In Vivo Measurement of Ear Ossicle and Bony Wall Vibration by Sound Stimulation of Cartilage Conduction.

The cartilage-conduction pathway was recently proposed as a third auditory pathway; however, middle-ear vibrations have not yet been investigated in vivo. We aimed to measure the ossicles and bone vibration upon cartilage-conduction stimulation with a non-contact laser Doppler vibrometer. We recruited adult patients with normal ear structures who underwent cochlear implant surgery at our hospital between April 2020 and December 2022. For sound input, a cartilage-conduction transducer, custom-made by RION Corporation (Tokyo, Japan), was fixed to the surface of the tragus and connected to an audiometer to regulate the output. A posterior tympanotomy was performed and a laser beam was directed through the cavity to measure the vibration of the ossicles, cochlear promontory, and posterior wall of the external auditory canal. Five participants (three men, mean age: 56.4 years) were included. The mean hearing loss on the operative side was 96.3 dB HL in one patient, and that of the other patients was off-scale. The vibrations were measured at a sound input of 1 kHz and 60 dB. We observed vibrations of all three structures, demonstrating the existence of cartilage-conduction pathways in vivo. These results may help uncover the mechanisms of the cartilage-conduction pathway in the future.

Primary Closure With Posteriorly Based Lateral Tongue Flap Reconstruction After Transoral Videolaryngoscopic Surgery for Tonsil Cancer.

INTRODUCTION: Transoral surgery for head and neck cancer provides excellent oncologic outcomes while preserving speech and swallowing function. When neck dissection and resection of oropharynx are performed concomitantly, there is a risk of creating a communication defect or developing a pharyngocutaneous fistula. To prevent pharyngocutaneous fistula, we performed the reconstruction using a posteriorly based lateral tongue flap for communication defect. PATIENT: A 72-year-old male with oropharyngeal cancer (tonsil cancer) T2N1M0 underwent concomitant transoral videolaryngoscopic surgery and neck dissection. The lateral wall of the oropharynx was resected with the pharynx constrictor muscle and parapharyngeal fat due to infiltration of the parapharyngeal space by the tonsil cancer. The posteriorly based lateral tongue flap was used to close the perforation. There was no leakage to the neck postoperatively. The patient had no problem with phonation or oral intake and remained free of disease at 12 months after treatment. CONCLUSION: For a small defect confined to the oropharyngeal lateral wall, the posteriorly based lateral tongue flap should be considered as a useful option for reconstruction of the oropharynx without impairment of posterior function.

Complete response to pembrolizumab in recurrent nested variant of urothelial carcinoma.

INTRODUCTION: The nested variant of urothelial carcinoma is rare and shows poor prognosis. We report a case of complete response to pembrolizumab in recurrent nested variant. CASE PRESENTATION: A 50-year-old man visited another hospital with hematuria and weight loss. Clinical stage T4aN0M0 bladder cancer and acute renal failure were diagnosed. He was referred to our hospital and underwent radical cystectomy. Histological examination showed pathological stage T4aN2 nested variant of urothelial carcinoma. He received 3 cycles of gemcitabine and carboplatin adjuvant chemotherapy. However, para-aortic lymph node metastasis appeared 7 months after cystectomy. He received pembrolizumab as systemic chemotherapy. After 10 cycles, the lesion remained undetectable and we evaluated the response as complete. He has received 18 cycles in total and no recurrences or metastases have been observed. CONCLUSION: Pembrolizumab may offer effective treatment for nested variant of urothelial carcinoma.

A Novel Concept for Surgical Management of a Traumatic Comminuted Cricoid Fracture.

The cricoid plays 2 key roles: phonation and maintenance of the airway frame, both of which are lost in cases of comminuted cricoid fractures. The management of these 2 functions becomes a challenge in planning surgical treatment. We report the treatment course in a case of traumatic comminuted cricoid fracture that was resolved with good airway and phonatory functions. A 25-year-old man fell down the stairs and complained of respiratory discomfort and hoarseness of voice. A computed tomography scan showed comminuted cricoid fracture; therefore, surgery was performed to restore the patient's airway and phonation functions. We found that the airway was maintained by the anterior part and that the phonation depended on the posterior part of the cricoid. This novel concept helped clarify the treatment goal in this case of comminuted cricoid fractures. Furthermore, it is important that the anterior part of the cricoid is reconstructed with sufficient internal diameter, while the posterior part of the cricoid is reconstructed in the correct position.

C6-ceramide Inhibits the Motility of Anaplastic Thyroid Carcinoma Cells.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is an aggressive type of thyroid cancer, and its metastasis requires cell motility. Ceramide is involved in a variety of biological processes, including inflammation, cell signaling, cell motility, and induction of apoptosis, however has not previously been reported to inhibit the motility of ATC cells. We evaluated the effect of short chain C6-ceramide on motility of ATC cells. METHODS: Cell motility of 8305C thyroid carcinoma cell line treated with C6-ceramide was assessed using a transwell migration assay and a pseudopodia formation assay. RESULTS: Treatment with 10 µM C6-ceramide resulted in significantly fewer migratory cells than control treatment in a transwell migration assay (P < 0.002). In condition medium, 82.6% of C6-ceramide-treated cells formed lamellipodia. Importantly, treatment with 10 µM C6-ceramide drastically decreased the number of cells forming lamellipodia by 17.6% (P < 0.01). CONCLUSION: Our results suggest that treatment with a low concentration of ceramide may prevent metastasis and recurrence of ATC by inhibiting cell motility. Further studies are necessary to investigate the mechanism of inhibition of cell motility by ceramide. Ceramide shows promise as a therapeutic treatment for ATC.

A total pleural covering of absorbable cellulose mesh prevents pneumothorax recurrence in patients with Birt-Hogg-Dubé syndrome.

BACKGROUND: Birt-Hogg-Dubé syndrome (BHDS) is a recently recognized inherited multiple cystic lung disease causing recurrent pneumothoraces. Similarly to the lesions in patients with lymphangioleiomyomatosis (LAM), the pulmonary cysts are innumerable and widely dispersed and cannot all be removed. We recently described a total pleural covering (TPC) that covers the entire visceral pleura with oxidized regenerated cellulose (ORC) mesh. TPC successfully prevented the recurrence of pneumothorax in LAM patients. The purpose of this study was to evaluate the effect of an ORC pleural covering on pneumothorax recurrence in BHDS patients. RESULTS: This retrospective study enrolled a total of 81 pneumothorax patients with the diagnosis of BHDS who underwent 90 covering surgeries from January 2010 to August 2017 at Tamagawa Hospital. During the first half of the study period, a lower pleural covering (LPC) which covered the affected area with ORC mesh was mainly used to treat 38 pneumothoraces. During the second half of the study period, TPC was primarily performed for 52 pneumothoraces. All the thoracoscopic surgeries were successfully performed without serious complications (≥ Clavien-Dindo grade III). The median follow-up periods after LPC/TPC were 66/34 months, respectively. Pneumothorax recurrence rates after LPC at 2.5/5/7.5 years postoperatively were 5.4/12/42%, respectively; none of the patients who had underwent TPC developed postoperative pneumothorax recurrence (P = 0.032). CONCLUSIONS: TPC might be an effective option for surgical treatment of intractable pneumothorax in patients with BHDS.

Ultrasound-Guided Transoral Videolaryngoscopic Surgery for Retropharyngeal Lymph Node Metastasis of Papillary Thyroid Cancer.

BACKGROUND: Endoscopic-assisted transoral surgery, including transoral robotic surgery for metastatic retropharyngeal lymph node (RPN) from well-differentiated thyroid cancer, has been reported to reduce the complications resulting from transcervical and transmandibular approaches. However, the narrow working space and difficulty identifying RPN are problematic. To solve these issues, several studies have used intraoperative ultrasound in endoscopic-assisted transoral surgery. However, the type of ultrasonography suitable for this purpose remains unclear. CASE PRESENTATION: A 60-year-old female with thyroid papillary carcinoma (T4aN1bM0) initially underwent total thyroidectomy and paratracheal and selective neck dissections (D2a), with resectional management of recurrent laryngeal nerve, trachea, and esophagus. Three years later, she was diagnosed with left retropharyngeal and upper mediastinal lymph node metastases of papillary thyroid cancer. Transoral videolaryngoscopic surgery was performed with a combination of ultrasonography with a flexible laparoscopic transducer manipulated with forceps for identifying RPN intraoperatively. Due to the transducer's small size and thin, flexible cable, the transducer interrupted the procedure in spite of the narrowness of oral cavity. RPN was resected completely without adverse events. CONCLUSION: We performed intraoperative ultrasound-guided endoscopic transoral surgery for metastatic RPN from papillary thyroid cancer and achieved complete resection as well as preservation of swallowing function.

Sequential motion of the ossicular chain measured by laser Doppler vibrometry.

OBJECTIVE: In order to help a surgeon make the best decision, a more objective method of measuring ossicular motion is required. METHODS: A laser Doppler vibrometer was mounted on a surgical microscope. To measure ossicular chain vibrations, eight patients with cochlear implants were investigated. To assess the motions of the ossicular chain, velocities at five points were measured with tonal stimuli of 1 and 3 kHz, which yielded reproducible results. The sequential amplitude change at each point was calculated with phase shifting from the tonal stimulus. Motion of the ossicular chain was visualized from the averaged results using the graphics application. RESULTS: The head of the malleus and the body of the incus showed synchronized movement as one unit. In contrast, the stapes (incudostapedial joint and posterior crus) moved synchronously in opposite phase to the malleus and incus. The amplitudes at 1 kHz were almost twice those at 3 kHz. CONCLUSIONS: Our results show that the malleus and incus unit and the stapes move with a phase difference.

A novel reflex cough testing device.

BACKGROUND: The reflex cough test is useful for detecting silent aspiration, a risk factor for aspiration pneumonia. However, assessing the risk of aspiration pneumonia requires measuring not only the cough reflex but also cough strength. Currently, no reflex cough testing device is available that can directly measure reflex cough strength. We therefore developed a new testing device that can easily and simultaneously measure cough strength and the time until the cough reflex, and verified whether screening with this new instrument is feasible for evaluating the risk of aspiration pneumonia. METHODS: This device consists of a special pipe with a double lumen, a nebulizer, and an electronic spirometer. We used a solution of prescription-grade L-tartaric acid to initiate the cough reflex. The solution was inhaled through a mouthpiece as a microaerosol produced by an ultrasonic nebulizer. The peak cough flow (PCF) of the induced cough was measured with the spirometer. The 70 patients who participated in this study comprised 49 patients without a history of pneumonia (group A), 21 patients with a history of pneumonia (group B), and 10 healthy volunteers (control group). RESULTS: With the novel device, PCF and time until cough reflex could be measured without adverse effects. The PCF values were 118.3 ± 64.0 L/min, 47.7 ± 38.5 L/min, and 254.9 ± 83.8 L/min in group A, group B, and the control group, respectively. The PCF of group B was significantly lower than that of group A and the control group (p < 0.0001), while that of group B was significantly lower than that of the control group (p < 0.0001). The time until the cough reflex was 4.2 ± 5.9 s, 7.0 ± 7.0 s, and 1 s in group A, group B, and the control group, respectively. This duration was significantly longer for groups A and B than for the control group (A: p < 0.001, B: p < 0.001), but there was no significant difference between groups A and B (p = 0.0907). CONCLUSION: Our newly developed device can easily and simultaneously measure the time until the cough reflex and the strength of involuntary coughs for assessment of patients at risk of aspiration pneumonia.

Modifications to the Fenestration Approach for Arytenoid Adduction Under Local Anesthesia.

OBJECTIVE: We modified the fenestration approach for arytenoid adduction to make it easier to perform the surgery. The aim of this study was to evaluate the usefulness of our modifications, which included (1) use of an Alexis wound retractor (Applied Medical) to secure the surgical field through a small incision, and (2) use of a 12-mm, 1/2 R, insert-molded taper needle with 3-0 nylon suture to prevent damage to the arytenoid cartilage. STUDY DESIGN: This is a retrospective non-randomized observational cross-sectional study. METHODS: We compared the operative time and skin incision length between the conventional fenestration approach and our modified procedure, and verified the improvement of patients' voice by our procedure. RESULTS: Seven patients underwent the conventional fenestration approach for arytenoid adduction with type I thyroplasty, whereas nine patients underwent our modified fenestration approach for arytenoid adduction with type I thyroplasty. The skin incision length with our modifications (median, 3.0 cm; interquartile range [IQR], 3.0-4.0) was significantly shorter than with the conventional procedure (median, 5.0 cm; IQR, 4.3-5.8) (P = 0.001). The operative time with our modifications (median, 95 minutes; IQR, 90-100) was significantly shorter than without our modifications (median, 115; IQR, 100-130) (P = 0.035). All patients who underwent our modified fenestration approach for arytenoid adduction had maximum phonation time greater than 11 seconds after surgery. CONCLUSIONS: Our two distinctive modifications reduced the operative time and skin incision length for the fenestration approach, which improved the procedure by making it less invasive.

Haploinsufficiency of the folliculin gene leads to impaired functions of lung fibroblasts in patients with Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant inherited disorder caused by germline mutations in the FLCN gene, and characterized by skin fibrofolliculomas, multiple lung cysts, spontaneous pneumothorax, and renal neoplasms. Pulmonary manifestations frequently develop earlier than other organ involvements, prompting a diagnosis of BHDS However, the mechanism of lung cyst formation and pathogenesis of pneumothorax have not yet been clarified. Fibroblasts were isolated from lung tissues obtained from patients with BHDS (n = 12) and lung cancer (n = 10) as controls. The functional abilities of these lung fibroblasts were evaluated by the tests for chemotaxis to fibronectin and three-dimensional (3-D) gel contraction. Fibroblasts from BHDS patients showed diminished chemotaxis as compared with fibroblasts from controls. Expression of fibronectin and TGF-ß1 was significantly reduced in BHDS fibroblasts when assessed by qPCR Addition of TGF-ß1 in culture medium of BHDS lung fibroblasts significantly restored these cells' abilities of chemotaxis and gel contraction. Human fetal lung fibroblasts (HFL-1) exhibited reduced chemotaxis and 3-D gel contraction when FLCN expression was knocked down. To the contrary, a significant increase in chemotactic activity toward to fibronectin was demonstrated when wild-type FLCN was overexpressed, whereas transduction of mutant FLCN showed no effect on chemotaxis. Our results suggest that FLCN is associated with chemotaxis in lung fibroblasts. Together with reduced TGF-ß1 expression by BHDS lung fibroblasts, a state of FLCN haploinsufficiency may cause lung fibroblast dysfunction, thereby impairing tissue repair. These may reveal one mechanism of lung cyst formation and pneumothorax in BHDS patients.

Analysis of Direct Simultaneous Measurement of Glottal Airflow Velocity, Subglottal Pressure, and High-Speed Imaging Using Flexible Transnasal Endoscope in a Human Subject.

It is difficult to directly observe glottal airflow velocity just above the glottis due to sensor size requirements and limited accessibility. We developed a miniature hot-wire probe and flexible fiberscopic high-speed imaging system for human examinations. Simultaneous direct measurement of glottal airflow velocity, subglottal pressure, and vocal fold vibration was achieved in a patient who was treated with a T-tube for tracheal stenosis. Airflow velocity changes at the anterior midline of the vocal folds were synchronized with subglottal pressure changes during each phonation cycle. The velocity at the anterior midline of the vocal folds showed a rhythmic pattern of sharp, high peaks. The result of fast Fourier transform analysis indicated that glottal velocity at the anterior midline of the vocal folds had abundant high-frequency components that were not affected by resonance of the vocal tract. Airflow velocity was variable and diminished except at the anterior midline of the vocal folds.

A Total Pleural Covering for Lymphangioleiomyomatosis Prevents Pneumothorax Recurrence.

BACKGROUND: Spontaneous pneumothorax is a major and frequently recurrent complication of lymphangioleiomyomatosis (LAM). Despite the customary use of pleurodesis to manage pnenumothorax, the recurrence rate remains high, and accompanying pleural adhesions cause serious bleeding during subsequent lung transplantation. Therefore, we have developed a technique of total pleural covering (TPC) for LAM to wrap the entire visceral pleura with sheets of oxidized regenerated cellulose (ORC) mesh, thereby reinforcing the affected visceral pleura and preventing recurrence. METHODS: Since January 2003, TPC has been applied during video-assisted thoracoscopic surgery for the treatment of LAM. The medical records of LAM patients who had TPC since that time and until August 2014 are reviewed. RESULTS: TPC was performed in 43 LAM patients (54 hemithoraces), 11 of whom required TPC bilaterally. Pneumothorax recurred in 14 hemithoraces (25.9%) from 11 patients (25.6%) after TPC. Kaplan-Meier estimates of recurrence-free hemithorax were 80.8% at 2.5 years, 71.7% at 5 years, 71.7% at 7.5 years, and 61.4% at 9 years. The recurrence-free probability was significantly better when 10 or more sheets of ORC mesh were utilized for TPC (P = 0.0018). TPC significantly reduced the frequency of pneumothorax: 0.544 ± 0.606 episode/month (mean ± SD) before TPC vs. 0.008 ± 0.019 after TPC (P<0.0001). Grade IIIa postoperative complications were found in 13 TPC surgeries (24.1%). CONCLUSIONS: TPC successfully prevented the recurrence of pneumothorax in LAM, was minimally invasive and rarely caused restrictive ventilatory impairment.

A Qualitative Study of Confusing Experiences among Japanese Adult Patients with Type 1 Diabetes.

BACKGROUND: In this study, we investigated the powerlessness of patients with type 1 diabetes (T1D), and described the structure of powerlessness that these individuals experienced. In order for patients to recover from this state, we recommend that they take steps to regain their power. METHODS: Fifteen Japanese adults with T1D participated in this study. Data were collected from all subjects between July 2013 and March 2014 via in-depth semi-structured interviews. Qualitative data analysis was conducted according to a grounded theory approach. Finally, the core category was identified, which allowed us to build a new powerlessness structure for T1D. RESULTS: The results suggested a core category, 'Wandering a tangled path,' comprising four categories, eight subcategories, and twenty-six concepts. These four categories were as follows: 'being burdened by T1D,' 'suffering from insulin-related troubles,' 'being unable to cope with difficulties in self-management,' and 'facing social prejudice.' In the state of powerlessness, negative emotional experiences snowballed, with patients feeling more and more depressed until they ultimately reached 'rock bottom.' CONCLUSION: We found that as negative emotional experiences related to powerlessness increased, negative feelings intensified until the patients reached rock bottom. Powerlessness is like 'wandering a tangled path,' a state in which T1D patients struggle to cope with reality on their own when faced with both internal and external events. 'Wandering a tangled path' is at the core of powerlessness. A primary characteristic of the structure of powerlessness is suffering from confusing experiences. To help patients cope with T1D without being crushed by powerlessness, nurses must pay attention to signs of powerlessness. Powerlessness is not just an emotional state, but a combination of feelings, perceptions, and thoughts; therefore, it is important to comprehensively understand patients' narratives.

Post-laryngectomy voice rehabilitation with a voice prosthesis in a young girl with advanced thyroid cancer.

The aim of this report is to evaluate the effects of voice rehabilitation with a voice prosthesis in a young patient with thyroid cancer. A 17-year-old girl underwent voice restoration with a voice prosthesis after laryngectomy to treat thyroid cancer. She completed voice-related questionnaires (the Voice Handicap Index-10 and Voice-Related Quality Of Life Survey) at ages 17 and 21 and underwent phonetic functional evaluation. The sound spectrograms of her phonation using the voice prosthesis showed low frequency sounds without an obvious basic frequency. She was ashamed of her hoarse voice and did not use her voice prosthesis during high school. However, after beginning to work at age 20, she used her voice to communicate in the workplace. At age 21, her questionnaire scores, especially those related to the physical and functional domains, improved compared with those at age 17. Voice restoration with a voice prosthesis is recommended for young patients who undergo laryngectomy for advanced thyroid cancer. The advantages of voice restoration with a voice prosthesis may increase when the patient reaches working age, and it may improve post-laryngectomy quality of life considerably.

Relationship between quality of life instruments and phonatory function in tracheoesophageal speech with voice prosthesis.

BACKGROUND: The use of tracheoesophageal speech with voice prosthesis (T-E speech) after total laryngectomy has increased recently as a method of vocalization following laryngeal cancer. Previous research has not investigated the relationship between quality of life (QOL) and phonatory function in those using T-E speech. This study aimed to demonstrate the relationship between phonatory function and both comprehensive health-related QOL and QOL related to speech in people using T-E speech. METHODS: The subjects of the study were 20 male patients using T-E speech after total laryngectomy. At a visit to our clinic, the subjects underwent a phonatory function test and completed three questionnaires: the MOS 8-Item Short-Form Health Survey (SF-8), the Voice Handicap Index-10 (VHI-10), and the Voice-Related Quality of Life (V-RQOL) Measure. RESULTS: A significant correlation was observed between the physical component summary (PCS), a summary score of SF-8, and VHI-10. Additionally, a significant correlation was observed between the SF-8 mental component summary (MCS) and both VHI-10 and VRQOL. Significant correlations were also observed between voice intensity in the phonatory function test and both VHI-10 and V-RQOL. Finally, voice intensity was significantly correlated with the SF-8 PCS. CONCLUSIONS: QOL questionnaires and phonatory function tests showed that, in people using T-E speech after total laryngectomy, voice intensity was correlated with comprehensive QOL, including physical and mental health. This finding suggests that voice intensity can be used as a performance index for speech rehabilitation.

Preliminary study of transoral robotic surgery for pharyngeal cancer in Japan.

Transoral robotic surgery (TORS) with the da Vinci Surgical System has been used for the removal of pharyngeal and laryngeal cancers with the objective to improve functional and aesthetic outcomes without worsening survival. While TORS has been approved in many countries, Japan's FDA has not yet done so. Our hospital started using TORS with the approval of the Ethical Review Board and the Minimum Invasive Surgical Center Committee at Tottori University. No surgical outcomes of TORS for Japanese patients with head and neck cancer have been reported in Japan. This paper deals with the outcomes and feasibility of TORS for Japanese patients with pharyngeal cancer at our institution. TORS was performed for 10 patients with T1, T2, T3 oropharyngeal and hypopharyngeal squamous cell carcinoma between 2013 and 2014. This is a single-institutional study. TORS could be completed for all cases, except one patient that was not candidate, and no intraoperative conversion to an open surgical procedure was required. Five patients underwent neck dissection, two of them concurrent and three staged. Of all patients, positive surgical margins were detected in two. The average blood loss including neck dissection was 21.5 ± 33.4 ml, the operation time was 183 ± 36 min and the console time was 103 ± 22 min. No tracheostomy had been performed either pre- or postoperatively, and there was no difference between preoperative and postoperative swallowing functions. In this single-institutional preliminary study, we demonstrated that TORS is a feasible and safe treatment. A clinical multi-institutional study of TORS for laryngopharyngeal cancer has been approved as an advanced medical system study and is under way. In the near future, it is expected that the efficacy and safety of TORS for laryngopharyngeal cancer will be confirmed as the result of this multiple-institutional clinical study in Japan.

Opinions and Satisfaction Regarding Continuous Subcutaneous Insulin Infusion Therapy in Adult Patients with Type 1 Diabetes.

BACKGROUND: This study examined the treatment satisfaction of type 1 diabetic patients undergoing continuous subcutaneous insulin infusion (CSII) therapy, and patients' thoughts regarding CSII. METHODS: We provided a self-administered questionnaire survey over the internet. Participants were 106 individuals with type-one diabetes aged 20 years or older, undergoing CSII. The survey examined patients' treatment satisfaction, and their thoughts regarding CSII. Descriptive statistics were calculated. We compared relationships between treatment satisfaction and other variables using the Kruskal-Wallis rank sum test, and performed content analysis on participants' thoughts regarding CSII. RESULTS: Regarding treatment satisfaction, the response, "neither of them" was the most frequent. Comparing relationships between treatment satisfaction and other variables, significant differences were found for the variables "age," "presence of dissatisfaction regarding doctors' response," and "presence of a significant medical expense burden." Participants' thoughts regarding CSII were classified into 10 categories. CONCLUSION: Participants expressed positive evaluations, such as that their blood sugar control had improved due to CSII, and that they perceived improvement in their health. Participants also expressed negative evaluations, however, such as that medical expenses resulting from CSII were high, and that these expenses may cause distress and future economic insecurity. In future, patients may benefit from nursing support that allows patients to confidently continue with CSII.

Mechanical evaluation of newly developed mouthpiece using polyethylene terephthalate glycol for transoral robotic surgery.

Transoral robotic surgery (TORS), performed with the da Vinci surgical system (da Vinci), has been classified as a surgical approach for benign and malignant lesions of the oral cavity and laryngopharynx. It provides several unique advantages, which include a three-dimensional magnified view, ability to see and work around curves or angles, and the availability of two or three robotic arms. At present, however, the da Vinci surgical system does not provide haptic feedback. The potential risks specific to the transoral use of the da Vinci include tooth injury, mucosal laceration, ocular injury, and mandibular fracture. To prevent such intra-operative tooth injuries, we created a mouthpiece made of polyethylene terephthalate glycol (PETG) individually shaped for the patient's teeth. We compared the safety and efficacy of the PETG mouthpiece with those of a conventional mouthpiece made of ethylene-vinyl acetate (EVA). To determine the difference in tooth injury resulting from the two types of mouthpiece, we constructed an experimental system to measure load and strain. We measured the dynamic load and the strain from the rod to the tooth using the PETG and EVA mouthpiece. The rod was pressed against the tooth model outfitted with two types of mouthpiece and the dynamic load was measured with a load cell and the strain with a strain gage. The maximum dynamic load was 1.29 ± 0.03 kgf for the PETG mouthpiece and 2.24 ± 0.05 kgf for the EVA mouthpiece. The load against the tooth was thus less for the EVA mouthpiece. The strain was -166.84 ± 3.94 and 48.24 ± 7.77 µÎµ, respectively, while the load direction was parallel to that of the tooth axis for the PETG mouthpiece and perpendicular to the tooth axis for the EVA mouthpiece. The PETG mouthpiece reduced the tooth load compared with the EVA mouthpiece and the load direction was in parallel to the tooth axis. The PETG mouthpiece thus enhances tooth safety for TORS.

Clinical characteristics of catamenial and non-catamenial thoracic endometriosis-related pneumothorax.

BACKGROUND AND OBJECTIVE: A major pathogenic factor for catamenial pneumothorax is thoracic endometriosis. However, thoracic endometriosis-related pneumothorax (TERP) can develop as either catamenial or non-catamenial pneumothorax (CP). Therefore, the aim of this study was to elucidate the clinical differences between catamenial and non-catamenial TERP. METHODS: The clinical and pathological data in female patients who underwent video-assisted thoracoscopic surgery at the Pneumothorax Research Center during an 8-year period were retrospectively reviewed. This study included 150 female patients with surgico-pathologically confirmed TERP. The subjects were divided into two groups, those having all of the pneumothorax episodes in the catamenial period (CP group) and those who did not (non-CP group). We compared the clinical characteristics and surgico-pathological findings between these two groups. RESULTS: Of the 150 TERP patients, 55 (36.7%) were classified in the CP group, and 95 (63.3%) in the non-CP group. In regard to the locations of endometriosis, all TERP patients had diaphragmatic endometriosis, while pleural implantation was recognized in 34 of the 55 (61.8%) patients in the CP group and 42 of the 95 (44.2%) patients in the non-CP group (P < 0.05). CONCLUSIONS: A significant difference in the proportion of patients with pleural endometriosis was observed between catamenial and non-catamenial TERP. The ectopic sites of the endometriosis may be responsible for the timing of the pneumothorax episodes.