BACKGROUND

Emergence of the novel corona virus (severe acute respiratory syndrome (SARS)-CoV-2) in December 2019 has led to the COVID-19 pandemic. The extent of COVID-19 involvement in the central nervous system is not well established, and the presence or the absence of SARS-CoV-2 particles in the cerebrospinal fluid (CSF) is a topic of debate.

CASE DESCRIPTION

We present two patients with COVID-19 and concurrent neurological symptoms. Our first patient is a 31-year-old man who had flu-like symptoms due to COVID-19 and later developed an acute-onset severe headache and loss of consciousness and was diagnosed with a Hunt and Hess grade 3 subarachnoid haemorrhage from a ruptured aneurysm. Our second patient is a 62-year-old woman who had an ischaemic stroke with massive haemorrhagic conversion requiring a decompressive hemicraniectomy. Both patients' CSF was repeatedly negative on real-time PCR analysis despite concurrent neurological disease.

CONCLUSION

Our report shows that patients' CSF may be devoid of viral particles even when they test positive for COVID-19 on a nasal swab. Whether SARS-CoV-2 is present in CSF may depend on the systemic disease severity and the degree of the virus' nervous tissue tropism and should be examined in future studies.

Effects of distance and transport method on intervention and mortality in aneurysmal subarachnoid hemorrhage

OBJECTIVE Most patients suffering from aneurysmal subarachnoid hemorrhage (aSAH) initially present to a hospital that lacks a neurosurgical unit. These patients require interhospital transfer (IHT) to tertiary facilities capable of multidisciplinary neurosurgical intervention. Yet, little is known about the effects of IHT on the outcomes of patients suffering from aSAH. In this study, the authors examined the effects of IHT and transport method on the timing of treatment, rebleed rates, and overall outcomes of patients who have experienced aSAH. METHODS A retrospective review of medical records identified all consecutive patients who presented with aSAH at an outside hospital and subsequently underwent IHT to a tertiary aneurysm care center and patients who initially presented directly to a tertiary aneurysm care facility between 2008 and 2015. Demographic, operative, radiological, hospital of initial evaluation, transfer method, and outcome data were retrospectively collected. RESULTS The authors identified 763 consecutive patients who were evaluated for aSAH at a tertiary aneurysm care facility either directly or following IHT. For patients who underwent IHT and after accounting for these patients' clinical variability and dichotomizing the patients into groups transferred less than 20 miles and more than 20 miles, the authors noted a significant increase in mortality rates: 7% (< 20 miles) and 18.8% (> 20 miles) (p = 0.004). The increased mortality rate was partially explained by an increased rate of initial presentation to an accredited stroke center in patients undergoing IHT of less than 20 miles (p = 0.000). The method of transport (ground or air ambulance) was found to have significant effect on the patients' outcomes as measured by the Glasgow Outcome Scale score (p = 0.021); patients who underwent ground transport demonstrated a higher likelihood of discharge to home (p = 0.004). The increased severity of presentation in the patient cohort undergoing IHT by air as defined by the Glasgow Coma Scale score, a need for an external ventricular drain, Hunt and Hess grade, and intubation status at presentation did not result in increased mortality when compared with the ground cohort (p = 0.074). In addition, there was an 8-hour increase in duration of time from admission to treatment for the air cohort as compared with the ground cohort (p = 0.054), indicating a potential for further improvement in the overall outcome of this patient group. CONCLUSIONS Aneurysmal SAH remains a challenging neurosurgical disease process requiring highly coordinated care in tertiary referral centers. In this study, the overall distance traveled and the transport method affected patient outcomes. The time from admission to treatment should continue to improve. Further analysis of IHT with a focus on patient monitoring and treatment during transport is warranted.

Visualization of gap junction mobility in living cells

In order to study the dynamics of gap junctions in living cells, a cDNA was expressed in hepatocellular carcinoma-derived PLC cells coding for chimerical polypeptide Cx.EGFP-1, which consists of rat connexin32 and enhanced green fluorescent protein (EGFP). Cx.EGFP-1 was integrated into gap junctions, and the emitted epifluorescence reliably reported the distribution of the chimera. Therefore, stably transfected PLC clone PCx-9 was used to examine the dynamic behavior of gap junctions by time-lapse fluorescence microscopy. The pleomorphic fluorescent junctional plaques were highly motile within the plasma membrane. They often fused with each other or segregated into smaller patches, and fluctuation of fluorescence was detected within individual gap junctions. Furthermore, the uptake of junctional fragments into the cytoplasm of live cells was documented as originating from dynamic invaginations that form long tubulovesicular structures that pinch off. Endocytosis and subsequent lysosomal degradation, however, appeared to contribute only a little to the rapid gap junction turnover (determined half-life of 3.3 h for Cx.EGFP-1), since most cytoplasmic Cx.EGFP-1 fluorescence did not colocalize with the endocytosed fluid phase marker horseradish peroxidase or the receptor-specific endocytotic ligand transferrin and since it was distinct from lysosomes. Disassembly of gap junctions was monitored in the presence of the translation-inhibitor cycloheximide and showed increased endocytosis and continuous reduction of junctional plaques. Highly motile cytoplasmic microvesicles, which were detectable as multiple, weakly fluorescent puncta in all movies, are proposed to contribute significantly to gap junction morphogenesis by the transport of small subunits between biosynthetic, degradative, and recycling compartments.

Co-localization of proenkephalin- and prodynorphin-derived opioid peptides in laminae IV/V spinal neurons revealed in arthritic rats

By the use of highly selective antisera and an immunohistochemical technique the possible coexistence of proenkephalin- (PRO-ENK)- and prodynorphin (PRO-DYN)-derived peptides was examined in 4- to 6-micron thick serial sections of the L4-L5 segments of the spinal cord of non-colchicine-treated polyarthritic rats. In control, non-colchicine treated animals, virtually no cell bodies stained for the PRO-ENK-derived peptides, heptapeptide (MRF) and octapeptide (MRGL), nor for the PRO-DYN-derived peptides, dynorphin A (DYN) and alpha-neoendorphin (NEO). In contrast, in polyarthritic rats, numerous large (15-30 micron) multipolar neurons could be visualized with each antiserum in laminae IV/V. Alternate staining of adjacent sections with either anti-MRF or anti-MRGL antisera, followed by either anti-DYN or anti-NEO antisera, revealed a clear coexistence of PRO-ENK and PRO-DYN peptides. It was possible to demonstrate co-localization of all 4 opioids in a single cell. It appeared that all cells staining for PRO-ENK peptides in laminae IV/V also stained for PRO-DYN peptides.