Retrosigmoid Transmeatal Approach Research Articles

Intracanalicular vestibular schwannomas: facial and hearing outcomes according to the location of the tumor in relation to the nerves of the internal auditory canal.

The objective was to evaluate whether the position of the nerves within the internal auditory canal (IAC) has any effect on preoperative and postoperative cochlear and facial nerve function in patients with intracanalicular vestibular schwannoma (VS) resected through the retrosigmoid transmeatal approach. Forty-four patients with sporadic intracanalicular VS, from a series of 710 patients with VS who underwent operations from January 1993 to April 2022, were retrospectively reviewed. The pattern of displacement of the cranial nerves and tumor within the IAC was recorded. Tumors were divided into 2 types: type T1A lesions had only anteriorly displaced nerves, and type T1B had posteriorly displaced vestibular nerves and anteriorly displaced facial and cochlear nerves. Differences in surgical outcomes between groups in terms of facial nerve function and hearing preservation were evaluated. Thirty-five cases (79.5%) were T1A tumors and 9 were T1B (20.5%). Gross-total resection and anatomical preservation of the facial and cochlear nerves were achieved in all patients. Postoperatively, all patients with T1A VS maintained normal facial nerve function; however, among T1B VS patients, 6 (67%) retained House-Brackmann grade I, 2 worsened to grade II, and 1 worsened to grade III at 6 months (p = 0.006). The 27 T1A VS patients with serviceable hearing maintained this status, and an additional patient with nonserviceable hearing improved to serviceable hearing; among T1B VS patients, only 2 of the 5 patients with serviceable hearing remained as such, 2 evolved to nonserviceable hearing, and 1 lost hearing after surgery (p = 0.0022). T1B VS patients had a 24-fold risk of facial nerve deterioration (relative risk [RR] 25.2, 95% CI 1.42-448.57, p = 0.028) and a 32-fold risk of hearing deterioration (RR 32.7, 95% CI 1.93-553, p = 0.016) after surgery. In intracanalicular VS, postoperative cochlear and facial nerve function are directly related to the location of the tumor in relation to the nerves, with worse outcomes in cases where the tumor is located between the vestibular and facial-cochlear nerves.

Management of jugular bulb injury during retrosigmoid transmeatal resection of vestibular schwannoma

Inadvertent laceration of the jugular bulb is a potentially serious complication of the retrosigmoid transmeatal approach to vestibular schwannomas. Here, the authors present the case of a 51-year-old woman with a right Hannover T4a vestibular schwannoma and bilateral high-riding jugular bulb, which was opened during drilling of the internal auditory canal (IAC). They highlight the immediate management of this complication, technical nuances for closing the defect without occluding the jugular bulb, and modifications of the standard technique needed to continue surgical resection.The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2155

Endoscopic resection through a retrosigmoid transmeatal approach of a large-sized vestibular schwannoma: operative video and technical nuances.

Surgical management of vestibular schwannomas has improved over the last 30 years. Whereas in the past the primary goal was to preserve the patient’s life, today neurological function safeguarding is the main objective, with numerous strategies involving single resection, staged resections, postoperative radiosurgery, or single radiosurgery.The retrosigmoid approach remains the primary pathway for surgical access to the cerebellopontine angle (CPA). The use of an endoscope has great advantages. It contributes to the visualization and resection of residual tumor and also reduces the need for cerebellar retraction.The authors present a fully endoscopic resection of a large-sized vestibular schwannoma with facial nerve preservation.The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID21106

Microsurgery for Vestibular Schwannoma via Retrosigmoid Transmeatal Approach with Intraoperative Monitoring Techniques.

Background: Functional preservation of cranial nerves remains an issue in surgical treatment of vestibular schwannoma.Aims: To explore the functional outcomes of vestibular schwannoma removed by microsurgery via a retrosigmoid transmeatal approach with intraoperative monitoring techniques.Study Design: A retrospective cross-sectional study was conducted on a group of patients with vestibular schwannoma operated by microsurgery.Methods: The outcomes, including the extent of tumor removal, the anatomic positions of the facial nerve, and postoperative Karnofsky performance status score, facial nerve function, and hearing function were reviewed and were statistically compared among tumor sizes (small, medium, and giant) and intraoperative monitoring types [electrophysiological monitoring only (E), electrophysiological monitoring + intraoperative imaging examination (E+I), and electrophysiological monitoring + neuronavigation (E+N)].Results: A total of 436 patients with VS received microsurgery. The position of the facial nerve was anterior in 85.5% of cases with small vestibular schwannoma. Other position patterns, especially anterior–superior and anterior–inferior, increased in tumors > 2.0 cm. Total resections were performed in all patients with small vestibular schwannoma. A total of 98.1% and 84.8% of patients with medium and giant vestibular schwannoma, respectively, had total resections. More than 90% of patients in all of the 3 monitoring groups had total resections. More than 80% of patients had excellent Karnofsky performance status score regardless of tumor size and monitoring type. After surgery, 100%, 84.4%, and 59.8% of patients with small-, medium-, and giant-sized vestibular schwannoma, respectively, had good facial nerve function. More than 70% of patients in all of the 3 monitoring groups had good facial nerve function postoperatively. The hearing preservation rate was 26.7% and 7.7% in small- and medium-sized vestibular schwannoma, respectively, and was 21.6% and 27.3% in the E group and the E+N group, respectively. The statistical analyses showed that tumor size was significantly associated with the extent of tumor resection, facial nerve localization, complications, postoperative Karnofsky performance status score, facial nerve function, and hearing function (all P ≤ .001). Monitoring type was significantly associated with the extent of resection (P ≤ .001). Additionally, patients in the E+N group had higher total resection rates than those in the E group (P ≤ .001). No cerebrospinal fluid leakage and surgery-related death occurred.Conclusion: In vestibular schwannoma microsurgery, tumor size is an important parameter that affects the localization of the facial nerve, the extent of resection, postoperative outcomes and complications. Intraoperative electrophysiological techniques combined with neuronavigation may be helpful to improve the extent of resection.

Magnetic Resonance Imaging Surveillance for Vestibular Schwannoma After Microsurgical Resection Using a Retrosigmoid Transmeatal Approach

Vestibular schwannoma (VS) is a benign, usually slow-growing tumor. The drawback of radical microsurgical VS resection is the increased likelihood of neurologic injury, forcing surgeons to leave a tumor remnant in some cases. We evaluated the prognostic value of magnetic resonance imaging (MRI) enhancement patterns to determine the risk of tumor regrowth. This clinical study included 30 patients (20 women and 10 men) with VS who underwent surgery via a retrosigmoid transmeatal approach. The extent of resection was assessed by MRI 6 months after surgery. Two subtypes of intracanalicular linear enhancement were defined: linear enhancement of the walls of the internal auditory canal (IAC) or in the cerebellopontine angle (CPA) and linear enhancement covering the end of the IAC. All patients included in the study underwent follow-up MRI every year for at least 6 years. Intracanalicular nodular enhancement suggestive of a tumor remnant was seen in the IAC in 11 patients (36.7%). Volume of nodular enhancements was <0.5cm3 when measurable. The enhancement remained stable throughout follow-up except in 2 cases that showed a slight decrease in size and in 1 case with aninitial tumor remnant of 0.5 cm3 showing a slight increase over the years. Eighteen patients (60%) had linear enhancement in the IAC or in the CPA. No patientswith linear enhancement showed nodular enhancement. Although specific monitoring protocols can be designed based on MRI findings 6 months after microsurgical VS resection, follow-up should be maintained indefinitely given the slight possibility of very late regrowth.

Hearing preservation in vestibular schwannoma surgery via retrosigmoid transmeatal approach.

Advances in various diagnostic and/or treatment modalities, including radiological imaging, neuromonitoring, and microsurgical techniques, have resulted in treatments of vestibular schwannomas being aimed at preserving facial and hearing functions while achieving optimal tumor control. We describe our surgical technique for hearing preservation in vestibular schwannoma surgery. The retrosigmoid transmeatal approach under continuous neuromonitoring (auditory brainstem response, cochlear nerve action potentials, and continuous facial nerve monitoring) enables gross-total resection of vestibular schwannomas, while preserving hearing and facial functions. Radiological assessment and microsurgical techniques, such as meticulous tumor dissection, are also essential for functional preservation with sufficient tumor removal.

Retrosigmoid Transmeatal Approach for Resection of Acoustic Neuroma: Operative Video and Technical Nuances of Subperineural Dissection for Facial Nerve Preservation.

The retrosigmoid (suboccipital) approach is the workhorse for most acoustic neuromas in the cerebellopontine angle. In this operative video atlas manuscript, the authors demonstrate the nuances of the subperineural dissection technique for microsurgical resection of an acoustic neuroma via the retrosigmoid transmeatal approach. The plane is developed by separating the perineurium of the vestibular nerve away from the tumor capsule. This perineurium provides a protective layer between the tumor capsule and the facial nerve which serves as a buffer to avoid direct dissection and potential trauma to the facial nerve. Using this technique during extracapsular tumor dissection helps to maximize the extent of tumor removal while preserving facial nerve function. A gross total resection of the tumor was achieved, and the patient exhibited normal facial nerve function ( Fig. 1 ). In summary, the retrosigmoid transmeatal approach with the use of subperineural dissection are important strategies in the armamentarium for surgical management of acoustic neuromas with the goal of maximizing tumor removal and preserving facial nerve function ( Fig. 2 ). The link to the video can be found at: https://youtu.be/L3lPtSvJt60 .

Retrosigmoid Transmeatal Approach with 360-Degree Drilling of the Internal Auditory Canal for the Resection of Intracanalicular Meningioma.

Introduction Vestibular schwannomas are the most common lesions occupying the internal auditory canal (IAC); however, almost in 4 to 5% of meningiomas, metastases, cysts, lipomas, and cavernous malformations have been found in this location, mimicking schwannomas. Even though cerebellopontine angle (CPA) meningiomas with the involvement of the IAC are frequently encountered, the presence of a primary intracanalicular meningioma is rare. Objective To show the technical nuances of the retrosigmoid-transmeatal approach to successfully achieve gross total resection (GTR) with preservation of facial and auditory function. Case Report We present a left intracanalicular meningioma on a 60-year-old man with history of tinnitus and hearing loss. Magnetic resonance imaging (MRI) showed a left intracanalicular lesion completely obliterating the IAC and with minor extension to the CPA cistern, with the vestibulocochlear complex dislocated posteriorly, initially diagnosed as a Hannover's T2 vestibular schwannoma. The patient underwent a left retrosigmoid approach, and during the exposure of the lesion, the diagnosis of a meningioma became evident. The transmeatal phase of the approach was modified with a wide opening of the canal, including the anterior wall. Closure was performed using a muscle graft, duramater flap, and fibrin glue. Results GTR was achieved and the patient developed a mild facial palsy (House–Brackmann grade III) which completely recovered within 3 months. Conclusions The retrosigmoid transmeatal approach is suitable to achieve GTR in intracanalicular meningiomas. Some modifications of the approach intended for vestibular schwannomas are necessary and may be performed during the procedure. The link to the video can be found at: https://youtu.be/A9OXRFIl1e8 .

Retrosigmoid Approach for Vestibular Schwannoma

Vestibular schwannoma is a benign tumor that affects 3% of the population, but accounts for 85% of tumors occurring at the cerebellopontine angle (CPA). In this case, we present a 48-year-old female with history of cholesteatoma on the right and chronic suppurative otitis media on the left who presented with an 18 month history of bilateral hearing loss, worse on the right. Investigations revealed a right sided vestibular schwannoma measuring 1.6 cm in diameter. Audiogram revealed an AAO–HNS (American Academy of Otolaryngology–Head and Neck Surgery) class C hearing on the right and class B on the left. There are several management options for this size of vestibular schwannoma including observation and radiosurgery. However, preserving cochlear nerve function remains a challenging enterprise. Furthermore, the ideal management that confers the highest chance of hearing preservation remains heavily debated. Given the patient's young age, the goal of hearing preservation and the tumor size/extension into the CPA, surgery was decided through a right retrosigmoid transmeatal approach for tumor resection with intraoperative brain auditory evoked responses monitoring. For hearing preservation, we emphasize few important dissection techniques: tumor debulking from the top first to avoid early manipulation of the cochlear nerve at the bottom of the tumor, sharp dissection from medial to lateral off the vestibular nerve which is kept intact as a tension band to minimize cochlear nerve manipulations, and limit the drilling of the posterolateral wall of the internal auditory canal (IAC) medial to the labyrinth and endolymphatic apparatus. Postoperatively, the patient was discharged home within 2 days, with imaging showing a gross total resection. Follow-up audiogram shows unchanged pure tone thresholds. The link to the Video can be found at: https://youtu.be/Z5ftkpJN5k8 .

Mobilization of the Anterior Inferior Cerebellar Artery When Firmly Adherent to the Petrous Dura Mater—A Technical Nuance in Retromastoid Transmeatal Vestibular Schwannoma Surgery: 3-Dimensional Operative Video

The anterior inferior cerebellar artery (AICA) usually runs loosely within the cerebellopontine cistern; in rare cases, however, it is firmly adherent to the petrous dura mater.1,2 Recognizing this variation is particularly important in vestibular schwannoma surgery via the retrosigmoid transmeatal approach to prevent the high morbidity associated with vascular injury. This video demonstrates a surgical technique to effectively mobilize the AICA when firmly adherent to the petrous dura mater. A 39-year-old man presented with a history of progressive right-sided hearing loss without facial weakness or other associated symptoms3. Magnetic resonance imaging (MRI) demonstrated an intracanalicular lesion, suggestive of vestibular schwannoma. During follow-up, audiometry confirmed a further slight deterioration of hearing and repeated MRI demonstrated tumor growth (T2 according to Hannover classification). Since the patient opted against radiosurgery, a retrosigmoid transmeatal approach under continuous intraoperative monitoring was performed in supine position. Following drainage of cerebrospinal fluid and exposure of the cerebellopontine cistern, the AICA was found to be firmly adherent to the petrous dura mater. Both structures were elevated conjointly and displaced medially for safe drilling of the inner auditory canal, sufficient exposure, and complete excision of the vestibular schwannoma. The patient had an excellent recovery, hearing and facial function were preserved, and no secondary neurological deficits noted.The patient consented to publication of this anonymized video.

Retrosigmoid Transmeatal Endoscope-Assisted Approach in Semi-Sitting Position for Resection of Vestibular Schwannoma: 2-D operative Video.

We present a case of a mid-sized vestibular schwannoma (T3b according to the Hannover classification) that was resected through a retrosigmoid transmeatal approach in semi-sitting position under endoscopic assistance. The patient is a 52-year-old male with acute loss of functional hearing on the right side. Audiometry confirmed a loss of up to 60 dB and lost speech discrimination, there were no associated symptoms such as tinnitus or vertigo. This 2D video demonstrates positioning, OR set-up, anatomical and surgical nuances of the skull base approach and the operative technique for microdissection of the tumor from the critical neurovascular structures, especially the facial and cochlear nerves. A gross total resection was achieved and the patient discharged home after four days with unaltered function of the facial nerve (HB I). At one year follow up there was no indication of residual or recurrence.In summary, the retrosigmoid transmeatal approach is an important and powerful tool in the armamentarium for the microsurgical management of all kinds of vestibular schwannomas. Provided the necessary anesthesiological precautions and intraoperative procedures the semi-sitting position is safe and effective. If needed, the approach can be complemented by the use of an endoscope for visualization of the distal internal auditory canal. The link to the video can be found at: https://youtu.be/pPKT4_5nIn0 .

Internal Auditory Canal Reconstruction After Vestibular Schwannomas Removal Through Retrosigmoid-Transmeatal Approach

Objectives: To present a technique of internal auditory canal (IAC) reconstruction using a pediculated dural flap, after removal of vestibular schwannomas through the retrosigmoid craniotomy. Methods: From a series of 213 patients with vestibular schwannomas operated between January 2008 and March 2016 through the retrosigmoid-transmeatal approach, 183 underwent reconstruction of the internal auditory canal with a pediculated dural flap. The IAC was drilled towards the fundus preserving the labyrinthine structures. The dura mater over the IAC was dissected from the bone, remaining pediculated at the entrance of the jugular foramen. This dural flap was used to cover the cranial nerves inside the IAC after tumor removal. Opened mastoid cells and the IAC were closed with muscle or fat grafts and fibrin glue. Results: Reconstruction of the IAC using the described technique was possible in in 183 cases. Fifteen patients (6.8%) developed postoperative cerebrospinal fluid (CSF) leakage and seven patients required reoperation (3.2%) to close the fistulae. Postoperative magnetic resonance imaging (MRI) examinations showed the presence of CSF within the IAC around the preserved cranial nerves. Conclusions: This technique of IAC reconstruction after surgical resection of vestibular schwannomas may avoid scar and adhesion of muscle or fat tissue with preserved cranial nerves, allowing CSF enter inside the IAC. It may help to identify tumor remnants and/or recurrences in postoperative MRI examinations. Comparative studies are needed to evaluate if this technique improves postoperative hearing and facial nerve outcomes.

Estudo da Abertura Externa do Aqueduto Vestibular como Referência na Preservação do labirinto pelo acesso suboccipital retrossigmóide transmeatal

A abertura externa do aqueduto vestibular foi avaliada como uma referência para ajudar na preservação do labirinto por meio do acesso suboccipital retrossigmóideo transmeatal. Foram estudados ossos temporais, segmentos cefálicos, pacientes portadores de neurinomas do acústico e exames por tomografia computadorizada dos ossos temporais. As correlações existentes entre a abertura externa do aqueduto vestibular, poro acústico interno e crista transversa foram observadas, e realizadas medidas entre essas estruturas. Dissecações foram efetuadas nas partes anatômicas para a exposição da abertura externa do aqueduto vestibular junto à saída do saco endolinfático. A parede posterior do meato acústico interno foi aberta, sem atingir, porém, a abertura externa do aqueduto vestibular, que foi usada como referência para o limite lateral da brocagem. Finalmente, o aqueduto vestibular, a cruz commune e o canal semicircular posterior foram abertos para certificar-se de que eles não haviam sido lesados anteriormente, e para comprovar que ainda existia um limite ósseo entre a extremidade lateral do meato acústico interno e o labirinto. A mesma referência foi utilizada em 24 pacientes portadores de neurinomas do acústico, com o propósito de preservar as partes óssea e membranosa do labirinto, e foi estudada por tomografia computadorizada dos ossos temporais. Existia sempre uma correlação entre a abertura externa do aqueduto vestibular, a extremidade lateral do meato t o labirinto. A distância entre o poro acústico interno e a abertura externa do aqueduto vestibular nunca foi menor que a distância entre esse mesmo poro e a crista transversa. A abertura externa do aqueduto vestibular estava, em geral, lateral à projeção perpendicular da extremidade meatal lateral na superfície petrosa posterior, e, quando sob linha direta da visão, fornecia um ângulo apropriado para que pudessem ser evitadas lesões na porção mais póstero-medial do labirinto. Se a parede posterior do meato não fosse brocada até a abertura externa do aqueduto vestibular, o labirinto poderia ser preservado. Os resultados dos casos cirúrgicos mostraram que o labirinto pôde ser mantido intacto em todos os pacientes, e que os tumores foram completamente removidos. Por meio de exames de tomografia computadorizada dos ossos temporais pode-se avaliar o grau de afastamento do hemisfério cerebelar, necessário para a obtenção de um ângulo seguro de exposição da parede meatal posterior, e a extensão dessa parede que pode ser aberta sem causar danos ao labirinto. O estudo anátomo-topográfico, as observações tomográficas e os resultados obtidos na presente casuística comprovam que a abertura externa do aqueduto vestibular pode auxiliar na preservação do labirinto durante a brocagem da parede posterior do meato acústico interno, pelo acesso suboccipital retrossigmóideo.

Facial Nerve Function and Quality of Resection in Large and Giant Vestibular Schwannomas Surgery Operated By Retrosigmoid Transmeatal Approach in Semi-sitting Position with Intraoperative Facial Nerve Monitoring.

Large and giant vestibular schwannomas pose a real problem in their management. The preservation of facial nerve function may limit tumor resection despite the use of intraoperative monitoring of the facial nerve. In Algeria, vestibular schwannomas represent 5% of all intracranial tumors operated on, 80.5% of which are large or giant. From January 2010 to December 2015, 151 large and giant vestibular schwannomas were operated in our department. Tumor diameter was between 30 and 60mm. The most common presenting symptom was hearing loss, which was observed in 41.66% of all our patients. All patients were operated in the semi-sitting position with opening of the posterior wall of the internal auditory canal and under continuous intraoperative facial nerve function monitoring. Tumor resection was total in 126 patients. Anatomic preservation of the facial nerve was the reason for nontotal resection in 25 patients. The facial nerve was anatomically preserved in 149 patients. Two years after surgery, the facial nerve function was grade I-II House-Brackmann (H-B) score in 124 cases (82%),grade III-IV H-B score in 21 cases (14%), and grade V-VI H-B score in 06 cases (04%). The status and the improvement of postoperative facial nerve function depend on 4 factors: anatomic preservation of nerve,stimulation threshold, cystic form, and the presence of train activity. The development of anesthesia techniques and microsurgery and the systematic use of intraoperative monitoring of the facial nerve have allowed us to move from a life preservation era to another era of preservation of function.

Endoscopic assistance in retrosigmoid transmeatal approach to intracanalicular vestibular schwannomas – An alternative for middle fossa approach. Technical note

BackgroundComplete surgical removal of intracanalicular vestibular schwannomas with nerve VII and VIII sparing and without worsening patient's status is challenging. Also the choice of an optimal surgical technique, which is usually limited to selection between retrosigmoid transmeatal (RT) and middle fossa (MF) approach, can be a challenge. Although many previous studies documented superiority of RT to MF approach and vice versa, still no consensus has been reached regarding an optimal approach to intracanalicular vestibular schwannomas. In this technical note, we present RT approach with an endoscopic assistance and highlight its advantages over MF approach in surgical management of pure intracanalicular vestibular schwannomas. MethodRT approach with an endoscopic assistance is presented as an optimal surgical treatment for intracanalicular vestibular schwannomas, and its advantages are compared to those offered by MF approach. ResultsUnder an endoscopic guidance, we found a residual tumor in the fundus of the inner acoustic canal and performed its gross total resection. ConclusionsRT approach is an excellent technique suitable for safe radical surgical treatment of T1 vestibular schwannomas; this technique is associated with lower morbidity risk than MF approach.

Surgery for sporadic vestibular schwannoma. Part I: General outcome and risk of tumor recurrence

BackgroundVestibular schwannomas are slow growing, benign tumors. There are three possible management options: surgery, radiation treatment or active surveillance. The aim of this study was to assess the general outcome and risk of tumor recurrence. Materials and methodsThe study included 220 consecutive patients (134 women, 86 men; the age ranged from 18 to 74) operated with the retrosigmoid transmeatal approach. The largest extrameatal diameter of the tumor ranged from 8 to 72mm (mean 30mm). According to the Samii grading scale, the tumors were classified as follows: T2–12 (6%), T3–51 (23%) and T4–157 (71%). Gross total resection was performed in 217 patients and neartotal in 3. ResultsTwo hundred and eighteen (99.1%) patients were discharged home in a satisfactory neurological condition (GR or MD in GOS). One (0.5%) patient died due to brainstem infarction. One (0.5%) patient had unchanged severe cerebellar syndrome in comparison to the preoperative period (SD in GOS). In long-term follow-up, one patient went blind within a few months after surgery. Including the results of further neurosurgical procedures for CSF leak, shunt implantation, tumor regrowth and facial nerve reanimation, 98.6% of the patients were fully independent but with different neurological deficits. Tumor recurrence was observed in 5 (2.3%) patients during the follow-up period (mean term: 6.4 years). The average time to recurrence diagnosis was 8.8 years. All those patients were operated on again without any adjuvant therapy and there was no further re-growth at mean follow-up of 5.2 years. ConclusionsComplete removal of VS is usually curative and poses very low risks of severe disability (if audio-facial sequels are not included), mortality and long-term recurrence. For recurrent tumors, carefully tailored revision surgery without irradiation offers a high efficacy with low risk of complications.

Vestibular schwannomas: Surgical treatment of 67 cases in 10 years

Vestibular Schwannomas (VS) are benign intracranial tumors, for which their current management is a matter of debate, although microsurgical treatment remains the mode of choice in the majority of cases. To describe the surgical outcome of patients operated on for a VS in a Chilean Public Hospital. A series of 67 patients treated surgically between 2002 and 2012, in the Institute of Neurosurgery Asenjo is presented. Sixty-five cases (97%) corresponded to Koos III and IV tumors, of which 52% were large (3-4 cm) or Giant (>4 cm). Forty-one cases were operated on using a retrosigmoid transmeatalapproach (61%). Total resection was achieved in 97% of the cases and subtotal in the remaining 3%. A mean six months follow-up showed that good facial function (House-Brackmann I or II) was obtained in 32.7% of the patients, and moderate function (House-Brackmann III or IV) in 42.3%. Cardiopulmonary complications were the most frequent (28%), and mortality was 1.5%. The VS are tumors that can cause significant neurological deficit in advanced stages, despite their benign nature. Surgical treatment is very complex, and must be performed by specialized teams to ensure optimal functional results.

Fat graft-assisted internal auditory canal closure after retrosigmoid transmeatal resection of acoustic neuroma: Technique for prevention of cerebrospinal fluid leakage

The retrosigmoid transmeatal approach remains an important strategy in the surgical management of acoustic neuromas. Gross total resection of acoustic neuromas requires removal of tumor within the cerebellopontine angle as well as tumor involving the internal auditory canal (IAC). Drilling into the petrous bone of the IAC can expose petrous air cells, which can potentially result in a fistulous tract to the nasopharynx manifesting as cerebrospinal fluid (CSF) rhinorrhea. We describe our method of IAC closure using autologous fat graft and assessed the rates of postoperative CSF leakage. We performed a retrospective study of 24 consecutive patients who underwent retrosigmoid transmeatal resection of acoustic neuroma who underwent our method of fat graft-assisted IAC closure. We assessed rates of postoperative CSF leak (incisional leak, rhinorrhea, or otorrhea), pseudomeningocele formation, and occurrence of meningitis. Twenty-four patients (10 males, 14 females) with a mean age of 47years (range 18–84) underwent fat graft-assisted IAC closure. No lumbar drains were used postoperatively. There were no instances of postoperative CSF leak (incisional leak, rhinorrhea, or otorrhea), pseudomeningocele formation, or occurrence of meningitis. There were no graft site complications. Our results demonstrate that autologous fat grafts provide a safe and effective method of IAC defect closure to prevent postoperative CSF leakage after acoustic tumor removal via a retrosigmoid transmeatal approach. The surgical technique and operative nuances are described.

Does attempt at hearing preservation microsurgery of vestibular schwannoma affect postoperative tinnitus?

Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery via the retrosigmoid-transmeatal approach with special reference to the postoperative tinnitus outcome. Material and Methods. A prospective study was performed in 89 consecutive patients with unilateral vestibular schwannoma indicated for microsurgery. Patient and tumor related parameters, pre- and postoperative hearing level, intraoperative findings, and hearing and tinnitus handicap inventory scores were analyzed. Results. Cochlear nerve integrity was achieved in 44% corresponding to preservation of preoperatively serviceable hearing in 47% and useful hearing in 21%. Main prognostic factors of hearing preservation were grade/size of tumor, preoperative hearing level, intraoperative neuromonitoring, tumor consistency, and adhesion to neurovascular structures. Microsurgery led to elimination of tinnitus in 66% but also new-onset of the symptom in 14% of cases. Preservation of useful hearing and neurectomy of the eighth cranial nerve were main prognostic factors of tinnitus elimination. Preservation of cochlear nerve but loss of preoperative hearing emerged as the main factor for tinnitus persistence and new onset tinnitus. Decrease of THI scores was observed postoperatively. Conclusions. Our results underscore the importance of proper pre- and intraoperative decision making about attempt at hearing preservation versus potential for tinnitus elimination/risk of new onset of tinnitus.

Protocol for Auditory Brainstem Implants in Children

Objectives: Auditory brainstem implants (ABIs) have been implanted in 64 children with no permanent major complications. We detail the protocol for ABI patient selection, ABI surgery and intra-operative monitoring, and device fitting and rehabilitation with children. Methods: Sixty-four children received the ABI between 2000 and 2013. The follow-up ranged from 6 months to 8 years. A protocol is presented for acoustic and electrophysiological assessment of ABI candidacy. A retrosigmoid-transmeatal approach was used in the Neurofibromatosis type 2 (NF2) and a retrosigmoid approach in the nontumor children. Tests for assessing auditory and cognitive development and rehabilitation are recommended. Results: All children, except NF2 subjects, scored 0 before ABI implantation on all tests, even the 31 children previously fitted with a cochlear implant. Perceptual outcomes showed statistically significant improvements over time. At the last follow-up no significant postoperative complications were observed. Conclusions: ABIs have been shown to be beneficial for children who cannot use a cochlear implant. However, implanting an ABI in a child requires special care and expertise and should only be undertaken by an experienced pediatric implant team. This paper presents a comprehensive protocol for application of ABIs in children.