Mohit Agrawal

Acute Foramen Magnum Syndrome Following Single Diagnostic Lumbar Puncture: Consequence of a Small Posterior Fossa?

BACKGROUND Type I Chiari malformation (CMI) is a rare complication of lumbar cerebrospinal fluid (CSF) drainage that is usually reported after lumbar drain or lumboperitoneal shunt placement. It usually remains asymptomatic; however, even if it becomes symptomatic, symptoms are usually mild. There are only a few reports of acute foramen magnum syndrome following continuous lumbar CSF drainage, and acute foramen magnum syndrome after a single diagnostic lumbar puncture (LP) has not been previously reported. We encountered this catastrophic complication in one of our patient. CASE DESCRIPTION A 30-year-old woman with a large supratentorial meningioma and associated asymptomatic CMI presented with holocranial headache. She underwent successful and uneventful excision of the tumor. However, she developed quadriplegia and respiratory arrest 48 hours following a diagnostic LP performed on postoperative day 9. She underwent urgent posterior fossa decompression after magnetic resonance imaging showed increased tonsillar impaction and swelling along with cervicomedullary compression. Postoperatively, she steadily improved and regained normal power after 3 months. Retrospective quantitative analysis of magnetic resonance imaging (MRI) revealed a small posterior fossa. CONCLUSIONS The association of intracranial tumors and lumbar CSF drainage with CMI is uncommon. The documentation of a small posterior fossa signifies the importance of both developmental (small posterior fossa) and acquired (intracranial tumor/lumbar CSF drainage) factors in pathogenesis of CMI. Although the extreme rarity of acute deterioration following a single LP does not warrant LP to be contraindicated in such patients, documentation of resolution of CMI with postoperative MRI before performing lumbar CSF drainage (whether therapeutic or diagnostic), might be helpful in avoiding this rare complication.

Management of Pediatric Posttraumatic Thoracolumbar Vertebral Body Burst Fractures by Use of Single-Stage Posterior Transpedicular Approach

PURPOSE The posterior transpedicular approach (PTA) is a posterior approach that has the advantage of achieving circumferential arthrodesis by a single posterior-only approach. The purpose of this study was to analyze our experience with PTA in the management of pediatric traumatic thoracolumbar burst fractures (TTLBFs). METHODS Consecutive pediatric patients (age ≤18 years) with TTLBFs treated with PTA for 6 years were included in this retrospective study. Correction of kyphotic deformity and change in neurologic status were analyzed to assess outcome. The Cobb angle and American Spinal Injury Association (ASIA) grade were used for this purpose. RESULTS There were 6 male and 8 female patients. Five patients had complete injury (ASIA-A), and 9 had incomplete injury. The mean Thoracolumbar Injury Classification and Severity score was 6.71. The mean preoperative Cobb angle was 14.71° and improved to -3.35° postoperatively (mean kyphosis correction -18.05°). Two of the patients experienced iatrogenic nerve root injury. There was 1 postoperative mortality due to complications unrelated to the surgery. The mean Cobb angle was -0.07° at the 32.2-month follow-up visit. Six patients experienced cage subsidence, but none required revision surgery. Postoperatively, 11 (78.5%) patients showed neurologic improvement, and none experienced deterioration. The average ASIA score improved from 2.5 to 3.78. A fusion rate of 100% (n = 12) was observed at the last follow-up visit. CONCLUSIONS The present study demonstrates that PTA is a feasible approach in selected pediatric patients with unstable traumatic thoracolumbar burst fractures, with results comparable with those in the adult population. This study demonstrates in detail the procedure, along with the neurologic and radiologic outcomes of this approach in the pediatric population.

Unusual Clinical Presentation and Magnetic Resonance Imaging Findings in Supratentorial Epidermoid Cyst

Epidermoid cysts in the lateral temporal lobe presenting with seizures are rare accounting for <5% of all intracranial epidermoid cysts. Preoperative diagnosis can be further confounded by unusual imaging as presented in this case, thus leading to the wrong preoperative diagnosis of the case as a neoplastic pathology.

Proposal of a New Safety Margin for Placement of C2 Pedicle Screws on Computed Tomography Angiography

BACKGROUND Screw diameters currently available are based on the literature available. No data are available for the safety margin available for C2 pedicle screw placement. The objective of this study was to define the average pedicle size available for placing C2 pedicle screws and to quantify the safety margin available in case of lateral breach of screw. METHODS Computed tomography angiograms of 259 patients (161 men, 98 women) were analyzed to calculate the C2 pedicle width, the area of the transverse foramen (TF) and the vertebral artery (VA), and the occupation ratio (OR) of the VA within the TF. The VA was classified into groups based on its lie within the TF (anteromedial, anterolateral, posteromedial, posterolateral, central, ectatic). The distance which the pedicle screw can breach without encountering the VA was calculated (lateral pedicle to vertebral artery distance [LPVA]). The diameters of the VA and the TF were estimated, and their difference gives the safety margin in case of breach of the lateral cortex of the C2 pedicle. RESULTS The mean mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis, in women was 5.3 mm and in men it was 5.8 mm. This difference was statistically significant. In 53.9% (122/226) of patients, the VA was dominant on the left side. The overall mean OR at the C2 vertebral level was found to be 37.3%. The mean LPVA was 0.9 mm, and the average overall safety margin available was 2.5 mm (range, 0.4-5.3 mm). CONCLUSIONS This study describes the relationship of the VA in the C2 TF and the relative risk during pedicle screw fixation.

Pigmented Ganglioglioma of the Cerebellum: Case Report and Review

BACKGROUND Gangliogliomas (GGs) are rare intra-axial tumors. Cerebellar seizures caused by GGs have been described only rarely. Pigmented neural cell tumors are well described in the literature but are infrequent, especially when presenting as primary neuroepithelial tumors. Only 5 cases of pigmented GG have been reported previously, including 4 in the pediatric population. CASE DESCRIPTION A 17-year-old female presented to us with cerebellar seizures, which resolved after tumor excision. Histopathological examination revealed a pigmented GG. CONCLUSIONS We present the sixth documented case of a pigmented ganglioglioma, the first such case reported in cerebellar location, associated with a rare presentation of cerebellar seizures.

Letter to the Editor Regarding “Burr-Hole Drainage for Chronic Subdural Hematoma under Low-Dose Acetylsalicylic Acid: a Comparative Risk Analysis Study”

LETTER: This is in reference to the article “Burr-Hole Drainage for Chronic Subdural Hematoma Under Low-Dose Acetylsalicylic Acid: A Comparative Risk Analysis Study” by Kamenova et al. The authors compared the perioperative and postoperative bleeding and cardiovascular complication rates of patients undergoing burr-hole drainage for chronic subdural hematoma with and without discontinuation of low-dose acetylsalicylic acid (ASA). We would like to point out a few limitations of the study that we found on reading the article.