[Functional assessment of cochlear nerve and hearing]. / Exploration fonctionnelle du nerf cochléaire et de l'audition.

BACKGROUND/PURPOSE: Since otoneurosurgical pathologies are being diagnosed increasingly early, the functional prognosis of surgery is gaining in importance. Hearing and cochlear nerve exploration can be carried out using three principal methods: pure-tone and speech audiometry, evoked otoacoustic emissions (EOAEs), and brainstem auditory evoked potentials (BAEPs). The aim of this paper is to present the current knowledge on auditory functional assessment. MATERIALS AND METHODS: The medical and scientific literature from the Pubmed-Medline database was reviewed. Recently published related books were also included. RESULTS/DATA SYNTHESIS: Preoperative audiological evaluation makes it possible to assess pathology consequences on hearing. Depending on auditory status, conservative surgery, including intraoperative auditory monitoring, can be planned. From this perspective, prognostic factors for hearing preservation - such as the speech intelligibility score, the presence of transient EOAEs, and the presence of the BAEPs wave III - were identified. However, several surgical teams argue for a systematic conservative procedure, particularly when EOAEs are present, whatever the patient's preoperative hearing status. Postoperative audiological evaluation provides the opportunity for monitoring: in the short term, to detect complications early, through BAEPs recorded in the nonoperated ear; in the long term, to detect recurrence of the pathology. Moreover, the consequences of surgery on hearing can be assessed and long-term follow-up of auditory function can be carried out. Finally, the comparison of pre- and postoperative audiological status provides inductive feedback on surgery and electrophysiological monitoring, giving the otoneurosurgeon and neurophysiologist the opportunity to improve the entire procedure. CONCLUSION: Auditory functional assessment is essential for optimal care of tumor or functional pathologies involving the cochlear nerve and/or the cerebellopontine angle.

Assessment of the anatomical relationship between the arcuate eminence and superior semicircular canal by computed tomography.

The anatomical relationship between the arcuate eminence (AE) and the superior semicircular canal (SSC) was examined by computed tomography (CT) in 52 petrous bones of 26 patients. After acquiring volume data by multidetector CT, 1-mm thick oblique bone window images perpendicular to the SSC were obtained from the axial images. The distances between the AE and the SSC, and the SSC and the superior surface of the petrous bone were measured. The AE corresponded exactly with the SSC in only 2/52 petrous bones, and corresponded well in 7/52. The AE was lateral to the SSC in 25/52 cases, medial to the SSC in 6/52 cases, intersected in 3/52 cases, and was indiscernible in 9/52 cases. The distance between the SSC and the petrous surface was 0 mm in 45/52 petrous bones, 1 mm in 5/52, 2 mm in 1/52, and 3 mm in 1/52. The SSC typically does not correspond exactly with the AE, and is generally located just under the surface of the petrous bone. Planning of the middle cranial fossa approach requires location of the SSC by CT.

[Assessment of the state of water sectors in neurosurgical profile patients in the pre-, intra- and postoperative periods]. / Otsenka sostoianiia vodnykh sektorov u bol'nykh neirokhirurgicheskogo profilia v do-, intra- i posleoperatsionnom periodakh.

The state of water sectors has been analyzed at the stages of preparation to and performing anesthesia as well as in the early postoperative period in neurosurgical patients in connection with planned surgical procedures (37 cases). The impedance method of control of the hydration degree before operation allowed to find out a risk group--hypohydrated patients. In most cases the detected disturbances of the water-electrolytic balance could not be diagnosed clinically. Despite a relative stability of traditionally analyzed indices of circulation during anesthesia, the reactions of central hemodynamics were more pronounced than could be considered undesirable. The analysis performed makes a foundation for optimization of infusion and cardiotropic therapy both during anesthesiological maintenance of neurosurgical procedures and at the postoperative period.

Implementation of a clinical pathway in management of the postoperative vestibular schwannoma patient.

OBJECTIVE: The purpose of the study was to evaluate the effectiveness of a new clinical pathway in management of patients with postoperative vestibular schwannoma. The impact on duration of hospitalization and quality of care was evaluated. STUDY DESIGN: The study was a retrospective review of 59 consecutive patients undergoing surgical intervention for vestibular schwannoma between January 1995 and July 1999. METHODS: A new clinical pathway for management of postoperative vestibular schwannoma patients was implemented at The California Ear Institute at Stanford (Palo Alto, CA) in January 1995. All patients undergoing surgical intervention subsequent to initiation of the pathway were included in the study. Data including surgical approach, patient age, sex, and tumor size were included. Duration of hospitalization and postoperative complications were recorded. During the same time period, data for patients undergoing radiation therapy for vestibular schwannomas were evaluated for length of hospital stay and in-hospital complications. Data were compared with norms recorded in the literature for duration of hospitalization and complications following surgical intervention. RESULTS: Fifty-nine patients underwent 35 middle fossa approaches and 24 translabyrinthine approaches to their tumors. The average patient age was 53 years; there were 34 female and 25 male patients. The average length of hospital stay was 3.83 days (SD = 1.4 days) with a range from 2 to 10 days. Postoperative complications were observed in 19% of patients, including eight (13%) cerebrospinal fluid (CSF) leaks, two requiring lumbar drains (3.4%); one hematoma (1.6%), one postoperative fever (1.6%), and one dural tear with associated hyponatremia (1.6%). These results compared favorably with previously recorded average hospital stays of 5.95 to 9.5 days 1,5-7 and CSF leak complication rates of 7% to 15%.9,10 CONCLUSIONS: Implementation of a clinical pathway for management of the patient with postoperative vestibular schwannoma improves efficiency of patient care, allowing decreased duration of hospitalization. This goal is achieved without increasing complication rates and, in our experience, actually improving the quality of clinical care. The cost-effectiveness of clinical pathways may become increasingly important in a managed care-driven environment.