Microwave energy has become a valuable component in the electro-magnetic spectrum. Because of its unique energy source, the microwave radiation can penetrate several centimeters into biologic tissue. The energy is absorbed and converted into heat within the tissue. Clinical applications of microwave irradiation fall into two categories thermotherapy and hyperthermia. Microwave therapy has generated great interest in the field of urology because of its safety, efficiency, and its simplicity as a surgical tool. This review analyses the fundamentals of the science of microwave energy as a therapy and presents an in-depth discussion of its theoretical principles, unique characteristics, appropriateness of application, and its poentiality as a long-term modality for the treatment of urologically-related diseases.
In order to avoid postoperative liver failure after hepatectomy, the evaluation with liver functiontests and the resecting volume should be done actually. By examining our clinical cases retrospectively and prospectively, we got the formula to calculatethe safe resecting volume of the liver tissue especially in the cases of hepatectomy using the Microwave Tissue Coagulator (Microtaze®). With the indicators of the serum disappearance rateof indocyanine green (ICGK), the percent activity of the hepaplastintest (HPT), the volume of the tumor (VT) calculated from the diameter of the main tumor as a sphere, and the long diameter (R) of the oval shaped resecting line which mapped out on the surface of the liver, the formula “460×ICGK+VT (cm3)” was clinically used in the cases of the typical hepatectomy, and the formula “500×ICGK+3.7×HPT+VT-7.5×R-100 (cm3)” was used in the cases of atypical hepatectomyas the safe resecting liver volume. They will be useful in the cases of hepatectomy using the Microwave Tissue Coagulator.
We have applied microwave regional coagulation therapy (MRC) to urinary bladder cancer as anew bladder preserving procedure. This paper describes histological findings of the bladderspecimens which were obtained by transurethral resection or total cystectomy after MRC. Immediately after MRC, heat effect of microwaves was recognized even in the deep muscle layer of the bladder and carcinoma cells were completely necrotized while papillary structure with congested vessels was observed. Histological examination also revealed that granulation formations existed 3 months after MRC and fibrotic changes existed 6 months after MRC in the coagulated regions. However, perforation of the bladder was not evident in all cases. These results indicated that MRC might be a safe and effective procedure for bladder cancer.
For the neurosurgical procedure, a microwave probe with thermo-control system has beendeveloped. This newly-devised microwave probe has the advantage of hemostasis without extremetissue coagulation. This thermo-control system consists of the thermometer, the thermostat andthermo coupple (0.5mm in diameter). The tissue temperature was measured at three points (2mm, 4mm and 6mm) from the tip of the antenna of microwave probe. This probe is effective onmicrowave tissue coagulation and hemostasis of abnormal vesscles of AVM, neoplasms thatare difficult to deal with perform conventional surgical procedure.
Since 1980, the microwave tissue coagulator (microtaze®) has been used for surgery and endoscopictreatment. Recently we devised a new microwave scalpel (blade type electrode) for laparoscopicsurgery which had both coagulative hemostatic and cutting functions. We applied it tolaparoscopic cholecystectomy, and without using electric cautery or laser, obtained a good result. In the surgical procedure, the cystic duct and the cystic artery were divided after clipping, andthen the gall bladder was dissected from the liver bed by retrograde fashion using the microwavescalpel. We treated 19 patients for laparoscopic microwave cholecystectomy and performed the operationsafely. The characteristics of the microwave scalpel are: the hemostatic power is very efficient, the cutting procedure and coagulation can be done simultaneously; and the smoke dose notinterfere during the operation.
Recently, we developed the new tool, which has a blade type scalpel at the tip of the Microtaze, and it can coagulate and cut at the same time. This improved Microtaze was used for theradical operation of the breast cancer, then comparison and examination was performed betweenthe used group and the non-used group of the new Microtaze. The operation was able to finish with only some ligations by using this scalpel, and almostequal between the two groups in amount of bleeding and operation time. No peculiar complicationswere observed in the used group. In future, this operation will be finished with less bleeding and less operation time. The new Microtaze will be used not only breast cancer but also various operations.
In Japan there are more than 15000 patients with cardiac pacemaker in a year. General surgical procedures in pacemaker patients have become common in recent years. General surgeon must have enough knowledge about surgical problem in pacemaker patients. It has been one of the important problem that the use of electrocautery sometimes interferes in the heart rhythm by pacemaker although there is no report, whether microwave scalpel has influence on the pacemaker rhythm or not. Recently we have alternately used electrocautery and new microwave scalpel (Blade type) on same patient during gastrectomy. In this paper, The influence of the electrocautery and microwave scalpel on the pacemaker function is reported respectively. It is demonstrated that a microwave scalpel has not influenced on the pacemaker rhythm as compared with electrocautery.
Recently we performed partial splenectomy and distal pancreatectomy using a new microwavescalpel (blade type electrode). A new microwave scalpel has merit of this high hemostaticperformance and cutting performance. In the 3 cases in which one was iatrogenic intraoperativesplenic injury and two were purpcse of preserving partial splenic function treated by this partialsplenectomy and in the 9 cases or gastric carcinoma teated by this distal pancreatectomy, theseoperations was accomplished safely and postoperative complication was free. These results suggestthat this apparatus, a new microwave scalpel, may well be recommended as a medical electronicsin the splenic and pancreatic surgery.