Outline:  
Piriform muscle syndrome refers to a disease of pain in the buttock and leg due to stimulation and compression of sciatic nerve trunk resulting from injury and inflammation of piriform muscle. It is commonly caused by sharp intorsion, extorsion or abduction of hip joint and the invasion of exogenous pathogenic wind, cold and dampness, which leads to injury, spasm, thickening and contracture of piriform muscle, resulting in compression of sciatic nerve through the lower piriform aperture. As a result, there are pain in the buttock and radiating pain in the lower limb. It concludes that if there is a problem of sciatic nerve running out of the greater sciatic aperture, piriform muscle syndrome may likely happen.

Major points for diagnosis    
1. Most patients have the traumatic history of the hip.
 
2. There is pain in the buttock, which can radiate to the lower limb where the sciatic nerve passes, and can be aggravated by tiredness or invasion of pathogenic wind and cold. The serious patients have cutting or burning pain, restless sleep, and claudication in walking.
 
3. There are tenderness and radiating pain in piriform muscle, cord-like lump with thick sensation, or diffuse swelling in the belly of muscle. The muscle bundle becomes hardened. Raising test of the straightened leg is positive.
 
4. In the waist, there is no obvious tenderness and deformity, no limitation of movement. This can be differentiated from prolapse of lumbar intervertebral disc.


Treatment  
Tendon-smoothing manipulation:    
The patient lies in a prone position. The operator first presses, rubs, pushes and kneads the painful points for 4 or 5  minutes, then, with his thumb or tip of elbow pokes the piriform muscle to and fro, with a direction perpendicular to the course of piriform muscle fibers, for 10 to 20 times. Then he presses the painful points for three times, one minute for each point. Finally, he pushes, presses and smoothes the piriform muscle from the lateral to the medial, and along the course of muscle fibers, once a day, 10 times making up a course.
 

Herbal therapy
Internal treatment based on syndrome differentiation
(1) Syndrome of blockage of stagnant blood
Main symptoms and signs:
Pain in the buttock radiating to the lower limb, obvious swelling, difficulty in walking, fixed stabbing or cutting pain, or ecchymoses on the tongue, stringy or choppy pulse.

Therapeutic methods:
Promoting blood flow to remove the stasis, and removing swelling to stop pain.
 
Recipe and herbs:
Modified Taohong Siwu Decoction. The herbs see the treatment of syndrome of qi and blood stagnation in neck sprain and contusion.
 
(2) Syndrome of blockage of pathogenic cold and dampness
Main symptoms and signs: Pain in the buttock referring to the lower limb, heavy sensation, lassitude, preference to warmth and intolerance of cold, difficulty in walking, pale tongue with thin and greasy coating, slow or soft pulse.

Therapeutic methods:
Expelling cold and dampness, dispelling wind to resolve blockage.

Recipe and herbs:
Modified Xuanbi Decoction. Specifically, Fangfeng ( Radix Ledebouriellae Divaricatae )10 g, Cangzhu ( Rhizoma Atractylodis )10 g, Guizhi(Ramulus Cinnamomi Cassiae )6 g, Duhuo ( Radix Angelicae Pubescentis )10 g, Danggui (Radix Angelicae Sinensis )10 g, Zhichuanwu ( Radix Aconiti Carmichaeli Praeparata )5 g, Zhicaowu ( Radix Aconiti Kusnezoffii Praeparata )5 g, Luoshiteng ( Caulis Trachelospermi Jasminoidis )10g, Yiyiren (Semen Coicis Lachrymajobi)30 g and Gancao (Radix Glycyrrhizae)5g.
 
(3) Syndrome of collateral disharmony
Main symptoms and signs:
Aching and dull pain in the waist and lower limb aggravated by tiredness and relieved by rest; pale tongue, moderate or choppy pulse.

Therapeutic methods:
Relaxing tendons and activating collaterals.
 
Recipe and herbs:
Modified Huoxue Shujin Decoction. Specifically, Qianghuo (Rhizoma seu Radix Notopterggii )6 g, Jingjie ( Herba Schizonepetae )10 g, Honghua ( Flos Carthmi )10 g, Zhike ( Fructus Citri Aurantii)10 g, Duhuo ( Radix Angelicae Pubescentis )10 g, Fangfeng ( Radix Ledebouriellae Divaricatae )6 g, Niuxi ( Radix Achyranthis Bidentatae )10 g, Wujiapi ( Cortex Acanthopanacis )10 g, Duzhong ( Cortex Eucommiaeulmoidis )10 g, Danggui ( Radix Angelicae Sinensis)10g, Xuduan (Radix Dipsaci)12g, Oingpi (Pericarpium Citri Reticulatae Viride )5 g and Gancao(Radix Glycyrrhizae )3 g.
 
External therapy:    
In the early stage, Xiaoyu Zhitong Paste or Sanse Application is externally applied. In the late stage, Shangke Xiaoyan Paste or Tianhe Gutong Paste is externally used, or Zhenghonghua Oil or Zhenggu Liquor is topically applied.

Hydro-acupuncture therapy:     
A long syringe needle No. 6 is used to deeply inject 6 to 10 ml of 1% procaine plus 25 mg prednisolone into the piriform muscle, which is injected according to the body surface projection of the piriform muscle. This is suited for the acute cases for alleviating spasm, once every 5 to 7 days.
 
Acupuncture therapy:   
Acupoints Ashi, Huantiao (GB30), Yinmen (BL37), Chengfu (BL36), Yanglingquan (GB34), and Zusanli (ST36) are selected. Reducing method is used. It is better for the patient to have sore and numb sensation radiating to the distal limbs. If there is no obvious needling sensation, twirling manipulation should be used. At the acute stage, it is performed once a day. After the pain is relieved, acupuncture is performed every other day.