Raymond F. Sekula

Dimensions of the posterior fossa in patients symptomatic for Chiari I malformation but without cerebellar tonsillar descent

BackgroundChiari I malformation (CMI) is diagnosed by rigid radiographic criteria along with appropriate clinical symptomatology. The aim of this study was to investigate the dimensions of the posterior cranial fossa in patients without significant tonsillar descent but with symptoms comparable to CMI.MethodsTwenty-two patients with signs and symptoms comparable to CMI but without accepted radiographic criteria of tonsillar descent > 3–5 mm were referred to our clinic for evaluation. A history and physical examination were performed on all patients. In reviewing their MRI scans, nine morphometric measurements were recorded. The measurements were compared to measurements from a cohort of twenty-five individuals with cranial neuralgias from our practice.ResultsFor patients with Chiari-like symptomatology, the following statistically significant abnormalities were identified: reduced length of the clivus, reduced length of basisphenoid, reduced length of basiocciput, and increased angle of the tentorium. Multiple morphometric studies have demonstrated similar findings in CMI.ConclusionThe current classification of CMI is likely too restrictive. Preliminary morphologic data suggests that a subgroup of patients exists with tonsillar descent less than 3 mm below the foramen magnum but with congenitally hypoplastic posterior fossa causing symptomatology consistent with CMI.

Primary treatment of a blister-like aneurysm with an encircling clip graft: technical case report.

OBJECTIVE: Blister-like aneurysms at nonbranching sites in the supraclinoid portion of the internal carotid artery are a rare but important cause of subarachnoid hemorrhage. We report a case of subarachnoid hemorrhage caused by a ruptured blister-type aneurysm, review the pertinent literature, and hope to remind readers of the wisdom of the use of an encircling clip as the primary treatment of these challenging lesions. CLINICAL PRESENTATION: A 41-year-old woman presented with sudden onset of headache. An admission computed tomographic (CT) scan revealed thick and diffuse subarachnoid hemorrhage involving primarily the carotid cistern and the proximal left sylvian fissure. A cerebral angiogram was initially interpreted as absent for aneurysm, but a follow-up angiogram performed 1 week later confirmed an enlarging aneurysm. INTERVENTION: A craniotomy with placement of an encircling clip graft around a blister-like aneurysm was performed. CONCLUSION: Although Sundt advocated the encircling clip graft for the blister-type aneurysm almost 40 years ago, use of an encircling clip graft in the treatment of blister-like aneurysms of the supraclinoid portion of the internal carotid artery seems to be reserved as a secondary or “rescue” measure in current practice. Neurosurgeons must familiarize themselves with this distinct entity (the blister-type aneurysm), recognize the possible risks associated with parallel clipping, and consider the use of an encircling clip graft as the primary treatment.

Epidemiology of ventriculostomy in the United States from 1997 to 2001

Ventriculostomy is a common practice in neurosurgery, but the annual trend of this procedure in the United States has not been reported in the literature. This study evaluates the annual trend during a recent 5-year period. Between 1997 and 2001, a retrospective review was undertaken concerning all patients in the Nationwide Inpatient Sample (NIS) who had undergone ventriculostomy. The population sample represented approximately a 20% stratified sample of nonfederal hospitals in the United States. The annual number of patients who underwent ventriculostomy during the study period ranged from 20,586 to 25,634. Most patients were male (53.4%), with a mean age of 44.8 years, were commercially insured (46.0%) and had a median annual income above

MRI Findings in Patients with a History of Failed Prior Microvascular Decompression for Hemifacial Spasm: How to Image and Where to Look

25,000 (84.4%). Most frequent ICD-9-CM diagnoses were subarachnoid haemorrhage, intracerebral haemorrhage and obstructive hydrocephalus, respectively. The majority of ventriculostomies were performed in large, private, not-for-profit, metropolitan, teaching institutions. Mean length of hospital stay was 19.2 days. Regarding discharge status for patients who had undergone ventriculostomy, approximately one-quarter died in the hospital, one-third were discharged home and one-third were transferred to another institution. No demographic variables changed during the study with the exception of location of ventriculostomy in a teaching hospital, which increased from 64.4% in 1997 to 77.4% in 2001. Patient and hospital demographic characteristics were consistent during the study period. By extrapolation of the data, the prevalence of ventriculostomy in the United States averaged 24,380 per year. This study is the first to comprehensively document data concerning the epidemiology of this common procedure.

Microvascular decompression for hemifacial spasm in patients >65 years of age: an analysis of outcomes and complications.

BACKGROUND AND PURPOSE: A minority of patients who undergo microvascular decompression for hemifacial spasm do not improve after the first operation. We sought to determine the most common locations of unaddressed neurovascular contact in patients with persistent or recurrent hemifacial spasm despite prior microvascular decompression. MATERIALS AND METHODS: Eighteen patients with a history of a microvascular decompression presented with persistent hemifacial spasm. All patients underwent thin-section steady-state free precession MR imaging. Fourteen patients underwent repeat microvascular decompression at our institution. Images were evaluated for the following: the presence of persistent vascular compression of the facial nerve, type of culprit vessel (artery or vein), name of the culprit artery, segment of the nerve in contact with the vessel, and location of the point of contact relative to the existing surgical pledget. The imaging findings were compared with the operative findings. RESULTS: In 12 of the 18 patients (67%), persistent vascular compression was identified by imaging. In 11 of these 12 patients, the culprit vessel was an artery. Compression of the attached segment (along the ventral surface of the pons) was identified in most patients (58%, 7/12). The point of contact was proximal to the surgical pledget in most patients (83%, 10/12). The imaging interpretation was concordant with the surgical results regarding artery versus vein in 86% of cases and regarding the segment of the nerve contacted in 92%. CONCLUSIONS: In patients with persistent hemifacial spasm despite microvascular decompression, the unaddressed vascular compression is typically proximal to the previously placed pledget, usually along the attached segment of the nerve. Re-imaging with high-resolution T2-weighted MR imaging will usually identify the culprit vessel.

The pathogenesis of Chiari I malformation and syringomyelia.

Few data are available to quantify the risks and benefits of microvascular decompression (MVD) in elderly patients with hemifacial spasm.

Exclusion of cervical spine instability in patients with blunt trauma with normal multidetector CT (MDCT) and radiography

Abstract Objective: The pathogeneses of Chiari malformation type I and syringomyelia are incompletely understood. In this article, the authors attempt to review the current theories on the pathogeneses of Chiari I malformation and syringomyelia. Methods: A literature review for articles pertaining to Chiari I malformation or syringomyelia before August 2010 was conducted; in addition, the author’s own experience in treating Chiari I malformation and syringomyelia is included. Results: Chiari I malformation has been defined radiographically as cerebellar tonsillar herniation or ectopia 5 mm or greater below the foramen magnum. By this narrow definition, Chiari I malformation (i.e. cerebellar tonsillar herniation or ectopia 5 mm or greater below the foramen magnum) likely encompasses a heterogeneous grouping of disorders caused by different mechanisms. Molecular and genetic studies have been helpful in furthering our understanding of Chiari I malformation. Conclusion: A review of the pathogeneses of Chiari I malformation and syringomyelia is reported.

MRI of the Trigeminal Nerve in Patients With Trigeminal Neuralgia Secondary to Vascular Compression.

The objective of the study was to determine if negative multidetector computed tomography (MDCT) and lateral radiography of the cervical spine effectively excludes patients with unstable cervical spine injuries. Over a period of 40 months, 6558 people were admitted to our trauma service with blunt injury and 447 (6.8%) were found to have cervical fractures. Fractures were identified by CT and/or lateral radiography. In order to rule out clinically significant instability in the absence of fracture, we identified nine patients who required any type of stabilization of the cervical spine including anterior fusion, posterior fusion and external orthosis. These patients also underwent MR of the cervical spine. Radiography, CT, and MR images and reports of these nine patients were reviewed. Nine patients without a fracture required cervical stabilization. These patients had the following abnormalities: disc herniation with canal stenosis in three, unilateral jumped facet in three, and various other soft tissue abnormalities in three, all of which were evident on CT or radiography. All nine patients had evidence for cervical spine injury or instability by MDCT. Normal MDCT and radiography appears adequate to ‘clear’ the cervical spine. We recommend that patients requiring cervical spine clearance undergo a complete MDCT and lateral radiograph of the cervical spine. If these studies are entirely normal, then the cervical spine may be cleared. If any abnormalities, including disc herniation, soft tissue swelling and bony malalignments are noted by radiography and/or MDCT, further studies, including MR, are indicated prior to clearance of the cervical spine.

Calcium Phosphate Cement Cranioplasty Decreases the Rate of Cerebrospinal Fluid Leak and Wound Infection Compared with Titanium Mesh Cranioplasty: Retrospective Study of 672 Patients

OBJECTIVE Trigeminal neuralgia is a debilitating facial pain disorder, frequently caused by vascular compression of the trigeminal nerve. Vascular compression that results in trigeminal neuralgia occurs along the cisternal segment of the nerve. CONCLUSION Imaging combined with clinical information is critical to correctly identify patients who are candidates for microvascular decompression. The purpose of this article is to review trigeminal nerve anatomy and to provide strategies for radiologists to recognize important MRI findings in patients with trigeminal neuralgia.

Imaging-Based Features of Headaches in Chiari Malformation Type I

OBJECTIVE A variety of biomaterials have been developed for cranial reconstruction after craniectomy, including polyethylene titanium mesh and calcium phosphate cement. This study sought to compare complication rates of calcium phosphate cement and titanium mesh cranioplasty in patients undergoing retromastoid craniectomy. METHODS The authors retrospectively reviewed clinical data from 672 consecutive patients who underwent retromastoid craniectomy at a single institution for microvascular decompression or tumor resection from July 2009 to July 2014. Of these, 336 patients received calcium phosphate cement cranioplasty and 336 underwent (polyethylene) mesh cranioplasty. Charts were abstracted for occurrence of cerebrospinal fluid (CSF) leak, wound infection and/or other wound complication, and the groups were compared. RESULTS In the mesh cranioplasty group, there were 38 complications related to the surgical site, including 18 infections (5.4%), 20 patients (6%) with CSF leak or pseudomeningocele, and no (0%) other wound complications. In the cement cranioplasty cohort, 2 patients (0.6%) experienced wound infection, no patients (0%) had CSF leak, and 2 patients (0.6%) had other wound complications (including one sterile wound dehiscence and one reoperation for removal of excess cement). There was a statistically significant decrease in the rate of wound infection and CSF leak in the patients who underwent cement cranioplasty (P <0.001 for both). CONCLUSIONS Calcium phosphate cement cranioplasty offers an alternative to titanium cranioplasty and may reduce the risk of surgical site complication. Randomized, prospective comparisons of cement cranioplasty to traditional techniques are warranted.