Ventral amygdalofugal pathway as an integrated surgically important network: microsurgical anatomy and segmentation based on fiber dissection.

OBJECTIVE: The ventral amygdalofugal pathway (VAFP) provides afferent and efferent connections to the amygdala and spans along some of the frequently traversed intra-axial surgical corridors as a dominant fiber bundle. This study aimed to reveal the frequently overlooked VAFP fibers by examining their courses and connections to the basal forebrain, septal region, hypothalamus, thalamus, tegmentum, and brainstem. METHODS: Ten postmortem human brains were used to display the characteristics of the VAFP, and fiber dissection results were compared with those of tractography. RESULTS: From anterior to posterior, the VAFP was separated into 5 different portions: 1) amygdala-substantia innominata; 2) amygdaloseptal (diagonal band of Broca); 3) amygdalo-thalamic; 4) amygdalo-hypothalamic, intermingling with the medial forebrain bundle and extending to the bed nucleus of stria terminalis; and 5) amygdalotegmental. The results of fiber dissections were confirmed with findings obtained from diffusion tensor tractography. CONCLUSIONS: This study supports the concept that interconnected forebrain, diencephalic, mesencephalic, and brainstem connections of the VAFP form an integrated surgically important network. The fiber dissection findings also provide the neuroanatomical basis for VAFP segmentation, which may help neurosurgeons better appreciate the complex microsurgical anatomy of the amygdalar connections. Amygdala-substantia innominata and amygdalotegmental connections are demonstrated for the first time and clarified within the structure of the VAFP.

Stereotactic Radiosurgery for Olfactory Groove Meningiomas: An International, Multicenter Study.

BACKGROUND: Stereotactic radiosurgery (SRS) is increasingly considered for selected olfactory groove meningiomas (OGMs). OBJECTIVE: To investigate the safety and efficacy of SRS for OGMs. METHODS: From 20 institutions participating in the International Radiosurgery Research Foundation, we pooled patients who underwent SRS for histologically confirmed or radiologically suspected WHO grade I OGMs and were followed for 6 mo or more after the SRS. RESULTS: In total, 278 (median age 57 yr) patients underwent SRS for histologically confirmed (29%) or radiologically suspected (71%) WHO grade I OGMs Median treatment volume was 4.60 cm3 (range: 0.12-27.3 cm3), median prescription dose was 12 Gy, and median dose to the olfactory nerve was 11.20 Gy. During median post-SRS imaging follow-up of 39 mo (range: 6-240 mo), 43% of patients had partial or marginal response, 54% of patients had stable disease, and 3% of patients experienced progression. During median post-SRS clinical follow-up of 51 mo (range: 6-240 mo), 36 (13%) patients experienced clinical and/or radiological adverse radiation events (AREs). Elevated risk of AREs was associated with larger OGM volume (P = .009) and pre-SRS peritumoral T2/fluid-attenuated inversion-recovery signal abnormalities (P < .001). After the SRS, olfaction remained stable, improved, or deteriorated in 90%, 8%, and 2% of patients, respectively. Complete post-SRS anosmia was predicted by partial/complete anosmia before the SRS (odds ratio [OR] = 83.125; 95% CI [24.589-281.01], P < .001) and prior resection of OGM (OR = 3.919; 95% CI [1.713-8.970], P = .001). CONCLUSION: SRS is associated with durable local control of the majority of OGM patients with acceptable safety profile. SRS allows preservation or improvement of olfactory function in the majority of OGM patients.

Simpson Grade 2 Resection and Tumor Recurrence in Ventrally Located Spinal Meningiomas.

AIM: To evaluate postoperative clinical outcome and recurrence rates in cases with ventrally located spinal meningiomas who underwent Simpson grade 2 resection. MATERIAL AND METHODS: We evaluated eight cases (six females and two males; age, 28?86 years; mean age, 60 years) with ventrally located spinal meningioma that underwent surgical treatment in our clinic. The tumors were located in the thoracic region in seven cases and in the cervical region in one case. All cases underwent surgery, which was performed using a traditional posterior midline approach. Laminectomy was unilaterally extended. The case with cervically located tumor differed from the other cases in that a skull clamp was used and laminoplasty was performed. RESULTS: The tumor was completely resected in all cases. Furthermore, in all cases, the tumor nidus that caused the thickening of the dura was cauterized using bipolar cautery and peeled off (Simpson grade 2). The pathological examination of the tumor specimens revealed typical grade 1 meningioma in all cases (fibropsammomatous type, n=1; meningothelial type, n=3; and psammomatous type, n=4). Recurrence was not observed in any of the cases during the follow-up. None of the cases demonstrated postoperative neurological deterioration. At 1 month postoperatively, pain and motor deficit completely improved in all cases, with remarkable improvements of motor deficits in the early postoperative period. CONCLUSION: Simpson grade 2 resection in ventrally located spinal meningiomas results in low complication rates and is satisfactory in terms of recurrence.

Can recurrence of chronic subdural hematoma be predicted? A retrospective analysis of 292 cases.

BACKGROUND: Chronic subdural hematomas are the most common type of intracranial hemorrhage among the elderly. There is a substantial recurrence rate after evacuation by burr-hole surgery. In this study, we aimed to determine the predictors of recurrence after single burr-hole evacuation of chronic subdural hematomas. METHODS: We retrospectively analyzed 292 consecutive patients with chronic subdural hematoma. Clinical parameters, anamnesis, and previous anticoagulant drug use have been evaluated with univariate and multivariate analyses to determine predictors associated with recurrence. RESULTS: At least a second surgery was needed in 43 of 292 (14.7%) patients. We showed that recurrence rate was significantly higher in patients with bilateral subdural hematoma, after univariate and multivariate analyses (23.1% versus 11.4%). We did not find any significant relationship between recurrence rate and age, gender, hypertension, and/or diabetes mellitus in anamnesis, preceding head trauma, and time interval between trauma and the operation, previous anticoagulant, and/or antiaggregant therapy. CONCLUSION: After analysis of all evaluated factors, only bilateral hematoma was found correlated with high recurrence rate (p = 0.01), probably due to previous brain atrophy or existing coagulopathy.