Bone-anchored hearing implant surgery: our experience with linear incision and punch techniques.

SUMMARY: In recent years, bone-anchored hearing implants (BAHIs) have found wider application in the treatment of conductive and mixed hearing loss. Several surgical techniques have been developed to reduce complications, enhance healing and improve audiological and aesthetic results. We report our experience on the use of three BAHI surgery techniques: Group 1, linear incision with thinning of the subcutaneous tissue; Group 2, linear incision without thinning of the subcutaneous tissue; Group 3, punch technique (Minimally Invasive Ponto Surgery, MIPS). We retrospectively analysed patients undergoing BAHI surgery; results were evaluated on the basis of any intra-operative complication, duration of surgery and occurrence of adverse effects at the implantation site over 1 year of follow-up. We collected a total of 30 implantations (12 for Group 1, 8 for Group 2, 10 for Group 3) with an intra-operative complication rate of 25%, 0% and 10%, respectively. The average surgical time was 62.08 minutes, 34.37 minutes and 18.7 minutes respectively. During follow-up, we reported the occurrence of adverse effects in 10.63% of observations in Group 1, 3.12% in Group 2 and 2.5% in Group 3. This study confirms the low rate of intra and postoperative complications during BAHI surgery and documents the simplicity of execution of the novel MIPS technique, with a significant reduction in surgical time compared to the other two techniques, and positive effects in terms of health care costs.

Caloric stimulation of ampullar receptors: a new method to produce mechanically-evoked responses in frog semicircular canals.

A microthermistor positioned close to the exposed posterior semicircular canal in isolated labyrinth preparations of the frog was used to stimulate the sensory organ. Our results indicated that, depending on the position of the heater, the induced endolymphatic convection currents may result in either excitatory or inhibitory cupular deflections and thus in a modulation of ampullar receptor resting activity. Other possible thermal-dependent mechanisms, such as a direct action of the stimulus on vestibular sensors or endolymphatic volume changes, had, in the present experimental conditions, a minor role. Caloric stimulation could therefore represent a novel method to stimulate the semicircular canals 'in situ'.

Effects of caloric stimuli on frog ampullar receptors.

The observation that caloric nystagmus can be evoked even in microgravity conditions argues against Barany's convective theory. To justify this result, gravity-independent mechanisms (mainly endolymphatic volume changes and direct action of the temperature on vestibular sensors) are believed to contribute to caloric-induced activation of vestibular receptors. To define the importance of both gravity-dependent and gravity-independent mechanisms, the posterior semicircular canal of the frog was thermally stimulated by a microthermistor positioned close to the sensory organ. The stimulus produced a gravity-dependent transcupular pressure difference that, depending on the position of the heater, could result in either excitation or inhibition of ampullar receptor sensory discharge. When the heater was positioned on the ampulla, or when the canal rested on the horizontal plane, no responses could be evoked by thermal stimuli. These results suggest that, in our experimental conditions (DeltaT up to 1.5 degrees C), neither a thermally induced expansion of the endolymph nor a direct action of the temperature on vestibular sensors play any major role.

Treatment of horizontal semicircular canal benign paroxysmal positional vertigo.

We evaluated a new therapeutic maneuver-Prolonged Position on the healthy side, for Benign Paroxysmal Positional Vertigo (BPPV) of the horizontal semicircular canal. We devised this type of physical treatment in accordance with the "canalolithiasis" theory of BPPV, in order to try to free the horizontal semicircular canal of otoconial debris. We compared the results obtained by Prolonged Position with two other physical therapies by dividing our horizontal canal BPPV patients into three therapeutic groups: 1) 35 patients treated with Prolonged Position; 2) 24 patients treated with head shaking in a supine position; 3) 15 patients for whom therapy was omitted. More than 90% of the patients treated with Prolonged Position recovered within 3 days, although 6 patients out of 35 subsequently developed BPPV of the posterior semicircular canal, which then responded well to a particular repositioning maneuver. The results of Prolonged Position were significantly better than those obtained by performing head shaking or by omitting treatment. Prolonged Position can be applied to patients of all ages and general conditions and does not require hospitalization.

[Delayed endolymphatic hydrops]. / Idrope endolinfatico ritardato.

Delayed Endolymphatic Hydrops (DEH) is a disease entity that must be distinguished from idiopathic endolymphatic hydrops (Ménière's disease). Idiopathic hydrops is characterized by the following symptoms: 1) vertigo often accompanied by nausea and vomiting; 2) tinnitus; 3) hearing loss, usually fluctuating; and 4) sensation of pressure or fullness in the affected ear. Idiopathic hydrops most commonly occurs in middle-aged patients, usually between 30 and 50 years. It may involve one or both ears and usually exibits fluctuating hearing loss and episodic vertigo, although one symptom may precede the other by months or years. It is rare for Ménière's disease to present with a severe sensorineural hearing loss. Delayed Endolymphatic Hydrops was first described, under the name of "unilateral deafness with subsequent vertigo", by Wolfson and Lieberman and Nadol et al.; this was later confirmed by other authors. The disease is characterized by a profound sensorineural hearing loss in one ear, found to have been present in most cases from early childhood, due to an unknown cause, trauma or viral infections. After a prolonged period (usually many years) patients with DEH experience the onset of episodic vertigo from the deaf ear (Ipsilateral Delayed Endolymphatic Hydrops) or develop a fluctuating hearing loss and/or episodic vertigo in the opposite ear, previously with normal hearing (Controlateral Delayed Endolymphatic Hydrops). Vestibular symptoms are identical to those of Ménière's disease: in fact there is evidence that endolymphatic hydrops in the previously damaged ear or in the previously normal ear represents at least part of the labyrinthine pathology. Histopathology studies recently conducted on temporal bones of subjects affected with controlateral DEH show pathologic changes in the deaf ears similar to those found in viral labyrinthitis, whereas pathologic changes in the hearing ears resemble those known to occur in Ménière's disease. Medical treatment has not been found to be effective in patients with DEH, but it must be the first choice of treatment especially in controlateral forms of the disease. So far, surgical intervention has been demonstrated to give the best results; either conservative or more radical, depending on the type of DEH. Pharmacological labyrinthectomy with ototoxic drugs could be the therapy of choice in the future. In this paper we review the literature in order to summarize the clinical features and criteria for diagnosing DEH, we also report histopathologic findings and pathogenetic hypotheses formulated for this syndrome. Moreover, we discuss the best therapeutic approach for the ipsilateral and controlateral variants of DEH.

Epigone migraine vertigo (EMV): a late migraine equivalent.

Migrainous headache is determined by pathogenetic mechanisms that are also able to affect the peripheral and/or central vestibular system, so that vestibular symptoms may substitute and/or present with headache. We are convinced that there can be many different manifestations of vestibular disorders in migrainous patients, representing true different clinical entities due to their different characteristics and temporal relashionship with headache. Based on such considerations, we proposed a classification of vertigo and other vestibular disorders related to migraine, and believe that a particular variant of migraine-related vertigo should be introduced, namely "epigone migraine vertigo" (EMV): this could be a kind of late migraine equivalent, i.e. a kind of vertigo, migrainous in origin, starting late in the lifetime that substitutes, as an equivalent, pre-existing migraine headache. To clarify this particular clinical picture, we report three illustrative clinical cases among 28 patients collected during an observation period of 13 years (November 1991 - November 2004). For all patients, we collected complete personal clinical history. All patients underwent standard neurotological examination, looking for spontaneous-positional, gaze-evoked and caloric induced nystagmus, using an infrared video camera. We also performed a head shaking test (HST) and an head thrust test (HTT). Ocular motility was tested looking at saccades and smooth pursuit. To exclude other significant neurological pathologies, a brain magnetic resonance imaging (MRI) with gadolinium was performed. During the three months after the first visit, patients were invited to keep a diary noting frequency, intensity and duration of vertigo attacks. After that period, we suggested that they use prophylactic treatment with flunarizine (5 mg per day) and/or acetylsalicylic acid (100 mg per day), or propranolol (40 mg twice a day). All patients were again recommended to note in their diary the frequency and intensity of both headache and vertigo while taking prophylactic therapy. Control visits were programmed after 4, 12 and 24 months of therapy. All patients considerably improved symptoms with therapy: 19 subjects (68%) reported complete disappearance of vestibular symptoms, while 9 (32%) considered symptoms very improved. The subjective judgement was corroborated by data from patients diaries. We conclude that EMV is a clinical variant of typical migraine-related vertigo: a migraineassociated vertigo, headache spell independent, following a headache period, during the lifetime of a patient.