Development of a Semiautomatic Dura Mater Suturing Device for Preventing Cerebrospinal Fluid Leakage in Transsphenoidal Surgery

Need

In transcranial surgery, watertight direct dural suturing is widely performed to prevent cerebrospinal fluid leak because it is the simplest and most practical and reliable method.^1-5 However, a considerable amount of operating time is spent on suturing the dura when performing transsphenoidal surgery (TSS). According to Nishioka et al, ⁵ dural suturing increases the operating time by 30 minutes. Therefore, there is a need for surgical instruments that allow easier, secure, and more rapid dural suturing. We have developed a semiautomatic suturing device with a novel mechanism that can be used to stitch the dura.

Technical Solution

The ideal dural suturing device must satisfy the following criteria: (1) the device should be able to pass the suture threads through the dura in 2 directions, that is, from the nasal cavity side to the pituitary side and vice versa; (2) the suture thread should be able to be passed through multiple portions of the dura without needing to be drawn outside of the body; and (3) the outside diameter of the nasal insertion component is 3 mm or less, which is the same as for the surgical tools generally used in TSS. Our prototype suturing device is shown in Figure 1A. The device measures 340 × 100 × 11 mm. The nasal insertion component has an outer diameter of 3 mm and a length of 230 mm.OPEN IN VIEWER

Figures 1B and 2 show a cross-sectional view of the main components of the tip and the suturing mechanism. When suturing in any direction, the objective is achieved by passing the thread through the dura with a needle on one side, and the thread catch on the other side grasps the suture. This design and mechanism meet the above 3 criteria.OPEN IN VIEWER

Proof of Concept

Two artificial dura mater preparations were placed on a goniometer stage with a gap of 5 mm. A silicon tube (outer diameter, 13 mm; length, 100 mm) was fixed vertically on the artificial dura mater. As shown in Figure 3A, the suture thread was passed through 2 points of the dura to connect the edges of the artificial dura mater. All sutures were carried out while observing the endoscopic image (Figure 3B).OPEN IN VIEWER

An engineer (subject 1) who was not a medical practitioner but was skilled in the use of the suturing device manipulated the developed suture device while a surgeon with more than 10 years of experience performing TSS on a daily basis (subject 2) and a young surgeon who had never previously sutured the dura during TSS (subject 3) used a conventional needle holder. The 3 subjects each performed 5 suturing trials. The suturing time and numbers of device reinsertions and needle drops were compared between the 3 subjects.

Results

Figure 3C shows the suturing procedure when using the prototype device. The mean suturing time (with standard deviation) was 49.8 ± 3.6 seconds in subject 1, 86.2 ± 39.8 seconds in subject 2, and 267.0 ± 145.0 seconds in subject 3. There was a significant difference in suturing time between subjects 1 and 2 (P = .037) and between subjects 1 and 3 (P = .027). The results tended to be less variable when suturing with the novel device than when suturing with the needle holder.

The device was taken out of the tube 1.0 ± 1.3 times by subject 2 and 24.6 ± 4.2 times by subject 3. The needle was dropped into the tube .0 ± .0 times by subject 2 and 24.6 ± 4.2 times by subject 3. Use of the novel suture device (by subject 1) did not require the needle to be changed and there was no risk of dropping the needle. The suturing time required by subjects 2 and 3 was longer because of the time required for device reinsertion and retrieving the dropped needle.

Next Steps

A comparative crossover study in which a larger number of operators perform suturing using this novel device and a conventional needle holder is needed in the future.

Conclusion

We have developed a semiautomatic suturing device to assist dural suturing in TSS. Surgeons with limited experience in performing TSS can use this device as effectively as experienced surgeons with little variation in suturing time.