Unilateral versus bilateral sphincterotomy:A randomized chronic fissure in ano

Chronic anal fissure (CAF) is a linear ulcer of the lower part of the anal canal. It is a characterized by post defecation pain and bleeding. It is associated with internal anal sphincter (IAS) spasm and the relief of internal anal sphincter spasm is the key for providing fissure healing[1]. The therapy of choice for treatment of chronic anal fissure is partial lateral internal anal sphincterectomy.[1,2] However it is associated with risks of infection, bleeding, and incontinence[2].

The rationale for doing UIS is that the internal sphincter is formed by circular muscle fibers and cutting at one point of the circle opens up and relaxes the whole sphincter completely. Therefore, cutting at one or two places should not matter. There is no detailed study available which has evaluated the role of Bilateral internal sphincterotomy in CAF. The aim of this study was to do a randomized controlled trial comparing unilateral internal sphincterotomy (UIS) with bilateral internal sphincterotomy (BIS) and assess the effect on outcome variables like healing of fissure, incontinence and relief in pain.

Patients and methods

220 cases were recruited from 01 Jan 04 to 31 Aug 06 (Figure 1, Consort Flow chart) Eligibility criteria were: Adult patients > 18 years with a history of CAF for more than oneyear. The exclusion criteria were: previous ano-rectal surgery, oral medication of nitrates and calcium channel blockers, as they are known agents for internal sphincter relaxation, and multi-parous women with old perineal tear. Diagnosis was based on clinical anal examination. Presence of sentinel piles was noted. No anal manometer study was done. The nature of study was explained to the patients and the study was received consent from the ethics committee. Randomization was done by by sealed envelope method . No bowel preparation was done. The surgeries were done under local infiltration of a mixture of 10 ml 2% Xylocaine, 10 ml 0.5% Bupivacaine, 5 ml of 7.5% sodium bicarbonate and 10 ml Normal saline, supplemented with 2 mg/Kg of intra-venous Propofol as initial dose followed by aliquots of 10 mg subsequently if required . In lithotomy position, digital examination and proctoscopy was done to confirm the diagnosis (Figure 2a) and rule out any other pathology. Any sentinel papilloma if present was excised. UIS was done at 3 ‘O’ clock and BIS at 3 and 9 ’O’ clock position. 2-3 mm incision was made and dilated with a curved haemostat (Figure 2b). With the guidance of left index finger in the anorectal lumen, the tight felt internal sphincter was hooked out side (Figure 2c) and transected. The sentinel piles and papilloma (Figure 2d) excision completed the procedure. Only external perineal pressure was used for haemostasis.

All patients were observed overnight for any bleeding and pain. Post operatively, all received normal diet and oral tinidazole 500 mg 12hrly for 5 days to decrease the faecal anaerobic load. Oral analgesic (diclofenac sodium 50 mg)and Lactulose 30 ml was advised as and when required. All the patients were advised to take seitz bath for 10-15 minutes three times a day for 2 weeks. They were advised out patient review at 2 weeks, one, three and six months from the date of surgery and if required thereafter. The review at two weeks and three months was a must for inclusion in the study by the patient. Postoperative pain was evaluated on a subjective basis by asking the patient relief in pain on a scale of 0-100 (rupee scale). This was denoted as percentage of pain. Any incontinence was evaluated by two independent doctors at the two week review on the basis of subjective history and perianal soiling. Healing of fissure was studied at three months

Statistical analysis

The Statistical software SPSS 11.0 and Systat 8.0 were used for the analysis of the data. Student t test has been used to test the significance of mean values between Group A(UIS) and Group B (BIS). Analysis of recurrence, second surgery and incontinence were analyzed by Fisher Exact test. Pain parameters were analyzed by two tailed independent student t test. p value < 0.05 was considered as significant .

Results

Of 220 patients evaluated for participation in the study , 104 were randomized to UIS ( group A) and 107 were randomized to BIS ( group B). The two groups of patients were comparable in terms of age (p-0.9) and sex (p-0.9). (Table 1). Five patients in unilateral group had severe postoperative pain. Opposite side sphincterotomy was done in three and inflamed skin tags were excised in two, which relieved the pain. In the UIS group significantly more patients had recurrence of fissure and the analgesic requirement as well as the need for second surgery was also significantly higher.

Discussion

Chronic anal fissure is treated by a variety of medications which may include botulinum toxin as local injection and bran as laxative. But medical therapy in CAF is marginally better than placebo, and far less effective than surgery[3]. CAFA with lower anal pressure are more likely to heal following treatment with 20 units of botulinum toxin[4]. But CAF with the low anal pressure is in any case more conducive for faster healing as healing is dependent on anal pressure[1]. Sphincterotomy gives better results than [5] and does not compromise fecal continence in 6 years[6,7]. Both open and closed partial LIS are equally efficacious[5]. Recurrence after UIS done under local anaesthesia may be higher and females who have two or more previous vaginal deliveries should be warned about possible incontinence to flatus[8]. Open sphincterotomy under local anesthesia takes longer time for healing [9]. The present study combines the advantage of both open and closed method, in the form of small incision and identifying the white smooth muscle of IAS outside the wound like the open method before cutting. The third advantage is of feeing the tight IAS and picking up the spasmodic portion of IAS selectively. UIS causes a significant decline in the resting anal pressure which gradually recovers but still remains significantly lower than ususal but no patient in the present study had incontinence[10]. The weakeness of this study remains that anal manometery was not done. Manometry equipment is not available at our center. A sphincterotomy up to the dentate line results in quick fissure healing but more incontinence. While a sphincterotomy up to apex of fissure leads to no incontinence, however, the rate of healing is low and the recurrence rate is higher[11]. This possibly means a tight lower sphincter is the cause persistence of CAF and the upper part of sphincter may be responsible for the continence. In this study, the sphincterotomy was much more selective, as only the spasmodic portion was cut with the guidance of the anorectal index finger mostly around dentate line. Sparing of the upper part of IAS in this procedure, which is difficult by this method to bring it out, may be the reason for the low rate of incontinence. Only a small number of cases in this study had incontinence to flatus during the initial 2 weeks, and none had liquid or semisolid faecal incontinence corresponding to Cleveland Clinic Incontinence score of good continence (1 to 3 /21)[2]. Internal anal sphincter consists of 20-30 flat rings of smooth muscle bundles stacked like the slats of a Venetian blind, each covered by its own fascia. They coalesce at three equidistant points around the anal canal to form three columns that extend distally into the lumen and differ in form from the other anal columns[13]. Bilateral internal sphincterotomy released at least two coalesced arc of the internal bundles and possibly made the cut more complete. Hence, BIS relaxes the sphincter more than UIS leading to less postoperative pain. The healing process takes almost 6 months and patients with CAF show an improvement in quality of life 6 months after internal lateral sphincterotomy[14].

As compared to UIS, BIS leads to faster healing of CAF with no increase in incontinence. The pain score decreases significantly more after BIS and the recurrence rates are lower.

Acknowledgement

I am grateful to Dr Manoj Kumar and Dr S Anand for help rendered during the peripoerative care and follow up. I also extend my thanks to Dr. V.A. Saraswat who was anaesthesiologist during the surgical procedure.

References

1. Suknaiæ S, Patrlj L, Steresiniæ M, Skopljanac Macina A, Erdelez L Surgical or biologic sphincterotomy in the treatment of chronic anal fissure. Acta Med Croatica. 2008;62:73–80.

2. Kang GS, Kim BS, Choi PS,Kang DW. Evaluation of healing and complications after lateral internal sphincterotomy for chronic anal fissure: marginal suture of incision vs. open left incision: prospective, randomized, controlled study. Dis Colon Rectum. 2008;51:329–33.

3. Nelson R.A systematic review of medical therapy for anal fissure. Dis Colon Rectum. 2004;47:422–31.

4. Thornton MJ, Kennedy ML, King DW. Prospective manometric assessment of botulinum toxin and its correlation with healing of chronic anal fissure. Dis Colon Rectum. 2005;48:1424–31.

5. Thornton MJ, Kennedy ML, King DW. Prospective manometric assessment of botulinum toxin and its correlation with healing of chronic anal fissure. Dis Colon Rectum. 2005;48:1424–31.

6. Brown CJ, Dubreuil D, Santoro L, Liu M, O’Connor BI, McLeod RS. Lateral internal sphincterotomy is superior to topical nitroglycerin for healing chronic anal fissure and does not compromise longterm fecal continence: six-year follow-up of a multicenter, randomized, controlled trial. Dis Colon Rectum. 2007;50:442–8.

7. Nelson R. Operative procedures for fissure in ano. Cochrane Database Syst Rev. 2005;18;(2):CD002199.

8. Casillas S, Hull TL, Zutshi M, Trzcinski R, Bast JF, Xu M. Incontinence after a lateral internal sphincterotomy: are we underestimating it? Dis Colon Rectum. 2005;48:1193–9.

9. Sánchez Romero A, Arroyo Sebastián A, Pérez Vicente F, Serrano Paz P, Candela Polo F, Tomás Gómez A, et al . Open lateral internal anal sphincterotomy under local anesthesia as the gold standard in the treatment of chronic anal fissures. A prospective clinical and manometric study. Rev Esp Enferm Dig. 2004;96:856–63.

10. Ram E, Alper D, Stein GY, Bramnik Z, Dreznik Z. Internal anal sphincter function following lateral internal sphincterotomy for anal fissure: a long-term manometric study. Ann Surg. 2005;242:208–11.

11. Mente BB, Ege B, Leventoglu S, Oguz M, Karadag A. Extent of lateral internal sphincterotomy: up to the dentate line or up to the fissure apex? Dis Colon Rectum. 2005;48:365–70.

12. Rockwood TH, Church JM, Fleshman JW, Kane RL, Mavrantonis C, Thorson AG, et al. Patient and surgeon ranking of the severity of symptoms associated with fecal incontinence: the fecal incontinence severity index. Dis Colon Rectum. 1999;42:1525–32.

13. Uz A, Elhan A, Ersoy M, Tekdemir I. Internal anal sphincter: an anatomic study. Clin Anat. 2004;17:17–20. Ortiz H, Marzo J, Armendariz P, De Miguel M. Quality of life assessment in patients with chronic anal fissure after lateral internal sphincterotomy. Br J Surg. 2005;92:881–5

14 Ortiz H, Marzo J, Armendariz P, De Miguel M. Quality of life assessment in patients with chronic anal fissure after lateral internal sphincterotomy. Br J Surg. 2005;92:881–5.