CINCINNATI – Pisa con cuidado. Esa es una de las reglas más importantes para los neurocirujanos que operan en la parte inferior del cerebro, una región compleja y congestionada de vasos, nervios y estructuras óseas llamada base del cráneo. Es una región en la que importan los milímetros, donde un giro incorrecto o un empuje errante pueden producir complicaciones peligrosas.
Es un área del cerebro que continúa fascinando a Norberto Andaluz, MD, neurocirujano de la base del cráneo en Mayfield Brain & Spine. Es el investigador principal de tres publicaciones recientes, dos en la revista Neurocirugía Operativa y una en el Journal of Neurosurgery. Todos brindan nuevos conocimientos prácticos sobre el tratamiento de los tumores de la base del cráneo en la parte anterior (frontal) de la cabeza, cerca del ojo.
“Estamos buscando la forma menos agresiva de abordar un tumor”, dice el Dr. Andaluz. “Queremos los mejores resultados, las cirugías menos desfigurantes y las recuperaciones más rápidas para nuestros pacientes.
“Estos tumores son muy difíciles de tratar. Uno de los objetivos de la cirugía es evitar que el paciente quede ciego cuando el tumor está cerca del nervio óptico “.
En los estudios, el Dr. Andaluz y su equipo estudiaron el potencial de incorporar enfoques quirúrgicos tradicionales con enfoques endoscópicos más nuevos a través de la nariz y los párpados. En un estudio, el Dr. Andaluz y sus colegas investigadores compararon dos enfoques diferentes para la descompresión (apertura del espacio) del conducto óseo óptico, a través del cual pasa el nervio óptico. El nervio puede comprimirse o comprimirse a medida que crece un tumor.
“Históricamente, la descompresión se realizaba a través de un abordaje transcraneal, donde abríamos la cabeza del paciente y abríamos el techo sobre la órbita y el canal del nervio óptico”, dice el Dr. Andaluz. “El problema es que a veces el tumor bloquea la visión del nervio óptico por parte del cirujano, por lo que debe realizar un abordaje muy grande en un entorno más arriesgado. En estas situaciones, el nervio óptico puede ser inseparable del tumor, o con un riesgo muy significativo de daño debido a la manipulación excesiva y la pérdida de suministro de sangre “.
Si este acercamiento al canal óptico no puede realizarse de manera segura a través del callejón transcraneal, el Dr. Andaluz continúa: “Otra forma de tratar la compresión es pasar por la nariz”.
En un entorno de laboratorio, los cirujanos descomprimieron los conductos ópticos con un abordaje quirúrgico tradicional, que requería hacer una abertura en el cráneo, y un abordaje menos invasivo, que implicaba el avance de instrumentos largos y angostos por la nariz. Es importante destacar que no estudiaron si se podía hacer el abordaje, sino si se podía hacer sin causar daño al paciente.
“Uno de los riesgos de hacer esta descompresión a través de la nariz o el cráneo es que puede violar los sellos que contienen el líquido cefalorraquídeo”, dice el Dr. Andaluz. “Lo que hicimos fue estudiar específicamente cuánto podemos permitirnos descomprimir tanto la vía transcraneal como la endonasal sin causar complicaciones por la fuga de líquido cefalorraquídeo”.
El Dr. Andaluz y su equipo concluyeron que el enfoque tradicional proporcionaba a los neurocirujanos “una amplia visualización y una amplia exposición”, mientras que limitaba el riesgo de causar una fuga de líquido cefalorraquídeo. El enfoque endonasal, en comparación, ofreció una ventana de visibilidad más estrecha. “A pesar de que los enfoques endoscópicos endonasales han ganado popularidad, es posible que no siempre sean lo mejor para un paciente individual”, dice el Dr. Andaluz. “El valor real aquí es demostrar ambas técnicas y poder ofrecer la que pueda descomprimir el nervio óptico de manera más segura sin exponer al paciente a riesgos excesivos”.
En un segundo estudio, el Dr. Andaluz y sus colegas estudiaron las rutas orbitales utilizadas para alcanzar tumores raros de la cavidad orbital y su entorno dentro del cráneo. Buscaron una ruta óptima que podría reducir la cantidad de retracción cerebral y la extracción ósea normalmente requerida. Los cirujanos recurrieron a la experiencia de los oftalmólogos para comparar enfoques mínimamente invasivos en regiones profundas y complejas del cerebro central (fosa craneal media).
“Hemos visto técnicas en áreas donde no se puede obtener un buen alcance ni por la nariz ni por la cabeza”, dice el Dr. Andaluz. “Observamos diferentes formas y diferentes rutas”.
Aunque el estudio es “muy preliminar”, el Dr. Andaluz dice que le dio a los cirujanos ideas sobre cómo tratar los tumores raros en esta región difícil de alcanzar al acercarse a través de una pequeña incisión en el párpado superior.
En un tercer estudio, el Dr. Andaluz y su equipo combinaron las rutas establecidas para los tumores orbitales en un enfoque novedoso y mínimamente invasivo. Los cirujanos concluyeron que acercarse a los tumores a través de una incisión en forma de ojo de cerradura en el párpado permite una buena visualización de las estructuras en el cerebro medial, pero que se necesitan estudios futuros.
El Dr. Andaluz dice que quiere que su investigación anatómica tenga implicaciones prácticas y clínicas. “Quiero ver cuánto puedo hacer por mi paciente”.
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Through Study of Anatomy, Mayfield Neurosurgeon Seeks Safest Pathways to Tumors of the Skull Base
CINCINNATI — Tread carefully. That is one of the most important rules for neurosurgeons who operate in the lower part of the brain, a complex and congested region of vessels, nerves, and bony structures called the skull base. It is a region where millimeters matter, where a wrong turn or an errant poke can produce dangerous complications.It is an area of the brain that continues to fascinate Norberto Andaluz, MD,a skull base neurosurgeon with Mayfield Brain & Spine. He is the principal investigator of three recent publications, two in the journal Operative Neurosurgery and one in the Journal of Neurosurgery. All provide new practical insights into treating skull base tumors in the anterior (front) part of the head, near the eye.
“We are looking for the least aggressive way of approaching a tumor,” Dr. Andaluz says. “We want the best outcomes, the least disfiguring surgeries, and the quickest recoveries for our patients.
“These tumors are very difficult to treat. One of the goals of surgery is to save the patient from going blind
when the tumor is in proximity of the optic nerve.”
In the studies, Dr. Andaluz and his team studied the potential for incorporating traditional surgical approaches with newer endoscopic approaches through the nose and eyelid. In one study, Dr. Andaluz and his fellow researchers compared two different approaches to decompression (opening up space) of the bony optic canal, through which the optic nerve passes. The nerve can become compressed, or squeezed, as a tumor grows.
“Historically, decompression was done through a transcranial approach, where we open the patient’s head and open the roof above the orbit and the optic nerve canal,” Dr. Andaluz says. “The problem is that sometimes the tumor is blocking the surgeon’s view of the optic nerve, so you have to perform a very large approach in a riskier setting. In these situations, the optic nerve may be inseparable from the tumor, or at a very significant risk for damage due to excessive manipulation and loss of blood supply.”
If this approach to the optic canal cannot be done safely through the transcranial alley, Dr. Andaluz continues, “Another way to treat the compression is to go through the nose.”
In a laboratory setting, the surgeons decompressed optic canals with a traditional surgical approach, which required making an opening in the skull, and a less invasive approach, which involved advancing long, narrow instruments through the nose. Importantly, they studied not whether the approach could be made, but whether it could be done without causing harm to the patient.
“One of the risks of doing this decompression through the nose or skull is that you can violate the seals that hold the cerebrospinal fluid,” Dr. Andaluz says. “What we did was study specifically how much we can afford to decompress both from the transcranial and from the endonasal route without causing complications of cerebrospinal fluid leakage.”
Dr. Andaluz and his team concluded that the traditional approach provided neurosurgeons with “ample visualization and wide exposure,” while limiting the risk of causing a cerebrospinal fluid leak. The endonasal approach, by comparison, offered a narrower window of visibility. “Although endoscopic endonasal approaches have gained popularity, they may not always be what is best for an individual patient,” Dr. Andaluz says. “The real value here is to demonstrate both techniques and be able to offer the one that may more safely decompress the optic nerve without exposing the patient to excessive risks.”
In a second study, Dr. Andaluz and his colleagues studied orbital routes used to reach rare tumors of the orbital cavity and its surroundings inside the skull. They sought an optimal route that might reduce the amount of brain retraction and bone removal normally required. The surgeons drew on the experience of ophthalmologists to compare minimally invasive approaches into deep and complex regions of the central brain (the middle cranial fossa).
“We’ve seen techniques in those areas where you cannot get a good reach from either the nose or through the head,” Dr. Andaluz says. “We looked at different ways and different routes.”
Although the study is “very preliminary,” Dr. Andaluz says it gave the surgeons ideas about how to treat rare tumors in this hard-to-reach region by approaching through a small incision in the upper eyelid.
In a third study, Dr. Andaluz and his team combined established routes to orbital tumors into a novel, minimally invasive approach. The surgeons concluded that approaching tumors through a keyhole incision in the eyelid allowed good visualization of structures in the medial brain but that future studies were needed.
Dr. Andaluz says he wants his anatomical research to have practical, clinical implications. “I want to see how much I can do for my patient.”
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“Refining Operative Strategies for Optic Nerve Decompression: A Morphometric Analysis of Transcranial and Endoscopic Endonasal Techniques Using Clinical Parameters” was published in Operative Neurosurgery in March 2018. “Supraorbital vs Endo-Orbital Routes to the Lateral Skull Base: A Quantitative and Qualitative Anatomic Study” was published by Operative Neurosurgery in February 2018. “Endoscopic transorbital superior eyelid approach: anatomical study from a neurosurgical perspective” was published online in the Journal of Neurosurgery in December 2017.
Co-authors of the three research studies included Lee Zimmer, MD, PhD, of the Department of Otolaryngology-Head and Neck Surgery at the University of Cincinnati (UC), and Jeffrey T. Keller, PhD, of the UC Department of Neurosurgery. Steven Gogela, MD, a former neurosurgery resident at UC, was a co-author of the optic nerve decompression study. Researchers of the supraorbital vs endo-orbital study and the endoscopic transorbital superior eyelid approach study included Paolo Cappabianca, MD, of the Universita degli Studi di Napoli Federico II, of Naples, Italy.
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Mayfield Brain & Spine is the full-service patient care provider of the Mayfield Clinic, one of the nation’s leading physician organizations for neurosurgical treatment, education, and research. With more than 20 specialists in neurosurgery, interventional neuroradiology, physical medicine and rehabilitation, pain management, and physical therapy, Mayfield Brain & Spine treats 25,000 patients from 35 states and 13 countries in a typical year. Mayfield physicians specialize in the treatment of back and neck pain, sciatica, Parkinson’s disease, essential tremor, NPH, epilepsy, brain and spinal tumors, stroke, moyamoya, brain aneurysms, Chiari malformation, scoliosis, kyphosis, facial pain, facial twitch, trauma, concussion, spinal cord injury, and carpal tunnel. As leading innovators in their field, Mayfield physicians have pioneered surgical procedures and instrumentation that have revolutionized the medical art of neurosurgery for spinal diseases and disorders, brain tumors, and neurovascular diseases and disorders. For more information, visit www.MayfieldClinic.com.
Press release in English and translated to Spanish by MujerLatinaToday.com – Images credit: www.MayfieldClinic.com.
More information about this press release, please contact Cindy Starr, MSJ, Communications Department (513) 569-5236 cstarr@mayfieldclinic.com
