Purpose: To develop a phantom with optical and thermal properties matched to human prostate. This phantom will provide a platform for the development and characterization of 980nm laser interstitial thermal therapy (LITT) systems. Methods: A polyacrylamide gel was doped with Naphthol Green B, Intralipid, and Bovine Serum Albumin (BSA). The necessary concentration of each ingredient was determined by measuring the optical properties via fluence measurements and light diffusion theory. LITT was then performed under the same conditions as a previous clinical trial in which temperature was monitored via a thermal probe. The thermal data and induced coagulation zone were compared to clinical data to illustrate the similarity between the phantom and patient. LITT was also performed under magnetic resonance thermometry (MRT). Results: The requisite concentrations of Naphthol Green B, Intralipid and BSA were found to be 0.144% (w/v), 8.06% (v/v) and 31.4% (v/v) respectively. In the native state, the absorption coefficient and reduced scattering coefficient (μs′) were found to be 0.66 ± 0.06 cm−1 and 8.27 ± 0.50 cm−1 respectively, with μs′ increasing to 17.63 ± 1.41 cm−1 after coagulation. The thermal response of the phantom was similar to that observed clinically with maximum thermal probe measurements of 64.2°C and 66.9°C respectively. The shape of the induced coagulation zone was qualitatively and quantitatively similar to the MRT zone of elevated temperature and the coagulation zone observed clinically. Conclusions: A phantom which simulates optical and thermal response to 980nm LITT was constructed and demonstrated to be similar to human prostate.

Background: Peyronie's disease (PD) can be subdivided into acute and chronic phases. Intralesional collagenase Clostridium histolyticum has been shown to improve curvature in the chronic phase. Initial clinical trials excluded patients in the acute phase from treatment. Recent studies show comparable results among men in the acute phase. The definition of acute phase varies among existing studies, but it is generally understood to last 12-18 months and is accompanied by penile pain and progression of deformity. We sought to evaluate the safety and efficacy of intralesional collagenase injection therapy during the acute phase of PD using multiple definitions of the acute phase.Methods: All men receiving intralesional collagenase for PD from October 2015 through December 2020 at a single academic institution were retrospectively assessed for patient demographics and comorbidities, pre-and post-treatment curvature, and adverse events. Two definitions of acute phase were used: (I) acute phase duration ≤6 months, chronic phase duration >6 months; and (II) acute phase duration ≤12 months with penile pain, chronic phase duration >12 or no penile pain.Results: Of 330 patients identified, 229 underwent intralesional collagenase treatment with pre-and post-treatment erect penile goniometry. 65 (28%) met criteria for definition 1 of acute phase, 37 (16%) met criteria for definition 2, and 76 (33%) met criteria for either. Percent change in penile curvature was not significantly different between acute and chronic phases using definition 1 (16.0% vs. 16.6%, P=0.89), definition 2 (19.9% vs. 15.7%, P=0.43), or either (16.5% vs. 16.3%, P=0.96). The rates of development of bruising, swelling, hematoma, or corporal rupture were not significantly different between the acute and chronic phases under either definition (all P>0.05).Conclusions: This single-center, retrospective cohort analysis suggests that intralesional collagenase is both safe and effective for the treatment of men with acute phase PD. Limitations exist inherent to retrospective review, since many men did not return for post-treatment goniometry, possibly skewing our cohort toward incomplete responders. Prospective, randomized studies will be required to confirm these findings.

Characterization of Peyronie’s disease (PD) involves manual goniometry and penile length measurement. These techniques neglect volume loss or hourglass deformities. Inter-provider variability complicates accuracy. Using 3D-printed models, we aimed to evaluate measurement accuracy and variability and establish computational assessment workflows. Five digital phantoms were created: 13.0 cm cylinder, 13.0 cm hourglass cylinder, 15.0 cm cylinder with 40° angulation, 12.0 cm straight penis, and 12.9 cm PD penis with 68° angulation and hourglass. Lengths, volumes, and angles were determined computationally. Each phantom was 3D-printed. Ten urology providers determined lengths, angles, and volumes with measuring tape, goniometer, and volume calculator. Provider versus computational measurements were compared to determine accuracy using t-tests or Wilcoxon rank-sum tests. No significant differences were observed between manual assessment of length of penile models and designed length in penile models. Average curvature angles from providers for bent cylinder and PD phantoms were 38.3° ± 3.9° (p = 0.25) and 57.5° ± 7.2° (p = 0.006), respectively. When assessing for volume, hourglass cylinder and bent cylinder showed significant differences between designed volume and provider averages. All assessments of length, angle, and volume showed significant provider variability. Our results suggest manual measurements suffer from inaccuracy and variability. Computational workflows are useful for improved accuracy and volume assessment.

Background In the original clinical trials evaluating intralesional collagenase Clostridium histolyticum for Peyronie disease (PD), treatment protocols were limited to 8 injections. Aim We sought to describe our single-center experience with the use of multiple rounds (>8 injections) of intralesional collagenase in patients with PD. Methods We conducted a retrospective analysis of all patients with PD receiving intralesional collagenase injections at our institution from October 2015 through December 2020. Some patients who completed 1 round of treatment elected to undergo additional rounds (16 or 24 injections) based on persistent curvature and presence of penile plaque. Clinical improvement was defined as a 20% reduction in penile curvature from the start of a given round of treatment to the end of that round of treatment. We measured erect penile curvature before and after each round and collected demographics, medical and surgical history, curvature outcomes, and treatment-related adverse events. Outcome The primary outcome was the reduction in penile curvature after multiple rounds of treatment with intralesional collagenase injections in patients with PD. Results A total of 330 patients underwent intralesional collagenase injections for PD, of whom 229 completed at least 8 injections and underwent pre- and posttreatment erect penile goniometry. An overall 42.8% (98/229), 38.6% (22/57), and 12.5% (1/8) of patients achieved clinical improvement after 1 round of therapy (8 injections), 2 rounds (16 injections), and 3 rounds (24 injections), respectively. Mean degree and mean percentage improvement of penile curvature for the start and end of each round of treatment were 8.3° and 16.4% (after 1 round), 7.2° and 16.8% (after 2 rounds), and 3.3° and 8.1% (after 3 rounds). Bruising was the most common complication, with an incidence of at least 50% in each round. Clinical Implications Knowledge of patient responses to multiple rounds of intralesional collagenase injections may help guide physicians in management and counseling of patients regarding PD treatment options. Strengths and Limitations This is the first study to evaluate multiple rounds (>8 injections) of intralesional collagenase for PD. Limitations include retrospective analysis and smaller sample size among patients undergoing 3 rounds (24 injections). Conclusion For patients who did not achieve clinical improvement after 1 round of treatment, an additional round may be beneficial. However, no real improvement was observed for patients undergoing a third round.

Purpose: The safety label for collagenase Clostridium histolyticum was updated to include postinjection acute lower back pain as an adverse event observed with intralesional therapy for Peyronie's disease. Incidence and causality are unknown. We assessed frequencies and temporal associations for this adverse event in a large cohort. Materials and Methods: Data on all men undergoing collagenase injections for Peyronie's disease at our institution from October 2015 through December 2020 were retrospectively assessed. The study included 330 patients, 300 completing at least 1 full course (8 injections). Measured outcomes included incidence and timing of back pain, and associations with demographics and comorbidities. Results: Of 330 patients, 19 (5.8%) experienced at least 1 episode of postinjection acute lower back pain. Of 300 who completed at least 1 full course of 8 injections, 4 (1.3%) reported back pain within the 8-injection course. A subset underwent additional rounds (16 or 24 injections). Back pain increased to 8.7% (13/149) during a second round, 6.9% (3/43) during a third. No association was found with age, diabetes or back pain history. Most cases occurred shortly after injection; all were self-limited or resolved with a single dose of ketorolac. Conclusions: This single-center, retrospective analysis suggests that intralesional collagenase injections for Peyronie's disease may cause acute lower back pain in up to 6% of patients. Patients may benefit from counseling regarding this risk. Incidence rises with additional rounds of treatment. Prospective safety data regarding >8 injections do not exist. No patient had long-term sequelae of back pain.