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T A Boon

Publications and source records attributed to T A Boon.

14 recordsLinked to original sources
PubMed1995

Side-firing devices for laser prostatectomy. An overview.

Transurethral laser coagulation of the prostate has become an accepted treatment for benign prostatic hyperplasia (BPH). The most common method is the use of a sideward-firing fiber that, once inserted in the prostatic area, irradiates the abundant prostatic tissue with Nd:YAG laser light. In this study, eight different side-firing fibers that are commercially available were evaluated. The devices can be characterized by the way laser light is deflected sideward and by their thermal behavior. Most of the eight devices differ with regard to the angle at which the laser beam is deflected, the spot size on the irradiated tissue surface, and the heating of the device itself. Implementation of the optical and thermal characteristics of each device in the treatment protocol will contribute to the optimal use of laser energy for prostatectomy.

Equipment Design↗
PubMed1995

Laser prostatectomy for patients with benign prostatic hyperplasia: a prospective randomized study comparing two different techniques using the Prolase-II fiber.

Laser prostatectomy for patients with complaints due to benign prostatic hyperplasia is a relatively new treatment option. The most effective procedure for coagulation and vaporization of the prostate is not yet known. In a prospective randomized study of 30 patients, 2 techniques for the delivery of laser energy were compared at 40 W for 90 s. The complications were minimal and antegrade ejaculation was preserved in 15 of 18 potent men. In 24 patients urodynamics evaluation was possible. In both groups a significant reduction in the symptom score was observed. The decrease in detrusor pressure at maximal flow and the increase in flow rate were, however, disappointing. No significant difference in the results was found between the two groups. The power setting needs to be changed in further studies.

Aged↗
PubMed1995

International prostate symptom score and quality of life assessment versus urodynamic parameters in men with benign prostatic hyperplasia symptoms.

In 207 men with symptomatic benign prostatic hyperplasia the international prostate symptom score and score on quality of life were collected. Cystometric tests with pressure-flow studies were performed in these patients with special attention to the assessment of obstruction grade. Of the men 24% appeared not to have obstruction. A significant correlation was found between size of the prostate and grade of obstruction. No correlation was found between obstruction grade, and any symptom score or quality of life score, while symptom score and quality of life correlated well. In 41 patients the outcome of laser prostatectomy was evaluated 6 months after the procedure. Mean symptom score decreased from 19.1 to 5.4 and mean quality of life score decreased from 3.7 to 1.3 in the 31 obstruction patients, compared to decreases of 19.6 to 10.1 and 3.6 to 2.6, respectively, in 10 without obstruction. The improvement in the obstruction patients was significantly better but nonobstruction patients will benefit from prostatectomy as well.

Aged↗
PubMed1994

[Laser prostatectomy as alternative to transurethral prostate resection in benign prostatic hyperplasia].

OBJECTIVE: Assessment of the results of laser prostatectomy, as a treatment for benign prostatic hyperplasia (BPH). DESIGN: Prospective case control study. SETTING: University Hospital Utrecht, the Netherlands. METHOD: Between February 1992 and May 1993, 54 men with their micturition complaints due to BPH were treated with laser prostatectomy (TULIP system). Results were assessed using the international prostatic symptom score (IPSS), the maximal flow and urodynamic tests. The results were compared retrospectively with results of transurethral resection of the prostate (TURP; n = 40): both groups were urodynamically identical. RESULTS: Of the 54 patients, 10 could not be evaluated 6 months after treatment (5 of them underwent TURP or a second laser prostatectomy). In 40 patients complete evaluation including urodynamics before and six months after treatment was possible. A significant decrease in the symptom score from 19.3 (SD: 7.6) to 6.3 (SD: 5.4) and increase of the maximal flow during pressure-flow studies from 9.6 to 15.8 ml per second were observed. The decrease of the voiding pressure at 6 months after TURP in comparison with laser prostatectomy was close to significance (p = 0.05); the other improvements after urodynamics were comparable. CONCLUSION: Laser prostatectomy is a promising new therapy for BPH.

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PubMed1994

Optimization of laser prostatectomy.

A recent development in the treatment of Benign Prostatic Hyperplasia (BPH) is the use of a side firing fiber device coupled with a Nd:YAG laser. In this study, a numerical and an in-vitro model were developed to calculate and visualize the temperature distribution and the associated tissue necrosis due to irradiation of the prostate with Nd:YAG laser light. Different irradiation modalities were included: a static beam, with the irradiating fiber remaining at one place and a moving beam, with the fiber scanning over the surface at different speeds. Also blood vessels were incorporated in the model and showed to have major influence on the resulting tissue necrosis.

Computer Simulation↗
PubMed1992

Squamous cell carcinoma of the penis. II. Treatment of the primary tumor.

The treatment of the primary tumor in 110 patients with squamous cell carcinoma of the penis seen between 1956 and 1989 was reviewed. Small tumors had generally been treated by penis conserving methods, such as circumcision, local excision and external radiotherapy alone or after circumcision or local excision. Since 1982 we have used the neodymium:YAG laser as a penis conserving method. In 51 patients (46%) penis conserving treatment had been performed and 59 (54%) had undergone some form of amputation. Overall, 16 of 110 patients (15%) had local recurrence. The risk of local recurrence after penis conserving therapy was significantly related to T category, with 10% local recurrences in stage T1 tumors in contrast to 32% and 100% in stages T2 and T3 tumors, respectively. All of the recurrences in patients with stage T1 tumors were strictly local and all were salvaged. In our view penis conserving therapy is a safe procedure in patients with stage T1 tumors and should always be attempted first. Amputation is considered to be overtreatment in these cases. Of 6 recurrences in the conservatively treated stage T2 disease group 4 were strictly local. These were all well or moderately differentiated tumors, not exceeding 3.5 cm. in diameter. We suggest penile conservation for this subgroup of T2 tumors. However, partial amputation is recommended for poorly differentiated stage T2 tumors. Local failure was observed in all stage T3 tumors treated with external radiation. In general, penis conservation in stage T3 tumors should not be attempted with the treatment modalities available to date. Comparing the different methods of penis conservation, used in 49 stages T1 and T2 tumors, no difference in local recurrence rate (18%) was observed among surgery, laser and external beam radiation. In view of the low morbidity, cutting and coagulation properties and minimal tissue changes, use of the neodymium:YAG laser would be our first choice of treatment modality. Penile conservation should be attempted only when frequent and long lasting followup is guaranteed, since local recurrences can appear as late as 8 years after primary treatment.

Adult↗
PubMed1988

Sapphire probe laser surgery for localized carcinoma of the penis.

Cancer of the penis is an uncommon disease in the western world, but it causes significant morbidity and mortality worldwide. Discussions have tended to centre around issues of local tumor control and the functional status of the penis after treatment. Since November 1982 we have treated localized squamous cell penile cancer (Tis, T1 and T2, Classification UICC, Geneva 1978) with the Nd-YAG laser. Sixteen patients (3Tis, 5T1 and 8T2 tumors) are included in this study with a follow-up of 4 to 36 months (mean 17 months). Eight out of 16 patients were treated with the sapphire probe exclusively, the other eight patients by scalpel excision followed by laser irradiation. No recurrent tumor was observed in 13 patients, one patient developed a recurrence at a non-treated part of the glans penis after 14 months, one patient showed Tis after 5 months near the treated side and in one patient an incomplete laser resection was followed by partial penectomy after 1 month. Sapphire probe laser excision is a safe procedure leading to a good cosmetic aspect with maintenance of the functional integrity of the penis.

Adult↗
PubMed1987

Preliminary results with iodine-125 seeds for permanent implantation in patients with localized prostatic cancer.

Since August 1981, a permanent implantation with iodine-125 seeds has been performed in 41 patients with localized prostatic cancer. The seeds are implanted through a suprapubic incision. This gives the opportunity also to perform a diagnostic dissection of the regional lymph nodes. In five patients, the nodes were positive. In 4 out of these 5 patients bone metastases became manifest within one year. Two patients died of disseminated tumor, the first also had a local recurrence. Two other patients died shortly after treatment because of heart failure, while a third patient also died of heart failure, 2 years after implantation. Out of 31 patients with a follow-up period of 6 months or longer, distant metastases were found in four, in 2 followed by a local recurrence in the prostate. We can conclude that the preliminary results of this technique are encouraging with only three local recurrences in 41 patients. The prognostic value of positive lymph nodes was once again established.

Brachytherapy↗
PubMed1982

Estrogen-induced deficiency and decrease in antithrombin III activity in patients with prostatic cancer.

Plasma antithrombin III activity was studied in 22 patients with prostatic cancer who were on estrogen therapy. Normal plasma antithrombin III activity varies between 0.80 and 1.40 U. per ml. A loading dose of 15 mg. diethylstilbestrol daily resulted in a marked decrease in plasma antithrombin III activity (mean 0.24 U. per ml.). Patients with the lower end of normal range of pre-treatment plasma antithrombin III activity may suffer acquired antithrombin III deficiency and, thus, a concomitantly increased risk of thromboembolic complications as a result of estrogen treatment. Patients on maintenance therapy of approximately 1 mg. daily appear to have normal plasma antithrombin III levels. The results obtained suggest that plasma antithrombin III activity should be monitored before and during estrogen therapy in patients with prostatic cancer.

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