Superior vestibular neurectomy: a novel transmeatal approach for a denervation of the superior and lateral semicircular canals.

OBJECTIVE: To assess morphologically a transmeatal approach to the lateral and superior ampullary nerves performable under local anesthesia and simultaneously with the existing approach to the singular nerve developed by Gacek during the same operation. MATERIALS AND METHODS: Eighty halves of human heads preserved with the Thiel method were operated on by an otologist. Two surgical approaches were tested on each specimen, 1 superior and 1 inferior to the tympanic segment of the facial nerve. The 80 specimens were divided into 2 groups. In the first group, the osseous canal of the nerves of the lateral and superior semicircular canal were previously probed and next operated. In the second group, the osseous canal of the nerves were operated prior assessment by dissection. Afterward, all 80 halves underwent computed tomographic investigation to measure the distance between the entrance point of the drill in the medial wall of the tympanic cavity and the osseous canal the ampullary nerves. RESULTS: Inferior approach to the canal of the nerves could not be done without wide opening of the vestibulum in all 80 specimens. In the superior approach, the nerve could be reached directly in 5 cases, and only via the osseous ampulla of the lateral semicircular canal in 28 cases in the first group. In 7 cases, the nerves could not be reached without damage to the membranous labyrinth. In the second group, the nerve could be reached directly in 2 cases, via the osseous ampulla in 36 cases, and was unreachable in 2 cases. Significantly, distances longer than 3 mm between the surgical access and the nerve were found on the inaccessible cases. CONCLUSION: A transmeatal approach is possible superiorly but not inferiorly to the facial nerve, although it is necessary to open the osseous ampulla but not the membranous labyrinth in most cases.

[Jugular and tympanic paragangliomas]. / Les paragangiomes jugulaires et tympaniques.

Jugular and tympanic paragangliomas are the most frequent tumors of the middle ear. They appear as a reddish, pulsatile, retrotympanic mass. Patients complain from hearing loss and pulsatile tinnitus. Tumors are most often benign. Secretory forms are rare. Angio-MRI and CT-scan are gold standard. MIBG or octreotid scintigraphies are helpful to rule out multiple lesions. The treatment consists in surgery alone, radiotherapy alone or association of both. Often, embolisation prior to surgery decreases hemorrhagic risks. Vital prognosis is good. The functional outcome is critical in extensive tumors.

Development of surgical skill with singular neurectomy using human cadaveric temporal bones.

BACKGROUND: Profound anatomical knowledge and surgical experience are essential for safe otological surgery. The surgeon's learning curve is evaluated in performing Gacek's singular neurectomy on cadaveric specimens. MATERIALS AND METHOD: One otological surgeon performed Gacek's approach on 96 halves of human heads embalmed according to Thiel's method, divided into four groups (24 halves per group) and evaluated them concurrent to the evaluation of an anatomist after a first surgical attempt. Successful operations were subdivided into "direct hits" of the osseous canal of the posterior ampullary nerve also known as the singular nerve and "indirect hits" with access to the posterior ampullary recess. Unsuccessful operations showed "no hit" of the nerve without lesion of the membranous labyrinth. "Indirect" or "no hits" were reinvestigated in a second attempt to evaluate possible reclassifications due to a learning process of the surgeon. The order of dissection, the rate of success and the changes of results in correlation with the numbers of dissected specimens were documented. RESULTS: The success rate significantly increased from 54.2% direct hits after the first group to 87.36% in the fourth group after the first attempt. Successful operations were performed in 86.5% after completion of the first attempt and 97.9% after the second attempt. The number of new allocations decreased from 11 cases in the first group of dissected specimens to zero in the fourth group. CONCLUSIONS: This paper strengthens the value of cadaveric training for surgeons and the crucial role of dissection of a large number of specimens in improvement of the surgeon's experience and success rate.

Benign paroxysmal positional vertigo: a series of eight singular neurectomies.

CONCLUSION: The singular neurectomy as described by Gacek in 1974 is an efficient procedure to control symptoms in case of intractable benign paroxysmal positional vertigo (BPPV), with an acceptable risk of postoperative sensorineural hearing loss (SNHL). We postulate that this complication may not be a direct consequence of the surgical procedure but rather may be consecutive to the reactivation of the biological phenomenon that caused the BPPV. We also observed in one patient that BPPV may exist although no nystagmus can be elicited by provocative manoeuvres. OBJECTIVE: To report our experience of the surgery, and to analyse the rate and causes of complications. PATIENTS AND METHODS: The eight patients operated in the department between August 1997 and April 2006 were evaluated in June 2006. One had been operated because he had a typical history of BPPV, but no nystagmus could be elicited by the Hallpike's manoeuvre. RESULTS: All patients were free of vertigo and considered their quality of life improved. The Hallpike's manoeuvre was negative in all cases. A SNHL occurred in two patients, immediately after surgery in one and several months later in the second. The patient with a negative Hallpike's manoeuvre before surgery went back to work 3 weeks after surgery.