Microwave Scissors-Based Sutureless Laparoscopic Partial Nephrectomy Versus Conventional Open Partial Nephrectomy in a Porcine Model: Usefulness and Complications.

BACKGROUND: This study aimed to compare the benefits and safety of microwave scissors-based sutureless laparoscopic partial nephrectomy (MSLPN) with those of conventional open partial nephrectomy (cOPN). METHODS: Each kidney in nine pigs underwent MSLPN using microwave scissors (MWS) via transperitoneal laparoscopy or cOPN via retroperitoneal open laparotomy. The kidney's lower and upper poles were resected under temporary hilar-clamping. The renal calyces exposed during renal resections were sealed and transected using MWS in MSLPN and were sutured in cOPN. For MWS, the generator's power output was 60 W. Data on procedure time (PT), ischemic time (IT), blood loss (BL), normal nephron loss (NNL), and extravasation during retrograde pyelogram were compared between the two techniques. RESULTS: The authors successfully performed 22 MSLPNs and 10 cOPNs. Compared with cOPN, MSLPN was associated with significantly lower PT (median, 9.2 vs 13.0 min; p = 0.026), IT (median, 5.9 vs 9.0 min; p < 0.001), BL (median, 14.4 vs 38.3 mL; p = 0.043), and NNL (median, 7.6 vs 9.4 mm; p = 0.004). However, the extravasation rate was higher in the MSLPN group than in the cOPN group (54.5 % [n = 12] vs 30.0 % [n = 3]), albeit without a significant difference (p = 0.265). Pelvic stenosis occurred in one MSLPN procedure that involved deep lower pole resection near the kidney hilum. CONCLUSIONS: The study data show that MSLPN can improve intraoperative outcomes while reducing technical demands for selected patients with non-hilar-localized renal tumors. However, renal calyces, if violated, should be additionally sutured to prevent urine leakage.

Comparison of off-clamp microwave scissors-based sutureless partial nephrectomy versus on-clamp conventional partial nephrectomy in a canine model.

Objectives: To compare the usefulness and safety of off-clamp microwave scissors-based sutureless partial nephrectomy (MSPN) with on-clamp conventional partial nephrectomy (cPN) in dogs. Methods: We performed off-clamp MSPN using microwave scissors (MWS) in six dogs, and on-clamp cPN in three dogs, in two-stage experiments. The bilateral kidney upper poles were resected via a midline incision under general anesthesia. After 14 days of follow-up, the lower pole resections were performed. The renal calyces exposed during renal resections were sealed and transected using MWS in off-clamp MSPN and were sutured in on-clamp cPN. In the off-clamp MSPN group, the generator's power output of MWS was set as either 50 W or 60 W for each kidney side. We compared the procedure time (PT), ischemic time (IT), blood loss (BL), and normal nephron loss (NNL) between the two techniques using the Mann-Whitney U-test. Results: We successfully performed 24 off-clamp MSPNs and 12 on-clamp cPNs. The off-clamp MSPN was significantly superior to on-clamp cPN in avoiding renal ischemia (median IT, 0 min vs. 8.6 min, p < 0.001) and reducing PT (median PT, 5.8 min vs. 11.5 min, p < 0.001) and NNL (median NNL, 5.3 mm vs. 6.0 mm, p = 0.006) with comparable BL (median BL, 20.9 ml vs. 23.2 ml, p = 0.804). No bleeding and major urine leakage were noted during the reoperations. Conclusions: Off-clamp MSPN outperforms on-clamp cPN in lowering the risks of postoperative renal function impairment in dogs.

Feasibility of Microwave Scissors-Based Off-Clamp Laparoscopic Partial Nephrectomy in a Porcine Model.

OBJECTIVES: To assess the feasibility of off-clamp laparoscopic partial nephrectomy using microwave scissors. METHODS: We performed transperitoneal laparoscopic partial nephrectomy, without hilar clamping or renorrhaphy, using only microwave scissors for renal resection in a porcine model. For each kidney, 2 types of procedures were performed: a middle pole resection excising an area of 2-cm diameter and approximately 1-cm depth and a lower pole resection at the level of the lower polar line. The renal calyces exposed during renal resection were sealed and transected using microwave scissors. After 3 days of follow-up, the pigs were reoperated to inspect for postoperative complications. Euthanasia was performed to collect the remaining kidneys for histopathological examination. RESULTS: Ten procedures were successfully performed, without hilar clamping or suturing of the renal calyces and parenchyma, in 5 kidneys from 3 pigs. The median resecting time, blood loss, and lateral thermal injury were 23.2 min, 47.1 mL, and 6.8 mm in the middle pole resection, and were 15.1 min, 26.5 mL, and 6.9 mm in the lower pole resection, respectively. No complications were noted during reoperation, such as postoperative hemorrhage and major urine leakage. Extravasation occurred in 2 middle pole resections and 3 lower pole resections during retrograde pyelogram. Hematoxylin and eosin staining revealed thermal injury characterized by tissue microwave fixation in the near zone and acute coagulative necrosis in the intermediate zone. CONCLUSIONS: Microwave scissors-based off-clamp laparoscopic partial nephrectomy is feasible in pigs and can be used for clinical applications.

Feasibility of Microwave-Based Scissors and Tweezers in Partial Hepatectomy: An Initial Assessment on Canine Model.

Purpose: This study aimed to assess the feasibility of partial hepatectomy (PH) simplified by using microwave-based devices in animal experiments. Methods: PH was performed on 16 beagles using either Acrosurg Scissors (AS) or Acrosurg Tweezers (AT) without hepatic pedicle (HP) control. Parenchymal transection time, Glissonean pedicle (GP) seal time, bleeding volume, bile leak, and burst pressure were recorded. Probable complications were investigated after 4 weeks. Results: Transection time (6.5 [6.0-7.6] vs. 11.8 [10.5-20.2] min, p < 0.001) with AT were significantly shorter than with AS. GP sealing times (60 [55-60] vs. 57 [46-91] s, p = 0.859) by both devices were nearly similar. Bleeding volume in the AT group was approximately one-fourth of that in the AS group (6.7 [1.4-22] vs. 28.8 [5.8-48] mL, p = 0.247). AT created higher burst pressure on the bile duct stumps (p = 0.0161). The two devices did not differ significantly in morbidity and mortality after four-week follow-up. Conclusion: Acrosurg devices achieved a safe PH without HP control owing to microwave-based sealing. AS could be used alone in PH, whereas the clamp-crushing function of AT seemed more advantageous in reducing the transection time and blood loss.

Functional Evaluation of a Novel Microwave Surgical Device in a Canine Splenectomy Model.

Aim: Partial splenectomy remains a difficult procedure even with the assistance of a sealing system. Recently, a scissor-like microwave energy device (Acrosurg) that provides seamless coagulation and manual cutting has been applied in surgery. The objective of this study is to evaluate the surgical capabilities of Acrosurg in partial splenectomy. Materials and Methods: Acrosurg and Harmonic Focus (HF) were employed for partial splenectomy in dogs without prior ligation of vessels. Cutting time, cutting area, and bleeding were recorded. Lateral thermal injury (LTI), possible complications was observed immediately and after 4 weeks. Results: The manual cutting mechanism of Acrosurg required a longer cutting time compared with the automatic cutting mode of HF (301.5 [243.2-527] vs. 114.5 [106.0-135.0] sec, p < 0.01). There was no statistical difference in cutting area or bleeding cases. Acrosurg achieved complete hemostasis in all cases, whereas the HF group failed to stop bleeding in two of the eight cases. The Acrosurg group exhibited a similar LTI compared with the HF group (3.0 [2.4-3.4] vs. 2.7 [2.3-2.9] mm, p = 0.151), but the LTI of the Acrosurg group tended to shrink more after 4 weeks (1.2 [1.0-1.3] vs. 1.7 [1.3-1.9] mm, p < 0.05). Conclusions: A microwave energy device enabled a partial splenectomy without vessel ligation. The combination of manual cutting and sealing capability helps not only provide an appropriate seal time by adjusting cutting timing adaptively but also potentially stop bleeding by using a microwave heating process unlike other energy devices.

Vessel-Sealing Capability of Novel Microwave Sealer: Experimental Study in Animal Models.

Background. Ultrasonically activated dissectors (UADs) and radiofrequency-based devices have been considered excellent surgical devices because of their reliability and flexibility. Meanwhile, microwave-based devices have demonstrated potential with their unique heating mechanism. This study aims to compare the sealing function of a newly invented forceps-like microwave sealer (MS) with that of currently available UADs. Materials and Methods. MS and 2 examples of UADs (Harmonic Focus+ [HF+] and Sonicision [SNC]) were employed to perform mesenterectomies (in vivo) and sealing sizable vessels (ex vivo). Vessel diameter, seal time, burst pressure (BP), sealing completion, and instrument sticking were recorded. The samples underwent histological investigation for thermal damage evaluation. Results. During mesenterectomies, MS required 3 seconds and 30 W to secure a complete seal. The BP achieved by the MS seal was higher than that of HF+ and SNC on arteries (851 ± 203.7 vs 682.4 ± 287.3, P < .05; vs 833.1 ± 251.2 mmHg, P = .4523, respectively) but was not statistically different on veins (324.9 ± 203.5 vs 460.1 ± 320.3 vs 508.3 ± 350.7 mmHg, P = .215). In all trials, MS caused less sticking but exhibited similar heat-induced alterations to UADs. MS's thermal spread was not statistically more extended than that of UADs on either arteries or veins. Conclusions. MS was capable of not only sealing tiny vessels but also achieving high-pressure endurance on sizable vessels. Its forceful grasping and synchronous heating process helped create solid stumps with an acceptable thermal spread.

Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios.

Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among Hylobates spp., Ateles sp., and Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure.

Magnetic resonance and ultrasound image-guided navigation system using a needle manipulator.

PURPOSE: Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is preferable due to its superior soft tissue contrast. The objective of this study was to develop and evaluate an MR and US multi-modal image-guided navigation system with a needle manipulator to enable US-guided applicator placement during MR imaging (MRI)-guided percutaneous tumor ablation. METHODS: The MRI-compatible needle manipulator with US probe was installed adjacent to a 3 Tesla MRI scanner patient table. Coordinate systems for the MR image, patient table, manipulator, and US probe were all registered using an optical tracking sensor. The patient was initially scanned in the MRI scanner bore for planning and then moved outside the bore for treatment. Needle insertion was guided by real-time US imaging fused with the reformatted static MR image to enhance soft tissue contrast. Feasibility, targeting accuracy, and MR compatibility of the system were evaluated using a bovine liver and agar phantoms. RESULTS: Targeting error for 50 needle insertions was 1.6 ± 0.6 mm (mean ± standard deviation). The experiment confirmed that fused MR and US images provided real-time needle localization against static MR images with soft tissue contrast. CONCLUSIONS: The proposed MR and US multi-modal image-guided navigation system using a needle manipulator enabled accurate needle insertion by taking advantage of static MR and real-time US images simultaneously. Real-time visualization helped determine needle depth, tissue monitoring surrounding the needle path, target organ shifts, and needle deviation from the path.

The invention of microwave surgical scissors for seamless coagulation and cutting.

PURPOSE: We developed a microwave energy-based scissors device (MWCX) that is capable of performing cutting and coagulation using 2.45 GHz microwave energy. This paper aims to present the concept of the device and assess the basic functions including the hemostasis, cutting, and sealing abilities. METHODS: Seven beagle dogs were used in our experiments. In six dogs, we measured the coagulation time (CT), lateral thermal injury (LTI), bursting pressure (BP). The dogs were then subjected to re-laparotomy 1 week later to allow us to investigate the results. In one dog, the same factors and the quantities of smoke and mist emitted were compared to those observed when using a Harmonic Focus (HF) device. RESULTS: At 60 W, the MWCX could cut and seal small (5 s, diameter 1-2 mm) and medium-sized (10 s, 3-4 mm) vessels with complete hemostasis. The liver (length 2 cm) was cut for 30 s. Harvested vessels were sealed for 10 s (artery, 17 times; vein, six times). The mean BP was 887. 8 ± 41.5 mmHg in the medium arteries and 457.2 ± 118.0 mmHg in veins, with a mean diameter of 4.5 ± 1.3 mm. In a comparative study, the MWCX showed similar results to the HF with regard to the CT, BP and LTI, and emitted less smoke and mist. CONCLUSION: The MWCX showed similar levels of functionality and safety to HF, as well as the advantages offered by the use of microwave energy. Microwave devices might be used in the majority of applications for which traditional energy devices are used.

[A Case of Gastric Cancer Underwent Two-Stage Gastrectomy after Chemotherapy-Induced Perforation].

A 70's man presenting with a chief complaint of stomachache was found to have advanced gastric cancer with a deep ulcer and some lymph-node metastases. We decided performing a curative operation after 2 courses of S-1 plus cisplatin. On the first course day 13 of chemotherapy, he complained of severe epigastralgia, and we diagnosed as generalized peritonitis due to perforation of gastric cancer. We performed an urgent laparoscopic operation, which made perforation simple closure and omentopexy. Curative distal gastrectomy with D2 lymph node dissection was successfully performed on postoperative day 16.

Feasibility and safety of hyperthermic intraperitoneal chemotherapy using 5-fluorouracil combined with cisplatin and mitomycin C in patients undergoing gastrectomy for advanced gastric cancer.

BACKGROUND AND OBJECTIVES: We conducted a dose-finding study for 5-fluorouracil (5-FU) administered with cisplatin (CDDP) and mitomycin C (MMC) to find an improved regimen for hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced gastric cancer (GC). METHODS: The appropriate HIPEC regimen previously determined in vitro was 5-FU (200 µg/mL), MMC (2 µg/mL), and CDDP (10 µg/mL) at hyperthermic conditions (42°C) for 30 min. This was a clinical study to determine the recommended dose of 5-FU in combination with MMC and CDDP at 42°C for 30 min and to evaluate HIPEC safety in patients at high risk of developing peritoneal metastases following GC surgery. RESULTS: Twelve patients were treated with surgery plus HIPEC using 5-FU at 0, 500, 750, and 1000 mg combined with MMC (10 mg) and CDDP (50 mg) in the perfusate (5 L). Dose-limiting toxicities did not develop until 1000 mg 5-FU was reached. Four patients experienced grade 1 or 2 adverse events. The recommended dose was 1000 mg 5-FU/5 L perfusate. Eight (66.7%) patients demonstrated no recurrence of peritoneal metastases; 5-year overall survival rate was 83.3%. CONCLUSION: Gastrectomy and HIPEC with MMC, CDDP, and 5-FU is feasible, safe, and may protect against peritoneal metastasis following surgery for advanced GC.

Predictive detection areas for identifying additional MRI-detected breast lesions on second-look ultrasonography.

PURPOSE: Identifying an additional MRI-detected breast lesion on second-look ultrasonography (US) is technically challenging because of lesion displacement with the patient's position change. The aim of this study is to help identify MRI-detected lesions on second-look US by developing a probing area, called "the predictive detection area" (PDA), and by assessing the PDA. METHODS: We measured the nipple-to-lesion distances (NLDs) for 16 breast lesions on prone- and supine-position MRI sets and calculated the difference and angle between the two NLD vectors, representing the lesion displacement. The minimum and maximum differences and angles were chosen to form the PDA. Another 22 breast lesions, detected in the prone MRI, were identified on US by probing the PDA to evaluate the probability of existence. RESULTS: The width between the minimum and maximum differences in two NLDs and the angle to form the PDA for the upper-inner, upper-outer, and lower-outer quadrants were 23.0 mm and 95.0°, 29.0 mm and 41.0°, and 18.0 mm and 17.0°, respectively. The respective probabilities of existence were 100, 80, and 100%. CONCLUSIONS: The PDA had a high probability of existence and was acceptably accurate; therefore, the PDA in a second-look US has the potential to help operators to quickly identify additional MRI-detected lesions.

ABCG2 expression in colorectal adenocarcinomas may predict resistance to irinotecan.

Irinotecan is a key drug for patients with advanced and recurrent colorectal carcinoma. However, the efficacy of irinotecan is not sufficient; partly, as there is no useful marker to predict chemosensitivity to the drug. The aim of the present study was to evaluate whether the expression levels of adenosine triphosphate-binding cassette sub-family G (WHITE) member 2 (Junior blood group) (ABCG2) in primary colorectal tumors predict chemoresistance to irinotecan. Using the resected primary tumor specimens of 189 patients with colorectal cancer, the association between the immunohistochemical expression of ABCG2 protein and the results of the collagen gel droplet embedded culture drug sensitivity test, performed to evaluate the chemosensitivity to SN-38 (an active metabolite of irinotecan), was investigated. Among the 189 patients, 17 received irinotecan-based chemotherapy, and their responses and progression-free survival (PFS) were analyzed. The tumors of patients with increased ABCG2 expression accounted for 60% of the tumors examined, and were significantly more resistant to SN-38, compared with patients with low ABCG2 expression (P<0.001). In a multivariate logistic regression analysis, increased expression of ABCG2 protein was an independent and significant predictor of resistance to SN-38, increasing the risk of resistance by 12-fold. Increased expression of ABCG2 and a low sensitivity to SN-38 was significantly associated with resistance to irinotecan-based chemotherapy (P=0.01 and 0.028, respectively). The median PFS of patients with increased expression of ABCG2 was significantly shorter, compared with patients with low expression levels of ABCG2 (104 vs. 242 days; P=0.047). The increased immunohistochemical expression of ABCG2 in primary tumors may be a useful predictive biomarker of resistance to irinotecan-based chemotherapy for patients with recurrent or metastatic colorectal cancer.

Lymphoepithelial cyst with sebaceous glands of the pancreas: a case report.

BACKGROUND: Lymphoepithelial cyst (LEC) of the pancreas is a rare benign tumor. LEC with sebaceous glands of the pancreas is extremely rare, and its histogenesis remains unclear. CASE PRESENTATION: We present a 66-year-old man with an incidental finding of a cystic lesion at the neck of the pancreas. Pancreatic juice cytology results and elevated serum carbohydrate antigen 19-9 and Dupan-2 levels indicated that the cyst was a potential adenocarcinoma. Therefore, a pancreaticoduodenectomy was performed. Macroscopically, the tumor was a unilocular cyst with a thin transparent wall, filled with soft yellow material. Pathological findings showed that the cyst was lined with squamous epithelium, accompanied by dense lymphoid tissue with scattered germinal centers. There were no hair follicles, but sebaceous glands were present in the lymphoid tissue just beneath the squamous epithelium. Therefore, the histopathological diagnosis was an LEC with sebaceous glands of the pancreas. Furthermore, the squamous epithelium surrounding the cyst was pathologically continuous with the tubular structure, indicating that the tubular structure transitioned into the squamous epithelium. CONCLUSIONS: We report an extremely rare case of LEC with sebaceous glands of the pancreas. Moreover, the pathological findings, which showed that the tubular structure transitioned into the squamous epithelium, suggested that this was squamous metaplasia. In order to investigate the histogenesis of LEC of the pancreas, the pathological findings must be evaluated.

Thermal tissue change induced by a microwave surgical instrument in a rat hepatectomy model.

BACKGROUND: Microwaves exhibit great potential in tissue heating, which causes effective coagulation. Using this energy, we have developed the microwave coagulation surgical instrument (MWCX) for clinical application. Here, we characterized the impact of MWCX on tissues including heating property, tissue change, and spread of thermal injury. METHODS: Hepatectomy was performed with MWCX using a rat model. The resections were completed using various energy levels and powers. Tissue temperature during radiation was recorded. Tissue change and lateral thermal injury (LTI) was assessed immediately, 7 days, 3 months, and 6 months after resection. RESULTS: All cutting and hemostasis procedures were successfully accomplished. Major histologic findings consisted of deformation or destruction of hepatocytes, tissue edema, and peripheral hemorrhage. At various energy levels, 200 to 1000 J, the tissue was heated up to approximately 80°C to 140°C causing 2.7- to 6.5-mm LTI on the 7th day. LTI was then decreased gradually in the following term. At certain energy levels, the application of neither 20 W nor 40 W induced significant difference in both heating and LTI. CONCLUSIONS: MWCX achieved effective tissue coagulation with relevant tissue injury, and it should be a good candidate for clinical application.

[Stage IV Gastric Cancer with Positive Peritoneal Washing Cytology or Peritoneal Dissemination Was Successfully Treated with Gastrectomy and Hyperthermic Intraperitoneal Chemotherapy(HIPEC)Followed by Systemic Chemotherapy - A Report of Two Cases].

Survival of Stage IV gastric cancer is poor. We report 2 cases of Stage IV gastric cancer with positive peritoneal washing cytology or peritoneal dissemination that were successfully treated with gastrectomy and hyperthermic intraperitoneal chemotherapy( HIPEC)followed by systemic chemotherapy. Case 1: A 59-year-old woman. She was diagnosed with advanced gastric cancer and underwent gastrectomy with HIPEC. Her peritoneal washing cytology was positive during the gastrectomy. After the surgery, she underwent chemotherapy consisting of 8 courses of combination S-1 plus CPT-11 and 19 courses of PTX. It has been 5 years and 7 months since she had the surgery and she survives without recurrence of the cancer. Case 2: A 60-year-old woman. She was diagnosed with advanced gastric cancer and peritoneal dissemination(peritoneal cancer index: 3 points). She underwent gastrectomy, hemi-colectomy, and HIPEC. After the surgery, she underwent chemotherapy, 35 courses of combination S-1 plus PSK/DOC, and 13 courses of S-1 plus PSK. It has been 5 years since her surgery and she survives without exacerbation of the cancer. These cases suggest a gastrectomy and HIPEC followed by systemic chemotherapy may represent an effective treatment for advanced gastric cancer with a small amount of peritoneal metastasis.

[Salvage Surgery after CRT for Advanced Esophageal Cancer Resulting in a Pathological Complete Response and More Than Five Years' Survival].

A 62-year-old woman visited our hospital because of dysphagia. She was diagnosed with upper-middle esophageal type 4 cancer, which was 9 cm in length, according to the results of endoscopy. Squamous cell carcinoma was demonstrated using endoscopic biopsy. A CT scan revealed that the tumor had directly invaded into the trachea(cT4). Chemoradiotherapy(CRT) (5-FU and CDDP with 50 Gy of radiation)was administered. Although CT after CRT resulted in shrinkage of the tumor and no further tracheal invasion, esophageal stenosis remained. Therefore, salvage surgery(subtotal esophagectomy with 3-field lymph node dissection)was performed. Pathologically, no carcinoma cells were found in the resected specimen and a com- plete response(grade 3)was diagnosed. The patient received adjuvant chemotherapy(tegafur/uracil at 300mg/day per os) for 1 year. The patient is alive with no relapse of carcinoma more than 5 years after the first treatment.