The feasibility of using an endoluminal device for intestinal lengthening.

PURPOSE: Prior studies demonstrating the ability to lengthen intestinal segments with mechanical force required devices with extracorporeal components. The feasibility of using a completely implantable device for in vivo intestinal lengthening was evaluated in this study.

METHODS

Biocompatible Nitinol springs capable of 5-fold expansions were compressed using absorbable sutures and were implanted into isolated segments of proximal jejunum in rats. Springs compressed with nonabsorbable sutures served as controls. The animals were observed with serial abdominal x-rays until the springs became fully expanded. Intestinal segments were then retrieved for histologic analysis. Two-tailed and paired Student's t tests were used for statistical analysis.

RESULTS

Intestinal segments were successfully lengthened in the experimental group from 1.3 +/- 0.3 cm to 4.4 +/- 0.5 cm (P < .001). Maximum spring length was achieved on postoperative day 36 (range, 16-50 days). In the control group, there was also an increase in intestinal lengths, from 1.6 +/- 0.04 cm to 2.9 +/- 0.4 cm (P < .001) (Fig. 4). In percentages, a 250% increase in length was observed in the experimental group vs an 85% increase in the control group (P < .001). Microscopic evaluation of both control and experimental segments revealed gross preservation of intestinal architecture; however, muscular layer hypertrophy and villous atrophy were noted.

CONCLUSIONS

Continuous mechanical force with an implantable spring successfully lengthened isolated segments of small bowel in an animal model. Although similar results have been demonstrated using other devices, the current device is totally implantable and may be deployed endoscopically.