Biportal endoscopic foraminotomy of the L7-S1 neuroforamen in dogs: Description of surgical technique and ex vivo comparison with conventional open dorsolateral foraminotomy.

Objective (1) To establish a surgical technique for minimally invasive biportal endoscopic foraminotomy (BEF) of L7-S1 in dogs using arthroscopic equipment. (2) To compare BEF and dorsolateral foraminotomy (DF) and (3) to provide clinical results of the first client-owned dog treated by way of BEF.Study Design Ex vivo cadaveric study, case report.Sample Population A total of 18 cadaveric lumbosacral spinal specimens (L3-S3). A 4-year-old mixed breed dog with lumbosacral foraminal stenosis.Methods A surgical technique using a 3.0 mm 30° arthroscope (BEF-A) or a 1.9 mm 0° needle arthroscope (BEF-N) was developed in six cadaveric spines. Bilateral L7-S1 foraminotomy was performed in 12 spinal specimens (24 neuroforamina) by (1) DF, (2) BEF-A or (3) BEF-N (n = 8/group). Visualization, iatrogenic nerve root damage, and foraminal enlargement were compared between the three procedures.Results BEF-A provided superior visualization compared to DF and BEF-N (p < .05). Iatrogenic nerve root damage was not observed in any of the procedures. All procedures resulted in significant enlargement of the neuroforamen (58 ± 33%, p < .01). BEF-A (81.3 ± 30.0%) resulted in significantly more enlargement compared to DF (59.7 ± 33.7%, p = .03) and BEF-N (51.1 ± 38.8%, p = .04). BEF-A was successfully used to treat a client-owned dog with L7-S1 foraminal stenosis.Conclusion BEF-A provided superior visualization and efficacy compared to DF.Clinical Significance BEF-A is a safe and effective surgical technique for treating dogs with L7-S1 foraminal stenosis. The technique should be evaluated in larger clinical studies.