Are Lumbar-Peritoneal shunts a contra-indication to Epidural anesthesia in the age of the Ultrasound?
Subramanian H, Sherdiwala B, Walton L. Are Lumbar-Peritoneal shunts a contra-indication to Epidural anesthesia in the age of the Ultrasound?. Regional Anesthesia and Pain Medicine 2017; 42(6).
Regional Anesthesia and Pain Medicine
Introduction Lumbar-peritoneal shunts are placed to reduce the intra cranial pressure (ICP) in patients with increased ICP caused by a number of reasons. These shunts present a challenge to the anesthesiologist and many tend to avoid neuraxial anesthesia due to concern of damage to the shunt, altered epidural anatomy and faster CSF turnover. But with Ultrasonographic (USG) assistance Epidural/Intrathecal catheters can be placed successfully and general anesthesia can be avoided. Results/Case report A 32 year old mother (BMI 28) with a Gravidity of 4 and a Parity of 2 at 39 weeks of gestation who presented to our OB service to undergo an elective C-Section in view of previous 2 C-sections. PMH was significant for Hypothyroidism and Bacterial Meningitis at the age of 17 complicated by hydrocephalus and raised ICP. She had a Ventriculoperitoneal (VP) shunt placed initially and a Lumbar-Peritoneal (LP) shunt 10 years ago, when the VP shunt failed. She Denied any symptoms of Increased ICP since. On examination of the back, the LP shunt was palpable from the L3-L4 Space via the subcutaneous tissue and anteriorly to the abdominal wall. Confirmation of the Shunt insertion into the L3-L4 space was done using an ultrasound and the course marked on the skin. Normal anatomy of the L1-L2 as well as the L2-L3 intervertebral space was noted. An Epidural catheter was placed at the midline in the L1-L2 Space and tested with Lidocaine which resulted in a bilateral dense T6 level Block. Patient was taken up for C-section and required a total of 25 ml of Lidocaine through the procedure. Post-operative course and catheter removal were unremarkable. Discussion The suspected complications of epidural placement in the presence of a LP shunt are damage to the shunt, difficult access to epidural space due to scarring or altered anatomy, rapid clearance of the anesthetic and rare theoretical complications like knotting of the epidural. These concerns expose more patients to the elevated risks of general anesthesia, especially in Obstetrics. The three reports of neuraxial anesthesia for Laboring patients with LP shunts, were described prior to 2002, before the widespread availability of USG . USG has shown to reduce the number of attempts, failed epidurals and accidental dural puncture. We propose that by identifying the LP shunt as well as a normal intervertebral space anatomy on USG the the risk of puncturing the shunt is also minimized. Re-dosing of the epidural anesthesia may be required  which may be done incrementally. All three of these reports as well as our own experience seem to indicate that neuraxial anesthesia may very well be a safe option today for our patients with LP shunts.