A novel proposed grading system for cerebellar arteriovenous malformations.

OBJECTIVE: The objective of this study was to evaluate the existing Spetzler-Martin (SM), Spetzler-Ponce (SP), and Lawton-Young (LY) grading systems for cerebellar arteriovenous malformations (AVMs) and to propose a new grading system to estimate the risks associated with these lesions. METHODS: Data for patients with cerebellar AVMs treated microsurgically in two tertiary medical centers were retrospectively reviewed. Data from patients at institution 1 were collected from September 1999 to February 2013, and at institution 2 from October 2008 to October 2015. Patient outcomes were classified as favorable (modified Rankin Scale [mRS] score 0-2) or poor (mRS score 3-6) at the time of discharge. Using chi-square and logistic regression analysis, variables associated with poor outcomes were assigned risk points to design the proposed grading system. The proposed system included neurological status prior to treatment (poor, +2 points), emergency surgery (+1 point), age > 60 years (+1 point), and deep venous drainage (deep, +1 point). Risk point totals of 0-1 comprised grade 1, 2-3 grade 2, and 4-5 grade 3. RESULTS: A total of 125 cerebellar AVMs of 1328 brain AVMs were reviewed in 125 patients, 120 of which were treated microsurgically and included in the study. With our proposed grading system, we found poor outcomes differed significantly between each grade (p < 0.001), while with the SM, SP, and LY grading systems they did not (p = 0.22, p = 0.25, and p = 1, respectively). Logistic regression revealed grade 2 had 3.3 times the risk of experiencing a poor outcome (p = 0.008), while grade 3 had 9.9 times the risk (p < 0.001). The proposed grading system demonstrated a superior level of predictive accuracy (area under the receiver operating characteristic curve [AUROC] of 0.72) compared with the SM, SP, and LY grading systems (AUROC of 0.61, 0.57, and 0.51, respectively). CONCLUSIONS: The authors propose a novel grading system for cerebellar AVMs based on emergency surgery, venous drainage, preoperative neurological status, and age that provides a superior prognostication power than the formerly proposed SM, SP, and LY grading systems. This grading system is clinically predictive of patient outcomes and can be used to better guide vascular neurosurgeons in clinical decision-making.

The Unique Features and Outcomes of Microsurgically Resected Cerebellar Arteriovenous Malformations.

BACKGROUND: Cerebellar arteriovenous malformations (CAVMs) are challenging to treat given their close proximity to the brain stem, greater propensity for rupture, and greater rates of morbidity and mortality than other brain arteriovenous malformations. The present investigation sought to describe and characterize the features of these rare and unique lesions. METHODS: A retrospective review of CAVM cases treated at 2 tertiary medical centers was performed. Patients surgically treated at institution 1 from September 1999 to February 2013 and institution 2 from October 2008 to October 2015 were included. RESULTS: A total of 120 patients had been treated. Of the 120 patients, 85 (70.8%) had initially presented with hemorrhage, 45 (37.5%) of whom experienced hemorrhage requiring emergent surgery. A favorable neurological outcome was observed in 76 patients (63.3%; modified Rankin Scale score <3). The perioperative mortality was 2.5% (n = 3). The long-term mortality rate was 7.5% (n = 9). The mean follow-up time was 1.82 years. On average, the patients with large CAVMs (≥3 cm; P ≤ 0.001), who had received embolization before surgery (P = 0.04), did not have an associated aneurysm (P ≤ 0.001), or had a residual CAVM after surgery (P = 0.008) were significantly younger. Female patients had fewer CAVMs with deep venous drainage (54.3% vs. 72.3%; P = 0.049), experienced decreased mortality (1.4% vs. 16.7%; P = 0.003), and were less likely to have worse neurological status after treatment (P = 0.003). CONCLUSIONS: CAVMs are rare lesions that exhibit unique disease characteristics. Although most patients will experience a favorable outcome, CAVMs frequently present with hemorrhage, result in high rates of morbidity and mortality, and characteristically differ depending on patient age and gender.

Falxuplication, a Novel Method for Wrap-Clipping a Fusiform Aneurysm: Technical Note.

BACKGROUND: Various techniques have been used for wrap-clipping a ruptured, fusiform intracranial aneurysm; however, there is no available literature on use of the falx cerebri for wrap-clipping. We present a review of the literature, with an illustrative case, of a ruptured fusiform pericallosal artery aneurysm firmly attached to the lower edge of the falx cerebri and not amenable to endovascular intervention. METHODS: Although the firm attachment between the inferior falx and the fusiform aneurysm was maintained, a section of the lower thinner part of the falx cerebri firmly attached to the aneurysm was dissected and wrapped around the fusiform aneurysm, and then stabilized with a fenestrated clip. We chose a segment slightly longer than the length of the fusiform aneurysm to avoid pre- and post-wrap-clipping stenosis. RESULTS: Postprocedure, except for a small area of numbness on the left distal anterolateral left leg, the patient was neurologically intact and remained neurologically intact at a 12-month follow-up. CONCLUSIONS: An inferior thin segment of the falx cerebri can be used for wrap-clipping of ruptured fusiform anterior cerebral artery aneurysms. Furthermore, the inferior falx can be wrapped around the attached fusiform anterior cerebral artery aneurysm without compromising flow, offering a safe solution in these unusually complex cases.

Cranial Osteomyelitis: A Comprehensive Review of Modern Therapies.

BACKGROUND: Cranial osteomyelitis is a rare but potentially life-threatening condition that requires early diagnosis with prompt and appropriate management by neurosurgeons to prevent further central nervous system complications. METHODS: The literature in the Medline database was comprehensively reviewed with the keywords "cranial osteomyelitis," "skull base osteomyelitis (SBO)," "central skull base osteomyelitis," and "temporal bone osteomyelitis." Items in the reference list of each article relevant to the objective of this study were reviewed. RESULTS: This review produced 183 articles: 13 book chapters, 24 case reports, 17 case series, 98 original articles, 30 review articles, and 1 meta-analysis. We classified cranial osteomyelitis as sinorhino-otogenic, including anterior, middle, and posterior skull base osteomyelitis; and non-sinorhino-otogenic, including iatrogenic, posttraumatic, hematologic, and osteomyelitis with other causes. CONCLUSIONS: New diagnostic modalities, the introduction of broad-spectrum antibiotics, and recent advances in neurosurgical procedures have led to a decrease in the rate of treatment failure in cranial osteomyelitis. Early recognition of initial nonspecific symptoms is key to diagnosing and managing this treatable but life-threatening condition. Early identification of the causative pathogen, appropriate broad-spectrum antibiotic therapy over a period of 8-20 weeks, and aggressive surgical debridement are essential for managing cranial osteomyelitis. On the other hand, inadequate treatment is responsible for refractory cases and poses a great diagnostic challenge. A new classification dividing cranial osteomyelitis into sinorhino-otogenic versus nonsinorhino-otogenic groups could prove valuable for clinical communication and treatment.

Subarachnoid Trabeculae: A Comprehensive Review of Their Embryology, Histology, Morphology, and Surgical Significance.

INTRODUCTION: Brain is suspended in cerebrospinal fluid (CSF)-filled subarachnoid space by subarachnoid trabeculae (SAT), which are collagen-reinforced columns stretching between the arachnoid and pia maters. Much neuroanatomic research has been focused on the subarachnoid cisterns and arachnoid matter but reported data on the SAT are limited. This study provides a comprehensive review of subarachnoid trabeculae, including their embryology, histology, morphologic variations, and surgical significance. METHODS: A literature search was conducted with no date restrictions in PubMed, Medline, EMBASE, Wiley Online Library, Cochrane, and Research Gate. Terms for the search included but were not limited to subarachnoid trabeculae, subarachnoid trabecular membrane, arachnoid mater, subarachnoid trabeculae embryology, subarachnoid trabeculae histology, and morphology. Articles with a high likelihood of bias, any study published in nonpopular journals (not indexed in PubMed or MEDLINE), and studies with conflicting data were excluded. RESULTS: A total of 1113 articles were retrieved. Of these, 110 articles including 19 book chapters, 58 original articles, 31 review articles, and 2 case reports met our inclusion criteria. CONCLUSIONS: SAT provide mechanical support to neurovascular structures through cell-to-cell interconnections and specific junctions between the pia and arachnoid maters. They vary widely in appearance and configuration among different parts of the brain. The complex network of SAT is inhomogeneous and mainly located in the vicinity of blood vessels. Microsurgical procedures should be performed with great care, and sharp rather than blunt trabecular dissection is recommended because of the close relationship to neurovascular structures. The significance of SAT for cerebrospinal fluid flow and hydrocephalus is to be determined.

Rare Concurrent Retroclival and Pan-Spinal Subdural Empyema: Review of Literature with an Uncommon Illustrative Case.

BACKGROUND: Subdural empyema can present as a spinal subdural empyema (SSE) or a cranial subdural empyema (CSE). Although they differ somewhat in epidemiology, etiology, pathophysiology, and symptomatology and occur separately, they rarely manifest together. The aim of this article is to review the literature concerning the clinical presentation, clinical course, and treatment options for managing concurrently occurring SSE and CSE. METHODS: The literature in the Medline database was reviewed with key words including but not limited to subdural empyema, retroclival empyema, and Streptococcus mitis. No similar reports were found in the database involving infection with this type of microorganism in this anatomical region. RESULTS: Only 3 cases with concurrent CSE and SSE were found in the literature caused by various etiologic agents. Two of the patients recovered with no neurologic deficit, whereas one fatality was reported. One new illustrative case caused by Streptococcus mitis is also presented. CONCLUSIONS: CSE and SSE are neurosurgical emergencies, often requiring prompt surgical evacuation. Although very rare, Streptococcus mitis can cause spinal subdural empyema or retroclival abscesses. Natural history of this disease is grave without treatment. Delays in diagnosis and treatment are directly related to mortality and severe morbidity in patients with intracranial and spinal subdural empyema. Prompt recognition and treatment are essential to preclude severe neurologic disabilities or in rare cases a fatal outcome. A treatment paradigm for cranio-spinal empyema is proposed.