Vestibular assessment in sudden sensorineural hearing loss: Role in the prediction of hearing outcome and in the early detection of vascular and hydropic pathomechanisms.

Introduction: Predicting hearing outcome in sudden sensorineural hearing loss (SSNHL) is challenging, as well as detecting the underlying pathomechanisms. SSNHL could be associated with vestibular damage since cochleo-vestibular structures share the same vascularization, along with being in close anatomical proximity. Whereas viral inflammations and autoimmune/vascular disorders most likely represent the involved aetiologies, early-stage Menière's disease (MD) can also present with SSNHL. Since an early treatment could beneficially influence hearing outcome, understanding the possible etiology plays a pivotal role in orienting the most appropriate treatment. We aimed to evaluate the extent of vestibular damage in patients presenting with SSNHL with or without vertigo, investigate the prognostic role of vestibular dysfunctions on hearing recovery and detect specific lesion patterns related to the underlying pathomechanisms. Methods: We prospectively evaluated 86 patients with SSNHL. Audio-vestibular investigation included pure-tone/speech/impedance audiometry, cervical/ocular-VEMPs, vHIT and video-Frenzel examination. White matter lesions (WML) were evaluated on brain-MRI. Patients were followed-up and divided into "SSNHL-no-vertigo," "SSNHL+vertigo" and "MD" subgroups. Results: Hearing was more impaired in "SSNHL+vertigo" patients who exhibited either down-sloping or flat-type audiograms, and was less impaired in "MD" where low frequencies were mostly impaired (p < 0.001). Otolith receptors were more frequently involved than semicircular canals (SCs). Although the "SSNHL-no-vertigo" subgroup exhibited the lowest vestibular impairment (p < 0.001), 52% of patients developed otolith dysfunctions and 72% developed nystagmus. Only "MD" subjects showed anterior SC impairment and upbeating spontaneous/positional nystagmus. They more frequently exhibited cervical-VEMPs frequency tuning (p = 0.036) and ipsilesional spontaneous nystagmus (p < 0.001). "SSNHL+vertigo" subjects presented with more frequently impaired cervical-VEMPs and posterior SC and with higher number of impaired receptors (p < 0.001). They mainly exhibited contralesional spontaneous and vibration-induced nystagmus (p < 0.05) and only they showed the highest WML score and "vascular" lesion patterns (p < 0.001). Concerning the outcomes, hearing was better in "MD" and worse in "SSNHL+vertigo" (p < 0.001). Hearing recovery was mostly affected by cervical-VEMPs impairment and the number of involved receptors (p < 0.05). Patients with "vascular" lesion patterns presented with the highest HL degree and WML score (p ≤ 0.001), while none of them exhibited a complete hearing recovery (p = 0.026). Conclusions: Our data suggest that vestibular evaluation in SSNHL can provide useful information on hearing recovery and underlying aetiologies.

Case Report: Could Hennebert's Sign Be Evoked Despite Global Vestibular Impairment on Video Head Impulse Test? Considerations Upon Pathomechanisms Underlying Pressure-Induced Nystagmus due to Labyrinthine Fistula.

We describe a case series of labyrinthine fistula, characterized by Hennebert's sign (HS) elicited by tragal compression despite global hypofunction of semicircular canals (SCs) on a video-head impulse test (vHIT), and review the relevant literature. All three patients presented with different amounts of cochleo-vestibular loss, consistent with labyrinthitis likely induced by labyrinthine fistula due to different temporal bone pathologies (squamous cell carcinoma involving the external auditory canal in one case and middle ear cholesteatoma in two cases). Despite global hypofunction on vHIT proving impaired function for each SC for high accelerations, all patients developed pressure-induced nystagmus, presumably through spared and/or recovered activity for low-velocity canal afferents. In particular, two patients with isolated horizontal SC fistula developed HS with ipsilesional horizontal nystagmus due to resulting excitatory ampullopetal endolymphatic flows within horizontal canals. Conversely, the last patient with bony erosion involving all SCs developed mainly torsional nystagmus directed contralaterally due to additional inhibitory ampullopetal flows within vertical canals. Moreover, despite impaired measurements on vHIT, we found simultaneous direction-changing positional nystagmus likely due to a buoyancy mechanism within the affected horizontal canal in a case and benign paroxysmal positional vertigo involving the dehiscent posterior canal in another case. Based on our findings, we might suggest a functional dissociation between high (impaired) and low (spared/recovered) accelerations for SCs. Therefore, it could be hypothesized that HS in labyrinthine fistula might be due to the activation of regular ampullary fibers encoding low-velocity inputs, as pressure-induced nystagmus is perfectly aligned with the planes of dehiscent SCs in accordance with Ewald's laws, despite global vestibular impairment on vHIT. Moreover, we showed how pressure-induced nystagmus could present in a rare case of labyrinthine fistulas involving all canals simultaneously. Nevertheless, definite conclusions on the genesis of pressure-induced nystagmus in our patients are prevented due to the lack of objective measurements of both low-acceleration canal responses and otolith function.

Enhanced Otolith Function Despite Severe Labyrinthine Damage in a Case of Pneumolabyrinth and Pneumocephalus Due to Otogenic Meningitis Associated With Superior Canal Dehiscence.

OBJECTIVE: To describe a rare case of pneumolabyrinth (PNL) and pneumocephalus (PNC) due to otogenic meningitis in a patient with superior canal dehiscence (SCD) resulting in profound sensorineural hearing loss (SNHL), semicircular canals impairment but preservation of SCD-related enhanced otolith function. PATIENT: A 65-year-old woman with otogenic meningitis. INTERVENTION: Temporal bone high-resolution computed tomography (CT) scans, brain-magnetic resonance imaging, audiometry, bedside examination, video-head impulse test, and vestibular-evoked myogenic potentials (VEMPs). MAIN OUTCOME MEASURES: Enhanced otolith function despite canal and cochlear loss. RESULTS: The patient developed right profound SNHL and acute labyrinthitis. Imaging showed middle ear inflammatory tissue, right PNL and PNC despite lack of bony fractures. Bilateral SCD and tegmen dehiscence were detected. The patient underwent mastoidectomy, drainage of effusion, and surgical repair of tegmen dehiscence. Exploratory tympanotomy was uneventful. She was treated with intravenous antibiotics and dexamethasone for 3 weeks with improvement of general condition. At 3-weeks follow-up, right profound SNHL persisted with global hypofunction for ipsilateral semicircular canals and selective impairment for left superior canal activity at video-head impulse test. Surprisingly, both cervical and ocular-VEMPs exhibited bilaterally abnormal amplitudes and reduced thresholds, consistently with preserved SCD-related macular hypersensitivity to sounds even on the affected side. CONCLUSIONS: This case report exhibits a unique clinical scenario as it offers interesting insights concerning PNL aetiology despite lack of either bony fractures or barotrauma and PNC likely conveyed intracranially by SCD. Moreover, it provides an unusual pattern of functional dissociation among inner-ear receptors showing enhanced otolith function despite severe labyrinthine damage.

Complications of central neck dissection in patients with papillary thyroid carcinoma: results of a study on 1087 patients and review of the literature.

BACKGROUND: Prophylactic central neck dissection (CND) has been proposed in the treatment of patients affected by papillary thyroid carcinoma (PTC) with clinically negative neck lymph nodes. The procedure allows pathologic staging of lymph nodes of the central compartment and treatment of the micrometastases. Nevertheless, the morbidity that its routine use adds to the total thyroidectomy must be taken into account. The aim of this study was to characterize the morbidity that CND adds to the total thyroidectomy. METHODS: This was a retrospective study of 1087 patients with PTC and clinically negative neck lymph nodes. Patients were divided into three study groups: Group A, total thyroidectomy; Group B, total thyroidectomy and ipsilateral CND; Group C, total thyroidectomy and bilateral CND. Primary endpoints of the study were evaluated by comparing the rates of transient and permanent recurrent laryngeal nerve (RLN) injury and hypoparathyroidism in the three study groups. RESULTS: Analysis of data showed no significant differences in the rate of transient (Group A: 3.6%, Group B: 3.9%, and Group C: 5.5%; p=0.404) and permanent (Group A: 1%, Group B: 0.5%, and Group C: 2.3%; p=0.099) RLN injury between the three study groups. Both ipsilateral CND and bilateral CND were associated with a higher rate of transient hypoparathyroidism (Group: A 27.7%, Group B: 36.1%, and Group C: 51.9%; p=0.014; odds ratio [OR]: 1.477; 95% confidence interval [CI]: 1.091-2.001; p<0.001; OR: 2.827; 95% CI: 2.065-3.870, respectively). Bilateral CND had a higher rate of permanent hypoparathyroidism (Group A: 6.3%, Group B: 7%, and Group C: 16.2%; p<0.001; OR: 2.860; 95% CI: 1.725-4.743). CONCLUSIONS: The increased rates of transient and permanent hypoparathyroidism in our series suggest a critical review of indications for the routine use of prophylactic CND for PTC. Prophylactic CND ipsilateral to the tumor associated with total thyroidectomy may represent an effective strategy for reducing the rate of permanent hypoparathyroidism. Concomitant completion contralateral paratracheal lymph node neck dissection should be performed in presence of lymph node metastasis on intraoperative frozen-section pathology. This approach limits the use of bilateral CND to patients with intraoperative pathological findings of lymph node metastases.

Prognostic factors affecting neck lymph node recurrence and distant metastasis in papillary microcarcinoma of the thyroid: results of a study in 445 patients.

BACKGROUND: The management of thyroid papillary microcarcinoma (PMC) is controversial. Total thyroidectomy, thyroid lobectomy/isthmectomy, and even no treatment have been proposed. We investigated the clinical course and prognostic factors for disease recurrence and distant metastasis in 445 patients with PMC. METHODS: Data from 445 patients diagnosed with PMC in the period from 1978 to 2003 were reviewed and analyzed. Total thyroidectomy was performed in 404 patients and loboisthmusectomy in 41. Neck dissection took place in 226 patients (49.7%), with 166 of only the central compartment and 60 of both the central and lateral compartments. Radioiodine ((131)I) ablation treatment was given to 389 patients. RESULTS: Median tumor size was 7 mm (range 1-10 mm). PMC was multifocal in 156 cases (35%) and bilateral in 60 cases (13.5%). Extrathyroidal tumor extension (pT3) and neck lymph node metastasis (pN1) were present in 133 (30%) and 182 (40.9%) patients, respectively. Capsular invasion without extrathyroidal tumor extension was observed in 39 (8.7%) patients. Mean follow-up was 5.3 (range 1-26) years. Seventeen (3.8%) patients had recurrence or persistence of disease: neck recurrence (NR) in 12 (2.7%), distant metastasis (DM) in four (0.9%), NR + DM in one (0.2%). One patient (0.2%) died of the disease. Capsular invasion, extrathyroidal tumor extension (pT3), and neck lymph node metastasis at presentation (pN1) were the only independent risk factors for NR and/or DM occurrence (p < 0.05). Patients not showing these features, who were treated with loboisthmusectomy only, never experienced disease recurrence. CONCLUSION: Total thyroidectomy seems advisable in PMC with extrathyroidal extension and neck lymph node metastasis at presentation. Capsular invasion without extrathyroidal extension may suggest aggressive tumor behavior and require radical treatment.