The American journal of otology最新文献

Hypothesis: This study aimed to analyze the localization and distribution of vessels and of these angiogenic growth factors: basic fibroblast growth factor (FGF-2), transforming growth factor-alpha (TGF-alpha), transforming growth factor-beta1 (TGF-beta1), and vascular endothelial growth factor (VEGF) in middle ear cholesteatoma in comparison with normal middle ear mucosa and auditory meatal skin.

Background: Angiogenesis is particularly important in many normal and pathologic processes, including wound healing and inflammation. Because proliferating tissues require an enhanced blood supply, angiogenesis appears to be a prerequisite for the expansion of cholesteatoma.

Methods: The expression of FGF-2, TGF-alpha, TGF-beta1, and VEGF was studied by immunohistochemistry. The amount of vessels (collagen type IV staining) was determined by an automatic imaging analyzing system.

Results: The results showed an altered expression and distribution of VEGF, FGF-2, TGF-alpha, and TGF-beta1 in cholesteatoma in relation to middle ear mucosa and auditory meatal skin. The results were consistent with rapidly growing, activated keratinocytes and stromal cells. Vascularization within the perimatrix of cholesteatoma showed a 4.3-fold increase compared with middle ear mucosa and a twofold increase compared with ear canal skin. An increase of 3.2- to 4-fold in the number of vessels was observed. A close relationship was seen between the density of capillaries, degree of inflammation, and expression of the angiogenic factors investigated, and an increased number of microvessels in cholesteatoma tissue.

Conclusions: Angiogenesis enables and supports the sustained migration of keratinocytes into the middle ear cavity. Therefore, it is a pivotal factor in the destructive behavior of middle ear cholesteatoma.

Hypothesis: To attempt to inhibit the development of myringosclerosis by intraperitoneal injection of dexamethasone.

Background: The authors' earlier report showed that the development of myringosclerosis after myringotomy was associated with an inflammatory reaction. The present study was performed to secure evidence for this hypothesis.

Methods: Three groups of bilaterally myringotomized rats were treated at 12-hour intervals with intraperitoneal injection of dexamethasone, RU486 (a glucocorticoid receptor antagonist), and saline, respectively. At 6, 12, 24, and 48 hours after the myringotomy, 2 animals were anesthetized on each occasion and examined otomicroscopically. The animals were then killed, and the tympanic membranes were excised and prepared for light microscopic studies.

Results: Dexamethasone treatment retarded and diminished the development of sclerotic lesions markedly. Moreover, no inflammatory signs were seen in the flaccida specimens. When the RU486-treated animals were compared with the animals in the control group, there were no evident differences concerning the development of myringosclerosis or the extent of the inflammatory reaction.

Conclusion: These findings confirm the earlier hypothesis that an inflammatory reaction in collagen tissue is involved in the mechanism that causes the development of myringosclerosis.

Objective: To assess the reliability of the orthodromic facial nerve action potential (FNAP), recorded from the intratemporal portion of the facial nerve on stimulation within the cerebellopontine angle.

Study design: Prospective study.

Setting: Tertiary referral center.

Patients: Ten consecutive patients undergoing translabyrinthine resection of vestibular schwannoma.

Intervention: Diagnostic.

Main outcome measures: Ten consecutive FNAPs were recorded on stimulation of the facial nerve within the cerebellopontine angle. The FNAP recording probe was placed directly on the nerve surface after the fallopian canal was opened at the second genu. Ten consecutive compound muscle action potentials (CMAPs) were recorded simultaneously from surface electrodes overlying the facial musculature, by use of a standardized electrode placement technique. The stimulating and recording equipment were removed (excluding CMAP surface electrodes) and reapplied, and FNAP and CMAP data were recorded for a second time (test/retest). Peak-to-peak amplitudes of all waveforms were calculated.

Results: The average FNAP peak-to-peak amplitude for all patients was larger than the CMAP peak-to-peak amplitude (2.60 mV and 1.07 mV, respectively). Random effects analysis of variance was performed to assess the individual components of variation. This showed that CMAP was less variable than FNAP for replicate error (10 consecutive FNAPs and CMAPs) and test/retest error. However, subject variance was less for FNAP, where subject variance was by far the largest contributor to overall variation. The reliability coefficient for FNAP was 0.995 and for the CMAP was 0.982, where absolute reliability is 1.0.

Conclusion: These data confirm that the FNAP, recorded by the technique described here, is a reliable waveform when compared with the CMAP and is a valid method for assessing facial nerve function.

Objective: To evaluate the inner anatomy of the auditory apparatus by means of virtual endoscopy of spiral computed tomography (CT) data sets.

Background: Virtual endoscopy permits simulation of the fiberoptic endoscopy perspective by processing CT or magnetic resonance images.

Methods: Seven formalin-fixed specimens of human mastoid were scanned with spiral CT with the following protocol: beam collimation 1 mm, pitch ratio 1, reconstruction spacing 0.2 to 0.5 mm, field of view 90 mm. For the generation of endoscopic views of the auditory spaces, the axial images were processed with Navigator software 2.0 running on UltraSparc I workstation.

Results: Virtual endoscopy allowed the demonstration of the external auditory canal, the head and handle of the malleus, the stapes and incudostapedial articulation, the corpus, the long process of the incus with its lenticular process and the short limb, the malleoincudal articulation, the rounded promontory, the round and oval windows, and Prussak's space. From inside the basal turn of the cochlea, virtual endoscopy showed the orifices of the fenestrae cochlea and vestibuli, the origin of the lateral and the anterior semicircular canals, and the basal turn of cochlea. The optimal perspectives that allowed demonstration of the anatomical details of the middle and inner ear are described.

Conclusion: Virtual endoscopy allows the generation of inner views of the auditory spaces. This new method of image processing can be proposed as an integrative tool of spiral CT imaging.

Objective: The aim of this study was to evaluate the efficiency of prophylactic perioperative glucocorticoid treatment during stapes surgery in preventing damage to the inner ear and reducing the frequency of early postoperative complications.

Study design: A prospective, randomized, unblinded study design was selected.

Setting: The study was conducted at an academic tertiary referral center.

Patients: Ninety-five consecutive patients undergoing erbium:YAG laser-assisted stapedotomy for otosclerosis between 1996 and 1999 were included.

Main outcome measures: The preoperative minus postoperative (1-4 days and at least 6 weeks) average pure-tone bone conduction thresholds at 1, 2, and 4 kHz were compared in the prednisolone and control groups by the Mann-Whitney U Test. In addition, the occurrences of sensorineural hearing loss of >10 dB, nystagmus, vertigo, and tinnitus were counted and evaluated by use of the Freeman-Halton or Fisher's exact test, respectively.

Results: Prophylactic perioperative prednisolone treatment was not able to improve the early postoperative average bone conduction thresholds or reduce the frequency of early sensorineural hearing loss (p > 0.5). The patients who received perioperative prednisolone treatment experienced postoperative vertigo more frequently than did the control patients (p < 0.05).

Conclusion: Perioperative cortisone prophylaxis for prevention of inner ear damage during stapes surgery is ineffective and is associated with increased postoperative patient discomfort.

Objective: To evaluate the decisional elements in the surgical strategy for extensive intratemporal cholesteatomas.

Study design: A retrospective review of cases followed up between 1985 and 1996.

Setting: Tertiary referral center.

Patients: Nineteen patients with temporal bone cholesteatoma extending beyond the middle ear limits and surgically treated were included. Preoperative imaging distinguished apical (8), infralabyrinthine (3), supralabyrinthine (3), retrolabyrinthine (1), and translabyrinthine (4) cholesteatomas.

Intervention: Apical and supralabyrinthine lesions were treated through a middle fossa approach. Infralabyrinthine and translabyrinthine locations were exposed through a subtotal petrosectomy or a transotic route, depending on the preoperative audiovestibular status and labyrinthine destruction on computed tomography. The retrolabyrinthine lesion was approached through a retrolabyrinthine route.

Main outcome measures: Patients were assessed for postoperative audiologic and facial functions and for recurrence of tumor.

Results: The facial nerve was neither rerouted nor interrupted during surgery. Among the 12 patients with preoperative facial palsy (FP), 5 cases of improvement (42%), 6 cases of stable function (50%), and 1 case of mild deterioration (8%) were observed postoperatively. In patients without preoperative FP, facial function remained unchanged postoperatively. The labyrinth could be preserved in three patients (16%), with postoperative stable hearing function in two (11%), and a 40-dB mean auditory deterioration in one (5%). Complete macroscopic resection was obtained in all patients. Two cases (11%) of postoperative recurrence were observed.

Conclusion: The surgical strategy, principally based on cholesteatoma location and preoperative auditory function, yielded a high rate of local disease control and facial function preservation.