RU2266056C2 - Method for urinary tract plasty on its prolonged or relapsing stricture, obliteration or fistula - Google Patents

Abstract

FIELD: medicine, urology.

SUBSTANCE: one should transfer bladder's mucosa subfascially into area for potential flap under development. After mucosal adaptation one should form skin-fascial flap that contains transferred mucosa. One should dissect the altered urethral section and altered paraurethral tissues. Then it is necessary to substitute the defect of urethral wall with flap's mucosa. As for defect of periurethral tissues and skin they should be substituted with the rest tissues of the flap mentioned. The innovation enables to exclude thinning, sclerosing of transferred mucosa and save the strength and elasticity of urethra.

EFFECT: higher efficiency of plasty.

2 ex, 1 tbl

Description

The invention relates to medicine, in particular to urology.

Surgical treatment of extended (more than 3 cm) urethral strictures or obliterations presents significant difficulties due to the need to replace a large portion of the urethra, which is not always possible due to local tissues, or is associated with pronounced anatomical or functional changes (shortening, deformation of the penis). The same difficulty is the treatment of recurrent strictures or fistulas of the urethra, when the resource of local tissues was used in previous operations.

A known method of reconstructing the urethra in such situations (an extended or recurring stricture or urethral obliteration, recurrent urethral fistula), consisting in a microsurgical transplant of a skin-fascial skin fascial flap on an arteriovenous leg, from which a tubular graft is formed that replaces a removed section of the altered urethral canal Scheplev P.A., Adamyan R.G., Abbakumov L.A., Amosov F.R. Subtotal and total urethroplasty in men using free wax larized skin radiation flap. // Urol. and nephrol. - 1996. - No. 3. - p. 36-39). Due to the good main blood supply to the transplanted flap and the microsurgical technique of the operation, a good graft engraftment and tightness of the anastomoses are achieved, which ensures a good functional effect. The disadvantages of this method are reactive changes in the skin of the transplanted flap in response to constant contact with urine, which leads to maceration, chronic inflammation and a gradual narrowing of the lumen of the reconstructed urethra. There is also known a method of flap grafting of the urethra using a free transplant in the form of a “patch” or tubular graft flap of the mucous membrane of the inner surface of the cheek, lip or mucosa of the bladder (Kropfl D., Tucak A., Prlic D., Verweyen A. Using buccal mucosa for urethral reconstruction in primary and re-operative surgery. // Eur. Urol. - 1998. - vol. 34, No. 3. - p. 216-220, Garat JM, Villavicencio H. Posterior urethroplasty with tubularized bladder mucosal graft. // J. Urol. - 1991. - vol. 148. - p. 1615-1617). The advantage of this method is that the urethra is restored by tissue resistant to aggressive media, including urine (especially when using the bladder mucosa), which does not lead to inflammatory changes in the transplanted flap and improves the long-term results of the operation. The disadvantage of this method is the lack of blood supply to the flap in the early period after its transplantation until the blood vessels from the surrounding tissues sprout. Due to this, there is a thinning, sclerosis of the transplanted mucosa, the loss of its strength and elasticity.

The aim of the proposed method is to increase the efficiency of urethroplasty by eliminating these disadvantages of the prototype methods while maintaining their advantages.

This goal is achieved by the fact that at the first stage, the removed mucous membrane of the bladder is transplanted subfascial on the inner surface of the arm into the area that will be further used for the formation of a radiation flap. 1 month after complete engraftment of the mucosa and restoration of its blood supply due to the vessels of the surrounding tissues, a radial skin-fascial flap is formed on the arteriovenous leg with the inclusion of a previously transplanted mucous membrane. This flap is used for plastic surgery of the urethra, and patency and integrity of the urethra is restored due to the mucous membrane, and the skin with subcutaneous tissue and fascia closes the defect of removed pathologically altered periurethral tissues. In this case, blood supply both in the mucous membrane and in the skin-fascial part of the transplant is carried out through anastomosed flap vessels.

The method is as follows. Cystotomy is performed in the traditional way. A section of a mucous membrane of sufficient size is excised, depending on the extent of the urethral defect to be eliminated. A defect in the wall of the bladder is sutured with a catgut suture. The removed flap is washed in physiological saline and stitched on a polyvinyl chloride catheter in the form of a tube with a continuous suture with Vicryl thread 3 / 0-4 / 0. On the inner surface of the forearm in the area of the alleged formation of the radial skin-fascial flap, the fascia covering the muscles is exposed in a small incision, and a formed tubular graft with a catheter is placed in the subfascial space. After 1-1.5 months, a radiation-skin-fascial graft is formed, which includes the bladder that has become accustomed, according to a standard technique, and is used for plastic surgery of the fistula or stricture, or urethral obliteration. In this case, altered sections of the urethral wall or the entire altered section of the urethra, including the area with spongiofibrosis, as well as altered periurethral tissues, are excised. Urethral continuity is restored either by anastomosing a tubular graft of the bladder mucosa with distal and proximal segments, or by suturing a dissected tubular graft to the remaining wall of the urethra as a “patch”. The defect in periurethral tissues and skin is compensated by the remaining tissues of the flap.

The effectiveness of the proposed method is illustrated by examples.

Example 1. Proof of the effectiveness of the proposed method

A 34-kg male mongrel dog had a urethral stricture by excision and electrocoagulation of the ventral wall of the urethra. After 1 month, radiologically clearly revealed narrowing of the urethra in the penoscrotal region for 1 cm. In accordance with the claimed method, a flap of the bladder mucosa 3 × 2 cm in size was removed, a tube was formed from it and transplanted subfascial to the inner surface of the forelimb. 1.5 months after transplantation, a skin-fascial graft was formed, which included a previously transplanted mucosa on an arteriovenous leg. The artery and vein supplying the transplant were bandaged and crossed, and the removed flap was transferred to the urethral plastic area. The graft vessels anastomosed with the artery and vein of the penis, passing to the right of the root of the penis. After they were convinced of a good restoration of the blood supply to the flap and the mucous membrane included in it, the sclerotized narrowed section of the urethra was removed and the defect was eliminated by suturing the tubular transplant with the mucous membrane using a continuous Vicryl 4/0 suture. Sclerotic periurethral tissues and a scarred area of the skin were excised, and the resulting defect was closed with the rest of the flap. The graft skin was stitched with separate interrupted sutures to the surrounding skin. According to the reconstructed urethra, a permanent catheter was inserted into the bladder for 3 days.

Examination of the dog after 1, 6 and 12 months revealed normal urination without signs of infravesical obstruction. When urethrography revealed a wide lumen of the urethra throughout. No signs of stenosis were found in the dynamics. When determining the resistance of the urethra to fluid flow 1 year after surgery, the values of this indicator, significantly increased after the formation of urethral stricture, were completely normalized (normal values - 33.5 srvc. Units, after the formation of stricture - 43.7 srvc. Units, after urethroplasty according to the claimed method - 32.4 conventional units).

This example illustrates the high efficiency of the proposed method and the durability of the obtained functional results.

Example 2. Comparison of the proposed method and prototype methods

In 18 dogs, a stricture or fistula of the urethra was simulated. To do this, a cut at the root of the scrotum exposed the urethra and opened it with a longitudinal cut. After this, a ventral wall defect of 0.1-0.2 × 0.5-0.6 cm in size was formed, bleeding from the spongy tissue was stopped by electrocoagulation, the urethral defect was not closed, and the skin wound was reduced with separate sutures to the size of the urethral defect, sometimes stitching the edges urethra and skin. After 1 month, the dogs were examined radiologically and, with confirmation of the formation of a stricture or urinary fistula, were used in further experiments.

In the 1st series of experiments (6 dogs: 3 with stricture, 3 with fistula), the pathology was eliminated using patchwork of a freely transplanted bladder mucosa (using the prototype method). An abdominal cavity was opened by a cut bordering the penis to the right or left, the bladder was brought into the wound and opened with a longitudinal incision along the ventral surface. A flap measuring 1.0-1.5 cm × 0.5 × 1.0 cm was cut from the mucous membrane and removed, and the resulting mucosal defect and incision of the bladder wall were sutured with catgut. In dogs with urethral stricture along the longitudinal section at the root of the scrotum, the urethra was exposed in the stricture area, it was opened longitudinally, the scarred tissues were excised, and the resulting defect was covered with a “patch” cut out in size from the removed bladder mucosa. On the urethral catheter, the edges of the “patch” and the urethra were anastomosed with a continuous twisted suture with Vicryl 4/0 thread. In the presence of an urethral fistula, it was excised, including a section of the urethral wall. The resulting defect in the urethral wall was closed by the bladder mucosa, as described above. The skin wound was sutured tightly.

In the 2nd series of experiments (5 dogs, 3 of them with fistula and 2 with stricture), urethral pathology was eliminated by microsurgical transplantation of a fascial skin-fascial flap on an arteriovenous leg (prototype method). For this, the brachial artery and vein were isolated on the inner surface of the forelimb in the middle or lower third of the shoulder. We found a sufficiently large arterial branch supplying the skin of this region with the vein accompanying it (artery diameter 0.8-1 mm, vein diameter 1.5-2 mm). By carefully preparing the surrounding perivascular tissues, which was carried out using optical magnification and microsurgical technique, the vascular pedicle of the future transplant was formed, after which the flap itself was formed, dissecting the skin and subcutaneous tissue to the fascia fascia, which was included in the flap. After the complete mobilization of the flap, the stage of operation in the recipient area began. A longitudinal section on the side of the root of the penis distinguished the proximal part of the cavernous bodies and vessels of the penis passing along their dorsal-lateral surface. The artery and vein were thoroughly dissected, the central end of the vessels was pinched with microvascular clips, and the peripheral one was ligated and crossed. The crossed central vascular section was washed with saline with heparin. After the final preparation of the vessels, the urethra was dissected in the stricture area or the fistula was excised with a skin-urethral fistula, while all the visually changed mucous membrane of the ventral wall of the urethra was removed, without fear of a possible narrowing of its lumen when suturing the wall defect. Then, a subcutaneous tunnel was formed connecting the area of the former fistula and the area of the penile vessels. The vessels of the previously formed skin-fascial flap of the forelimb were separately ligated at the junction with the humeral vessels and crossed. The flap was washed through a thin catheter inserted into the artery with saline with heparin and transferred to the recipient area. At the same time, the graft itself was placed in the region of the sutured urethra, and the vascular pedicle was brought out through the subcutaneous tunnel to the vessels of the penis. Microsurgical anastomosing of vessels “end-to-end” with separate interrupted sutures “Prolene” 8 / 0-9 / 0 was performed. After restoration of blood flow in the transplant, a platform was formed from its fascial surface that was equal in size to the defect in the ventral wall of the urethra, with which the defect was closed in the form of a patch using a continuous suture with Vicryl 4/0 thread. After careful hemostasis, subcutaneous tissue and transplanted flap and penis skin were sutured.

In the 3rd series of experiments (7 dogs, 3 of them with stricture and 4 with fistula), the elimination of urethral pathology was performed using the inventive method using a combined flap with the mucous membrane of the bladder. In dogs, a section of the bladder mucosa was removed as described in the 1st series, the removed flap was washed in physiological saline and sewn on a polyvinyl chloride catheter in the form of a tube using a continuous suture with Vicryl 4/0 thread. On the inner surface of the forelimb in the area of the alleged formation of the skin-fascial flap, a fascia covering the muscles was exposed in a small incision, it was opened, and a formed tubular graft with a catheter was placed into the subfascial space. Fascia, subcutaneous tissue and skin were sutured in layers. After 1-1.5 months, a skin-fascial graft was formed, which included the bladder that had survived, as described in the 2nd series, and was used for plastic surgery of the fistula or urethral stricture. In this case, all altered tissues (skin, subcutaneous tissue and urethral wall) were widely dissected, a defect in the urethral wall, formed after excision of the fistula or dissection of the stricture and excision of scars, was closed by the graft mucosa, and the skin defect was eliminated due to the graft skin.

The experimental results are presented in table 1.

Table 1.
Comparison of the results of urethral repair by the claimed method and prototype methods. Series of experiments Number of experiments Relapse of the fistula Stricture Diverticulum Norm Free plastic of the urethra of the bladder mucosa (prototype) 6 0 0 3 3 Plastic surgery of the urethral fistula with a vascularized fascial fascial flap (prototype) 5 1 1 0 3 Plastic of the urethra with a vascularized flap from the bladder mucosa (the claimed method) 7 0 0 0 7

When using a freely transplanted bladder mucosa, there was not a single case of recurrence of fistula or urethral stricture. However, in half of the experiments in the long-term period with urethrography, a more or less pronounced swelling of the transplanted mucosa ("diverticulum") was found, which was apparently associated with a deterioration in the mechanical and elastic properties of the graft. During elimination of the fistula or stricture of the urethra with the help of a microsurgical transplantation of the skin-fascial flap in 2 dogs, thrombosis of vascular anastomoses occurred, which led to a violation of the blood supply to the transplanted flap and its partial necrosis. Subsequently, in 1 of these dogs a relapse of urethral stricture occurred, and in the other, a permanent cutaneous-urethral fistula formed. The remaining 3 dogs achieved a good functional effect. The formation of "diverticula" was not noted. When eliminating a stricture or fistula of the urethra by the claimed method in all experiments, a persistently good functional effect was obtained. There was no relapse of stricture or fistula, despite the fact that in 1 case there was a thrombosis of the graft vessels and its partial necrosis. The "diverticulum" of the urethra was also not observed.

These results confirm the high efficiency of the proposed method and its advantages compared with the prototype methods.

The above examples indicate that the inventive method avoids the disadvantages of existing methods of urethroplasty, combining the advantages of these methods. They consist in the fact that a well-supplied blood flap is used for urethral plasty, which ensures adequate delivery of oxygen and nutrients not only to the tissues of the graft itself, but also to the surrounding tissues, the blood supply of which, as a rule, is disturbed due to chronic inflammation, sclerosis and previous operations. Restoring the integrity of the urethra is carried out using a blood-supplying mucous membrane that is resistant to the aggressive action of urine, which avoids skin imperfections such as maceration of the skin, its chronic inflammation, and hair growth in the lumen of neourethra. Good blood supply to the mucosa allows it to maintain its mechanical and elastic properties, ensures its good engraftment and tightness of the anastomoses, which prevents the development of urinary leakage with subsequent sclerosis of the tissues, leading to relapse of the stricture.

Claims (1)

A method for plastic surgery of the urethra, including microsurgical transplantation of a skin-fascial flap on an arteriovenous leg, characterized in that the mucous membrane of the urinary bladder is subfascially transplanted into the area in which the flap is supposed to be formed and, after its engraftment, a skin-fascial flap containing the transplanted mucosa is formed and use it for plastic surgery of the urethra, while the altered section of the urethra and altered periurethral tissues are excised and replaced a defect in the urethral wall with the mucous membrane, and a defect in the periurethral tissues and skin with the rest of the flap tissues.