Rectal biopsy: what is the optimal procedure?

Abstract

Rectal suction biopsy (RSB) is a well-known diagnostic procedure for disorders of bowel motility such as Hirschsprung's disease (HD). However, there are few reports about the optimal method of obtaining rectal tissue. We introduce a new technique using Gruenwald's nasal cutting forceps (NCF). From 1986 to 1999, we performed 130 sets of rectal biopsies in patients suspected of having HD. In group I (1986 to 1994), 68 sets of three-site biopsies (2, 3, and 5 cm above the dentate line) were performed using a conventional blind RSB technique. In group II (1995 to 1999), 62 sets of one-site biopsies (2 cm above the dentate line) were performed using Gruenwald's NCF after anal dilatation during general anesthesia. Hematoxylin-eosin staining and acetylcholinesterase histochemistry were used to examine all specimens. Biopsy specimens in group II (4.39 +/- 1.07 mm(2)) were larger than in group I (1.59 +/- 0.39 mm(2)) ( P < 0.01). In 18 cases (26 %) in group I, normal and HD bowel could not be differentiated because the specimens were too small to detect ganglion cells (i.e., only lamina propria [9 cases] or a small area of submucosa [9 cases] was present). These cases required repeat biopsy. All cases of HD diagnosed in group I (n = 20) were based on the findings of biopsies taken at 2 cm; biopsies from 3 and 5 cm did not provide additional information. There were 2 cases of post-biopsy hemorrhage in group I. In group II, 18 subjects were diagnosed with HD and 39 were confirmed to have normal bowel. There were no complications and repeating the biopsy was unnecessary. Three cases of hypoganglionosis (1 in group I and 2 in group II) were missed because the myenteric plexus abnormalities could not be detected by RSB. Intestinal neuronal dysplasia (IND) was diagnosed in 5 cases (2 in group I by repeat full-thickness biopsy and 3 in group II by rectal biopsy). We conclude that our new technique is advantageous and safe to differentiate between normal bowel, HD, and even IND on the basis of a single biopsy taken 2 cm above the dentate line. The biopsy can be taken under direct vision and is histopathologically accurate.