Erbium-doped-fiber-based broad visible range frequency comb with a 30 GHz mode spacing for astronomical applications

Optical frequency combs have the potential to improve the precision of the radial velocity measurement of celestial bodies, leading to breakthroughs in such fields as exoplanet exploration. For these purposes, the comb must have a broad spectral coverage in the visible wavelength region, a wide mode spacing that can be resolved with a high dispersion spectrograph, and sufficient robustness to operate for long periods even in remote locations. We have realized a comb system with a 30 GHz mode spacing, 62 % available wavelength coverage in the visible region, and 40 dB spectral contrast by combining a robust erbium-doped-fiber-based femtosecond laser, mode filtering with newly designed optical cavities, and broadband-visible-range comb generation using a chirped periodically-poled LiNbO3 ridge waveguide. The system durability and reliability are also promising because of the stable spectrum, which is due to the use of almost all polarization-maintaining fiber optics, moderate optical power, and good frequency repeatability obtained with a wavelength-stabilized laser.Comment: 19 pages, 5 figure

Delayed healing at free ALT donor site

Background The free anterolateral thigh (ALT) flap has been widely used for various kinds of reconstructions. However, delayed healing at the donor site occasionally occurs due to wound dehiscence or the partial loss of grafted skin at the donor site. The aim of the present study was to identify reliable predictive factors for delayed healing at the donor site after the harvest of a free ALT flap. Methods This study included 52 patients who underwent reconstructive procedures using free ALT flaps. The delayed healing group included patients with wounds at the donor site that had not healed over 3 weeks after surgery, and the normal healing group included patients who showed wound healing within 3 weeks after surgery. Multivariate logistic regression models were created to identify the risk factors for delayed healing at the ALT flap donor site. Results Among the 52 patients, 24 (46.2%) showed delayed healing at the donor site, and 6 patients required additional operative treatment. A high preoperative body mass index (BMI), smoking, and skin grafting were found to be significantly associated with delayed healing at the ALT donor site. Of the 37 patients who underwent skin grafting, 23 (62%) experienced delayed healing at the donor site. Conclusions A high preoperative BMI, smoking, and skin grafting were risk factors for delayed healing at the free ALT donor site. Skin grafting at the ALT donor site should be avoided in patients with a high BMI or a habit of smoking

Limb salvage and vascular augmentation by microsurgical free flap transfer for treatment of neuropathic diabetic foot ulcers

Background : Neuropathic diabetic foot ulcers are generally deep and infectious wounds extending to the bone or joint. We performed microsurgical free flap transfer for limb salvage and vascular augmentation of feet with diabetic neuropathy. Methods : Angiography was performed to identify any significant arterial disease. The free flaps were transplanted after resection of the damaged skin and infected bone. Flow-through or end-to-side anastomosis to the dorsalis pedis artery was performed to preserve the arterial blood flow to the residual foot. Results : An anterolateral thigh flap and free flaps based on the subscapular artery system were transplanted in 1 and 10 patients, respectively. All flaps survived. Arterial flow on the distal side of the anastomosis was postoperatively confirmed in all patients. During a mean follow-up period of 52 months, the long-term complications observed were recurrent ulcers in 4 patients. The limb salvage rate was 100%, and 82% of patients achieved functional ambulation. Conclusions : Microsurgical flap transplantation is a safe and useful technique for minimal amputation of a diabetic neuropathic foot. Postoperative protection of the feet is important in order to avoid recurrence of foot ulceration. The use of protective footwear custom-tailored for each patient is strongly recommended

Quantitative analysis of hemodynamics of congested island flaps under leech therapy

Background A congested flap is a good indication for leech therapy. However, determining the appropriate number of leeches as well as the appropriate application time in clinical cases is difficult. We analyzed hemodynamics in rabbit island flaps under leech therapy to find a suitable clinical procedure for determining the appropriate number of leeches to be used and the duration of therapy. Methods Island flaps were raised in 35 rabbit ears, and congestion was induced by venous clamping. Treatment involved use of 1 or 3 leeches and was begun 60 minutes after venous occlusion. Flaps were examined for area of surviving tissue, alterations in transcutaneous oxygen and carbon dioxide tension (TcPO2 and TcPCO2), and flow volume. Arteriole and venule diameters and flow velocities were examined microscopically. Results Flap survival area in the 3-leech therapy group was significantly larger than the 1-leech therapy group and the control group. With 3- leech therapy, TcPCO2 decreased significantly, as did arteriole and venule diameters. After clamp release, TcPCO2 and venule diameter continued to decrease in this group, and flow velocity increased significantly. Conclusions Leech therapy may salvage compromised flaps by replacing congested blood with new arterial blood and thus maintaining flap viability. TcPO2 and TcPCO2 monitoring may help evaluate the therapeutic effect and determine the appropriate number of leeches to apply and the duration of therapy

Quantitative analysis of hemodynamics of congested island flaps under leech therapy

Background A congested flap is a good indication for leech therapy. However, determining the appropriate number of leeches as well as the appropriate application time in clinical cases is difficult. We analyzed hemodynamics in rabbit island flaps under leech therapy to find a suitable clinical procedure for determining the appropriate number of leeches to be used and the duration of therapy. Methods Island flaps were raised in 35 rabbit ears, and congestion was induced by venous clamping. Treatment involved use of 1 or 3 leeches and was begun 60 minutes after venous occlusion. Flaps were examined for area of surviving tissue, alterations in transcutaneous oxygen and carbon dioxide tension (TcPO2 and TcPCO2), and flow volume. Arteriole and venule diameters and flow velocities were examined microscopically. Results Flap survival area in the 3-leech therapy group was significantly larger than the 1-leech therapy group and the control group. With 3- leech therapy, TcPCO2 decreased significantly, as did arteriole and venule diameters. After clamp release, TcPCO2 and venule diameter continued to decrease in this group, and flow velocity increased significantly. Conclusions Leech therapy may salvage compromised flaps by replacing congested blood with new arterial blood and thus maintaining flap viability. TcPO2 and TcPCO2 monitoring may help evaluate the therapeutic effect and determine the appropriate number of leeches to apply and the duration of therapy

Flap Monitoring by TcPCO2

Background: Measurement of transcutaneous oxygen pressure (TcPO2) and transcutaneous carbon dioxide pressure (TcPCO2) has been used for free flap monitoring. Because these values are obtained with sensor probes heated to 44°C, there is potential for low-temperature burns on skin flaps. We measured TcPO2 and TcPCO2 at 37°C in both animals and humans to determine the feasibility and safety of the procedure as a postoperative flap monitoring method. Methods: Twelve epigastric island flaps were elevated in rabbits, and TcPO2 and TcPCO2 were measured at 37°C before and after ligation of the pedicles. In addition, TcPO2 and TcPCO2 at 37°C were measured in healthy men. Subsequently, the method was applied to postoperative monitoring of free flaps in 49 clinical cases. Results: TcPO2 and TcPCO2 values were significantly affected by the experimental flap elevation. A rapid increase in TcPCO2 was observed with both arterial and venous occlusion. In the healthy men, TcPO2 and TcPCO2 were measurable at all skin surface sites. In the clinical cases of free flap transfer, TcPO2 values remained very low for at least 72 hours. TcPCO2 values ranged from 40 to 70 mmHg for 72 hours in more than 80% of cases. In 2 cases, TcPCO2 values increased to more than 90 mmHg, and exploration surgery was performed. These compromised flaps were saved by reanastomosis of the veins. Conclusions: Continuous monitoring of TcPCO2 at 37°C can provide objective information and alert doctors and nurses to the need for checking the free flap

Three-dimensional sodium chloride (NaCl) model for simulated mandibular reconstruction surgery : a new environmentally friendly material

Background : Mandibular reconstruction using a fibular graft is a difficult procedure that requires technical expertise to enable adequate occlusal function and restore an aesthetic appearance. Here we used three-dimensional (3D) sodium chloride (NaCl) models for simulated mandibular reconstruction surgery. This study aimed to reveal the accuracy of mandibular reconstruction with fibular grafts using this model. Methods : Mandibular reconstructions using 3D NaCl models were performed in 5 cases. The maxilla, mandible, and fibular models were developed using computed tomography (CT) data. We performed preoperative cutting and simulation surgery using this model. Angles between the body of the corpus and symphysis were measured from the axial view (n = 4). Angles between the ramus and the body of the corpus were measured from the lateral and axial views (n = 6). These angles were measured on simulated models and postoperative CT images were compared. Results : Differences between the angles measured on the simulated models and postoperative CT images were 0-5°(mean, 1.9°). Conclusions : We were able to reproduce the neomandibles with precise osteotomies using the 3D NaCl models. We believe that simulated mandibular reconstruction surgery using this model might help reduce the number of intraoperative neomandibular segment adjustments

Reduction mammaplasty and mastopexy for the contralateral breast after reconstruction surgery following cancer resection : A report of 3 cases

Background : Breast reconstruction generally involves autologous tissue transplantation and placement of a mammary prosthesis. When the patient’s breasts are extremely large and ptotic, breast reconstruction often results in significantly asymmetrical appearance. However, a good aesthetic outcome after reconstruction surgery following cancer resection is an important quality-of-life factor. We evaluated the efficacy of touch-up surgery, either reduction mammaplasty or mastopexy, performed on the contralateral breast for symmetrization. Methods : Reduction mammaplasty was performed on the contralateral breast in 2 patients and mastopexy was performed on the contralateral breast in 1 patient after reconstruction surgery following cancer resection, between 2008 and 2014. We reviewed each patient’s medical record for general clinical information and for the methods of breast cancer resection and breast reconstruction used, wait time between breast cancer resection and touch-up surgery, preservation of the sensitivity of the nipple-areola complex after the touch-up surgery, and aesthetic outcome (based on visual analog scale score). Results : Wait times in the 3 cases were 4, 9, and 18 months. Nipple-areolar sensitivity was well preserved in all 3 cases. Aesthetic outcomes were judged “excellent” or “very good.” Conclusion : Revision surgery on the contralateral breast 4 to 18 months after breast reconstruction substantially improves the aesthetic outcome