Introduction
Sciatica is marked by pain radiating to the foot from lumbar region, buttocks, posterior side of the thigh and lateral side of the shank. The pain is usually unilateral and will be aggravated when the waist is bent or the lower limbs are moved. The causes of sciatica are various. Clinically it is divided into primary and secondary types. The secondary type is further classified into root and trunk types. Sciatica pertains to the conceptions of obstructive syndrome, lumbago and pain of loins and legs in TCM. It is mainly caused by exogenous pathogenic wind, cold and dampness that obstruct meridians; or by asthenia of kidney qi and malnutrition of meridians; or by trauma, sprain, contusion and stagnation of qi and blood in meridians.

Syndrome Differentiation
1. Obstruction by Cold-dampness
Frequent attack after invasion of cold-dampness, pain and heaviness of loins and legs, inflexibility, subjective cold sensation in the affected region, aggravation in rainy and cold weather, white or white and greasy tongue fur, deep pulse.

2. Asthenia of Kidney Qi
Slow onset, lingering duration, recurrence, aching pain in the loins, aggravation after work, weakness of waist and legs, pale complexion, light-colored tongue, deep and thin pulse.

3. Stagnation of Qi and Blood
Traumatic injury history of waist, stabbing pain in the waist and legs, aggravation in movement, purplish tongue, taut or unsmooth pulse.

Treatment
1. Body Acupuncture
Prescription: 3 - 5 lumbar Jiaji (EX-B 2), Ashi point, Huantiao (GB 30) and Yanglingquan (GB 34).

Modification: For obstruction by cold-dampness, Yaoyangguan (GV 3), Dachangshu (BL 25), Zhibian (BL 54), Chengfu (BL 36), Chengshan (BL 57), Feiyang (BL 58) and Kunlun (BL 60) are added; for asthenia of kidney qi, Shenshu (BL 23), Zusanli (ST 36) and Dazhong (KI 4) are added; for stagnation of qi and blood, Shuigou (GV 26), Weizhong (BL 40) and Geshu (BL 17) are added.

Performance: Each time 4 - 9 acupoints are selected according to the pathological conditions. For the treatment of cold-dampness, reducing needling technique, warmed needling or moxibustion with moxa roll are used with the addition of cupping; for the treatment of kidney asthenia, reinforcing needling technique, warmed needling or moxibustion with moxa cone are used; for the treatment of stagnation, bloodletting is done on Weizhong (BL 40) or on the collaterals around.

2. Electro-Acupuncture
Prescription: Lumbar Jiaji (EX-B 2), Yanglingquan (GB 34) and Weizhong (BL 40).

Performance: After needling sensation is felt, impulse current is attached to the needles for 10 - 15 minutes, once a day.