Daniel Rodríguez B, et al. GÉNITOURINARIO Usefulness of multidetector computed tomography in the postoperative evaluation of urinary diversion surgery Daniel Rodríguez B(1), Richard Mast V(1), Albert Pons E(1), Eugenia de Lama S(1), Francesc Vigués J(2), Oscar Natoli V(1). 1. Radiology Department, Hospital Universitaria de Bellvitge, L´Hospitalet de Llobregat. Barcelona - España. 2. Urology Department, Hospital Universitaria de Bellvitge, L´Hospitalet de Llobregat. Barcelona - España. Abstract: Urinary diversion surgeries are procedures that are becoming more frequent, as their indications are not only neoplastic, being useful also in managing other diseases. Due to this increase, it is not uncommon to observe secondary complications, whether in the early postoperative period (less than 30 days after surgery) or later (more than 30 days). Within these are alterations in intestinal motility (paralytic ileus, blockage), anastomotic leaks, fluid collections (lymphocele, urinoma, abscess), fistulas, parastomal herniation, ureteral obstruction, urolithiasis and tumor recurrence. Given the large number of surgical techniques used in these procedures, it is important to know the resulting anatomical changes, occasionally difficult to evaluate. Multidetector computed tomography (MDCT) is of great use in the study of these patients, especially with multiplanar reconstruction techniques, adequately representing the affected urinary and extra-urinary structures, and their relationship to adjacent structures, enabling their accurate and quick identification. Keywords: Cystectomy, Multidetector computed tomography, Postoperative complications, Urinary diversion. Resumen: Las cirugías de derivación urinaria son procedimientos que cada vez son más frecuentes, ya que sus indicaciones no son sólo neoplásicas, siendo también útiles en el manejo de otras patologías. Debido a este incremento, no es infrecuente observar complicaciones secundarias, ya sean en el postoperatorio temprano (menos de 30 días después de la cirugía) o tardío (más de 30 días). Dentro de éstas tenemos alteraciones de la motilidad intestinal (íleo paralítico, obstrucción), fugas anastomóticas, colecciones líquidas (linfocele, urinoma, absceso), fístulas, herniación paraestomal, estenosis ureterales, litiasis y recurrencia tumoral. Dada la gran cantidad de técnicas quirúrgicas usadas en estos procedimientos, es importante conocer los cambios anatómicos resultantes, ocasionalmente de difícil valoración. La tomografía computarizada multidetector (TCMD) tiene gran utilidad en el estudio de estos pacientes, especialmente mediante las técnicas de reconstrucción multiplanar, representando adecuadamente las estructuras urinarias y extraurinarias afectadas, y sus relaciones con estructuras adyacentes, permitiendo identificarlas acertada y rápidamente. Palabras clave: Cistectomía, Complicaciones postquirúrgicas, Derivación urinaria, Tomografía computarizada multidetector. Rodríguez D, et al. Utilidad de la tomografía computarizada multidetector en la evaluación postoperatoria de cirugías de derivación urinaria. Rev Chil Radiol 2014; 20(2): 68-74. Correspondence: Daniel Rodríguez Bejarano / [email protected] Paper received 03 March 2014. Accepted for publication 22 May 2014. Introduction Criteria for choosing a technique are: patients age, The main indication for radical cystectomy is a general condition, curative vs. palliative character of bladder tumor which invades muscle (T2 or greater) the surgery, renal function, tumor stage, intestinal or at high risk of invasion, without metastasis. Less pathology, previous RT, among others(1). common indications include neurogenic bladder, in- Due to the large number of existing techniques, terstitial cystitis (IC) or lesions from radiation therapy the correct interpretation of postoperative radiological (RT). At present there are various surgical techniques findings is complicated. In order to achieve a correct for urinary diversion, which are usually complex. diagnosis, the knowledge of surgical techniques and 68 Revista Chilena de Radiología. Vol. 20 Nº 2, año 2014; 68-74. GÉNITOURINARIO postoperative anatomy, is essential. This article illus- uroexcretory system we will place the patient in the trates the surgical techniques most used for performing prone or lateral position depending on the affected urinary diversion, describing the normal postsurgical system; this change in the position of the patient is changes and complications derived thereof. performed if their baseline conditions permit. Surgical techniques The surgical techniques used can be divided into continent and incontinent. The first consists in making reservoirs from intestinal segments (ileum). These circular shaped reservoirs are made using incisions in the antimesenteric edge of the loop, in order to avoid physiological peristalsis that increases the pressure within the reservoir and, hence, urine leaks can occur. To perform these types of procedures, the patient must have adequate renal function that can compensate for the metabolic acidosis that the urine may cause on the intestinal segment used as a reservoir. In this regard, the ileum has more advantages compared to the colon, since it presents less risk of acidosis, supports higher urinary volumes and allows shorter resections than the colon. Among the continent pro- cedures, the most performed in our institution is the Figure 1. Coronal CT reconstruction that shows in excretory Studer technique. The incontinents, of heterotopic phase both uroexcretory systems and the entero-ureteral character, are used more widely in our environment anastomosis with the Bricker loop more distally (arrowhead). and within them are nephrostomy, ureterostomy, ileal ureterostomy (Bricker), cystostomy, among others(1-4). Early complications (<30 days after surgery) Bowel transit disorders: These are caused by the Radiological evaluation presence of adynamic ileus or bowel obstruction. The Before performing a study, the radiologist specia- use of MDCT with multiplanar reconstructions allows lizing in urological pathology should know the normal identification of the cause of the obstruction, with a postoperative anatomy of the urinary diversion surgeries. sensitivity of 90-96% and a specificity of 96% in the The anatomy changes depend on the type of diversion, diagnosis of complete obstructions(7,8). The ileus is showing, for example, the extension of the ureters usually secondary to small bowel manipulation during at the ureteroileal anastomosis and the ileal conduit surgery. It presents in 20%, and appears as a uniform towards the skin in the Bricker technique (Figure 1), dilatation of bowel loops with air-fluid levels within, the formation of an ileal reservoir and the formation of witn no identifiable obstructive causes (Figure 2)(2). a “chimney” where the ureters anastomose (Studer), In the obstruction, dilation of the loops proximal to the ureters are anastomosed to the abdominal wall the obstruction site occurs. In this case the loops (ureterostomy), among others(4-5). MDCT is a useful in vicinity to the entero-enteric anastomosis and tool that allows a rapid assessment of the urinary tract. usually due to the presence of adhesions, are not It also allows the use of multiplanar and 3D volumetric visible using this technique, being a diagnosis of reconstructions that allow the correct identification of exclusion (Figure 3). When this complication occurs, extra-urinary complications (e.g. paralytic ileus, fluid it is necessary to reoperate the patient(1,8,9). collections) and without interference with intestinal air/gas, which would not be visible using techniques such as intravenous urography(6). 2a 2b In our hospital, where we have two units of MDCT, the study technique commonly used consists of a triple phase after IV administration of iodinated contrast. The first phase is in portal phase (65 seconds), then late phase (180 seconds) and finally an ultra late phase of between 8 and 15 minutes to detect late leaks in the entero-ureteral anastomosis. Very occasionally an arterial phase is added in cases of suspected bleeding or vascular complication. All these image acquisitions Figure 2. Adynamic ileus. MDCT axial (a) and coronal are performed with the patient in supine position, (b) shows generalized dilatation of small bowel loops with except when we find functional delay or ectasia in contrast inside, width unchanged. 69 Dr. Daniel Rodríguez B, et al. Revista Chilena de Radiología. Vol. 20 Nº 2, año 2014; 68-74. 3a 3b 5a 5b Figure 3. Intestinal occlusion. MDCT axial (a) and coronal Figure 5. Urinoma in the form of a polylobulated fluid (b) showing generalized dilatation of small bowel loops up collection in right hemipelvis (arrow). Volume is located to a certain point, where abrupt change in width can be to the enteroureteral anastomosis and urinoma diagnosis seen (arrows) in the postoperative hernia. was confirmed by fine needle aspiration and secondly on performing evacuation by drainage. Urinary leakage: A rare complication (1-4%)(10). For a correct diagnosis we must be able to rely on 6a 6b single phase, corticomedullary and excretory. The latter phase is of importance to observe contrast extravasation by the ileal conduit or the neobladder, being more usual at the level of the ureteral-reservoir anastomosis (Figure 4)(1,11). 4a 4c Figure 6. Recently postoperative (Bricker) patients who presented pelvic hematoma (arrow) in image a) and subcutaneous fluid collection compatible with seroma (arrowhead)