title: The correlation between cauda equina nerve root volume and sensory block height after spinal anaesthesia with glucose-free bupivacaine.
abstract: We examined the association between cauda equina nerve root volume and sensory block height in 15 patients undergoing spinal anaesthesia with 0.5% glucose-free bupivacaine. Magnetic resonance imaging and a separate image segmentation program were used to calculate the volume of the nerve roots. Nerve root volume was also correlated with lumbosacral cerebrospinal fluid volume and with patients' physical characteristics. Nerve root volume correlated negatively with sensory block height (Spearman rho -0.61 (95% CI -0.85 to -0.14)) and body mass index (Spearman rho -0.66 (95% CI -0.87 to -0.24)) but positively with cerebrospinal fluid volume (Spearman rho 0.76 (95% CI 0.43-0.91)). Factors that are thought to influence cerebrospinal fluid volume, such as body mass index, might similarly affect the volume of the nerve roots. The size of the nerve roots may influence the spread of spinal anaesthesia.
authors.affiliation: Department of Anaesthesia and Pain Medicine, Division of Imaging Services, Royal Perth Hospital, Perth, WA, Australia. john.martyr@health.wa.gov.au
authors.forename: J W
authors.initials: JW
authors.lastname: Martyr
authors.forename: S J
authors.initials: SJ
authors.lastname: Song
authors.forename: J
authors.initials: J
authors.lastname: Hua
authors.forename: S
authors.initials: S
authors.lastname: Burrows
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D015992:Body Mass Index; D002045:Bupivacaine / Q000008:administration & dosage*; D002420:Cauda Equina / Q000473:pathology*; D002555:Cerebrospinal Fluid / Q000502:physiology; D005947:Glucose; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012677:Sensation / Q000187:drug effects / Q000502:physiology; D020728:Transurethral Resection of Prostate
chemical_list: D000779:Anesthetics, Local; D005947:Glucose; D002045:Bupivacaine