P047: SPINAL CORD STIMULATOR LEAD INSERTION COMPLICATED BY PREEXISTING BONE GROWTH STIMULATOR
Esther Ogunyemi, MD; Brittany Ahuja; William Grubb; Rutgers - Robert Wood Johnson Medical School
Introduction: Epidural lead placement for spinal cord stimulation (SCS) is an important skill for an interventional pain physician. Entry point and angle of the Tuohy needle often determine the ease and success of lead insertion. However, patient anatomy and presence of hardware could make for a difficult procedure1. We present a case in which the placement of epidural SCS leads was made more challenging by attempts to avoid a previously implanted, non-functional bone growth stimulator.
Methods: A 56yo male with multiple comorbidities presented to our pain clinic for evaluation and management of chronic lower back pain. Patient has a longstanding history of back pain that began in 1994 following a motor vehicle accident. He is s/p lumbar discectomies and fusion with subsequent bone growth stimulator (BGS) implant to improve the outcome of his multi-level spinal fusion. Patient endorses midline lower back pain that radiates bilaterally to his feet. Multiple epidural injections and medication adjustments provided poor pain relief. The decision was made for SCS trial to assess his response to neuromodulation.
Preoperative imaging demonstrated a BGS generator in the left L2 paraspinal soft tissues with two electrodes arising from its inferior border. We decided we could potentially circumvent the generator and leads by attempting needle entry at L1.
Informed consent was obtained and the patient was placed on the operating table in a prone position with all pressure points supported. Sedation and antibiotics were administered by an anesthesiologist. After sterile preparation, the T12-L1 interlaminar space was identified using AP fluoroscopy. Using a 25-gauge 1-1/2 inch needle, 5 mL of 1% lidocaine with epinephrine was injected 2 cm right and left of the midline below the L1 pedicle. Steep entry of the 14-gauge Tuohy epidural needle was crucial in avoiding the patient's preexisting BGS in the L2 paraspinal muscle. The needle was advanced in the paramedian approach under lateral fluoroscopy until loss of resistance to air was achieved in the T12-L1 epidural space. The leads were advanced to the superior aspect of T8 vertebral body, positioned slightly left and right of midline. Final position of leads was verified in AP and lateral views.
Results: The patient endorsed improvement in ADLs and > 75% pain relief during his 3-day SCS trial. He is enthusiastic about permanent implantation of SCS device. Plan is to refer to neurosurgery for evaluation and possible removal of BGS device prior to SCS implant.
Discussion: A hallmark of a skilled interventionalist is the ability to adapt to unexpected intraoperative challenges. Our patient presented with a history of both multilevel lumbar spinal fusion and an inactivate BGS in the left L2 paraspinal soft tissues. These conditions are known to cultivate challenging alterations in epidural access. Our technique of inserting the Tuohy needle steeply in the paramedian approach allowed us to safely enter the epidural space under fluoroscopy until loss of resistance was obtained.
1. Zhu J, Falco F, Onyewu O, Josephson Y, Vesga R, Jari, R. Alternative Approach To Needle Placement In Spinal Cord Stimulator Trial/Implantation. Pain Physician 2011; 14:45-53