Evaluation of "3 in 1" lumbar plexus block in patients having muscle biopsy

Evaluation of femoral nerve blockade following inguinal paravascular block of Winnie: are there still lessons to be learnt?

Lower limb peripheral nerve blocks are used to provide surgical anaesthesia or postoperative analgesia. Anatomical texts imply that femoral and saphenous nerve blocks be evaluated by sensory testing of the skin overlying the anterior aspect of the thigh, and the medial aspect of the foot, respectively. We have mapped the distribution of anaesthesia in 25 adults following femoral nerve blockade, performed using the inguinal paravascular technique of Winnie. There was substantial interindividual variation in the area of anaesthesia. Only the skin overlying the middle third of the medial thigh was consistently blocked in 100% of patients. The distribution of anaesthesia conformed to anatomical text descriptions in 24% of cases. We conclude that demonstration of complete quadriceps paralysis confirms femoral nerve blockade. Failing that, sensory evaluation of a femoral nerve block should involve testing the skin of the middle third of the medial aspect of the thigh. The skin overlying the anteromedial aspect of the middle third of the leg should be evaluated for saphenous nerve block.

La neurostimulation n’augmente pas le taux de succès du bloc du nerf saphène

PURPOSE

To evaluate neurostimulation of motor components of the vastus medialis muscle and the rectus femoris muscle, with a view to blocking the medial sensory fibres of the saphenous nerve.

METHOD

First we dissected four femoral trigones, in order to select our puncture point. We were able to observe that, at the flexion crease of the thigh, the different fibers that make up the femoral nerve were clustered together and the saphenous nerve and the vastus medialis nerve had not yet separated from the femoral stem. Secondly, we conducted a prospective clinical study among 71 patients who had undergone surgery on the lower third of the leg with a sciatic block and a saphenous nerve block. The saphenous nerve block was performed using 10 mL of local anesthetic, by puncturing the flexion crease of the thigh in a bid to obtain one of two muscle responses: medial (contraction of the vastus medialis muscle) or anterior (contraction of the rectus femoris muscle and elevation of the patella).

RESULTS

There was an overall success rate of 80% with the saphenous nerve block, with no statistical difference existing between the two response types. Average duration for the block to be completed was two minutes and it took an average of 15 min before the anesthesia took effect. No complications were encountered, apart from a puncture of the femoral artery, which was clinically inconsequential.

CONCLUSION

Neurostimulation of the vastus medialis muscle has the same effect as neurostimulation of the rectus femoris muscle with respect to anesthesia of the saphenous nerve. Neurostimulation of the medial compartment of the femoral nerve saves local anesthetic, compared to a standard femoral block.

Fascia Iliaca Block for an Infant with Arthrogryposis Multiplex Congenita Undergoing Muscle Biopsy

Children with arthrogryposis multiplex congenita often require multiple surgical procedures. We present a case of a neonate with arthrogryposis multiplex congenita in which intubation was judged to be technically difficult and in which peripheral regional anesthesia allowed us to obtain a satisfactory muscle biopsy without risking the complications of general anesthesia.

Onset time, quality of blockade, and duration of three-in-one blocks with levobupivacaine and bupivacaine

Levobupivacaine is the isolated S(-)-stereoisomer of racemic bupivacaine. Important pharmacodynamic properties of levobupivacaine have not been determined for the femoral three-in-one block. In this randomized, controlled, double-blinded trial, we studied 60 ASA physical status I-III patients scheduled for surgery of the lower limb. A nerve-stimulator-guided three-in-one block was performed as supplemental analgesic therapy with 20 mL of bupivacaine 0.5% (n = 20), levobupivacaine 0.5% (n = 20), or levobupivacaine 0.25% (n = 20). Sensory onset time, quality of blockade, and duration of blockade were assessed by pinprick test in the central sensory innervation region of the femoral nerve (distribution of the anterior femoral cutaneous nerve). A rating scale from 100% (normal sensation) to 0% (no sensation at all) as compared with the contralateral leg was used. No significant difference in sensory onset time among the three local anesthetic solutions was observed (mean [95% confidence interval]): bupivacaine 0.5%, 27 min (20-33 min); levobupivacaine 0.5%, 24 min (18-30 min); and levobupivacaine 0.25%, 30 min (23-36 min) (P = 0.49). The analgesic quality of the blockade was also not significantly different among the three groups, whereas a complete sensory block was achieved in significantly fewer patients in the levobupivacaine 0.25% group (P = 0.02). The duration of blockade was significantly shorter with levobupivacaine 0.25% compared with the other groups: bupivacaine 0.5%, 1053 min (802-1304 min); levobupivacaine 0.5%, 1001 min (844-1158 min); and levobupivacaine 0.25%, 707 min (551-863 min) (P = 0.01). Levobupivacaine 0.5% is recommended instead of bupivacaine 0.5% for the three-in-one block.

A clinical comparison of psoas compartment and inguinal paravascular blocks combined with sciatic nerve block

The extent of inguinal paravascular blockade and psoas compartment blockade with sciatic nerve block was evaluated in 60 patients. Volumes of 30 ml and 20 ml 0.35% bupivacaine with 1/200,000 epinephrine were injected for lumbar plexus and sciatic nerve block, respectively. Complete lumbar plexus blockade was achieved in 73% of the group who were treated with the psoas compartment technique and 43% of the group who were treated with the inguinal paravascular technique. Sensory blockade of the femoral, lateral femoral cutaneous and obturator nerves was obtained in 100%, 97% and 77% of the patients in the psoas compartment group, and 93%, 63% and 47% of the patients in the inguinal paravascular group, respectively. Sensory blockade of the lateral femoral cutaneous and obturator nerves was more rapid with psoas compartment block. The study suggests that the psoas compartment block is effective in blocking the femoral, lateral femoral cutaneous and obturator nerves, but the inguinal paravascular block is only effective in blocking the femoral nerve.

An evaluation of the cutaneous distribution after obturator nerve block

In 1973, Winnie et al. introduced the inguinal paravascular three-in-one block, which allegedly provides anesthesia of three nerves--the femoral, lateral cutaneous femoral, and obturator nerves--with a single injection. This concept was undisputed until the success of the obturator nerve block was reassessed by using evidence of adductor weakness rather than cutaneous sensory blockade, the latter being variable in its distribution and often absent. We performed this study, therefore, to evaluate the area of sensory loss produced by direct injection of local anesthetic around the obturator nerve. A selective obturator nerve block with 7 mL of 0.75% ropivacaine was performed in 30 patients scheduled for knee surgery. Sensory deficit and adductor strength were evaluated for 30 min by using sensory tests (cold and light-touch perception) and the pressure generated by the patient's squeezing a blood pressure cuff placed between the knees. Subsequently, a three-in-one block was performed, and the sensory deficit was reassessed. The obturator nerve block was successful in 100% of cases. The strength of adductors decreased by 77% +/- 17% (mean +/- SD). In 17 patients (57%), there was no cutaneous contribution of the obturator nerve. The remaining 7 patients (23%) had an area of hypoesthesia (cold sensation was blunt but still present) on the superior part of the popliteal fossa, and the other 6 (20%) had sensory deficit located at the medial aspect of the thigh. The three-in-one block resulted in blockade of the lateral aspect of the thigh in 87% of cases, whereas the anteromedial aspect was always anesthetized. By use of magnetic resonance imaging in eight volunteers, we demonstrated that the obturator nerve has already divided into its two branches at the site of local anesthetic injection. However, the injection of blue dye after having simulated the technique in five cadavers showed that the fluid regularly spread to both branches. We conclude that after three-in-one block, a femoral nerve block may have been assessed as an obturator nerve block in 100% of cases when testing the cutaneous distribution of the obturator nerve on the medial aspect of the thigh.

IMPLICATIONS

Previous studies reporting an incidence of obturator nerve block after three-in-one block may have mistaken a femoral nerve block for an obturator nerve block in 100% of cases when the cutaneous distribution of the obturator nerve was assessed on the medial aspect of the thigh. The only way to effectively evaluate obturator nerve function is to assess adductor strength.

Magnetic resonance imaging of the distribution of local anesthetic during the three-in-one block

The three-in-one technique of simultaneously blocking the femoral, the lateral femoral cutaneous (LFC), and the obturator nerves by a single injection of a local anesthetic was first described in 1973, and it was suggested that the underlying mechanism was one of cephalad spread resulting in a blockade of the lumbar plexus. Today, the technique is widely used in surgery and pain management of the lower limb. Many investigators have, however, reported suboptimal analgesia levels, particularly in the obturator nerve. The purpose of this prospective study was to trace the distribution of a local anesthetic during a three-in-one block by means of magnetic resonance imaging (MRI). Seven patients scheduled for surgery of the lower limb were analyzed with the aid of a primary MRI and then received three-in-one blocks using 30 mL of bupivacaine 0.5% under the guidance of a nerve stimulator. A secondary MRI was performed to determine the distribution pattern of the local anesthetic. It emerged that the local anesthetic blocks the femoral nerve directly, the LFC nerve through lateral spread, and the anterior branch of the obturator nerve by slightly spreading in a medial direction. No involvement of the proximal and posterior portions of the obturator nerve was observed, nor was there any cephalad spread that could have resulted in a lumbar plexus blockade. We therefore conclude that the basis of the three-in-one block is confined to lateral, medial, and caudal spread of the local anesthetic, which effectively blocks the femoral and LFC nerves, as well as the distal anterior branch of the obturator nerve.

IMPLICATIONS

We demonstrate by using magnetic resonance imaging that the mechanism of a three-in-one block is one of lateral, caudal, and slight medial spread of a local anesthetic with subsequent blockade of the femoral, the lateral femoral cutaneous, and the anterior branch of the obturator nerves. It does not involve cephalad spread of the local anesthetic with blockade of the lumbar plexus.

[Continuous analgesia with a femoral catheter: plexus or femoral block?]

OBJECTIVE

To evaluate the spread and quality of sensitive blockade produced by continuous and prolonged use of a femoral catheter inserted for postoperative analgesia.

STUDY DESIGN

Prospective non comparative evaluation.

PATIENTS

The study included 20 consecutive patients undergoing major knee surgery with postoperative analgesia obtained with a femoral catheter, a technique commonly used in our department.

METHODS

Regional analgesia was induced after surgery with a bolus injection of 30 mL of 2% lidocaine with 1:200,000 epinephrine 1 in 200,000, maintained by continuous infusion of 1% lidocaine + morphine 0.03 mg.mL-1 + clonidine 2 micrograms.mL-1 for 48 h. The infusion rate was 0.1 mL.kg-1.h-1. The evaluation was based on: 1) the quality of analgesia at rest, at 30 min, h1, h3, h6, h12, h24 and h48; 2) the sensitive and motor blockade at the same time intervals.

RESULTS

A "3 in 1" block was only observed in 50% of patients after the initial bolus via the femoral catheter. During the maintenance of analgesia with a continuous infusion a blockade of the three main nerves of the lumbar plexus occurred in less than 20% of patients after 6 h and was limited to the territory of the femoral nerve in 45 to 50% of patients after 12 to 48 h. In all cases the median values of VAS were below 42 mm.

CONCLUSION

In most patients, a local anaesthetic administered continuously via a femoral catheter produces a blockade limited to the femoral nerve. These data do not substantiate the conclusions by those who consider they are producing a continuous "3 in 1" block with this technique. However, it is obviously not essential to produce a sensitive blockade of the three main nerves of the lumbar plexus to obtain an effective analgesia after knee surgery.

Comparison of the three-in-one and fascia iliaca compartment blocks in adults: clinical and radiographic analysis

The 3-in-1 (Group 1) and fascia iliaca compartment (Group 2) blocks, two single-injection, anterior approach procedures used to simultaneously block the femoral, obturator, and lateral femoral cutaneous (LFC) nerves, were compared in 100 adults after lower limb surgery. Pain control, sensory and motor blockades, and radiographically visualized spread of local anesthetic solution were studied prospectively. Both approaches provided efficient pain control using 30 mL of 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine and 5 mL of contrast media (iopamidol). Complete lumbar plexus blockade was achieved in 18 (38%) Group 1 and 17 (34%) Group 2 patients (n = 50 patients per group). Sensory block of the femoral, obturator, genitofemoral, and LFC nerves was obtained in 90% and 88%, 52% and 38%, 38% and 34%, and 62% and 90% of the patients in Groups 1 and 2, respectively (P < 0.05). Sensory LFC blockade was obtained more rapidly for the patients in Group 2 (P < 0.05). Concurrent internal and external spread of the local anesthetic solution under the fascia iliaca and between the iliacus and psoas muscles was noted in 62 of the 92 block procedures analyzed radiographically. Isolated external spreads under the fascia iliaca and over the iliacus muscle were noted in 10% and 36% of the patients in Groups 1 and 2, respectively (P < 0.05). The local anesthetic solution reached the lumbar plexus in only five radiographs. We conclude that the fascia iliaca compartment block is more effective than the 3-in-1 block in producing simultaneous blockade of the LFC and femoral nerves in adults. After both procedures, blockade was obtained primarily by the spread of local anesthetic under the fascia iliaca and only rarely by contact with the lumbar plexus.

IMPLICATIONS

In adults, the two anterior approaches, 3-in-1 and fascia iliaca compartment blocks, provide effective postoperative analgesia. The fascia iliaca compartment technique provides faster and more consistent simultaneous blockade of the lateral femoral cutaneous and femoral nerves. Sensory block is caused by the spread of local anesthetic solution under the fascia iliaca and only rarely to the lumbar plexus.

Ultrasonographic guidance improves sensory block and onset time of three-in-one blocks

The use of ultrasound reduces the onset time, improves the quality of sensory block, and minimizes the risks associated with the supraclavicular approach for brachial plexus and stellate ganglion blockade. The present study was designed to evaluate whether ultrasound also facilitates the approach for 3-in-1 blocks. Forty patients (ASA physical status II or III) undergoing hip surgery after trauma were randomly assigned to two groups. In the ultrasound (US) group, 20 mL bupivacaine 0.5% was administered under US guidance, whereas in the control group, the same amount and concentration of local anesthetic was administered with the assistance of a nerve stimulator (NS). After US- or NS-based identification of the femoral nerve, the local anesthetic solution was administered, and the distribution of the local anesthetic solution was visualized and recorded on videotape in the US group. The quality and the onset of the sensory block was assessed by using the pinprick test in the central sensory region of each of the three nerves and compared with the same stimulation on the contralateral leg every 10 min for 60 min. The rating was performed using a scale from 100% (uncompromised sensibility) to 0% (no sensory sensation). Heart rate, noninvasive blood pressure, and oxygen saturation were measured at short intervals for 60 min. The onset of sensory blockade was significantly shorter in Group US compared with Group NS (US 16 +/- 14 min, NS 27 +/- 16 min, P < 0.05). The quality of the sensory block after injection of the local anesthetic was also significantly better in Group US compared with Group NS (US 15% +/- 10% of initial value, NS 27% +/- 14% of initial value, P < 0.05). A good analgesic effect was achieved in 95% of the patients in the US group and in 85% of the patients in the NS group. In the US group, visualization of the cannula tip, the femoral nerve, the major vessels, and the local anesthetic spread was possible in 85% of patients. Incidental arterial puncture (n = 3) was observed only in the NS group. We conclude that an US-guided approach for 3-in-1 block reduces the onset time, improves the quality of the sensory block and minimizes the risks associated with this regional anesthetic technique.

IMPLICATIONS

The onset time and the quality of a regional anesthetic technique for the lower extremity is improved by ultrasonographic nerve identification compared with older techniques.

Electromyographic comparison of obturator nerve block to three-in-one block

Obturator nerve block during spinal, epidural, or general anesthesia without muscle relaxants has been recommended for transurethral surgery to prevent thigh adductor muscle contractions during operative electrocautery. We investigated the effectiveness of direct obturator and 3-in-1 nerve motor blocks in 44 patients undergoing transurethral surgery during spinal anesthesia with isobaric bupivacaine. Patients were randomly assigned to receive 3-in-1 block with 40 mL (n = 13) or 50 mL (n = 11) of 1.5% lidocaine plus epinephrine, or direct obturator nerve block with 10 mL of 2% lidocaine plus epinephrine (n = 20). After both direct obturator and 3-in-1 blocks, compound muscle action potential (CMAP) testing of the obturator nerve was performed at 1-10-s intervals for 10 min. In patients given direct obturator nerve block (n = 20), CMAP amplitude decreased by 88.8 +/- 21% (mean +/- SD) from baseline. In contrast, 3-in-1 block reduced the evoked CMAP amplitude by 7.4 +/- 19% (P < 0.05). Peak lidocaine plasma levels of 1.6 +/- 0.2 micrograms/mL (range 1.0-2.8 micrograms/mL) were reached 60-90 min after the block in those patients receiving 50 mL of local anesthetic. The 3-in-1 technique fails to predictably result in effective motor block of the obturator nerve and thus may not prevent inadvertent thigh adductor muscle contractions during transurethral surgery. A direct approach to the obturator nerve is significantly more effective in producing motor block, and even when given in larger than recommended dosages it results in subtoxic peak plasma lidocaine concentrations.

Femoral nerve "sheath" for inguinal paravascular lumbar plexus block is not found in human cadavers

STUDY OBJECTIVE

To determine if a femoral nerve sheath capable of conveying local anesthetic to the lumbar plexus and the obturator nerve exists in human cadavers.

DESIGN

Injection of methylene blue dye into the femoral nerves of human cadavers followed by dissection and observation of dye distribution.

SETTING

University medical center pathology department autopsy room.

PATIENTS

Six fresh adult cadavers about to undergo postmortem examination.

INTERVENTIONS

Both femoral nerves of six fresh cadavers were injected with either 20 ml or 40 ml of dye. The abdomen was opened and distribution of the dye was observed.

MEASUREMENTS AND MAIN RESULTS

In all of the cadavers studied there was no evidence of a femoral nerve sheath capable of conveying methylene blue dye to the lumbar plexus. Both 20 ml and 40 ml of dye injected into the femoral nerve failed to reach the lumbar plexus or the obturator nerve. When 40 ml of dye was injected it always stained the femoral nerves, it usually stained the lateral femoral cutaneous nerves, but it never stained the obturator nerves.

CONCLUSIONS

A femoral nerve sheath capable of conveying a solution to the cadaver lumbar plexus does not exist in human cadavers. Dye injected into the cadaver femoral nerve does not reach either the lumbar plexus or the obturator nerve. When 40 ml of methylene blue dye is injected into the cadaver femoral nerve, some dye usually diffuses under the iliacus muscle fascia to the lateral femoral cutaneous nerve. This study indicates that in patients the "3-in-1 block" always blocks the femoral nerve, it usually blocks the lateral femoral cutaneous nerve, but it probably does not block the lumbar plexus or the obturator nerve.

Paravascular lumbar plexus block: block extension after femoral nerve stimulation and injection of 20 vs. 40 ml mepivacaine 10 mg/ml

The goal of this prospective randomized study was to assess the extension of the "three-in-one" paravascular lumbar plexus block after femoral nerve stimulation and injection of 20 vs. 40 ml mepivacaine 10 mg/ml. Three-in-one blocks were achieved in 12 of 39 (31%) patients given 20 ml of 1% mepivacine (group 1), and 17 of 41 (41%) patients given 40 ml (Group 2) of the same solution (n.s.). The level of successful blockade at each nerve did not differ between groups. The femoral nerve was blocked in 92% vs. 93% of patients in groups 1 and 2, respectively; the obturator nerve in 62% vs. 78%; and the lateral cutaneous femoral nerve in 41% vs. 44%. We conclude that femoral nerve stimulation is effective in faciliating blockade in the femoral nerve but not the obturator or lateral cutaneous femoral nerve with the tested solution and volumes, and therefore not particularly effective for achieving complete 3-in-1 blockade. Within the clinically relevant range of 20-40 ml, the volume of mepivacaine 10 mg/ml does not appear to influence the extent of blockade.

A study into the incidence of methaemoglobinaemia after 'three-in-one' block with prilocaine

A 34-year-old female patient developed methaemoglobinaemia following a femoral nerve block using prilocaine. The concentrations of methaemoglobin in the blood of the next eight patients receiving this block were assayed, and found to be significantly increased above baseline concentrations, but very significantly less than the concentration in the patient with symptomatic methaemoglobinaemia. Pulse oximetry was of value in making the diagnosis.

Comparison of lumbar plexus block versus conventional opioid analgesia after total knee replacement

A randomised controlled study was undertaken to assess the analgesic efficacy of continuous lumbar plexus block for the first 48 hours after total knee replacement surgery. Boluses of 0.5% bupivacaine with adrenaline 1 in 200,000 (0.3 ml/kg) were administered through a cannula inserted into the neurovascular sheath of the femoral nerve. Thirteen patients who received this block required significantly less morphine than a control group of 16 patients. Pain scores were similar and there were no complications related to this technique.

Evaluation of local anaesthetic blockade of the lateral femoral cutaneous nerve

An assessment of local anaesthetic blockade of the lateral femoral cutaneous nerve using a standard technique was made. The rate of successful blockade was high, but the area of sensory loss was inconsistent between patients and was more anterior and distal than described in textbooks of anatomy.