Jonathan Rasouli

Second Impact Syndrome: A Rare, Devastating Consequence of Repetitive Head Injuries

Sports-related concussion has been viewed as a developing public health crisis in recent years. Underrecognition of concussions can lead to premature clearance for athletic participation. Second impact syndrome (SIS) represents a rare, yet devastating, potential outcome of premature return to play. SIS is a condition in which rapid brain swelling occurs as a result of a repeat head injury sustained before symptoms of a previous head injury have resolved. Within minutes of the second impact, diffuse cerebral swelling, brain herniation, and death can occur. There are <20 documented cases of SIS in the world literature to date, and the general understanding of the syndrome is based largely on interpretation of anecdotal cases. This article reviews current understanding of the epidemiology and pathology of SIS. Given neurosurgeons’ role in management of head trauma, it is essential that neurosurgeons acquire and maintain thorough knowledge of concussion diagnosis, treatment, and management.

A review of modifying factors affecting usage of diagnostic rating scales in concussion management

Sport-related concussion has gained increasing recognition as a result of recent legislation, public health initiatives and media coverage. Moreover, there have been substantial paradigm shifts in the management of concussion. This article will discuss the variables that affect the use of diagnostic rating scales such as ImPACT and SCAT in the current management of concussed individuals. Specifically, patient-specific modifying factors affecting test interpretation, including age, gender, fitness level, psychiatric conditions, learning disorders and other components of medical history will be addressed, as well as methodological concerns with baseline testing.

Case Study of Image-Guided Deep Brain Stimulation: Magnetic Resonance Imaging–Based White Matter Tractography Shows Differences in Responders and Nonresponders

BACKGROUND The caudal zona incerta (cZI) is an increasingly popular deep brain stimulation (DBS) target for the treatment of tremor-predominant disease. The dentatorubrothalamic tract (DRTT) is a white matter fiber bundle that traverses the cZI and can be identified using diffusion-weighted magnetic resonance imaging fiber tractography to ascertain its precise course. In this report, we compare 2 patient cases of cZI DBS, a responder and a nonresponder. CASE DESCRIPTION Patient 1 (responder) is a 65-year-old man with medically refractory Parkinson disease who underwent bilateral DBS lead placement in the cZI. Postoperatively he demonstrated >90% reduction in baseline tremor and was not limited by stimulation side effects. Postoperative imaging showed correct lead placement in the cZI. Tractography revealed a DRTT within the field of stimulation, bilaterally. Patient 2 (nonresponder) is a 61-year-old man with medically refractory Parkinson disease who also underwent bilateral DBS lead placement in the cZI. He initially demonstrated >90% reduction in baseline tremor but developed disabling dystonia of his left leg and significant slurring of his speech in the months after surgery. Postoperative imaging showed bilateral lead placement in the cZI. Right-sided electrode revision was recommended and resulted in relief of tremor and reduced dystonic side effects. Tractography analysis of the original leads revealed a DRTT with an atypical anterior trajectory and a location outside the field of stimulation. Tractography analysis of the revised lead showed a DRTT within the field of stimulation. CONCLUSIONS Preoperative diffusion-weighted magnetic resonance imaging fiber tractography imaging of the DRTT has the potential to improve and individualize DBS planning.

Technical Note: Preemptive Surgical Revision of Impending Deep Brain Stimulation Hardware Erosion

BACKGROUND While deep brain stimulation (DBS) is a relatively safe procedure, skin erosion is a commonly reported hardware complication that can threaten the DBS system. Patients with Parkinson disease are especially at risk for this complication due to their autonomic dysregulation and impaired nutrition. Early detection of impending skin erosion allows for intervention that may prevent hardware destruction. Here we report a novel technique to address this complication preemptively. We describe the use of an acellular dermal matrix to prevent skin erosion in 20 patients with Parkinson disease who were treated with DBS and showed signs of impending skin erosion. METHODS Twenty patients with signs of impending hardware erosion were identified. An acellular dermal matrix was surgically placed under the at-risk skin overlying the DBS lead. RESULTS None of the 20 patients treated with this technique went on to require further revision surgery or removal of hardware. CONCLUSIONS Surgical placement of acellular dermal matrix in patients identified as having impending hardware erosions is a safe and cost-effective way to prevent hardware complications.

Review of Assessment Scales for Diagnosing and Monitoring Sports-related Concussion

Sports-related concussion has emerged as a public health crisis due to increased diagnosis of the condition and increased participation in organized and recreational athletics worldwide. Under-recognition of concussions can lead to premature clearance for athletic participation, leaving athletes vulnerable to repeat injury and subsequent short- and long-term complications. There is overwhelming evidence that assessment and management of sports-related concussions should involve a multifaceted approach. A number of assessment criteria have been developed for this purpose. It is important to understand the available and emerging diagnostic testing modalities for sports-related concussions. The most commonly used tools for evaluating individuals with concussion are the Post-Concussion Symptom Scale (PCSS), Standard Assessment of Concussion (SAC), Standard Concussion Assessment Tool (SCAT3), and the most recognized computerized neurocognitive test, the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). The strengths and limitations of each of these tools, and the Concussion Resolution Index (CRI), CogSport, and King-Devick tests were evaluated. Based on the data, it appears that the most sensitive and specific of these is the ImPACT test. Additionally, the King-Devick test is an effective adjunct due to its ability to test eye movements and brainstem function.

Simultaneous treatment of epilepsy and secondary dystonia after anterior temporal lobectomy and amygdalohippocampectomy

BACKGROUND The relationship between temporal lobe epilepsy and focal limb dystonia is a well-recognized phenomenon, yet its pathogenesis and anatomic foundation are not well understood. Here, we describe 2 patients with refractory focal epilepsy and contralateral focal limb dystonia whose seizures and dystonic symptoms simultaneously resolved after anterior temporal lobectomy and amygdalohippocampectomy. CASE DESCRIPTION We identified 2 patients within the Mount Sinai Health system with improvement in dystonia after medial temporal lobectomy. Retrospective chart reviews for the clinical history were performed. Patient 1 suffered a traumatic injury of the right temporal lobe, developing left hemidystonia and epilepsy. He received a right amygdala-hippocampectomy, which resolved both. Patient 2 has a history of right temporal glioma resection complicated by an infarct, resulting in left hemidystonia and epilepsy. He received a right medial temporal resection, which nearly resolved both. CONCLUSION Our cases demonstrate a medial temporal-basal ganglia network dysfunction in dystonia-epilepsy that was modulated and cured by resective surgery. We hypothesize that the mechanisms behind these observed phenomena were due to a pathologic connectivity of the basal ganglia and amygdala-hippocampus. To our knowledge, these are the first reported cases of dystonia and concomitant epilepsy resolving with temporal lobectomy and provide valuable prognostic information for similarly affected patients.

Deep brain stimulation of the ventralis intermedius nucleus for the treatment of essential tremor

A 59-year-old woman with a 30-year history of essential tremor refractory to medical therapy underwent staged deep brain stimulation of the ventralis intermedius nucleus of the thalamus (VIM). Left-sided lead placement was performed first. Once in the operating room, microelectrode recording (MER) was performed to confirm the appropriate trajectory and identify the VIM border with the ventralis caudalis nucleus. MER was repeated after repositioning 2 mm anteriorly to reduce the likelihood of stimulation-induced paresthesias. Physical examination prior to permanent lead placement demonstrated micro-lesion effect, suggesting optimal trajectory. After implantation of the permanent lead, physical examination showed excellent results. The video can be found here: https://youtu.be/nn3KRdmRCZ4 .

Primary extranodal marginal zone lymphoma involving the skull.

Extranodal marginal zone lymphoma (EMZL) is a rare cancer of B-lymphocyte origin typically found in the gastrointestinal tract within the mucosa-associated lymphoid tissue. EMZL accounts for 5% of all non-Hodgkins lymphomas and has been reported to affect the central nervous system in several select case reports. Here, we describe a rare case of EMZL presenting as an isolated skull mass, and review current management of EMZL. To our knowledge, this is the first reported patient of isolated EMZL of the skull.