The use of rotational fluoroscopy and 3-D reconstruction in the diagnosis and surgical planning for complex cloacal malformations

Abstract

IntroductionCloacal malformations, a confluence of the urinary tract, vagina and rectum into a single common channel, has a broad and complex anatomic spectrum requiring an imaging tool for visualization, measurement, and surgical planning for the reconstruction of these structures. We evaluated the role of 3-D fluoroscopy for this purpose, as it offers a combination of spatial correlation with precise anatomic measurements. MethodsWe examined our imaging protocol for patients with a cloacal malformation and report our experience with rotational fluoroscopy and 3-D reconstruction in 16 consecutive patients referred for cloacal reconstruction. The length of the common channel (CC), the length of the urethra from the bladder neck to the common channel, and the height (and existence or absence) of a vagina or vaginas were determinants of the surgical procedures used for the repair. ResultsWe performed 16 consecutive 3-D cloacagrams (age range 4 months to 9 years) using a new protocol (Figure 1) that provided the following data which helped with surgical planning: Gynecologic: 3 cases with a single vagina, 5 cases with a duplicated Mullerian system (3 of which were asymmetric) and 2 cases with high vaginas requiring vaginal replacement. Colorectal: Four had a high rectum requiring an abdominal approach, and 6 had a rectum reachable via a posterior sagittal approach. Urologic: Two ectopic ureters requiring reimplantation, 3 patients had vesicoureteral reflux (1 bilateral, 2 unilateral), 1 patient had no bladder, and 7 had a normal sized bladder. Common channel length and urethral length were demonstrated in all cases and used to decide between a total urogenital mobilization or a separation of vagina(s) from the common channel, urogenital separation. ConclusionThe 3-D cloacagram can help predict the surgical plan for urologic, gynecologic, and colorectal components of the cloacal repair. It can predict the CC length as well as the length of the urethra. It helps with predicting the need for vaginal replacement and whether an abdominal approach is needed for the rectum. Its effectiveness is based on the ability to adequately distend structures and see their distal most extent, an advantage over other modalities such as MRI. Added benefits (particularly from the 3D view) include a better spatial understanding of the defect and the diagnosis of concomitant urological abnormalities such as vesicoureteral reflux and ectopic ureters. Disadvantages to this procedure include the need for general anesthesia and a higher exposure to radiation. Level of evidence3.