Retrospective case series from a multicenter database.
To evaluate the risk of neurologic injury during growing rod surgeries and to determine whether intraoperative neuromonitoring is necessary for all growing rod procedures.
Although the use of growing rod constructs for early-onset spinal deformity has become a commonly accepted treatment, the incidence of neurologic events during growing rod surgeries remains unknown.
We reviewed data from a multicenter database on 782 growing rod surgeries performed in 252 patients. VEPTR devices and any constructs with rib attachments were excluded. A questionnaire was sent to all surgeons contributing cases requesting detailed information about all neurologic events associated with any growing rod surgery.
There were 782 growing rod surgeries performed on 252 patients including 252 primary growing rod implantations, 168 implant exchanges, and 362 lengthenings. Five hundred sixty-nine of 782 (73%) cases were performed with neuromonitoring. Only one clinical injury occurred in the series, resulting in an injury rate of 0.1% (1/782). This deficit occurred during an implant exchange while attempting pedicle screw placement, and resolved within 3 months. There were 2 cases with neuromonitoring changes during primary implant surgeries (0.9%, 2/231), 1 change during implant exchanges (0.9%, 1/116), and 1 neuromonitoring change during lengthenings (0.5%, 1/222). The single monitoring change that occurred during a lengthening was in a child with an intracanal tumor who also had a monitoring change during the primary surgery. There are anecdotal cases (outside this study group series) of neuromonitoring changes during simple lengthenings in children with uneventful primary implantations.
Based on our study, the largest reported series of growing rod surgeries, the rate of neuromonitoring changes during primary growing rod implantation (0.9%) and exchange (0.9%) justifies the use of intraoperative neuromonitoring during these surgeries. As there were no neurologic events in 361 lengthenings in patients with no previous neurologic events, the question may be raised as to whether intraoperative neuromonitoring is necessary for simple lengthenings in these patients. However, caution should be maintained when interpreting our results as anecdotal cases of neurologic changes from simple lengthenings do exist outside of this series.
In a series of 782 growing rod surgeries, there were no permanent neurologic deficits and a 0.1% rate of transient neurologic injury. The incidence of neuromonitoring changes during primary implantation (0.9%), implant exchanges (0.9%), and lengthenings (0.5%) was low. As there were no neurologic events in 361 lengthenings in patients with no previous events, intraoperative neuromonitoring may not be necessary for lengthenings in these children.
From the Division of Orthopaedic Surgery, Children's Hospital Los Angeles, Los Angeles, CA.
Acknowledgment date: April 25, 2008. Revision date: August 31, 2008. Acceptance date: September 2, 2008.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
This is an IRB-approved study.
Address correspondence and reprint requests to David L. Skaggs, MD, Division of Orthopaedic Surgery, Children's Hospital Los Angeles, 4650 Sunset Boulevard 69, Los Angeles, CA; E-mail: DSkaggs@chla.usc.edu