Transcutaneous needle-free injection of botulinum toxin: a novel treatment of childhood constipation and anal fissure.

PURPOSE: Constipation is a common problem in children, and when it becomes chronic fecal impaction, overflow soiling and megarectum may develop. Children with chronic idiopathic constipation (IC) may not respond to conventional treatments of laxatives, enemas, and toilet training. The aims of the study were to evaluate the long-term outcome of transcutaneous needle-free injection of botulinum toxin (TNFBT) into the external anal sphincter (EAS) and to assess the extent of the toxin penetration into the sphincter.

METHOD: Children were recruited if symptomatic with chronic constipation, soiling, painful defecation, and withholding behavior requiring disimpaction of stool and rectal biopsy under general anesthesia. A total dose of 200 U of botulinum toxin (BT) (Dysport; Ipsen Limited, Slough, United Kingdom) was injected transcutaneously into the EAS at 3 and 9-o'clock positions using J-tip needle-free syringes (National Medical Products Inc, Irvine, Calif). The depth and width of toxin penetration was assessed by endosonography. Outcome was measured by a validated symptom severity (SS) score questionnaire. The total SS score ranged between 0 (best) and 65 (worst). The outcome was compared with 31 children in a comparable historical control group at 3 and 12-month follow-up.

RESULTS: Sixteen children were recruited with median age of 6.11 (range, 3-14.85) years and median duration of symptoms of 3.9 years (1.6-11.5). On endosonography, the median depth and width of BT penetration was 8 (7-10) mm and 8 (6-10) mm, respectively. At 3-month follow-up, the median SS score improved in all children after TNFBT from 32.50 (5-57) to 7.50 (0-26) (Wilcoxon's P < .0001). There were significant improvements in symptoms of constipation, soiling, painful defecation, general health and behavior, and fecal impaction of rectum (P < .05). Anal fissures healed in all 4 children. The SS score in the control group improved from 33 (12-49) to 15 (0-40) (P < .0001). At 12-month follow-up, the improvement of SS score in TNFBT group was significantly more than the control group as follows: 4 (0-25) vs 15 (0-51), respectively (Mann-Whitney U P < .002). Three patients had a second TNFBT injection for relapsed symptoms. There were no complications. The transcutaneous needle-free injection of botulinum toxin eliminates the risk of intravascular injection or needlestick injury. The transcutaneous needle-free injection of botulinum toxin also has other therapeutic applications including an alternative therapy to biofeedback training for dyssynergia of the EAS, treatment of muscle limb spasticity in cerebral palsy, and cosmetic treatment of overactive facial muscles and wrinkles and hyperhydrosis.

CONCLUSION: Transcutaneous needle-free injection of botulinum toxin into the external anal sphincter is a novel and safe new treatment of chronic idiopathic constipation and anal fissure in children. A second injection may be required in 20% of patients.