Comparison of pull out strength of resorbable screws in human cadaveric laryngeal cartilage using different drill diameters

In a previous study at our institution, it was determined that resorbable screws with untapped drill holes resulted in the highest resistance forces to linear load when compared with titanium screws. The 1.1-mm drill diameter/2.0-mm screw diameter and 1.5/2.0 drill/screw combinations were superior to the 1.1/1.5 combinations; however, there was no conclusion as to the best screw size to drill bit diameter. The aim of this prospective study was to compare the pull out strength of resorbable screws in fresh frozen cadaveric laryngeal cartilage. The importance of drill hole diameter will also be determined. After debridement of connective tissue and perichondrium, 12 cartilage specimens were tested. Linear pull out strength of screws was measured using a load cell. Resorbable screws of size 2.0 mm were tested using drill hole diameters of 0.0 mm, 0.8 mm, and 1.5 mm. All tested screws were 6 mm in length or greater. We found no strong evidence that the means for the 0.8/2.0 and 1.5/2.0 differ or that the 0.0/2.0 and 0.8/2.0 means differ. There is evidence that the 0.0/2.0 and 1.5/2.0 means differ (adjusted p value .0108), with the 0.0/2.0 combination having a smaller mean. Resorbable screws without pre drilled holes result in less resistance to linear loads than either the resorbable screws with the 0.8/2.0 or the 1.5/2.0 drill/screw combinations. The 1.5/2.0 drill/screw combination had the strongest pull out force, though this was not statistically significant.