Post-traumatic shoulder 'dystonia': persistent abnormal postures of the shoulder after minor trauma

Peripheral trauma induced dystonia or post-traumatic syndrome?

The relationship between peripheral trauma and dystonia has been debated for more than a century but the issue still remains controversial. There are passionate supporters and detractors of the association and both the groups have their own arguments. This review aims to critically evaluate those arguments and presents current understanding of this association. In the process, the relevant case series and scientific papers exploring this subject have been discussed. Upon careful review of available literature coupled with their own experience, the authors believe that peripheral trauma can predispose to abnormal posturing of a body part after variable intervals. To call this posturing a "post-traumatic dystonia" might be premature and the term "post-traumatic syndrome" can be used instead. More work is needed to unravel the pathophysiology of this post-traumatic syndrome.

Unusual focal dyskinesias

This chapter reviews focal dyskinesias that affect a restricted region of the body in isolation. Focal dyskinesias often affect body parts not commonly involved in isolation by movement disorders and are not readily classified into one of the major categories of movement disorders or peripheral nerve excitability syndromes. The clinical features and phenomenology of these "unusual focal dyskinesias" are discussed according to the region affected (ear, lip, chin, jaw, tongue, abdomen, and diaphragm (belly dancer's dyskinesias), back, scapula, and limbs). The phenomenology and origin of the unusual focal dyskinesias remain the subject of debate. Most are characterized by slow semirhythmic jerky movements at variable (usually slow) frequencies superimposed on sustained postures, consistent with dystonic movements. However, the body parts affected and pattern of occurrence (in repose rather than during action) are different to those usually seen in primary dystonia. Many of the unusual focal dyskinesias are associated with trauma and pain to the affected region, prompting the suggestion that the movements follow central sensorimotor reorganization occurring spontaneously or secondary to changes in the peripheral nervous system. In other cases, inconsistent signs and spontaneous recovery suggest a psychogenic origin.

Focal hand dystonia in a patient with ulnar nerve neuropathy at the elbow

We describe a patient who presented with dystonia of her small finger secondary to entrapment neuropathy of the ulnar nerve at the elbow. Pre operative electrophysiological studies suggested that the locus of entrapment was located proximal to the medial epicondyle. This was confirmed intraoperatively by the presence of a thickened and prominent arcade of Struthers. Surgical decompression resulted in a rapid and dramatic improvement of the dystonic pattern as well as an improvement in nerve conduction. A review of literature has not revealed any other reports of such a clear cut association between ulnar nerve entrapment and non task-specific focal hand dystonia.

Peripherally induced movement disorders

Peripherally induced movement disorders may be defined as involuntary or abnormal movements triggered by trauma to the cranial or peripheral nerves or roots. Although patients often recall some history of trauma before the onset of a movement disorder, determining the true relationship of the disorder to the earlier trauma is often difficult. The pathophysiology of these disorders is reviewed.

[Post-traumatic focal fixed dystonia of the shoulder: a distinctive syndrome with speculative mechanisms?]

INTRODUCTION

Whether post-traumatic focal fixed dystonia has a physiological or psychologically-mediated mechanism is discussed.

CASE REPORT

We report the case of an active 22-year-old soldier with shoulder-fixed dystonia, eight months after a fall with minor right-acromioclavicular sprain.

CONCLUSION

Psychiatric examination and search of complex regional pain syndrome, radicular or accessory nerve damage, and genetic predisposition to dystonia are necessary for selecting a difficult treatment in these patients.

Cervical dystonia induced by cervical spine surgery: a case report

STUDY DESIGN

A case report.

OBJECTIVES

To describe an interesting patient who underwent a three-level corpectomy of the cervical spine complicated by cervical dystonia and eventually treated successfully with botulinum toxin injections.

SUMMARY OF BACKGROUND DATA

Cervical dystonia is a relatively rare disease and unfamiliar to many clinicians. Various types of peripheral trauma or peripheral lesion have been reported to induce cervical dystonia. However, to the best of our knowledge, there have been no reports about cervical dystonia following cervical spine surgery.

METHODS

We present a case of a 45-year-old man who developed severe axial neck pain after cervical anterior corpectomy and fibula strut grafting due to cervical myelopathy. His neck pain gradually worsened, and involuntary spasmodic neck movement developed 6 weeks after operation when his halo-vest was removed. Initially, we considered his complaint to be transient or psychogenic, and diagnosis of cervical dystonia was delayed until 14 weeks after operation.

RESULTS

Pharmacologic treatment was unsuccessful, but he was successfully treated with local intramuscular injections of botulinum toxin.

CONCLUSIONS

It must be kept in mind that cervical spine surgery is not an exceptional precipitator of cervical dystonia, despite the fact that it is extremely rare.

Persistent abnormal shoulder elevation after accessory nerve injury and differential diagnosis with post-traumatic focal shoulder-elevation dystonia: report of a case and literature review

We report on a patient with persistent abnormal shoulder posture associated with isolated neurogenic hypertrophy of the trapezius muscle due to accessory nerve injury. The patient complained of marked difficulty in shoulder elevation and abduction. Over 6-month treatment with botulinum toxin, there was a complete resolution.

A possible etiology of the internal derangement of the temporomandibular joint based on the MRI observations of the lateral pterygoid muscle

The purpose of this study was to evaluate the relationship of the temporomandibular joint (TMJ) internal derangement and lateral pterygoid muscle (LPM) by magnetic resonance imaging (MRI). In this study, 115 subjects with TMJ internal derangement (total 230 TMJs) and 21 subjects without clinical symptoms (total 42 TMJs) were included. TMJ disc position and LPM were evaluated using MRI. LPM attachments were categorized into two different types: type 1, where fibers of the superior head of the LPM (SLPM) were attached to the disc and fibers of the inferior head of the LPM (ILPM) were attached to condyle, and type 2, where fibers of the SLPM were attached to the disc and condyle, and fibers of the ILPM were attached to condyle. The presence of muscle atrophy and degeneration were also evaluated. LPM attachments were observed in two different parts. Disc displacements were common in the muscle attachments of both types. Type 1 muscle attachments were seen in 85.9% of all the anterior disc displacement without reduction (ADD) TMJs (total 64 TMJs). Atrophy was seen in a higher proportion (43.7%) in TMJs with ADD (28/64) than in TMJs with normal and anterior disc displacement with reduction (ADDR). Out of 74 TMJs with atrophy, 68 had type 1 muscle attachment. Four TMJs had atrophy in both superior and inferior heads of the lateral pterygoid. However, atrophy was not present only in the ILPM. It has been concluded that since the SLPM only attached to the disc in type 1, the disc may displace anteriorly very easily. Therefore, this situation will reduce the function of the SLPM. Reduced muscle function may cause muscle atrophy. The activity of the SLPM may be more reduced since the disc permanently dislocated in TMJs with ADD. Finally, spasm of the LPM causes disc displacement and atrophy and then the degeneration of the LPM may follow disc displacement.

Posttraumatic painful torticollis

The development of abnormal posturing of the neck or shoulder after local injury has been termed posttraumatic cervical dystonia (PTCD). Certain features seem to distinguish a unique subgroup of patients with this disorder from those with features more akin to typical idiopathic cervical dystonia, such as onset and maximum disability that occurs very quickly after injury, severe pain and a fixed abnormal posture. In an attempt to clarify the nature of this syndrome further, we evaluated 16 such patients (8 men, 8 women). Motor vehicle accident and work-related injuries were common precipitants, with posturing usually developing shortly after trauma, and little progression occurring after the first week. A characteristic, painful, fixed head tilt and shoulder elevation were present in all but one patient, who had a painless elevated shoulder and painful contralateral shoulder depression, as well as nondermatomal sensory loss in 14 patients. Additional abnormalities included dystonic posturing in a limb (2 patients) or jaw (1 patient), limb tremor (3 patients) and "give-way" limb weakness (8 patients). The tremor and the jaw dystonia demonstrated features suggestive of a psychogenic movement disorder, most commonly distractibility. Litigation or compensation was present in all 16 patients. Intravenous sodium amytal improved the posture, pain or both in 13 of 13 patients; in 7 of 13 the sensory deficit either markedly improved or normalized. General anesthesia demonstrated full range of motion in all 5 patients assessed. Psychological evaluations suggested that psychological conflict, stress, or both were being expressed via somatic channels in 11 of 12 tested patients. Our results suggest an important role of psychological factors in the etiology or maintenance of abnormal posture, pain and associated disability of these patients. The role of central factors triggered in psychologically vulnerable individuals after physical trauma is discussed. We propose that the disorder be referred to as "posttraumatic painful torticollis" rather than characterize it as a form of dystonia until further information on its pathogenesis is forthcoming.

Botulinum toxins in neurological disease

Botulinum toxins are among the most potent neurotoxins known to humans. In the past 25 years, botulinum toxin has emerged as both a potential weapon of bioterrorism and as a powerful therapeutic agent, with growing applications in neurological and non-neurological disease. Botulinum toxin is unique in its ability to target peripheral cholinergic neurons, preventing the release of acetylcholine through the enzymatic cleavage of proteins involved in membrane fusion, without prominent central nervous system effects. There are seven serotypes of the toxin, each with a specific activity at the molecular level. Currently, serotypes A (in two preparations) and B are available for clinical use, and have been shown to be safe and effective for the treatment of dystonia, spasticity, and other disorders in which muscle overactivity gives rise to symptoms. This review focuses on the pharmacology, electrophysiology, immunology, and application of botulinum toxin in selected neurological disorders.

MRI findings concerning the lateral pterygoid muscle in patients with symptomatic TMJ hypermobility

Clinical studies have shown a close association between temporomandibular joint hypermobility (TMJH) and temporomandibular disorders (TMD). While pathological change of the lateral pterygoid muscle (LPM) is one of the most emphasized in studies of TMD, there have been no detailed clinical reports of the LPM studies using magnetic resonance imaging (MRI) in TMJH. This study investigates structural and pathological alterations involving the LPM in patients with TMJH using MRI. A retrospective analysis was made of high-field MRI images from 98 patients with TMJH. LPMs of 143 joints were analyzed. In 110 joints (77%), hypertrophy, atrophy, and contracture were found in the superior belly and/or the inferior belly of the LPM. Pathological changes were more frequently found in the superior rather than the inferior belly of the LPM. In the cases with abnormalities in both bellies of the LPM, hypertrophy of the inferior belly was usually found combined with other changes of the SBLPM. The results of this study indicated that the pathological changes of the LPM or MRI are not infrequent in patients with symptomatic TMJH.

Focal shoulder-elevation dystonia

We describe 13 cases of isolated focal dystonia of the shoulder with dystonic elevation but without clinically obvious cervical dystonia. All had significant trapezius muscle hypertrophy and limitation of shoulder movement causing substantial morbidity. In nine, this developed in the immediate aftermath of shoulder region trauma, most often a motor vehicle accident; clinically significant head trauma was not a factor. In two other cases this developed in the context of chronic heavy labor (suggesting possible overuse) and in one other it developed concurrent with the symptoms of discogenic cervical (C6-7) radiculopathy. In the one remaining case, no precipitating factors were identified. Preexisting risk factors for dystonia, such as dopamine antagonist drug use, family history of dystonia, or prior brain injury, were not identified in these patients. Administration of medications used to treat dystonia was unsuccessful but botulinum toxin therapy was beneficial in all six treated cases.