Samih Charabi

Cystic vestibular schwannoma: surgical outcome.

We investigated the proportion of the cystic form of vestibular schwannoma and assessed the results of surgery in this subtype of the condition. The definition of cystic vestibular schwannomas was based on the following criteria: per-operative identification of cystic components; occurrence of the hypodense/hypointense areas on computed tomography (CT) and/or magnetic resonance (MR); and histological verification of S-100 protein membrane-like structures. In a study of 773 Danish patients with vestibular schwannomas, 44 (5.7 per cent) displayed cystic components. The outcome of surgery on 44 cystic vestibular schwannoma (mean tumour size 39 mm) was evaluated and compared with that for 151 solid grant vestibular schwannoma (mean tumour size 49.8 mm). Per-operatively, we found a substantially higher adherence to different intracranial structures in the solid giant vestibular schwannoma compared with the cystic vestibular (95 per cent vs 70 per cent for brainstem, 91 per cent vs 59 per cent for trigeminal nerve, 85 per cent vs 45 per cent for cranial nerves X and XI, 67 per cent vs 32 per cent for dura). Nevertheless, the preservation of the facial nerve function was much better in patients with solid giant vestibular schwannoma compared with those with cystic vestibular schwannoma (House-Brackmann facial nerve dysfunction grade 6 (one year post-operative): 27 per cent vs 41 per cent, respectively p < 0.04). We conclude that the cystic components in vestibular schwannoma are associated with a less favourable surgical outcome, probably due to the rapid tumour growth and symptoms caused by compression of the posterior fossa structures.

Preliminary results of a new delivery system for gentamicin to the inner ear in patients with Meniere's disease.

Abstract Intratympanic gentamicin therapy has gained some clinical popularity in the treatment of vertigo associated with Meniere’s disease. This therapeutic modality offers some advantages over traditional surgical treatment. The vestibulotoxic effect of gentamicin is well documented, but there is no general agreement about the dose needed to control vertigo attacks without affecting hearing. In the current preliminary study 27 patients with Meniere’s disease refractory to medical management were treated by small doses of gentamicin delivered via microcatheter in the round window niche and administered by an electronic micropump. The patients received a total dose of 0.24–90 mg. The effect on vestibular symptoms resulted in the cessation of vertigo in the 22 patients, control of drop attacks in 4 of 6, and release of aural pressure and fullness in 2 of 4. Significant hearing loss (anacusis) occurred in six patients, slightly related to the flow rate in the pump setting. Different explanations for the loss of hearing are presented. The new delivery system for gentamicin appears to be effective in controlling vertigo, but with an unacceptable negative effect on hearing. The effectiveness and the safety of this new delivery system must be investigated further in controlled studies. However, it opens up the possibility of future novel ways of treating inner ear diseases, such as sudden deafness and tinnitus, as well as for the protection, repair, and regeneration of inner ear sensory cell function in damage due to aging, noise, toxic substances, immune reactions, etc.

Acoustic Neuroma/Vestibular Schwannoma Growth: Past, Present and Future

The growth of vestibular schwannoma (VS) was investigated in a series of 123 patients with 127 tumors in the period 1973 1993. The material was reanalysed and updated 3 years later in 1996. By termination of the first observation period (mean 3.4 years), 94 tumors (74%) exhibited measurable growth, 23 tumors (18%) no measurable growth and 10 tumors (8%) negative growth. By the end of the extended observation period (mean 3.8 years), tumor growth was observed in 104 tumors (82%), no tumor growth in 15 tumors (12%) and negative growth in eight tumors (6%). Several growth patterns were noticed: however, these were not static as the growth patterns of the tumors changed during the extended observation period. Accordingly, the expected growth figures by the end of this century (mean observation period approximately 4 years) will probably be: growth in 111 tumors (87%), no growth in 10 tumors (8%) and negative growth in six tumors (5%). The results indicate that neither the present study nor the previously published studies on tumor growth reflect the natural history of VS, but they only provide information on tumor growth, growth rates and growth patterns during a given observation period.

Vestibular schwannoma growth : The continuing controversy

Objective To investigate the growth of vestibular schwannoma (VS) in a series of 123 patients with 127 tumors allocated to the “wait and scan” group in the period 1973–1999.

Clinical experience with vestibular schwannomas : epidemiology, symptomatology, diagnosis, and surgical results

Abstract The Danish model for vestibular schwannoma (VS) surgery has been influenced by some historical otological events, taking its origin in the fact that the first attempt to remove CPA tumors was performed by an otologist in 1916. In approximately 50 years VS surgery was performed by neurosurgeons in a decentralized model. Highly specialized neuro- and otosurgeons have been included in our team since the early beginning of the centralized Danish model of VS surgery in 1976. Our surgical practice has always been performed on the basis of known and proven knowledge, but we spared no effort to search for innovative procedures. The present paper reflects the experience we have gained in two decades of VS surgery. Our studies on the incidence, symptomatology, diagnosis, expectancy and surgical results are presented.

Histopathologic parameters in the evaluation of T1 squamous cell carcinomas of the oral cavity

Prognostic indicators that could assist in a more precise selection of patients with small oral carcinomas for differentiated therapy would be valuable. A significant fraction of patients with stage I disease have a relatively poor prognosis despite the small size of the tumor, but in general stage I tumors of the oral cavity have a favorable prognosis.

Cystic Vestibular Schwannoma - Clinical and Experimental Studies

The cystic variant of vestibular schwannoma (VS) presents a therapeutic dilemma. Several studies have previously demonstrated that the surgical outcome in this tumour entity is less favourable than that of solid tumours of comparable size. The wait and scan policy has not been recommended for these tumours, as the cystic elements expand, causing displacement of the brainstem and compression of the 4th ventricle, resulting in hydrocephalus. The large tumour size at diagnosis and the cystic contents do not support the role of radiosurgery as a therapeutic option. We have previously published the surgical outcome of 23 cystic VS. The present study includes 44 patients (44 cystic tumours) in a series of 773 tumours (5.7%) who underwent surgery in the period 1976 to 1996. This paper presents the neuroradiological and histological features of the tumours, as well as the results of tumour specimen implantation and surgery in athymic nude mice. Therapeutic options are also discussed.The cystic variant of vestibular schwannoma (VS) presents a therapeutic dilemma. Several studies have previously demonstrated that the surgical outcome in this tumour entity is less favourable than that of solid tumours of comparable size. The wait and scan policy has not been recommended for these tumours, as the cystic elements expand, causing displacement of the brainstem and compression of the 4th ventricle, resulting in hydrocephalus. The large tumour size at diagnosis and the cystic contents do not support the role of radiosurgery as a therapeutic option. We have previously published the surgical outcome of 23 cystic VS. The present study includes 44 patients (44 cystic tumours) in a series of 773 tumours (5.7%) who underwent surgery in the period 1976 to 1996. This paper presents the neuroradiological and histological features of the tumours, as well as the results of tumour specimen implantation and surgery in athymic nude mice. Therapeutic options are also discussed.

Surgical outcome in malignant parotid tumours.

Of 494 parotid gland tumours treated in Copenhagen county (population 600,000 inhabitants) in the period 1986-95, 50 patients (34 males, 16 females) had tumours that were proven to be malignant, making an incidence of 0.62/100,000/year. The patients age ranged from 14 to 87 years, mean 64 years. According to the UICC classification system, 6 tumours (12%) were classified as stage I, 23 (46%) as stage II, 14 (28%) as stage III, and 7 (14%) as stage IV. The material included 41 primary parotid gland tumours, histologically the tumours were verified as mucoepidermoid carcinoma ( n =13), adenocarcinoma ( n =9), squamous cell carcinoma ( n =6), carcinoma ex pleomorph adenoma ( n =3), acinic cell carcinoma ( n =3), adenoid cystic carcinoma ( n =3) and other histological diagnoses ( n =4). Primary malignant lymphoma of the parotid gland was diagnosed in six tumours and the last three tumours were metastatic carcinoma. Four therapeutic modalities were applied: surgery only, surgery+radiation, surgery+chemotherapy, and surgery+chemotherapy+radiation. Surgical radicality was achieved in 76% and radicality was unrelated to tumour histology. Normal or nearly normal facial nerve function (HB1&2) was noted at last follow-up in 60%. Five-year crude survival for all patients was 68%. Survival was not dependent on N-classification. Patients in stage I had a better survival than did patients in stages II, III and IV. No significant difference was observed in 5-year crude survival or in the post-operative facial nerve function between the radically operated patients ( n =38) and patients with residual tumour ( p =0.27, Log-rank test), ( p =0.48, h 2 test).

Thallium chloride 201Tl combined with single photon emission computed tomography (SPECT) in the evaluation of vestibular schwannoma growth

Thallium chloride 201Tl combined with SPECT was performed in a series of 29 patients with neuroradiological evidence of vestibular schwannoma (VS). The relative tumor uptake (U) and relative tumor concentration (C) of the radiotracer 201Tl was determined, and the cerebellum served as a reference. The relative tracer concentration and uptake were correlated to tumor volume determined by gadolinium DTPA enhanced MR, to prediagnostic duration of symptoms, to tumor vascularity expressed by the average number of intratumoral vessels using the endothelial marker CD31, and to the proliferative activity in the tumors expressed by positive staining with the monoclonal antibody MIB-1 for Ki-67. A positive 201TI enhancement was detected in 17 tumors (n = 17). Tumors U and C were statistically unrelated to tumor volume (p = 0.236 and p = 0.439). SPECT demonstrated all tumors > 0.8 cm3, but it had its limitation as a diagnostic modality of small intracanalicular tumors, when compared with gadolinium DTPA enhanced MR. Relating U and C in all tumors (n = 29) and the prospectively registered data on the prediagnostic duration of symptoms, a statistical significance was found (p = 0.012 and p = 0.015). No statistically significant correlation was observed between U and C and the proliferative activity of the tumors expressed by positive staining with the monoclonal antibody MIB-1 for Ki-67 (p = 0.063 and p = 0.086). A statistically significant correlation was noted between C and U in the operated group (n = 12) and tumor vascularity expressed by the average number of the intratumoral vessels (p = 0.003 and p = 0.014). SPECT was found to be superior to MR in determining VS growth potentials as it expresses tumor vascularity, which is essential for tumor growth. It seems that we now have an in vivo functional radiological modality capable of providing data on VS vascularity and determination of growth potential in the individual tumor. A high radioactive tracer uptake in the tumor corresponded to high tumor vascularity, indicating a high growth rate and vice versa.

Round window gentamicin μ-catheter : A new therapeutic tool in Ménière's disease

The vestibulotoxic effect of gentamicin is well documented; however, there is no general agreement on the gentamicin dose needed to control vertigo attacks without affecting the hearing. In the current study, 14 patients with Ménières disease refractory to medical treatment were treated by small doses of gentamicin delivered via a w -catheter, placed into the round window niche. An electronic micropump delivered 10 w l (100 w g)/h. The patients received a total dose of 4-14 mg. The effects on the vestibular symptoms were most encouraging, with cessation of vertigo in 13 of the 14 patients, control of Tumarkin attacks in 4 out of 6 cases and release of aural pressure and fullness in 2 out of 4 cases. According to the recommendations of the Committee on Hearing and Equilibrium, the patients in this material belonged to functional levels 5 and 6. At the last clinical follow-up, five patients were classified as level 1, eight patients as level 2 and one patient as level 3. A significant hearing loss was seen in one patient; however, this was most likely due to the natural development of the disease in this particular case. The results look promising, but must be investigated further in a placebo-controlled study.