From: Rabbi Moshe Sofer
To: Rabbi Leib Litsch
A Sefer Torah was found with the majority of stitches between sheets torn, and a student-rabbi had ruled it invalid following the Taz. The Chasam Sofer upholds this ruling, determining that if neither the majority of the sheet's stitching nor the majority of the minimum stitches required to qualify the scroll as a 'sefer' remain intact, the Torah is not validated. He relies primarily on the Terumas HaDeshen and distinguishes between items naturally connected and those artificially joined by sewing, rejecting leniency arguments based on the latter analogy.
Source: Shu"t Chasam Sofer YD §275