Orientador: Antonio Guilherme Borges Neto, Ricardo Ramina / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T17:37:15Z (GMT). No. of bitstreams: 1 Cardoso_ArquimedesCavalcante_D.pdf: 2722209 bytes, checksum: 68aae3facfed4e8f5338b24a3994aadc (MD5) Previous issue date: 2007 / Resumo: O autor apresenta um estudo descritivo-retrospectivo, envolvendo 240 pacientes portadores de Schwannoma do Vestibular (SV) que foram operados em decúbito dorsal (posição de mastóide), monitorizados com doppler transtorácico, utilizando-se o acesso retrossigmóide transmeatal. A função do VII e VIII nervos cranianos foi monitorizada durante a cirurgia e a reconstrução da abertura do conduto auditivo interno (CAI) foi realizada com retalho vascularizado de duramáter, músculo e cola de fibrina. A exérese foi completa em 99% dos casos, com mortalidade de 1,6%. Houve preservação da função do nervo facial em 85% dos casos e da audição em 40% dos pacientes, com audição prévia e tumores menores de 1,5 cm. A incidência de fístula liquórica foi de 5,8% e meningite de 2,9%. Embolia gasosa foi registrada em 3% dos casos, não associada à mortalidade. O tratamento cirúrgico dos SV utilizando-se a posição de mastóide e o acesso retrossigmóide transmeatal tem várias vantagens, com baixa morbidade e mortalidade, permitindo elevadas taxas de remoção radical, com a cura do paciente. O estudo é comparado com outras séries cirúrgicas publicadas de grupos com grande experiência na cirurgia de SV, bem como em relação aos resultados de pacientes de outros grupos que foram submetidos a tratamento radioterápico. / Abstract: To evaluate the result of the surgical treatment of Vestibular Schwannoma (VS) operated in dorsal decubitus (mastoid position). Material and methods: 240 patients with VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7 and 8 cranial nerves was monitored during surgery and the opened internal auditory canal (ICA) was reconstructed using a vascularized dura flap, muscle and fibrin glue. Results: Complete tumor removal was achieved in 99% of the cases, with a mortality of 1.6%. The facial nerve function was preserved in 85% of cases and hearing in 40% of the patients (with preoperative hearing) with tumors of up 1, 5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8% and meningitis 2.9%. Venous air embolism was registered in 3% of cases; it was not associated to mortality. Conclusion: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low. / Doutorado / Neurologia / Doutor em Ciências Médicas

In retrospektiv angelegten Untersuchungen soll der Einfluss unterschiedlicher Operationsstrategien auf die Morbidität bei der Behandlung des Akustikusneurinoms aufgezeigt werden. In einer ersten Untersuchung wurde der Einfluss eines doppelten Verschlusses der Dura mater nach subokzipitaler Kraniotomie zur mikrochirurgischen Exstirpation eines Akustikusneurinoms im Hinblick auf die Vermeidung einer Liquorfistel analysiert. Hier wurden zwei Patientengruppen miteinander verglichen. Zum einen Patienten mit einem einfachen Duraverschluss, Duranaht plus alloplastisches Material epidural. Zum anderen Patienten mit einem doppelten Duraverschluss. Hier epidurales und subdurales alloplastisches Material plus Duranaht. Untersucht wurden das Auftreten von Liquorfisteln sowie die Häufigkeit von Wundheilungsstörungen. Es konnte keine signifikante Überlegenheit einer Operationstechnik zur Vermeidung von postoperativen Liquorfisteln gezeigt werden. In einer zweiten Untersuchung wurde der Zusammenhang einer inkompletten Resektion des Tumors (Belassen eines Kapselrestes) mit dem Ziel der Schonung des Nervus facialis untersucht. Hierzu wurden die postoperative Facialisfunktion sowie ein möglicherweise erhöhtes Rezidivrisiko im Verlauf betrachtet. Die postoperative Funktion des N. facialis wurde zwischen den Patientengruppen mit Kapselrest (inkomplette Entfernung) und ohne Kapselrest (komplette Entfernung) verglichen. Es zeigte sich bei vergleichbarer postoperativer Facialisfunktion kein signifikanter Unterschied im Auftreten von Rezidiven nach inkompletter Resektion. Nur gut ein Drittel der inkomplett resezierten Tumore zeigten im Nachbeobachtungszeitraum (im Mittel 52 Monate) überhaupt ein Wachstum.

Some patients suffer hearing loss in the early postoperative period following vestibular schwannoma (VS) excision despite having intact hearing immediately after surgery. As this phenomenon has rarely been documented or described, the putative mechanism remains vague. The objective of the current study was to document the patterns of change in behavioural and electrophysiological responses in patients following VS surgery to better describe the phenomenon of delayed hearing loss. In particular, we aimed to determine whether the impairment that eventually leads to delayed hearing loss is neural or cochlear in origin. Auditory function was monitored in six adult patients who underwent surgery at Christchurch Public Hospital for excision of unilateral vestibular schwannoma through the retrosigmoid approach. Patients were assessed pre- and postoperatively by puretone audiometry, speech audiometry, tympanometry, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR). When measurable hearing was demonstrated postoperatively, pure-tone audiometry, speech audiometry and ABR were assessed at 24 hour intervals following surgery. Transtympanic electrocochleography (ECochG) was carried out if wave I of the ABR was lost during the postoperative period. Postoperative monitoring revealed that 4 patients suffered permanent anacusis and the remaining 2 patients had permanent hearing preservation. There were no patients who experienced delayed hearing loss in the early postoperative period. A phenomenon similar to delayed hearing loss was observed in case 2 who demonstrated loss of ABR wave I on the 7th postoperative day. Postoperative ECochG recorded in this case showed an enhanced negative SP on the operated side. The findings of this study are discussed in detail with particular reference to the underlying pathophysiology.

Some patients suffer hearing loss in the early postoperative period following vestibular schwannoma (VS) excision despite having intact hearing immediately after surgery. As this phenomenon has rarely been documented or described, the putative mechanism remains vague. The objective of the current study was to document the patterns of change in behavioural and electrophysiological responses in patients following VS surgery to better describe the phenomenon of delayed hearing loss. In particular, we aimed to determine whether the impairment that eventually leads to delayed hearing loss is neural or cochlear in origin. Auditory function was monitored in six adult patients who underwent surgery at Christchurch Public Hospital for excision of unilateral vestibular schwannoma through the retrosigmoid approach. Patients were assessed pre- and postoperatively by puretone audiometry, speech audiometry, tympanometry, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR). When measurable hearing was demonstrated postoperatively, pure-tone audiometry, speech audiometry and ABR were assessed at 24 hour intervals following surgery. Transtympanic electrocochleography (ECochG) was carried out if wave I of the ABR was lost during the postoperative period. Postoperative monitoring revealed that 4 patients suffered permanent anacusis and the remaining 2 patients had permanent hearing preservation. There were no patients who experienced delayed hearing loss in the early postoperative period. A phenomenon similar to delayed hearing loss was observed in case 2 who demonstrated loss of ABR wave I on the 7th postoperative day. Postoperative ECochG recorded in this case showed an enhanced negative SP on the operated side. The findings of this study are discussed in detail with particular reference to the underlying pathophysiology.

名古屋大学博士学位論文 学位の種類 : 博士(医学)(課程) 学位授与年月日:平成22年9月28日 山崎雅弘氏の博士論文として提出された

Following vestibular schwannoma excision, a subset of cases has been reported in which hearing is present immediately after surgery, but is lost in the early postoperative period. Such cases have rarely been reported, and the postoperative audiological data collected from patients in these cases lacks the time resolution necessary to determine the pathophysiological mechanism responsible for the pattern of hearing loss. The present study aimed to more clearly define delayed hearing loss by collecting detailed data documenting changes in behavioural and electrophysiological auditory responses following vestibular schwannoma surgery. In particular, we aimed to use this data to determine the time course of changes in auditory function and to identify whether the site of impairment was cochlear or neural. Preoperative and daily postoperative monitoring of auditory function was performed in 19 patients undergoing vestibular schwannoma excision via the retrosigmoid approach at Christchurch Public Hospital. The pre- and postoperative assessment battery included pure-tone and speech audiometry, tympanometry, tone decay, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR) measurement. Intraoperative ABR was performed in four cases in which clear preoperative waveforms were present. Transtympanic electrocochleography (ECochG) was carried out if wave I was lost in the early postoperative period. Thirteen of the 19 patients suffered immediate anacusis following surgery and six had measurable hearing postoperatively. The behavioural and electrophysiological data collected in each case is discussed with regard to the likely pathophysiology of pre- and postoperative hearing loss. No patients demonstrated behavioural evidence of delayed hearing loss, however a gradual deterioration of ABR in the early postoperative period was observed in Case 16. ECochG and DPOAEs in this case indicated the presence of cochlear function although the patient presented with immediate postoperative anacusis in the ipsilateral ear. These results are consistent with postoperative retrograde degeneration of the cochlear nerve.

Following vestibular schwannoma excision, a subset of cases has been reported in which hearing is present immediately after surgery, but is lost in the early postoperative period. Such cases have rarely been reported, and the postoperative audiological data collected from patients in these cases lacks the time resolution necessary to determine the pathophysiological mechanism responsible for the pattern of hearing loss. The present study aimed to more clearly define delayed hearing loss by collecting detailed data documenting changes in behavioural and electrophysiological auditory responses following vestibular schwannoma surgery. In particular, we aimed to use this data to determine the time course of changes in auditory function and to identify whether the site of impairment was cochlear or neural. Preoperative and daily postoperative monitoring of auditory function was performed in 19 patients undergoing vestibular schwannoma excision via the retrosigmoid approach at Christchurch Public Hospital. The pre- and postoperative assessment battery included pure-tone and speech audiometry, tympanometry, tone decay, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR) measurement. Intraoperative ABR was performed in four cases in which clear preoperative waveforms were present. Transtympanic electrocochleography (ECochG) was carried out if wave I was lost in the early postoperative period. Thirteen of the 19 patients suffered immediate anacusis following surgery and six had measurable hearing postoperatively. The behavioural and electrophysiological data collected in each case is discussed with regard to the likely pathophysiology of pre- and postoperative hearing loss. No patients demonstrated behavioural evidence of delayed hearing loss, however a gradual deterioration of ABR in the early postoperative period was observed in Case 16. ECochG and DPOAEs in this case indicated the presence of cochlear function although the patient presented with immediate postoperative anacusis in the ipsilateral ear. These results are consistent with postoperative retrograde degeneration of the cochlear nerve.

In retrospektiv angelegten Untersuchungen soll der Einfluss unterschiedlicher Operationsstrategien auf die Morbidität bei der Behandlung des Akustikusneurinoms aufgezeigt werden. In einer ersten Untersuchung wurde der Einfluss eines doppelten Verschlusses der Dura mater nach subokzipitaler Kraniotomie zur mikrochirurgischen Exstirpation eines Akustikusneurinoms im Hinblick auf die Vermeidung einer Liquorfistel analysiert. Hier wurden zwei Patientengruppen miteinander verglichen. Zum einen Patienten mit einem einfachen Duraverschluss, Duranaht plus alloplastisches Material epidural. Zum anderen Patienten mit einem doppelten Duraverschluss. Hier epidurales und subdurales alloplastisches Material plus Duranaht. Untersucht wurden das Auftreten von Liquorfisteln sowie die Häufigkeit von Wundheilungsstörungen. Es konnte keine signifikante Überlegenheit einer Operationstechnik zur Vermeidung von postoperativen Liquorfisteln gezeigt werden. In einer zweiten Untersuchung wurde der Zusammenhang einer inkompletten Resektion des Tumors (Belassen eines Kapselrestes) mit dem Ziel der Schonung des Nervus facialis untersucht. Hierzu wurden die postoperative Facialisfunktion sowie ein möglicherweise erhöhtes Rezidivrisiko im Verlauf betrachtet. Die postoperative Funktion des N. facialis wurde zwischen den Patientengruppen mit Kapselrest (inkomplette Entfernung) und ohne Kapselrest (komplette Entfernung) verglichen. Es zeigte sich bei vergleichbarer postoperativer Facialisfunktion kein signifikanter Unterschied im Auftreten von Rezidiven nach inkompletter Resektion. Nur gut ein Drittel der inkomplett resezierten Tumore zeigten im Nachbeobachtungszeitraum (im Mittel 52 Monate) überhaupt ein Wachstum.

Background: The use of intraoperative neurophysiological monitoring, including direct nerve stimulation (especially the facial nerve), acoustic evoked potentials (AEP) and somatosensory evoked potentials (SSEP), is a helpful tool in the microsurgery of vestibular schwannoma to prevent nerve injury. Patient characteristics and intraoperative and postoperative variables might also influence the postoperative facial nerve function. The study was performed to investigate these variables and the intraoperative neurophysiological monitoring values. Methods: Seventy-nine patients with vestibular schwannoma were included consecutively into this study. Intraoperative neurophysiological monitoring, including SSEP, AEP, and direct nerve stimulation for facial and trigeminal nerve electromyography, was performed utilizing digital data storage in all cases. The intensity (in volts) of the direct stimulation and the latency (in ms) for the orbicularis oculi and the orbicularis oris muscle and the amplitude (in mV) was measured. Univariate and multivariate statistical analyses concerning the different parameters was performed directly after the operation and in the subsequent follow-ups 3 and 6 months after the operation. Results: The mean intensity was 0.79 V (SD.29). The latency and amplitude for the oris muscle was 5.2ms (SD 2.07) and 0.68mV (SD.57), respectively. The mean latency for the occuli muscle was 5.58ms (SD 2.2) and the amplitude was 0.58mV (SD 1.04). The univariate and multivariate statistical analyses showed significance concerning the postoperative facial nerve function and the amplitude of the direct stimulation of the facial nerve in the orbicularis oris muscle (p = 0.03), so repeated direct nerve stimulation might show FN function deterioration. The mean diameter of the tumors was 24mm (range 10–57mm). Cross total resection and near total was achieved in 76 patients (96%) and subtotal in three patients (4%). The preoperative House–Brakeman score (HBS) 1 was constant in 65 (82%) cases. The mortality in our series was 0%; the overall morbidity was 10%. The HBS was not influenced concerning the extent of resection. The mean follow-up was 28 months (range 6 to 60 months). The limitations of the study might be a low number of patients and the retrospective character of the study. Conclusion: Intraoperative neurophysiological monitoring is crucial in vestibular schwannoma surgery. Repeated direct nerve stimulation and a detected decreased amplitude might show facial nerve function deterioration.

The aim of this diploma thesis is to evaluate spatial orientation in the patients after vestibular schwannoma surgery. In the theoretical part, there are summarized the facts about vestibular system; there is described the clinical picture of unilateral vestibular dysfunction and the field of vestibular schwannoma and spatial orientation in general. In the practical part, we performed the investigation of the spatial orientation using the Blue Velvet Arena System and posturography using the platform Balance Master® System. The purpose of the practical part was to find out, whether unilateral vestibular dysfunction in patients after vestibular schwannoma surgery has the impact on spatial orientation and to what extent is the postural stability influenced in patients identified for surgery and in patients after vestibular schwannoma surgery. Powered by TCPDF (www.tcpdf.org)