Plasma gel as a new augmentation material for injection laryngoplasty in rabbit model: histologic analysis.

OBJECTIVES: Currently, a variety of materials are available for the treatment of glottal insufficiency. Ideal injection materials should be inexpensive, easily obtainable, nontoxic, and biocompatible. Plasma gel has recently been developed as an injectable, autologous material used in plastic surgery. The aim of this study was to evaluate the histological changes in rabbit vocal folds (VFs) after an injection of plasma gel, compared with collagen (Artecoll) or hyaluronic acid (Reviderm Intra). STUDY DESIGN: Experimental prospective animal study. SETTING: Animal laboratory. SUBJECTS AND METHODS: Blood samples were collected from 12 New Zealand rabbits. Plasma collected from each rabbit was centrifuged and processed using a gel heating system. All rabbits received a 0.05 ml injection of plasma gel into the right VF, while an equivalent volume of Artecoll or Reviderm Intra was injected into the left VFs of each 6 rabbits randomly. The larynges were collected 2, 4, and 8 weeks after injection, and the tissues were stained for histological analysis. RESULTS: In comparison with left VFs injected with Artecoll or Reviderm Intra, there was significantly less inflammatory response and foreign body reaction in the plasma gel injected right VFs (P < .05). Multinucleated foreign body type giant cells were also more prevalent in the left VFs. There were no quantitative differences in the rates of neovascularization or collagen deposition between groups. CONCLUSION: Plasma gel is a biologically compatible material that may serve as a suitable augmentation material in injection laryngoplasty. Further studies that examine the long-term effects in a larger number of subjects are needed.

Diversity of head shaking nystagmus in peripheral vestibular disease.

OBJECTIVES: To evaluate the characteristics of head shaking nystagmus in various peripheral vestibular diseases. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. MATERIALS AND METHODS: Data of 235 patients with peripheral vestibular diseases including vestibular neuritis, Ménière's disease, and benign paroxysmal positional vertigo, were retrospectively analyzed. All subjects presented between August 2009 and July 2010. Patients were tested for vestibular function including head shaking nystagmus and caloric information. Regarding vestibular neuritis, all tests were again performed during the 1-month follow-up. Head shaking nystagmus was classified as monophasic or biphasic and, according to the affected ear, was divided as ipsilesional or contralesional. RESULTS: Of the 235 patients, 87 patients revealed positive head shaking nystagmus. According to each disease, positive rates of head shaking nystagmus were as follows: 35 (100%) of 35 cases of vestibular neuritis, 11 (68.8%) of 16 cases of Ménière's disease, and 41 (22.2%) of 184 cases of benign paroxysmal positional vertigo. All cases of vestibular neuritis initially presented as a monophasic, contralesional beating, head shaking nystagmus. However, 1 month after first visit, the direction of nystagmus was changed to biphasic (contralesional first then ipsilesional beating) in 25 cases (72.5%) but not in 10 cases (27.5%). There was a significant correlation between the degree of initial caloric weakness and the biphasic conversion of head shaking nystagmus (p = 0.02). CONCLUSION: In 72.5% of vestibular neuritis cases, head shaking nystagmus was converted to biphasic during the subacute period. The larger the initial canal paresis was present, the more frequent the biphasic conversion of head shaking nystagmus occurred. However, Ménière's disease and benign paroxysmal positional vertigo did not have specific patterns of head shaking nystagmus.

Diagnostic value of only 18F-fluorodeocyglucose positron emission tomography/computed tomography-positive lymph nodes in head and neck squamous cell carcinoma.

OBJECTIVE: The role of (18)F-fluorodeocyglucose positron emission tomography (PET)/computed tomography (CT) in only PET/CT-positive lymph nodes (LNs) is not well elucidated yet. This study was conducted to evaluate the diagnostic value of only PET/CT-positive LNs without correlating positive findings on conventional imaging modalities (CT, magnetic resonance imaging [MRI], and ultrasound [US]) in patients with head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Case series with chart review. SETTING: Hallym University School of Medicine. SUBJECTS AND METHODS: From January 2006 to September 2009, 114 patients with HNSCC who underwent CT, MRI, US, and PET/CT before definitive surgery with neck dissection were reviewed. All imaging tests were interpreted on imaging-based nodal classification and were compared with histopathological findings. RESULTS: Only PET/CT-positive LNs were found at 48 nodal levels in 33 patients. Thirteen of 48 (27%) nodal levels were true-positive (TP), and 35 of 48 (73%) were false-positive (FP). Fourteen nodal levels were included on N+ necks, and 34 were included on N0 necks. In N0 necks, the FP rate was significantly higher than the TP rate (28 vs 6, P = .034). Eleven only PET/CT-positive nodal levels in 10 patients were found on the contralateral neck side, and FP was significantly more prevalent than TP (8 vs 3, P = .041). No significant difference was observed for mean standardized uptake value and LN sizes between TP and FP. CONCLUSION: Only PET/CT-positive LNs can frequently be found and do not predict LN metastasis, because a high percentage of results were FP. Our results suggest that only PET/CT-positive LNs should be considered negative, especially in N0 and contralateral necks.