Translaminar fully endoscopic approach for lumbar disc herniations in the hidden zone.

Minimally invasive endoscopic procedures for the treatment of lumbar disc herniations (LDHs) have gained increasing popularity among spine surgeons during the last decade. The majority of LDH cases can be effectively managed using endoscopic techniques, particularly the interlaminar or transforaminal approaches, which allow for direct decompression of the affected nerve root with reduced morbidity compared to conventional open surgery. However, when LDHs migrate cranially or caudally beyond the usual intervertebral disc space, their surgical management becomes significantly more challenging. This difficulty arises from the increased risk of postoperative instability, which is often associated with partial or total facetectomy required to achieve adequate exposure. These migrated herniations, commonly referred to as occurring in the so-called "hidden zone", represent a surgical dilemma due to their limited accessibility and the potential for increased complications. Furthermore, reports in the literature describing their management, particularly through minimally invasive endoscopic routes, remain relatively scarce. In this context, we present a detailed description of the translaminar fully endoscopic approach (TFEA) for the treatment of LDH in the hidden zone. In the authors' opinion, this approach offers a safe and effective minimally invasive alternative that minimizes anatomical disruption, preserves spinal stability, and broadens the spectrum of endoscopic spine surgery applications.