Spinal neurenteric cysts: Associated developmental anomalies and rationale of surgical approaches.

Abstract

Neurenteric cysts (NC) occur due to failure of separation of neurectoderm from endoderm at the 3rd week of embryogenesis. This study focuses on key clinico-radiological features of NCs, with emphasis on surgical nuances involved in resecting anteriorly placed NC, especially at the foramen magnum (FM). Sixteen consecutive patients having a spinal NC were included. Their clinico-radiological status, surgical nuances and follow-up status were noted. The duration of spasticity/paraparesis/quadriparesis ranged from 15 days to 48 months. Twelve patients had an intradural extramedullary (IDEM; nine anterior and three anterolateral) cyst and four had an intramedullary (IM) cyst. Six of them had an anteriorly placed FM lesion (five IDEM and one IM). Amongst ten subaxial NCs, four were anterior, two antero-lateral and one postero-lateral; three were IM. Three patients had the characteristic stigmata of occult spinal dysraphism: two, a large mesenteric cyst, and one, a posterior mediastinal cyst. Excision was total in 13 patients. Subtotal excision of tumour capsule was performed for two recurrent cysts and an IM cyst. A far lateral approach was adopted for anteriorly placed FM lesions and posterior laminectomy for subaxial lesions. Histopathology revealed eight type A cysts, four type B cysts and four type C cysts. At follow-up (range, 8 months to 12 years; median, 60 ± 45.84 months), complete neurological recovery occurred in seven patients; six patients had persistent spasticity but only minor disability; two patients had difficulty in walking; and one patient with an anteriorly placed thoracic recurrent NC had sustained neurological deterioration. Surgical difficulties in addressing NCs are related to their anterior or IM location, presence of adhesions and inability to dissect the tumour capsule from the spinal cord due to fibrous or lipomatous connections. The associated developmental anomalies must be specifically sought and addressed.