Morphometric analysis of atlas lateral mass in Down syndrome cases with relevance to surgical intervention.

PURPOSE: Surgical stabilization of the Atlas vertebrae is indicated for severe atlantoaxial instability (AAI) in patients with Down syndrome (DS). This study aims to evaluate the morphological characteristics of the Atlas lateral mass (ALM) in patients with DS with regard to safe instrumentation for surgical stabilization and to compare them with non-syndromic group. METHODS: This multicenter, retrospective, case-control study included age- and sex-matched patients with and without DS aged > 7 years with a cervical computed tomography (CT) scan. After three-dimensional CT reconstruction, nine parameters were evaluated for both groups. All included measurements were performed by a neuroradiologist who was blinded to clinical data. RESULTS: Forty-three of 3,275 patients with DS were included in this study. Matching number of consecutive patients without DS were identified (mean age: 16 years). Patients with DS were significantly shorter than those without DS. Seven of nine parameters related to ALM were significantly lower in patients with DS than in those in the control group, including anterior wall height (AH), posterior wall height (PH), their ratio, and arch-ALM angle. On adjusting data for patient height, patients with DS had a smaller PH, lower PH/AH ratio, and steeper arch-ALM angle than the control group. CONCLUSIONS: Patients with DS had a smaller posterior ALM wall and a steeper arch-ALM angle than the control group without DS. This information is important for surgical planning of safe posterior ALM exposure and safe instrumentation for surgical stabilization in patients with DS.

Association between craniovertebral junction abnormalities and syringomyelia in patients with chiari malformation type-1.

OBJECTIVE: To assess the correlation between craniovertebral junction (CVJ) abnormalities and syringomyelia in patients with Chiari malformation type-1 (CM1). METHODS: This was a retrospective study including patients with CM1. Identification of cases was done by searching a radiology database at a university hospital from 2012 to 2017. Patients were divided into 2 groups based on whether CVJ abnormalities were present (CVJ+) or absent (CVJ-). The patients` demographic and clinical data were reviewed. All magnetic resonance imaging studies were examined by a certified neuroradiologist. RESULTS: Sixty-four consecutive patients with CM1 were included. The mean age was 24+/-17 years; 59% were females. The CVJ+ group had more female patients (p=0.012). The most frequent CVJ abnormality was platybasia (71%), followed by short clivus (44%) and cervical kyphosis (33%). The CVJ abnormalities were more in Syringomyelia cases (p=0.045). However, the results were not significant when hydrocephalus cases were excluded. CONCLUSION: Among CM1 patients, CVJ abnormalities were found more in patients with syringomyelia. Future studies with larger sample size are required to further study the correlation between CVJ abnormalities and both syringomyelia and hydrocephalus in CM1 patients.

Length of MRI signal may predict outcome in advanced cervical spondylotic myelopathy.

OBJECTIVE: To study clinical and radiological factors that may correlate with independent walking (IW) following advanced cervical spondylotic myelopathy (CSM) surgery. METHODS: A retrospective case series including all advanced CSM patients (Nurick 4 and 5) who underwent surgery from 2003-2010 in the Division of Neurosurgery, Department of Surgery, College of Medicine, King Saud University and King Khalid University Hospital, Riyadh, Saudi Arabia. Only patients with 6 months or more follow-up were included. A neuroradiologist who was blinded to the clinical data reviewed all MRI studies. RESULTS: Forty-three patients were included (83% males, mean follow-up 29 months). A better preoperative neurological status was a positive predictor of IW after surgery (85.7% Nurick 4 versus 36.4% Nurick 5, p=0.001). Independent walking was less likely in patients with the following MRI features: longer T2-weighted image (T2WI) signal changes (p=0.001), well-circumscribed T2WI signal changes (p=0.028), T1WI hypointensity (p=0.001), and narrow spinal canal diameter (p=0.048). Multivariate regression revealed that both an increased T2WI signal change length and T1WI hypointensity were independent predictors. The risk of dependent walking increased by 1.35 times as the T2WI signal intensity length increased by one mm, and by 14-times with T1WI hypointensity. CONCLUSION: Regaining IW after surgery in patients with advanced CSM was less likely for cases showing MRI features of longer T2WI signal changes and T1WI hypointensity. Better baseline walking, less defined T2WI signal change, and a wider spinal canal were good prognostic factors.

Perception of Neurosurgery Residents and Attendings on Online Webinars During COVID-19 Pandemic and Implications on Future Education.

BACKGROUND: Online education has provided an important tool to continue medical education during the COVID-19 pandemic. Our study aimed to evaluate trainee and attending perceptions of online webinars as an educational tool in neurosurgery. METHODS: We conducted a cross-sectional survey study. A web-based 19-question survey was distributed to the people who attended the webinar series that was carried out by the Saudi Association of Neurological Surgery from March 29, 2020 to May 31, 2020. Candidates were identified through their registration e-mails. The survey was distributed June 5-8, 2020. RESULTS: A total of 156 responses were received (survey response rate: 60%). The overall satisfaction rate among residents and attendings (board-certified neurosurgeons) was similar (>80%). However, only 56.4% of attendings reported they were comfortable with online webinars compared with 81.2% of residents (P value <0.0001). Seventy-five percent of residents found online lectures more useful than traditional in-person lectures compared with 52% of attendings (P value = 0.01). CONCLUSIONS: Online educational webinars provide an educational value that can be considered as an adjunct to traditional (in-person) education methods. Among trainees, the satisfaction of neurosurgery webinars was encouraging to consider as an education method. More objective research and progress are required to adopt and refine existing online didactic and neurosurgical teaching tools while creating more engaging future distant learning models.

Atlas instrumentation guided by the medial edge of the posterior arch: An anatomic and radiologic study.

STUDY DESIGN: This was an interventional human cadaver study and radiological study. OBJECTIVES: Atlas instrumentation is frequently involved in fusion procedures involving the craniocervical junction area. Identification of the entry point at the center of atlas lateral mass (ALM) is challenging because of its rounded posterior surface and the surrounding venous plexus. This report examines using the medial edge of atlas posterior arch (MEC1) as a fixed and reliable anatomic reference to guide the entry point of ALM screws. METHODS: Fifty, normal, cervical spine computed tomography studies were reviewed. ALM screw trajectories were planned at one point along MEC1 and another point 2 mm lateral to MEC1. Free-hand ALM instrumentation was performed in ten fresh human cadavers using the 2 mm entry point, with a sagittal trajectory parallel to atlas inferior arch (IAC1); three-dimensional imaging was then performed to confirm instrumentation accuracy. RESULTS: The average ALM diameter was 12.35 mm. Inserting a screw using the entry point 2 mm lateral to MEC1 was closer to ALM midpoint than using the entry point along MEC1 (P < 0.0001). Twenty ALM screws were successfully inserted in the ten cadavers. No encroachments into the spinal canal or foramen transversarium occurred. However, two screws were superiorly directed and violated the occipitocervical joint; they were not parallel to IAC1. CONCLUSION: MEC1 provides a fixed and reliable landmark for ALM instrumentation. An entry point 2 mm point lateral to MEC1 is close to ALM midpoint. IAC1 also provides a guide for the sagittal trajectory. Attention to anatomic landmarks may help reduce complications associated with atlas instrumentation but should be verified in future clinical studies.

Segmental Surface Referencing during Intraoperative Three-dimensional Image-Guided Spine Navigation: An Early Validation with Comparison to Automated Referencing.

Study Design Interventional human cadaver study. Objective Intraoperative three-dimensional (3-D)-guided navigation improves spine instrumentation accuracy. However, image acquisition may need to be repeated with segment hypermobility or distant target from reference frame (RF). The current study evaluates the usefulness of internal metal fiducials (IMFs) as surface references in enhancing registration accuracy and avoiding repeating imaging. Methods Six fresh-frozen cadaveric human torsos were utilized. Posterior C1-T2 exposure was done, and three IMFs were inserted per level; intraoperative 3-D images were then acquired. Two registration methods were utilized: autoregistration (AR, group 1) and point registration using IMF (IMFR, group 2). Registration accuracy was checked by identifying IMFs in both groups. Pedicle screws inserted into C2, C4, C5, and C7 based on the two registration methods (three cadavers each) with RF on C7 and then on C2. Results The mean registration error was lower with IMFR compared with AR (0.35 ± 0.5 mm versus 2.02 ± 0.85 mm, p = 0.0001). Overall, 34 pedicle screws were inserted (AR, 18; IMFR, 16). Final screw placement was comparable using both techniques (p = 0.58). Lateral screws violations were observed in four IMFR screws (1 to 2 mm) as compared with five in AR group (2 to 3 mm). Reregistration after moving RF to C2 was possible using surface screws in IMFR group, thus avoiding new 3-D image acquisition. Conclusion During intraoperative 3-D navigation in spine procedures, surface fiducial registration using IMF provided superior accuracy over automated registration. It allowed repeat registration without repeating radiation during long spine segment instrumentations. More studies are needed to clarify both practical and clinical application of this method.

Computer-Assisted Navigation During an Anterior-Posterior En Bloc Resection of a Sacral Tumor.

Previously, a computer-based navigation system has not been used routinely for en-bloc resection of sacral tumors. In order to improve the accuracy of tumor resection, O-arm navigation was used to join anterior and posterior osteotomies during an en-bloc resection of a sacral Ewing's sarcoma. This case study describes the technique for en-bloc resection of a sacral Ewing's sarcoma guided by O-arm computer navigation and intraoperative neurophysiological monitoring (IONM). An 18-year-old male presented with weakness in his left lower extremity. MRI of the patient's spine showed a sacral mass causing compression of left S1 and S2 roots. A surgical resection was planned with anterior and posterior approaches. An O-arm computer navigation system was used to assist in meeting anterior osteotomy cuts with the posterior cuts to ensure complete resection of the sacral tumor with a safe margin. Computer-assisted navigation was used along with IONM during this procedure to help guide the surgical team in an adequate tumor resection. There were no complications related to the use of the O-arm or the navigation system. Computer navigation guidance is both useful and safe in sacral tumor resections. It enhanced the accuracy of the en-bloc removal of a sacral tumor with safe margins while protecting neural function and minimizing recurrence.

Clinical predictors of recovery after blunt spinal cord trauma: systematic review.

Several clinical, imaging, and therapeutic factors affecting recovery following spinal cord injury (SCI) have been described. A systematic review of the topic is still lacking. Our primary aim was to systematically review clinical factors that may predict neurological and functional recovery following blunt traumatic SCI in adults. Such work would help guide clinical care and direct future research. Both Medline and Embase (to April 2008) were searched using index terms for various forms of SCI, paraplegia, or quadri/tetraplegia, and functional and neurological recovery. The search was limited to published articles that were in English and included human subjects. Article selection included class I and II evidence, blunt traumatic SCI, injury level above L1-2, baseline assessment within 72 h of injury, use of American Spinal Injury Association (ASIA) scoring system for clinical assessment, and functional and neurological outcome. A total of 1526 and 1912 citations were located from Medline and Embase, respectively. Two surgeons reviewed the titles, abstracts, and full text articles for each database. Ten articles were identified, only one of which was level 1 evidence. Age and gender were identified as two patient-related predictors. While motor and functional recovery decreased with advancing age for complete SCI, there was no correlation considering incomplete ones. Therefore, treatment should not be restructured based on age in incomplete SCI. Among injury-related predictors, severity of SCI was the most significant. Complete injuries correlated with increased mortality and worse neurological and functional outcomes. Other predictors included SCI level, energy transmitted by the injury, and baseline electrophysiological testing.