[Minimally invasive low-collar incision in near total thyroidectomy].

OBJECTIVE: To explore the clinical feasibility and features of adopting a low-collar arc-shaped incision for minimally invasive near total thyroidectomy. METHODS: From April 1998 to March 2007, the procedure was accepted by 53 patients with thyroidal nodules, including nodular goiter (n = 34), thyroid adenoma (n = 12) and thyroid carcinoma (n = 7). Near total thyroidectomy was performed through a 2 - 4 cm low-collar horizontal skin incision by conventional instrumentation. RESULTS: The incision yielded excellent cosmetic results because the small and lower incisions were completely hidden by clothing collar. The recurrent laryngeal nerve and parathyroid glands were easily identified and preserved. The mean operation time was 62.2 minutes (range: 58 - 112). No complication occurred. The mean bleeding amount was 25 ml (min: 10, max: 100). The drainage was extracted at Day 2 or 3 postoperatively. The mean postoperative stay was 7.6 days (range: 7 - 12) while the post-operative follow-up 2 months to 9 years. CONCLUSION: Such technique is feasible, safe, minimally invasive, less time-consuming and cosmetically ideal. It is suitable for young and middle-aged women.

Long-distance fiber Bragg grating sensor system with a high optical signal-to-noise ratio based on a tunable fiber ring laser configuration.

A novel tunable fiber ring laser configuration with a combination of bidirectional Raman amplification and dual erbium-doped fiber (EDF) amplification is proposed for realizing high optical signal-to-noise ratio (SNR), long-distance, quasi-distributed fiber Bragg grating (FBG) sensing systems with large capacities and low cost. The hybrid Raman-EDF amplification configuration arranged in the ring laser can enhance the optical SNR of FBG sensor signals significantly owing to the good combination of the high gain of the erbium-doped fiber amplifier (EDFA) and the low noise of the Raman amplification. Such a sensing system can support a large number of FBG sensors because of the use of a tunable fiber Fabry-Perot filter located within the ring laser and spatial division multiplexing for expansion of sensor channels. Experimental results show that an excellent optical SNR of approximately 60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of approximately 170 mW at a wavelength of 1455 nm and a low EDFA pump power of approximately 40 mW at a wavelength of 980 nm, which is the highest optical SNR achieved so far for a 50 km long FBG sensor system, to our knowledge.