Intraoperative Monitoring for the Lateral Lumbar Interbody Fusion Procedure

Inclusion Criteria:

* At least 18 years of age at the time of planned surgery.
* Indicated for 1- or 2-level instrumented LLIF surgery (in either prone or lateral decubitus positions), inclusive of the L4-5 disc space.
* Written informed consent obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study.

Exclusion Criteria:

* Patients requiring surgical treatment at more than 2 lumbar levels.
* Patients with peripheral neuropathy such as from diabetes or other conditions that might affect the reliability of intraoperative neuromonitoring.
* Patients with prior history of partial/full hip or knee joint replacement surgery (i.e., arthroplasty or resurfacing) on the leg targeted for saphenous monitoring and electrode placement.
* Patients with presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data.
* Female patients who are pregnant or wanting to become pregnant during the timeframe of study participation.
* Patients participating in another clinical study which may compromise this study's results or compliance with this study's procedures.