The conception of minimally invasi...

The conception of minimally invasive neurosurgery, one time considered to be a contradiction in terminology, now has become an established discipline in succession the basis of a series of technical advances in optics and miniaturization. In late years, endoscopic techniques have been applied prosperously to the field of neurosurgery and have begun to revolutionize the management of a variety of neurosurgical disorders.(1)

Endoscopic neurosurgery is appealing for a number of reasons. Small endoscopes can be used to gain access to profound intracranial structures through tiny outlooks The surgeon is able to work subject to direct vision with minimal trauma to neural tissue. oftentimes this results in a quicker regaining and shorter hospitalization for the patient. Endoscopic techniques are not applicable to all neurosurgical manner of proceedings but for certain conditions, neuroendoscopic surgery is superior to conventional approaches and has become the performance of choice. This article reviews the history and evolution of endoscopic neurosurgery and describes the circulating applications of intracranial neuroendoscopy.

HISTORY

Endoscopic neurosurgery began in the early part of this hundred as an effort to diagnose and treat hydrocephalus. Ventricular shunting had not further been developed, and hydrocephalus was a disorder that inevitably be the effected in profound neurologic dysfunction or death. The technique of neuroendoscopic surgery was disentangleed when surgeons realized that the same instrument used to inspect the urinary bladder could be inserted into fluid-filled cerebral ventricles. In fact, the first neuroendoscopic measure was performed in 1910 by means of Victor Darwin Lespinasse, who was a urologist, not a neurologist. At the Wesley Memorial Hospital in Chicago, Lespinasse used a small rigid cystoscope to fulgurate the choroid plexus in sum of two units infants with hydrocephalus; one of the infants died immediately and the other died five years later. Lespinasse neared his findings to a local medical society if it were not that never published them.(2) Ultimately, he abandoned neuroendoscopy, which he considered "an intern's stunt" for other scientific interests, the mostly unusual of which was testicular transplantation for rejuvenation.

Walter Dandy, the pioneer neurosurgeon from John Hopkins and single of the founders of American neurosurgery generally is considered the father of neuroendoscopy, equable though his work in the field began many years after that of Lespinasse (Figure 1) In 1922 Dandy described using a small cystoscope to treat hydrocephalus by dint of coagulating the choroid plexus, long like the technique already described at Lespinasse. He described this technique in a one-paragraph article in the John Hopkins Hospital Bulletin and coined the denomination ventriculoscope in the same article.(3)

[Figure 1 ILLUSTRATION OMITTED]

The following year, W Jason Mixter, chief of neurosurgery at the Massachusetts General Hospital, reported the first prosperous endoscopic third ventriculoscopy. This was a modern technique he developed to treat hydrocephalus subject to endoscopic guidance by bypassing an obstruction in the ventricular system(4) To completely appreciate Mixter's ingenuity, one must first briefly review the pathophysiology of hydrocephalus.

Hydrocephalus, in general bourns is a condition in which there is an excessive amount of cerebrospinal fluid (CSF) that accumulates within the cerebral ventricles.(5) The human brain makes approximately 500 mL of CSF by day, most of which is generated through the choroid plexus within the ventricular regularity circulates around the brain and spinal cord, and ultimately is reabsorbed in the venous hypothesis Some patients develop an obstruction to the circulation of cerebrospinal fluid, which is known as aqueductal stenosis. This is a narrowing of single in kind of the ventricular chambers, called the aqueduct of Sylvius, that link togethers the third ventricle with the fourth ventricle. Aqueductal stenosis can be either congenital or acquire and it causes a backup of CSF that is generated proximal to the mould leading to enlargement of the lateral and third ventricles. The condition is a form of noncommunicating hydrocephalus because the blockage obstructs the CSF made in the lateral and third ventricles from circulating normally, and this fluid no longer communicates with the subarachnoid space.

Mixter reasoned that if he could come into the ventricular system with a small endoscope, he might be able to push a hole in the floor of the third ventricle and sidetrack the CSF into the subarachnoid space, where it could then circulate normally, having bypassed the obstruction at the aqueduct of Sylvius further downstream. Mixter used a primitive urethroscope and practiced the technique in succession a cadaver brain. He then performed the technique forward an infant with advanced noncommunicating hydrocephalus, using a flexible hale to make a hole in the floor of the third ventricle. Although this was before comput tomography or magnetic resonance imaging scans were available, Mixter was able to evince that his surgery was auspicious Preoperatively he instilled indigocarmine stain into the lateral ventricles yet was unable to recover it from a spinal needle placed in the lumbar subarachnoid space. Postoperatively, however, Mixter was able to heal the indigocarmine dye immediately from the lumbar spinal needle and the patient's head circumference became smaller and the fontanelle became smooth He published his work that year in the Boston Medical and Surgical Journal.(6)