Does tunica anatomy matter in penile implant?

Abstract

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.

Keywords: Tunica albuginea in human penis (TA in human penis); penile implant; prosthesis extrusion; prosthesis loss.

Figure 1

Schematic illustration of the fibrous skeleton in the human penis. The tunica albuginea of the corpora cavernosa (CC) is a bilayered structure in which the inner circular layer completely contains the sinusoids and, together with the intracavernosal pillars, supports them. There is a paucity of outer layer bundles at the region between the 5 and 7 o’clock positions where there is close contact with the corpus spongiosum. Distally, they are grouped into the glans penis forming the distal ligament, located at the 12 o’clock position of the distal urethra. The median septum is incomplete with dorsal fenestration at the pendulous portion of the penis and is completed where the penile crura are formed.

Figure 2

Photos of approaches for penile implant. (A) A circumferential approach was used for a 52-year-old diabetic male for implanting Duraphase. Note a further penile elongation (arrow) was revised owning to noticeable loss of penile length; (B) an extended pubic incision was marked (arrow) and prepared for implanting an AMS700CX in a 57-year-old man; (C) the penile implant was finished while the wound was fashioned (arrow).

Figure 3

Illustration and photos of the related architecture for penile implant. (A) Vascular distribution of human penis in relation to the fibrous skeleton which is majorly composed of tunica albuginea. Note the distal ligament which is stout and strong; (B) A median section of the distal penis discloses the relation of the tunica and corpora cavernosa (CC). A thicker tunica on the dorsal aspect is pronounced, whereas a much thinner coat is noted on the ventral aspect. Note the large distal ligament; (C) A cross section of the distal CC. A paucity of outer longitudinal layer was characteristic between the five and seven o’clock positions which is much thinner and spreads out distally; (D) Illustration of cross section of mid-portion of the TA. The relationship between the TA and intracavernosal pillars was depicted. The room one and two are sound to house the prosthesis cylinder, but neither room three nor room four.

Figure 4

X-ray films of penile prosthesis in situ. (A) An AP view discloses a distal migration (left, dotted arrow) of an acuform prosthesis in a 76-year-old male; (B) oblique view offers a clearer demonstration. Note the extender (dotted arrow) migrates proximally. Oblique view offers a clearer demonstration. Note the extender (dotted arrow) migrates proximally; (C) an AP view of an AMS600 discloses a discrepancy of bilateral CC length in a 66-year-old diabetic man. Note his left cylinder wears no extender and a dilatation could not reach to the ischial tuberosity; (D) oblique view gives a clearer demonstration which shows wider gap between the wire and the ischial tuberosity; (E) an AP view of an AMS600 discloses a wire ready to disruption (dotted arrow) in an 86-year-old diabetic man. Note his CC is symmetrical length; (F) Oblique view shows a clearer demonstration which shows the penis is unable to remain neutral position. AP, anterior-posterior; CC, corpora cavernosa.

Figure 5

X-ray films of a 45-year-old male with penile prosthesis. (A) An AP discloses a complete disruption (arrow) of the right wire and an incomplete disruption of the wire (dotted line) in the left side both side cylinder in an AMS600; (B) however in an oblique view, the wire of left CC is complete disrupted (arrow), in the left side, there is a complete disruption (arrow) in addition to the incomplete disruption (dotted arrow); (C) a revision surgery was performed for implanting a Spectra prosthesis. This AP view discloses a sound implantation; (D) this oblique view further demonstrates prosthesis in good fashion. AP, anterior-posterior; CC, corpora cavernosa.