The routine intra-operative use of pulse oximetry for monitoring can prevent severe thromboembolic complications in anterior surgery.

Introduction: Anterior access to the lumbar spine is established for disc replacement surgery and anterior interbody fusion in the lumbar spine. The spine is accessed normally from the left side either by a transperitoneal or retroperitoneal approach through a midline or oblique skin incision. After reaching the retroperitoneum and depending on the level of exposure, the surgeon has to mobilise and retract the aorta or left common iliac artery, as well as the left common iliac vein or internal vena cava to the right lateral border to address the whole disc space. The left common iliac artery is especially stretched during intervertebral disc exposure putting it at a greater risk of adverse events. Not surprisingly, vascular adverse events like direct injuries, thrombosis and embolism are feared complications in anterior surgery. Permanent intra-operative left leg oxygen saturation surveillance via pulse oximetry can help detecting embolic situations thereby allowing immediate treatment minimising the leg ischemia or preventing limb loss.
Case Report: In the presented case, a 61-year-old male patient undergoing a two-level anterior interbody fusion lost oxygen saturation in the left leg after vessel retraction for exposure. After cage insertion and release of the retractor blades, the pulse oximetry signal did not return and no pulses were found during instant Doppler investigation below the femoral artery, indicating severe embolism in the left leg. The left common iliac artery was clamped and opened showing a ruptured calcified plaque with adherent fresh thrombotic material. An endovascular embolectomy in the superficial and deep femoral artery revealed several small thrombi. An artherectomy of the common iliac artery followed by patch closure was performed. Immediately after clamp release, pulse oximetry returned and Doppler signals were detectable at the tibialis posterior and dorsalis pedis artery. Post-operative recovery was uneventful and pulses were palpable at all times.
Conclusion: Arterial adverse events in anterior access surgery are rare complications but none the less, it is of paramount importance to detect and treat these situations immediately. This case highlights the need of routine pulse monitoring during the whole anterior surgery to prevent embolic complications. Even manual pulse control might not be sufficient to rule out any distal embolic events creating severe leg ischemia.