Localization of internal auditory canal in the middle cranial fossa approach: a study in Chinese based on CT reconstruction technique / 上海交通大学学报（医学版）

Objective • To study how to localize the internal auditory canal in the middle cranial fossa approach in Chinese using CT reconstruction technique. Methods • Forty-four cases (88 sides) of normal temporal bone CT data were selected, including 22 males and 22 females. The anatomical structures of the middle cranial fossa including the skull base, the internal auditory canal and the superior semicircular canal were reconstructed in 3D. The angle between great superficial petrosal nerve and internal auditory canal, the angle between superior semicircular canal and internal auditory canal and the osseous thickness above internal auditory canal were measured. The angle and distance were statistically analyzed in different sex and side groups. Results • On the reconstructed 3D middle cranial base, the arcuate eminence could only be identified in 43% cases. The angle between great superficial petrosal nerve and internal auditory canal was 51.46˚±9.28˚; the angle between superior semicircular canal and internal auditory canal was 49.22˚±7.32˚; the osseous thickness above internal auditory canal was (4.38±0.97) mm. No gender or side difference was noticed. Conclusion • There are significant individual differences in angulation and distance between the internal auditory canal and its related anatomical structures. CT reconstruction technique is helpful for accurate localization of the internal auditory canal.

A Case of Recurred Cholesteatoma Removal via Middle Cranial Fossa Approach / 대한이비인후과학회지

Cholesteatoma is a benign disease but it has an aggressive feature that may lead to serious conditions. Many strategies have been introduced for the treatment cholesteatoma, yet no definite single method has been established: it should be treated respectively regarding the completion of cholesteatoma, conservation of tympanic mucosa, proper ventilation of middle ear and preservation of hearing. A 25-year old patient visited our clinic for right-sided facial paralysis of 5 days. The patient underwent canal wall down mastoidectomy 10 years ago due to cholesteatoma and a few revision surgeries under local anesthesia for recurrence. Pre-operative temporal bone CT showed suspected recurred cholesteatoma in internal auditory canal and labyrinthine segment of facial nerve nearby. The patient underwent a removal of cholesteatoma via middle cranial fossa approach. This case report is a successful completion of recurred cholesteatoma, for which no recurrence is shown. Facial nerve function is improved at postoperative 1 year.

A Case of Image-Guided Acoustic Neuroma Surgery via Middle Cranial Fossa Approach / 대한이비인후과학회지

Acoustic tumor which originates from the vestibular nerve is the most common neoplasm to be found at the cerebellopontine angle. The surgical approaches currently used for the acoustic tumor are the middle cranial fossa, the translabyrinthine, the suboccipital, and the combined approaches depending on the size, location, and growth rate of the tumor and the hearing level, age, and general health condition of the patient. The complex and variable anatomy and the proximity of important structures encountered during acoustic tumor surgery especially when using the middle cranial fossa approach, may make it a tough job even for the experienced surgeon. Recently, developed image-guided system may be an important step in reducing the incidence of the complication. In the present research, authors used image-guided system during acoustic tumor surgery via middle cranial fossa approach, and with good result.

Hearing preservation and surgical complications after extended middle cranial fossa approach / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The advent of magnetic resonance imaging has enabled surgeons to detect small intracanalicular tumors. Therefore, many patients with acoustic tumors can be candidates for hearing preservation. This study was designed to analyze hearing results following acoustic tumor removal through the extended middle cranial fossa approach (EMCFA) and to determine the prognostic factors associated with successful hearing preservation. MATERIALS & METHODS: We retrospectively reviewed 11 patients whose tumor was removed via EMCFA (10:acoustic tumor, 1:lymphangioma). RESULTS: In 9 patients, the tumors were completely removed with EMCFA and in one patient, the suboccipital approach was combined with EMCFA. However, the approach was transformed to the translabyrinthine approach in one patient, because the tumor adhered to the cochlear nerve. The overall success rate of hearing preservation was 60% (6 of 10). In 20% of patients, the hearing was worse and other 20% of patients lost their hearing. Preoperative hearing level, location of tumor and origin of tumor affect the postoperative hearing. But tumor size did not relate to hearing preservation. CONCLUSION: In most cases, we could preserve the patient's hearing with EMCFA. However, the patients with poor preoperative hearing and tumor originated from the superior vestibular nerve were at risk for hearing loss.