Misdiagnosis in a case of non-compressive myelopathy due to a lumbar spinal intradural fistula supplied by theArtery of Adamkiewicz

Abstract

Background:Spinal vascular malformations comprise a rare but significant group of spinal disorders where clinching the diagnosis early is absolutely necessary since the morbidity increases as the time goes by. These malformations present mainly with symptoms of myelopathy with a gradually worsening course and thus early diagnosis and intervention may revert the symptoms to some extent. Owing to ignorance, sometimes the diagnosis may be missed or delayed and this delay can make a significant difference in the final outcome.Case Description:A 44-year-old male presented to us with an 8-month history of gradually worsening difficulty in walking and lower limb paraesthesias along with recent bladder complaints. Earlier, the imaging had revealed prolapsed lumbar disc and he had undergone L4-5 micro-discectomy few months back. As his symptoms worsened further, he developed paraparesis and then a more detailed analysis revealed a missed spinal arterio-venous fistula at L4-5 level causing congestive myelopathy. He was re-operated and the fistula was disconnected which led to an improvement months after surgery.Conclusion:Thus, to differentiate between compressive and non-compressive myelopathy and detailed investigation of the latter to identify the actual cause remains imperative. Misdiagnosis leading to a wrong surgery caused further deterioration which could have been avoided by careful analysis of imaging. Open surgery remains the preferred treatment for the fistulas supplied by the artery of Adamkiewicz.

Congestive myelopathy (Foix-Alajouanine Syndrome) due to intradural arteriovenous fistula of the filum terminale fed by anterior spinal artery: Case report and review of literature

“…[1] In 1974 Aminoff and Logue hypothesized that in the presence of an AVF there is increased intramedullary venous pressure with resultant decrease of the arteriovenous pressure gradient and concomitant decrease of cord perfusion. [13] Irrespective of the location of the fistula it is the lower part of the cord that is affected commonly and shows signal changes on MRI. Two reasons are put forward to this phenomenon– (a) the intraspinal venous system is valveless and due to gravity the lower part of the cord is more congested and (b) the collateral outflow from the lower part of the dorsal cord is less even in normal subjects[1] and this leads to impaired dissipation of venous hypertension found in patients with AVF's.…”

“…[13] Another cause of the misdiagnosis is the rarity of the condition[2] and has led one study (in the Netherlands) to speculate that a neurologist can expect to see one such case only every 4-8 years. [1] The result is that 40-63% of patients have disease of 1-3 years duration and 10-34% of patients have disease for greater than 3 years by the time they are diagnosed.…”

“…[3] Filum terminale AVF's is a rare variant[56] of intradural AVF's. The filum terminale is supplied by a single feeder that is a continuation of the ASA or a branch descending from the “vascular basket” at the conus.…”

“…[5] conclude that if there is a large distance from the origin of the artery to the fistula site, clipping would be the safer option than embolization. Others[3] too have emphasized on the need for a high index of suspicion to establish diagnosis and hold that surgery is safer with decreased risk of spinal cord ischemia as compared to embolization. [38] Trinh et al .…”

“…Others[3] too have emphasized on the need for a high index of suspicion to establish diagnosis and hold that surgery is safer with decreased risk of spinal cord ischemia as compared to embolization. [38] Trinh et al . [6] have also preferred surgery rather than endovascular treatment in their two cases.…”