RESUMO
BACKGROUND: An electrical potential not previously reported-electrical cochlear response (ECR)-observed only in implanted patients is described. Its amplitude and growth slope are a measurement of the stimulation achieved by a tone pip on the auditory nerve. The stimulation and recording system constructed for this purpose, the features of this potential obtained in a group of 43 children, and its possible clinical use are described. The ECR is obtained by averaging the EEG epochs acquired each time the cochlear implant (CI) processes a tone pip of known frequency and intensity when the patient is sleeping and using the CI in everyday mode. The ECR is sensitive to tone pip intensity level, microphone sensitivity, sound processor gain, dynamic range of electrical current, and responsiveness to electrical current of the auditory nerve portion involved with the electrode under test. It allows individual evaluation of intracochlear electrodes by choosing, one at the time, the central frequency of the electrode as the test tone pip frequency, so the ECR measurement due to a variable intensity tone pip allows to establish the suitability of the dynamic range of the electrode current. RESULTS: There is a difference in ECR measurements when patients are grouped based on their auditory behavior. The ECR slope and amplitude for the Sensitive group is 0.2 µV/dBHL and 10 µV at 50 dBHL compared with 0.04 µV/dBHL and 3 µV at 50dBHL for the Inconsistent group. The clinical cases show that adjusting the dynamic range of current based on the ECR improved the patient's auditory behavior. CONCLUSIONS: ECR can be recorded regardless of the artifact due to the electromyographic activity of the patient and the functioning of the CI. Its amplitude and growth slope versus the intensity of the stimulus differs between electrodes. The relationship between minimum ECR detection intensity level and auditory threshold suggests the possibility of estimating patient auditory thresholds this way. ECR does not depend on the subject's age, cooperation, or health status. It can be obtained at any time after implant surgery and the test procedure is the same regardless of device manufacturer.
Assuntos
Limiar Auditivo/fisiologia , Implantes Cocleares , Criança , Nervo Coclear/fisiologia , Potenciais Evocados Auditivos , Feminino , Humanos , MasculinoRESUMO
INTRODUCTION: Total mesorectal excision (TME) of the rectum has been advocated as the gold standard surgical treatment of middle and lower third rectal cancer. Laparoscopy has gained acceptance among surgeons in the treatment of colon malignancies, while scepticism exists about laparoscopic TME in terms of safety and its oncological adequacy. OBJECTIVE: To evaluate the impact of laparoscopic TME on surgical and oncological outcome in a group of consecutive unselected patients. METHODS: One hundred and thirty-two patients with middle or inferior rectal cancer were admitted to our unit and underwent TME from December 1998 to February 2008. Eighty-nine patients were approached with laparoscopy. Patients staged cT3/4 cTxN+ or uTxN+ were submitted to neoadjuvant treatment. Postoperative complications and oncological outcomes were registered. RESULTS: In the laparoscopic group 80 anterior resections (including 4 intersphincteric resections and manual colo- anal anastomosis) and 9 abdominal-perineal resections were performed. 33.3% of patients were enrolled in "long-course" neoadjuvant chemo-radiotherapy (partial and complete response rates 88.2% and 11.8%, respectively). Protective lateral ileostomy was performed in 72% of patients. Mean operative time was 254.3+/-38.3 min and mean blood loss was 215+/-180 ml. Conversion rate was 12.7%. Morbidity rate was 39.3% without mortality. The rate of anastomotic leaks was 13.48%, reoperation rate 13.48%, recovery rate 3.1+/-1.4 days and hospital stay 10.4+/-4.6 days. Concerning adequacy of oncologic resection, mean distance of the tumour from the anal verge was 4.3+/-2.2 cm. Nodal sampling of 12.4+/-4.8 were obtained. Six patients (6/89, 6.74%) had a R1 margin: 3 distal and 3 circumferential. Median follow-up was 29 months and local recurrence rate was 5.79%. Four-year cumulative overall survival was 78% and disease-free survival was 63% (Kaplan-Meier method). CONCLUSIONS: Laparoscopic approach for rectal tumour is a technically demanding procedure, but it is oncologically safe.