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R Shiobara

Publications and source records attributed to R Shiobara.

63 records · Page 4Linked to original sources
PubMed1975

[Early diagnosis and selection of operative approach for acoustic neuroma (author's transl)].

The recent advances of various diagnostic procedures made possible to detect intracanalicular neuroma in early stage. The operative results have been also greatly improved by transtemporal approach using surgical microscope and dental burr. In addition, the revised suboccipital approach contributed to obtain better operative results. Reviewing our clinical experiences with 15 cases operated from May 1969 to December 1971, appropriate combination of applicable diagnostic procedures and selection of operative method are discussed. Multiple audiologic examinations consisting of pure tone audiometry, speech discrimination, Békésy audiometry, alternate binaural loudness balance test, tone decay and uncomfortable lebel were performed in 11 cases. 9 of these cases manifested retrocochlear type of hearing loss. Spontaneous nystagmus and induced nystagmus, together with balance test, were evaluated for vestibular function. Bithermal caloric test disclosed unilateral canal paresis in all cases. In 13 cases, spontaneous nystagmus was observed. Analysis of optokinetic nystagmus using electronystagmography suggested tumor invasion to the brain stem and cerebellum. Tomography of the internal auditory canal showed abnormal findings in all cases. Cisternography with 2 ml of myodil was performed in 7 cases, all of which were diagnosed definitely by filling defect. Angiography showed abnormal vascular displacement with the tumor of size exceeding 3 cm in diameter. Translabyrinthine approach was performed in 5 cases. Suboccipital approach was applied in 6 cases. Combined approach of these two routes was used in 4 cases. 11 patients returned to their original work postoperatively. To obtain the correct diagnosis of acoustic neuroma in early stage, multiple audiologic examination are indispensable together with detailed vestibular function tests when the unilateral sensory neural hearing loss is suspected. Tomography of the internal auditory canal is also advisable as routine roentonologic study. If the clinical sign is confined to the 8th nerve only, myodil cisternography is useful, however, angiography is reliable in more advanced cases. When the tumor size is below 2 cm and signs of the spread to the brain stem, cerebellum or lower cranial nerves are lacking, translabyrinthine approach is indicated. Suboccipital approach is advisable for more advanced cases or undefinitive cases. Planning of combined approach of both routes is seemed to be not necessary in any case from our experience.

Adult↗
PubMedDate not supplied

Long-term prognosis of profound facial nerve paralysis secondary to acoustic neuroma resection.

The long-term prognosis of profound facial nerve paralysis was reviewed in 107 patients who, despite preserved nerve continuity, showed no facial movement after acoustic neuroma resection. Spontaneous recovery occurred in 77 patients. However, there was no apparent recovery in 30 patients. Twenty-two of these patients underwent hypoglossal-facial nerve anastomosis 7-33 months after tumor resection. When spontaneous recovery occurred, the first sign of remission was observed between 3 and 4 months after surgery in nearly half of the patients. Such a sign did not appear after 12 months. The recovery of facial movement deteriorated depending on how long remission onset was delayed. However, the quality of facial movement in patients with such delayed remission was still identical or better than that in those after hypoglossal-facial nerve anastomosis. These results showed that hypoglossal-facial nerve anastomosis should be performed approximately 1 year after tumor resection if no sign of remission has been observed by then.

Anastomosis, Surgical↗
PubMedDate not supplied

Electromyographic analysis of profound facial nerve paralysis following acoustic neuroma resection.

The aim of our retrospective study was to determine whether electromyographic findings (motor unit action potentials, MUAPs) can be used in long-term prognosis for profound facial nerve paralysis in patients whose nerve continuity is preserved during surgery for acoustic neuroma. The orbicularis oris, frontal, and orbicularis oculi muscles were examined for the occurrence of MUAPs in 48 such patients. In 30 patients who recovered from complete paralysis within 10 months after surgery, MUAPs in the first two muscles tended to precede the first sign of facial movement. MUAPs appeared in the orbicularis muscle in 80% of these patients at 1 month and in all at 5 months. In the frontal and orbicularis oculi muscles, MUAPs occurred in only 0-20% of these patients in the first month; within 3-5 months the number increased rapidly, and MUAPs were present in 95% of these patients at 10 months. In the remaining 18 patients with long-term complete paralysis (at least 1 year), MUAPs appeared solely in the orbicularis oris muscle: in 20% of these patients in the first month after surgery. While this number slowly rose, there was no period of rapid increase later. We conclude that the occurrence of MUAPs in the orbicularis oris and frontal muscles within 3 months of surgery indicates a good prognosis for reversal of facial nerve paralysis.

Anastomosis, Surgical↗
PubMedDate not supplied

Hearing preservation in acoustic neuroma surgery and postoperative audiological findings.

One hundred fifty-three cases of acoustic neuroma were treated surgically by the middle cranial fossa approach or extended middle cranial fossa approach. Attempts to preserve hearing were made in 30 cases with tumours extending 2.0 cm or less into the posterior fossa; successful hearing preservation was achieved in 12 cases. Among the 15 patients with preoperative hearing levels (HL) of 50 dB or lower and speech discrimination scores (SDS) of 50% or higher, hearing was preserved in 9 (60%) patients. A similar rate of hearing preservation was achieved among the patients with normal or near-normal hearing. Compared with those patients in whom hearing could not be preserved, those with hearing preservation had better HL, higher SDS, and less abnormal ABR findings preoperatively. Postoperatively, the HL and SDS deteriorated slightly. In addition, there was a marked prolongation of the IT5, and the incidence of absence of the stapedius reflex increased. Compared with the preoperative HL, the postoperative HL was unchanged in 5 cases; deteriorated temporarily and then improved in 5 cases; and deteriorated, though with hearing preserved, in 2 cases. Intraoperative monitoring was conducted by recording the ABR and VIII nerve compound action potentials and by electrocochleography. However, postoperative hearing could not always be predicted from the findings obtained at the end of the operation.

Audiometry↗