[Deep Dural Suturing and Multilayer Skull Base Reconstruction].

This review described the principles and techniques of dural suturing and multilayer skull base reconstruction in extended endoscopic endonasal surgery, with an emphasis on the Japanese tradition of deep suturing. Secure watertight reconstruction is a fundamental requirement in extended transsphenoidal and endonasal skull base surgery because persistent cerebrospinal fluid (CSF) leakage can result in life-threatening meningitis. Since its introduction in 2007, multilayer reconstruction using various materials combined with a pedicled nasoseptal flap has become the standard approach. In contrast, Japanese surgeons had long emphasized direct dural closure using deep suturing techniques, even before the widespread adoption of endoscopy. This culture of suturing has been incorporated into modern endoscopic surgery and remains a key component of skull base reconstruction in Japan. Deep suturing provides reliable fixation of patch materials, contributes to both major and minor CSF leak control, and may reduce the dependence on large vascularized flaps in selected cases. This review described the fundamental techniques of deep suturing, including needle handling, control of the needle holding angle, knot-sliding methods, and suturing in multilayer reconstruction strategies. It also discussed the management of CSF pulsation and training methods. Although technically demanding, deep suturing is a highly reliable and versatile technique that continues to play a critical role in endoscopic skull base surgery.