In the past 10 years, the number of lumbar dynamic surgery has increased significantly. Dynamic stabilization without fusion can be advocated to many advantages, with less trauma, short operation time and less bleeding. Considering the year of our case, more and more operations are performed in elderly patients and patients with various diseases, both of which are associated with a higher incidence of complications. In addition, the incidence of complications was positively correlated with the increase of device complexity. In recent years, the number of patients who need to revision surgery is close to 10%. This challenge is exacerbated by the significant increase in the number of complex lumbar dynamic surgery in the elderly(3, 4).
The most effective treatment of patients with low back and leg pain after lumbar dynamic surgery depends on the accurate diagnosis of anatomical and physiological changes. The most common diagnosis is foraminal stenosis, discogenic pain, or recurrent disc herniation. Hypertrophy of the superior articular process of the lower vertebral body leads to compression of the nerve root at the outlet of the lateral foramen, which is a consensus on the causes of nerve root symptoms, especially for patients who have failed previous lumbar dynamic surgery (5). These lesions have characteristic physical manifestations and imaging studies, which can distinguish them from other etiologies of radiculopathy. We propose a lesion-specific, facet-sparing surgical technique (6).
After the first recognition of spinal canal stenosis in 1802, the understanding of spinal canal stenosis gradually formed in the next 150 years. In traditional surgery, lateral canal stenosis is most often missed or undertreated. The structure of the nerve root canal is semi tubular, and the nerve root goes from the sheath to the intervertebral foramen. The proximal part of the nerve root canal, also known as the intervertebral or subarticular part, is limited by the superior articular process and facets on the posterolateral side and by the intervertebral disc on the anterolateral side. The distal end of the nerve root canal is equivalent to the lateral recess, that is, the lateral angle of the pedicle level intervertebral foramen. The inlet and outlet of intervertebral foramen are located at the lateral and medial edges of pedicle. Hypertrophy of the inferior articular process may only lead to stenosis of the central part of the spinal canal. The superior articular process leads to the deformity of the medial, subarticular and lateral parts of the nerve root canal. According to our experience of percutaneous endoscopy through intervertebral foramen, in many cases of failed lumbar dynamic surgery, the lateral recess often leads to residual unrecognized stenosis. Hypertrophy of ligaments or bone in the superior articular process leads to intervertebral foramen stenosis, and any degree or additional disc herniation in the protruding area, including the inflatable ring, can also affect the nerves in the sheath capsule and intervertebral foramen (7–9)
Endoscopic foraminoplasty was performed to either decompress the bony foramen for foraminal stenosis, or to be convenient for endoscopic visual verification of the decompressed exiting and traversing nerve in residual/recurrent patients with continued leg and/ or back pain after lumbar spinal dynamic surgery. The annulus is often inflated and expands with the unloading and loading of spinal segments, resulting in the compression of intervertebral foramen. No foramen nerve from the existing nerve branches was found to come from the dorsal branch. They have a diameter of 1–2 mm, no pain in palpation, and will not cause postoperative sensory disturbance during transection. The nerve walks below the superior articular process along the ligamentum of the intervertebral foramen, which can reduce axial back pain during ablation. However, resection of larger nerves in the foramen may lead to postoperative sensory impairment. At present, we cannot confirm the cause of color vision after operation, because color vision may occur even if the nerve is not affected. We tell the patient that this is a risk that cannot be eliminated. Fortunately, this is usually temporary and can be alleviated by postoperative transforaminal and sympathetic block. The axilla, accessed through foraminoplasty, is the location that is often under appreciated as a area for pathological anatomy causing FBSS. The pathological anatomy is considered as foraminal osteophytosis, foraminal stenosis, compressive foraminal fibrosis, or recurrent or residual patients presenting with back and leg pain.The axilla includes hidden pathoanatomy, such as intervertebral foramen herniation and synovial cyst. The dorsal branch can easily be mistaken for pathological anatomy. In a parallel study of dorsal rhizotomy for axial back pain, it was determined that facet pain was also relieved by dorsal endoscopic (visual) rhizotomy rather than fusion (10–12).