Current Management of Chronic Anal Fissure Joint Hospital Grand Round Department of Surgery,North District Hospital and Alice Ho Mui Ling Nethersole Hospital, NTEC

Anal Fissure Definition: An elongated ulcer in the long axis of lower anal canal

Pathology A split of anoderm Associated with anal skin tag and hypertrophied anal papilla Occur at midline just distal to dentate line 90% posterior, 10% anterior with less than 1% simultaneous

Presenting Sym. Pain Bleeding Discharge Constipation

Examination Gentle eversion of anus with limited digital examination Anoscopy and rigid sigmoidoscopy under anaesthesia or deferred till healing occur Anomanometry is not useful

Differential Dx. Fissure occurs out of midline Carcinoma of anus Inflammatory bowels Tuberculous ulcer HIV/Herpes Biopsy should be taken for ulcer out of mid line or those fail to heal

Anorectal Physiology Continence is maintained when intrarectal pressure are lower then the pressure generated by the resting internal and external sphincters.

Anorectal Physiology Internal Sphincter: Smooth muscle Innervated by sympathetic (excitatory) and parasympathetic fibre; (inhibitory) Constant contraction 85% of resting tone

Pathophysiology

Pathophysiology Great pain associated with initial bowel motion Patient ignores the urge to defecate Allows harder stool to form Self-perpetuating cycle

Management good bowel habit Relieve internal anal sphincter spasm

Management Conservative: to regulate bowel habit, break the self-perpetuating cycle Stool softener Bulk forming agent Sitz-bath 90% healing rate (1 st epsiode) 60% healing rate for recurrent

Management Sphincterotomy to break the vicious cycle induced sphincter spasm to reduce anoderm ischemia and to promote healing

Management Conventional surgical sphincterotomy versus chemical sphincterotomy

Surgical sphincterotomy Lateral internal anal sphincterotomy Open v.s. Close Fissurectomy with anoplasty: reserved for cases with prominent skin tag/recurrent anal fissure Longer healing time

Results and complication Open Close P value Persistence 3.4% 5.3% 0.27 Recurrence 10.9% 11.7% 0.77 reoperation 4% 0.70 Lack of control of gas 30.3% 23.6% 0.06 Soiling 26.7% 16.1% <0.001 Accidental BM 11.8% 3.1%

Surgery good healing rate…… but rather high complication Alternatives?

Sphincterotomy-chemical Chemical sphincterotomy Nitrogylcerin ointment Botulinum toxin injection Ca channel blocker/steriod……

Nitrogylcerin ointment As a source of nitric oxide Inhibitory neurotransmitter cause internal anal sphincter relaxation Commonly used 0.2-0.3% nitroglycerin Local application by patient twice daily for 6/52

Result Healing rate :60-75% Side effect: 15-40% headache

Result N=44 0.2% isosorbide dinitrate surgery 5 weeks healing rate 67% 96% 10 weeks healing rate 89% 100% 30% decrease of maximal anal pressure in both arms side effect 30% headache 15% incontinence Parellada C et al. Randomized, prospective trial comparing 0.2 percent isosorbide dinitrate ointment with sphincterotomy in treatment of chronic anal fissure; a two years follow-up. Dis Colon rectum. 2004 ;47(4) 437-43

Botulinum Toxin Mechanism of action: Action on internal anal sphincter as shown in manometric studies( reducing both the resting and squeezing pressure) Exact mechanism uncertain; inhibit acetylcholine release into synaptic gap causing neuormuscular blockade More sustained action then Nitroglycerin ointment

How to inject? Botulinum toxin A Target: internal anal sphincter as palpated No local anesthetic nor sedation required

How to inject? at least 15 unit ? Probably better in multiple punture Minguez M et al. Theraputic effects of different doses of botulinum toxin in chronic anal fissue Dis Colon Rectum. 1999 Aug;42(8):1016-21

Where to inject? anterior injection of the internal anal sphincter resulted in improved lowering of resting anal pressure and produced an earlier healing Maria G et al. Influence of botulinum toxin site on healing rate in patients with chronic anal fissure. Am J Surg. 2000; 179(1):46-50.

Result: Fissure healing rate: 70-90% at 2 months Recurrence/non healing: 20% No major side effect;

Giuseppe Brisinda and Maria G et al. A comparison of botulinum toxin and topical nitroglycerin ointment for the treatment of chronic anal fissure N Engl J Med1999;341(2): 65-68

Result RCT comparing comparing Botulinum vs Nitroglycerin ointment Higher fissure healing rate at 8 weeks in Botox group 96% vs 60% Significant lower resting anal pressure in Botox group

B.Bulent Mentes et al. Comparison of Botulinum toxin injection and lateral internal sphincterotomy for the treatment of chronic anal fissure Dis Colon Rectum 2002. 46(2) 232-37

N=111 Surgery Botox Fissure healing rate at 2 months 82% 73.8% At 6 months 98% 86.9% recurrent 11.4% Return of daily activities 14.8 days 1 day complication 16%

Conclusion: Internal anal sphincter spasm is the key to tackle chronic anal fissure Traditional lateral sphincterotomy give excellent result in terms of fissure healing but bearing significant risk of incontinence

Conclusion Result of chemical sphincterotomy is satisfactory, without the complication of lateral sphincterotomy and should be consider the first line treatment. Botox injection give the most reliable result among different methods of chemical sphincterotomy