Anatomic Measurements of Distances from Lateral Surface of Cranium to Cochlea in Congenital Aural Atresia and Stenosis Patients

<b><i>Introduction:</i></b> Studies have shown that higher response levels can be obtained when the bone conduction stimulation position is closer to the cochlea. However, the morphological characteristics of round window niche and posterior tympanum in congenital aural atresia (CAA) and stenosis (CAS) patients were different from the normal. These affected the position of the cochlea at the cranial base. It was still unknown whether the distances from the cranium of CAA and CAS patients to the cochlea were the same as those of normal patients or not. <b><i>Objective:</i></b> To measure distances from various points on the lateral surface of the cranium to the cochlea and the cranium thickness on these points among a CAA group, CAS group and normal control group, which may provide valuable information for the better position of bone conduction stimulation. <b><i>Methods:</i></b> CT images of CAA, CAS patients and these patients’ healthy sides were analyzed. Firstly, the Frankfurt horizontal plane (Pfrkt) was established. Secondly, a model of part of the cranium was three-dimensionally reconstructed. Then, the Pfrkt plane was rotated down 20, 30 and 40° according to the superior margin of the external auditory canal. At every angle, points 25, 30, 35 and 40 mm away from the superior margin of the external auditory canal were marked out on the surface of the model and recorded as P₂₀A, P₃₀A, P₄₀A, P₂₀B, etc. The spatial distances between the cranium and ipsilateral cochlea were defined as lengths of points on the surface of the model to the cochlea apex (CA), cochlear base (CB) and modiolus midpoint (MM), respectively, recorded as P₂₀A/CA, P₂₀A/CB, P₂₀A/MM, P₃₀A/CA, etc. <b><i>Results and Conclusions:</i></b> In all groups, the length of P₂₀D/CA was the shortest compared to P₃₀D/CA and P₄₀D/CA (<i>p</i> &#x3c; 0.05). The P₂₀A/CB and P₂₀A/MM were also the shortest (<i>p</i> &#x3c; 0.05). When the Pfrkt plane was rotated down 30 and 40°, the results were the same as at 20° (<i>p</i> &#x3c; 0.05). However, P₂₀D, P₃₀D and P₄₀D were almost on the mastoid air cells. We suggest that the bone conduction stimulation position is placed closer to the ear, while avoiding the mastoid air cells in the CAA and CAS patients.

Correlation between tympanometry volume and three-dimensional computed tomography mastoid volumetry in tympanoplasty candidates

Objective Ventilation of the middle ear and mastoid air cells is believed to play an important role in the pathogenesis of chronic ear disease. Traditionally, ventilation is assessed by computed tomography. However, this exposes patients to cumulative radiation injury. In cases with a perforation in the tympanic membrane, tympanometry potentially presents a non-invasive alternative to measure the ventilated middle-ear and mastoid air cell volume. This study hypothesised that total tympanometry volume correlates with ventilated middle-ear and mastoid air cell volume. Method Total tympanometry volume was compared with ventilated middle-ear and mastoid air cell volume on computed tomography scans in 20 tympanic membrane perforations. Results There was a high correlation between tympanometry and computed tomography volumes (r = 0.78; p < 0.001). A tympanometry volume more than 2 ml predicted good ventilation on computed tomography. Conclusion These results may help reduce the need for pre-operative computed tomography in uncomplicated cases with tympanic membrane perforations.

Rare incidence of tension pneumocephalus 2 months after repeat microvascular decompression

Background: Tension pneumocephalus is a rare complication after intracranial procedures and craniotomy. We report a rare case of intraventricular and subdural tension pneumocephalus occurring 2 months after repeat right-sided microvascular decompression (MVD) for recurrent trigeminal neuralgia. Case Description: The patient in this case was a 79-year-old woman who presented with acute-onset confusion, headaches, nausea, and vomiting. On computed tomography, substantial volumes of pneumocephalus in the fourth ventricle and subdural space at the site of the retrosigmoid exposure for the previous MVD were seen. She underwent emergent wound exploration, and no obvious dural defect or exposed mastoid air cells were identified. The dura was reopened, and the surgical site was copiously irrigated. Mastoid air cells were covered with ample amounts of bone wax, and the wound was closed. The patient recovered well postoperatively with complete resolution of the pneumocephalus by her 3-month follow-up evaluation. Conclusion: It is important to assess for cerebrospinal fluid leakage and that air cells are sealed off before wound closure to prevent a pathway for air to egress into the surgical cavity and corridor.

Correlation of Status of Mastoid with Outcomes of Myringoplasty with Cortical Mastoidectomy in Mucosal Otitis Media with High Risk Perforation

Introduction Chronic mucosal otitis media is one of the common disease prevalent in our society. This study was done to correlate the status of mastoid with outcomes of myringoplasty with cortical mastoidectomy in mucosal otitis media with high risk perforation. MethodsThis prospective, observational study was done at Department of Otorhinolaryngology and Head and Neck Surgery, Tribhuvan University Teaching Hospital. Thirty-four patients of ag|e 15 and above with chronic mucosal otitis media having high-risk perforation undergoing cortical mastoidectomy with myringoplasty were included. The status of middle ear, aditus, and mastoid air cells were assessed. Post-operatively, patients were assessed for graft uptake and hearing after three months. The post-operative graft uptake and hearing results were correlated with the peroperative status. Four patients who had preoperative sensorineural hearing loss were studied in terms of graft uptake only. ResultsThe graft success rate in patients with normal mastoid air cells was 90% whereas in diseased cases was 71.4% which was statistically not significant with p value 0.20. The success rate in terms of hearing was 68.8% in normal mastoid whereas it was 64.3% in diseased mastoid which was statistically not significant with p-value of 1. ConclusionIn correlation with the status of mastoid air cells with graft uptake and hearing result, the observed differences were not statistically significant. However, averages of post-operative air conduction threshold and air-bone gap of all cases were better as compared to preoperative levels.

OTO MASTOIDITIS AND SEPTIC CEREBRAL VENOUS THROMBOSIS

11 yr old female child, admitted with history of fever, left ear pain, swelling behind the left ear of 5 days duration, for which she was treated by a nearby doctor. After 1 week the child had left ear discharge, headache, neck pain, recurrent episodes of vomiting. On general examination she is thin built, febrile, toxic and dehydrated. On local examination she had ear discharge, swelling behind the left ear. On neurological examination, she had neck stifness. Routine blood investigations including, CBC, LFT, RFT were normal. On CSF examination Protein-188 mg%,Sugar- 16 mg%,Cell count-165 cells/cumm,85% were Neutrophils. Aural swab C/S showed growth of Klebsiella sensitive to Amikacin, Ciprooxacin, Piperacillin / Tazobactum and Cotrimoxazole. ENT opinion was in favour of doing Mastoidectomy. HRCT Temporal bone showed complete opacication of external auditory canal, tympanic cavity and mastoid air cells with a possibility of lling up with pus. MRI BRAIN showed Left mastoid and postauricular abscess, mastoiditis, ventriculitis, venulitis with thrombosis of left transverse and sigmoid sinuses. Patient was treated with parenteral piperacillin tazobactum, Ciprooxacin, Amikacin, Metronidazole, Mannitol, Dexamethasone and Low molecular weight heparin.Patient improved in 3 weeks.Ear discharge dried up, mastoid abscess subsided, and the child became active and ambulant

Endoscopic transmastoid posterior petrosal approach for locally aggressive tumors in the petrous part of the temporal bone involving the internal auditory canal, jugular foramen, and hypoglossal canal

OBJECTIVEThe posterior petrosal approach is an established surgical method offering wide access to skull base lesions through mastoid air cells. The authors describe their experience with the endoscopic transmastoid “posterior petrosal” approach (EPPAP) for skull base tumors involving the internal auditory canal (IAC), jugular foramen, and hypoglossal canal.METHODSThe EPPAP was performed for 7 tumors (3 chordomas, 2 chondrosarcomas, 1 schwannoma, and 1 solitary fibrous tumor). All surgical procedures were performed under endoscopic visualization with mastoidectomy. The compact bone of the mastoid air cells and posterior surface of the petrous bone are carefully removed behind the semicircular canals. When removal of cancellous bone is extended superomedially through the infralabyrinthine space, the surgeon can expose the IAC and petrous portion of the internal carotid artery to reach the petrous apex (infralabyrinthine route). When removal of cancellous bone is extended inferomedially along the sigmoid sinus, the surgeon can safely reach the jugular foramen (transjugular route). Drilling of the inferior surface of petrous bone is extended further inferoposteriorly behind the jugular bulb to approach the hypoglossal canal and parapharyngeal space through the lateral aspect of the occipital condyle (infrajugular route).RESULTSOf the 7 tumors, gross-total resection was achieved in 4 (57.1%), subtotal resection (> 95% removal) in 2 (28.6%), and partial resection (90% removal) in 1 (14.2%). Postoperatively, 2 of 3 patients with exudative otitis media showed improvement of hearing deterioration, as did 2 patients with tinnitus. Hypoglossal nerve palsy and swallowing difficulty were improved after surgery in 2 patients and 1 patient, respectively. In 1 patient with severe cranial nerve deficits before surgery, symptoms did not show any improvement.CONCLUSIONSThe authors present their preliminary experience with EPPAP for skull base tumors in the petrous part of the temporal bone and the lateral part of the occipital condyle involving the cranial nerves and internal carotid arteries. The microscope showed a higher-quality image and illumination in the low-power field. However, the endoscope could offer wider visualization of the surgical field and contribute to minimizing the size of the surgical pathways, necessity of brain retraction, and eventually the invasiveness of surgery. Thus, the EPPAP may be safe and effective for skull base tumors in the petrous region, achieving balance between the radicality and invasiveness of the skull base surgery.

COMPARATIVE STUDY BETWEEN UNDERLAY AND OVERRLAY TECHNIQUE IN TYPE 1 TYMPANOPLASTY IN CSOM MUCOSAL INACTIVE TYPE

Otitis Media (OM) is an inflammatory condition which usually involves muco-periosteal covering of middle ear cleft (partial or full) comprising of eustachain tube (ET), hypo-tympanum, meso-tympanum, epi-tympanum,additus and the mastoid air cells. Myringoplasty was introduced by Berthold5 long back in 1878 and included the surgical closure of tympanic membrane perforation including removal of epithelium and grafting with skin. This period witnessed an improvement in surgical techniques with improved optics and emergence of microsurgery, thus making the Myringoplasty safer and lowered the rate of graft rejection. In this study we have compared the the grafting technique in type-1 tympanoplasty of in CSOM mucosal inactive type.