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Case Reports |
RA Ekstrom, PT, DSc, OCS, is Assistant Professor, Department of Physical Therapy, University of South Dakota, 414 E Clark St, Vermillion, SD 57069 (USA) (rekstrom{at}usd.edu).
K Holden, PT, MSPT, is Physical Therapist, Department of Physical Therapy, Sioux Valley Vermillion Hospital, Vermillion, SD
Address all correspondence to Dr Ekstrom
Submitted September 7, 2001;
Accepted May 12, 2002
 | Abstract |
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Key Words: Lateral elbow pain • Nerve entrapment • Neural tension testing • Radial tunnel syndrome
| Introduction |
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 TopAbstract Introduction Case DescriptionIntervention and OutcomesDiscussionReferences |
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Another cause of lateral elbow pain is radial tunnel syndrome (RTS) associated with entrapment of the deep radial nerve.9,10 The radial tunnel begins where the radial nerve runs in a furrow between the brachioradialis and brachialis muscles in the distal part of the arm.11,12 About 1.3 cm proximal to the radiohumeral joint, the radial nerve divides into a superficial branch and a deep branch (Fig. 1). The deep radial nerve continues into the radial tunnel and in most cases passes through a fascial extension from the origin of the ECRB muscle, innervates it, and gives off a small recurrent branch that travels laterally to the lateral epicondyle.11,13 The nerve then courses under the arcade of Frohse, which is a semicircular arch at the proximal edge of the supinator muscle about 2.3 cm distal to the radiohumeral joint.11 The nerve passes through the substance of the supinator muscle, innervates it, and exits the supinator muscle about 6.4 cm distal to the radiohumeral joint, where the radial tunnel terminates.9 As the deep radial nerve exits the supinator muscle, it is called the posterior interosseous nerve (PIN).12,14 The PIN divides into terminal branches that innervate the extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, extensor polli-cis longus and brevis, extensor indicis, and the abductor pollicis longus muscles.14
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Symptoms of RTS may masquerade as lateral epicondylitis. The examination for RTS should include a thorough history. The symptoms may include deep, aching, diffusely localized pain around the lateral side of the elbow and dorsal side of the forearm that sometimes radiates to the hand.10,13,16,18 The pain is initiated and intensified by repetitive movements incorporating forearm pronation.10 It has been postulated that repetitive pronation or supination movements may cause fibrosis of the arcade of Frohse, leading to a greater chance of entrapment.13
We believe that the examination also should include palpation for abnormal tenderness over the radial tunnel (Fig. 2). The forearm is placed in neutral pronation/supination and palpated in a line anterior to the radiohumeral joint to the midpoint between the radius and ulna on the posterior aspect of the forearm over a relaxed ECRB muscle. The tunnel is about as long as the width of 4 palpating fingertips (5–6 cm), as pictured in Figure 2.10 Greater tenderness should be expected over the radial tunnel than at the lateral epicondyle, indicating an RTS.10,13 Compression of the deep radial nerve is another part of the examination. The deep radial nerve can be compressed by stretching the supinator muscle by pronating the forearm to end-range with the elbow extended.17 Pronation also is believed to tighten the fascial origin of the ECRB muscle over the nerve.9 Resistance to supination with the supinator and ECRB muscles in the stretched position will cause further compression of the nerve.10
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Research has demonstrated that nerves normally move in relation to their surrounding connective tissues.25,26 Entrapment of a nerve could restrict its movement, placing tension on the nerve during some motions of the upper extremity. The abnormal tension produced in the nerve has been called "adverse mechanical tension."22–24 In addition, entrapment may cause ischemia, inflammation, and pain, or even axonal degeneration in the nerve.24 Injured or inflamed peripheral nerves usually have increased sensitivity to mechanical loading.27,28 Nerve tension testing, which places mechanical tension on a nerve, would be expected to increase pain from the nerve.
Butler24 described nerve tension testing positions and mobilization techniques for the nerves of the upper extremity. Butler and others believe that the mobility of a nerve that has restricted longitudinal movement often can be restored using what they call "neural mobilization techniques,"23,24 which are techniques designed to free nerves for movement. We could find no research evidence that a nerve can be mobilized once its motion is restricted. The purpose of this case report is to describe the examination of and the intervention for a patient with chronic lateral elbow pain who had signs of nerve entrapment.
| Case Description |
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TopAbstractIntroductionCase DescriptionIntervention and OutcomesDiscussionReferences |
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Examination
The patient started experiencing right lateral elbow pain about 4 months before being referred for physical therapy. She could not identify an injury, but attributed her problem to the many hours of computer keyboard work each day at her job. Her elbow pain varied from day to day, depending on her activities and use of the right upper extremity. In addition to using a keyboard, she found that other gripping or repetitive activities, such as using a scissors or stirring while baking, aggravated her symptoms (caused increased lateral elbow pain).
Using a visual analog scale (VAS), where 0 was "no pain" and 10 was "the most severe pain imaginable," her pain level varied from 1.0 to 6.0, depending on her activity level. The VAS has been shown to have test-retest reliability of .97 using a Pearson product moment correlation when comparing individuals or groups of patients examined.29 We did not assess the reliability of our own measurements.
The pain initially started as an ache in her elbow and gradually increased in intensity over time. The patient pointed to an area corresponding to the radial tunnel as the location of her pain. She said that she occasionally felt a burning type of pain over the lateral epicondyle area of the right elbow.
The cervical spine was examined first with the patient in a sitting position. Cervical range of motion (ROM) was within normal limits for her age.30 Cervical compression and distraction tests were negative. Cervical compression was applied by placing downward pressure over the crown of the head for 5 seconds with the neck rotated, side bent, and extended to each side. Distraction of the neck was applied by placing one hand under the occiput and one hand under the chin and then lifting upward for 5 seconds. None of the movements of the cervical spine reproduced the elbow pain.
The passive ROM of her left and right shoulders, elbows, wrists, and fingers was examined. Her ROM was within normal limits,31 and she did not have pain in any of the joints during passive movements. Compression and distraction of the radiohumeral joint also did not cause pain. Passive stretching of the extensor forearm musculature with the wrist and fingers flexed and elbow extended caused moderate, tolerable pain, but no limitation of the ROM.
Isometric contraction of the wrist extensor muscles and resistance to middle finger extension with the elbow extended caused pain in the area of the radial tunnel, as did resisted forearm supination. Manual muscle testing of the right wrist, finger, and thumb extensors revealed force that was rated as 4/5. The force of the same muscle groups on the left side was rated as 5/5. Grip force (averaged for 3 contractions), as measured with a hand dynamometer (Jamar*) with the fingers flexed to mid-range and with the elbow flexed to 90 degrees, was 28 kg on the left with no pain and 14 kg on the right, which produced increased but tolerable pain in the lateral aspect of her elbow and proximal forearm. Peolsson et al32 evaluated intrarater and interrater reliability when determining grip force with a hand dynamometer and obtained intraclass correlation coefficients ranging from .85 to .98.
The patient had more pain when the radial tunnel was palpated than when the right lateral epicondyle was palpated. There was mild discomfort with palpation of the lateral epicondyle, but acute pain with palpation of the radial tunnel. She also had some tenderness when the muscle bellies of the extensor carpi radialis longus and extensor carpi radialis brevis muscles were palpated.
Neural tension testing was performed on both upper extremities for comparison, using tests similar to those proposed for the median and radial nerves.24 In the past, the validity of neural tension testing has been based on observation of how the nerves may be stretched with movements and their anatomical positions in relation to joints, rather than on data on the mechanical forces actually produced in the nerves during different movements or on data based on patient outcomes.23 Recently, Kleinrensink et al33 used buckle force transducers to assess the tensile forces in the nerves of cadavers during nerve tension testing. They concluded that the median nerve tension test was both sensitive and specific because it produced a large amount of tension in the median nerve with minimal tension produced in either the ulnar nerve or the radial nerve. Based on the sensitivity and specificity of the median nerve test, Kleinrensink and colleagues concluded that the test is a valid test for producing tension on the median nerve. They, however, did not find the radial nerve test to be specific or sensitive. Even though the radial nerve test produced the greatest amount of tension in the radial nerve, the tension was about 31% less in the radial nerve than in the median nerve. When adding contralateral rotation and side bending to the cervical spine, the tension in the radial nerve was increased to slightly more than in the median nerve. Because of the procedures used in the study, we do not know if the tension produced would cause pain in a patient.
The median nerve test was performed using 5 different movements in sequence (Fig. 3). The movements were: shoulder girdle depression with the elbow flexed to 90 degrees, shoulder abduction with the elbow flexed to 90 degrees, shoulder lateral (external) rotation, wrist and finger extension with the forearm supinated, and elbow extension. Each movement was taken to a point of perceived uncomfortable tension, according to patient feedback, and then released just to the point where the uncomfortable tension disappeared. At that point, passive joint ROM was recorded.
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The passive ROM measurements for the left and right upper-extremity joints during the nerve tests are shown in Table 1 for the median nerve and in Table 2 for the radial nerve. Based on work by Coppieters et al,36 passive ROM in both extremities was less than what would be considered normal, and the ROM of the right upper extremity was much more limited than that of the left upper extremity. In a "normal" tension test, we could expect a limitation of a few degrees of ROM only in the joint that is moved last in the sequence because it is the last movement that places maximum stretch on the nerve. With the median nerve test, Coppieters et al36 found an average limitation of 11 degrees of elbow extension when the wrist was extended before the elbow. The radial nerve test reproduced the pain in the right lateral elbow area, whereas the median nerve test did not.
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Based on the results of manual muscle testing, the patient had weakness in the wrist, thumb, and finger extensors, and she also had decreased grip force. It was not possible to determine whether this weakness was due to pain or due to the partial denervation of these muscles that can occur with entrapment neuropathies. Even though the results of force testing may not have contributed to diagnosis, we believe it is very important to examine for force deficits.
We concluded that the patient's primary problem was an entrapment of the deep radial nerve. Using the Guide to Physical Therapist Practice,37 the patient's problem could be classified under Preferred Practice Pattern 4E ("Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Localized Inflammation") or 5F ("Impaired Peripheral Nerve Integrity and Muscle Performance Associated With Peripheral Nerve Injury").
| Intervention and Outcomes |
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TopAbstractIntroductionCase DescriptionIntervention and OutcomesDiscussionReferences |
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The patient was treated with ultrasound (3 MHz at 0.5 W/cm2 for 8 minutes) over the radial tunnel for a deep heating effect to improve soft tissue extensibility, followed by "neural mobilization techniques" to reduce the nerve entrapment for the first week of treatment (4 visits). These techniques were performed on both upper extremities. Mobilizations were performed on the left side only as a preventive measure with the notion that reduced mobility of the nerves could cause problems in the left upper extremity in the future. For mobilization with presumably greater emphasis on the median nerve (what sometimes is called "mobilization with a median nerve bias"), the patient's upper extremity was taken through the sequence of movements used during testing. This mobilization involved positioning, very similar to that used for the median nerve test, that would place the greatest amount of tension on the median nerve and produce the greatest movement of the median nerve. The mobilization was then performed by flexing and extending the elbow.
For the mobilization with presumably a greater emphasis on the radial nerve (what is sometimes called "mobilization with a radial nerve bias"), the sequence was slightly changed from the testing procedure so that mobilization could be carried out with elbow flexion and extension. This mobilization involved positioning, very similar to that used for the radial nerve test, that would place the greatest amount of tension on the radial nerve and produce the greatest movement of the radial nerve. The wrist and fingers were flexed prior to elbow extension during the mobilization, whereas during the radial nerve test, the elbow was extended prior to wrist and finger flexion. In the early stages of mobilization of the right side radial nerve, the fingers and wrist were not flexed because elbow extension was limited without finger and wrist flexion. As elbow extension improved, the fingers and wrist were first flexed prior to the mobilization procedure.
The mobilizations were performed gently, extending the elbow for about 2 seconds just into the range where the patient felt tension but no pain and then flexing the elbow to the point where the patient felt no tension. Six to 7 mobilizations were done emphasizing the median nerve, followed by 6 to 7 mobilizations emphasizing the radial nerve. The patient's response dictated the degree of elbow extension during mobilization. The patient did not report pain prior to her perception of tension during mobilization. Only with increasing tension did she report any pain or discomfort. If pain or discomfort or any signs, such as tingling in the hand, were produced, the range of elbow extension was reduced.
The patient was instructed to perform "neural mobilization exercises" one time per day at home in a similar manner to the technique used in the clinic. She was taught how to perform the same sequence of extremity positioning and then was taught how to use active elbow extension as the mobilization movement. The patient was seen 2 days after the first visit to again treat her and review her home program to ensure she was progressing well and not aggravating her condition with too aggressive mobilizations. She was treated 2 more times over the next 4 days to help facilitate the neural mobilization process and ensure the home program was going well.
After the first week of physical therapy intervention, the ROM in the right upper extremity during nerve testing increased (Tabs. 1 and 2). The patient's pain ratings on the VAS, however, remained the same (Tab. 3). Her grip force increased to 20 kg on the right. During palpation, the patient indicated she had a small decrease in tenderness or pain over both the right lateral epicondyle and radial tunnel. She initially had mild discomfort with palpation of the right lateral epicondyle and acute pain with palpation of the right radial tunnel. At that time, the patient started a strengthening and stretching program in addition to neural mobilization exercises. The strengthening program consisted of resistive exercises for the right wrist extensors with the elbow flexed to 90 degrees. The patient started with a 0.9-kg (2-lb) weight and did 3 sets of 10 repetitions, with a 30-second stretch of the wrist extensors after each set.38
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As Tables 1 and 2 indicate, the patient's passive ROM continued to increase during testing that was designed to stretch the nerves thought to be limited in movement, in both her left and right upper extremities, during the first 3 weeks of treatment (8 visits). The mobility was nearly the same on the right and left sides. The right grip force improved to 34 kg compared with the initial value of 14 kg. The grip force of the left hand improved from an initial value of 28 kg to 36 kg. The patient then could perform her strengthening program for her right wrist extensors with a 2.25-kg (5-lb) dumbbell. The patient had no pain with self-stretching of the right wrist extensors and minimal discomfort with a strong isometric contraction of the wrist extensors. The patient was pain-free unless she performed a considerable amount of aggravating activities. Aggravating activities could still increase pain levels to 4.0 on the VAS.
The patient continued with 6 more physical therapy visits once a week, for a total of 14 visits over a 10-week period. The goal of the last 6 weeks of intervention was to get the patient to a point where all activities were pain-free and to have the patient progress with her home exercise program. At the time of the last visit, the passive ROM of the upper extremities was maintained during testing. The patient was able to perform the exercise program with a 3.15-kg (7-lb) weight and the grip force on the right had improved to 39 kg. She had minimal tenderness or pain with palpation over the lateral epicondyle, the radial tunnel, and muscle bellies of the extensor carpi radialis longus and brevis muscles. She said she was pain free 70% to 80% of the time and only had an aching type of pain when she performed activities that would normally aggravate her elbow. Her employer had provided her with a new ergonomically designed workstation 2 weeks before the termination of physical therapy, which she said helped to reduce stress on her right upper extremity at work.
The patient was contacted 4 months after discharge from physical therapy for follow-up on the status of her right lateral elbow pain. She reported that she had resumed all normal activity and was not having any pain or other problems with her elbow.
| Discussion |
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TopAbstractIntroductionCase DescriptionIntervention and OutcomesDiscussionReferences |
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Many of the patient's signs and symptoms were similar to those of patients with lateral epicondylitis, making it difficult to distinguish between the 2 disorders. We found a reduction in joint passive ROM during neural tension testing that presumably required movement of the nerves. Yaxley and Jull39 evaluated "neural tension" in 20 patients with a diagnosis of tennis elbow and also found a tendency for reduced passive ROM during testing in the upper extremity with the tennis elbow compared with the patients' other upper extremity. The "neural tension test with a bias toward the radial nerve" reproduced the patients' symptoms in 55% of the cases. It may be that some patients, including the patient in this case report, actually have a syndrome affecting both the common extensor tendon of the forearm and the deep radial nerve.
We believe that the "neural tension tests" and "neural mobilization techniques" performed were useful examination and intervention tools for this patient. Some authors have proposed that, if a nerve's gliding movement is restricted in relation to surrounding tissues, "adverse neural tension signs" can be produced in the nerve during neural tension testing.22–24 The 2 most prevalent signs are reduction in joint ROM and reproduction of symptoms.22 The most obvious sign demonstrated by the patient was reduced joint passive ROM. Symptoms were reproduced only with the test designed to stretch the radial nerve. We believe that the radial nerve test could have reproduced the symptoms with either lateral epicondylitis or RTS. The radial nerve test not only places tension on the nerve, but also places tension on the muscles attaching to the lateral epicondyle.
Studies25,26 have demonstrated that peripheral nerves normally glide in relation to surrounding tissues. McLellan and Swash25 inserted a needle electrode into the trunk of the median nerve in the middle portion of the arm in 15 subjects. Active and passive movements of wrist extension and elbow flexion were performed. The movements produced angulation of the needle electrode, indicating that the tip of the electrode moved relative to the site of entry through the skin. The movement of the tip of the needle electrode was always abolished when the electrode was withdrawn from the nerve by 1 mm, indicating that adjacent soft tissues did not share in the movement. McLellan and Swash demonstrated an average of 7.4 mm of excursion of the median nerve in an inferior direction in the arm with extension of the wrist and fingers and 4.3 mm of superior (upward) excursion with elbow flexion. A deep inspiration of the lungs drew the nerve toward the shoulder by as much as 8 mm. Wilgis and Murphy,26 in a study using 15 fresh adult cadavers, showed that the median and ulnar nerves moved longitudinally at the elbow an average of 7.3 mm and 9.8 mm, respectively, with full elbow flexion and extension. The median nerve had 15.5 mm and the ulnar nerve had 14.8 mm of longitudinal gliding at the wrist with full arc wrist flexion and extension.26 The superficial radial nerve moved longitudinally 5.8 mm with movement from full radial deviation to full ulnar deviation.26 The excursion of the nerves was measured just proximal to each joint, relative to an adjacent fixed joint, in which a Kirschner wire was driven into the underlying bone.
The mechanical changes that occur in the peripheral nerves and their surrounding tissues and how the passive ROM of the peripheral joints is reduced when nerve tension tests are applied have been described.33,36,40,41 Our patient had a reduction in the passive ROM in her joints with both the median and radial nerve tension tests. Kleinrensink et al33 demonstrated that nerve tension tests for the upper extremity may not be as discriminatory for each nerve as we might have expected. They found that the test for the median nerve is the most specific, with considerably more tension produced in the median nerve than in either the radial or ulnar nerves. The radial nerve test produced more tension in the median nerve than in the radial nerve, but it did place more tension on the radial nerve than any other test. When adding contralateral rotation and side bending to the cervical spine, the tension in the radial nerve was increased to slightly more than in the median nerve.
Elvey23 and Butler24 proposed that nerves with restricted excursion can sometimes be mobilized. In the opinion of Elvey,23 the mobilization should not go to the end of range and should be of less duration than that used in joint mobilization. We believe that testing procedures and intervention techniques should never be of such strength that symptoms are exacerbated. In this case report, the mobilizations were performed gently and only taken into the range of tension. If pain or discomfort was produced, the passive ROM of the mobilization was reduced so that only tension was felt. The patient's joint ROM increased more quickly than we would expect if soft tissues, such as muscle or joint structures, were being stretched.
It is not known whether outcomes for patients with musculoskeletal problems would be better if decreased joint passive ROM during nerve tension testing were treated with "neural mobilization techniques," which are designed to free nerves for movement. It was interesting that the patient's left grip force improved even though the only intervention for the left upper extremity was mobilization that presumably freed up the nerve. Whether the improvement was the result of the mobilization, of motor learning from repeated testing, or of some other cause could not be determined.
The intervention for the patient in this case report included ultrasound during the first 4 visits, neural mobilization techniques, progressive resistive exercises, and stretching. Others have treated RTS with varying results using ultrasound,19 anti-inflammatory medications,19 corticosteroid injections,42 and splinting.43 If a patient does not respond to conservative treatment, then surgical decompression of the deep radial nerve may be indicated.13,17,19,44
| Footnotes |
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* Sammons Preston, 4 Sammons Ct, Bolingbrook, IL 60440. 
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TopAbstractIntroductionCase DescriptionIntervention and OutcomesDiscussionReferences |
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  J.-L. Croisier, M. Foidart-Dessalle, F. Tinant, J.-M. Crielaard, and B. Forthomme An isokinetic eccentric programme for the management of chronic lateral epicondylar tendinopathy Br. J. Sports Med., April 1, 2007; 41(4): 269 - 275. [Abstract] [Full Text] [PDF]
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