NEONATAL SOCIETY ABSTRACTS
Sonographic determination of spinal canal depth in neonates
Presented at the Neonatal Society 2001 Summer Meeting (programme).
Zubier M, Kelsall W, Tooley J
Neonatal Intensive Care Unit, Rosie Maternity Hospital, Cambridge, UK
Background: The assessment of suspected neonatal infections may require analysis of cerebrospinal fluid (CSF) (1). Up to 50% of CSF samples obtained from newborns can be blood stained and difficult to interpret (2). Traumatic blood stained samples are usually due to damage to the venous plexus on the posterior vertebral bodies, when the lumbar puncture (LP) needle is inserted too far. A normogram has been developed for LP needle insertion in children based on height (3).
Objective: To use ultrasound to measure the depth of the spinal canal (S.C) below
the skin, to construct a normogram for LP needle insertion in relation to weight
Methods Infants were recruited in the study following admission to the neonatal unit and transitional care wards. After written consent, ultrasound measurements were made with the infant positioned in the curled left lateral position as for LP at the site between L3- L4. Ultrasound scans were performed by 2 investigators using a 6 MHz phase array probe -Toshiba Powervision scanner. Images were frozen and 3 measurements were performed (1) skin to superficial wall of S.C, (2) skin to deep wall of SC and (3) mid point of S.C
Result: Scans were performed on 116 newborn infants, median gestational age 34
weeks with range of (24- 42 weeks),and median birth weight 2461grams with range
of ( 520- 4610 grams).
Results of spinal canal depth against weight are shown below, the correlation of mid point of spinal canal r = 0.922
Conclusion: There is a clear relationship between weight and spinal canal depth. Use of the normogram could reduce the number of traumatic LP.
1. Hristeva L, Bowler I, Booy R, King AT, Wilkinson AR 1993 Value of CSF Examination in the diagnosis of meningitis in the newborn. Archives of diseases in Childhood 69: 514-517
2. Bazimo JM, Krim G, Kremp O, Leke L 1995 Retrospective analysis of 1331 samples of cerebrospinal fluid in newborn infants with suspected infection Arch Pediatr 2(9) : 833-839
3. Craig F, Stroobant J, Winrow A, Davies H. 1997 Depth of insertion of a lumbar puncture needle. Archives of Disease in Childhood 77(5): 450