Resumen:

Actualmente, la psicocirugía (neurocirugía psiquiátrica) es un tratamiento muy selectivo y de mínima invasión que se aplica sólo en algunos pacientes con trastorno obsesivo-compulsivo, padecimientos esquizo afectivos, depresión mayor y ansiedad crónica, refractarios al tratamiento médico. Los avances recientes en tecnología, neuroanatomía y neurocirugía han permitido que la psicocirugía se considere una opción atractiva en el tratamiento de padecimientos psiquiátricos. Las tecnologías de cómputo permiten la planeación quirúrgica y la visualización necesarias para la cirugía guiada por imágenes.

Las imágenes por resonancia magnética (IRM) y tomografía por emisión de positrones (TEP) brindan información muy detallada de la estructura de los tejidos blandos del cerebro. Es posible visualizar alteraciones patológicas aun antes de que éstas puedan detectarse por cualquier otro medio. Los mapas estereotácticos resultantes de compilar esta información se utilizan para planear la operación y lograr la introducción en el cerebro de electrodos, cánulas y radiación ionizante con gran precisión.

También es posible obtener imágenes funcionales utilizando marcadores metabólicos especiales junto con la resonancia magnética y las técnicas computarizadas para el procesamiento matemático y la visualización de las imágenes. De este modo, la evaluación no invasiva de la función cerebral puede realizarse con precisión y sensibilidad extraordinarias.

La cirugía estereotáctica sin abrir el cráneo y sin sangrado (ni siquiera es necesario rasurar la cabeza del paciente) es posible gracias a una revolucionaria técnica denominada radiocirugía.

La destrucción del tejido nervioso o vascular dentro del cerebro se logra mediante la aplicación de rayos de radiación ionizante delgados y potentes, que provienen de diferentes ángulos alrededor de la cabeza del paciente y que convergen en un punto definido en tres dimensiones (estereotaxia) dentro del cerebro.

La radiación proviene de una fuente de cobalto radioactivo, el Gamma Knife, el cual fue desarrollado en la década de 1960 por el neurocirujano sueco Lars Leksell.

En nuestro país, en 1996 se empezó a usar la radiocirugía gamma para tratar a pacientes con trastornos psiquiátricos resistentes al tratamiento médico, gracias al trabajo multidisciplinario de psiquiatras, neuropsicólogos, neurólogos, neurocirujanos y físicos médicos.

De acuerdo con los lineamientos del protocolo de neurocirugía psiquiátrica de Médica Sur, en estricto apego a su Código de Ética y a los lineamientos de la Comisión Nacional de Seguridad Nuclear y Salvaguardas, y las recomendaciones de la Sección de Neurorradiocirugia y Radioterapia Estereotáctica del Colegio Mexicano de Cirugía Neurológica, hasta la fecha se han realizado procedimientos de cingulotomia, capsulotomia anterior, tractotomia subcaudada y leucotomía límbica para tratar a pacientes con trastorno obsesivo-compulsivo, depresión mayor, agresividad patológica y síndromes de Asperger y de Gilles de la Tourette.

Los pacientes se categorizan de acuerdo con la evaluación multiaxial del Manual Diagnóstico y Estadístico de los Trastornos Mentales (DSM-IV), y reciben el tratamiento en la unidad de radiocirugía Gamma knife. Lo anterior se realiza habitualmente con anestesia local y sedación superficial, sin ingresar a los pacientes al hospital, quienes regresan el mismo día del tratamiento a su lugar de procedencia. Presentamos aquí los resultados obtenidos en una serie de nueve pacientes con un seguimiento mínimo de seis meses y un máximo de siete años de acuerdo con las escalas habituales de evaluación para este tipo de problemas.

Palabras clave: Psicocirugía; radiocirugía; Gamma knife; estereotaxia

Abstract:

Today, psychosurgery is a minimally invasive and highly selective treatment performed only on some patients with severe, refractory treatment, affective, anxious, or obsessive-compulsive disorders. Recent advancements in technology and functional neuroanatomy as well as economic pressures to lower the cost of caring for the chronically ill may provide an opportunity for psychosurgery to become a more attractive option in the treatment of psychiatric disease.

In recent years, the rapid adoption of computer-based techniques for surgical planning and visualization and image-guided surgery have made possible a number of impressive advances in functional neurosurgery.

Magnetic resonance imaging (MRI) allows for the acquisition of highly detailed structural information of soft tissues in the brain. Minute pathological alterations can be visualized even before they are detected by other means. Stereotaxic atlases based on this information are now used to achieve an extraordinary precision in the placement of electrodes and probes and to plan the operation.

Functional imaging is currently possible with special metabolic markers and MRI, as well as computerized techniques for the mathematical processing and visualization of images. Thus, non-invasive evaluation of brain function can be performed with extraordinary precision and sensitivity.

Bloodless stereotaxic surgery without opening the skull (even the patient's head does not need to be shaved) is possible thanks to a revolutionary technique called radiosurgery. The destruction of nervous or vascular tissue inside the brain is achieved by projecting thin and powerful beams of ionizing radiation, which come from several angles around the patient's head. These beams produced by sources of radioactive cobalt (the "gamma knife" developed in the 60's by the Swedish neurosurgeon Lars Leksell). With this modality, radiation energy concentrates in a single small point inside the brain.

Gamma Knife radiosurgery was first used in our country in 1996 to treat patients diagnosed with treatment-refractory psychiatric diseases. This treatment modality requires a multidisciplinary effort on the part of psychiatrists, neuropsychologists, neurologists, neurosurgeons and medical physicists. This should also be in accordance with the psychiatric neurosurgical protocol and ethics code of Medica Sur, as well as following the guidelines established by the National Nuclear

Regulatory Commission and the Radiosurgery and Stereotaxic Radiotherapy Section of the Mexican College of Neurological Surgery. Ten patients have been treated with several procedures like cingulotomy, anterior capsulotomy, subcaudate tractotomy and limbic leukotomy in order to aid them in obsessive-compulsive disorder, major depression, pathological aggression, and Asperger and Tourette Syndromes.

In this paper we disclose our experience with follow-ups ranging from six months to seven years in accordance with the most usual evaluation scales for mental disease and multiaxial evaluation framework of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).

In our cases, the most common indications have been refractory obsessive-compulsive disorder (OCD), pathologic aggression and major depression after at least two years of treatment and with the involvement of at least two psychiatrists.

According to the basal diagnosis, psychological tests are used by the neuropsychology specialist from our group and /or the neuropsychologists who have given medical treatment along with the psychiatrists.

Six males and four females were treated with an age range of 13 to 52 years, and an average age of 28.2 years.

The first patient had impulsive disorder and hetero-aggression, with a history of two bilateral prefrontal lobotomies with no stereotaxic planning and without a good response. The patient had gamma radiosurgery with bilateral anterior capsulotomy and continued his antipsychotic treatment. For two years, the patient had a good response and was able to go back to his wife and mother. After those two years, he developed a hypersexuality syndrome that led to a divorce from his wife and the patient was lost to clinical follow-up.

The second patient was an adolescent with corpus callosum lipoma and hetero-aggression and compulsive syndrome refractory to medical treatment including carbamazepine levels above the therapeutic level. Three persons had to continuously watch him at home during 24 hours a day. He had a history of bilateral stereotaxic cingulotomy with thermocoagulation without a good response. Under general anesthesia, a gamma bilateral stereotaxic capsulotomy was performed. After 2 months of latency period and three years of follow-up, the hetero-aggression has been under control. Carbamazepine treatment is still used.

The third patient had physical hetero-aggression towards his parents for more than seven years. He underwent gamma radiosurgery for bilateral capsulotomy and after a latency period of three months and a three year follow-up the patient has had no aggression episodes.

The fourth patient had hetero-aggression since his teenage years, with a course of more than 6 years of this disorder and major depression with suicidal attempts. He had an electroconvulsive therapy session that led to a minor improvement lasting 2 months. Gamma radiosurgery was used for a limbic leukotomy in the cingula and the anterior arm of the internal capsules. His aggressiveness has significantly improved and his depression has been fluctuating under medical supervision. The patient has anxiety crisis that the patient's mother helps to control by giving him marijuana.

The fifth patient had OCD of more than 10 years of course and a predominance of contamination fobias and bleeding hands because of frequent washing. She was treated with bilateral gamma capsulotomy and after two months of latency she stopped using gloves and after two years of follow-up the fobias have disappeared and has been able to work with no limitations in a company office.

The sixth adolescent patient is the son of a neurosurgeon colleague and has symptoms of hetero and self-aggression, impulsivity and destructive behavior associated with mental retardation. The patient underwent a bilateral anterior capsulotomy under general anesthesia. The suggested treatment protocol was to combine the procedure with bilateral limbic leukotomy and hypothalamic procedure in a second surgical stage to control the self-aggression outbreaks. The patient had significant improvement of his impulsivity during the first two months and before the end of his minimum latency period of 6 to 8 months developed a zone of radionecrosis. He had an open cingulotomy after five months of radiosurgery in another hospital and his current clinical course is unknown.

The seventh patient with Asperger and Tourette syndrome and impulsivity and hetero-aggression had a bilateral anterior gamma capsulotomy with significant improvement and after one year of follow-up he had a less severe clinical recurrence and underwent bilateral gamma cingulotomy to complete limbic leukotomy. He has early shown improvement but his follow-up is only two months.

The eighth patient had schizophrenic disorder displayed as impulsivity crisis, obsessive ideas and hetero-aggression towards his family fluctuating with periods of depression. He had a limbic leukotomy and has good control of his aggression and is still under medical treatment as most of the patients are.

The nineth patient in the series had major depression, suicidal attempts and chronic anxiety refractory to medical treatment. She was operated two years before and had a bilateral capsulotomy by thermocoagulation and because her clinical picture prevailed, she had bilateral anterior capsulotomy with gamma knife. In her six month follow-up, her anxiety has improved, and she has had no new major depression crisis and her follow-up neuropsychological tests are pending to be made in her home town.

Key words: Psychosurgery; radiosurgery; gamma knife; stereotaxy