Curiosity
2018; Lippincott Williams & Wilkins; Volume: 65; Issue: CN_suppl_1 Linguagem: Inglês
10.1093/neuros/nyy292
ISSN1524-4040
Autores Tópico(s)Psychological and Educational Research Studies
ResumoThis is a selfie taken by the Curiosity Rover on the surface of the planet Mars (Figure 1). The rover landed in the Mars Gale Crater Aug 5, 2012, less than 1.5 miles from its touchdown target after a journey of more than 350 million miles over 8.5 mo. Remarkably, within weeks, Curiosity rolled through an ancient streambed where water once flowed. It is still roving on Mars 5 yr later.FIGURE 1: Curiosity Rover on Mars. Photo by NASA, public domain.The Curiosity I’d like to talk about today has to do with the burgeoning field of Minimally Invasive Neurosurgery (Figure 2). I’d like to share with you some of the lessons I’ve learned working in that arena over the past 30 yr.FIGURE 2: Endoscopic resection of colloid cyst.Albert Szent–Györgyi was a biochemist who won the Nobel Prize for Physiology or Medicine in 1937 (Figure 3). He said something profound that applies to everyone in the audience: “Discovery consists of seeing what everybody has seen, and thinking what nobody has thought.”FIGURE 3: Albert Szent–Györgyi. CC BY-3.0, from FOTO: FORTEPAN/Semmelweis Egyetem Levéltára.The field of endoscopy dates back to at least the fourth century BC, when Hippocrates used a bamboo speculum to inspect the rectum and remove condylomata. But the godfather of endoscopy is Philipp Bozzini, of Mainz, Germany. In 1806 Bozzini developed the “Lichtleiter”, or Light Carrier, an aluminum endoscope consisting of a wax candle in a cradle, a set of reflective mirrors and a series of tubes that could be fitted at the other end to examine body cavities, which he did on cadavers. However, due to rampant internecine rivalry in 19th century Europe, when he presented his device to the faculty of the University of Vienna, he was roundly ridiculed and criticized for his “inappropriate curiosity” and his “magic lantern” was rejected. Bozzini died 3 yr later at the age of 36, and the field of endoscopy was set back for 50 yr (Figure 4).FIGURE 4: A, Philpp Bozzini. Portrait of Philipp Bozzini, 1773-1809. http://history.uroweb.org/biographies/bozzini-philipp/. Used with permission from the European Association of Urology and its European Museum of Urology. B, Bozzini's Lichtleiter. Image courtesy of the Archives of the American College of Surgeons. https://www.facs.org/about-acs/archives/pasthighlights/bozzinihighlight.Arthur Schopenhauer, the 19th century philosopher said, “All truth passes through 3 stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.” Schopenhauer's words certainly apply to the work of Bozzini, and many other investigators who have come after him. Another landmark advance in endoscopy came from Adolph Kussmaul of Freiburg, Germany in 1868 when he became the first to perform gastroscopy to examine the esophagus and fundus of the stomach, using a rigid tube with mirrors and a gasoline-powered lamp. The challenge was that most people cannot voluntarily release the cricopharyngeal muscle, so Kussmaul did the first procedure in a sword swallower. He actually brought sword swallowers with him on tour to demonstrate his new technique, and as a result he was honored by induction into the Sword Swallowers Hall of Fame (Figure 5).FIGURE 5: Sword swallower. From Hopkins, Albert (1897) Magic; stage illusions and scientific diversions, including trick photography, London: Sampson Low, Marston and Company, p. 158. Public Domain.Endoscopy has made advances in virtually every medical and surgical subspecialty, in man or beast, in which there is an air or fluid-filled cavity. It is surprising, then, that the field of neuroendoscopy began relatively late, as the cerebral ventricles are deep-seated, difficult to access, and filled with clear fluid. Neuroendoscopy began as an effort to diagnose and treat hydrocephalus, a once and sometimes still fatal disease. The first neuroendoscopic procedure was performed in 1910 by Victor Lespinasse, a Urologist from Chicago. He used a cystoscope to fulgurate the choroid plexus in 2 infants with hydrocephalus. One child died on the operating room table, the other lived for 5 yr and the work was never published, it appeared only as a footnote in a textbook, Neurological Surgery, by Loyal Davis, in 1936, who incidentally was Nancy Reagan's stepfather. Lespinasse was talented, but eccentric (Figure 6). He called the procedure “an intern's stunt” and abandoned the field. In 1922, he performed a famous operation on Harold Fowler McCormick, who was 50 yr old, and VP of International Harvester. He was the son of Cyrus McCormick, The Reaper King, and was married to Edith Rockefeller, daughter of John D. Rockefeller, the President of Standard Oil. On the right, the Chicago Tribune shows McCormick both before and after the secret operation.FIGURE 6: Victor Darwin Lespinasse. Reprinted from World Neurosurgery, 79(2), Decq P, Schroeder HWS, Fritsch M, Cappabianca P, A History of Ventricular Neuroendoscopy, S14.e1-S14.e6, 2013, with permission from Elsevier.McCormick was divorcing his wife and running off to Europe with the Polish opera singer, Ganna Walska (Figure 7). Impressed by the virility of his elderly father in law, McCormick submitted to an operation of testicular transplantation by Lespinasse (this was well before the era of Viagra). The secret operation was performed for an exorbitant fee of $50 000. The reason for such a fee is that it was said that the donor was a local blacksmith, who was amply remunerated for his donation. The Chicago Tribune and New York Times were replete with articles about denials and lawsuits. The local society clubs in Chicago shared the verse, adapted from Longfellow: “Under the spreading chestnut tree, the village smithy stands; The smith a gloomy man is he, McCormick has his glands.”FIGURE 7: Ganna Walska. PD-US, no known restrictions on publication.The same year, 1922, Walter Dandy of Johns Hopkins, used a Kelley cystoscope to inspect the lateral ventricles and avulse the choroid plexus in 2 infants with hydrocephalus, describing the outcome as only partially successful. He coined the term, “ventriculoscope.” The following year, in 1923, W. Jason Mixter, working at the MGH, performed the first successful endoscopic third ventriculostomy (ETV), fenestrating the floor of the third ventricle in a 9-mo-old infant with aqueductal stenosis (Figure 8). He published his operation in the Boston Medical and Surgical Journal, the forerunner of the New England Journal of Medicine.FIGURE 8: William Jason Mixter. Image printed with permission of Massachusetts General Hospital, Archives and Special Collections.ETV became the standard treatment for hydrocephalus, but the early instruments were poor and the morbidity and mortality rates were high, and ETV gradually fell out of favor, particularly in 1951 when Frank Nulsen and Eugene Spitz introduced ventricular shunting. Then the instruments got better and ETV was re-introduced by Gerard Guiot of Paris in 1962. Guiot placed an endoscope into one lateral ventricle and a spatula in the other to fenestrate the third ventricular floor in cases of aqueductal stenosis. In 1973 Takanori Fukushima, working in Tokyo, used a “ventriculofiberscope” to biopsy tumors of the lateral and third ventricles. In 1975, Huw Griffith of Bristol, England, used a rigid ventriculoscope with a solid rod lens system to treat hydrocephalus in children (Figure 9).FIGURE 9: Huw Griffith. From Maurice-Williams RS, Cummins B. Huw Griffith 1930–1993, British Journal of Neurosurgery, 7(6), 1993, reprinted with permission of Taylor & Francis Ltd, http://www.tandfonline.com.I became interested in the field about 30 yr ago, and began collaborating with the brilliant surgeon, Axel Perneckszky, of Mainz, Germany. Perneckzky coined the term keyhole surgery, and I searched far and wide for a picture of an old-fashioned keyhole, and finally found this one at a meeting in Wiesbaden, Germany. As luck would have it, the keyhole was on the door to the Men's Room, and someone opened the door and came out as I was snapping the photo. And I can tell you, that if something like that ever happens to you, don’t even bother trying to explain what you’re doing—there's nothing you can say that will make it better. We have rigid endoscopes with solid rod lens technology. And we have flexible endoscopes, that can be steered to look around corners. I tend to use the rigid lens system more often because I prefer the superior optics. I call the procedure, Nintendo Neurosurgery, because the image is projected through a camera onto a TV monitor. We learned early on to place the TV in front of the surgical team so we would not have to strain our necks. I began using ventriculoscopy to fenestrate loculated cysts in cases of complex hydrocephalus and to fenestrate the septum pellucidum for trapped lateral ventricles (Figure 10). Carl Heilman and I used a “saline torch”, a poor man's laser, developed by Kim Manwaring, to perform the fenestrations. Middle fossa arachnoid cysts lend themselves nicely to endoscopic fenestration, because they are large and filled with clear fluid (Figure 11). The cysts can be fenestrated to the basal cisterns. However, I prefer to do these fenestrations using a mini craniotomy because it enables me to have better control and make larger fenestrations.FIGURE 10: A, Endoscopic fenestration of septum pellucidum. B, Closer view.FIGURE 11: Left middle fossa arachnoid cyst.Suprasellar arachnoid cysts, which can obstruct the foramina of Monro and cause symptomatic hydrocephalus, are ideally suited for endoscopic fenestration (Figure 12). Through a single burr hole, one can perform a ventriculocystostomy, fenestrating the cyst into the ventricle, as well as a cystocisternostomy, fenestrating the cyst into the basal cisterns, obliterating the slit valve mechanism that may be responsible for enlargement of these cysts.FIGURE 12: Large suprasellar arachnoid cyst.I became interested in endoscopic third ventriculostomy as a rejuvenation of Mixter's operation from 1923, now that the instruments are better. The procedure is ideally suited for acquired noncommunicating hydrocephalus, for example, aqueductal stenosis, as fenestration of the thinned tuber cinereum at the third ventricular floor permits the operator to short circuit CSF into the basal cisterns, bypassing the obstruction downstream (Figure 13).FIGURE 13: Endoscopic third ventriculostomy.ETV entails poking a hole in the third ventricular floor and dilating it with a balloon catheter. Once the fenestration is created one has a clear view of the basilar artery in the interpeduncular cistern. The fenestration is made under direct endoscopic visualization anterior to the mammillary bodies, away from the underlying basilar artery. When I started doing ETV, there was a move to use tiny diameter fiberscopes, in the hope of minimizing trauma to the brain. The problem, though, was that the optics were so poor it was difficult to do anything therapeutic. So I started using higher resolution rod lenses through a sheath with working channels and the anatomy immediately became clearer. Figure 14 showsa view of the right foramen of Monro. One can clearly identify the periforaminal structures and third ventricular floor. A balloon catheter is passed through the third ventricular floor. The balloon is inflated to create the fenestration. And that's the entire procedure (Figure 14).FIGURE 14: A, Right foramen of Monro. B, Fogarty balloon catheter. C, Enlarging the fenestration. D, Fenestration in third ventricular floors.We published a series of 100 consecutive cases of ETV with an overall success rate of 75%, with no deaths. The single most powerful prognostic factor was inferior bowing of the third ventricular floor. If the floor was bowed down on the preop MRI, the overall success rate was 79%. ETV is effective in treating hydrocephalus associated with pineal tumors, permitting CSF sampling and tumor biopsy in the same sitting. The approach to the anterior third ventricular floor through the foramen of Monro for ETV is usually just in front of the coronal suture, while the approach to the posteriorly situated pineal tumor is fairly more anterior. We developed a “split the difference” technique that permits both procedures to be performed through a single burr hole. For tumors that will require open microsurgical resection, this can be carried out electively with the hydrocephalus controlled. Neuroendoscopy is not difficult, but it is different, and the success of procedures is often dependent on attention to subtleties or nuances of judgment and technique. For ETV, it is essential to plan the trajectory, and the sagittal MRI is helpful for choosing the site of the burr hole. As Yogi Berra said, “Baseball is 90% mental, the other half is physical.” The same holds true for neuroendoscopy—most of the effort is in the planning. Because ETV is a midline operation, it is helpful to move the burr hole more medial than the standard mid-pupillary line. When necessary, image guidance can be useful for planning the trajectory (Figure 15).FIGURE 15: A, Frameless stereotactic navigation. B, Frameless stereotactic navigation.The anatomy is fairly constant, but one only sees a small amount of it at any given time, and it can be easy to get lost. It is prudent to practice the procedure before performing it live (Figure 16). We have worked to develop novel teaching techniques, collaborating with computer scientists to create a virtual reality simulator. The virtual reality simulators combine visual images rendered from MR scans with haptic (tactile) feedback.FIGURE 16: Minimally invasive neurosurgery laboratory.Recently, when I was at Boston Children's Hospital, I worked with a group of simulation engineers, neuroradiologists, and special effects technologists from Hollywood, Fractured FX, using 3-dimensional printing to create ultrarealistic physical models rendered from MR images so that trainees can practice minimally invasive techniques in a pulsating brain in which CSF is flowing and blood vessels are beating (Figure 17).FIGURE 17: 3D model of endoscopic third ventriculostomy. Cover of Journal of Neurosurgery: Pediatrics, July 2017, reprinted with permission of JNSPG.As technology has improved, indications for neuroendsocopy have increased. Colloid cysts of the third ventricle can obstruct the foramina of Monro causing symptomatic hydrocephalus. Conventional treatment entails craniotomy and microsurgical resection. This avascular tumor sitting in a lake of CSF lends itself nicely to an endoscopic approach. We began using an endoscopic approach to resect colloid cysts in the early 1990s, employing a YAG laser to open the capsule and microinstruments to resect the cyst. The success of surgery depends upon having adequate visualization of the mass in the foramen of Monro. Unlike ETV, where we move the burr hole more medially, for colloid cysts we move the burr hole more anteriorly and laterally. Here, the operator has a nice face-on view of the lesion obstructing the foramen. Endoscopic resection can be highly effective in selected patients (Figure 18).FIGURE 18: Endoscopic resection of colloid cyst. Reprinted from Neurosurgical Operative Atlas, 1993, Alan R. Cohen, with permission of the American Association of Neurological SurgeonsAnother novel approach to these cysts is neuroendoport surgery. A slightly larger tube permits the surgeon to use better instruments and bimanual technique. Here's a large colloid cyst that we removed using a neuroendoport technique. Here's the resection performed using an endoport. The hypothalamic hamartoma can cause gelastic seizures that can be medically intractable. This 9-yr-old boy had been misdiagnosed for years because the small lesion was not recognized. The endoscopic approach can be tricky because of the small size of the ventricles, so frameless navigation is helpful. The endoscope is guided through the foramen of Monro and the subependymal hamartoma is resected. Removing that small lesion had a dramatic effect on that youngster because it eliminated his seizures. The endoscope can be used in conjunction with the microscope to perform synchronous surgery for selected cases (Figure 19). For example, some large cystic and solid adamantinomatous suprasellar craniopharyngiomas in children cause hydrocephalus and are also adherent to neurovascular structures at the skull base. The ventriculoscope can empty the cystic component from above to make the microsurgical resection from below easier. We and others have used this technique of burr hole ventriculoscopy in combination with skull base microsurgery to facilitate resection of some of the tougher tumors.FIGURE 19: Synchronous microsurgery and endoscopy. Reprinted with permission. Copyright © 2010, © 2010 S. Karger AG, BaselIn the lab, we have developed some minimally invasive epilepsy procedures, including endoscopic hemispherotomy for medically intractable epilepsy. The procedure, anatomic hemispherectomy, is one of the most invasive operations ever developed. Over time the operation has been modified to a less invasive hemispherotomy. We went a step further and developed a technique of endoscopic transventricular hemispherotomy, and in a cadaveric model, we were able to disconnect the entire hemisphere using only 2 burr holes (Figure 20).FIGURE 20: Endoscopic hemispherotomy. Cover of Journal of Neurosurgery: Pediatrics, December 2010, reprinted with permission of JNSPG.Endoscopic endonasal surgery is effective n approaching parasellar lesions. Here is a transnasal removal of a craniopharyngioma under endoscopic guidance (Figure 21).FIGURE 21: A, Craniopharyngioma, Preop MRI. B, Postop MRI.Endoscope-assisted microsurgery enables the operator to expand the field of vision and look around blind corners. The endoscope can be a useful adjunct to the microscope for tumors at the skull base, such as intracranial epidermoids, which can weave around basal cisterns and have hidden components. In one case, we used the endoscope to facilitate total resection of an epidermoid tumor within the substance of the brainstem at the pontomedullary junction. The endoscope can be used in conjunction with the microscope to help identify hidden remnants of vestibular schwannomas and clival chordomas. In vascular neurosurgery, the endoscope can sometimes be helpful for inspecting the position of an aneurysm clip to ensure there are no perforators being occluded. For endoscope-assisted microsurgery to be useful, your operating room needs to be familiar with setting up the equipment. Otherwise, it is too laborious and time-consuming to be of practical value. Endoscopic neurosurgery is a burgeoning field that is still evolving. The 18th century German philosopher, Johann Wolfgang von Goethe, said, “Man sieht nur was man Weiss.” “One sees only what one knows.” In this tour of the evolution of neuroendoscopy, we one can appreciate that advances in the field came when investigators looked farther than they were able to see. Disclosure The author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.
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