Hsin-Chien Chen

Etiology of Vocal Cord Paralysis

Objective: Vocal cord paralysis (VCP) is a sign of a certain underlying disease, a diagnosis which can be attributed to various causes. This study intends to analyze the contemporary etiology of VCP in a tertiary medical center. Materials and Methods: A retrospective review of medical records from June 2000 to December 2004 of hospitalized patients with VCP was done to determine the etiology. Results: Two hundred and ninety-one patients with a determined etiology were identified, consisting of 176 males and 115 females. Unilateral VCP was present in 259 patients, while 32 presented with bilateral VCP. The causes were surgical in 40.2%, neoplastic in 29.9%, idiopathic in 10.7%, traumatic in 8%, central in 3.8%, radiation-induced in 3.4%, inflammatory in 2%, cardiovascular in 1.7% and other causes in 0.3% of the cases. Thyroidectomy represented the most common surgery for VCP and was the cause in 57 patients. Lung cancer was responsible for 34 cases and was the most common neoplastic etiology. In males, neoplasm was the most common cause occurring in 63 of 176 males, whereas surgery was most frequent in 59 of 115 females. Conclusion: Surgical trauma, mainly thyroidectomy, is the most common cause of VCP in hospitalized patients. The possibility of a neoplasm must be ruled out before VCP is labeled idiopathic. A benign thyroid tumor could also cause VCP. Besides, radiation-induced cranial nerve paralysis in head and neck cancer may play a significant role.

Comparison of therapeutic results in sudden sensorineural hearing loss with/without additional hyperbaric oxygen therapy: a retrospective review of 465 audiologically controlled cases: Sudden sensorineural hearing loss and hyperbaric oxygen therapy

Clin. Otolaryngol. 2011, 36, 121–128

Ruptured internal carotid pseudoaneurysm in a nasopharyngeal carcinoma patient with skull base osteoradionecrosis

Nasopharyngeal carcinoma (NPC) is a major head and neck cancer with a relatively high incidence of about 5.4 per 100,000 persons in Taiwan. The primary treatment of NPC has been external radiotherapy (RT). Now with combined chemotherapy and intracavity brachytherapy, more patients enjoy a longer survival. However, radiation-induced morbidity, including xerostomia, chronic otitis media, chronic paranasal sinusitis, temporal lobe necrosis, cranial neuropathy, carotid stenosis, palatal perforation, and brainstem damage, increases with more aggressive treatment. The development of skull base osteoradionecrosis (ORN) has been reported. Rupture of irradiated great vessels is an uncommon complication, and it tends to occur in the carotid artery in patients with cancer of the head and neck. Sudden and massive hemorrhage is usually unexpected and fatal, particularly when it occurs in the nasopharynx, and it is one of the most dreaded post-RT complications among NPC patients. We describe the first published and successfully managed report of a case involving skull base ORN with a ruptured internal carotid pseudoaneurysm (PA) in NPC after irradiation.

Ultrasound-aided microbubbles facilitate the delivery of drugs to the inner ear via the round window membrane

The round window membrane (RWM) acts as a barrier between the middle ear and cochlea and can serve as a crucial route for therapeutic medications entering the inner ear via middle ear applications. In this study, we targeted the practical application of microbubbles (MBs) ultrasound on increasing the RWM permeability for facilitating drug or medication delivery to the inner ear. Using biotin-fluorescein isothiocyanate conjugates (biotin-FITC) as delivery agents and guinea pig animal models, we showed that MB ultrasound exposure can improve the inner ear system use of biotin-FITC delivery via the RWM by approximately 3.5 to 38 times that of solely soaking biotin-FITC around the RWM for spontaneous diffusion. We also showed that there was significant enhancement of hair cell uptake of gentamicin in animals whose tympanic bullas were soaked with MB-mixed gentamicin-Texas Red or gentamicin and exposed to ultrasound. Furthermore, increased permeability of the RWM from acoustic cavitation of MBs could also be visualized immediately following ultrasound exposure by using Alexa Fluor 488-conjugated phalloidin as a tracer. Most importantly, such applications had no resulting damage to the integrity of the RWM or deterioration of the hearing thresholds assessed by auditory brainstem responses. We herein provide a basis for MB ultrasound-mediated techniques with therapeutic medication delivery to the inner ear for future application in humans.

Hypoxia Induces a Metabolic Shift and Enhances the Stemness and Expansion of Cochlear Spiral Ganglion Stem/Progenitor Cells

Previously, we demonstrated that hypoxia (1% O2) enhances stemness markers and expands the cell numbers of cochlear stem/progenitor cells (SPCs). In this study, we further investigated the long-term effect of hypoxia on stemness and the bioenergetic status of cochlear spiral ganglion SPCs cultured at low oxygen tensions. Spiral ganglion SPCs were obtained from postnatal day 1 CBA/CaJ mouse pups. The measurement of oxygen consumption rate, extracellular acidification rate (ECAR), and intracellular adenosine triphosphate levels corresponding to 20% and 5% oxygen concentrations was determined using a Seahorse XF extracellular flux analyzer. After low oxygen tension cultivation for 21 days, the mean size of the hypoxia-expanded neurospheres was significantly increased at 5% O2; this correlated with high-level expression of hypoxia-inducible factor-1 alpha (Hif-1α), proliferating cell nuclear antigen (PCNA), cyclin D1, Abcg2, nestin, and Nanog proteins but downregulated expression of p27 compared to that in a normoxic condition. Low oxygen tension cultivation tended to increase the side population fraction, with a significant difference found at 5% O2 compared to that at 20% O2. In addition, hypoxia induced a metabolic energy shift of SPCs toward higher basal ECARs and higher maximum mitochondrial respiratory capacity but lower proton leak than under normoxia, where the SPC metabolism was switched toward glycolysis in long-term hypoxic cultivation.

Surgical Results of Retrograde Mastoidectomy with Primary Reconstruction of the Ear Canal and Mastoid Cavity

The aim of this study was to retrospectively review the long-term hearing results and the impact of mastoid exclusion/obliteration in patients with cholesteatoma (102 ears) who underwent retrograde tympanomastoidectomy and in whom bone chips/paté were applied as the sole materials during the procedure. In 79 ears, this was combined with ossiculoplasty in a single-stage procedure. In >71% of ears, the results of audiometric testing were monitored for more than 2 years. The results suggested there was a significant gain in hearing following surgery, with respect to the postoperative change in both air-conduction thresholds and air-bone gaps (P < 0.001). Linear regression analyses of pure-tone averages at different frequencies, before and after surgery, demonstrated that patients benefitted from a postoperative hearing gain at low and middle frequencies, but their hearing often deteriorated at frequencies of 8000 Hz. As for the impact of the type of tympanoplasty on hearing outcomes, type III-interposition markedly increased hearing gain. The overall rate of postoperative adverse events was 8.8%. We conclude that reconstruction of the ear canal and mastoid via mastoid exclusion/obliteration using bone chips/paté can be considered as an alternative procedure following retrograde mastoidectomy. It gives excellent surgical results and has fewer postoperative adverse events.

Sarcoidal granuloma in cervical lymph nodes.

Sarcoidosis is a multiorgan granulomatous disease, the most common head and neck manifestation of which is cervical lymphadenopathy. Only the presentation of sarcoidal granuloma in cervical lymph nodes without typical manifestations of systemic sarcoidosis poses a diagnostic difficulty. We describe the case of a 39-year-old male who had a 2-month history of a progressively increasing mass with soreness in his right neck. The biopsy from the neck mass demonstrated non-caseating epithelioid cell granuloma of the lymph nodes. The differential diagnoses of mycobacterial or fungal infections were excluded. Thoracic evaluations, including chest X-ray and high-resolution computed tomography, revealed no abnormal findings. Treatment with systemic corticosteroids resulted in improved clinical symptoms. No recurrence of the neck mass or other signs of systemic sarcoidosis were noted during 1.5 years of follow-up. Although our patients definitive diagnosis could not be determined, the case highlights 2 important issues: sarcoidal granuloma in lymph nodes may be a precursor of sarcoidosis, even in the absence of pulmonary or other systemic involvement; and regular follow-up is recommended in such cases.

Intratympanic steroid injection for sudden sensorineural hearing loss in a patient on hemodialysis.

Sudden sensorineural hearing loss (SSNHL) is being described with increasing incidence among patients with end‐stage renal disease (ESRD) undergoing hemodialysis (HD). There are no widely accepted guidelines in the medical literature for the appropriate management of this medical emergency. Administration of systemic steroids remains the mainstay of the management of SSNHL in conjunction with the supportive treatment, in this vulnerable group of patients, as well. However, encouraged by the evolving evidence on the efficacy of the intratympanic steroid injections (ITSI) in the treatment of SSNHL among patients without renal disease—we successfully treated SSNHL in an elderly diabetic with sepsis due to bilateral pneumonitis undergoing regular HD treatment with multiple ITSI and antibiotics resulting in complete recovery of hearing function within 3 months of onset of the first symptoms.

Effects of Microbubble Size on Ultrasound-Mediated Gene Transfection in Auditory Cells

Gene therapy for sensorineural hearing loss has recently been used to insert genes encoding functional proteins to preserve, protect, or even regenerate hair cells in the inner ear. Our previous study demonstrated a microbubble- (MB-)facilitated ultrasound (US) technique for delivering therapeutic medication to the inner ear. The present study investigated whether MB-US techniques help to enhance the efficiency of gene transfection by means of cationic liposomes on HEI-OC1 auditory cells and whether MBs of different sizes affect such efficiency. Our results demonstrated that the size of MBs was proportional to the concentration of albumin or dextrose. At a constant US power density, using 0.66, 1.32, and 2.83 μm albumin-shelled MBs increased the transfection rate as compared to the control by 30.6%, 54.1%, and 84.7%, respectively; likewise, using 1.39, 2.12, and 3.47 μm albumin-dextrose-shelled MBs increased the transfection rates by 15.9%, 34.3%, and 82.7%, respectively. The results indicate that MB-US is an effective technique to facilitate gene transfer on auditory cells in vitro. Such size-dependent MB oscillation behavior in the presence of US plays a role in enhancing gene transfer, and by manipulating the concentration of albumin or dextrose, MBs of different sizes can be produced.

Aberrant internal carotid artery in the middle ear with dehiscent high jugular bulb

OBJECTIVE We report an extremely rare case of an aberrant internal carotid artery in the middle ear, together with a dehiscent high jugular bulb, a combination never previously reported. METHODS Case report with a review of the literature. RESULTS A 24-year-old man presented with a five-year history of aural fullness, pulsatile tinnitus and mild hearing impairment in his right ear. Otoscopy revealed a retro-tympanic mass. Computed tomography of the temporal bone revealed protrusion of the right internal carotid artery into the middle-ear cavity, with a dehiscent high jugular bulb. Magnetic resonance angiography showed a reduced diameter and lateralisation of the right internal carotid artery. A diagnosis of an aberrant internal carotid artery with a dehiscent high jugular bulb was made, and the patient was managed with conservative treatment. CONCLUSION The otologist should be aware of the possibility of an aberrant internal carotid artery when the patient presents with a retro-tympanic mass, hearing loss and pulsatile tinnitus. Radiological investigation is required to make the differential diagnosis. When an aberrant internal carotid artery presents with a dehiscent high jugular bulb, the risk of serious bleeding is elevated. We recommend a conservative approach for cases presenting without bleeding complications.