Effectiveness of Analgesia of Combined Femoral and Sciatic Blocks Versus Epidural Anesthesia for Lower Limb Amputations

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1 Med. J. Cairo Univ., Vol. 84, No. 2, June: , Effectiveness of Analgesia of Combined Femoral and Sciatic Blocks Versus Epidural Anesthesia for Lower Limb Amputations TAMER I. ROUK, M.Sc. and TAMER M. KHEIR, M.D. The Department of Anesthesiology, Surgical ICU and Pain Management, Faculty of Medicine, Cairo University Abstract Background: Peripheral neural blockade appears to provide effective analgesia compared with central neuraxial techniques. We compared both techniques as an anesthesia plan for unilateral lower limb amputations. Aim of Work: Comparing of onset of sensory and motor block sufficient to perform the surgical procedure. Assessment of duration of post-operative analgesia using Visual Analogue Score (VAS), incidence of intra operative and post-operative complications, and risk of failure: Complete failure, patchy or single block only. Patients and Methods: Eighty patients, undergoing unilateral lower limb amputations were prospectively randomized to receive either combined femoral and sciatic nerve blocks (single shot each) or lumbar epidural anesthesia. Combined femoral sciatic block group (n=40) received isobaric bupivacaine 0.375% (femoral 20ml and sciatic 20ml) with nerve stimulator guidance. While epidural group (n=40) received isobaric bupivacaine 0.375% using loss of resistance to air technique for space detection then 5-mL aliquots were given to attain a sensory level at T10 which is adequate for lower limb amputation surgery. Block onset time, visual analogue pain scores and first time to ask for analgesia were recorded postoperatively and perioperative complications were also assessed. Results: The onset of epidural block was significantly shorter. However, statistically and clinically significant more prolonged post-operative analgesia was noted with femoralsciatic block group. There was no major difference in perioperative complication within first 24h, apart from shivering with epidural group and non-significant higher failure rate with femoral-sciatic block group. Conclusion: The use of combined femoral-sciatic nerve block is superior in prolonged post-operative analgesia to conventional epidural analgesia in patients undergoing unilateral lower limb amputations. However, block onset is faster and success rate is better in epidural block. Key Words: Femoral-sciatic block Nerve stimulator Epidural Infrainguinal amputations. Correspondence to: Dr. Tamer I. Rouk, The Department of Anesthesiology, Surgical ICU and Pain Management, Faculty of Medicine, Cairo University Introduction PATIENTS with peripheral vascular disease are at increased risk of complications both related to the nature of the surgical procedure and to their co-morbidity. Most vascular surgical patients have advanced atherosclerotic disease and a variety of medical problems (as diabetes, hypertension and ischemic heart disease) complicating the perioperative management. Pan vascular disease should be assumed in all patients presenting for infrainguinal vascular surgery [1]. General anesthesia is not preferred for these patients, because both postoperative anesthesia-related pulmonary complications and confusion can interfere with recovery and timely discharge [2]. Regional anesthetic techniques are chosen according to risk/benefit analysis of each patient, with proven benefits as analgesia and extension of anesthetic blockade in case of reexploration [1]. For these reasons, the preference of regional anesthesia, including either neuraxial blocks or multiple peripheral nerve blocks, has increased, as these blocks ensure adequate intraoperative and postoperative analgesia. Among these regional anesthesia techniques on the lower limb, peripheral nerve blocks are gaining popularity because they provides effective analgesia and anesthesia with potentially fewer complications and side effects than neuraxial blocks [2]. Regional blocks of the lower limb using a combination of a sciatic nerve block with a femoral nerve block is a good alternative technique to the conventional neuraxial (spinal or epidural) anesthesia, which may be problematic with septic, cardiologically unstable or anti-coagulated patients, again spinal/epidural anesthesia may drop the blood pressure further [3]. The present study was attempted to demonstrate if the technique of combined femoral and sciatic 317

2 318 Effectiveness of Analgesia of Combined Femoral & Sciatic Blocks nerve blocks is superior or equal to the conventional epidural anesthesia for unilateral lower limb amputations. Material and Methods This study was performed in surgical operative suite in Kasr Al-Ainy Hospitals, Cairo University after approval of Departmental Ethical Committee between April 2012 and February Patients were asked to give an informed written consent when they were willing to take part in the study and after explanation of the possible advantages and side effects. The population included 80 patients, aged years, ASA (American Society of Anesthesiology) physical status I, II or III, scheduled for unilateral lower limb amputations (below knee amputation, above knee amputation, and trans-metatarsal amputation). Patients were excluded if they refused consent, ASA classification >III, history of local anesthetic allergy, infection at site of injection, coagulopathy (INR >1.5, Platelets less than /mm), peripheral neuropathy, patients with confusion or delirium (uncooperative with lack of communication) and patients with previous vascular anastomosis at site of femoral block injection. All patients underwent systematic preoperative assessment prior to the scheduled date of surgical intervention. Patients were instructed to fast for 6 hours before surgery. All patients were trained on the use of visual analogue pain score, where zero corresponds to no pain and 100 is indicative of the worst unbearable pain. On arrival to operative suite, and after inserting IV line in the preparation room, midazolam 1mg IV then 0.5mg increments was given slowly every 2 minutes till patient was sedated but responding to verbal stimuli. Standard monitors were applied before the regional techniques, with continuous ECG, non-invasive blood pressure and pulse oximetry (SpO 2 ). Patients were preloaded by Ringer's solution 250ml over 10min., with attention to SpO 2 (not less than 92% on room air) and basal chest auscultation. O 2 mask was applied immediately after performing blocks. Patients were randomized into two groups of 40 patients each. received combined femoral and sciatic nerve blocks (single shot each) with insulated 22 gauge regional needles (Stimuplex, Braun) attached to a peripheral nerve stimulator ((Life-TechTM, Model ES400, Stafford, TX, USA). The regional nerve blocks were performed using isobaric bupivacaine 0.375%. The sciatic nerve block was performed using the posterior approach of Labat, the patient was positioned laterally, with a slight forward tilt. The foot on the side to be blocked was positioned over the dependent leg so that twitches of the foot or toes easily noted. A line between the upper tip of greater trochanter and posterior superior iliac spine was connected and divided in half. A second line is drawn between the greater trochanter and the sacral hiatus. A perpendicular line is drawn from the midpoint of the original line and extended about 4-5cm in the caudad direction, until intersecting the second line at a point, that is marked as the needle entry point, an insulated 100-mm shortbevel needle was advanced at this level, and the sciatic nerve was located by a nerve stimulator (dorsiflexion or extension) and blocked by 20mL of the bupivacaine solution. Femoral nerve block was performed by using the technique described by Winnie et al., [4], where the patient was placed in supine position, a line was drawn between the anterior superior iliac spine and the pubic tubercle to identify the inguinal ligament, the femoral artery was marked, the same insulated needle was advanced lateral to the artery, and the femoral nerve was located by a nerve stimulator (quadriceps contraction) and blocked by 20mL of the bupivacaine solution. Successful anesthesia was indicated by loss of pain sensation (in response to pinprick test) after 20-30min. in the feet, leg, knee and lower two thirds of the thigh, and motor power loss in the whole limb. In case of failure of the block (after sensory testing within 20-30min.), general anesthesia was induced as an alternative plan, with paying attention to patient co-morbidities, as ischemic heart disease. Induction with IV propofol 2mg/kg with fentanyl 2 microgram/kg, and atracurium 0.5mg/kg, then smooth intubation and ventilation as usual, with inhalational maintenance of anesthesia. received lumbar epidural anesthesia, in the sitting position, Tuohy needle (Braun, 18- gauge) was inserted in L4-5, or L5-S 1 space, with loss of resistance to air technique for space detection, then the catheter (Braun, 20-gauge) was inserted in the epidural space, then advanced approximately 4-6cm cephalic, and fixed by tapes on the back. The epidural block was activated by bupivacaine 0.375% in 20ml total volume, and was given in 5-mL aliquots to attain a sensory level at T 10 which is adequate for surgery. Successful anesthesia is indicated by loss of pain sensation (in response to pinprick test) up to the level of the umbilicus and motor power loss in both lower limbs (failure to elevate the leg off the table). Top up injections 5ml of the same preparation were given every 40-45min. to maintain anesthesia. At the end of surgery the epidural catheter was re-

3 Tamer I. Rouk & Tamer M. Kheir 319 moved carefully, a sterile piece of gauze was applied and taped on the puncture site. Intra-operatively, onset of sensory and motor block sufficient to start the surgical procedure was recorded, with maximum 30min. failure to attain analgesia at this time is considered failure, and general anesthesia was induced. Also patients were closely monitored to maintain hemodynamics. Complications as dysrhythmias, shivering, nausea and vomiting, itching or local anesthetic toxicity were observed. Post-operatively, patients were discharged to the recovery room for 15min., where Visual Analogue Scale (VAS) assessment of pain was done, then patient was transferred to the ward (or to intensive care unit ICU if indicated), then patients were followed-up where VAS was done 6, 12 and 24 hours after discharge from the recovery. First time the patient asked for analgesia was recorded, and any further complication (back pain, headache, femoral or gluteal pain and swelling suspecting hematoma) were observed within the first 24 hours postoperatively. Statistical analysis: Obtained data were presented as mean ± SD, ranges, numbers and percentages as appropriate. Nominal variables were analyzed using Chi-squared ( χ 2 ) test or Fischer exact test as appropriate. Continuous variables were analyzed using unpaired Student s t-test or univariate two-group repeated measures mixed-design analysis of variance (ANOVA) with post hoc Dunnett's test as appropriate. Nominal and non-normally distributed variables were analyzed using Mann- Whitney U-test. Statistical calculations were performed using Microsoft Office Excel 2007 and SPSS (Version 17, 2008). p-value <0.05 was considered statistically significant. Results Eighty patients were enrolled in this study after signing informed consent; they were randomly allocated into two groups: had combined femoral and sciatic nerve block (nerve stimulator guided) (40 patients), and had epidural anesthesia (40 patients). Three patients were excluded from the study after randomization due to failure to assess postoperative pain, because they were transferred to ICU while intubated and sedated due to development of septic shock (moist gangrene) intraoperatively. All data analyses were performed after exclusion of these cases. So were 39 cases and were 38 cases, total number was 77 cases. Demographic data (age, gender, and smok- ing) showed no significant difference between groups (Table 1). Table (1): Demographic data of patients within groups. Group A Group B Total p- value Age (years): 63 (±9.9) 58.4 (± 10.8) 0.05 Mean (±SD) Males: 23 (59%) 20 (52.6%) Females: 16 (41%) 18 (47.4%) Smokers: 15 (38.5%) 13 (34.2%) Distribution of medical diseases (diabetes, hypertension, renal impairment, hepatic impairment, bronchial asthma, ischemic heart disease and stroke) is shown in (Table 2), with count and % within group for every disease. Table (2): Count and percentage of medical diseases in each group. Medical co-morbidities Total count (% within all cases) Diabetes mellitus 25 (64.1 %) 24 (63.2%) 49 (63%) Hypertension 22 (56.4%) 15 (39.5%) 37 (48%) Renal impairment 2 (5.1%) 0 (0%) 2 (2.6%) Hepatic impairment 0 (0%) 2 (5.3%) 2 (2.6%) Bronchial asthma 2 (5.1%) 2 (5.3%) 4 (5.2%) Ischemic heart disease 9 (23.1) 5 (13.2%) 14 (18.2%) Stroke 2 (5.1%) 2 (5.3%) 4 (5.2%) ASA classification of patients was random as shown in (Table 3). Table (3): ASA classification of patients within each group. ASA I 3 (7.7%) 0 (0%) 3 Total ASA II 21 (53.8%) 18 (47.4%) 39 ASA III 15 (38.5%) 20 (52.6%) 35 Total 39 (100%) 38 (100%) 77 After performing the regional block in both groups, the mean time ( ±SD) of onset of surgical anesthesia varied significantly between the groups, it was 22.8 (±4.8) min for, and 13.8 ( ±3.5) min. for, with p.value <0.001, as shown in (Table 4).

4 320 Effectiveness of Analgesia of Combined Femoral & Sciatic Blocks Table (4): Comparing time of onset of surgical anesthesia between both groups, with p.value. Table (6): Count and (% of complications within each group, with p.value. Time in minutes ±SD min. p-value Onset of surgical anesthesia in 22.8 (±4.8) 13.8 (±3.5) <0.001 minutes: Mean (± SD) Intra-operatively, tracing of heart rate and blood pressure showed no statistical difference between both groups throughout the operative time. Visual Analogue Scale (VAS) assessment in the recovery room, and then 6, 12 and 24 hours later, showed significant better analgesia in group A at 6 hours, with p.value <0.001, but not that significant at other times of assessment, as shown in (Table 5). Table (5): Visual Analogue Scale (VAS) assessment between both groups at different times, with p.value. Median (Range) Median (Range) min. p- value VAS at recovery 0 (0-100) 0 (0-80) VAS after 6H 30 (0-100) 70 (30-100) <0.001 VAS after 12H 80 (0-100) 75 (30-100) Vas after 24H 80 (40-100) 70 (10-100) When comparing 1 st time to ask for analgesia after the operation, a mean ( ±SD) of (± 159.2) min in, in comparison to 33.1 ( ± 16.7) min in was found Fig. (1). This was both clinically and statistically significant (p.value <0.001). Fig. (1): Comparing 1 st time to ask for post-operative analgesia in minutes. No local anesthetic toxicity, dysrhythmias, allergy, hypertension, itching or back pains were recorded in all patients within the observation time (24h). A small number of peri-operative complications included significant difference with shivering only between groups, and non-significant difference in hypotension, failure (and induction of general anesthesia), bradycardia, headache, nausea and vomiting, and hematoma formation (Table 6). p- value Hypotension 4 (10.3%) 10 (26.3%) 0.68 Failure (with 6 (15.4%) 2 (5.3%) 0.14 induction of GA) Bradycardia 0 (0%) 1 (2.6%) 0.30 Shivering 0 (0%) 7 (18.4%) Headache 0 (0%) 1 (2.6%) 0.30 Nausea and vomiting 0 (0%) 1 (2.6%) 0.30 Hematoma formation 1 (2.6%) 0 (0%) 0.32 Discussion The present study showed that combined femoral-sciatic block for unilateral infrainguinal amputations is an adequate anesthesia plan when compared with conventional lumbar epidural anesthesia. It provided more prolonged post-operative analgesia, but with less success rate and more time for onset than the conventional epidural anesthesia. Nerve stimulator was selected as a method of femoral and sciatic nerves localization in our study as well as in many other studies [2,3,5-7]. In contrary to the more expensive and advanced U/S used in Al-Zahrani et al., study [8]. The number of patients in the present study was 80 cases divided into 2 groups, only Horasanli et al., 2010 [2] used the same number of cases, while other studies were done on 60 patients or less. There was some clinical heterogeneity among the studies. For example, Al-Zahrani et al., [8] used U/S guided continuous femoral nerve block combined with sciatic nerve block versus epidurals, Papiol et al., [9] used epidural analgesia versus femoral or femoral-sciatic nerve blocks, Barrington et al., 2005 [10] compared continuous femoral nerve blockade or epidural analgesia (both associated with spinal anesthesia). There was also variation in the drug, additives, and doses used. The aim of the anesthetic techniques in our study was more satisfactory analgesia post-operatively. The onset of regional blocks adequate for surgery in the present study was 22.8 ( ±4.8) min in femoral-sciatic group and 13.8 (±3.5) min in epidural group, which was statistically significant. This was in contrary to Davies et al., 2004 study [6], in which time (range) was 13 (8-18.5) min in epidural group and 12.5 ( ) min in nerve block group, which was not significant. This may

5 Tamer I. Rouk & Tamer M. Kheir 321 be related to the different volume used (bupivacaine 0.375% in a volume of 30ml for the femoral component and 25ml for the sciatic component). A significantly more prolonged post-operative analgesia, (± 159.2) min., was noticed in combined femoral-sciatic block group, in comparison to 33.1 (± 16.7) in epidural group, although it is a single shot nerve block and not a continuous infusion. This was important as the impact of the former technique on the geriatric population was less postoperative pain complications, mainly cardiac morbidity and hemodynamic stability. This long analgesia duration is consistent with Horasanli et al., [2] who found that the time to first analgesic requirement was significantly delayed in the combined lumber plexus-sciatic block group with median (range): 360 ( ) min., than in the epidural group: 240 ( ) min. Papiol et al., [9] recorded that pain intensity was significantly less, in the first 24 hours after knee surgery, for patients who received a femoral-sciatic nerve block. Baddoo [3] had similar results, when he did combined femoral-sciatic or combined femoralparavertebral block on ten cases of emergency lower limb amputations, and he found that the time interval between the end of surgery and the time to the first dose of rescue analgesic in all cases, ranged between 5hrs and 30.5hrs with a mean of 12.5hrs which is important for patient satisfaction. However Al-Zahrani et al., [8] stated no statistically significant difference between the epidural and continuous femoral block groups in pain scores (NRS) during the first 72 hours postoperatively, and postoperative morphine consumption was found not to be statistically different between the two groups. Zaric et al., 2006 [7] stated that the efficacy of analgesia and duration of hospitalization were comparable in both combined femoral-sciatic and epidural groups after total knee surgery. Also Davies et al., [6] results were contrary to a significant difference in analgesia, they found that: 23 of 29 patients (after unilateral knee replacement surgery) reported no pain on attempted knee movement in epidural group, compared with 16 of 30 patients in the combined femoral-sciatic nerve block group (not significant). No major complications (local anesthetic toxicity, dysrhythmias, angina, myocardial infarction, allergy, back pain or itching) were recorded in the present study, and also no mortality was present. Only 7 cases (18.4%) of shivering occurred in epidural group which was statistically significant but clinically non significant, and hypotension (with need for ephedrine bolus) in 4 cases (10.3%) of femoral-sciatic block group, and 10 cases (26.3%) of epidural group, this was statistically not significant, but may be clinically significant in our geriatric population. In Yazigi et al., 2005 study [5], two of 25 patients (8%) required small doses of ephedrine (6 and 9mg) during surgery. A small incidence of failure to achieve adequate anesthesia for surgery (with need for induction of general anesthesia) was recorded in 6 cases (15.4%) of femoral-sciatic group, and 2 cases (5.3%) of epidural group which was statistically not significant. Failed cases may be attributed to individual skill in block performance, and may be decreased by using U/S for performing the nerve blocks in future studies. Al-Zahrani et al., [8] reported failure of catheter placement in two of 28 cases (7%) of epidural group and one in 28 cases (3.5%) of combined femoral-sciatic group, inspite using U/S guidance for nerve blocks. In Horasanli et al., 2010 study [2], failure in one patient (2.5%) of the epidural group and three patients (7.5%) of the combined lumber plexus-sciatic block group occurred and required general anesthesia. Other rare incidents in the present study were: One case of headache (2.6%), one case of bradycardia (2.6%) and one case of nausea and vomiting (2.6%) were in epidural group and were properly managed. While only one case of small femoral hematoma (2.6%) occurred in femoral-sciatic group and managed conservatively. All these were statistically non significant. Zaric et al., [7] observed statistically significant urinary retention in the epidural group on the day of surgery and the first postoperative day. Future thoughts: Further studies concerning the same comparison groups may be done but using the more accurate but expensive ultrasound guidance for nerve blocks, to avoid the high failure rate and prolonged technique time in the present study. Also different local anesthetic preparation (e.g. adding opioids) may be used for better analgesia efficacy and duration. And more parameters can be assessed: Patient satisfaction rate, change in morphine consumption rate and serum level of stress hormones. Conclusion: Combined femoral-sciatic nerve blocks can effectively be used for unilateral infrainguinal amputations, providing good postoperative analge-

6 322 Effectiveness of Analgesia of Combined Femoral & Sciatic Blocks sia for long durations when compared to conventional lumbar epidural anesthesia. The introduction of ultrasound guided regional anesthesia is a promising advance, increasing the success rate and safety of these peripheral nerve blocks. References 1- HASSETT P. and IOHOM G.: Anaesthesia for infrainguinal vascular surgery. J. Rom. Anest. Terap. Int., 20: pp. 43-8, HORASANLI E., GAMLI M., PALA Y., EROL M., SA- HIN F. and DIKMEN B.: A comparison of epidural anesthesia and lumbar plexus-sciatic nerve blocks for knee surgery. Clinics, 65 (1): pp , BADDOO H.K.: A preliminary report on the use of peripheral nerve blocks for lower limb amputations. Ghana Med. J., 43: 24-8, pp. 24-8, WINNIE A.P., RAMAMURTHY S. and DURRANI Z.: The inguinal paravascular technique of lumbar plexus anesthesia: The 3-in-1 block. Anesth. Analg., 52: , YAZIGI A., MADI-GEBARA S., HADDAD F., HAYECK G. and TABET G.: Combined Sciatic and Femoral Nerve Blocks for Infrainguinal Arterial Bypass Surgery: A Case Series. Journal of Cardiothoracic and Vascular Anesthesia, 19 (2): pp , DAVIES A.F., SEGAR E.P., MURDOCH J., WRIGHT D.E. and WILSON I.H.: Epidural infusion or combined femoral and sciatic nerve blocks as perioperative analgesia for knee arthroplasty. British Journal of Anaesthesia, 93 (3): pp , ZARIC D., BOYSEN K., CHRISTIANSEN C., CHRIS- TIANSEN J., STEPHENSEN S. and CHRISTENSEN B.: A Comparison of Epidural Analgesia With Combined Continuous Femoral-Sciatic Nerve Blocks After Total Knee Replacement. Anesth. Analg., 102: pp , AL-ZAHRANI T., DOAIS K.S., ALJASSIR F., ALSHAYGY I., ALBISHI W. and TERKAWI A.S.: Randomized Clinical Trial of Continuous Femoral Nerve Block Combined with Sciatic Nerve Block Versus Epidural Analgesia for Unilateral Total Knee Arthroplasty. The Journal of Arthroplasty, 30: pp , PAPIOL S., MONSEGUR C.J., VIVES B.E., CESPE- DOSA G.A., VILARNAU B.R., PÉREZ M.A. and VILLÉN E.F.: Epidural analgesia versus femoral or femoral-sciatic nerve block after total knee replacement: Comparison of efficacy and safety. Rev. Esp. Anestesiol. Reanim., 56 (1): pp , BARRINGTON M.J., OLIVE D., LOW K., SCOTT D.A., BRITTAIN J. and CHOONG P.: Continuous Femoral Nerve Blockade or Epidural Analgesia After Total Knee Replacement, A Prospective Randomized Controlled Trial. Anesth. Analg., 101: pp , 2005.

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