Hyung Kwon Byeon

Feasiblity of transoral robotic hypopharyngectomy for early-stage hypopharyngeal carcinoma.

Conventional surgical approaches for hypopharyngeal carcinomas have a great risk for developing treatment-related morbidity. To minimize this morbidity, hypopharyngectomy by transoral robotic surgery (TORS) was performed, and the efficacy and feasibility of this procedure were evaluated. TORS was performed using da Vinci Surgical Robot (Intuitive Surgical Inc., Sunnyvale, CA) in 10 patients with T1 or T2 pyriform sinus cancer and posterior pharyngeal wall cancer. FK retractor (Gyrus Medical Inc., Maple Grove, MN) was used for transoral exposure of the lesion. A face-up 30-degree endoscope was inserted through the oral cavity and two instrument arms were located in both sides of the endoscope. Pyriform sinus was totally resected as a cone-shape from the vallecular to apex region, and ipsilateral arytenoid cartilage was saved for function preservation. The aryepiglottic fold was resected medially. Laterally, the inner perichondrium of the thyroid cartilage was peeled off after perichondrium was incised horizontally to make sure of the safe margin of antero-lateral portion. The posterior margin is an inferior constrictor muscle of the posterior pharyngeal wall. We evaluated the robotic set up time, robotic operation time, blood loss, surgical margins, swallowing time, decannulation time, and surgery related complications. Transoral robotic hypopharyngectomy was performed successfully in all 10 patients. The mean robotic operation time was 62.4min, and an average of 17.5min was required for the setting of the robotic system. There was no significant perioperative complication in the cases. Swallowing function returned to all patients within 8.3days average. Decannulation was carried out within an average of 6.3days after surgery. Transoral robotic hypopharyngectomy was feasible and ontologically safe technique for the treatment of early hypopharyngeal cancer.

Oncological and functional outcomes of transoral robotic surgery for oropharyngeal cancer

In this prospective study we analysed the oncological and functional results of transoral robotic surgery (TORS) to find out if it was suitable as a minimally invasive treatment for oropharyngeal cancer. Between April 2008 and September 2011, 39 patients with oropharyngeal cancer were treated by TORS. We assessed overall and disease-free survival by the Kaplan-Meier test, and we used videopharyngography and the functional outcome swallowing scale (FOSS) to evaluate swallowing. We used nasometry to estimate hypernasality, and acoustic waveform analysis to evaluate the voice. Thirty-seven patients (95%) had histologically clear margins of resection. Overall survival at 2 years was 96% and disease-free survival 92%. An oral diet was tolerable after a mean of 6 (range 1-18) days. No serious swallowing difficulties were seen on the videopharyngogram. Thirty-six of 38 patients could swallow well (97%) with FOSS scores ranging from 0 to 2 (1 patient had a poor score but was able to take an oral diet after postural training). Voices were maintained close to the normal range on the acoustic waveform analysis. The oncological and functional results of TORS were quite acceptable for the treatment of oropharyngeal cancer. TORS is a valid treatment for selected patients with oropharyngeal cancer.

Comparison of oncologic and functional outcomes after transoral robotic lateral oropharyngectomy versus conventional surgery for T1 to T3 tonsillar cancer

We performed transoral robotic surgery (TORS) or conventional surgery via a transoral or mandibulotomy approach in patients with tonsillar cancer and prospectively analyzed the oncologic outcomes and functional recovery of the 3 groups.

Surgical techniques and treatment outcomes of transoral robotic supraglottic partial laryngectomy.

The objective of this prospective study was to confirm the validity of transoral robotic supraglottic partial laryngectomy as a conservation surgery for treating supraglottic cancer.

Significant invasion depth of early oral tongue cancer originated from the lateral border to predict regional metastases and prognosis

In oral tongue cancer, tumor depth is crucial for cervical lymph node metastasis. There is no standardized method to predict tumor invasion or deciding who should undergo selective neck dissection. In this study, calculated MRI invasion depth was compared with histopathologic (HP) invasion depth to find a correlation, and determine a cutoff value of invasion depth that predicts occult neck node metastasis. 50 patients, diagnosed with T1 or T2 oral tongue cancer originating from the lateral border of the tongue, underwent MRI screening and received surgical excision as primary treatment. MRI and HP invasion depths were compared and the cutoff value determined. The invasion depth to determine the presence of nodal metastasis where summation of specificity and sensitivity was greatest was 8.5mm HP, 10.5mm in T1 weighted enhanced axial image, and 11.5mm in T2 weighted MRI axial image. The relation coefficient of T2 weighted MRI invasion depth and HP depth was 0.851, and accuracy 84%, all of which showed higher correlation compared with T1 weighted enhanced axial image. HP depth was significantly correlated with survival rate. The measurement of invasion depth using MRI is a prerequisite for determining a surgical plan in early oral tongue cancer.

Metastasis to the submandibular gland in oral cavity squamous cell carcinomas: pathologic analysis.

Conclusion. This study demonstrates that the incidence of submandibular gland metastasis in oral cavity squamous cell carcinoma (SCC) is extremely rare and its involvement is through direct extension from a primary lesion. Therefore, if the primary lesion of the oral cavity carcinoma is not in close proximity and hence does not provide suspicion of direct extension, it may be safe to preserve the submandibular gland. Objectives. Radiotherapy may lead to injury to the salivary glands resulting in xerostomia. This study aimed to determine whether and how the submandibular gland is involved in metastases of SCC of the oral cavity and to provide an oncological basis for preservation of the submandibular gland. Patients and methods. This study reviewed the records and pathologic specimens of 201 patients who were diagnosed as having oral cavity SCC and underwent surgery at our institution, from 1991 to 2006, and pathologic metastasis to submandibular gland was evaluated. Results. In all, 44 cases (21.9%) were found to show ipsilateral level I metastasis on pathologic examination. Only two cases (1%) had carcinoma involvement in the submandibular gland. Both these two cases had direct extension from a primary lesion (retromolar trigone and floor of mouth) and no submandibular glands showed pathologic evidence of isolated metastasis or local extension of metastatic lymph nodes.

A cupulolith repositioning maneuver in the treatment of horizontal canal cupulolithiasis

OBJECTIVE We evaluated outcomes and their significance of a new treatment method for horizontal canal cupulolithiasis that could be applied regardless of the side of the cupula where otoliths are attached. METHODS Consecutive 78 patients who showed persistent apogeotropic horizontal canal positional vertigo (horizontal canal cupulolithiasis) were enrolled, and they were treated with the new cupulolith repositioning maneuver. RESULTS Horizontal semicircular canal cupulolithiasis was alleviated in 97.4% of patients, after an average of 2.1 repetitions of the maneuver. Otoliths were suspected to be attached to the canal side of the cupula in 30 cases and the utricular side in 44 cases. CONCLUSION The cupulolith repositioning maneuver is an effective method for treating horizontal canal cupulolithiasis. It may also provide an insight into the side of the cupula where otoliths are attached.

Endoscopic supraomohyoid neck dissection via a retroauricular or modified facelift approach: Preliminary results

Based on our previous experiences with endoscopic or robotic neck surgery utilizing the retroauricular (RA) or modified facelift (MFL) approach, we realized the value of verifying the feasibility of endoscopic supraomohyoid neck dissection (SOND). Therefore, the purpose of this study was to evaluate the potential role of endoscopic SOND.

Hypoxia Induces Epithelial-Mesenchymal Transition in Follicular Thyroid Cancer: Involvement of Regulation of Twist by Hypoxia Inducible Factor-1α.

Purpose Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1α (HIF-1α) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1α-induced invasive characteristics. Materials and Methods Cells were cultured under controlled hypoxic environments (1% O2) or normoxic conditions. The effect of hypoxia on HIF-1α, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1α and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1α, tissue analysis was done. Results Hypoxia induces HIF-1α expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1α via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1α with RNA interference suppressed hypoxia-induced HIF-1α and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1α. These were confirmed in the orthotopic FTC model. Conclusion Hypoxia induced HIF-1α, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.

Robot-assisted versus endoscopic submandibular gland resection via retroauricular approach: a prospective nonrandomized study

The aim of this study was to compare the short-term clinicopathological results of robot-assisted and endoscopic resection of the submandibular gland by the retroauricular approach. We present a prospective, non-random, study of 35 patients who had endoscope-assisted (n=22), or robot-assisted (n=13), resection of the submandibular gland using a retroauricular approach. Patients selected one of the two methods, and short-term clinical outcomes were then compared, including maximum diameter of the tumour and gland, length of incision, total operating time, amount of operative bleeding, amount and duration of drainage, duration of hospital stay, cosmesis, and complications. The operation was feasible in all patients with no appreciable operative complications or need to convert to a conventional open operation. The operating time of the robot-assisted group (63.4 (6.3)min) was comparable with that of the endoscopic group (66.5 (9.1)min) (p=0.15). There were no differences in the other clinical outcomes between the 2 groups. Both groups of patients were extremely satisfied with their postoperative cosmesis, and did not differ significantly (p=0.89). Robotic and endoscopic resection of the submandibular gland gave comparable early surgical outcomes and excellent cosmetic results. Despite the technical convenience for the surgeon, the robot gave no apparent clinical benefit over the endoscope in this series.