Published in A&A Case Reports 15 December 2014 – Volume 3 – Issue 12 – p 157–159
Authors: King, Michael R. MD; Anderson, T. Anthony PhD, MD
From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts.
We describe using ultrasound-guided peripheral nerve blocks for postoperative pain control in 2 children undergoing ventricular shunt surgery. In the first patient undergoing ventriculo-peritoneal shunt revision, a combination of ultrasound-guided greater occipital nerve, superficial cervical plexus, and transversus abdominis plane blocks was used. In the second patient undergoing ventriculo-pleural shunt revision, a combination of ultrasound-guided greater occipital nerve, superficial cervical plexus, and intercostal blocks was used. Both patients, who underwent multiple revisions during their hospitalizations, showed decreased analgesic requirements after regional anesthesia. Our experience suggests this combined block technique may provide beneficial postoperative analgesia for patients undergoing shunt revision.
The use of peripheral nerve blocks, including greater occipital nerve and superficial cervical plexus blocks, has been described for patients undergoing ventriculo-peritoneal (VP) shunt placement or revision as well as other head and neck surgeries.1–4 Although these 2 blocks are effective for analgesia at the cephalic incision and tracking sites, they provide no pain relief for the abdominal incision site or, in the case of a ventriculo-pleural (VPL) shunt, the thoracic incision site. Pain at these 2 sites can, however, be treated by other blocks that are familiar to most anesthesiologists: The transversus abdominis plane (TAP) block, which provides effective pain control and decreases opioid requirements after a variety of abdominal surgeries in infants and children,5 and the intercostal nerve block, an established regional technique in patients undergoing thoracic surgery.6 We present 2 cases of successful postoperative pain relief for ventricular shunt revision using novel combinations of peripheral nerve blocks that have not been previously
described.
Written, informed consent for the procedures was obtained from the mothers of both patients. The patients gave assent and the mothers gave written consent to have the details of their cases shared in this report. Our institution’s IRB does not require review of case reports.
CASE DESCRIPTION
Case 1
A 13-year-old, 38-kg male with a history of tuberous sclerosis and developmental delay diagnosed with an enlarging left lateral ventricular giant cell tumor underwent successful tumor debulking but developed hydrocephalus and subsequently underwent VP shunt placement on postoperative day 12. The placement was complicated by postoperative pain requiring 0.1 mg/kg of morphine every 3 hours for the first 12 hours postoperatively (Table 1). Because of the repeated malfunction of the VP shunts, the patient required 3 subsequent revisions. For the first revision, despite intraoperative IV morphine, the patient again had significant postoperative pain, requiring 0.05 mg/kg of morphine approximately every 2 hours for the first 18 hours postoperatively (Table 1). Given his prior discomfort and opioid requirements, we offered a regional adjunct to treat pain associated with the occipital, neck, and abdominal dissection and incision sites for the second revision.
After induction of general anesthesia and tracheal intubation, the right occipital nerve was identified under ultrasound guidance. Five milliliters 0.5% ropivacaine was deposited around the occipital nerve. Ten milliliters 0.5% ropivacaine was deposited superficially along the posterior border of the right sternocleidomastoid muscle. Just before emergence, the external oblique, internal oblique, and transversus abdominis muscles were identified as described previously7 using ultrasound guidance and a total of 10 mL 0.2% ropivacaine was injected between the internal oblique and transversus abdominis. Emergence from anesthesia was smooth and the patient arrived in the intensive care unit comfortable despite minimal use of opioids intraoperatively. Per the patient’s mother, the occipital block lasted 12 hours while the TAP block lasted 18 hours and no opioids were required overnight. He received 2 doses of oral acetaminophen, which he had been taking every 6 hours throughout his hospitalization, and 2 doses of ketorolac given more than 6 hours after surgery. The decision to use ketorolac instead of opioids was made independently by the intensive care unit team. Despite being largely pain-free for 16 hours postoperatively per the patient’s mother, the patient developed anxiety that was treated with lorazepam. The patient’s mother identified the source of the patient’s anxiety as persistent numbness over his right occiput. Nonetheless, the patient’s mother was very satisfied with the degree of pain control. The patient required 1 last shunt revision the next week and was managed with IV pain medications without regional adjunct, experiencing significant postoperative pain.
Case 2
A 2-year-old, 9-kg male with a recently diagnosed astrocytoma was admitted for VP shunt placement after the development of hydrocephalus. However, the patient experienced immediate postoperative pain requiring IV morphine administration in the postanesthesia care unit. Forty-three days later, the patient required readmission for hydrocephalus and underwent revision of his VP shunt, again with immediate postoperative pain requiring morphine. On the 46th postoperative day, the patient again required revision, this time converting his VP to a VPL shunt due to concern related to abdominal infection. Given his prior postoperative pain issues, we offered regional adjunct.
After induction of general anesthesia and tracheal intubation, the VPL shunt revision was completed. Under ultrasound guidance, 2 mL 0.2% ropivacaine plus 3 micrograms clonidine were deposited around the right occipital nerve, 4 mL 0.2% ropivacaine plus 3 micrograms clonidine were deposited superficially along the posterior border of the right sternocleidomastoid muscle, and 2 mL 0.2% ropivacaine was deposited along the inferior portion of ribs 2 and 3 each along with 3 micrograms of clonidine (total of 10 mL 0.2% ropivacaine and 9 micrograms clonidine). Despite receiving no morphine intraoperatively, the patient experienced improved pain control postoperatively, requiring no IV analgesics and received only a single dose of ibuprofen 5 mg/kg per os in the postanesthesia care unit. His mother reported excellent pain control for 12 hours during which he only received oral acetaminophen, which he had also received after the prior surgeries.
DISCUSSION
Combining greater occipital nerve and superficial cervical plexus blocks with TAP or intercostal blocks is a novel method for postoperative pain control in patients undergoing ventricular shunt placement and revision. Each block can be facilitated with ultrasound guidance if one learns to identify the normal anatomy. Using these blocks may be helpful for reducing analgesic requirements in patients undergoing shunt procedures and in turn facilitating neurologic status examinations. In addition, decreased opioid use may reduce the incidence of postoperative nausea and vomiting, which can be confused as symptoms of increased intracranial pressure and lead to unnecessary diagnostic workups. In the pediatric population, it can be difficult to assess pain scores accurately.8 As we perform more of these blocks for patients undergoing ventricular shunt procedures, we anticipate formally assessing the data necessary to characterize postoperative opioid utilization.
The use of regional anesthesia in pediatric patients with in situ shunts as well as those undergoing shunt placement or revision is sparsely described in the literature. Previous reports on regional anesthesia in pediatric patients with in situ shunts are limited but suggest that most techniques can be performed safely. Small case series evaluating caudal9 and spinal10 anesthesia for abdominal and orthopedic procedures in pediatric patients with VP shunts reported effective analgesia without complications. Reports of ultrasound-guided peripheral nerve blocks of the head and neck for patients with indwelling shunts are limited to a case report of a successful ultrasound-guided interscalene block in an adult.11 Although head and neck blocks for VP shunt procedures are recognized techniques and have been described in a pediatric regional anesthesia review,1 the literature currently lacks a report investigating the efficacy of regional adjuncts for shunt placement or revision. Postoperative analgesia is usually limited to nonsteroidal antiinflammatory drugs, acetaminophen, and opioids in most centers. Before the advent of ultrasound technology, peripheral nerve blocks in the head and neck were performed without direct visualization and exposed the patient to the risk of infection or puncture of the shunt. These complications could result in subsequent shunt malfunction, pneumocephalus, or local anesthetic injection into the cerebrospinal fluid. It is likely that these risks slowed the development of peripheral nerve blocks for shunt procedures. Although these risks are not eliminated with the use of ultrasound, block placement in the area of a shunt should not pose a significantly greater risk as long as sterile technique is observed and the shunt and needle are visualized with ultrasound throughout the entire placement of the block. As more pediatric anesthesiologists become comfortable with ultrasound-guided regional anesthesia, we are optimistic that more practitioner experience will clarify the risk/benefit profile of regional adjuncts in children undergoing shunt procedures.
An unfortunate side effect of the block in patient no. 1 was anxiety when he awoke unable to feel half of his head due to the superficial cervical plexus and cervical blocks. Although regional anesthesia is not necessarily contraindicated in patients with developmental delay, there is the potential for the child to misinterpret the nerve block and should be considered when selecting candidates.
In summary, we present the combination of greater occipital nerve, superficial cervical plexus, and either TAP or intercostal blockade as a novel regional technique for postoperative pain control in individuals undergoing VP and VPL shunt revision. In both patients, a decrease in IV analgesic requirement and improved pain control occurred. On the basis of our limited experience with this technique, we suggest the need for additional prospective studies to more completely define the advantages and limitations of regional blocks in this population of surgical patients.
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