Marcelo Campos Moraes Amato, Luis Fernando Tirapelli, Carlos Gilberto Carlotti Jr. and Benedicto Oscar Colli
Accurate knowledge of the anatomy of the straight sinus (SS) is relevant for surgical purposes. During one surgical procedure involving the removal of part of the SS wall, the authors observed that the venous blood flow was maintained in the SS, possibly through a vein-like structure within the dural sinus or dural multiple layers. This observation and its divergence from descriptions of the histological features of the SS walls motivated the present study. The authors aimed to investigate whether it is possible to dissect the SS walls while keeping the lumen intact, and to describe the histological and ultrastructural composition of the SS wall.
A total of 22 cadaveric specimens were used. The SS was divided into three portions: anterior, middle, and posterior. The characteristics of the SS walls were analyzed, and the feasibility of dissecting them while keeping the SS lumen intact was assessed. The thickness and the number of collagen fibers and other tissues in the SS walls were compared with the same variables in other venous sinuses. Masson's trichrome and Verhoeff's stains were used to assess collagen and elastic fibers, respectively. The data were analyzed using Zeiss image analysis software (KS400).
A vein-like structure independent of the SS walls was found in at least one of the portions of the SS in 8 of 22 samples (36.36%). The inferior wall could be delaminated in at least one portion in 21 of 22 samples (95.45%), whereas the lateral walls could seldom be delaminated. The inferior wall of the SS was thicker (p < 0.05) and exhibited less collagen and greater amounts of other tissues—including elastic fibers, connective tissue, blood vessels, and nerve fibers (p < 0.05)—compared with the lateral walls. Transmission electron microscopy revealed the presence of muscle fibers at a level deeper than that of the subendothelial connective tissue in the inferior wall of the SS, extending from its junction with the great cerebral vein to the confluence of sinuses.
The presence of a structure within the SS that can maintain the venous blood flow despite the dural wall might be considered an anatomical variation. The greater thickness of the inferior wall of the SS compared with the lateral walls is mainly due to the presence of larger amounts of tissues other than collagen. Delamination of the inferior wall of the SS was mostly possible in its inferior wall, but an attempt to delaminate the lateral walls is not recommended. Ultrastructural assessment corroborated a recent report of the presence of muscle fibers in the inferior wall of the SS.
Luis A. B. Borba, João Cândido Araújo, Jean G. de Oliveira, Miguel Giudicissi Filho, Marlus S. Moro, Luis Fernando Tirapelli and Benedicto O. Colli
The goal of this paper is to analyze the extension and relationships of glomus jugulare tumor with the temporal bone and the results of its surgical treatment aiming at preservation of the facial nerve. Based on the tumor extension and its relationships with the facial nerve, new criteria to be used in the selection of different surgical approaches are proposed.
Between December 1997 and December 2007, 34 patients (22 female and 12 male) with glomus jugulare tumors were treated. Their mean age was 48 years. The mean follow-up was 52.5 months. Clinical findings included hearing loss in 88%, swallowing disturbance in 50%, and facial nerve palsy in 41%. Magnetic resonance imaging demonstrated a mass in the jugular foramen in all cases, a mass in the middle ear in 97%, a cervical mass in 85%, and an intradural mass in 41%. The tumor was supplied by the external carotid artery in all cases, the internal carotid artery in 44%, and the vertebral artery in 32%. Preoperative embolization was performed in 15 cases. The approach was tailored to each patient, and 4 types of approaches were designed. The infralabyrinthine retrofacial approach (Type A) was used in 32.5%; infralabyrinthine pre- and retrofacial approach without occlusion of the external acoustic meatus (Type B) in 20.5%; infralabyrinthine pre- and retrofacial approach with occlusion of the external acoustic meatus (Type C) in 41%; and the infralabyrinthine approach with transposition of the facial nerve and removal of the middle ear structures (Type D) in 6% of the patients.
Radical removal was achieved in 91% of the cases and partial removal in 9%. Among 20 patients without preoperative facial nerve dysfunction, the nerve was kept in anatomical position in 19 (95%), and facial nerve function was normal during the immediate postoperative period in 17 (85%). Six patients (17.6%) had a new lower cranial nerve deficit, but recovery of swallowing function was adequate in all cases. Voice disturbance remained in all 6 cases. Cerebrospinal fluid leakage occurred in 6 patients (17.6%), with no need for reoperation in any of them. One patient died in the postoperative period due to pulmonary complications. The global recovery, based on the Karnofsky Performance Scale (KPS), was 100% in 15% of the patients, 90% in 45%, 80% in 33%, and 70% in 6%.
Radical removal of glomus jugulare tumor can be achieved without anterior transposition of the facial nerve. The extension of dissection, however, should be tailored to each case based on tumor blood supply, preoperative symptoms, and tumor extension. The operative field provided by the retrofacial infralabyrinthine approach, or the pre- and retrofacial approaches, with or without closure of the external acoustic meatus, allows a wide exposure of the jugular foramen area. Global functional recovery based on the KPS is acceptable in 94% of the patients.