It is only in the last few years that it has been recognized that conventional open lateral internal anal sphincterotomy (LIS) for chronic anal fissure (CAF) has been associated with a significant incidence of functional impairment adversely affecting the patient’s quality of life (1,2). This relatively poor functional result is somewhat unpredictable (3), where definitive preoperative imaging by our group has shown relatively poor coronal internal/external anal sphincter (EAS) overlap in some patients with preexistent EAS atrophy, suggesting that in such selected cases, that conventional open LIS may render the distal anal canal relatively unsupported and lead to expected postoperative fecal seepage (4). This approach towards more routine coronal sphincter imaging in patients with topically resistant CAF is not practical, however, except in selected cases where the clinical impression would be that LIS may particularly render continence at risk. This finding has been coupled with significant concerns regarding the use of routine LIS (however, that is performed) in multiparous patients who present with anterior anal fissures where there may be an expectation of coincident EAS damage, as well as in patients with minimally symptomatic Crohn’s-related anal fissures (5).

More recently there has been an improved understanding of the importance of the internal anal sphincter (IAS) in the maintenance of anal continence (6,7), where inherent differences in wave recovery in an IAS-related physiologic function—the rectoanal inhibitory reflex—have been recorded in patients with preexistent EAS atrophy (8). The further importance of the IAS has been shown in observable functional improvement and maintenance of resting anal pressure (a predominantly IAS parameter) when the IAS is preserved in the surgery of high trans-sphincteric anal fistulas (9). Much of this understanding has resulted in the initial widespread use in the management of patients presenting with CAF, of nonoperative topical therapies as well as in selected cases of the utilization of botulinum toxin as a preliminary alternative to sphincterotomy (10,11). Comparative trials have been conducted between these medical alternatives and LIS where in some studies, quite acceptable outcomes are obtained for nonsurgical treatments in terms of fissure healing and quality of life (12,13,14).

The surgical alternatives to formal LIS include fissurectomy (with or without limited sphincterotomy or anoplasty) (15,16), tailored sphincterotomy (17), pressure-directed sphincterotomy (18), pneumatic sphincter dilatation (19), and anal fissurotomy (20). These alternatives to conventional LIS and available data pertaining to their clinical indications in the current decision making for fissure surgery are discussed in this chapter.

The incidence of significant functional impairment following conventional LIS appears to be underestimated (2,21). This is partly because most evaluations do not assess functional quality-of-life issues such as fecal urgency and seepage. Evidence would also suggest that incontinence to flatus in the post-LIS patient, in particular, is underestimated and is more prevalent as a reported symptom only on direct interview as opposed to the retrospective assessment of continence of the patients’ medical files (2). Here, up to 30% of the incontinence initially reported by patients is persistent, particularly when the procedure has been performed in the office under local anesthesia (3,22).

The recent introduction of high-resolution endoluminal imaging of the anal canal has reemphasized the anatomical and clinical importance of the IAS in anal canal anatomy (23). It has become clear that IAS division may be followed by passive incontinence (24); a finding which may be coupled with impaired short- and long-term function following low anterior resection and restorative proctocolectomy in those patients with excessive endoanal manipulation (25). This fact highlights the need for preservation of IAS structure and function (25). Part of the complexity of the response by the IAS to sphincterotomy may be reflected in its known physiology, where continent and incontinent outcomes following partial sphincter division show differential variations in both resting and voluntary squeeze pressure (26) and where minor degrees of incontinence may be present in 28% of patients presenting with a CAF prior to surgery (27).

In the analysis of patients undergoing LIS for CAF, some studies have included the responses to a range of medical and surgical therapies in patients with acute anal fissures without complete characterization of what represents a CAF (28) and in operations where LIS has incorporated additional procedures such as excision of associated hypertrophied anal papillae and sentinel skin tags (29). This literature of CAF management has also been relatively confused with some reports combining nonoperative therapies with a range of different surgeries (30,31). The expanding problem of relatively isolated IAS damage has resulted from an increased use of novel more minimalist techniques in hemorrhoid surgery including Doppler-guided, PPH-stapled, and LigaSure haemorrhoidectomy along with the more widespread availability of endoanal ultrasonography capable of defining the true incidence of postoperative IAS pathology. This knowledge is of considerable clinical relevance given the poor functional results following IAS plication for postoperative fecal seepage deemed primarily to be secondary to IAS damage (32). This problem has recently been somewhat obviated by a range of techniques designed to augment the IAS in postoperative incontinence with varying biomaterials including autologous fat (33), cross-linked collagen (34) and silicone elastomer deployment (35,36,37), technologies designed to bolster the IAS and anal cushion area such as carbon-bead insertion (38) and radio-frequency application (39) and even sacral nerve stimulation (40). These techniques designed to improve IAS function currently have minimal long-term data and interpretation of outcomes must still be viewed with caution when considering the effects of these therapies, since the mechanisms of incontinence and anal closure differ between the post-LIS and post-haemorrhoidectomy cases so far reported (41). The longer-term continence salvaging data relating to these
technologies will have a significant impact on the role of LIS in CAF patients, particularly where currently on clinical grounds, particular cases are deemed to be at relatively higher risk for postoperative incontinence.

Table 18.1 shows some accumulated data concerning outcome following conventional LIS for CAF where data were interpretable for articles referenced in this chapter. Randomized, controlled data have confirmed that such surgical therapy is associated with a very low fissure recurrence rate. In comparison, medically treated patients who have initial success are more likely to experience symptoms over the first year of their assessment and/or to require subsequent surgical therapy over the successive 6 years (42). This result has been accompanied in some series by a high overall satisfaction rate with LIS where over 90% of patients reported that they would again choose the same treatment if the circumstances were the same (43). Such studies are somewhat biased, however, towards single therapies, where variations in reported immediate medical side effects and efficacy will influence initial management decision making. A recent study by Gagliardi and colleagues assessing short- and longer-term medical therapy for CAF with topical high-dose GTN suggests that initially poor responses to such treatment predict for later nonhealing of the fissure and the need for abandonment of the treatment in favour of surgery (28).

Incontinence following LIS is a complex issue due to the sphincterotomy itself rather than showing any linkages to gender, age, other operative procedures combined with sphincterotomy (such as limited haemorrhoidectomy (44)) or previous vaginal delivery history (45

Stay updated, free articles. Join our Telegram channel

Join