Insertion of magnetically controlled growing rods in a patient with a diaphragmatic pacemaker: case report

Phrenic stimulators offer an alternative to standard mechanical ventilation as well as the potential for ventilator independence in select patients with chronic respiratory failure. Young patients (< 10 years old) with high cervical spinal cord injuries often develop paralytic scoliosis due to loss of muscle tone caudal to their spinal cord lesion. Growing rod systems allow for stabilization of spinal deformity while permitting continued growth of the spine and thoracic cavity. Magnetically controlled growing rods (MCGRs) offer the advantage of noninvasive expansion, as opposed to the operative expansion required in traditional growing rod systems. To the authors' knowledge, this is the first reported case of MCGRs in a patient with a diaphragmatic pacemaker (DP). A 7-year-old boy with ventilator dependence after a high cervical spinal cord injury presented to the authors' institution with paralytic scoliosis that progressed to > 120°. The patient had previously undergone insertion of phrenic nerve stimulators for diaphragmatic pacing. The decision was made to insert MCGRs bilaterally to stabilize his deformity, because the planned lengthening surgeries that are necessary with traditional growing rods would be poorly tolerated in this patient. The patient's surgery and postoperative course were uneventful. The DP remained functional after insertion and lengthening of the MCGRs by using the external magnet. The DP had no effect on the expansion capability of the MCGRs. In conclusion, the MCGRs appear to be compatible with the DP. Further studies are needed to validate the long-term safety and compatibility of these 2 devices.