Electrophysiological evidence of a relationship between idiopathic carpal and tarsal tunnel syndromes

Tarsal Tunnel Syndrome Associated With a Bipartite Talus

BACKGROUND

Talus bipartitus is a rare skeletal anomaly that may be mistaken for an os trigonum, a relatively common accessory ossicle found posterior to the talus. Both are believed to be formed similarly with the failed fusion of the talus with a second ossification center. Os trigonum is often diagnosed incidentally or found on radiographs obtained in symptomatic patients with signs of os trigonum syndrome, which presents with posterolateral ankle pain. A bipartite talus may also present with similar symptoms but may be differentiated through its articular involvement.

CASE

In this article, we describe the rare presentation of tarsal tunnel syndrome in a patient caused by a bipartite talus. The patient underwent surgical decompression with the removal of the posterior fragment.

CONCLUSION

A bipartite talus is a rare entity that may be mistaken for an os trigonum, a common accessory ossicle. In this article, we describe an outcome of a bipartite talus fragment removal due to tarsal tunnel syndrome and illustrate a rare pathological consequence of a bipartite talus. We further highlight the importance of early surgical management in patients presenting with an identifiable structure contributing to tibial nerve compression.

Double crush syndrome in the lower extremity: a case report

Upton and McComas first described double crush syndrome in 1973. The theory behind double crush syndrome postulated that a proximal lesion in a nerve would make that same nerve more vulnerable to additional distal lesions. Many of the studies investigating the possibility of the double crush syndrome involve lesions in the upper extremity with very few articles written specifically about double crush syndrome in the lower extremity. We present the case of a 33-year-old massage therapist who uses her feet to provide therapy to clients who presented to our clinic with symptoms consistent with tarsal tunnel syndrome. Her failure to progress in a satisfactory manner after a variety of therapies made us search for additional etiologies for her foot pain. In cases where tarsal tunnel persists after surgical therapy, the treating physician should search for more proximal lesions along the course of the nerve.

Neuropathies of the foot

Compared with the common neuropathies affecting the hands (carpal tunnel syndrome and ulnar neuropathy), neuropathies of the feet have received less attention in the past. This is partly because of the rarity of these disorders as well as the lack of reliable electrophysiological tests for them. Over the years, nerve conduction tests for various nerves of the feet have been reported, and at this time techniques for all the nerves of the feet are available to the electromyographer. This review will provide up-to-date information on the current status of the research and issues relating to the neuropathies of the foot, with an emphasis on the most useful tests and the caveats for clinical neurophysiologists.

Sympathetic pathology evidenced by hand thermal anomalies in carpal tunnel syndrome

OBJECTIVE

To clarify sympathetic pathology in carpal tunnel syndrome and the usefulness of digital infrared thermography as a diagnostic aid.

MATERIAL AND METHODS

38 clinically diagnosed carpal tunnel syndrome hands from 30 patients (confirmed by the standard nerve conduction studies) and 41 hands from 22 healthy volunteers (the hands having current finger inflammation were excluded) were studied. A series of hand infrared photos of each subject were taken and stored by using the technique of digital infrared thermography. We studied the infrared pictures and measured the temperatures of finger tips from digit 1 (D1) to digit 5 (D5), the center point of thenar (Th) and hypothenar eminences (Ht), then we calculated the temperature differences (absolute values) between each two of the 7 points, and median index (MI): (D1-D2)+(D2-D3)+(D1-D3). The means of D2 and Th (MD2+Th), D5 and Ht (MD5+Ht) were also calculated.

RESULTS

The results showed that the temperatures of median nerve distribution area in the hands were highly significantly different (Th-Ht, p < 0.001, MI, p < 0.001) between carpal tunnel syndrome (CTS) and the control group. The differences between the median and ulnar nerve distribution area were also highly significantly different in CTS hands (MD2+Th compared to MD5+Ht, p < 0.01). The sensitivity and specificity of digital infrared thermography were 84 and 91%, respectively.

CONCLUSION

Digital infrared thermography suggests sympathetic neural pathology in carpal tunnel syndrome. It may also be useful as an additional non-invasive tool in the diagnosis of CTS especially in the early stage.

An electrophysiological severity scale in tarsal tunnel syndrome

OBJECTIVE

To propose a neurophysiological classification of tarsal tunnel syndrome.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of two electromyography laboratories. Case inclusion criteria were based on clinical parameters. Motor conduction velocity, distal motor latency (DML), sensory conduction velocity (SCV) and sensory action potential (SAP) from big toe (T1) and from fifth toe (T5) to medial malleolus were measured in the medial and plantar nerves. When SCVs of T1 and T5 were normal, we considered the difference in T1 SCV between affected and unaffected side and in T1 SCV of the affected side with sural nerve distal SCV. Feet with TTS were classified in six electrophysiological classes: 0, normal SCV and DML; 1, normal absolute SCV with abnormal comparative tests; 2, slowing of T1 and T5 SCV and normal DML; 3, slowing of SCV and DML; 4, absence of T1 and T5 SAPs and abnormal DML; 5, absence of sensory and motor response.

RESULTS

A total of 111 feet belonging to 96 patients (27 men, 69 women; mean age 49.6 years) were diagnosed with TTS. T1 and T5 SCV were abnormal in 82 and 73% of cases, respectively, and comparative tests were abnormal in a further 7% of cases. DML was abnormal in 82 feet (73.9%). Eight feet (7%) were without neurographic abnormalities. The distribution of feet in neurophysiological classes was: stage 0, 7%; stage 1, 9%; stage 2, 10%; stage 3, 39%; stage 4, 32%; stage 5, 3%. Higher clinical scores coincided with higher neurographic classes.

CONCLUSION

The progression of neurographic abnormalities in TTS reflects the relation between SCV and DML, and between neurographic values and clinical severity. The scale assigns severity classes in a reliable and non-arbitrary way. This classification can easily be used by electrophysiological laboratories with their own electrophysiological techniques and normal values.