Bridging the gap between neuroimaging and neurosurgery: a case of epidural arteriovenous fistula with an intradural presentation. Illustrative case.

BACKGROUND: Epidural arteriovenous fistulas (eAVFs) are rare vascular malformations often mistaken for their intradural counterparts due to similar angiographic features. Differentiation between epidural and intradural vascular lesions is crucial as it impacts surgical planning and prognosis. Despite advancements in diagnostic imaging, these entities can be misinterpreted and challenge management. OBSERVATIONS: The authors report the case of a 68-year-old male suspected to have a type I dural arteriovenous fistula based on magnetic resonance angiography and angiographic evaluation. He presented with progressive myelopathy and multiple neurological symptoms exacerbated by recent trauma. A superselective angiogram of the right T10 segmental artery suggested an intradural arteriovenous fistula; however, intraoperatively, the lesion was epidural. The arterialized venous structures were obliterated, and the patient reported significant postoperative symptomatic improvement. LESSONS: This case highlights the critical importance of comprehensive imaging and cautious interpretation in the diagnosis of spinal vascular malformations. It also underscores the need for a multidisciplinary approach to ensure accurate diagnosis and effective treatment. Surgeons must be prepared for intraoperative findings that diverge from preoperative imaging to adapt surgical strategies accordingly. Furthermore, this case contributes to the evolving understanding of eAVFs, suggesting that revised imaging protocols may be required to better distinguish epidural from intradural vascular abnormalities. https://thejns.org/doi/10.3171/CASE24331.

SymTC: A symbiotic Transformer-CNN net for instance segmentation of lumbar spine MRI.

Intervertebral disc disease, a prevalent ailment, frequently leads to intermittent or persistent low back pain, and diagnosing and assessing of this disease rely on accurate measurement of vertebral bone and intervertebral disc geometries from lumbar MR images. Deep neural network (DNN) models may assist clinicians with more efficient image segmentation of individual instances (discs and vertebrae) of the lumbar spine in an automated way, which is termed as instance image segmentation. In this work, we proposed SymTC, an innovative lumbar spine MR image segmentation model that combines the strengths of Transformer and Convolutional Neural Network (CNN). Specifically, we designed a parallel dual-path architecture to merge CNN layers and Transformer layers, and we integrated a novel position embedding into the self-attention module of Transformer, enhancing the utilization of positional information for more accurate segmentation. To further improve model performance, we introduced a new data synthesis technique to create synthetic yet realistic MR image dataset, named SSMSpine, which is made publicly available. We evaluated our SymTC and the other 16 representative image segmentation models on our private in-house dataset and public SSMSpine dataset, using two metrics, Dice Similarity Coefficient and the 95th percentile Hausdorff Distance. The results indicate that SymTC surpasses the other 16 methods, achieving the highest dice score of 96.169 % for segmenting vertebral bones and intervertebral discs on the SSMSpine dataset. The SymTC code and SSMSpine dataset are publicly available at https://github.com/jiasongchen/SymTC.

Neurological Surgery Residency Programs in the United States: A National Cross-Sectional Survey.

BACKGROUND AND OBJECTIVES: The Accreditation Council for Graduate Medical Education has approved 117 neurological surgery residency programs which develop and educate neurosurgical trainees. We present the current landscape of neurosurgical training in the United States by examining multiple aspects of neurological surgery residencies in the 2022-2023 academic year and investigate the impact of program structure on resident academic productivity. METHODS: Demographic data were collected from publicly available websites and reports from the National Resident Match Program. A 34-question survey was circulated by e-mail to program directors to assess multiple features of neurological surgery residency programs, including curricular structure, fellowship availability, recent program changes, graduation requirements, and resources supporting career development. Mean resident productivity by program was collected from the literature. RESULTS: Across all 117 programs, there was a median of 2.0 (range 1.0-4.0) resident positions per year and 1.0 (range 0.0-2.0) research/elective years. Programs offered a median of 1.0 (range 0.0-7.0) Committee on Advanced Subspecialty Training-accredited fellowships, with endovascular fellowships being most frequently offered (53.8%). The survey response rate was 75/117 (64.1%). Of survey respondents, the median number of clinical sites was 3.0 (range 1.0-6.0). Almost half of programs surveyed (46.7%) reported funding mechanisms for residents, including R25, T32, and other in-house grants. Residents received a median academic stipend of $1000 (range $0-$10 000) per year. Nearly all programs (93.3%) supported wellness activities for residents, which most frequently occurred quarterly (46.7%). Annual academic stipend size was the only significant predictor of resident academic productivity (R 2 = 0.17, P = .002). CONCLUSION: Neurological surgery residency programs successfully train the next generation of neurosurgeons focusing on education, clinical training, case numbers, and milestones. These programs offer trainees the chance to tailor their career trajectories within residency, creating a rewarding and personalized experience that aligns with their career aspirations.

Robotic-assisted single-position lateral for multilevel circumferential lumbar interbody fusion: how I do it.

BACKGROUND: Lateral lumbar interbody fusion supplemented with insertion of pedicle screws is a surgical procedure that has gained popularity in the last years, becoming an important tool in the armamentarium of spine surgeons. In recent years, there is a trend to complete both procedures in a single position, thus avoiding flipping the patient prone to insert the pedicle screws. METHODS: We describe a step-by-step workflow of the robotic-assisted technique for multilevel lateral lumbar interbody fusion supplemented with posterior instrumentation. The surgical procedure is performed in a single lateral position. For access to L4-5 or L5-S1, an oblique abdominal incision is performed in the same position, and the desired disc space is approached through an oblique or anterior corridor in the retroperitoneal space. CONCLUSION: Robotic-assisted single-position lateral for multilevel circumferential lumbar interbody fusion is a safe and effective procedure in patients where lumbar stabilization is required. This technique provides patients with a faster recovery and low risk of complications.

Single-Position Lateral Approach for Revision Thoracolumbar Corpectomy With Delayed Ipsilateral Kidney Atrophy: Technical Note and Discussion of Complications.

Improvements in navigation technology have enabled surgeons to safely offer single-position fusion surgeries, demonstrating shorter operating times and reduced length of stay (LOS) as compared to traditional lateral and prone dual-position surgeries. However, no studies to date describe revision thoracolumbar corpectomy with simultaneous posterior rod removal and replacement in the lateral position. Furthermore, this is the first reported complication of delayed ipsilateral kidney atrophy following lateral lumbar surgery. A 56-year-old male patient with history of metastatic hepatocellular carcinoma and complex surgical history for a prior T12 pathologic fracture presented to the clinic for follow-up. Computed tomography (CT) demonstrated bilateral broken rods and subsidence of the T12 interbody cage, for which he underwent revision T12 corpectomy and posterior instrumentation revision via a single-position, left-sided lateral approach. Simultaneous exposure and removal of the broken rods enabled the placement of two short temporary rods between the T11-L1 screws posteriorly, allowing for rod distraction and the placement of the expandable corpectomy cage into the appropriate position. On follow-up cancer surveillance imaging, the left kidney became progressively atrophic within six months after surgery. According to a review of PubMed, Scopus, and Embase databases, we describe the first reported case of a single-position thoracolumbar revision corpectomy with simultaneous rod replacement. Of particular importance in this technique is the use of temporary rod placement for distraction across the index level to facilitate interbody cage placement. Furthermore, we discussed the first reported complication of delayed ipsilateral kidney atrophy following lateral lumbar fusion.

Hounsfield Unit as a Predictor of Adjacent-Level Disease in Lumbar Interbody Fusion Surgery.

BACKGROUND: Bone density has been associated with a successful fusion rate in spine surgery. Hounsfield units (HUs) have more recently been evaluated as an indirect representation of bone density. Low preoperative HUs may be an early indicator of global disease and chronic process and, therefore, indicative of the need for future reoperation. OBJECTIVE: To assess preoperative HUs and their association with future adjacent segment disease requiring surgical intervention through retrospective study. METHODS: Patients who underwent lumbar interbody fusion at a single institution between 2007 and 2016 were retrospectively reviewed. Hounsfield unit values were measured from preoperative computed tomography (CT) using sagittal images, encircling cancellous portion of the vertebral body. Patient charts were reviewed for follow-up data and adjacent-level disease development. RESULTS: A total of 793 patients (age: 56.1 ± 13.7 years, 54.4% female) were included in this study. Twenty-two patients required surgical intervention for adjacent segment disease. Patients who underwent lumbar interbody fusion and did not subsequently require surgical intervention for adjacent-level disease were found to have a higher mean preoperative HU than patients who did require reoperation (180.7 ± 70.0 vs 148.4 ± 8.1, P = .032). Preoperative CT HU was a significant independent predictor for the requirement of adjacent-level surgery after spinal arthrodesis (odds ratio = 0.891 [0.883-0.899], P = .029). CONCLUSION: Patients who underwent lumbar interbody fusion that did not require reoperation for adjacent-level degeneration were found to have a higher mean preoperative HU than patients who did require surgical intervention. Lower preoperative CT HU was a significant independent predictor for the requirement of adjacent-level surgery after spinal arthrodesis.

Defining the Time Benefit of Awake Versus General Anesthesia for Single-Level Lumbar Spine Surgery.

BACKGROUND: Awake anesthesia with monitored anesthesia care (MAC) might confer time benefits compared with traditional general anesthesia (GA) in the setting of single-level lumbar spine surgery. Therefore, we sought to define the quantitative time difference spent in the operating room between the MAC and GA approaches for single-level lumbar spine surgery. METHODS: A prospectively maintained database of the senior surgeon was reviewed for single-level lumbar spine surgeries from 2019 to 2020 performed with the patient under either GA or MAC. The patient demographics, clinical features, time in the operating room, and postoperative outcomes were all summarized and statistically compared. RESULTS: A total of 53 patients satisfied all the selection criteria, with 25 (47%) in the GA group and 28 (53%) in the MAC group. Overall, most patients were men, with a median age of 60 years. The 2 groups were statistically comparable with respect to the demographics and preoperative anesthesia parameters. The time from room arrival to sedation start (median time, 26 vs. 38 minutes; P < 0.01), sedation time (median time, 55 vs. 87 minutes; P < 0.01), and time from sedation end to room exit (median time, 4 vs. 13 minutes; P < 0.01) were all significantly shorter for the MAC group. Additionally, the estimated blood loss was less in the MAC group (P < 0.01). CONCLUSIONS: We found MAC to be a safe anesthesia option for use in single-level lumbar spine surgery, which led to statistically significant benefits regarding the time under sedation and time in the operating room compared with GA. Future studies are required to understand whether MAC will require other synergistic measures to generate observable change at a health systems level.

Augmented Reality in Spinal Surgery: Highlights From Augmented Reality Lectures at the Emerging Technologies Annual Meetings.

Introduction Augmented reality (AR) is an advanced technology and emerging field that has been adopted into spine surgery to enhance care and outcomes. AR superimposes a three-dimensional computer-generated image over the normal anatomy of interest in order to facilitate visualization of deep structures without the ability to directly see them. Objective To summarize the latest literature and highlight AR from the annual "Spinal Navigation, Emerging Technologies and Systems Integration" meeting lectures presented by the Seattle Science Foundation (SSF) on the development and use of augmented reality in spinal surgery.  Methods  We performed a comprehensive literature review from 2016 to 2020 on PubMed to correlate with lectures given at the annual "Emerging Technologies" conferences. After the exclusion of papers that concerned non-spine surgery specialties, a total of 54 papers concerning AR in spinal applications were found. The articles were then categorized by content and focus. Results The 54 papers were divided into six major focused topics: training, proof of concept, feasibility and usability, clinical evaluation, state of technology, and nonsurgical applications. The greatest number of papers were published during 2020. Each paper discussed varied topics such as patient rehabilitation, proof of concept, workflow, applications in neurological and orthopedic spine surgery, and outcomes data. Conclusions The recent literature and SSF lectures on AR provide a solid base and demonstrate the emergence of an advanced technology that offers a platform for an advantageous technique that is superior, in that it allows the operating surgeon to focus directly on the patient rather than a guidance screen.

Augmented reality head-mounted display-based incision planning in cranial neurosurgery: a prospective pilot study.

OBJECTIVE: Monitor and wand-based neuronavigation stations (MWBNSs) for frameless intraoperative neuronavigation are routinely used in cranial neurosurgery. However, they are temporally and spatially cumbersome; the OR must be arranged around the MWBNS, at least one hand must be used to manipulate the MWBNS wand (interrupting a bimanual surgical technique), and the surgical workflow is interrupted as the surgeon stops to "check the navigation" on a remote monitor. Thus, there is need for continuous, real-time, hands-free, neuronavigation solutions. Augmented reality (AR) is poised to streamline these issues. The authors present the first reported prospective pilot study investigating the feasibility of using the OpenSight application with an AR head-mounted display to map out the borders of tumors in patients undergoing elective craniotomy for tumor resection, and to compare the degree of correspondence with MWBNS tracing. METHODS: Eleven consecutive patients undergoing elective craniotomy for brain tumor resection were prospectively identified and underwent circumferential tumor border tracing at the time of incision planning by a surgeon wearing HoloLens AR glasses running the commercially available OpenSight application registered to the patient and preoperative MRI. Then, the same patient underwent circumferential tumor border tracing using the StealthStation S8 MWBNS. Postoperatively, both tumor border tracings were compared by two blinded board-certified neurosurgeons and rated as having an excellent, adequate, or poor correspondence degree based on a subjective sense of the overlap. Objective overlap area measurements were also determined. RESULTS: Eleven patients undergoing craniotomy were included in the study. Five patient procedures were rated as having an excellent correspondence degree, 5 had an adequate correspondence degree, and 1 had poor correspondence. Both raters agreed on the rating in all cases. AR tracing was possible in all cases. CONCLUSIONS: In this small pilot study, the authors found that AR was implementable in the workflow of a neurosurgery OR, and was a feasible method of preoperative tumor border identification for incision planning. Future studies are needed to identify strategies to improve and optimize AR accuracy.

Cervical Subarachnoid Drain for the Treatment of Cerebrospinal Fluid Leak: 2-Dimensional Operative Video.

Cerebrospinal fluid (CSF) leak is a common phenomenon encountered by the neurosurgeon. It is most commonly come across after a neurosurgical procedure, but it can be seen idiopathically. Treatment usually ranges from conservative management through cerebrospinal fluid diversion to direct surgical repair. Continuous CSF drainage provides a path for diversion and allowing the site of the dural injury to heal effectively.1 Cervical subarachnoid drain is a safe and effective alternative when lumbar access is contraindicated or not achievable.2 Here we present a case of a 22-yr-old female with progressive symptomatic positional headaches due to a CSF leak from a prior deformity surgery treated with a cervical subarachnoid drain after a failed attempt at a direct repair. This 2-dimensional video illustrates the technique used for the placement of a cervical subarachnoid drain for the treatment of symptomatic CSF leak. Patient consented to the procedure and for the publication of their image.

"Disruptive Technology" in Spine Surgery and Education: Virtual and Augmented Reality.

BACKGROUND: Technological advancements are the drivers of modern-day spine care. With the growing pressure to deliver faster and better care, surgical-assist technology is needed to harness computing power and enable the surgeon to improve outcomes. Virtual reality (VR) and augmented reality (AR) represent the pinnacle of emerging technology, not only to deliver higher quality education through simulated care, but also to provide valuable intraoperative information to assist in more efficient and more precise surgeries. OBJECTIVE: To describe how the disruptive technologies of VR and AR interface in spine surgery and education. METHODS: We review the relevance of VR and AR technologies in spine care, and describe the feasibility and limitations of the technologies. RESULTS: We discuss potential future applications, and provide a case study demonstrating the feasibility of a VR program for neurosurgical spine education. CONCLUSION: Initial experiences with VR and AR technologies demonstrate their applicability and ease of implementation. However, further prospective studies through multi-institutional and industry-academic partnerships are necessary to solidify the future of VR and AR in spine surgery education and clinical practice.

A single institution experience with proximal junctional kyphosis in the context of existing classification schemes - Systematic review.

BACKGROUND: Proximal junctional kyphosis is a kyphotic deformity following spine instrumentation, predominantly seen in scoliosis patients. There have been previous attempts to develop classification schema of PJK. We analyzed the factors contributing to PJK based upon our own clinical experience with the goal of developing a clinical guidance tool which took into account both etiology and mechanism of failure. METHODS: We performed a retrospective analysis of all re-operation thoracolumbar surgeries at a single institution over a 14-year period. Patients with PJK were identified and categorized based upon the etiology, mechanism of failure, and an indication of revision. Next, we conducted a systematic review on articles emphasizing a classification system for PJK. RESULTS: Fourteen PJK patients were identified out of 121 patients who required revision spine surgery. The average age was 64.9 ± 10.2 years, with 10 males (71%) and 4 females (29%). Three primary etiologies were identified: 6/14 (47%) overcorrection, 6/14 (47%) osteopenia, and 2/14 (14%) ligamentous disruption. The mechanism of failure was likewise divided into three categories: 9/14 (64%) compression fracture, 1/14 (7%) hardware failure, and 4/14 (29%) disc degeneration. The relationship between osteopenia and the development of a compression fracture leading to PJK was statistically significant (p = 0.031). CONCLUSION: There are multiple current classification systems for PJK. Our study findings were in line with previously published literature and suggest the need for a future classification system combining both etiology, mechanism of failure, and severity of disease.

Quantifying Bone Quality Using Computed Tomography Hounsfield Units in the Mid-sagittal View of the Lumbar Spine.

BACKGROUND: Computed tomography Hounsfield unit (HU) is an alternative tool to the dual energy x-ray absorptiometry scan T-score to quantify the bone quality. DEXA scan can overestimate the bone mineral density. We studied the correlation of the vertebral mid-axial and mid-sagittal HU to the T-score. METHODS: We retrospectively reviewed the electronic medical records of patients who underwent dual energy x-ray absorptiometry and computed tomography scans within 1 year. Age, sex, mid-axial and mid-sagittal HU, and T-score were collected and statistically analyzed. RESULTS: We identified 100 patients with computed tomography of the L1-L4. There were 80 female and 20 male patients. The average age was 60.25 years (±12.54 years). Nineteen patients were diagnosed with degenerative spine disease. There were 56 patients with a normal T-score, 33 with osteopenia, and 11 with osteoporosis. The average HU for the mid-sagittal view was 163 (±59) for L1, 159 (±62) for L2, 151 (±59) for L3, and 150 (±62) for L4. The mid-axial and mid-sagittal HU were positively correlated to the DEXA T-score (P < 0.001). The HU was 177 (95% CI: 160-194) for normal T-scores, 132 (120-143) for T-scores indicating osteopenia, and 106 (88-124) for T-scores indicating osteoporosis (P < 0.001). Post hoc analysis showed no difference between osteopenia and osteoporosis (P = 0.46). CONCLUSIONS: Mid-sagittal HU is positively correlated to the T-score, similar to the mid-axial HU. Therefore, it can be used to acquire a general overview of the bone quality before spinal instrumentation.

The Focused Neurosurgical Examination During Telehealth Visits: Guidelines During the COVID-19 Pandemic and Beyond.

OBJECTIVE:  To provide guidelines to healthcare workers for performing a focused neurological examination via telemedicine during the coronavirus disease-2019 (COVID-2019) pandemic. METHODS:  We reviewed our department's outpatient clinic visits after the implementation of a telemedicine protocol in response to the COVID-19 crisis. Crossover rates from telehealth to in-person visits were evaluated and guidelines for performing a telemedicine neurological exam were created based on the consensus of 16 neurosurgical attending providers over a four-month period. RESULTS:  From March 23, 2020 to July 20, 2020, some 2157 telehealth visits were performed in our department. Some 26 were converted to in-person visits by the provider request with the most cited reason for conversion being the need for a more detailed patient evaluation. Based on these experiences, we created a graphical tutorial to address the key components of the neurological exam with adaptations specific to the telehealth visit. CONCLUSIONS:  In response to the global coronavirus pandemic, telemedicine has become an integral part of neurosurgeons' daily practice. Telemedicine failures remain low but primarily occur due to a need for more comprehensive evaluations. We provide guidelines for the neurosurgical exam during telehealth visits in an effort to assuage some of these issues.

Differences Between Neurosurgical Subspecialties in Telehealth Adoption.

OBJECTIVE: The health care field has been faced with unprecedented challenges during the COVID 19 pandemic. One such challenge was the implementation of enhanced telehealth capabilities to ensure continuity of care. In this study, we aim to understand differences between subspecialties with regard to patient consent and satisfaction following telehealth implementation. METHODS: A retrospective review of the electronic medical record was performed from March 2 to May 8, 2020 to evaluate surgical consents before and after telehealth implementation. Press Ganey survey results were also obtained both pre- and posttelehealth implementation and compared. RESULTS: There was no significant difference in the percentage of new patients consented for surgery (after being seen via telehealth only) between the cranial and spine services. For procedures in which >10 patients were consented for surgery, the highest proportion of patients seen only via telehealth was for ventriculoperitoneal shunt placement/endoscopic third ventriculostomy for the cranial service, and lumbar laminectomy and microdiscectomy for the spine service. Additionally, the spine service experienced marked improvement in Press Ganey scores posttelehealth implementation with overall doctor ranking improving from the 29th to the 93rd percentile, and likelihood to recommend increasing from the 24th to the 94th percentile. CONCLUSIONS: There were clear trends with regard to which pathologies and procedures were most amenable to telehealth visits, which suggests a potential roadmap for future clinic planning. Additionally, the notable improvement in spine patient satisfaction following the implementation of a telehealth program suggests the need for long-term process changes.

Augmented Reality-assisted Pedicle Instrumentation: Versatility Across Major Instrumentation Sets.

STUDY DESIGN: Laboratory investigation with phantom spine models. OBJECTIVES: The aim of this study was to demonstrate the ability of Augmented Reality system to track instruments from different companies without major modifications. SUMMARY OF BACKGROUND DATA: Augmented Reality is an emergent technology with applications in industrial, military, gaming, and medical fields. AR applications in Spine surgery are actively being developed. Features of headpiece ergonomics, digital processing power, intuitive interface, and reliable accuracy are being optimized for successful adaptation of technology into the field. System versatility across various instrumentation sets is important for cost-effectiveness and efficiency in application. METHODS: In this project, five phantom spine models were instrumented L1-S1 with pedicle screws from five major companies. AR assistance was used for all. Each screwdriver was equipped with a generic 3D printed navigation marker for tracking. RESULTS: Every instrumentation set was successfully paired with AR navigation imaging. Sixty pedicle screws were inserted with an average time of 1.6 min/screw. There was an evidence of learning curve with fastest time achieved of 1 min/screw. All five systems had equivocal radiographic outcomes. There were two breached screws (3%). CONCLUSION: Any currently available instrumentation set can readily pair for tracking with Augmented Reality system. Active tracking of the drivers allowed for improved accuracy making AR system very attractive as an adjunct to the current instrumentation techniques. LEVEL OF EVIDENCE: 3.