History of neurology and neurosurgery

Trepanned Incan skulls

The Incas appear to have practiced trepanning since the late Stone Age,[1] a method that is compared to similar techniques used today.[2] These procedures were mostly performed on combatants, with evidence from skeletal remains revealing that the earliest methods usually resulted in death.[2] However, by the 1400s, Incas proved to be "skilled surgeons", as survival rates rose to about 90%, infection rates following the procedure were low and evidence was found showing that some individuals survived the surgery on multiple occasions.[2] Incan surgeons learned to avoid areas of the head that would cause injury, using a scraping method on the skull that would cause less trauma.[2] They also likely used medicinal herbs of the time, such as coca and alcohol for pain while balsam and saponin would be employed for antibiotic purposes.[2]

The Buddha's physician, Jīvaka Komārabhacca, performed surgery to remove two parasites from a patient's brain in the 5th century BCE.[3]

An ancient Egyptian treatise concerning trauma surgery, the Edwin Smith papyrus, contains descriptions and suggests treatments for various injuries, including some of neurological nature. Specifically, there are descriptions of the meninges, the external surface of the brain, the cerebrospinal fluid and the intracranial pulsations.[4] Not only are these neurological features mentioned, but it is also noticed that some bodily functions can be impaired by brain injuries or injuries to the cervical spine.[4] There are many other examples of observations of neurological phenomena throughout history. The Sumerians illustrated paraplegia caused by physical trauma in a bas relief of a lion with an arrow in its back.[5] Neurological disorders not caused by physical disorder were also investigated. For example, in the medicine of the Vedic period of ancient India, the Ayurvedic text Charaka Samhita discusses epilepsy, with a discussion of both symptoms and of possible treatments.

Galen demonstrating the recurrent laryngeal nerves in public

Slightly later, the ancient Greek physician Hippocrates was convinced that epilepsy has a natural cause, not a sacred one.[6] The ancient Greeks also dissected the nervous system. For example, Aristotle (although he misunderstood the function of the brain) describes the meninges and also distinguishes between the cerebrum and the cerebellum.[7] Slightly later, in Rome, Galen performed many dissections of the nervous system in a variety of species, including the ape. One particular discovery he made was of the importance of the recurrent laryngeal nerves. Originally, he cut through them accidentally while performing an experiment on the nerves that control breathing by vivisection of a strapped-down, squealing pig. The pig immediately stopped squealing, but continued struggling. Galen then performed the same experiment on a variety of animals, including dogs, goats, bears, lions, cows and monkeys, finding similar results each time. Finally, to publicise this new result, Galen demonstrated the experiment on a pair of pigs to a large audience in Rome, telling them: "there is a hairlike pair [of nerves] in the muscles of the larynx on both left and right, which if ligated or cut render the animal speechless without damaging either its life or functional activity".[8]

With surgery, Hua Tuo was an ancient Chinese physician and surgical pioneer who is said to have performed neurosurgical procedures.[9] In Al-Andalus from 936 to 1013 AD, Al-Zahrawi evaluated patients and performed surgical treatments of head injuries, skull fractures, spinal injuries, hydrocephalus, subdural effusions and headache.[10] Concurrently in Persia, Avicenna also presented detailed knowledge about skull fractures and their surgical treatments.[11]

There was not much advancement in neurosurgery until late 19th early 20th century, when electrodes were placed on the brain and superficial tumors were removed.

Neurosurgery, or the premeditated incision into the head for pain relief, has been around for thousands of years, but notable advancements in neurosurgery have only come within the last hundred years.[16]

History of electrodes in the brain: In 1878 Richard Caton discovered that electrical signals transmitted through an animal's brain. In 1950 Dr. Jose Delgado invented the first electrode that was implanted in an animal's brain, using it to make it run and change direction. In 1972 the cochlear implant, a neurological prosthetic that allowed deaf people to hear was marketed for commercial use. In 1998 researcher Philip Kennedy implanted the first brain–computer interface (BCI) into a human subject.[17]

History of tumor removal: In 1879 after locating it via neurological signs alone, Scottish surgeon William Macewen (1848-1924) performed the first successful brain tumor removal.[18] On 25 November 1884 after English physician Alexander Hughes Bennett (1848-1901) used Macewen's technique to locate it, English surgeon Rickman Godlee (1849-1925) performed the first primary brain tumor removal,[19][20] which differs from Macewen's operation in that Bennett operated on the exposed brain, whereas Macewen operated outside of the "brain proper" via trepanation.[21] Three years later, Victor Horsley (1857–1916) was the first physician to remove a spinal tumour. On 16 March 1907 Austrian surgeon Hermann Schloffer became the first to successfully remove a pituitary tumor.[22] American surgeon Harvey Cushing (1869–1939) successfully removed a pituitary adenoma from an acromegalic in 1909. Treating endocrine hyperfunction by neurosurgery was a major neurological landmark.

Egas Moniz (1874–1955) in Portugal developed a procedure of leucotomy (now mostly known as lobotomy) to treat severe psychiatric disorders. Though it is often said that the development of lobotomy was inspired by the case of Phineas Gage, a railroad worker who had an iron bar driven through his left frontal lobe in 1848, the evidence is against this.[23]

The main advancements in neurosurgery came about as a result of highly crafted tools. Modern neurosurgical tools, or instruments, include chisels, curettes, dissectors, distractors, elevators, forceps, hooks, impactors, probes, suction tubes, power tools, and robots.[24][25] Most of these modern tools, like chisels, elevators, forceps, hooks, impactors, and probes, have been in medical practice for a relatively long time. The main difference of these tools, pre and post advancement in neurosurgery, were the precision in which they were crafted. These tools are crafted with edges that are within a millimeter of desired accuracy.[26] Other tools such as hand held power saws and robots have only recently been commonly used inside of a neurological operating room.