Purpose <p>Upper lumbar disc herniations (L1–2, L2–3) present unique anatomical challenges due to narrow interlaminar windows and facet joint proximity. This pilot feasibility study aimed to evaluate the safety and short-term efficacy of a novel minimally invasive tubular trans-isthmus oblique approach for upper lumbar disc herniation, prior to a planned prospective trial.</p> Methods <p>Twenty patients (13 males, 7 females; mean age 50.8 years) with imaging-confirmed L1–2 or L2–3 paracentral disc herniation and unilateral leg pain unresponsive to conservative management were enrolled between January 2022 and January 2024. All underwent decompression using the novel tubular trans-isthmus oblique approach designed to preserve the medial facet cortex. Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for leg pain were assessed preoperatively and at 1, 3, 6, and 12 months. Modified Macnab criteria were recorded at 12 months. Dynamic radiographs and postoperative CT (in selected cases) assessed stability and facet preservation. Statistical analysis was performed using JASP v0.18 with Wilcoxon Signed Rank Test and Friedman test.</p> Results <p>Median preoperative ODI was 83%, improving to 5% at 3 months (<i>p</i> &lt; 0.001). VAS leg pain scores improved from a mean of 8.24 to 1, 0, and 0 at 1, 3, and 12 months respectively (<i>p</i> &lt; 0.01). Seventeen patients had excellent outcomes, 2 good, and 1 fair per Macnab criteria. No recurrence or radiological instability was observed. One dural tear and one transient L2 dysesthesia resolved without sequelae.</p> Conclusion <p>To the best of our knowledge, this is the first clinical study to describe and evaluate a minimally invasive tubular trans-isthmus oblique approach for upper lumbar disc herniation. The technique appears technically feasible and safe. These encouraging results support the need for larger prospective trials to confirm long-term outcomes and reproducibility.</p>