ABSTRACT
<p><b>BACKGROUND</b>Minimally invasive surgery in skull base relying on searching for possible anatomic basis for endoscopic technology is controversial. The objective of this study was to observe the spatial relationships between main blood vessels and nerves in the cerebellopontine angle area and provide anatomic basis for lateral and posterior skull base minimally invasive surgery via endoscopic retrosigmoid keyhole approach.</p><p><b>METHODS</b>This study was conducted on thirty dried adult skulls to measure the spatial relationships among the surface bony marks of posterior cranial fossa, and to locate the most appropriate drilling area for retrosigmoid keyhole approach. In addition, we used 10 formaldehyde-fixed adult cadaver specimens for simulating endoscopic retrosigmoid approach to determine the visible scope.</p><p><b>RESULTS</b>The midpoint between the mastoid tip and the asterion was the best drilling point for retrosigmoid approach. A hole centered on this point with the 2.0 cm in diameter was suitable for exposing the related structures in the cerebellopontine angle. Retrosigmoid keyhole approach can decrease the pressure on the cerebellum and expose the related structures effectively which include facial nerve, vestibulocochlear nerve, trigeminal nerve, glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve, anterior inferior cerebellar artery, posterior inferior cerebellar artery and labyrinthine artery, etc.</p><p><b>CONCLUSIONS</b>Exact location on endoscope retrosigmoid approach can avoid dragging cerebellum during the minimally invasive surgery. The application of retrosigmoid keyhole approach will extend the application of endoscopic technology.</p>
Subject(s)
Adult , Humans , Cerebellopontine Angle , General Surgery , Endoscopes , Minimally Invasive Surgical ProceduresABSTRACT
<p><b>OBJECTIVE</b>To evaluate the stability of hearing results and complications in long-term following-up who underwent reconstruction surgery.</p><p><b>METHODS</b>Six hundreds and seventy five cases (700 ears) of congenital aural atresia were reviewed from January 1984 to January 2001 at the Department of Otorhinolaryngology Head and Neck Surgery, Tongren hospital. Except 40 ears undone hearing reconstruction, 635 cases (660 ears) underwent long-term following-up for 3 to 19 years, with an average of 7.9 years.</p><p><b>RESULTS</b>Stenosis and recurrent infection of the external auditory canal (EAC) were the most frequent complications. Stenosis was seen in 120 ears, and 2 ears re-atresia, with an incidence of 18.48% (122/660). Recurrent infection of the cavity and canal skin happened in 6 ears. Closure of the air-bone gap (ABG) post-operation were gained in all cases, and ABG gains 20 dB or more occurred in 512 ears (77.57%), but 30 dB or more in 231 ears (35%). Following-up results: Stable hearing results gained in 450 ears over the length of following-up; the hearing worsened than that of 3 weeks postoperatively occurred in 160 ears, including 2 ears with sensorineural hearing loss. Hearing deteriorated more than 20 dB happened in 35 ears, and 10-15 dB in others cases but still be improved compared with that of preoperation.</p><p><b>CONCLUSIONS</b>Atresiaplasty surgery in individuals with congenital aural atresia can yield reliable, lasting hearing results in 68.2% (450/660), with a low incidence of complications; the initial improved hearing deteriorated gradually over the first 6 months post-operation, which are related with the stenosis and infection of canal. Cavity adhesion, bony EAC re-growth, ossicular chain re-fixation or displace may affect the hearing results in some cases. Even unilateral aural atresia may benefit from the reconstruction surgery and achieve serviceable hearing results.</p>