The foramen lacerum: surgical anatomy and relevance for endoscopic endonasal approaches.

OBJECTIVEThe foramen lacerum is a relevant skull base structure that has been neglected for many years. From the endoscopic endonasal perspective, the foramen lacerum is a key structure due to its location at the crossroad between the sagittal and coronal planes. The objective of this study was to provide a detailed investigation of the surgical anatomy of the foramen lacerum and its adjacent structures based on anatomical dissections and imaging studies, propose several relevant key surgical landmarks, and demonstrate the surgical technique for its full exposure with several illustrative cases.METHODSTen colored silicone-injected anatomical specimens were dissected using a transpterygoid approach to the foramen lacerum region in a stepwise manner. Five similar specimens were used for a comparative transcranial approach. The osseous anatomy was examined in 32 high-resolution multislice CT studies and 1 disarticulated skull. Representative cases were selected to illustrate the application of the findings.RESULTSThe pterygosphenoidal fissure is the synchondrosis between the lacerum process of the pterygoid bone and the floor of the sphenoid bone. It constantly converges with the posterior end of the vidian canal at a 45° angle, and its posterolateral end points directly to the lacerum foramen. The pterygoid tubercle separates the vidian canal from the pterygosphenoidal fissure, and forms the anterior wall of the lower part of the foramen lacerum. The lingual process, which forms the lateral wall of the foramen lacerum, was identified in 53 of 64 sides and featured an average height of 5 mm. The mandibular strut separates the foramen lacerum from the foramen ovale and had an average width of 5 mm.CONCLUSIONSThis study provides relevant surgical landmarks and a systematic approach to the foramen lacerum by defining anterior, medial, lateral, and inferior walls that may facilitate its safe exposure for effective removal of lesions while minimizing the risk of injury to the internal carotid artery.

Fully Endoscopic Minimally Invasive Transrectus Capitis Posterior Muscle Triangle Approach to the Posterolateral Condyle and Jugular Tubercle.

Background We evaluated a transrectus capitis posterior muscle triangle approach to the posterolateral foramen magnum, occipital condyles, jugular tubercle, and the fourth ventricle. We also assessed factors that affect the amount of bone removal required. Objective To evaluate if the proposed approach is as effective as standard open approaches to expose the lateral portion of the foramen magnum. Methods The proposed minimally invasive fully endoscopic approach was performed in 15 cadaveric specimens using 4-mm (0- and 45-degree) endoscopes. Results Using a 5-cm straight paramedian incision, the rectus capitis posterior minor and major muscles were partially removed unilaterally, providing a corridor through the muscles to reach the foramen magnum region. After meticulous soft tissue dissection, key anatomical landmarks can be identified such as the greater occipital nerve, the vertebral artery that wraps around the atlanto-occipital joint, and the bony protuberance that heralds the occipital condyle. A suboccipital craniotomy associated with the transcondylar, supracondylar or paracondylar approach is performed depending on the amount of bone removal desired to maximize the surgical view. By doing so, the jugular foramen can be exposed laterally as well as the fourth ventricle medially. Conclusion The proposed endoscopic approach can provide access through the transrectus capitis posterior muscle triangle leading directly to the occipital condyle. A stepwise approach is critical to gain a surgical corridor to the inferolateral petroclival region and the fourth ventricle.

Interfascial Dissection for Protection of the Nerve Branches to the Frontalis Muscles during Supraorbital Trans-Eyebrow Approach: An Anatomical Study and Technical Note.

Introduction Preservation of the temporal branches of the facial nerve during anterolateral craniotomies is important. Damaging it can inflict undesirable cosmetic defects to the patient. The supraorbital trans-eyebrow approach (SOTE) is a versatile keyhole craniotomy but still has a high rate of frontalis muscle (FM) palsy. Objective Anatomical study to implement the interfascial dissection during the SOTE to preserve the nerves to the FM. Methods Slight modification of the standard technique of the SOTE was performed in 6 cadaveric specimens (12 sides). Results Distal rami to the FM were exposed. The standard "u-shape" incision of the FM can cross over the nerves. Alternatively, an "l-shape" incision was performed until the superior temporal line (STL). An interfascial dissection was performed near to the STL and the interfascial fat pad was used as a protective layer for the nerves. Conclusion Various pathologies can be addressed with the SOTE. In the majority of the cases the cosmetic results are good, but FM palsy remains a drawback of this approach. The interfascial dissection may be used in an attempt to prevent frontalis rami palsy.

3-D simulation of posterior fossa reduction in Chiari I.

We proposed a 3D model to evaluate the role of platybasia and clivus length in the development of Chiari I (CI). Using a computer aided design software, two DICOM files of a normal CT scan and MR were used to simulate different clivus lengths (CL) and also different basal angles (BA). The final posterior fossa volume (PFV) was obtained for each variation and the percentage of the volumetric change was acquired with the same method. The initial normal values of CL and BA were 35.65 mm and 112.66º respectively, with a total PFV of 209 ml. Ranging the CL from 34.65 to 29.65 - 24.65 - 19.65, there was a PFV decrease of 0.47% - 1.12% - 1.69%, respectively. Ranging the BA from 122.66º to 127.66º - 142.66º, the PFV decreased 0.69% - 3.23%, respectively. Our model highlights the importance of the basal angle and clivus length to the development of CI.

3-D simulation of posterior fossa reduction in Chiari I / Simulação em 3D da redução da fossa posterior no Chiari do tipo I

ABSTRACT We proposed a 3D model to evaluate the role of platybasia and clivus length in the development of Chiari I (CI). Using a computer aided design software, two DICOM files of a normal CT scan and MR were used to simulate different clivus lengths (CL) and also different basal angles (BA). The final posterior fossa volume (PFV) was obtained for each variation and the percentage of the volumetric change was acquired with the same method. The initial normal values of CL and BA were 35.65 mm and 112.66º respectively, with a total PFV of 209 ml. Ranging the CL from 34.65 to 29.65 – 24.65 – 19.65, there was a PFV decrease of 0.47% – 1.12% – 1.69%, respectively. Ranging the BA from 122.66º to 127.66º – 142.66º, the PFV decreased 0.69% – 3.23%, respectively. Our model highlights the importance of the basal angle and clivus length to the development of CI.

RESUMO No presente estudo, propusemos a criação de um modelo computacional em 3D com elaboração de software onde dois arquivos em formato DICOM com uma TC e RNM de crânio foram usados para simular diferentes mensurações na extensão do clivus (EC) e no ângulo basal (AB). O volume final da fossa posterior (VFP) foi obtido em cada variação, bem como a percentagem de volume alterada. O tamanho inicial da EC era de 35,65 mm e o do AB era de 112.66º, com um VFP de 209 ml. Variando a EC de 34,65 para 29,65 – 24.65 e 19.65, houve uma diminuição do VFP de 0.47%, 1.12% e 1.69%, respectivamente. Variando o AB de 122,66º para 127,66º e 142,66º, o VFP diminui para 0.69% e 3.23%, respectivamente. Nosso modelo enfatiza a importância da patogênese do aumento do AB e do encurtamento do clivus no desenvolvimento do Chiari I.

"Next Door" intraoperative magnetic resonance imaging for awake craniotomy: Preliminary experience and technical note.

BACKGROUND: During glioma surgery "maximal safe resection" must be the main goal. Intraoperative magnetic resonance imaging (iMRI) associated with awake craniotomy (AC) is a valuable tool to achieve this objective. In this article, AC with a "next-door" iMRI concept is described in a stepwise protocol. METHODS: This is a retrospective analysis of 18 patients submitted to AC using iMRI; a stepwise protocol is also discussed. RESULTS: The mean age was 41.7 years. Hemiparesis, aphasia, and seizures were the main initial symptoms of the patients. Sixty-six percent of the tumors were located in the left hemisphere. All tumors were near or within eloquent areas. Fifty-three percent of the cases were glioblastomas multiforme and 47% of the patients had low grade gliomas. The mean surgical time and iMRI time were 4 h 4 min and 30 min, respectively. New resection was performed in 33% after iMRI. Extent of resection (EOR) higher than 95% was possible in 66.7% of the patients. The main reason of EOR lower than 95% was positive mapping of eloquent areas (6 patients). Eighty percent of the patients experienced improvement of their deficits immediately after the surgery or had a stable clinical status whereas 20% had neurological deterioration, however, all of them improved after 30 days. CONCLUSION: AC associated with "next-door" iMRI is a complex procedure, but if performed using a meticulous technique, it may improve the overall tumor resection and safety of the patients.

Compressão do nervo ulnar na região do cotovelo ­ síndrome do túnel cubital: revisão da literatura / Compression of the Ulnar Nerve in the Elbow Region - Cubital Tunnel Syndrome: Review of the Literature

A síndrome do túnel cubital é responsável pela neuropatia do nervo ulnar, sendo superada em frequência apenas pela síndrome do túnel do carpo. O nervo ulnar apresenta anatomia complexa podendo sofrer compressão em distintos pontos ao longo de seu trajeto, por isso o entendimento das nuances clínicas e da anatomia pormenorizada assim como da técnica cirúrgica meticulosa torna-se essencial no tratamento desta patologia.

The cubital tunnel syndrome is responsible for the ulnar nerve neuropathy, this condition is surpassed in frequency only by carpal tunnel syndrome. The ulnar nerve has complex anatomy andmay suffer compression at different points along its path, so understanding the clinical nuances and detailed anatomy as well asmeticulous surgical technique becomes essential in the treatment of this pathology.

Lesão granulomatosa intracraniana mimetizando meningioma: Relato de um caso da doença de Erdheim-Chester / Granulomatous lesion mimicking intracranial meningioma: Erdheim-Chester Disease case report

Erdheim-Chester disease (ECD) is a rare non-Langerhans cells histiocytosis witch affects multiple organs with variable clinicalpresentation. It has a challenging diagnosis most often done after extesnsive investigation. There are no pathognomonicradiological or histological patterns, that is why the diagnosis is based on clinical suspect when all findings areput together andthe immunohistochemistry differentiates from others histiocytosis.The central nervous system involvement is even more rare and the presentation may vary from nodular lesion, white matterinfiltration, to expansive mass effect tumors that may need surgical intervention.In this article we present a case report of ECD and discuss diagnostic and terapeutic options.

Is there a right time for surgery in paraplegic patients secondary to non traumatic spinal cord compression? / Há um período exato para cirurgia em pacientes com paraplegia secundária à compressão medular não traumática?

Paraplegia is a well-defined state of complete motor deficit in lower limbs, regardless of sensory involvement. The cause of paraplegia usually guides treatment, however, some controversies remain about the time and benefits for spinal cord decompression in nontraumatic paraplegic patients, especially after 48 hours of the onset of paraplegia. The objective of this study was to evaluate the benefits of spinal cord decompression in such patients. We describe three patients with paraplegia secondary to non-traumatic spinal cord compression without sensory deficits, and who were surgically treated after more than 48 hours of the onset of symptoms. All patients, even those with paraplegia during more than 48 hours, had benefits from spinal cord decompression like recovery of gait ability. The duration of paraplegia, which influences prognosis, is not a contra-indication for surgery. The preservation of sensitivity in this group of patients should be considered as a positive prognostic factor when surgery is taken into account.

A paraplegia é uma condição de déficit motor completo dos membros inferiores, independente do envolvimento de sensibilidade. A causa da paraplegia normalmente guia o tratamento, porém existem controversas sobre o momento e o benefício da descompressão medular em pacientes paraplégicos, principalmente após 48 horas do início dessa condição. O objetivo deste trabalho foi avaliar o beneficio da descompressão medular nesses pacientes. Foram descritos três pacientes com paraplegia secundária à compressão medular não traumática, sem déficits sensoriais e que foram submetidos à cirurgia após 48 horas do início dessa condição. Todos os pacientes, inclusive aqueles com mais de 48 horas do início dos sintomas, apresentaram melhora neurológica com a descompressão medular, como a recuperação da habilidade de marcha. A duração da paraplegia, que influencia no prognóstico, não é uma contraindicação absoluta para o procedimento cirúrgico. A preservação de sensibilidade desse grupo de pacientes deve ser considerada como fator prognóstico positivo quando a cirurgia for levada em conta.

Is there a right time for surgery in paraplegic patients secondary to non traumatic spinal cord compression?

Paraplegia is a well-defined state of complete motor deficit in lower limbs, regardless of sensory involvement. The cause of paraplegia usually guides treatment, however, some controversies remain about the time and benefits for spinal cord decompression in nontraumatic paraplegic patients, especially after 48 hours of the onset of paraplegia. The objective of this study was to evaluate the benefits of spinal cord decompression in such patients. We describe three patients with paraplegia secondary to non-traumatic spinal cord compression without sensory deficits, and who were surgically treated after more than 48 hours of the onset of symptoms. All patients, even those with paraplegia during more than 48 hours, had benefits from spinal cord decompression like recovery of gait ability. The duration of paraplegia, which influences prognosis, is not a contra-indication for surgery. The preservation of sensitivity in this group of patients should be considered as a positive prognostic factor when surgery is taken into account.

Diffuse meningeal tuberculosis: case report / Tuberculose meníngea difusa: relato de caso

A infecção do sistema nervoso central pela Mycobacterium tuberculosis (MT), apesar de ser incomum em pacientes imunocompetentes, traz um desafio diagnóstico na medicina moderna. O envolvimento subdural da MT pode simular doenças neoplásicas ou inflamatórias, trazendo influência direta na terapêutica. Os autores apresentam nesse trabalho uma paciente de meia idade com envolvimento atípico do espaço subdural pela MT. Uma biópsia aberta foi realizada e o tratamento padrão para MT do sistema nervoso central foram realizados, com significativa melhora da função motora. Nos países em que a MT tem grande prevalência e incidência, a existência de lesão intracraniana atípica deve sempre ser suspeitada como envolvimento do sistema nervoso central pela MT.

central nervous system infection by Mycobacteriumtuberculosis (MT), uncommonly seen in immunocompetentpatients, brings a diagnose challenge in the modern medicine.Subdural space involvement of MT may simulate neoplasticor inflammatory diseases, bringing a direct influence in thetherapeutics. We present a case report of a tetraparetic middleagewoman with an atypical subdural space involvementby MT. Biopsy was done and the standard treatment forcentral nervous system MT was instituted, with a significantimprovement in the motor function. In countries where MTinfection has high prevalence and incidence, an atypicalintracranial mass should be always suspected for centralnervous system involvement by MT.

Coloração sem corantes artificiais em endoscopia digestiva: utilização do espectro eletromagnético da luz / Coloring without artificial dyes in digestive endoscopy: using the eletromagnetic espectrum of light

Apresenta-se aqui um método simples, aparentemente eficaz e sem custo adicional algum, além de não haver prejuízo de nenhuma espécie aos pacientes, submetidos à endoscopia digestiva seja alta ou baixa, que se mostra adequado para se obter imagens endoscópicas com maiores definições e qualidades sem o uso de qualquer tipo de corante artificial ou técnicas de rnaqnificação de imagens. Alguns conceitos simples de ótica, luz e ondas eletromagnéticas serão utilizadas para explicar o modo de obtenção das imagens aqui mostradas, que são apenas uma pequena amostra das que temos em gravações em DVDs dos exames rotineiros realizados em nosso Serviço de Endoscopia. Assim, achamos que este simples método poderá ser útil na rotina de procedimentos endoscópicos dos mais diversos Serviços de Endoscopia. Com a aplicação desta técnica, observamos que tecidos sadios refletem o mesmo feixe de luz branca emitida pelo endoscópio de modo diferente que os tecidos acometidos por patologias sejam inflamatórias, displásicas ou neoplásicas. Mais estudos deveriam ser realizados em Centros Avançados de Endoscopia onde há um grande potencial de pesquisadores científicos de envergadura. Além do mais, acreditamos que o estudo do comportamento eletromagnético dos tecidos vivos e sua emissão de biofótons deveria merecer uma atenção maior pela comunidade científica brasileira...

Obstrução duodenal por corpo estranho (compressa cirúrgica) retirado por via endoscópica / Duodenal obstruction by foreign body (surgical pack) removed by endoscopy

As obstruções duodenais têm variadas causas, dentre as quais se destacam a ulcera péptica em atividade ou estenose cicatricial destas, divertículos e outras. As obstruções por corpo estranho ocorrem na maior parte das vezes devido a ingestão acidental ou mesmo intencional, porém, neste caso, a obstrução se fez de maneira incomum, não tendo sido encontrado relato de caso semelhante na literatura especializada. Essa obstrução foi provocada por uma compressa cirúrgica deixada inadvertidamente durante uma colecistectomia convencional, em outro serviço, que posteriormente veio a perfurar a parede duodenal anterior e se insinuar por esse orifício, criando a obstrução completa do bulbo duodenal. Sua resolução se fez através da endoscopia, não tendo havido complicação tanto imediata quanto tardia, com recuperação completa da paciente em pouco tempo