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Transurethral convective water vapor as a treatment for lower urinary tract symptomatology due to benign prostatic hyperplasia using the Rezūm(®) system: evaluation of acute ablative capabilities in the human prostate.

Dixon CM, Rijo Cedano E, Mynderse LA, Larson TR - Res Rep Urol (2015)

Bottom Line: The largest lesion volume was 35.1 cm(3).The resulting coalescing ablative lesions, as seen on MRI, were confined to the transition zone.These studies confirm the ablative capabilities of vapor, validate the thermodynamic principles of convective heating, and allow for further clinical studies.

View Article: PubMed Central - PubMed

Affiliation: Lenox Hill Hospital, New York, NY, USA.

ABSTRACT

Background: The purpose of this study was to assess the acute ablative characteristics of transurethral convective water vapor (steam) using the Rezūm(®) system in men with benign prostatic hyperplasia through histologic and radiographic studies.

Methods: Seven patients were treated with transurethral intraprostatic injections of sterile steam under endoscopic visualization followed by previously scheduled adenectomies. The extirpated adenomas were grossly examined followed by whole mount sectioning and staining with triphenyl-tetrazolium chloride (TTC) to evaluate thermal ablation. Histology was performed after hematoxylin and eosin staining on one prostate. After review of results from the first patient cohort, an additional 15 patients with clinical benign prostatic hyperplasia were treated followed by gadolinium-enhanced magnetic resonance imaging (MRI) at one week.

Results: In the first patient cohort, gross examination of TTC-stained tissue showed thermal ablation in the transition zone. In addition, there was a distinct interface between viable and necrotic prostatic parenchyma. Histopathologic examination revealed TTC staining-outlined necrotic versus viable tissue. Gadolinium-enhanced MRIs in the cohort of 15 patients demonstrated lesion defects in all patients at 1 week post-procedure. Coalesced lesions were noted with a mean (± standard deviation) lesion volume of 9.6±8.5 cm(3). The largest lesion volume was 35.1 cm(3). Ablation using vapor was rapid and remained confined to the transition zone, consistent with the thermodynamic principles of convective thermal energy transfer.

Conclusion: Thermal ablation was observed in all specimens. The resulting coalescing ablative lesions, as seen on MRI, were confined to the transition zone. These studies confirm the ablative capabilities of vapor, validate the thermodynamic principles of convective heating, and allow for further clinical studies.

No MeSH data available.


Related in: MedlinePlus

Gadolinium-enhanced transverse (A) and coronal (B) magnetic resonance images showing large thermal lesions outlining the transition zone while preserving the peripheral zone and urethra.
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f5-rru-7-013: Gadolinium-enhanced transverse (A) and coronal (B) magnetic resonance images showing large thermal lesions outlining the transition zone while preserving the peripheral zone and urethra.

Mentions: In the Rezūm system-treated group without adenectomy, the mean number of steam injections per lateral lobe was 2.3 (range 1–4) and the mean number of injections per median lobe in four patients was 2.5 (range 2–3; Table 3). The MRIs of these 15 treated patients demonstrated prostatic gadolinium defects in all patients at 1 week from therapy. This merging of treatment zones appeared to mimic that which was observed using TTC staining on adenectomy whole mount specimens. Coalesced lesions were noted in each lateral lobe corresponding to the targeted treatment sites. At 1 week, the mean (± standard deviation) gadolinium defect volume was 9.6±8.5 cm3 (Table 4). The largest defect volume was 35.1 cm3 (Figure 4A and B). Gadolinium defects have been shown to correlate with histological proven necrosis in previous studies.5 Defects were observed in the transition zone. No thermal effects were seen in the peripheral zone. In several cases, the gadolinium defect outlined the boundary of the transition zone without passing through to the peripheral zone (Figure 5A and B).


Transurethral convective water vapor as a treatment for lower urinary tract symptomatology due to benign prostatic hyperplasia using the Rezūm(®) system: evaluation of acute ablative capabilities in the human prostate.

Dixon CM, Rijo Cedano E, Mynderse LA, Larson TR - Res Rep Urol (2015)

Gadolinium-enhanced transverse (A) and coronal (B) magnetic resonance images showing large thermal lesions outlining the transition zone while preserving the peripheral zone and urethra.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321608&req=5

f5-rru-7-013: Gadolinium-enhanced transverse (A) and coronal (B) magnetic resonance images showing large thermal lesions outlining the transition zone while preserving the peripheral zone and urethra.
Mentions: In the Rezūm system-treated group without adenectomy, the mean number of steam injections per lateral lobe was 2.3 (range 1–4) and the mean number of injections per median lobe in four patients was 2.5 (range 2–3; Table 3). The MRIs of these 15 treated patients demonstrated prostatic gadolinium defects in all patients at 1 week from therapy. This merging of treatment zones appeared to mimic that which was observed using TTC staining on adenectomy whole mount specimens. Coalesced lesions were noted in each lateral lobe corresponding to the targeted treatment sites. At 1 week, the mean (± standard deviation) gadolinium defect volume was 9.6±8.5 cm3 (Table 4). The largest defect volume was 35.1 cm3 (Figure 4A and B). Gadolinium defects have been shown to correlate with histological proven necrosis in previous studies.5 Defects were observed in the transition zone. No thermal effects were seen in the peripheral zone. In several cases, the gadolinium defect outlined the boundary of the transition zone without passing through to the peripheral zone (Figure 5A and B).

Bottom Line: The largest lesion volume was 35.1 cm(3).The resulting coalescing ablative lesions, as seen on MRI, were confined to the transition zone.These studies confirm the ablative capabilities of vapor, validate the thermodynamic principles of convective heating, and allow for further clinical studies.

View Article: PubMed Central - PubMed

Affiliation: Lenox Hill Hospital, New York, NY, USA.

ABSTRACT

Background: The purpose of this study was to assess the acute ablative characteristics of transurethral convective water vapor (steam) using the Rezūm(®) system in men with benign prostatic hyperplasia through histologic and radiographic studies.

Methods: Seven patients were treated with transurethral intraprostatic injections of sterile steam under endoscopic visualization followed by previously scheduled adenectomies. The extirpated adenomas were grossly examined followed by whole mount sectioning and staining with triphenyl-tetrazolium chloride (TTC) to evaluate thermal ablation. Histology was performed after hematoxylin and eosin staining on one prostate. After review of results from the first patient cohort, an additional 15 patients with clinical benign prostatic hyperplasia were treated followed by gadolinium-enhanced magnetic resonance imaging (MRI) at one week.

Results: In the first patient cohort, gross examination of TTC-stained tissue showed thermal ablation in the transition zone. In addition, there was a distinct interface between viable and necrotic prostatic parenchyma. Histopathologic examination revealed TTC staining-outlined necrotic versus viable tissue. Gadolinium-enhanced MRIs in the cohort of 15 patients demonstrated lesion defects in all patients at 1 week post-procedure. Coalesced lesions were noted with a mean (± standard deviation) lesion volume of 9.6±8.5 cm(3). The largest lesion volume was 35.1 cm(3). Ablation using vapor was rapid and remained confined to the transition zone, consistent with the thermodynamic principles of convective thermal energy transfer.

Conclusion: Thermal ablation was observed in all specimens. The resulting coalescing ablative lesions, as seen on MRI, were confined to the transition zone. These studies confirm the ablative capabilities of vapor, validate the thermodynamic principles of convective heating, and allow for further clinical studies.

No MeSH data available.


Related in: MedlinePlus