Patient selection protocols for endoscopic transforaminal, interlaminar, and translaminar decompression of lumbar spinal stenosis

Álvaro Dowling, Kai-Uwe Lewandrowski, Fabio Henrique Pinto da Silva, Jaime Andrés Araneda Parra, Daniela Molero Portillo, Yohanna Carolina Pineda Giménez


Background: The indications of different endoscopic and endoscopically assisted translaminar approaches for lumbar spinal stenosis are not well-defined, and validated protocols for the use of the transforaminal over the interlaminar approach are lacking.
Methods: We performed a retrospective study employing an image-based patient stratification protocol of stenosis location (type I—central canal, type II—lateral recess, type III—foraminal, type IV—extraforaminal) and clinical outcomes on 249 patients consisting of 137 (55%) men and 112 (45%) women with an average age of 56.03±16.8 years who underwent endoscopic surgery for symptomatic spinal stenosis from January 2013 to February 2019. The average follow-up of 38.27±27.9 months. The primary clinical outcome measures were the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and modified Macnab criteria.
Results: The frequency of stenosis configuration in decreasing order was as follows: type I—121/249; 48.6%, type III—104/249; 41.8%, type II—15/249; 6%, and type IV—9/249; 3.6%. The transforaminal approach (137/249; 55.0%) was used in most type II to IV lesions followed by the interlaminar approach (78/249; 31.3%), and the full endoscopic approach (12/249; 4.8%), and the endoscopically assisted translaminar approach (8/249; 3.2%) which was exclusively used for type I lesions. Macnab outcomes analysis showed Excellent in 47 patients (18.9%), Good in 178 (71.5%), Fair in 18 (7.2%) and Poor in 6 (2.4%), respectively. Paired two-tailed t-test showed statistically significant VAS (5.46±2.1; P<0.0001) and ODI (37.1±16.9; P<0.0001) reductions as a result of the endoscopic decompression surgery. Cross-tabulation of the Macnab outcomes versus the endoscopic approach and surgical technique confirmed beneficial association of the approach selection with Excellent (P=0.001) and Good (P<0.0001) outcomes with statistically significance.
Conclusions: This study suggests that in the hands of skilled endoscopic spines surgeon use of an image-based stenosis location protocol may contribute to obtaining Excellent and Good clinical outcomes in a high percentage (93%) of patients suffering from lumbar stenosis related radiculopathy. Additional comparative studies should examine the prognostic value of choosing the endoscopic approach on the basis of the proposed four-type stenosis protocol by correlating its impact on outcomes with preoperative diagnostic injections and intraoperative direct visualization of symptomatic pain generators under local anesthesia and sedation.