Are Tarlov Cysts Being Identified and Reported on Lumbar Spine MRI Scan in Patients with Sciatica
Authors: Clarke Gareth , Kapoor Vikas , Baxter Jon 
Published: April 2016

Introduction Following advances in surgical technique sacral Tarlov Cysts (TCs) are now a treatable cause of back pain and sciatica.1,2 However many surgeons and radiologists still view them as an incidental finding. This audit was performed to raise awareness of TCs within the hospital and further afield, assess the extent to which TCs are present in patients with sciatica and assess if they are being identified and reported by the radiologist and surgeon in every case. Material and Methods Following a literature review a list of all spinal MRI scans requested by the three consultant spinal surgeons working at the hospital between 1/1/2013 – 31/12/2014 was compiled by the radiology department. All patients with complaints of radicular pain or altered sensation in one or both lower limbs in their initial clinic letter then had their MRI scan reviewed using the hospital PACS system for the presence of TCs. The radiologist's report and follow-up clinic letter were then reviewed in patients with a TC present on their scan to see if it was reported by the radiologist and surgeon. Any patient who's scan or clinic letters were not were removed from the audit. Results In total 1499 patients underwent lumbar-sacral MRI scan under the care of the spinal surgeons. Of these, 1070 fitted the inclusion criteria. 6 MRI scans were not accessible, in total 1064 MRI scans were reviewed for the presence of TCs. 158 scans showed sacral TCs present, an incidence of 14.85%. Of the 158 only 33 (21%) had TCs in the radiologists' report. 4 were reported as possibly symptomatic and the rest as an incidental finding. Only the 4 potentially symptomatic TC patients were notified of the presence of the cysts during their clinic appointment following the MRI scan. No other patients notified of the presence of TCs on their MRI. Therefore of the 158 patients with sacral TCs present only 4 (2.5%) were made aware of the lesion. Only one case of symptomatic cyst was identified as the patient's symptoms decreased following excision of the cyst. Conclusion Several things were apparent from the literature review; the exact anatomical area supplied by each of the lumbar-sacral dermatomes is not known and as such pathology compressing the S2 nerve root can cause symptoms suggestive of an S! or even L5 radiculopathy,3 TCs can be progressive in nature,4 microsurgical treatment gives the best relief of symptoms and can give complete relief of symptoms,5,6 early intervention gives the best prognosis.1 From the audit it was apparent that in almost 80% of cases TCs were not being reported, this could potentially lead to patients continuing with symptoms, or developing them as the cyst progresses. A delay in diagnosis and therefore treatment of a symptomatic TC could lead to a poorer prognosis. It seems that for many Tarlov Cysts are still viewed as an asymptomatic incidental finding, until this opinion is changed it will continue to be under reported and patients will continue to suffer a potentially treatable spinal pathology. References Sun JJ, Wang ZY, Teo M, et al. Comparative outcomes of the two types of sacral extradural spinal meningeal cysts using different operation methods: a prospective clinical study. PLoS ONE 2013;8(12):e83964 Lucantoni C, Than KD, Wang AC, et al. Tarlov cysts: a controversial lesion of the sacral spine. Neurosurg Focus 2011;31(6):E14 Turek S. Orthopaedics: Principles and Their Application. 3rd ed. Philadelphia: JB Lippincott; 1977 Freidenstein J, Aldrete JA, Ness T. Minimally invasive interventional therapy for Tarlov cysts causing symptoms of interstitial cystitis. Pain Physician 2012;15(2):141–146 Caspar W, Papavero L, Nabhan A, Loew C, Ahlhelm F. Microsurgical excision of symptomatic sacral perineurial cysts: a study of 15 cases. Surg Neurol 2003;59(2):101–105, discussion 105–106 Neulen A, Kantelhardt SR, Pilgram-Pastor SM, Metz I, Rohde V, Giese A. Microsurgical fenestration of perineural cysts to the thecal sac at the level of the distal dural sleeve. Acta Neurochir (Wien) 2011;153(7):1427–1434, discussion 1434