ABSTRACT
OBJECTIVE Congenital aural atresia repair is difficult owing to unpredictable anatomy. Benefits may be gained from image-guided surgery(IGS) . its exact role and surgery indication were def ined. METHODS From 2001 to 2004,36 ears with bony type C(Schuknecht classification) congenital atresia were performed. In the IGS group(n=18) ,repair surgery was performed with IGS,while in the control group(Non-IGS,n=18) ,similar intervention was applied without IGS. IGS group:aged from 12-29 years,follow-up from 6 months to 1 year. Non-IGS group:aged from 10-27 years,follow-up from 6 months to 3 years. Intra-and post-operative clinical and audiometric findings were compared. RESULTS All of the patients had congenital bony aural atresia,ossicles malformation,tympanic cavity hypoplasia and facial nerve malformation. IGS revealed a malformed horizontal semicircular canal hidden in the bony atresia plate during the operation while computed tomography(CT) did not show preoperatively. IGS computed tomography images correlated well with intra-operative findings,gave the surgeon more securityand reduced operative time(2 hours and 24 minutes) by 25 minutes. The prepare time increased 20 minutes(15-30 minutes) ,but total time decreased 5 minutes in IGS group. The registration accuracy was 0.6-1.3 mm,average 0.84 mm,which was suitable for the otologic surgery. There were 1 case in IGS group and 3 cases in Non-IGS group happened local aural restenosis after operation. But there were no facial nerve paralysis and hearing injury happened in both groups,and all of the patients got the satisfactory hearing after the hearing reconstruction(the air-bone gap with an average of IGS is 31.8dB,Non-IGS is 30.5dB) . CONCLUSION In our estimation,IGS is valuable for type C congenital aural atresia repair. It serves as an educational tool and a guide both for the experienced and inexperienced surgeons in critical situations where anatomical landmarks are distorted and approach is limited. There is no statistically significant between two groups on hearing improvement after operation.
ABSTRACT
OBJECTIVE To analyze for mutations of the PDS gene in patients with sensorineural hearing loss associated with enlarged vestibular aqueduct and analyze the molecular pathogenesis of enlarged vestibular aqueducts. METHODS Eighteen sporadic cases of large vestibular aqueduct syndrome and twelve control individuals with normal hearing were included in this study. Exons 6 and 9 of the PDS gene in all subjects were amplified by polymerase chain reaction and analyzed by direct DNA sequencing. RESULTS Analysis revealed 2 single base changes in exon 6 of one patient with large vestibular aqueduct syndrome. One was a G→C transversion at nucleotide position 611, and the other was a T→G transversion at nucleotide position 612, resulting in a predicted Gly→Ala substitution at position 204. No mutation in exons 6 and 9 of the PDS gene was found in the PDS gene of the control individuals. CONCLUSION Mutations of the PDS gene are responsible for the large vestibular aqueduct syndrome. Analysis of the PDS leftover sequence in patients with large vestibular aqueduct syndrome is the next step in elucidating the complicated causes of this disease.