Efficacy of a new instrument for dural defect repair in anterior skull base reconstruction: a technical note

Specialised Surgical Instruments for Endoscopic and Endoscope-Assisted Neurosurgery: A Systematic Review of Safety, Efficacy and Usability

While there have been great strides in endoscopic and endoscope-assisted neurosurgical approaches, particularly in the treatment of deep-sited brain and skull base tumours, the greatest technical barrier to their adoption has been the availability of suitable surgical instruments. This systematic review seeks to identify specialised instruments for these approaches and evaluate their safety, efficacy and usability. Conducted in accordance with the PRISMA guidelines, Medline, Embase, CENTRAL, SCOPUS and Web of Science were searched. Original research studies that reported the use of specialised mechanical instruments that manipulate tissue in human patients, cadavers or surgical models were included. The results identified 50 specialised instruments over 62 studies. Objective measures of safety were reported in 32 out of 62 studies, and 20 reported objective measures of efficacy. Instruments were broadly safe and effective with one instrument malfunction noted. Measures of usability were reported in 15 studies, with seven reporting on ergonomics and eight on the instruments learning curve. Instruments with reports on usability were generally considered to be ergonomic, though learning curve was often considered a disadvantage. Comparisons to standard instruments were made in eight studies and were generally favourable. While there are many specialised instruments for endoscopic and endoscope-assisted neurosurgery available, the evidence for their safety, efficacy and usability is limited with non-standardised reporting and few comparative studies to standard instruments. Future innovation should be tailored to unmet clinical needs, and evaluation guided by structured development processes.

Failure Pressures of Dural Repairs in a Porcine Ex Vivo Model: Novel Use of Titanium Clips Versus Tissue Glue

Objective

Endoscopic skull base surgery is advancing, and it is important to have reliable methods to repair the resulting defect. The objective of this study was to determine the failure pressures of 2 commonly used methods to repair large dural defects: collagen matrix underlay with fibrin glue and collagen matrix underlay with polyethylene glue, as well as a novel repair method: fascia lata with nonpenetrating titanium vascular clips.

Methods

The failure pressure of the 3 dural repairs was determined in a closed testing apparatus. Defects in porcine dura were created and collagen matrix grafts were used as an underlay followed by either fibrin glue (FG/CMG) or polyethylene glycol glue (PEG/CMG). A third condition using a segment of fascia lata was positioned flush with the edges of the dural defect and secured with titanium clips (TC/FL). Saline was infused to simulate increasing intracranial pressure (ICP) applied to the undersurface of the grafts until the repairs failed.

Results

The mean failure pressure of the PEG/CMG repair was 34.506 ± 14.822 cm H₂O, FG/CMG was 12.413 ± 5.114 cm H₂O, and TC/FL was 8.330 ± 3.483 cm H₂O. There were statistically significant differences in mean failure pressures among the 3 repair methods.

Conclusion

In this ex vivo model comparing skull base repairs’ ability to withstand cerebrospinal fluid leak, the repairs that utilized PEG/CMG tolerated the greatest amount of pressure and was the only repair that exceeded normal physiologic ICP’s. Repair methods utilizing glues generally tolerated higher pressures compared to the novel repair using clips alone.

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.