Randomized clinical trial Randomized clinical trial of botulinum toxin injection for pain relief in patients with thrombosed external haemorrhoids R. Patti, M. Arcara, S. Bonventre, S. Sammartano, M. Sparacello, G. Vitello and G. Di Vita Department of Surgical and Oncological Science, Division of General Surgery, University of Palermo, Via Liborio Giuffr` e 5, Palermo 90127, Italy Correspondence to: Professor G. Di Vita (e-mail: divitagaetano@libero.it) Background: Thrombosed external haemorrhoids are one of the most frequent anorectal emergencies. They are associated with swelling and intense pain. Internal sphincter hypertonicity plays a role in the aetiology of the pain. This study evaluated the efficacy and safety of an intrasphincteric injection of botulinum toxin for pain relief in patients with thrombosed external haemorrhoids. Methods: Thirty patients with thrombosed external haemorrhoids who refused surgical operation were randomized into two groups. Patients received an intrasphincteric injection of either 0·6 ml saline or 0·6 ml of a solution containing 30 units botulinum toxin. Anorectal manometry was performed before treatment and 5 days afterwards. Results: After 5 days of treatment, the maximum resting pressure fell in both groups, but was significantly lower in the botulinum toxin group (P = 0·004). Pain intensity was significantly reduced within 24 h of botulinum toxin treatment (P < 0·001), but only after 1 week in the placebo group (P = 0·019). Conclusion: A single injection of botulinum toxin into the anal sphincter seems to be effective in rapidly controlling the pain associated with thrombosed external haemorrhoids, and could represent an effective conservative treatment for this condition. Registration number: NCT00717782 (http://www.clinical trials .gov). Paper accepted 15 September 2008 Published online in Wiley InterScience (www.bjs.co.uk). DOI: 10.1002/bjs.6236 Introduction Thrombosed external haemorrhoids (TEH) are one of the most frequently diagnosed anorectal emergencies 1 . They commonly occur in young adult patients of both sexes 2 . Clinically, TEH present with a lump and intense pain. Pain is disproportionately severe given the size of these lesions, the thrombus forming within the lumen of the external haemorrhoidal vessels. External haemorrhoidal thrombosis can be associated with constipation or diarrhoea, but often there is no history of straining or exertion 3,4 . TEH are debilitating, and have an economic impact because of time off work, cost of medication and reduction in quality of life. The pain and lump may take several days or weeks to resolve and symptoms may be incapacitating. Internal anal sphincter hypertonicity has a role in the pain associated with TEH and is responsible for the The Editors are satisfied that all authors have contributed significantly to this publication maximum resting anal pressure (MRP), but few studies have measured the MRP in patients with TEH. Shafik demonstrated increased electromyographic activity in the internal anal sphincter associated with TEH, and pain relief afforded by a warm Sitzbath was associated with relaxation of the internal anal sphincter 5 . Some drugs that act by reducing internal anal sphincter tone have proved effective in the conservative treatment of TEH. In 1995, Gorfine reported complete or nearly complete pain relief within 2–3 min after the administration of 500–1000 mg 0·5 per cent nitroglycerin ointment to patients with TEH 3 . Pain relief was temporally associated with a decline in anal pressure 3 . In a more recent trial, topical application of 0·2 per cent glyceryl trinitrate (GTN) ointment was compared with incision and excision. Pain relief achieved by excision was significantly greater than that achieved by incision or GTN treatment 6 . In a randomized open comparison of topical therapy with lidocaine alone versus lidocaine plus 0·3 per cent nifedipine ointment, addition of nifedipine Copyright  2008 British Journal of Surgery Society Ltd British Journal of Surgery 2008; 95: 1339–1343 Published by John Wiley & Sons Ltd Downloaded from https://academic.oup.com/bjs/article/95/11/1339/6142679 by guest on 06 June 2022