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R Muschter

Publications and source records attributed to R Muschter.

At least 19 recordsLinked to original sources
PubMed2000

[Treatment of benign prostatic hyperplasia syndrome. 2: Interventional therapy].

The invasive treatment modalities available für BPH can be divided into interstitial therapy without removal of tissue (e.g. stents), and those involving delayed tissue ablation (thermal/coagulation procedures, e.g. laser ablation, microwave thermo-ablation, high-intensity ultrasound). The latter procedures (coagulation) more often permit a nonbloody intervention, the sphincter usually remains uninjured, and retrograde ejaculation is less frequent. A third group of options is interventional treatment, with immediate ablation of tissue (vaporization, resection), which is more invasive and associated with a higher risk of complications than the two first-mentioned groups. An advantage of these options is the avoidance of a longer-term catheterization with its associated risks. Help is provided for deciding which procedure should be used in which patient.

Equipment Design↗
PubMed1999

[Interventional therapy of BPH syndrome].

The invasive treatment modalities available for BPH can be divided into interstitial therapy without removal of tissue (e.g. stents), and those involving delayed tissue ablation (thermal/coagulation procedures, e.g. laser ablation, microwave thermo-ablation, high-intensity ultrasound). The latter procedures (coagulation) more often permit a non-bloody intervention, the sphincter usually remains uninjured, and retrograde ejaculation is less frequent. A third group of options is interventional treatment with immediate ablation of tissue (vaporization, resection), which is more invasive and associated with a higher risk of complications than the two first-mentioned groups. An advantage of these options is the avoidance of a longer-term catheterization with its associated risks. Help is provided for deciding which procedure should be used in which patient.

Humans↗
PubMed1999

Coagulative interstitial laser-induced thermotherapy of benign prostatic hyperplasia: online imaging with a T2-weighted fast spin-echo MR sequence--experience in six patients.

PURPOSE: To determine if hypointense lesions clearly outline on T2-weighted fast spin-echo (SE) magnetic resonance (MR) images obtained during coagulative interstitial laser-induced thermotherapy (LITT) of a prostate with benign hyperplasia. MATERIALS AND METHODS: In six patients with benign prostatic hyperplasia (BPH), 12 LITT treatments were followed online with repetitive axial T2-weighted fast SE imaging (repetition time, 3,700 msec; echo time, 138 msec; acquisition time, 19 seconds). Development, time course, correlation with interstitial tissue temperature, and diameters of hypointense lesions around the laser diffusor tip were investigated. Lesion diameters on T2-weighted images acquired during LITT were compared with diameters of final lesions on T2-weighted images and unperfused lesions on enhanced T1-weighted SE images obtained at the end of therapy. RESULTS: Hypointense lesions developed within 20-40 seconds of LITT. Average correlation coefficients between interstitial temperature development and signal intensity development were 0.92 during LITT and 0.90 after LITT. Regression slopes were significantly steeper during LITT (0.67% signal intensity change per degree Celsius) than after LITT (0.47% per degree Celsius; P = .038). Lesions remained visible after LITT for all procedures. Average maximum diameters of lesions were 1-3 mm larger during LITT than after LITT (P = .0006-.019). CONCLUSION: Repetitive T2-weighted fast SE MR imaging during interstitial coagulative LITT of BPH demonstrates the development of permanent hypointense prostate lesions. However, posttherapeutic lesion diameters tend to be overestimated during LITT.

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PubMed1999

Interstitial laser therapy of benign prostatic hyperplasia.

The objective of interstitial laser coagulation (ILC) of benign prostatic enlargement is to achieve a marked volume reduction and to decrease bladder outlet obstruction and lower urinary tract symptoms with minimal morbidity. Coagulation necrosis is generated well inside the adenoma by means of specifically designed laser applicators combined with either a Nd:YAG laser or a diode laser. Because the laser applicators can be inserted as deeply and as often as necessary, it is possible to coagulate any amount of tissue at any desired location while preserving adjacent structures such as the urethra. Postprocedural, the intraprostatic lesions result in secondary atrophy and regression of the prostate lobes, rather than sloughing of necrotic tissue. Several single-armed and randomized studies indicated the effectiveness of interstitial laser coagulation of BPH-syndrome. Marked improvements in AUA score, peak flow rate, residual urine volume and prostate volume were reported. Pressure-flow studies demonstrated a sufficient decrease of the intravesical/detrusor pressure, urethral opening pressure and urethral resistance. Long-term results demonstrating sustained success for up to 3 years were reported on a series of 394 patients. ILC is suitable to debulk even large prostates and to treat highly obstructive patients. Therefore, ILC can be seen as a true alternative to TURP with certain advantages, such as almost no serious morbidity and with certain disadvantages, such as the need for postoperative catheterization. However, ILC can be done under local anesthesia and does not require hospitalization.

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PubMed1998

Interstitial laser prostatectomy.

In an attempt to minimize the need for hospitalization and the associated perioperative and postoperative morbidity, alternatives to transurethral resection of the prostate (the standard treatment modality for benign prostatic hyperplasia) have been sought. Various types of laser prostatectomy have been proposed. Interstitial laser coagulation is performed by placing laser-diffusing fibers directly in the hyperplastic prostatic adenoma. The goal is to achieve coagulation necrosis within the adenoma, which causes the prostatic lobes to regress and thereby relieves the bladder outlet obstruction. Either the transurethral cystoscopic approach or the perineal approach can be used for laser application. Numerous published studies have shown that this laser procedure safely and effectively decreases symptoms of prostatism, increases the urinary flow rate, and reduces the volume of the prostate. Because of substantial tissue edema after treatment, catheter drainage may be necessary for 7 to 21 days. Although retrograde ejaculation has occurred occasionally (affecting from 0 to 11.9% of patients in reported studies) and uncomplicated urinary tract infections are common after interstitial laser coagulation, no cases of impotence or sustained incontinence have been described. Because interstitial laser coagulation is not associated with blood loss or intravascular fluid shifts and, if necessary, can be performed with a combination of local anesthesia and intravenous sedation, even high-risk patients are candidates for this procedure.

Humans↗
PubMed1997

Interstitial laser coagulation in the treatment of benign prostatic hyperplasia using a diode-laser system with temperature feedback.

OBJECTIVE: To report the initial results of the treatment of patients with benign prostatic hyperplasia using interstitial laser coagulation (ILC) performed with a temperature-sensing laser system. PATIENTS AND METHODS: Twenty-five patients were treated using ILC and in 12, 78 temperature-power curves were recorded. The aim of the treatment was to maintain a temperature of 100 degrees C during the entire treatment cycle, using the temperature-triggered feed-back system. The time to reach the maximum temperature, the maximum temperature and the energy delivered were related to the location of the punctures within the prostate. The clinical outcome at 1 and 3 months was evaluated with symptom scores and uroflowmetry variables. RESULTS: Heating at the apex seemed to require less energy to achieve and maintain higher temperatures than heating of the median lobe or base of the prostate. Patients improved markedly 1 and 3 months after treatment; the respective mean symptom scores improved from 20.6 before treatment to 9.4 and 6.9, the maximum urinary flow rates from 9.1 mL/s to 14.1 mL/s and 20.3 mL/s and the post-void residual volume decreased significantly from 71 mL to 31 mL and 11 mL. No significant complications (incontinence, impotence or haemorrhage requiring transfusion) occurred. CONCLUSION: The energy needed to achieve coagulation differed at sites within the prostate, depending on local circumstances. Good results were obtained using the tissue-adaptive laser system.

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PubMed1997

[Laser thermocoagulation of adenoma of the prostate using an interstitial approach].

Interstitial laser coagulation (ILC) is a minimally invasive treatment for benign prostatic hyperplasia (BPH). The objective of ILC is to induce shrinking of the prostate while preserving all surrounding tissues. To achieve thermal coagulation well inside the adenoma, not at its urethral surface, laser radiation of a Nd:YAG laser or a diode laser is transmitted by specially designed laser fibers repeatedly placed in the prostate tissue. This results in secondary atrophy and regression of the prostate lobes, not sloughing of necrotic tissue. Since, July 1991, more than 800 patients have been treated in several studies. Based on initial experiences, many technical and procedural improvements of ILC have been introduced for clinical use, such as advanced radiation programs and new application devices including optical feedback systems. Imaging studies demonstrated treatment effects and allowed further treatment optimization. Clinical studies have demonstrated the safety and efficacy of ILC. This review summarizes several articles published on ILC and reports initial results of ongoing studies comparing ILC and transurethral resection of the prostate (TURP).

Aluminum Silicates↗
PubMed1996

Alteration of laser-tissue interaction with the 805 nm diode laser using indocyanine green in the canine prostate.

BACKGROUND AND OBJECTIVE: Research interests in laser prostatectomy continue to evaluate a variety of wavelengths and treatment parameters in an effort to optimize treatment. Recently, a semiconductor diode laser with a wavelength of 805 nm has become available for clinical use; however, free-beam noncontact applications were limited by the low power output (25 W). In this study in the canine prostate, the possible potentiating effects of intravenously administered indocyanine green (ICG) were evaluated with the 805 nm diode laser. STUDY DESIGN/MATERIALS AND METHODS: A total of 16 fixed position, free-beam lasings were performed at 25 W for 60 sec in four dogs with eight lasings before and eight lasings after ICG administration. Endoscopic observations and measurements of lesion volumes were used to evaluate the laser-tissue interactions. RESULTS: Prior to ICG administration, we observed that side fire irradiation produced primarily small coagulative lesions. Following ICG administration, however, immediate and more noticeable tissue vaporization occurred, although total lesion size was not increased. Pathologic review demonstrated less coagulation and hyperemia, but a larger vaporized cavity in the ICG treated tissue. CONCLUSION: These findings suggest intravenous ICG alters laser-tissue interaction with the 805 nm diode laser in the canine prostate. The use of the 805 nm diode laser with enhancing chromophores deserves further investigation.

Animals↗
PubMed1996

[MRI monitoring before, during and after interstitial laser-induced hyperthermia of benign prostatic hyperplasia. Initial clinical experiences].

PURPOSE: To assess the clinical value of MRI in patients with benign prostatic hyperplasia (BPH) before, during, and after interstitial laser-induced thermotherapy (LITT) of the prostate. METHODS: Ten patients with symptomatic BPH had MRI examinations of the prostate 48 h before and after LITT. Online monitoring with MRI at 1.5 T of interstitial Nd:YAG laser energy deposition in the prostate was performed in two patients, repeating a T1-weighted FLASH sequence (TR 100 ms, TE 5 ms, flip angle 90 degrees) every 20 s. Follow-up MRI examinations 2-3 weeks, 6-8 weeks, and 6-12 months after LITT were carried out in eight patients, using T2-weighted FSE images and contrast-enhanced T1-weighted SE images. RESULTS: The prostate was well delineated in all patients on T2-weighted FSE images, with a rather homogeneous peripheral gland and an inhomogeneous central gland. Volume measurements yielded reproducibilities of 3.2%-4.7%. Signal intensity in the FLASH sequence decreased during LITT, both in the prostate in vivo and in specimens of bovine prostate and seminal vesicles in vitro, with signal developments running in parallel. Areas of energy deposition and signal alteration were not sharply delineated. The latter margin of the laser-induced lesions could not be predicted from the FLASH images, while the tip of the laser fibre was easily recognized. Contrast-enhanced T1-weighted MR images immediately after LITT clearly demarcated low signal intensity laser lesions from high signal intensity surrounding prostate tissue. Follow-up examinations showed a decrease of 20% of prostate volume over a period of 6-12 months after LITT. Correlation between prostate volume development and lesion volume alteration was 0.85-0.90 (P = 0.002-0.007) at all follow-up times. CONCLUSIONS: MRI allows rather precise recognition of intraprostatic alterations after LITT, including volume changes over a period of up to 1 year after therapy that can be predicted immediately after LITT. While laser energy deposition in the prostate can be monitored by MRI with T1-weighted FLASH sequences as a function of temperature alteration, it is not possible to determine the lesion margins immediately from the FLASH images. Online temperature development map generation will be necessary to influence on-going LITT procedures with MRI.

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PubMed1996

Initial human clinical experience with diode laser interstitial treatment of benign prostatic hyperplasia.

OBJECTIVES: To report the initial results of treatment of outlet obstruction induced by benign prostatic hyperplasia (BPH) using interstitial laser coagulation performed with the Indigo 830 nm diode laser system. METHODS: A group of 112 men with lower urinary tract symptoms caused by BPH underwent treatment with the Indigo 830 nm laser system between October 1994 and November 1995. Patients were assessed prior to treatment and at specified post-treatment intervals for symptom score, uroflow, postvoid residual, and prostate volume. Adverse events and changes in laboratory parameters were monitored at each post-treatment visit to investigate safety of the procedure. RESULTS: Symptom score decreased from 20.9 at initial measurement to 9.6 at 3 months after procedure and 7.9 at 6 months. Uroflow rate increased from 8.0 mL/s initially to 15.2 and 14.2 mL/s at 3 and 6 months, respectively. Residual bladder volumes decreased from 105 mL initially to 59 and 38 mL at 3 and 6 months, respectively. There were no major complications (impotence, sustained incontinence, significant blood loss). Minor complications occurred in a small number of patients but were generally associated with urinary tract infection in patients with catheters. Three patients (2.7%) required retreatment and underwent transurethral resection of the prostate. CONCLUSIONS: Interstitial laser coagulation using an 830-nm diode laser system appears to be a promising new treatment, with substantial improvements in objective and subjective parameters of obstruction and a favorable side-effect profile.

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PubMed1995

The effect of popcorn and carbonization on neodymium: YAG laser dosimetry in the canine model.

Neodymium:YAG laser irradiation of the canine prostate provides an experimental model for the study of the laser-tissue interaction in laser prostatectomy. Prostate irradiation was undertaken using right-angle-firing laser fibers through an open suprapubic cystotomy, and the procedure was monitored by video endoscopy via a perineal urethrostomy. The effects of popcorn and surface carbonization on intraprostatic heating profiles were determined by interstitial thermometry. We found that popcorn reduced intraprostatic temperatures but that continued irradiation resulted in the restoration of heating. Carbonization resulted in the loss of heating ability deep in the prostate. These observations allow the urologist to understand the thermal implications of observed surface change and to modify lasing parameters during surgery to obtain the desired laser-tissue interaction.

Animals↗
PubMed1995

Technique and results of interstitial laser coagulation.

By use of thermal "ablation" techniques to apply heat to the prostate from the urethra, the coagulation volume is limited by the limited penetration depth of suitable radiation sources, e.g., lasers, and by heat conduction. Secondarily, the coagulated tissue is removed by sloughing. Interstitial heat application was expected to overcome these problems. Our initial in vitro and animal studies using different light guides for interstitial Nd:YAG laser radiation showed that small, carbonized lesions were created by bare fibers, whereas large, homogeneous coagulation zones measuring up to 2 cm in diameter were produced by specially designed ITT (interstitial thermotherapy) fibers, which secondarily resulted in marked volume reduction by atrophy. Further experiments using such applicators resulted in an operation technique suitable for clinical routine in the treatment of symptomatic benign prostatic hyperplasia (BPH). These laser applicators are inserted into the prostate either transurethrally through a cystoscope under direct vision or percutaneously from the perineum under transrectal ultrasound guidance. The number of placements depends on the size and configuration of the gland. Radiation parameters were optimized for each system. To avoid charring, relatively low levels of laser power and long radiation periods (e.g., 7 W for 10 min) or power-formatting programs (e.g., stepwise reduction of power from 20 to 7 W for a total radiation time of 3 min) are applied. Beginning in July 1991, more than 350 unselected patients with BPH were treated with interstitial laser coagulation in our department, of whom 239 were followed for at least 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1995

Electrosurgical vaporization of the prostate in the canine model.

OBJECTIVES: To investigate the histopathologic changes and heating patterns caused by electrosurgical vaporization of the prostate in the living canine model. METHODS: Prostate electrosurgical vaporization was undertaken in the canine model. Temperatures within and near the prostate and of the irrigation fluid were measured during a single pass and during the creation of a vaporized cavity. The prostate and adjacent tissues were examined by gross and microscopic pathology. RESULTS: Coagulation occurred deep to the vaporization zone for 1.38 to 1.44 mm for a single pass of the rolling cylinder and up to 2.52 mm for multiple passes. Thermometry revealed temperature increases of only 4 degrees C 5 mm away from the vaporization site. The largest temperature increases were found in the irrigation fluid as it passed through the prostatic fossa. Microscopic pathology revealed no damage to adjacent tissues. CONCLUSIONS: Electrosurgical vaporization creates minimal deep heating and coagulation beyond the vaporized cavity. The majority of the heat is removed by the irrigation fluid.

Animals↗
PubMed1995

Interstitial laser therapy outcomes in benign prostatic hyperplasia.

Two hundred thirty-nine patients with benign prostatic hyperplasia (BPH) were treated using interstitial laser coagulation (ILC or LITT; laser-induced interstitial thermotherapy), and the long-term results were determined. In this minimally invasive procedure, special laser light guides were inserted into the adenoma tissue in order to achieve primary large-volume coagulation necrosis and secondary shrinking, leaving the urethra intact. The AUA Symptom Scores improved markedly, from an average of 25 pretreatment to an average of 6 at 1 year. Peak urine flow rates improved commensurably, from 8 mL/sec pretreatment to 18 mL/sec at 1 year. Postoperative irritative symptoms occurred occasionally, affecting only 12% of patients. Significant complications were rare, with 4% of patients suffering strictures and 7% retrograde ejaculation. No patients suffered impotence or incontinence. Only 9.6% of patients required retreatment for BPH during 12 months of follow-up. Twelve patients were treated with subsequent transurethral laser incision of the bladder neck in order to shorten the time required for improvement of voiding function.

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PubMed1995

[Interstitial laser-induced coagulation of the prostate for therapy of benign hyperplasia].

Interstitial laser-induced coagulation (ILC) is a new, minimally invasive, procedure for the treatment of benign prostatic hyperplasia (BPH). It is based on the placement of special light guides in the prostatic tissue, either transurethrally or perineally. The radiation source is a Nd-YAG laser, which is active for 3 or 5 min per fiber placement, respectively, with the power reduced stepwise. The coagulation necroses caused shrink during follow-up, leading to a decrease in the obstruction. In 239 patients treated in this way the mean I-PSS-Score fell from 25.4 to 8.1 points and the quality of life index from 4.1 to 1.6, the urinary peak flow rate increased from 7.7 to 16.3 ml/s, the residual urine volume fell from 151 to 32 ml, and the mean prostate volume declined from 47.4 to 32.2 ml in the first 3 months of follow up; 9.2% of the patients required further treatment within 1 year because of persistent obstruction. The complication rate was low. Statistical analysis showed no factors allowing prediction of the outcome. ILC is an effective method with few side effects and complications, and it has a wide range of indications for all BPH patients.

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PubMed1994

The optimization of laser prostatectomy. Part I: Free beam side fire coagulation.

OBJECTIVES: To study laser-tissue interaction and develop unifying principles for the optimization of free beam side fire neodymium:yttrium-aluminum-garnet (Nd:YAG) laser coagulation prostatectomy. METHODS: The heating patterns and coagulation volumes created by different right angle deflecting fibers were studied at different wattages and times in potato and canine models. RESULTS: In the potato, higher wattage resulted in deeper and more rapid heating. The high power density fibers created lesions of smaller volume which increased less with rising wattage than those fibers of lower power density. In the canine model, carbonization decreased heat penetration, and "popcorn" decreased superficial temperature without altering lesion size as long as it occurred without carbonization. As lasing progressed, smaller incremental increases in coagulation depth were achieved. CONCLUSIONS: To optimize coagulation laser prostatectomy, the surgeon should operate at the highest wattage which does not cause carbonization. The visualized intraoperative laser-tissue interaction allows the adjustment of laser power during the case as needed.

Animals↗
PubMed1994

The optimization of laser prostatectomy. Part II: Other lasing techniques.

OBJECTIVES: To evaluate the laser-tissue interaction during neodymium:yttrium-aluminum-garnet (Nd:YAG) irradiation using right angle firing fibers in motion, contact vaporization applicators, and interstitial lightguides. METHODS: The heating patterns and coagulation volumes created during right angle firing fiber pulling and painting, contact tip vaporization, and interstitial thermotherapy were studied in potato and canine models. RESULTS: High power density right angle firing fibers can be used in motion to create coagulation lesions at 40 and 60 watts (W). The depth of such lesions was less than that obtained during fixed free beam side fire coagulation. Contact vaporization applicators caused tissue vaporization without creating concurrent coagulation lesions. Interstitial lightguide thermotherapy created coagulation lesions without carbonization using A step power reduction approach during irradiation. CONCLUSIONS: Each of the investigated methods had the ability to destroy prostate tissue, and therefore may have a role in the evolution of laser prostatectomy.

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