Is there an association between digital oximetry desaturation and changes in somatosensory-evoked potentials during anterior lumbar interbody fusion?

BACKGROUND

Anterior lumbar interbody fusion (ALIF) is widely employed in the treatment of degenerative lumbar disorders. However, ALIF may require manipulation or retraction of major vascular structures, thereby increasing the risk of transient ischemia. Intraoperative neurophysiological monitoring with somatosensory-evoked potentials (SSEPs), combined with digital oximetry (DO), may more effectively detect the onset of lower-extremity hypoperfusion or major vascular compromise during ALIF.

METHODS

Thirty consecutive patients underwent ALIF for lumbar spondylodiscoarthropathy. Intraoperative SSEP recording and digital pulse oximetry were performed; episodes of desaturation (SpO2 < 90%) and SSEP changes (amplitude reduction or latency increase) were documented. Associations between desaturation and SSEP alterations were analyzed using Fisher's exact test.

RESULTS

Peripheral desaturation and SSEP alteration each occurred in one patient (3.3%), with no significant association (P > 0.999). No vascular injuries were identified. Postoperatively, all patients experienced significant lumbar pain relief (median verbal numerical scale reduction from 8 to 2; P < 0.001), with sensory improvement in 69% and motor recovery in one of two cases with paresis.

CONCLUSION

A causal link between DO desaturation and SSEP changes during ALIF appears unusual. Nevertheless, concurrent monitoring enhances intraoperative safety and is advisable in procedures involving vascular manipulation. The results support the safety and clinical efficacy of the anterior approach when performed by experienced teams in selected patients.