Comparative study on the clinical efficacy and safety of MIS-TLIF versus PELD surgery for the treatment of recurrent lumbar disc herniation

Technical Summary: Comparative Study on MIS-TLIF versus PELD for Recurrent Lumbar Disc Herniation

Problem Statement
Recurrent lumbar disc herniation (RLDH) following a primary surgery remains a significant clinical challenge. While minimally invasive techniques have become the standard for initial treatment, postoperative recurrence rates range from 0.5% to 21%. Revision surgery for RLDH is particularly difficult due to scar tissue adhesion, obscured anatomical landmarks, and an elevated risk of nerve root or dural injury. The optimal surgical strategy for revision—specifically whether to perform a fusion procedure or a repeat non-fusion discectomy—remains a subject of debate. This study addresses the need to compare the clinical efficacy and safety of two distinct minimally invasive approaches: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) and Percutaneous Endoscopic Lumbar Discectomy (PELD) in patients experiencing RLDH after a primary PELD procedure.

Methodology
The study employed a retrospective cohort design involving 71 patients diagnosed with RLDH following a primary PELD procedure, treated at Tangdu Hospital between January 2015 and January 2023.

• Cohort: Patients were divided into two groups: the MIS-TLIF group (n=46) and the PELD group (n=25). Note: While the abstract initially mentions 31 patients in the PELD group, the Results section and Table 1 clarify the final analyzed cohort as 25 patients in the PELD group.
• Inclusion Criteria: Single-level lumbar disc herniation treated initially with PELD, symptom relief for at least one month post-index surgery, confirmed recurrence at the same level with nerve root compression, failure of conservative management (>6 weeks), and complete imaging/follow-up data.
• Exclusion Criteria: Other spinal pathologies (stenosis, tumor, fracture), systemic conditions affecting bone metabolism, or surgical contraindications.
• Surgical Techniques:
  • MIS-TLIF: Performed under general anesthesia using a tubular retractor system. The procedure involved partial laminectomy, facetectomy, disc excision, endplate preparation, interbody fusion with a PEEK cage and autograft, and percutaneous pedicle screw fixation.
  • PELD: Performed under general or local anesthesia depending on the level (interlaminar for L5/S1; transforaminal for L3/4 and L4/5). The technique utilized endoscopic visualization to remove herniated fragments via a 7.5-mm working cannula, with specific attention to foraminal decompression if necessary.
• Outcome Measures: Perioperative parameters (operation time, blood loss, hospital stay) and clinical efficacy were assessed using Visual Analogue Scale (VAS) for back and leg pain, Japanese Orthopaedic Association (JOA) scores, Oswestry Disability Index (ODI), and the modified MacNab criteria. Follow-ups occurred at 3 months, 6 months, 1 year, and 2 years.

Key Results

• Perioperative Metrics: The PELD group demonstrated significantly superior perioperative outcomes compared to the MIS-TLIF group, including shorter operation times (79.8 vs. 201.4 min), less intraoperative blood loss (median 20 mL vs. 200 mL), and shorter hospital stays (2.8 vs. 5.6 days) (P < 0.001).
• Clinical Efficacy: Both groups showed significant improvement from baseline in all pain and functional scores at all follow-up points.
  • Short-term: At 3 months, the ODI score was significantly lower (better) in the MIS-TLIF group compared to the PELD group (P < 0.001).
  • Long-term: At the 2-year follow-up, the MIS-TLIF group demonstrated significantly superior outcomes in back pain VAS, leg pain VAS, JOA scores, and ODI scores compared to the PELD group (P < 0.05 for VAS; P < 0.001 for ODI and JOA).
  • Patient Satisfaction: The modified MacNab criteria at 2 years showed a significantly higher rate of "excellent or good" outcomes in the MIS-TLIF group (100%) compared to the PELD group (84%) (P < 0.001).
• Complications and Recurrence:
  • The MIS-TLIF group had a 6.5% complication rate (CSF leak, nerve root injury, infection), all of which resolved.
  • The PELD group had no intraoperative complications but experienced a same-level recurrence rate of 8% (2 patients), both of whom underwent successful revision via MIS-TLIF.
  • The difference in overall complication and recurrence rates between the two groups was not statistically significant.

Key Contributions
This study provides a direct comparative analysis of two minimally invasive strategies for a specific, challenging patient subgroup: those with RLDH following a failed primary PELD.

1. Differentiation of Indications: The data suggests that while PELD offers distinct advantages in terms of reduced invasiveness and faster immediate recovery, MIS-TLIF yields superior medium-to-long-term functional outcomes and patient satisfaction for this specific population.
2. Evidence for Revision Strategy: The study contributes evidence that fusion (MIS-TLIF) may be more durable for RLDH after failed endoscopic discectomy, potentially due to the ability to address segmental instability and perform more thorough decompression and adhesiolysis compared to repeat endoscopic discectomy.
3. Safety Profile: The study confirms that both procedures are safe, with no statistically significant difference in overall complication rates, despite the theoretical risks associated with fusion instrumentation.

Significance and Claims
The authors conclude that both MIS-TLIF and PELD are safe and effective options for managing RLDH after a failed primary PELD, but they serve distinct roles based on patient characteristics and clinical goals.

• PELD is presented as a viable option for low-risk patients who prioritize minimal invasiveness, have no segmental instability, and do not engage in heavy manual labor. It is characterized by less blood loss, shorter operation time, and faster recovery.
• MIS-TLIF is identified as providing superior medium-to-long-term clinical effects and higher patient satisfaction, making it the preferred strategy for complex cases, patients with biomechanical instability, or those requiring durable functional restoration.

The paper emphasizes that the choice of procedure must be individualized, balancing imaging characteristics, clinical presentation, functional expectations, and patient preference. The authors acknowledge limitations, including the retrospective nature of the study, the relatively small sample size (particularly in the PELD group), and the medium-term follow-up period, suggesting that larger prospective studies are needed to confirm these findings.