Usefulness of the knot-tightener device following dural suturing in endonasal transsphenoidal surgery: technical report.

Transsphenoidal surgery (TSS) has become a well-established standard surgical technique, but the cerebrospinal fluid leakage remains controversial. Direct suturing of the dura, which is a routine procedure within transcranial surgery, can be applied for closure of the sella turcica within TSS. However, as the dura is not accessible by the index finger, knot tying in the narrow and deep surgical corridor following dural suturing is extremely difficult, cumbersome, and time-consuming in TSS. Here, we present a new, simple, and effective technique for knot tying using our newly developed instrument the "knot tightener" (UC-6603: Medical U & A, Inc., Osaka, Japan) to solve this challenge. The knot tightener has a total length of 235 mm and is bayonet shaped. The tip is 5 × 10 mm in diameter and has one long arm and two short curved arms. The long arm has a dimple which can hook and hold a thread, fulfilling the role of an index finger. Together the two short curved arms make a half circle and are able to hook a thread easily. From the 28th of March 2011 to August 2018, we used the knot-tightener device for 566 patients who underwent endonasal TSS, to deliver and tie knots following stitching of the dura using 6-0 nylon. The device was able to easily deliver a knot from outside of the nostril to the sella turcica through the nasal cavity and successfully tighten it firmly. No complications were observed, confirming the safety of the newly designed instrument. The knot tightener can be considered to be an optimal tool for the challenging surgical procedure of knot tying following dural suturing in TSS. Its potential future applications may extend to include other neurosurgical procedures in anatomically restricted areas.