Radial tunnel release. Unpredictable outcome in 37 consecutive cases with a 1-5 year follow-up

Establishing the diagnosis of radial tunnel syndrome: a systematic review of published clinical series

PURPOSE

Radial tunnel syndrome (RTS) is a controversial diagnosis due to non-specific exam findings and frequent absence of positive electromyography (EMG) and nerve conduction study (NCS) findings. The purpose of this study was to identify the methods used to diagnose RTS in the literature.

METHODS

We queried PubMed, Embase, Web of Science, and Cochrane databases per PRISMA guidelines. Extracted data included article and patient characteristics, diagnostic assessments utilized and their respective findings, and treatments. Objective data were summarized descriptively. The relationship between reported diagnostic findings (i.e., physical exam and diagnostic tests) and treatments was assessed via a descriptive synthesis.

RESULTS

Our review included 13 studies and 391 upper extremities. All studies utilized physical exam in diagnosing RTS; most commonly, patients had tenderness over the radial tunnel (381/391, 97%). Preoperative EMG/NCS was reported by 11/13 studies, with abnormal findings in 8.9% (29/327) of upper extremities. Steroid and/or lidocaine injection for presumed lateral epicondylitis was reported by 9/13 studies (46/295 upper extremities, 16%), with RTS being diagnosed after patients received little to no relief. It was also common to inject the radial tunnel to make the diagnosis (218/295, 74%). The most common reported intraoperative finding was narrowing of the PIN (38/137, 28%). The intraoperative compressive site most commonly reported was the arcade of Frohse (142/306, 46%).

CONCLUSIONS

There is substantial heterogeneity in modalities used to diagnose RTS and the reported definition of RTS. This, in conjunction with many patients having concomitant lateral epicondylitis, makes it difficult to compare treatment outcomes for RTS.

LEVEL OF EVIDENCE

Level III. Systematic review of retrospective and prospective cohort studies.

Demographics of Common Compressive Neuropathies in the Upper Extremity

BACKGROUND

The purpose of this study was to compare the demographic differences of the most common peripheral nerve compressions in the upper extremity-carpal tunnel syndrome (CTS), ulnar nerve compression (UNC) at the elbow, combined CTS and UNC, radial tunnel syndrome (RTS), and posterior interosseous nerve syndrome (PINS)-as a means to better understand the etiologies of each.

METHODS

A retrospective chart review was performed of all patients over the age of 18 years seen at our institution in the 2018 calendar year. International Classification of Diseases, Tenth Revision codes were used to identify patients with diagnoses of upper extremity peripheral nerve compressions. Demographic details and relevant comorbidities were recorded for each patient and compared with controls, who were seen the same calendar year with no neuropathies. χ2 analyses, independent-samples t tests, and multivariate logistic regressions were performed (P < .05).

RESULTS

A total of 7448 patients were identified. Those with CTS were mainly women, former smokers, and diabetic (all P < .001) and with a greater average body mass index (BMI) (P = .006) than controls. Patients with UNC were more often men and younger when compared with controls (both P < .001). A history of smoking, diabetes, and average BMI were similar between patients with UNC and controls (all P > .05). Those patients with combined CTS/UNC were mainly men, former smokers, and diabetic (all P < .001) when compared with controls. Patients with RTS/PINS were also mostly men (P = .007), diabetic (P = .042), and were more often current smokers (P < .001).

CONCLUSIONS

The demographics of patients with various compressive neuropathies were not homogeneous, suggesting different etiologies.

The Epidemiology of Radial Tunnel Syndrome and Its Overlap With Lateral Epicondylitis

PURPOSE

Radial tunnel syndrome (RTS) is characterized by nerve compression affecting the posterior interosseous nerve branch in the forearm, and its symptoms often overlap with those of lateral epicondylitis (LE). The purpose of this study was to examine the epidemiology of RTS, frequency of injections and surgical release, and overlap of RTS with LE.

METHODS

We queried the PearlDiver database to identify RTS in patients older than 18 years. Demographic data, diagnostic or therapeutic injection within 30 days of diagnosis, surgical release within 1 year of diagnosis, and 90-day postoperative complication rates were evaluated. Using International Classification of Diseases, 10th Revision, laterality codes, we also determined the number of patients who had same-side RTS and LE and the proportion of patients who subsequently underwent simultaneous RT release and LE debridement.

RESULTS

The prevalence of RTS in a representative United States insurance database was 0.091%, and the annual incidence was 0.0091%. There were 75,459 patients identified with an active RTS diagnosis. The mean age at the time of diagnosis was 52 years (range, 18-81 years), 55% were women, and 1,833 patients (2.4%) underwent RT release within 1 year. Fewer than 3% of the patients received an injection within 30 days of RTS diagnosis. The 90-day postoperative complication rates were low: 5% of the patients required hospital readmission and 2.1% underwent revision surgery. Approximately 5.7% of the patients with RTS also had a diagnosis of LE on the same side within 6 months of RTS diagnosis. In patients with ipsilateral RTS and LE who underwent surgery, 59.1% underwent simultaneous RT release and LE debridement, whereas 40.9% underwent isolated radial tunnel release.

CONCLUSIONS

The analysis of a large insurance database showed that the diagnosis of RTS is rarely assigned, suggesting that the incidence of this nerve compression is low.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Ultrasound-Guided Hydrodissection Provides Complete Symptom Resolution in Radial Tunnel Syndrome: A Case Series and Scoping Review on Hydrodissection for Radial Nerve Pathology

ABSTRACT

This study analyzes the effectiveness of ultrasound-guided hydrodissection (HD) perineural as a treatment for radial tunnel syndrome (RTS). A literature search was performed along with retrospective analysis of local cases to assess outcomes and safety of this procedure. In the case series, surgical candidates, defined as cases with over 80% but temporary relief after diagnostic injection, were treated with ultrasound-guided HD. Of 22 patients who received ultrasound-guided diagnostic injections, 11 proceeded to HD. All HD patients experienced complete and lasting symptom resolution for a minimum of 2 years, and none required surgery. Thorough literature review provided seven studies, which fulfilled inclusion criteria. Sixty-one patients are represented in the literature. All studies reported significant benefit to pain symptoms with HD of radial nerve, with five specifying over 90% improvement. No adverse effects from HD were noted in any study. Ultrasound-guided HD of the radial tunnel has potential to be a surgery sparing treatment for RTS.

A Combined Revision Surgical Technique for Failed Operative Lateral Epicondylitis With Concomitant Radial Tunnel Syndrome

Lateral epicondylitis afflicts a large percentage of the population with most recovering through conservative treatment. The 5% to 10% of patients who undergo operative intervention are met with mixed results. Those that fail to improve often demonstrate a complex presentation of inadequate debridement of the "angiofibroblastic tissue," missed concomitant radial tunnel syndrome, and iatrogenic residual devascularized tissue resulting from the index procedure. To address all 3 of these causes of failure, the authors have developed a revision procedure that includes repeat debridement of residual tendinosis, decompression of the posterior interosseous nerve, and a vascularized anconeus muscle flap to help cushion soft tissue defects and promote a healthier environment for healing. Performed initially in part in 20 patients, this combined procedure has developed into our recommended treatment for these challenging patients.

Compression neuropathies of the forearm: anatomy, clinical features and management

The upper limb consists of four major parts: a girdle formed by the clavicle and scapula, the arm, the forearm and the hand. Peripheral nerve lesions of the upper limb are divided into lesions of the brachial plexus or the nerves arising from it. Lesions of the nerves arising from the brachial plexus are further divided into upper (proximal) or lower (distal) lesions based on their location. Peripheral nerves in the forearm can be compressed in various locations and by a wide range of pathologies. A thorough understanding of the anatomy and clinical presentations of these compression neuropathies can lead to prompt diagnosis and management, preventing possible permanent damage. This article discusses the aetiology, anatomy, clinical presentation and surgical management of compressive neuropathies of the upper limb.

Occupational biomechanical risk factors for radial nerve entrapment in a 13-year prospective study among male construction workers

Objectives

The aim was to assess the association between occupational biomechanical exposure and the occurrence of radial nerve entrapment (RNE) in construction workers over a 13-year follow-up period.

Methods

A cohort of 229 707 male construction workers who participated in a national occupational health surveillance programme (1971–1993) was examined prospectively (2001–2013) for RNE. Height, weight, age, smoking status and job title (construction trade) were obtained on health examination. RNE case status was defined by surgical release of RNE, with data from the Swedish national registry for out-patient surgery records. A job exposure matrix was developed, and biomechanical exposure estimates were assigned according to job title. Highly correlated exposures were summed into biomechanical exposure scores. Negative binomial models were used to estimate the relative risks (RR) (incidence rate ratios) of RNE surgical release for the biomechanical factors and exposure sum scores. Predicted incidence was assessed for each exposure score modelled as a continuous variable to assess exposure–response relationships.

Results

The total incidence rate of surgically treated RNE over the 13-year observation period was 3.53 cases per 100 000 person-years. There were 92 cases with occupational information. Increased risk for RNE was seen in workers with elevated hand-grip forces (RR=1.79, 95% CI 0.97 to 3.28) and exposure to hand-arm vibration (RR=1.47, 95% CI 1.08 to 2.00).

Conclusions

Occupational exposure to forceful handgrip work and vibration increased the risk for surgical treatment of RNE.

Common Entrapment Neuropathies

PURPOSE OF REVIEW

This article addresses relevant peripheral neuroanatomy, clinical presentations, and diagnostic findings in common entrapment neuropathies involving the median, ulnar, radial, and fibular (peroneal) nerves.

RECENT FINDINGS

Entrapment neuropathies are a common issue in general neurology practice. Early diagnosis and effective management of entrapment mononeuropathies are essential in preserving limb function and maintaining patient quality of life. Median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, radial neuropathy at the spiral groove, and fibular neuropathy at the fibular head are among the most frequently encountered entrapment mononeuropathies. Electrodiagnostic studies and peripheral nerve ultrasound are employed to help confirm the clinical diagnosis of nerve compression or entrapment and to provide precise localization for nerve injury. Peripheral nerve ultrasound demonstrates nerve enlargement at or near sites of compression.

SUMMARY

Entrapment neuropathies are commonly encountered in clinical practice. Accurate diagnosis and effective management require knowledge of peripheral neuroanatomy and recognition of key clinical symptoms and findings. Clinical diagnoses may be confirmed by diagnostic testing with electrodiagnostic studies and peripheral nerve ultrasound.

DIAGNOSIS AND TREATMENT OF POSTERIOR INTEROSSEOUS NERVE ENTRAPMENT: SYSTEMATIC REVIEW

Compressive syndromes of the radial nerve have different presentations. There is no consensus on diagnostic and therapeutic methods. The aim of this review is to summarize such methods. Eletronic searches related terms, held in databases (1980-2016): Pubmed (via Medline), Lilacs (via Scielo) and Google Scholar. Through pre-defined protocol, we identified relevant studies. We excluded case reports. Aspects of diagnosis and treatment were synthesized for analysis and tables. Quantitative analyzes were followed by their dispersion variables. Fourteen studies were included. All studies were considered as level IV evidence. Most studies consider aspects of clinical history and provocative maneuvers. There is no consensus on the use of electromyography, and methods are heterogeneous. Studies have shown that surgical treatment (muscle release and neurolysis) has variable success rate, ranging from 20 to 96.5%. Some studies applied self reported scores, though the heterogeneity of the population does not allow inferential analyzes on the subject. few complications reported. Most studies consider the diagnosis of compressive radial nerve syndromes essentially clinical. The most common treatment was combined muscle release and neurolysis, with heterogeneous results. There is a need for comparative studies. Level of Evidence III, Systematic Review.

Uncommon upper extremity compression neuropathies

Hand surgeons routinely treat carpal and cubital tunnel syndromes, which are the most common upper extremity nerve compression syndromes. However, more infrequent nerve compression syndromes of the upper extremity may be encountered. Because they are unusual, the diagnosis of these nerve compression syndromes is often missed or delayed. This article reviews the causes, proposed treatments, and surgical outcomes for syndromes involving compression of the posterior interosseous nerve, the superficial branch of the radial nerve, the ulnar nerve at the wrist, and the median nerve proximal to the wrist.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

Radial tunnel syndrome

Radial tunnel syndrome is a pain syndrome resulting from compression of the posterior interosseous nerve at the proximal forearm. It has no specific radiologic or electrodiagnostic findings. Treatment should be started conservatively; if not successful, surgical treatment is indicated. The posterior interosseous nerve may be explored through dorsal or anterior approaches. All the potential sites of entrapment should be released, including complete release of the superficial head of the supinator muscle. Surgical treatment is generally successful, but patients who have associated lateral epicondylitis or those who are involved in workers' compensation claims have less successful outcomes.

Piriformis syndrome surgery causing severe sciatic nerve injury

Piriformis syndrome is a controversial entrapment neuropathy in which the sciatic nerve is thought to be compressed by the piriformis muscle. Two patients developed severe left sciatic neuropathy after piriformis muscle release. One had a total sciatic nerve lesion, whereas the second had a predominantly high common peroneal nerve lesion. Follow-up studies showed reinnervation of the hamstrings only. We conclude that piriformis muscle surgery may be hazardous and result in devastating sciatic nerve injury.

Unusual compression neuropathies of the forearm, part I: radial nerve

Peripheral compression neuropathies are familiar to the hand surgeon. Although compression neuropathies of the forearm are far less common than those of the wrist (namely, carpal tunnel syndrome), for the patient suffering from one of these neuropathies, a missed diagnosis has far-reaching consequences. In this 2-part review (I: Radial Nerve; II: Median Nerve), several compression neuropathies of the forearm are examined. We will first discuss compression neuropathies affecting the radial nerve: (1) posterior interosseous nerve syndrome, (2) radial tunnel syndrome, and (3) superficial radial nerve compression (Wartenberg's syndrome).

Radial tunnel syndrome: emphasis on the superficial branch of the radial nerve

Reported success rates for decompressing the radial nerve in patients with radial tunnel syndrome vary between 10 and 95%. The combined treatment, releasing both the posterior interosseous nerve and the superficial branch of the radial nerve, has been described only three times, but seems to show more consistent success rates compared with releasing the posterior interosseous nerve alone. We present the results of decompressing the superficial branch of the radial nerve only, the anatomical basis for this approach and a description of the surgical technique. Our results are comparable to the results of the combined treatment. Eleven of 12 patients were satisfied with the results of the operation. This study indicates that pain in patients with radial tunnel syndrome may be treated successfully by surgical decompression of the superficial branch of the radial nerve.

Long term results of radial tunnel release – the effect of co-existing tennis elbow, multiple compression syndromes and workers' compensation

SUMMARY

Surgical decompression of radial tunnel syndrome (RTS) remains controversial because the results are unpredictable. This study is a retrospective analysis of the long term outcomes of RTS release and a comparison of our findings with previous studies. Thirty-three extremities in 31 patients underwent decompression for radial tunnel syndrome between 1994 and 2003, of which 27 extremities in 25 patients were available for long term follow up after an average of 57 months (range 16 to 106 months). Outcomes were evaluated using the criteria of Ritts et al. (1987). For 16 patients (18 of 27 extremities), the outcome was rated as good (67%), for four patients (four extremities) as fair (15%), and for five patients (five extremities) as poor (18%). The outcome was better in patients with simple RTS (86% good results) compared with patients with additional nerve compression syndromes (57% good results), or patients with coexisting lateral epicondylitis (70% vs 43% good results), or patients who were receiving workers' compensation (73% vs 58% good results). One-third of patients still had moderate or severe disability which affected their ability to work, but 82% had relief of their pain. Surgical decompression is therefore beneficial for simple RTS, but may be less successful if there are co-existing additional nerve compression syndromes or lateral epicondylitis or if the patient is receiving workers'compensation.

Interventions for treating the radial tunnel syndrome: a systematic review of observational studies

PURPOSE

For some disorders, such as radial tunnel syndrome (RTS), no randomized controlled trials and controlled clinical trials are available. To gain insight into the effectiveness of conservative and surgical interventions for treating RTS, we systematically reviewed all available observational studies on treatment of RTS. Although the validity of case series is inferior to that of controlled trials, the case series might provide valuable data about the efficacy of treatment options.

METHODS

A literature search and additional reference checking resulted in 21 eligible case series for this review. Based on previous checklists, we constructed a new quality assessment and rating system to analyze the included case series. The methodological quality was assessed, and data extraction was performed. Studies with less than 50% of the maximum points on the methodological quality assessment were considered inadequate and were excluded from the analysis. To summarize the results according to the rating system for the strength of the scientific evidence for these case series, we introduced 4 levels: (1) tendency, (2) slight tendency, (3) conflicting tendency, and (4) no tendency.

RESULTS

After the methodological quality assessment, 6 articles were included in the final analysis. They all reported on surgical treatment.

CONCLUSIONS

There is a tendency that surgical decompression of the radial tunnel might be effective in patients with RTS. The effectiveness of conservative treatments for RTS is unknown because, for most treatments, no studies were available. Additional high-quality controlled studies are needed to assess the level of conclusive evidence for surgical treatment and also to evaluate conservative treatments for RTS. For this, we recommend a multicenter, randomized clinical trial. Due to the lack of a clear protocol for diagnosing RTS, a reliable and valid diagnostic tool should be developed.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A unified approach to radial tunnel syndrome and lateral tendinosis

Two of the most common diagnoses assigned to patients presenting with lateral elbow and proximal forearm pain are lateral tendinosis and radial tunnel syndrome. Traditionally, these 2 conditions have been treated as distinct and separate entities with most patients being diagnosed with either one or the other, but not both. The extensor carpi radialis brevis (ECRB) and, to a lesser the degree, a portion of the extensor digitorum communis that form the conjoined lateral extensor tendon are thought to be primarily responsible for the excessive traction that induces lateral tendinosis (a degenerative process of microtears in the tendon with impaired healing), but the supinator blends with these same fibers and shares a role in the pathology. The supinator, primarily the arcade of Frohse, has been thought to play the majority role in compressing the posterior interosseous nerve in radial tunnel syndrome, but the undersurface thick tendon of the ECRB may also cause substantial nerve compression. Reduction of the linear tension transmitted by the ECRB is the common element in the various surgical treatments for lateral tendinosis, performed anywhere from directly at the lateral epicondyle to the distal myotendinous junction. Nerve decompression by division of fascial bands is the goal in surgery for radial tunnel syndrome. These 2 surgical approaches need not be mutually exclusive. In fact, this separation of the 2 clinical entities may play a role in the unpredictable results reported in the literature. This article presents a unified approach to treating both pathologies simultaneously including short-term clinical results.

Anatomy of the posterior antebrachial cutaneous nerve: practical information for the surgeon operating on the lateral aspect of the elbow

PURPOSE

To investigate the anatomic relationships of the posterior antebrachial cutaneous nerve (PABCN) to anatomic landmarks on the lateral side of the elbow.

METHODS

The PABCN was explored in 30 cadaveric upper extremities. Distances were noted from easily identifiable structures including the lateral epicondyle, the lateral intermuscular septum, and the radial nerve.

RESULTS

The path of the PABCN follows the spiral groove initially, diverging as the radial nerve pierces the lateral intermuscular septum. The PABCN emerges from the posterior compartment through a hiatus in the deep fascia at a mean of 6.6 cm proximal to the lateral epicondyle and passes a mean of 2.1 cm anterior to the lateral epicondyle.

CONCLUSIONS

The anatomic relationships determined in this study should enable the surgeon to avoid injuring the PABCN when performing surgery in the lateral elbow region.

Painful neuroma of the posterior cutaneous nerve of the forearm after surgery for lateral humeral epicondylitis

PURPOSE

To describe a neuroma of the posterior cutaneous nerve of the forearm that can be the source of pain after surgery for lateral humeral epicondylitis.

METHODS

A retrospective chart review of 9 patients having pain after surgery for lateral humeral epicondylitis was conducted to evaluate their history of pain, surgical findings during exploration of their painful lateral elbow scar, and outcome of their surgical treatment.

RESULTS

In each of the 9 patients a neuroma of the posterior cutaneous nerve of the forearm was found to be within the scar of the original lateral epicondylitis surgery. For each of these patients the surgical treatment included resection of the neuroma and implantation of the proximal end of the nerve into the brachioradialis muscle proximal to the elbow joint. With this approach 8 of the patients had excellent pain relief and 1 had good pain relief at a mean follow-up time of 1.4 years (range, 1.0-2.6 years).

CONCLUSIONS

Pain in the region of the scar after surgery to treat lateral humeral epicondylitis can be caused by a neuroma of the posterior cutaneous nerve of the forearm and this painful neuroma can be treated successfully by neuroma resection and implantation of the nerve proximally into the brachioradialis muscle.

Radial tunnel syndrome caused by ganglion cyst: treatment by arthroscopic cyst decompression

Compressive neuropathies of the radial nerve at the elbow can lead to one of 2 clinical entities. Posterior interosseous syndrome is primarily a motor deficiency of the posterior interosseous nerve, and radial tunnel syndrome presents as pain along the radial tunnel and extensor muscle mass. The radial nerve can be compressed at a number of sites around the elbow. In addition, numerous mass lesions reported in the literature can cause compressive neuropathy of the radial nerve at the elbow. Standard surgical management for persistent radial tunnel syndrome that is refractory to nonsurgical treatment is open decompression of the radial nerve. Cysts occurring in other joints are commonly treated arthroscopically. Supraglenoid cysts of the shoulder, meniscal cysts in the knee, and dorsal wrist ganglia are routinely treated with arthroscopic decompression or excision with management of the underlying etiology of the cyst. We present a case of radial tunnel syndrome caused by a ganglion cyst of the proximal radioulnar joint that was treated using arthroscopic excision of the cyst and decompression of the radial nerve.

Facteurs de risque professionnels du syndrome du tunnel radial chez les salariés de l’industrie de production de masse

STUDY

The purpose of the study was to evaluate the professional and extraprofessional risk factors for radial tunnel syndrome (RTS) in employees of three large companies.

METHOD

Twenty-one cases of RTS were compared to 21 controls, matched for age, sex, and activity. In nine cases, RTS was associated with carpal tunnel syndrome. The analysis considered medical history, extraprofessional activity, and the ergonomic and organisational aspects of work.

RESULTS

The study demonstrated three risk factors of RTS related to work conditions. The regular use of a force of at least 1 kg (OR = 9.1 (1.4-56.9)) more than 10 times per hour is the main biomechanical risk factor. Static work (OR = 5.9 (1.2-29.9)) as well as work with the elbow constantly extended 0 degree to 45 degrees, is strongly associated with an increased risk of RTS (OR = 4.9 (1.0-25.0)). Complete extension of the elbow associated with pronation and supination of the forearm may cause trauma to the radial nerve in the radial tunnel. On the other hand, we found no personal factors and no extraprofessional activities which were associated with an increased risk of RTS.

CONCLUSIONS

This study shows that motions of the forearm requiring intense effort and performed with the elbow in extension and the forearm in pronation and supination increase the risk of RTS.

Nerve entrapments of the upper extremity: A surgical perspective

The surgeon's perspective of nerve entrapment lesions in the upper extremity is discussed in this article. The focus is on the most common lesions of the median, ulnar, and radial nerves. An understanding of the anatomy and the potential pathologies provide the basis for surgical treatment. Current treatment protocols are discussed with the authors' recommendations that are based upon experience and literature review.

Radial neuropathy

The radial nerve is the largest branch of the brachial plexus, and is commonly involved in upper extremity mononeuropathies. The radial nerve is primarily responsible for motor innervation of the upper extremity extensors, as well as receiving cutaneous innervation from most of the posterior arm, forearm, and hand. There are a variety of sites at which the radial nerve is susceptible to trauma and entrapment. Localizing radial nerve lesions is dependent on clinical knowledge of radial nerve anatomy, and sensory and motor examination.

Disputed radial tunnel syndrome

True neurogenic radial tunnel syndrome is an uncommon condition caused by entrapment of the radial or posterior interosseous nerve in the radial tunnel and is usually easily identifiable by focal motor weakness in the distribution of the posterior interosseous nerve. Roles and Maudsley, analogizing to carpal tunnel syndrome, believed "radial tunnel syndrome" had a different presentation: proximal forearm pain and tenderness in the region of the supinator muscle. However, their patients lacked weakness or other neurologic deficit. They and subsequent surgeons have decompressed the radial nerve to treat forearm pain and tenderness, even though it is debatable whether radial nerve entrapment causes the forearm discomfort. The term "radial tunnel syndrome" is best reserved for the truly neurogenic cases. Surgical approaches to "persistent tennis elbow" should be assessed in a controlled fashion, rather than adopted on the basis of a flawed analogy to carpal tunnel syndrome.

Radial tunnel syndrome: diagnosis and management

This study presents a review of 26 cases of radial tunnel syndrome in 25 patients seen in a single hand consultant's practice over a period of 2.5 years. The protocol for diagnosis was the reproduction of patient's symptoms on pressure over a palpable tender spot along the course of the radial tunnel, painful resisted supination or resisted middle finger extension, all of which were abolished on infiltration of the tender area with a local anaesthetic solution. The presence of at least two out of three objective signs was necessary for the diagnosis. Initially all cases were treated conservatively, by steroid injection in 25 and physiotherapy in one, with long-term relief of pain in 16. Nine failures were treated surgically, with complete relief of pain in seven. Radial tunnel syndrome should be considered in the differential diagnosis of pain around the hand and or elbow.

Differential latency testing: a more sensitive test for radial tunnel syndrome

A modification of the standard electrodiagnostic test was developed in an effort to provide a more sensitive electrodiagnostic evaluation in radial tunnel syndrome. Radial motor nerve latency recordings were obtained in 3 different forearm positions: neutral, passive supination, and passive pronation. The maximal difference in these recordings, the differential latency, in 25 patients with radial tunnel syndrome of greater than 6 months duration (test group) was compared with those in 25 asymptomatic volunteers (control group). Differential latency recordings were obtained in all patients in the test group before and after surgery. Radial nerves that were compressed demonstrated a significantly greater differential latency (0.44+/-0.12 ms) versus controls (0.12+/-0.008 ms). Following radial nerve decompression, differential motor latencies in the test group decreased below control values, demonstrating a resolution of the provoked electrical response with a postoperative differential latency of 0.07+/-0.05 ms. Our results demonstrate the differential motor latency of the radial nerve to be a sensitive electrodiagnostic tool in patients with radial tunnel syndrome. A differential latency of > or =0.30 ms was considered indicative of radial tunnel syndrome.