Superior semicircular canal dehiscence (SSCD) syndrome is an unusual cause of vertigo that was first identified by Minor in 1998. The patients initially described by Minor presented with vertigo, oscillopsia and/or dysequilibrium related to sound, changes in middle ear pressure and/or changes in intracranial pressure due to an absence of the bony layer that normally covers the superior semicircular canal.1Subsequent clinical studies have shown that the condition may lead to a variety of vestibular and/or auditory symptoms that mimic other otologic disorders. These symptoms include autophony, ear blockage or fullness, conductive hearing loss, pulsatile tinnitus, dizziness or vertigo with head movements and general disequilibrium.
Human ; SEMICIRCULAR CANALS ; IMAGE PROCESSING, COMPUTER-ASSISTED ; IMAGE RECONSTRUCTION ; TOMOGRAPHY SCANNERS, X-RAY COMPUTED ; VERTIGO ; SYMPTOMS ; SIGNS AND SYMPTOMS ; DIAGNOSIS

A new method to fabricate exact-fit medical implants is proposed. Medical image processing and digital geometry processing are adopted for bone triangular mesh modeling from CT image series. After geometric operations such as decimation, defragmentation, cutting and mirroring are applied to the original triangular mesh, an RP model of same size as the bone is fabricated with LOM method. RP models are used for manufacturing exact-fit implants and they also serve surgery-guiding purpose. This novel technique has been applied in over 30 clinical cases, and it is proven to be practicable.
Humans ; Image Processing, Computer-Assisted ; Mandible ; Mandibular Reconstruction ; Maxilla ; Models, Theoretical ; Reconstructive Surgical Procedures

This paper is to report our study in which the differences between prosthetic restoration and surgical reconstruction using traditional clasp retention technology were analyzed based on three-dimensional finite element methods in our laboratory. Firstly, the maxillary unilateral defect model was developed using medical image processing software MIMICS. Secondly, the prosthesis was generated by mirroring technology. The clasp was designed according to the methods raised by Aramany. Then, the stress distribution of maxilla was calculated by simulating occlusion. According to the results, after osseointegration of surgical reconstruction, stresses of unaffected abutments were reduced significantly, and less stress of junction occurred near zygoma of affected side, which were all less than stresses of prosthesis restoration. Thus, removing the clasp of surgical reconstruction increased the stresses of unaffected abutments. The stress trends of maxillary components were different between prosthetic restoration and surgical reconstruction. Surgical reconstruction is better than prosthesis restoration in protection of the abutments. Clasp can alleviate the occlusal burden of maxilla. Varieties of retentive technologies can be considered in prosthesis restoration. The surgical reconstruction is more conducive to rehabilitate unilateral maxilla biomechanically in clinic.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Image Processing, Computer-Assisted ; Mandibular Reconstruction ; methods ; Maxilla ; surgery ; Maxillofacial Prosthesis ; Osseointegration ; Zygoma