Minimally invasive endoscope-assisted foraminotomy of the lumbosacral neuroforamen in dogs: Establishment of surgical technique and ex vivo evaluation.
Bekiaridis D1, Pozzi A*1, Steffen F2, Guevar J3, Smolders LA*1
1Clinic for Small Animal Surgery, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland, 2Clinic for Small Animal Neurology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland, 3Clinic for Small Animal Neurology, Vetsuisse-Faculty, University of Bern, Bern, Switzerland.
Objectives:
Dorsal foraminotomy (DF) is an established surgical technique for treating lumbosacral foraminal stenosis in dogs. To improve visualization and safety, we aimed to 1) establish a surgical technique for minimally invasive endoscope-assisted foraminotomy (MIEF) of L7-S1 and 2) to compare visualization, safety and efficacy between MIEF and conventional DF.
Methods:
A surgical technique using a 3.0mm arthroscope (MIEF-A) or a 1.9mm Nanoscope (MIEF-N) was developed in 6 cadaveric spines. Subsequently, bilateral foraminotomy of L7-S1 was performed in 12 spinal specimens (24 neuroforamina), treated by 1) DF, 2) MIEF-A or 3) MIEF-N (n=8/group). Visualization and iatrogenic nerve root damage were qualitatively assessed intra- and post-operatively. Volumetric enlargement of the lumbosacral neuroforamen was calculated using computed tomography and statistically compared between groups using paired T-tests.
Results:
A surgical procedure for MIEF was successfully established. MIEF-A and -N provided good and direct visualization of the L7 nerve root in 100.0% and 57.0% of the cases, respectively, whereas DF only provided moderate (75.0%) or poor (25.0%) visualization, necessitating the use of a nerve hook. Iatrogenic nerve root damage was observed in none of the MIEF-A cases, while for MIEF-N and DF iatrogenic damage was found in 12.5% of the cases. DF and MIEF resulted in a significant enlargement of the neuroforamen (mean±SD: +58.4±33.7%, P<0.01). However, MIEF-A resulted in a significantly higher enlargement compared to DF (+76.8±33.4% and +46.4±23.8%, respectively, P= 0.03).
Conclusions:
MIEF-A provides superior visualization, safety and efficacy compared to DF. We propose MIEF-A as a novel surgical technique for treating dogs with lumbosacral foraminal stenosis.