The objective of the study was to evaluate our innovative percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) for the treatment of lumbar degenerative diseases. Two fresh-frozen human cadavers with soft tissues were donated for the experiment. Both cadavers had no history of previous spine surgery. The PE-TLIF surgery was performed on 3 levels (L4-5 of the first one, and L3-4, L4-5 of the second one) in October 2015. The PE-TLIF technique mainly included the following aspects: primary guide pins and a specially designed superior articular process (SAP) guide insertion, working channel setup, endoscopic decompression and fusion, and pedicle screw implantation and fixation. Under the surveillance of C-arm fluoroscope, four primary guide pins were inserted. The inferior primary guide in the hypothetically symptomatic side was confirmed as the first guide pin. At the end of the first guide pin, the specially designed SAP guide was installed. The secondary guide pin was inserted in the SAP via self-designed SAP guide. Under the protection cannula, part of the superior articular process was removed by oriented SAP resection device, so the working channel was smoothly put through the Kambin’s triangle. The endoscope was inserted close to the exiting nerve root. Rotation of the working channel kept the nerve root out of it. Three levels of PE-TLIF were successfully performed in two cadavers. Self-designed SAP guide made the secondary guide pin inserting the SAP accurately. Decompression was adequate and the traversing nerve root was relieved. Three aimed intervertebral levels are implanted with two 7-mm-high PEEK cages and one expandable cage. The expandable cage could be adjusted from 8 mm to 13 mm. Surgical incisions included four 15 mm incisions for percutaneous screw fixation and one 12 mm incision for working channel. There was no nerve injury during the operations. Our present results showed that the novel minimally invasive surgery PE-TLIF was feasible for the treatment of lumbar degenerative diseases.

The mismatch in the pedicle screw/rod interface angle is a common phenomenon after topping-off surgery, indicating that the implants were assembled under mechanical stress, which may negatively impact clinical outcomes. This study aims to assess the incidence of postoperative screw/rod mismatch and its effect on clinical outcomes, including (1) Adjacent segment degeneration (ASD); (2) Screw loosening and rod breakage; (3) Visual analogue scale (VAS) scores; and (4) Oswestry disability index (ODI) scores. This study is a monocentric retrospective observational study that included patients diagnosed with lumbosacral degenerative disease and underwent topping-off surgery. The outcome measures encompass: interfacing angle mismatch between pedicle screws and support rods, incidence of proximal ASD, screw loosening and rod breakage, VAS scores, and ODI scores. The impact of screw–rod interfacing angle mismatch on the development of postoperative ASD was further analyzed using univariate and multivariate logistic regression analysis. Postoperatively, lateral X-rays and CT scans were used for measurements. The interfacing angle mismatch between the pedicle screw and rod is measured as the angle between two parallel lines on either side of each pedicle screw head and a line laterally along the associated rod. Bonferroni correction was applied to counteract multiple comparisons, with the adjusted significance level set at *p < 0.05. Among the 237 patients who underwent topping-off surgery, 84 cases (35.44%) exhibited a mismatch in the interfacing angle between the pedicle screw and the support rod, involving 114 out of 1,208 screws (9.44%). After a mean follow-up period of 26.57 ± 2.88 months, the overall incidence of adjacent segment degeneration (ASD) was 9.28% (22/237), screw loosening occurred in 12.66% of patients (30/237), and rod breakage occurred in 2.53% (6/237).In patients with interfacing angle mismatch, the incidence of ASD was significantly higher, reaching 21.4% (18/84), compared to 2.6% (4/153) in patients without mismatch (P < 0.001). The increase in screw loosening was even more pronounced, with a rate of 28.6% (24/84) in the mismatch group versus only 3.9% (6/153) in the matched group (P < 0.001).There was no significant difference in rod breakage rates between the two groups (2.0% vs. 3.6%, P = 0.361). Additionally, patients with angle mismatch had significantly higher VAS scores than those without mismatch (3.63 ± 0.93 vs. 2.19 ± 0.78, P < 0.001). However, there was no statistically significant difference in ODI scores between the two groups (19.26 ± 2.51 vs. 19.70 ± 2.62, P = 0.214). A mismatch in the interfacing angle between the pedicle screw and the support rod may contribute to a higher incidence of ASD, increased screw loosening, and more severe postoperative pain following topping-off surgery. Refined preoperative planning of screw trajectories and precise intraoperative techniques are essential to optimize clinical outcomes and reduce the risk of ASD.

Introduction: Herniations of the intervertebral disc into the vertebral body, known as Schmorl’s nodes (SNs), are frequently associated with degenerative disc disease (DDD). Painful SNs can contribute to discogenic lower back pain associated with DDD. Studies show that percutaneous endoscopic lumbar discectomy (PELD) yields favorable treatment outcomes for degenerative spinal diseases. This study retrospectively evaluated the efficacy of PELD in treating painful SNs. Objective: To evaluate the clinical efficacy and safety of PELD in treating patients with painful SNs. Methods: From February 1, 2020, to February 1, 2023, 13 patients with discogenic back pain from painful SNs (confirmed via intraoperative discography) who underwent single-level PELD at the index SN level were enrolled in the current study. Clinical data were retrospectively analyzed. Outcome measures, including the visual analog scale (VAS) for back pain and the Oswestry Disability Index (ODI), were recorded preoperatively and at 1 day, 6 months, and 12 months postoperatively. MRI scans of the lumbar region for all patients were evaluated preoperatively and again at the one-month follow-up. Results: All 13 patients were successfully treated with percutaneous endoscopic lumbar discectomy (PELD), showing significant postoperative improvements in VAS and ODI scores. Postoperative lumbar MRI revealed degenerative disc material in the SN cavities, which was removed using PELD. No surgical issues such as infections or nerve root damage, were noted. Conclusion: Postoperative MRI confirmed the removal of degenerative disc material, reinforcing PELD’s efficacy in treating the pathological changes associated with painful SNs. No surgical complications, such as infections or nerve root damage, were seen, underscoring the safety of PELD. This study demonstrates that PELD effectively manages discogenic lower back pain caused by SNs. Plain Language Summary: New knowledge added by this studyThis study presents preliminary evidence supporting a minimally invasive surgery called PELD for painful Schmorl’s nodes.By using postoperative MRI, this study is the first to confirm that the damaged disc material can be removed through this method.The study also provides early evidence of symptom relief lasting up to 27 months. Implications for clinical practice or policyPELD may be a safe and effective option for patients with Schmorl’s node-related back pain who do not improve with other treatments.MRI and discography can help identify patients who may benefit from this approach.These findings may support wider use of PELD and reduce the need for open surgery in select cases.