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High-resolution 3T MR neurography of radial neuropathy
Abstract
The radial nerve is a continuation of the posterior cord of the brachial plexus and one of the major nerves that provide motor and sensory innervations to the forearm. MR imaging evaluation of the radial nerve pathology has been described in scattered case reports. Current high-field MR scanners enable high resolution and high contrast imaging of the peripheral nerves. This article reviews the 3 Tesla magnetic resonance neurography imaging of radial nerve anatomy and various pathologies affecting it with relevant case examples.
... The only areas prone to magic-angle artifacts are in the axilla and PIN as it traverses through the supinator muscle. 3,7,50 At the latter sites, however, the signal intensity of the normal nerve does not approach the adjacent in-plane veins. Patients with neuropathy show abnormal vessel-like PIN hyperintensity at the entrapment or injury site, with or without enlargement of the nerve. ...
... Radial tunnel syndrome, on the other hand, is a distinct clinical but controversial entity, often occurring as the result of repetitive motion injuries to the elbow, and is distinguished by the general absence of motor weakness. 49,50 Patients typically report pain in the region of the proximal extensor and supinator muscles, exacerbated by forearm pronation, extension of the elbow, and flexion of the wrist. 46,47 ...
... Although ultrasonography is currently the modality of choice for evaluating the superficial sensory branch or for detection of a commonly offending mass lesion such as a ganglion cyst, technological advances in high-resolution MR neurography allow demonstration of the abnormal nerve appearance, regional joint abnormality, and characterization of the soft-tissue lesion, if present. 50,51 The accurate localization of the nerve compression is a key factor in making a decision on the possibility, and planning, of the surgical approach. 50 MR neurography allows excellent anatomic imaging of radial nerve entrapment with an added capability of demonstrating structural lesions along the course of the affected nerve (Fig. 13). ...
The most common sites of nerve entrapment are in the upper extremity, commonly diagnosed based on clinical findings and electrophysiologic studies. Cross-sectional imaging modalities, such as ultrasonography and magnetic resonance (MR) imaging, have been used to enhance diagnostic accuracy and provide anatomic mapping of abnormalities. MR neurography offers multiplanar high-resolution imaging of upper extremity nerves as well as adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy and related abnormalities. This article reviews the normal 3-T MR neurographic appearance of the upper extremity nerves, and abnormal findings related to injury, entrapment, and other pathologic conditions.
... eration after the treatment of suprascapular neuropathy. Although abnormal neuromuscular electrophysiology findings can suggest neuropathy, the exact cause and localization of the lesion are often not apparent on these examinations for determining whether the finding is nerve compression, injury, or a mass lesion [4][5][6]. Additionally, a negative result does not exclude the diagnosis of suprascapular neuropathy [7]. MRI, specifically MR neurography (MRN), is an invaluable diagnostic tool in this setting. ...
... The current state of the art for imaging relatively small anatomic structures, such as ligaments and peripheral nerves, is 3.0-T MRI, which enables high resolution and excellent softtissue contrast. MRN has been increasingly used to further evaluate cases of suspected or established suprascapular neuropathy and other peripheral neuropathies with excellent results [4][5][6][7]. This article illustrates the regional anatomy and various abnormalities involving the suprascapular nerve, with description of the respective imaging findings at 3-T MRN (Appendix 1). ...
OBJECTIVE. In this article, we will review the normal anatomy and imaging features of various neuromuscular abnormalities related to suprascapular neuropathy. CONCLUSION. Suprascapular neuropathy can be difficult to distinguish from rotator cuff pathology, plexopathy, and radiculopathy. Electrodiagnostic studies are considered the reference standard for diagnosis; however, high-resolution 3-T MR neurography (MRN) can play an important role. MRN enables direct visualization of the nerve and simultaneous assessment of the cervical spine, brachial plexus, and rotator cuff.
... The portion that exits the supinator muscle is known as the posterior interosseous nerve (PIN) while the superficial branch is in between the supinator and brachioradialis muscles [16]. PIN compression tends to appear as an abnormal T2 hyperintensity that most often occurs at the arcade of Frohse (a low signal band at the proximal edge of the supinator muscle) [31,32]. Other sites of compressions of PIN and radial nerve are at the bicipital bursa and the distal edge of the supinator [33]. ...
Elbow derangements are common. Clinical examination is supplemented by magnetic resonance imaging (MRI) for optimal diagnostic assessment of such disorders. 3-dimensional (3D) imaging is feasible on newer MR scanners in acceptable acquisition times. Isotropic high-resolution 3D MRI affords multiplanar reconstructions and aids in diagnostic evaluation of elbow disorders and pre-/post-surgical assessments. The article details technical considerations of 3D elbow MRI and discusses its role in diagnostic evaluation of elbow disorders with relevant comparisons to 2D MRI and emphasizes as to how such advanced imaging assists in pre- and post-surgical assessments of tendon and ligament derangements.
... Uncommonly, the tumor may involve the neurovascular bundles and cause pain or tenderness [4,5]. However, primary growth along a peripheral nerve and presentation as mononeuropathy or a mass-like lesion is extremely rare [6][7][8]. Because of its slow growth and nodular pattern, it is often mistaken for various other entities [9]. ...
The authors report an unusual case of radial mononeuropathy caused by epithelioid sarcoma and describe the anatomical 3-Tesla MR neurography and the functional diffusion tensor imaging findings of the case, which were subsequently confirmed on surgical excision and histopathology.
Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies
Until recently, imaging of peripheral nerves was limited from a technical point of view, as there was no established gold standard study protocol for the purpose of qualitative visualization of nerve trunks in normal and pathological conditions. With technical advances in magnetic resonance imaging and the advent of specialized high-resolution magnetic resonance neurography, it has become possible to visualize peripheral nerves of varying diameters. A literature search in the Pubmed, Medline, EMBASE, Cochrane Library, and eLibrary databases demonstrated the presence of several studies examining the capabilities of magnetic resonance imaging in visualizing the pudendal nerve in normal and pathological conditions. It must be emphasized that the results of these studies are consistent and largely complement each other. A generalization of the available data on the capabilities of magnetic resonance neurography of the pudendal nerve was the impetus for writing this literature review. Magnetic resonance neurography is a tissue-specific imaging method optimized for assessing the condition of peripheral nerves, including changes in the morphology of their bundle structure, signal, the diameter and length of nerve trunks, which can be caused by both anatomical features and pathological processes. Three-dimensional (3D) imaging is critical for studying the topography of peripheral nerves, identifying areas of compression or traumatic injury, and for preoperative planning. Magnetic resonance imaging in certain modes and sections allows to clearly visualize the pudendal nerve along almost its entire length, determine the nature of its branching and the features of its topographic and anatomical location. The anatomical characteristics of the pudendal nerve and its pathological changes obtained using magnetic resonance neurography can be used in everyday clinical practice by urologists, obstetricians-gynecologists and neurosurgeons for planning surgical interventions.
Neuropathic pain is a complex syndrome rather than a simple symptom. Definite diagnosis of neuropathic pain requires objective evidence of somatosensory system dysfunction. Numerous tools are available to assess neuropathic pain, but the diagnostic workup should be tailored for each patient according to the clinical status and the provisional diagnosis. The diagnostic tests of neuropathic pain include neurophysiological tests which provide functional assessment, skin and nerve biopsy which provide microscopic assessment, neuroimaging which provide structural and anatomical assessment, in addition to laboratory and genetic testing. Each tool has its own advantages and limitations, thus there is no single gold standard diagnostic test for neuropathic pain. A combination of tests is usually required, and the successful cost-effective diagnosis of neuropathic pain depends on the wise selection of the diagnostic tests from the available toolbox. This chapter provides an overview of the most important and valuable diagnostic tests for neuropathic pain.KeywordsNeuropathic painElectrodiagnosisEvoked potentialsSkin biopsyNerve biopsyNeuromuscular ultrasoundMagnetic resonance neurography
Neuropathic pain is a complex and challenging secondary pain condition. It is a sequela of central nervous or peripheral nervous system lesions and pathologies. It can be debilitating and affects approximately 7% of the general population. Many factors contribute to the development of this chronic neuropathic pain. It can originate from the central part of the nervous system as a result of brain or spinal cord injury, stroke, or multiple sclerosis. Peripheral neuropathic pain manifests in the peripheral nervous system, and includes large fiber and small fiber polyneuropathy, radiculopathy, and mononeuropathy. Pharmacological options include tricyclic antidepressants (TCA), serotonin and norepinephrine reuptake inhibitors (SNRI), and gabapentinoids. For more severe cases, interventional pain management techniques such as peripheral nerve blocks, spinal cord, or peripheral nerve stimulation may be reasonable options.
Conditions affecting the musculoskeletal system constitute a significant portion of medical emergencies in the United States, with traumatic injury and infection being two of the most common etiologies. Although physical examination and plain radiographs are often sufficient to guide diagnosis and treatment, there are myriad traumatic and infectious pathologies that are commonly missed or simply not detectable on plain radiographs. Advanced imaging is subsequently warranted for additional workup.
Magnetic resonance imaging (MRI) has become an increasingly used imaging modality for musculoskeletal complaints in the emergency department due to its superior visualization of soft tissues, focal edematous changes, and occult osseous insults often not visible on plain radiographs. Although multiple studies have evaluated its utility in the workup of emergency musculoskeletal complaints, there remains a dearth of literature examining the use of MRI for certain occult diagnoses.
Radiologists, emergency clinicians, and orthopedic surgeons must be knowledgeable of the indications for MRI in the emergency setting, as delayed diagnosis may contribute to increased morbidity and possibly mortality. This review summarizes the use of MRI in diagnoses relating to trauma or infection among patients presenting to the emergency department with a musculoskeletal complaint.
High radial palsy is primarily associated with humeral shaft fractures, whether primary due to the initial trauma, or secondary to their treatment. The majority will spontaneously recover, therefore early surgical exploration is mainly indicated for open fractures or if ultrasonography shows severe nerve damage. Initial signs of nerve recovery may appear between 2 weeks and 6 months. Otherwise, the decision to explore the nerve is based on the patient's age, clinical examination and electroneuromyography, as well as ultrasonography findings. If recovery does not occur, an autograft is indicated only in younger patients, before 6 months, if local conditions are suitable. Otherwise, nerve transfers performed by an experienced team give satisfactory results and can be offered up to 10 months post-injury. Tendon transfers are the gold standard treatment and the only option available beyond 10 to 12 months. The results are reliable and fast.
The entire shoulder and arm nerves are detailed as far as they can be involved by focal lesion entrapment. Anatomy, variants, damaging factors, patient’s presentation of clinical symptoms, value of special electrodiagnostic tests and of supplementary modern imaging techniques, and finally, the surgical approach in case of a diagnosed entrapment of these nerves are described. Each one needs knowledge about which differential-diagnostic aspect has to be taken into account, and which diagnostic tool – electrodiagnosis and/or imaging – has to be used, particularly if there are doubts about whether there could be etiology other than by a simple entrapment. The astonishing value of high resolution ultrasound and several MRI techniques is outlined in these cases. Their value is demonstrated in many figures. Particular attention is repeatedly focussed on the Parsonage-Turner syndrome which may involve special nerve fibers within the brachial plexus and long segments of peripheral nerve trunks. Not only the muscles of the shoulder girdle such as the serratus anterior or deltoid muscles are affected by this inflammatory disease but also e.g. muscles supplied by the interosseus anterior or interosseus posterior nerves. It is argued that diagnosis has to be assessed before worthwhile surgery is started.
Finally, however, surgical instructions are added as figures in order to give an optimal idea of nerve release procedures in uncommon compression cases.
High resolution ultrasound provides important additional information on the entire aspect of varying occurrences of focal neuropathies, e.g. nerve abnormalities, irritating structures, entrapment dependent on functional limb positions, different intraneural tissue reactions, extra- or intraneural space-occupying lesions, intramuscular reactions, and differential-diagnostically important inflammatory diseases. Continuous examination of the entire nerve is possible as well as its dynamic assessment during active and passive limb or muscle movement. There are no side effects and no contraindications. Children can be examined pain free. The method is more and more easily available and less cost- and time- consuming than MRI. Limitations only result from deeply situated nerves, obese patients and the phenomenon of acoustic shadowing; osteosynthesis material, hematoma and scar tissue formation can hide small nerve structures from detection. Furthermore, not to be neglected, the method depends on the learn curve and the final experience of the examiner. On the other hand, magnetic resonance neurography also provides some important additional information for assessing the diagnosis and differential diagnosis of focal neuropathies. Especially deep situated structures of the peripheral nervous system such as the lumbosacral plexus and the intrapelvic part of the sciatic nerve can be examined with greater accuracy than in high resolution ultrasound. We cover high contrast resolution and the capacity to administer contrast agents. However, MRN is not applicable in obese patients and in patients with a pacemaker or cardiac defibrillator, and is also difficult to apply when dealing with children. The method is not available everywhere and is cost- and time-consuming.
"Drop foot" palsy attributed to the prolonged and repetitive maintenance of the crossed-leg posture has been occasionally reported. We report, to the best of our knowledge, the first case of magnetic resonance imaging evidence of peroneal nerve abnormalities related to right drop-foot palsy in a tall healthy subject with habit of prolonged daily leg crossing.
MR imaging of peripheral nerves has been described in relation to abnormalities such as nerve injury, entrapment, and neoplasm. Neuroma formation is a known response to peripheral nerve injury, and here we correlate the MRN appearance of postinjury neuroma formation with intraoperative findings. We also present the MR imaging features of surgical treatment with a synthetic nerve tube and nerve wrap on postoperative follow-up imaging.
Radial nerve compression by a ganglion in the radial tunnel is not common. Compressive neuropathies of the radial nerve in the radial tunnel can occur anywhere along the course of the nerve and may lead to various clinical manifestations, depending on which branch is involved. We present two unusual cases of ganglions located in the radial tunnel and requiring surgical excision.
A 31-year-old woman complained of difficulty in fully extending her fingers at the metacarpophalangeal joint for 2 weeks. Before her first visit, she had noticed a swelling and pain in her right elbow over the anterolateral forearm. The extension muscle power of the metacarpophalangeal joints at the fingers and the interphalangeal joint at the thumb had decreased. Sonography and magnetic resonance imaging of the elbow revealed a cystic lesion located at the area of the arcade of Frohse. A thin-walled ovoid cyst was found against the posterior interosseous nerve during surgical excision. Pathological examination was compatible with a ganglion cyst. The second case involved a 36-year-old woman complaining of numbness over the radial aspect of her hand and wrist, but without swelling or tumor in this area. The patient had slightly decreased sensitivity in the distribution of the sensory branch of the radial nerve. There was no muscle weakness on extension of the fingers and wrist. Surgical exposure defined a ganglion cyst in the shoulder of the division of the radial nerve into its superficial sensory and posterior interosseous components. There has been no disease recurrence after following both patients for 2 years.
Compression of nerves by extraneural soft tissue tumors of the extremities should be considered when a patient presents with progressive weakness or sensory changes in an extremity. Surgical excision should be promptly performed to ensure optimal recovery from the nerve palsy.
Magnetic resonance imaging (MRI) was used to evaluate 22 histologically proven peripheral nerve sheath tumors, approximately two-thirds of which arose in the lower extremity. The histologic distribution was as follows: 12 schwannomas, 7 neurofibromas, and 3 malignant peripheral nerve sheath tumors (2 of which occurred in patients with neurofibromatosis). Most lesions demonstrated an intermediate to moderately bright signal on T1-weighted images and were minimally inhomogeneous. All lesions were moderately bright on proton-density-weighted images and bright on T2-weighted images, again with variable inhomogeneity. The extent of the tumor was best assessed on proton-density- and T2-weighted images. Smooth margins were noted in 19 lesions. Of the 3 remaining lesions, 2 were malignant (but had been subjected to biopsy prior to MRI), and the other lesion was a plexiform neurofibroma. MRI accurately determined the relationship between the lesion and the adjacent neurovascular structures and muscles, thereby assisting surgical management. On MRI, 5 lesions demonstrated coexistent subtle muscle atrophy along the longitudinal axis of surrounding or distally innervated musculature. This latter finding, together with the presence of a tumor in the vicinity of a large nerve trunk, suggests a peripheral nerve sheath neoplasm.
Overuse syndromes of the upper extremity in the athletic population are a common and often difficult problem for physician and patient alike. Optimal function of the upper extremity is tied intimately to success in many sporting activities. Correct diagnosis and proper care require a thorough knowledge of the pertinent anatomy, pathophysiology, and pathomechanics involved in each disorder. Conservative care with rest, activity modification, and medication is adequate for most athletic injuries. Surgical intervention may be indicated for continuing pain, decreased performance, or to prevent chronic changes. Surgery must be followed by thoughtfully prepared training and rehabilitation programs to optimize the chances of a successful outcome.
Intermittent compression of the PIN within and just distal to the anatomic region known as the radial tunnel is responsible for a constellation of signs and symptoms known as radial tunnel syndrome. The five structures commonly implicated as possible offenders include the fibrous adhesions between the brachialis and brachioradialis, the leash of Henry, the fibrous edge of the ECRB, the arcade of Fröhse, and fibrous bands associated with the supinator muscle. The condition is dominated by pain centered over the radial tunnel, whereas muscle weakness, if present, is clinically insignificant. Specific attention to the character and point of maximal tenderness, worsening of pain on the provocative middle finger extension and resisted supination tests, and relief of symptoms following a radial tunnel anesthetic block help diagnose RTS. Electrodiagnostic testing presently has limited use in diagnosing RTS. The management of RTS includes activity modification and other conservative measures. Most patients, however, eventually require surgery, in which routine release of all potential constricting structures is performed. Although several surgical approaches are available, the brachioradialis–ERCL interval approach is one that has been very satisfying in our hands.
MRI has been used for almost two decades for the evaluation of peripheral nerve disorders. This article highlights the relative advantages and disadvantages of 3T MR neurography in the evaluation of peripheral neuropathies. The authors also describe the high-resolution MR neurography technique on 3T MRI, along with the approach to its interpretation that has evolved at one institution.
Magnetic resonance (MR) imaging has become the method of choice for evaluating patients with brachial plexopathy. The multiplanar capability of MR imaging and its superior ability to differentiate nerves from vessels and surrounding soft tissues contribute to its success. The article describes the MR anatomy of the brachial plexus in the axial, coronal, and sagittal planes and reviews the MR characteristics of traumatic and nontraumatic etiologies of brachial plexopathy.
This study was designed to determine the cause of upper trunk brachial plexopathy, which is referred to as a "stinger" or a "burner." This injury often has been thought to occur secondary to traction when an athlete sustains a lateral flexion injury of the neck. At the United States Military Academy, a 4-phase study was begun with 261 tackle football players (236 intramural- and 25 varsity-level players) to investigate this injury. Electro myography and nerve root stimulation studies were used to delineate the lesion, which was found in a total of 32 players who continued throughout the study. This study demonstrated that a much more common mech anism of injury resulting in the stinger syndrome is probably compression of the fixed brachial plexus be tween the shoulder pad and the superior medial scapula when the pad is pushed into the area of Erb's point, where the brachial plexus is most superficial. An or thosis was designed to protect the brachial plexus from the compressive force of the shoulder pad. In prelimi nary trials, this orthosis had been very effective in decreasing the number of episodes in which stinger injuries occurred.
Multiple neurilemomas in diverse locations of the body developed in a 53-year-old woman. The patient had multiple neurilemomas which occurred in the thoracic spine, lumbar spine, retroperitoneal sympathetic chain, sacral nerve root, femoral nerve, both sciatic nerves, radial nerve, and ulnar nerve without evidence of Von Recklinghausen's disease. This is the first well documented report on multiple neurilemomas with whole body distribution.
(C) 1998 Lippincott Williams & Wilkins, Inc.
Peripheral nerve amyloidosis is the cardinal feature of familial amyloid polyneuropathy (FAP) but can also be seen in primary light chain (AL) amyloidosis and dialysis (β2-microglobulin) related amyloidosis. The generalized neuropathy seen in all forms of peripheral nerve amyloidosis is similar, characterized by a severe progressive mixed neuropathy with autonomic dysfunction. Pathologically, amyloid is found in the peripheral nervous system as amorphous, eosinophilic, extracellular deposits. FAP is most commonly associated with variant plasma transthyretin (TTR), although it has also been described in association with mutant apolipoprotein A-1 and gelsolin. There are now at least 36 point mutations in the TTR gene associated with FAP and these continue to be described. Recent studies on the possible role individual point mutations in the TTR gene may play in amyloidosis have helped give us an insight into the mechanisms behind peripheral nerve amyloidosis. This article reviews the clinical and pathological features of the peripheral nerve amyloidosis and discusses theories of amyloidogenesis based on studies of FAP.
In two patients a peripheral neuropathy was the presenting symptom of a noncutaneous peripheral T-cell lymphoma. In the first patient, the neuropathy had a relapsing and remitting course, the symptoms improved under corticosteroid therapy. The second patient suffered from a relentless neuropathy. In both cases the lymphoma infiltrated the peroneal nerve with an angiocentric and perivascular pattern resembling that observed in central nervous system lymphomas. The characterization of T-cell subsets in the lymph node showed cells with the helper/inducer and suppressor/cytotoxic phenotype in the first case and a predominance of cells with the helper/inducer phenotype in the second case. In the nerve, lymphocytes beared the helper/inducer phenotype antigen. A typical paraneoplastic vasculitis of nerve showed clearly different immunologic features.
Although radial nerve palsy associated with a closed humeral shaft fracture may be managed by observation, it is our experience that an open humeral shaft fracture with radial nerve palsy requires exploration of the nerve. In a series of 14 patients with radial nerve palsy caused by an open humeral shaft fracture, 9 (64%) of the 14 patients had a radial nerve that was either lacerated or interposed between the fracture fragments. There was an equal incidence of radial nerve lacerations or entrapments in types I, II, and III open humeral shaft fractures. Epineural radial nerve repair, done primarily or secondarily, provided a satisfactory return of radial nerve function. Rigid fixation of the associated fracture is the recommended treatment.
Methods were invented that made it possible to image peripheral nerves in the body and to image neural tracts in the brain. The history, physical basis, and dyadic tensor concept underlying the methods are reviewed. Over a 15-year period, these techniques-magnetic resonance neurography (MRN) and diffusion tensor imaging-were deployed in the clinical and research community in more than 2500 published research reports and applied to approximately 50,000 patients. Within this group, approximately 5000 patients having MRN were carefully tracked on a prospective basis.
A uniform Neurography imaging methodology was applied in the study group, and all images were reviewed and registered by referral source, clinical indication, efficacy of imaging, and quality. Various classes of image findings were identified and subjected to a variety of small targeted prospective outcome studies. Those findings demonstrated to be clinically significant were then tracked in the larger clinical volume data set.
MRN demonstrates mechanical distortion of nerves, hyperintensity consistent with nerve irritation, nerve swelling, discontinuity, relations of nerves to masses, and image features revealing distortion of nerves at entrapment points. These findings are often clinically relevant and warrant full consideration in the diagnostic process. They result in specific pathological diagnoses that are comparable to electrodiagnostic testing in clinical efficacy. A review of clinical outcome studies with diffusion tensor imaging also shows convincing utility.
MRN and diffusion tensor imaging neural tract imaging have been validated as indispensable clinical diagnostic methods that provide reliable anatomic pathological information. There is no alternative diagnostic method in many situations. With the elapsing of 15 years, tens of thousands of imaging studies, and thousands of publications, these methods should no longer be considered experimental.
Magnetic resonance (MR) imaging findings in three patients with acute onset of neuritic shoulder pain and weakness included high signal intensity in supra- and infraspinatus muscles (n = 2), partial involvement of infraspinatus muscle (n = 1) and of deltoid muscle (n = 1), and atrophy of supra- and infraspinatus muscles (n = 2). Clinical diagnosis of acute brachial neuritis (Parsonage-Turner syndrome) correlated with MR imaging results in all cases.
Three-dimensional (3D) diffusion-weighted reversed fast imaging with steady state precession (3D DW-PSIF) MR sequence has the potential to create nerve-specific images. The authors describe the technical issues and their initial experience with this imaging technique employed for peripheral MR neurography.
Irreparable peripheral nerve palsies rarely present as neurological complications in infectious mononucleosis. A case of isolated proximal radial nerve palsy resulting from an acute infection with Epstein-Barr virus is reported. The hand function was restored by multiple tendon transfer surgery.
High-resolution MR imaging of peripheral nerves is becoming more common and practical with the increasing availability of 3T magnets. There are multiple reports of MR imaging of peripheral nerves in compression and entrapment neuropathies. However, there is a relative paucity of literature on MRN appearance of diffuse peripheral nerve lesions. We attempted to highlight the salient imaging features of myriad diffuse peripheral nerve disorders and imaging techniques for MRN. Using clinical and pathologically proved relevant examples, we present the MRN appearance of various types of diffuse peripheral nerve lesions, such as traumatic, inflammatory, infectious, hereditary, radiation-induced, neoplastic, and tumor variants.
The peripheral nerves of the upper limb are affected by a number of entrapment and compression neuropathies. These discrete syndromes involve the brachial plexus as well as the musculocutaneous, axillary, suprascapular, ulnar, radial, and median nerves. Clinical examination and electrophysiologic studies are the traditional mainstay of diagnostic work-up; however, ultrasonography and magnetic resonance imaging provide spatial information regarding the affected nerve and its surroundings, often assisting in narrowing the differential diagnosis and guiding treatment. Imaging is particularly valuable in complex cases with discrepant nerve function test results. Familiarity with the clinical features of various peripheral neuropathies of the upper extremity, the relevant anatomy, and the most common sites and causes of nerve entrapment assists in diagnosis and treatment.
The objective of this study was to identify the MRI criteria that best differentiate malignant peripheral nerve sheath tumors from benign neurofibromas.
We retrospectively analyzed MR images obtained for 41 histologically diagnosed cases of malignant peripheral nerve sheath tumor and 20 cases of neurofibroma that had been treated at four tertiary institutions. Twenty of the patients with malignant peripheral nerve sheath tumors and 14 patients with neurofibromas developed the disease in association with neurofibromatosis 1. The MR images were evaluated with regard to tumor size, signal intensity, heterogeneity of T1- and T2-weighted MR images, enhancement pattern, definition of margins, presence of perilesional edemalike zone, and presence of intratumoral cystic lesions.
Significant differences between malignant peripheral nerve sheath tumors and neurofibromas were noted for the largest dimension of the mass, peripheral enhancement pattern, perilesional edemalike zone, and intratumoral cystic lesion. In cases associated with neurofibromatosis 1, heterogenicity on T1-weighted images was also significant in differentiating neurofibroma from malignant peripheral nerve sheath tumor. The presence of two or more of the four features suggestive of malignancy indicated malignant peripheral nerve sheath tumor with a sensitivity of 61% and a specificity of 90%.
The MR features described in this study are useful for distinguishing malignant peripheral nerve sheath tumors from neurofibromas. If a tumor has two or more of the four statistically significant features, it can be considered to be highly suspicious of malignancy and should be subjected to a biopsy for early diagnosis.
Peripheral neuropathy in primary (AL) amyloidosis is usually lower-limb predominant, length-dependent, symmetrical, and affects small (pain and autonomic) fibers, as much or more than large fibers. We report a patient with stepwise progressive, multiple upper limb mononeuropathies that were due to nerve biopsy-proven primary amyloidosis (lambda light chain), with no systemic or autonomic features. Recognition that light chain amyloidosis may be the cause of a multiple mononeuropathy pattern adds to the differential diagnosis of this clinical phenotype.
Magnetic resonance imaging (MRI) of the brachial plexus is the imaging modality of first choice for depicting anatomy and pathology of the brachial plexus. The anatomy of the roots, trunks, divisions and cords is very well depicted due to the inherent contrast differences between the nerves and the surrounding fat. In this pictorial review the technique and the anatomy will be discussed. The following pathology will be addressed: neurogenic tumors of the brachial plexus and sympathetic chain, superior sulcus tumors, other tumors in the vicinity of the brachial plexus, the differentiation between radiation and metastatic plexopathy, trauma, neurogenic thoracic outlet syndrome and immune-mediated neuropathies.
The risk of focal compression neuropathy in the setting of an underlying inflammatory polyneuropathy is unknown. A man developed ascending weakness and severe sensory ataxia and could not walk. Electromyography was diagnostic of Guillain-Barré syndrome. He improved with gammaglobulin and was released home 1 month later. Shortly after discharge, he developed severe left arm pain followed by wrist and finger drop. He was readmitted for another round of gamma-globulin without improvement. Subsequent electromyography showed severe radial neuropathy. Only then did he disclose that he usually slept with his wife's head on his arm at home. Two years later, he had recovered from Guillain-Barré syndrome with minimal gait imbalance, but wrist and finger extension remained weak. Reduced awareness of warning paresthesias coupled with the underlying polyneuropathy may account for this case of severe radial nerve compression. Potential mechanisms underlying increased nerve susceptibility to compression in the setting of polyneuropathy are reviewed.
A 34-year-old man presented with 1 year's duration of right-sided finger extension weakness, with mild sensory symptoms over the dorsum of the hand on exercising the right hand. There was a history of pain over the lateral aspect of the right elbow on playing tennis. On clinical examination, there was weakness of the finger extensors, with mild involvement of the wrist extensors. Muscle power testing of the brachioradialis and triceps were within normal limits. There were no associated sensory deficits, and tendon reflexes were normal. The possibility of right posterior interosseous nerve palsy was considered.
This report deals with the advantages and disadvantages associated with the most commonly used methods of stabilization after a pathologic fracture of the humerus shaft.
A total of 39 patients with 41 metastatic lesions and pathologic fractures of the humerus, treated surgically between 1992 and 2007, were retrospectively analyzed.
The rate of local complications was 14.6% (6 of 41). Radial nerve injury was the only local complication and was exclusively observed in patients who underwent open reduction and plate fixation. The overall rate of osteosynthesis failure was 12.2% (5 of 41). Two failures were observed in 21 patients with open reductions and plate fixations, compared with three failures in 20 procedures involving closed reductions and intramedullary stabilization. The 1- and 2-year survival rates were 0.35 and 0.2 in ORIF and 0.07 and 0 in patients with IM fixation retrospectively.
Intramedullary stabilization is a reliable method for fixation of pathologic fractures of the humerus diaphysis for patients in the advanced stage of metastatic disease. ORIF are preferable to IM fixations for the treatment of metaphyseal fractures and for those patients with a solitary metastasis in the humerus or those with a better prognosis.
The purpose of this study was to find out whether high-resolution sonography can be used to examine the superficial radial nerve. The sonographic appearance of the superficial radial nerve was assessed in 20 control subjects and the cross-sectional area could be measured in all subjects. The mean cross-sectional area of the superficial radial nerve in the control subjects was 2 mm(2) (SD 0.5 mm(2), range 1-3 mm(2)). Moreover, two patients with a superficial radial neuropathy and abnormal high-resolution sonography are reported. One patient had an enlarged nerve after trauma, which was probably a neuroma. The other patient had a histologically proven Schwannoma of the superficial radial nerve. The superficial radial nerve, although small in size, can be visualized by high-resolution sonography using specific landmarks. High-resolution sonography can be useful to assess the underlying cause of superficial radial nerve pathology.
A malignant lymphoma of the reticulum cell sarcoma variety developed in the right radial nerve of a 60-year-old man 3 years after he had presented with a primary malignant lymphoma of the brain. Serial evaluations and metastatic workups over several years failed to demonstrate evidence of extraneural metastasis.
1. The arcade of Frohse, a fibrous arch over the posterior interosseous nerve, may well play a part in causing progressive paralysis of the posterior interosseous nerve, both with and without injury.
2. Paralysis of the muscles supplied by this nerve with no evidence of recovery after six weeks, either electromyographic or clinical, should be treated by exploration and splitting of the arcade of Frohse.
1. Three cases of paralysis of the radial nerve after intensive muscular effort in extension of the elbow are described. Clinical and electrophysiological evidence is recorded.
2. There was motor and sensory affection of varying degree and extent in the distribution of the radial nerve.
3. The type of lesion in each case was that of neurapraxia, and rapid spontaneous recovery occurred in each case.
4. The level of the lesion was in the arm, below the origin of the branches to the triceps.
5. The cause of the lesion was thought to be compression by a fibrous arch related to the lateral head of the triceps.
6. The cases are discussed in relation to other instances of compression of nerves by fibrous arches, and an explanation is advanced for spontaneous recovery.
Results of management of 57 patients with sarcoma of soft tissue on an extremity by radical dose radiation therapy are presented. These patients had been treated 2 to 10 years previously at the University of Texas M.D. Anderson Hospital. Forty-six patients were seen after simple excision (no palpable tumor at time of our examination), while 11 patients were treated for the primary or a recurrent tumor. The recommended surgical treatment was amputation in all patients of this study sample. Radiation therapy technique was complex; dose level was 6300–7000 rads or the equivalent in 61/2-7 weeks. Local control has been achieved in 50 of 57 patients. For the 46 patients with lesions in the elbow-hand or knee-foot regions, local control has been 100%. In contrast, 7 of 11 tumors located in the proximal extremities (upper arm or thigh) have recurred locally. A useful limb has been retained for 2 to 10 years in 34 of the cases. The more refined techniques of therapy now being employed yield a good functional result in nearly all cases. Metastasis-free survival at 2 to 10 years is 58%. This figure depends not only upon histologic type but apparently also on histologic grade: 26 of 36 (72%) for Grades 1 and 2 but only 7 of 17 (41%) for Grade 3.
This study was designed to determine the cause of upper trunk brachial plexopathy, which is referred to as a "stinger" or a "burner." This injury often has been thought to occur secondary to traction when an athlete sustains a lateral flexion injury of the neck. At the United States Military Academy, a 4-phase study was begun with 261 tackle football players (236 intramural- and 25 varsity-level players) to investigate this injury. Electromyography and nerve root stimulation studies were used to delineate the lesion, which was found in a total of 32 players who continued throughout the study. This study demonstrated that a much more common mechanism of injury resulting in the stinger syndrome is probably compression of the fixed brachial plexus between the shoulder pad and the superior medial scapula when the pad is pushed into the area of Erb's point, where the brachial plexus is most superficial. An orthosis was designed to protect the brachial plexus from the compressive force of the shoulder pad. In preliminary trials, this orthosis had been very effective in decreasing the number of episodes in which stinger injuries occurred.
Magnetic resonance (MR) imaging has become the method of choice for evaluating patients with brachial plexopathy. The multiplanar capability of MR imaging and its superior ability to differentiate nerves from vessels and surrounding soft tissues contribute to its success. The article describes the MR anatomy of the brachial plexus in the axial, coronal, and sagittal planes and reviews the MR characteristics of traumatic and nontraumatic etiologies of brachial plexopathy.
The purpose was to assess the incidence and clinical manifestations of radiation-induced brachial plexopathy in breast cancer patients, treated according to the Danish Breast Cancer Cooperative Group protocols.
One hundred and sixty-one recurrence-free breast cancer patients were examined for radiation-induced brachial plexopathy after a median follow-up period of 50 months (13-99 months). After total mastectomy and axillary node sampling, high-risk patients were randomized to adjuvant therapy. One hundred twenty-eight patients were treated with postoperative radiotherapy with 50 Gy in 25 daily fractions over 5 weeks. In addition, 82 of these patients received cytotoxic therapy (cyclophosphamide, methotrexate, and 5-fluorouracil) and 46 received tamoxifen.
Five percent and 9% of the patients receiving radiotherapy had disabling and mild radiation-induced brachial plexopathy, respectively. Radiation-induced brachial plexopathy was more frequent in patients receiving cytotoxic therapy (p = 0.04) and in younger patients (p = 0.04). The clinical manifestations were paraesthesia (100%), hypaesthesia (74%), weakness (58%), decreased muscle stretch reflexes (47%), and pain (47%).
The brachial plexus is more vulnerable to large fraction size. Fractions of 2 Gy or less are advisable. Cytotoxic therapy adds to the damaging effect of radiotherapy. Peripheral nerves in younger patients seems more vulnerable. Radiation-induced brachial plexopathy occurs mainly as diffuse damage to the brachial plexus.
Intermittent compression of the PIN within and just distal to the anatomic region known as the radial tunnel is responsible for a constellation of signs and symptoms known as radial tunnel syndrome. The five structures commonly implicated as possible offenders include the fibrous adhesions between the brachialis and brachioradialis, the leash of Henry, the fibrous edge of the ECRB, the arcade of Fröhse, and fibrous bands associated with the supinator muscle. The condition is dominated by pain centered over the radial tunnel, whereas muscle weakness, if present, is clinically insignificant. Specific attention to the character and point of maximal tenderness, worsening of pain on the provocative middle finger extension and resisted supination tests, and relief of symptoms following a radial tunnel anesthetic block help diagnose RTS. Electrodiagnostic testing presently has limited use in diagnosing RTS. The management of RTS includes activity modification and other conservative measures. Most patients, however, eventually require surgery, in which routine release of all potential constricting structures is performed. Although several surgical approaches are available, the brachioradialis-ERCL interval approach is one that has been very satisfying in our hands.
We present a case of multiple schwannomas in the radial nerve. The occurrence of multiple schwannomas in a single major nerve is very rare. Magnetic resonance imaging was useful in detecting the tumours. As schwannomas may be multiple without clinical symptoms, we recommend MR imaging of the entire limb when schwannomas occur in a major nerve in the upper extremity.
Multiple neurilemomas in diverse locations of the body developed in a 53-year-old woman. The patient had multiple neurilemomas which occurred in the thoracic spine, lumbar spine, retroperitoneal sympathetic chain, sacral nerve root, femoral nerve, both sciatic nerves, radial nerve, and ulnar nerve without evidence of Von Recklinghausen's disease. This is the first well documented report on multiple neurilemomas with whole body distribution.
To distinguish between benign and malignant tumors in the peripheral nerves.
The clinical, imaging and histologic findings of 99 benign and 16 malignant tumors in the peripheral nerves were reviewed retrospectively.
Preoperative motor weakness was observed in only six of 99 benign tumors and was mild, while slight to severe motor weakness was present in 15 of 16 malignant lesions. Pain at rest was present in five of 99 benign tumors and in 15 of 16 malignant tumors. All benign lesions showed a smooth tumoral margin, while half the malignant lesions showed an invasive margin on CT or MRI. Thirteen of 28 benign lesions on CT and nine of 23 on MRI showed round to geographic central enhancement, but this pattern was not seen in malignant lesions.
Absence of severe motor weakness and a central enhancement pattern strongly suggest a benign nature, while severe rest pain and invasive tumor margin suggest malignant lesions in peripheral nerve tumors.
Lymphoma presenting as a solitary tumor of peripheral nerve is exceedingly rare, with only six previously reported cases. The authors describe an additional four cases of primary lymphoma of peripheral nerve involving the sciatic nerve (two cases), the radial nerve, and the sympathetic chain and spinal nerve. The patients were two men and two women with an average age of 55.5 years. All tumors were high-grade B-cell lymphomas. Two patients experienced relapse of disease with involvement of other nervous system sites and died of lymphoma. One patient is alive with stable local disease at 57 months. The fourth patient is alive with no evidence of disease at 54 months. Expression of neural cell adhesion molecule (CD56) has been reported to correlate with an increased incidence of central nervous system involvement in peripheral T-cell lymphoma; all their cases were CD56 negative. Recent reports indicate a high proportion of primary brain lymphomas show loss of CDKN2A/p16 gene expression. Therefore, CDKN2A/p16 was evaluated in their patients both by polymerase chain reaction and by immunohistochemistry for the p16 protein. The authors found homozygous deletion of the CDKN2A/p16 gene in one of three patients studied, confirmed immunohistochemically by absent staining for p16. The fourth patient showed absent staining for p16, suggesting inactivation of the gene in this case as well. The two patients with p16 loss both died of lymphoma, whereas the two patients with normal p16 expression are alive. Primary lymphoma of peripheral nerve is a rare neoplasm, usually of large B-cell type, has a variable prognosis, and appears to have less consistent loss of p16 expression than primary central nervous system lymphoma.
We describe a case of chronic distal sensorimotor neuropathy associated with neurofibromatosis type 1 (NF1) in a 15-year old girl. The patient showed a striking clinical picture consisting of diffuse nodular enlargements of peripheral nerves. Motor conduction velocities were decreased and sensory responses were absent after maximal stimulation. Magnetic resonance imaging (MRI) was performed throughout the body and disclosed generalized nerve sheath neurofibromas affecting all peripheral nerves. Intracranially, the patient had a glioma of the left optic nerve, but no other cranial nerve involvement. These results demonstrate the value of MRI for visualization of the peripheral nervous system in neurofibromatosis.
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.
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.
To determine the long-term effects of radiotherapy (RT) in children treated for extremity sarcoma.
Between 1964 and 1997, 15 of 33 children treated with RT for extremity sarcomas at the University of Iowa have survived with a median follow-up was 20 years (range, 6-36 years). There were 10 boys and 5 girls with a median age of 13 years (range, 3.5-20 years) at the time of irradiation. The diagnosis was Ewing's sarcoma in 8 (53%), synovial sarcoma in 4 (27%), alveolar rhabdomyosarcoma in 2, and fibrosarcoma in 1. Location of primary tumor was lower extremity in 10 (67%) and upper extremity in 5 (33%). RT was given as the definitive therapy for 9 children (median dose, 55.8 Gy; range, 45-66 Gy) and as an adjuvant postoperative treatment in 6 (median, 63 Gy; range, 41.4-66.4 Gy). (60)Co was used in 6 (40%), 4 mV in 4, 6 mV in 2, and 250 kV photons in 2 patients; 1 child was treated with a combination of 12 and 15 MeV electrons for a Ewing's sarcoma of the distal femur. Another child had a 25 Gy intraoperative RT boost after 41.4 Gy conventional RT. Late effects to the muscle, soft tissue, and growing bone were assessed using the objective portion of the LENT-SOMA scale proposed by the Late Effects Consensus Conference.
Late effects were seen in all patients and included atrophy in 12 (80%), fibrosis in 12 (80%), bone growth abnormalities in 10 (67%), impairment of mobility and extremity function in 6 (40%), edema in 3 (20%), and peripheral nerve injury in 2 (13%). Ten of 15 (67%) children had Grade 1 or 2 growing bone, muscle, soft tissue, or peripheral nerve complications. Two patients (13%) had a Grade 3 mobility and extremity function score and had moderate to severe limitation of movement. Two children (13%) required epiphysiodesis because of a shorter treated leg. The patient who received an intraoperative RT boost of 25 Gy developed sensory dysfunction of the ulnar nerve 11 years after RT. Another developed radial nerve palsy 3 years after marginal resection and postoperative RT and required tendon transfer repair. One patient had radiation-induced vasculitis with popliteal artery thrombosis 23 years after RT. Five (33%) developed a fracture of the irradiated bone at a median time of 8 years after RT (range: 9 months to 22.2 years); all had Ewing's sarcoma, and 3 of these patients were subsequently found to have a secondary bone cancer (osteosarcoma 2, malignant fibrous histiocytoma 1) in the RT field. One of these patients also developed breast cancer 26 years after lung RT for metastatic Ewing's sarcoma. Overall, 11 surgical procedures in 8 children were performed to correct a limb preservation treatment toxicity.
Although most children treated with RT for a pediatric extremity sarcoma have minimal late toxicity by LENT-SOMA scale, approximately half required a surgical procedure to correct a late effect. A fracture in the irradiated bone may be the presenting sign or may precede a radiation-induced bone malignancy, as seen in 3 of the patients in this study.
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.
Occult interosseous ganglions in the proximal forearm can result in pain and decreased supination. We will describe the magnetic resonance imaging (MRI) diagnosis of an interesting case of supinator atrophy secondary to compression of the posterior interosseous branch of the radial nerve. A brief review of this entity follows.