AbstractTransforaminal endoscopic lumbar discectomy (TELD) is effective and feasible for recurrent disc herniation, and can reduce surgery-related complications and the operation time. After lumbar discectomy, the disc height significantly decreases, and disc degeneration and facet arthropathy might progress. These changes can make it difficult to achieve transforaminal endoscopic access to the epidural space, increasing the likelihood of exiting nerve injury. Endoscopic foraminoplasty facilitates the engagement of the working cannula via the intervertebral foramen, allowing cannula access near the herniated disc for the successful performance of TELD. We present a successful case of TELD using bone drill-assisted foraminoplasty for recurrent disc herniation to demonstrate this technique. This foraminoplasty technique is relatively safe and time-efficient, significantly aiding the TELD procedure.
WRITTEN TRANSCRIPT0:00 TitleWe will discuss our experience with transforaminal endoscopic lumbar discectomy (TELD) using bone drill-assisted foraminoplasty in recurrent disc herniation.
0:20 Recurrent disc herniationRecurrent disc herniation presents a significant challenge, but TELD is both effective and feasible, reducing surgery-related complications and operative time. After discectomy, issues such as disc height reduction, facet arthropathy, and foraminal narrowing can make endoscopic access difficult and increase the risk of exiting nerve injury.
0:42 Endoscopic foraminoplastyForaminoplasty is a technique to widen the foramen, allowing better access to the cannula near the herniated disc and removing the superior articular process (SAP). Endoscopic foraminoplasty was first introduced by Knight et al. [1] in 2001 using a Holmium:YAG side-firing laser undercutting of facet joint, discectomy, mobilization of exiting and traversing nerve roots, and ablation of osteophytes.
1:13 Summary of literatureHere's a summary of key studies on foraminoplasty:
In foraminal stenosis, Knight et al. [1] reported a 73% success rate using a laser, with a 5% revision rate. Ahn et al. [2] achieved an 82% success rate using endoscopic drill, laser, and micropunch, with a 3% revision rate. In disc herniation, Schubert and Hoogland [3] reported a 95% success rate using a reamer, with a 3.6% revision rate. Choi and Park [4] also reported high success rates using endoscopic drills and reamers, with low revision rates.
1:52 Target of ForaminoplastyThe targets of foraminoplasty vary depending on the type of disc herniation [5]. L5–S1 disc herniation involves the cranial tip of SAP. Central disc herniation and recurrent disc herniation involve the mid-part of SAP. Down-migrated disc herniation involves the base of SAP and partial upper pedicle.
2:13 IndicationEndoscopic lumbar foraminoplasty is indicated for: high-grade down migration, downward sequestration, decreased disc height, recurrent disc herniation, central disc herniation with a wide lamina angle, L5-S1 disc herniation with a high iliac crest [6]. For these conditions, foraminoplasty may be required to facilitate TELD.
2:38 EquipmentWe use the transforaminal system for these procedures. The bone drill is an essential tool in our foraminoplasty procedures. Patients are positioned prone and the procedure is performed under local anesthesia.
2:51 Case 1 PresentationCase 1 involves a 79-year-old male with right leg radiating pain and a history of microscopic discectomy at L4–5 6 months ago. Physical examinations reveal right great-toe dorsiflexion weakness. Preoperative magnetic resonance imaging (MRI) showed downward migrated disc herniation with previous laminectomy. X-ray showed foraminal stenosis.
3:15 Surgical Procedure - ForaminoplastyForaminoplasty was performed using a bone drill. First, perform a discography. Then, place the needle in the craniocaudal direction at the base part of the SAP. Insert the smallest bone drill and ream the area. Gradually increase the diameter of the drill for reaming. After removing the final bone drill, insert the working cannula.
3:40 Surgical Procedure - DiscectomyWhen the endoscope is inserted, the right side will be cranial, the left side will be caudal, the lower part will be the disc space, and the upper part will be the epidural space. The ruptured disc fragment will be immediately visible, and the disc fragment is removed.
Once several pieces of the disc are removed, the nerve root and dural sac will be visible, and pulsation will be noticeable. This indicates that sufficient decompression has been achieved.
4:25 Postoperative CoursePostoperative MRI shows successful decompression with no complications. Yellow arrows indicate foraminoplasty sites.
4:33 Case 2 PresentationCase 2 involves a 69-year-old female with left leg radiating pain and a history of microscopic discectomy at L4–5 twelve years ago. Physical examinations reveal left great-toe dorsiflexion weakness and decrease of sensory as L5 dermatome. Preoperative MRI showed tiny recurrent disc herniation compressing L5 nerve root.
5:00 Surgical Procedure - ForaminoplastyFirst, perform a discography. Then, place the needle in the craniocaudal direction at the base part of SAP. Insert the smallest bone drill and ream the area. Gradually increase the diameter of the drill for reaming. After removing the final bone drill, insert the working cannula.
5:21 Surgical Procedure - DiscectomyIn the endoscope view, the left side is cranial, the right side is caudal, the lower part is the disc space, and the upper part is the epidural space. Remove the ruptured disc fragments from the disc space and feel the pulsation in the epidural space. Use a probe to confirm decompression around the nerve root.
6:06 Surgical PhotoThe photo shows multiple disc fragments. Blood-tinged disc means ruptured disc fragment.
6:12 Postoperative CoursePostoperative MRI shows successful decompression with no complications. Both patients had no intraoperative complications and were discharged on postoperative day 1 with immediate pain relief. Incisions were closed with glue.
6:27 Surgical TipsSome surgical tips include – a more caudal approach along the superior border of the inferior pedicle may be safer. Serial dilation and sequential reaming can reduce injury to the exiting nerve root [7]. Avoid reaming with too steep an angle to prevent violation of the disc space. The bone drill should not go beyond the medial pedicular line.
NOTESConflict of Interest KCC, a member of the Editorial Board of Journal of Minimally Invasive Spine Surgery & Technique, is the corresponding author of this article. However, he played no role whatsoever in the editorial evaluation of this article or the decision to publish it. Author has no conflict of interest to declare. REFERENCES1. Knight MT, Vajda A, Jakab GV, Awan S. Endoscopic laser foraminoplasty on the lumbar spine--early experience. Minim Invasive Neurosurg 1998;41:5–9.
2. Ahn Y, Oh HK, Kim H, Lee SH, Lee HN. Percutaneous endoscopic lumbar foraminotomy: an advanced surgical technique and clinical outcomes. Neurosurgery 2014;75:124–33.
3. Schubert M, Hoogland T. Endoscopic transforaminal nucleotomy with foraminoplasty for lumbar disk herniation. Oper Orthop Traumatol 2005;17:641–61.
4. Choi KC, Park CK. Percutaneous endoscopic lumbar discectomy for L5-S1 disc herniation: consideration of the relation between the iliac crest and L5-S1 disc. Pain Physician 2016;19:E301–8.
5. Choi KC, Shim HK, Park CJ, Lee DC, Park CK. Usefulness of Percutaneous Endoscopic Lumbar Foraminoplasty for Lumbar Disc Herniation. World Neurosurg 2017;106:484–92.
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