Evangelos Ioannidis

Corporoplasty using tunica albuginea free grafts for penile curvature: surgical technique and long-term results.

PURPOSE A Nesbit or plication procedure for correcting penile deformities is associated with penile shortening, especially in patients with excessive curvature and/or rotation. On the other hand, grafting procedures are associated with poor postoperative results due to graft shrinkage and veno-occlusive dysfunction. To minimize penile shortening and preserve potency we describe a new surgical technique combining the Nesbit procedure with tunica albuginea free grafting. Long-term functional results and patient satisfaction are reported. MATERIALS AND METHODS We treated 17 potent patients with a mean age plus or minus standard deviation of 46.1 +/- 14.5 years, including 4 with congenital penile deviation and 13 with stabilized Peyronies disease. Opposite the point of maximal curvature a typical Nesbit procedure was performed. The excised tunica albuginea segment consequently served as a free graft. A symmetrical incision was made at the opposite site and the preserved elliptical tunica albuginea graft was placed in the defect. Further elliptical excisions and grafting followed as needed to correct the deformity. RESULTS At a mean followup of 39.5 +/- 13.7 months (range 18 to 62) all patients reported penile straightening and functional erection, while ultrasonography of the corpora cavernosa revealed no changes in graft ultrastructure. There was penile shortening in 8 patients (47%) but only 2 (11.7%) considered it significant. All patients with a minimum 2-year followup were positive in regard to recommending the operation to others or repeating it if necessary. CONCLUSIONS The newly described technique may be considered as a treatment option in patients with excessive penile curvature since shortening of the penile shaft is eliminated by 50% compared with the result of the Nesbit procedure. Tunica albuginea seems to be an appropriate grafting material since it prevents postoperative corporeal veno-occlusive dysfunction.

Hemodynamic Characterization of a Functional Erection

Objectives: To characterize hemodynamically a functional/rigid erection and study the hypothesis that a positive intracavernosal injection test indicates normal arterial and corporeal veno-occlusive function. Methods: 33 patients (mean age 39.5 ± 9 years), who developed rigid erection during pharmacocavernosometry, included in the present study. The presence of axial rigidity was determined at steady state equilibrium intracavernosal pressure, by absence of buckling to axial force of 1 kg, applied to the erect penis and sustained for ≥15 min. Arterial and veno-occlusive hemodynamic parameters were analyzed. Results: Flow-to-maintain at intracavernosal pressure 150 mm Hg and mean pressure decay values ranged between 0.5–13 ml/min and 5–85 mm Hg, respectively. Flow-to-maintain values >5 ml/min were noticed in 8 patients (24.24%), while pressure decay values >45 mm Hg in 13 patients (39.39%). Pharmacocavernosography revealed moderate opacification of venous structures in 7 cases (21.21%). Abnormal systemic-cavernosal systolic arterial pressure gradients in both cavernosal arteries were noticed in 9 patients (27.27%). All patients with flow-to-maintain values >5 ml/min had normal arterial function. Conclusions: A functional/rigid erectile response may coexist with arterial insufficiency or corporeal veno-occlusive dysfunction. Presence of normal or borderline arterial inflow may compensate minimal or moderate veno-occlusive dysfunction, resulting in a functional – but not normal – erection. Such information is critical when the intracavernosal injection test is used for diagnostic purposes.

Normal hemodynamic parameters do not always predict the presence of a rigid erection: a quantitative assessment of functional erectile impairment

The purpose was to assess objectively and quantitatively the hemodynamic status and the degree of functional erectile impairment in a group of impotent patients. A clinical study was designed, incorporating pharmacocavernosometry (to evaluate arterial and veno-occlusive function) with axial buckling forces and penile geometry measurements in a group of impotent patients. The pressure gradient between the intracavernosal pressure associated with the presence of penile axial rigidity and the equilibrium intracavernosal pressure was calculated (axial rigidity gradient, ARG); such methodology allowed a quantitative characterization of functional impairment, as ARG expresses the intracavernosal pressure increase necessary to achieve axial rigidity and therefore potency. Penile geometry characteristics were also expressed by calculating the penile aspect ratio (diameter/length, D/L). In 83 consecutive patients tested (mean age 42.89±9.96), rigidity occurred at intracavernosal pressures between 50 and 100 mm Hg. A conversely proportional relation was noticed between penile aspect ratio values and the intracavernosal pressure associated with rigidity values, clearly demonstrating the important functional role of penile geometry. ARG demonstrated a wide range of values (3–69 mm Hg), reflective of the severity of the erectile dysfunction on each patient. Half (50.6%) of the patients had ARG values ≤20 mm Hg, indicative of minimal and minimal-to-moderate erectile impairment, while 20.48% had ARG between 21–30 and 28.92% >30 mm Hg, indicative of moderate and severe erectile dysfunction (ED) respectively. In all, 6% of the study group, all of them with primary ED, ARG <20 mm Hg had normal hemodynamics, but low penile aspect ratio values indicating that penile geometry may be the cause of insufficient rigidity. Hemodynamic integrity is the most critical, but not the only determinant of penile rigidity, as erectile impairment may be noticed in patients with normal arterial inflow and corporal veno-occlusive function. In such cases, unfavorable penile geometry should be considered as the possible etiological factor of impotence.

Age and Time Operator of Evolutionary Processes

The Time Operator and Internal Age are intrinsic features of Entropy producing Innovation Processes. The innovation spaces at each stage are the eigenspaces of the Time Operator. The internal Age is the average innovation time, analogous to lifetime computation. Time Operators were originally introduced for Quantum Systems and highly unstable Dynamical Systems. The goal of this work is to present recent extensions of Time Operator theory to regular Markov Chains and Networks in a unified way and to illustrate the Non-Commutativity of Net Operations like Selection and Filtering in the context of Knowledge Networks.