Here, we present a protocol for the "isolation zone" technique in the treatment of lumbar disc herniation (LDH) under full-endoscopic spine surgery (FESS), including intervertebral foramen formation, targeted catheterization, nucleus pulposus resection, and annulus fibrosus formation, which together completely block the pain from the nerve conduction pathway.
Lumbar disc herniation (LDH) is a type of serious sinus or sciatic nerve dysfunction caused by nucleus pulposus protrusion and annulus fibrosus tears. Its clinical symptoms often include severe low back pain, limited lumbar movement, sciatic nerve pain in the lower limbs, and even cauda equina syndrome. The common treatment for LDH is a conservative treatment scheme involving medicine, rest, and physical therapy. However, if the conservative treatment scheme is ineffective, a surgical treatment approach is adopted. Traditional open lumbar surgery has some disadvantages, including the potential for severe surgical trauma, severe blood loss during the operation, instability of the lumbar spine, and loss of the lumbar motor unit. Among the minimally invasive surgical schemes, full-endoscopic spine surgery (FESS) is undoubtedly the most appropriate and has the advantages of minimal trauma, high safety, quick postoperative recovery, and the retention of the stable structure and the motor unit of the lumbar spine. However, simultaneously, incomplete removal of the nucleus pulposus and residual nerve dysfunction after surgery can occur. To avoid these shortcomings, we studied a specific spinal endoscopy technique, the “isolation zone” surgical strategy, which can effectively block the pain from the nerve conduction pathway by completely relieving the nerve compression and nerve dysfunction through the orderly treatment of the protruding nucleus pulposus, the fissure of the annulus fibrosus, the sinus nerve, and the surrounding inflammatory soft tissues.
LDH is a common degenerative disease of the spine. LDH is accompanied by multifactorial changes, such as degeneration of the intervertebral disc and the surrounding structures. The interaction between multifactorial degeneration and the nervous system causes pain1. The pain of this disease manifests as low back pain and leg pain, and sometimes LDH can be related to an inability to maintain the same posture or sensory-motor disorder of the lower limbs2. The severe clinical symptoms of LDH bring great pain to the patients and represent a serious medical and social problem3,4. For patients with obvious herniated intervertebral discs or a torn annulus fibrosus, traditional conservative treatments, including drug therapy, physical therapy, and rest, cannot effectively solve their problem5. Lumbar fusion surgery is usually used to treat patients with LDH for whom conservative treatment is ineffective6. However, this surgery has a high economic cost and causes large surgical trauma and destruction of the stable structure of the spine; additionally, the postoperative improvement in low back pain, sensory-motor disturbance of the lower limbs, and lumbar motion function, etc., is sometimes unsatisfactory7. The development of FESS has not only improved the curative effects of lumbar surgery but also reduced the cost and risk of surgery8,9. However, if the nucleus pulposus is not completely removed during endoscopic surgery and the treatment of the pain-inducing factors is not comprehensive, the patient will have low back pain, dysesthesia in the lower extremities, and other adverse reactions after surgery10,11,12,13.
To avoid inadequate removal of the nucleus pulposus during endoscopic surgery and the inadequate relief of postoperative neurological dysfunction, our research team applied a modified spinal endoscopic "isolation zone" technique. The "isolation zone" technology aims to block the pain transmission pathway of the sinus vertebra nerve and sciatic nerve by removing the herniated intervertebral disc, ruptured annulus fibrosus, and hyperplastic inflammatory tissue. In addition, pathogenic inflammatory mediators on the surface of the disc and intraspinal canal are removed13. The "isolation zone" technique can fully decompress the unilateral compressed spinal nerves. This technical strategy is more minimally invasive and effective than traditional surgical methods.
The protocol follows the guidelines of the Ethics Committee of Cangzhou Central Hospital (No.: 20210205). Informed consent was obtained from the patients to include them, and the data were generated as part of this study.
1. Pre-operative preparation
2. Anesthesia and lesion exposure
3. "Isolation zone" technique of spinal endoscopy
4. Intraoperative drug application
5. Post-operative care
FESS with the "isolation zone" strategy was adopted in this study to treat LDH, and this method effectively relieved the patients' low back pain and/or sciatic nerve pain. For all the patients who underwent surgery under local anesthesia, the operation did not have to be interrupted because of unbearable pain. The VAS score, ODI index, and the excellent and good rates of the modified MacNab criteria from the previous study are shown in Table 1.
The MRI re-examination of the lumbar spine after the operation showed that the herniated intervertebral disc disappeared, and the tear of the annulus fibrosus disappeared and healed well, forming an "isolation zone" on the ventral side of the dura mater and nerve root (Figure 2F-I).
Figure 1: Surgical instruments and intraoperative diagrams of the intervertebral foramen plasty. (A) The Tom Shidi locator combined with the guide wire. (B) The bone drill combined with the guide wire. (C) Intraoperative lateral X-ray of the Tom Shidi locator; (D) Intraoperative AP X-ray of the Tom Shidi locator; (E) Intraoperative lateral X-ray of the bone drill. (F) Intraoperative AP X-ray of the bone drill. Please click here to view a larger version of this figure.
Figure 2: Image data of LDH patients before, during, and after the operation. (A,B) The high-intensity zone of the L4/5 segment intervertebral disc annulus fibrosus and the nucleus pulposus protrusion can be seen in the preoperative lumbar MRI. (C,D) The working channel of the spinal endoscopy during the operation. (E) Intraoperative images showing the "isolation area" formed in the nerve root and ventral dura mater after endoscopic decompression. (F,G) At 1 week after the operation, the lumbar MRI was rechecked, and the signal of the fibrillar ring tear disappeared; the range of ventral decompression of the dura mater was sufficient. (H,I) The lumbar MRI was re-examined 10 months after the operation, and the fibrous ring tear disappeared; the surgical scope of the "isolation area" healed well. This figure has been modified with permission from Wang et al.14. Please click here to view a larger version of this figure.
Patients (n = 45) | |
VAS score | |
Pre-operation | 6.95 ± 1.02 |
1 month after operation | 2.64 ± 0.71 |
3 months after operation | 1.80 ± 0.54 |
6 months after operation | 1.42 ± 0.50 |
12 months after operation | 1.27 ± 0.45 |
ODI | |
Pre-operation | 72.84 ± 5.95 |
1 month after operation | 35.1 ± 5.30 |
3 months after operation | 25.22 ± 4.85 |
6 months after operation | 16.78 ± 4.63 |
12 months after operation | 10.91 ± 2.36 |
Treatment effect | |
Excellent | 24 (53.3%) |
Good | 13 (28.9%) |
Fair | 8 (17.8%) |
Table 1: VAS score and ODI index. This table has been modified with permission from Wang et al.14.
LDH is a degenerative disease of the spine that seriously affects daily life and work. The main clinical manifestations are low back pain and sciatic nerve pain. Extreme waist movements, fixed posture, and physical labor can aggravate the symptoms4,15. If conservative treatment cannot alleviate the clinical symptoms, minimally invasive methods are used to treat patients with LDH. Momenzadeh et al. used percutaneous laser disc decompression (PLDD) to treat 30 patients with LDH, and the results showed that the VAS and ODI scores of the patients were decreased after percutaneous laser discectomy16. Zhang et al. treated 307 patients with lumbar disc herniation or lumbar spinal stenosis by endoscopy or microscopy, which effectively relieved acute nerve root symptoms; additionally, there were no differences in the ODI scores and VAS scores at the end of follow-up17. In another study, 24 patients with DLBP were treated with the outside-in technique of percutaneous spinal endoscopy for annulus fibrosus tears18. At the 12 month follow-up, the average VAS score decreased from 6.83 ± 0.87 before the operation to 1.62 ± 0.7718. Therefore, with all these minimally invasive methods, the clinical symptoms are obviously improved. However, most studies focus on minimally invasive surgical tools and surgical approaches, and there are few studies on the specific operation steps and treatment scope19,20.
At present, it is considered that the pathogenesis of LDH mainly involves nucleus pulposus protrusion and an annulus fibrosus tear caused by lumbar degeneration, pain caused by inflammatory factors and produced by pain receptors of the sinus nerve when it is tightly covered by the intervertebral disc, and radiation pain of the lower limbs caused by sciatic nerve compression and ischemia edema21. In particular, under the action of oppressive stimulation of inflammatory mediators in the herniated nucleus pulposus, hyperplastic inflammatory nerve endings can appear at the rupture of the annulus fibrosus and in the nucleus pulposus, thus inducing low back pain22. The herniated disc squeezes the ligaments in the spinal canal, nerve root, and dura mater, which causes continuous stimulation of the inflammatory mediators in the annulus fibrosus tear and, thus, synergistic neurological dysfunction. The continuous stimulation of inflammatory mediators leads to the formation of a pannus and new nociceptive nerve fibers near the annulus fibrosus and, gradually, chronic and scattered inflammatory lesions, which aggravate the pain stimulation23. If the herniated nucleus pulposus, annulus fibrosus, and surrounding nonbacterial inflammatory tissues are not thoroughly removed during endoscopic surgery, there will often be postoperative residual low back pain or sciatic nerve stimulation of the lower limbs.
Compared with traditional endoscopic discectomy, the "isolation zone" technique for the treatment of lumbar disc herniation has more complicated endoscopic operation requirements and requires more surgical details. The key points of the "isolation zone" surgical strategy are the accurate location and safe anatomical access. The range of endoscopic exploration and operation needs to reach the posterior inferior edge of the upper vertebral body at the proximal end, the posterior superior edge of the lower vertebral body at the distal end, and the longitudinal fibers of the posterior longitudinal ligament inward. The protruding nucleus pulposus must be removed as completely as possible, the hyperplastic inflammatory tissue in the spinal canal must be removed, the intervertebral disc that is protruding and compressing the spinal nerve must be removed, the sinus plexus must be blocked with radio frequency, the torn part of the annulus fibrosus should be removed, shrunk, and denervated, the periphery of the posterior longitudinal ligament should be denervated, and an "isolation zone" should be formed around the nerve root and dura mater to block the conduction of inflammatory factors and pain by the nerve fibers.
In this study, the isolation zone technology of FESS used has the following advantages in treating LDH. 1) The application of selective nerve block through the intervertebral foramen before the endoscopic surgery allows the surgeon to accurately find the involved segment of the LDH, especially for patients with complicated symptoms and unclear involved segments, and selective nerve block can avoid disc injury and false positives caused by the injection of contrast agent into the disc. 2) The FESS isolation zone technique has little influence on the stable structure of the lumbar spine and allows the motor unit of the spine to be retained. It is obviously superior to traditional fusion surgery in preventing the postoperative degeneration of adjacent segments. 3) Under local anesthesia, patients can correctly report on the neurological status of the lower limbs during the operation. The incidence of nerve injury is low, patients can exercise soon after the operation, and lumbar function can recover quickly after surgery. 4) The isolation belt technology can be used to comprehensively treat all the pathogenic factors of LDH, with few residual symptoms after surgery and satisfactory treatment effects.
The "isolation zone" technique of the FESS has several limitations. As the range of treatment under endoscopy is large, there are certain requirements for the accuracy of the placement of the endoscope working channel. In addition, this technique requires the identification and thorough cleaning of various pathogenic factors in the involved segment of the lumbar disc herniation. This technique also requires sufficient intervertebral foramen formation because it is sometimes necessary to constantly move the direction of the endoscope to achieve sufficient surgical vision. If the ventral facet of the facet joint is not sufficiently removed or the intervertebral foraminoplasty is not sufficient, the scope of the endoscope treatment will often be limited, so there are certain requirements for the operator's endoscopic operation level. If the operator wants to fully understand and master the "isolation zone" technique, the learning curve is steep.
The FESS "isolation zone" technique is a very significant technique in the treatment of LDH. Due to its comprehensive treatment strategy and effective blocking pain from the nerve conduction pathway, this technique can also play an important role in the treatment of lumbar spinal stenosis, lumbar spondylolisthesis, and discogenic low back pain in the future.
The authors have nothing to disclose.
None.
18 G puncture needle | tong lu | KB401.061 | |
3.7 mm spinal endoscope | joimax | FS6342181C | |
4-0 nonabsorbent surgical suture | Johnson & Johnson | WB761 | |
7.5 mm working channel | maxmore | 1001-ES04 | |
Bone drill | maxmore | 1001-BD(001-005) | 4 mm, 5 mm, 6 mm, 7 mm, 8 mm diameter |
C-arm X-ray machine | GE | OEC one | |
Catheters | maxmore | 1001-DC 001 | |
Expansion guide rod | maxmore | 1001-DC 002 | |
Flexible bipolar radiofrequency | tian song | G8002.2 | |
Guide wire | maxmore | 1001-GW 003 | 1mm diameter |
Nucleus pulposus forceps | maxmore | 1001-EF 001 003 | 0°and 15° |
Tom Shidi locator | maxmore | 1001-TS 001 |