Presigmoid Transpetrosal Approach for Recurrent Acoustic Neurinomas: Indications and Surgical Results

OBJECTIVE: In order to facilitate total removal with preservation of the facial nerve, the authors applied presigmoid(PS) approach in some patients with recurrent acoustic neurinoma(AN) patients who had undergone previous retrosigmoid(RS) approaches. The surgical outcomes of PS approach were retrospectively analyzed and compared to those of RS approaches and we suggest the indication of PS approach for recurrent AN. METHODS: From 1989 to 1999, twenty-one of 183 operated AN patients underwent re-operation due to regrowth of the residual tumors. Nine of the 21 recurrent tumors were removed by PS approach and 12 cases underwent RS approach. The surgical extent of removal and the facial nerve preservation rate were compared between the two different approaches. RESULTS: In PS approaches, the total removal was achieved in four patients(44%) and the facial nerve could be identified and preserved anatomically in all patients. Among 12 cases who underwent RS approaches, the rate of total removal was 44% and the facial nerve identified and preserved in only 5 cases (42%). The rate of facial nerve preservation was significantly different between two modes of approaches (p=0.0007). CONCLUSION: PS transpetrosal approach is recommended in recurrent AN patients who had underwent RS approach previously and already lost the hearing. Early identification of the facial nerve and easy removal of the tumors can be achieved using the PS approach.

Preoperative Ocular Hypotensives and Early Ocular Hypertension after Cataract Surgery

Immediate postoperative changes in intraocular pressure (IOP) were prospectively studied in 60 patients after extracapsular cataract extraction and posterior chamber lens implantations, according to three different preoperative managements for cecreasing IOPs. In group 1 (24 patients), no ocular pressure reducing agents were given but only ocular massage was performed preoperatively. In group 2 (17 patients), intravenous mannitol (1.52g/kg of body weight) and/or 60ml of 50% oral glycerine was administered 1 hour before surgery. In group 3 (19 patients), 500mg of acetazolamide was administered orally 90 minutes before operation in addition to the regimen of group 2. A significant lllcrease in mean IOP was found 6 hours after the operation in group 1 by 5.6mmHg and in group 2 by 8.8mmHg when compared witt baseline IOP (p<0.05). However, there was no significant IOP rise in group 3. Postoperative IOPs in excess of 21mmHg occurred in 10 patients (42% )of group 1, seven patients (41 %) of group 2 and six patients(30%) of group 3. An IOP greater than 30mmHg was found in two patients (8%) in group 1, two patients (12%) in group 2 and one patient (5%) in group 3. From this study, it was concluded that acetazolamide 500mg given 90 minutes before operation resulted in a reduction of immediate postoperative IOP rise.

Early surgical management in bilateral acute retinal necrosis

One patient with bilateral acute retinal necrosis underwent encircling scleral buckle, vitrectomy, and intravitreal acyclovir on both eyes. This procedure was performed on the right eye while the retina was attached. The retina of the right eye was reattached by performing fluid-gas exchange and modified panretinal photocoagulation when the retina subsequently detached. Soon after the development of retinal detachment in the left eye, the above surgical procedures were performed on the left eye, and the retina was successfully reattached.Bilateral acute retinal necrosis with significant vitreous opacification, which is a devastating ocular disease causing possible blindness in both eyes, requires more aggressive, early surgical management.