the perineurial or tarlov cysts are pathological entities found in the space between the perineurium and endoneurium of the posterior nerve root sheath of the root ganglion in lumbosacral lesion . they were first described by tarlov during autopsy studies of the filum terminale1 ) . since then , about 100 cases of symptomatic perineurial cysts have been reported in the literature2 ) . the development of magnetic resonance ( mr ) images has improved diagnostic ability to recognize perineurial cyst as a cause of sacral neurological dysfunction . although the majority of perineurial cysts are asymptomatic , they are able to cause radiculopathy , urinary dysfunction , and perineal or sacrococcyseal pain3,4,5,6,7 ) . although it is still a matter of debate whether patients with symptomatic perineurial cysts should be treated surgically , several authors recommend temporary or permanent lumbar cerebrospinal fluid drainage , laminectomy , microsurgical excision of symptomatic perineurial cysts or cyst fenestration and imbrication , and percutaneous fibrin glue instillation8,9,10,11,13,14 ) . we describe three cases with a perineurial cyst treated successfully with microsurgical excision and neck ligation of cyst originated from the left l5 nerve root , and introduce an operative method using sacral recapping laminectomy . this 61-year - old man presented with 2-year history of increasing lumbosacral pain and hypesthesia . on neurologic exam his symptoms were aggravated by standing , walking , climbing , coughing and lifting , and relieved by sitting . the patient rated his pain 7 of 10 on the visual analogue score ( vas ) . he had bladder dysfunction and abnormal sensation for urination , and reported insertion of a foley catheter 2 months ago . preoperative mr imaging demonstrated 301711 mm sized sacral cyst with another small cyst from l5 to s2 level ( fig . myelogram and ct showed the contrast - filled bridge between the thecal sac and the cystic mass and sacral cyst causing compression of adjacent nerve roots ( fig . after careful dissection of the cyst wall , we observed the superior surface of the cyst compressing s1 nerve root ventromedially and s2 nerve root dorsally ( fig . it was connected with a small cyst that was adhesive to right s2 and s3 nerve roots . we ligated the neck of the cyst and its wall was cut down away from the adjoining root sleeve . the sacral lamina was recapped at the back again with using heavy silk sutures ( fig . follow up mr imaging after 6 months demonstrated complete resolution of the cyst ( fig . at one year follow up , he had mild back pain ( 2 of 10 on the vas ) . this 21-year - old man complained of worsening radiating pain and hypesthesia on left leg for 1 year . his motor weakness was grade 4 on left leg , especially when extending the left ankle . because of worsening symptoms he eventually visited our department . he had mild claudication , positive on left straight leg raising test at 45 degree . we performed myelogram and ct and found the contrast - filled stalk between the thecal sac and the cyst . we checked with mr imaging after 1 year and ascertained that there was no further cystic formation and complication ( fig . this 60-year - old female patient visited our department with 6-year history of increasing lumbosacral pain and right leg radiculopathy . on neurologic examination preoperative mr imaging demonstrated 151722 mm sized sacral cyst with s1 nerve root ( fig . myelogram and ct showed the contrast - filled bridge between the thecal sac and the cystic mass , and sacral cyst causing compression of adjacent nerve roots ( fig . we performed surgery the same way but we used miniplate instead of silk for recapping ( fig . follow up , she had only mild back pain ( 3 of 10 on the vas ) . under general anesthesia , the chiseling point of sacral lamina is approximately 3 mm medial to dorsal sacral foramina . the line of chiseling was extended caudally to the involved sacral level . at this time , care should be taken to preserve the integrity of the underlying sacral nerve roots and perineurial cyst . care must be taken to avoid injury of several nerve roots that lie along the dorsal and ventral aspects of the cyst wall . the sutured area of the cyst was secured with an oxidized cellulose and glue combination . this 61-year - old man presented with 2-year history of increasing lumbosacral pain and hypesthesia . on neurologic exam his symptoms were aggravated by standing , walking , climbing , coughing and lifting , and relieved by sitting . the patient rated his pain 7 of 10 on the visual analogue score ( vas ) . he had bladder dysfunction and abnormal sensation for urination , and reported insertion of a foley catheter 2 months ago . preoperative mr imaging demonstrated 301711 mm sized sacral cyst with another small cyst from l5 to s2 level ( fig . myelogram and ct showed the contrast - filled bridge between the thecal sac and the cystic mass and sacral cyst causing compression of adjacent nerve roots ( fig . after careful dissection of the cyst wall , we observed the superior surface of the cyst compressing s1 nerve root ventromedially and s2 nerve root dorsally ( fig . it was connected with a small cyst that was adhesive to right s2 and s3 nerve roots . we ligated the neck of the cyst and its wall was cut down away from the adjoining root sleeve . the sacral lamina was recapped at the back again with using heavy silk sutures ( fig . follow up mr imaging after 6 months demonstrated complete resolution of the cyst ( fig . at one year follow up , he had mild back pain ( 2 of 10 on the vas ) . this 21-year - old man complained of worsening radiating pain and hypesthesia on left leg for 1 year . his motor weakness was grade 4 on left leg , especially when extending the left ankle . because of worsening symptoms he eventually visited our department . he had mild claudication , positive on left straight leg raising test at 45 degree . we performed myelogram and ct and found the contrast - filled stalk between the thecal sac and the cyst . we checked with mr imaging after 1 year and ascertained that there was no further cystic formation and complication ( fig . 2c ) . this 60-year - old female patient visited our department with 6-year history of increasing lumbosacral pain and right leg radiculopathy . on neurologic examination , she complained right l5 and s1 radiculopathy . preoperative mr imaging demonstrated 151722 mm sized sacral cyst with s1 nerve root ( fig . myelogram and ct showed the contrast - filled bridge between the thecal sac and the cystic mass , and sacral cyst causing compression of adjacent nerve roots ( fig . we performed surgery the same way but we used miniplate instead of silk for recapping ( fig . follow up , she had only mild back pain ( 3 of 10 on the vas ) . the chiseling point of sacral lamina is approximately 3 mm medial to dorsal sacral foramina . the line of chiseling was extended caudally to the involved sacral level . at this time , care should be taken to preserve the integrity of the underlying sacral nerve roots and perineurial cyst . upon opening , care must be taken to avoid injury of several nerve roots that lie along the dorsal and ventral aspects of the cyst wall . the sutured area of the cyst was secured with an oxidized cellulose and glue combination . since tarlov cyst was first described in 1938 , it has been mainly reported for its clinical aspects , pathological mechanisms and operative methods1 ) . however in a small minority , non - specific , variable clinical symptoms occasionally develop . patients may complain of progressive pain in the lower back , sacrum , lower extremities , coccyx , rectum , and vagina , or penis2,3,4,5,6,7,8,10,11,13,14,15 ) . it has been postulated that pressure on the adjacent sensitive tissue , such as the periosteum and the joint capsule , causes local back pain1,12 ) . the patients with perineurial cyst can also experience other sensory disturbances such as hypesthesia or paresthesia over the buttocks , perineal area , and lower extremities3,5,8,14,15 ) . our patient complained of lumbosacral pain , hypesthesia and radiculopathy showing progressive bladder dysfunction and abnormal sensation upon urination . it was known that diverticula and small meningoceles are rarely symptomatic as their inner pressure equals the intra dural pressure because of the free communication with csf10,14 ) . on the other hand , a perineurial cyst can cause a significant mass effect even if relatively small . their internal pressure being substantial , they can exert pressure on neural tissue as well as surrounding bone14 ) . the cause of sacral perineurial cysts is unknown , but several theories have been suggested . tarlov16 ) insisted that sacral perineurial cysts occur because of breakage of venous drainage in the perineurium and epineurium secondary to hemosiderin deposition after trauma . fortuna et al.6 ) considered sacral perineurial cysts to result from congenital arachnoidal proliferation along the exiting sacral nerve roots . paulsen et al.14 ) proposed that the cysts enlarge due to a ball - valve effect , whereby csf enters the cyst with systolic pulsation but disables to exit through the same entrance of the cyst during diastole . congenital arachnoidal defect and valve mechanism of the cyst may play an important role in the pathogenesis of sacral perineurial cyst . a variety of surgical techniques have been described to treat tarlov cyst . in tarlov 's original article , he used either complete or partial excision of the cyst or incision and drainage without excision . since this original article , several authors proposed microsurgical cyst excision , cyst fenestration and imbrications8,11,13,14 ) . more recently , a nonsurgical treatment with percutaneous ct - guided meningeal cyst aspirations is reported as a method of relieving symptoms10 ) . but , some opponents suggested that patients did not benefit from surgery because of recurrence of symptoms or surgical complications2,16 ) . also , temporary lumbar drainage can reduce the symptom by shrinkage of sacral cyst , but the symptom would occur again after removal of drainage that is why the symptomatic sacral cyst should be surgically treated2 ) . voyadzis et al.17 ) observed no relief of pain in his study and found that patients with tarlov cysts greater than 1.5 cm and with associated radiculopathy or urogenic symptoms are able to profit from surgical treatment2 ) . to our knowledge , but it is difficult to reproduce this technique because they did not exactly describe the laminectomy method and the intraoperative photographs were dim black - and - white . in contrast to this , the present report demonstrates procedures in detail and step - by - step way . if there is no bony erosion , it may protect the sacral nerve roots and dural sac from external pressure , postoperatively . it may be also expected to protect neural tissue against severe adhesion with soft tissue . furthermore , recapping prevents the adhesion problem , so revision surgery would be performed easily in case of recurrence . perineurial cysts have become a common incidental findings during lumbosacral mr imaging . only some of the symptomatic cysts require surgical treatment . we have described the successful treatment of symptomatic perineurial cyst , and introduced sacral recapping laminectomy .
perineurial cysts ( tarlov cysts ) are lesions of the nerve root that are often observed in the sacral area . 
 there is debate about whether symptomatic perineurial cysts should be treated surgically . 
 we presented three patients with symptomatic perineurial cyst who were treated surgically , and introduced sacral recapping laminectomy . 
 patients complained of low back pain and hypesthesia on lower extremities . 
 we performed operations with sacral recapping technique for all three . 
 the outcome measure was baseline visual analogue score and post operative follow up magnetic resonance images . 
 all patients were completely relieved of symptoms after operation . 
 although not sufficient to address controversies , this small case series introduces successful use of a particular surgical technique to treat sacral perineural cyst , with resolution of most symptoms and no sequelae .