TYPICAL SI FUSION PATIENT… SYMPTOMS: Low back pain Buttock and hip pain Ipsilateral LE weakness LE numbness and tingling Trouble sleeping Leg instability Problems sitting
SI JOINT AS A CAUSE OF PAIN: 25% of all low back pain is caused by Sacroiliac joint disease. The incidence of SI joint degeneration in post-lumbar fusion surgery is 75% at 5 years post-op. SI joint is a pain generator in low back pain of 43% post- lumbar and lumbar-sacral fusion patients.
Clinical tests Imaging studies (x-ray. CT scan, MRI) SI joint injections of a local anesthetic DIAGNOSIS…
Alarm Criteria: -Amplitude decrease of 50% -Latency increase of 10% SSEP
EXAMPLES OF CHANGES
Patient had LUE amplitude decrease of greater than 50% due to a positional issue.
Needle electrodes used in the following muscles: L5- Tibialis Anterior S1- Gastrocnemius S2- Anal Sphincter EMG
Alarm Criteria: Any burst/firing from nerves on the side the surgeon is working. FREE RUN EMG
Stimulation probe used to stimulate either the guide wire/pin or the drill bit to insure a safe distance between the drill bit and the neural structures. SE-EMG
Alarm Criteria: Response <8 mA with an absolute minimum of 6 mA SE-EMG
LE numbness LE weakness Incontinence Foot drop IN THE CASE OF NERVE INJURY
REFERENCES -"Minimally Invasive Sacroiliac Joint Surgery." MIS Sacroiliac Joint Fusion Surgery. SI-BONE, n.d. Web. 08 Apr Moed, B.R. (2008). Monitoring neural function during pelvic surgery. In M.R. Nuwer (Ed.), Intraoperative Monitoring of Neural Function Handbook of Clinical Neurophysiology (vol. 8, pp ). Elsevier B. V. -Moore MD, M.R. (2012, January ). The Sacroiliac Joint: A Forgotten Pain Generator. The SI-BONE Sentinel, 1-2.