Trepanation or trephination, commonly known as burr holes, is the act of intentionally perforating the skull for the purpose of healing or diagnosis.

Indications

Emergency indications

• evacuation of extradural or subdural haematoma

• insertion of intracranial pressure monitor

• insertion of external ventricular drain

Elective indications

• biopsy

• insertion of ventriculoperitoneal shunt

• insertion of deep brain stimulator electrodes

Contraindications

As burr hole surgeries are often performed in emergent settings, the only major contraindication is coagulopathy or use of anticoagulants by patients.

Technique

• the patient is placed supine on the table, head fixed and turned away from site of operation

• incision is identified. If the indication is to access the lateral ventricles, the Kocher's point is used

• hair is shaved around the planned incision

• the skin is infiltrated with local anaesthetics

• all layers of the scalp are cut, devided, and retracted

• the periosteum is lifted

• both tables of the skull are drilled using either a manual hand drill or electric drill, completing the burr hole

Complications

Apart from general anaesthetic complications, major complications of the burr hole procedure include infection (including abscess formation), post-operative haematoma needing further evacuation, paralysis, and death.

History and etymology

Early use of trepanation

The earliest evidence of trepanation dates back to the Neolithic period and is regarded as the first surgical procedure performed by man ⁴. 5-10% of all skulls discovered from the period around the world (including the Indo-Europe and South America) have been trephined ¹.

The purpose of prehistoric trepanation was thought to help release the unwanted spirits of vapours from the head. It is not as fatal as expected, as 80% of the subjects may have survived the procedure itself ². Some of the earliest research done on trepanation from the prehistorical era was performed by Professor Paul Broca (of Broca’s Area) at the University of Paris ³.

It is continued to be practised throughout history, from the Egyptian and Babylonian periods to the Mediaeval era. Egyptian and Babylonian cultures practice trepanation infrequently, and its use remained to be associated with magical and religious practices. Ancient Greco-Romanic culture saw the first medical use of trepanation, in which Galen described its use in managing pain in head injuries, and both religious and medical uses of trepanation were seen in the Middle Ages ¹.

Discontinuation

From the Renaissance period to the Early-Modern period, trepanation was more formally described in medical literature for the treatment of depressed skull fractures or penetrating head trauma. However, due to the high mortality, especially in the pre-penicillin era, it is criticised by many prominent surgeons in that period ³.

Burr hole surgery

It is only after the discovery of modern microbiology and aseptic surgery that allowed modern routine surgical trepanation, or burr holes, as it is now known.

Etymology

The terms trepan and trephine are often synonymous, but originates from different origins. Trepan came from the Greek word trupan “to bore”; whereas trephine came from Latin tres fines "three ends", a triangular instrument for trepanation first used by anatomist and Father of Embryology Hieronymus Fabricius ³.