# Assisted full-endoscopic spine surgery for lumbar spinal stenosis: Technical note and learning curve

## TL;DR

This paper introduces a new spine surgery technique called AFESS that reduces pain and preserves joints, with a clear learning curve for surgeons.

## Contribution

AFESS combines uniportal and biportal techniques to improve decompression and facet joint preservation in lumbar spinal stenosis.

## Key findings

- Operative time decreased significantly from 99 to 72 minutes as surgeons gained experience with AFESS.
- Facet joint preservation improved from 68.9% to 76.2% in the advanced phase of the learning curve.
- AFESS achieved significant pain relief with final radicular VAS scores below 1.0 cm in both initial and advanced phases.

## Abstract

Lumbar spinal stenosis (LSS) causes disabling back and radicular pain. Full-endoscopic spine surgery offers minimally invasive decompression, but uniportal and biportal approaches have limitations. Assisted full-endoscopic spine surgery (AFESS) combines the advantages of both techniques to enhance decompression while preserving facet joints.

Can AFESS provide effective decompression with high facet preservation for LSS, and what is the learning curve for this technique?

We retrospectively reviewed 33 patients with single-level LSS treated with AFESS, divided into initial (20 cases) and advanced (13 cases) phases. Outcomes assessed at a minimum 6-month follow-up included operative time, facet joint preservation ratio, complications, and visual analog scale (VAS) scores for back and leg pain.

Operative time decreased significantly from the initial to the advanced phase (mean 99 vs 72 min; p < 0.01). Facet joints were more preserved in the advanced phase (76.2 % vs 68.9 %, p < 0.05). In the initial and advanced phases, mean lumbar VAS improved from 4.2 to 1.1 cm and 2.8 to 0.2 cm, respectively. Radicular VAS improved from 7.7 to 0.8 cm (initial) and 6.9 to 0.9 cm (advanced) (p < 0.01 for all). Two patients (6 %) experienced minor complications in the initial phase, with no permanent deficits.

AFESS is safe and effective, achieving adequate decompression with high facet preservation and significant pain relief in LSS patients. By integrating uniportal and biportal endoscopic approaches, AFESS overcomes limitations of each. The well-defined learning curve suggests it can be efficiently incorporated into clinical practice with minimal complications.

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Assisted Full-Endoscopic Spine Surgery (AFESS) is a modified biportal technique that integrates uniportal high-definition optics with independent instrument manipulation.
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The technique demonstrated a clear learning curve, with mean operative time significantly decreasing from 99 min in the initial phase to 72 min in the advanced phase.
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Facet joint preservation significantly improved from 68.9 % in the initial phase to 76.2 % in the advanced phase, achieved through inside-out decompression.
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Significant pain relief was achieved in both phases, with final mean radicular VAS scores dropping to less than 1.0 cm in both groups.
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AFESS showed a favorable safety profile with a low complication rate (6 %) and no permanent neurological deficits.

Assisted Full-Endoscopic Spine Surgery (AFESS) is a modified biportal technique that integrates uniportal high-definition optics with independent instrument manipulation.

The technique demonstrated a clear learning curve, with mean operative time significantly decreasing from 99 min in the initial phase to 72 min in the advanced phase.

Facet joint preservation significantly improved from 68.9 % in the initial phase to 76.2 % in the advanced phase, achieved through inside-out decompression.

Significant pain relief was achieved in both phases, with final mean radicular VAS scores dropping to less than 1.0 cm in both groups.

AFESS showed a favorable safety profile with a low complication rate (6 %) and no permanent neurological deficits.