COMENTARIO
La hernia medular idiopática (HMI) es un hecho poco frecuente, de patogenia desconocida (aunque existen varias hipótesis al respecto) que se caracteriza por un desplazamiento ventral de la médula espinal a través de un defecto dural ventral o ventro-lateral, predominantemente en la columna torácica.1-3
En una revisión reciente1 se identificaron 159 tratados con cirugía y 15 casos tratados sin cirugía. La presencia de progresión en los síntomas mielopáticos sería el motivo por el cual se indicaría la cirugía, con una evolución favorable en algo más del 70% de los casos reportados.
La mayoría de las publicaciones son sobre casos aislados o series pequeñas de casos (no más de 12).1-3 Su historia natural no es muy conocida. Debido a ello, resulta difícil establecer una conducta de acuerdo con los postulados de la medicina basada en la evidencia. Las decisiones terapéuticas dependerían, entonces, del criterio médico, las experiencias pasadas y/o el estado del paciente en cada caso.
Los autores, Jacobo y col., han descripto 2 nuevos casos que, tanto en la clínica como en las imágenes, no se diferencian de los ya publicados. No explicaron por qué una HMI a nivel dorsal produciría compromiso de los miembros superiores; sería interesante conocer cómo podrían haberse afectado los dermatomas cervicales (¿tracción?, ¿isquemia?) en los casos descriptos.
Ellos optaron por no operarlos argumentando falta de evolutividad. Esta conducta tiene sustento en la bibliografía pero, de acuerdo con lo publicado recientemente, la decisión de no operar implica no mejorar en el 100% de los casos.1 Como los autores no hacen referencia al seguimiento, no sabemos durante cuánto tiempo han permanecido estables. En la literatura, el seguimiento promedio de los casos no operados fue de 33 meses, período durante el cual no hubo empeoramientos.1
La publicación de casos como éste, ayudan a mantenernos alertas sobre las patologías raras y a generar experiencia para saber cómo conducirnos.
Juan José Mezzadri
BIBLIOGRAFÍA
Palabras clave: Arteria Comunicante Anterior; Aneurisma Intracraneal; Abordaje Pterional
ABSTRACT
Objective: To analyze the chosen side in a pterional approach based on the position of the postcommunicating segment of anterior cerebral artery (A2) in a coronal plane, and its surgical requirements and complications.
Material and Method: A descriptive observational retrospective study has been designed. We analyzed 24 patients with anterior communicating artery aneurysms projecting superior and supero-anterior, who underwent microsurgical clipping between 2009-2014. This study includes 22 subarachnoid hemorrhages (91.67%) and 2 incidental aneurysms (8.33%). We studied the dominancy of the precommunicating segment (A1), A2 plane (open or closed) and the surgical requirements: gyrus rectus aspiration (GRA) or the need of fenestrated clips, and complications: cerebral contusion due to brain retraction, perforators' ischemia (PI) and residual neck.
Results: Out of the 24 patients, 12 (50%) were A2 open plane. Only 1 required GRA, 1 suffered perforators' ischemia and 2 had cerebral contusion. No fenestrated clip was used, and there was no residual neck. The remaining 12 patients (50%) had an A2 close plane. In this group, GRA was necessary in 8 cases and the use of fenestrated clip in 3. Perforators' ischemia was present in 3 cases, whereas another 3 patients suffered cerebral contusion and 1 had a residual neck (p=0.01).
Conclusion: We suggest that approaching anterior cerebral arteries aneurysms projecting superior and supero-anterior from an A2 open plane, allows an optimal anatomical exposure view with an adequate aneurysm clipping and reducing surgical complications.
Key words: Anterior Communicating Artery; Intracranial Aneurysm; Pterional Approach
]]>Palabras Claves: Fascículo de Meyer; Cirugía de Epilepsia; Campo Visual Computarizado; Tractografía por Tensor de Difusión
ABSTRACT
Objective: To describe the anatomy of the Meyer´s loop (ML) and the results of computerized visual field (CVF) and diffusion tensor tractography (DTT) to identify the damage of this fascicle in patients surgically treated for refractory epilepsy secondary to mesial-temporal sclerosis.
Introduction: Up to 80% of patients with temporo-mesial epilepsy associated with hippocampal sclerosis are refractory to medication. For these patients, surgery is a well established and effective treatment. However visual field defects are frequent by optic radiation´s injury after these procedures.
Materials and methods: We performed the dissection of white fibers on three human brains, previously fixed in formaldehyde, by Klingler´s technique, to recognize the fascicles that make up the visual pathway in the depth of the temporal lobe. Then, eight patients submitted to anterior temporal lobectomy and amygdalohippocampectomy were studied performing CVF and TTD at least 3 months after surgery. Individuals were classified into four groups according to visual field defects and other measurements in magnetic resonance imaging and tractography. Finally the results of the different variables were correlated and an extensive review of literature was performed.
Results: Using anatomical dissection the ML was identified as well as the rest of the fascicles and related structures to the visual pathway in the depth of the temporal lobe. All patients had some degree of visual field deficits. We couldn´t identify the leading edge of ML on the healthy side, however, the median position of the ML in the hemisphere without surgery (T-ML) was 29.6 mm. The median length measured from the anterior limit of the middle fossa to the posterior edge of the temporal resection was 37.8 mm. The median distance from the anterior limit of the middle fossa to the first identifiable bundle of white matter (A-SBI) was 33mm.
Conclusion: There is wide interindividual variation in the anterior extent of the ML, so the TTD focused on the temporal lobe is a potentially useful to assess individual risk of visual field defects in patients undergoing anterior temporal lobe surgery.
Key Words: Meyer´s Loop; Epilepsy Surgery; Computerized Visual Field; Diffusion Tensor Tractography
]]>Palabras Clave: Enfermedad de Parkinson; Subtalamotomía; Microrregistro
ABSTRACT
Introduction: In the treatment of advanced Parkinson´s disease (PD) there are different surgical techniques that represent a valid alternative. The development of modern images techniques and neurofisiological recording allow us to generate accurate lesions, with low complications and excellent functional results.
Objective: Describe motor results 12 months post-surgical of patients with advanced PD submitted to bilateral and deferred subthalamotomy guided by microrecording.
Material and Methods: We selected 9 patients with advanced PD diagnosis in concordance with United Kingdom Parkinson`s Disease Brain Bank criteria, evaluating the effects of bilateral subthalamotomy in two different surgical steps.
Results: A marked improvement of cardinal symptoms such as rigidity, bradykinesia and tremor was observed in all patients, fundamentally in “off” condition, and lesser extent in “on” condition. We highlighted a significant control of motor fluctuations and dyskinesias.
Conclusion: Bilateral and deferred suthalamotomy guided by microrecording is an effective and useful method in treatment of cardinal motor symptoms of PD.
Key words: Parkinson`s Disease; Subthalamotomy; Microrecording
]]>Palabras clave: Abordaje Pterional; Craneotomía Fronto-Temporo-Esfenoidal; Aneurismas
ABSTRACT
Objective: to report our surgical experience in the pterional approach, highlighting the extent and technical details of that procedure.
Material and Method: we performed a retrospective study analyzing the medical records of 142 patients who went under surgery through a classic pterional approach or one of its variants, between October 2009 and October 2012. Epidemiological data was collected and also that related to the different pathologies achieved by this route. For a better interpretation, the images were taken in 3D.
Results: during that period we performed 149 pterional craniotomies over a total of 145 patients, 4 of them underwent bilateral pterional approach. There were 95 patients with cerebral aneurysms, 9 of them with multiple aneurysmal disease. This approach allowed access for the surgical treatment of a total of 115 aneurysms, 37 of the communicating segment of the internal carotid artery, 29 of the medial cerebral artery, 26 of the anterior communicating artery, 7 of the carotid bifurcation, 6 of the ophthalmic segment of the internal carotid artery, 3 of the choroid segment, 2 paraclinoidal and 1 of the basilar artery bifurcation. Four were solved by high flow carotid-sylvian bypass. It was also achieved the excision of 45 tumors, 23 frontal, 5 temporal, 5 of the sphenoidal wing, 3 insular, 3 intraorbital, 3 pituitary macroadenomas, 2 craneopharingiomas and 1 optical nerve tumor. On the other hand, 4 patients with arteriovenous malformations went on surgery by this approach, 2 of insular location, 1 frontal and 1 temporal. A frontal cavernoma was also resected by this gateway. We formalized the following steps to perform the pterional approach: trichotomy and demarcation, patient and head positioning, incision, interfascial dissection, subperiostic section and dissection of the temporal muscle, craniotomy, dural attachment, drilling and dural opening.
Conclusion: the pterional craniotomy is a major gateway for solving a wide spectrum of diseases. The knowledge about the extent and technical details of this pathway is essential in daily neurosurgical practice, especially for neurosurgical interns.
Keywords: Pterional Approach; Fronto-Temporo-Sphenoidal Ccraniotomy; Aneurysms
]]>Palabras clave: Competencias Blandas; Generación Y; Liderazgo; Sociedad Moderna Líquida
ABSTRACT
The traditional highly centralized and authoritarian leadership challenged by the changes occurred in present society, educational opportunities, current generations and knowledge increase, has rendered inadequate. Modern society, considered “liquid” for the lack of certainties and its constant change in form and direction, defies experience as a valid mean to solve new problems. The great educational offer prevents that only one person will have the exclusiveness of professional training. “Y” generation, shaped by the distinctive features of its familiar environment and mainly by communicational technology, looks for direct and informal relationships, creating conflicts in the more authoritarian and hierarchical organizations. After modern scientific development, the great increase in knowledge and fragmentation impedes that somebody would pretend to know everything and turn to be the only source to recur. Perhaps the answer to these challenges may be the development of soft competences as share, empowerment, empathize and team work. The traditional leader, after losing knowledge and training exclusivity, should have to resign prominence and create more horizontal organizations in which every member will develop his competences and fulfill his objectives.
Keywords: Leadership; Modern Liquid Society; Soft Competencies; Y Generation
]]>Palabras clave: Abordaje; Anatomía; Cavernoma; Cuerno Temporal; Lóbulo Temporal
ABSTRACT
Objective: To describe the microsurgical anatomy and approaches to the mesial temporal region (MTR), in relation with cavernomas.
Material and Method: Five adult cadaveric heads, fixed in formol and injected with colored silicon were studied. Since January 2007 and June 2014, the author operated 7 patients with cavernomas located in the MTR.
Results: Anatomy: the MTR was divided in 3 portions: anterior, middle and posterior. Patients: the author operated 7 patients with MTR cavernomas. Four cavernomas were located in the anterior portion, 2 were located in the middle portion, and 1 cavernoma was located in the posterior portion. The transsylvian-transinsular approach was used for the anterior portion of the MTR; the transtemporal approach (anterior temporal lobectomy) was used for the middle portion of the MTR; and the supracerebellar-transtentorial approach was used for the posterior portion of the MTR.
Conclusion: The idea of divide the MTR in 3 portions help to select the correct approach.
Key words: Anatomy; Approach; Cavernoma; Temporal Horn; Temporal Lobe
]]>Palabras Claves: Neurorrafia con Tensión; Experimentación en Sistema Nervioso Periférico; Puntos Epineurales Distales; Injertos Nerviosos
ABSTRACT
Objective: To analyze, in a prospective way, the viability of a neurorraphy by a microsurgical technique, in an experimental model with different increasing grades of peripheral nerve tissue loss.
Introduction: In order to repair a peripheral nerve that has experienced some grade of substance loss, autologous grafts have been used by most neurosurgeons. However, comorbidities in the donor site are produced, and the results obtained are always inferior compared to the ones achieved by using a direct suture without tension. There is an option to avoid using grafts when the defect is scarce, which is the confection of distal epineural sutures (DES) to the neurorraphy, discarding any tension in this junction site.
Materials and methods: We have used 40 Wistar rats, randomly separated into 4 groups. In ‘Group A’, under complete anesthesia, the sciatic nerve was dissected and transversely sectioned and then sutured with a 10.0 nylon suture. Furthermore we made a 2 mm extirpation in ‘Group B’, a 4 mm one in ‘Group C’ and a 6 mm one in ‘Group C’, in order to perform a DES technique. Our group also ran a sciatic nerve function test (footprint analysis), conduction speed (by electrophysiology), and even determined the nerve regeneration index (histopathology) to estimate the viability of the neurorraphy. The different groups were confronted with ANOVA, considering a value of p<0.05 as statistically significative.
Conclusions: Simple neurorraphy exposed no statistically significative differences in comparison to the reparation of a 2 mm tissue loss with DES technique, in the Wistar rat model.
Key Words: Tension Neurorraphy; Peripheral Nervous System Experimentation; Distal Epineural Sutures; Nervous Grafts
]]>Palabras Claves: Aneurisma Cerebral; Aneurisma PICA; Abordaje Extremo Lateral; Circuito Posterior; Tratamiento Neuroquirúrgico
ABSTRACT
Objective: To describe the surgical treatment for complex, giant, embolized, PICA aneurysm and the follow up.
Description: 48 years old, female patient with clinical history of obstructive hydrocephalus and posterior fossa´s hipertension. The treatment was endovascular surgery with coils and venricular shunt with posterior fossa´s deccompresive surgery 4 years ago. The clinical evolution was poor. Due to low cranial nerves déficit and progressive posterior fossa´s hipertension, we performed microsurgical treatment
Intervention: We performed extreme lateral approach with partial drilling of occipital condile, wiht proper proximal vascular vertebral control, and vascular parietal artery reconstruction in the vertebral-posterior inferior cerebellar artery (PICA) aneurysmatic segment,with microsurgery, posterior opening of the dome and coils remotion.
Conclusion: Microsurgical treatment with reconstruction parietal technique, proximal vascular control and skull base approaches are the definitive and more adecuated treatment for giant PICA aneurysms.
Key Words: Cerebral Aneurysm; Pica Aneurysm; Extreme Lateral Approach; Posterior Circulation; Neurosurgical Treatment
Palabras Claves: Osteotomías Cervicales; Osteotomía De Ponte; Osteotomía 3D; Deformidad Cervical
ABSTRACT
Objective: To perform cervical osteotomies in cadaveric specimens, following the new classification of Ames et al. 3D pictures were taken to show the amount of bone resection on each subtype.
Material & methods: Using two formolized cadaveric specimens with vascular injection, we took 3D pictures of osteotomies following the Ames et al classification of cervical osteotomies. The pictures were taken with a Nikon D90 camera, with a 50 mm lens Af 1.8G, Nikon SB700 flash, and an adjustable titanium frame designed to take 3D pictures. Anterior cadaveric dissections were made based on the Smith & Robinson technique. We also performed a posterior approach to expose laminar surfaces, spinous processes, facets complexes, ligaments, discs, uncovertebral joints and vertebral bodies. With the aid of a pneumatic drill, 8 osteotomies (4 anterior and 4 posterior) were progressively made and pictured.
Results: The anterior osteotomies were: discectomy, corpectomy, discectomy with uncovertebral resection and spondilectomy. Posterior osteotomies were: partial facetectomy, complete facetectomy (Ponte), open wedge osteotomy and closing wedge osteotomy (pedicle substraction). Pictures were processed and fused with Anaglyph Maker 1.08 and StereoPhoto Maker 4.54.
Conclusions: Cervical osteotomies are useful surgical maneuvers to correct spinal deformities. 3D anatomy helps to understand the degree of bone resection needed to make each osteotomy, exposing nervous and vascular structures at risk in these procedures.
Key Words: Cervical Osteotomies; Ponte Osteotomy; 3D Osteotomies; Cervical Deformities
]]>Palabras clave: Abordaje Pterional; Base de Cráneo; Fisura Silviana; Microcirugía
ABSTRACT
Objective: the aim of this study is to describe, step by step, the pterional approach.
Description: position: the patient is placed supine, and the head rotated and also deflected. Incision: from the midline to de zygomatic arch, 1 cm in front of the tragus. Interfascial dissection: the landmarks: superficial temporal artery, orbital rim and zygomatic arch. The incision started at the level of the superior temporal line, 2 cm posterior to the orbital rim, and is pointed to the middle portion of the zygomatic arch. Temporal muscle displacement: after a transversal section of the upper portion of the muscle, it is detached in a subperiosteal fashion. Craniotomy: the osseous removal should expose the sylvian fissure and the middle and inferior frontal gyrus and also the superior temporal giri. Dural opening: in two flaps (frontal and temporal).
Conclusion: the pterional approach is still, nowadays, a valid and current technique. This approach allows treating many lesions located in the anterior and middle cranial fossa.
Keywords: Microsurgery; Pterional Approach; Skull Base; Sylvian Fissure
]]>Palabras clave: Metástasis Cerebral; Metástasis Solitaria; Metástasis Única; Tratamiento Multimodal; Radiocirugía; Radioterapia Holocraneal; Resección Quirúrgica
ABSTRACT
The treatment of Isolated Cerebral Metastatic Disease is both multimodal and palliative. At present, the optimal treatment protocol is unknown. The objective of the present study was to determine outcome differences between Whole Brain Radiotherapy (WBRT), Radiosurgery (RS), and Surgical Resection (SR) or a combination of them, regarding Global Survival, Functional Independent Survival, Local Control, Neurological Death & Cognitive Status in patients with a unique cerebral metastasis and a controlled primary tumor. A retrospective study with a systematic qualitative literature review was performed. Randomized clinical trials comparing surgery (with or without whole brain radiotherapy), disregarding the localization of the primary tumor, were searched, resulting in 971 studies, only 19 of them being randomized. After applying Cochrane´s Risk of Bias Tool, only 14 studies showed a low risk of bias. The combination of SR & WBRT showed a longer survival, while WBRT & RS showed a better local control when compared with SR & WBRT. No statistical differences where found between WBRT & RS versus RS alone. Results regarding Cognitive Status & Functional Independent Survival were inconsistent. The optimal treatment in Isolated Metastatic Cerebral Disease still remains controversial.
Key words: Cerebral metastasis, Isolated Metastasis, Unique Metastasis, Multimodal treatment, Radiosurgery, Whole Brain Radioterapia, Surgical Resection.
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