[Subthalamic nucleus targeting and spatial variability]. / Localización bilateral y simetría del núcleo subtalámico.

AIM: The effectiveness of anatomic localization of the subthalamic nucleus (EAL) was assessed and the mapping method is described here. The symmetry of contralateral nuclei (SCN) was analyzed on 11 parkinsonian patients submitted to bilateral subthalamotomy with ablative lesioning. PATIENTS AND METHODS: To assess EAL the percentage so much of first trajectory (p1) as the total of trajectories (pt) that hit the target and the rest of subthalamic nucleus average distance (d) was calculated. The anatomic localization error (epsilon) is determined as a difference between first trajectory coordinates with those of medial determined nucleus point, through electrophysiological data as to the statistical significance of this error. SCN is analyzed by contrasting equality hypothesis at the nucleus maximum height alongside a trajectory, average electrophysiological position center and spatial distribution of all intranuclear recordings found in each hemisphere in all patients. RESULTS: The pi, pt and d obtained values were 86.36%, 86.13% and 1.41 +/- 1.01 mm respectively. The epsilon value was greater in anteroposterior direction of 1.11 +/- 0.83 mm without statistical significance. The average number of recorded trajectories for the first procedure was 6.45 and 6 for the second. The asymmetry of contralateral nucleus was not significant. CONCLUSIONS: An indirect method with CT brain images and a new electrophysiological mapping method with a multiunitary recording for first and second nucleus is safe enough and it yields a high effectiveness in anatomofunctional nucleus localization. The nucleus of a same patient are symmetrical. There is little space variability among patient non related to the differences in the intercommissural distance.

[Osteochondroma of the atlantooccipital joint. Extreme lateral transcondylar approach. A case description]. / Osteocondroma de la articulación atlantoccipital. Abordaje extremo lateral transcondilar. A propósito de un caso.

INTRODUCTION: We describe a patient diagnosed as suffering from a skull base osteochondroma which affected the atlantooccipital joint and originated in the occipital condyle. It also displayed a growth toward the foramen magnum, which was resected using an extreme lateral transcondylar approach. CASE REPORT: Patient aged 35, with a one year history of vertiginous seizures and unsteady gait, associated with cervical pain that irradiated to the right upper extremity, dysphagia, changes in the tone of the voice and distal numbness of the four extremities. The patient was made to lie in the three quarter prone position and an incision was made in the skin from the C3 spinous apophysis to a point 2 cm below the end of the mastoid process, in relation with the transversal apophysis of C1. The intervention continued with early identification and rotation of the vertebral artery; total resection of the tumour (osteochondroma) with its base in the right occipital condyle and growth toward the foramen magnum, in which the greater resection of the posteromedial third of the condyle is included. CONCLUSIONS: The location of osteochondromas can vary widely, and the condyle is one of the least frequent places inside the occipital bone. The approach employed provides excellent access to the region, in particular to the atlantooccipital joint. The width and angle of exposition are increased as compared with the traditional suboccipital approach, which facilitates the radical resection of the lesion with no neural retraction and without any surgical complications.

[Stereotaxic microsurgical resection of intracranial tumors guided by imaging and assisted by computer]. / Resección microquirúrgica estereotáxica de tumores intracraneales guiada por imagen y asistida por computadora.

INTRODUCTION: The microsurgical techniques for resection of intracranial lesions are limited where anatomical references do not exist or cannot be used as guides in the dissection of deeply located lesions or in more superficial eloquent areas. The stereotaxic guide, guided by imaging gives precise volumetric and geometric definition in intracranial lesions. Its application in the resection of intracranial tumors has special characteristics due to their biological condition and varied localization. OBJECTIVES: Spatial orientation during surgery is essential. We show this application of stereotaxic surgery in the Centro Internacional de Restauración Neurológica (CIREN) in La Havana, Cuba, between May 1994 and February 1988, describing 65 microsurgical operations done using stereotaxis in 62 patients with intracranial cerebral tumors. PATIENTS AND METHODS: The procedure was divided into three stages: acquiring an image, computerized axial tomography and surgical planning, with the STASSIS planning system and microsurgical procedures, including systems of stereotaxis: Leksell, Micromar and Estereoflex. RESULTS: Of the total, 27 of these patients had glial tumors, 33 non-glial tumors and only 2 had non-neoplastic lesions of different sites and sizes. A total of 30 resections were done. Surgical morbidity was minimal and there was no surgical mortality. CONCLUSIONS: The main advantages of this method are: exact localization of the site for craniotomy, easy spatial orientation and ease in distinguishing the delimitation between the tumour and the healthy tissue. It has been shown that Estereoflex may be used in cerebral microsurgery.

[Bilateral cyclic sciatica caused by endometriosis. Apropos of a case]. / Ciática cíclica bilateral por endometriosis. A propósito de un caso.

INTRODUCTION: Cyclical sciatica due to implantation of endometrial tissue in the sciatic nerve in the region of the sciatic notch is a very unusual cause of sciatica. It occurs in women of childbearing age, as episodes of pain in the distribution of the sciatic nerve, which present in a cyclic manner and coincide with menstruation. If it is not treated, a sensomotor mononeuropathy of the sciatic nerve develops. CLINICAL CASE: The patient had complained of right-sided sciatic pain from the age of 36 years. Over the years a motor deficit had slowly and progressively appeared causing foot drop. The painful crises were related to her menstrual periods. At the age of 44 years a pyramidal muscle syndrome was diagnosed and treated surgically. This was followed by increase in the crises of sciatic pain. A year later, she started to have sciatic pain on the left side, which was similar to that of the right side. The clinical, imaging and electrophysiological findings are reported. The patient improved. She is still being treated with depot medroxyprogesterone and her pain has disappeared. CONCLUSIONS: Cyclical sciatica due to endometriosis is little known and may lead to permanent disability. Computerized axial tomography of the pelvis using contrast material is very useful for diagnosis. The use of depot medroxyprogesterone seems to be a satisfactory treatment in some patients.