Selective extraction of pyrethroid pesticide residues from milk by solid-matrix dispersion

Fifty human temporal bones from necropsies were used to study the frequency of canal dehiscences in detail along the course of the facial nerve. Specifically, the study focused on bony dehiscences in the fallopian canal and vascular communications between the facial nerve and the surrounding bone. High frequency of dehiscences at the oval window (60%) and in the pyramidal segment (54%) were found. These dehiscence rates are in agreement with published reports. A 20% rate of dehiscences at the most anterior segment of the tympanic segment was noted and a non-reported high rate (20%) of multiple dehiscences along the course of the fallopian canal in the same temporal bone in specimens of newborns and young children. The significance of these findings in terms of clinical implications is discussed.     

Persistent parvovirus B19 infections in immunocompromised children

Significant anatomical variations within the middle ear are described as well as atypical histopathological findings in 13 selected human temporal bones. Bones studied included such vascular and bony abnormalities as carotid artery canal dehiscence, a high jugular bulb, persistent stapedial artery and facial nerve canal dehiscences. Bones also included obliterative otosclerosis, malleus head fixation and a variety of chronic inflammatory changes and/or sequelae. Those features considered to render cases prone to complications are detailed.     

Computer-aided 3-D reconstruction and measurement of the facial canal and facial nerve. I. Cross-sectional area and diameter: preliminary report

Using a computer-aided three-dimensional (3-D) reconstruction method, measurements were made at eight representative sites of diameters and the cross-sectional area of the facial canal, facial nerve, and the space between the canal and nerve. Materials used were serial histology sections of seven normal human temporal bones obtained from individuals of different ages. Two areas of decreased cross-sectional area of the facial canal were found: the proximal part of the labyrinthine portion and the middle part of the tympanic portion. These narrowings in the canal appeared to be correlated with decreased superior-inferior diameter of the facial canal in those portions, especially in adult temporal bones, and also with decreased cross-sectional area, both of the nerve and of the space between the canal and the nerve, in these portions. The developmental etiology of these narrowings is speculated on, and their possible relationship to Bell's palsy is discussed.     

Vein graft in stapes surgery

Sealing the opening of the oval window during stapes surgery is essential; it prevents postoperative complications, such as perilymph fistula and sensorineural hearing loss. In this small series of 269 cases with otosclerosis, tympanosclerosis, and congenital ossicular abnormality, vein grafting was used to seal the opening of the footplate. Hearing improvement after surgery was acceptable, and none had total hearing loss or perilymphatic fistula. World literature from the last half of this century on grafting the oval window is reviewed. Absorbable gelatin sponge (Gelfoam) seems to be causing more complications, so its use is highly discouraged. Temporalis fascia, fat, and perivenous loose areolar tissue have been used by different authors at different times in footplate surgery. The opening created in the oval window during stapes surgery must not be left uncovered.     

Herniation of the singular nerve into the round window niche

We report two cases of herniation of the singular nerve into the round window niche and one case of bony dehiscence without herniation between the round window niche and the posterior canal ampulla. It is believed that the middle ear and the inner ear are completely separate. However, in the temporal bone of a 10- to 15-week-old human fetus, a communication between the round window niche and the posterior canal ampulla is observed. Later, the mesenchymal tissue in the communication is replaced by cartilage from near the posterior canal ampulla. If the communication does not fill with cartilage, ossification is not able to begin behind the posterior canal crista. When there is bony dehiscence behind the crista, the singular nerve fibers are easily pressed out by ossified endosteal bone and herniated into the round window niche.     

Facial nerve neuromas presenting as acoustic tumors

Facial nerve tumors can present as masses in the internal auditory canal or cerebellopontine angle and may mimic an acoustic neuroma. These tumors can occur in any segment of the nerve from the brain stem to the neuromuscular junction. Prior to the advent of computed tomography and magnetic resonance imaging with gadolinium, facial nerve tumors were often difficult to diagnose. Even with these modalities it may be difficult to distinguish preoperatively between an acoustic neuroma and a facial schwannoma. Particular signs and symptoms associated with facial nerve tumors (in the spasms, and a facial tic. These symptoms, combined with modem radiologic studies, should allow for more accurate diagnosis, patient counseling, and treatment. This report presents a series of 32 facial nerve tumors diagnosed and treated at The Otology Group from 1975 to 1992. Of these lesions, 12 (38%) were thought to be acoustic neuromas. Eighteen tumors were correctly identified preoperatively as facial nerve tumors. Two facial nerve tumors were found incidentally.     

Greater petrosal nerve surgery in long-term cluster headache (author's transl)

Report on three cases with cluster headache for a period of 10 to 20 years, respectively. This was healed by resection of the greater petrosal nerve. In these patients the nerve was found in a bony canal of a length of 5 to 6 mm between the geniculate ganglion and the facial nerve hiatus. In this region the nerve was blurred free, luxated from the canal, and resected. Histological control of this part of the nerve revealed a fibrosis of the peri- and epineurium and a degeneration of some nerve fibers. Histological control in a greater number of cases is recommended.     

Retraction cholesteatoma of the sinus tympani

Posteromedial retraction of the tympanic membrane, between the oval window superiorly and the round window niche inferiorly, results in the formation of an epithelium-lined pocket within the sinus tympanic recess. Failure to recognize posterior invagination of the tympanic membrane intraoperatively leads to inadvertent tearing of the tympanomeatal flap at the level of the annulus with epithelial seeding of the middle ear and probably cholesteatoma recurrence. This article focuses on the clinical manifestations and radiographic findings suggestive of sinus tympanic epithelial retraction of the pars tensa and provides direct correlation between human cross-sectional temporal bone anatomy and otomicroscopy. The surgical management of these challenging lesions includes initial endaural access, external meatal bone removal posteromedial to the tympanic annulus and anterior to the vertical portion of the facial nerve, and middle ear ventilation after marsupialization of the epithelial retraction. Although early tympanic membrane retraction can be treated with a ventilation tube, deep epithelial pockets may require additional surgical treatment. A method for the management of sinus tympanic cholesteatomas is demonstrated.     

A steroid-responsive nephropathy in a child with human immunodeficiency virus infection

Benign paroxysmal positional vertigo developed in a patient with perilymph fistula 3 years after closure of the fistula which was in the lower margin of the annular ligament. The patient's symptoms were long-lasting and intractable. The macula utriculi and utriculoampullary nerve were irradiated by argon laser beams through the stapedectomized oval window. Singular neurectomy was performed using Argon laser, although the nerve could not be identified. After surgery, the patient's symptoms disappeared. Pure tone average of the operated side was 50 dB which remained unchanged after surgery. The macula utriculi may have been completely destroyed. Ocular counter-rolling was indicative of hypofunction of the irradiated utricle. The singular nerve may or may not have been sectioned. The ampullary nerves to the lateral canal and probably the anterior canal were intact, judging from the normal caloric reaction.     

Identification of photoacoustic transients during pulsed laser ablation of the human temporal bone: an experimental model

Laser ablation of hard tissues during neurotologic operations has been accomplished with continuous-wave (CW) lasers in the visible and midinfrared spectrum. The mechanism of ablation at these wavelengths is secondary to photothermal-induced tissue destruction. As a result, significant thermal damage to surrounding tissue may occur. Pulsed ultraviolet (UV) lasers have been suggested as an alternative to the argon, KTP-532, and CO2 lasers currently used in clinical practice. The pulse length of Excimer lasers are considerably shorter than the thermal diffusion time of bone tissue, and as a consequence thermal injury is minimal. This makes pulsed lasers an attractive tool for tissue ablation in the ear: in essence a "cold knife." However, the short pulse width of Excimer lasers (typically 10-150 ns) can create large thermoelastic stresses in the ablation specimen. This study identifies the presence of these photoacoustic waves during the Excimer laser treatment of the cadaveric human temporal bone. A XeCl (lambda = 308 nm, tau p = 12 ns) excimer laser was used to ablate hard tissue surrounding the oval window and facial ridge with energies of 75, 45, 25, and 12 mJ/pulse. Spot size was estimated to be 0.5 mm2. Custom high-frequency polyvinyldifluoride (PVDF) piezoelectric film transducers were fabricated and attached to the promontory, round window niche, and facial ridges. The signals were amplified using a low-noise preamplifier and recorded on a digitizing oscilloscope. Photoacoustic waves were clearly identified. Notably, large acoustic waves were measured on the promontory and on both sides of the facial ridge. The implications and clinical relevance of these findings is discussed and compared to findings obtained from a model system.     

Surgery in elderly patients with otosclerosis

Hearing results and complications of surgery were studied in 42 patients with otosclerosis (46 ears operated on) who were over the age of 60 years at the time of stapedectomy. The mean follow-up period was 8 years. The results were compared with those obtained in 275 patients (330 ears operated on) younger than 60 years of age undergoing stapes surgery during the same time period. Large fenestra stapedectomy with fascia seal to the oval window was used in all cases. Hearing results as judged by postoperative air-bone gaps were as good in the older age group as in the younger patients. In contrast to some earlier reports, complications of surgery such as postoperative sensorineural hearing loss occurred not more frequently among elderly patients than in younger patients. It is concluded that stapes surgery should be offered to elderly patients with the same indications as in younger patients with otosclerosis.     

Total facial nerve decompression: technique to avoid complications

Exposure of the facial nerve from the brainstem to the parotid can be accomplished without injury to the nerve, tympanic membrane, external auditory canal, ossicular chain, inner ear or structures within the cerebello-pontine angle. The procedure has reliably provided good results for patients who have had the proper indications with facial paralysis from Bell's palsy, herpes zoster oticus, infection, hemi-facial spasm, temporal bone fracture and tumors. The current technique for exposure through the mastoid, middle cranial fossa and retrolabyrinthine combined approaches are described. This technique, properly performed, is a valuable treatment for facial nerve lesions.     

Family diagnosis in psychological disorders of children and adolescents

The distribution of choline acetyltransferase messenger RNA (mRNA) among efferent vestibular neurons in the chinchilla was investigated. mRNA coding for choline acetyltransferase, the enzyme that synthesizes acetylcholine, was used as a marker for the cholinergic system. In order to retrogradely label the efferent vestibular neurons, Fluoro-gold was injected through the oval window into the inner ear of anesthetized young male chinchillas (6 to 12 months old). The animals were anesthetized and perfused through the heart 2 days post injection with 4% paraformaldehyde in phosphate buffer. Retrogradely labeled efferent vestibular neurons were mapped in brainstem sections prior to processing for in situ hybridization histochemistry using radiolabeled ribonucleic acid probes complementary to the 3' end of the choline acetyltransferase mRNA. At the levels of the ascending facial nerve and the genu of the facial nerve, we found that approximately 90% of the Fluoro-gold labeled cells in group E1 contained choline acetyltransferase mRNA. All of the group E2 cells that were labeled with Fluoro-gold were found to be cholinergic (contain choline acetyltransferase mRNA). Finally, 60% of the Fluoro-gold-labeled cells in the caudal pontine reticular nucleus contained choline acetyltransferase mRNA.     

Temporal bone findings in Pierre Robin syndrome

This is the first complete report on the histopathologic study of the temporal bones from an infant with a well-documented Pierre Robin syndrome (micrognathia, glossoptosis and cleft palate), demonstrating multiple middle and inner ear anomalies. The anomalies are basically architectural malformations rather than neutral or end organ developmental anomalies. The anomalies in this case, except for a few points, are somewhat similar in both ears. Multiple anomalies include: abnormal narrowing of the crus commune-utricle junction, superiorly located crus commune and posterior semicircular canal, underdeveloped modiolus, absence of the bony septum between the middle and apical coil (existence of scala communis in left ear), abnormally small internal auditory meatus, and abnormal direction of internal auditory canal, large cartilaginous mass around the superior semicircular canal and in the tympanic end of the fissula ante fenestram, small facial nerve, large facial bony canal dehiscence, anomalic stapes, etc.     

MRI findings of VIIth cranial nerve involvement in sarcoidosis

Right facial nerve palsy in a 58-year-old woman was due to sarcoidosis demonstrated by Gd-DTPA enhanced MRI. Abnormal enhancement of the right VIIth cranial nerve in the distal internal acoustic canal was seen on MRI. The enhancing lesion was smaller after 1 month of prednisolone 50 mg day-1. This is the first report on facial nerve involvement in neurosarcoidosis examined by Gd-DTPA enhanced MRI. The use of Gd-DTPA enhanced MRI with thin slicing, e.g. 3 mm slice thickness and 1 mm interslice gap, is effective in detecting small extramedullary lesions.     

Spatial organization of cortical and subcortical afferent projections of the neostriatum in dogs

Injury to the facial nerve in the temporal bone presents a challenge to the recovery of nerve function, in that the fallopian canal in which it lies is poorly vascularized. This study was designed to determine if wrapping an intratemporal facial nerve defect repaired with a cable graft with a well-vascularized temporoparietal fascial (TPF) flap would improve facial nerve regeneration. To evaluate this question, a defect was created in the intratemporal left facial nerve of 10 rabbits. All nerves were repaired using cable grafts. In 5 animals, the nerve graft was wrapped with temporoparietal fascia, whereas in the other 5 rabbits it was not. Three additional animals underwent exposure only. The contralateral nerve served as a control in all animals. Quantitative analysis of the nerve graft 12 weeks after repair revealed greater recovery of original fiber diameter and myelin sheath thickness in TPF flap-wrapped repairs. Histological evidence of improved neural regeneration and functional nerve recovery was also seen in the repairs where the TPF flap was utilized. Nerve conduction and electromyographic studies of the cable-grafted nerve at 6 and 12 weeks were equivocal, however.     

Cavernous haemangioma of the facial nerve

Facial nerve haemangiomas are probably the most frequent benign tumours involving the facial nerve in its intratemporal portion. Usually facial nerve dysfunction is present when these tumours are of extremely small size, the average tumour being less than 10 mm. We present a case of a 15 mm diameter cavernous haemangioma of the geniculate region, with histological findings of nerve infiltration, without facial nerve symptoms. The atypical clinical presentation justifies the report and subsequent literature review.     

Topical oxatomide: an alternative approach for the treatment of vulvar lichen sclerosus

We report a case of bilateral congenital cholesteatoma in a 6-year-old boy. Cholesteatoma was present in both ears around the tympanic isthmus (the only open passage from the tympanic cavity to the attic), extending to behind the horizontal portion of the facial nerve. This patient underwent a total of three canal wall up operations on each side to remove the cholesteatoma completely and improve hearing. This case fulfills the criteria proposed by Derlacki and Clemis in 1965. Bilateral congenital cholesteatoma is a rare condition, but the incidence of congenital cholesteatoma in children has increased recently for the following reasons: Reassessment of the criteria, the introduction of computed tomography, and increased awareness of congenital cholesteatoma. When operating on patients with bilateral cholesteatoma, the best method for preservation of hearing should be chosen. We discuss these problems in the present report.     

Fiberoptic argon laser stapedotomy: is it safe?

The history of otosclerosis surgery has been marked by major advances in both surgical technique and instrumentation. Fenestration, stapes mobilization, total stapedectomy, and stapedotomy were important advances in technique. Loupes, binocular microscopy, speculum holders, and microdrills similarly advanced instrumentation. What about fiberoptic argon laser handpieces for use in laser stapedotomy? Do they represent a significant advance in instrumentation, or are they merely another gimmick? Are fiberoptic argon laser handpieces safe? Experimentally, the thermal effects of argon laser, delivered via fiberoptic handpieces to a cadaver stapes and model vestibule, were studied. No significant temperature elevations within a model vestibule were observed during stapedotomy. There were significant temperature elevations within the laser plume at the level of the facial nerve. These findings are consistent with our experience in over 2200 primary and revision stapedotomies. To date, there have been no cases of significant hearing loss or permanent facial paralysis related to the use of these fiberoptic handpieces. We believe fiberoptic argon laser handpieces are as safe as conventional microsurgical instruments in stapes surgery.     

CT and MRI features of cavernous haemangioma of internal auditory canal

A left internal auditory canal (IAC) cavernous haemangioma is reported in a 45-year-old Saudi male. The lesion was associated with rapidly deteriorating hearing loss and facial nerve dysfunction. CT showed a calcified enhanced IAC lesion while T1 weighted MRI showed an isointense contrast enhancing lesion bulging into the porus acousticus. The imaging features of the three usual IAC lesions--meningioma, acoustic neuroma and cavernous haemangioma--were compared. Calcification/ossification appear more commonly in cavernous haemangioma than in the other two lesions while facial nerve dysfunction is a clinical hallmark of IAC cavernous haemangioma.