Inadvertent Femoral Nerve Impalement and Intraneural Injection Visualized by Ultrasound

"Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part C (Prevention of Nerve Injuries)

"A clever person solves the problem. A wise person avoids it" (Albert Einstein). There is no convincing evidence that any modality 100% effectively prevents nerve injury. The risk of nerve injury remains the same even with the ultrasound due to limitations in the resolution of images and inter-operator and inter-patient differences. In a nutshell, caution is required when dealing with precious nerves in the perioperative period, either during peripheral nerve blocks (PNBs), patient positioning, or surgery. Identifying pre-existing nerve injury, either due to trauma or an existing neuropathy, and preventing further nerve injury should be an important goal in providing safe regional anesthesia (RA). Multimodal monitoring is key to avoiding multifactorial nerve injuries. The use of triple guidance (ultrasound + peripheral nerve stimulator + injection pressure monitor) during PNBs further improves the safety of RA. The ultrasound helps in real-time visualization of the nerve, needle, and drug spread; the peripheral nerve stimulator helps confirm the target nerves; and the injection pressure monitor helps avoid nerve injury. Such multimodalities can also give the confidence to administer PNB without risk of nerve injury. This article is part of the comprehensive overview of the essential understanding of peripheral nerves before blocking them. It describes various preventive measures to avoid peripheral nerve injuries while administering PNBs. It will help readers understand the importance of prevention in each step to avoid perioperative PNIs.

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.

Iatrogenic femoral nerve injuries: Analysis of medico-legal issues through a scoping review approach

Purpose

Accidental femoral nerve injury is a well-known iatrogenic complication of orthopaedic, abdominal, and pelvic surgery. Because of the largely transitory nature of the symptoms associated with nerve damage, its true incidence is in all likelihood underestimated. This work aims to illustrate the surgical contexts within which this nerve injury is reported, based on the evidence obtained from a Scoping Review of the literature of the last 20 years, with specific reference to the underlying etiopathogenetic mechanisms and prognostic outcomes, to highlight the evaluation issues of medico-legal interest related to this pathology.

Methods

We conducted a Scoping Review of iatrogenic femoral nerve injuries reported between 2000 and 2021 by searching the electronic databases Pubmed, Scopus, Ovid Medline, Ovid Emcare, and Web of Science.We conducted the review according to the five-step methodology outlined by Arksey and O'Malley.

Results

The literature search identified 104 papers, including case reports, case series, and retrospective studies. Surgical contexts within which iatrogenic femoral nerve injuries were reported include orthopaedic, abdominal, gynaecological, urological, vascular, and plastic surgery, as well as locoregional anaesthesiological procedures. The long-term prognosis was generally favourable.

Conclusions

Because of its frequent iatrogenic genesis, femoral nerve injury is a topic of intense medico-legal interest. From the perspective of estimating the patient's disability, the mostly favourable nature of the prognosis makes the medico-legal assessment, in some respects, complex, thus requiring a precise evaluation methodology.

A unique case of hoarseness of voice following left supraclavicular brachial plexus block

Hoarseness of voice following supraclavicular brachial plexus block is a rare complication and is seen in 1.3% of cases. It has been reported in cases of right supraclavicular brachial block exclusively. The reason for this is the course of recurrent laryngeal nerve which is not the same in the left and right sides. Here we report a case of left supraclavicular brachial plexus block following which the patient developed hoarseness of voice.

Regional Nerve Blocks-Best Practice Strategies for Reduction in Complications and Comprehensive Review

PURPOSE OF REVIEW

Understanding the etiologies of the complications associated with regional anesthesia and implementing methods to reduce their occurrence provides an opportunity to foster safer practices in the delivery of regional anesthesia.

RECENT FINDINGS

Neurologic injuries following peripheral nerve block (PNB) and neuraxial blocks are rare, with most being transient. However, long-lasting and devastating sequelae can occur with regional anesthesia. Risk factors for neurologic injury following PNB include type of block, injection in the presence of deep sedation or general anesthesia, presence of existing neuropathy, mechanical trauma from the needle, pressure injury, intraneural injection, neuronal ischemia, iatrogenic injury related to surgery, and local anesthetic neurotoxicity. The present investigation discusses regional blocks, complications of regional blocks, risk factors, site-specific limitations, specific complications and how to prevent them from happening, avoiding complications in regional anesthesia, and the future of regional anesthesia.

In-plane three-step needle insertion technique for ultrasound-guided continuous femoral nerve block after total knee arthroplasty: a retrospective review of 488 cases

BACKGROUND

Continuous femoral nerve block (CFNB) improves postoperative analgesia after total knee arthroplasty (TKA). The aim of this study was to investigate the clinical efficacy and complications of our in-plane three-step needle insertion technique that was devised to reduce the risk of direct femoral nerve injury during CFNB in anesthetized patients.

METHODS

This retrospective study included 488 patients who had undergone TKA. Ultrasound (US)-guided CFNB was performed under general or spinal anesthesia using an in-plane, three-step needle insertion technique. The success rate and difficulties of catheter placement, clinical efficacy of analgesia, and complications were recorded.

RESULTS

Femoral catheters were placed with a 100% success rate. In 488 patients, real-time US imaging revealed easy separation of the fascia iliaca and the femoral nerve following injection of local anesthetic through a Tuohy needle. Verbal numerical rating scale pain scores (0-10) were 2.0 ± 1.2, 3.5 ± 1.9, 3.2 ± 1.7, 2.9 ± 1.3, and 2.5 ± 1.1 at 1, 6, 12, 24 and 48 h postoperatively. No femoral hematoma, femoral abscess, or neurologic complications, including paresthesia or neurologic deficits, were observed during the 8-week follow-up period.

CONCLUSIONS

This retrospective study suggests that an in-plane three-step needle insertion technique for CFNB may reduce the risk of femoral nerve injury in anesthetized patients.

Neurotoxicity of perineural vs intraneural-extrafascicular injection of liposomal bupivacaine in the porcine model of sciatic nerve block

Liposomal bupivacaine is a prolonged-release local anaesthetic, the neurotoxicity of which has not yet been determined. We used quantitative histomorphometric and immunohistochemical analyses to evaluate the neurotoxic effect of liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in pigs. In this double-blind prospective randomised trial, 4 ml liposomal bupivacaine 1.3% was injected either perineurally (n = 5) or intraneurally extrafascicularly (n = 5). Intraneural-extrafascicular injection of saline (n = 5) was used as a control. After emergence from anaesthesia, neurological examinations were conducted over two weeks. After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in longer sensory blockade than perineural (p < 0.003) without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.

Stress response in shoulder surgery under interscalene block, randomized controlled study comparing ultrasound guidance to nerve stimulation

Background:

Shoulder surgeries are known to cause moderate to severe pain. Many techniques have been used successfully to minimize that stress response including interscalene block. Ultrasound guided techniques are becoming widely spread and commonly used for regional anesthesia. The objective of the present randomized controlled study is to compare the ultrasound guidance with nerve stimulation for interscalene brachial plexus block (IBPB) regarding the effect on stress response.

Patients and Methods:

50 patients, American Society of Anesthesiologists physical status I, II, and III, undergoing shoulder surgery were enrolled in the current study. Group U patients (n = 25) received ultrasound guided IBPB and Group N patients (n = 25) received IBPB using nerve locator. IBPB was done under ultrasound guidance using the linear 13-6 MHz transducer of the SonoSite M-Turbo ultrasonic device. In both groups, venous blood samples to measure cortisol level and assess stress response as a primary outcome were collected.

Results:

The current study demonstrated that the stress response, as indicated by the cortisol level in blood, showed no significant difference in the preoperative blood level between Group U and Group N, as well as blood level after block and before skin incision. However, it differed significantly between the two groups postoperatively.

Conclusion:

The current study concluded that the use of ultrasound guidance for IBPB in shoulder surgeries offered a significant suppression of the stress response intraoperatively and postoperatively as indicated by the low cortisol level with less complications and easier technique compared to nerve location.

Anesthesia for Vascular access Surgery

The type of anesthesia chosen is an integral part of the decision-making process for arteriovenous access construction. We discuss the different types of anesthesia used, with emphasis on brachial plexus block, which is potentially safer than general anesthesia in this fragile patient population with end-stage renal disease. Brachial plexus block is superior to local anesthesia and enables the use of a tourniquet to minimize potential damage to the blood vessels during anastomosis using microsurgery techniques, and does not lead to the vasospasm that may be seen with local anesthesia. Regional anesthesia has a beneficial sympathectomy-like effect that causes vasodilation with increased blood flow during surgery and in the fistula postoperatively that may prevent early thrombosis and potentially improve outcome.

Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: a comparison between the out-of-plane versus the in-plane approaches

BACKGROUND

The optimal method of ultrasound-guided femoral nerve block (in-plane vs. out-of-plane) has not been established. We tested the hypothesis that the incidence of needle-nerve contact may be higher with out-of-plane than with in-plane needle insertion.

METHODS

Forty-four patients with hip fracture (American Society of Anaesthesiologists physical status I-III) were randomized to receive the femoral block with an out-of-plane approach (needle inserted at a 45-60° angle 1cm caudal to the midpoint of the ultrasound probe just above the femoral nerve) or with an in-plane technique (needle inserted 0.2-0.4 cm from the side of the probe lateral to the femoral nerve). Data collected included depth of needle insertion, response to nerve electric stimulation, and distribution of the injected volume in relation to the nerve (anterior vs. posterior, the latter assuming needle-nerve contact). The sensory block onset was tested at 20 min and block recovery and any neurologic symptoms were evaluated at 24h.

RESULTS

The incidence of needle-nerve contact was significantly higher with the out-of-plane approach (14/22 patients [64%]) than with the in-plane approach (2/22 patients [9%]) (p<0.001) (OR=17.5, 95% CI: 4-79). The rate of paraesthesia on crossing the fascia iliaca was similar in the two groups. All blocks uneventfully regressed; and no patient developed neurologic symptoms.

CONCLUSIONS

Under the conditions of our study, needle-nerve contact during femoral nerve block occurs frequently with the out-of-plane approach. An in-plane approach results in an equally effective femoral block and less incidence of needle-nerve contact.

Complications of peripheral nerve blocks

Complications of peripheral nerve blocks are fortunately rare, but can be devastating for both the patient and the anaesthesiologist. This review will concentrate on current knowledge about peripheral nerve injury secondary to nerve blocks, complications from continuous peripheral nerve catheter techniques, and local anaesthetic systemic toxicity.

Ultrasound-guided sciatic nerve block in infants and toddlers produces successful anesthesia regardless of the motor response

BACKGROUND AND OBJECTIVES

The primary objective of this study was to assess the success rate of ultrasound-guided sciatic needle placement regardless of the motor stimulation in infants and toddlers.

METHODS

Forty-five consecutive patients aged 7 months-2 years, scheduled for foot surgery, were included in this prospective, descriptive and blinded study. After induction of general anesthesia, sciatic nerve block was performed under ultrasound guidance in the subgluteal area using an insulated needle connected to a nerve stimulator, with the power off. At the precise point when it was presumed that the needle was touching the sciatic nerve, the peripheral nerve stimulator was turned on at 0.5 mA and the current was slowly decreased to 0.2 mA. Presence and location of any motor responses were observed and recorded. Statistical analysis was applied to compare the success rate in patients who did and did not exhibit a motor response to electrical stimulation. Postoperatively, block duration and analgesic consumption were recorded.

RESULTS

The sciatic nerve could be distinctly visualized in 44 children, and all these blocks were successful. Only 22% patients showed any motor response to electrical stimulation. There was no significant difference in block characteristics between patients who exhibited a motor response with electrical stimulation and those who did not.

CONCLUSION

Success rate of ultrasound-guided sciatic nerve block remains unaltered irrespective of motor response to neurostimulation.

Electron microscopy evaluation of block needle-related trauma to the tibial nerve

BACKGROUND

Direct puncture by a needle is a risk factor for nerve damage. This investigation used scanning electron microscopy (SEM) to attempt to visualize the damage caused by different needles.

METHOD

A 15 cm section of the tibial nerve was removed from the ankle of a patient undergoing below-the-knee amputation. The nerve specimen was punctured perpendicular to the fibers once by each of four needles: an insulated 22 G short-beveled (30 degrees), a 25 G long-beveled Quincke spinal needle, an 18 G Tuohy, and a 25 G Whitacre pencil point. The distal and proximal ends on either side of the needles were marked and the nerve was sectioned into 0.5 cm pieces. Each sample was preserved and then prepared for SEM. The needle tract was observed for evidence of mechanical damage at magnifications between x 47 and x 102 using SEM.

RESULTS

The epineurium, perineurium, fascicles, endoneurium, and vessels were identified in each sample. In both the short-beveled and the Whitacre samples, all fascicles along with the surrounding perineurium were intact. In both the Tuohy and the Quincke samples, obvious transection of fascicles and disruption of the perineurium were observed.

CONCLUSIONS

This investigation suggests that both the Tuohy and the Quincke needles may be more likely to cause trauma to the tibial nerve than either the short-beveled or the Whitacre needles.

Popliteal catheter placement utilizing ultrasound needle guidance system

While ultrasound (US)-guided placement of peripheral nerve blocks is rapidly gaining popularity, expert practitioners agree that two of the most significant barriers to safety and efficacy are keeping the needle tip within the image and unintentional probe movement during the procedure.1 In addition, placing a nerve catheter past the needle tip under direct US observation requires two practitioners: one to hold the US probe and needle and another to advance the catheter. We present a case of a needle guidance system that attaches to the ultrasound probe and facilitates in-plane imaging. It enables a single practitioner to successfully execute a popliteal sciatic nerve block and visualize catheter placement. Therefore, a needle guidance system may represent an additional modification to ultrasound imaging that increases both time efficiency as well as safety.

Ultrasound-guided nerve blocks: efficacy and safety

The introduction of affordable, portable and high-resolution ultrasound machines has rejuvenated interest in regional anaesthesia. The inherent benefits of direct visualisation of nerves and surrounding anatomy, continual observation of the needle tip and spread of local anaesthetic make ultrasound-guided regional anaesthesia highly appealing. However, in the cost-conscious health-care setting and to convince sceptics, there also needs to be evidence of increased benefits and reduced complications. Ultrasound is a rapidly developing area of technology and some of the newer modalities are discussed. This article focusses on the recent growing evidence to support the benefits of its use in nerve and plexus blocks. Common complications of nerve blocks can be avoided with ultrasound but have still been reported. Anatomical variants have been demonstrated by ultrasound and it has proved to be useful in performing regional anaesthesia in difficult situations or where peripheral nerve stimulation is unsuccessful or inappropriate.

Neurological complication analysis of 1000 ultrasound guided peripheral nerve blocks for elective orthopaedic surgery: a prospective study

Little data exists regarding the frequency of neurological complications following ultrasound guided peripheral nerve blockade. Therefore, we studied single injection and continuous ultrasound guided interscalene, supraclavicular, infraclavicular, femoral and sciatic nerve blocks in patients undergoing orthopaedic extremity surgery. All patients were contacted during postoperative weeks 2-4 and questioned for numbness or altered sensation anywhere in the involved extremity, and pain or weakness unrelated to surgery. The presumed aetiology of symptoms was based on the collective agreement of principal investigator, primary surgeon and a neurologist. Multivariate analysis was performed for characteristics potentially important in the causation of neurological complications. Of 1010 consecutive blocks, successful follow up between weeks 2 and 4 occurred in 98.6%. New, all-cause, neurological symptoms were present in 56/690 blocks (8.2%) at day 10, 37/1010 (3.7%) at 1 month and 6/1010 (0.6%) at 6 months. Most symptoms were due to causes unrelated to the block. Of 452 patients directly questioned at the time of the block, new neurological symptoms were more common in patients who experienced procedure-induced paraesthesia (odds ratio = 1.7, p = 0.029). The postoperative neurological symptom rate in this series is very similar to those previously reported following traditional techniques.

Structural injury to the human sciatic nerve after intraneural needle insertion

BACKGROUND

Recent clinical reports suggest that intraneural needle placement may not always lead to neurologic injury. To explain the absence of neurologic complications in these reports, we studied the risk and extent of nerve injury after intentional needle-nerve placement in a cryopreserved human sciatic nerve.

METHODS

The sciatic nerve was dissected from a cryopreserved cadaver through partial exposure. Needles were inserted through the nerve, using blunt-tip (30 degrees beveled) (group A) and sharp-tip (15 degrees beveled) (group D) needles. Five needle insertions were made for each needle type. Subsequently, transverse nerve sections at 10 needle trajectories were processed. Nerve samples were stained with hematoxylin-eosin, Masson trichromic, and immunohistochemical stains. In each section, the following variables were quantified: total number of fascicles and vessels in the immediate vicinity of the needle trajectories and the number of injured fascicles and vessels.

RESULTS

A total of 520 fascicles were quantified, of which 134 were in contact with the needle trajectories. The numbers of fascicles and vessels per section were 65 +/- 8 and 14 +/- 7, respectively. A mean of 16 +/- 5 fascicles were found in contact with the needle trajectory (group A: 17+/- 3, group D: 15 +/- 6). Of these, 4 fascicles (3.2%) and 1 intraneural vessel were found damaged in group D. No fascicular or vascular injuries were found in group A.

CONCLUSIONS

Our findings suggest that intraneural needle insertion may more commonly result in interfascicular rather than intrafascicular needle placement.

[Ultrasound guidance in pediatric regional anesthesia]

Ultrasound imaging is being used to guide pediatric nerve block procedures. Difficulties that arise because of the smaller anatomical structures in children can be compensated for by the greater aqueous consistency and reduced calcification. Given the shorter distance between the surface of the skin and nerves, it is advisable to use a linear array transducer working at a high frequency (7-10 MHz). Like adults, children benefit when ultrasound guidance is used in the performance of neuraxial nerve trunk blocks, particularly of the umbilical and ilioinguinal nerves, and in greater measure in spinal blocks. Ultrasound guidance enhances efficacy and also affords the important advantage of greater safety. The main disadvantages are the cost of equipment and the necessary learning curve.

[Portable ultrasound devices in regional anesthesia: the brachial plexus block]

Ultrasonography has received increasing attention in regional anesthesia in recent years because it allows visualization of the nerves, the needle, and the surrounding structures and makes it possible to monitor distribution of the local anesthetic. Ultrasound technology is unfamiliar to most anesthesiologists, unless they work with transesophageal echocardiography. Ultrasound-guided regional anesthesia relies entirely on the expertise of the person performing the technique and how that person interprets the images, though the latest portable ultrasound devices are ergonomically designed for fast, easy use, even by less experienced personnel. The high-frequency probes can identify the brachial plexus and produce excellent images of considerable educational value that differ only slightly from those provided by larger, more expensive equipment. Ultrasonography makes it possible to identify the brachial plexus, from the roots to the peripheral nerves of the arm. We describe the main approaches used in providing an ultrasound-guided brachial plexus block and explain the basic principles of ultrasound imaging.