Kasr El Aini Journal of Surgery VOL., 10, NO 3 September 2009 97 The use of Pudendal Nerve Block in Hemorrhoidectomy Operations: A Prospective Double Blind Placebo Control Study Sherif Adly and Mohamed Abd El Aziz Departments of Surgery and Anesthesia Misr University for Science & Technology ABSTRACT Hemorrhoidectomy operation is usually associated with intense postoperative pain. Trials to improve surgical techniques failed to decrease postoperative pain significantly. The use of regional anesthesia although it gives a reasonable postoperative pain relief yet this is short lived and is sometimes associated with postoperative urinary retention. Finding a way of a more sustained postoperative pain relief with no added risk of urinary retention would be beneficial. This is a prospective double blind placebo controlled clinical trail.sixty patients scheduled for herorrhoidectomy operation in our hospital were recruited in this study and were randomized into three groups. Group A received general anesthesia only, group B received general anesthesia and bilateral Pudendal nerve block and group c received general anesthesia and bilateral placebo pudendal block. This trial showed a significant pain relief in group B in the night of surgery and in the first postoperative day when compared with groups A and C. It showed that the addition of pudendal nerve block to general anesthesia does not add any risk of postoperative urinary retention. In conclusion we recommend the addition of pudendal nerve block to general anesthesia in hemorrhoidectomy operation. Key words: Hemorrhoidectomy, pudendal nerve block. INTRODUCTION Hemorrhoidectomy is frequently associated with significant postoperative pain of variable duration. The pain is usually accompanied by substantial consumption of analgesics both opioid and non-opioid (1). Despite numerous attempts to modify both surgical and anesthetic regimens this problem remains clinically important (2). Pudendal nerve block has been used in many centers to decrease the postoperative pain after hemorrhoidectomy operations (3). The aim of the current study is to detect if there is any benefit to the addition of Pudendal nerve block to general anesthesia and the primary outcome variables were postoperative pain calculated by pain score, the need for opioid analgesics and the duration of hospital stay. All patients recruited in this study signed a written informed consent. The study was approved by the ethical committee in our hospital. PATIENTS & METHODS Sixty patients admitted to our hospital from February 2007 to February 2009 with the diagnosis of hemorrhoids scheduled for surgery because of their symptoms and their unsuitability for band ligation therapy were recruited in this study. Patients on oral anticoagulants, patients with American Society of Anesthesia ASA 4 or 5 and pregnant women were all excluded from the study. Those sixty patients were randomly divided into three groups. Randomization was done by the sealed opaque envelope technique. Group A is the general anesthesia only group, group B is the general anesthesia plus bilateral Pudendal nerve block group and finally group C is the general anesthesia plus bilateral placebo nerve block. Surgical technique Open hemorrhoidectomy was done in the usual fashion where skin flaps were raised next to the mucocutaneous junction to the dentate line, hemorrhoid pedicle was transfixed and hemorrhoids were excised.
Kasr El Aini Journal of Surgery VOL., 10, NO 3 September 2009 98 Protocol for general anesthesia All patients were given preoperative sedation (Midazolam 0.15 mg/kg). Induction of general anesthesia was by intravenous Fentanyl (1.5micogram/kg) and Thiopental (3-5 mg/kg) followed by endotracheal intubation facilitated by Atracuruim (0.5/kg). Anesthesia was subsequently maintained with Isoflurane 1-3% and Oxygen 30%. The Isoflurane concentration was adjusted with intension of keeping heart rate and blood pressure about plus or minus 25% of pre-induction values. Pudendal nerve block technique This technique was done for both group B and group C. For group B patients a mixture of (2% Lidocaine, 5% Bupivacaine, Fentanyl and Clonidine) was used and patients were given a total volume of injection 0.7 ml/kg (4). Patients in group C were given similar volume but of normal saline only. While the patient is in lithotomy position, four injection sites were used two anterior and two posterior. The skin of the chosen injection sites was infiltrated with 1 ml of 1% Lidocaine after aseptic skin preparation. The posterior injections were at four and eight o`clock positions five centimeters from the anal verge. A 22-gauge 10 centimeter nerve stimulator was advanced approximately 7 to 10 centimeters depending on patient size perpendicular to the skin in all planes using a stimulating current of 2.5-5 ma and 1 Hz. Appropriate stimulation of the nerve was detected by the contraction of the posterior fibers of the internal anal sphincter. Then the injection was performed. A similar procedure was done for the anterior injections at two and ten o`clock two and a half centimeters from the anal verge and at these locations the needle was advanced to only 4 to 5 centimeters. The response of Pudendal nerve stimulation at those sites is the contraction of the anterior fibers of the internal anal sphincter (4). The time needed for the performance of Pudendal nerve block was ten to twenty minutes Data collection Data were collected as regards patient`s characteristics including age, sex, body mass index (BMI) and the grade of hemorrhoid. Data were also collected as regards postoperative nausea and vomiting, urinary retention, pain score in the night of operation and in the first postoperative day. The need for opiod analgesia and the duration of hospital stay were registered. Pain score was explained to each patient as a score from zero to ten where zero means no pain and ten means unbearable pain. Pharmacological management of postoperative pain All patients were given Diclofenac potassium but opiod analgesics were given only on demand. RESULTS All the studied groups were similar as regards sex, age, Body Mass Index and hemorroidal grade. Table (1) shows no statistically significant difference between the three studied groups as regards patient`s age and BMI. Table (2) shows that patients in group B needed less opiod analgesics and had less pain in the night of surgery and in the first postoperative day when compared to patients in group A and C and this difference was found statistically significant. Also hospital stay was less in patients of group B compared to patients in group A and C and this difference is statistically significant. But as regards postoperative nausea, vomiting and urinary retention there was no significant difference between the three studied groups.
Kasr El Aini Journal of Surgery VOL., 10, NO 3 September 2009 99 Table (1): Comparison between the three studied groups as regards patient`s Age and Body Mass Index (BMI). NS is not significant, SD is standard deviation. Group Number Mean SD T P Significance Age A 20 32.9 8.996 Age B 20 33.1 9.597 0.068 0.946 NS BMI A 20 29.8 2.9842 BMI B 20 29.8 2.9842 0 1 NS Age A 20 32.9 8.996 Age C 20 32.9 9.318 0 1 NS BMI A 20 29.8 2.9842 BMI C 20 29.65 3.5285 0.145 0.885 NS Age B 20 33.1 9.597 Age C 20 32.9 9.318 0.067 0.947 NS BMI B 20 29.8 2.9842 BMI C 20 29.65 3.5285 0.145 0.885 NS Table (2): Comparison between the 3 studied groups as regards clinical parameters. Parameter Item Group A Group B Group C Sig. Sex Females Males 8 (40%) 12 (60%) 11 (55%) 11 (55%) A& C (NS) Nausea Vomiting Urinary Retention Needs for opioids Pain at night of surgery 0 1-2 3-4 Pain at first postoperative day 2-3 4-6 7-8 Hospital stay 1 2 3 Hemorrhoid Grade 2 3 4 15 (75%) 18 (90%) 2 (10%) 8 (40%) 12 (60%) 13 (65%) 10 (50%) 16 (80%) 18 (90%) 2 (10%) 20 (100%) 20 (100%) 15 (75%) 17 (85%) 3 (15%) 13 (65%) 18 (90%) 2 (10%) 16 (80%) 0(0%) 16 (80%) 1 (5%) 13 (65%) 8 (40%) A& B (NS) B& C (NS) A& C (NS) A& C (NS) B& C (HS) B & C (HS) B & C (HS) B & C (HS)
Kasr El Aini Journal of Surgery VOL., 10, NO 3 September 2009 100 DISCUSSION Pain after hemorrhoidectomy operations is usually very intense (5) leading to excessive consumption of narcotic analgesia and prolonged hospital stay (6). Attempts to improve surgical techniques have been disappointing (2). A good postoperative analgesia can be achieved with regional anesthesia as Caudal or spinal anesthesia but the postoperative analgesia is short lived and is frequently associated with some side effects like retention of urine (7). Finding a method that can provide a relatively prolonged pain relief with no increase risk of urinary retention would be beneficial. This prospective double blind placebo controlled clinical trial showed that general anesthesia GA combined with Pudendal Nerve Block PNB was associated with a statistically significant pain control at the night of surgery and in the first postoperative day, significant reduction in the use of opioid analgesia and in hospital stay. This is when compared with GA alone and GA combined with placebo Pudendal block. This study also showed that the addition of PNB to GA did not increase the incidence of urinary retention. The results of this study collaborate well with the results obtained by Naja Z et al, (3) and also with Luck et al (8), who in a prospective randomized clinical trial, found the combination of GA and ischiorectal fossa block using plain local anesthetics producing improved analgesia in the first 24 hours following hemorrhoidectomy compared to GA alone. Another benefit in adding PNB to GA is that in this study pain relief was longer than would be expected if we were using plain local anesthetics only. But the addition of clonidine and Fentanyl extended the period of analgesia to more than 48 hours. This sustained pain relief can be explained with the reduction in the nociceptive plasticity within the central nervous system (9). Another factor could have been the local effect at the level of the injured perianal nerves. Giannoni et al, described a potent effects of peripheral administration of a mixture of local anesthetics and clonidine when injected close to injured nerves or nerve endings (10). Opiod medications added to the local anesthetics have also been capable of prolonging the duration of peripheral nerve block (11). Conclusion This study proved that the addition of Pudendal nerve block to general anesthesia in hemorrhoidectomy operation leads to significant pain relief in the night of surgery and in the first postoperative day leading to a shorter hospital stay. The addition of pudendal nerve block to general anesthesia does not increase the incidence of postoperative urinary retention. REFERENCES 1. Read TE, Henry SE, Hovis RM, et al. Prospective evaluation of anesthetic technique for anorectal surgery. Dis Colon Rectum 2002; 45: 1553 60. 2. Rowsell M, Bello M, Hemingway DM. Circumferential mucosectomy (stapled haemorrhoidectomy) versus conventional haemorrhoidectomy: randomised controlled trial. Lancet 2000; 355: 779 81. 3. Naja Z, Ziade MF, Lönnqvist PA. Nerve stimulator guided pudendal nerve block decreases posthemorrhoidectomy pain. Can J Anesth 2005; 52: 62 8. 4. Pybus DA, D Bras BE, Goulding G, Liberman H, Torda TA. Postoperative analgesia for haemorrhoid surgery. Anaesth Intensive Care 1983; 11: 27 30. 5. Beattie GC, Wilson RG, Loudon MA. The contemporary management of haemorrhoids. Colorectal Dis 2002; 4: 450 4. 6. Gabrielli F, Cioffi U, Chiarelli M, Guttadauro A, De Simone M. Hemorrhoidectomy with posterior perineal block. Experience with 400 cases. Dis Colon Rectum 2000; 43: 809 13. 7. Petros JG, Bradley TM. Factors influencing postoperative urinary retention in patients undergoing surgery for benign anorectal disease. Am J Surg 1990; 159: 374 6. 8. Luck AJ, Hewett PJ. Ischiorectal fossa block decreases posthemorrhoidectomy pain. Randomized, prospective, double blind clinical trial. Dis Colon Rectum 2000; 43: 142 5.
Kasr El Aini Journal of Surgery VOL., 10, NO 3 September 2009 101 9. Aida S. The challenge of preemptive analgesia. PAIN Clinical Updates 2005; 13: 1 4. 10. Giannoni C, White S, Enneking FK, Morey T. Ropivacaine with or without clonidine improves pediatric tonsillectomy pain. Arch Otolaryngol Head Neck Surg 2001; 127: 1265 70. 11. Mays KS, Lipman JJ, Schnapp M. Local analgesia without anesthesia using peripheral perineural morphine injections. Anesth Analg 1987; 66: 417 20.
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