Using the bovine liver and experimental deep electrodes, we investigated the coagulation effect in ischemic livers in an attempt to increase the range of coagulation of the deep electrodes. The hepatic blood flow was obstructed by blocking the hepatic artery (A), the portal vein (P), or both the hepatic artery and portal vein (AP), and for comparison, coagulation was performed without blocking the hepatic blood flow (C) in control animals. Two electrodes were used for microwave coagulation ; a 1.6-mm shell-type deep electrode (shell-type), and a 3-mm experimental electrode (30 NL). After coagulation, each sample was fixed in 10% formalin and sliced for histological examination. There was a brown boundary area between the coagulated and non-coagulated areas.
When the hepatic blood flow was not blocked and coagulation was performed using the shell-type deep electrode at 60W for 2 minutes, a brown boundary area of 1 to 3 mm was seen. The internal diameter of the coagulated area was 23 × 11 mm, and its external diameter including the brown boundary area was 26 × 16 mm. When the hepatic artery or the portal vein was blocked to obstruct the hepatic blood flow, the internal diameter of the coagulated area was 51 × 20 mm, and its external diameter was 56 × 34 mm. Furthermore, on using the 30 NL electrode was used for coagulation at 60W for 2 minutes, the maximum internal and external diameters of the coagulated areas were 25 × 16 and 34 × 27 mm, respectively, when the hepatic blood flow was not blocked (C), 27 × 19 and 35 × 29 mm, respectively, when the hepatic artery was blocked (A), 24 × 21 and 35 × 34 mm, respectively, when the portal vein was blocked (P), and 27 × 26 and 68 × 50 mm, respectively, when the hepatic artery and portal vein were blocked (AP). This indicated that the brown boundary area increased when the portal vein was blocked, and when the hepatic artery and portal vein were blocked, the diameter of the coagulated areas was about twice as big as that without blocking the hepatic blood flow. HE-staining of the cross sections of boundary areas showed shrunken nuclei and intercellular hemorrhagic changes. This suggested that a 3-cm hepatic tumor can be controlled by a single microwave coagulation inserting the experimental electrode into the center of the tumor while blocking the hepatic blood flow.

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Hepatic resection using microwave tissue coagulator have often been performed for liver malignant tumor in adults. But usefulness and safety about hepatic resection in children have not been established. In four cases (2 males and 2 females ) of liver malignant tumor in children, we performed hepatic resection using MTC, and evaluated postoperative complication, blood loss during operation and period of drainage. In all cases, postoperative courses were smooth and any severe complications did not developed. The blood loss were less than 20 ml/kg except one case who had tumor thrombosis in the right portal vein and average period of drainage was 19.5 days.
One case who had multiple lesions and tumor thrombus died 6 months after operation, but other cases are alive now with no evidence of recurrence in follow up period rainging from 41 to 52 months. Hepatic resection using MTC is thus considered to be a useful and safe method for malignant liver tumor in children.

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In percutaneous microwave coagulation therapy (PMCT), it is important to understand the three-dimensional anatomy of a hepatic tumor in order to allow careful aiming and sufficient tissue coagulation. Therefore, the effectiveness of PMCT under general anesthesia was examined. When PMCT was performed under general anesthesia, insertion and tissue coagulation could be performed safely even for the tumors in which percutaneous aiming is difficult, such as those in the caudate lobe or under the diaphragm. Pain was complained of by 5.8% of the patients treated under general anesthesia and 70% of those treated under local anesthesia. Portal thrombosis, biliary stenosis, and gastric and intestinal wall injury by the probe tended to occur more frequently in those treated under local anesthesia. The number of days in hospital after starting therapy was 6.9 ± 3.1 days for patients treated under general anesthesia, while it was 8.1 ± 6.6 days for those treated under local anesthesia.

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Percutaneous microwave coagulation therapy (PMCT) was performed on 31 patients with hepatocellular carcinoma (HCC) smaller than 3 cm in diameter (average 2 cm). According to Child classification, 14 patients were in the Child grade A, 15 in the Child grade B, and 2 in the Child grade C. The 1-, 2- year survival rates were 100%, 88%. Local recurrences in the advanced nodules were more often observed than in the early nodules. Major complications of the treatment were peritoneal bleeding in two patients and subcapsular liver hemorrhage in one patient. PMCT seems to be a valuable percutaneous local treatment for small HCC.

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PMCT treated 92 times on 49 nodules in 43 cases of hepatocellular carcinoma was clinically investigated. The tumor marker rapidly decreased after PMCT, however no great change in the tumor diameter was confirmed. Though the liver function test, WBC count, and CRP exhibited transient changes after PMCT, a tendency for these to return to pre-PMCT values 1 wk after PMCT was confirmed. Complications observed were one case each of Biloma, pneumothorax, pleuritis, and burn scars on the abdominal wall, though each were conservatively recovered. Only 1 case of local recurrence was observed out of 36 cases on which radical PMCT was treated. If PMCT is adequately performed on small hepatocellular carcinoma, a considerably favorable effect is observed in terms of local control of tumor.

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The possible use of percutaneous transhepatic microwave tissue coagulation therapy (PMCT) using ultrasonography under local anesthesia for small solitary hepatocellular carcinoma was studied.
The subjects were 7 patients having primary or reccurent hepatocellular carcinoma with solitary liver tumor less than 3 cm in size, consisting of 4 primary and 3 reccurent hepatocellular carcinoma, PMCT was performed continuously 3 times at the out put of 30 watts for 30 seconds at time. Tumor was completely coagulated by irradiation from 2 to 6 times judged by enhanced CT.
No reccurence of tumor was recognized in the coagulation area. Thus, the results suggest that PMCT is a useful therapy for small hepatocellular carcinoma as a local control.

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We compared the usefulness of percutaneous hot water injection and microwave coagulation therapy (PHMCT) and percutaneous microwave coagulation therapy (PMCT) in patients with hepatocellular carcinomas (HCCs). We performed PHMCT in 18 patients with HCCs (23 nodules) measuring less than 30 mm in diameter and PMCT in 5 patients with HCCs (7 nodules).
After 1 week of treatment, we performed a dynamic computed tomography (CT) scan to examine the maximum area of necrosis. There was significant difference in long and short axes diameter of the necrotic area between the PHMCT group injected hot water with more than 15 ml and the PMCT group. Our findings indicate that PHMCT is an effective treatment for small HCCs.

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A 74-years-old man had a 5 cm in diameter hepatic tumor at S₃ which was diagnosed as hepatocellular carcinoma (HCC). The patient had also old myocardinal infarction, chronic renal failure and arteriosclerosis obliterans, therefore he was excluded from the indication of hepatectomy or transcatheter arterial embolization (TAE). Because the tumor was exposed to the ventral and dorsal surface of the liver, percutaneous ethanol injection therapy (PEIT) had also the risk to bring about ethanol leakage to abdominal cavity. Percutaneous microwave coagulation therapy (PMCT) had also the risk of complications such as bleeding and burn of surrounding organs. Although the tumor was large and located at surface, we performed PMCT, the following by PEIT in order to avoid those complications. In result, these combination therapy reduced the frequency of injection, the total volume of ethanol, and the period of therapy without complications.

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54 patients had liver metastases from colorectal cancer. Microwave Coagulo-necrotic therapy (MCN) for liver metastases from colorectal cancer was performed in 25 patients. The patients with a MCN for liver metastases had a three-year survival rate of 46.6%. The patients of liver metastases with chemotherapy by intrahepatic infusion and with systematic chemotherapy by p.o. had each a three-year survival rate of 0% and 9.6%. For nonresectable liver metastases (H₂, H₃), a three-year survival rate of MCN and chemotherapy was each 39% and 0%. We propose that MCN should be selected for cases of nonresectable liver metastases from colorectal cancer.

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Percutaneous microwave coagulo-necrotic therapy were performed on 5 times of 4 patients with chronic renal failure. They ware 2 metastatic liver carcinomas and 2 hepatocellular carcinomas.
Serum creatinine levels and BUN levels did not indrease after the therapy. In this seriase occured burn injury of skin in one case, but other cases there were no complications.
This therapy seems to useful for the liver tumors with chronic renal failure or high risk patients for the operation.

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Therapeutic effect of percutaneous microwave coagulation therapy was evaluated in nine patients with hepatocellular carcinoma who had been given percutaneous ethanol injection therapy (PEIT) but did not show sufficient effects. Subjects were nine patients with hepatocellular carcinoma diagnosed by biopsy and the major tumor length was between 9 and 42 mm. As a treatment, PEIT was performed first in all the patients. PMCT was performed in the cases in which sufficient amount of ethanol could not be administered due to self-uncontrollable pain and marked drainage of ethanol into vascular system and in those which had residual tumors after PEIT. When effects were judged by dynamic CT or dynamic MRI, tumor necrosis effect was 100% in all the cases and, therefore, the treatment was finished. In the present study, PMCT was performed for the tumor remaining after PEIT and combination of these therapies was considered effective since the residual tumor was small and tumor necrosis effect of 100% was available relatively easily.

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We performed LMC in 58 patients with solitary HCC. Mean tumor size was 24.6 mm (range : 12 to 66 mm) Three cases required postoperative procedures such as PEI or TAE. In 55 cases, HCC was treated by LMC alone. LMC was very effective for HCCs measuring under 4cm in diameter. In most patients, oral intake was started in the evening of the day of LMC. Ambulation was resumed on the day after treatment in all cases. No major complications occurred. The mean postoperative hospital stay in the patients treated by LMC alone was 9.4 days. LMC is minimally invasive and requires only a short convalescence. LMC is excellent in terms of cost / benefit and the quality of life and has great potentiality.

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Thoracoscopic microwave coagulonecrotic therapy (TMCT) have been reported one of the benefit approach for hepatocellular carcinoma (HCC) which located on the subphrenic area of the liver. In this report, TMCT was performed on 3 patients with HCC. They were selected because percutaneous ethanol injection therapy (PEIT), transcatheter arterial embolization (TAE) were not effective and surgical resection could not be done because of hepatic dysfunction. A thoracoscope was introduced into the thoracic cavity through the fifth intercostal space in the midaxillary line, and two other trocars were placed at the 4th intercostal space in the anterior axillary line and 5th intercostal space in the posterior axillary line. TMCT was performed with the guidance of endoscopic ultrasonography (EUS), 1 case was done across the diaphragm and 2 cases were done open the diaphragm. Microwave coagulators with 10 mm diameters, 40 mm in length were used under the condition of output of coagulator at 80 - 100 watts and the duration at 40 - 60 sec. MCT was repeated until the surrounding tissue was unclear by EUS. The effectiveness of the coagulation were ascertain by postoperative enhanced computed tomography.

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For hepatocellular carcinoma (HCC), surgical resection is the optimal treatment, however, the amount of resectable hepatic parenchyma is limited because of liver cirrhosis. We evaluated the advantage of microwave coagulation for liver resection in 16 liver cirrhotic patients. The patients were divided into three groups according to surgical procedures. Group R (n = 5) : patients underwent liver resection without microwave coagulation. Group MR (n = 6) : patients underwent liver resection using microwave coagulation. Group M (n = 5) : patients underwent microwave coagulation therapy with thoracotomy. We compared with Group MR with Group R in operation time, blood loss, postoperative peak GOT and CRP levels. Group MR significantly shortened operation time (p = 0.001), and decreased blood loss during operation (p = 0.008) compared with Group R. These findings suggest that microwave coagulation is useful for liver rection in cirrhotic patients.

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Endoscopic microwave coagulation therapy (EMCT) was applied to female patients aged 79 and 82 with obstructive jaundice due to lower bile duct carcinoma, because of their refusal pancreatoduodenectomy (PD). A single 10-second exposure of microwave (50W, 2450 MHz) was delivered 15 to 20 times during each treatment to the cancerous tissue using a monopoler shielded wire electrode under guidance of a percutaneous cholangioendoscopy. Treatment was repeated a total of three or six times at intervals of 1 week, and an expandable metallic stent was placed after recanalization of bile duct and negative tests for cancer cells. Supplementary radiation therapy (50.4Gy) was performed after EMCT, and no complications were encountered. Patients have subsequently lived well for 15 and 14 months without jaundice. These results indicate that EMCT for patients with lower bile duct cancer and high operative risk might be an effective alternative for PD.

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Fifteen patients with superficial esophageal cancer were treated by endoscopically. One patient with submucosal cancer was treated by endoscopic microwave coagulation therapy (EMCT) alone. Another 14 cases were performed EMR before EMCT, but removal of cancer lesion totally by EMR was succeeded in only one patient. The residual lesions in the other 13 patients were treated by additional EMCT.
As the results, there was not any recurrence of esophageal cancer in all of the patients during 1 to 48 months of follow-up period.
It was concluded that EMCT was effective for not only early gastric cancer but also superficial esophageal cancer patients.

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The possible use of percutaneous microwave tumor coagulator (PMCT) by using CT for local tumor recurrence of rectal cancer was studied in this paper. Preliminary study was performed using adult Landrace pig and we applied the coagulation time for 3 minutes. The CT guided PMCT was performed for patient with local abdomino-perineal excision. The tumor in the pelvic space were observed on CT images. With patient in the prone position on the CT table, a 14-gauge needle was used to penetrate the tumor under epidural and local anesthesia.
PMCT was performed with an output of 60 watts for 60 seconds at a time. Effects of the PMCT were evaluated by CT images obtained three months after the therapy, there was no evidence of growth for the tumor on the CT images. Clinical symptoms disappered soon after the therapy, and no major complication was observed.
Results of this study suggests that the CT guided PMCT therapy may be useful for local recurrence of rectal cancer.

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A 73-year-old man was admitted to our hospital for the diagnosis of pneumonia and bronchial asthma. He was treated for hepatocellular carcinoma (HCC) with transcatheter arterial embolization (TAE) and percutaneous ethanol injection therapy (PEIT) at other hospital four years ago. By contrast CT scan he was diagnosed as a reccurent HCC in the diameter of 1 cm located on Segment 4. The tumor was not detected by ultrasonography and his respiratory function wasn't good enough for surgical resection. Then we performed CT-guided percutaneous microwave coagulation therapy. Seventh post-therapeutic day contrast CT scan revealed a low density area without enhancement showing the complete necrosis of the tumor. The patient was discharged without any complication on the 14th post-therapeutic day.
CT-guided percutaneous microwave coagulation therapy is useful therapy for HCC which was not detected by ultrasonography.

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We have employed a new technique, percutaneous microwave coagulation therapy (PMCT) with artificial ascites method, for two patients with small hepatocellular carcinoma (HCC), less than 2.5 cm in diameter, located directly under right diaphragma that was considered as dead space on ultrasonography.
The diaphragma near the tumor was not damaged due to the safety space of infused saline solution between liver and diaphragma.
The tumor was completely enclosed within the coagulated area and no recurrence was showed for 5 months after procedure. We did the procedure under local anesthesia and could repeat it again.
PMCT with artificial ascites method was very useful and low invasive therapy for small HCC directly under right diaphragma.

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A 61-year-old man was diagnosed as having hepatocellular carcinoma with liver cirrhosis classified clinical stage II. Because of his poor liver function, he underwent partial resection for lateral segment of the liver and microwave tissue coagulation therapy (MCT) for anterior segment. After 11 month later, he developed intrahepatic recurrence in posterior segment and was treated with percutaneous microwave tissue coagulation therapy (PMCT). He has been well with no recurrence in the liver for over 18 months after the treatment of PMCT.
Because MCT has sufficient effects for local lesions and little side effect, MCT will be useful therapy for hepatocellular carcinoma.

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We treated 2 patients with hepatocellular carcinoma by laparoscopic partial hepatectomy. The longest diameters of the tumors were 25 mm and 30 mm. The both tumors were located at the edge of segment 3 in the liver. After observation of the surface of the liver during laparoscopy as usual, we punctured the surrounding tissues around the tumors with electrode needle and coagulated 80 W for 45 seconds with microwave tissue coagulator. And resected the coagulated lesions with Laparoscopic Coagulating Shears System. The bleeding were few and no serious complications were not found. The resected specimens showed that the tumors were completely resected. Laparoscopic partial hepatectomy was useful for hepatocellular carcinoma located at the edge of the liver.

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Recently, microwave coagulo-necrotic therapy (MCN) is becoming popular as one of the therapy for hepatocellular carcinoma (HCC). But it is not clear whether MCN is an effective treatment for adenocarcinoma as metastatic liver tumor or cholangiocellular carcinoma (CCC). We performed open MCN for a case of CCC with chronic renal failure.
This case was 76 years old male patient. Abdominal CT scan showed a low density mass about 3.5 cm in diameter in the caudate lobe of the liver and compressed inferior vena cava. Considering his poor health status, advanced age and history of chronic renal failure, curative operation with caudate hepatic lobectomy and the resection of inferior vena cava was impossible. So we selected the open MCN bacause of low operative stress and shorter time. Using 30 mm and 10 mm needle, we performed MCN for the tumor all over.
Postoperative course was uneventful and without complications. Through this case, we study and report the effect of MCN for CCC.

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A 59-year-old male who had undergone partial jejunectomy, partial hepatectomy and microwave coagulation therapy (MCT) seven months earlier for jejunal leiomyosarcoma and liver metastasis was admitted with recurrent liver tumors. Abdominal computed tomography revealed five recurrent tumors located in S₂, S₄, S₆ (two lesions ), S₈ of liver, the size of them were less than 2 cm in diameter. PMCT was performed twice for metastatic liver tumors under ultrasound guidance and epidural anesthesia. Pain and fever were not recognized after PMCT. The period of hospitalization was three days. Tumors disappeared in low density area on follow-up CT. After eight months many recurrent lesions were detected in another site of liver. Therefore we performed intra-arterial chemotherapy. This method is thought to be useful for inoperable small multiple metastatic liver tumors, although we have not investigated long-term results of PMCT.

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A 59-year-old man with chronic sinusitis of many years' duration complained of obstruction of the right nostril, particularly on expiration. Rhinoscopic examination revealed a globular tumor, measuring about 1 cm in diameter, behind the right middle meatus. Because the polyp could not be encircled by the loop of a nasal snare, a double-needle electrode (width, 1 mm) was inserted into the polyp three times. Each time a microwave current of 40 watts was applied for 3 seconds to cause coagulation. The polyp became smaller and could be removed with the wire loop (thickness, 0.3 mm) of an aural snare. We consider microwave coagulation therapy useful in the management of selected cases of choanal polyps.

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There have been several reports supporting that nephron-sparing surgery might be accepted in the cases with small renal cell carcinoma recently. From August 1993 to December 1997, in situ non-ischemic enucleation of small renal cell carcinoma using microwave tissue coagulator (Microtaze) was performed in 28 patients (30 renal units) at Nara Medical University and its affiliated hospitals. The post operative courses were uneventful. The mean level of serum creatinine before and one month after operation were 0.94 ± 0.41 mg/dl and 0.97 ± 0.47 mg/dl, and those of creatinine clearance were 82.7 ± 43.5 ml/min and 78.9 ± 37.1 ml/min, respectively. MRI showed about 10 mm-width of ischemic bands around the resected border at one month after operation, however most of them had tendency to reduction gradually. Post operative local tumor recurrence did not occurred during follow up. These results suggested that in situ non-ischemic enucleation of small renal cell carcinoma using microwave tissue coagulator may be simple, secure and suitable for nephron-sparing surgery.

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Advantage of microwavesurgery is high ability of coagulating tissue. The tissue radiated by microwave is only coagulated not carbonized and vaporized. As a result no bleeding happen during and after microwavesurgery.
On the other hand, disadvantage of microwavesurgery is that it is difficult to control area of coagulated tissue and to avoid damage of important tissues and organs in head and neck. And recovery time after microwavesurgery is longer than other methods. It is very important to understand advantage and disadvantage of this method to perform high level operation.
Microwavesurgery is very effective for haemorrhagic tissues and diseases.

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