Hsun-Mo Wang

A comparison of the effectiveness of dexmedetomidine versus propofol target-controlled infusion for sedation during fibreoptic nasotracheal intubation.

Fibreoptic intubation is a valuable modality for airway management. This study aimed to compare the effectiveness of dexmedetomidine vs target controlled propofol infusion in providing sedation during fibreoptic intubation. Forty patients with anticipated difficult airways and due to undergo tracheal intubation for elective surgery were enrolled and randomly allocated into the dexmedetomidine group (1.0 μg.kg−1 over 10 min) (n = 20) or the propofol target controlled infusion group (n = 20). Intubating conditions and patient tolerance as graded by a scoring system were evaluated as primary outcomes. Intubation was successful in all patients. Satisfactory intubating conditions were found in both groups (19/20 in each group). The median (IOR [range]) comfort score was 2 (1–2 [1–4]) in the dexmedetomidine group and 3 (2–4 [2–5]) in the propofol group (p = 0.027), favouring the former. The dexmedetomidine group experienced fewer airway events and less heart rate response to intubation than the propofol group (p < 0.003 and p = 0.007, respectively). Both dexmedetomidine and propofol target‐controlled infusion are effective for fibreoptic intubation. Dexmedetomidine allows better tolerance, more stable haemodynamic status and preserves a patent airway.

The effectiveness of dexmedetomidine infusion for sedating oral cancer patients undergoing awake fibreoptic nasal intubation.

Background and objective Dexmedetomidine is characterized with effects of sedation, analgesia, amnesia and lack of respiratory depression. Hence, it should be suitable for awake fibreoptic intubation (AFOI). Methods We enrolled 30 oral cancer patients with limited mouth openings who were undergoing AFOI for elective surgery. Patients were randomly allocated into two groups; the Dex group (n = 16) that received dexmedetomidine (1.0 μg kg−1) infusion and the Control group (n = 14) that received fentanyl (1.0 μg kg−1) infusion. Main outcomes were evaluated by grading scores presenting conditions for nasal intubation and postintubation. Other analysed parameters included airway obstruction, haemodynamic changes, consumption time for intubation, amnesia level and satisfaction. Results Intubation score (1–5) representing condition for nasal intubation was significantly better in the Dex group [2(1–3)] than in the Control group [3(2–5)] (P = 0.001). Postintubation score (1–3) representing tolerance to intubation also showed more favourable results in the Dex group [1(1–3)] than in the Control group [2(2–3)] (P = 0.002). The Dex group showed significantly reduced haemodynamic response to intubation than the Control group. Incidence requiring temporary haemodynamic support was higher in the Dex group but not of significance. Both levels of amnesia and satisfaction score were significant in the Dex group. Other analysed parameters such as consumption time for intubation, airway obstruction score and postoperative adverse events did not differ significantly. Conclusion Combination of dexmedetomidine loading with topical anaesthesia provides significant benefit for AFOI in intubation condition, patient tolerance, haemodynamic response, amnesia and satisfaction. Dexmedetomidine is effective for AFOI in anticipated difficult airway with only minor and temporary haemodynamic adverse effects.

Electromyographic endotracheal tube placement during thyroid surgery in neuromonitoring of recurrent laryngeal nerve

Intraoperative neuromonitoring (IONM) is widely used in thyroid surgery. This study aimed to investigate the influence of neck extension on electromyographic (EMG) endotracheal tube displacement and to determine the necessity of routinely checking the final electrode position after the patient had been fully positioned. A consecutive 220 patients undergoing thyroidectomy were enrolled. All patients were intubated with the EMG endotracheal tube under direct laryngoscopy. The electrode position and tube displacement were routinely checked and measured by laryngofiberoscopy before and after patient positioning. The patients were divided into two groups. In Group I (n = 110), the EMG tube was taped and fixed to the right mouth angle before full neck extension. In Group II (n = 110), the EMG tube was disconnected from the circuit tube and was not taped until full neck extension. In all patients, we ensured that the final electrode position was the optimal position with laryngofiberoscopic examination. The tube displacement after neck extension ranged from 16 mm upward to 4 mm downward in Group I and from 12 mm upward to 5 mm downward in Group II. The rate of tube displacement greater than 10 mm was 12.7% in Group I and 3.6% in Group II. Successful monitoring was achieved in all patients after the final optimal position of electrodes was ensured routinely. The electrode position can be severely displaced after the patient has been fully positioned. Verification of ideal position of electrodes before the beginning of the operation is a necessary step to guarantee functional intraoperative neuromonitoring.

Electromyographic study of differential sensitivity to succinylcholine of the diaphragm, laryngeal and somatic muscles: a swine model.

Neuromuscular blocking agents (NMBAs) might diminish the electromyography signal of the vocalis muscles during intraoperative neuromonitoring of the recurrent laryngeal nerve. The aim of this study was to compare differential sensitivity of different muscles to succinylcholine in a swine model, and to realize the influence of NMBAs on neuromonitoring. Six male Duroc‐Landrace piglets were anesthetized with thiamylal and underwent tracheal intubation without the use of an NMBA. The left recurrent laryngeal nerve, the spinal accessory nerve, the right phrenic nerve and the brachial plexus were stimulated. Evoked potentials (electromyography signal) of four muscle groups were elicited from needle electrodes before and after intravenous succinylcholine bolus (1.0 mg/kg). Recorded muscles included the vocalis muscles, trapezius muscle, diaphragm and triceps brachii muscles. The onset time and 80% recovery of control response were recorded and analyzed. The testing was repeated after 30 minutes. The onset time of neuromuscular blocking for the vocalis muscles, trapezius muscle, diaphragm and triceps brachii muscle was 36.3 ± 6.3 seconds, 38.8 ± 14.9 seconds, 52.5 ± 9.7 seconds and 45.0 ± 8.2 seconds during the first test; and 49.3 ± 10.8 seconds, 40.0 ± 12.2 seconds, 47.5 ± 11.9 seconds and 41.3 ± 10.1 seconds during the second test. The 80% recovery of the control response for each muscle was 18.3 ± 2.7 minutes, 16.5±6.9 minutes, 8.1±2.5 minutes and 14.8±2.9 minutes during the first test; and 21.5±3.8 minutes, 12.5 ± 4.3 minutes, 10.5 ± 3.1 minutes and 16.4 ± 4.2 minutes during the second test. The sensitivity of the muscles to succinylcholine, ranked in order, was: the vocalis muscles, the triceps brachii muscle, the trapezius muscle and the diaphragm. We demonstrated a useful and reliable animal model to investigate the effects of NMBAs on intraoperative neuromonitoring. Extrapolation of these data to humans should be done with caution.

Neurofibroma of the Lingual Nerve: A Case Report

A neurofibroma of the lingual nerve is a rare clinical finding, the most common lesion site of a lingual neurofibroma being the tongue. In most situations, it is difficult to determine the precise nerve origins. Herein, we report a case of lingual nerve neurofibroma that presented as a submandibular mass, mimicking a submandibular gland tumor or solitary lymphadenopathy. Complete surgical excision of such a lesion for histopathologic examination provides a better treatment and final diagnosis. For a patient presenting with neurofibromatosis and a submandibular mass, a neurofibroma of nerve origin should be considered in the differential diagnosis.

A Comparative Study of Endoscopic and Microscopic Approach Type 1 Tympanoplasty for Simple Chronic Otitis Media.

OBJECTIVE Tympanoplasty is a common surgery for chronic otitis media. We analyzed the results of endoscopic and microscopic approaches for type 1 tympanoplasty in patients with simple chronic otitis media. MATERIALS AND METHODS We evaluated the records of 95 patients (100 ears) who underwent type 1 tympanoplasty from 2011 to 2014. Group 1 underwent tympanoplasty with a microscopic approach (50 ears), and Group 2 underwent tympanoplasty with an endoscopic approach (50 ears). The epidemiological profiles and postoperative results, including hearing gain, duration of surgery, perioperative nausea or vomiting, and graft success rate, were reviewed. RESULTS The epidemiological profiles and preoperative hearing status were similar in both groups. Postoperatively, both groups had equal improvements in hearing and air-bone gap as well as equal perforation rates. However, the endoscopic group suffered less perioperative nausea or vomiting and had a shorter operative time. CONCLUSION The endoscopic approach for tympanoplasty offers superior visualization and shorter operative time than conventional surgery, in addition to equal hearing outcomes and perforation rates. Furthermore, observations of fewer tissue injuries, better cosmetic outcomes, and lesser perioperative nausea and vomiting suggest that the endoscopic approach is a better choice for surgery.

Seizure after local anesthesia for nasopharyngeal angiofibroma.

We report a young male patient who experienced seizure after local injection of 3 mL 2% lidocaine with epinephrine 1:200,000 around a recurrent nasal angiofibroma. After receiving 100% oxygen via mask and thiamylal sodium, the patient had no residual neurologic sequelae. Seizure immediately following the injection of local anesthetics in the nasal cavity is probably due to injection into venous or arterial circulation with retrograde flow to the brain circulation. Further imaging study or angiography should be done before head and neck surgeries, especially in such highly vascular neoplasm.

The Association of GRM7 Single Nucleotide Polymorphisms with Age-Related Hearing Impairment in a Taiwanese Population

OBJECTIVES Age-related hearing impairment (ARHI) is a major disability among the elderly. This study aimed to analyze the association of single nucleotide polymorphisms (SNPs) of metabotropic glutamate receptor 7 (GRM7) gene with ARHI in an elderly population in Taiwan. MATERIALS AND METHODS This was a community-based study performed in a metropolitan hospital. Participants ≥65 years of age were recruited. Participants with a pure tone average (PTA) of speech frequencies in the better ear of >35 decibel hearing level (dBHL) were classified into the case group, whereas those with PTA ≤25 dBHL were classified into the control group. The association of SNPs rs11928865, rs1353828, rs9814809, and rs9880404 with ARHI was analyzed. RESULTS In 106 cases and 190 controls, alleles of all SNPs were found not to be associated with ARHI. The genotype of rs9880404 was found to be associated with ARHI in a dominant pattern, but the genotypes of rs11928865, rs1353828, and rs9814809 were found not to be associated with ARHI. CONCLUSION GRM7 SNPs are associated with susceptibility to ARHI, but the significance of this finding in a Taiwanese population differed from that observed in European studies. Further studies may help to determine Taiwanese (Asian)-specific SNPs associated with ARHI.

Glutathione peroxidase 3 gene polymorphisms and the risk of sudden sensorineural hearing loss

The glutathione peroxidase 3 gene (GPX3) is reported to be a risk factor for arterial ischaemic stroke and cerebral venous thrombosis. GPX3 may be one of the aetiologies of sudden sensorineural hearing loss (SSNHL), which might be attributed to the genetic effect of GPX3 by influence reactive oxygen species (ROS). Unbalanced ROS have been associated with susceptibility to SSNHL. Therefore, we conducted a case–control study with 416 SSNHL cases and 255 controls. Five single nucleotide polymorphisms (SNPs) were selected. The genotypes were determined using TaqMan genotyping assays. Each SNP was tested using the Hardy–Weinberg equilibrium (HWE), and the genetic effects were evaluated using three inheritance models. All five SNPs were in HWE. As the result, the AG genotype of rs3805435 had an adjusted odds ratio (OR) of 0.54 (95% confidence interval = 0.37–0.79, p = 0.001) compared with the AA genotype in the SSNHL cases. The GG and AG genotypes of the SNP rs3805435 were associated with SSNHL under the dominant model (p = 0.002, OR = 0.58). In conclusion, these results suggest that GPX3 polymorphisms influence susceptibility to SSNHL in southern Taiwan.

Surgical Treatment of External Auditory Canal Cholesteatoma - Ten Years of Clinical Experience

OBJECTIVE To describe the clinical manifestations of external auditory canal (EAC) cholesteatoma and evaluate the surgical outcomes of reconstruction using an inferior pedicled soft-tissue periosteum flap. MATERIALS AND METHODS A total of 28 patients were enrolled in this retrospective study conducted at Kaohsiung Medical University Hospital in Taiwan between January 2004 and December 2013. EAC cholesteatoma was classified according to the disease extent. The surgery was performed to reconstruct a smooth contour of EAC. RESULTS The average age of the 28 patients (9 males and 19 females: 30 surgical ears) was 53.7 years. The most common clinical manifestations were unilateral otalgia (63.3%) and otorrhea (46.7%), and the most frequent locations of EAC cholesteatoma with bony invasion were the posterior-inferior (40%), inferior (30%), posterior (20%), and posterior-inferior-anterior (10%) aspects. Based on Naims staging systems of EAC cholesteatoma, 26 ears (86.7%) were classified as stage III and 4 ears (13.3%) as stage IV. All patients received surgical management via a postauricular approach, and the average length of postoperative follow-up was 61.5 months (range 8-131 months). One patient had recurrence after surgery for 1 year 3 months. CONCLUSION Bony canaloplasty and obliteration with an inferior pedicled soft-tissue periosteum flap is a reliable procedure for EAC cholesteatoma.