Peripheral Neuropathies of the Median, Radial, and Ulnar Nerves: MR Imaging Features

The median, radial, and ulnar nerves of the upper limbs may be affected by various peripheral neuropathies, each of which may be categorized according to its cause, as either an entrapment or a nonentrapment neuropathy. Entrapment neuropathies, also referred to as nerve compression syndromes, include the supracondylar process syndrome, pronator syndrome, anterior interosseous nerve syndrome, carpal tunnel syndrome, posterior interosseous nerve syndrome, cubital tunnel syndrome, and Guyon canal syndrome. Nonentrapment neuropathies include traumatic nerve injuries, infectious and inflammatory conditions, polyneuropathies, and mass lesions at anatomic locations where entrapment syndromes typically do not occur. Although clinical examination and electrophysiologic testing are the cornerstone of the diagnostic work-up, in certain cases magnetic resonance (MR) imaging may provide key information about the exact anatomic location of a lesion or may help narrow the differential diagnosis. In patients with a diagnosis of peripheral neuropathy, MR imaging may help establish the cause of the condition and provide information crucial for conservative management or surgical planning. In addition, knowledge of the normal anatomy and of the possible causes, typical clinical findings, and MR imaging features of peripheral neuropathies that affect the median, radial, and ulnar nerves allows greater confidence in the diagnosis.

Magnetic resonance imaging of the elbow. Part II: Abnormalities of the ligaments, tendons, and nerves

Part II of this comprehensive review on magnetic resonance imaging of the elbow discusses the role of magnetic resonance imaging in evaluating patients with abnormalities of the ligaments, tendons, and nerves of the elbow. Magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the soft tissue structures of the elbow. Magnetic resonance imaging can detect tears of the ulnar collateral ligament and lateral collateral ligament of the elbow with high sensitivity and specificity. Magnetic resonance imaging can determine the extent of tendon pathology in patients with medial epicondylitis and lateral epicondylitis. Magnetic resonance imaging can detect tears of the biceps tendon and triceps tendon and can distinguishing between partial and complete tendon rupture. Magnetic resonance imaging is also helpful in evaluating patients with nerve disorders at the elbow.

Clinical outcomes following median to radial nerve transfers

PURPOSE

To evaluate the clinical outcomes in patients with radial nerve palsy who underwent nerve transfers using redundant fascicles of median nerve (innervating the flexor digitorum superficialis and flexor carpi radialis muscles) to the posterior interosseous nerve and the nerve to the extensor carpi radialis brevis.

METHODS

This was a retrospective review of the clinical records of 19 patients with radial nerve injuries who underwent nerve transfer procedures using the median nerve as a donor nerve. All patients were evaluated using the Medical Research Council (MRC) grading system. The mean age of patients was 41 years (range, 17-78 y). All patients received at least 12 months of follow-up (range, 20.3 ± 5.8 mo). Surgery was performed at a mean of 5.7 ± 1.9 months postinjury.

RESULTS

Postoperative functional evaluation was graded according to the following scale: grades MRC 0/5 to MRC 2/5 were considered poor outcomes, whereas an MRC grade of 3/5 was a fair result, 4/5 was a good result, and 4+/5 was an excellent outcome. Postoperatively, all patients except one had good to excellent recovery of wrist extension. A total of 12 patients recovered good to excellent finger and thumb extension, 2 had fair recovery, and 5 had poor recovery.

CONCLUSIONS

The radial nerve is commonly injured, causing severe morbidity in affected patients. The median nerve provides a reliable source of donor nerve fascicles for radial nerve reinnervation. The important nuances of both surgical technique and motor reeducation critical for the success of this transfer have been identified and are discussed.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

MR Imaging Features of Radial Tunnel Syndrome: Initial Experience

PURPOSE

To retrospectively assess magnetic resonance (MR) imaging features of radial tunnel syndrome.

MATERIALS AND METHODS

Institutional review board approval was obtained, and informed consent was waived for the retrospective HIPAA-compliant study. MR images of 10 asymptomatic volunteers (six men, four women; mean age, 30 years) and 25 patients (11 men, 14 women; mean age, 49 years) clinically suspected of having radial tunnel syndrome were reviewed for morphologic and signal intensity alterations of the posterior interosseous nerve and adjacent soft-tissue structures. MR images of the asymptomatic volunteers were reviewed to establish the normal appearance of the radial tunnel. MR images of the symptomatic patients were evaluated for the following: signal intensity alteration and morphologic alteration of the posterior interosseous nerve; the presence of mass effect on the posterior interosseous nerve such as the presence of bursae, a thickened leading edge of the extensor carpi radialis brevis, or prominent radial recurrent vessels; signal intensity alteration within the depicted forearm musculature such as edema or atrophy; and signal intensity changes at the origin of the common extensor and common flexor tendons, which would suggest a diagnosis of epicondylitis.

RESULTS

All images of volunteers demonstrated normal morphology and signal intensity within the posterior interosseous nerve and adjacent soft tissues. Two volunteers had borderline thickening of the leading edge of the extensor carpi radialis brevis. Thirteen patients (52%) had denervation edema or atrophy within muscles (supinator and extensors) innervated by the posterior interosseous nerve. One patient had isolated pronator teres edema. Seven (28%) patients had the following mass effects along the posterior interosseous nerve: thickened leading edge of the extensor carpi radialis brevis (n = 4), prominent radial recurrent vessels (n = 1), schwannoma (n = 1), or bicipitoradial bursa (n = 1). The rest of the patients had either normal MR imaging findings (n = 4) or lateral epicondylitis (n = 2).

CONCLUSION

Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome.

Approach to radial nerve palsy caused by humerus shaft fracture: is primary exploration necessary?

INTRODUCTION

While recommendations for early exploration and nerve repair in cases of open fractures of the humeral shaft associated with radial nerve palsy are clear, the therapeutic algorithm for the management of closed humeral shaft fractures complicated by radial nerve palsy is still uncertain. The purpose of this study was to determine whether patients with complete sensory and motor radial nerve palsy following a closed fracture of the humeral shaft should be surgically explored.

PATIENTS AND METHODS

Twenty-five patients with closed humeral shaft fractures complicated by complete radial nerve palsy were retrospectively reviewed during a 12-year period. Surgical intervention was indicated if functional recovery of the radial nerve was not present after 16 weeks of expectant management.

RESULTS

Surgical exploration was performed in 12 patients (48%) after a mean period of expectant management of 16.8 weeks (range: 16-18 weeks). In 2 of them (10%) total nerve transection was found. In the rest 10 patients underwent surgical exploration the radial nerve was found to be macroscopically intact. All intact nerves were fully recovered after a mean time of 21.6 weeks (range: 20-24 weeks) post-injury. In 13 patients (52%) in whom surgical exploration was not performed the mean time to full nerve recovery was 12 weeks (range: 7-14 weeks) post-injury.

CONCLUSIONS

We proposed immediate exploration of the radial nerve in case of open fractures of the humeral shaft, irreducible fractures or unacceptable reduction, associated vascular injuries, radial nerve palsy after manipulation or intractable neurogenic pain. Due to high rate of spontaneous recovery of the radial nerve after closed humeral shaft fractures we recommend 16-18 weeks of expectant management followed by surgical intervention.

Nerve conduction changes in patients with mitochondrial diseases treated with dichloroacetate

Serial measurements of nerve conduction velocities and amplitudes were performed in 27 patients with congenital lactic acidemia over 1 year of sodium dichloroacetate (DCA) administration. Patients were treated with oral thiamine (100 mg) and DCA (initial dose of 50 mg/kg) daily. Nerve conduction velocity and response amplitude were measured in the median, radial, tibial, and sural nerves at 0, 3, 6, and 12 months, and plasma DCA pharmacokinetics were measured at 3 and 12 months. Baseline electrophysiologic parameters in this population were generally below normal but as a group were within 2 standard deviations of normal means. Although symptoms of neuropathy were reported by only three patients or their families, nerve conduction declined in 12 patients with normal baseline studies, and worsening of nerve conduction occurred in the two who had abnormalities at baseline. Peripheral neuropathy appears to be a common side effect during chronic DCA treatment, even with coadministration of oral thiamine. Nerve conduction should be monitored during DCA treatment.

MR imaging of entrapment neuropathies at the elbow

MR imaging has a valuable role in the evaluation of compressive neuropathies at the elbow. Specific MR signs in association with clinical findings can supply an accurate diagnosis. A review of normal anatomy, clinical features, and MR assessment of nerve entrapment syndromes at the elbow is presented.

Radial nerve compression by a large cephalic vein aneurysm: case report

A 43-year-old man had weakness of the extensor muscles in the right forearm and could not extend the right wrist. The apparent disorder was caused by radial nerve compression by a large aneurysm in the cephalic vein in the antecubital fossa. Surgical resection of the aneurysm resolved the symptoms. This exceedingly rare complication of venous aneurysm is discussed. Venous aneurysm should be included in the differential diagnosis of a subcutaneous mass, and diagnosis is best made with Duplex ultrasound scanning. Surgical excision is the appropriate treatment.

Magnetic resonance imaging of innervational and extraocular muscle abnormalities in Duane-radial ray syndrome

PURPOSE

The authors used magnetic resonance imaging (MRI) to study extraocular muscles (EOMs) and nerves in Duane-radial ray (Okihiro) syndrome (DRRS) caused by mutations in the transcription factor SALL4.

METHODS

The authors examined four male and two female affected members of a pedigree previously reported to cosegregate DRRS and a heterozygous SALL4 mutation. Coronal T1-weighted magnetic resonance images of the orbits and heavily T2-weighted images in the plane of the cranial nerves were obtained in four subjects. MRI findings were correlated with motility examinations and published norms obtained using identical technique.

RESULTS

Five of the six subjects with DRRS had radial ray abnormalities including thumb, radial artery, radial bone, and pectoral muscle hypoplasia. Three had bilateral and three had unilateral ocular involvement. Seven eyes had limitation of both abduction and adduction, whereas two had limitations only of abduction. Most affected eyes had lid fissure narrowing and retraction in adduction. Intraorbital and intracranial abducens nerves (CN6) were small to absent, particularly ipsilateral to abduction deficiency. All subjects undergoing MRI had normal intracranial oculomotor nerves (CN3). Optic nerve (ON) cross-section findings were similar to normal. EOMs and pulleys were structurally normal in most subjects. In some affected orbits, a branch of CN3 closely approximated and presumably innervated the LR.

CONCLUSIONS

DRRS encompasses a Duane syndrome phenotype, with a variable and asymmetric endophenotype including marked CN6 hypoplasia and probable innervation or coinnervation of the LR by CN3. This endophenotype is more limited than reported in DURS2-linked Duane syndrome (On-line Mendelian Inheritance in Man, OMIM 604356) and CFEOM1 (OMIM 135700), which are clinically similar congenital cranial dysinnervation disorders that also feature CN3 hypoplasia and more widespread EOM abnormalities.

Radial nerve palsy associated with humeral shaft fracture. Is the energy of trauma a prognostic factor?

BACKGROUND

Radial nerve palsy associated with humeral shaft fractures is the most common nerve lesion complicating fractures of long bones. The purpose of the study was to review the outcome of surgical management in patients with low energy and high energy radial nerve palsy after humeral shaft fractures.

METHODS

Eighteen patients were treated operatively for a humeral shaft fracture with radial nerve palsy. The mean age was 32.2 years and the mean follow up time was 66.1 months (range: 30-104). The surgical management included fracture fixation with early nerve exploration and repair if needed. The patients were divided in two groups based on the energy of trauma (low vs. high trauma energy). The prevalence of injured and unrecovered nerves and time to nerve recovery were analysed.

RESULTS

Five patients sustained low and 13 high energy trauma. All patients with low energy trauma had an intact (4) or entrapped (1) radial nerve and recovered completely. Full nerve recovery was also achieved in five of 13 patients with high energy trauma where the nerve was found intact or entrapped. Signs of initial recovery were present in a mean of 3.2 weeks (range: 1-8) for the low energy group and 12 weeks (range: 3-23) for the high energy group (p=0.036). In these patients, the average time to full recovery was 14 and 26 weeks for the low and high energy trauma group respectively. Eight patients with high energy trauma had severely damaged nerves and failed to recover, although microsurgical nerve reconstruction was performed in 4 cases. Patients with high energy trauma had a prolonged fracture healing time (18.7 weeks on average) compared to those with low energy fractures (10.4 weeks), (p=0.003).

CONCLUSIONS

The outcome of the radial nerve palsy following humeral fractures is associated to the initial trauma. Palsies that are part of a low energy fracture uniformly recover and therefore primary surgical exploration seems unnecessary. In high energy fractures, neurotmesis or severe contusion must be expected. In this case nerve recovery is unfavourable and the patients should be informed of the poor prognosis and the need of tendon transfers.

Prognostic values of electrodiagnostic studies in traumatic radial neuropathy

It is important to have strong predictors of outcome in traumatic neuropathies so that appropriate management can be instituted early. Our objective in this study was to evaluate the prognostic value of electrodiagnostic studies in traumatic radial neuropathy. In this retrospective study, 33 of 67 subjects with traumatic radial neuropathy met the inclusion criteria. Good outcome was defined as grade 3 or higher strength on the Medical Research Council scale in wrist extensors. Compound muscle action potential (CMAP) responses from extensor indicis proprius (EIP) predicted prognosis: 92% of subjects with a recordable CMAP had a good outcome; and 65% of those with an absent response had a good outcome. Recruitment in brachioradialis was also predictive: 92% of those with full, central, or reduced recruitment had a good outcome; 67% of those with discrete recruitment had a good outcome; and only 33% of those with absent recruitment had a good outcome. Studies performed more than 3 months after injury produced more prognostic certainty than those performed earlier. We conclude that electrodiagnostic studies produce useful prognostic information in traumatic radial neuropathy. It is noteworthy, however, that 65% of subjects with an absent radial CMAP (suggesting complete or nearly complete axon loss) still have a good outcome.

Radial tunnel syndrome: a surgeon's perspective

Radial tunnel syndrome is relatively uncommon but is an important cause of lateral forearm pain. Clinical examination is a crucial part of the diagnosis with weakness of finger extension and local tenderness at the ligament of Frohse being the two most important. Surgical release of the superficial head of the supinator muscle and the division of the ligament of Frohse is usually successful in relieving the symptoms. Radial tunnel syndrome (supinator syndrome) can coexist with tennis elbow and cervical brachial neuritis. The diagnosis must be considered when there is atypical tennis elbow or de Quervain's tenovaginitis stenosans resistant to normal treatment. The relationship between radial tunnel syndrome and work remains unclear but repeated supination of the forearm combined with extension of the elbow appears to aggravate the symptoms. There is no scientific evidence to suggest a direct causal relationship between work practices and radial tunnel syndrome.

Brachioradial pruritus—A peculiar neuropathic disorder

The case is presented of a middle-aged woman who suffered from lancinating itch on the dorsolateral aspect of the upper arm after a loco-regional injury, first on the right and later on the left side. Brachioradial pruritus (BRP) was diagnosed. Neurophysiologic examination was compatible with a neuropathy at the C5-C6 level, while a negative nerve root block supported an additional central impact. The presumed pathophysiology of BRP is discussed in terms of a neuropathic disorder. We suggest that damage from whatever cause from either the cutaneous nerves or from the more proximal sensory pathways may be the causative physiopathologic basis for this enigmatic disorder. BRP was refractory to different therapeutic approaches, except to lamotrigine. As BRP presents a therapeutic challenge, it seems important to report lamotrigine as a potential new therapy.

Radial nerve palsy after arthroscopic anterior capsular release for degenerative elbow contracture

Because the use of arthroscopy has increased recently for the treatment of elbow lesions, reports of complications have become more common. Nerve injury after arthroscopic anterior capsular release is an extremely rare complication, with 4 reported cases worldwide. We usually use a sharp-tipped electrocautery device with a 0.5-mm diameter during arthroscopic capsular release. In this case, because the former was not prepared, we used a ball-tipped electrocautery device with a 3-mm diameter. Herein, we experienced a case of radial nerve palsy after arthroscopic anterior capsular release using a ball-tipped electrocautery device on a degenerative elbow contracture. We supposed that the electrocautery device caused transiently thermal injury of the radial nerve despite proper portal entry site, intra-articular distension, and gentle arthroscopic manipulation. Elbow arthroscopy remains a technically difficult procedure with the potential for neurologic complications. To perform surgery safely, knowledge of the regional neuroanatomy and a thorough understanding of proper instrument usage are required.

Mononeuropathies of the radial nerve: clinical and neurographic findings in 91 consecutive cases

Retrospective features of 91 consecutive cases (68 men, 23 women; mean age 44.4 years) of radial mononeuropathy diagnosed over the last 8 years in two electromyography (EMG) services are reported to define the clinical and electrophysiological findings of radial neuropathies in relation to traumatic and non-traumatic causes and site of injury. The occurrence of radial neuropathy was 0.65 x 100 first electromyographic examinations. The most frequent site of damage was the main trunk at the spiral groove of the humerus (36%); the most frequent cause was nerve trauma (70%) due to fracture (36%). In neuropathies of the main trunk and posterior interosseous (PI) nerve, "complete nerve injury" was observed in 36% of cases, conduction motor block in 33% and motor conduction velocity slowing in 46%. At least one of these findings was present in 51%, whereas motor neurography was normal in 13% of cases. Sensory action potential (SAP) anomalies were observed in 51% of cases. In neuropathy of the superficial radial nerve, no SAP was detected in 30% of cases; in all others except one, SAP was reduced in amplitude. Non-traumatic neuropathies showed severer conduction block and less severe anomalies of SAP than traumatic neuropathies. No differences were found between men and women. EMG is essential for confirming the site of injury and neurographic study may be helpful for diagnosis, providing information about lesion type and severity.

Proximal Radial Compression Neuropathy

Proximal radial nerve compression occurs infrequently and is diagnosed successfully even less frequently. A large clinical series of patients with proximal radial nerve compression neuropathy was reviewed to determine better the common symptoms, physical findings, and electrodiagnostic findings, and to identify the predictors of better or worse outcome after surgical decompression. Seventy-nine proximal radial compression neuropathies were treated in 71 patients by the same surgeon between 1991 and 2000. The most consistent symptoms were deep aching pain in the forearm, pain radiation to the neck and shoulder, and a "heavy" sensation of the affected arm. The most common physical findings were tenderness over the radial nerve at the supinator muscle level, pain on resisted supination, and the presence of a Tinel sign over the radial forearm. Electrophysiologic studies were of limited value in diagnosis, with 90% of patients having normal findings. On operation, prominent pathology of the posterior interosseous nerve was observed in 36 of 79 limbs (46%). Follow-up ranged from 12 to 86 months (mean, 21 months) with no significant complications or recurrence of symptoms. Of the 79 nerve decompressions, 77% had excellent recovery and 20% were judged to be good. Of 69 patients employed when treated, 60 resumed gainful employment, including 53 who returned to their regular jobs. Proximal radial compression neuropathies are uncommon but present with a basic constellation of symptoms and physical findings, and decompression can provide excellent relief of symptoms.

Current approach to radial nerve paralysis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Identify all potential points of radial nerve compression and other likely causes of radial nerve injury. 2. Accurately diagnose both surgical and nonsurgical causes of radial nerve paralysis. 3. Define a safe and effective approach to the surgical release and reconstruction of the radial nerve. Radial nerve paralysis, which can result from a complex humerus fracture, direct nerve trauma, compressive neuropathies, neuritis, or (rarely) from malignant tumor formation, has been reported throughout the literature, with some controversy regarding its diagnosis and management. The appropriate management of any radial nerve palsy depends primarily on an accurate determination of its cause, severity, duration, and level of involvement. The radial nerve can be injured as proximally as the brachial plexus or as distally as the posterior interosseous or radial sensory nerve. This article reviews the etiology, prognosis, and various treatments available for radial nerve paralysis. It also provides a new classification system and treatment algorithm to assist in the management of patients with radial nerve palsies, and it offers a simple, five-step approach to radial nerve release in the forearm.

Surgical treatment and outcomes in 45 cases of posterior interosseous nerve entrapments and injuries

Object

The authors report data in 45 surgically treated posterior interosseous nerve (PIN) entrapments or injuries.

Methods

Forty-five PIN entrapments or injuries were managed surgically between 1967 and 2004 at Louisiana State University Health Sciences Center (LSUHSC) or Stanford University Medical Center. Patient charts were reviewed retrospectively. The LSUHSC grading system was used to assess PIN-innervated muscle function.

Injuries were caused by nontraumatic (21 PIN entrapments and four tumors) and traumatic (nine lacerations, eight fractures, and three contusions) mechanisms. Presentations included weakness in the extensor carpi ulnaris muscle, causing compromised wrist extension and radial drift; extensor digitorum, indicis, and digiti minimi muscles with paretic finger extension; extensor pollicis brevis and longus muscles with weak thumb extension; and abductor pollicis longus muscle with rare decreased thumb abduction due to substitutions of the median nerve–innervated abductor pollicis brevis muscle and, at 90°, the extensor pollicis brevis and longus muscles. Preoperative evaluations consisted of electromyography and nerve conduction studies, elbow and forearm plain x-ray films, and magnetic resonance imaging for tumor detection.

At surgery, in continuity lesions were found in 21 entrapments and three fracture-related and three contusion injuries; all transmitted nerve action potentials (NAPs) and were treated with neurolysis. Five fracture-related PIN injuries, one of which was a lacerating injury, were in continuity and transmitted no NAPs; graft repairs were performed in all of these cases. Among nine lacerations, three PINs appeared in continuity, although intraoperative NAPs were absent. Two of these nerves were treated with secondary end-to-end suture anastomosis repair and one with secondary graft repair. There were six transected lacerations: three were treated with primary suture anastomosis repair, two with secondary suture anastomosis, and one with graft repair. Four tumors involving the PIN were resected. Most muscles innervated by 45 PINs had LSUHSC Grade 3 or better functional outcomes.

Conclusions

Forty-five PIN entrapments or injuries responded well to PIN release and/or repair.

Injury to the radial nerve caused by fracture of the humeral shaft:Timing and neurobiological aspects related to treatment and diagnosis

The radial nerve may not function in association with fractures of the humeral shaft. There are various opinions about the causes and treatment. We report a case of complete rupture of the radial nerve after a fracture of the proximal shaft of the humerus. The nerve injury was treated with grafting and TENDON transfer. Here we discuss diagnoses and treatments including neurobiological aspects of nervous regeneration. We suggest that electrodiagnostic examination after a radial nerve palsy caused by a humeral fracture is done 5-6 weeks after injury and that nerve repair and reconstruction should be done within two, and not later than three, months after injury.

Surgical treatment and outcomes in 15 patients with anterior interosseous nerve entrapments and injuries

Object

The authors present data obtained in 15 surgically treated patients with anterior interosseous nerve (AIN) entrapments and injuries.

Methods

Fifteen patients with AIN entrapments and injuries underwent surgery between 1967 and 1997 at Louisiana State University Health Sciences Center (LSUHSC) or Stanford University Medical Center. Patient charts were reviewed retrospectively. The LSUHSC grading system was used to evaluate the function of muscles supplied by the AIN.

Nontraumatic injuries included seven AIN compressions by bone or soft tissue. Traumatic injury mechanisms consisted of stretch or contusion (six patients), injection (one patient), and burn scar (one patient). Presentations included weakness in the flexor digitorum profundus (FDP) muscle to the index finger, FDP muscle to the middle finger, pronator quadratus muscle, and flexion of the distal phalanx of the thumb. Preoperative evaluations included electromyography and nerve conduction studies as well as elbow and forearm plain radiographs.

On surgery, lesions in continuity involved seven compressions, four stretch or contusion injuries, and one injection injury, all of which demonstrated nerve action potentials (NAPs) and were treated with neurolysis. Among the seven compression and four stretch or contusion injury cases, six and three patients, respectively, had LSUHSC Grade 3 or better functional recoveries postoperatively. Two stretch or contusion injuries involved lesions in continuity but demonstrated negative NAPs at surgery. Thus, each was treated using a graft repair after resection of a neuroma. There was one burn scar injury, which was treated via an end-to-end suture anastomosis, leading to a functional recovery better than Grade 3.

Conclusions

Fifteen AIN entrapments or injuries responded favorably to nerve release and/or repair.

Radial Nerve Palsy After Humeral Shaft Fractures: The Case for Early Exploration and a New Classification to Guide Treatment and Prognosis

Radial nerve palsies are a common complication associated with humeral shaft fractures. The authors propose classifying these injuries into 4 types based on intraoperative findings: type 1 stretch/neuropraxia, type 2 incarcerated, type 3 partial transection, and type 4 complete transection. The initial management of radial nerve palsies associated with closed fractures of the humerus remains a controversial topic, with early exploration reserved for open fractures, fractures that cannot achieve an adequate closed reduction requiring fracture repair, fractures with associated vascular injuries, and polytrauma patients. Outside of these recommendations, expectant observation for spontaneous recovery is recommended.

[Compression syndrome of the radial nerve in the area of the supinator groove. Experiences with 110 patients]

Both radial tunnel syndrome and posterior interosseous nerve (PIN) compression syndrome are caused by compression of the posterior interosseous nerve. There is a controversy about certain features of PIN compression especially with regard to diagnostic criteria and therapy as well as differentiation from tennis elbow. From 1992 to 1997, we operated 110 patients because of PIN compression. Diagnosis was based on clinical examination only. As a rule, we decompressed the PIN directly using an anterior approach. With regard to radial tunnel syndrome, we could review 69 from 103 operations with an average follow-up of 41 months. Using the criteria originally proposed by Roles and Maudsley, only 60% showed excellent or good results. The mean DASH score was 32. Recompression of the PIN by scarring was found in as much as 17% of patients and proved to be a serious complication of direct decompression of the PIN. Furthermore, 52% of our patients operated on because of PIN compression suffered from tennis elbow as well. We therefore believe that radial tunnel syndrome is a specific form of tennis elbow. From an anatomical point of view, the inseparable origin of the radial wrist extensors and supinator muscle seems to link tennis elbow and radial tunnel syndrome. To avoid recompression of the PIN by scarring, we have abandoned direct decompression and now routinely use Wilhelm's denervation procedure for the treatment of tennis elbow as well as radial tunnel syndrome. This procedure indirectly decompresses the PIN by cutting the superficial origin of the supinator muscle with consecutive relaxation of Frohse's arcade. Preliminary results are promising and show improvement of preoperative neurologic status by indirect decompression.

Radial tunnel syndrome in an elite power athlete: a case of direct compressive neuropathy

Radial tunnel syndrome (RTS) is thought to result from intermittent and dynamic compression of the posterior interosseous nerve (PIN) in the proximal part of the forearm associated with repeated supination and pronation. The diagnostic criteria encompassing RTS are purely clinical and the term "radial tunnel syndrome" has become controversial because of the lack of focal motor weakness in the majority of patients diagnosed with RTS. Retrospective cadaveric and surgical studies have revealed several areas within the forearm in which the PIN may become entrapped. Recent studies have suggested that the PIN is "fixed" in the supinator muscle and that wrist pronation is the actual movement that places the most stress on the PIN. The patients most often afflicted with RTS appear to be those who perform repetitive manual tasks involving rotation of the forearm and athletes involved in racket sports. Surgical exploration with decompression of the PIN is often required in patients with RTS. We present the first case of RTS occurring in an elite power athlete and believe this case represents a direct compressive sensory neuropathy. The optimum nonsurgical treatment plan for the elite athlete in training for competition and the cause of this compressive neuropathy in power athletes will be discussed.