Spontaneous Spinal CSF Leaks Stratified by Age, Body Mass Index, and Spinal Level

Abstract

BACKGROUND AND PURPOSE: There are 3 main types of spinal CSF leaks, and the imaging appearances are well-reported. Specific patient demographics and spinal locations of the various types of spinal leaks are less frequently described. The purpose of this article was to stratify the various types of spontaneous CSF leaks on the basis of age, body mass index, and spinal level. MATERIALS AND METHODS:Retrospective review was performed for all patients with spontaneous spinal CSF leaks identified on CT myelography. Age, body mass index, and spinal CSF leak type and level were recorded.RESULTS: Sixty-five patients (37 women and 28 men) had spinal CSF leaks. Type 1 CSF leaks (dural tears) were observed in 25 patients (mean age, 44.5 years; mean body mass index, 24.3) and were most common in the upper thoracic spine (72%), particularly at the T1-T2 level (36%). Type 2 CSF leaks (ruptured meningeal diverticula) were observed in 4 patients (mean age, 45.5 years; mean body mass index, 27.5) and were all seen in the lower thoracic spine. Type 3 CSF leaks (CSF-venous fistulas) were observed in 36 patients (mean age, 58.8 years; mean body mass index, 27.0) and were most common on the right side (72%) and in the lower thoracic spine (56%).CONCLUSIONS: Type 1 CSF leaks occurred in younger patients with a normal body mass index, while patients with type 3 CSF leaks were relatively older and had an elevated body mass index. Type 1 leaks mostly occurred in the upper thoracic spine, and types 2 and 3 leaks mostly occurred in the lower thoracic spine.ABBREVIATIONS: BMI ¼ body mass index; CTM ¼ CT myelography; CVF ¼ CSF-venous fistula; SIH ¼ spontaneous intracranial hypotension; W ¼ Shapiro-Wilk test statistic S pontaneous intracranial hypotension (SIH) is typically secondary to a spinal CSF leak, and there are 3 main types: dural tears (type 1), ruptured meningeal diverticula (type 2), and CSFvenous fistulas (type 3). 1 In the past several years, our awareness and detection of these spinal CSF leaks have increased secondary to novel techniques such as dynamic prone myelography for dural tears and decubitus myelography for ruptured meningeal diverticula and CSF-venous fistulas (CVFs). [2][3][4] Despite these advancements, there are many unanswered questions, including why spontaneous CSF leaks occur and in

Prevalence of SLEC-negative spontaneous intracranial hypotension in patients with spinal nerve root sleeve diverticula on MRI

“…While spinal NRD are thought to be associated with some Type 2 and nearly all Type 3 leaks in SLEC-negative SIH, [1][2][3] the overall prevalence of SIH in patients with these cysts is unknown. This is an important consideration given that perineural NRD are often a non-clinically significant and incidental finding in otherwise healthy patients.…”

“…SLEC-negative Type 2 leaks are thought to occur secondary to either distal nerve root sleeve tears or ruptured distal meningeal diverticula. 1,2 Similarly, Type 3 leaks caused by CSFVF have recently emerged as an important cause of SIH with previous studies suggesting that the majority (up to 82%) of CSFVF originate from a NRD where CSF abnormally flows into a venous channel adjacent to the nerve root sleeve. 3,4 However, despite the apparent association between NRD and Type 2 and 3 leaks, spinal diverticulae are often an incidental finding with no clinical significance.…”

Spontaneous Intracranial Hypotension: A Review of Neuroimaging and Current Concepts

“…It occurs frequently in middle aged females with lesser or normal resting metabolic rate, although the incidence in men is not very uncommon in recent times. 10,12 Type 2 leaks are classified further as spinal longitudinal epidural collection positive (SLEC-P) which means there is definite spinal longitudinal epidural collection and SLEC negative (SLEC-N) where there is no epidural collection. SLEC-P type 2A leaks occur due to lateral dural tear wherein nerve root sleeve tear occurs proximally with positive SLEC.…”

“…9 CVFs are more commonly seen along the lower thoracic spine and in elderly. 12 They may be associated with meningeal diverticulum that is seen as perineural cyst. Such cysts may give rise to CVFs acting as a nidus.…”

Modified Dynamic CT Myelography for Type 1 and 2 CSF Leaks: A Procedural Approach

“…The dynamic CTM technique has the major advantage in identifying a calcified disc, which is very commonly seen with type 1 CSF leaks and is often small and located in the upper thoracic spine. 9 In fact, because of the high spatial resolution of CT, a postmyelography CT is performed after DSM or conventional fluoroscopic myelography for disc detection and treatment planning. 7,8 One major limitation for dynamic CTM is the radiation dose because multiple scans of the spine, reported up to 10 times, 5 are performed consecutively to ensure a high temporal resolution and to identify the leak location.…”