Today’s Pediatric Anesthesia Article of the Day is an excerpt of a keyword summary on myelomeningocele from Open Anesthesia www.openanesthesia.org that will be published soon. This is a supplement to yesterday’s PAAD on the medical and neurosurgical management of Spina Bifida. Unlike the previous article, today’s PAAD discusses the anesthetic considerations for the postnatal surgical repair of this medical malformation. Myron Yaster MD
Original article
Myelomeningocele coming soon on Open Anesthesia
Postnatal Care
· Following prenatal diagnosis, the patient should be referred to a center with a multi-disciplinary team of specialists for counseling and delivery planning. There is no consensus on the preferred method of delivery.
· After stabilization in the delivery room, the newborn must be positioned in the prone or lateral position to avoid pressure on the MMC lesion. A sterile, saline-soaked gauze should be used to cover the lesion, and prophylactic antibiotics should be started.
· Latex precautions must be instituted from birth.
· Surgical closure should be performed within 72 hours after birth. Following surgical closure, the progression of hydrocephalus must be closely monitored, and some infants may need ventriculoperitoneal shunting.
Anesthetic Considerations for Postnatal Surgical Repair
Preoperative Investigations
· Complete blood cell count for baseline and type and crossmatch for surgery.
· Basic metabolic profile to rule out electrolyte abnormalities or dehydration from large lesions.
· Cranial ultrasound to assess the extent of ventriculomegaly and hydrocephalus.
· Renal ultrasound to rule out genitourinary abnormalities.
Intraoperative and Postoperative Care
· Continue latex precautions.
· Most centers perform the surgical repair under general endotracheal anesthesia. However, the safe use of spinal anesthesia with hyperbaric 0.5% tetracaine with epinephrine injected into the caudal end of lumbar myelomeningoceles in a case series of 14 neonates has been described.1
· During induction, avoid direct pressure on the MMC lesion by using sterile towels and sterile towel covered head (donut) rings to support the infant’s back. Alternatively, the infant may be positioned in the lateral decubitus position for induction and intubation.
· Standard ASA monitors, including temperature monitoring, must be used. Arterial and central lines are rarely used. Blood loss can be considerable for larger lesions, and appropriate intravenous access should be obtained.
· Surgical repair is performed in the prone position, and the infant must be appropriately positioned and padded.
· Postoperative ventilation in the prone position for 1-3 days is not uncommon.
From Myron: This is an urgent and not an emergent procedure. Lab work, particularly a type and cross is to my mind really overkill. Most of these children arrive with an IV, or one can easily be placed awake in an insensate, lower extremity site. Further, a really cool trick is to draw up 0.3-0.5 mL of spinal bupivacaine or tetracaine in a sterile fashion. Once the meningocele is exposed, either you or the surgeon can squirt the local anesthetic into the exposed filum terminale of the spinal cord and CSF. This will provide most of the anesthesia for the surgical procedure. Finally, the Vermont school of spinal anesthesia used only spinal anesthesia and no general anesthesia for this surgical repair.1, 2
References
1. Viscomi CM, Abajian JC, Wald SL, Rathmell JP, Wilson JT. Spinal anesthesia for repair of meningomyelocele in neonates. Anesthesia and analgesia. Sep 1995;81(3):492-5. doi:10.1097/00000539-199509000-00011
2. Abajian JC, Mellish RW, Browne AF, Perkins FM, Lambert DH, Mazuzan JE, Jr. Spinal anesthesia for surgery in the high-risk infant. Anesthesia and analgesia. Mar 1984;63(3):359-62.