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Painful limbs/moving extremities is a relatively rare condition characterized by aching pain in one limb and involuntary movement in the affected fingers or toes. Its pathomechanism is unknown. We report two patients with painful limbs/moving extremities. In one patient with a painful arm and moving fingers, the symptoms were resolved after surgery.
Patient 1 was a 36-year-old man with a painful arm and moving fingers. Treatment with administration of analgesics was not effective. Postmyelographic CT showed stenosis of the right C5/C6 foramen attributable to cervical spondylosis and a defect of the contrast material at the foramen. He was treated with cervical foraminotomy. Patient 2 was a 26-year-old woman with a painful leg and moving toes. The pain and involuntary movement appeared 2 weeks after discectomy at L5/S1. Lumbar MRI and myelography showed no indications of nerve root compression. She was treated with a lumbar nerve root block. The pain and involuntary movement completely disappeared in both patients after treatment.
Numerous studies report treatments for painful limbs/moving extremities, but few report successful treatment. Recently, botulinum toxin A injection and epidural spinal cord stimulation have been used and are thought to benefit this condition. Successful surgical treatment previously was reported for only one patient.
If imaging indicates compression of nerve tissue, we believe surgical decompression should be considered for patients with painful limbs/moving extremities who do not respond to nonoperative treatment.
The online version of this article (doi:10.1007/s11999-010-1437-y) contains supplementary material, which is available to authorized users.
Painful arm and moving fingers (PAMF), which is characterized by aching pain in the upper extremity and spontaneous involuntary movements of the fingers, was first reported by Verhagen et al.  in 1985. A similar and more common syndrome in the lower extremity is called painful legs and moving toes (PLMT), first coined by Spillane et al.  in 1971. Papapetropoulos and Argyriou  described these disorders as painful limbs/moving extremities (PLME). These were divided into several subtypes according to localization of movement and pain and laterality of symptoms. PLME is a relatively rare disorder and its pathomechanism is unknown.
We treated two patients with PLME. The first was a patient with PAMF in whom cervical nerve root compression potentially led to the symptoms, as indicated by improvement after cervical foraminotomy. The second was a patient with PLMT after surgery for lumbar disc herniation. We found only one previous report of patients with PAMF whose symptoms were resolved after surgery . We herein report these two patients and review the literature.
A 36-year-old man was referred to our hospital after a 1-month history of pain in his neck and right scapular region, followed by aching or burning pain in his right thumb, index finger, and upper arm and involuntary movements of the right thumb. Treatment with administration of analgesics was not effective. He and his family had no remarkable contributory history including psychogenic disease.
On examination, there was aching pain at rest in his right thumb and index finger and involuntary flexion-extension movement of the thumb at the carpometacarpal joint (Video 1, Supplemental Website Material; supplemental materials are available with the online version of CORR).
Movement of the thumb increased in proportion to the degree of pain and could not be stopped by conscious effort. Moreover, the patient could not voluntarily reproduce the movement on the unaffected side when asked to do so. It disappeared during sleep but otherwise, basically, was a continuous movement. Neurologic examinations showed Grade 4 of 5 in manual muscle testing of the right biceps muscle and wrist extensor muscles, sensory disturbance in the right C6 distribution, weakness in the right brachioradialis tendon reflex, and radiating pain to the thumb and index finger reproduced by neck extension and side flexion (positive test using the criteria of Spurling and Scoville ) on the right side, indicating right C6 radiculopathy. MRI showed no compression of the spinal cord but minimal stenosis at the right C5/C6 foramen. Also, postmyelographic CT showed stenosis of the right C5/C6 foramen attributable to cervical spondylosis and a defect of the contrast material at the foramen (Fig. 1). A right C6 nerve root block was performed and resulted in temporary disappearance of the pain. The pain recurred the next morning and the involuntary movement did not stop while the nerve block was in effect.
Right C6 cervical spondylotic radiculopathy was diagnosed on the basis of this patient’s pain. We consulted a neurologist and planned to observe the patient closely and obtain additional studies including electromyography (EMG) and brain MRI. However, because the pain was severe and resistant to oral medication or nerve root block, we proceeded with surgery for the right C6 cervical spondylotic radiculopathy. Two months later a C5 laminoplasty and right C5/C6 foraminotomy were performed. After the surgery, the pain and involuntary movements had completely disappeared. At 2 years followup, the patient had no recurrence of pain or involuntary movements.
A 26-year-old woman was referred to our hospital after a 6-month history of left sciatica unsuccessfully treated by nonsurgical therapies. Lumbar disc herniation at L5/S1 was diagnosed and she underwent discectomy. Two weeks later, she felt pain in her left leg and involuntary movement of her left toes appeared. The movement was a combination of flexion-extension and adduction-abduction, and each toe motion was independent (Video 2, Supplemental Website Materials; supplemental materials are available with the online version of CORR). Moreover, the movement could not be stopped by conscious effort and the patient could not voluntarily reproduce the movement on the unaffected side when asked to do so. However, the movement did disappear during sleep. Lumbar MRI and myelography showed no indications of nerve root compression. The neurologist to whom we referred the patient ruled out any psychogenic disorder and other neurologic movement disorders by MRI of the brain. The pain was not relieved and the involuntary movement was not resolved by a caudal block and administration of clonazepam, diazepam, haloperidol, and adenosine triphosphate disodium. A left S1 nerve root block had a temporary effect, resulting in disappearance of the pain in her leg and the involuntary movement of the toes for a few days. Therefore, we performed the same nerve root block seven times, and 4 months after administration of the first nerve root block, the pain and involuntary movement had completely disappeared. Three months after disappearance of the pain and involuntary movement, the patient was lost to followup because she changed her residence.
PLME is defined as the association of aching or burning pain in at least one limb and involuntary movement of at least one finger or toe. The involuntary movement is spontaneous and continuous and characterized by flexion-extension and/or abduction-adduction movement of affected fingers or toes. Typically, the movement increases in proportion to the degree of pain and cannot be reproduced on the unaffected side. Some of the patients can stop the movement for a short time by conscious effort and the movement disappears during sleep. There are some reports of patients with PLME without pain, called painless limbs/moving extremities [2–5, 21, 31, 41].
We identified 12 patients with PLME of the upper extremity (PAMF), and of these patients, only one was successfully treated surgically  (Table 1). There are more reported cases of PLME in the lower extremity (PLMT) than in the upper extremities (PAMF). However, there have been no reports of PLMT being successfully resolved surgically, and only two reports of PLMT being partially or temporary improved surgically [14, 42] (Table 2).
PLME is a relatively rare disorder; therefore, the pathophysiology is not fully understood. Based on the effectiveness of the lumbar sympathetic ganglion block, Spillane et al.  speculated that abnormal impulses from afferent fibers in the sympathetic nervous system activated ventral horn cells in the spinal cord, resulting in the involuntary movement. Nathan  proposed that abnormal stimulation to the nerve root or peripheral nerve caused pain in the limbs and evoked involuntary movement by stimulating ventral horn cells via the spinal interneuron. Meanwhile, as involuntary movement does not appear during sleep, Schott suggested it was associated with the reticular activating system , which is controlled by consciousness.
In our patients, the pain and involuntary movement disappeared after decompression or block of the spinal nerve root, supporting Nathan’s theory regarding the pathomechanism of PLME (Fig. 2). He theorized that ectopic impulses of the nerve root caused by irritation are conducted to the spinal dorsal horn neurons through the afferent pathway, leading to pain perception. At the same time, the impulses from the nerve root would excite the local spinal interneuron and lead to stimulation of spinal ventral horn neurons, resulting in involuntary movement of the extremity.
Nonsurgical treatments, including administration of benzodiazepine or γ-aminobutyric acid and sympathetic ganglion block, are commonly performed [6–8, 13, 15, 18, 19, 22, 24–29, 32, 35–37, 40, 42] for patients with PLME because the central nervous system or sympathetic nervous system also is considered to be the cause of PLME, as mentioned above. However, symptoms of PAMF (Table 1) and PLMT (Table 2) usually are resistant to such treatments.
Dressler et al.  reported that sympathetic ganglion block was effective in approximately 50% of patients with PLME but the effects were transient. Guieu et al.  treated two patients with PLMT by injection of adenosine triphosphate. The pain disappeared but the effect on movement was not mentioned. Okuda et al.  suggested several advantages of epidural block over sympathetic ganglion block, and Takahashi et al.  reported the benefit of epidural spinal cord stimulation for PLMT. Recently, treatment with botulinum toxin A (BTA) injection was reported by Singer and Papapetropoulos  and Eisa et al. . The injection resulted in substantial pain relief and reduction of involuntary movement owing to reduction of the muscle spindle leading to decreased activity of the gamma loop and central sensitization.
Sudo et al.  reported the only case of a patient with PAMF in whom pain and involuntary movement were resolved by surgery. In their patient, cervical radiculopathy or segmental myelopathy was thought to be the cause of the symptoms, and bilateral open-door laminoplasty was performed. Similarly, the symptoms in our first patient were resolved by decompression of the nerve root. Therefore, we believe surgical treatment should be considered for patients in whom compression of nerve tissue is recognized by MRI and/or CT but in whom no response is obtained by nonsurgical treatment.
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Each author certifies that his or her institution approved the reporting of this case report, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.