Ureteral reconstruction with abdominal wall muscle flap: experimental study in rabbits

Abstracts

The authors detail the experimental development of a technique for the reconstruction of the ureter using a tubular shape, muscle flap of the abdominal wall. the preliminary results indicate the feasibility of this surgical technique.

Ureter; Surgical Flap; Abdominal Wall

Os autores detalham o desenvolvimento experimental de uma técnica para a reconstrução do ureter, utilizando um retalho muscular da parede abdominal, na forma tubular. O resultado preliminar indica a viabilidade desta técnica operatória.

Ureter; Retalhos Cirúrgicos; Parede Abdominal

INTRODUCTION

Traumatic lesions of the ureter are relatively frequent events and may be caused by iatrogenic lesions, most often after gynecological or urological operations, or after blunt or penetrating abdominal trauma. Some techniques can be employed for the treatment of such lesions, ranging from uretero-enterostomy to ileal interposition^{1 - 4}. Muscle flaps have long been experimentally studied as substitutes for segments of the urinary tract⁵.

In this study we describe a ureteral reconstruction technique using a myoperitoneal flap made with elements of the abdominal wall.

TECHNIQUE

We used six New Zealand White, male rabbits, weighing 3 kg. The anesthetic medication consisted of ketamine (35 mg/kg) and xylazine (5 mg/kg) intramuscularly in the pre-anesthesia, followed by general anesthesia induction and maintenance with inhaled isoflurane and 100% oxygen in an open system.

Upon completion of a suprapubic laparotomy and dissection of the ventral abdominal wall, we manufactured a pedicled muscle flap, irrigated by the epigastric vessels, with approximately 3 cm wide and 5 cm in length (Figure 1).

Figure 1 -
Pedicled muscle flap, with epigastric vessel (arrow).

The flap was shaped in a tubular fashion over a catheter, so that the inner surface was aponeurotic, and the peritoneal surface, external. Then, after resection of approximately 0.5 cm from the dorsal bladder wall, the bladder was anastomosed to the distal end of the muscle tube.

After section of the ureter at the junction of the middle third with the distal one, we catheterized the ureter cranially with a 1 mm-diameter polypropylene catheter, so that it was positioned inside the muscular tube, reaching the bladder. Then, to reestablish the urinary transit, we sutured the cranial segment of the ureter to the proximal opening of the muscular tube (Figure 2).

Figure 2 -
Tunneled muscle flap (TMF) sutured to the bladder (B) and to the remaining segment of the ureter (U).

We administered analgesics postoperatively for five days and observed the animals' body posture. We daily performed surgical wound inspection and palpation of the abdomen in the the renal fossa area to assess the kidney size. We also observed the appearance and quantity of urine. We performed autopsy on the 60th day of the postoperative period, with on-site verification of the urinary structures.

This project was approved by the Ethics Committee on Animal Use - CEUA - Experimental Surgery Laboratory, Department of Surgery, Faculty of Medicine, Federal University of Rio de Janeiro - FM-UFRJ.

DISCUSSION

Ureteral injury is a complication that can occur after any abdominal or pelvic surgery, or endoscopic maneuver^{1 , 2}.

Its treatment varies depending on the affected ureteral segment and the functional status of renal unit^{2 , 3}. Depending on the injured segment, various ureteral reconstruction techniques can be used^{3 , 4}. In cases of severe tissue devitalization or compromise of a large ureteral segment, extreme measures are necessary, such as the renal autograft or ileal transposition^{4 , 6}, which can replace a segment or the entire ureter^{7 - 12}.

In this study, the application of pedicled muscle flap from the abdominal wall set in a tubular form for the partial reconstruction of the ureter was adequate. On examination of the surgical wound we did not observe infection or dehiscence. There was the emergence of incisional hernia in the donor area of the pedicled muscle flaps, the urine showed normal appearance and color, and the animals urinated normally. At necropsy, there was preservation of the anatomical structures and sustained permeability of the lumen of the muscular tube.

Thus, according to the results obtained in this study, the use of a tunneled muscle flap of the abdominal wall for the partial replacement of a ureteral segment is a viable technique and can be an alternative in the reconstruction of ureteral segments.

REFERENCES

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  Smith N, Medeiros M, Vieira G. Complete ureteral avulsion: ileal ureteral substitution wth an unusal proximal ileal anastomosis. BJUI [Internet]. 2010 Dez. Disponível em: http://www.bjui.org/contentfullitem.aspx?Id=586.
  » http://www.bjui.org/contentfullitem.aspx?Id=586

• Source of funding: none.

Publication Dates

• Publication in this collection
  Nov-Dec 2014

History

• Received
  02 Feb 2014
• Accepted
  05 May 2014