Most laminectomy punches have jaw openings in the range of ten to twelve millimeters: a good and reasonable opening for a punch. Over the years, so many surgeons have asked for rongeurs with wider jaw openings we decided to modify those with the large handles to open to 16 mm. Jaw opening is determined by the distance the upper shaft travels along the track of the lower shaft. This "travel" is a function of the primary pivot point around which the handles rotate and the secondary pivot point connecting the forward, articulating handle to the upper shaft. The longer the distance between these points, the longer the arc over which the secondary pivot (and upper shaft to which it is attached) will travel.

Increasing the arc of rotation of the forward handle can also increase the distance the upper shaft travels but this requires the handles to spread even further apart when operating. As the grip requirements of a large handle punches are already at the physiological limits of the grasp of most spine surgeons this option is decidedly less attractive. At the design limits, instrument crafting becomes as much an art as a science. After "tweaking" the many subtle variables as well as the more obvious options discussed above, we have managed to increase the opening of our large handle punches to sixteen millimeters. Some slight variances may be noted, depending on size and style of bite, but these instruments are routinely supplied with the large opening feature in 180 mm, 200 mm, 230 mm, 250 mm and 300 mm shaft lengths. The extraordinary pressure that can be imparted on the footplate by large handle rongeurs demands prudence, so Buxton offers these punches only in bite sizes of two through six millimeters wide and with a standard footplate pattern.

Talking Back, Vol. 3, No. 2