Comparison of Conventional Excision via a Sublabial Approach and Transnasal Marsupialization for the Treatment of Nasolabial Cysts: A Prospective Randomized Study

ObjectivesSurgical excision via a sublabial approach is considered the standard treatment for nasolabial cysts. Although transnasal marsupialization has been proposed as an alternative method, no prospective study has compared the effectiveness of these techniques. We thus compared the surgical procedure, operating time, postoperative pain, complications, and recurrence rate between the two surgical methods.MethodsTwenty patients diagnosed with nasolabial cysts were allocated randomly into two groups according to the surgical technique. In the sublabial approach group, the cysts were excised completely using a sublabial approach, while in the transnasal marsupialization group, the cysts were marsupialized transnasally under the guidance of nasal endoscopes. The pure operating time was measured and postoperative pain was evaluated using a visual analog scale. Complications after the procedure were assessed and recurrence was determined according to the clinical symptoms and postoperative radiologic findings.ResultsThe transnasal marsupialization group had significantly shorter operating times, less postoperative pain, lower complication rates, and shorter duration of side effects than the sublabial approach group. No recurrence occurred in either group after a 1-yr follow-up period.ConclusionAlthough both methods are effective for treating nasolabial cysts, the transnasal marsupialization of nasolabial cysts has many benefits over the conventional sublabial approach. Therefore, we propose that transnasal marsupialization be the treatment of choice for nasolabial cysts

Long-term Study of Sialodochoplasty for Preventing Submandibular Sialolithiasis Recurrence

ObjectivesThe transoral removal of stones by sialodochoplasty has been popularized in the treatment of submandibular sialolithiasis. However, the effectiveness of sialodochoplasty is controversial, and there are no reports on the long-term outcomes of this procedure. The purpose of this study was to assess the effectiveness and long-term outcomes of sialodochoplasty in patients with submandibular sialolithiasis.MethodsWe conducted a cross-sectional study that included retrospective chart reviews and prospective telephone or interview surveys of 150 patients treated for submandibular sialolithiasis from March 2001 to January 2008. The patients were treated with two different procedures by two different surgeons. One surgeon performed a transoral sialolithectomy without sialodochoplasty in 107 patients (SS group), and the other surgeon performed a transoral sialolithectomy with sialodochoplasty in 43 patients (SP group).ResultsThe success rate of transoral sialolithectomy was 98.1% in the SS group and 93% in the SP group. The recurrence rates of symptoms or stones were 1.9% and 4.7% in the SS and SP groups, respectively. The incidence of postoperative transient hypoesthesia was 13.1% in the SS group and 34.9% in the SP group. The mean operating times were 29.79 and 47.44 minutes in the SS and SP groups, respectively. The mean percentage of general anesthesia was 42.1% in the SS group and 83.7% in the SP group.ConclusionSialodochoplasty in addition to transoral sialolithectomy for submandibular sialolithiasis did not affect the rate of symptom or stone recurrence, but did increase the postoperative hypoesthesia incidence and general anesthesia percentage

Epidemiologic survey of head and neck cancers in Korea.

Head and neck cancers have never been systematically studied for clinical purposes yet in Korea. This epidemiological survey on head and neck cancer patients was undertaken from January to December 2001 in 79 otorhinolaryngology resident-training hospitals nationwide. The number of head and neck cancer patients was 1,063 cases in the year. The largest proportion of cases arose in the larynx, as many as 488 cases, which accounted for 45.9%. It was followed by, in order of frequency, oral cavity (16.5%), oropharynx (10.0%), and hypopharynx (9.5%). The male:female ratio was 5:1, and the mean age was 60.3 yr. Surgery was the predominant treatment modality in head and neck cancers: 204 (21.5%) cases were treated with only surgery, 198 (20.8%) cases were treated with surgery and radiotherapy, 207 cases (21.8%) were treated with combined therapy of surgery, radiotherapy, and chemotherapy. Larynx and hypopharynx cancers had a stronger relationship with smoking and alcohol drinking than other primary site cancers. Of them, 21 cases were found to be metastasized at the time of diagnosis into the lung, gastrointestinal tract, bone, or brain. Coexisting second primary malignancies were found in 23 cases. At the time of diagnosis, a total of 354 cases had cervical lymph node metastasis accounting for 42.0%

A Two-Stage Algorithm to Estimate the Fundamental Frequency of Asynchronously Sampled Signals in Power Systems

A two-stage algorithm is proposed for the estimation of the fundamental frequency of asynchronously sampled signals in power systems. In the first stage, time-domain interpolation reconstructs the power system signal at a new sampling time and the reconstructed signal passes through a tuned sine filter to eliminate harmonics. In the second stage, the fundamental frequency is estimated using a modified curve fitting, which is robust to noise. The evaluation results confirm the efficiency and validity of the two-stage algorithm for accurate estimation of the fundamental frequency even for asynchronously sampled signals contaminated with noise, harmonics, and an inter-harmonic component

Zircon U–Pb ages and O–Hf isotopes of Quaternary trachytes from the East Sea: Implications for the genesis of low-δ18O magmas

Quaternary intraplate magmatism formed several volcanic islands and seamounts, including Dokdo (DD), Ulleungdo (UD), Simheungtack (ST), Anyongbok, and Isabu in the southwest of the East Sea back-arc basin. In this study, we present whole-rock geochemical, zircon U–Pb age, and in situ O–Hf isotope data for the submerged volcanic rocks from DD, UD, and ST to provide new insights into the eruption timing of these volcanoes and constrain the magma evolution processes. All samples used in this study were trachytes and exhibited ferroan, alkalic, and metaluminous to weakly peraluminous characteristics. They showed light rare earth element (REE)-enriched patterns with (La/Yb)N ratios of 25.3–31.7 and mostly negative Eu anomalies in a chondrite-normalized REE plot. In addition, they were enriched in large-ion lithophile elements and high field strength elements; they exhibited positive Pb anomalies and strongly negative Ba, Sr, P, and Ti anomalies. The zircons yielded a weighted-mean 206Pb/238U age of 2.61, 0.348–0.704, and 2.76–2.94 Ma for the DD, UD, and ST trachytes, respectively. All zircons exhibited lower δ18O values than normal depleted mantle values, regardless of the crystallization age and spatial distribution of volcanoes. The δ18O values showed no correlation with U contents or Th/U ratios, indicating that the low δ18O signatures were of primary magmatic origin. The Hf isotopic compositions of the zircons were relatively heterogeneous but predominately characterized by positive εHf values. Binary O–Hf mixing modeling revealed that low-δ18O rocks with positive εHf values from the UD and ST volcanoes were derived from a hybrid source of recycled juvenile crustal materials with low-δ18O and positive εHf signatures and an enriched mantle source with normal δ18O and negative εHf values. The juvenile oceanic crust in the source was likely metasomatized by seawater at high temperatures prior to melting. In contrast, the felsic magma that formed the DD volcanoes may have assimilated with regional basement rocks (Triassic–Jurassic granitoids), resulting in increased δ18O values and decreased εHf values relative to those of the UD and ST volcanoes. Our study highlights the significant contribution of recycled oceanic crust materials to the generation of the Quaternary magmas

Numerical and Experimental Investigations on a Variable Sonic and Subsonic Ejector

A numerical and experimental investigation of the sonic and subsonic ejector system has been conducted to develop a hydrogen recirculation ejector system for fuel cell vehicle. In this study, a new method to improve the efficiency of a hydrogen fuel cell system in variable operating conditions of the vehicle was introduced. The ejector has the variable recess length in the distance between a main nozzle exit and a mixing chamber inlet, so that it can control the secondary mass flow rate by adjusting supply pressure. The results showed that ejector in the condition of sonic and subsonic could control the recirculation ratio effectively by changing the supply pressure and position of nozzle.OAIID:oai:osos.snu.ac.kr:snu2007-01/104/0000004648/34SEQ:34PERF_CD:SNU2007-01EVAL_ITEM_CD:104USER_ID:0000004648ADJUST_YN:NEMP_ID:A001138DEPT_CD:446CITE_RATE:0FILENAME:6.2007-5749.pdfDEPT_NM:기계항공공학부EMAIL:[email protected]: