Double-Crush Syndrome in Lower Limbs
I did a retrospective analysis of results of EMG-NCV tests performed in lower limbs in our clinic to statistically estimate double-crush hypothesis there (Golovchinsky, 1998). Many such patients had suffered various kinds of traumas and injuries, usually work-related or caused by automobile accidents. The patients were typically referred for the test with lower back pain as a major complaint. Other common complaints included pain radiating to lower limbs, or numbness and weakness of lower limbs. Patients whose only problem was injury to the knee or ankle, as well as patients with general medical problems affecting peripheral nerves (diabetes, hypothyroidism, generalized peripheral neuropathies) were excluded from the study. Included in the study were 97 males and 72 females, whose ages ranged from 18 to 77 years (mean 41.07 years, SD 12.24). In all except 18 patients, the test was performed bilaterally. In patients where motor nerve conduction velocity was decreased in one or two nerves only, these nerves were also excluded from the study. A total of 289 peroneal and 280 tibial nerves were included in the statistical analysis. Muscles routinely tested with monopolar needle electrode included lumbo-sacral paraspinals bilaterally from Ll through Sl bony levels and gluteus maximus, quadriceps femoris, adductor longus, anterior tibial, peroneus longus and lateral and medial bellies of gastrocnemius. When necessary, additional muscles were explored as well. Routine conduction velocity testing was done in peroneal and tibial nerves (Johnson, 1980). Sensory fibers of the sural nerve were tested orthodromically. F-wave latency, as an indicator of possible impairment of the proximal nerve segment or the spinal nerve root injury (Aminoff et al., 1985; Fisher et al., 1978; Fisher, 1992; Tonzola et al., 1981), was evaluated using routine technique (Fisher, 1992). Normal for F-wave latency of the peroneal nerve was calculated according to Panayiopoulos et al. (1977). For the tibial nerve, normal F-wave latency was considered 58 msec or less (Kimura, 1983). Additionally, the difference between sides of 3.5 msec or more was also considered abnormal (Kimura, 1983).
KeywordsNeuropathy Neurol Hypothyroidism Weinstein
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