Structural Injury to the Human Sciatic Nerve After Intraneural Needle Insertion
ABSTRACT 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.
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.
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.
Our findings suggest that intraneural needle insertion may more commonly result in interfascicular rather than intrafascicular needle placement.
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ABSTRACT: Intraneural puncture of local anaesthetics has been associated with permanent or transitory nerve injury. The use of ultrasound (US)-guided techniques for the blockade of peripheral nerves has revealed that intraneural puncture is a relatively common complication, which is not frequently associated with neurological deficits. In this study, 2.5 mL of lidocaine were administered using US-guidance into the sciatic nerve (ScN) of 12 piglets. The punctured nerves were sequentially evaluated by US (cross sectional area and relative echogenicity) before and immediately after the injections, and then at 1, 2, 4, 7 and 14 days. At these times, animals were euthanased two by two at each time point, and ScN samples were removed for histological examination. Cross sectional area and relative echogenicity values were statistically different immediately after the injections, returning to pre-puncture values within 4 days. The inflammatory process observed by histopathology showed a similar trend indicating that the integrity of the perineurium was maintained. Locomotor deficits were not observed. The increase in size of the ScN produced by the injection of lidocaine intraneurally did not induce motor deficits in piglets in the current study.The Veterinary Journal 04/2014; 200(1). DOI:10.1016/j.tvjl.2014.01.027 · 2.17 Impact Factor
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ABSTRACT: 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. 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 0.2-0.4cm 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 20min and block recovery and any neurologic symptoms were evaluated at 24h. 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. 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.12/2013; DOI:10.1016/j.redar.2013.09.023
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ABSTRACT: Ultrasound guidance is still a young method in regional anesthesia when compared to nerve stimulation and only a few studies exist comparing these two techniques in an axillary multiple injection approach. This prospective, randomized, observer-blinded study compared an ultrasound-guided (SONO) quadruple injection axillary block (out of plane, perineural) with a nerve stimulation-guided (STIM) triple injection axillary block for upper limb surgery. A total of 60 patients were randomized to either the SONO (n = 30) or STIM (n = 30) group. For the block 40-50 ml mepivacaine 1.5 % (plexus) and 5-10 ml mepivacaine 0.5 % (subcutaneous in the medial skin of the arm) was used. Anesthesia time was recorded as the primary end point. After evaluation of block-related pain using a visual analog scale (VAS) a blinded observer tested sensory and motor function of the median nerve (MED), ulnar nerve (ULN), radial nerve (RAD), musculocutaneous nerve of the upper limb (MUC) and medial cutaneous nerve of the forearm (CAM) at defined times. The main outcome variable was onset time (defined loss of sensory/motor function). No differences were observed between the groups in terms of onset time (single nerves 10-20 min, plexus 20-25 min) and success rate (SONO 90 %, STIM 89 %). Patient satisfaction as measured by block-related pain score (VAS 2 cm), complications (vascular puncture SONO 7 %, STIM 11 %; paresthesia SONO 21 %, STIM 22 %) and patient acceptance (SONO 92 %, STIM 91 %) showed no differences. Performance time was shorter in the SONO group (6.68 ± 1.72 min vs. 8.05 ± 2.58, p = 0.02). Nerve stimulation-guided axillary plexus blocks performed by trained anesthesiologists may result in similar onset times and success rates compared to ultrasound-guided blocks.Der Anaesthesist 05/2014; DOI:10.1007/s00101-014-2319-6 · 0.74 Impact Factor