Mark R. Gacek

Cochlear Pathology in Presbycusis

A survey of the temporal bone collection at the Massachusetts Eye and Ear Infirmary reveals 21 cases that meet the criterion for the clinical diagnosis of presbycusis. It is evident that the previously advanced concept of four predominant pathologic types of presbycusis is valid, these being sensory, neural, strial, and cochlear conductive. An abrupt high-tone loss signals sensory presbycusis, a flat threshold pattern is indicative of strial presbycusis, and loss of word discrimination is characteristic of neural presbycusis. When the increments of threshold loss present a gradually decreasing linear distribution pattern on the audiometric scale and have no pathologic correlate, it is speculated that the hearing loss is caused by alterations in the physical characteristics of the cochlear duct, and the loss is identified as cochlear conductive presbycusis. It is clear that many individual cases do not separate into a specific type but have mixtures of these pathologic types and are termed mixed presbycusis. About 25% of all cases of presbycusis show none of the above characteristics and are classified as indeterminate presbycusis.

The Three Faces of Vestibular Ganglionitis

We present temporal bone and clinical evidence that common syndromes of recurrent vertigo are caused by a viral infection of the vestibular ganglion. In the present series, histopathologic and radiologic changes in the vestibular ganglion and meatal ganglion were consistent with a viral inflammation of ganglion cells in cases of Menieres disease, benign paroxysmal positional vertigo, and vestibular neuronitis. Clinical observations of multiple neuropathies involving cranial nerves V, VII, and VIII on the same side in patients with recurrent vertigo are best explained by a cranial polyganglionitis caused by a neurotrophic virus, which is reactivated by a stressful event later in life. The reactivation of the latent virus may manifest as one of the above vertigo syndromes, depending on the part of the vestibular ganglion that is inflamed, the type and strain of the virus, and host resistance.

Results of Singular Neurectomy in the Posterior Ampullary Recess

Objective: To determine the effect on hearing and balance symptoms following singular neurectomy (SN) for benign paroxysmal positional vertigo (BPPV) in the ampullary recess of the posterior semicircular canal. Research Design: The charts of 242 patients with chronic disabling BPPV who were treated with SN over a 29-year period (1972–2001) were reviewed. The results on relief of BPPV and hearing function were recorded. A subset of 16 patients where the posterior ampullary recess was entered to expose the SN is described in detail with regard to an effect on hearing and balance. Results: A total of 252 SN were performed in 242 patients. Ten patients underwent bilateral SN sequentially; the remaining 232 patients had unilateral SN. The ages of the patients ranged from 21 to 86 years, with a mean at 57 years. The female:male ratio was 174:68. Complete relief of BPPV was achieved in 244 patients (96.8%), incomplete relief in 3 (1%), and no relief in 5 (2%). Sensorineural hearing loss (SNHL) occurred in 9 patients (3.7%). A subset of 16 patients in whom the ampullary recess was opened during SN ranged in age from 21 to 79 years, with a mean at 56 years. The female:male ratio was 12:4, with right and left sides divided almost equally. Relief of BPPV was achieved in all 16 patients with no loss of hearing function. Five patients complained of a fistula response postoperatively (31%). The fistula response resolved by 6 months postoperatively in all 5 patients. Conclusions: SN is effective in relief of BPPV with little risk of SNHL (3.7%). The risk of SNHL is not increased when the posterior ampullary recess must be entered in order to transect the singular nerve. A positive fistula response may be present temporarily in almost one third of these patients.

Comparison of Labyrinthectomy and Vestibular Neurectomy in the Control of Vertigo

One hundred twenty‐six patients who were treated with labyrinthectomy (81 patients) or vestibular neurectomy (45) between the years 1979 and 1994 were reviewed. The cause for vertigo in 124 of the 126 patients was Menieres disease (89 patients), labyrinthitis (15), delayed endolymphatic hydrops (8), vestibular neuritis (7), and failed labyrinthectomy (5). In the remaining 2 patients, a normal labyrinth was sacrificed to fistulize a petrous apex cyst. Both procedures were equally effective in relieving vertigo (labyrinthectomy 98.8%; neurectomy 97.8%), but the length of hospitalization, length of disability before return to work, and cost were twice as great with vestibular neurectomy than with labyrinthectomy. More patients exhibited prolonged ataxia following neurectomy (5 patients) than after labyrinthectomy (2). Vestibular neurectomy was associated with several serious complications: reversible facial paresis (15 patients), meningitis (1), cerebrospinal fluid leak (1), and epidural hematoma (1). Labyrinthectomy was complicated by postoperative hyponatremia in 1 patient. Selective vestibular neurectomy preserved hearing in 32 (82%) of 39 patients. Criteria for recommending either ablation procedure are discussed. The incidence of sequential involvement of the contralateral ear was 1.5%.

Cricoarytenoid joint mobility after chronic vocal cord paralysis.

Eleven whole organ laryngeal specimens (10 human and 1 dog) with a history of long‐standing (6 months to 17 years) paralysis were studied histopathologically for changes in the cricoarytenoid (CA) joints and the intrinsic laryngeal musculature. In 9 cases the paralysis was unilateral and in 2 bilateral. No evidence of CA joint ankylosis (fibrous/osseous obliteration of joint space or degeneration of articular surfaces) was seen in the specimens. The absence of CA joint ankylosis permits the efficacy of thyroplasty medialization procedures.

Pseudoepitheliomatous Hyperplasia Versus Squamous Cell Carcinoma of the External Auditory Canal

Four case reports are presented to demonstrate the clinical and histopathologic similarity of pseudoepitheliomatous hyperplasia (PH) to squamous cell carcinoma (SCC) in the external auditory canal (EAC). In all four cases the original report of SCC on a biopsy specimen of an EAC lesion was corrected on review to PH. In one patient conservative management resulted in resolution of the EAC lesion. A second patient underwent radiation therapy and partial temporal bone resection with no SCC found in the surgical specimen. A third patients ear canal had healed with conservative treatment and repeated biopsy revealed no malignancy. After a 6‐year symptom‐free interval, she developed invasive SCC with bone involvement that required surgery and radiation treatment. A fourth patient underwent a sleeve resection of the skin of the EAC that proved to be PH, and no evidence of SCC was found. A thoughtful clinical history, careful physical examination, response to conservative treatment, and close communication with the pathologist should be exercised in the evaluation of EAC lesions.

Update on the Pathology and Management of Benign Paroxysmal Positional Vertigo

Objective: To describe the otopathology in benign paroxysmal positional vertigo (BPV) and report our experience with singular neurectomy (SN) over a 24-year period. Materials: (I) The temporal bones (TB) of 3 patients who demonstrated BPV before death were acquired and prepared for examination by light microscopy. (II) A clinical series of patients who underwent SN for chronic disabling BPV has been updated to December 1998. Results: (I) In each of the 3 TB representing the downmost ear in the Hallpike maneuver, two pathologic changes were observed: (1) scattered degenerative neurons were found in the facial nerve meatal ganglion (MG); (2) focal axonal degeneration of vestibular axons (2 TB) or degenerated ganglion cells (1 TB) were observed in the inferior vestibular division. (II) From 1974 to 1998, SN was performed unilaterally in 177 patients and bilaterally (sequential) in 10 patients (n = 197). The age, sex and etiologic factors in the series were consistent with the literature. In 189 patients (96%), BPV was completely relieved by SN, while 3 patients (1.5%) experienced partial relief and 5 patients (2.5%) failed to benefit from SN. Sensorineural hearing loss followed SN in 5 patients (2.5%). Conclusions: The focal degeneration in the inferior vestibular nerve or ganglion may result from reactivation of a latent neurotropic virus in inferior vestibular ganglion cells as a result of various stressors (upper respiratory infection, trauma, surgery, general anesthesia, pregnancy). The portal of entry of the virus is likely from the nose and oral cavity to the MG of the facial nerve where latency is assumed and spread to the vestibular ganglion develops. The series of 197 SN over a 24-year period demonstrates that SN is a safe, effective surgical maneuver to selectively ablate function of the posterior semicircular canal crista.

Idiopathic facial paralysis (Bell's Palsy)

Accumulating evidence indicates that idiopathic facial paralysis (IFP) is caused by a viral inflammation of the proximal portion of the facial nerve in the internal auditory canal (1). The proposed early location of the viral agent, such as herpes simplex 1, herpes zoster virus, and other members of the Herpesvirinae subfamily, has been found in the geniculate ganglion. Herpes simplex or varicella virus DNA has been recovered from the geniculate ganglion in temporal bones of patients demonstrating IFP. However, the majority of imaging studies using enhanced magnetic resonance imaging have indicated that the earliest and most proximal area of enhancement of IFP is in the meatal portion of the facial nerve (2). This location of enhancement is consistent with the intraoperative surgical observations of Fisch and Esslen (3), who proposed that the maximal swelling of the facial nerve occurs proximal to the meatal foramen. On the basis of these observations, they recommended surgical decompression of the meatal foramen and the labyrinthine segment of the facial nerve as the treatment of IFP. Recent temporal bone observations indicate that the meatal ganglion (MG) of the facial nerve demonstrates ganglion cell degeneration in addition to satellite cell and inflammatory cell infiltration in patients with IFP (4). The input to the MG is carried over the greater superficial petrosal nerve from taste receptors in the soft palate and oropharynx. This region of the pharynx is replete with viral and bacterial organisms in the overall population. It may account for the very high incidence of elevated herpes simplex virus antibodies in the general population worldwide. Figures estimating this incidence in the 70%–80% range by the age of 30 years are common. Therefore, the introduction of a neurotrophic virus (NT) such as herpes simplex virus or zoster through the oropharynx into the MG where latency is established represents a logical explanation for the neuroradiologic findings in IFP. This is the scenario for reactivation of neurotrophic virus in the MG by a stressful event at some later time in the patient’s life. The treatment of IFP with

Meatal Ganglionitis: Clinical Pathologic Correlation in Idiopathic Facial Paralysis (Bell’s Palsy)

Hypothesis: Present evidence which supports the concept that inflammation of the facial nerve (FN) meatal ganglion (MG) is the site of virus accumulation in idiopathic facial paralysis (IFP). Materials and Methods: Four bodies of evidence are used to support the hypothesis. (1) A case report of a 51-year-old female with left IFP is representative of a series with 5 patients who were monitored with MRI. Sequential MRI of the FN at 1, 8 and 15 weeks after onset of IFP monitored the inflammatory process in the FN. (2) A human temporal bone (TB) taken from an 81-year-old female who recovered from IFP 3 years before death was examined in the light microscope. (3) Eleven reports of MRI in patients with IFP were reviewed. (4) The data from 2 human TB studies describing the MG in normal and abnormal FN are summarized. Results: (1) The MRI of the FN in the majority of imaging reports of patients with IFP demonstrated enhancement of the meatal segment of the FN as the earliest focus in IFP. (2) The meatal FN segment was the earliest site of enhancement in our series of 5 patients with IFP. (3) The TB from the patient who recovered from IFP demonstrated degenerated cells in the MG and degeneration of vestibular neurons innervating cristae. (4) TB studies describe the occurrence of the MG in human FN. In the majority of FN (80%), the MG is represented by a smaller ganglion than the geniculate one. However, the MG equals or exceeds in size the geniculate ganglion in 20% of TB. A second TB study demonstrated ganglion cell lesions consistent with virally induced pathology in the MG and vestibular nerve (and ganglion) in a high percentage of TB. Conclusions: Clinical, radiologic and anatomical evidence supports meatal ganglionitis as a pathologic correlate in IFP.

Viral neuropathies in the temporal bone.

The Biology of Neurotropic Viruses Neuroanatomy of the Nerves in the Temporal Bone Meatal Ganglionitis - The Pathologic Correlate in Idiopathic Facial Paralysis Vestibular Neuronitis - A Viral Neuropathy M ni res Disease - A Form of Vestibular Ganglionitis The Pathology of Benign Paroxysmal Positional Vertigo A Classification of Recurrent Vestibulopathy Efferent System Degeneration in Vestibular Ganglionitis Antiviral Therapy of Vestibular Ganglionitis.