The Value of Injection Therapy with Botulinum Toxin in Pain Treatment of Primary Chronic Anal Fissures Compared to Anal Dilation, and Local Nifedipine in Combination with Lidocaine

Introduction: Anal fissure is a longitudinal tear of the mucosa of the anal canal extending from the outer anal orifice in the direction of the dentate line of the inner anal opening. Fissures are divided into primary and secondary, and acute or chronic. Besides minimal rectal bleeding, itching and soiling, primary chronic anal fissures (PCAF) manifest with anal pain as theirs main determinant. It is described as the most troubling symptom. Aim: To compare the effect of injection therapy with botulinum toxin A (ITBT) vs. anal dilation (AD), and local nifedipine with lidocaine (LNL) in pain treatment of PCAF. Materials and Methods: This controlled retrospective prospective longitudinal study covered 94 patients, divided in 3 groups. The first was treated with ITBT, the second with AD and third using LNL (31, 33 and 30 patients respectively). Clostridium botulinum toxin A was used, dissolved with saline to concentration of 200 U/ml. The solution was applied to both sides of PCAF at dose of 40U. Modified technique of AD was done using 3 fingers of a single hand, progressively introduced into the anal canal, followed by gradual lateral distraction during 1 min. LNL therapy was conducted using nifedipine (0.3%) with lidocaine (1.5%) ointment, applied twice daily for 3 weeks. To measure pain, a visual analog scale (VAS) was used. The follow-up period was 12 weeks with checkup at week 4. Results: The median age of participants was 46.6±13.9 years (50 males vs. 44 females). The type of therapy had a significantly different effect on pain at week 4 (p=0.0003). Severe pain was present in only 2 ITBT patients, 16 AD, and 6 LNL patients. Post hoc analyses showed different pain disappearance time by week 12 (p <0.0001). The mean time was shortest in ITBT group (6.1±1.5 weeks). Anal pain intensity significantly differed among the 3 groups (Fisher exact, p=0.002). Namely, 71% in ITBT group rated the pain as weakest (VAS score 1) compared to 18.2% in AD and 30% of patients in LNL group. The overall pain reduction significance was in favor of ITBT, due to the differences between the ITBT and AD groups (p=0.00024) and ITBT compared to LNL group (p=0.018). Conclusion: ITBT is superior to AD and LNL in reducing pain in PCAF.