Focal Degeneration of Vestibular Neuroepithelium in the Cristae Ampullares of Three Human Subjects.

BACKGROUND: We report a unique pattern of focal degeneration of the neuroepithelium of cristae ampullares, thick subepithelial extracellular deposits, and neural degeneration in three humans. OBJECTIVE: To characterize the pattern of vestibular degeneration and measure the thickness of subepithelial deposits in these three cases and controls. METHODS: The subepithelial deposits of vestibular end organs in three subject cases and controls were studied using hematoxylin and eosin, periotic acid-Schiff, Gomori trichrome staining, and immunostaining for antineurofilament, antimyosin VIIa, and anticollagen 4a1. The thickness of deposit as measured by light microscopy was compared with that of control groups (age-matched controls, patients with unilateral Menière's disease, vestibular neuritis, cupulolithiasis, severe nonfocal degeneration of the vestibular neuroepithelium, and Alport syndrome). The correlation of thickness of deposits with age from 0 to 100 years was also investigated. RESULTS: Focal loss of hair cells in the neuroepithelium, thick subepithelial deposits, and degeneration of subepithelial dendrites and Scarpa's ganglion were found in all three cristae of three subject cases. Immunostaining demonstrated a decrease of afferent neural fibers in the cristae and focal fragmentation of the basement membrane adjacent to the deposits. The thickness of the subepithelial deposits in three cristae of three subject cases was significantly greater than that of all controls. In the three cristae of normal controls, the thickness of deposits demonstrated a positive correlation with age. CONCLUSION: Although both age and degeneration of the vestibular neuroepithelium may be associated with the thickness of the subepithelial deposits, in this unique pattern of degeneration, the thickness of the subepithelial deposits was significantly greater than that in all controls.

Compliance and outcomes of concurrent Chemo-radiation in patients with peri-ampullary cancer undergoing curative resections.

OBJECTIVES: We aimed to study the compliance and treatment outcome of patients who received adjuvant treatment following curative resection for periampullary cancers periampullary cancers. MATERIALS AND METHODS: Institute medical records of PAC treated during 2007-2014 were retrieved. Demographics, treatment, and outcome in patients who were intended to receive adjuvant chemoradiation after curative resection were analyzed. Patients received first cycle chemotherapy with 5-fluorouracil folinic acid/capecitabine, followed by external radiotherapy 45 Gy/25 fractions/5 weeks and second and third cycle concurrent chemotherapy. Fourth and fifth cycle chemotherapy were administered after radiotherapy). Various prognostic factors, disease-free survival (DFS), and overall survival (OS) were evaluated. RESULTS: Sixty-five patients were evaluated. Median age was 50 years. 96.9% patients completed the intended course of radiation and overall adherence to chemotherapy was 86.2%. Median follow-up and DFS were 20 and 29.64 months, respectively (range: 1.9-97.3 months). Estimated 1-, 2-, 5-year DFS was 77.8%, 59.3%, and 37.6%, respectively. One-year estimated OS was 92.7%. Median DFS for node-negative and node-positive patients was 88.6 and 24.33 months (P = 0.06). Grade ≥III hematological toxicity was 20%. CONCLUSION: Positive node indicated a trend toward poor survival. The study highlights high compliance to multimodal management of PAC with acceptable toxicity in and out of clinical trial setting in a tertiary cancer center in India.

[VESTIBULAR PROSTHETICS: CONCEPT, APPROACHES, RESULTS].

Unlike prosthetic hearing, which develops technology for more than 30 years, the problem of the vestibular prosthesis developed a little more than one and half decades. Meanwhile, the involvement of the vestibular system in ensuring the normal functioning of the visual, motor and other systems of the body determines its decisive contribution to the spatial orientation of humans and animals. In case of damage of the vestibular apparatus (the labyrinth), there are serious violations of posture control, stabilization of sight, spatial orientation, psychological status, that is, in the aggregate quality of human life deteriorates. At present, on the animals developed technology of prosthetic semicircular canals, sensing angular acceleration, and control eye movements in dynamic situations. New approaches based on the replacement of the lost natural vestibular afferent impulses by electrical stimulation through multichannel vestibular prosthesis, are successfully introducing into the clinic.

Refractory Positional Vertigo With Apogeotropic Horizontal Nystagmus After Labyrinthitis: Surgical Treatment and Identification of Dysmorphic Ampullae.

OBJECTIVES: To describe the rationale, intraoperative details, and histopathologic findings discovered when treating an unusual case of apogeotropic horizontal canal positional vertigo with a transmastoid labyrinthectomy. PATIENT: A single case report. INTERVENTION: Therapeutic. MAIN OUTCOME MEASURES: Resolution of apogeotropic nystagmus and improvement of positional vertigo. RESULTS: The apogeotropic variant of horizontal canal positional vertigo can be a difficult entity to treat. This report describes a patient who developed profound sensorineural hearing loss and vertigo after an acute left labyrinthitis. Ten months later, she developed vertigo with apogeotropic positional nystagmus involving the left horizontal semicircular canal. Particle repositioning maneuvers and vestibular physical therapy were unsuccessful. In addition, she developed intermittent positional vertigo affecting the ipsilateral vertical semicircular canals. Given the persistence of her vertigo, multiple canal involvement, and patient preference for definitive treatment, a transmastoid labyrinthectomy was performed. Intraoperatively, the ampulla of the horizontal canal as well as that of the other canals was grossly abnormal as later confirmed on histology. After surgery, her apogeotropic nystagmus and vertigo resolved, and her balance ability gradually improved to a highly functional level. CONCLUSION: This case illustrates a unique form of positional vertigo that developed and persisted after acute labyrinthitis. Conservative measures were unsuccessful and a transmastoid labyrinthectomy documented dense inflammatory tissue involving all three ampullae. We postulate that the post-labyrinthitic inflammatory changes resulted in mass loading of the membranous ampullae, causing abnormal nystagmus patterns and positional vertigo, which resolved after the labyrinthectomy.

[Investigation of the reverse phase nystagmus in positioning test for benign paroxysmal positional vertigo].

OBJECTIVE: To investigate the clinical significances and formation mechanism by analyzing the characteristics of the reverse phase nystagmus parameters from benign paroxysmal positional vertigo (BPPV) positioning test. METHODS: There were 183 cases with BPPV, including 108 cases (59.0%) of posterior semicircular canal canalithiasis, 55 cases (30.1%) of horizontal semicircular canal canalithiasis, and 15 cases (8.2%) of horizontal and posterior semicircular canal cupulolithiasis and 5 cases (2.7%) of anterior semicircular canalithiasis . The video-nystagmography was utilized in positioning tests to induce nystagmus. The direction, intensity, time parameters characteristic of vertical nystagmus in Dix-Hallpike test and horizontal nystagmus in roll test were analyzed and compared. RESULTS: There were no reversal phase nystagmus in 15 cases of semicircular canal cupulolithiasis and 5 cases of anterior semicircular canalithiasis. After the disappearance of vertical nystagmus which induced by hanging position (the first phase nystagmus) in 108 cases of posterior semicircular canalithiasis of Dix-Hallpike test, there was 54 cases(50.0%) of posterior semicircular canal canalithiasis displayed downward vertical nystagmus (reverse phase nystagmus) . The latency, duration time and intensity of the first phase nystagmus and reverse phase nystagmus were [(2.00 ± 1.10) s, (3.54 ± 1.42) s], [ (16.27 ± 4.95) s, (61.65 ± 33.69)s] and [ (51.80 ± 25.25) °/s, (10.65 ± 6.29)°/s] respectively; 43 cases(78.2%) of horizontal semicircular canal canalithiasis displayed the opposite to turning head (reverse phase nystagmus) after the horizontal nystagmus, similar with turning head disappeared in Roll test. The latency, duration time and intensity of the first phase of nystagmus and reverse phase nystagmus were [ (1.67 ± 1.07) s, (3.57 ± 1.89)s], [ (25.19 ± 9.74) s, (70.48 ± 40.26)s] and [ (68.47 ± 30.18) °/s, (11.22 ± 8.78)°/s] respectively. Comparing with the latency, duration time, intensity of first phase nystagmus and reverse phase nystagmus of posterior and horizontal semicircular canal canalithiasis, the differences had statistical significances (P < 0.05). Comparing with the first phase nystagmus of reverse phase and no reverse phase nystagmus canalithiasis, the difference of nystagmus intensity had statistical significances (P < 0.05); but the differences of latency and duration of nystagmus had no significant difference (P > 0.05). CONCLUSIONS: It is common in PSC-Can and HSC-Can patients that reverse phase nystagmus is one of the clinical features of canalithiasis. It appears in side head position of Rolling test or the hanging of Dix- Hallpike test. More power of the first phase nystagmus has, reverse phase nystagmus will be induced much easier. In comparison of the reverse phase nystagmus, the first phase nystagmus has the shorter incubation and duration, but it has more power. It is helpful to avoid interruptions of clinical statolith positioning and reset since we recognize the reverse phase nystagmus. The mechanism might be similar to the vestibular mirror image nystagmus. It is another form of the vestibular mirror image nystagmus in BPPV patients.

Geometrical and volume changes of the membranous vestibular labyrinth in guinea pigs with endolymphatic hydrops.

OBJECTIVE: To evaluate geometrical and volume changes of membranous vestibular labyrinths in guinea pigs after endolymphatic hydrops (EH). METHODS: The membranous labyrinths of normal guinea pigs and of those with EH for 4 and 8 weeks were reconstructed after being scanned using micro-computed tomography subseqent to being stained in osmium tetroxide (OsO4). The diameters and volumes of the semicircular ducts, ampullae, utricles and saccules were measured based on the three-dimensional models. RESULTS: The diameters of the ampullae and utricles of EH guinea pigs were greater than those of the normal guinea pigs, while there were no significant differences in the diameters of the semicircular ducts among all groups. The volumes of ampullae, utricles and saccules of the EH groups were greater than those of the control group, but there were no changes in volumes of semicircular ducts after EH. CONCLUSION: The dilations of the membranous vestibular labyrinth in guinea pigs with EH mainly occur at the ampullae, utricles and saccules.

Frequency perception and cell injury in the semicircular canal caused by gentamicin.

OBJECTIVE: The frequency characteristics of the vestibular organ have gained notice in recent years, but the morphologic basis was unknown. This study investigated the gentamicin-induced damage of frequency-selective perception of the horizontal semicircular canal and its morphologic basis. METHODS: Eighty guinea pigs were randomly divided into four groups, one control group and three experimental groups. The experimental animals received gentamicin subcutaneously for 1 to 3 weeks. Short-latency vestibular evoked potentials evoked by 0.5 and 10 Hz step rotation stimuli following drug administration were recorded, and then the crista ampullaris of the horizontal semicircular canals was investigated by scanning and transmission electron microscopy. RESULTS: Damage to hair cells of the crista ampullaris is concentrated at the apex area first and then extends to the peripheral area of the vestibular crista ampullaris when the gentamicin administration time increased. When only the hair cells at the apex area are damaged, the high-frequency (10 Hz) rotation perception of the crista ampullaris of the horizontal semicircular canal was injured, but perceptions to 0.5 Hz step rotation stimulation remained normal. CONCLUSION: Gentamicin mainly affects the high-frequency perception function of the crista ampullaris of the horizontal semicircular canal. The hair cells at the central apex area of the crista ampullaris might be responsible for high-frequency rotation perception function.

Transcrusal approach to the retrochiasmatic region with special reference to temporal lobe retraction: an anatomical study.

BACKGROUND: The retrochiasmatic region is one of the most challenging areas to surgically expose. The authors evaluated the transcrusal approach, which involves removal of the superior and posterior semicircular canal from the ampulla to the common crus, to expose the retrochiasmatic region and compared it with the retrolabyrinthine approach, both of which are a variation of the posterior petrosal approach with hearing preservation, with a special emphasis on the influence of temporal lobe retraction. METHODS: Six sides of silicone-injected cadaveric heads were dissected using two approaches: the transcrusal approach and the retrolabyrinthine approach. For each craniotomy, 3 exposure parameters in the retrochiasmatic region were measured: (1) horizontal distance, (2) vertical distance, and (3) triangular area of exposure, at three different levels of temporal lobe retractions: 0, 5, and 10 mm of retraction from the level of the tentorial incisura. RESULTS: Without temporal lobe retraction, only the transcrusal and not the retrolabyrinthine approach provided a direct exposure of the retrochiasmatic region, especially in the horizontal distance (p < 0.001). At all levels of temporal lobe retraction, the transcrusal approach provided greater exposure in the horizontal and vertical distances and in the area of exposure. Nonetheless, in the horizontal distance, the difference between the transcrusal and retrolabyrinthine approaches decreased along with increased temporal lobe retraction, and almost no difference was obtained at 10 mm of retraction. CONCLUSIONS: Posterior petrosal approaches can provide an excellent exposure of the retrochiasmatic region. Of these two approaches, namely, transcrusal and retrolabyrinthine with hearing preservation, the transcrusal approach offers greater exposure than the retrolabyrinthine approach. The beneficial effect of partial labyrinthectomy of the transcrusal approach to the retrochiasmatic region is accentuated in the exposure of the horizontal distance with less temporal lobe retraction.

Morphological change of the cupula due to an ototoxic agent: a comparison with semicircular canal pathology.

CONCLUSION: The cupula shows various degrees of changes after gentamicin (GM) injection into the inner ear, with or without damage of the sensory cells. This cupula change may be a part of the etiology of peripheral vertigo, and is also potentially one of the mechanisms of reduced caloric response. OBJECTIVES: To observe the morphological changes of the cupula after injecting GM in the frog inner ear and to compare the changes of the cupula with those of the ampullary sensory cells. METHODS: We injected 300 microg (7.5 microl) of GM into the inner ear of 30 bullfrogs (Rana catesbeiana) using a microsyringe under ether anesthesia. The same amount of saline was injected into the other ear as control. The cupulae were observed at 3, 7, and 14 days after GM injection by stereoscopic microscope. The ampullae were fixed, and the sensory cells were assessed using a scanning electron microscope (SEM). The correlation between the changes in the cupula and sensory cells was evaluated using our own scale. RESULTS: In over half of the cupulae in the 7- and 14-day groups, cupula changes such as shrinkage were observed. In about 50% of the total cases, the degree of cupula and sensory cell change correlated in the two groups. In the 14-day group, these changes were more marked. However, there were cases in which the changes of the cupula and sensory cells did not correlate, indicating that the cupula alone can sustain changes without sensory cell damage.

Changes in transient receptor potential vanilloid (TRPV) 1, 2, 3 and 4 expression in mouse inner ear following gentamicin challenge.

CONCLUSION: It is suggested that transient receptor potential vanilloid (TRPV)-1 and -2 may be of pathological significance for sensory cells and ganglions, while TRPV-3 and -4 may play an important part in neuroprotection of the inner ear. OBJECTIVE: Changes in the expression of TRPV-1, -2, -3, and -4 in gentamicin (GM)-treated mouse inner ear were studied. MATERIALS AND METHODS: CBA/J mice were used in this study. The localization of TRPV-1, -2, -3, and -4 in the inner ear of both untreated and GM-treated CBA/J animals (intratympanic injection of 5 mg GM) was investigated by immunohistochemistry. RESULTS: TRPV-1, -2, and -3 were co-expressed in the inner ear sensory and ganglion cells, while TRPV-4 was also expressed in the stria vascularis and vestibular dark cells. Following GM treatment, the intensity of immunofluorescent reaction to TRPV-1 and TRPV-2 increased, while that to TRPV-3 and TRPV-4 decreased.

A place principle for vertigo.

OBJECTIVE: To provide a road map of the vestibular labyrinth and its innervation leading to a place principle for different forms of vertigo. METHOD: The literature describing the anatomy and physiology of the vestibular system was reviewed. RESULTS: Different forms of vertigo may be determined by the type of sense organ, type of ganglion cell and location in the vestibular nerve. CONCLUSION: Partial lesions (viral) of the vestibular ganglion are manifested as various forms of vertigo.