July 2021
Two Bolt MRI Guided Laser Ablation for Seizure Focus in the Lateral Position Utilizing Robotic Bolt Implantation
Authors: Somnath Das, BS; Michael Kogan, MD; Ashwini Sharan, MD
Online Publication Date: Jan 2021
Epidemiology Approximately 7-10% of adolescent epilepsy patients will have drug-refractory epilepsy(1, 2). MRI-guided stereotactic laser ablation interstitial thermal therapy (MRgLITT) is a minimally-invasive surgical option, achieving seizure freedom in approximately 80% of all patients(3) while demonstrating safety and efficacy in pediatric and adolescent populations(4). From a technical standpoint, this technique allows for the selective ablation of periventricular lesions not favorable to an open approach (5).
H&P Patient is a 25 year-old male with structural brain abnormalities and focal epilepsy with seizures starting at age 14 years. He has been refractory since age 19.
Imaging MRI revealed polymicrogyria (PMG) involving bilateral parieto-occipital regions. In addition, there were areas of gray matter heterotopia along the left lateral ventricle. MRI fingerprinting demonstrated higher T1 and T2 intensity in the L cortical malformations. DTI demonstrated a connection between the L PMG and lateral temporal lobe. SEEG revealed 2 GTC seizures and 1 focal unaware seizure from the L PMG.
Procedure Robotic Stereotactic Implantation of Two Laser Ports in the Lateral Position followed by MRI-guided Laser Ablation of L PMG.
Post-op Imaging Post-op CT demonstrates no acute hemorrhage. Post-op MRI demonstrates approximately 13ccs of L periventricular gray matter was ablated.
Surgical Outcomes and Follow-up Patient was discharged on POD 1 following steroid taper.
Keywords Stereotactic, minimally invasive, magnetic resonance thermal therapy, laser ablation, epilepsy
Evaluation and Management of Vermian Tumors
Authors: Ellina Hattar, MD; Tyler D. Alexander, MS; Thiago S. Montenegro, MD; Glenn A. Gonzalez, MD; Kevin Judy,
MD; James S. Harrop; MD
Online Publication Date: Jan 2021
Epidemiology Vermian tumors are rare and differ in type based on patient factors. In adults, they are most commonly due to metastasis.1
H&P A 64-year-old male with a history of lung nodule presented with six months of progressively imbalance and dizziness and a neurologic exam significant for severe truncal ataxia.
Imaging Imaging revealed a 3.5 cm enhancing tumor of the cerebellar vermis effacing the fourth ventricle without hydrocephalus.
Procedure Two approaches can be used to access vermian lesions: the telovelar (TL) and transvermian (TR).2–4 The TL approach makes use of natural corridors through the cerebellomedullary fissure, while the TR approach is employed for tumors extending to the rostral fourth ventricle.5,6 In this case, the TR approach was used as the tumor extended into the rostral fourth ventricle and approached the vermian surface.
Surgical Outcomes and Follow-up Postoperative imaging demonstrated a complete resection. Pathology was consistent with metastatic carcinoma of lung origin. Postoperatively, the patient’s dizziness and imbalance improved over the course of several weeks.
Conclusion Both the TL and the TR approaches are viable routes to the fourth ventricle. An understanding of the anatomic limitations of each approach is necessary to avoid a postoperative neurologic deficit.
Anterior Cervical Discectomy and Fusion (ACDF): Case Report and Surgical Video
Authors: Kevin Hines MD, Liam P. Hughes BA, Ritam Ghosh MD, Caio M. Matias MD, PhD, Jack Jallo MD, PhD
Online Publication Date: Feb 2021
Epidemiology Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure for anterior compressive pathology of the cervical spine, allowing for direct decompression of the spinal cord. Since its implementation it has been associated with significant improvement in neurological symptoms including radiculopathy and myelopathy, and with low morbidity and mortality.
H&P 69-year-old female with a PMH of hyperlipidemia who presented with 7 months of significant neck pain, gait dysfunction, and left upper extremity (LUE) pain. Patient also endorsed biceps and triceps weakness as well as paresthesias affecting her left thumb. Physical exam confirmed LUE motor weakness and sensory deficits. Patient also had a positive Romberg sign, and hyperreflexia in the patellar tendons, bilaterally.
Imaging Magnetic resonance imaging (MRI) study with gadolinium demonstrated degenerative disc disease with central and foraminal stenosis worst at C5-6 and C6-7.
Procedure Patient underwent successful ACDF at the C5-6 and C6-7 levels.
Surgical Outcomes Postoperative imaging confirmed satisfactory implant placement. On POD #1 patient was discharged home with no complications and proper pain management. At 1-month follow- up patient had no complications and was progressing well. Strength in left arm and balance had improved.
Keywords: ACDF, cervical spine, medical education
Acute Sciatica from Non-Compressive Mass: Mobile Epidermoid Inclusion Cyst of
the Lumbar Spine
Authors: Elias Atallah MD, Victor Sabourin MD, Liam P. Hughes BA, Glenn A. Gonzalez MD, Anthony Stefanelli MD, Madeline Reganis DO, Karim Hafazalla MD, D. Mitchell Self MD, Chengyuan Wu MD MSBmE, James S. Harrop MD
Online Publication Date: March 2021
Epidemiology Spinal epidermoid cysts represent less than 1% of all spine tumors. Patients usually present with pain and neurologic dysfunction that includes muscle weakness and atrophy, sensory disturbances, and loss of sphincter control.
H&P The patient is a 60-year-old female. She presented with three weeks of significant low back and bilateral lower extremity pain. On examination, she had full strength in all motor groups and denied any, dysesthesia, bowel or bladder dysfunction, saddle anesthesia, or gross hematuria.
Imaging Magnetic resonance imaging (MRI) study with gadolinium demonstrated a 9mm intradural extramedullary lesion at the level of the L5-S1 vertebral bodies, in contact with the left S1 nerve root.
Procedure Patient underwent laminectomy which revealed a mobile, pearl-like mass which was fully resected. Histopathological analysis demonstrated mature stratified squamous epithelium and abundant flaky keratin consistent with an epidermoid cyst.
Surgical Outcomes Postoperative imaging demonstrated a complete resection. Studies have shown that the mean time to presentation after the precipitating event for acquired epidermoid cysts was ~9 years. Acute presentation may have occurred due to tumor content spillage causing chemical meningitis, or the mobility of the mass, as it was connected but not fixed to the cauda equine nerves.
Keywords: Epidermoid cyst, spinal cord tumor, sciatica
Evaluation of a patient with foot drop: differentiating between radiculopathy and peroneal nerve palsy
Authors: Tyler D. Alexander MS; Christopher J. Elia DO; Ryan McDonald BS; Sara Thalheimer BA; James Harrop, MD
Online Publication Date: March 2021
Epidemiology Foot drop is characterized by a weak anterior tibialis muscle on dorsiflexion. It most commonly results from pathology arising from the L4/L5 level but can also arise due to other causes.1 Hereditary motor sensory neuropathy (HMSN) is an inherited group of peripheral nerve disorders, associated with decreased production of proteins in or myelination of peripheral nerves – which can also present with foot drop. Charcot Marie Tooth disease (CMT) is the most commonly inherited HMSN – with a prevalence of around 40 per 100,000.2 Up to 36% of patients with CMT present with peroneal nerve palsy, which can also present with a foot drop. In a patient with foot drop, it is important to distinguish whether the cause is secondary to stenosis at L4/L5 or a peroneal nerve palsy such as CMT.
H&P A patient presented with loss of dorsiflexion of the left foot (foot drop) and loss of arches on the left foot. The patient was able to invert his foot but was unable to evert the foot. The patient also had normal sensation along the dorsum of the left foot.
Diagnosis In order to differentiate a deep peroneal nerve palsy from L4/L5 radiculopathy, the patient’s ability to invert and evert the foot was tested. Furthermore, because L4/L5 radiculopathy can affect the superior and inferior gluteal nerves, the patient’s intact gluteal muscles and tensor fasciae lata decreased the likelihood of radiculopathy. The patient’s ability to invert but not evert, coupled with normal gluteal muscles and sensation along the anterior portion of the foot indicated a deep peroneal nerve palsy rather than L4/L5 stenosis.
Keywords: Peroneal nerve palsy, radiculopathy, foot drop, Charcot Marie tooth (CMT), hereditary motor sensory neuropathy (HMSN)