The Smith-Robinson Approach to the Subaxial Cervical Spine: A Stepwise Microsurgical Technique Using Volumetric Models From Anatomic Dissections.

BACKGROUND: The Smith-Robinson1 approach (SRA) is the most widely used route to access the anterior cervical spine. Although several authors have described this approach, there is a lack of the stepwise anatomic description of this operative technique. With the advent of new technologies in neuroanatomy education, such as volumetric models (VMs), the understanding of the spatial relation of the different neurovascular structures can be simplified. OBJECTIVE: To describe the anatomy of the SRA through the creation of VMs of anatomic dissections. METHODS: A total of 4 postmortem heads and a cervical replica were used to perform and record the SRA approach to the C4-C5 level. The most relevant steps and anatomy of the SRA were recorded using photogrammetry to construct VM. RESULTS: The SRA was divided into 6 major steps: positioning, incision of the skin, platysma, and muscle dissection with and without submandibular gland eversion and after microdiscectomy with cage positioning. Anatomic model of the cervical spine and anterior neck multilayer dissection was also integrated to improve the spatial relation of the different structures. CONCLUSION: In this study, we review the different steps of the classic SRA and its variations to different cervical levels. The VMs presented allow clear visualization of the 360-degree anatomy of this approach. This new way of representing surgical anatomy can be valuable resources for education and surgical planning.

Microsurgical Anatomy of the Insular Region and Operculoinsular Association Fibers and its Neurosurgical Application.

OBJECTIVE: To analyze the three-dimensional relationships of the operculoinsular compartments, using standard hemispheric and white matter fiber dissection and review the anatomy of association fibers related to the operculoinsular compartments of the Sylvian fissure and the main white matter tracts located deep into the insula. The secondary aim of this study was to improve the knowledge on this complex region to safely address tumor, vascular, and epilepsy lesions with an integrated perspective of the topographic and white matter fiber anatomy using 2D and 3D photographs. METHODS: Six cadaveric hemispheres were dissected. Two were fixed with formalin and the arteries were injected with red latex dye; the remaining four were prepared using the Kingler method and white fiber dissections were performed. RESULTS: The insula is located entirely inside the Sylvian fissure. The topographic hemispheric anatomy, Sylvian fissure, opercula, surrounding sulci and gyri, as well as the M2, M3, and M4 segments were identified. The anatomy of the insula, with the sulci and gyri and the limiting sulci, were also identified and described. The main white matter fiber tracts of the operculoinsular compartments of the Sylvian fissure as well as the main association and commissural fibers located deep in the insula were dissected and demonstrated. CONCLUSIONS: Complementing topographic anatomy with detailed study of white matter fibers and their integration can help the neurosurgeon to safely approach lesions in the insular region, improving postoperative results in the microsurgical treatment of aneurysmal lesions, insular tumors, or epilepsy surgery.

Using NMR in saliva to identify possible biomarkers of glioblastoma and chronic periodontitis.

Nowadays there is increasing interest in identifying-and using-metabolites that can be employed as biomarkers for diagnosing, treating and monitoring diseases. Saliva and NMR have been widely used for this purpose as they are fast and inexpensive methods. This case-control study aimed to find biomarkers that could be related to glioblastoma (GBL) and periodontal disease (PD) and studied a possible association between GBL and periodontal status. The participants numbered 130, of whom 10 were diagnosed with GBL and were assigned to the cases group, while the remaining 120 did not present any pathology and were assigned to the control group. On one hand, significantly increased (p < 0.05) metabolites were found in GBL group: leucine, valine, isoleucine, propionate, alanine, acetate, ethanolamine and sucrose. Moreover, a good tendency to separation between the two groups was observed on the scatterplot of the NMR. On the other hand, the distribution of the groups attending to the periodontal status was very similar and we didn´t find any association between GBL and periodontal status (Chi-Square 0.1968, p = 0.91). Subsequently, the sample as a whole (130 individuals) was divided into three groups by periodontal status in order to identify biomarkers for PD. Group 1 was composed of periodontally healthy individuals, group 2 had gingivitis or early periodontitis and group 3 had moderate to advanced periodontitis. On comparing periodontal status, a significant increase (p < 0.05) in certain metabolites was observed. These findings along with previous reports suggest that these could be used as biomarkers of a PD: caproate, isocaproate+butyrate, isovalerate, isopropanol+methanol, 4 aminobutyrate, choline, sucrose, sucrose-glucose-lysine, lactate-proline, lactate and proline. The scatter plot showed a good tendency to wards separation between group 1 and 3.

[Cranial trepanation in primitive cultures]. / La trepanación craneal en las culturas primitivas.

A review is presented on cranial trepanations performed by primitive cultures. The scientific interest in this topic began after the discovery in 1965 by Ephraim G. Squier of a pre-Columbian trepanated skull, and studied by Paul Broca in Paris. Pseudotrepanation and other types of cranial manipulation are reviewed. The techniques, technology, and instruments for every type of trepanation are well known. There are a surprisingly high percentage of cases showing signs of post-trepanation survival. Indications for trepanation are speculative, perhaps magic. Although trepanation in primitive cultures is widespread around the world, and throughout time, the main fields of interest are the Neolithic Period in Europe, the pre-Columbian Period in Andean South America, and some contemporaneous Pacific and African tribes. This particular trepanation procedure has no relationship with modern Neurosurgery, or with trepanations with therapeutic purposes performed since the Greco-Roman period in Europe, and afterwards around the world.

[History of the craniotomy]. / Historia de la craneotomía.

Craniotomy can be defined as the neurosurgical procedure aimed at achieving a wide cranial opening with the final purpose of performing a surgical therapeutic manoeuvre within the intracranial space. The current surgical technique for craniotomy is the final result of the development of the procedure since its introduction at the end of the 19th century. The very first wide cranial approach was introduced in 1889 by Wagner, and described as a 'temporary cranial resection'. This procedure could be named today as 'osteoplastic craniotomy with pedicle bone flap'. The final result of the procedural development of the craniotomy is the 'osteoplastic craniotomy with free bone flap', used widely around the world. In this paper, we review the historic evolution of craniotomy from a technical perspective.

[Prognostic variability in atypical meningioma with complete resection. Proposed treatment algorithm]. / Variabilidad pronóstica del meningioma atípico con resección completa. Propuesta de algoritmo de tratamiento.

OBJECTIVE: The authors attempt to show how the current prognostic factors that try to assess the risk of recurrence of atypical meningiomas are insufficient to predict the future of this disease. MATERIALS AND METHOD: Using data obtained from hospital databases, a sample of 27 patients was obtained with pathological diagnosis of atypical meningioma, and who had a minimum follow-up time of 6months after diagnosis. Later prognostic factors (age <50years, male gender, bone involvement, peri-lesional swelling, tumour volume, location, Ki67/MIB-1) were evaluated after the stratification of patients undergoing complete resection in recurrencies and non-recurrencies. Univariate analysis was performed using Mann-Whitney test, χ(2) homogeneity test/Fisher exact test. Finally, multivariate analysis was performed using binary logistic regression to obtain the values for R(2) Nagelkerke and the Hosmer-Lemeshow to evaluate the goodness of fit. RESULTS: The uni- and multivariate analysis showed no statistically significant differences between recurrent and non-recurrent subgroups of patients undergoing complete resection. It is noted in the results that for each year of age above 50 years, the risk of recurrence is decreased by 5.8%. CONCLUSIONS: Although current prognostic factors may show an increased risk of recurrence once patients are stratified by the two most important factors (pathology and extent of resection), those factors are insufficient to predict the ultimate outcome of patients affected by this pathology.

[Spinal cord stimulation and failed back surgery syndrome. Clinical results with laminectomy electrodes]. / Estimulación medular crónica y síndrome de cirugía de espalda fallida. Resultados clínicos con la utilización de electrodos planos quirúrgicos.

INTRODUCTION: Spinal cord stimulation is a widely-accepted technique in the treatment of back pain resulting from failed back surgery. Classically, stimulation has been carried out with percutaneous electrodes implanted under local anaesthesia and sedation. However, the ease of migration and the difficulty of reproducing electrical paresthesias in large areas with such electrodes has led to increasing use of surgical plate leads, which have the disadvantage of the need for general anaesthesia and a laminectomy for implantation. OBJECTIVES: Our objective was to report the clinical results, technical details, advantages and benefits of laminectomy lead placement under epidural anaesthesia in failed back surgery syndrome cases. MATERIAL AND METHODS: Spinal cord stimulation was performed in a total of 119 patients (52 men and 67 women), aged between 31 and 73 years (average, 47.3). Epidural anaesthesia was induced with ropivacaine. In all cases we inserted the octapolar or 16-polar lead in the epidural space through a small laminectomy. The final position of the leads was the vertebral level that provided coverage of the patient's pain. The electrodes were connected at dual-channel or rechargeable pulse generators. RESULTS: After a mean follow-up of 4.7 years, the results in terms of improvement of the previous painful situation was satisfactory, with an analgesia level of 58% of axial pain and 60% of radicular pain in more than 70% of cases. None of the patients said that the surgery stage was painful or unpleasant. No serious complications were included in the group, but in 6 cases the system had to be explanted because of ineffectiveness or intolerance of long-term neurostimulation. CONCLUSIONS: This study, with a significant number of patients, used epidural anaesthesia for spinal cord stimulation of lead implants by laminectomy in failed back surgery syndromes. The technique seems to be safe and effective.

Magnetic resonance microscopy at 14 Tesla and correlative histopathology of human brain tumor tissue.

Magnetic Resonance Microscopy (MRM) can provide high microstructural detail in excised human lesions. Previous MRM images on some experimental models and a few human samples suggest the large potential of the technique. The aim of this study was the characterization of specific morphological features of human brain tumor samples by MRM and correlative histopathology. We performed MRM imaging and correlative histopathology in 19 meningioma and 11 glioma human brain tumor samples obtained at surgery. To our knowledge, this is the first MRM direct structural characterization of human brain tumor samples. MRM of brain tumor tissue provided images with 35 to 40 µm spatial resolution. The use of MRM to study human brain tumor samples provides new microstructural information on brain tumors for better classification and characterization. The correlation between MRM and histopathology images allowed the determination of image parameters for critical microstructures of the tumor, like collagen patterns, necrotic foci, calcifications and/or psammoma bodies, vascular distribution and hemorrhage among others. Therefore, MRM may help in interpreting the Clinical Magnetic Resonance images in terms of cell biology processes and tissue patterns. Finally, and most importantly for clinical diagnosis purposes, it provides three-dimensional information in intact samples which may help in selecting a preferential orientation for the histopathology slicing which contains most of the informative elements of the biopsy. Overall, the findings reported here provide a new and unique microstructural view of intact human brain tumor tissue. At this point, our approach and results allow the identification of specific tissue types and pathological features in unprocessed tumor samples.

Metabolic aggressiveness in benign meningiomas with chromosomal instabilities.

Meningiomas are often considered benign tumors curable by surgery, but most recurrent meningiomas correspond to histologic benign tumors. Because alterations in chromosome 14 among others have suggested clinical aggressiveness and recurrence, determining both the molecular phenotype and the genetic profile may help distinguish tumors with aggressive metabolism. The aim of this study was to achieve higher specificity in the detection of meningioma subgroups by measuring chromosomal instabilities by fluorescence in situ hybridization and cytogenetics and metabolic phenotypes by high-resolution magic angle spinning spectroscopy. We studied 46 meningioma biopsies with these methodologies. Of these, 34 were of WHO grade 1 and 12 were of WHO grade 2. Genetic analysis showed a subgroup of histologic benign meningioma with chromosomal instabilities. The metabolic phenotype of this subgroup indicated an aggressive metabolism resembling that observed for atypical meningioma. According to the metabolic profiles, these tumors had increased energy demand, higher hypoxic conditions, increased membrane turnover and cell proliferation, and possibly increased resistance to apoptosis. Taken together, our results identify distinct metabolic phenotypes for otherwise benign meningiomas based on cytogenetic studies and global metabolic profiles of intact tumors. Measuring the metabolic phenotype of meningioma intact biopsies at the same time as histopathologic analysis may allow the early detection of clinically aggressive tumors.