Trepanning

Trephine, Neurosurgery, Trepanation

Drawings from

Bourgery & Jacob

Trepanning is the medical process of drilling or cutting a hole into the skull in order to relieve pressure on the brain tissue, lift a compression fracture of the skull, or remove a blood clot on the brain. If a person had a concussion with depression of the skull bone, that depressed area would need to be lifted or removed and then the clot under the concussion removed to alleviate trauma induced symptoms.

The process is documented to have been performed as far back as 4000 years ago by the Inca Indians of Peru. If you would like more information on this procedure and the history, please do a search for the words: trephine, Inca, neurosurgery, trepanning, trepan on Google.com.

Trepanning (pronounced: tree-panning), as was frequently practiced in America during the 1800's, was performed with an instrument called a trephine (pronounced: tray-feene or tree-fine) which actually is a saw that cuts a circular hole in the scull.

The scalp over the skull is first incised with a scalpel, a flap laid back, and the hole bored or saw cut by a twisting motion of the trephine. In some types of trephines, there is a center drill which holds and guides the outer cutting edge of the saw. There are two main types of trephine saws, the earlier crown type and the later Galt type.

Case study citations of trepanning performed during the Civil War from the Medical and Surgical History of the War of Revolution

Scalpel for tissue incision

Trephine with 'Galt' style saw (assembled) c. 1870

An all 'metal' trephine, post 1900

Another instrument used for this procedure is the Hey saw, which has both a straight and curved tooth edge for cutting into the skull.

Hey saw used to cut into the skull bone

The circular piece of bone, about the size of a nickel is then removed by using one end of a lenticular or bone rasp to lift out the bone, then the edges of the bone would be smoothed with the rasp.

Bone file for smoothing edges and lifting out parts of bone.

Any bone dust could then be removed with the bone brush before cutting into the dura, which is the outer covering of the brain.

Bone brush to remove bone sawdust from the cutting site.

Examples of American cased trepanning sets

Wiegand & Snowden, c. 1830

Pre-1860 removable handles, (center is turned wood),

(left is carved ebonized wood), (right is heat molded)

Pre-1860 Crown type cutting heads, typical of the 1830-50 era

Variations on Hey saw designs



Fig. 1: Cased Trepanning s       Fig. 2: Trepanning instruments

In figure 1, is a cased trepanning set by Wade and Ford. The set contains a lenticular bone rasp, scalpel, Hey saw, crown type trephine, wood handle for the trephine, and both a crown and a Galt type trephine (disassembled).



Fig. 3: Trephanning cased set   Fig. 4: instruments from case

The set in figure 3 contains a bone brush and is missing the scalpel. Figure 4 shows the individual instruments from the Gemrig set. The trephine is assembled with a crown type trephine saw.

These type of cased sets were issued to the Union surgeons during the Civil War and made by makers like Gemrig, Tiemann, and Hernstein. For additional information see trepanning during the Civil War. Display of multiple trepanning sets in all the multiple Displays on this site.

The set is engraved on the cartouche with " U S A" and the label indicates the last year Hernstein would have used this label, which is the first year of the War. The label also indicates the set was produced under contract for the U. S. Army Hosp. Dept.