Long-term hearing prognosis after vestibular schwannoma surgery with retrolabyrinthine approach.

PURPOSE: The retrolabyrinthine approach is a surgical method designed to preserve hearing after surgery. When paired with intraoperative monitoring and an endoscope, this approach has demonstrated high rates of postoperative hearing preservation. However, the long-term prognosis of hearing preservation after utilizing this approach for vestibular schwannomas remains unexplored. This study aimed to examine the long-term outcomes of preserved hearing, providing insights into the suitability of the retrolabyrinthine approach for hearing preservation surgery. METHODS: This study included 34 patients with preserved hearing after vestibular schwannoma surgery using the retrolabyrinthine approach at a single center. Long-term hearing prognosis and requirement for additional interventions were retrospectively examined. RESULTS: Immediate after post-operative hearing preservation rate was 71.7%. Among the 34 patients with preserved hearing post-vestibular schwannoma surgery, four (11.8%) required additional interventions. Other patients experienced a gradual deterioration in their hearing status, with an approximate 10 dB decline during the 5-year follow-up; however, a serviceable hearing level persisted long after the surgery in these individuals. CONCLUSIONS: This study indicated the rationale for the retrolabyrinthine approach as a hearing preservation surgery for vestibular schwannomas, emphasizing its long-term hearing prognosis.

Vestibular Schwannoma Surgery with Endoscope-Assisted Retrolabyrinthine Approach under Modified Reinforced Continuous Intraoperative Monitoring for Hearing Preservation: Experience of 33 Cases in a Single Center.

Surgery for vestibular schwannoma includes various techniques such as the middle cranial fossa, suboccipital, translabyrinthine, and retrolabyrinthine approaches. The retrolabyrinthine approach does not impair the labyrinth and allows postoperative hearing preservation. Previously, we reported an endoscope-assisted retrolabyrinthine approach under reinforced continuous intraoperative monitoring for preservation of hearing and facial nerve function. However, the hearing preservation rate was relatively low in patients with long-wave V latency in the auditory brainstem response or poor otoacoustic emission response under this approach. Thus, the hearing preservation rate in such patients remains to be improved. To overcome this limitation, we modified the previous approach. In 26 of the 33 consecutive cases (79%) over the last three years, preservation of hearing equivalent to that before surgery or improved hearing was achieved. Postoperative deafness was observed in only two of the 33 cases (6%). According to previous reports, the rate of hearing preservation using the retrolabyrinthine approach is approximately 30-50%. Therefore, we have achieved a higher hearing preservation rate than that previously reported using the endoscopy-assisted retrolabyrinthine approach under reinforced continuous intraoperative monitoring. These improvements in our department are considered to be helpful for hearing preservation.

Extended Retrolabyrinthine Approach: Results of Hearing Preservation Surgery Using a New System for Continuous Near Real-time Neuromonitoring in Patients With Growing Vestibular Schwannomas.

OBJECTIVE: To report hearing preservation results after retrolabyrinthine vestibular schwannoma surgery, using a new system for continuous near real-time monitoring of cochlear nerve function. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center, University Hospital. PATIENTS: Thirty-one consecutive patients with growing vestibular schwannomas and opting for hearing preservation surgery. INTERVENTIONS: Tumor removal by a modified, extended retrolabyrinthine approach, using a new system for continuous near real-time monitoring of cochlear nerve function. MAIN OUTCOME MEASURES: Pure-tone average and speech discrimination (SD) 1-year postoperative. Preservation of word recognition score class. Preservation of serviceable hearing (SD>50%). RESULTS: Any hearing was preserved in 83 and 69% had preserved word recognition score class or better. Serviceable hearing was preserved in 77%. SD was unchanged in 48%, improved in 21%, and poorer in 31%. Of 18 patients with potential for improvement (SD 90% or worse preoperatively), 33% improved (SD increase 10% or more). CONCLUSION: The hearing preservation rate is favorable using the modified, extended retrolabyrinthine approach and a new system for continuous near real-time monitoring of cochlear nerve function for removal of growing vestibular schwannomas, as 77% preserved serviceable hearing 1 year after surgery. Hearing improved after surgery in 33%. Using the new neuromonitoring system, serviceable hearing preservation rate improved from 53 to 77% at our center.

Intraoperative Facial Nerve Monitoring Revealed the Origin of Rapidly Progressing Schwannoma in the Cerebellopontine Angle: A Case of Large Intermediate Nerve Schwannoma.

Schwannoma arising from the intermediate nerve is very rare, with only a few cases reported in the literature. Here, we report a rare case of a rapidly growing schwannoma that originated from the intermediate nerve in a 17-year-old woman. We performed tumor resection using the translabyrinthine approach with continuous intraoperative monitoring, in which the facial nerve root was used to evoke muscle action potential. The monitoring revealed the tumor origin and enabled complete surgical resection with the preservation of facial nerve motor function. The facial nerve root evoked muscle action potential-based continuous monitoring revealed the origin of the rare intermediate nerve schwannoma. Appropriate surgery using this monitoring system could spare facial nerve function even in this rare case and retain the patient's quality of life.

Intraoperative Auditory System Monitoring.

A new electrophysiological system for intraoperative, continuous, near-real time monitoring of cochlear nerve function through acoustic stimulation in the ear canal and recording of the evoked dorsal cochlear nucleus potentials (DNAPs) by a specially designed DNAP electrode placed directly on the brainstem is described. The system is denominated "(cerebellopontine angle) CPA Master" and is designed for hearing preservation surgery in the cerebello-pontine angle, through the retro-sigmoid or the retro-labyrinthine approach. As an additional novelty within the field, the system allows intraoperative mapping and thus precise localization of the cochlear nerve in its entire trajectory from the brainstem to the fundus of the internal auditory canal, which is a major advance in relation to atraumatic dissection of the nerve. The system can be used for surgery of all types of CPA tumors, for example, vestibular schwannomas, meningiomas and epidermoid cysts, but also for vestibular nerve section and vascular decompression. The system also allows evaluation of the electrical functionality of an anatomically intact cochlear nerve in translabyrinthine surgery, thus predicting the benefit of optional cochlear implantation.

Repeated Attacks of Dizziness Caused by a Rare Mitochondrial Encephalomyopathy.

Cases of dizziness caused by multiple sclerosis are commonly reported, but those caused by mitochondrial encephalomyopathy have been rarely reported. Particularly, the description of eye nystagmography (ENG) using caloric and optokinetic nystagmus tests has not been reported to date. We encountered the case of a 40-year-old woman with mitochondrial encephalomyopathy who visited us with the chief complaint of dizziness. At first, we considered multiple sclerosis based on the magnetic resonance imaging (MRI) findings and dizziness. Repeated attacks of dizziness and serum lactic acid levels suggested mitochondrial encephalomyopathy. A muscle biopsy confirmed the diagnosis. ENG findings suggested central vestibular disorder of the cerebellum and brainstem. This case suggests that we should not rule out the differential diagnosis of a very rare mitochondrial encephalomyopathy in patients who experience dizziness with MRI findings indicative of multiple sclerosis.

Sporadic Endolymphatic Sac Tumor-A Very Rare Cause of Hearing Loss, Tinnitus, and Dizziness.

Sporadic endolymphatic sac tumor is a very rare neoplasm. It is low malignant, locally destructive and expansive, but non-metastasizing. The tumor is very rare in the sporadic form, but more often associated with Von Hippel-Lindau disease. A 65-year old man with left sided tinnitus and hearing loss for several months. Audiometry showed an asymmetrical sensory neural hearing loss on the left side up to 60 dB. The speech discrimination score was 46% and stapedial reflexes were absent. Several years earlier, he had suffered from periods of dizziness. Magnetic resonance imaging (MRI) showed a destructive and locally invasive tumor in the peripheral vestibular system expanding into the cerebellopontine angle. Paraganglioma and von Hippel-Lindau`s disease were excluded. Vestibular examination showed no function of vestibular organ left side. The tumor was resected radically by translabyrintine approach. Per-operative freeze-microscopy showed inflammation tissue, whereas subsequent microscopy showed papillary-cystic endolymphatic sac tumor. Endolymphatic sac tumor is a rare neoplasm. The tumor may present with asymmetrically sensory neural hearing loss with or without tinnitus, dizziness and facial nerve paresis. An MRI scan is the appropriate diagnostic tool final dianosis is made by the post-operative histo-pathology. Dizziness can be the first sign of a tumor in this area.

How minimally invasive vestibular neurotomy for incapacitating Meniere's disease improves dizziness and anxiety.

CONCLUSION: Patients with incapacitating Meniere Disease (MD) suffer in their daily lives and activities because of the dizziness and anxiety induced by MD. Minimally Invasive Vestibular Neurotomy (MIVN) is a safe and effective surgical treatment for these individuals, and improved their dizziness and anxiety. OBJECTIVES: This study aimed to assess the state of dizziness and anxiety of patients with incapacitating MD and its improvement through MIVN. METHOD: A total of 118 patients with incapacitating MD who underwent MIVN in France and Japan were evaluated. The DHI (Dizziness Handicap Inventory), SAST (Short Anxiety Screening Test), and STAI (State Trait Anxiety Index) questionnaires were used to evaluate disequilibrium and anxiety. RESULTS: The MIVN method appears safe and effective for patients with incapacitating MD. Pre-operative assessment results by DHI and SAST were significantly related to each other, and were influenced by lifestyle and profession. This prospective study showed that MIVN improved dizziness and anxiety in these patients.

Objective and Subjective Outcome of a New Transcutaneous Bone Conduction Hearing Device: Half-year Follow-up of the First 12 Nordic Implantations.

OBJECTIVE: To examine the objective and subjective outcome of a new transcutaneous bone conduction hearing device. STUDY DESIGN: Prospective, consecutive case series. PATIENTS: Twelve patients were implanted. Eight patients had a conductive/mixed (con/mix) hearing loss. Four had single sided deafness. MAIN OUTCOME MEASURES: At half-year follow-up, aided and unaided sound field hearing was evaluated by 1) warble tone thresholds, 2) pure-tone average (PTA4), 3) speech discrimination score (SDS) in quiet, and 4) speech reception threshold 50% at 70 dB SPL noise level (SRT50%). Subjective outcome was evaluated by three questionnaires: 1) International Outcome Inventory for Hearing Aids, 2) Speech, Spatial and Qualities of Hearing Scale 12, and 3) a questionnaire on frequency and duration of use. RESULTS: No major complications occurred. The mean aided PTA4 was lowered by 23dB. SDS was increased by 40% at 50dB, by 34% at 65dB, and by 12% at 80 dB SPL. SRT50% in noise improved 5.2 dB. 58% of the patients used the device daily and 83% at least 5 days a week. 50% used the device ≥ 8 hours and 75% ≥ 4  hours a day. Mean International Outcome Inventory for Hearing Aids score was 3.7, corresponding to beneficial outcome. In Speech, Spatial and Qualities of Hearing Scale 12, "quality of hearing" scored especially high. The con/mix hearing loss group showed larger benefit especially in SDS, SRT50% in noise and the subjective evaluations, whereas frequency and duration of use were similar. CONCLUSION: This study on the first 12 Nordic patients implanted with a new transcutaneous bone conduction hearing device demonstrates significant objective, as well as subjective hearing benefit. Patient satisfaction was high, as was the frequency of use.

Improved preservation of function during acoustic neuroma surgery.

OBJECT: Restoration of cranial nerve functions during acoustic neuroma (AN) surgery is crucial for good outcome. The effects of minimizing the injury period and maximizing the recuperation period were investigated in 89 patients who consecutively underwent retrosigmoid unilateral AN surgery. METHODS: Cochlear nerve and facial nerve functions were evaluated during AN surgery by use of continuous auditory evoked dorsal cochlear nucleus action potential monitoring and facial nerve root exit zone-elicited compound muscle action potential monitoring, respectively. Factors affecting preservation of function at the same (preoperative) grade were analyzed. RESULTS: A total of 23 patients underwent standard treatment and investigation of the monitoring threshold for preservation of function; another 66 patients underwent extended recuperation treatment and assessment of its effect on recovery of nerve function. Both types of final action potential monitoring response and extended recuperation treatment were associated with preservation of function at the same grade. CONCLUSIONS: Preservation of function was significantly better for patients who received extended recuperation treatment.

Routes, dynamics, and correlates of cochlear inflammation in terminal and recovering experimental meningitis.

OBJECTIVES/HYPOTHESIS: To examine the routes, dynamics and correlates of cochlear inflammation in meningitis to provide information on the pathogenesis of the associated hearing loss and indications for rational pharmacotherapeutical intervention. STUDY DESIGN: A well-established rat model of Streptococcus pneumoniae meningitis was employed. METHODS: Eight rats were inoculated intrathecally and not treated, whereas 26 were inoculated and treated with ceftriaxone. Six rats were sham-inoculated, making a total of 40 rats. The rats were sacrificed when reaching terminal illness or after 7 days, followed by light microscopy. Routes of cochlear inflammatory infiltration were examined. The volume fraction of inflammatory infiltration was estimated and correlated to bacterial and leukocyte counts in cerebrospinal fluid (CSF) and blood. RESULTS: The perilymphatic space was infiltrated with inflammatory cells via cochlear aqueduct, whereas the endolymphatic space was infiltrated from the spiral ligament. Rosenthal's canal was infiltrated through osseous spiral lamina canaliculi. In the untreated group, the degree of inflammation correlated with time of death, whereas antibiotic treatment reversed this development. Perilymphatic inflammation correlated significantly with the CSF leukocyte count, whereas endolymphatic inflammation correlated with spiral ligament inflammation. CONCLUSIONS: Meningogenic inflammation of the rat cochlea occurs via the cochlear aqueduct and the spiral ligament capillary bed. The spiral ganglion is infiltrated through the osseous spiral lamina. The degree of inflammation correlates positively with time of death in untreated meningitis, whereas antibiotic treatment leads to subsiding infiltration during recovery.

[Petrous cholesteatoma: clinical features and surgical outcome].

In this study we analyzed the clinical features and surgical treatment of petrous cholesteatoma in 9 patients (9 ears) who underwent surgery at the Jikei University Hospital. Most patients initially experienced hearing loss, then facial nerve palsy or otorrhea. Congenital cholesteatoma was diagnosed in four patients, acquired cholesteatoma in one patient, and postoperative recurrence in three patients. The proportion of cases of congenital cholesteatomas was higher than in previous reports. The area of the cholesteatoma was classified according to Dr. Sanna cases and the supralabyrinthine type in two cases. Hearing preservation surgery was performed in four patients via the middle cranial fossa approach or by partial labyrinthectomy, and the results seemed satisfactory. These results suggested that hearing preservation surgery should be adopted in every case.

Endoscope-assisted surgery via the middle cranial fossa approach for a petrous cholesteatoma.

OBJECTIVE: Surgical approaches to petrous cholesteatomas are the translabyrinthine-transcochlear approach, partial labyrinthectomy, and the middle cranial fossa approach. Selection of surgical approach is determined by region of cholesteatoma in the petrous bone as well as preoperative status of hearing and facial nerve function. The middle cranial fossa approach is the best approach for patient having good preoperative hearing and facial nerve function. However, application of this approach is limited for patients having relatively small petrous cholesteatomas, and sometimes difficult for patients in whom inner ear function is preserved but a cholesteatoma surrounds whole cochlea and extends to lower part of the labyrinth. In such case, we performed endoscope-assisted surgery via the middle cranial fossa approach to preserve cochlear and its function. METHODS: 30 degrees and 70 degrees rigid endoscopes were used for the operation via the middle cranial fossa. RESULTS: The inferior surface of the cochlea and the region around the internal carotid artery could be well visualized by use of endoscopy, and we succeeded in removal of petrous cholesteatoma surrounding the cochlea completely with preserving preoperative hearing. CONCLUSION: Endoscope-assisted surgical technique that allowed safe and complete removal of a cholesteatoma extended inferior surface of coclear and around carotid artery in the petrous.

Neuro-otologic surgery through minimally invasive retrosigmoid approach: endoscope assisted microvascular decompression, vestibular neurotomy, and tumor removal.

OBJECTIVES: The objective of this study was to describe and evaluate the efficacy of the endoscope assisted minimally invasive retrosigmoid approach. STUDY DESIGN: Retrospective study and literature review. METHODS: From December 1993 to December 2004, a total of 1,177 cases of endoscope assisted minimally invasive retrosigmoid approach were performed at the Otorhinolaryngology unit of Hôpital Nord in Marseille. By using this approach, we performed microvascular decompression for hemifacial spasm and trigeminal neuralgia, vestibular neurotomy for refractory Ménière's disease with repeated attacks of dizziness, and tumor removal of acoustic neurinoma. We examined the results and postoperative complications. RESULTS: All the results were positive, and we did not experience any mortal complications. The most common complication was cerebrospinal fluid leakage, encountered in 42 (3.6%) cases. CONCLUSIONS: We believe that the combination of an endoscope and microscope that provides accurate information with low invasion is becoming indispensable for these types of operations, which are in the category of functional surgery. We report the merits and significance of the approach of combining the endoscope and microscope and discuss the operational technique to perform a minimally invasive surgery as an oto-neurosurgeon.

Enhancement of cyclophosphamide sensitivity in squamous cell carcinoma transfected with cytochrome P-450 2B1.

PURPOSE: Cyclophosphamide (CPA) has been shown to be quite effective and safe in the treatment of leukemia, but it had shown almost no efficacy in the treatment of solid tumors such as head and neck cancers. The purpose of this study was to determine whether head and neck squamous cell carcinomas can be made more sensitive to the cytotoxic effect of CPA by shifting the balance from the degradative to the activation pathway. MATERIALS AND METHODS: Human SCC-25 squamous carcinoma cells were transfected by adenoviral vector containing P-450 2B1 gene and were identified for P-450 2B1 expression by Northern blot analysis. In vitro cytotoxic assay after CPA exposure was performed using these cells. Human KB oral base squamous cell carcinoma cells were injected subcutaneously to the backs of nude mice. Then Ad.CMV-P-450 2B1 was injected intratumorally. At 48 hours after the injection of Ad.CMV-P-450 2B1, CPA was injected into the peritoneal cavity of the animals and the volume of the tumor was determined with the passage of time. All the animal procedures were performed under the guidance of the committee in our animal care facility. RESULTS: The in vitro experiments found that transduction of the P-450 2B1 gene caused a nearly 30-fold increase in the sensitivity of the host cell line to CPA on the basis of the 50% inhibitory concentration. The in vivo experiments, which were conducted in nude mice, found that the combination of P-450 2B1 gene transduction and administration of CPA showed an inhibitory effect on tumor growth. CONCLUSIONS: The P-450 2B1- cyclophosphamide system may be useful approach for gene therapy of squamous cell carcinomas of head and neck.

[Congenital middle ear cholesteatoma: experience in 48 cases].

We studied 48 patients (48 ears) with congenital cholesteatoma who underwent surgery at our department from 1979 to 2000, and investigated symptoms at initial onset, tympanic membrane findings, cholesteatoma configuration and site, type of surgical procedure, and surgical outcome. Patients were from 2 to 62 years old (mean: 16.7 years), with 60.4% aged 15 years or younger. The symptom at initial onset was hearing loss in most (58.2%). Hearing loss was the main symptom in all with open type cholesteatoma, and most of these patients had normal tympanic membrane findings. The cholesteatoma was located mainly in the superior posterior portion of the tympanic cavity in many patients. The site of involvement was the tympanic cavity in 12 (25.0%), mastoid cavity in 2 (4.2%) and the petrous apex in 1 (2.1%). In many of (31 ears, 64.6%), the cholesteatoma was advanced and extended from the tympanic cavity to the mastoid antrum. For 23 of the 48 ears, treatment was completed in one operation. The remaining 25 ears required staged surgery. Loss of the structure of the upper part of the stapes was seen in 58.3% of patients, so most underwent type IV ossiculoplasty, with types III and I next most common.

Enhancement of cytarabine sensitivity in squamous cell carcinoma cell line transfected with deoxycytidine kinase.

BACKGROUND: Cytarabine is the most effective agent known for the treatment of acute myeloid leukemia. Its antitumor effect is expressed by combining with DNA during replication and then destroying the DNA chain. However, cytarabine has only limited activity against most solid tumors, including squamous cell carcinoma of the head and neck. The reason for this is thought to be that in cell lines of solid tumors the expression of cytidine deaminase, an enzyme that degrades cytarabine, is high, whereas the expression of deoxycytidine kinase (dCK), which phosphorylates cytarabine (a prodrug), is weak. OBJECTIVE: To determine whether head and neck squamous cell carcinomas can be made more sensitive to the cytotoxic effects of cytarabine by shifting the balance from the degradative to the activation pathway. METHODS: Human SCC-25 squamous carcinoma cells were transfected by either retroviral vector or adenoviral vector containing DCK gene and were identified for dCK expression by Northern blot analysis. In vitro cytotoxic assay after cytarabine exposure was performed using these cells. RESULTS: Both retroviral and adenoviral vector-mediated transduction of the dCK complementary DNA resulted in marked sensitization of tongue squamous carcinoma cell lines to the cytotoxic effects of cytarabine in vitro. CONCLUSION: The dCK-cytarabine system may be a useful approach for gene therapy of squamous cell carcinomas of the head and neck.