Lumbar plexus block: an anatomical study

A Practical Guide to Lower Extremity Nerve Blocks for the Sports Medicine Surgeon

BACKGROUND

Peripheral nerve blocks (PNBs) are vital in the administration of surgical analgesia and have grown in popularity for use in lower extremity arthroscopic procedures because of their capacity to safely and effectively control pain. The number and specificity of PNBs, however, have made choosing the best option for a procedure nebulous for orthopaedic surgeons.

PURPOSE

To present a narrative literature review of the PNBs available for arthroscopic hip and knee procedures that is adapted to an audience of orthopaedic surgeons.

STUDY DESIGN

Narrative literature review.

METHODS

A combination of the names of various lower extremity PNBs AND "hip arthroscopy" OR "knee arthroscopy" was used to search the English medical literature including PubMed, Cochrane Library, ScienceDirect, Embase, and Scopus. Placement technique, specificity of blockade, efficacy, and complications were assessed. Searches were performed through May 2, 2021.

RESULTS

A total of 157 studies were included in this review of lower extremity PNBs. Femoral nerve, lumbar plexus, sciatic nerve, and fascia iliaca compartment blocks were most commonly used in arthroscopic hip surgery, while femoral nerve, 3-in-1, and adductor canal blocks were preferred for arthroscopic knee surgery. Each block demonstrated a significant benefit (P > .05) in ≥1 of the following outcomes: intraoperative morphine, pain scores, nausea, and/or opioid consumption. Combination blocks including the lateral femoral cutaneous nerve block, obturator nerve block, quadratus lumborum block, and L1 and L2 paravertebral block have also been described. Complication rates ranged from 0% to 4.8% in those administered with ultrasound guidance. The most commonly reported complications included muscular weakness, postoperative falls, neuropathy, intravascular and intraneural injections, and hematomas.

CONCLUSION

When administered properly, PNBs were a safe and effective adjuvant method of pain control with a significant potential to limit postoperative narcotic use. While blockade choice varies by surgeon preference and procedure, all PNBs should be administered with ultrasound guidance, and vigilant protocols for the risk of postoperative falls should be exercised in patients who receive them.

Ultrasound-guided peripheral abdominal wall blocks

The practice of regional anesthesia is in a state of progressive evolution, mainly due to the advent of ultrasound as an anesthesiologist's instrument. Alternative techniques for postoperative analgesia of abdominal surgeries, such as transversus abdominis plane block, oblique subcostal transversus abdominis plane block, rectus abdominis muscle sheath block, ilioinguinal and iliohypogastric nerve block, and quadratus lumborum plane block, have proven useful, with good analgesic efficacy, especially when neuroaxial techniques (spinal anesthesia or epidural anesthesia) are not possible. This review discusses such blockades in detail, including the anatomical principles, indications, techniques, and potential complications.

[Incidence of epidural spread after Chayen's approach to lumbar plexus block: a retrospective study]

BACKGROUND AND OBJECTIVES

The lumbar plexus block (LPB) is a key technique for lower limb surgery. All approaches to the LPB involve a number of complications. We hypothesized that Chayen's approach, which involves a more caudal and more lateral needle entry point than the major techniques described in the literature, would be associated with a lower rate of epidural spread.

METHOD

We reviewed the electronic medical records and chart of all adult patients who underwent orthopedic surgery for total hip arthroplasty (THA) and hip hemiarthroplasty due to osteoarthritis and femoral neck fracture with LPB and sciatic nerve block (SNB) between January 1, 2002, and December 31, 2017, in our institute. The LPB was performed according to Chayen's technique using a mixture of mepivacaine and levobupivacaine (total volume, 25 mL) and a SNB by the parasacral approach. The sensory and motor block was evaluated bilaterally during intraoperative and postoperative period.

RESULTS

A total number of 700 patients with American Society of Anesthesiologists (ASA) physical status I to IV who underwent LPB met the inclusion criteria. The LPB and SNB was successfully performed in all patients. Epidural spread was reported in a single patient (0.14%; p <0.05), accounting for an 8.30% reduction compared with the other approaches described in the literature. No other complications were recorded.

CONCLUSIONS

This retrospective study indicates that more caudal and more lateral approach to the LPB, such as the Chayen's approach, is characterized by a lower epidural spread than the other approach to the LPB.

Incidence of epidural spread after Chayen’s approach to lumbar plexus block: a retrospective study

Background and objectives

The lumbar plexus block (LPB) is a key technique for lower limb surgery. All approaches to the LPB involve a number of complications. We hypothesized that Chayen's approach, which involves a more caudal and more lateral needle entry point than the major techniques described in the literature, would be associated with a lower rate of epidural spread.

Method

We reviewed the electronic medical records and chart of all adult patients who underwent orthopedic surgery for Total Hip Arthroplasty (THA) and hip hemiarthroplasty due to osteoarthritis and femoral neck fracture with LPB and Sciatic Nerve Block (SNB) between January 1, 2002, and December 31, 2017, in our institute. The LPB was performed according to Chayen’s technique using a mixture of mepivacaine and levobupivacaine (total volume, 25 mL) and a SNB by the parasacral approach. The sensory and motor block was evaluated bilaterally during intraoperative and postoperative period.

Results

A total number of 700 patients with American Society of Anesthesiologists (ASA) physical status I to IV who underwent LPB met the inclusion criteria. The LPB and SNB was successfully performed in all patients. Epidural spread was reported in a single patient (0.14%;p < 0.05), accounting for an 8.30% reduction compared with the other approaches described in the literature. No other complications were recorded.

Conclusions

This retrospective study indicates that more caudal and more lateral approach to the LPB, such as the Chayen’s approach, is characterized by a lower epidural spread than the other approach to the LPB.

Fascia Iliaca Block as an Anesthetic Technique for: Acute Lower Limb Ischemia

Purpose

The purpose of this study is to evaluate the efficacy of preoperative fascia iliaca block (FIB) as a sole anesthetic technique in transfemoral thromboembolectomy of unilateral acute lower limb ischemia compared to unilateral spinal anesthesia (SA) as a primary outcome. Hemodynamic variation, postoperative pain score, and the first demand for analgesia with the total postoperative analgesic required in the 1^st postoperative day were considered as the secondary outcome.

Patients and Methods

This prospective randomized controlled study included two groups of patients aged between 40 and 70 years, who underwent transfemoral thrombectomy for acute unilateral lower limb ischemia. Patients in the spinal group (SA) (n = 56): underwent unilateral SA using 10 mg bupivacaine 0.5% and patients in the group FIB (n = 56): received FIB with 30 mL of 0.25% bupivacaine. Sensory block was evaluated over the incisional area with 3-point scale. If the sensory block did not reach zero grade after 30 min, the patient received general anesthesia.

Results

The incidence of the successful block was 100% in the SA group compared to 80.35% in the FIB group. There was a significant decrease in recorded heart rate and mean blood pressure within the SA group at 3, 10, and 20 min and 3, 20, and 45 min, respectively. Values of visual analog scale decreased significantly in SA group compared to that of the FIB group immediately and 1 h postoperative. However, the time for the first postoperative analgesic requirement and morphine consumption was comparable between the groups.

Conclusion

Preoperative FIB could be considered as a promising alternative anesthetic technique to SA with better hemodynamic parameters in patients undergoing transfemoral thrombectomy for acute lower limb ischemia. It could be also due to limited precautions considered the first choice over SA for patients on perioperative anticoagulants.

Anatomy and Anaesthesia of the Lumbar Somatic Plexus

Cadaveric dissection demonstrated the lumbar plexus to lie within the substance of psoas major, with the major branches of the lumbar plexus emerging into the psoas compartment adjacent to the L5 vertebra. Within psoas major, the lateral femoral cutaneous and femoral nerves were separated from the obturator nerve by a muscular fold in 36 of 60 plexuses. Anatomical variations were common, with the accessory obturator nerve being identified in 12 per cent of plexuses. All previously described lumbar plexus block approaches positioned the needle within close proximity to the lumbar plexus. Modifications to these approaches may increase efficacy and reduce complication rates.

Pneumoretroperitoneum after Attempted Epidural Anesthesia

Air may extend to the retroperitoneal space from retroperitoneal perforation of a hollow viscus, infection of the anterior pararenal space with gas-forming organisms and from pneumothorax or pneumomediastinum [1]. Rare pathologies, such as open reduction and internal fixation of femoral fractures and anaerobic abscess of the hip joint have also been described in relation to this complication [1,2]. A rare case of pneumoretroperitoneum caused by insufflation of air during an attempt to achieve epidural anesthesia is described.

The psoas compartment block for hip surgery: the past, present, and future

A posterior lumbar plexus block or psoas compartment block (PCB) is an effective locoregional anesthetic technique for analgesia and anesthesia of the entire lower extremity including the hip. Since the first description in the early seventies, this technique has been modified based on advanced knowledge of the anatomical localization of the lumbar plexus and the improvement of technical equipment. This paper provides an overview of the history, clinical efficacy, and risk profile of the PCB focused on hip surgery. Current status and future expectations are discussed.

A comparison of epidural anesthesia and lumbar plexus-sciatic nerve blocks for knee surgery

OBJECTIVES

The efficacy of combined lumbar plexus-sciatic nerve blocks was compared to epidural anesthesia in patients undergoing total knee surgery.

PATIENTS AND METHODS

The study included 80 American Society of Anesthesiologists (ASA) Physical Status I-III patients (age range 18 to 65) undergoing knee surgery. The patients were randomly divided into one of two groups. Epidural anesthesia was performed in the epidural anesthesia (EA) group (n=40), and the lumbar plexus and sciatic nerves were blockedin the lumbar plexus-sciatic nerve blocks (LPSB) group (n=40). For each patient, onset of sensory and motor block, degree of motor block, sign of sensory block in the contralateral lower limb for the lumbar plexus-sciatic nerve blocks group, success in providing adequate anesthesia, hemodynamic changes, time of first analgesic request, and patient and surgeon satisfaction with the anesthetic technique were recorded.

RESULTS

One patient in the epidural anesthesia group and three patients in the lumbar plexus-sciatic nerve blocks group required general anesthesia due to failed block. There were no significant differences between the two groups regarding the success of providing adequate anesthesia. Eight patients in the lumbar plexus-sciatic nerve blocks group developed contralateral spread. The onset of sensory-motor block and the time of the first analgesic request were significantly later in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group. Although there were no significant differences regarding patient satisfaction with the anesthetic technique between the two groups, surgeon satisfaction was significantly higher in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group.

CONCLUSION

The lumbar plexus -sciatic nerve blocks provide effective unilateral anesthesia and may offer a beneficial alternative to epidural anesthesia in patients undergoing total knee surgery.

[Psoas compartment block with general anaesthesia: descriptive study of 93 cases]

OBJECTIVES

During many years the approach to the lumbar plexus has been the anterior paravascular technique described as a "3-1" block by Winnie. The posterior approach results in a complete block of the principal nerves of the lumbar plexus. The goal of the study was to evaluate the performance of the psoas compartment block with general anaesthesia.

STUDY DESIGN

Prospective, descriptive, non randomized study.

PATIENTS AND METHODS

Ninety-three patients scheduled for hip surgery were studied after informed consent. Demographic data, technical aspects of the puncture, complications, and intra- and postoperative analgesics were recorded.

RESULTS

The block was performed by resident alone, senior alone, both in respectively 44%, 45, and 11% of cases. The mean duration of the procedure was 6+/-3 min for the residents, 5+/-2 min for the seniors, and 9+/-4 min for both. The transverse process was reach in 72% of cases during the first approach, after reorientation of the needle in the others cases, except 3 failures of attempt. The lumbar plexus was assessed within 60-90 mm of depth, with a median of 75 mm. The motor response was mainly a femoral response; the minimal intensity of stimulation was ranged between 0.3 and 1 mA, with a median of 0.6 mA. The duration of analgesic block was 16.5+/-4.5 hours, with a median of 18 hours. The morphine use during the first postoperative 24 hours was 8+/-8 mg, with a median of 5.6 mg. No neurologic complication was recorded at discharge from the hospital.

CONCLUSION

The psoas compartment block with general anaesthesia have shown it feasibility and efficiency on intra- and postoperative analgesia during hip surgery.

Lumbar plexus posterior approach: a catheter placement description using electrical nerve stimulation

IMPLICATIONS

The authors describe a modified technique of posterior approach to the lumbar plexus in the psoas compartment which allows nerve stimulation for the location of the plexus and catheter placement for extended-duration surgery and postoperative patient-controlled regional analgesia. A frequent incidence of total lumbar plexus block was observed.

Lumbar paravertebral nerve block in the management of pain after total hip and knee arthroplasty: a randomized controlled clinical trial

The accepted mode of pain management after total hip or knee arthroplasty is patient-controlled analgesia. This study evaluates the efficacy of lumbar paravertebral nerve block in diminishing postoperative pain when used as an adjunct to patient-controlled analgesia. A total of 115 arthroplasty patients received postoperatively a lumbar paravertebral nerve block (block, n = 57) or a sham procedure (control, n = 58). The block group required approximately 10 mg less morphine for pain control than the control group during the first 4 hours postoperatively (P<.001). There were no significant differences in morphine use between the groups 4 to 24 hours postoperatively. Visual analog scale pain score measurements at 4, 8, and 24 hours did not differ significantly between the groups. Paravertebral nerve block of the lumbar plexus is an invasive procedure with some risk. Considering the added risk and minimal benefits, routine use of this procedure is not supported.

Ultrasound guidance for the psoas compartment block: an imaging study

We conducted this study to develop an ultrasound-guided approach to the psoas compartment and to assess its feasibility and accuracy by means of computed tomography (CT). Two examiners performed ultrasound-guided approaches at three levels (L2-3, L3-4, and L4-5) on 10 embalmed cadavers, which were seated prone. After each needle had been advanced into the psoas compartment under ultrasound guidance, the positions of their tips were computed by using two coordinates (A and B). Subsequently, axial transverse CT scans were made to verify the ultrasound measurements by using the same coordinates. In total, 48 approaches were performed (Examiner 1, n = 20; Examiner 2, n = 28). CT revealed that 47 of 48 ultrasound-guided approaches were performed exactly. In 1 of 48 approaches (L3-4), the tip of the needle was located posterior to the psoas muscle. The median differences between ultrasound and CT coordinates were 0.3 plus minus 0.3 cm for A and 0.2 plus minus 0.3 for B. Kendall's coefficient of concordance was 0.9 (P < 0.001) between ultrasound and CT measurements for both coordinates. These results indicate that ultrasound enables exact needle placement, as proved by CT. We conclude that ultrasound guidance might be a useful adjunct to increase the safety and efficacy of the psoas compartment block at these levels.

IMPLICATIONS

We developed an ultrasound-guided approach to the psoas compartment at the levels L2-3, L3-4, and L4-5. Feasibility and accuracy were tested on embalmed cadavers and verified by means of computed tomography. Ultrasound guidance proved to be feasible and accurate for the performance of psoas compartment blocks.

A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block

IMPLICATIONS

We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.

[Total spinal anesthesia after posterior lumbar plexus block]

We report a case of total spinal anaesthesia which occurred after a lumbar plexus block using a posterior approach. After total hip arthroplasty under general anaesthesia, a lumbar plexus block was performed according to Winnie's landmarks at the L4 interspace using a nerve stimulator. Aspiration test for blood and spinal fluid were both negative, as well as a test dose of 3 mL lidocaine 2%-bupivacaine 0.5%. One minute after the injection of 27 mL of the same mixture, a complete anaesthetic block occurred with hypotension and loss of consciousness requiring intubation and controlled ventilation during 3h30, without sequelae. Lumbar plexus block using a posterior approach must be performed cautiously and a slow and fractionated injection of the full dose is recommended.

Radiographic findings of unilateral epidural block

In 236 consecutive lumbar epidural anesthesia patients, epidurography was performed in seven patients who developed unilateral loss of cold sensation to clarify the cause of unilateral block. Epidurography demonstrated the epidural catheter tip location in the anterior epidural space in four patients (57%) and in the transforaminal passage in three patients (43%). In all seven patients, successful bilateral epidural anesthesia was obtained by a second puncture using another catheter. Our results showed that the most frequent cause of unilateral epidural blockade was the misplacement of the catheter into the anterior epidural space.