Can Femoral Nerve Block Reduce Analgesic Requirement After Surgery for Fractured Femur?

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1 Can Femoral Nerve Block Reduce Analgesic Requirement After Surgery for Fractured Femur? Manee Raksakietisak M.D., FRCA* Arissara Iamaroon M.D.,* Pathom Halilamien M.D.,* Kwankamol Boonsararuxsapong M.D.,* Jitaporn Hongsawad M.D.* àõ : Femoral nerve block «μâõß âª«à ß ºà μ Ÿ μâπ À âà Õ à π μ» Ï æ..,* Õ» Õ Ë Õ ÿ æ..,* ª Àå æ..,* «ÿ» æß»å æ..,* μ æ Àß å «Ï æ..* * «««æ» μ å» æ À «À «μ ÿª ß å : æ ËÕ» º ß ª«À ß ºà μ Õß Ë âπª femoral πºÿâªé«ë Ÿ μâπ À Ë ºà μ «: àߺÿâªé«ë ºà μ μ Èß μà π«2549 ß æƒ 2551 ÿà ªìπ 2 ÿà ÿà 25 π ÿà Ë 1 â spinal block â«0.5% isobaric bupivacaine æ ß Õ à ß «à«π ÿà Ë 2 â femoral nerve block â«0.33% bupivacaine π«π 30. à«spinal block ºŸâªÉ«ÿ â ⪫æ μ - Õ 1 ÿ 6 Ë«ß pethidine 50. â â ÿ 4 Ë«ß â â à «ª«4 ππ ª π à «ª«ÿ 4 Ë«ß π 24 Ë«ß º» : ºŸâªÉ«à«π À à ºà μ hemiarthroplasty dynamic hip screw àæ «μ μà ß À«à ß ÿà Ë «Ë«ª ÕߺŸâªÉ««ª«ª ⪫ëºÿâªé«â ÿª : Ë âπª femoral æ ß 1 Èß àõπ ºà μ à «μâõß âª«à ß ºà μ Ÿ μâπ À : Ë âπª femoral Ÿ μâπ À º ß ª«Thai J Anesthesiology 2009 ; 35(2) : Femoral nerve block or fascia iliaca compartment block has been used for pre-operative analgesia for fractured femur in several settings such as prehospital, 1 emergency room, 2-5 ward 6 and pre-positioning for spinal block. 7 However after the fracture has been fixed, the pain usually becomes less severe and it has *Department of Anesthesiology, Siriraj Hospital, Mahidol University, Bangkok Thailand 83

2 not been clear whether or not the single shot femoral nerve block has some benefits in the postoperative period. We studied the analgesic effect of a femoral nerve block combined with spinal block, compared with spinal block alone, in patients undergoing surgery for fractured femur. Methods After obtaining institutional approval and written informed consent, from December 2006-May 2008 (18 months), 56 ASA physical status I-III patients with fractured femur were prospectively included in this study. The other inclusion criteria were adulthood (age > 18 years and < 80 years) and appropriate bodyweight (> 50 kg and BMI < 30 kg/m 2 ) and the anaesthetists chose spinal block as an anesthetic technique. Exclusion criteria were hemorrhagic diathesis, peripheral neuropathy, allergy to local anesthetics, pain medications being used in this protocol, mental disorders or communication failure and multiple fractures. Light premedication such as oral benzodiazepines (midazolam mg or diazepam 2-5) can be given. The patients were allocated randomly by computer-generated number into 2 groups. Group I, the control group, received only spinal block with 0.5% isobaric bupivacaine 2-4 ml, and group II, the femoral nerve block (FNB) group, received an extra femoral nerve block guided by peripheral nerve stimulator (Stimuplex ; B Braun). After arrival in the induction area, all patients were monitored with ECG, pulse oximeter and NIBP, and intravenous fluid (balanced salt solution) was given. In the FNB group, the insulated 50 mm 22 G needle was introduced 1 cm laterally to the femoral artery and just below the inguinal ligament. When the current ma elicited quadriceps contraction, 0.33% bupivacaine 30 ml (0.5% bupivacaine 20 ml+ NSS 10 ml) was injected incrementally. After 15 minutes, the paresthesia was tested to ensure the success of the femoral nerve block. Patients were not blinded to group allocation because we considered placebo injection unacceptable. All patients received a small dose of intravenous fentanyl (25-75 mcg) for pain relief during positioning and were placed to lateral position with the fracture site up. The spinal block was performed in either the midline or paramedian approach at the L2-3 or L3-4 level and 0.5% isobaric bupivacaine was injected, ml according to anaesthetists preference (blinded to patient s group). Recorded data included patientsí demographic, operative data, perioperative complications, pain scores and total dose of analgesic requirement. Postoperative pain medication included oral paracetamol 1 g every 6 hours for 24 hours and then as required, intramuscular pethidine 50 mg for pain scores were 4 every 4 hours and intravenous rofecoxib 40 mg every 12 hours as a third pain relief drug if the patient still had moderate to severe pain despite receiving paracetamol and pethidine. Postoperative pain scores were assessed every 4 hours by the ward nurses who were blinded to the intervention. The numeric rating scale (0-10) was used because it was easier for elderly patients. If the patient was asleep, no pain scores were recorded. Data were analyzed using SPSS 13.0 software package. Parametric variables were described as mean ± SD ; qualitative variables were described as number (percent) and as median (range). Studentís t-test, Chisquare test or Fisher exact test or Mann-Whitney U test were used as appropriate to compare the two groups. The repeated measures were used for comparing postoperative pain scores. P < 0.05 was considered statistically significant. Sample size calculation was estimated from the 50% reduction in postoperative analgesic requirement (pethidine from 100 mg to 50 mg) and SD = 70 (from pilot study), α = 0.05 and β = 0.20, one sided test and a minimum 25 patients per group would be required. N = 2 (Zα + Zβ) 2 (σ/μ 1 - μ 2 ) 2 84 «ªï Ë 35 Ë 2 π- ÿπ π 2552

3 = 2 ( ) 2 (70/100-50) 2 = 25 An extra 3 patients per group (10%) were also included for dropout so 28 patients per group would be appropriate. Results During the study period there were more than 300 patients with fractured femur but only 56 patients were included in this study. Most of the patients were excluded due to exclusion criteria such as advanced age (> 80 year old), communication failure, multiple fractures, use of general anesthesia, contraindication for regional anesthesia and patient s refusal. There were three patients in each group who dropped out from this study. In control group, the reasons were failed subarachnoid block due to scoliosis in one patient and two patients who receiving non-protocol pain medications. In the study group, the reasons were failed femoral nerve block (1), acute delirium (1), received other pain medication (1). Demographic data (table 1) were not significantly different between two groups although time from trauma to surgery was longer in the control group (p = Table 1 Demographic data Group I (control) Group II (FNB) p-value N = 25 N = 25 Age (years) 70.4 (8.0) 67.4 (15.5) 0.39 Sex (M/F) 11/14 8/ Weight (kilograms) 57.6 (10.0) 57.0 (8.2) 0.82 Time from trauma to surgery (days) 11 [5,19] 6 [5,10] 0.10 Fracture site 0.09 neck intertrochanteric 13 6 shaft 1 4 other 1 0 ASA physical status I/II/III 2/20/3 6/17/ Underlying diseases DM 7 8 HT 8 12 IHD 0 1 History of CVA 2 2 CRF 1 0 COPD/asthma/TB 5 1 Others (anemia, History of malignancy, Parkinson, depression, etc) Data were expressed as mean (SD) or median [IQR] or number Vol. 35, No.2, April-June 2009 Thai Journal of Anesthesiology 85

4 Table 2 Intraoperative data Group I (control) Group II (FNB) p-value N = 25 N = 25 Dose of 0.5% isobaric bupivacaine (ml) 2.9 (0.3) 2.9 (0.4) 0.91 Anesthetic level (thoracic) T8 [6,10] T10 [6,10] 0.97 Operation Hemiarthroplasty Dynamic hip screw 12 7 Others (K-nail, etc) 3 6 Fluid administered Crystalloid (ml) 1,426 (451) 1,419 (506) 0.96 Colloid (1 unit = 500 ml) 0 [0, 0] 0 [0, 0] 0.37 Blood (unit) 0 [0, 0] 0 [0, 0] 0.25 Estimated blood loss (ml) 235 (201) 199 (142) 0.48 Operative time (minutes) 97 (36) 95 (38) 0.81 Complication Hypotension Bradycardia 0 1 Others* 4 0 Data were expressed as mean (SD) or median [IQR] or number. *(shivering (2), inadequate for long operation (1), ST-depression (1)) 0.105). Most of the patients had many underlying diseases mainly hypertension and diabetes. The operations were hemiarthroplasty and dynamic hip screw (table 2) and hypotension occurred in half of the patients. There were no statistical differences between the groups in the operative data. Postoperative pain scores were also not different (table 3). Although pethidine consumption in the first 24 hours was less in the FNB group, it did not reach the statistical significance (p = 0.150). Most of the patients in both groups were satisfied with the pain management. No serious complications were found in the first 24 hours. One patient had ST depression in intraoperative period but his ECG normalized without elevated cardiac enzymes. Two patients (1 from control and 1 from FNB group) complained of severe pain and rofecoxib was given. Discussion Fracture of the femur occurs frequently and the surgical correction is one of the common orthopedic procedures. There are various options for the anesthetic management. Regional anesthesia, especially spinal block has been widely used because it was proven to reduce the 1 month mortality rate and deep vein thrombosis. 8 From the national survey from U.K., the anaesthetists used a combined 3-in-1 or femoral nerve 86 «ªï Ë 35 Ë 2 π- ÿπ π 2552

5 Table 3 Postoperative data : pain scores, analgesic requirement, nausea & vomiting and patient s satisfaction Group I (control) Group II (FNB) p-value N = 25 N = 25 Postoperative pain scores 4 hr 3.8 (3.1) 3.2 (3.1) hr 4.3 (2.7) 3.6 (2.5) hr 3.2 (3.5) 3.4 (2.5) hr 3.8 (2.3) 3.6 (2.9) hr 4.0 (2.6) 3.2 (2.2) hr 3.2 (1.7) 3.1 (1.7) 0.80 Pethidine in 24 hours (mg) 50 [0,100] 0 [0,50] 0.15 Rofecoxib (n) 1 1 Nausea and vomiting No Nausea but no vomiting 0 1 Vomiting 1-2 times 0 0 Received ondansetron 0 0 Patient s satisfaction with pain management* 4 [3,4] 4 [3,4] 0.87 Data were expressed as mean (SD) or median [IQR] or number. * (1 = very dissatisfied, 2 = dissatisfied, 3 = fair, 4 = satisfied, 5 = very satisfied) block with general anesthesia but very few used this with regional anesthesia. The regional anesthesia was employed as the sole technique in U.K. and spinal anesthesia was the preferred option. 9 In our tertiary, teaching hospital in developing country, we use spinal block in most of the patients if there are no contraindications. Femoral nerve block has also been used sometimes and its usefulness for postoperative pain management needs to be assessed. In this study, time from trauma to operation was also longer compared with others 2,10 which had the operation within 24 hours. There might be several causes of delayed surgery such as medical consultations and a missed or undiagnosed fractured femur, so many patients came to our hospital very late after trauma. Most patients had fracture neck of femur and had many underlying diseases, mainly hypertension and diabetes. Ischemic heart disease was uncommon due to the general anesthesia preference of the anaesthetists as the hemodynamics were better controlled. The operations were hemiarthroplasty and dynamic hip screw. Half of the patients had hypotension which was not unexpected eventhough the block levels were not too high and the estimated blood loss was about 200 ml. Hypotension was treated with fluid and vasoconstrictor. One patient had ECG changed during hypotension intraoperatively but normalized afterward without elevated cardiac enzymes. The early post-operative Vol. 35, No.2, April-June 2009 Thai Journal of Anesthesiology 87

6 complication was low because many critically ill patients had already been excluded from this study. Pain scores and postoperative analgesic requirement did not differ between the groups. We assessed pain scores every 4 hours and intramuscular pethidine was given according to patient s pain scores ( 4). We did not use PCA for pain management because the PCA machines were not readily available for most patients in our hospital. The pethidine requirement decreased in the FNB group (median 0 mg, range mg) compared with the control group (median 50 mg, range mg) but did not reach statistical significance. From our hypothesis, we expected 50% reduction of pethidine requirement so our sample size was calculated accordingly. Our sample size need to be larger to detect 20-25% reduction of pethidine requirement. Nearly half of the operation performed as an hemiarthroplasty in which anatomical incision was high and femoral nerve block may not be able to cover the pain, which came from the sciatic nerve and lateral femoral cutaneous nerve of thigh. Fournier R, et al studied analgesic effect of femoral nerve block in patients undergoing total hip replacement and found no differences in analgesic requirement as in our study although time to first analgesic request was longer. 11 Haddad FS, et al found that the analgesic requests decreased but both groups (control and FNB), the pain medications were ordered as required and pain scores assessed for only 8 hours. 2 Parker MJ, et al systematically reviewed the benefit of femoral nerve block for fracture femur and found reduction in mean pain score and analgesic requirement but there was heterogeneity of the patients and they included only small number of patients. 12 In a very recent study, Cuvillon P, et al found no benefits of continuous femoral block compared with intravenous propacetamol and subcutaneous morphine. 13 Although the femoral nerve block did not decrease the analgesic requirement, most of our patients rated the pain management as satisfactory. In our protocol, cox2 inhibitor was used as the third analgesic drug, because we concerned about its complication in elderly patients. Only two patients needed it. Study limitations included the fact that the patients were not blinded to group allocation and could have exhibited some placebo effect. There were several types of surgery which undoubtedly could produce different pain patterns but randomization made distribution of surgery types equal in both groups. It was also possible that the nerve block did not work very well in all of the cases but with the aid of peripheral nerve stimulator and because paresthesia was tested after femoral nerve block, this was unlikely. We conclude that a single shot femoral nerve block cannot significantly reduce post-operative analgesic requirements in patients undergoing surgeries for fractured femur. References 1. Lopez S, Gros T, Bernard N, Plasse C, Capdevila X. Fascia iliaca compartment block for femoral bone fractures in prehospital care. Reg Anesth Pain Med ; 28(3) : Haddad FS, Williams RL. Femoral nerve block in extracapsular femoral neck fractures. J Bone Joint Surg Br ; 77(6) : Fletcher AK, Rigby AS, Heyes FL Three-in-one femoral nerve block as analgesia for fractured neck of femur in the emergency department : a randomized, controlled trial. Ann Emerg Med ; 41(2) : Mutty CE, Jensen EJ, Manka MA, Anders MJ, Bone LB. Femoral nerve block for diaphyseal and distal femoral fractures in the emergency department. J Bone Joint Surg 2007 ; 89 : Stewart B, Smith CT, Teebay L, Cunliffe M, Low B. Emergency department use of a continuous femoral nerve block for pain relief for fractured femur in children. Emerg Med J ; 24 : Candal-Couto JJ, McVie JL, Haslam N, Innes AR, Rushmer J. Pre-operative analgesia for patients with femoral neck fractures using a modified fascia iliaca block technique. Injury ; 36(4) : Sia S, Pelusio F, Barbagli R, Rivituso C. Analgesia before performing a spinal block in the sitting position in 88 «ªï Ë 35 Ë 2 π- ÿπ π 2552

7 patients with femoral shaft fracture : a comparison between femoral nerve block and intravenous fentanyl. Anesth Analg ; 99(4) : Parker MJ, Handoll HH, Griffths R. Anaesthesia for hip fracture surgery in adults. Cochrane Database Syst Rev Oct 18;(4):CD Review. 9. Sandby-Thomas M, Sullivan G, Hall JE. A national survey into the peri-operative anaesthetic management of patients presenting for surgical correction of a fractured neck of femur. Anaesthesia 2008 ; 63 : Beaupre LA, Jones CA, Saunders LD, Johnston DW, Buckingham J, Majumdar SR. Best practices for elderly hip fracture patients. A systematic overview of the evidence. J Gen Intern Med ; 20(11) : Review. 11. Fournier R, Van Gessel E, Gaggero G, Boccovi S, Forster A, Gamulin Z. Postoperative analgesia with 3-in-1 femoral nerve block after prosthetic hip surgery. Can J Anaesth ; 45(1) : Parker MJ, Griffiths R, Nerve block (subcostal, lateral cutaneous, femoral, triple, psoas) for hip fracture (Cochrane Review). Cochrane Database Syst Rev ; (2) : CD Review. Update in : Cochrane Database Syst Rev ; (1) : CD Cuvillon P, Ripart J, Debureaux S, Boisson C, Veyrat E, Mahamat A, Bruelle P, Viel E, Eledjam JJ. Analgesia after hip fracture repair in elderly patients: the effect of a continuous femoral nerve block : a prospective and randomised study. Ann Fs Anesth Réanim ; 26(1) : 2-9. (abstract). Vol. 35, No.2, April-June 2009 Thai Journal of Anesthesiology 89

8 Can Femoral Nerve Block Reduce Analgesic Requirement After Surgery for Fractured Femur? Abstract We conducted a prospective randomized controlled trial to evaluate the postoperative analgesic requirement in two groups of patients undergoing surgeries for fractured femur. Group I (control), patients received only spinal block with 0.5% isobaric bupivacaine and group II (FNB) received a single shot femoral nerve block with 0.33% bupivacaine 30 ml combined with spinal block. During Dec 2006-May 2008, 50 patients (25 patients in each group) were included in the trial and analyzed. The surgeries were hemiarthroplasty and dynamic hip screw. The postoperative pain medications were oral paracetamol 1 g every 6 hours and intramuscular pethidine 50 mg every 4 hours if pain scores were 4, and intravenous rofecoxib 40 mg every 12 hours as a third line analgesia drug if the patient still had moderate to severe pain despite receiving paracetamol and pethidine. The pain scores were assessed every 4 hours for the first 24 hours. There were no differences in patientsí demographic, intraoperative data, pain scores and analgesic requirement. A single shot femoral nerve block could not significantly reduce analgesic requirement after surgeries of fractured femur. Keywords : femoral nerve block, fractured femur, analgesia 90 «ªï Ë 35 Ë 2 π- ÿπ π 2552