Revista Brasileira de Anestesiologia

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1 Rev Brs Anestesiol. 2013;63(6): Revist Brsileir de Anestesiologi Officil Publiction of the Brzilin Society of Anesthesiology SCIENTIFIC ARTICLE Femorl nerve block: ssessment of postopertive nlgesi in rthroscopic nterior crucite ligment reconstruction Úrsul Bueno do Prdo Guirro,b,c, *, Elizbeth Mill Tmbr d,e, Fernnd Reinldi Munhoz f Post-Grdution Progrm in Surgery, Universidde Federl do Prná, Curitib, PR, Brzil b Service of Anesthesiology, Hospitl do Trblhdor, Curitib, PR, Brzil c Trte Dor, Curitib, PR, Brzil d Discipline of Anesthesiology, School of Medicine, Pontifíci Universidde Ctólic do Prná, Curitib, PR, Brzil e Service of Anesthesiology, Hospitl Snt Cs de Curitib, Curitib, PR, Brzil f Deprtment of Medicl Residence, Hospitl Snt Cs de Curitib, Curitib, PR, Brzil Received 21 November 2012; ccepted 1 April 2013 KEYWORDS Postopertive nlgesi; Femorl nerve block; Anterior crucite ligment reconstruction; Spinl nesthesi; Trmdol; Adverse event Abstrct Bckground nd objectives: Knee nterior crucite ligment reconstruction (ACLR) my be pinful in the postopertive period. The primry objective of this study ws to evlute whether the use of femorl nerve block (FNB) ssocited with spinl nesthesi would improve the postopertive pin tretment in ACLR nd the secondry objectives were to evlute trmdol request nd dverse events. Method: 53 ptients were rndomly divided into two groups: GA (n =26) received spinl nesthesi nd GB (n = 27) received spinl nesthesi nd FNB. All ptients received multimodl nlgesi nd rescue nlgesics could be requested nytime. Assessments were performed t 6, 12 nd 24 hours. Results: There ws no difference between both groups regrding demogrphic nd cliniclsurgicl vribles. There ws no difference between groups regrding pin intensity. Men pin scores were higher t 12 hours in GA nd there ws no chnge in GB; 55.6% of ptients reported moderte pin in GA nd 53.8% mild pin in GB. There ws no difference regrding trmdol request. There were no serious dverse events: 80.8% of ptients in GB hd motor block of the thigh nd two fell. Conclusions: Anlgesi ws more effective with the combintion of spinl nd FNB, which llowed better control of postopertive pin, ssessed 12 hours fter nesthesi. There ws no difference in trmdol request. Ptients in this study hd no serious dverse events; however, one must be ttentive to motor prlysis nd the possibility of flling when FNB is performed Sociedde Brsileir de Anestesiologi. Published by Elsevier Editor Ltd. All rights reserved. Study conducted t the Post-Grdution Progrm in Surgery, Universidde Federl do Prná, Curitib, PR, Brzil. * Corresponding uthor. E-mil: ursulguirro@gmil.com (U.B.P. Guirro) /$ - see front mtter 2013 Sociedde Brsileir de Anestesiologi. Published by Elsevier Editor Ltd. All rights reserved. doi: /j.bjne

2 484 U. B. P. Guirro et l Introduction The postopertive period of knee nterior crucite ligment reconstruction (ACLR) my be pinful if techniques for pin control re not used properly. 1,2 Potent nlgesics such s opioids my be dministered for postopertive pin tretment in ACLR, however, they my increse the incidence of respirtory depression, excessive sedtion, nuse nd vomiting, leding to incresed length of sty nd hospitl costs. 2,3-6 Femorl nerve block (FNB) hs been successfully used for treting postopertive pin, helps reduce the dministrtion of opioids, but often presents with temporry motor prlysis of the thigh flexor muscles, especilly the qudriceps, which my cuse ptient fll in the postopertive period. 1-4,7,8 Severl techniques for postopertive pin control in ACLR hve been tested nd there is no consensus in current literture bout the most pproprite technique. 9 Techniques such s multimodl nlgesi, 10 intr-rticulr injection of morphine nd locl nesthetic, 9,11 FNB, 1,2,12,13 scitic nerve blockde ssocited with FNB, 14 nd continuous FNB, 15 hve been described, mong others. Among the nlgesic techniques used for postopertive pin control, FNB is n interesting option becuse it is esy to perform, inexpensive, nd my be done in combintion with generl or spinl nesthesi. 16,17 Severl uthors found positive results in pin tretment with the use of FNB for knee opertions, such s rthroscopy, totl knee rthroplsty, nd ACLR. 1,4,6,14,18-21 However, some uthors found no evidence for routine use of FNB 2,13 nd tht it could even be relted to complictions such s infection, hemtom, nd motor prlysis of the thigh flexor muscles The primry objective of this prospective rndomized study ws to evlute postopertive pin in ptients undergoing ACLR with spinl nesthesi, lone or combined with FNB, nd ssess whether ny of the techniques would hve better control of postopertive pin. The secondry objectives were to ssess whether rescue nlgesics request ws needed in the postopertive period, dverse events relted to the techniques, nd medictions used. Ptients nd methods Prospective study strted fter pprovl by the Humn Reserch Ethics Committee of the Helth Deprtment of Prná nd registered under the number 141/2009. All ptients signed the informed. We invited ptients of both sexes, with nterior crucite ligment (ACL) injury, who would undergo ACLR between Mrch 2010 nd Mrch 2011, with rthroscopic ssistnce nd with or without concomitnt opertion of the meniscus nd chondrl crtilge. Inclusion criteri were ge between 18 nd 65 yers, ASA physicl sttus I or II, height 150 to 190 cm, weight 50 to 110 kg, nd body mss index (BMI) between 18.5 nd 40 kg.m 2. Exclusion criteri were ptients with contrindictions to medictions or techniques used, illiterte or cognitive impirment, current or previous history of buse of legl or illegl drugs, pregnnt women, nd emergency surgery or ACL reopertion. Anesthetic techniques Spinl Femorl nerve block Group A 15 mg of isobric bupivcine 0.5% (3 ml) Groups Group B 15 mg of 0.5% isobric bupivcine (3 ml) 100 mg of 0.5% bupivcine without vsoconstrictor (20 ml) Figure 1 Anesthetic techniques used in the study groups. mg, milligrm; ml, milliliter. The study subjects were monitored with pulse oximetry, crdioscopy nd noninvsive blood pressure; venous ccess ws obtined with G ctheter in upper limb nd venous midzolm ws dministered t the mximum dose of 0.1 mg.kg 1 until response to verbl commnd corresponded to score of 3 ccording to Rmsy s clssifiction. Ptients were rndomly ssigned to groups A nd B in mnner previously determined without their knowledge (Fig. 1). Spinl nesthesi ws performed in ll ptients in groups A nd B, in the sitting position fter skin ntisepsis with chlorhexidine, sterile surgicl field plcement, infiltrtion of 2% lidocine with 13 x 4.5 nd 25 x 7 mm needles, in the skin nd into the intervertebrl spce selected (L3-L4, L4-L5 or L5-S1). Disposble Quincke-type cutting needle (27 G) ws used. The subrchnoid spce ws identified by spontneous reflux of CSF, followed by 15 mg of 0.5% isobric bupivcine. Ptients were immeditely plced in the supine position without tilting the operting tble. Anesthesi ws considered stisfctory when there ws loss of cold sensitivity from lower limbs to the umbilicus, tested with n lcohol swb. FNB ws performed only in GB ptients, using the prvsculr puncture technique of the femorl nerve in the lower limb to be operted. After ntisepsis with chlorhexidine nd sterile surgicl field plcement, the needle ws inserted t the midpoint of the line joining the nterior superior ilic spine to the pubic tubercle, lterl to the pulse of the femorl rtery, below the inguinl ligment nd t the inguinl crese level. Approprite neurostimultor needle (Stimuplex A, 22G x 2, 0.7 x 50 mm, B Brun, Melsungen, Germny) ws used, which ws connected to the electricl neurostimultor (Stimuplex, DIG RC, B Brun, Melsungen, Germny), initilly progrmmed with 2 Hz frequency nd 1.0 ma electric current to cuse contrction of the femorl qudriceps muscle centrl portion, evidenced by ptell elevtion. After identifying the correct needle plcement, determined by the persistence of muscle contrction by reducing the stimultion between 0.6 nd 0.2 ma, 0.5% bupivcine (100 mg) ws dministered without vsoconstrictor. All ptients received dipyrone (1 g), ketoprofen (100 mg), cefzolin (1 g), nd ondnsetron (4 mg) through the venous ccess. Oxygen (5 L m 1 ) ws dministered vi fce msk while ptients remined sedted nd they were covered

3 Femorl nerve block: ssessment of postopertive nlgesi in rthroscopic nterior crucite ligment reconstruction No pin Worst pin possible Figure 2 Verbl Numeric Scle. with sheet nd blnket. Hypotension ws defined s 30% decrese from bseline blood pressure, nd corrected with bolus dose of ephedrine (5 mg) s needed. ACLR were performed by the sme tem tht hrvested the grft from the sme knee with ACL injury, which could be the centrl third of the ptellr tendon or tendons of the flexor semitendinosus nd grcilis, ccording to tendons condition of ech ptient. The surgicl technique ws similr, regrdless of the grft chosen. At dischrge to the wrd, ll ptients received crd with the Verbl Numericl Scle (VNE) (Fig. 2). All ptients were told tht if the pin score ws equl to or greter thn 4, they could request the nlgesic trmdol or the pinkiller t ny time. Postopertive prescription ws stndrdized for ll ptients in both groups with generl diet nd wter d libitum, intrvenous cefzolin (1 g/every 8 hours), diluted dipyrone (1 g/every 6 hours), ketoprofen (100 mg/every 12 hours t 30 minutes), trmdol (100 mg) or pinkiller diluted in 100 ml 0.9% sline t 30 minutes, only if requested by the ptient, nd metocloprmide (10 mg) in cse of nuse or vomiting. Pin intensity ssessments were mde ccording to VNS in which 0 mens no pin nd 10 the worst pin possible, t three times: Time 1 (T1): 6 hours fter spinl nesthesi. At this time, the ptient should be ble to extend the thigh nd flex the knee of the non-operted limb nd define the end of the spinl nesthesi effects. After mking sure the ptient understood the pin scle, the VNS score choice ws requested without interference from the evlutor. Ptient ws reminded tht he could request trmdol or pinkiller if the VNS score ws equl to or greter thn 4. The success of FNB ws evluted in GB ptients with therml sensitivity test (guze soked with 70% lcohol solution) nd technique ws considered successful if there ws bsence of therml sensitivity in the nterior region of the operted thigh nd presence of senstion in contrlterl thigh. Time 2 (T2): 12 hours fter spinl nesthesi. Ptients chose the VNS score nd were reminded tht they could request trmdol or pinkiller if pin score ws equl to or greter thn 4. Time 3 (T3): 24 hours fter spinl nesthesi. Ptients chose the VNS score, nd complints, dverse events or complictions were recorded, s well s whether or not trmdol ws requested nd, if requested, how mny hours fter spinl nlgesi it ws requested. Dt were collected prospectively, using dt collection instrument, nd entered into spredsheet, checked nd exported to the Sttistic softwre. For comprison of A nd B groups regrding quntittive vribles, Mnn-Whitney test nd Student s t-test were used for independent smples, nd chi-squre nd Fisher s exct tests for qulittive vribles. For pin score evlution between groups, nonprmetric Mnn-Whitney nd Friedmn tests were used, nd Friedmn post hoc used for multiple comprisons. A p-vlue of less thn 0.05 (or 5%) ws considered sttisticlly significnt. According to previous sttisticl study, the smple size of 30 ptients in ech group would be required to identify significnt difference of two cores in VNS between A nd B groups, with probbility of type-i error equl to 0.05 nd 84% power. Results In totl, 53 ptients were evluted nd rndomly divided into Group A (GA = control) nd Group B (GB = intervention). In GA, initilly with 30 ptients, there were three exclusions: two due to intropertive chnge (rthroscopy without ACLR) in surgicl pln nd one due to hospitl dischrge before the first 24 hours postopertively, with lost to follow-up; therefore, 27 ptients were evluted. In GB, initilly with 30 ptients, there were two refusls to prticipte nd two exclusions due to hospitl dischrge before the first 24 hours postopertively, with lost to follow-up; therefore, 27 ptients were evluted. There ws no filure of ny FNB. Groups were homogeneous in terms of gender, ge, weight, height, nd BMI (Tble 1) nd there ws no difference regrding ASA sttus, operted side, grft used in ACLR, nd concomitnt opertion on meniscus or chondrl crtilge (Tble 2). Regrding postopertive pin intensity, ptients in groups A nd B were compred between the evluted times (T1, T2, nd T3), nd this comprison between ech time showed no sttisticlly significnt difference between groups (Tble 3). The men pin scores found in T1 nd T3 ws below 3 in both groups, but the scores t T2 exceeded tht vlue. In order to evlute whether the incresed scores were significnt, times were compred within ech group. In GA (Tble 4), the highest men pin scores t T2 (3.9 ± 2.5) ws different nd sttisticlly significnt compred to T1 nd T3, p = (Tble 5). In GB, the incresed pin scores t T2 (3.2 ± 2.5) showed no difference compred to T1 nd T3. GA ptients hd mximum pin 12 hours fter spinl nesthesi nd GB ptients hd no mximum pin (Tble 6). Postopertive medin scores re shown in Fig. 3. In order to ssess T2, during which ptients ssigned higher scores of pin, we strtified pin scores s bsent

4 486 U. B. P. Guirro et l Tble 1 Demogrphic chrcteristics. Dt Group A (n = 27) Group B (n = 26) p Gender Mle 22 (81.5%) 20 (76.9%) Femle 5 (18.5%) 6 (23.1%) Age (yers) min-mx b Men ± SD 31.3 ± ± 9.8 Weight (kg) min-mx b Men ± SD 79.7 ± ± 13.5 Height (m) min-mx b Men ± SD ± ± 0.83 BMI (kg m 2 ) min-mx b Men ± SD 27.3 ± ± 3.7 BMI, body mss index; kg, kilogrm; kg m 2, kilogrm per squre meter; m, meter; mx, mximum; min, minimum; SD, stndrd devition. Chi-squre test. b Student s t-test. Tble 2 Clinicl nd surgicl chrcteristics. Dt Group A (n = 27) Group B (n = 26) p Frequency % Frequency % Physicl sttus ASA I ASA II Side Right Left Grft Flexor Ptellr Concomitnt surgery Yes No ASA I nd II, physicl sttus 1 nd 2, respectively, defined by the of the Americn Society of Anesthesiologists clssifiction. Chi-squre test. (score = 0), mild (score = 1-3), moderte (score = 4-7), nd severe (score = 8-10). There ws difference between groups: GA ptients reported moderte pin (55.6%) nd GB mild pin (53.8%), p = However, lso t T2, both GA nd GB ptients reported severe pin, 3.7% nd 11.5%, respectively (Tble 7). Of GA ptients, 51.9% sked for the rescue nlgesic, trmdol, in the postopertive period evluted nd only 38.5% of GB ptients mde the sme request, but this dt ws not sttisticlly significnt, p = (Tble 8). No ptient in both GA nd GB requested more thn one dose of the rescue nlgesic (100 mg trmdol) in the study period. Among ptients who requested the rescue nlgesic, the men time for the request ws 10.9 ± 2.7 hours in GA nd 12.9 ± 4.4 hours in GB, but this difference ws not sttisticlly significnt, p = 0.1 (Tble 9). None of the ptients hd serious surgicl or nesthetic complictions in this study. In GA, two ptients (7.4%) hd nuse nd vomiting, one (3.7%) ws treted for post-durl puncture hedche, nd one (3.7%) reported senstion of cold feet. Of the ptients undergoing FNB in GB, 21 (80.8%)

5 Femorl nerve block: ssessment of postopertive nlgesi in rthroscopic nterior crucite ligment reconstruction 487 Tble 3 Pin intensity t rest. Dt Group A (n = 27) Group B (n = 26) p T1 min-mx Men ± SD 2.1 ± ± 3.0 Medin 2 3 T2 min-mx Men ± SD 3.9 ± ± Medin T3 min-mx Men ± SD 2.4 ± ± Medin 2 2 Mx, mximum; min, minimum; SD, stndrd devition; T1, 6 hours fter spinl nesthesi; T2, 12 hours fter spinl nesthesi; T3, 24 hours fter spinl nesthesi. Non-prmetric Mnn-Whitney test. Tble 4 Evolution of pin t rest in group A. Dt Group A (n = 27) p T1 min-mx 0-6 Men ± SD 2.1 ± 2 Medin 2 T2 min-mx 0-10 Men ± SD 3.9 ± Medin 4 T3 min-mx 0-6 Men ± SD 2.4 ± 2 Medin 2 Mx, mximum; min, minimum; SD, stndrd devition; T1, 6 hours fter spinl nesthesi; T2, 12 hours fter spinl nesthesi; T3, 24 hours fter spinl nesthesi. Friedmn s nonprmetric test. Tble 6 Evolution of pin t rest in group B. Dt Group B (n = 26) p T1 min-mx 0-10 Men ± SD 2.5 ± 3 Medin 2 T2 min-mx 0-9 Men ± SD 3.2 ± Medin 2.5 T3 min-mx 0-6 Men ± SD 2.3 ± 1.6 Medin 2 Mx, mximum; min, minimum; SD, stndrd devition; T1, 6 hours fter spinl nesthesi; T2, 12 hours fter spinl nesthesi; T3, 24 hours fter spinl nesthesi. Friedmn s nonprmetric test. Tble 5 Time comprison regrding pin evolution in group A. Dt T1 vs. T2 < T1 vs. T T2 vs. T3 < T1, 6 hours fter spinl nesthesi; T2, 12 hours fter spinl nesthesi; T3, 24 hours fter spinl nesthesi. Friedmn s post-hoc multiple comprisons test. hd trnsient motor prlysis of thigh muscles nd, of those, two (7.7%) fell while trying to wlk during the study period. Still in GB, one ptient (3.7%) reported pin t the FNB puncture site (Tble 10). p Discussion Although new techniques hve been developed for postopertive pin tretment, none of them proved to be completely effective; thus, reserchers re still trying to improve them. In Western countries, bout 40% of outptients nd up to 70% of hospitlized ptients suffer from pin of moderte to severe intensity fter n opertion, with orthopedic surgeries identified s hving the highest rte of pin complints. 17 Improvement in tretment of cute pin is crucil to the well-being of ptients nd to reduce the chronicity of pin Of ptients undergoing routine surgicl procedures, between 10% nd 50% my suffer from chronic postopertive pin, especilly femle ptients who presented with pin before surgery. Opioids hve been used for tretment nd prevention of postopertive pin; however, peripherl nerve blocks hve prominent plce

6 Pin ssessment score 488 U. B. P. Guirro et l Medin; 25-75%; min-mx Group A Group B T1 T2 T3 Figure 3 Intensity of pin t rest. Mx, mximum; min, minimum; T1, 6 hours fter spinl nesthesi; T2, 12 hours fter spinl nesthesi; T3, 24 hours fter spinl nesthesi. Ptients in this study hd no difference in demogrphic, clinicl nd surgicl profile, nd these dt re similr to those reported by other uthors. 1,13,16,19,21 The choice of the flexor muscle tendon grfting ws motivted by the tendons condition of ech ptient, but sometimes the choice ws mde ccording to the vilbility of mteril in the hospitl nd, therefore, did not llow further study of this vrible. The meniscus surgery nd simultneous repir of chondrl lesions occurred in most ptients in this smple, which lso hppened in nother study, s these lesions re often ssocited with ACL injury. 13 The study groups hd similr men scores on ssessments t 6, 12 nd 24 hours fter surgery, but GB, submitted to FNB, showed no increse in men scores t 12 hours fter nesthesi, which ws reported by GA ptients who were not submitted to FNB. In the sme time intervl of 12 hours (T2) fter nesthesi, bout hlf of the GB ptients hd mild pin, unlike GA tht did not undergo such blockge, in which hlf of the ptients reported moderte pin. These dt llow us to sy tht when FNB ws ssocited with spinl nesthesi there ws better pin control within 12 hours fter nesthesi for ACLR. However, still t T2, 3.7% of ptients in GA nd 11.5% of ptients in GB reported severe pin, which shows tht, regrdless of the technique used in this study, dequte pin control hs filed in some ptients. Tble 7 Pin Strtified t T2 (12 hours fter spinl nesthesi). Dt Group A (n = 27) Group B (n = 26) p Frequency % Frequency % No pin Mild Moderte Severe Chi-squre test. Tble 8 Trmdol request. Dt Group A (n = 27) Group B (n = 26) p Frequency % Frequency % Yes No Fisher s exct test. Tble 9 Time between spinl nesthesi nd trmdol request. Dt Group A (n = 27) Group B (n = 26) p b min-mx Men ± SD 10.9 ± ± 4.4 Medin Mx, mximum; min, minimum; SD, stndrd devition. Time (hours). b Student s t-test.

7 Femorl nerve block: ssessment of postopertive nlgesi in rthroscopic nterior crucite ligment reconstruction 489 Tble 10 Adverse events. Dt Group A (n = 27) Group B (n = 26) Frequency % Frequency % Motor block of qudriceps muscle Ptient fll PONV Hedche fter spinl nesthesi FNB locl pin Spinl nesthesi filure Cold senstion in lower limb FNB, femorl nerve block; PONV, postopertive nuse nd vomiting. Similr result ws found by Souz et l. 1 who evluted ptients undergoing knee surgery with spinl nesthesi, lone or combined with FNB, nd those who received FNB hd less pin in the ssessment between 6 nd 10 hours nd, in the evlution between 10 nd 24 hours, no difference ws found between scores, with predominnce of no pin nd mild pin nswers. Ptients evluted by Chn et l. 21 lso showed better control of postopertive pin when FNB ws dministered with 0.5% bupivcine. Pin scores were significntly lower in ptients who received FNB before or fter ACLR, compred to controls receiving FNB with sline solution. Other uthors hve found different results from those of this study nd did not identify evidence for FNB regulr indiction.[2,13,26] A met-nlysis tht included 13 studies ssessed the qulity of nlgesi provided by FNB in ACLR nd, lthough the uthors conclude tht there is no benefit in the regulr indiction of this blockde, the results showed better pin control with FNB combined with multimodl nlgesi. The uthors suggested tht the studies included in the met-nlysis re heterogeneous, which hindered the comprison. 2 The control of postopertive pin in this study could hve been more effective with the combintion of other blocks to FNB. Scitic 14 nd obturtor 27 nerve blocks could hve ided in controlling pin nd decrese pin scores nd, possibly, rescue nlgesic request. In this study, the rescue mediction of choice for treting pin ws trmdol becuse it is wek opioid used in hospitl routine. However, literture reports the use of morphine, oxycodone, nd nti-inflmmtory, mong others, for ACLR. 1,6,13,16,21,26 The criteri for trmdol request in this study ws the ptient s perception tht pin intensity would be moderte to severe, i.e., VNS score equl to or greter thn 4. 28,29 Despite the subjectivity of pin ssessment, which depends on current nd pst individul experience of ech ptient, s well s level of nxiety, understnding, nd cognition, some uthors reported tht there re similr scores between different pin scles. 30 Some ptients reported pin equl to or greter thn 4 nd chose not to request trmdol, despite cler guidnce tht they could do it. The most common llegtions were: Being in pin fter surgery is norml nd I ws frid to get ddicted. Such ssertions re frequent mong ptients who re not regulr users of nlgesics nd my hve ffected the results of this study. 31 Trmdol request ws not different between groups A nd B on the first postopertive dy, which is in greement with other uthors. 13,26 However, the rescue nlgesic request ws different with the use of FNB in studies using generl nesthesi or including other surgeries, such s knee rthroplsty. 16,21 Most dverse events presented by ptients in this study were not serious. Trnsient motor prlysis of qudriceps muscle occurred in most ptients who received FNB. Such motor prlysis is often described in literture nd my be relted to the locl nesthetic chosen, its concentrtion, nd method of dministrtion. 1,15,16,26 In this study, two ptients who underwent FNB fell postopertively, both presented motor prlysis nd the fll ws not ssocited with other cuses, such s crdic or neurologicl. None of these ptients hd surgery problems or new injury nd ll hd stisfctory outcome. After the fll of the first ptient, the study protocol ws mended nd ll ptients in both groups were dvised not to wlk without n escort nd lwys with the support of crutches, in ddition to remin lert to the possibility of such ccident. This wrning my hve prevented new flls nd influenced the results. No ptient in this study hd severe compliction, such s trnsient or permnent neuroplegi. Other uthors hve ssocited motor prlysis of the thigh flexor muscles with single shot FNB, which seemed to be more intense with bupivcine thn with ropivcine. 1,7,16,26,32 Studies evluting repeted injections or continuous infusion of locl nesthetic found no difference regrding motor prlysis. 15 Fll of ptients hs been reported in the literture, nd some ptients required new surgicl pproch. 7,8 FNB hs low compliction rte when performed with proper technique. Reports of serious dverse events relted to FNB re rre. However, vsculr puncture nd hemtom, locl inflmmtion, infection, trnsient nd permnent neuroplegi hve been reported. 8,15,22 There were two cses of nuse nd vomiting in this study fter trmdol dministrtion. Ptients were treted

8 490 U. B. P. Guirro et l with metocloprmide nd there ws no dely in the scheduled hospitl dischrge. Nuse nd vomiting my be relted to the dministrtion of opioids, which, prt from cusing discomfort to ptients, increse costs nd my dely hospitl dischrge. 5 When the nlgesic technique reduced the request for rescue opioid, the episodes of nuse reduced. 6 This study hs limittions. Time of hospitl dischrge ws not ssessed becuse four ptients hd socil condition tht prevented complete observtion of tht time intervl, which would led to dely in intercity trnsporttion. It would hve been interesting to evlute these ptients pin for longer period of time, perhps until full recovery; however, for the reson lredy mentioned, this evlution ws not vible. Spinl nesthesi nd FNB motor block my hve interfered with the ssessment t T1 nd lso resulted in complints of some ptients. Both techniques ssessed (spinl nd FNB) could be widely used in nesthesiologists dily prctice. Spinl nesthesi is mnged by ll nesthesiologists, while FNB is not; however, FNB is esy to perform nd quite sfe, s long s ntomy nd principles of ntisepsis re considered. After dt nlysis, it cn be concluded tht postopertive nlgesi evluted with the use of VNS in ptients undergoing ACLR ws more effective with the combintion of spinl nd FNB nd llowed better control of postopertive pin 12 hours fter nesthesi compred to spinl nesthesi lone. Regrding trmdol request, there ws no difference between groups. Adverse events presented by ptients in this study were not serious, but one must be wre of qudriceps muscle prlysis nd the possibility of flling fter FNB. However, despite the techniques used, there re still complins of severe pin in ptients undergoing ACLR, suggesting tht further studies re needed for dequte control of postopertive pin. Conflicts of interest The uthors declre no conflicts of interest. Acknowledgments We thnk ll collegues, nesthesiologists nd orthopedic surgeons, of the Hospitl do Trblhdor who ssisted in conducting this study, Prof. Ary Elis Sbbg Junior for his help with the sttisticl nlyzes, nd the medicl students Frncielly Lucvei nd Jnín Cmpos who ssisted with the references. References 1. Souz, RL, Corre CH, Henriques MD, et l. Single-injection femorl nerve block with 0.25% ropivcine ou 0.25% bupivcine for postopertive nlgesi fter totl knee replcement or nterior crucite ligment repir. J Clin Anesth. 2008;20: Mll NA, Wright RW. Femorl nerve block use in nterior crucite ligment reconstruction surgery. Arthroscopy. 2010;26: Frost S, Grossfeld S, Kirkley B, et l. The efficcy of femorl nerve block in pin reduction for outptient hmstring nterior crucite ligment reconstruction: double-blind, prospective, rndomized tril. Arthroscopy. 2000;16: Fonsec NM, Ruzi RA, Ferreir FX, et l. 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