The Extreme Lateral Approach to the Craniovertebral Junction: An Anatomical Study.

BACKGROUND: The extreme lateral approach is a direct lateral approach which allows a good control of the entire length of the vertebral artery (VA), the jugular foramen, the lowest cranial nerves, and the jugular-sigmoid complex. Herein we try to exploit the variants of the approach and we identify indications, advantages, and disadvantages. METHODS: All phases of the study were conducted at the Institute of Public Health Section of Legal Medicine and Insurance of the University. We performed the extreme lateral approach in four subjects, who died between 24 and 48 h before in non-traumatic circumstances (three men and one woman). RESULTS: The great auricular nerve, the spinal accessory, the branches of the first ventral spinal nerves, the jugular vein, and the vertebral artery were identified in all the cadavers. In all cases the right VA exited from the transverse foramen of C1. The site of SCM piercing the accessory nerve was at a distance from the tip of the mastoid between 3 and 4 cm (3.3 in one case, 3.4 in 2 cases, and 3.7 in one case). No vessels and nerves have been damaged after being identified and isolated. CONCLUSIONS: Extradural lesions at the ventro-lateral aspect of the CVJ may require an extreme lateral approach, a procedure more aggressive comparing with far lateral approach, which represents a reasonable option for large anterior and anterolateral lesions when greater exposure is required.

Extreme Lateral Approach to the Craniovertebral Junction: An Update.

INTRODUCTION: The term 'extreme lateral approach' (ELA) was first introduced by Sen and Sekhar relatively recently (in 1990). Its definition varies and remains controversial, but it generally entails more aggressive bony removal than the far lateral approach (FLA). GOAL: In this paper we review the relevant literature and weigh up the advantages and disadvantages of this approach. We propose methods to manage the complications resulting from the more invasive character of the ELA. Some modern trends regarding how to definitely distinguish the ELA from the FLA are also presented. METHODS: Using the PubMed database, literature was collected on the relevant topics and subsequently reviewed. All up-to-date tips and tricks were carefully gathered, and current morbidity and mortality rates were obtained, as well as further perspectives. RESULTS AND CONCLUSION: The morbidity associated with the ELA remains higher than that associated with the FLA, but the mortality nowadays is comparable. The ELA undoubtedly is a challenging procedure requiring deep insight into the relevant anatomy and its normal variants.

Why the Craniovertebral Junction?

The craniovertebral junction (CVJ) has unique anatomical bone and neurovascular structure architecture. It not only separates the skull base from the subaxial cervical spine but also provides a special cranial flexion, extension and axial rotation pattern. Stability is provided by a complex combination of osseous and ligamentous supports, which allow a large degree of motion. Perfect knowledge of CVJ anatomy and physiology allows us to better understand instrumentation procedures of the occiput, atlas and axis, and the specific diseases that affect the region. Therefore, a review of the vascular, ligamentous and bony anatomy of the region, in relation to all possible surgical approaches to this anatomically unique segment of the cervical spine, appears to be absolutely mandatory in order to preview and to overcome possible anatomy-related complications of CVJ surgery; moreover, knowledge of the basic principles of instrumentation and of the kinematics of the region, since they interact with the anatomy, seems to be strategic in preoperative planning.Historically considered a no man's land, CVJ surgery, or the CVJ specialty, has recently attracted strong consideration as a symbol of challenging surgery as well as selective top-level qualifying surgery.Although many years have passed since the beginning of this pioneering surgery, managing lesions situated in the anterior aspect of the CVJ still remains a challenging neurosurgical problem. Many studies are available in the literature, aiming to examine the microsurgical anatomy of both the anterior and posterior extradural and intradural aspects of the CVJ, as well as the differences in all possible surgical exposures obtained by the 360° approach philosophy. In this paper the author provides a short but quite complete at-a-glance tour of personal experience and publications and the more recent literature available.

Arthroscopic Treatment of Popliteus Tendinitis Using the Accessory Portal.

Introduction: This study aimed to evaluate the effect of arthroscopic treatment of popliteus tendinitis via an auxiliary extreme lateral approach and to investigate the pathogenesis and treatment of popliteus tendinitis. Materials and Methods: From 2016 to 2020, arthroscopic popliteus tendon ablation was performed in 15 patients (15 knees) with popliteus tendinitis via an auxiliary extreme lateral approach. Clinical outcomes were assessed using the Lysholm knee scoring scale, the Tegner score, the International Knee Documentation Committee (IKDC) score and the visual analogue scale (VAS) pain score at the 24-month follow-up after surgery. Results: A total of 15 patients (mean age, 51.1 ± 7.1 years) were included. They had a mean body mass index of 23.8 ± 2.1 kg/m2. The minimum follow-up period was 24 months. Comparing the postoperative state to the preoperative state, the mean postoperative Lysholm score, Tegner score, and IKDC score improved significantly from 70.0 ± 5.0, 3.0 ± 0.9, and 62.3 ± 5.5 to 89.3 ± 4.2, 4.6 ± 0.61, and 80.5 ± 4.4, respectively (p < 0.01). The preoperative VAS score for pain improved from 6.4 ± 0.5 to 0.9 ± 0.4 (p < 0.01). No patients were lost to follow-up. Conclusions: Following arthroscopic-assisted treatment, all the patients with popliteus tendinitis achieved satisfactory clinical outcomes in terms of pain relief and improved function. Level of Evidence: Level IV.

Hypoglossal Nerve Schwannoma With Severe Brainstem Compression: Microsurgical Excision by Extreme Lateral Approach: 2-Dimensional Operative Video.

A 37-yr-old male presented with a history of left-sided tongue atrophy and fasciculations and weakness of upper limbs for 3 mo. Magnetic resonance imaging (MRI) revealed a large, partially cystic tumor with severe compression of the brainstem and spinal cord, with expansion and erosion of the hypoglossal canal. Computed tomography (CT) angiography showed the left vertebral artery to be anteriorly displaced by the tumor. A retrosigmoid craniotomy and craniectomy were performed followed by mastoidectomy with unroofing the posterior aspect of the sigmoid sinus. The foramen magnum was completely unroofed. The hypoglossal canal was exposed with a diamond drill and an ultrasonic bone curette, and a tumor was seen within the expanded canal. C1 lamina was removed partially in the lateral aspect, and the occipital condyle was partially removed. After opening the dura mater, the tumor was found to be stretching the eleventh cranial nerve. The tumor was debulked, and dissected from the cranial nerve fibers. The vertebral artery, anterior spinal artery, and other branches displaced by the tumor were carefully preserved. The tumor was removed from the hypoglossal canal with a curette. The patient recovered well, with the resolution of his upper limb weakness. Patient modified Rankin Scale was 1 at 6-mo follow-up. The postoperative MRI showed a small remnant inside the hypoglossal canal, and it was treated by radiosurgery. This 2-dimensional video demonstrates the technique of complete microsurgical removal of a complex tumor with preservation of cranial nerves and vertebral artery. Informed consent was obtained from the patient prior to the surgery, which included videotaping of the procedure and its distribution for educational purposes. Also, all relevant patient identifiers have been removed from the video and accompanying radiology slides.

Comparative Analysis of the Subtonsillar, Far-Lateral, Extreme-Lateral, and Endoscopic Far-Medial Approaches to the Lower Clivus: An Anatomical Cadaver Study.

BACKGROUND: The lower clivus (LC) is one of the most difficult areas to access in neurosurgery. Several microsurgical approaches to the LC have been reported, including the subtonsillar, far-lateral (FL), extreme-lateral (EL), and endoscopic far-medial (Endo-FM). However, no consensus has been reached regarding the optimal approach. We aimed to quantify and compare the surgical exposure and freedom (angle of attack) for various targets at the LC using these 4 surgical approaches. METHODS: The subtonsillar, FL, EL, and Endo-FM approaches were performed on 5 cadaveric specimens (total 10 sides). Surgical exposure and freedom were measured using the neuronavigation system. RESULTS: At the LC, the Endo-FM approach provided the greatest area of exposure (459.3 ± 82.2 mm2). For surgical freedom, the EL approach provided the greatest angle of attack at the jugular foramen (98.1° ± 9.2°) and hypoglossal canal (128.8° ± 26.1°). The Endo-FM was the only approach that provided access to the midline of the LC in all specimens. However, the surgical freedom at the midline (20.9° ± 2.4° at the level of the jugular foramen; 24.2° ± 2.9° at the level of hypoglossal canal) was limited by its deep surgical corridor (104.3 ± 11.2 mm) compared with the EL and FL approaches. CONCLUSION: The Endo-FM approach provided the greatest surgical freedom at the ventral aspect but the least freedom at the lateral aspect. The EL approach provided maximal values for most parameters among the open approaches; however, the craniotomy with the EL approach was the most complicated. Our quantitative results could guide neurosurgeons in preoperative planning for LC lesions, including awareness of the maximum exposure limits and the advantages and disadvantages of each surgical approach.

Arthroscopic removal of loose bodies using the accessory portals in the difficult locations of the knee: a case series and technical note.

BACKGROUND: It is often technically demanding to find and remove loose bodies in several difficult locations like the popliteus hiatus and posterior compartment arthroscopically. We aim to present the technical aspects of establishing some special accessory portals to achieve arthroscopic removal of the loose bodies in these locations. METHODS: From September 2010 to July 2017, 76 patients underwent removal of loose bodies in the popliteus hiatus and posterior compartment arthroscopically using some special accessory portal techniques. An auxiliary extreme lateral approach was established to remove loose bodies in the popliteus hiatus; a double-posteromedial portal was applied to handle loose body removal in the posteromedial compartment, and the posterior trans-septal portal was needed for loose body removal in the posterolateral compartment. Functional outcomes were evaluated using Lysholm score, Tegner score, and International Knee Documentation Committee (IKDC) score, respectively. RESULTS: Seventy-six patients (24 males and 52 females, average age 54.9 ± 11.4) finished the follow-up visit at 3 weeks after surgery. There was no statistically significant difference among the three groups in demographics. All the patients were performed following the special technique. According to a comparison of knee joint scores before and after surgery, all the patients obtained good prognosis using some special accessory portals in loose body removal. CONCLUSIONS: With the help of the above accessory portals under endoscopic visualization, loose bodies in the popliteus hiatus and posterior compartment of the knee can be safely and effectively removed.

Endoscope-Assisted Microsurgical Approach to the Posterior and Posterolateral Incisural Space.

OBJECTIVE: Despite recent technological advances, direct approaches to the posterolateral incisural space remain surgical challenges. The choice of the operative route depends on the exact location and extent of the target lesion as well as individual preferences. The extreme lateral infratentorial supracerebellar approach to treat pathologies located in the ambient cistern and posterior incisural space is a technically feasible route in selected cases. In this cadaveric study, we demonstrate the benefits of endoscope-assisted microsurgical maneuvers using the extreme lateral supracerebellar infratentorial approach. METHODS: An endoscope-assisted infratentorial supracerebellar approach was performed in six formalin-fixed cadaveric heads using standard microneurosurgical methods. Dissections were performed in a stepwise fashion, comparing the exposure afforded by the microsurgical route alone to the endoscope-assisted route, using 0- and 30-degree angled lenses. Relationships among the target and the surroundings neurovascular structures were described. RESULTS: Endoscope-assisted maneuvers for the extreme lateral supracerebellar approach provide an improved operative view and have the potential to reduce parenchymal trauma and neurovascular injuries. The endoscopic techniques bring the surgeon to the anatomy, enhancing illumination and surgical visualization. CONCLUSIONS: Direct visualization of the posterior and posterolateral incisural space avoids retraction of the occipital lobe and damage to the deep venous complex. The extreme lateral infratentorial supracerebellar corridor is effective for approaching the posterolateral mesencephalic junction and the posterior incisural space in selected cases. Endoscope-assisted microsurgery can improve visualization and minimize parenchymal retraction, which should enhance surgical control.

Clinical Analysis of One-Stage Debridement,Bone Grafting and Internal Fixation for the Treatment of Single-Segmental Lumbar Spinal Tuberculosis with Extreme Lateral Approach / 中山大学学报(医学科学版)

[Objective]To analyze the feasibility and clinical efficacy of one-stage debridement,bone grafting and in-ternal fixation for the treatment of single-segmental lumbar spinal tuberculosis with extreme lateral approach.[Methods]Thirteen patients of single-segmental lumbar spinal tuberculosis that received the surgeries from April 2013 to August 2016 were included.The operation duration and the amount of intraoperative blood loss were recorded.The VAS and ODI of the back pain,lumbar kyphosis angle,segment height restoration,and vertebral fusion rate were used to analyze the clinical efficacy.[Results]Thirteen patients were successfully followed up for 13-32 months(mean,20.3 months);the operation duration was 160-280 min(average,214±96)min;the amount of intraoperative blood loss was 150-350 mL, average(average,263±63)mL. At the final follow-up,ESR and CRP were normal and lower back pain(VAS)and Oswestry disability index(ODI)were significantly reduced(7.2±1.6 vs 2.5±1.2 and 63.3±5.4 vs 31.9±3.7,respectively)compared to preoperative values;there were no significant difference in the lumbar kyphosis angle,segment height resto-ration between preoperation(segmental lordosis,7.1°±4.7°;segmental height,64.8 mm±9.3 mm)and the values at final follow-ups(segmental lordosis,5.2°±3.5°;segmental height,69.4 mm±10.5 mm;P>0.05). All cases acquired good lumbar interbody fusion with no internal fixation failure or recurrence of tuberculosis.[Conclusions]Under systemic and routine antituberculosis chemotherapy,one-stage extreme lateral approach debridement,bone graft and internal fixation is effective and feasible for single-segmental lumbar spinal tuberculosis.

Surgical treatment of ventral and ventrolateral intradural extramedullary tumors of craniovertebral and upper cervical localization.

BACKGROUND: Surgical treatment of extramedullary craniovertebral and upper cervical tumors differs essentially, depending on the peculiarities of their localization. MATERIALS AND METHODS: In the Spinal Department of the Institute of Neurosurgery during the period from 2000 to 2010, 96 patients with ventral and ventrolateral intradural extramedullary craniovertebral tumors and tumors of upper cervical localization were examined and operated. RESULTS: The patients were distributed as follows. Tumors of the craniovertebral localization: These are neoplasms spreading in rostral direction up to the boundary of the lower third of the clivus and in caudal direction up to the upper edge body of the axis (C0-C1) - 12 patients; tumors at the C1-C2 level: 28 patients; and tumors at the C1-C2-C3 level: 56 patients. The tumors were divided into ventral (60) and ventrolateral (36). CONCLUSION: Therefore, the adequate choice of a surgical approach first depends on the localization of the tumor, its size and the extent to which it has spread. In most cases of extramedullary ventrolateral tumors of craniovertebral and upper cervical localization, far lateral and posterolateral approaches are the most optimum and the least traumatic. The extreme lateral approach is advisable in cases of big size ventral craniovertebral tumors.

Surgical treatment of ventral and ventrolateral intradural extramedullary tumors of craniovertebral and upper-cervical localization.

INTRODUCTION: Surgical treatment of extramedullary craniovertebral and upper-cervical tumors differs essentially, depending on the peculiarities of their localization. MATERIALS AND METHODS: In the Spinal department of the Institute of Neurosurgery during the period from 2000 to 2010 years, 96 patients with ventral and ventrolateral intradural extramedullary craniovertebral tumors and tumors of upper-cervical localization were examined and operated. The patients were distributed as follows: tumors of the craniovertebral localization - neoplasms spreading in rostral direction up to the boundary of the lower third of the clivus, and in caudal direction up to the upper edge body of the axis (C0 - C1): 12patients; tumors at the C1 - C2 level: 28 patients and at 1 - C2 - C3 level: 56 patients. The tumors were also divided as: ventral - 60 patients and ventrolateral - 36 patients. CONCLUSION: Therefore, the adequate choice of a surgical approach firstly depends on the localization of the tumor, its size and the extent to which it has spread. Far-lateral and posterolateral approaches in most cases are the most optimum and the least traumatic in cases of extramedullary ventrolateral tumors of craniovertebral and upper cervical localization. The extreme lateral approach is advisable in cases of large sized ventral craniovertebral tumors.

Approaches to anterior and anterolateral foramen magnum lesions: A critical review.

Foramen magnum (FM) lesions represent some of the most complex cases for the modern neurosurgeon because of their location near vital brainstem structures, the vertebral arteries, and lower cranial nerves. In particular, anterior or anterolaterally located FM tumors have traditionally been most difficult to resect with high morbidity and mortality resulting from approaches through the posterior midline or transorally. For many neurosurgeons, the far lateral, extreme lateral approach, and more recently, endoscopic endonasal approaches have become the preferred modern methods for the resection of anterior or anterolateral FM tumors. In this review, we examine both operative and non-operative approaches to FM tumors, including surgical anatomy, surgical technique, and indications for operative intervention in these complex cases. In addition, we compared outcomes from prior series.

Tratamiento quirúrgico de aneurisma de la arteria cerebelosa postero inferior gigante embolizado / Surgical treatment of embolized giant posteroanterior cerebellar artery aneurysm

Objetivo: descripción de la resolución quirúrgica de un aneurisma complejo, gigante de circuito posterior (arteria cerebelosa posteroinferior), embolizado previamente, y la evolución postoperatoria. Descripción: Paciente de 48 años de edad con antecedentes de hidrocefalia obstructiva, e hipertensión de fosa posterior, la cual fue tratada por vía endovascular hace 4 años, con colocación de derivación ventricular, y craniectomía descompresiva de fosa posterior, con evolución progresiva de déficit de pares craneales bajos, y síndrome de hipertensión endocraneana. Intervención: Se realizó abordaje extremo lateral con drilado parcial del cóndilo occipital, control proximal de la arteria vertebral, y reconstrucción de la pared aneurismática del sector arteria vertebral- arteria cerebelosa posteroinferior (PICA), mediante microcirugía, con posterior apertura del saco dural y remoción de coils y trombosis intraaneurismática, removiendo el efecto de masa aneurismático. Conclusión: El tratamiento microquirúrgico con la técnica de la reconstrucción parietal del aneurisma y el control proximal del mismo, en conjunto con abordajes de base de cráneo permiten el definitivo y adecuado tratamiento para los aneurismas gigantes de la pica.

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.

Meningiomas do forâmen magno / Foramen magnum meningiomas

Contexto: Os meningiomas do forâmen magno são patologias raras e representam um dos mais desafiantes tumores do sistema nervoso central em relação ao seu tratamento cirúrgico. Sua frequência varia na literatura em torno de 3% dos meningiomas. Podem ser classificados como ventrais, ventrolaterais e dorsais. Tal classificação é importante, pois define a abordagem cirúrgica a ser utilizada. Objetivo: Revisão dos aspectos clínicos e terapêuticos desse raro e intrigante tumor. Método: Pesquisa eletrônica no PubMed (www.pubmed.com) utilizando as seguintes palavras-chave: meningioma do forâmen magno e acesso extremo lateral. Foram revisados dados de trabalhos do período de 1987 a 2008. Também foi realizada pesquisa das publicações mais citadas em relação ao tema. Artigos com dados clínicos incompletos não foram analisados. Resultados: Como todos os meningiomas, são mais frequentes no sexo feminino. Possuem uma apresentação clínica variável. O diagnóstico precoce é mandatório a fim de se atingir os melhores resultados terapêuticos. O tratamento de eleição, definido pela maioria dos autores, é o cirúrgico, embora a radiocirurgia estereotáxica esteja despontando como uma das possibilidades terapêuticas. A maioria das séries publicadas relata uma taxa de ressecção total em torno de 70% dos casos. Conclusões: A melhor opção terapêutica, até o presente momento, é a remoção cirúrgica do tumor. A abordagem ideal ainda não está estabelecida como um consenso, embora esteja se direcionando para o acesso extremo lateral e suas variantes segundo a maioria dos autores. A embolização pré-operatória tem o seu papel definido e deve ser utilizada sempre que possível. A radiocirurgia estereotáxica pode ser uma opção terapêutica para um grupo seleto de pacientes. O diagnóstico precoce continua sendo a melhor arma de todo esse arsenal para que os pacientes desfrutem de um bom resultado terapêutico e evoluam com um prognóstico favorável. Em virtude da complexidade de sua localização anatômica, é necessário o amplo conhecimento da anatomia dos acessos de base de crânio, em especial o acesso extremo lateral e suas variantes.

Context: Foramen magnum meningiomas are rare diseases and represent one of the most challenging tumors of the central nervous system for its surgical treatment. Its frequency varies in the literature corresponding to about 3% of all meningiomas. They are classified as ventral, ventrolateral and dorsal. This classification is important because it defines the surgical approach to be used. Objective: Literature review of clinical and therapeutic aspects of this rare and puzzling tumor. Method: An electronic search in PubMed (www.pubmed.com) using the following keywords: meningioma of the foramen magnum and extreme lateral access. We reviewed data from studies published during the period of 1987 to 2008. We also carried out research into the publications cited in the articles. Articles with incomplete clinical data were not analyzed. Results: Like all meningiomas they are more common in women. They have a variable clinical presentation. Early diagnosis is mandatory in order to achieve the best therapeutic results. The treatment of choice, as defined by most authors, is surgery, while stereotactic radiosurgery is emerging as one of the therapeutic possibilities. Most published series report a total resection rate of around 70%. Conclusions: The best therapeutic option, so far, is the surgical removal of the tumor. The ideal approach is not yet established as a consensus, although it is moving toward the extreme lateral access and its variants according to most authors. The preoperative embolization has its defined role and should be used whenever possible. The stereotactic radiosurgery may be a therapeutic option for a select group of patients. Early diagnosis remains the best factor to achieve a good outcome and a favorable prognosis. Due to the complexity of its anatomical location, one must have extensive knowledge of the anatomy of the skull base, especially that concerning with the extreme lateral access and its variants.