Anal Sphincter Complex Research Articles

Ultrasonography Accuracy for Perianal Fistula Anatomy

Background Endorectal ultrasonography is a diagnostic modality for evaluation of perianal pathologies and suitable surgical planning, especially in perianal fistula, due to its close relation to the anal sphincter complex. Detection of anatomical location of fistula tract and abscess is critical to select the best procedure. Objectives This study tries to demonstrate the accuracy of endorectal ultrasonography in mixed group of patients in diagnosing perianal fistula during two years, retrospectively. Patients and Methods After Ethics Committee approval, all endorectal ultrasonography reports of all patients with perianal fistula referred to Shiraz Endorectal Ultrasonography Clinic of Shiraz colorectal research center between 2010 and 2012 were gathered. All endorectal ultrasonographies in this center was perform by a colorectal surgeon with BK Medical Class I type B Ultrasonography scanner with 12 MHz probe. Results Finally, 183 cases of perianal fistula were enrolled in the study. Operation notes were evaluated and the type of fistula was compared with ultrasound findings. This study showed that endorectal ultrasonography has adequate accuracy with 97.92% sensitivity and acceptable 89.53% specificity in diagnosis of perianal fistula. Compared with other reports, it seems that endorectal ultrasonography is an acceptable diagnostic tool for detecting perianal fistula compared with other diagnostic modalities. Conclusions Endoanal sonography would be one of the high sensitive modalities for evaluation of perianal fistula. Detection of anatomy of fistula helps surgeon to choose best method for surgery.

Is a new high-resolution probe better than the standard probe for 3D anal sphincter and levator ani imaging?

The aim of our study was to determine the accuracy of a new three-dimensional (3D) endoluminal ultrasound probe in assessing the levator ani muscle and anal sphincter complex. A total of 85 patients who had undergone concurrent 3D endovaginal (EVUS) and 3D endoanal (EAUS) ultrasound with both the standard BK 2052 probe and the new high-definition BK 8838 probes were included. For EVUS volumes, the levator ani deficiency (LAD) scores were calculated for each probe. For the EAUS volumes, any defects in the external anal sphincter (EAS) and the internal anal sphincter (IAS) visualized with each probe were recorded. The 3D volumes were evaluated in a blinded fashion. Appropriate statistics were utilized to assess absolute agreements between each pair of imaging modalities. The mean age of the patient population was 59 years (SD ± 10.76), the mean body mass index (BMI) was 28.36 (SD ± 5.99), and the median parity was 2 (range 1, 7). In all, 93% of the patients were Caucasian, 31% had stage 0 or 1 prolapse, while 59% had stage 2 prolapse. The mean total LAD score obtained on EVUS with the standard and the new probes were 11.49 (SD ± 4.94) and 11.53 (SD ± 5.01), respectively, p = 0.3778. Among the 53 patients who had EAUS with both probes, exact agreement for visualization of EAS and IAS for the standard and the new probes was 83% and 98%, respectively. Both transducers can be used for endovaginal imaging of the levator ani muscles interchangeably. Both transducers can be used for endoanal imaging of anal sphincter complex interchangeably.

Functional outcome after anal sphincter injury and treatment with mesenchymal stem cells.

This research demonstrates the regenerative effects of mesenchymal stem cells (MSCs) on the injured anal sphincter by comparing anal sphincter pressures following intramuscular and serial intravascular MSC infusion in a rat model of anal sphincter injury. Fifty rats were divided into injury (n = 35) and no injury (NI; n = 15) groups. Each group was further divided into i.m., serial i.v., or no-treatment (n = 5) groups and followed for 5 weeks. The injury consisted of an excision of 25% of the anal sphincter complex. Twenty-four hours after injury, 5 × 10(5) green fluorescent protein-labeled MSCs in 0.2 ml of phosphate-buffered saline (PBS) or PBS alone (sham) were injected into the anal sphincter for i.m. treatment; i.v. and sham i.v. treatments were delivered daily for 6 consecutive days via the tail vein. Anal pressures were recorded before injury and 10 days and 5 weeks after treatment. Ten days after i.m. MSC treatment, resting and peak pressures were significantly increased compared with those in sham i.m. treatment (p < .001). When compared with the NI group, the injury groups had anal pressures that were not significantly different 5 weeks after i.m./i.v. treatment. Both resting and peak pressures were also significantly increased after i.m./i.v. MSC treatment compared with treatment with PBS (p < .001), suggesting recovery. Statistical analysis was done using paired t test with Bonferroni correction. Marked decrease in fibrosis and scar tissue was seen in both MSC-treated groups. Both i.m. and i.v. MSC treatment after injury caused an increase in anal pressures sustained at 5 weeks, although fewer cells were injected i.m. The MSC-treated groups showed less scarring than the PBS-treated groups, with the i.v. infusion group showing the least scarring.

Experience with Proctectomy to Manage Combat Casualties Sustaining Catastrophic Perineal Blast Injury Complicated by Invasive Mucor Soft-Tissue Infections

Catastrophic pelviperineal injuries have become more commonplace on the modern battlefield as a result of dismounted blast mechanism and the survival benefits afforded by far-forward resuscitation and surgery. Inherent in the survival of casualties with such devastating injuries is both the risk for invasive infections and the need for complex reconstruction. We report a series of two combat casualties sustaining the constellation of catastrophic pelviperineal blast injury, anal sphincter complex destruction, complicated by invasive fungal infection managed with completion proctectomy. Our experience, although lacking numbers to qualify as high-level evidence to guide care, will assist future surgeons' care for similar patients.

Late effects of pelvic radiation for rectal cancer and implications for survivorship

Improved treatment for colorectal cancer with better survival rates has heightened awareness of the potential late toxicities of pelvic radiation. Colorectal cancer (CRC) survivors experience inferior physical and mental quality of life (Denlinger and Barsevick, 2009 [3]). As a growing population of CRC survivors live long enough to experience normal tissue adverse effects induced or exacerbated from pelvic radiation, survivorship plans that address subsequent gastrointestinal and sexual dysfunctions are beginning to emerge. Early identification and referral for treatment interventions is important for reducing late toxicity; however, prevention is still the best practice, with clinicians optimizing patient- and treatment-specific factors. Practices that reduce irradiation of critical pelvic structures include treating locally advanced patients preoperatively with multiple beam techniques that minimize the dose delivered to the small bowel, avoiding inclusion of the anal sphincter complex for higher tumors, and maximizing testicular shielding. For younger women of childbearing age, consideration of fertility-preservation options at diagnosis is essential. In this review, we will describe the data relevant to radiation-induced late effects for rectal cancer that focus on gastrointestinal and sexual sequelae. We will also explore some potential prevention and management options for long-term treatment-related morbidity.

New Treatments for Fecal Incontinence: Update for the Gastroenterologist

Fecal incontinence is one of the most emotionally devastating of all nonfatal conditions. Many patients do not respond satisfactorily to conservative measures, and there is a need for new and effective strategies when medical therapy fails. The development of sacral nerve stimulation and other forms of neuromodulation and the injection of biologically compatible substances into the anal sphincter complex have brought renewed enthusiasm for using these novel treatments in this underserved population. Because injectable bulking agents such as dextranomer in stabilized hyaluronic acid can be administered in an outpatient setting, this procedure is being marketed to both gastroenterologists and surgeons. This article reviews both sacral nerve stimulation and dextranomer bulking agents and compares their strengths and potential limitations in patients with fecal incontinence.

Long-term Results of Mucosal Advancement Flap Combined With Platelet-rich Plasma for High Cryptoglandular Perianal Fistulas

The long-term closure rate of high perianal fistulas after surgical treatment remains disappointing. The goal of this study was to improve the long-term closure rate of high cryptoglandular perianal fistulas combining mucosal advancement flap with platelet-rich plasma. This study was retrospective in design. This study was conducted at 2 secondary and 1 tertiary referral hospitals. Patients presenting with high cryptoglandular perianal fistulas involving the middle/upper third of the anal sphincter complex were included. A staged surgical treatment was performed; After seton placement, a mucosal advancement flap was combined with platelet-rich plasma. Recurrence was the main outcome. Incontinence was the secondary outcome. We operated on 25 patients between 2006 and 2012. Thirteen (52%) patients had previous fistula surgery. The median follow-up period was 27 months. One patient (4.0%) was lost to follow-up after 4 months. Freedom from recurrence at 2 years was 0.83 (95% CI, 0.62-0.93). Two of the 4 patients with a recurrence (8%) had a repeated treatment and healed. One patient (4.0%) refused another treatment, but agreed to stay in follow-up. One patient (4.0%) requested a colostomy, resulting in closure of the fistula. Complications occurred in 1 patient (4.0%). Incontinence numbers were low with a median Vaizey score of 3.0 out of a maximum of 24. The study was limited by its retrospective design, lack of preoperative incontinence data, selection bias, and phone interview follow-up. The long-term outcome results of patients with primary and recurrent high cryptoglandular perianal fistulas treated with a seton followed by mucosal advancement flap and platelet-rich plasma show low recurrence, complication, and incontinence rates. Therefore, this technique seems to be a valid option as treatment. Larger and preferably randomized controlled studies are needed to further explore this surgical technique.

Fecal Incontinence: The Role of the Urologist

Fecal incontinence is the involuntary loss of solid or liquid stool. While the true prevalence of fecal incontinence is difficult to discern, it is estimated that almost 9 % of non-institutionalized women in the US experience this condition. Disorders leading to fecal urgency alone are usually related to rectal storage abnormalities while incontinence is often a result of anatomic or neurologic disruption of the anal sphincter complex. Many risk factors exist for fecal incontinence and include female sex, increasing age, higher body mass index (BMI), limited physical activity, smoking, presence of neuropsychiatric conditions, higher vaginal parity and history of obstetrical trauma, presence of chronic diarrhea and irritable bowel syndrome, or history of rectal surgery, prostatectomy and radiation. Evaluation of fecal incontinence involves a careful patient history and focused physical exam. Diagnostic tests include endorectal ultrasonography, anal manometry, anal sphincter electromyography, and defecography. Treatment strategies include behavioral, medical and surgical therapies as well as neuromodulation. Treatment is based on the presumed etiology of the condition and a multi-modal approach is often necessary to achieve the maximum benefit for patients.

Anatomical disruption and length-tension dysfunction of anal sphincter complex muscles in women with fecal incontinence.

Anal sphincter complex muscles, the internal anal sphincter, external anal sphincter, and puborectalis muscles, play an important role in the anal continence mechanism. Patients with symptoms of fecal incontinence have weak anal sphincter complex muscles; however, their length-tension properties and relationship to anatomical disruption have never been studied. This study aimed to assess the anatomy of the anal sphincter complex muscles with the use of a 3-dimensional ultrasound imaging system and to determine the relationship between the anatomical defects and the length-tension property of external anal sphincter and puborectalis muscles in women with incontinence symptoms and in control subjects. Severity of anal sphincter muscle damage was determined by static and dynamic 3-dimensional ultrasound imaging. The length-tension property was determined by anal and vaginal pressure with the use of custom-designed probes. Forty-four asymptomatic controls and 24 incontinent patients participated in this study. The anatomical defects and length-tension dysfunction of anal sphincter complex muscles in patients with fecal incontinence were evaluated. The prevalence of injury to sphincter muscles is significantly greater in the incontinent patients than in the controls. Eighty-five percent of patients but only 9% controls reveal damage to ≥2 of the 3 muscles of the anal sphincter complex. Anal and vaginal squeeze pressures increased with the increase in the probe size (length-tension curve) in the majority of controls. In patients, the increase in anal and vaginal squeeze pressures was either significantly smaller than in controls or it decreased with the increasing probe size (abnormal length-tension). We studied patients with severe symptoms. Whether our findings are applicable to patients with mild to moderate symptoms remains to be determined. The length-tension property of the external anal sphincter and puborectalis muscles is significantly impaired in incontinent patients. Our findings have therapeutic implications for the treatment of anal incontinence.

Postpartum translabial 2D and 3D ultrasound measurements of the anal sphincter complex in primiparous women delivering by vaginal birth versus Cesarean delivery

Consensus on normal translabial ultrasound (TL-US) anal sphincter complex measurements for postpartum women is lacking. We aimed to evaluate normative measurements in 2D and 3D TL-US for the anal sphincter complex (ASC) at 6months postpartum and compare these measurements in women who had a vaginal birth (VB) and in those who had a Cesarean delivery (CD). A large, prospective cohort of primiparous women underwent 2D and 3D TL-US 6months after their first delivery. For normative sphincter measurements, we excluded women with third- or fourth-degree lacerations or with sphincter interruption on TL-US. Measurements included the sphincter thickness at the 3, 6, 9, and 12 o'clock positions of the external anal sphincter (EAS) and the internal anal sphincter (IAS) at proximal, mid, and distal levels. We also measured the mean coronal diameter of the pubovisceralis muscle (PVM). 696 women consented to participate, and 433 women presented for ultrasound imaging 6months later. Women who sustained a third- or fourth-degree laceration had significantly thicker EAS measurements at 12 o'clock. Sphincter asymmetry was common (69%), but was not related to mode of delivery. Only IAS measurements at the proximal and distal 12 o'clock position were significantly thicker for CD patients. There were no significant differences in the EAS or PVM measurements between VB and CD women. There appear to be few differences in normative sphincter ultrasound measurements between primiparous patients who had VB or CD.

Operative strategy for fistula-in-ano without division of the anal sphincter.

The treatment of perianal fistulas is diverse because no single technique is universally effective. Fistulotomy remains the most effective way of eradicating the pathology but it renders the patient at some risk of faecal incontinence, which many patients are reluctant to take. There are no data in the literature to indicate the healing rate of perianal fistulas when using an operative strategy that routinely avoids division of any part of the anal sphincter. The aim of this paper is to present the long-term results with an operative strategy that aims to avoid division of any part of the anal sphincter complex when treating all types of perianal fistulas, thereby minimising/eliminating the risk of postoperative incontinence. We report 54 consecutive cases of anal fistula that presented electively and as an emergency. Patients with known or subsequently diagnosed inflammatory bowel disease or malignancy were excluded from the study. Overall, 46 patients (37 male and 9 female) with a median age at presentation of 42 years (range: 19-73 years) were treated by lay-open of the subcutaneous tract of the perianal fistula and insertion of a loose seton for the part of the fistula tract related to the sphincter complex. The types of fistula treated were intersphincteric (89%), transsphincteric (4%) and high suprasphincteric (7%). The median length of time that the seton was left in place was 7 months (range: 1.5-24 months). The healing rate was 86% with a recurrence rate of 19% and a median follow-up duration of 42 months. Patients who are reluctant to take any risk of faecal incontinence could be treated using an operative strategy that routinely avoids division of any part of the anal sphincter complex as this has a recurrence rate that compares well with other treatment modalities.

Relapsing faecal incontinence in the elderly: a no man’s land

Background Post-obstetric neuropathic faecal incontinence is a complex disorder of impaired motor function involving the sphincters and pelvic floor, often associated with impaired rectal evacuation and anorectal anaesthesia [1]. Direct trauma to the anal sphincter complex can give immediate problems or problems later in life. The initial therapy should be conservative. Patients with anatomic sphincter defect or with extensive sphincter damage, muscle loss or pudendal neuropathy are very likely to need surgery. Several surgical approaches have been proposed, but results still remain disappointing, although quality of life seems to be improved [2]; after the initial enthusiasm, the role of artificial bowel sphincter (ABS) has been scaled-down. These problems are even harder to face in elderly patients previously operated on with poor outcome for faecal incontinence.

Ultra-low anterior resection following neoadjuvant chemoradiation for rectal cancer: The end of the 1-cm rule?

The surgical management of rectal cancer has evolved as techniques have improved and the use of preoperative multimodality therapy has gained acceptance as the standard of care. One of the most dynamic areas regarding surgical resection of rectal cancer has been the issue of an oncologically safe distal resection margin. Despite recommendations for the minimum acceptable distal margin shrinking from 5cm to 2cm and now to 1cm over the past several decades, this question remains a topic of intense debate. Such discussion centering on the impact distal margins of resection can critically affect the ability to preserve the anal sphincter complex during rectal resection for cancer. In the present era of the surgical treatment of locally advanced rectal cancers with neoadjuvant chemoradiation, the literature has supported the potential safety of a 1-cm margin for sphincter preservation without a significant risk for unresected microscopic distal intramural spread. More recently, data has emerged demonstrating no statistical difference in oncologic outcomes in terms of local recurrence or overall survival when comparing shorter distal margins to those greater than 1cm. This review examines the data in support of the 1-cm rule and discusses its validity in light of more recent reports in the modern multidisciplinary treatment era.

Magnetic Resonance Imaging Evaluation of Perianal Fistulas

PurposeThe purpose of this study was to discuss the usefulness of magnetic resonance imaging in evaluating perianal fistulas, their ramifications, extent, associated abscesses and relations with the anal sphincter complex and its role in preoperative classification. Material & methodsA retrospective study was carried out using picture archiving and communication system. Data of 58 patients presented with a clinical suspicious of perianal fistula from April 2012 to March 2013 was collected. In all patients pre contrast T2 propeller with and without fat suppression, diffusion weighted and pre and post contrast liver acceleration volume acquisition sequences were obtained. Pulse sequences were as follows: T2 propeller (TR: 7766ms, TE: 122ms), Diffusion weighted (TR: 7000ms, TE: 67ms), LAVA (TR: 7ms, TE: 3.242ms). ResultsMRI revealed a total number of 38 fistulae in 35 (60%) patients while 13 (22%) patients had only perianal sinuses. Out of these 35 patients, 4 were females and 31 were male subjects. Out of total 38 fistulae seen in these 35 patients, 11 (29%) were transsphincteric, 24 (63%) were intersphincteric and 2 (5%) were suprasphincteric. Only 1 (3%) case was extrasphincteric fistula. Twenty-six fistulae (68%) were simple, whereas 12 (32%) showed associated abscess formation, inflammation and branching course. ConclusionOur results support that MRI is the method of choice for evaluating perianal fistulae as they display the anatomy of the sphincter muscles orthogonally with a background of good contrast resolution. Moreover, with MRI we can accurately classify perianal fistulas preoperatively along with the detection of associated infection and help in planning a successful surgery.

Development of an In‐house Endoanal Ultrasound Teaching Phantom

The aim of this study was to construct an anatomically correct phantom for visualization of anal sphincter complex structures. To ake an endoanal ultrasound phantom, we experimented with a variety of commercially available materials to simulate hyperechoic, hypoechoic, and isoechoic tissue consistency. We created external anal sphincter muscle and the levator plate using stand-alone density gel and microbubbles to simulate the echogenicity of the muscles. A mold was created in a container, the muscles were inserted, and the mold was filled with high-density clear gel and allowed to fill. Once finished, the container was sealed tightly and stored for later use. To evaluate the accuracy of the model, 6 ultrasound imaging raters from different disciplines were included. The raters were administered a 6-item Internet-based interactive test using 2-dimensional images obtained from scanning the phantom. Rater agreement was determined. The Fleiss κstatistic was calculated to determine inter-rater reliability. The raters identified the structures in 32 (89%) of 36 test questions. There was good to excellent agreement among the readers. Agreement rates for visualization of the external anal sphincter, perineal body, and internal anal sphincter were 67%, 83%, and 100%, respectively. An endoanal phantom can be constructed as a simulator for endoanal sonography.

The bottom line: Iatrogenic fetal anal trauma in undiagnosed breech presentation

Injuries to the fetal head after amniotomy are well reported in literature, but injuries to the fetal anus in the breech presentation have not previously been reported. Two cases of fetal anal injury are described here, both in undiagnosed cases of breech presentation. In the first case the baby's anus was mistaken for the maternal cervix and a digital examination was performed. After the birth there was significant bruising and obvious trauma to the baby's anus. The baby did not, however, suffer any serious adverse effects. In the second case, an amniotomy hook was used to augment labour. The amniotomy hook caused an anal laceration, which fortunately did not involve the anal sphincter complex. The second baby also suffered no major adverse effects, with regards to continence. However, both babies required a general anaesthetic for assessment of their injuries, a longer stay in hospital and parental anxiety. While fetal anal injury in undiagnosed breech presentation is uncommon, it has the potential to be a life-changing injury. It is therefore critical to accurately ensure the fetal presentation, and to be aware if findings on vaginal examination are at all unusual.

Management of anal fistulas

Anal fistulas can significantly affect quality of life by either persistently discharging or intermittently occluding, causing recurrent abscess formation. They pass through the anal sphincter complex, which is responsible for maintaining continence of rectal contents (gas, liquid or solid stool). Treatment therefore aims to eradicate the fistula and preserve sphincteric function. To date, laying open the fistula (fistulotomy) is still the most effective treatment, but as it divides the sphincter muscle, it increases the risk of incontinence. For those in whom fistulotomy is not recommended, alternative strategies exist, including techniques aimed at minimising sphincter disruption, ‘sphincter-conserving’ methods or the placement of a long-term loose draining seton. This article reviews the literature on all aspects of anal fistulas, as well as their management and the requirements of postoperative care.

Colorectal Perforation by Self-induced Hydrostatic Pressure: A Report of Two Cases

BackgroundMost iatrogenic colorectal perforations occur as a result of endoscopic or fluoroscopic studies. Accidents associated with hydrostatic pressure-induced perforation are rarely reported, and self-induced hydrostatic pressure is an extremely rare cause of perforation because the anal sphincter complex may provide a protective barrier against perianal hydrostatic pressure. We present two cases of rectosigmoid colon perforation secondary to self-induced hydrostatic pressure. Case ReportsA 61-year-old man and a 45-year-old man presented with abdominal pain after forceful entry of tap water into the rectum, during rinsing of the anus after defecation in the first case, and during self-administered enema in the second case. Emergency operations were performed with the suspicion of hydrostatic pressure-induced rectal injury, and showed rectosigmoid mesenteric perforation in both cases. Resection of the diseased segment and end colostomy (Hartmann’s procedure) was performed in the first case, and primary resection and anastomosis in the second case. The pathologic results showed abrupt loss of the colonic wall in the mesenteric border, without evidence of other inflammatory disease; these findings were consistent with acute mechanical colon injury. The postoperative course in both cases was uneventful. ConclusionThese cases put forth an unusual type of colorectal injury, caused specifically by hydrostatic pressure, thus adding to the available literature on hydrostatic pressure-induced injury.

Effect of repeat acute injury on contractile function of the external anal sphincter in an animal model

Our aim was to estimate the physiologic effects of early repeat transection and repair on the contractile properties of the external anal sphincter (EAS) in a rat model. Eighty young female rats underwent anal sphincter transection and repair. After 7 days, they were randomized to repeat sphincter transection (injury-injury, n = 40) or sham operation (injury-sham, n = 40). Thereafter, the anal sphincter complex was dissected, mounted, and analyzed for contractile function 7 days, 21 days, 3 months, or 6 months after the second operation. Contractile function was also determined in 40 age-matched unoperated controls (n = 10 for each time point). Statistical analysis was performed using analysis of variance (ANOVA) with Tukey-Kramer adjustment for multiple testing. P ≤ 0.05 was considered significant. Although single injury (injury-sham) resulted in modest compromise of sphincter function, repeat injury (injury-injury) resulted in profound impairment of twitch tension, maximal tetanic responses, and maximal electrical-field stimulation (EFS) induced-force generation at 7 days. After single injury, parameters of contractile function returned to baseline uninjured levels by 21 days. In contrast, sphincter function remained reduced 21 days after repeat injury. Contractile function of sphincters from both injury-sham and injury-injury animals were no longer impaired at 3 and 6 months. In this animal model, repeat injury and repair of the EAS 7 days after the initial injury resulted in prolonged compromise of EAS function compared with single injury. Nevertheless, contractile function of the double-injured sphincter fully recovered with time, resulting in no long-term impairment.

Infliximab and surgical treatment of complex anal Crohn’s disease

Perianal fistulae in Crohn's disease are frequently complex, involve the anal sphincter complex and surgical treatment can be associated with poor healing of wounds and damage to the mechanism of continence. The aim of this study was to evaluate the efficacy and duration of response to infliximab in the long-term management of perianal fistulae in Crohn's disease in routine clinical practice. A prospectively maintained database was used to identify patients with Crohn's disease and complex anal fistulae who were treated with infliximab (primary treatment, three initial infusions followed by maintenance therapy). Patients who received infliximab for luminal disease or for enterocutaneous, peristomal or rectovaginal fistulae were excluded from this study. Fifty-two patients [25 male, median age 24 (range 15-72) years] were treated with infliximab for perianal Crohn's fistulae for a median of 66 (7-124) months. Twenty-six of the patients underwent pre-infliximab MRI scans and 38 had an examination under anaesthetic (EUA) prior to commencement of treatment, 22 of whom had seton(s) inserted into their fistulae. Maintenance therapy was possible in 42 (81%) of 52 patients. Twenty-two (42.3%) patients had a complete response to treatment, 23 (44.2%) had a partial response and 7 (13.5%) had no response. Less than complete response to infliximab was associated with a greater risk of requiring surgical intervention (Fisher's exact test, d.f. 1, P = 0.005). The response rates of Crohn's related complex perianal fistulae to infliximab are good. Complete response is associated with a reduced need for surgical intervention.