Lumbosacral extradural arachnoid cysts: diagnostic and indication for surgery

Abstract

] or lumbosacral extradural [5,12,15,16,25,38,50] arachnoid cysts can take the form of space-occupying cystic dilatations of the lumbosacral nerve roots at or distal to the junction of the posterior root and the dorsal ganglion. Both terms are used for the same entity. They are a rare disease. Although this entity has been known since 1937 [16], there are only a few publications describing the clinical course of more than one or two cases [7,24,36,45,47]. In 1959 Nugent reported on seven surgical cases [31]. Recently, Kendall et al. discussed six of their own cases of operated extradural arachnoid cyst, but only two of them were situated in the lumbosacral region [24]. Palmer studied the frequency of spinal arachnoid cysts at the Department of Neurosurgery at the Radcliffe Infirmary in Oxford (UK) in the years 1938-1970, and found only one extradural lumbar arachnoid cyst [32]. The clinical significance remained doubtful [9,34].The availability of MRI has resulted in an increasing number of patients with incidentally diagnosed extradural arachnoid cysts. A total MRI incidence of 4.6% and 1% with symptoms is reported [34]. The higher number of nearly 10%, cited by Xiao in another myelographic study, includes very common small radicular abnormalities [51]. Patients may suffer from different types of low back pain and sciatica. No critical discussion of the indication for surgery has been found in literature so far. Our aim was to compare the results in patients with operative and conservative treatment to define standards for a good surgical result. On account of the low frequency of this entity a prospective study is impossible. Materials and methodsThe clinical records of all patients with a lumbosacral extradural arachnoid cyst attending the neurosurgical department of our hospital in the years 1987-1995 were surveyed. Over these 9 years we operated on 2995 patients with lumbar space-occupying lesions. In Abstract No critical discussion of the indication for the surgical treatment of lumbosacral extradural arachnoid cysts is found in the literature. Therefore, we want to compare the results in patients with operative and conservative treatment to define standards for a good surgical result. Over a period of 9 years, we operated on eight patients with a lumbosacral extradural arachnoid cyst and treated eight others conservatively. Only three of the operated patients experienced a postoperative relief of pain, but none was symptom free. The only one with continuing success had a preoperative history of 1 year only. MRI scans without contrast agent were misinterpreted in one included and one excluded case. The results of conservative treatment were nearly the same as those of operative treatment. MRI is the best diagnostic tool, but a variety of sequences must be used. Patients with a short pain history and a clear neurological deficit profited most from surgery. Patients with slight and not clearly related uncharacteristic symptoms should be excluded from surgery. Key words

Tarlov cysts: a controversial lesion of the sacral spine

“…18 To our knowledge, only 1 study has reported on the results of surgical treatment compared with conservative management. Kunz et al 12 did not observe significant differences in terms of symptomatic improvement between the 2 groups (total 16 patients). Due to unfavorable results in terms of pain relief observed after surgical treatment, they recommended surgery only for those patients with a short history and with a neurological deficit.…”

“…Although some authors have not described good results in association with direct surgical treatment, 12 several authors have recommended it for selected symptomatic patients. Numerous strategies of direct surgical approaches have been proposed (Table 1).…”

“…Despite low rates of cyst recurrence (range 0%-10% 3,6,12,21 ), different rates of symptomatic improvement have been reported in association with microsurgical treatment (Table 1), varying from 38% to 100%. These results should also be correlated to the patient's preoperative symptoms.…”

“…Due to unfavorable results in terms of pain relief observed after surgical treatment, they recommended surgery only for those patients with a short history and with a neurological deficit. 12 Unfortunately, all these recommendations are based on results obtained from a small number of patients and, overall, from retrospective reviews.…”

Sacral Perineural Cyst Accompanying Disc Herniation

“…Because of the rarity and unclear pathogenesis and pathophysiology of these cysts, there has been no definite consensus on the optimal treatment of symptomatic sacral perineural cysts. Surgical options include only simple decompressive laminectomy, both cyst and nerve root resection, incision and drainage of the cyst with imbrication of the redundant nerve root sheath, lumboperitoneal CSF shunting, and closure of the communication of the cyst with the dural sac [6][7][8][9]12,14) . However, simple decompression alone has proven not to be successful and cyst and nerve root resection may result in a neurological aggravation, and it is difficult to obtain watertight closure of the nerve root sleeve [8][9][10] .…”