Tadashi Harada

Microwave surgical treatment of diseases of prostate

A new transurethral probe for microwave radiation of the prostate has been developed. As a preliminary experiment, sliced ham was radiated with microwaves using this probe in order to evaluate the extent of thermal effect. Using mongrel male dogs, microwave coagulation of the prostate was examined. These animal experiments showed marked destruction of the prostate gland. Furthermore, the safety of this method was confirmed on the basis of results from the experiments. Prostatic bladder neck obstruction also has been treated in 6 patients with benign prostatic hypertrophy or carcinoma of the prostate by this technique. There has been no mortality and also no complications. The results of this preliminary clinical trial have been excellent.

Pontine Micturition Center in the Dog

The function and location of the pontine micturition center was studied in ten decerebrate dogs by physiological experiments in which micturition induced by electrical stimulation of the pontine micturition center was compared with reflex micturition in response to bladder filling with physiological saline and by histological studies of the electrolytic lesions made at the stimulated areas. The micturition induced by electrical stimulation of the pontine micturition center showed the same pattern of detrusor contraction, simultaneous urethral relaxation and the elevation of the tail as reflex micturition in response to bladder filling. The peak contraction pressures in both micturitions showed no obvious differences. The electrolytic lesions were histologically identified at the locus coeruleus alpha in six out of 10 dogs, at the locus coeruleus in three and at the peri locus coeruleus alpha in one dog. The coordinated activities of bladder and urethra in the micturition induced by electrical stimulation of locus coeruleus or its subparts suggest that these areas perform an important role in the urine emptying function.

Role of the Pudendal Nerves on the Dynamics of Micturition in the Dog Evaluated by Pressure Flow Emg and Pressure Flow Plot Studies

The role of the pudendal nerves on the dynamics of micturition was studied using 16 decerebrated dogs. The voiding cycles were analyzed by pressure flow EMG and pressure flow plot studies under 3 conditions: control, after unilateral, and after bilateral pudendal nerve transection. In the control condition, highly reproducible reflex micturition with bladder contraction and spasmodic rhythmic sphincter contractions was demonstrated. Two patterns were noted following pudendal nerve transection: reflex micturition and overflow incontinence. Even though reflex micturition could be achieved in 9 out of 16 dogs after bilateral transection, there was decreased bladder emptying as well as absence of spasmodic rhythmic sphincter contractions. Overflow incontinence developed in the remaining 7 dogs (5 dogs after bilateral transection and 2 dogs after unilateral transection). It appears that the pudendal nerves play an important role in emptying the bladder of the dog.

Effect of cerebellectomy on reflex micturition in the decerebrate dog as determined by urodynamic evaluation.

The effect of cerebellectomy on reflex micturition in the decerebrate dog was investigated by cystometric and striated urethral sphincter EMG studies. Before and after cerebellectomy, reflex micturition consisting of bladder contraction and spasmodic contraction of the striated urethral sphincter occurred when a critical degree of filling was reached. Cerebellectomy showed no influence on the striated urethral sphincter EMG activity. However, cerebellectomy produced a significant decrease in threshold volume and threshold pressure during the collecting phase, and also in the contraction pressure and voided volume of the emptying phase. The present study suggests that the cerebellum plays an inhibitory role in the collecting phase and a facilitatory role in the emptying phase during the entire reflex micturition cycle of the decerebrate dog. Further study will have to be done concerning the neurotransmission mechanism that causes these different effects in the collecting and emptying phases.

Role of the Sympathetic Nerve in Bladder and Urethral Sphincter Function During the Micturition Cycle in the Dog Evaluated by Pressure Flow EMG Study

The role of the sympathetic nerve on bladder and urethral sphincter function during the whole micturition cycle, including the collecting and emptying phases, was evaluated on 10 decerebrated dogs by pressure flow EMG study. A series of experiments was performed before and after hypogastric nerve transection. In the control condition and after hypogastric nerve transection, reflex micturition with bladder contraction and spasmodic rhythmic sphincter contractions occurred. Urodynamic parameters of the micturition cycle were statistically compared between control and nerve transection experiments. Threshold volume, threshold pressure and opening pressure showed a small but significant change after nerve transection. A decrease in voided volume seems to be secondarily accompanied with a decrease in threshold volume. It seems that adrenergic nerves play a certain role in bladder function during the collecting phase of the micturition cycle.

ULTRASOUND-GUIDED MICROWAVE THERMOTHERAPY ON A VX-2 CARCINOMA IMPLANTED IN RABBIT KIDNEY

A temperature greater than 60 degrees C was maintained for 60 s within a 5-mm radius of a microwave electrode implanted in a rabbit kidney using 2450 MHz at 100 W for 30 s. Histological examination revealed complete coagulation necrosis in that area. VX-2 cells were inoculated into the kidneys of 10 rabbits. One week later, five rabbits received ultrasound-guided microwave thermotherapy, and the remaining five rabbits received no treatment. All rabbits with microwave thermotherapy had a complete response to treatment while all rabbits without therapy died of cancer within 6 weeks of the VX-2 implantation. These results indicate that ultrasound-guided microwave thermotherapy has the potential of being a nephron-salvaging treatment for small renal tumors.

Microwave Surgical Treatment of the Prostate: Clinical Application of Microwave Surgery as a Tool for Improved Prostatic Electroresection

Microwave surgery as a tool for improved prostatic electroresection is introduced. Prior to electroresection the prostate was coagulated with 2,450 MHz of microwave which was emitted from the bipolar electrode of a specially designed probe. We conducted a comparative study of 35 patients with bladder neck obstruction. There was a microwave coagulation group treated with subsequent transurethral resection (TUR) and a conventional TUR group. Both groups were analyzed for the amount of blood loss, irrigant absorption and the frequency of complications. Both during and following surgery, the former group had a significant reduction in blood loss and had no complications. We conclude that the combination procedure of microwave coagulation and TUR can minimize the disadvantage of formal TUR and may be of value in the treatment of patients with both prostatic obstruction and of hemorrhagic diathesis as well as in high risk patients.

Transcystoscopic Intracavitary Irradiation for Carcinoma of the Bladder: Technique and Preliminary Clinical Results

A remote controlled transcystoscopic intracavitary after-loading unit is introduced for irradiation therapy of bladder carcinoma. With intense radiation therapy a significant dose can be delivered to the tumor during a short interval. We treated 12 patients with transitional cell carcinoma of the bladder using transcystoscopic intracavitary irradiation. Of the patients 9 initially had a complete response, although within several months 3 subsequently had recurrence in a different part of the bladder. Technical difficulties and severe complications were not encountered. The preliminary results and technique of transcystoscopic intracavitary irradiation are reported.

EXPERIMENTAL STUDY OF MICROWAVE COAGULATION OF A VX-2 CARCINOMA IMPLANTED IN RABBIT KIDNEY

This paper describes the results of an experimental study of the microwave coagulation of VX‐2 renal tumors implanted in rabbits. The rabbits undergoing microwave treatment exhibited a satisfactory survival rate and a complete response to treatment, as verified by histological examination. All the rabbits receiving no treatment died within 6 weeks of implantation of the VX‐2 carcinoma. These results indicate that microwave coagulation may be a curative method of treatment for a relatively small renal tumor. Intraoperative real‐time ultrasonic scanning permits the percutaneous microwave coagulation of renal cancer in a clinical situation.

Microwave Coagulation Therapy for Urinary Bladder Tumors

A new device has been developed for microwave coagulation of urinary bladder tumors. Twenty-one patients with urinary bladder tumors were treated by irradiation with microwave energy of 2,450 MHz. Results were obtained as follows: (1) microwave coagulation was performed in 21 patients with transitional cell carcinoma of the urinary bladder. Excluding 4 patients who subsequently received radical cystectomy, 17 patients showed a complete response, although 2 patients subsequently developed recurrences in different parts of the bladder within the following several months. Histological examination of the excised specimen revealed complete eradication of the tumor in 2 patients. In the remaining 2 patients with high-stage tumor (T4), viable tumor cells were noted in the urethra or vaginal wall. (2) Although neither technical difficulties nor severe complications were encountered, transient urinary frequency and calcification of the bladder wall were noted. The results of this study indicate that microwave coagulation may be used in the treatment of both superficial and invasive tumors.