Motor-sparing regional anaesthesia for lower limb burns: A novel combination of peripheral nerve blocks

Femoral nerve block is widely used for regional anesthesia and analgesia in many lower limb operations. Peripheral nerve stimulation of the femoral nerve may elicit 1 of 2 responses: contraction of the sartorius muscle through stimulation of its muscular branch or contraction of the quadriceps muscle through stimulation of its respective muscular branches. Historically, a quadriceps response has been preferred. We hypothesized that the success of femoral nerve block using a sartorius muscle evoked motor response is equivalent to that using quadriceps muscle twitch response. This prospective randomized double-blind controlled trial compared sartorius or quadriceps muscle evoked motor response as the end point for stimulation for femoral nerve block. Seventy-two patients scheduled for primary unilateral total knee arthroplasty were randomly assigned to undergo femoral nerve block using either the sartorius or the quadriceps evoked muscle response as an end point of stimulation. Motor block of the femoral and sensory block of the femoral, saphenous, and lateral femoral cutaneous nerves were assessed. The primary outcome was the quality of motor and sensory block of the femoral nerve 30 minutes after injection of 20 mL of 0.5% ropivacaine. Secondary outcomes were duration of femoral nerve block, time required to perform the nerve block, total dose of hydromorphone patient-controlled analgesia, and postoperative pain by visual analog score 24 hours after block insertion. In addition, the spread of local anesthetic and the position of the needle in relation to the femoral nerve were assessed by means of ultrasonography. There were no statistically significant differences in the proportion of patients with either complete alone or complete and partial block combined between quadriceps and sartorius groups 30 minutes after block insertion; femoral nerve (P = 0.49; P = 0.13), the saphenous nerve (P = 0.64; P = 0.21), or the lateral femoral cutaneous nerves (P = 0.2; P = 0.35). Patient-controlled analgesia hydromorphone consumption was significantly higher in the group that underwent sartorius muscle stimulation ([mean ± SD] 4.9 ± 3.6 mg [range, 0-13.2 mg] vs 3.1 ± 2.7 mg [range, 0-10.0 mg]; P = 0.024). Our study demonstrated that using sartorius or quadriceps evoked muscle twitch as an end point of stimulation was associated with an equivalent degree of femoral nerve block.

Magnetospinography provides a noninvasive and detailed visualization of neural currents. We previously reported that magnetospinography can be used to evaluate neural function in the lower lumbar spine in response to tibial, peroneal, and sciatic nerve stimulation. However, evaluating the neural function of the upper and middle lumbar spine is often difficult due to lower current intensity. We aimed to visualize the neural activity of the upper and middle lumbar spine using new stimulation methods and assess the foraminal current. Neural magnetic fields in 10 healthy volunteers were recorded after stimulation of the lateral femoral cutaneous nerve, saphenous nerve, femoral nerve, and peroneal nerve. The conduction velocity and current intensity in the spinal canal and intervertebral foramen were calculated and compared for each type of nerve stimulation. Magnetospinography visualized the evoked magnetic fields in the lumbar region after each nerve stimulation method in all volunteers. The current intensity in the upper lumbar spine was significantly greater after femoral nerve stimulation. Magnetospinography revealed that action current flowed mainly along the L2 nerve root after lateral femoral cutaneous nerve stimulation and the L4 nerve root after saphenous nerve stimulation. Using a new stimulation method, magnetospinography enabled the noninvasive visualization of neural currents in the upper and middle lumbar spine. Femoral nerve stimulation is suitable for evaluating the spinal canal of the upper lumbar spine, and lateral femoral cutaneous nerve and saphenous nerve stimulations are suitable for evaluating the upper and middle lumbar intervertebral foramina, respectively.

The extent of blockade when four different techniques were used for blocking the lumbar plexus was prospectively evaluated in 80 adult patients. The extent of blockade was measured by testing motor function of all nerves except the lateral and posterior femoral cutaneous nerves, which were evaluated by pinprick response. The posterior approaches of Dekrey at L3 (n = 20) and Chayen at L4-5 (n = 20) proved similarly effective in producing blockade of the femoral, obturator, and lateral femoral cutaneous nerves, as well as the nerves to the psoas muscle. The anterior approach of Winnie (femoral sheath or 3-in-1 block) using paresthesia (n = 20) or peripheral nerve stimulation (n = 20) proved effective in producing blockade of the femoral and lateral femoral cutaneous nerves, but ineffective for obturator nerve blockade. None of the four techniques produced blockade of the sacral plexus. Perhaps our means of assessing blockade (motor) is what produced the difference between our findings and those of others.

Landmarks for Peripheral Nerve Blocks Upper and Lower Extremities

<h3></h3> Neuropathic pain after surgery and trauma can be severe and debilitating and lead to low quality of life. The frequency of persistent neuropathic pain after surgery and trauma is...

ESRA19-0697 Knee arthroscopy and ligament repair: RA or infiltration

Background: The fascia iliaca compartment block is commonly used for postoperative analgesia after hemiarthroplasty. However, the method often fails to adequately manage pain due to frequent sparing of the lateral femoral cutaneous nerve. This randomised controlled study was conducted to compare the efficacy of lateral femoral cutaneous and femoral nerve blocks compared to fascia iliaca compartment block for postoperative pain management following hemiarthroplasty. Methods: Sixty patients were randomly assigned to either the fascia iliaca compartment (FIC) block group or the lateral femoral cutaneous nerve and femoral nerve (LFCN plus FN) block group. All patients received a subarachnoid block for surgery. Pain was assessed using a visual analogue scale (VAS) in the recovery room. When patients reported VAS score 3 or 4, the FIC and LFCN plus FN blocks were performed according to group allocation. VAS scores were reassessed 20 minutes after the blocks and recorded. Subsequently, the pain was assessed using VAS at two-hour intervals until the patients required rescue analgesia. Results: The VAS scores differed significantly between the two groups. In the LFCN plus FN block group, 13.3% reported VAS 0, 30% reported VAS 1, and the rest reported VAS 2. In the FIC block group, 53.3% reported VAS 2, and 46.7% reported VAS 3. None reported VAS 0 in the FIC group. The average time to demand rescue analgesia was 4.9 (0.8) hours in the FIC group and 9.4 (1.5) hours in the LFCN plus FN group. Adjusted time based on age, sex, body mass index, and Anesthesiologists class for the FIC block group was 6.8 (0.9) hours, while the LFCN plus FN block group recorded 7.5 (0.8) hours (P=0.003). Conclusion: Administering the LFCN and FN block separately but simultaneously provides better postoperative analgesia than the conventional FIC block following hemiarthroplasty.

Ultrasound-guided Nerve Blocks for Post-hernia Repair Pain

Regional block of the lateral femoral cutaneous nerve (LFCN) often has disappointing success rates despite the large volumes of local anesthetic used. This study was undertaken to investigate the utility of using a nerve stimulator (NS) to localize and block the LFCN. After obtaining institutional approval and informed consent, the authors proceeded with a two-stage study. In stage 1, 20 ASA 1 volunteers underwent LFCN block by both a fan and a NS technique in a prospective, randomized, crossover study utilizing strict criteria for success and extent of block. To predict clinical utility, 20 patients underwent LFCN block by the NS technique using the same assessment criteria (stage 2). Statistical analysis for the comparisons was completed employing the Fisher's exact or paired t-test as appropriate. P < .05 was considered significant. The NS technique significantly improved the success of LFCN block over the fan technique (100% vs. 40%, P = .00002). The extent of successful blocks was no different with the two techniques. Success in stage 2 was similar to that in stage 1 (85%) predicting clinical utility. A NS can be used to localize a purely sensory nerve; such as the LFCN, and improve success rates in regional anesthesia.

Analgesic strategies for day-case knee surgery.

SP19 Relevance of cutaneous nerve blocks

Cutaneous nerve entrapment plays an important role in neuropathic pain syndrome. Due to the advancement of ultrasound technology, the cutaneous nerves can be visualized by high-resolution ultrasound. As the cutaneous nerves course superficially in the subcutaneous layer, they are vulnerable to entrapment or collateral damage in traumatic insults. Scanning of the cutaneous nerves is challenging due to fewer anatomic landmarks for referencing. Therefore, the aim of the present article is to summarize the anatomy of the limb cutaneous nerves, to elaborate the scanning techniques, and also to discuss the clinical implications of pertinent entrapment syndromes of the medial brachial cutaneous nerve, intercostobrachial cutaneous nerve, medial antebrachial cutaneous nerve, lateral antebrachial cutaneous nerve, posterior antebrachial cutaneous nerve, superficial branch of the radial nerve, dorsal cutaneous branch of the ulnar nerve, palmar cutaneous branch of the median nerve, anterior femoral cutaneous nerve, posterior femoral cutaneous nerve, lateral femoral cutaneous nerve, sural nerve, and saphenous nerve.

Chapter 3 - Lower Limb Nerve Supply

BackgroundPericapsular nerve group (PENG) block is a novel technique that provides analgesia in hip surgeries while preserving motor function. This study aimed to identify developmental differences and variations regarding PENG block sonoanatomy in the inguinal region in children.MethodsA total of 150 children between 28 days and 18 years were included in this prospective, observational, descriptive study. The participants were divided into six groups according to growth and development periods. Ultrasonographic measurements representing block depth, needle length, and the vicinity of femoral nerve (FN) and femoral artery (FA) to the block area were collected.ResultsBlock depth: 16.2 ± 4.0 mm in infants (28 days–12 months); 33.5 ± 6.1 mm in adolescents (145–215 months). Needle length: 24.2 ± 5.9 mm in infants; 39.3 ± 6.6 mm in adolescents. The distance of FA to the block area: 4.4 ± 2.0 mm in infants; 11.6 ± 5.7 mm in adolescents. The distance of FN to the block area: 0.7 ± 0.8 mm in infants; 2.9 ± 4.0 mm in adolescents. FN-FA distance: 2.2 ± 1.4 mm in infants; 3.8 ± 1.8 mm in adolescents. In 49/150 (32.7%) cases the FN overlapped the perpendicular line between iliopsoas notch and skin. The lateral femoral cutaneous nerve (LFCN) was involved in the ultrasound frame in 11/50 (22%) children under the age of three.ConclusionsEspecially in children under three years of age, LFCN should be visualized during the pre-block preparation phase. The out-of-plane approach is not recommended in the PENG block due to the FN's alignment on the path of a vertical needle trace.Trial registrationNCT04860479.

Nerves of the leg and foot