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JI( TH NA UP .R DR AK UP .R Anesthesia in Proctology DR H NA T 5 ) INTRODUCTION Among good operative conditions to perform proctological surgery optimal anesthesia is mandatory. n Efficacious anesthesia for proctology should fulfill at least five criteria: deep and lasting analgesia of the anal canal; blood-free operative field; no side effects on the bladder; suppression of vagal reflex; easy use in outpatients; n Several different types of techniques can be used: local anesthesia; local infiltration analgesia associated with sedative or light general anesthesia; locoregional or posterior perineal block; caudal anesthesia; epi-and peridural anesthesia; general anesthesia. Local anesthesia, posterior perineal block, and caudal block give good operating conditions to perform nearly all proctological procedures. These methods do not require a long bed rest as compared to spinal block. They may be performed by the surgeon and may be used on outpatients.1,5,7,10,11,12 Careful patient selection is nevertheless necessary. The proctologist should be able to recognize and treat any cardiovascular and respiratory complication; adequate resuscitation equipment must be immediately accessible. UP AK NA TH ) # .R CHOICE OF LOCAL ANESTHETIC AGENTS DR .R UP NA TH JI( DR Local anesthetic agents may be classified according to their intrinsic potency compared to that of procaine, to the time needed until the onset of action, and to the duration of anesthesia 5,14,16,17 (Table 5-1). All local anesthetic agents have a relaxant effect on the musculature of blood vessels resulting in vasodilatation. This effect is directly related to the potency of the drug: more potent and long-acting agents produce a greater and longer duration of vasodilatation. The most frequently used drug is lidocaine, which has a great security margin. Without any vasoconstrictor, the maximal dosage is 200 mg; if vasoconstrictors 163 6 1 10 2 1,5 2 2 *In comparison to procaine. Procaine Tetracaine Lidocaine Prilocaine Hostacaine Mepivacain Tolycaine Bupivacaine Toxicity* DRTable 5-1. Dosage and toxicity of local anesthesic agents .R Maximal dosage UP Analgesic power*N Without adrenaline With adrenaline Onset of action (mg) (min) A(mg)T H 1 500 1000 5-10 JI( 10 100 20 10 DR 500 2 200 <2 .R600 2 400 <2 4 ? ?U <2 PA 2 300 500 K <2-25 250 600 NA5-10 8 150 150 TH ) 45 - 60 min 60 - 90 min 60 - 120 min 60 - 120 min 60 - 120min 60 - 120 min 60 - 90 min 5 - 15 hours Duration of action 164 5 ❑ Anesthesia in Proctology 165 5 ❑ Anesthesia in Proctology are added, the maximum dosage increases to 500 mg that means a total amount of 100 ml 0,5% lidocaine. Bupivacaine and Naropin result in a long lasting anesthesia of several hours. Naropin is less cardiotoxic than Bupivacine.13 USE OF A VASOCONSTRICTOR UP AK NA T H ) A vasoconstrictor may be added in order to diminish the risk and severity of induced vasodilatation and to reduce tissular resorbtion. Epinephrine or adrenaline has been widely used at following concentrations: n Adrenaline or epinephrine: 1:200 000. n Ornithine-vasopressine (POR 8): 1 int. unit in 4 to 10 ml. The use of these drugs result in low local capillary bleeding, reduces resorbtion, less toxic side effects and prolonged duration of analgesia. They have nevertheless their own toxicity. Caution is mandatory in cases of hypertension as well as coronary and cerebrovascular disease and on old patients. The dosage should be reduced accordingly.8 .R USE OF NA - BICARBONATE NA TH JI( DR Lidocaine has a low pH value of about 6. Injection of the drug results in a painful burning sensation. If 1 ml of an 8.4% solution of Na-bicarbonate is added to 9-10 ml of lidocaine the burning effect disappears and patients comfort is improved. The pH increases to 7.4. The nervous blockade is speeder and lasts longer. If a lidocaine-adrenaline solution is used, 2 to 2.5 ml of 8.4% Na-bicarbonate should be added.10 USE OF HYALURONIDASE DR .R UP Hyaluronidase is a mucolytic enzyme, which allows anesthetic solutions to spread into the tissue by inactivating the hyaluronic acid present in the interstitial space. It reduces swelling and increases absorption.18 Hyaluronidase is not toxic and rarely produces allergic reactions. Thanks to the increased diffusion of the anesthetic solution, a smaller volume may be used, but toxic reactions to the local anesthetic agent and to the vasoconstricting drug may be increased.2 Usually 150 units hyaluronidase are added to 50 ml solution. Hyaluronidase is rarely used nowadays. SYSTEMIC TOXICITY Surgeons should be well aware of toxic reactions due to local anesthetics and to vasoconstrictors; they must be able to manage and to treat them.3,4,5,11,12 SYSTEMIC TOXICITY OF LOCAL ANESTHETICS Allergic reactions to local anesthetics are rare and are usually limited to ester-linked agents, such as procaine and tetracaine, and not to amino-linked drugs like lidocaine and prilocaine. The majority of systemic reactions are due to 166 5 ❑ Anesthesia in Proctology Table 5-2. Signs and symptoms of local anesthetic toxicity PR interval I QRS duration I Cardiac output I H ) Blood pressure l PR interval II NA T Speach difficulties Confusion Vomiting Unconsciousness Muscle twitching Tremor of face and Extremities AK QRS duration II UP Sinus bradycardia Hypotension Coma Generalized convulsions Respiratory problems Respiratory arrest Atrioventricular block Asystole TH JI( Severe Dizziness Lightheadedness Daze Tinnitus Tremor Agitation Disorientation .R Medium Cardiovascular effects DR Light Central nervous system effects DR .R UP NA inadvertent intravascular injection or to administration of an excessive dose. Toxic reactions can be classified, according to their severity, as light, medium, or severe (Table. 5-2). Central nervous system excitation represents the earliest manifestation of toxicity. Respiratory and cardiovascular complications result from direct cardiac and vascular action due to overdosage or from indirect action by blockade of the autonomic nerve fibers. Bupivacaine causes the greatest cardiac toxicity.9 TOXICITY OF VASOACTIVE DRUGS If vasoactive drugs have been injected with local anesthetics, side effects due to them should also be considered and recognized (Table 5-3).5,8 Treatment is different according to whether toxic reactions are due to local anesthetics or to vasoconstrictors, especially in the most severe forms. Oxygen should be administered and sedatives injected in cases of arrhythmia or tachycardia; i. v. lidocaine or B-blockers should be considered in cases of toxic reactions due to vasoconstrictors. Electric defibrillation may be necessary. To prevent severe complications some rules must be observed (Table 5-4). 167 5 ❑ Anesthesia in Proctology Table 5-3. Side effects due to vasoconstrictors NA T H ) - Apprehension - Excitation - Sweating - Tremor - Palor - Dizzines - Hypertension - Arrythmia - Tachycardia TECHNIQUE OF LOCAL ANESTHESIA DR .R UP NA TH JI( DR .R UP AK Local anesthesia is useful for many minor anorectal procedures not requiring muscular relaxation. Indications to local anesthesia are very restrictive.1,6,12 Local injection is used to perform sphincterotomies in the treatment of fissures, to excise hypertrophic anal papillae and skin tags, to treat short fistulous tracts, and to treat perianal hematoma. Contraindications include local septic conditions, the patients anxiety, the patients insufficient compliance, and the prolonged time required for the procedure. If necessary, the patient can be given premedication 30 min to 1 h before the procedure: 5-10 mg diazepam administered orally is very effective. The skin is cleaned and disinfected with an antiseptic solution. The anesthetic solution is injected at first subdermally and then submucosally around the lesion to be treated with a continuous motion of the needle or frequent aspiration to prevent intravascular injection. Injection within the muscle may be avoided depending on the depth of the lesion. One should never inject near a septic lesion to avoid bacteremia. The only septic condition where local anesthesia is possible is an abscess requiring emergency drainage without any surgical exploration. We should only infiltrate the place where the knife will be pushed to evacuate the pus. Table 5-4 Complete resuscitation equipment (suction, mask and intubation set, O2, resuscitative drugs) must always be available Maximal dosage of the local anesthetic drugs must not be exceeded Premedication is not reliable in preventing systemic toxic reactions Patients have to be observed carefully after completion of the injection Any complication should be correctly evaluated Any type of complication must be expected and, if necessary, treated Any type of complication or reaction should not be over- or undertreated 168 5 ❑ Anesthesia in Proctology POSTERIOR PERINEAL BLOCK Posterior perineal block is a technique based on precise knowledge of the anatomy of perineal nerves (Fig. 5-1). We use routinely following mixture: 60 ml 0,5% lidocaine, 10-15 units POR 8 (Ornithine - 8 vasopressine) 6 ml bicarbonate 8,4%. i e d TH b JI( h a a UP .R Ischion c e h b NA g f i .R c NA T j AK j DR Ischion k UP f k H ) Symphyse pubienne d g Muscle grand fessier Coccyx sacrum DR Fig. 5-1. Innervation of the perineum: a, ano-coccygeal nerve; b, cutaneous bundle of the pudendal plexus giving a gluteal nerve and an perineal nerve; c, three branches of posterior femoro-cutaneous nerve; d, gluteal branch; e, posterior perineal branch; f, anterior perineal branch); g, four branches of the pudendal nerve; h, hemorroïdal nerve or anal nerve or inferior rectal nerve; i, anterior sphincteric nerve; j, dorsal penis or clitoris nerve; k, perineal nerve. After subdermal infiltration at two sites (Fig. 5-2A), anterior and posterior but outsite the rima ani, the anococcygeal ligament is deeply infiltrated (Fig. 5-2B) with 2 - 5 ml anesthetic solution; through the previously dermal papula 8-10 ml solution are injected into both ischiorectal spaces when withdrawing the needle which is oriented at 45° cranially and 45° laterally (Fig. 5-2C). This allows anesthesia of the deep nerve endings. Through the anterior puncture in front of the anus, 5-10 ml solution are then infiltrated subdermally on each side (Fig. 5-2D) 169 5 ❑ Anesthesia in Proctology B NA T H ) A D NA TH JI( DR .R UP AK C DR .R UP Fig. 5-2. Technique of local infiltration. A. Anterior and posterior subdermal infiltration. B. Infiltration of the anococcygeal ligament. C. Infiltration of both ischiorectal spaces. D. Subdermal infiltration at the level of the rima ani. at the level of the rima ani to secure analgesia of the more superficial nerve endings. The total amount injected is less than 60 ml. This type of anesthesia is our usual one to perform hemorrhoidectomies. It allows a short hospital stay, a dry operative field, prolonged anesthesia with a low rate of bladder retention. If used on an outpatient, he or she should not leave the hospital until he or she has completely recovered from the premedication and has passed urine. CAUDAL BLOCK Caudal block is a type of epidural block.12,14 With the patient in a prone jackknife position, 15-20 ml 2% lidocaine with epinephrine or 0.25% bupivacaine with epinephrine are injected into the sacral canal through the sacrococoygeal space after ensuring by suction that no blood or cerebrospinal fluid can be 170 5 ❑ Anesthesia in Proctology AK NA T H ) withdrawn. Immediately after injection, the patient is turned on the back side and put in anti-Trendelenburg position to ensure sacral distribution of the drug. This technique should not be used in patients with inadequate coagulation as in case of hepatic insufficiency. Contraindications to such an anesthesia are constituted by extensive septic lesions, sacral dermoid cysts and sequellae of traumatic lesions of the sacrum and coccyx. Success rate of this technique is about 90-95%. Two major complications are feared: 1. Puncture of the dura mater with injection of the drug in the cerebro-spinal fluid which results in a total spinal anesthesia, respiratory insufficiency and death. 2. Too rapid injection or injection within the venous plexus resulting in high systemic toxicity. SIDE EFFECTS AND COMPLICATIONS CONCLUSIONS .R UP NA TH JI( DR .R UP Further to the complications related to the toxicity of drugs used, anesthesia in proctological surgery may induce urinary retention. Zaheer15,19 in an extensive study noticed bladder retention rates ranging from 0 to 43% in relation to the type of procedure and type of anesthesia (Table 5-5). The lowest rate was observed with local anesthesia and the highest with caudal anesthesia. In our experience,5,12 the posterior perineal block results in a urinary retention rate of 0,5%. Such a low rate could be achieved because several operative conditions were strictly observed: 1. Empty bladder before surgery. 2. No intravenous infusion. 3. No oral fluid intake before first miction. Such a law rate allows ambulatory surgery even for hemorrhoidectomies. DR Most surgical procedure involving the anal canal can be performed in local anesthesia, posterior perineal block and caudal block. Successful anesthesia can be achieved by the surgeon himself if he knows the exact anatomy of perineal Table 5-5. Urinary retention and type of anesthesia19 General anesthesia Spinal anesthesia Local anesthesia Caudal anesthesia Hemorrhoidectomies Sphincterotomies fistulotomies incision-drainage 37 % 36 % 17 % 43 % 6% 8% 0% 3% 171 5 ❑ Anesthesia in Proctology innervating, if he applies a precise infiltration technique and uses well selected drugs at a correct dosage. REFERENCES DR .R UP NA TH JI( DR .R UP AK NA T H ) 1. Auberger HG. Praktische Lokalanästhesie: ein Kompendium Thieme, Stuttgart, 1969. 2. Barry BA. Die Lokalanästhesie bei ambulanten Eingriffen. In Kinoch HG, Hager TH, Frank WL (Eds.): Aktuelle Koloproktologie, Vol. 1. Nymphenburg, Munich, 1985. 3. Bonica JJ, Akamatsu TJ, Berges PU et al. Circulatory effects of peridural block, Vol. II: effects of epinephrine. Anesthesiology 1971;34:514522. 4. Clery AP. Local anesthesia containing hyaluronidase and adrenaline for anorectal surgery experiences with 576 operations. Proc R Soc Med 1973;66:680681. 5. Cuccia G, Forster A and Marti M-C. Positioning and anesthesia for anorectal surgery. In Marti M-C, Givel J-C: Surgical management of anorectal and colonic diseases. Berlin-Heidelberg: Springer-Verlag, 1998, pp 113120. 6. De Jong RH. Toxic effects of local anesthetics. JAMA 1978;239:11661168. 7. Guinard JP, Carpenter RL, Owens BD et al. Comparison between ropivacaine and bupivacaine after subcutaneous injection in pigs cutaneous blood flow and surgical bleeding. Reg Anesth 1991;16:268271. 8. Kam PCA and Tay TM. The pharmacology of ornipressin (POR-8): a local vasoconstrictor used in surgery. European Journal of Anesthesiology 1998;15:133139. 9. Kratzer GL. Local anesthesia in anorectal surgery. Dis Colon Rectum 1965;8:441446. 10. McKay W, Morris R, Mushlin P. Sodium bicarbonate attenuates pain on skin infiltration with lidocaine, with or without epinephrine. Anesth Analg 1987;66:572574. 11. Marti MC Froidevaux A, Rifat K Préparatin préopératoire et choix de lanesthésie en proctologie. Med Hyg 1977;35:23342338. 12. Marti MC. Anesthésie loco-régionale en chirurgie proctologique Ann Chir 1993;47:250255. 13. Moore DC, Bridenbaugh LD, Thompson GE et al. Bupivacaine: a review of 11080 cases Anesth Analg 1978;57:4253. 14. Moore DC Regional block, 4th ed. Thomas, Springfield. 1981 15. Pertek JP, Haberer JP Effets de lanesthésie sur la miction et rétention aiguë durine postopératoire. Ann Fr Anesth Réanim 1995;14:340351. 16. Pittet JF Pharmacologie et toxicité des anesthésiques locaux. Schweiz Rundsch Med Prax 1987;76:865871. 17. Scott DB Maximum recommended doses of local anaesthetic drugs Br J Anaesth 1989;62:373374. 18. Watson D Hyaluronidase Br J Anaesth 1993;71:422425. 19. Zaheer S et al. Urinary retention after operations for benign anorectal disease Dis Colon Rectum 1998;41:696704.