Anal fissures
Authors
Elizabeth Breen, MD
Ronald Bleday, MD
INTRODUCTION — Benign anorectal diseases, including fissures, abscesses, fistulas, and hemorrhoids, are common. The prevalence of specific disorders is difficult to estimate since almost any anorectal discomfort is often attributed to symptomatic hemorrhoids. However, the prevalence in the general population is probably much higher than seen in clinical practice since the majority of patients with symptoms referable to the anorectum do not seek medical attention. In one telephone survey involving 102 randomly selected individuals in the general population who were between the ages of 21 and 65, approximately 9 percent had been previously treated for hemorrhoids, and 20 percent had ongoing symptoms referable to the anorectum, the majority of whom had not consulted a physician [1].
The diagnosis and treatment of anal fissures will be reviewed here. Other anorectal disorders, such as anal abscesses and fistulas, anal pruritus, and hemorrhoids are discussed separately. (See "Anal abscesses and fistulas" and "Approach to the patient with anal pruritus" and "Overview of hemorrhoids" and "Treatment of hemorrhoids".)
This topic is also discussed in a guideline issued by the American Gastroenterological Association. The American Gastroenterological Association (AGA) guideline for the diagnosis and care of patients with anal fissure [2], as well as other AGA guidelines, can be accessed through the AGA web site at http://www.gastro.org/practice/medical-position-statements.
DEFINITION AND PATHOGENESIS — An anal fissure is a tear in the lining of the anal canal distal to the dentate line, which most commonly occurs in the posterior midline. The majority of anal fissures are caused by local trauma to the anal canal, such as after passage of hard stool. Anal fissures can also be seen in patients with Crohn's disease, tuberculosis, and leukemia. (See "Perianal complications of Crohn's disease", section on 'Anal fissures'.)
Once the tear occurs, it begins a cycle leading to repeated injury. The exposed internal sphincter muscle beneath the tear goes into spasm. In addition to causing severe pain, the spasm pulls the edges of the fissure apart, which impairs healing of the wound. The spasm also leads to further tearing of the mucosa with the passage of subsequent bowel movements.
In some patients, this cycle leads to the development of a chronic anal fissure. It has been proposed that ischemia may contribute to the development of this problem. Blood flow in the anoderm at the posterior midline, the site of most fissures, is less than one-half that in other quadrants in the anal canal [3,4]. Furthermore, the rate of perfusion is inversely related to anal pressure and, in one study, patients with chronic anal fissure had higher anal pressures than those with fecal incontinence, hemorrhoids, or other colorectal disorders, or controls [3]. The demonstration of reduced blood flow provided the rationale for the use of topical nitroglycerin in the treatment of this disorder (see 'Topical nitroglycerin' below).
The elevation in anal pressure in patients with chronic anal fissure may result from increased tone of the internal anal sphincter, which can be demonstrated manometrically [5-7]. In one study, for example, manometry was performed in 12 patients with chronic anal fissure and in 12 controls [5]. The mean average resting pressure of the internal sphincter was significantly higher in patients with a chronic anal fissure (120 versus 83 mmHg).
Factors other than reduced blood flow also may contribute to the posterior predilection for anal fissures. Elevated internal sphincter pressures are not confined to the site of the fissure; in one study, they were highest on the distal anterior surface, which may favor posterior mucosal tearing during defecation [5]. Another hypothesis is the elliptical arrangement of anal sphincter fibers, which lends less support to the posterior aspect of the anal canal.
DIAGNOSIS — Anal fissures can usually be diagnosed from the history. Affected patients describe a tearing pain with the passage of bowel movements. The passage of stool may be accompanied by bright rectal bleeding, usually limited to a small amount on the toilet paper or on the surface of stool. Some patients complain of an itch or perianal skin irritation.
The best way to diagnose an anal fissure during physical examination is to spread the buttocks apart gently, looking carefully in the posterior midline. Patients are often too uncomfortable to tolerate a digital rectal examination or anoscopy. The second most frequent location is the anterior midline, which should also be inspected [8]. Eccentrically located fissures occur, but are most often associated with atypical etiologies.
An acute fissure appears as a fresh laceration; a chronic fissure has raised edges exposing the white, horizontally oriented fibers of the internal anal sphincter at its base (picture 1). Chronic fissures are often accompanied by external skin tags distally, and hypertrophied anal papillae at their proximal extent. Recurrent or nonhealing fissures despite medical therapy, and fissures occurring outside of the posterior or anterior midline, should raise concern for underlying diseases, particularly Crohn's disease. (See "Perianal complications of Crohn's disease".)
Patients with rectal bleeding should undergo endoscopy. A sigmoidoscopy may be reasonable in patients younger than 50 who have no family history of colon cancer; in other patients, a full colonoscopy should be performed. Patients who have atypical fissures or other clinical features raising suspicion for underlying Crohn's disease should have a full colonoscopy and imaging of the small bowel. (See "Clinical manifestations, diagnosis and prognosis of Crohn's disease in adults", section on 'Small bowel disease'.)
TREATMENT — The goals of therapy are to break the cycle of sphincter spasm and tearing of the anal mucosa, and to promote healing of the fissure. Medical therapy is successful in the majority of patients [9,10], with surgery being reserved for refractory cases (algorithm 1).
Medical therapy — Medical therapy has traditionally consisted of three components: relaxation of the internal sphincter, institution and maintenance of atraumatic passage of stool, and pain relief. In many cases, these goals can be accomplished with fiber therapy to keep the stools soft and formed, and warm sitz baths following bowel movements to relax the sphincter [11]. Topical anesthetic creams to soothe the inflamed anoderm are often prescribed, but have not been shown to be more effective than fiber and sitz baths alone [12]. (See "Management of chronic constipation in adults", section on 'Dietary changes and bulk forming laxatives'.)
Topical nitroglycerin — The observation that the posterior commissure of the internal anal sphincter is less perfused than the other sections led to the concept that ischemia could be contributing to the persistence of anal fissures [3,4]. Topical nitroglycerin increases local blood flow and reduces pressure in the internal anal sphincter, which may further facilitate healing. It is applied as a 0.2 to 0.4 percent ointment. In 2011, the US Food and Drug Administration approved a 0.4 percent nitroglycerin ointment (Rectiv, ProStrakan Group). Prior to that, the commercially available nitroglycerin ointments in the United States were 2 percent, a concentration that may not be well tolerated [13]. A 0.2 percent concentration can be custom-made by a pharmacist.
Topical nitroglycerin has been evaluated in multiple series and in controlled trials that have generally shown a beneficial effect compared with placebo, although discordant data have been reported [14-21]. In an illustrative study, 80 consecutive patients with chronic anal fissures (defined as symptoms of anal fissure for more than six weeks with fibrosis at the base of the fissure) were randomly assigned to receive treatment with topical glyceryl trinitrate (one-half of a pea-sized lump of a 0.2 percent ointment applied twice daily) or placebo [15]. After eight weeks, healing was observed significantly more often in patients receiving glyceryl trinitrate (68 versus 8 percent). The median time to healing was six weeks (range four to eight weeks). Healing was accompanied by improvement in pain, and a reduction in the maximum anal resting pressure.
Most patients had a lasting response to therapy. Three patients relapsed after one, two, and four months. In a separate report from the same authors, long-term follow-up (median 28 months) of 41 patients who had received treatment with glyceryl trinitrate revealed that 11 (27 percent) had a symptomatic relapse, eight of whom were treated nonsurgically (six with additional treatment with glyceryl trinitrate, and two spontaneously); the remaining three patients were treated by sphincterotomy [22].
The major side effect was headache, which occurred 10 to 15 minutes after application and lasted no more than 30 minutes in most patients. Headaches occurred most commonly after two weeks of therapy, and decreased thereafter [23]. As with other forms of nitrate therapy, patients taking sildenafil (Viagra) are at increased risk for hypotension. Nitrates should not be prescribed within 24 hours of taking this medication (see "Treatment of male sexual dysfunction" and "Patient information: Anal fissure (Beyond the Basics)").
Treatment with topical nitroglycerin may also be beneficial in patients with acute anal fissure. This was illustrated in a study of 35 patients with anal fissure (22 acute and 13 chronic) who were randomized to topical glyceryl trinitrate or topical lidocaine [17]. Patients with acute anal fissures receiving glyceryl trinitrate were far more likely to heal by 14 days (92 versus 0 percent).
However, as noted above, not all trials have shown beneficial effects. As an example, a trial involving 132 patients found no significant difference between healing rates in those receiving placebo or nitroglycerin (49 versus 52 percent) [18]. Furthermore, orthostatic hypotension developed in 6 percent of patients receiving nitroglycerin. The findings led the authors to discourage the use of nitroglycerin. A concern with this study is that is unclear why patients in the placebo arm experienced a spontaneous healing rate that was much higher than observed in other studies.
Another study examined variables that were associated with failure to respond to topical glyceryl trinitrate in a group of 64 patients with chronic anal fissures [24]. Initial healing was observed in 26 patients (41 percent), but they experienced a recurrence during a mean follow-up of 16 months. Fissures were significantly less likely to heal, more likely to recur, and more likely to remain unhealed in the long-term in patients who had a fissure in association with a sentinel pile (present in 30 percent of the cohort) and those whose fissures had been present for more than six months.
Botulinum toxin — Botulinum toxin is a potent inhibitor of the release of acetylcholine from nerve endings and has been used successfully for decades to treat certain spastic disorders of skeletal muscle such as blepharospasm and torticollis, and more recently, for achalasia. Injection of botulinum toxin into the anal sphincter can improve healing in patients with chronic anal fissure. In one study, for example, 30 consecutive patients with chronic anal fissure were randomized to intrasphincteric botulinum toxin type A or saline injection [25]. Injection was accomplished by palpation of the internal anal sphincter and administration of a total volume of 0.4 mL (in two equal doses for a total of 20 units of botulinum toxin) via a 27-gauge needle close to the fissure on each side. No sedation or local anesthesia was used. After two months, significantly more patients who had received botulinum toxin had healed (73 versus 13 percent). Four patients who had received botulinum toxin required a second injection (25 units), and all subsequently healed. No relapses occurred during an average follow-up of 16 months. One patient developed temporary flatus incontinence. Temporary fecal incontinence after therapy has been reported in other series [26,27].
As suggested in the above study [25], repeated therapy with botulinum toxin may be beneficial for patients who relapse or do not respond to initial treatment. This was underscored in a series that included 50 patients, 20 of whom had relapsed following initial treatment, and 30 of whom had failed initial treatment [27]. The 20 patients who relapsed were retreated with the same dose as initial treatment (5 units), while the 30 in whom treatment had failed were retreated with a higher dose (10 units). Nineteen of the 20 patients (95 percent) treated with 5 units were pain free within one week, and healing was observed in 70 percent by three months. In the group treated with 10 units, 22 of 30 (73 percent) became pain free by one week, and 19 (63 percent) showed healing three months after injection. Transient mild incontinence was observed in two patients (7 percent). Initial treatment failures may have been due to a relatively low dose of botulinum toxin compared with other reports [25]. However, pathologic causes of recurrent or unhealing fissures (such as inflammatory bowel disease) should be considered in these patients.
The long-term outcome of patients treated with botulinum toxin has not been well described, but recurrence appears to be common. One report with the longest follow-up included 57 patients who had completely healed six months after injection and were followed for 42 months [28]. A recurrent fissure was observed in 22 patients (42 percent). Compared with patients who achieved long-term healing, those with recurrence were significantly more likely to have had anterior fissures (45 versus 6 percent), had a longer duration of disease, needed reinjection (59 versus 26 percent), required a higher total dose to achieve healing, and had not achieved as great a percentage decrease of maximum anal squeeze pressure after injection.
Topical nitroglycerin versus botulinum toxin — At least three randomized controlled trials have compared topical nitroglycerin with botulinum toxin A [29-31]. Two of them were performed by the same group [29,31]
•The largest trial (involving 100 patients) found significantly higher rates of healing at two months in patients randomized to botulinum toxin A (92 versus 70 percent) [31].
•A similarly higher rate of healing with botulinum toxin A at two month (96 versus 60 percent) was observed in a second trial involving 50 patients [29].
Side-effects (mainly headache) were more frequent in the nitroglycerin group. However, mild (mainly transient) incontinence to flatus was observed more frequently in the botulinum toxin group. Patients with side-effects (or an incomplete response) to one treatment often had success when crossed to the other.
A reasonable conclusion is that both treatments are acceptable options for first-line therapy; one or the other option can be used in patients who do not respond, or who are intolerant to treatment. Botulinum toxin appears to be somewhat more effective (at least with short-term follow-up) but has a higher frequency of mild incontinence. Because botulinum toxin is more invasive and is associated with a greater risk of mild incontinence, we generally reserve it for patients who have not responded to topical nitroglycerin (see 'Recommendation' below).
Topical nitroglycerin plus botulinum toxin — A possible additive effect of topical nitroglycerin plus botulinum toxin injection was evaluated in a controlled trial involving 30 patients who did not respond to topical nitroglycerin [32]. Patients were randomly assigned to botulinum toxin injection with or without topical nitroglycerin. The healing rate at six weeks was significantly higher in those who received combination therapy (66 versus 20 percent). No significant differences were seen at 8 and 12 weeks.
Oral nifedipine — The ability of the calcium channel blocker nifedipine to reduce resting internal anal sphincter pressure prompted its use for the treatment of patients with chronic anal fissures. In an open label trial, 15 patients were treated with a slow-release nifedipine (Adalat, Bayer pharmaceuticals, 20 mg twice daily) for eight weeks [33]. Treatment was associated with an initial reduction in maximum anal resting pressure and pain scores. Complete healing was observed in nine patients (60 percent) after eight weeks, while three additional patients were asymptomatic. Ten patients experienced flushing, one developed mild ankle edema, and four had mild headaches. This study has been criticized because of the short duration of follow-up, frequent side effects, relatively poor efficacy of nifedipine compared with other approaches, and lack of a control group [34].
Topical nifedipine versus topical nitroglycerin — The efficacy of topical nifedipine was compared to topical nitroglycerin in a randomized controlled trial involving 52 patients [35]. The healing rate was higher with nifedipine (89 versus 58 percent) and treatment side effects were less frequent (5 versus 40 percent). Reductions in pain scores were significantly lower in both groups. Recurrence developed in a similar proportion of patients (42 and 31 percent, respectively) after a mean of 183 and 124 weeks, respectively.
Oral diltiazem — The efficacy of topical versus oral diltiazem was evaluated in a controlled trial involving 50 patients [36]. Complete fissure healing by eight weeks was observed in nine patients (38 percent) receiving oral diltiazem compared with 15 patients (65 percent) receiving topical treatment. Side effects were more common in those receiving oral therapy.
Topical diltiazem or bethanechol — A pilot study involving a total of 30 patients suggested that topical diltiazem (2 percent) or a topical bethanechol (0.1 percent) gel (neither of which are commercially available in the United States) applied three times daily were effective in healing anal fissures in 67 and 60 percent of patients, respectively [37]. The authors note that these results were comparable to topical nitroglycerin but without headache or other significant side effects.
Similar results with topical diltiazem were observed in a separate study of 71 patients; healing was observed in 75 percent after two to three months of treatment [38]. Twenty-seven of the 41 responding patients (66 percent) remained symptom free during a median of 32 weeks of follow-up. Six of seven patients with recurrent symptoms were successfully treated with a second course. No side effects were reported. In another report, topical diltiazem was associated with healing in 19 of 39 patients who had failed to heal with topical nitroglycerin [39].
Surgical therapy — Surgery should be reserved for patients in whom anal fissures fail to heal despite adequate medical therapy. The goal of surgical therapy is to relax the internal anal sphincter, which is most often accomplished by a lateral internal sphincterotomy. This procedure involves division of the internal anal sphincter from its distal most end for a distance equal to that of the fissure, or up to the dentate line. The sphincter can be divided in a closed or open fashion, depending upon the preference of the surgeon. The sphincterotomy heals best if it is performed in the right or left lateral position, and not in the posterior or anterior midline. The fissure itself does not require surgical therapy (eg, fissurectomy) unless it has an atypical appearance and a biopsy is warranted.
Lateral sphincterotomy is successful in approximately 95 percent of patients [40-42]. In one series of 350 patients who underwent open or closed lateral internal anal sphincterotomy for acute or chronic anal fissure, only 21 patients (6 percent), failed to heal or developed a recurrence [41]. Five of these patients were eventually diagnosed with Crohn's disease. Postoperative infections developed in eight patients (2 percent), four of which were associated with fistulas. Incontinence for flatus or stool, which was usually transient, developed in 17 percent. The results were similar for the open and closed methods.
Lateral sphincterotomy versus topical nitroglycerin — At least two controlled trials have compared the efficacy of lateral sphincterotomy versus topical nitroglycerin therapy [43,44]. One trial involved 65 patients who were randomly assigned to one or the other modality [43]. Healing at eight weeks was observed significantly more often in those randomized to surgery (97 versus 61 percent). Twelve patients who received topic nitroglycerin eventually underwent lateral sphincterotomy. Poor tolerance and compliance were risk factors for failure to heal with topical nitroglycerin.
A second study included 54 patients who were followed for up to two years after treatment [44]. In the nitroglycerin group, 18 patients (67 percent) healed by five weeks and 24 (89 percent) by ten weeks. Minor side effects were experienced by eight patients (30 percent). In the surgical group, 26 (96 percent) healed by five weeks and 100 percent by ten weeks. Minor fecal incontinence was experienced by 44 percent, which remained in 15 percent after 24 months follow-up. The percentage of patients healed at the five week point was significantly higher in the surgical group. The author concluded that nitroglycerin should be considered as the first choice with surgery reserved for patients in whom treatment is unsuccessful.
Lateral sphincterotomy versus botulinum toxin injection — At least one controlled trial has directly compared lateral sphincterotomy with botulinum toxin injection [45]. The authors concluded that the proportion of patient with healing after botulinum toxin A injection was high overall (albeit lower than sphincterotomy at one year), but the rate of healing was slower than with lateral sphincterotomy. However, botulinum toxin injection was associated with fewer complications and faster recovery.
The study included 111 patients with chronic anal fissures who were randomly assigned to treatment with botulinum toxin or to lateral sphincterotomy [45]. Patients were assessed at regular intervals for one year. Complete healing was observed in 64 percent of patients in the botulinum group at two months. Ten nonresponding patients underwent a second injection yielding an overall healing rate of 87 percent at six months. The healing rate was significantly higher by two months in the sphincterotomy group (98 versus 64 percent), but was similar to the botulinum group at six months (96 versus 87 percent). After one year, there were seven recurrences in the botulinum group resulting in an overall success rate of 75 percent; there were no recurrences after six months in the sphincterotomy group (two patients had recurrences prior to six months). Complication rates were significantly higher in the sphincterotomy group (including eight cases of fecal incontinence versus none in the botulinum group). Full return to normal activities was also more rapid in the botulinum group.
Lateral sphincterotomy versus oral nifedipine — A controlled trial randomly assigned 132 patients with a chronic anal fissure to either a lateral sphincterotomy, a tailored sphincterotomy, or oral nifedipine [46]. The surgical approaches were associated with significantly better fissure healing rates at 16 weeks and less recurrence. Compliance with nifedipine was poor due to side-effects and slow healing. There was no difference in continence between the three treatment groups.
Risk of incontinence — As noted above, a concern with surgery for anal fissures is the risk of fecal incontinence. Fecal incontinence can be characterized as either minor (defined as inadvertent escape of flatus or partial soiling of undergarments with liquid stool) or major (involuntary excretion of feces). (See "Fecal incontinence in adults".) Most series of sphincterotomy for anal fissures have described only minor incontinence. The risk has varied among reports from as low as 0 to as high as 24 percent [47]. In most reports the risk has been less than 10 percent.
However, it is possible that the rates reported in many studies may be underestimates, a point that was illustrated in a survey study involving 298 patients who underwent sphincterotomy [48]. Significantly more patients reported minor incontinence than was recorded in the medical record. Temporary incontinence was reported by 31 percent of patients while 30 percent described persistent incontinence to gas. No patients described major incontinence. Fecal incontinence was more likely in women who had two or more previous vaginal deliveries.
Another survey study included 487 patients who had undergone lateral internal sphincterotomy [42]. Fissures had healed by a median of three weeks after surgery in 96 percent of patients and were recurrent in only 8 percent. Some degree of fecal incontinence was reported in 45 percent of patients at some time in the postoperative period and was more likely in women (53 versus 33 percent). Incontinence to flatus, mild soiling, and gross incontinence occurred in 31, 39, and 23 percent of patients respectively. However, by the time of the survey (an average of five years after the procedure), only six percent reported incontinence to flatus, while eight percent had minor fecal soiling, and one percent experienced loss of solid stool. Only three percent of patients reported that incontinence had ever affected their quality of life.
Considered together, these data suggest that 30 to 45 percent of patients will experience minor incontinence following lateral sphincterotomy, which persists in 6 to 30 percent of patients after long-term follow-up. This can be compared to a background rate of fecal incontinence in the general population of approximately 2 percent [49]. The risk is increased in women, particularly those who have had previous vaginal deliveries. The minor incontinence generally does not have a major impact on quality of life. Major incontinence is rare.
Dilation — A Lord's or four finger dilatation in the operating room has been used for the treatment of anal fissures [50]. Although this treatment can improve the spasm in the internal anal sphincter, it is associated with a high incidence of sphincter tears and fecal incontinence.
Pneumatic balloon dilation has also been performed for treatment of chronic anal fissures [51]. Experience is limited and it has not been compared directly with other approaches.
Recommendation — An optimal strategy for the management of anal fissures has not been established. Our current approach based upon the published literature and clinical experience is illustrated in the following algorithm (algorithm 1).
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
•Beyond the Basics topics (see "Patient information: Anal fissure (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
•An anal fissure is a tear in the lining of the anal canal distal to the dentate line, which most commonly occurs in the posterior midline. The majority of anal fissures are caused by local trauma to the anal canal, such as after passage of hard stool. Once the tear occurs, it begins a cycle leading to repeated injury. The exposed internal sphincter muscle beneath the tear goes into spasm. In addition to causing severe pain, the spasm pulls the edges of the fissure apart, which impairs healing of the wound. The spasm also leads to further tearing of the mucosa with the passage of subsequent bowel movements. In some patients, this cycle leads to the development of a chronic anal fissure. (See 'Definition and pathogenesis' above.)
•Anal fissures can usually be diagnosed from the history. Affected patients describe a tearing pain with the passage of bowel movements. The passage of stool may be accompanied by bright rectal bleeding, usually limited to a small amount on the toilet paper or on the surface of stool. Some patients complain of an itch or perianal skin irritation. The best way to diagnose an anal fissure during physical examination is to spread the buttocks apart gently, looking carefully in the posterior midline. Patients are often too uncomfortable to tolerate a digital rectal examination or anoscopy. The second most frequent location is the anterior midline, which should also be inspected. Eccentrically located fissures occur, but are most often associated with atypical etiologies. (See 'Diagnosis' above.)
•The goals of therapy are to break the cycle of sphincter spasm and tearing of the anal mucosa, and to promote healing of the fissure. An optimal strategy for the management of anal fissures has not been established. Our current approach based upon the published literature and clinical experience is illustrated in the following algorithm (algorithm 1). (See 'Treatment' above.)
•Medical therapy is successful in the majority of patients, with surgery being reserved for refractory cases. In many cases, these goals can be accomplished with fiber therapy to keep the stools soft and formed, and warm sitz baths following bowel movements to relax the sphincter. Options for patients who fail to respond to these measures include topical nitroglycerin and botulinum toxin injection. (See 'Medical therapy' above.)
•Topical nitroglycerin increases local blood flow and reduces pressure in the internal anal sphincter, which may further facilitate healing. It is applied as a 0.2 to 0.4 percent ointment. Trials have generally shown a beneficial effect of nitroglycerin compared with placebo. The most common side effect is headache. (See 'Topical nitroglycerin' above.)
•Botulinum toxin is a potent inhibitor of the release of acetylcholine from nerve endings. Injection of botulinum toxin into the anal sphincter can improve healing in patients with chronic anal fissure and repeated therapy with botulinum toxin may be beneficial for patients who relapse or do not respond to initial treatment. The long-term outcome of patients treated with botulinum toxin has not been well described, but recurrence appears to be common. (See 'Botulinum toxin' above.)
•Studies suggest that either topical nitroglycerin or botulinum toxin injection is a reasonable treatment for patients who require therapy beyond fiber and sitz baths. In addition, patients can be switched to the other treatment if do not respond or are intolerant to treatment. Botulinum toxin appears to be somewhat more effective (at least with short-term follow-up) but has a higher frequency of mild incontinence. Because botulinum toxin is more invasive and is associated with a greater risk of mild incontinence, we generally reserve it for patients who have not responded to topical nitroglycerin. (See 'Topical nitroglycerin versus botulinum toxin' above.)
•Surgery should be reserved for patients in whom anal fissures fail to heal despite adequate medical therapy. The goal of surgical therapy is to relax the internal anal sphincter, which is most often accomplished by a lateral internal sphincterotomy. Lateral sphincterotomy is successful in approximately 95 percent of patients. However, 30 to 45 percent of patients will experience minor incontinence following lateral sphincterotomy, which persists in 6 to 30 percent of patients after long-term follow-up. The risk is increased in women, particularly those who have had previous vaginal deliveries. The minor incontinence generally does not have a major impact on quality of life and major incontinence is rare. (See 'Surgical therapy' above.)

I wish that I could find European notes on Standardized Anal Dilation instead of this continual reference to Lord's dilation! If anyone knows of any site with information, do post it!

kinda disheartening for me for the idea of botox.
like a 50% chance of it helping.
Thanks for posting this Sav,
it's more thorough than some of the stuff I've read.
-Tanya

I agree about the Botox. Just don't want to do something that might aggravate other things, like hemmies.
Got dilators in the post today. Haven't opened the box yet...