(018) Long Term Outcome of Tachosil Patching of the Penile Tunica Albuginea Defect in the Dog: Histological and Hemodynamic Results
Authors: Seyam R , Alhussain T , Abualhasan A , Kattan S , Altaweel W 
Published: March 2024

Abstract

Introduction
The need for patching of the penile tunica albuginea (TA) might arise during surgery for Peyronie’s disease with or without a penile prosthesis. Clinically, TachoSil has evolved as an off-the-shelf hemostatic graft that does not need suturing. Results in patients are encouraging. However, its histopathological fate and its impact on the hemodynamics of erection are not known.

Objective
We evaluate the long-term histopathology and pharmacologically induced erection after Tachosil patching of the TA in dogs.

Methods
Under general anesthesia, the penis of two adult male beagle dogs was dissected through a midline incision, and TA was exposed. The femoral artery was cannulated and connected to an invasive pressure monitor to record BP. Intracavernous pressure (ICP) was measured on each cavernous side separately, as a complete septum isolates the two compartments of the penis. A 21-gauge butterfly needle was placed on either side proximally. Five minutes were allowed before taking baseline ICP. Ten mg of papaverine hydrochloride was injected intracavernosal. ICP was measured at 2 to10-min time points. On the left side, 2 cm proximal to the glans of the penis, a full-thickness defect was created in TA 1 cm long and 0.5 cm wide (Fig. 1. A, B &C). Four transverse incisions 1 cm long were made on the right side and placed 0.5 cm apart, exposing the corpus cavernosum (Fig. 1. D). A Tachosil patch (Takeda, Japan) was fashioned and applied to cover the defects. Proline 5/0 sutures were placed, marking the proximal and distal ends of the graft areas. The fascia, subcutaneous tissue, and skin were closed with absorbable sutures. Six months later, each dog was anesthetized, and the penis was dissected free from the covering fascia. Invasive BP and ICP measurements were repeated at baseline and after 10 mg papaverine injection. Silk and proline sutures were placed to identify the distal end and the left side of the penis. The penis was excised from the base of the glans penis distally to its root, at least 6 cm proximally and fixed in 10% formaldehyde solution. Transverse blocks of the penis were cut at 3 mm intervals and fixed in paraffin. Sections from each block were stained with H&E and trichrome and examined by a urology pathologist. Descriptive statistics are provided.

Results
Gross appearance showed a well-healed scar, and the subcutaneous tissue did not show significant adhesions. The graft site was impossible to distinguish, and the sutures were not visible. ICP measurement did not show a drop in pressure pre- and post-surgery (Fig. 2). Histologically, minimal foreign body reaction was seen, and the tunica albuginea was completely regenerated (Fig. 3). The underlying cavernous tissue did not show inflammation or necrosis.

Conclusions
Long-term histological results of Tachosil patching in the dog show complete tunica albuginea regeneration with minimal tissue reaction and no underlying cavernous tissue pathology. Hemodynamically the intracavernous pressure response to papaverine is maintained. Although only two animals are presented here, the results are striking. Further experimentation with more animals is warranted to support these findings.

Disclosure
No.