[Usefulness of hyperbaric oxygen in the treatment of radionecrosis and symptomatic brain edema after LINAC radiosurgery]

Radionecrosis with brain edema is a complication of radiosurgery. Three female patients harbouring a frontal pole, petrous and parasagital parietoocipital meningiomas respectively who had been treated with LINAC radiosurgery are presented. Those patients developed, between two and eight months later, a severe symptomatic radionecrosis with a huge brain edema resistant to the usual steroid therapy. Only after 40 sessions of hyperbaric oxygen, a good remission of the lesions was obtained. There are few cases reported in the literature with such a good outcome. Consequentely, this therapy must be taken into account to treat this type of radiosurgical complication before considering surgery.

[Management of cerebellopontine angle meningiomas and the posterior part of the temporal bone. Report on 44 cases]

OBJECTIVES

To review and study the management of CPA meningiomas through the experience of an otoneurosurgical team.

MATERIAL AND METHODS

Fourty-two patients (44 meningiomas) were considered. Seventy-seven per cent of tumors (34 cases) were operated on; 6 tumors (14.6%) were exclusively irradiated using fractionated radiation therapy (FRT) and four only surveyed (9,8%).

RESULTS

transpetrosal approaches were exclusively used. These were translabyrinthine (TLA) in 47%, widened retrolabyrinthine (WRLA) in 41% of cases, transcochlear approach (TCA) in three cases and a middle fossa in one. A transtentorial approach was combined in 35% of cases (8 TLA, 4 WRLA). Surgical removal was incomplete in 11,8% of cases; in 3 cases growing tumor was treated by FRT included one case of anaplasic tumor Postoperative complications were: 1 meningitis, 1 wound abscess, 2 hydrocephalus (6%) and 4 CSF fistulas (12%). No complications have been observed during the last 7 years (21 cases). House and Brackmann Grade 1 or 2 facial function was obtained in 59% of cases (but 10 patients had a preoperative facial nerve paresis). A normal or subnormal AAO-HNS Class A-B Hearing could be preserved in 57% of WRLA. Radiation therapy allowed tumor shrinkage in all cases. In 3 cases this regression was of more than 50%.

CONCLUSION

Surgery is the gold standard in treating CPA meningiomas. Transpetrosal approaches and particularly WRLA pure or combined to a transtentorial approach are for us the best way to remove these tumors in preserving hearing and facial nerve function. When hearing is poor or when tumor extension to the clivus or the premeatal area is consistent a TLA is either planned preoperatively or obtained from a WRLA.

Nausea as a complication of low-frequency repetitive transcranial magnetic stimulation of the posterior fossa

BACKGROUND

Transcranial magnetic stimulation (TMS) can non-invasively investigate the function of human brain. However, it can induce a focal pain at the stimulated site on the scalp or seizures when applied with high frequency (>1 Hz). Here we report an induction of nausea as a complication of low-frequency repetitive TMS (rTMS) of the cerebellum.

SUBJECTS AND METHODS

Eight right-handed normal volunteers underwent low-frequency (0.9 Hz) rTMS of the right cerebellum. The stimulus intensity was set at 90% of the resting motor threshold determined by TMS to motor cortex.

RESULTS

Nausea lasted as long as 10 min after the end of rTMS without apparent neurological deficit in two subjects. This symptom was replicated when the same protocol was applied on a different day in the same subjects.

CONCLUSIONS

Low-frequency rTMS of cerebellum is still a safe procedure, but the experimenters should keep in mind the possibility of inducing nausea.

Preoperative and postoperative auditory and facial nerve function in cerebellopontine angle meningiomas

Preoperative and postoperative facial nerve and auditory function were reviewed retrospectively in 13 cases of cerebellopontine angle meningiomas. According to their location within the posterior fossa and with special reference to the internal auditory canal, they were classified into a premeatal and a retromeatal group. All the tumors were removed by an otoneurosurgical team by use of a retrosigmoid approach. Postoperative results (1 year after operation) were compared within the two groups with respect to preservation of hearing (normal hearing in 31% and preservation of preoperative hearing in 69% of the cases) and facial nerve function (no or mild postoperative impairment in 69% of the cases). Both preoperative and postoperative impairment of facial nerve and auditory function prevailed in the premeatal group. For preservation of vital vascular and central nervous structures, subtotal resection with consecutive fractionated radiation therapy had to be performed in 30% of the cases. Our results provide substantial evidence that in cerebellopontine angle meningiomas a precise preoperative study of tumor location will assist in improving individual operative strategy and thus postoperative functional results.