the patient was a 51-year - old man with a 1-month history of lower back pain . at the onset , the pain radiated to the right buttock with a tingling sensation down his right lower limb posteriorly to his ankle . he did not report any difficulty with bowel , bladder , or sexual function . on physical examination , a straight leg - raising test of the right leg was positive at 60 degrees . the deep tendon reflexes were 2 + on the both knees and ankles . a magnetic resonance imaging ( mri ) scan demonstrated a mass at the level of the l4 - 5 interspace and , compression of the thecal sac and the nerve root on the right side ( fig . 1 ) ; it was not possible to determine whether the lesion was completely extradural or partially intradural . owing to the signal characteristics , a synovial cyst arising from the medial aspect of the facet joint was suspected to adhere to the entire length of the nerve root sleeve . a 22-gauge 3.5-inch spinal needle was advanced under fluoroscopic guidance into the right l5/s1 zygapophysial joint . by injecting the right l5/s1 zygapophysial joint with contrast , a right synovial cyst was introduced into the cyst directly with a right paramedian , interlaminar approach under fluoroscopic guidance ( fig . serosanguinous fluid 1.0 ml was aspirated , and triamcinolone acetate 10 mg was injected into the cyst . the patient felt an immediate relief of symptoms after the aspiration , and had no signs or symptoms of recurrence at the follow - up 6 months later . no demonstrable lesion was found in the 6 months follow - up mri ( fig . lumbar z - joint synovial cysts usually originate from the z - joint capsule . the cyst can be lined with synovium and contain serous , gelatinous , or hemorrhagic fluid . the development of z - joint synovial cysts is linked to degenerative spondylosis , segmental instability and perhaps trauma . at least 1% of all lumbar radicular pain may be the result of z - joint synovial cysts . z - joint synovial cysts are frequently associated with a narrowed spinal canal caused by stenosis , so z - joint synovial cysts easily become symptomatic . accurate diagnosis of z - joint synovial cyst results in a number of therapeutic implications . facet joint injection with steroid and long - acting anesthetic can provide temporary or prolonged pain relief   which may be of value in patients unfit for surgery . indirect aspiration via the facet joint can be effective , and direct aspiration under fluoroscopic guidance has been successful . surgery , to relieve sciatica caused by a z - joint synovial cyst is effective in a high proportion of patients . minimally invasive techniques for the treatment of lumbar synovial cyst seem to eliminate many of the risks of traditional surgical techniques . in this case , direct needle aspiration of the cyst was performed , and this less invasive procedure may be employed as an alternative to surgery . since the cyst may spontaneously decompress , conservative treatment can be beneficial . z - joint synovial cysts are treated with an interlaminar or intra - articular approach . however , in using the intra - articular approach , aspiration of cyst fluid is often difficult because of the relative ball - valve effect , which occurs as negative pressure is applied . described a technique used to rupture the cyst by injecting the joint or inferior joint recess with as much as 3 ml of betamethasone and bupivacaine , followed by 1 - 5 ml injection of normal saline . rupture of the cyst was accomplished in 50% of cases , with pain relief in 9 out of 12 patients . jacob et al .   introduced a 20-gauge spinal needle into the cyst and aspirated 1.0 ml of fluid under ct guidance . the patient was asymptomatic within 3 days , and remained pain free at the 18-month follow - up . koenigsberg   positioned a 22-gauge spinal needle into the cyst and fluid was aspirated under ct guidance with no contrast solution used . the patient had immediate partial pain relief , followed by complete relief on the third day following the procedure . lim et al .   passed a 22-gauge needle into a cyst under ct guidance , and injected 20 mg of triamcinolone and 1 ml of bupivacaine . the patient reported immediate complete relief of pain , and remained pain - free for 9 months after the treatment . after multiple interventions to aspirate and drain the cyst through the z - joint , gishen and miller   used ct guidance to aspirate the cyst through the lamina with a bone biopsy needle . long - term resolution of symptoms occurred and mri taken after a year showed no recurrence . complete regression of the cyst seems to occur only with complete rupture . in our patient , cyst puncture was performed with live fluoroscopy , to ensure the position of the needle within the contrast - filled cyst . the patient derived complete resolution of his right limb radicular pain after puncture of a z - joint synovial cyst and remained pain - free at the 6 month follow - up .
a 51-year - old man with a 1-month history of lower back pain and radiating pain visited to our pain clinic . a magnetic resonance imaging ( mri ) scan demonstrated a cyst like mass at the level of the l4 - 5 interspace and compression of the thecal sac and the nerve root on the right side . 
 we performed percutaneous needle aspiration of the lumbar zygapophyseal joint synovial cyst under fluoroscopic guidance . 
 the patient felt an immediate relief of symptoms after the aspiration , and had no signs or symptoms of recurrence at the follow - up 6 months later . 
 no demonstrable lesion was found in the 6 months follow - up mri .