Application of RhBMP-2 in Percutaneous Endoscopic Posterior Lumbar Interbody Fusion

Abstract

Background

To investigate the application of recombinant human bone morphogenetic protein-2 (RhBMP-2) in Percutaneous Endoscopic Posterior Lumbar Interbody Fusion (PE-PLIF).

Materials and methods

The study randomly included 102 patients with lumbar spondylosis who underwent PE-PLIF at our hospital from April 2020 to August 2022. Following the random number table method, these subjects were graded as a study group of 51 cases and a control group of 51 cases. Posterior pedicle screw fixation treatment with RhBMP-2 or autologous bone was given respectively. The surgical status and perioperative complications, as well as lumbar spine function before surgery and at 1 and 12 months after surgery [Prolo score and Japanese Orthopaedic Association (JOA) score] of patients in the two groups were observed, and the postoperative fusion rate and cage displacement rate at 1 and 12 months after surgery were compared between the two groups. The degree of vertebral body slippage, intervertebral space height, and changes in quality of life were compared between the two groups before and 12 months after surgery.

Results

There was no significant difference in hospital stay, surgical time, bleeding volume, and incidence of complications between the two groups (P > 0.05)0.12 months post-operation, the Prolo and JOA scores of both groups largely increased, which were significantly higher in the RhBMP-2 group than the control (P < 0.05). 12 months post-operation, the fusion rate in the RhBMP-2 group was 86.27%, which was significantly higher than that of 54.90% in the control group (P < 0.05). 12 months post-operation, the Cage displacement rate in the RhBMP-2 group was 5.88%, which was lower than that of 21.57% in the control group (P < 0.05). 12 months post-operation, the height of the intervertebral space in both groups largely increased, which was significantly higher in the RhBMP-2 group than in the control (P < 0.05). The degree of vertebral body slippage was significantly reduced in both groups, and the RhBMP-2 group was significantly lower than the control (P < 0.05). The cognitive function, social function, physiological function, and mental health were evidently improved in both groups 12 months post-operation and were significantly higher in the RhBMP-2 group than in the control (P < 0.05).

Conclusion

RhBMP-2 material in PE-PLIF could significantly restore lumbar function, promote postoperative fusion, reduce Cage displacement and vertebral slippage, accelerate recovery of lumbar intervertebral space, and improve patient quality of life.

Introduction

Lumbar degenerative disease (LDD) refers to a disease in which the tissue structure of the lumbar spine naturally ages and undergoes degeneration, including degenerative lumbar disc herniation, lumbar spinal stenosis, lumbar spondylolisthesis, etc. The main clinical manifestations of LDD are low-back pain or lumbocrural pain [1]. The pathogenic factors of LDD are mainly related to excessive pressure and imbalance of the lumbar spine. The degenerative diseases of the lumbar spine, such as the fibrous ring, intervertebral disc nucleus pulposus, cartilage endplate, lumbar vertebral body, and ligamentum flavum, induce bone hyperplasia and lead to degenerative diseases of the lumbar spine, which are more common in middle-aged and elderly people [2]. According to statistics, a total of 266 million people (3.63%) worldwide were found to suffer from LDDs every year, which led to spinal stenosis, lumbar disc herniation, and degenerative scoliosis in the long term, further affecting neurological function [3]. Conservative treatment is the main clinical treatment for LDDs, and surgical treatment can be performed for critically ill patients with ineffective conservative treatment, spinal instability or slippage, nerve compression symptoms, and persistent back pain and leg pain [4].

Posterior lumbar interbody fusion (LIF) is a classic surgical method for treating degenerative lumbar spine diseases, which can provide appropriate nerve root decompression and restoration of intervertebral space height for the anterior column of the spine [5]. Although posterior LIF can achieve permanent stability during the fusion stage, adjacent segments can easily accelerate lumbar degeneration and even lead to instability of adjacent segments of the lumbar spine, including bone hyperplasia, lumbar spondylolisthesis, and lumbar disc herniation [6]. With the rapid development of technology, the application of biotechnology in degenerative spinal diseases has made rapid progress in both clinical and scientific aspects. Urist [7] first proposed in 1965 that bone morphogenetic protein (BMP) has a strong osteogenic induction effect. Human Recombinant Bone Morphogenetic Protein-2 (RhBMP-2) is a bone repair material with a strong osteogenic induction effect, widely used in various orthopedic diseases, and can promote bone repair [8]. The rhBMP-2 bone repair material is composed of medicinal gelatin, hydroxyapatite, and soy phospholipids. After Cage implantation, the body’s rejection response is weak. rhBMP-2 has both good toughness and strength, which can serve as a scaffold material to exert its bone conduction effect [9]. In the past, RhBMP-2 has been mainly used in the fusion process between precursors in clinical practice. However, its application in spinal surgery has been proven to achieve higher fusion rates when used in conjunction with transplanted bone [10]. However, there have been no reports of RhBMP-2 in Percutaneous Endoscopic Posterior Lumbar Interbody Fusion (PE-PLIF).

In this study, the patients with lumbar spondylosis who underwent PE-PLIF at our hospital were picked as our subjects. By observing changes in lumbar spine function, fusion rate, intervertebral space height, etc., the application of RhBMP-2 in PE-PLIF was analyzed, providing a certain reference for the treatment of clinical lumbar spine diseases.

Materials and methods

General materials

Up to 102 patients with lumbar spondylosis who underwent PE-PLIF at our hospital from April 2020 to August 2022 were randomly picked for the retrospective analysis. Following the random number table method, these subjects were graded as a study group of 51 cases (16 males and 35 females, with an average age of 54.94 ± 9.12) and a control group of 51 cases (19 males and 32 females, with an average age of 52.62 ± 7.33). The general information between the two groups had no significant difference (P > 0.05). This study was ratified by the hospital Ethics Committee (approval number: 2023-09-07). Inclusion criteria: (1) All subjects were confirmed to have lumbar spondylosis through imaging technique; (2) All subjects met the indications for LIF surgery [11] (accompanied by any of the following (≥ 1), i.e. received fusion surgery: accompanied by lumbar instability, lumbar spinal stenosis, isthmus fissure, lumbar spondylolisthesis, combined with cauda equina syndrome, combined with foot drop, aged > 60 years old, L5/S1 extreme lateral intervertebral disc herniation, with a vertex of degenerative scoliosis greater than 30 °); (3) Informed consent and signature confirmation were obtained from patients and their families. Exclusion criteria: (1) Patients with congenital lumbar spine disease; (2) Patients who could not be fully followed up; (3) Patients with severe liver, kidney, or heart dysfunction; (4) Patients with combined osteoporosis.

Methods

The control group: The patients received posterior pedicle screw fixation treatment with autologous bone. The patients were placed in a prone position and received general anesthesia. Perform right internal jugular vein puncture and catheterization, and monitor central venous pressure. Hemodynamic was maintained stable during surgery, EEG bispectral index was maintained at 45–55, and the body temperature was maintained at 36–37 °C. The left retroperitoneal intervertebral disc was exposed horizontally. The C-arm was used to obtain the true posterior-anterior view of each vertebral body in the fusion structure and determine the needle insertion site. The puncture needle was inserted into a 20 mm deep pedicle and the position of the needle tip in the intervertebral space of the pedicle was recorded. A guide wire was inserted and the intervertebral foramen was enlarged. The unstable nucleus pulposus and cartilage endplate in the intervertebral space were removed. An appropriate amount of autologous bone was taken through a circular saw drill at the posterior superior iliac spine. After being implanted into the intervertebral space, and compacted with a suitable intervertebral fusion cage (Cage), the implantation position of autologous bone was further confirmed through imaging technology. Part of the lamina, articular process, and other structures were removed as needed, and the nerve root canal was enlarged to fully decompress the nerve root. The diseased intervertebral disc was removed, the upper and lower endplates of the diseased intervertebral space were scraped, and autologous or allogeneic bone fragments and partially decompressed bone particles were implanted. The connecting rod was passed through the pedicle screw, and its position and angle were adjusted to correct lumbar spondylolisthesis, scoliosis deformity, etc. Tighten the nut of the connecting rod and fix the pedicle screw. The wound was then irrigated, a drainage tube was placed, and the fascia, subcutaneous tissue, and skin were sutured layer by layer.

The study group: The surgical incision site was determined based on preoperative planning and intraoperative X-ray fluoroscopy images, including four pedicle screw incisions, a total endoscopic surgical incision through the intervertebral space, and a lateral posterior intervertebral fusion approach incision. Disinfection and sterile surgical towels were performed routinely. A translaminar approach channel was placed and confirmed by fluoroscopy to be in the correct position. Under endoscopy, ipsilateral L5 inferior articular process and most of the bone on the medial side of the S1 joint were removed, and the ligamentum flavum tissue in the intervertebral space was exposed. The ligamentum flavum was cut open from the center outward to expose the dural sac, nerve roots, and other tissues in the spinal canal, and the protruding intervertebral disc tissue was removed. A full endoscopic working tube was used to protect the lingual end of the nerve root, and the ipsilateral Kambin triangle area was monitored under full endoscopy. The guide needle, expander, and protective sheath were sequentially implanted into the fibrous ring of the Kambin triangle through the fusion device implantation channel. Instruments such as circular rotatable bone files, circular curettes, and nucleus pulposus forceps were sequentially used to remove the nucleus pulposus tissue and cartilage endplate tissue from the intervertebral disc. Then, an endplate scraper and expandable endplate processor were employed to scrape off the cartilage endplate, expose the bone endplate, and prepare the intervertebral bone graft bed. A bone graft cannula was placed through the fusion device implantation channel, and the autologous bone and rh-BMP2 2 mg were mixed to form bone mud and filled into the vertebral space. The guide wires were placed along the fusion device implantation channel and the bone graft sleeve was removed. The fusion device was inserted into the intervertebral space and the size of the fusion device was valued. Then, the fusion cage filled with autologous bone and rh-BMP2 was implanted into the center of the intervertebral space along the guide wire. Using a percutaneous pedicle screw system, implanted under X-ray fluoroscopy guidance or navigation system guidance. The surgical incision was closed using intradermal cosmetic sutures and covered with sterile dressings. The surgical process was conducted with strict adherence to aseptic principles and the patient’s vital signs were closely monitored.

The X-ray film was used to observe whether there was a bone beam bridging through the intervertebral space. Fusion was usually considered to be in progress or successful when the X-ray was blurry with no radiolucent band and there was a bony girder bridging. Lateral lumbar radiographs were taken, and the change in the position of the marker line on the posterior edge of the Cage relative to the first postoperative measurement was measured. If the position of the marker line of the posterior edge of the Cage moved more than a certain distance (such as 3 mm) from the first measurement after an operation, the Cage was judged to be displaced.

Outcome measures

Surgical situation: the hospitalization time, surgical time, bleeding volume, and incidence of complications for two groups of patients, including incision infection, postoperative bleeding, hematoma, fusion failure, and loosening of internal fixation were recorded.

Operation: The length of hospital stay, surgical time, bleeding volume, and incidence of complications, including incisional infection, postoperative bleeding, hematoma, fusion failure and loosening of internal fixation, were recorded in the two groups.

Lumbar spine function: The lumbar spine function of patients before surgery, and 1 month and 12 months after surgery was evaluated using the Prolo score and the Japanese Orthopaedic Association (JOA) score [12]. The Prolo score [13] included two aspects: economic status and functional status, with each aspect scoring 1–5 points and a total score of 2–10 points. A higher score indicated a milder patient injury and better lumbar spine function. The JOA score included 8 items, including low back pain, combined or numbness, gait and walking ability, and daily activity limitations, with a total score of 29 points. A higher score indicated better lumbar spine function of the patient.

Postoperative fusion rate and Cage displacement rate: Patients were followed up for 12 months, and their fusion rate and Cage displacement rate were determined by X-ray examination at 1 month and 12 months after surgery.

Degree of vertebral body slippage and intervertebral space height: X-ray examinations before and 12 months after surgery were conducted to determine the degree of vertebral body slippage and changes in intervertebral space height in patients.

Quality of Life: The Health-Related Quality of Life Scale-36 (SF-36) [14] was applied to evaluate the quality of life of patients before and 12 months after the surgery, including 11 items in four parts: cognitive function, social function, physiological function, and mental health. The total score for each part was 100 points, and the score was proportional to the quality of life.

Statistic analysis

In this study, SPSS 22.0 software was used for statistical data analysis. Enumeration data including gender, fusion rate, and Cage shift rate, were exhibited in [cases (%)] and compared using χ ² test. Measurement data, including the Prolo score, JOA score, degree of vertebral slippage, intervertebral space height, SF-36 score, etc., were all presented in the form of (‾x ± s). Independent sample t-tests were used for the quantitative data between the two groups. In this study, statistical results P < 0.05 were considered as statistically significant differences.

Results

Comparison of surgical outcomes and perioperative complications between two groups

The two groups had no statistically significant difference in hospital stay, surgical time, bleeding volume, and incidence of complications between the two groups (P > 0.05, Table 1).

Table 1 Comparison of surgical outcomes and perioperative complications between two groups (‾x ± s, %)

Changes in lumbar spine dysfunction before and after surgery in two groups

Before surgery, the two groups had no significant difference in Prolo score and JOA score (P > 0.05); After 1 month and 12 months of surgery, the Prolo score and JOA score of both groups significantly increased, which were significantly higher in RhBMP-2 group than the control (P < 0.001, Table 2; Fig. 1).

Table 2 Changes in lumbar spine dysfunction before and after surgery in two groups (‾x ± s)

Fig. 1

Comparison of lumbar spine dysfunction analysis between two groups before surgery, and 1 month and 12 months after surgery. A: Comparison of Prolo scores among three groups; B: Comparison of JOA scores among three groups. Note: ^***P < 0.001 compared with the same group before surgery, and ^###P < 0.001 compared with the control group 12 months after surgery

Changes in postoperative fusion rate and cage displacement rate in two groups

The pre - and post-operative radiographs of the patients in the study group were shown in Fig. 2. Figure 2A showed obvious degenerative changes in the height of the lumbar intervertebral space and the morphology of the vertebral body. The bone mineral density of the fused segment increased, the trabecular structure was clear, and the internal fixation was good in Fig. 2B. One month post-operation, the fusion rate and Cage displacement rates were 9.80% and 1.96% in the RhBMP-2 group respectively, while were 0.00% and 5.88% in the control group respectively (P > 0.05). 12 months post-operation, the fusion rate in the RhBMP-2 group was 86.27%, which was significantly higher than that of 54.90% in the control group (P < 0.05). 12 months post-operation, the Cage displacement rate in the RhBMP-2 group was 5.88%, which was lower than that of 21.57% in the control group (P < 0.05, Table 3).

Fig. 2

Pre - and post-operative radiographs of the patients in the study group. A: Preoperative X-ray; B: X-ray at 12 months after surgery

Table 3 Changes in postoperative fusion rate and cage displacement rate in two groups of patients [cases (%)]

Changes in the degree of vertebral slippage and intervertebral space height before and after surgery in two groups

Before the operation, the two groups had similar intervertebral space height and degree of vertebral slippage (P > 0.05). At 12 months post-operation, the height of the intervertebral space in both groups significantly increased, which was significantly higher in the RhBMP-2 group than in the control group (P < 0.05). The degree of vertebral body slippage was significantly reduced and was much lower in the RhBMP-2 group than in the control (P < 0.001, Table 4; Fig. 3).

Table 4 Changes in the degree of vertebral slippage and intervertebral space height before and after surgery in two groups (‾x ± s)

Fig. 3

Analysis of changes in vertebral body slippage degree and intervertebral space height before and 12 months after surgery in two groups. A: Comparison of intervertebral space heights between two groups; B: Comparison of the degree of vertebral body slippage between two groups. Note: ^***P < 0.001 compared with the same group before surgery, and ^###P < 0.001 compared with the control group 12 months after surgery

Analysis of quality of life before and after surgery in two groups

The two groups had no significant difference in cognitive function, social function, physiological function, and mental health Before the operation (P > 0.05). At 12 months post-operation, cognitive function, social function, physiological function, and mental health were significantly improved in both groups, which were significantly higher in the RhBMP-2 group than in the control (P < 0.001, Tables 5 and 6, and Fig. 4).

Table 5 Comparison of cognitive function and social function between two groups before and after surgery (‾x ± s)

Table 6 Comparison of physiological function and mental health between two groups before and after surgery (‾x ± s)

Fig. 4

Comparison of quality of life between two groups before and after surgery. A: Comparison of cognitive function scores between two groups; B: Comparison of social function scores between two groups; C: Comparison of physiological function scores between two groups; D: Comparison of psychological health scores between two groups; Note: P < 0.001 compared to the same group before surgery, and P < 0.001 compared to the control group 12 months after surgery. Note^***P < 0.001 compared with the same group before surgery, and ^###P < 0.001 compared with the control group 12 months after surgery

Discussion

With the continuous development of LIF surgery, minimally invasive transforaminal LIF surgery, PE-PLIF, and dual channel endoscopic LIF surgery have been formulated. Compared with traditional open surgery, they have obvious advantages in terms of trauma, bleeding volume, and postoperative recovery [15]. Research has found [16] that compared to other methods, PE-PLIF can achieve higher decompression of nerve roots and spinal canal, and better results. However, fusion surgery may not be effective for all patients [17]. Autologous bone grafts have natural bone inductivity and bone conductivity, making them the gold standard in bone transplant materials. However, due to its limited sources and drawbacks such as pain at the bone extraction site, the development of new bone repair materials has become an urgent problem to be solved.

With the continuous deepening of research, it has been found that autologous bone can more effectively promote local bone formation and is less prone to rejection reactions, but it is difficult to find suitable autologous bone. Bone morphogenetic protein (BMP) is currently internationally recognized as the only local growth factor that can induce bone tissue formation and repair hard tissue. Among them, BMP-2 is one of the strongest osteogenic-inducing factors in the BMPs family, which can induce undifferentiated mesenchymal stem cells to differentiate and proliferate towards chondrocytes and osteoblasts. BMP-2 promotes the differentiation and maturation of osteoblasts, participates in the growth, development, and reconstruction of bone and cartilage, and accelerates the rehabilitation of bone defects [18]. BMPs are proteins extracted from a decalcified bone matrix that can selectively induce mesenchymal cells to differentiate into osteoblasts and induce cartilage and bone ectopic differentiation [19]. In this study, RhBMP-2 was applied in PE-PLIF. The results showed that postoperative RhBMP-2 group patients had significantly higher Prolo and JOA scores than the control. Thus, RhBMP-2 was believed to improve lumbar spine function in patients and play a major role in improving the quality of life. Similar to relevant research findings [20], this study suggested that RhBMP-2 could effectively reduce patient pain levels and achieve good clinical outcomes in the treatment of thoracolumbar fusion. Meanwhile, animal models of spinal fusion research have shown that the application of rhBMP-2 induced significant differences in the expression of cytokines throughout the fusion process. Among them, IL-6 and IL-1RA were highly expressed, while growth factor expression seemed to be inhibited. Elevated IL-6 might be the cause of rhBMP-2-induced formation of new bone and excess adipose tissue in bone gaps [21].

Lee et al. [22] compared the postoperative imaging results and clinical outcomes between the rhBMP-2 group and the multipotent adult progenitor cell (map3) group and found that the incidence of complications in the rhBMP-2 group was higher than that in the map3 group. Esmail et al. [23] retrospectively analyzed the frequency of complications in patients undergoing posterior/lateral lumbar fusion surgery and found that the rhBMP-2 group had a higher incidence of complications. They also found that rhBMP-2-related complications might be gender-related. Weisbrod et al. [24] studied the imaging data of 26 patients who underwent cervical fusion surgery and observed the characteristic manifestations of rhBMP-2 (pre-vertebral soft tissue swelling and early endplate resorption) in all patients. They also found imaging manifestations such as polyetheretherketone cage settlement, displacement, and ectopic bone formation. Analyzing the reasons, it was of great significance for a postoperative fusion of higher bone grafting materials to restore spinal stability and reduce the compression of intervertebral discs on nerve roots. However, the results of this study showed that there was no significant difference in hospitalization time, surgical time, bleeding volume, and incidence of complications between the two groups. The analysis might be related to the small sample size and short follow-up time of this study, and there might exist bias in the results.

BMPs exert their effects by binding to serine/threonine receptors, increasing levels of alkaline phosphatase and parathyroid hormone, thereby increasing the expression of osteocalcin. When combined with transmembrane receptors on mesenchymal stem cells, BMPs induce their differentiation into osteoprogenitor cells and form new bone [25]. In recent years, RhBMP-2 has been an ideal substitute for autologous bone transplantation materials. RhBMP-2 has osteogenic induction characteristics similar to BMP-2. At the same time, rhBMP-2 has the characteristics of early induction of bone formation, high bone mass, and good biological activity and biocompatibility [26]. The results of the present study exhibited that compared with the control group, the RhBMP-2 group had significantly higher fusion rate, a significantly lower Cage displacement rate, an obviously higher intervertebral space height, and an evidently lower degree of slippage, indicating that rhBMP-2 had a promoting effect on bone graft fusion. Consistent with relevant research findings, this study suggested [27] that RhBMP-2 had a higher fusion rate for posterior lateral spinal fusion compared to autologous bone transplantation. Analyzing the relevant reasons, the high fusion rate after using RhBMP-2 bone grafting material indicated that RhBMP-2 could cause higher local bone resorption in the final bone plate. RhBMP-2 could increase the rate of bone fusion in a short time, providing a relatively stable support for the spine, thereby reducing cage displacement and achieving a good vertebral reduction effect. RhBMP-2 maintained the overall stability of the lumbar spine structure, which was beneficial for rapid postoperative recovery and thus improved the quality of life of patients. The reasons for the low fusion rate in the control group may be improper surgical operation, insufficient screw inclination, repeated nail placement, spine-pelvic parameter mismatch, etc., which can increase the risk of internal fixation failure and further affect the fusion rate. In addition, the amount of bone graft is one of the important factors affecting the fusion rate, and the limited amount of autologous bone may not meet the needs of patients who need a large amount of bone graft. If the amount of bone graft is insufficient, the fusion effect may be poor [28].

X-rays are a common method for evaluating fractures and fusions, but they may not be sensitive enough to accurately show fusions in some cases, and may not provide sufficient information for complex anatomical structures or subtle changes [29]. Although CT scanning has a higher resolution, in some cases, such as the presence of metal implants, artifacts may occur that affect the accuracy of the assessment [30]. In addition, different types of implants have different effects on fusion evaluation. Titanium metal has good biocompatibility and mechanical properties, but it may produce artifacts in imaging evaluation, affecting the accuracy of evaluation. The elastic modulus of the PEEK cage is similar to that of bone, which is conducive to reducing the stress shielding effect and promoting fusion [31]. Therefore, when evaluating the postoperative fusion rate of patients, it is necessary to comprehensively consider the limitations of imaging evaluation, diagnostic basis such as symptoms and implant failure, as well as the influence of implant type on fusion evaluation. Relevant data [32] suggest that there might be no statistically significant difference in the fusion rate between unilateral two-channel endoscopic lumbar interbody fusion (ULIF) and open PLIF, suggesting that both are effective in promoting interbody fusion. However, endoscopic technology, due to its advantages of less trauma, less bleeding volume, and faster postoperative recovery, might be beneficial to the smooth progress of the fusion process to some extent, although such advantages may not be obvious in the fusion rate [33]. Both endoscopic technology and open PLIF rely on imaging methods, such as X-rays and CT scans, to evaluate fusion. However, these methods have certain limitations in evaluating fusion, such as artifact generation and evaluator subjectivity, especially for endoscopic technology, due to the low surgical trauma and small implant size, Imaging assessment may be more difficult [34]. The fusion process involves a variety of biological factors, such as bone healing ability, inflammatory response, angiogenesis, etc. The complexity of these factors makes the fusion process difficult to predict and control [35]. With the continuous development of endoscopic technology, new surgical instruments, imaging techniques, and surgical methods continue to emerge, providing more possibilities for improving the fusion process, such as the use of high-resolution imaging systems, new biological materials, and intelligent surgical navigation systems, which can further improve the accuracy and safety of surgery, so as to facilitate the smooth progress of the fusion process.

In general, RhBMP-2 material in PE-PLIF could significantly restore lumbar function, promote postoperative fusion, reduce Cage displacement and vertebral slippage, accelerate recovery of lumbar intervertebral space, and improve patient quality of life. However, this study still had certain limitations. Long-term observation has higher clinical application value than short-term observation in the indicators of the postoperative fusion rate, Cage displacement rate, quality of life, and others. Moreover, the long-term effects and adverse reactions of RhBMP-2 in patients are still unclear. Thus, it is necessary to expand the sample size and extend the follow-up time to further confirm the accuracy of the results and the occurrence of adverse reactions, so as to better provide relevant theoretical references for the therapy of lumbar spine diseases in the later stage.

The innovation of the research.

Innovation in material applications: RhBMP-2: As a potent osteo-inductive cytokine, RhBMP-2 has been widely used in spinal fusion surgery. This study, which combines RhBMP-2 with PE-PLIF, aims to improve the success rate of the fused segment by local application of RhBMP-2 to promote osteo-induced growth. This innovation in material application may not only reduce the need for autologous bone grafting and the complications associated with bone harvesting surgery, but may also shorten the operation time and postoperative recovery period.

Innovation of research methods: Comprehensive evaluation and comparative analysis: This study may evaluate the efficacy of RhBMP-2 in PE-PLIF through comparative studies. The safety and efficacy of RhBMP-2 in this procedure were comprehensively evaluated by comparing the imaging results, clinical efficacy, and complication rate of patients with and without RhBMP-2 use. This research method of comprehensive evaluation and comparative analysis is helpful to reveal the mechanism and application value of RhBMP-2 in spinal fusion more accurately.

Innovation in the prospect of clinical application: Promotion in the process of minimally invasive spine surgery: The successful implementation of this study is expected to promote the development of minimally invasive spine surgery. To improve the therapeutic effect of spinal fusion by optimizing surgical techniques and materials, reduce surgical risks and complications, and provide patients with safer and more effective treatment options.