Upper extremity regional anesthesia techniques: A comprehensive review for clinical anesthesiologists

Surgeries and chronic pain states of the upper extremity are quite common and pose unique challenges for the clinical anesthesiology and pain specialists. Most innervation of the upper extremity involves the brachial plexus. The four most common brachial plexus blocks performed in clinical setting include the interscalene, supraclavicular, infraclavicular, and axillary brachial plexus blocks. These blocks are most commonly performed with the use of ultrasound-guided techniques, whereby analgesia is achieved by anesthetizing the brachial plexus at different levels such as the roots, divisions, cords, and branches. Additional regional anesthetic techniques for upper extremity surgery include wrist, intercostobrachial, and digital nerve blocks, which are most frequently performed using landmark anatomical techniques. This review provides a comprehensive summary of each of these blocks including anatomy, best practice techniques, and potential complications.

Diagnosis of Hourglass-Like Constriction Neuropathy of the Radial Nerve Using High-Resolution Magnetic Resonance Neurography: A Report of Two Cases

Hourglass-like constriction neuropathy is a neurological condition caused by fascicular constriction of one or more peripheral nerves, unrelated to intrinsic or extrinsic compression. It is often neglected in clinical practice, and its diagnosis is challenging. Here, we report two cases of hourglass-like constriction neuropathy in the radial nerve diagnosed using high-resolution magnetic resonance neurography (MRN). Two men, aged 47 and 19 years, developed sudden weakness in the left wrist and finger extensors. They were diagnosed with radial neuropathy between the left mid-humerus level and the elbow joint, using the electrodiagnostic test. To evaluate the cause of the nerve lesion and the lesion location, high-resolution MRN was performed. Patient 1 showed an hourglass-like constriction of the left posterior interosseous nerve within the epineurium of the left radial nerve, 8.9 cm proximal to the lateral epicondyle. Patient 2 showed two focal constrictions of the left radial nerve, 8.0 and 6.9 cm proximal to the lateral epicondyle, respectively, and distal to the radial groove. Additionally, bull’s eye signs were observed juxta-proximal to constrictions of the left radial nerve. The findings were indicative of hourglass-like constriction neuropathy. Both of the patients underwent surgery. However, at the 6-month follow-up, their motor weakness showed no improvement. MRN can be beneficial for diagnosing hourglass-like constriction neuropathy and locating the lesion.

Lateral External-fixation Adjacent to Radial Nerve

Introduction The aim of our study was to describe the injury pattern and outcomes of active-duty subjects that underwent humeral external fixation and to determine if the placement of external fixator pins outside of the radial nerve safe zones is correlated with injury to the radial nerve. Materials and methods We examined all US Service members treated with humeral external fixation at our facility from June 2005 through June 2015. The mechanism of injury, injury pattern, location of external fixation application, pre- and postoperative radial nerve function, presence or absence of radial nerve transection from injury or external fixation, anatomic location of pins in relation to the radial nerve safe zone, and final radial nerve outcomes were recorded. We defined the proximal safe zone as 5 cm distal to the acromion to 14.8 cm proximal to the lateral epicondyle, and we defined the distal safe zone as the proximal 70% of the transepicondylar width of the humerus when projected proximally from the lateral epicondyle. Results  For our study, 123 patients were identified over our date range, and 16 subjects were included with documentation regarding nerve function/injury characteristics, appropriate radiographs, and active duty status. Around 80% of injuries resulted from a blast mechanism, and 80% of injury patterns included either an intraarticular or open fracture. The radial nerve safe zone was violated in 15 of the 16 subjects (94%). The one subject with a safe construct did not sustain a nerve injury. Complete preoperative documentation on nerve function was only available for half of the subjects. Two of five subjects known to have intact function prior to external fixation had a postoperative neurologic deficit (40%). Of eight subjects with unknown radial nerve function prior to external fixation, seven subjects had full nerve function at the final follow up, and one subject had partial sensory function only. Of the three subjects with impaired preoperative radial nerve function, two made a full recovery, and the third recovered sensory function only. Around 50% of all subjects required medical retirement. Conclusion External fixation of upper extremity injuries in combat is rarely absolutely indicated, often results in the placement of pins outside of the radial nerve safe zone, and is associated with up to a 40% incidence of radial nerve injury.

Surgically relevant anatomy of the axillary and radial nerves in relation to the latissimus dorsi tendon in variable shoulder positions: A cadaveric study

BACKGROUND

The purpose of this study was to define the relationship of the axillary and radial nerves, particularly how these are affected with changing arm position.

METHODS

Twenty cadaveric shoulders were dissected, identifying the axillary and radial nerves. Distances between the latissimus dorsi tendon and these nerves were recorded in different shoulder positions. Positions included adduction/neutral rotation, abduction/neutral rotation for the axillary nerve, adduction/internal rotation, adduction/neutral rotation, adduction/external rotation, and abduction/external rotation for the radial nerve.

RESULTS

Width of the latissimus tendon at its humeral insertion was 29.3 ± 5.7 mm. Mean distance from the latissimus insertion to the axillary nerve in adduction/neutral rotation was 24.2 ± 7.1 mm, the distance increased to 41.1 ± 9.8 mm in abduction/neutral rotation. Mean distance from the latissimus insertion to the radial nerve was 15.3 ± 5.5 mm with adduction/internal rotation, 25.8 ± 6.9 mm in adduction/neutral rotation, and 39.5 ± 6.8 mm in adduction/external rotation. Mean distance increased with abduction/external rotated 51.1 ± 7.4 mm.

CONCLUSIONS

Knowing the axillary and radial nerve locations relative to the latissimus dorsi tendon decreases the risk of iatrogenic nerve injury. Understanding the dynamic nature of these nerves related to different shoulder positions is critical to avoid complications.

Radial Plate Fixation of Distal Radius Fracture

Background: A radial incision with radial plate fixation for distal radius fracture has historically been avoided due to its risk to the superficial branch of the radial nerve (SBRN). With careful technique, it is possible to avoid injury to the SBRN, thereby minimizing the soft tissue injury associated with other approaches. We compare subjective and objective functional outcomes of radial plate fixation surgeries that we performed with those of dorsal and volar plate fixation in current literature. Methods: Patients at a single center who underwent radial plate fixation for an AO type A or AO type B distal radius fracture between December 2006 and December 2014 were enrolled in the study. Postoperative grip strength and 3-digit pinch strength were measured systematically in the injured and uninjured wrists. Patients also completed a Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire to assess subjective outcomes. Results: Thirty-six patients met our inclusion criteria and had available medical records. Postoperative grip strength in the injured wrist was significantly lowered-68% compared with the uninjured wrist. After subgroup analysis of dominant and nondominant wrist injuries, there was no significant difference in grip strength between injured and uninjured wrists. There was no significant decrease in postoperative 3-digit pinch strength in the injured wrist-89% compared with the uninjured wrist. The mean QuickDASH score for our study participants was 20.9. Conclusions: Radial plate fixation is an effective approach for distal radius fractures. Objective and subjective outcomes are noninferior to those of a dorsal or volar approach.

Strength-Duration Curves of Radial Nerve in Patients With Lateral Elbow Pain

CONTEXT

Lateral epicondylalgia (LE) refers to a painful condition at or around the lateral epicondyle of the humerus. LE is one of the most common injuries of the elbow; however, the cause of the pathology is not clear. Patients often experience symptoms consistent with a radial nerve injury; however, data on the involvement of the radial nerve are needed.

OBJECTIVE

To analyze the relationship between electrophysiologic excitability and morphology of the radial nerve in patients with unilateral chronic LE.

DESIGN

Cross-sectional study.

SETTING

Department of Physiotherapy, University of Seville.

PATIENTS

A total of 56 elbows (28 right, 28 left) in 28 patients (12 females, 16 males; age 49 [7.37] y) were recruited by convenience sampling.

MAIN OUTCOME MEASURES

Strength-duration curves (chronaxia and accommodation index) and cross-sectional area (CSA) of the radial nerve were made in all participants. All parameters were compared between both limbs. Also, pain with palpation in the lateral epicondyle and functional pain of involved extremities was assessed using visual analog scale and the Patient-Rated Tennis Elbow Evaluation, respectively.

RESULTS

Symptomatic limb showed higher CSA values of the radial nerve when compared with the asymptomatic limb (P < .001). On the symptomatic limb, duration of symptoms was positively correlated with CSA values. Chronaxia values were all normal and similar between both limbs (P = .35). Regarding accommodation index, 14 (54%) patients showed accommodation indices that suggested pathological radial nerve on the right limb, 4 (14%) on the left limb, 5 (18%) on both limbs, and 4 (14%) had none of the affected nerves. Eight-six percent of patients showed accommodation indices that suggested pathological radial nerve, independently of symptomatic limb. In these cases, affected nerves had higher CSA than the unaffected nerve (P = .01). On the affected nerves, duration of symptoms was positively correlated with accommodation indices.

CONCLUSIONS

These findings suggest that patients with unilateral chronic LE show a decreased excitability in any radial nerve, independently of the symptomatic limb, and that pathological nerves have higher CSA than the nonpathological nerves.

Safe zone for lateral pin placement for external fixation of the distal humerus

External fixation is a common, efficient technique used for humeral shaft stabilization and elbow fractures. There are reports of radial nerve injuries associated with this procedure. In this study, we investigated the course and variability of the radial nerve along the lateral humerus in relation to the elbow joint to determine a relatively safe zone for lateral pin placement in external fixation. Twenty upper extremities from 10 cadavers were studied. The nerve branches and course of the radial nerve along the lateral humerus were carefully dissected. Straight lines (a, b, and c) were made connecting three landmarks (the acromion, coracoid process, and anterior wall of the axilla) in the proximal upper extremity to the lateral condyle (LC) of the humerus; their intersections with the radial nerve (A, B, and C) were marked. We analyzed whether the intersection positions were correlated with the connecting line lengths. The mean lengths of the connecting lines were (a) 27.24 ± 2.57, (b) 26.18 ± 2.79, and (c) 20.95 ± 1.44 cm; the distance between the intersection points and the LC of the humerus were (Aa) 7.56 ± 1.31, (Bb) 6.90 ± 2.27, and (Cc) 5.01 ± 0.83 cm; and the measured intersection points of the radial nerve in the lateral aspect of the humerus were (A) 18.48%-34.82%, (B) 13.48%-40.00%, and (C) 19.27%-28.05% of the lengths of lines a, b, and c, respectively. Our data provide a more reliable reference to predict the course of the radial nerve on the lateral humerus and define a safe zone for pin placement. Clin. Anat., 33:637-642, 2020. © 2019 Wiley Periodicals, Inc.

Ipsilateral radial nerve, median nerve, and ulnar nerve injury caused by crush syndrome due to alcohol intoxication: A case report

RATIONALE

Autologous peripheral nerve injury caused by crush syndrome due to alcohol intoxication is relatively rare, and to our knowledge, the compression of 3 upper limb nerves at the same time has not been reported previously. If a compressive peripheral nerve injury is not treated in a timely manner, it is difficult to recover neurological function, and the prognosis is poor.

PATIENT CONCERNS

Here, we present a case of a 50-year-old man with ipsilateral radial nerve, median nerve, and ulnar nerve injuries caused by autogenous compression after drunkenness.

DIAGNOSIS

Electromyography and nerve conduction studies suggested peripheral nerve injury in the left upper limb. The diagnosis was injury to the radial nerve, median nerve, and ulnar nerve in the left upper arm.

INTERVENTIONS

Exploratory neurolysis surgery of the radial nerve, median nerve, and ulnar nerve was performed in the left upper arm. Postoperative oral neurotrophic drugs were administered, and functional exercise was performed.

OUTCOMES

After timely diagnosis and treatment, the strength of the left upper arm muscle recovered, and the prognosis of neurological function was satisfactory during 3 years of follow-up sessions.

LESSONS

In the treatment of such patients, a comprehensive understanding of their medical history and a strict physical examination should be performed. Combined with neuroelectrophysiological and imaging examination, the diagnosis can be confirmed. After timely diagnosis and treatment, the prognosis is mostly excellent.

"Triceps Brachii Muscle Response to Neurostimulation of the Radial Nerve during Axillary Plexus Blockade: Clinical, Anatomical and Histological Correlation"

Axillary plexus blockade is a common technique in clinical practice with a well-known pattern of structures around the brachial artery. Historically, the only proper response to radial nerve stimulation was considered to be extension of the hand and wrist. Twenty-five axillary blockades were assessed by ultrasound and neurostimulation; the principal objective was to correlate the needle position over the radial nerve with the anatomical and histological structure of that nerve. During the procedure, the needle was directed in two ways to reach the medial or lateral margin of the nerve: above the brachial artery or beneath it. Once the needle reached the nerve, the current was augmented gradually until a response was elicited. For the cadaveric anatomical study, eight axillae were dissected and histological samples were examined. The response of the triceps brachii muscle differed significantly between the two approaches to the radial nerve (P < 0.001), and the mean intensity of stimulation was significantly lower when the nerve was accessed above the artery (0.44 ± 0.15 mA) than below it (0.57 ± 0.17 mA) (P = 0.015). A triceps brachii motor response occurs at lower current intensity and lower needle-nerve distance when the radial nerve is accessed above the artery and over the latissimus dorsi tendon. These findings were correlated with the topography of the radial nerve in the axillary fossa. Clin. Anat. 33:578-584, 2020. © 2019 Wiley Periodicals, Inc.

CT Analysis of a Potential Safe Zone for Placing External Fixator Pins in the Humerus

BACKGROUND

Iatrogenic radial nerve injures are a common complication during the placement of external fixator pins at the lateral aspect of the humeral shaft. This study uses a three-dimensional measurement technique to locate a safe entry point for humeral pins when externally fixating the elbow. Methods: We fixed a guide wire to the radial nerve by a suture string, and used computed tomography (CT) to scan the upper limbs of cadaver specimens. Then, we measured the deviation angles of the radial nerve on the CT scans, and the distance from the radial nerve to the "elbow rotation center" (ERC). Result: The average distance from the radial nerve to the ERC was 87.3 ± 8.5 mm (range: 68-100 mm), 58.3 ± 11.3 mm (range: 32.12-82.84 mm), 106.3 ± 5.8 mm (range: 86.93-115.08 mm), and 113.9 ± 4.8 mm (range: 97.93-120.22 mm) at radial nerve deviation angles of 0°, -30°, 30°, and 45°, respectively. The average radial nerve deviation angle was -37.7° ± 7.7° and 123.9° ± 19.9° at 50 and 150 mm, respectively. Relative to 0°, the distance between the radial nerve and the ERC at radial nerve deviation angles of -30°, 30°, and 45° showed a significant difference (t = 18.20, p < 0.05; Z = 6.07, p < 0.001; Z = 6.40, p < 0.001, respectively). Conclusions: Pins inserted into the proximal humerus should be about 150 mm from the ERC with a radial nerve deviation angle of 30° anteriorly, and 50 mm from the ERC with a deviation angle of 30°-45° posteriorly.

Safe Zones for Cerclage Wiring of the Humeral Diaphysis

Cerclage wiring of the humeral diaphysis entails particular danger to the radial nerve and the deep brachial artery. We sought to delineate safe zones for minimally invasive cerclage wiring of the humeral diaphysis, specifically in relation to the radial nerve and accompanying vasculature. Cerclage wires were percutaneously inserted into three groups of fresh-frozen cadaveric humeri. Group 1-proximal midshaft humerus at 30% of humeral height (n = 4); Group 2-midshaft spiral groove at 45% of humeral height (n = 4); and Group 3-distal midshaft humerus at 60% of humeral height (n = 4). Subsequently, an extensive surgical exploration of the arteries and nerves around the humerus was performed, noting any disturbance to the vessels or nerves and measuring the distance from the cerclage wire to the radial nerve. Neurovascular structures were injured in 75% of specimens when the cerclage wire was inserted at the level of the spiral groove. Both posterior structures, e.g. the radial nerve and the deep brachial artery, and medial structures, e.g., the median nerve and brachial artery, were incarcerated. Application of the cerclage at 30% or 60% of humeral height did not cause neurovascular injury. Minimally invasive application of the cerclage wire at the spiral groove, which is at 45% of humeral height, is likely to cause injury to neurovascular structures. Application of the cerclage at the proximal or distal midshaft humeral areas is associated with less risk of such injury. Clin. Anat. 33:552-557, 2020. © 2019 Wiley Periodicals, Inc.

Innervation of wing membrane in Japanese little horseshoe bats, Rhinolophus cornutus

The spinal nerves supplying the wing membranes of Japanese little horseshoe bats, Rhinolophus cornutus were studied. The wing membrane was innervated by nerve branches of the radial, ulnar, and median nerves, showing that the membrane was formed from the skin of the forelimb rather than that of the thoracolumbar skin. The radial nerve was mainly composed of the ventral rami of C7–T1, the ulnar nerve by C8–T2, and the median nerve by C8–T1. These components of R. cornutus tended to be from a narrower range of spinal nerves and to position more caudally than those of humans. In addition, the ulnar nerve showed a distribution pattern different from that of other mammals.

The Anterior Approach for Transfer of Radial Nerve Triceps Fascicles to the Axillary Nerve

Nerve transfers are an increasingly popular method for surgical treatment of nerve injuries. One of the most popular of these is the transfer of radial nerve triceps fascicles to the axillary nerve. The most common approach for this transfer is the posterior approach, which gives excellent access to both nerves but is not easy to combine with other nerve transfers. We describe here an alternative, the anterior approach, that offers safe access to both radial and axillary nerves and has the added advantage of compatibility with approaches for other common nerve transfers.

Ultrasound in the Evaluation of Radial Neuropathies at the Elbow

There are five sites at which radial nerve entrapment at the elbow has been commonly reported. These include the level of the fibrous bands within the extensor carpi radialis brevis, the thickened fascial tissue at the radiocapitellar joint, the leash of Henry, the arcade of Frohse, and the distal border of the supinator muscle. This review describes the anatomy of the radial nerve at the elbow and the surrounding structures, and then provides an overview of the literature supporting the use of ultrasound to assist in the evaluation of suspected radial neuropathy at the elbow. This review concludes with a suggested ultrasonographic approach for the systematic evaluation of suspected radial neuropathy at the elbow.

In-plane and out-of-plane needle insertion comparison for a novel lateral block of the radial, ulnar, median and musculocutaneous nerves in cats

OBJECTIVE

To compare two needle insertion techniques in a novel lateral approach to the radial, ulnar, median and musculocutaneous (RUMM) nerve block in cat cadavers.

STUDY DESIGN

Prospective, cadaveric experimental study.

ANIMALS

A group of 18 feline cadavers.

METHODS

Cadavers were divided into two groups. Both thoracic limbs of each cat were 'blocked' using the 'in-plane' (IP) or 'out-of-plane' (OP) ultrasound (US)-guided method. A single operator with limited experience performed all the techniques. Cadavers were placed in lateral recumbency and the uppermost limb was injected before turning to 'block' the contralateral limb in the same manner. The IP method consisted of tracking the triceps brachii muscle until the radial (R) nerve could be identified in the same field of view as the ulnar, median and musculocutaneous (UMM) nerve bundle. A needle was guided by US towards the R nerve and subsequently, methylene blue (0.4 mL) was instilled adjacent to it. The needle was retracted and redirected to the UMM nerve bundle, and another 0.4 mL dye was instilled. For the OP technique, the limb was pronated at a 45° angle. The nerves were then identified with the R nerve directly above UMM nerves. A needle was directed OP deep towards UMM nerves and dye (0.4 mL) was instilled. The needle was retracted superficially and 0.4 mL dye instilled next to the R nerve. After dissection, the nerves were assessed and ≥6 mm of staining was considered a successful technique.

RESULTS

A total of 18 RUMM 'blocks' were performed IP and 18 were performed OP. The IP technique was more successful than the OP technique (R nerve p = 0.0339; UMM nerves p = 0.0352).

CONCLUSIONS AND CLINICAL RELEVANCE

The lateral approach to the RUMM was achievable in cat cadavers using both needle insertion techniques. The IP technique was significantly more successful than the OP technique.

Electrophysiological determinants of the clinical severity of axonal peripheral neuropathy

INTRODUCTION

Electrophysiological diagnosis of axonal peripheral neuropathy (PN) is based on the attenuated amplitudes of nerve conduction studies (NCS), or a reduced sural/radial amplitude ratio (SRAR). We aimed to identify the electrophysiological determinants of the clinical severity of PN.

METHODS

Patients with chronic axonal PN underwent detailed NCS. The clinical severity of PN was determined based upon the overall neuropathy limitations scale (ONLS).

RESULTS

Ninety-five patients (71.6% males, mean age 71.9 ± 9.0 years) were recruited. Significant correlations were observed between the radial sensory nerve action potential (SNAP) and the ONLS total score (Spearman's rho -0.382, p < 0.001); and between the tibial compound muscle action potential and the ONLS leg score (Spearman's rho -0.283, p = 0.005). No correlations between the SRAR and the ONLS scores were found.

DISCUSSION

The radial SNAP is the strongest electrophysiological determinant of PN severity and might be useful for monitoring disease progression or response to treatment. Muscle Nerve 59:491-493, 2019.

Relationship between the ulnar nerve and the branches of the radial nerve to the medial head of the triceps brachii muscle

One branch of the radial nerve to the medial head of the triceps brachii muscle (MHN) has been described as accompanying or joining the ulnar nerve. Mostly two MHN branches have been reported, with some reports of one; however, the topographical anatomy is not well documented. We dissected 52 upper limbs from adult cadavers and found one, two, and three MHN branches in 9.6%, 80.8%, and 9.6% of cases, respectively. The MHN accompanying the ulnar nerve was always the superior MHN. The relationship between the ulnar nerve and the MHN was classified into four types according to whether the MHN was enveloped along with the ulnar nerve in the connective tissue sheath and whether it was in contact with the ulnar nerve. It contacted the ulnar nerve in 75.0% of cases and accompanied it over a mean distance of 73.6 mm (range 36-116 mm). In all cases in which the connective tissue sheath enveloped the branch of the MHN and the ulnar nerve, removing the sheath confirmed that the MHN branch originated from the radial nerve. The detailed findings and anatomical measurements of the MHN in this study will help in identifying its branches during surgical procedures. Clin. Anat. 00:1-16, 2018. © 2018 Wiley Periodicals, Inc.

Compressive radial neuropathy by a synovial cyst during pregnancy: A clinical case report

RATIONALE

Compressive radial neuropathy by a synovial cyst in the radial tunnel during pregnancy is a rare occurrence. The management of radial nerve compression caused by a synovial cyst in a pregnant patient is a surgical dilemma owing to the fetal and maternal risks of treatment.

PATIENT CONCERNS AND DIAGNOSIS

A 37-year-old pregnant woman presented with progressive forearm pain at the gestational age of 12 weeks. A cyst was identified via musculoskeletal ultrasound and magnetic resonance imaging examinations in the radiocapitellar joint causing radial compressive neuropathy.

INTERVENTIONS

After regional nerve block and surgical removal of the cyst, the patient's forearm pain was alleviated without neurological deficits.

OUTCOME

symptoms from nerve compression were improved after surgical treatment LESSONS:: This report illustrates the case of a pregnant woman presenting a compressive neuropathy by an enlarged cyst possibly due to the unbalance of growth factors during pregnancy. With proper diagnosis and timely surgical intervention, such patients can achieve good neurologic recovery without maternal or fetal complications.

Radial Nerve F-wave reference values with surface electrodes from the anconeus muscle

INTRODUCTION

We sought to obtain normative values for radial nerve F-wave variables, recording with surface electrodes from the anconeus muscle.

METHODS

We tested 30 healthy participants (17 women, 13 men) and measured the following variables: number of F waves/40 traces (F%); minimum, maximum, and mean F-wave latency (FMIN, FMAX, FMED, respectively); F-wave chronodispersion (FCHR); interside differences of F% and FMIN (DF% and DFMIN, respectively).

RESULTS

The mean F% was 41.3%; the normative values of FMIN, FMED, FMAX, and FCHR were < 21.2, <22.1, <23.3, and < 4.0 ms, respectively; and normative values of DF% and DFMIN were < 16.6% and < 1.1 ms, respectively. Height was the sole independent predictor in a regression model of FMIN, FMED, and FMAX; this explained 37%-44% of the variability.

DISCUSSION

We identified a feasible and useful technique to record radial nerve F waves from the anconeus muscle and obtained normative values of F-wave variables. Muscle Nerve 59:244-246, 2019.

[Efficacy of surgical treatment by radial nerve transfer in patients with traumatic isolated axillary nerve injury]

PURPOSE

To determine the efficacy of surgical treatment by radial nerve transfer in patients with a diagnosis of isolated axillary nerve traumatic injury.

MATERIAL AND METHODS

We present a series of seven cases, six men and one woman, with a mean age of 51.6 years, with a diagnosis of isolated traumatic axillary nerve injury between January 2013 and December 2016. All patients were treated by radial motor branch nerve transfer of the medial triceps head between the sixth and seventeenth months after trauma, with a minimum follow-up of 12 months. The efficacy of the treatment was evaluated by the Medical Research Council (MRC) and the DASH questionnaire.

RESULTS

In the bivariate analysis we found statistically significant differences regarding the degree of external rotation and abduction strength measured by preoperative and postoperative MRC (p 0.05). The results also demonstrated a statistical significance in the range of postoperative shoulder abduction movement (p = 0.01). The DASH questionnaire showed an average percentage of disability of 20.29% after 12 months of follow-up.

CONCLUSION

Radial nerve transfer in patients diagnosed with axillary nerve traumatic injury provides an excellent degree of improvement in external rotation and abduction strength, in addition to significantly improving the shoulder abduction range, it was also demonstrated by DASH questionnaire that the percentage disability is low.

A Case Report of a Radial Nerve Palsy Following Uncomplicated Total Hip Arthroplasty

Introduction

Nerve injury is a known complication of total hip arthroplasty (THA), but it is most commonly seen in the lower extremities. There is, however, minimal discussion about the incidence of upper extremity nerve palsies, specific to the radial nerve, during THA for a patient in the lateral decubitus position. The radial nerve can be injured while in the lateral decubitus position due to poor positioning of the posterior part of the humerus onto the hard surgical table causing compression of the nerve. In THA, this is significant due to the lateral decubitus position being the primary position for the patient in posterior and lateral approaches. We report a case of radial nerve palsy following uncomplicated THA in the lateral decubitus position.

Case Report

A 49-year-old male presenting with symptoms of the left radial nerve palsy on post-operative day number one from a right (contralateral) THA. The patient has a body mass index of 22.15 and was undergoing a right THA with a posterior approach. He was placed in the lateral decubitus position with an axillary roll in place for approximately 2 h and 45 min. Occupational therapy, orthopedics, and electromyography were used to evaluate the patient in the post-operative time for his radial nerve palsy.

Conclusion

Our case report demonstrates a rare nerve palsy complication that can be associated with positioning in THA surgeries. Knowledge of this complication can be used to avoid pressure points in future THA surgeries in the lateral decubitus position.

Innervation of the Long Head of the Triceps Brachii in Humans-A Fresh Look

The triceps brachii muscle occupies the posterior compartment of the arm in humans and has three heads. The lateral and medial heads originate from the humerus and the long head arises from the infraglenoid tubercle of the scapula. All heads form a common tendon that inserts onto the olecranon and the deep antebrachial fascia on each side of it. Each head receives its own motor branch, which all are thought to originate from the radial nerve. However, several studies reported that the motor branch of the long head of the triceps (LHT) arises from the axillary nerve or the posterior cord. Here, we dissected 27 triceps in 15 cadavers to analyze the innervation of the LHT and found only radial innervation, which contradicts those studies. We examined studies reporting that the motor branch to the LHT in humans does not arise from the radial nerve as well as studies of the triceps in primates. Occasional variations of the innervation of skeletal muscles are normal, but a change of principal motor innervation from radial to axillary nerve has important implications. This is because the axillary nerve is often involved during shoulder injuries. The precise identification of the prevalence of axillary versus radial innervation is therefore clinically relevant for surgery, nerve drafting, and occupational and physical therapy. We conclude that the primary motor branch to the LHT arises from the radial nerve but axillary/posterior cord innervations occur occasionally. We suggest the development of a standard methodology for further studies. Anat Rec, 301:473-483, 2018. © 2018 Wiley Periodicals, Inc.

Humerus shaft fracture associated with traumatic radial nerve palsy: An international survey among orthopedic trauma surgeons from Latin America and Asia/Pacific

PURPOSE

The purpose of this article is to explore the real-life practice of clinical management of humeral shaft fracture associated with traumatic radial nerve palsy among orthopedic trauma surgeons.

METHODS

Two hundred seventy-nine orthopedic surgeons worldwide reviewed 10 real cases of a humeral shaft fracture associated with traumatic radial nerve palsy answering two questions: (1) What treatment would you choose/recommend: nonoperative or operative? (2) What are the reasons for your decision-making? The survey was developed in an online survey tool. All participants were active members from AOTrauma International.

RESULTS

Two hundred sixty-six (95.3%) participants were from Latin America and Asia/Pacific. One hundred sixty-two participants (58.1%) had more than 10 years in practice and 178 (63.8%) of them did trauma as the main area of interest. One hundred fifty-one (54.1%) participants treated less than three humeral shaft fractures a month. Traumatic radial nerve palsy was the main reason (88.4%) for surgeons to recommend surgical treatment. Open reduction and internal fixation (ORIF) or percutaneous fixation of the fracture associated with acutely explore of radial nerve was the first option in 62.0% of the cases. A combination of morphology and level of the fracture and the presence of the radial nerve palsy was the most suggested reason to surgically treat the humerus fracture. The main isolated factor was the morphology of the fracture.

CONCLUSION

Our survey highlight the tendency for a more aggressive management of any humeral shaft fracture associated with a traumatic radial nerve palsy, with surgeons preferring to use ORIF with acute exploration of the radial nerve. Nonsurgical management was the less chosen option among the 279 respondents. Fracture morphology, level of the fracture, and the presence of the radial nerve palsy were most influential for guiding their treatment.

The safety and feasibility of minimal invasive plate osteosynthesis (MIPO) of the posterior aspect of the humerus: A cadaveric study

The aim of this study was to determine the feasibility of applying MIPO of the humerus via the posterior approach and to observe the tension of the radial nerve in different elbow positions. Two separate incisions were made on the posterior aspect of the humerus in ten fresh cadavers (20 humeri). The radial nerve was identified at the proximal incision and the distances through which the nerve could be elevated from the bone with the elbow in flexion and extension were measured. A 10-hole extra-articular distal humeral locking compression plate was inserted and fixed through the submuscular tunnel. The tunnel was then explored to identify any entrapment of the radial nerve and to observe the anatomical relationship of the radial nerve to the plate and bone. There was no entrapment of the radial nerve or its branches. The distances through which the radial nerve could be elevated were greater with the elbow in extension than in flexion (P < 0.01). The radial nerve crossed the medial and lateral borders of the posterior surface of the humerus at 80.1-132 mm (average 104.7 mm) and 116.6-175.5 mm (average 142.7 mm) of its total length, respectively. The axillary nerve was located at 38.7-61.7 mm (average 47.9 mm) of total humeral length. MIPO of the humerus using the posterior approach is an alternative option for treating distal humeral shaft fracture. The risk of radial nerve injury can be minimized by careful dissection in the proximal incision. Clin. Anat. 32:176-182, 2019. © 2018 Wiley Periodicals, Inc.