A Novel Minimally Invasive Technique for the Treatment of High-grade Isthmic Spondylolisthesis Using a Posterior Transsacral Rod
Bibliographic record
Abstract
STUDY DESIGN: Case report of 3 patients with high-grade isthmic spondylolisthesis treated using a novel minimally invasive technique using a posterior transsacral rod. OBJECTIVE: To assess the efficacy, safety, and advantages of this approach in the treatment of high-grade L5-S1 spondylolisthesis. SUMMARY OF BACKGROUND DATA: Surgical treatment of high-grade isthmic spondylolisthesis at the L5-S1 level is technically demanding. The most commonly used procedure is posterior spinal fusion. In this report, we present a new minimally invasive technique for the treatment high-grade isthmic spondylolisthesis in 3 patients with sagittally balanced spines. MATERIALS AND METHODS: Three patients with high-grade L5-S1 spondylolisthesis underwent L4-S1 fusion with percutaneous pedicle screw fixation supplemented with a transsacral rod implanted through a tubular retractor. We report technical details, clinical, and radiologic results at follow-up. RESULTS: All 3 patients suffered from grade 3 or 4 L5-S1 spondylolisthesis. All patients had neutral sagittal balance on preoperative imaging. There were no postoperative complications and all 3 patients were discharged within 48 hours. At final follow-up (range, 13-18 mo), all patients were pain free off all narcotic pain medication and fusion was observed in all 3 patients. CONCLUSIONS: We have shown the technical feasibility of anterior and posterior fusion for severe L5-S1 spondylolisthesis using a minimally invasive percutaneous technique through a transsacral approach. The main advantage of a posterior transsacral axial rod fixation is that it creates a structurally sound anterior column support, thus eliminating the problems related to bone grafts and eliminating the complications associated with an anterior approach. Our preliminary results suggest that this technique is feasible and seems to be associated with favorable outcome, although larger studies are warranted to verify these findings.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".