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 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.

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.

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.

Spine surgery is kyphosing to spine surgeon.

BACKGROUND: Spine surgery is a demanding surgical specialty which requires surgeons to operate for hours on end, often compromising good posture. Sustained poor posture in the operating room (OR) can be the source of many adverse health effects on spine surgeons. This study will analyze posture of a spine surgeon in different types of spine surgery cases. METHODS: Posture of a surgeon was measured using the UPRIGHT Posture Training Device. The device was worn by the surgeon in the OR through a wide variety of spine surgery cases. RESULTS: The percent time spent slouched while performing cervical, adult deformity, and lumbar spine surgeries is 39.9, 58.9, and 38.6, respectively. For all surgeries recorded, the percent time slouched is 41.6. The average procedure time was 145.3 min, with adult deformity cases on average being the longest (245.6 min) followed by cervical (152.9 min) and then lumbar (122.5 min). CONCLUSION: Poor posture while operating is very likely to occur for many spine surgeons regardless of case type. This poor posture is maintained for long periods of time given the average spine surgery procedure recorded in the study was roughly 2.5 h long. Spine surgeons should be aware of the tendency for poor posture while operating, and they should try using posture-improving techniques to maintain good spine health.

Vagus Nerve Stimulation in Rodent Models: An Overview of Technical Considerations.

Over the last several decades, vagus nerve stimulation (VNS) has evolved from a treatment for select neuropsychiatric disorders to one that holds promise in treating numerous inflammatory conditions. Growing interest has focused on the use of VNS for other indications, such as heart failure, rheumatoid arthritis, inflammatory bowel disease, ischemic stroke, and traumatic brain injury. As pre-clinical research often guides expansion into new clinical avenues, animal models of VNS have also increased in recent years. To advance this promising treatment, however, there are a number of experimental parameters that must be considered when planning a study, such as physiology of the vagus nerve, electrical stimulation parameters, electrode design, stimulation equipment, and microsurgical technique. In this review, we discuss these important considerations and how a combination of clinically relevant stimulation parameters can be used to achieve beneficial therapeutic results in pre-clinical studies of sub-acute to chronic VNS, and provide a practical guide for performing this work in rodent models. Finally, by integrating clinical and pre-clinical research, we present indeterminate issues as opportunities for future research.

Workflow Caveats in Augmented Reality-Assisted Pedicle Instrumentation: Cadaver Lab.

BACKGROUND: Augmented reality (AR) is gaining popularity in gaming, industrial, military, and medical fields. Neurosurgical applications are currently limited and underdeveloped. METHODS: The cadaver lab session was prepared with the currently available AR equipment and software. Pedicle instrumentation was performed from thoracic 1 to the pelvis with either fluoroscopy or AR. RESULTS: A total of 38 screws were placed. There were no major breaches on the fluoroscopy-assisted side. Among the AR screws, 3 had a major medial breach and 4 had a major inferior breach. The cause of a 3 breaches appeared to be related to an error in the starting position, as their overall orientation remained correctly parallel to the original trajectory. CONCLUSIONS: The article discusses the potential and limitations of AR in its current state and identifies strategies for successful AR application in future surgery.

Epidemiology and etiology of secondary piriformis syndrome: A single-institution retrospective study.

Piriformis syndrome (PS) is a rare etiology of extra-spinal sciatica in which pathologies associated with or around the piriformis muscle (PM) irritate the adjacent sciatic nerve (SN), however, there is scarcity in the literature regarding its exact etiologies, thus, we performed a retrospective study to elucidate the epidemiology of PS and assess various causes of the syndrome. Our study included patients assessed at our institution who presented with sciatica of non-spinal origin between May 2014 and December 2015. Radiology reports of all patients who received pelvic MRI were examined for positive findings involving PM and SN. Of the 143 patients recognized with sciatica and negative lumbar pathology, 24 patients (17%) exhibited positive PM and SN findings. Average patient age was 50.0 ±â€¯15.1 years (range: 21-75), and 17 were female. Seven patients (5%; 4M/3F) presented with tumor, seven patients (5%) had chronic inflammatory changes, one patient had SN adhesions to obturator muscle, three patients (2%, 3F) had aberrant anatomy, and the remaining patients had positive MRI findings, such as nerve atrophy or PM hypertrophy without identifiable cause. Seven patients received steroid injections in the peri-sciatic fossa, and four displayed poor response. Our findings suggested possible trends in extra-spinal sciatica. Affected males appeared more likely to present with tumor, while affected females were more likely to present younger, but with aberrant anatomy. Steroid injections appeared to be suboptimal in most cases. Pelvic MRI is helpful in patients with sciatica and negative spine imaging to rule out neoplastic involvement.

Practical Assessment of Radiation Exposure in Spine Surgery.

BACKGROUND: Fluoroscopy use in spine surgery is increasing owing to the increasing popularity of minimally invasive techniques. The effectiveness and safe distance for protective barriers might have been commonly misrepresented. The present study evaluated x-ray propagation and the efficacy of protective barriers in the setting of spine surgery. METHODS: A high-accuracy radiation dosimeter was used to measure x-ray exposure in an experimental setting replicating the spine surgery setup. Radiation was measured at different angles and distances from the x-ray source with and without protective barriers such as lead gowns and glass. RESULTS: The radiation values return to baseline at 14 ft (4.3 m) in front of the x-ray source and 8 ft (2.4 m) behind it. Protective barriers with a 0.5-mm lead-equivalence reduced radiation exposure to baseline at 6 ft (1.8 m) and were 20% effective at 2 ft (0.6 m) from the emitter. CONCLUSION: Spine surgeons who wear lead gowns during fluoroscopy could still be exposed to <80% of the radiation produced. Safe distances from fluoroscopy machines might be much farther than commonly believed. Alternatives to reduce the use of fluoroscopy for intraoperative imaging should be explored.

Repair of giant postlaminectomy pseudomeningocele with fast-resorbing polymer mesh: technical report of 2 cases.

Pseudomeningocele is a rare but well-known complication of lumbar spine surgery, which arises in 0.068%-0.1% of individuals in large series of patients undergoing laminectomy and in up to 2% of patients with postlaminectomy symptoms. In symptomatic pseudomeningoceles, surgical reexploration and repair of the dural defect are typically necessary. Whereas the goals of pseudomeningocele repair, which are extirpation of the pseudomeningocele cavity and elimination of extradural dead space, can typically be achieved by primary closure performed using nonabsorbable sutures, giant pseudomeningoceles (> 8 cm) can require more elaborate repair in which fibrin glues, dural substitute, myofascial flaps, or all of the above are used. The authors present 2 cases of postsurgical symptomatic giant pseudomeningoceles that were repaired using a fast-resorbing polymer mesh-supported reconstruction technique, which is described here for the first time.

Vertebral Artery Dissection in a Bouncy Castle Injury: Case Report and Literature Review.

There is an increased rate of injuries associated with activities on bouncy castles. The purpose of this article was to describe the case of a 6-year-old boy who sustained a brain infarct as a consequence of a left posterior inferior cerebellar artery dissection due to improper landing in a bouncy castle and who required a suboccipital craniotomy. The second goal was to outline the literature review regarding cervical trauma related to trampoline or bouncy castle accidents in pediatric populations. Based on the described case and reviewed studies, bouncy castle or any other activity resulting in hyperflexion or hyperextension of the neck should be carefully evaluated for cervical spine fractures and vascular injuries.

Initial academic experience and learning curve with robotic spine instrumentation.

OBJECTIVE Spine surgery is complex and involves various steps. Current robotic technology is mostly aimed at assisting with pedicle screw insertion. This report evaluates the feasibility of robot-assisted pedicle instrumentation in an academic environment with the involvement of residents and fellows. METHODS The Renaissance Guidance System was used to plan and execute pedicle screw placement in open and percutaneous consecutive cases performed in the period of December 2015 to December 2016. The database was reviewed to assess the usability of the robot by neurosurgical trainees. Outcome measures included time per screw, fluoroscopy time, breached screws, and other complications. Screw placement was assessed in patients with postoperative CT studies. The speed of screw placement and fluoroscopy time were collected at the time of surgery by personnel affiliated with the robot's manufacturer. Complication and imaging data were reviewed retrospectively. RESULTS A total of 306 pedicle screws were inserted in 30 patients with robot guidance. The average time for junior residents was 4.4 min/screw and for senior residents and fellows, 4.02 min/screw (p = 0.61). Among the residents dedicated to spine surgery, the average speed was 3.84 min/screw, while nondedicated residents took 4.5 min/screw (p = 0.41). Evaluation of breached screws revealed some of the pitfalls in using the robot. CONCLUSIONS No significant difference regarding the speed of pedicle instrumentation was detected between the operators' years of experience or dedication to spine surgery, although more participants are required to investigate this completely. On the other hand, there was a trend toward improved efficiency with more cases performed. To the authors' knowledge, this is the first reported academic experience with robot-assisted spine instrumentation.

Management of Foramen Magnum Meningioma During Pregnancy: Literature Review and Case Report.

BACKGROUND: Foramen magnum meningiomas are very rare and challenging lesions. Their presentation in women during pregnancy tremendously complicates the course of gestation. Conservative management is always the first option, but in cases of a deteriorating clinical picture, there are currently no clear guidelines on best management. CASE DESCRIPTION: A woman presents in the 30th week of pregnancy with pain and progressive numbness in right posterior aspect of neck and right arm. Foramen magnum meningioma was diagnosed and successful surgical resection was performed with intraoperative fetal hearth monitoring and three fourths prone position of the patient. CONCLUSIONS: We believe a three fourths prone position of a pregnant patient is safe and adequate for the far-lateral exposure of craniocervical lesions. Rapid growing of tumor can be precipitated by steroids management during pregnancy.

Percutaneous Drainage of Chronic Destructive Lumbar Osteomyelitis Abscess Via the Use of Bilateral Transpedicular Trocar Access.

BACKGROUND: Pyogenic spondylodiskitis is an infection of intervertebral disks and spinal vertebral bodies. Various minimally invasive approaches to the infected disk spaces/abscesses have been described for management of early stages of the infection. Patients with chronic occurrence present with extensive infection, neurologic deficits, and bone destruction. Such patients commonly have substantial medical comorbidities. Despite the increased risks of complications, they often are treated with open surgical approaches without minimally invasive options. We describe a bilateral transpedicular approach to vertebral body abscess in a chronically infected patient with intraoperative contiguous irrigation. CASE DESCRIPTION: We present 2 cases, a 58-year-old man and a 61-year-old man, both with a diagnosis of vertebral osteomyelitis. Images of lumbar spine showed epidural abscess and adjacent vertebral body destruction. Because of their poor clinical condition and chronicity of disease, these patients underwent percutaneous bilateral transpedicular approach. CONCLUSION: Patients in poor health and with chronic vertebral osteomyelitis may benefit from minimally invasive percutaneous transpedicular drainage and irrigation of the abscess, representing a minimally invasive and effective treatment alternative for these patients.

Atlantoaxial Synovial Cyst: Case Report and Literature Review.

BACKGROUND: Degenerative cystic lesions of atlantoaxial joints are rare and generally believed to be due to mechanical instability. There is currently no consensus on the management of such lesions in symptomatic and asymptomatic patients. Both conservative and surgical strategies have been described. Surgery may involve anterior or posterior approaches with and without decompression and instrumentation. METHODS: We present a case report of a 45-year-old man who presented with new onset weakness and ataxia. Physical examination revealed decreased motor function in all extremities as well as positive Hoffman sign and ankle clonus bilaterally. An MRI of cervical spine showed a large atlantoaxial, T-2 hyperintense cystic lesion with cord compression and cord signal changes. RESULTS: A C1 partial laminectomy was performed with resection of the cyst and C1-2 instrument fusion. Intra-operatively, the cystic lesion was found to be anatomically connected to the right C1-2 atlantoaxial joint with pathology showing fibroconnective tissue and chronic inflammatory changes. Post-operatively there were no complications and the patient was discharged to a rehabilitation facility. The patient was regaining gait and hand function by 3 months after surgery. CONCLUSIONS: Atlantoaxial synovial cysts are rare and the optimal surgical approach has not been determined. We further conducted a literature review and found a total of 70 other cases of atlantoaxial synovial cysts reported to date in the literature. We attempt to analyze available data and evaluate anterior versus posterior approaches and the need for decompression, amount of cyst resection, and instrumentation.