BACKGROUND In posterolateral percutaneous transforaminal endoscopic lumbar surgery, foraminoplasty is currently performed by resecting part of the superior articular process together with surrounding soft tissues. This procedure remains technically demanding. An ideal foraminoplasty technique should be safe, easy, efficient, and controllable and should minimize X-ray exposure. OBJECTIVE To introduce a novel foraminoplasty technique that is designed in an attempt to obtain the ideal state. METHODS The technique is introduced step by step by case illustration. Briefly, the technique is based on the addition of a novel instrument, named a “Foraminoplasty Working Tube,” to the commercialized spinal endoscope system. Through the foraminoplasty working tube, the foraminoplasty procedure can be performed under either reduced X-ray guidance or direct endoscopic view. RESULTS The technique allows the surgeon to perform an accurate resection of the superior articular process by easily adjusting the foraminoplasty working tube to the target area. To a great extent, the volume of the bone resected is predictable and controllable and just meets the demands of the operation without excessive resection of the superior articular process. CONCLUSION The present technique would potentially be a safer, easier, and more efficient foraminoplasty technique.

Background Percutaneous transforaminal endoscopic surgery has been used as a surgical measure for lumbar lateral recess stenosis. However, the necessary decompressive range has never been clearly documented in detail. Here, we discuss the effectiveness of a percutaneous transforaminal endoscopic procedure with clearly defined decompressive range. Material/Methods The relevant data were retrospectively collected from a series of degenerative lateral recess stenosis patients who acquired a prospectively designed percutaneous transforaminal endoscopic procedure in our department. The decompressive procedure mainly included undercutting of superior articular process and intervertebral disk annuloplasty. Leg pain and back pain was evaluated using visual analogue scale (VAS). The functional status was assessed using Oswestry disability index (ODI). The clinical results were also evaluated using MacNab criteria. Results From May 2014 to October 2018, a total of 33 patients who met our inclusion criteria were included for analysis. There were no perioperative complications. Leg pain VAS decreased from preoperative score of 6.18±2.38 to final follow-up score of 0.45±1.00 ( P <0.01). Back pain VAS decreased from preoperative score of 1.88±2.19 to final follow-up score of 0.64±1.02 ( P <0.01). ODI (%) decreased from preoperative score of 47.86±18.15 to final follow-up score of 6.29±6.75 ( P <0.01). At the final follow-up, the results of MacNab criteria were excellent in 18 cases (54.55%), good in 14 cases (42.42%), fair in 1 case (3.03%) and poor in 0 cases. None of the patients complained of recurrence of the symptoms during follow-up. Conclusions Undercutting of “superior articular process neck” plus intervertebral disk annuloplasty is sufficient for lumbar lateral recess decompression in a transforaminal approach.