Comparison of the clinical efficacy and safety of two spinal endoscopic techniques for the treatment of ossification of the ligamentum flavum in the thoracic spine

Abstract

Purpose: The purpose of this study was to compare the clinical efficacy and safety of the percutaneous endoscopic (PE) technique and the unilateral biportal endoscopic (UBE) technique for the treatment of thoracic ossification of the ligamentum flavum (T-OLF).

Methods: This study retrospectively analyzed T-OLF patients who received endoscopic surgical treatment from January 1, 2020, to December 31, 2022. Patients were divided into a PE group and a UBE group according to the surgical method. The basic information of the patients was recorded. Preoperative and postoperative neurological status was evaluated using the mJOA score, American Spinal Injury Association (ASIA) sense score (ASS), and ASIA motor score of the lower extremities (AMS). The mJOA recovery rate (RR) was also calculated. T-OLF can be diagnosed on the basis of sagittal Magnetic Resonance Imaging (MRI) and axial Computed Tomography (CT).

Results: A total of 64 patients were followed for an average of 12-24 months. 33 patients underwent UBE surgery, and 31 patients underwent PE surgery. There was no significant difference in baseline characteristics between the two groups (p > 0.05). Neurological function was significantly improved in both groups after surgery. Compared with the PE group, the UBE group experienced better postoperative clinical efficacy, and the difference was statistically significant (p < 0.05). Postoperative CT and MRI revealed that the degree of spinal cord compression in patients in the UBE and PE groups was relieved. 4 patients in the PE group and 1 patient in the UBE group had dural sac tears. 3 patients with upper thoracic vertebrae in the PE group exhibited transient neurological deficits. These complications did not cause serious consequences.

Conclusion: For patients with T-OLF, both UBE and PE can effectively alleviate nerve compression and relieve symptoms. UBE uses two channels for observation and operation, leading to more effective and safer clinical outcomes.

Keywords: clinical efficacy; minimally invasive spine surgery; percutaneous endoscopic; thoracic ossification of the ligamentum flavum; unilateral biportal endoscopic.

Figure 1

(a) Lineation-on-body; (b) Cannulas converging on the surface of the lamina; (c) The lamina at the head; (d) The lamina at the end; (e) The thinned ossified ligamentum flavum; (f) Use a nerve hook to separate the deep surface of the ossified ligamentum flavum; (g) Remove the ossified ligamentum flavum with a Kerrison rongeur; (h) Complete decompression of the spinal cord.

Figure 2

(a,b) Preoperative MRI shows ossification of the thoracic ligamentum flavum (Round); (c,d) Preoperative CT shows severe ossification of the thoracic ligamentum flavum (Fused); (e,f) Postoperative CT shows that the ossification has been removed and spinal cord decompression has been successful, and a small amount of cerebrospinal fluid leaked out; (g,h) Postoperative CT and 3D reconstruction show that the spinal canal has been opened and the ossification has been removed.

Figure 3

(a,b) Preoperative MRI shows ossification of the thoracic ligamentum flavum (Beak); (c,d) Preoperative CT shows ossification of the thoracic ligamentum flavum (Enlarged); (e,f) Postoperative CT shows that the ossification has been removed and spinal cord decompression has been successful; (g,h) Postoperative CT and 3D reconstruction show that the spinal canal has been opened and the ossification has been removed.