Craniotomy

A craniotomy is a surgical procedure in which a part of the skull is temporarily removed to expose the brain and perform an intracranial procedure. The most common conditions that can be treated via this approach include brain tumors, aneurysms, arteriovenous malformations, subdural empyemas, subdural hematomas, and intracranial hematomas. Specialized tools and equipment are used to remove the section of bone, known as the bone flap. The bone flap is temporarily removed, placed on the surgical instrument table, and then reapplied back after the brain surgery has been concluded. In some cases, depending on the indication for the procedure, the bone can be discarded, stored in an abdominal subcutaneous space, or cryopreserved under cold storage conditions. If the bone flap is discarded or not replaced during the same operation, the procedure is called a craniectomy. In a decompressive craniectomy used for the treatment of malignant brain edema, the bone flap is placed back several weeks after the brain swelling has resolved (see . Decompressive Hemicraniectomy). The surgical procedure to reconstruct and replace the bone flap in the skull during a second intervention is known as a cranioplasty. From a historical perspective, cranial interventions have ranged from a single burr hole trephine to a much larger craniectomy. Modern craniotomies are performed by connecting a series of burr holes. Although trephination is the oldest known cranial surgical technique, with ancient reports dating back 2300 years, our modern surgical technique for a craniotomy is the result of a procedure introduced at the end of the 19th century by the self-educated surgeon Wilhelm Wagner. Although the transition from trephination to a tailored intracranial resection via craniotomy that occurred much later in history, ancient civilizations, eg, the Incas in Peru, likely had some basic familiarity with brain anatomy and surgical interventions, despite their rudimentary knowledge of pathology. Depending on the type of intracranial lesion, pathology that was present, and surgical approach, some craniotomy procedures can be aided by neuronavigation guidance based on magnetic resonance imaging (MRI) or computed tomographic (CT) scans to customize the procedure to the size of the mass lesion, using the smallest incision that is required. Neuronavigation is a modern, computerized technology that helps surgeons localize pathology more precisely by merging a series of craniofacial points present in the patient located in the surgical field. Neuronavigation offers improved surgical guidance, orientation, and localization that provides the surgeon with greater technical confidence and improved patient outcomes. The craniotomy approach has evolved, dating back to the Neolithic period. Trepanation, meaning “borer”, became synonymous with trephination because of the French instrument , meaning “3 ends”. Trephination has been performed by prehistoric peoples either for magic or religious rituals to release demons and malignant spirits, or to wear the skull bone as an amulet. During the Neolithic era, therapeutic drilling was performed by pointed or sharp cutting tools made up of silica or obsidian. The principle of bow drilling originated in fire-making and was used by the Egyptians around 1400 BC. A sharp rod made of hard stone or metal was swiveled rapidly between the hands and later by a cord and the string of a bow to make a circle of small holes where the bony bridges between them were connected. The approach to craniotomy is attributed to Imhotep, who is believed to have described it around 2900 BCE. Hippocrates first reported the therapeutic use of craniotomy for the management of fractures in the fifth century BC. The instruments were detailed as early as 1518 in “De fractura calvae” by Berengario. Broca also related the archaeological findings of trepanation of the skull. Celso advocated for trephination, a sequential process involving the external cortex, diploic space, and the internal cortex, while safeguarding the meninges. William Detmold first operated on a brain abscess within the lateral ventricle in 1850. Craniotomy evolved in the Renaissance, when firearms and grenades were used, in the 16th and 17th centuries. The use of angulated manual trephines, equipped with a series of perforating or cutting terminals, was introduced in the 16th century. In 1889, Wagner first performed an osteoplastic bone flap. The Gigli saw was used by Obalinski in 1897. At the beginning of the 19th century, the use of craniotomy declined primarily due to the development of infections, and trephining was limited to exceptional cases. Advancements in antisepsis and general anesthesia in the 19th century led to an exponential growth in the use of trephination and craniotomy, even for nontraumatic intracranial lesions.