Jo-Tong Chen

Inhibitory effect of dry needling on the spontaneous electrical activity recorded from myofascial trigger spots of rabbit skeletal muscle.

Chen JT, Chung KC, Hou CR, Kuan CR, Chen SM, Hong CZ: Inhibitory effect of dry needling on the spontaneous electrical activity recorded from myofascial trigger spots of rabbit skeletal muscle. Am J Phys Med Rehabil 2000;80:729–735. Objective: Dry needling of myofascial trigger points can relieve myofascial pain if local twitch responses are elicited during needling. Spontaneous electrical activity (SEA) recorded from an active locus in a myofascial trigger point region has been used to assess the myofascial trigger point sensitivity. This study was to investigate the effect of dry needling on SEA. Design: Nine adult New Zealand rabbits were studied. Dry needling with rapid insertion into multiple sites within the myofascial trigger spot region was performed to the biceps femoris muscle to elicit sufficient local twitch responses. Very slow needle insertion with minimal local twitch response elicitation was conducted to the other biceps femoris muscle for the control study. SEA was recorded from 15 different active loci of the myofascial trigger spot before and immediately after treatment for both sides. The raw data of 1-sec SEA were rectified and integrated to calculate the average integrated value of SEA. Results: Seven of nine rabbits demonstrated significantly lower normalized average integrated value of SEA in the treatment side compared with the control side (P < 0.05). The results of two-way analysis of variance show that the mean of the normalized average integrated value of SEA in the treatment group (0.565 ± 0.113) is significantly (P < 0.05) lower than that of the control (0.983 ± 0.121). Conclusions: Dry needling of the myofascial trigger spot is effective in diminishing SEA if local twitch responses are elicited. The local twitch response elicitation, other than trauma effects of needling, seems to be the primary inhibitory factor on SEA during dry needling.

Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle.

Kuan TS, Chen JT, Chen SM, Chien CH, Hong CZ: Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle. Am J Phys Med Rehabil 2002;81:512–520. Objective To assess the effect of botulinum toxin type A (BTX-A) on the endplate noise prevalence in rabbit myofascial trigger spots to confirm the role of excessive acetylcholine release on the pathogenesis of myofascial trigger points and to develop an objective indicator of the effectiveness of BTX-A in the treatment of myofascial trigger points. Design Eighteen adult New Zealand rabbits were divided into three groups that received a single bolus of BTX-A over a myofascial trigger spot region on one side of the biceps femoris muscle. Another 10 rabbits received multiple-point injections in a myofascial trigger spot where endplate noises were found. A control study was performed on the other side of the biceps femoris muscle. The endplate noise prevalence in a myofascial trigger spot region was assessed. Results It was found that injection of BTX-A reduced the prevalence of endplate noise. No significant differences between a single bolus injection and multiple-point injections were noted, although there was some evidence that multiple-point injections might maintain the endplate noise decreasing effect much longer than a single injection. Conclusions This study demonstrated the suppressive effect of BTX-A on endplate noise prevalence in a myofascial trigger spot region. The prevalence of endplate noise in the myofascial trigger point region may be a useful objective indicator for evaluating the therapeutic effectiveness of BTX-A injection to treat myofascial trigger points.

Effects of a calcium channel blocker on electrical activity in myofascial trigger spots of rabbits.

Hou CR, Chung KC, Chen JT, Hong CZ: Effects of a calcium channel blocker on electrical activity in myofascial trigger spots of rabbits. Am J Phys Med Rehabil 2002;81:342–349. Objective This study investigated the effect of a calcium channel blocking agent, verapamil, on the spontaneous electrical activity (SEA) in a myofascial trigger spot of biceps femoris muscles of rabbits. Design Left and right legs of eight adult New Zealand rabbits were randomly assigned into either experimental or control groups to assess the effect of verapamil on SEA. Verapamil and normal saline were injected into the external iliac artery for experimental and control groups, respectively. The experiment was divided into two phases: Phase A investigated the immediate effect of verapamil on SEA of one active locus, and phase B studied the effect of verapamil on SEA of 25 different active loci. The average integrated value of SEA was used to statistically analyze the effect of verapamil on myofascial trigger-spot sensitivity. Results In phase A, conducted on one active locus, the regression analysis results showed that the average integrated value in the verapamil group linearly decreased with time, but the average integrated value did not significantly change with time in the control group. In phase B, which analyzed 25 different active loci, the results indicated that the mean average integrated values in the verapamil group was significantly lower than that of the control group. Conclusions Calcium channel blockers can effectively inhibit the SEA of myofascial trigger spots.

Femoral Neuropathy after Reconstruction of a Defect Due to Buccal Cancer Excision Using a Thigh Flap: A Case Report

A case of femoral neuropathy as a complication of flap excision for reconstruction of a defect due to buccal cancer excision is presented. A 51-year-old man developed numbness over his left anteromedial thigh and medial lower leg, left quadriceps weakness, and absence of left knee jerk after a flap was obtained from his anterolateral thigh. Electromyographic examination revealed evidence of denervation in the left quadriceps. A nerve conduction study showed prolonged latency, reduced amplitude of the compound muscle action potential, decreased velocity in the left femoral nerve and prolonged latency, reduced amplitude of the sensory nerve action potential, and decreased conduction velocity in the left saphenous nerve. It is suggested that this complication was caused by traction of the femoral nerve when the free antero-lateral fasciocutaneous flap was dissected. The complication may be preventable by avoiding overstretching the femoral nerve during dissection or by application of intraoperational electrodiagnostic monitoring.