LDH is a common and frequently occurring disease in spinal surgery. The main manifestations are back and leg pain, weakness of movement, decreased reflex function, and sensory disorders. [17] Most patients improve significantly within 3–6 months of symptom onset with conservative treatment. For patients with progressive neurological deficits caused by severe nerve root compression or patients with intractable symptoms, surgical relief of compression is the most effective way to relieve symptoms. [18] FD is representative of open surgery. It is an interlaminar approach that can thoroughly remove hyperplastic bone, hyperplastic ligaments, and herniated intervertebral discs under direct vision to perform complete decompression of nerve roots and spinal canals and is considered the gold standard for the treatment of lumbar disc herniation. [19] However, due to the extensive range of paravertebral tissue dissection, the muscle loses distal innervation, which may cause intractable back pain after surgery. At the same time, the weakening of the muscle strength of the lumbar back may lead to the occurrence of lumbar instability. [20, 21] To further improve the clinical effect of surgery, spine surgery has entered the era of minimally invasive surgery under the continuous research of spine surgeons.
Studies have shown that UBE is similar to FD in lower limb pain control, dysfunction, and patient satisfaction, but it has the advantages of less blood loss, shorter hospital stay, and less postoperative back pain. [22] PAO et al.[23] applied UBE technology to lumbar spinal stenosis, and postoperative MRI examination showed that the dural sac area increased from 71.4 ± 36.5 mm2 to 177.3 ± 59.2 mm2. Postoperative CT examination of the lumbar spine showed that the retention rate of facet joints was 84.2% on the approach side and 92.9% on the contralateral side. The spine is more stable. Zenya Ito et al.[24] compared the clinical effect of microendoscopic laminectomy (MEL) with that of unilateral biportal endoscopic laminectomy (UBEL) for single-level lumbar spinal stenosis. Postoperative CT results showed that the MEL and UBEL areas of bone resection were 1.5 cm2 and 1.0 cm2, respectively. The retention rate of the ipsilateral facet joint was 78% in the MEL group and 86% in the UBEL group; the retention rate of the contralateral facet joint was 85% in the MEL group and 94% in the UBEL group; and the retention rate of the UBEL operative joint was higher, which was conducive to postoperative rehabilitation.
This study included 50 patients with LDH who underwent nerve root decompression, which significantly improved postoperative symptoms. The study confirmed the feasibility of UBE and FD as surgical methods for treating LDH. The UBE group had significantly shorter incision lengths and postoperative hospital stays than the FD group. UBE is performed using two small incisions in the back of the spine, which helps to protect the paravertebral muscles. This allows patients to engage in early activities and functional exercises to ensure a smoother postoperative rehabilitation process. On the other hand, FD requires a larger range of muscles in the back, resulting in a more extended bedtime postoperatively. This is one of the reasons why the hospital stay for the FD group was more extended than that of the UBE group. The UBE group had a longer operation time than the FD group. This is because UBE uses an entire endoscope, which requires more advanced surgical skills and has a longer learning curve. [25, 26] As a new technology, it is necessary to continually review the technical summary, become familiar with instrument use, optimize surgical steps, and reduce operation time while ensuring safety.
Both UBE and FD effectively improve leg symptoms, mainly due to thorough nerve root decompression. In terms of improving lumbar pain and dysfunction, UBE was found to be superior to FD. This could be attributed to the fact that UBE caused less injury to the paravertebral muscle nerve. Additionally, the retention rate of the upper lamina and facet joint was better in the UBE group than in the FD group. Using an enlarged endoscope during the UBE operation helped preserve bone tissue to a great extent. The facet joint is crucial in maintaining spinal stability, and FD is performed under direct vision. It requires a significant amount of bite on the upper and lower lamina and facet joints of the duty space to ensure complete exposure of the ligament flavum and nerve roots. [27, 28] UBE is performed using an endoscope, providing a clear vision field. This enables the preservation of facet joints and lamina to a maximum extent, leading to a more precise removal of diseased tissue.
Additionally, it contributes to ensuring postoperative spinal stability to some extent. No significant spinal instability was observed in either the UBE or FD groups during the 1-year follow-up period. The intervertebral space height change was significantly greater in the UBE group than in the FD group. This difference can be attributed to the precise removal of the nucleus pulposus during the operation in the UBE group. In contrast, the FD group had to use forceps to remove a specific amount of annulus fibrosus to obliterate the nucleus pulposus. This procedure resulted in a better change in the intervertebral space height in UBE compared to FD. UBE has demonstrated effectiveness in safeguarding bone structure and soft tissue, and it can also contribute to the preservation of vertebral space height to a certain extent.
Our hospital carried out UBE earlier in the province. Currently, we have successfully performed over 200 surgical cases, accumulating valuable surgical experience. Based on our observations, we have identified several essential considerations: ① The introduction of independent working channels and endoscopic channels has eliminated the limitations of previous single-channel endoscopic operations. This advancement allows surgeons to perform flexible operations with a clear field of vision. ② Using water as a medium in UBE operations has shown promising results in reducing blood loss. Additionally, continuous saline irrigation has been found to lower the infection rate. ③ During the surgery, it is crucial to maintain the systolic blood pressure below 105 mmHg. This precautionary measure prevents excessive bleeding that could obstruct the visual field and increase the risk of dural injury. ④ To avoid increased cerebrospinal fluid pressure caused by high water pressure, a saline lavage solution of 3000 ml was used. The suspension height was 50–60 cm above the operating table. ⑤ Intraoperative anaesthesia coordination plays a critical role in the success of UBE procedures. Shallow anaesthesia or inadequate muscle relaxation may result in intravertebral bleeding. ⑥ It is essential to maintain unobstructed water flow during the operation. Creating a good channel and utilizing half cannula assistance can promote unobstructed water flow. ⑦ Intraoperative fluoroscopic positioning can help clarify the responsibility gap and prevent surgical errors. Additionally, for cases of severe hyperplasia and degeneration, endoscopic fluoroscopic positioning can clarify the anatomical structure under the endoscope. ⑧ Hemostatic technology is a crucial aspect of UBE surgery. Prior to decompressing the yellow ligament, a double maximum power radiofrequency plasma surgical electrode can be used for electrocoagulation and hemostasis. After decompressing the yellow ligament, nerve tissue becomes exposed, requiring a low-power radiofrequency surgical electrode for electrocoagulation and hemostasis. ⑨ It is vital to protect the facet joints during intraoperative decompression. Inadequate decompression may result from removing too few facet joints, while removing too many can harm the spine's stability. It is recommended to excise within the inner edge of the pedicle.
This study has certain limitations that should be acknowledged. First, the sample size used in the study is small, which may lead to biased statistical results. Additionally, the short follow-up time only permits an examination of the short-term clinical impact of the operation. To mitigate statistical bias, future research should focus on expanding the sample size, conducting multicenter prospective randomized controlled studies, and extending the duration of the follow-up period.