Abstract ID: A32
Abstract Title: pinal Cord Stimulation in a Patient with Implanted Cardioverter-Defibrillator
Authors: GULVE A1, SWARM R2, CHEN J3
WASHINGTON UNIVERSITY SCHOOL OF MEDICINE SAINT LOUIS MO USA1, WASHINGTON UNIVERSITY SCHOOL OF MEDICINE SAINT LOUIS MO USA2, WASHINGTON UNIVERSITY SCHOOL OF MEDICINE SAINT LOUIS MO USA3
Poster Type: Either
ABSTRACT BODY
Introduction
Post-laminectomy radicular pain syndrome is a common indication for spinal cord stimulation. The presence of an automated implantable cardioverter-defibrillator (AICD) or cardiac pacemaker has been considered a relative contraindication to spinal cord stimulation (SCS). We report the successful use of SCS in a patient with AICD.
Case Report
A 68 year-old woman presented with a history of low back pain and right lower extremity neuropathic pain of five years duration. She had undergone L3-S1 laminectomy and L4-5 posterior fusion four years ago without improvement in pain. Four years ago, the patient required Gem®DR 7271 AICD implantation following ventricular fibrillation due to prolonged QT interval secondary to post-viral cardiomyopathy. She suffered from burning pain, radiating from lower back to right lower extremity, in L5 dermatomal distribution. She had marked right lower extremity spasticity and stiffness. She was unable to weight bear and was wheel chair dependent. Our initial attempts at pain management with anticonvulsants, antidepressants, opioids, muscle relaxants and spinal steroid injections failed to relieve pain.
After successful trial of SCS, a permanent SCS system was implanted. Both during SCS trial and subsequent implantation, the following steps were taken to safeguard against possible SCS and AICD interference. The defibrillator was turned off to avoid inadvertent shock. Continuous monitoring of the patient and defibrillator function was performed. A Pisces Z Quad®3890 lead was inserted with tip at the upper border of T8 vertebra. This was connected to Itrel®3 (Medtronic Inc., Minneapolis, USA) pulse generator, set to deliver, amplitude of 2.9V at 50 Hz frequency and pulse width of 450 μs. The AICD was tested for possible interference over a range of various SCS parameters (frequency, pulse width and amplitude). After implant, the SCS patient control device was set to within the tested parameters.
The patient reported significant relief of pain and muscle spasm with SCS, and tapered analgesic and anti-spastic medications. Both from patient-report and review of AICD event log, there has been no SCS interference with the AICD function.
Discussion
Combined use of implantable devices poses the risk of electromagnetic interference. This interference could cause inappropriate delivery of AICD shocks1. SCS artefacts might mask ventricular arrhythmias, resulting in inappropriate inhibition of AICD. AICD shock might change SCS parameters. To minimise interference, only bi- or multi-polar devices with compact electrode spacing should be used. The sensing leads of AICD and stimulator should be spatially separated as far as possible. AICD should be set at the lowest sensitivity. In this case report, we discuss the precautions needed during simultaneous use of SCS & AICD.
Conclusion
We report safe and successful use of SCS for radicular pain in a patient with AICD. There may be a future for combinations of implantable devices in humans. However technical, medical, ethical and medicolegal issues regarding this are still unclear.
Reference
1. Anderson C et al. Management of spinal cord stimulators in patients with implantable cardioverter-defibrillators. Neuromodulation; 5:133-136
ATTACHED FILES
Reg Anesth Pain Med 2005; 30(3):A32