Geng-Long Hsu

Advances in understanding of mammalian penile evolution, human penile anatomy and human erection physiology: Clinical implications for physicians and surgeons

Summary Recent studies substantiate a model of the tunica albuginea of the corpora cavernosa as a bi-layered structure with a 360° complete inner circular layer and a 300° incomplete outer longitudinal coat spanning from the bulbospongiosus and ischiocavernosus proximally and extending continuously into the distal ligament within the glans penis. The anatomical location and histology of the distal ligament invites convincing parallels with the quadrupedal os penis and therefore constitutes potential evidence of the evolutionary process. In the corpora cavernosa, a chamber design is responsible for facilitating rigid erections. For investigating its venous factors exclusively, hemodynamic studies have been performed on both fresh and defrosted human male cadavers. In each case, a rigid erection was unequivocally attainable following venous removal. This clearly has significant ramifications in relation to penile venous surgery and its role in treating impotent patients. One deep dorsal vein, 2 cavernosal veins and 2 pairs of para-arterial veins (as opposed to 1 single vein) are situated between Buck’s fascia and the tunica albuginea. These newfound insights into penile tunical, venous anatomy and erection physiology were inspired by and, in turn, enhance clinical applications routinely encountered by physicians and surgeons, such as penile morphological reconstruction, penile implantation and penile venous surgery.

Penile Veins Are the Principal Component in Erectile Rigidity: A Study of Penile Venous Stripping on Defrosted Human Cadavers

The human erectile mechanism is an intricate interplay of hormonal, vascular, neurological, sinusoidal, pharmacological, and psychological factors. However, the relative influence of each respective component remains somewhat unclear, and merits further study. We investigated the role of venous outflow in an attempt to isolate the key determinant of erectile function. Dynamic infusion cavernosometry and cavernosography was conducted on 15 defrosted human cadavers, both before and after the systematic removal and ligation of erection-related penile veins. Preoperatively, an infusion rate of more than 28.1 mL/min (from more than 14.0 to 85.0 mL/min) was required to induce a rigid erection (defined as intracavernosal pressure [ICP] exceeding 90 mmHg). Following surgery, we were able to obtain the same result at a rate of 7.3 mL/min (from 3.1 to 13.5 mL/min) across the entire sample. Thus, we witnessed statistically significant postoperative differences (all P ≤ .01), consistently elevated ICP, lower perfusion volumes, and a general reduction in time taken to attain rigidity. The cavernosograms provided further evidence substantiating the critical role played by erection-related veins, whereas histological samples confirmed the postoperative integrity of the corpora cavernosa. Given that our use of cadavers eliminated the influence of hormonal, arterial, neurological, sinusoidal, pharmacological, and psychological factors, we believe that our study demonstrates that the human erection is fundamentally a mechanical event contingent on venous competence.

Penile vascular surgery for treating erectile dysfunction: Current role and future direction.

Abstract Penile vascular surgery for treating erectile dysfunction (ED) is still regarded cautiously. Thus we reviewed relevant publications from the last decade, summarising evidence-based reports consistent with the pessimistic consensus and, by contrast, the optimistically viable options for vascular reconstruction for ED published after 2003. Recent studies support a revised model of the tunica albuginea of the corpora cavernosa as a bi-layered structure with a 360° complete inner circular layer and a 300° incomplete outer longitudinal coat. Additional studies show a more sophisticated venous drainage system than previously understood, and most significantly, that the emissary veins can be easily occluded by the shearing action elicited by the inner and outer layers of the tunica albuginea. Pascal’s law has been shown to be a significant, if not the major, factor in erectile mechanics, with recent haemodynamic studies on fresh and defrosted human cadavers showing rigid erections despite the lack of endothelial activity. Reports on revascularisation surgery support its utility in treating arterial trauma in young males, and with localised arterial occlusive disease in the older man. Penile venous stripping surgery has been shown to be beneficial in correcting veno-occlusive dysfunction, with outstanding results. The traditional complications of irreversible penile numbness and deformity have been virtually eliminated, with the venous ligation technique superseding venous cautery. Penile vascular reconstructive surgery is viable if, and only if, the surgical handling is appropriate using a sound method. It should be a promising option in the near future.

Reconstructive surgery for idealising penile shape and restoring erectile function in patients with penile dysmorphology and erectile dysfunction.

Abstract Objective: To report an innovative combination of two surgical procedures to treat patients with erectile dysfunction and penile deviation, arising from advances in penile anatomy. Patients and methods: From October 1998 to October 2011, 132 men (aged 23–39 years) underwent penile venous stripping and corporoplasty. Of these, 37 were allocated to a transverse and 95 to a longitudinal group, with an infrapubic transverse or pubic median longitudinal approach, respectively. The abridged five-item version of the International Index of Erectile Function (IIEF-5) and cavernosography were used for assessment, as necessary. Under acupuncture-aided local anaesthesia, and after a circumferential incision, the deep dorsal vein and cavernous veins were completely stripped, with 6-0 Nylon sutures for ligation, followed by tunical surgery for correcting the penile shape. Results: In the transverse and longitudinal groups the mean (SD) duration of surgery was 4.6 (0.2) and 4.8 (0.3) h, respectively. Before surgery the mean (SD) IIEF-5 score was 9.4 (2.3) and 9.6 (2.1), which increased to 20.6 (2.4) and 20.8 (2.7), respectively, after surgery. The penile shape (<15°) was deemed satisfactory in 92% (34/37) and 96% (91/95) of patients in the transverse and longitudinal groups, respectively. The cavernosograms consistently showed a good penile shape. There were significant differences in the mean (SD) duration of penile oedema, at 3.2 (1.6) vs. 11.9 (2.1) days, the overall satisfaction rate and the prevalence of hypertrophied scarring (all P < 0.001). Conclusion: This combination of unique penile venous stripping with a pubic median longitudinal approach and an anatomy-based corporoplasty is ideally suited to the simultaneous restoration of penile erectile function and morphological reconstruction.

Venous ligation: a novel strategy for glans enhancement in penile prosthesis implantation.

Although penile implantation remains a final solution for patients with refractory impotence, undesirable postoperative effects, including penile size reduction and cold sensation of the glans penis, remain problematic. We report results of a surgical method designed to avoid these problems. From 2003 to 2013, 35 consecutive patients received a malleable penile implant. Of these, 15 men (the enhancing group) were also treated with venous ligation of the retrocoronal venous plexus, deep dorsal vein, and cavernosal veins. The remaining 20 men formed the control group, treated with only a penile implant. Follow-up ranged from 1.1 to 10.0 years, with an average of 6.7 ± 1.5 years. Although preoperative glanular dimension did not differ significantly between the two groups, significant respective difference at one day and one year postoperatively was found in the glanular circumference (128.8 ± 6.8 mm versus 115.3 ± 7.2 mm and 130.6 ± 7.2 mm versus 100.5 ± 7.3 mm; both P<0.05), radius (38.8 ± 2.7 mm versus 37.1 ± 2.8 mm and 41.5 ± 2.6 mm versus 33.8 ± 2.9 mm; latter P<0.01), and satisfaction rate (91.7% versus 53.3%, P<0.01) as well. Based on our results, selective venous ligation appears to enhance the glans penis dimension in implant patients.

The venous drainage of the corpora cavernosa in the human penis.

Abstract Objective: To study the drainage proportions from the corpora cavernosa in defrosted human cadavers, as the veins related to penile erection were recently depicted to comprise the deep dorsal vein (DDV), a pair of cavernous veins (CVs) and two pairs of para-arterial veins (PAVs), as opposed to a single DDV between Buck’s fascia and the tunica albuginea of the human penis. Materials and methods: With no formalin fixation, 10 defrosted male human cadavers were used for this study. After injecting a 10% solution of colloid, and with the intracavernous pressure (ICP) fixed at 90 mmHg, the perfusion rate was recorded before and after the DDV, CVs and PAVs were removed, respectively. Finally, measurements were again recorded after penile arterial ligation. Cavernosography was used if required. Results: The mean (range) perfusion rate for maintaining the ICP at 90 mmHg was 30.2 (15.5–90.8) mL/min, whereas the arterial perfusion rate was 2.8 (0.3–3.9) mL/min. The mean (range) drainage proportion of the corpora cavernosa was 60.5 (50.3–69.7)%, 11.9 (5.8–22.9)% and 11.4 (5.2–15.0)% via the DDV, CVs and PAVs, respectively. The remaining drainage proportion was 15.6 (14.1–18.1)%. This study shows the separate drainage contributions of the DDV, CVs and PAVs to the corpora cavernosa of the human penis. Conclusion: We conclude that the venous drainage system of the corpora cavernosa is much more complex than the previous depictions of it, and the consequent focus on a single DDV. This also shows the independent role of each venous system.

Herb formula enhances treatment of impotent patients after penile venous stripping: a randomised clinical trials

Herbs have been regarded as aphrodisiacs in treating impotence for many centuries despite little true scientific evidence. Our latest refined penile venous stripping (PVS) technique is effective in treating impotence, although this procedure remains controversial. A synergic effect of PVS and oral herbs was confirmed in our practice but lacked rigorous scientific proof. The objective of this report was to review our experience with this combination. From August 2010 to May 2014, 263 males underwent PVS. Among these, 67 unsatisfied men chose additional salvage therapy and were randomly assigned to oral herbs (n = 35) or placebo treatment (n = 32) which replaced herb eventually. All were evaluated with the international index of erectile function (IIEF‐5) scoring and our dual pharmaco‐cavernosography. The pre‐op IIEF‐5 score for the herb group was 9.7 ± 3.7, post‐operative 13.9 ± 3.3 and post‐herb 19.6 ± 3.4, while the control group scores were as follows: pre‐op 9.3 ± 4.1, post‐op 14.5 ± 3.6, post‐placebo 15.1 ± 3.5 and post‐herb 19.9 ± 3.2. Although there was no significant difference between the two groups pre‐operatively, post‐operatively and post‐herb, a statistically significant difference was found post‐salvage therapy (19.6 ± 3.4 versus 15.1 ± 3.6, P < 0.001). It appears that the combination of oral herbs and PVS treatment provides an enhanced outcome to impotent patients refractory to medicine and unsatisfied with PVS monotherapy alone.

Acupuncture assisted local anesthesia for penile surgeries.

Although the mechanism of acupuncture for analgesia is not fully elucidated, a combination of acupuncture and several methods of topical blocks for local anesthesia has been effective to patients with indications for penile surgeries on ambulatory basis. We sought to review this unique clinical application since 1998. To summarize practice-based medical literature contingent this unique application and, in contrast, the commonly agreed either general or spinal anesthesia concerning those surgeries on this most sensitive organ—the delicate penis. From July 1998 to July 2013, total of 1,481 males underwent penile surgeries with specific topical nerve blockage in addition to acupuncture in which the acupoints of Hegu (LI4), Shou San Li (LI10), Quchi (LI11), and either Waiguan (TE5) or Neiguan (PC6) were routinely used. Careful anesthetic block of the paired dorsal nerve in the penile hilum associated with a peripenile infiltration was categorized to method I which is sufficient to anesthetize the penile structures for varied penile surgeries including 993 men of penile venous stripping surgeries, 336 cases of penile corporoplasty, 8 males of urethroplasty, 7 patients of vaso-vasostomy, 6 men of penile arterial reconstruction and 3 surgeries of penectomy. Whereas the bilateral cavernous nerve block and crural blockage were indispensably added up for anesthetizing the sinusoids of the corpora cavernosa (CC) for penile implant of varied model. It was allocated to method II and had been applied in 125 males. A further topical injection of the medial low abdominal region made it possible for implanting a three-piece model in three males. Thus recent discoveries and better understanding of the penile anatomy had been meaningful in the development and improvement of specific nerve blockade techniques for penile surgeries in particularly adding up with acupuncture techniques, while minimizing anesthetic adverse effects and resulting in a rapid return to daily activity with minimal complications.

A Combination of Penile Venous Stripping, Tunical Surgery and Varicocelectomy for Patients with Erectile Dysfunction, Penile Dysmorphology and Varicocele under Acupuncture-aided Local Anesthesia on Ambulatory Basis

Background: Since 1986, we have refined our combination of penile venous stripping, corporoplasty and varicocelectomy which has proven to be efficacious to patients who suffer from the combination of Erectile Dysfunction (ED), Penile Deviation (PD) and varicocele. It has been developed in tandem with the advances in our understanding of the penile venous, tunical and related anatomy. Herein we sought to report on an approach utilizing the combination of three surgeries for reversing ED, restoring libido and revitalizing the age-related decline in sexual performance. Materials and methods: From June 2010 to March 2012, a total of 35 men, aged from 41 to 49 years, with ED resulting from Veno-Occlusive Dysfunction (VOD), penile deviation and a varicocele. Twenty three (the surgical group) underwent a combination of penile venous stripping, morphological reconstruction and varicocelectomy. Twelve were assigned to the control group. The abridged five-item version of the International Index of Erectile Function (IIEF-5) was used to score the patients. Furthermore, a dual cavernosogram, a prostaglandin E-1 test and a life quality rating were used to assess patients at 6 month intervals. Under an innovative method of acupuncture-aided local anesthesia, and following a circumferential incision, the Deep Dorsal Vein (DDV) and Cavernosal Veins (CVs) were completely stripped and ligated, followed by a pubic median longitudinal skin incision for completing the venous vasculature removal. Tunical surgery was then performed for correcting penile shape. Finally, along the longitudinal pubic wound, a unilateral or bilateral varicocelectomy was performed via a subcutaneous tunnel. Results: The follow-up period ranged from 0.5 to 2.5 years. In the surgical group the average operation time was 4.8 ± 0.3 h. There was no postoperative infection. The preoperative IIEF-5 and the life quality ratings were 9.6 ± 2.1 and 27.3 ± 4.5%, which was increased postoperatively to 20.6 ± 2.3 and 80.8 ± 6.4% respectively (both p<0.001). Whereas in the control group the corresponding preoperative IIEF-5 and life quality ratings were 9.8 ± 2.5 and 29.4 ± 4.4% respectively, in the equivalent postoperative period these changed to 8.8 ± 2.7 and 20.8 ± 6.5% respectively (both p<0.01). The difference between the two groups (p<0.001) and within the group (p<0.01) was significant. A satisfactory penile shape was achieved in 21 (91.3%) patients with 2 men (8.7%) complaining of mild residual deviation of the penis (<10°). Postoperative frenulum edema was limited (3.2 ± 1.6 days). Cavernosograms also demonstrated the ideal milieu of the corpus cavernosum for retaining intracorporeal fluid/blood. Conclusion: A combination of penile venous stripping, penile morphological reconstruction and varicocelectomy provides a novel solution for reestablishing satisfactory and satisfying sexual functioning and performance.

Does tunica anatomy matter in penile implant

Background Overall prosthesis survival is important in penile implant, which remains the final viable solution to many patients with refractory erectile dysfunction (ED). This paper is to retrospectively study the role of the anatomy of tunica albuginea (TA). Methods From March 1987 to March 1991 while the TA was regarded as a circumferential single layer, 21 organically ED men, aged from 27 to 77, received penile prosthesis implantation and were allocated to conventional group. From August 1992 to March 2013 while the tip of Hegar’s dilator was categorically directed medial-dorsally during corporal dilatation derived from newfound TA as a bi-layered structure with a 360° complete inner circular layer and a 300° incomplete outer longitudinal coat, 196 ED males, aged from 35 to 83, underwent penile implant and were categorized to advanced group. The model of prosthesis was recorded. Prosthesis loss rate and survival time were analyzed and the follow up period ranged from 22.4-26.4 (average 24.3) years and 0.4-20.6 (average 15.8) years to the conventional and advanced group respectively. Results To the conventional and advanced group, the number of inflatable and rigid type prosthesis used were 2, 19 and 15, 181 respectively, whereas the prosthesis loss was encountered in 50.0% (1/2), 15.8% (3/19) and 0.0% (0/15), 0.6% (1/181) respectively. And the prosthesis survival time were 5.1-6.3 (5.7) years, 1.3-26.4 (15.2) years and 6.1-16.2 (11.2) years, 0.4-20.6 (15.3) years to the conventional and advanced group respectively. Statistical significance was noted on prosthesis loss in groups (P=0.01) while the Mentor Acuform stood out in prosthesis survival. Conclusions Anatomy-based managing maneuver appears to deliver better surgery success in penile implant. Tunica anatomy is significant in performing implant surgery.