Surgical Invasiveness, Hidden Blood Loss, and Outcomes of Two Endoscopic Lumbar Fusion Techniques for Degenerative Disease: A Comparative Study

The rapid advancement of spinal endoscopic techniques has underscored the need for comparative evaluations of various surgical approaches. This study compares unilateral biportal endoscopic lumbar interbody fusion (ULIF) and fully endoscopic transforaminal lumbar interbody fusion (Endo-PLIF) in the treatment of lumbar degenerative diseases (LDD), with a focus on surgical invasiveness, hidden blood loss (HBL), and clinical outcomes. A total of 120 patients diagnosed with LDD were enrolled between January 2021 and January 2024. Of these, 63 patients underwent ULIF, and 57 received Endo-PLIF. Perioperative indicators were recorded, including operative time, hospital stay, incision length, intraoperative blood loss, and changes in intervertebral disc and foraminal height.Clinical outcomes were assessed using visual analog scale (VAS) scores for back and leg pain, the Oswestry Disability Index (ODI), and the modified Macnab criteria at the final follow-up. Assessments were conducted preoperatively and at 3 days, 3 months, 6 months, and 12 months postoperatively. Fusion rates and complication incidences were also documented.Muscle injury was quantified by measuring serum levels of creatine kinase (CK) and C-reactive protein (CRP) preoperatively and on postoperative days 1, 3, and 5. Descriptive statistics and multiple comparison tests were applied to assess differences in clinical indicators between the two surgical groups. The VAS score served as the primary clinical outcome. Longitudinal data were analyzed using a generalized linear mixed model to evaluate intergroup differences over time. Baseline demographic and surgical data were comparable between the two groups. The CRP and CK levels in the Endo-PLIF group were generally lower than those in the ULIF group, particularly on postoperative day 3 for CRP and on postoperative day 1 for CK. Compared to the ULIF group, the Endo-PLIF group exhibited significantly reduced total blood loss, postoperative blood loss, and hidden blood loss. No significant difference was observed in postoperative hospital stay duration between the groups. Both groups showed improvements in VAS pain scores and ODI. A significant reduction in VAS back pain was observed on the third day after ULIF, while leg pain improved significantly at 3 days and 3 months post-surgery. At the final follow-up, no further differences in clinical outcomes were observed between the two groups. Both surgical methods resulted in significant relief of back pain and functional improvement. Although ULIF showed a distinct advantage in early postoperative pain control and functional recovery, outcomes for both techniques became comparable during long-term follow-up. However, Endo-PLIF exhibited a significant advantage in terms of reduced surgical trauma and blood loss. Overall, both methods represent viable treatment options with acceptable safety profiles. The choice of approach should be tailored to the individual patient's condition, considering the trade-offs between early recovery and surgical invasiveness.