Intrathecal Morphine in the Presence of a Syrinx in Pediatric Spinal Deformity Surgery.

BACKGROUND

Intrathecal morphine (IM) is a popular adjunct for pain relief during pediatric spinal deformity surgery. There is no literature regarding its usefulness and safety in the presence of a spinal cord syrinx for patients undergoing spinal instrumentation. Anesthesiologists have previously been reluctant to use IM in the presence of any syrinx.

METHODS

We retrospectively reviewed all patients with a preoperatively diagnosed spinal cord syrinx undergoing spinal deformity surgery who received IM and did not receive IM (non-IM). We recorded location of the syrinx, surgical time, length of stay, unexpected pediatric intensive care unit (PICU) admission, IM related complications (neurological, respiratory depression, or pruritus, nausea/vomiting), and reason for no IM administration. Patients with a syrinx and myelodysplasia (8), tethered spinal cord (4), paraplegia (1), holocord (1), neuroblastoma (1), and spinal cord glioma (1) were not given IM. Other reasons included a failed attempt (1), expectedly short surgical time (1), and anesthesiologist declined (2).

RESULTS

There were 42 patients who met the inclusion criteria. Twenty-two patients received IM, while 20 patients did not. Patients receiving IM had 4 cervical, 5 cervicothoracic, 12 thoracic syrinxes, and 1 holocord syrinx. The non-IM group had 8 cervicothoracic, 6 thoracic, 4 holocord syrinxes, and 2 had unclassified locations. There were no neurological complications in the IM group, and 1 patient experienced respiratory depression following a shorter than expected surgery and was observed overnight in the PICU. One patient in the non-IM group with a holocord syrinx had temporary lower extremity weakness postoperatively that completely resolved and 4 patients were unexpectedly admitted to the PICU. Pruritus and nausea/vomiting was mild and similar in both groups.

CONCLUSIONS

Our study demonstrates that with careful preoperative evaluation, most patients with a spinal cord syrinx can safely be given IM. Certain patients, such as those with a spinal holocord syrinx may have anatomic reasons to avoid IM, but those who are deemed appropriate for IM can receive it safely.

LEVEL OF EVIDENCE: Level III-therapeutic study; retrospective comparative study.