Plical resection in pre-temporal approach for basilar bifurcation aneurysms: preliminary surgical experience and cadaveric study.

OBJECT: Although a pre-temporal approach (PA) can provide a wide space for preservation of thalamoperforating atrteries in direct surgery for basilar bifurcation aneurysms (BBAs), it cannot always secure adequate proximal control. The authors described the advantages of plical resection added to PA for BBAs. METHODS: Between October 1998 and April 2000, eight consecutive patients with BBAs were treated in the neurosurgical department of Kurashiki Central Hospital. Among them, five patients received direct clipping using this method. There were four females and one male, ages ranging from 61 to 77 (mean 70.8 years). Mean aneurysmal size and distance between the in"terclinoidal line and the aneurysmal neck was 4.5 and 9.5 mm, respectively. The operative procedures consisted of the following components; 1) fronto-temporal craniotomy with translocation of orbito-zygomatico-malar bone for PA, 2) preservation of lateral branches of the superficial sylvian veins, 3) resection of plica dural folds to increase the operative field up to the oculomotor nerve (OMN). RESULTS: Complete clipping was achieved without thalamic infarction or temporal contusion in all patients. Three of the five patients suffered from transient right OMN palsy which recovered within two months after surgery. CONCLUSION: Plical resection in the pre-temporal approach might be beneficial in the surgical treatment of BBAs when proximal control seems difficult.

Inheritance pattern of familial moyamoya disease: autosomal dominant mode and genomic imprinting.

BACKGROUND: Although the aetiology of moyamoya disease (MMD) has not been fully clarified, genetic analysis of familial MMD (F-MMD) has considerable potential to disclose it. OBJECTIVE: To determine the inheritance pattern and clinical characteristics of F-MMD to enable precise genetic analyses of the disease. METHODS: 15 highly aggregated Japanese families (52 patients; 38 women and 14 men) with three or more affected members were examined. The difference in categories of age at onset (child onset, adult onset and asymptomatic) between paternal and maternal transmission was compared by chi2 statistics. RESULTS: In all families there had been three or more generations without consanguinity, and all types of transmission, including father-to-son, were observed. Among a total of 135 offspring of affected people, 59 (43.7%) were patients with MMD or obligatory carriers. Affected mothers were more likely to produce late-onset (adult-onset or asymptomatic) female offspring (p = 0.007). CONCLUSIONS: The mode of inheritance of F-MMD is autosomal dominant with incomplete penetrance. Thus, in future genetic studies on F-MMD, parametric linkage analyses using large families with an autosomal dominant mode of inheritance are recommended. Genomic imprinting may be associated with the disease.

Use of the prone oblique position in surgery for posterior fossa lesions.

BACKGROUND: The lateral suboccipital approach has been conventionally performed with the lateral, park-bench, or sitting position and the midline suboccipital approach has been performed in the prone position. We attempt to show the advantages of the prone oblique position in the surgery for posterior fossa lesions. METHODS: Twenty-two patients with posterior fossa lesions underwent surgery in the prone oblique position. The patients were fixed in the prone position while the operating table was rotated to raise the patient's shoulder. The surgeon sat beside the downward-shifted contralateral shoulder of the patient. With the lateral suboccipital approach, the neck of the patient was rotated to the side of the lesion. With the midline suboccipital approach, the neck was not rotated. FINDINGS: With the lateral suboccipital approach, this position spread the transverse axis of the suboccipital triangle and eliminated the interference of the patient's shoulder, providing an operative field that is wider than the lateral position or park bench position in all cases. With the midline suboccipital approach, this position enabled the surgeon to operate on lesions located in the upper half of the posterior fossa, such as fourth ventricular lesions or infratentorial lesions, without the need for a looking up posture with overhanging of the operative microscope. CONCLUSION: The prone oblique position offers the operator a panoramic view of the posterior fossa.