M. Yilmaz

An Overview of Hereditary Hearing Loss

Understanding the genetic basis of hearing loss is important because almost 50% of profound hearing loss are caused by genetic factors and more than 120 independent genes have been identified. In this review, after a brief explanation of some genetic terms (allele, heterozygosis, homozygosis, polymorphism, genotype and phenotype), classification of genetic hearing loss (syndromic versus nonsyndromic, and recessive dominant, X-linked and mitochondrial) was performed. Some of the most common syndromes (Usher, Pendred, Jervell and Lange-Nielsen, Waardenburg, branchio-oto-renal, Stickler, Treacher Collins and Alport syndromes, biotinidase deficiency and Norrie disease) causing genetic hearing loss were also explained briefly. The genes involved in hearing loss and genetic heterogeneity were presented.

Lymphatic Metastasis to the Supraretrospinal Recess in Laryngeal Squamous Cell Carcinoma

In order to evaluate lymphatic metastasis to the supraretrospinal recess (SRSR) in laryngeal squamous cell carcinoma (SCC), we separately dissected SRSR lymph nodes and submitted them to pathological examination. Fifty-three lateral neck dissections (LNDs), 2 radical neck dissections (RNDs), and 19 modified RNDs were performed in 49 previously untreated patients with laryngeal SCC. The nodal status of the patients was NO in 29 patients, N1 in 17, and N2 in 3. The neck was pathologically positive in both RNDs (100%), in 7 of 19 modified RNDs (37%), and in 7 of 53 LNDs (13%). No SRSR lymph nodes were positive in any of the dissection materials. No metastasis was found in the SRSR lymph nodes in the N0 necks treated with LND, and none was found even in N1 and N2 necks treated with RND or modified RND. We conclude that the SRSR may be left undissected during treatment of an N.0 neck with LND so that accessory nerve dysfunction can be minimized and operative time can be saved.

Tapia's syndrome following septorhinoplasty.

No surgery is free of complications varying from common minor problems to very unexpected and severe ones. In the case presented here, unilateral paralysis of the muscles of the tongue and ipsilateral vocal cord paralysis due to a lesion of the 10th and 12th cranial nerves occurred following a septorhinoplasty that was performed under endotracheal general anesthesia. This rare entity known as Tapia’s Syndrome is believed to be caused by pressure neuropathy of both nerves due to inflation of the cuff within the larynx. We remind surgeons of this unusual complication that can occur in any surgery under general anesthesia and discuss its diagnosis, treatment method, and the followup results in light of the literature.

Association of the -1438G/A polymorphism of the 5-HT2A receptor gene with obstructive sleep apnea syndrome

Objective: Serotonergic neurons innervating motoneurons increase their firing rates in response to respiratory challenges, and long-term facilitation of respiratory activity in response to hypoxia is serotonin (5-HT) dependent. Polymorphism of the genes which code for 5-HT receptors may affect functions of the serotonergic system, and may be associated with obstructive sleep apnea syndrome (OSAS). The objective in this study was to assess the significance of T102C and –1438G/A polymorphisms of the 5-HT2A receptor gene in OSAS. Methods: Fifty-five patients with OSAS and 102 healthy volun teers were included for genetic analyses of T102C and –1438G/A polymorphisms of the 5-HT2A receptor gene. Results: For the T102C polymorphism, there was no significant difference between the patients and controls and both genders (p > 0.05). For the –1438G/A polymorphism, the A/A and G/A genotypes were overrepresented in the patients and controls, respectively (p = 0.045). In the control group, the genotypes of both genders were not significantly different (p > 0.05). In the patients, the A/A and G/A genotypes were overrepresented in males and females, respectively (p = 0.035). Concerning males, the A/A genotype was overrepresented in patients (p = 0.007). Conclusion: Serotonergic mechanisms appear to be related to OSAS. The T102C polymorphism of the 5-HT2A receptor gene is not associated with OSAS. However, the –1438G/A polymorphism is associated with OSAS occurrence, especially in male patients. This polymorphism may also be associated with different OSAS incidences of both genders.

Bone cement ossiculoplasty: incus to stapes versus malleus to stapes cement bridge.

Objective: In this study, our purpose was to evaluate results of our experience with bone cement repair of ossicular discontinuity between the incus and stapes and between the malleus and stapes. Methods: Medical records of patients who underwent surgery for chronic otitis media between March 2000 and December 2002 were evaluated retrospectively. Fifty-seven patients who underwent bone cement ossiculoplasty and had appropriate follow-up data were included in the study. Bone cement reconstruction of the ossicular chain was performed 1) from incus to stapes (I-S) in the absence of long arm or lenticular process of the incus and 2) from malleus to stapes (M-S) in the absence of the incus. The clinical data of the patients were evaluated by otoscopic examination and audiometry. Results: The graft take rate was 84.1%. I-S procedure was performed in 42 and M-S in 8 patients. Pre- and postoperative PTAs of all patients were compared, which showed a significant improvement in air PTA (p < 0.001) while bone PTA did not change (p > 0.05). In I-S and M-S groups, successful hearing restoration could be achieved in 78.6.1% and 87.5% of the patients, respectively. Hearing results of different aural pathologies (chronic otitis media and conductive hearing loss) and surgeries (tympanotomy and tympanoplasty with or without mastoidectomy) were not significantly different (p > 0.05). Conclusion: Bone cement ossiculoplasty offers cost effective and significant improvement in conductive hearing loss.

Increased micronucleus frequencies in surrogate and target cells from workers exposed to crystalline silica-containing dust.

Mining, crushing, grinding, sandblasting and construction are high-risk activities with regard to crystalline silica exposure, especially in developing countries. Respirable crystalline silica (quartz and cristobalite) inhaled from occupational sources has been reclassified as a human carcinogen in 1997 by the International Agency for Research on Cancer. However, the biological activity of crystalline silica has been found to be variable among different industries, and this has formed the basis for further in vivo/in vitro mechanistic research and epidemiologic studies. This study was conducted for genotoxicity evaluation in a population of workers (e.g. glass industry workers, sandblasters, and stone grinders) mainly exposed to crystalline silica in four different workplaces in Turkey. The micronucleus (MN) assay was applied both in peripheral blood lymphocytes (PBL) as a surrogate tissue and in nasal epithelial cells (NEC) as a target tissue of the respiratory tract. Our study revealed significantly higher MN frequencies in the workers (n = 50) versus the control group (n = 29) (P < 0.001) and indicated a significant effect of occupational exposure on MN induction in both of the tissues. For the NEC target tissue, the difference in MN frequencies between the workers and control group was 3-fold, whereas in peripheral tissue, it was 2-fold. Respirable dust and crystalline silica levels exceeding limit values and mineralogical/elemental dust composition of the dust of at least 70% SiO(2) were used as markers of crystalline silica exposure in each of the workplaces. Moreover, 24% of the current workers were found to have early radiographical changes (profusion category of 1). In conclusion, although the PBL are not primary target cells for respiratory particulate toxicants, an evident increase in MN frequencies in this surrogate tissue was observed, alongside with a significant increase in NEC and may be an indicator of the accumulated genetic damage associated with crystalline silica exposure.

Practical Use of MESNA in Atelectatic Ears and Adhesive Otitis Media

Objective: MESNA is a synthetic sulfur compound that produces mucolysis by disrupting disulfide bonds. This study aimed to address indications and technique of MESNA application in otologic surgery, especially in retraction pockets and adhesive otitis media. Methods: MESNA application was performed in 42 ears of 39 patients. The diagnoses were retraction pockets fixed to incudostapedial joint, stapes or promontorium, and adhesive otitis media in 24 and 17 ears, respectively. Calculations were performed according to 24 ears of 23 patients with follow-up data. Results: One or more of the following surgical interventions were performed: MESNA application alone and ventilation tube insertion, reinforcement or mastoidectomy in addition to MESNA application. Sensorineural hearing loss was not encountered after MESNA application. The operation was successful in 79.2%. Overall revision surgery was needed in 20.8% of the ears. In 71.4% of the ears treated with MESNA alone, revision surgery was needed. Conclusion: In the light of our experience, we advocate the use of MESNA in atelectatic ears, because it makes the operation easy and safe by allowing elevation of the tympanic membrane by its mechanical and chemical actions.

Nasal septal perforation in an adolescent girl with Crohn's disease: a rare extraintestinal manifestation.

Crohns Disease (CD) is a chronic granulomatous inflammatory bowel disease which may also involve the extraintestinal organs such as joints, liver, skin and perianal tissue. Involvement of the aerodigestive tract is quite rare in CD. We report a 16-year-old girl with CD and nasal perforation as an extraintestinal manifestation of the disease.

Evaluation of the Results of Endoscope-Assisted Acoustic Neuroma Surgery through Posterior Fossa Approach

The objective of this study was to evaluate the results of endoscope-assisted acoustic neuroma surgery in posterior fossa approach. Between 1996 and 2002, 60 consecutive patients with acoustic neuroma were operated via the retrosigmoid suboccipital approach. Standard 4-mm sinus endoscopes at different angles were used during the surgeries either for inspection or tumor endoscopic dissection. Clinical parameters and treatment outcome were evaluated retrospectively. Tumor sizes were small, medium and large in 46.6, 45 and 8.3% of the patients, respectively. The hearing preservation rate, which did not correlate with tumor size (p > 0.05), was 24.4%. The need for facial reanimation surgery, which was needed in 5% of patients, was significantly higher in the large tumors than in the small and medium tumors (p < 0.001). Cerebrospinal fluid fistula rate, which was not related to tumor size (p > 0.05), was 13.3%. Tumor recurrence or residual tumor was not encountered at all. In conclusion, endoscopes give accurate information about the relationship between the tumor and the adjacent structures and help control the fundus of the internal auditory canal to ensure complete tumor removal. It is also helpful in visually verifying the continuity of the facial and cochlear nerves. The use of endoscopes does not appear to increase the hearing preservation rate, but is very helpful in complete tumor removal in the posterior fossa approach.

Ultrastructural analysis of the chorda tympani nerve in chronic suppurative otitis media.

Objective: To compare ultrastructure of the chorda tympani nerve by light and electron microscopy in patients with otosclerosis and chronic suppurative otitis media. Study Design: Comparative prospective study. Setting: Tertiary care, referral medical center. Patients: The tympanic segments of chorda tympani nerves were collected for ultrastructural investigation in 20 cases with chronic suppurative otitis media and 10 cases with otosclerosis that underwent middle ear surgery. Results: Histopathologic examinations of the suppurative group showed that unmyelinated fibers were almost totally lost and replaced by collagen fibers. The thickness of the myelin sheaths was very slender, whereas some of them were atrophic. A substantial increase was encountered in the endoneural collagen substance and connective tissue, whereas inflammatory elements and edema were present occasionally. Degenerative alterations of the myelinated fibers mainly occurred in the form of adaxonal vacuoles. There was disorganization and separation of parallel lamellae of Schmidt-Lanterman clefts. Conclusion: The chorda tympani nerve should be preserved in otologic surgery. However, inadvertent dissection of the chorda tympani nerve in chronic suppurative otitis media surgery will not possibly cause a postoperative disturbance in light of ultrastructural changes that occur in the nerve.