Suction cannula design for safe microneurosurgery

Suction cannula (SC) is an important instrument for a neurosurgeon. Currently used suction control valves, kept in the sterile field, are controlled by the surgeon, for which he needs to leave the surgical dissection or by assistant or by operation room personnel to adjust the pressure of the equipment (suction machine or central suction), which lies in the unsterile field. Authors studied relationships of the different diameters of SC and the thumb hole (TH) of the SC and present their findings.

Seven SC with various diameters of their lumen and TH were used for the study. Suction pressures were measured with suction tip open, immersed in saline and TH open and closed. TH of 2 SC were made smaller using adhesive tape over the TH and making smaller hole over the tape and two additional measurements were taken using changed SC with modified TH. SPSS Statistics 23.0 (IBM India Pvt Ltd, Bangaluru, India) was used for statistical analysis of the pressure recordings and SC features.

Pressure and diameter of ST or TH were related in opposite direction. As the diameter increases the pressure decreases. A strong negative association was observed between the diameter of TH and the pressure.

TH diameter of SC is important to control suction pressure with any size of SC. One should use tear-drop type TH or appropriate diameter of the circular type of TH to contemplate safe microneurosurgery.