Extensor Carpi Radialis Brevis Research Articles

Botulinum Toxin in Chronic Lateral Epicondylitis, from Tendon to Muscle Approach-A Review.

Chronic lateral epicondylitis challenges the therapeutical approach; underlying mechanisms are incompletely understood; neuropathic pain and central and peripheral sensitization may explain the fact that botulinum toxin has been found to play a role in pain and function management. We searched the literature for MeSH terms: lateral epicondylitis or synonyms and botulinum toxin. We found 14 papers containing trials on botulinum toxin injection into the tendon or into the extensor muscles (specifically, extensor carpi radialis brevis and extensor communis digitorum). We followed the administration pathways, doses, timing, and side effects. With a chronic course, the focus of the therapy shifts from the afflicted tendon to the inserting muscles, as muscle contracture may create a vicious loop to perpetuate and aggravate the disease. Doses, timing, and side effects are discussed.

Comparison of two different orthoses used in the treatment of lateral epicondylitis.

Lateral epicondylitis (LE) is one of the most common causes of lateral elbow pain, and orthoses are often used in its conservative treatment. However, the number of studies examining the effectiveness of the orthoses used and their differences compared to each other is limited. To determine the effects of 2 orthoses types, wrist orthosis (WO) and counterforce brace (CB), commonly used in the treatment of lateral epicondylitis on muscle activation, grip strength, hand function, and satisfaction level in healthy individuals. Quasi-experimental study. Thirty-seven healthy individuals were recruited. Muscle activation was evaluated by surface electromyography, and maximum grip strength was evaluated with a handheld dynamometer. Hand function and satisfaction level were evaluated with Jebsen Taylor Hand Function Test and Orthotics and Prosthetics Users Survey, respectively. All evaluations were conducted for each individual in 3 conditions (no orthosis, WO, and CB). Extensor carpi radialis (ECR) muscle activation was greater when using CB compared with that when without orthosis (p = 0.036). There was no significant difference in extensor digitorum communis (EDC) muscle activation and maximum grip strength among the conditions (p > 0.05). Hand function was worse when using the WO compared with the other conditions (p < 0.001). In terms of orthosis satisfaction, individuals were found to be significantly more satisfied with the use of CB (p = 0.001). In our study highlight the use of CB in terms of EDC muscle activity, grip strength, hand function, and satisfaction, while the use of WO is prominent in terms of keeping extensor carpi radialis muscle activity low, which has been shown to be important for LE. To obtain definitive results on the effectiveness of different orthoses in the treatment of LE, more research is needed to compare the muscular activation in the extensor carpi radialis brevis (ECRB) and EDC muscles with objective methods.

Adaptive HD-sEMG decomposition: towards robust real-time decoding of neural drive.

Objective. Neural interfacing via decomposition of high-density surface electromyography (HD-sEMG) should be robust to signal non-stationarities incurred by changes in joint pose and contraction intensity.Approach. We present an adaptive real-time motor unit decoding algorithm and test it on HD-sEMG collected from the extensor carpi radialis brevis during isometric contractions over a range of wrist angles and contraction intensities. The performance of the algorithm was verified using high-confidence benchmark decompositions derived from concurrently recorded intramuscular electromyography.Main results. In trials where contraction conditions between the initialization and testing data differed, the adaptive decoding algorithm maintained significantly higher decoding accuracies when compared to static decoding methods.Significance. Using "gold standard" verification techniques, we demonstrate the limitations of filter re-use decoding methods and show the necessity of parameter adaptation to achieve robust neural decoding.

Efficacy of PowerBall Versus Mulligan Mobilization With Movement on Pain and Function in Patients With Lateral Epicondylitis: A Randomized Clinical Trial.

Background Lateral epicondylitis (LE), sometimes referred to as tennis elbow or lateral elbow tendinopathy (LET), is one of the most common repetitive stress disorders in the elbow joint. Often, this involves the attachment of the extensor carpi radialis brevis muscle. This study's primary focus is on treating people with LE, a condition that causes repetitive movements of the upper extremities. There is currently no research on how PowerBall gadget workouts affect the function and pain of individuals with lateral epicondylitis. Exercises using the "PowerBall device," which appliesboth intrinsic and extrinsic pressure to the wrist, elbow, and shoulder muscles, are thought to be beneficial forms of resistance training. It has been shown that there are improvements in strength, function, range of motion (ROM), discomfort, and quality of life (QOL). On the other side, it has been demonstrated that LE patients have reduced discomfort while using Mulligan Mobilization with Movement (MMWM). Methods The 50 patients with LE were split into two groups for the single-blinded, randomized clinical study after baseline assessment and randomization: Group A was the intervention group, and Group B was the conventional group. The "PowerBall device" exercise was provided to participants in Group A, and MMWM was given to those in Group B. Both groups can benefit from basic workouts and ultrasonography by following the prescribed routine. Quantification of pain, function, grip strength, and range of motion was done at the start and finish of therapy using the Visual Analogue Scale (VAS), Patient Rated Tennis Elbow Evaluation (PRTEE), portable dynamometer, and goniometer. Results After therapy, both groups showed considerable improvement (p<0.05). Both descriptive and inferential statistics were employed in the data analysis. Numerous statistical tests were employed, such as the student's paired and unpaired t-test and the chi-square test. From a statistical and clinical perspective, Group A's outcomes were more significant. On the visual analog scale, there was a decrease in pain intensity for wrist and elbow mobility at rest (p<0.0003), activity (p<0.003), PRTEE (p<0.001), grip strength (p<0.03), and range of motion (p<0.01). Both groups' assessments after rehabilitation indicated increases in pain and function; however, Group A (0.03) benefited more and saw early success with the PowerBall device. Conclusion Findings show that a three-week program incorporating resistance training exercises mediated by a "PowerBall device" enhances upper limb performance beyond traditional exercise treatment and increases grip strength, wrist extension strength, internal and external rotator concentric and eccentric strength. The findings and observations indicate that both groups have significantly improved.

Surgical Technique: Brachioradialis to Extensor Carpi Radialis Longus and Brevis Nerve Transfers for Tetraplegia.

Improving upper extremity function in high cervical spinal cord injury (SCI) patients with tetraplegia is a challenging task owing to the limited expendable donor muscles and nerves that are available. Restoring active wrist extension for these patients is critical because it allows for tenodesis grasp. This is classically achieved with brachioradialis (BR) to extensor carpi radialis brevis (ECRB) tendon transfer, but outcomes are suboptimal because BR excursion is insufficient and its origin proximal to the elbow further limits the functionality of the tendon transfer, particularly in the absence of elbow extension. As an alternative approach to restore wrist extension in patients with ICSHT group 1 SCI, we present the first clinical report of the BR to extensor carpi radialis longus (ECRL) and BR to ECRB nerve transfers.

Anconeus Muscle Transfer to Correct or Prevent Wrist Radial Deviation in Radial and Posterior Interosseous Nerve Injuries

Wrist radial deviation is a possible complication of tendon transfer for restoration of wrist extension in cases of radial nerve paralysis. In posterior interosseous nerve (PIN) injury, this is because of the imbalance caused by the intact extensor carpi radialis longus and paralysis of the extensor carpi ulnaris (ECU). This deformity may also occur following transfer of the pronator teres (PT) to the extensor carpi radialis brevis (ECRB) for radial nerve palsy. To address wrist radial deviation, we propose transferring the anconeus muscle, extended by the intermuscular septum between the ECU and the flexor carpi ulnaris (FCU), to the ECU tendon. Through an incision over the ulna, the intermuscular septum between the ECU and FCU is harvested at the level of the periosteum and left attached to the anconeus proximally. The anconeus muscle is then released from the ulna, and the intramuscular septum extension is sutured to the ECU tendon under maximal tension. Anconeus muscle transfer was performed on two patients to correct chronic wrist radial deviation following PT to ECRB tendon transfer for radial nerve injury, as well as on two patients with PIN paralysis. In four patients, transfer was performed in addition to standard tendon transfers for radial nerve paralysis to prevent radial wrist deviation deformity. Wrist radial deviation was corrected or prevented in all but one patient at an average follow-up of 10 months. Patients with PIN lesions and those who had anconeus transfer concomitantly with radial nerve tendon transfers were capable of active ulnar deviation. No patient experienced elbow extension weakness, pain, or instability. Anconeus muscle transfer extended by intermuscular septum presents a viable alternative for addressing radial deviation of the wrist in cases of PIN nerve lesions or following PT to ECRB tendon transfer in radial nerve paralysis. Therapeutic V.

Alteration of Interhemispheric Inhibition in Patients With Lateral Epicondylalgia

Patients with lateral epicondylalgia (LE) show alterations in the primary motor cortex (M1) contralateral to the affected side. Cortical alterations have been investigated by measuring intracortical facilitation/inhibition; however, their association with pain remains controversial. Furthermore, no studies have investigated changes in interhemispheric inhibition (IHI). IHI can be assessed using the ipsilateral silent period (iSP) known as the temporary inhibition of electromyographic activity evoked by transcranial magnetic stimulation in the ipsilateral M1 of the contracting muscle. To better understand the relationship between cortical alterations and pain in LE, this observational study investigated the relationship between iSP and pain in LE. Twenty-seven healthy volunteers and 21 patients with LE were recruited. The duration of iSP in the extensor carpi radialis brevis was measured. The IHI asymmetry ratio was calculated to determine the IHI balance. Pain and disability were scored using the Japanese version of the patient-rated elbow evaluation. We observed increased inhibitory input from the ipsilateral M1 on the affected side to the contralateral M1 in LE. Additionally, the IHI balance correlated with pain severity. Hence, regulating imbalanced IHI can potentially decrease lateral elbow pain in LE. PerspectivePatients with lateral epicondylalgia (LE) experience persistent pain and cortical alterations. However, there is no established relationship between cortical alterations and pain. This study demonstrated that the interhemispheric inhibition (IHI) balance is correlated with pain. Regulating imbalanced IHI can potentially decrease lateral elbow pain in patients with LE.

The hypoalgesic effects of wrist extensors training with blood flow restriction in patients with lateral elbow tendinopathy: a study protocol for a cross-over randomized controlled trial

Background: Lateral elbow tendinopathy (LET) is a disabling overuse injury with a significant healthcare burden. Despite the fact that exercise interventions are considered the best recommended treatment option of LET, their effectiveness in reducing pain and improving function remains debatable. The aim of our study is to evaluate the immediate effects of a new method of exercise using blood flow restriction (BFR) on pain perception and pain-free grip strength in patients with LET. Methods: This study was designed as a cross-over randomized controlled trial. We will compare an intervention using wrist extensors training with (WET-BFR) to a control intervention using WET-without-BFR in patients with LET. All measurements will be taken by a blinded assessor pre- and post-intervention. Primary outcome measures will be the changes in pressure pain thresholds at the lateral epicondyle, extensor carpi radialis brevis, C4 vertebra and tibialis anterior. Secondary outcome measure will be the changes in pain-free grip strength ratio. Conclusions: New approaches are needed to improve the treatment outcomes in LET. Although BFR training was found more effective in improving function and treatment success than conventional training, the effects on pain intensity were poor. Our hypothesis is that using the best BFR practice guidelines for wrist extensors training might be more effective to reduce pain sensitivity compared with non-BFR training in patients with LET. The trial will provide new research data to inform clinical practice regarding the effects of using BFR training in the current patient group. Trial registration: University of West Attica ethics committee: 9150/01-02-2023, ClinicalTrials.gov: NCT05919914

Arthroscopic Extensor Carpi Radialis Brevis Muscle Resection for Chronic Elbow Lateral Epicondylitis

Recalcitrant elbow lateral epicondylitis presents a difficult challenge for both the patient and the doctor. Surgical treatment consists of open resection and debridement of the extensor carpi radialis brevis muscle. However, advances in arthroscopic surgery provide for a more elegant method. There are several comparative studies between arthroscopic and open treatment that have shown equivalent outcomes. There is no consensus on which treatment is better and no defined indications of when to choose one over the other. This article presents our technique for arthroscopic extensor carpi radialis brevis muscle resection.

Editorial: The effect of Cyriax method on the treatment of Lateral Elbow Tendinopathy

Lateral elbow tendinopathy (LET) is the most common chronic disease of the elbow joint [1], affecting almost 1-3% of the general [2, 3]. Its incidence increases with age and is highest in the 35-60 age group [2, 4]. Extensor carpi radialis brevis’ tendon is the most common structure affected by LET [5]. There is a continuous cycle of minor injuries and constant attempts to repair the damage, causing in progressive degeneration [6,7]. Consequently, a domino effect of changes occurs in the peripheral nervous system neurons, ultimately resulting to the sensitization of the central nervous system [3, 8]. Treatment for LET includes a wide variety of techniques, due to the complexity of the condition. Scientific evidence on the efficacy of the various techniques is of poor quality [9], which hampers the choice of the right therapeutic plan [10, 11]. The Cyriax method was empirically developed by James Cyriax as a therapeutic approach to connective tissue damage [12]. It is an inseparable combination of deep transverse friction (DTF) and Mill’s manipulation [13, 14]. This approach aims to the passive mobilization of soft tissues, preparing them to endure load. The regenerative process is boosted and the mobility of the damaged tissue is restored through pain reduction [12, 14]. Despite the fact that clinical experience supports the use of Cyriax method on LET, the results of systematic reviews show that it is not superior to other approaches indicated for this condition [15-17]. At the same time, there is no consensus on how to apply the method, which leads to a lack of standardization of the relative protocols [12]. In addition, great diversity is observed in the methodological design, the instruments and methods of evaluating the variables (pain, functionality) [12]. The disagreement on DTF procedures and the awareness that physiotherapists’ performance may be affected by the lack of understanding of Cyriax’s conclusions motivated the development of this thesis: The primary aim is to analyze the application parameters of the Cyriax method, as well as its effect on the symptoms of LET, by documenting how physiotherapists in Greece use the method. Moreover, and in line with the latest findings [18], a psychometric evaluation of LET will be included in this thesis. Kinesiophobia is an outcome measure that should be considered, as it is affected by LET [18-20].

Interhemispheric Inhibition Between Primary Motor Cortices is Not Altered in Individuals With Chronic Lateral Epicondylalgia

Lateral epicondylalgia (LE), commonly referred to as tennis elbow, is a musculoskeletal condition characterized by pain and sensorimotor dysfunction. In some individuals with chronic unilateral LE, sensorimotor symptoms develop on the unaffected side despite no evidence of tissue damage. Altered interhemispheric inhibition (IHI) is one mechanism that could underpin this phenomenon. The aim of this cross-sectional study was to examine IHI between the primary motor cortices (M1) in individuals with chronic LE and healthy controls. In 20 individuals with chronic LE and 20 healthy participants, transcranial magnetic stimulation was used to assess 1) short and long-latency IHI from the affected (corresponding to the injured side) to the unaffected M1 and 2) corticomotor excitability of the affected and unaffected M1. Sensorimotor function was evaluated bilaterally at the extensor carpi radialis brevis muscle using pressure pain threshold, grip strength, 2-point discrimination, and temporal summation tests. Short- and long-latency IHI from the affected to the unaffected M1 and corticomotor excitability of the affected and unaffected M1 were not altered in individuals with LE compared with healthy participants. No differences in sensorimotor function were observed for the affected or unaffected extensor carpi radialis brevis muscles when individuals with LE were compared with healthy participants. IHI is not altered in individuals with chronic LE. Further studies are required to determine the mechanisms that underpin the development of bilateral sensorimotor symptoms in unilateral LE. PerspectiveIHI is unaltered from the affected M1 (corresponding to the painful muscle) to unaffected M1 in individuals with LE compared to healthy controls. The absence of bilateral sensorimotor dysfunction and low pain severity in this cohort of individuals with LE may explain this finding.

Deficits in neuromuscular control of increasing force in patients with chronic lateral epicondylitis.

Objective: This study investigated the neuromuscular control of increasing and releasing force in patients with chronic lateral epicondylitis (CLE). Methods: Fifteen patients with CLE (10 males, 5 females, 46.5 ± 6.3years) and fifteen healthy participants (9 males, 6 females, 45.3 ± 2.5years) participated in this study. In addition to power grip and maximal voluntary contraction (MVC) of wrist extension, force fluctuation dynamics and characteristics of inter-spike intervals (ISI) of motor units (MUs) with various recruitment thresholds in the extensor carpi radialis brevis (ECRB) and extensor carpi radialis longus (ECRL) during a designated force-tracking task with a trapezoidal target (0%-75%-0% MVC) were assessed. Results: Besides a smaller MVC of wrist extension, the patients exhibited significantly greater task errors (p = 0.007) and force fluctuations (p = 0.001) during force increment than the healthy counterparts. Nevertheless, no force variables significantly differed between groups during force release (p > 0.05). During force increment, the amplitudes of the motor unit action potential of the ECRB and ECRL muscles of the patients were smaller than those of the heathy counterparts (p < 0.001). The patient group also exhibited a higher percentage of motor units (MU) with lower recruitment threshold (<5% MVC) in the ECRL/ECRB muscles and a lower percentage of MU with higher recruitment threshold (>40% MVC) in the ECRB muscle, compared to the healthy group. During force increment, the patient group exhibited a higher rate of decrease in inter-spike intervals (ISIs) of motor units with lower recruitment thresholds (<10% MVC) in the ECRB and ECRL muscles, compared to the control group (p < 0.005). Conclusion: The patients with CLE exhibited more pronounced impairment in increasing force than in releasing force. This impairment in increasing force is attributed to deficits in tendon structure and degenerative changes in the larger motor units of the wrist extensors. To compensate for the neuromuscular deficits, the rate of progressive increase in discharge rate of the remaining smaller motor units (MUs) is enhanced to generate force. Significance: The deficits in neuromuscular control observed in CLE with degenerative changes cannot be fully explained by the experimental pain model, which predicts pain-related inhibition on low-threshold motor units.

Upper Extremity Electromyography During Bouldering: Research Report

Background: Despite the growing popularity of bouldering, little is known about the degree and variabilityof muscle activation that occurs while solving bouldering problems. The purpose of this study was to explorethe electromyography of eight upper extremity and trunk muscles during a session of indoor bouldering whilecompleting four different problems.Methods: Eleven climbers with self-reported ability to climb a V-scale V4 problem grade or higher and regularlyboulder at least two days/week for at least six months participated in this study. Electromyography was used torecord muscle activity of the flexor digitorum superficialis, extensor carpi radialis longus, biceps brachii, tricepsbrachii, anterior deltoid, middle deltoid, posterior deltoid, and latissimus dorsi.Conclusion: The highest average EMG across all four climbs occurred in the flexor digitorum superficialis,latissimus dorsi, and extensor carpi radialis brevis. Significant differences in muscle activity were noted betweenthe anterior deltoid and latissimus dorsi, flexor digitorum superficialis and biceps brachii, triceps brachii andflexor digitorum superficialis, posterior deltoid and latissimus dorsi, and triceps brachii and latissimus dorsi.This information may be useful in developing a strength and conditioning program for

Efficacy of extension wrist hand orthosis on pain, grip strength and electromyographic activities in lateral epicondylitis: A randomized single-blind clinical trial

BackgroundLateral epicondylitis (LE) is one of the most common work-related complications characterized by pain, decreased grip strength and dysfunction of upper limb. Although conservative management such as physiotherapy and orthosis is reported as first line of treatment, sufficient evidence to decide their effectiveness is lacking and remains controversial. PurposeThe current study evaluated and compared the efficacy of a custom-made extension wrist hand orthosis adjunct to usual physiotherapy and therapeutics alone for subjects with LE. Study DesignProspective randomized single-blinded clinical trial. Methods62 subjects with LE were selected as samples using convenience method in this experimental study. They were randomly divided into two groups: usual physiotherapy only and its combination with orthosis. Pain and grip strength were measured using Visual Analog Scale and Jamar hydraulic digital hand dynamometer. Muscle activity of extensor carpi radialis brevis during hand gripping was measured using surface electro-myographic by PowerLab electromyography (AD Instruments, Castle Hill, Australia). Data analysis and comparison were performed for baseline and post-intervention (12weeks). ResultsAfter 12weeks of treatment, there were significant differences in mean scores of pain (1.22 ± 0.51, p = 0.001), maximum voluntary grip strength (5.82 ± 7.84, p = 0.04), and extensor carpi radialis brevis muscle activation (0.082 ± 0.094, p = 0.02) between the therapeutics alone group and the therapeutics plus orthosis group. Compared to therapeutics alone, those getting a combination of physiotherapy and orthosis had greater treatment efficacy (p < 0.05). ConclusionsBoth postintervention (12-week) treatments could affect pain scores, grip strength, and extensor muscle activation. Custom-made extension wrist hand orthosis adjunct to usual physiotherapy is more effective than therapeutics alone in subjects with LE. Therefore, the use of wrist orthosis adjunct to physiotherapy should be recommended in rehabilitation settings for LE.

Median to Radial Nerve Transfer: An 8-Year Experience From a Lower-Middle Income Country

IntroductionWith an incidence of 2-16%, radial nerve palsy is one of the common forms of nerve injuries globally. Radial nerve palsy causes debilitating effects including loss of elbow extension, wrist drop and loss of finger extension. Reparative surgical pathways range from primary repair and neurolysis, to nerve grafting, nerve transfers, and tendon transfers. Due to ease of performance and acceptability and reproducibility of outcomes, tendon transfers are considered the gold standard of radial nerve palsy repair. However, independent finger function cannot be achieved and as such may not give truly desirable results. In lower-middle income countries, the question of nerve transfer versus tendon transfer for patients who are keen to get back to work is key. While tendon transfer recovery is faster, the functional loss is often considered devastating for fine hand function due to loss of grip secondary to lack of wrist and finger extension. In this study, we present our experience of performing median nerve transfers for radial nerve palsy in Pakistan. MethodsWe performed a retrospective case-series of patients undergoing median to radial nerve transfer for radial nerve palsy over a period of 6 y, from 2012 to 2019. Patients with radial nerve palsy were diagnosed via electromyography and nerve conduction studies. The procedure involved coapting the branches of the flexor carpi radialis and flexor digitorum superficialis (long and ring finger) nerves to the posterior interosseous nerve and extensor carpi radialis brevis, respectively. Patients were assessed using the Medical Research Council scale for muscle strength of wrist, finger and thumb extension separately at 1 y time. Our results were then compared to results from similar nerve transfer studies. ResultsWe operated on 10 right-hand dominant patients, eight males and two females with a median age of 33 y (6-63 y). four sustained injury to the right hand and six to the left. Causes of the injuries included road traffic accident (n = 3), firearm injury (n = 4), shrapnel (n = 1), iatrogenic injury (injection in deltoid region (n = 1) and fall (n = 1). Types of fracture included mid humerus fracture, fracture of the surgical neck of the humerus, and supracondylar fracture of the humerus. Median time to surgery since injury was 4 mo (1-8 mo). Independent wrist extension was M4+ in all patients and independent finger extension was M4+ in seven and M4-in two patients. However, a patient who presented late at 8 mo had poorer finger outcomes with extension at M2-. All patients had independent movement of fingers. ConclusionsNerve transfer is a reliable method of post traumatic nerve repair and reinnervation, particularly in lower-middle income countries, even in cases where the nerve damage is severe and extensive and up to 6 mo may have elapsed between injury and presentation. Timely median to radial nerve transfer is a highly recommended option for radial nerve palsy, with regular follow-ups and physical therapy added to ensure positive outcomes.

Proximal forearm nerve branching patterns: an anatomical study and its clinical significance.

The aim of this study was to add to the understanding of nerve branching patterns in the proximal forearm and consider optimal nerve transfer options to address the various injuries that affect the function of the upper extremity. Eleven upper-extremity cadaveric specimens were dissected to expose the radial, median, and ulnar nerves in the proximal forearm. The site of origin of nerve branches from the major nerves was assessed, with measurements made in reference to the lateral epicondyle for the radial nerve branches and the medial epicondyle for the median and ulnar nerve branches. The distances to where these branches entered their respective muscles (muscle entry point) were assessed using the same landmarks. To plan a transfer, the length of the nerve branches was then calculated as the difference from the apparent origin from the main nerve trunk to the location where the nerve entered the muscle. Importantly, the nerve branch origin was established as the location of obvious separation from the main nerve trunk without additional fascicular dissection from the major nerve trunk. The number of branches was determined, and the diameter for each branch was measured using a Vernier caliper. The radial nerve branch to the extensor carpi radialis brevis (ECRB) muscle had an average length of 50.7 mm and average diameter of 1.6 mm. The mean medial and lateral lengths of the radial branches to the supinator muscle were found to be 22.2 mm (diameter 1.4 mm) and 15.3 mm (diameter 1.3 mm), respectively. The anterior interosseous nerve (AIN) branch of the median nerve was found 67.8 mm distal to the medial epicondyle with a diameter of 2.3 mm. The flexor carpi ulnaris (FCU) muscle innervation from the ulnar nerve was provided by 3 or 4 branches in most specimens. The second and third of these branches were the longest, with means of 30.5 mm (diameter 1.4 mm) and 30.7 mm (diameter 1.3 mm), respectively. While there is variability of the nerve branching pattern in the proximal forearm between specimens, the authors provide evidence of commonalities (branching patterns and distances) that can facilitate planning for upper-extremity nerve reconstructions. Importantly, all measurements are provided with reference to easily identified bony landmarks and to their muscle entry points to aid operative decision-making. These data complement the growing practice of nerve transfers in the upper extremity for a variety of pathologies.

Turnover Tendon Lengthening Does Not Alter Biomechanical Strength of Pronator Teres-to-Extensor Carpi Radialis Brevis Tendon Transfer.

The pronator teres (PT) to extensor carpi radialis brevis (ECRB) tendon transfer reestablishes wrist extension. Occasionally, the PT periosteal extension is of suboptimal quality to support a strong transfer. In these instances, turnover lengthening techniques can increase usable tendon length. This study characterized the optimal length of tendon turnover and the effect of lengthening on transfer strength. Twenty-seven cadaveric extensor tendons were lengthened using the turnover lengthening technique with 1 to 3 cm of tendon overlap. PT-to-ECRB tendon transfers were performed with native or lengthened ECRB tendons. Tensile testing was used to evaluate stress relaxation and load to failure. The median maximum load to failure increased with increasing overlap length, measuring 35.6 N (quartile 1, 30.2 N; quartile 3, 38.6 N) for 1 cm, 66.0 N (quartile 1, 59.1 N; quartile 3, 74.7 N) for 2 cm, and 96.6 N (quartile 1, 85.9; quartile 3, 114.9 N) for 3 cm of overlap ( P < 0.05). Failure occurred most frequently at the junction of the central overlap and native tendon. Tendons lengthened with 2 and 3 cm of overlap displayed greater stiffness than those with 1 cm ( P < 0.05). Lengthening the ECRB tendon with 2 or 3 cm of overlap did not disrupt the strength or stiffness of subsequent PT-to-ECRB tendon transfers. Turnover tendon lengthening does not detrimentally affect PT-to-ECRB tendon transfer. Greater overlap lengthening distance confers greater stiffness and resistance to rupture. When the periosteal extension of the PT tendon avulses or is of poor quality, the ECRB tendon can be lengthened using the turnover tendon lengthening technique to facilitate a robust transfer.

Arthroscopic debridement of the extensor carpi radialis brevis

Surgical treatment of lateral epicondylitis is reserved for patients who, despite extensive conservative therapy, do not experience satisfactory relief of symptoms. As an alternative to the open procedure, arthroscopic debridement of the extensor carpi radialis brevis (ECRB) muscle is asimple and standardized procedure. The arthroscopic approach also enables the additional treatment of intra-articular pathologies such as loose bodies or osteochondral lesions. After diagnostic arthroscopy, the attachment of the ECRB is visualized via the anteromedial portal, so that under visual control the debridement of the tendon fibers of the ECRB and its bony insertion site can be performed via the anterolateral portal. Postoperatively, there is no restriction of movement of the elbow joint. The outcome after arthroscopic ECRB debridement described in the literature is equivalent to that of other surgical techniques.

Clinical Outcomes of Upper Extremity Nerve Transfers in Neuralgic Amyotrophy.

Neuralgic amyotrophy (NA) is a disease affecting peripheral nerves. Treatment has historically been conservative, as the natural course of the disease was thought to be self-limiting. Recent work has demonstrated that as many as two-thirds of people with NA have persistent pain, fatigue, or weakness. At the authors' center, supercharged end-to-side (SETS) nerve transfers are commonly performed in patients with NA to optimize motor recovery while allowing for native axonal regrowth. The authors describe the technique and clinical outcomes of patients with NA affecting the anterior interosseous nerve (AIN) who were treated with SETS nerve transfer from extensor carpi radialis brevis to AIN. Ten patients (90% male; mean age, 51.3 ± 9.7 years) underwent extensor carpi radialis brevis-to-AIN transfer at a mean period of 6.4 ± 1.4 months after onset of symptoms. Mean postoperative follow-up duration was 14.8 ± 3.2 months. Before surgery, all patients demonstrated clinically significant weakness in the flexor pollicis longus (FPL), flexor digitorum profundus muscle to the index finger (FDP2), or both. FPL strength improved from a median Medical Research Council (MRC) grade of 1.5 to 4 ( P = 0.011) and FDP2 strength improved from a median MRC grade of 1 to 5 ( P = 0.016). A postoperative MRC grade of 4 or greater was achieved in nine of 10 (90%) FPL and 10 of 10 (100%) FDP muscles. This is the first report of SETS nerve transfer for the treatment of NA. The outcomes of this work suggest that SETS nerve transfers may be an option to optimize motor outcomes in patients with NA. Therapeutic, IV.

Volar versus dorsal approach for supinator to posterior interosseous nerve transfer: An anatomical study in cadavers.

Supinator to posterior interosseous nerve (SPIN) transfer allows reconstruction of finger/thumb extension and thumb abduction for low radial nerve palsy, incomplete C6 tetraplegia, and brachial plexus injury affecting C7-T1. No study has compared dorsal versus volar approach to perform SPIN transfer. This comparison is studied in the present work, assessing supinator motor branch length and ability to achieve nerve transfer from either approach. Ten fresh frozen cadavers were randomly allocated to receive either a dorsal or volar approach to PIN and supinator radial and ulnar branches (RB=radial, UB=ulnar). Supinator head innervation patterns were documented. RB and UB lengths, forearm lengths measured from ulnar styloid to olecranon, visualization of extensor carpi radialis brevis (ECRB) motor nerve without additional dissection, and ability to perform tension-free nerve transfer were assessed. Nine of 10 specimens had supinator branches innervating both heads. The ECRB nerve was visualized in all volar but only one dorsal approach. No significant differences in forearm length were found. Volar with elbow extended: mean RB length was 35±7.8 mm and UB was 37.8±9.3 mm. Dorsal with elbow extended: mean RB length was 30±4.1 mm and UB was 38.8±7.3 mm. Dorsal with elbow flexed 90°: RB was 25.6±3.8 mm and UB was 34.8±4.8 mm. No significant differences were found in branch lengths between approaches (dorsal vs. volar UB, p=.339; dorsal vs. volar RB, p=.117). All limbs achieved tension-free coaptation. Neither approach demonstrated superiority in achieving tension-free nerve transfer. Volar permitted immediate identification of ECRB nerve whereas this was only visualized in one dorsal specimen without additional dissection. Overall, the volar approach allows direct coaptation in elbow extension, mimicking maximal physiologic tension for neurorrhaphy. It simultaneously permits additional procedures for pinch reconstruction via single exposure, circumventing limb/microscope maneuvering, dorsal dissection, and increased operative time. Ultimate choice of approach should depend on surgeon familiarity and potential need for additional simultaneous transfers.