Dural sac localization using myelography and its application to the lumbosacral epidural in dogs

Abstract

Background: The techniques described for the identification of the lumbosacral (LS) epidural space in dogs do not guarantee the needle position or an accidental subarachnoid puncture, especially in small size dogs.Aim: To determine the relationship between body weight and the location of the dural sac (DS) using myelography in dogs, and to determine the possibility of subarachnoid puncture during LS epidural based on the position of the DS.Methods: Four masked observers evaluated 70 myelographic studies of dogs, annotating the vertebrae where the DS ended, if it was localized before or after the LS space, and if accidental subarachnoid puncture during LS epidural injection was possible (yes/no). Body weight (kg) was categorized into: less than 10 kg, between 10 and 20 kg, and more than 20 kg and was also converted to body surface area (BSA) as a continuous variable.Results: The DS ended at the LS space or caudally in 50% of dogs. There was a statistically significant difference between the position of the DS and the dog’s BSA (p = 0.001). The DS ended caudal to the LS space in 72.7% of dogs weighing <10 kg, in 25% of dogs between 10 and 20 kg and in 15% of dogs in the >20 kg category. The observers considered a possible subarachnoid puncture during LS epidural in 69.7% of patients <10 kg, 16.6% on those between 10 and 20 kg, and in 11.7% of the dogs >20 kg.Conclusion: The DS ended caudal to the LS space in almost 3/4 dogs in the <10 kg category, so accidental subarachnoid puncture during LS epidural is highly possible in this weight range.

Onset of Action of Bupivacaine Administered via Dural Puncture Epidural versus Spinal, Lumbosacral, and Sacrococcygeal Epidural Injections in Dogs: Randomised Clinical Trial

“…For instance, Lang and Marin-Garcia et al reported the end of the dural sac at the level of the first-second and second-third sacral vertebrae in medium to large dog breeds and German Shepherd dogs, respectively [7,29]. Zapata et al reported the termination of the dural sac caudal to the lumbosacral intervertebral space in more than 50% of all dogs studied with myelography and in more than 75% of small dogs (<10 kg) [30]. When scrutinising magnetic resonance images of a multitude of dogs a various breeds and sizes, Khan et al found that the most common dural sac termination in dogs was in the cranial half of the sacrum, irrespective of bodyweight or spinal cord length [31].…”

“…When scrutinising magnetic resonance images of a multitude of dogs a various breeds and sizes, Khan et al found that the most common dural sac termination in dogs was in the cranial half of the sacrum, irrespective of bodyweight or spinal cord length [31]. Regardless of the exact point at which the dural sac ends, the presence of this sac was evident at the lumbosacral intervertebral space in a great number of dogs of various sizes and breeds, to the point that some of these authors warned the reader about the risk of performing a subarachnoid puncture when attempting an epidural injection [30].…”

Computed Tomography-Derived Occipital–Coccygeal Length and Ilium Wing Distance Correlates with Skin to Epidural and Intrathecal Depths in Dogs

“…The main interest of this study was to correlate external morphometric variables with depth variables. It is reasonable to think that these morphometric variables capture at least some of the breed conformations variations [28][29][30][31]. Any attempt to stratify the results by breed would have resulted in extremely underpowered results.…”

Computed Tomography Assessment of the Conus Medullaris and the Dural Sac Termination in Adult Sheep: Anatomical Implications for Lumbosacral and Sacrococcygeal Injections

“…Studies have focused on determining the vertebral level and variations in the conus medullaris and dural sac position to enhance clinical relevance and procedural safety [18,19]. While the anatomy, extent and variations of some species' conus medullaris and dural sacs, such as those of cats [20] and dogs [18, 21,22], are well documented, information speci c to sheep is limited. Computed tomography has been used to study the spine, vertebrae and dural sac in sheep [23] and dogs [22].…”

“…While the anatomy, extent and variations of some species' conus medullaris and dural sacs, such as those of cats [20] and dogs [18, 21,22], are well documented, information speci c to sheep is limited. Computed tomography has been used to study the spine, vertebrae and dural sac in sheep [23] and dogs [22]. This study addresses this gap by comprehensively describing the relationship between the conus medullaris and dural sac in adult sheep's lumbosacral and sacrococcygeal spaces, lling a crucial void in the literature.…”