Nghiên cứu chẩn đoán và điều trị phẫu thuật rò hậu môn hình móng ngựa TT TIENG ANH

MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENSE 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES BUI SY TUAN ANH RESEARCH ON DIAGNOSIS AND SURGICAL TREATMENT OF HORSESHOE ANAL FISTULA Speciality : Gastroenterology surgery Code : 62720125 THE THESIS SUMMARY FOR THE DOCTOR OF PHILOSOPHY IN MEDICINE DEGREE Ha Noi - 2021 THE THESIS IS COMPLETED AT 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES Scientific tutors: Prof Nguyen Xuan Hung, PhD Prof Trinh Hong Son, PhD Oral examination 1: Oral examination 2: Oral examination 3: The thesis will be defended from University Examination Board at 108 Institute Of Clinical Medical And Pharmaceutical Sciences At : …………… on ……………… The thesis can be found at: National Library Library of 108 Institute Of Clinical Medical And Pharmaceutical Sciences LIST OF PROCLAIMED RESEARCH WORKS IN RELATION WITH THE THESIS CONTENT Bui Sy Tuan Anh, Nguyen Xuan Hung, Trinh Hong Son (2021), "Results of surgery treatment for horseshoe anal fistula”, Journal of 108 - Clinical medicine and pharmacy, Vol.16, No 4/2021, p 428-433 Bui Sy Tuan Anh, Nguyen Xuan Hung, Trinh Hong Son (2021), ”Research on the role of magnetic resonance in diagnosis and surgery of horseshoe shaped anal fistula at Viet Duc Hospital”, Viet Nam Medical Journal, Vol.498 (1), p 141 - 143 INTRODUCTION Horseshoe anal fistula (HAF) is one of the rare and complex fistulas, accounting for about 4.4% of anal fistula cases The advent of MRI has increased the possibility of diagnosing and treating rectal prolapse Studies show that MRI is very valuable when identifying internal fistulas (with a detection rate of 90-97%), sensitivity 95.5-96%, specificity 80%, assessing the degree of involvement The relationship of the fistula to the sphincter system (accuracy reached 70-91%) Thereby helping to orient the treatment strategy in cases of HAF, avoiding damage to many sphincters and reducing the recurrence rate The combination of preoperative MRI and surgery techniques has contributed to improving the effectiveness of treatment of HAF However, due to the diversity in lesion characteristics and treatment methods, the results of anal fistula surgery in studies around the world still fluctuate with success rates from 88 to 94.4%, recurrence rate 2.2 - 21% In Vietnam, the diagnosis and treatment of HAF are still challenging and not yet agreed upon There have been many studies on HAF, but no study has fully evaluated the value of MRI in identifying HAF, relating the fistula to the sphincteric system, thereby determining direction and selection of surgical methods to increase the success rate and avoid complications of anal incontinence For the above reasons, we conducted the topic: "Research on diagnosis and surgical treatment of horseshoe anal fistula" with two objectives: Describe clinical features, determine the value of MRI in the diagnosis of horseshoe anal fistula Evaluation of surgical results of horseshoe anal fistula THE NEW MAIN SCIENTIFIC CONTRIBUTION OF THE THESIS The study was conducted on 56 patients diagnose HAF and treated in Viet Duc hospital from January 2016 to April 2019 - Diagnosis HAF: Patients with external accounted for 51.8% The distance from the external to the anal margin averaged 2.6 cm MRI has a high value in diagnosing HAF with an internal fistula finding rate of 62.5%, sensitivity and specificity of 100% The diagnostic matching rate of MRI and surgery in the forms of intersphincteric fistula, transsphincter fistula, suprasphincter fistula and extrasphincter fistula were 93.3%, 91.7%, 84,6% and 16.7% - Treatment results: 51.8% of the cases were fistulotomy and put drainege, 26.8% fistulotomy, 7.1% fistulectomy, 14.3% combined opening + put seton and drainege the fistula Early complications 12.6% The the mean time of wound healing was 10.2 weeks Recurrence 12.5% Factors associated with recurrence: Long disease duration, history of anal abscess/fissure surgery, no internal fistula found, fistula above and outside the sphincter At the end of the study, 100% of patients were very satisfied with the treatment results, there were no cases of recurrence or loss of anal incontinence These contributions are realistic and contribute to emphasizing the role of MRI in the diagnosis and evaluation of horseshoe anal fistula Thereby orienting the selection of appropriate treatment methods to help reduce the rate of recurrence and complications after surgical to treat horseshoe anal fistula STRUCTURE OF THE THESIS This thesis consists of 118 pages: pages of introduction, 32 pages of literature review, 19 pages of research methods, 27 pages of research results, 35 pages of discussion, pages of conclusion, page of recommendation; research works, 37 tables, 06 graphs, 28 figures; 105 referencesincluding 28 in Vietnamese and 77 in foreign languages Chapter LITERATURE REVIEW 1.1 Anatomy – Physiology of the anorectal region 1.1.1 Anatomy 1.1.1.1 Shape and structure 1.1.1.2 Annual holes 1.1.1.3 Hermann and Desfosses gland 1.1.1.4 Lines that limit the anorectal region 1.1.1.5 The cavity around the anus rectum 1.1.1.6 Anorectal sphincter system 1.1.2 Physiology of the autonomous function of the anus 1.1.2.1 Mechanical factors 1.1.2.2 Physiological factors 1.1.2.3 Neurological factor 1.1.2.4 Sphincter factor 1.1.2.5 Anatomical factors 1.2 Horseshoe anal fistula 1.2.1 Etiology and pathogenesis Horseshoe anal fistula is a complex fistula in which fistulas arise from a deep posterior anal cavity abscess extending into the rectal fossa with unilateral or bilateral extension branches of the fistula tract forming a horseshoe-shaped fistula or abscess 90% of abscesses, horseshoe-shaped fistula located in the posterior half of the fistula tract, many branches, related to the anal sphincter system, making it difficult to diagnose and treat 1.2.2 Clinical 1.2.2.1 Acute stage (abscess): Manifestation: Swollen, hot, red, painful mass near the anus or spreading to the buttocks or perineum 1.2.1.2 Fistula stage: Abscess spontaneously ruptures or is incompletely incision made to create a fistula that drains fluid from the fistula tract to the skin near the anus 1.2.3 Subclinical 1.2.3.1 X-ray of the fistula with contrast 1.2.3.2 Endorectal Ultrasound 1.2.3.3 Research on the value of MRI in the diagnosis of HAF In recent years, the advent of anorectal MRI has increased the diagnostic and treatment capabilities of HAF Studies show that MRI is very valuable when identifying internal fistulas (with a detection rate of 90 - 97%), sensitivity 95.5 - 96%, specificity 80%, assessing the degree of involvement The relationship of the fistula to the sphincter system (accuracy reached 70 - 91%) A study by the American Society of Anorectal Surgery in 2005 found the ability of MRI to detect fistulas with a sensitivity of 95.5%, a specificity of 80%, and an accuracy of 94% Currently, MRI is increasingly used in the diagnosis and evaluation of HAF Thereby helping to orient the treatment strategy in cases of HAF, avoiding damage to many sphincters and reducing the recurrence rate 1.2.4 Classification of anal fistula 1.2.4.1 Classification of abscesses near the anus 1.2.4.2 Classification of anal fistula * Classification according to Parks: Intersphincteric fistula (type I), transsphincter fistula (type II), suprasphincteric fistula (type III), extrasphincter fistula (type IV) * Classify St James's by MRI into grades: I, II, III, IV, V 1.3 Treatment of horseshoe anal fistula 1.3.1 History 1.3.2 Surgery to treat horseshoe anal fistula Principle: Identify and treat the internal fistula, open or drain the fistula well, ensuring the anal sphincter function 1.3.2.1 Abscess stage: Incision to drain the pus, drain the abscess, ligation or cut the fistula tract (if a fistula is found in the fistula tract) 1.3.2.2 Fistula stage - Fistulotomy or Lay - open: An incision opens the fistula vertically from the external fistula to the internal fistula - Fistulectomy: The cure rate is high with removal of all lesions, however this surgery is still considered in each case due to the high rate of anal incontinence - Seton placement: For the purpose of draining fluid (drainage seton) or cutting the fistula "gradual" (cutting seton) so that the fistula heals while preserving sphincter function - Modified Hanley and Hanley techniques Deep drainage of the posterior anal space, fistula resection was performed only in the main branch and the lateral branches were left to heal on their own Today, there are some modifications to Hanley's process, which use a seton to slowly cut the primary fistula tract - Transfer of rectal mucosal flap: Surgery to remove part of the fistula, then transfer the flap to cover the internal fistula - Ligation of the intersphincteric fistula (LIFT): Ligation and removal of the fistula in the intersphincter space without cutting the sphincter - Video-assisted anal fistula treatment (VAAFT): Using a laparoscope inserted into the fistula through the external opening, clean and remove the dirt in the fistula with endoscopic pliers, then close the internal fistula 1.4 Research on the results of surgery to treat HAF 1.4.1 In the world Today, the combination of MRI preoperative assessment as well as the development of surgical methods have contributed to improving the effectiveness of treatment of HAF However, due to the diversity in lesion characteristics and treatment methods, the results of surgery to treat HAF in studies around the world are still quite variable with success rate, recurrence rate and incontinence after surgery, Koehler A with 42 patients with HAF showed that the success rate was 88%, recurrence was 12% Falih N surgery 28 HAF patients with improved Hayley method followed up after months with results: recurrence rate 10.7% In 2021, Asami Usui studied 139 HAF patients who were treated by the method of completely removing the HAF into stages to minimize damage to the sphincter and no incontinence After surgery, the results showed that: The average healing time was 13.4 weeks, the average follow-up was 25.1 weeks, there were 12 patients with recurrence (9.1%), the average time of recurrence was 18.2 weeks, no patient with incontinence after surgery 1.4.2 In Viet Nam In 2018, Nguyen Ngoc Anh studied 40 HAF patients: healing time 11.25 weeks, there was patient with grade anal incontinence, recurrence 17.5% Pham Thi Thanh Huyen had 5.1% postoperative bleeding complications, 100% of patients had good control of anal autonomic function according to CCIS scale, recurrence was 5.5% Chapter OBJECTIVES AND METHODS 2.1 OBJECTIVES The patient was diagnosed with HAF by pre-operative MRI and the characteristics of intraoperative lesions, and received surgical treatment at Viet Duc Hospital, from January 2016 to April 2019 * Selection criteria - Patients was diagnosed with HAF based on intraoperative lesions - Patients had an MRI analrectal scan before surgery - Patients received surgical treatment at Viet Duc Hospital - Patients agrees to participate in the study, complete medical records according to research criteria * Exclusion criteria - HAF patients but did not have preoperative MRI or surgery at Viet Duc Hospital - Patitents with abscesses, rectal prolapse secondary to other anorectal pathologies: prostate abscess, pelvic inflammatory disease, anal fistula caused by Crohn's, tuberculosis; rectovaginal fistula; Anal fissure in immunocompromised patients, anal rosacea secondary to local radiotherapy, after trauma - Patients does not agree to participate in the study, the records are not enough information according to the research criteria 2.2 METHODS 2.2.1 Research design and sample size - Prospective descriptive study, with longitudinal follow-up - Convenient template selection 2.2.2 The method of data collection 2.2.3 Diagnostic MRI and surgery treatment of HAF were performed in the study 10 Chapter RESULTS 3.1 Clinical features and value of MRI in the diagnosis of HAF 3.1.1 Clinical features - Mean age of the patients is 38.3 ± 11.3 years (16 – 65) - Male patients accounted for the majority with 89.3% - History of surgery to treat abscesses /anal fissures: 53.6% of patients had surgery, of which 8.9% had surgery or more times - Comorbidities: 30.4% hemorrhoids, 3.6% diabetic patients - Disease duration: average 4.1 ± months 78.6% of patients had the disease for less than months - Symptoms: 64.3% of patients had symptoms of swelling and pain in the anus area and 41.1% of fluid and pus near the anus - Clinical examination of the anorectal area + 48.2% of patients did not detect an external fistula + 33.9% of patients had external fistulas and 5.4% of patients had ≥ external holes + Distance from the external to the anal margin is 2.6 ± 0.9 cm 3.1.2 Value of MRI in the diagnosis of HAF 3.1.2.1 Fistula tract Table 3.7 Classification of the fistula on MRI according to Parks Classification of the fistula on MRI according to Parks Number of patients (n = 56) Ratio (%) Intersphincteric 28 50.0 Transsphincteric 11 19.6 Suprasphincteric 11 19.6 Extrasphincteric 10.8 Comment: Intersphincteric accounted for the majority with 50% 11 Table 3.8 Diagnostic accuracy of fistula classification according to MRI Classification of the fistula according to Parks MRI (n = 56) Intraoperative (n = 56) Accuracy (%) Intersphincteric 28 30 93.3% Transsphincteric 11 12 91.7% Suprasphincteric 11 13 84.6% Extrasphincteric 16.7% Comment: The accuracy of MRI compared with intraoperative assessment of the intersphincteric fistula was the highest with 93.3% 3.1.2.2 Evaluation of internal fistula - The rate of detecting internal fistula on MRI before magnetic surgery is 62.5% - Sensitivity, specificity and diagnostic value of MRI when detecting internal compared with the evaluation at surgery is 100% - Value of MRI when locating internal compared to surgery: Sensitivity 100%, specificity 0%, Positive predictive value 85.7% 3.2 Evaluation of the results of surgery to treat the HAF 3.2.1 Results intraoperative - Assessment of damage + 35 patients found fistula during surgery, accounting for 62.5% + 35/ 35 cases (100%) found 01 internal fistula + The way to determine the internal fistula is mainly using stylet and hydrogen peroxide, accounting for 57.1% + 78.2% of internal fistulas were found at the o'clock position 12 Table 3.14 Classification of the fistula according to Parks Classification of the fistula on MRI according to Parks Number of patients (n = 56) Ratio (%) Intersphincteric 30 53.6 Transsphincteric 12 21.4 Suprasphincteric 13 23.2 Extrasphincteric 1.8 Comment: Intersphincteric fistula accounted for the majority with 53.6% Bảng 3.1 Surgery methods Surgery methods Number of patients (n = 56) Ratio (%) Fistulotomy 15 26.8 Fistulectomy 7.1 Fistulotomy and put drainege 29 51.8 Combined opening + put seton and drainege the fistula 14.3 Comment: 51.8% of the cases were fistulotomy and put drainege, 26.8% fistulotomy - Intersphincteric fistulas were mainly treated by the method of fistulotomy and put drainege, accounting for 51.8% and fistulotomy 26.8% - The cases of suprasphincteric and extrasphincteric fistula were fistulotomy and put drainege 7/13 suprasphincteric fistulas (53.9%) were combined opening + put seton and drainege the fistula - Operative time average 55.3 ± 16.2 minutes (30 – 120 minutes) 3.2.2 Short-term outcomes 3.2.2.1 Time and severity of pain after surgery - Pain after surgery on average 4.2 ± 1.7 days (2 – days) 13 - The pain level according to the VAS scale gradually decreased from the first day to the third day By the third day after surgery, 53.6% of patients had moderate pain, 35.7% had very mild pain, no patient has much pain 3.2.2.2 Early complications Bảng 3.2 Early complications Early complications Number of patients (n = 56) Ratio (%) Bleeding 3.6 Difficulty urinating 1.8 Urinary retention 7.2 Total 12.6 Comment: Early complications 12.6% 3.2.2.3 Evaluation of anal autonomy function at the time of hospital discharge At the time of hospital discharge, 35.7% of patients did not have anal incontinence, 57.1% had grade I incontinence 3.2.3 Long-term outcomes The mean follow-up time was 34.8 ± 12.6 months (20-48 months) The mean time of wound healing was 10.2 ± 3.7 weeks (5-20 weeks) - The fistulotomy and put drainege group had the longest healing time with an average of 13.6 ± 4.5 weeks (p < 0.05) - Anal sphincter function improved gradually at the time of follow-up The rate of normal anal autonomy (grade 0) gradually increased over time from to 12 months was 60.7%, 85.7% and 92.9% - Recurrent anal fistula and related factors: + There are 7/56 patients with fistula recurrence (12.5%) The majority of recurrent lesions are abscesses at the site of the primary fistula (5/7 cases), which were opened by surgery and cleaned the abscess + There was no difference in the mean age of recurrence and no recurrence groups (p = 0.15 > 0.05) 14 Table 3.28 Relation to recurrence and disease duration Disease duration (months) Group Number of patients Mean Min Max No recurrence 49 4.05 ± 5.18 0.07 Recurrence 7.16 ± 8.07 24 p = 0,008 Comment: The time of disease before surgery in recurrence group was longer than in the no recurrence group (p < 0.05) - The rate of recurrence was higher in the group of patients who had a history of surgery for abscess/anal drainage (20.0%) higher than those who had never had surgery (3.8%) (p = 0.0001 < 0.05) - The rate of recurrence was higher in the group of patients with no internal fistula found (23.8%) than in the patients with internal fistula (5.7%) (p = 0.004 < 0.05) Table 3.31 Relation to recurrence and classification of primary fistula Group Classification of primary fistula No recurrence Recurrence Intersphincteric (n = 30) 30 (100%) (0%) 30 (100%) Transsphincteric (n = 12) 11 (91.7%) (8.3%) 12 (100%) Suprasphincteric (n = 13) (61.5%) (38.5%) 13 (100%) Extrasphincteric (n = 1) (0%) (100%) (100%) Total (n = 56) 49 (87.5%) (12.5%) 56 (100%) p = 0.031 Total 15 Comment: The observed significance level p < 0.05 -> There is a difference in recurrence rate between groups of patients with different classification of primary fistula The recurrence rates in the extrasphincter, suprasphincter and transsphincter fistula groups were 100%, 38.5% and 8.3% - There was no difference in the recurrence rate between the groups of patients applying different surgical methods (p > 0.05) - At the time of follow-up, the majority of patients were satisfied with the treatment results, accounting for 60.7%, 78.6%, 89.3% and 100% Chapter DISCUSSIONS 4.1 Clinical features and value of MRI in the diagnosis of HAF 4.1.1 Clinical features 4.1.1.1 Age, gender The study results showed that the mean age of the patients was 38.3 ± 11.3 (16 - 65 years), male accounted for 89.3% Similar to other HAF studies, the mean age of the patients is about 35 - 50.3 years, the majority of male patients are from 59.9 to 82.7% 4.1.1.2 History of surgery for abscesses, anal discharge The results of the study showed that: 53.6% of patients had a presurgery for abscess/anal drainage, of which 30.4% had surgery once; 14.3% surgery times and 8.9% surgery or more times, mean 1.1 ± 1.8 times, at least 0, at most times Similar to other studies on HAF, the proportion of patients with a history of surgery for anal abscess/fistula ranged from 27.1 to 91% We have the same opinion with the authors: Patients with a history of surgery for anal abscess/ fistula, this time recurrence is often 16 complicated lesions, old surgical scars cause anal deformity, causing difficulties clinical examination, diagnosis and surgical treatment 4.1.1.3 Comorbidities The comorbidities of the patient group in the study included: 30.4% hemorrhoids, 5.4% anorectal polyps and 3.6% type II diabetes Similar to other authors 4.1.1.4 Duration of disease The mean duration of disease in the study was 4.1 ± 6.0 months (3 days - 24 months) Similar to the study of Nguyen Xuan Hung, Inceoglu R and Browder L.K 4.1.1.5 Physical symptoms In the study, patients showed swelling and pain in the anus area, accounting for 64.3% Symptoms of discharge, purulent discharge near the anus were found with 41.1%; The anus is painful, accompanied by itching 17.9% Depending on the stage of the disease, the patient's symptoms on admission may vary 4.1.2 Value of MRI in the diagnosis of HAF 4.1.2.1 Fistula tract Result of fistula MRI in our study: intersphincteric fistula accounted for 50%; transsphincter fistula 19.6%; Sphincter fistula 19.6% and extrasphincter fistula 10.8% The accuracy of MRI compared with intraoperative assessment of intersphincteric fistula was the highest with 93.3%, transsphincteric fistula 91.7%, suprasphincteric fistula 84.6%, accuracy of MRI when diagnosis of extrasphincter fistula was lowest (16.7%) The study of Rosa G MRI showed 38.7% intersphincter fistula, 52.6% transsphincter fistula, 2.6% suprasphincter fistula, 4% extrasphincter fistula According to Singh K, the ability of MRI to detect fistula with sensitivity 95.5%, specificity 80%, accuracy is 94% 17 4.1.2.2 Evaluation of internal fistula The study results showed that: MRI scan detected 35 patients with internal fistula, accounting for 62.5% Similarly, the rate of finding an internal fistula on MRI of Nguyen Ngoc Anh is 67.5% According to Buchanan G.N., the ability to detect an internal fistula based on clinical examination is 78%, endoscopic ultrasound 91% and MRI scan is 97% The study showed that: 35 cases of internal fistula detected by MRI, when compared with the surgical results, also gave the same results Thus, MRI can detect internal fistula with sensitivity and specificity of 100%, positive predictive value of 85.7% Similarly Singh K MRI has a sensitivity of 87.5%, a specificity of 95.2%, a positive diagnostic value of 77.8% and a negative diagnostic value of 97.6% in detection the exact location of the internal fistula 4.2 Evaluation of the results of surgery to treat the HAF 4.2.1 Results intraoperative 4.2.1.1 Evaluation of internal fistula Accurate determination of the location of the internal fistula is especially important to help assess the entire fistula lesion prior to initiating surgery The results of the study showed that 62.5% of patients found fistula during surgery and 37.5% did not find it The method of determining the internal fistula was mainly using a combination of stylet and hydrogen peroxide, accounting for 57.1%, patients (5.7%) using only stylet, 10 patients (28.6%) using only stylet hydrogen peroxide and patients (8.6%) methylene blue pump Most of the authors have the same opinion that the method of finding the internal fistula in the direction of MRI combined with hydrogen peroxide pump and stylet from the external fistula gives good efficiency 18 4.2.1.2 Number and location of internal fistula Intraoperative assessment found that 100% of patients had an internal fistula Regarding the distribution of hole positions, 78.2% were found at the o'clock position The results are similar to other studies, the authors suggest that most cases of anal discharge start from the deep posterior anal cavity located in the posterior half of the anus and drain to the anal tract at o'clock Pankaj Gar sees the hole in mid lane after 85.1%, mid lane before 8.5% 4.2.1.3 Leakage classification according to Parks Classification of intrasphincteric fistula: intersphincter fistula found 53.6%, transsphincter fistula 21.4%, suprasphincter fistula 23.2% and extrasphincter fistula accounted for 1.8% Similarly, Falih Noori found the rate of intersphincter fistula is 45%, transsphincter fistula 30%, suprasphincter fistula 20%, extrasphincter fistula 5% Pankaj found HAF to be intersphincter in 57.4%, transsphincter in 4.3%, and in both midmuscular and transsphincter in 38.3% 4.2.1.4 Surgery methods - Fistulotomy (Lay – open) In our study, 15 patients (26.8%) had surgery to completely open the fistula The rate of fistulotomy in the group of patients had an intersphincteric fistula 41.4%, a transsphincter fistula 23.1%, there were no cases of fistula on the suprasphincter and extrasphincteric According to the authors, the indication for opening is applicable to most transsphincteric, intersphincteric fistulas, even with some transsphincteric horseshoe fistulas IIa or IIb - Fistulectomy The results of the study had patients with fistulectomy, accounting for 7.1% In which, intersphincter 6.9%, transsphincter 15.4% No patient had a suprasphincter or extrasphincter fistula 19 - Fistulotomy and put drainege In the study, 51.8% of patients had partial fistula opening and drainage placed Indications for two-stage surgery in transsphincter fistulas (fissures with many nooks and crannies, widespread necrotizing inflammation), fistulas on the sphincter In case of transsphincteric fistula, the fistula is small, a single line, without nooks and crannies, after removing all the fistulas, cleanly cut, sew and close the internal fistula and part of the sphincter - Combined opening + put seton and drainege the fistula This is a modification of the Hanley surgery but in this case the primary fistula resection was performed using Seton Here, the deep posterior anal space is accessed for cleaning and drainage through the opening of the external fistula The superficial external sphincteric bundle is dissected along its fibers in the deep posterior anal space and a Seton is placed for ostomy to medial ossium in the posterior midline to progressively resect the fistula, or to mark the fistula if perform two-stage surgery In our study, there were patient (14.3%) who had surgery to partially open the fistula + seton and drain, in which case of high transsphincteric fistula and cases of supramuscular fistula tighten These are all patients with a deep posterior anal cavity abscess combined with a high fistula at the o'clock position, so we decided to partially open the fistula and drain the deep posterior anal space by Kehr and set the seton to cut the fistula The authors recommend this method as a suitable option for high horseshoe-shaped abscesses Seton has both drainage effect and gradually cuts off the sphincter, thereby minimizing the risk of loss of anal control after surgery 4.2.1.5 Operative time: 20 The results of the study showed that the average operative time was 55.3 ± 16.2 minutes (30 - 120 minutes) Similar to other authors 4.2.2 Short-term outcomes 4.2.2.1 Time and severity of pain after surgery The study found that the average time to use analgesia after surgery was 4.2 ± 1.7 days, the shortest was days, the longest was days The pain level according to the VAS scale gradually decreased from the first day to the third day By the third day after surgery, 53.6% of the patients had moderate pain, 35.7% had very mild pain, none of the patients had any pain much 4.2.2.2 Early complications We met patients with bleeding, accounting for 3.6%, who were treated with hemostatic dressings In addition, 7.2% of patients with urinary retention required catheterization and the catheter was removed after 24 hours Similar to other authors 4.2.2.3 Evaluation of anal autonomy function at the time of hospital discharge At the time of discharge, 35.7% of patients did not have anal incontinence, 57.1% had grade I incontinence (didn't actively control gas but still kept loose and solid stools) and 7.2% grade II autonomic disorder 73.3% of patients in the completely open group did not have anal incontinence patients with grade II incontinence were in the group of surgery to open a part of the fistula in combination with seton and drainage 4.2.3 Long-term outcomes 4.2.3.1 Wound healing time The study found that the average wound healing time was 10.2 ± 3.7 weeks, the shortest was weeks, the longest was 20 weeks The group of patients who underwent fully open surgery combined with seton placement and fistula drainage had the longest healing time 21 with an average of 13.6 ± 4.5 weeks (p < 0.05) Similarly, the wound healing time in Nguyen Ngoc Anh's study was 11.25 ± weeks Inceoglu R is 12 ± weeks 4.2.3.2 Evaluation of anal autonomy function at the time of follow-up The study results showed: Anal sphincter function improved gradually at the time of follow-up The rate of normal anal autonomy (grade 0) gradually increased over time from to 12 months was 60.7%, 85.7% and 92.9%, respectively At the end of the study, 100% of patients had normal anal autonomy No patient had autonomic dysfunction Similar to Koehler A, grade anal incontinence was found in grade 1, 9.5%, grade was 4.8%, followed up 58 months after surgery, there were no patients with anal incontinence 4.2.3.3 Recurrence The study had patients with recurrence after surgery, accounting for 12.5% In which patient recurrence after months, patients recurrence after months and patient recurrence after 12 months Factors associated with recurrence include: long duration of disease (p=0.008), history of surgery for abscess/anal drainage (p=0.0001), no internal fistula found (p=0.004) ), superior and extrasphincter fistulas (p=0.031) The research of Browder L.K and Pezim M.E reported the recurrence rate after the horseshoe repair from to 21% In 2021, Asami Usui studied 139 patients with a HAF, the average follow-up time was 25.1 months with 12 patients with recurrence (9.1%) Falih Noori I showed a recurrence rate of 10.7% in patients with suprasphincteric fistula and diabetes 4.2.3.4 Patient satisfaction Our study found that at the time of follow-up, the majority of patients felt satisfied with the treatment results, accounting for 60.7%, 78.6%, 89.3% and 100%, respectively The proportion of patients who 22 were not satisfied with the treatment results at month, months and 12 months were 3.6%, 7.1% and 3.6%, respectively, due to recurrent or spontaneous disorders owner of the anal sphincter CONCLUSION The study of 56 horseshoe anal fistula patients who were surgically treated at Viet Duc Hospital, from January 2016 to April 2019, we have the following conclusions: Clinical features and value of MRI in the diagnosis of HAF Clinical features Mean patient’s age: 38.3 ± 11.3 years Male was 89.3% 53.5% have a history of surgery for fistula/ anal abscess Mean duration of disease 4.1 ± months 64.3% had symptoms of swelling and pain in the anal area, 41.1% had fluid near the anus 51.8% of patients had external fistula The mean distance from the external fistula to the anal margin was 2.6 ± 0.9 cm Value of MRI in the diagnosis of HAF The accuracy of MRI in diagnosis horseshoe anal fistula in intersphincteric, transsphincteric, suprasphincteric and extrasphincteric fistulas were 93.3%, 91.7%, 84.6% and 16.7% MRI found internal fistula in 62.5% of cases, the diagnosis rate of horseshoe anal fistula by MRI with sensitivity and specificity was 100% Evaluation of the results of surgery to treat the HAF Results intraoperative 62.5% found an internal fistula Of which 78.2% of internal is at the o'clock position 23 Classification of intrasphincteric fistula: 53.6% intersphincter fistula, 21.4% transsphincter fistula, 23.2% suprasphincter fistula and 1.8% extrasphincter fistula Surgical method: 51.8% of the cases were fistulotomy and put drainege, 26.8% fistulotomy, 7.1% fistulectomy, 14.3% combined opening + put seton and drainege the fistula Operative time average 55.3 ± 16.2 minutes Short-term outcomes Pain after surgery on average 4.2 days, early complications 12.6% At the time of hospital discharge, 35.7% of patients did not have anal incontinence, 57.1% had grade I incontinence Long-term outcomes The mean follow-up time was 34.8 months The mean time of wound healing was 10.2 weeks Anal sphincter function gradually improved, at the end of the study, 100% of patients with anal autonomy were normal Recurrence 12.5% Factors associated with recurrence: Long disease duration, history of anal abscess/fissure surgery, no internal fistula found, fistula above and outside the sphincter The rate of normal anal continence increased gradually over the follow-up time from to 12 months was 60.7%, 85.7% and 92.9% At the end of the study, 100% of patients were very satisfied with the treatment results, there were no cases of recurrence or loss of anal incontinence 24 RECOMMENDATION It is necessary to develop a diagnostic procedure and select the appropriate surgical method for the lesion: + Preoperative anorectal MRI should be performed to assess lesions in patients clinically diagnosed with horseshoe anal fistula + For patients with confirmed diagnosis of horseshoe anal fistula, they should be treated surgically at the hospital level with a team of specialized anorectal surgeons Continue to evaluate the results of treatment after surgery, especially to find out the cause of recurrence and the relationship, with a longer study period: 5, 10 and 20 years ... incontinence - Seton placement: For the purpose of draining fluid (drainage seton) or cutting the fistula "gradual" (cutting seton) so that the fistula heals while preserving sphincter function - Modified... Viet Nam In 2018, Nguyen Ngoc Anh studied 40 HAF patients: healing time 11.25 weeks, there was patient with grade anal incontinence, recurrence 17.5% Pham Thi Thanh Huyen had 5.1% postoperative... stage (abscess): Manifestation: Swollen, hot, red, painful mass near the anus or spreading to the buttocks or perineum 1.2.1.2 Fistula stage: Abscess spontaneously ruptures or is incompletely incision