Quantitative evaluation of different far lateral approaches to the cranio-vertebral junction using the microscope and the endoscope: a cadaveric study using a tumor model

Quantitative Anatomical Studies in Neurosurgery: A Systematic and Critical Review of Research Methods

BACKGROUND

The anatomy laboratory can provide the ideal setting for the preclinical phase of neurosurgical research. Our purpose is to comprehensively and critically review the preclinical anatomical quantification methods used in cranial neurosurgery.

METHODS

A systematic review was conducted following the PRISMA guidelines. The PubMed, Ovid MEDLINE, and Ovid EMBASE databases were searched, yielding 1667 papers. A statistical analysis was performed using R.

RESULTS

The included studies were published from 1996 to 2023. The risk of bias assessment indicated high-quality studies. Target exposure was the most studied feature (81.7%), mainly with area quantification (64.9%). The surgical corridor was quantified in 60.9% of studies, more commonly with the quantification of the angle of view (60%). Neuronavigation-based methods benefit from quantifying the surgical pyramid features that define a cranial neurosurgical approach and allowing post-dissection data analyses. Direct measurements might diminish the error that is inherent to navigation methods and are useful to collect a small amount of data.

CONCLUSION

Quantifying neurosurgical approaches in the anatomy laboratory provides an objective assessment of the surgical corridor and target exposure. There is currently limited comparability among quantitative neurosurgical anatomy studies; sharing common research methods will provide comparable data that might also be investigated with artificial intelligence methods.

Classification and microsurgical treatment of foramen magnum meningioma

BACKGROUND

To investigate the classification and microsurgical treatment of foramen magnum meningioma (FMM).

METHODS

We retrospectively analyzed 76 patients with FMM and classified them into two classifications, classification ABS according to the relationship between the FMM and the brainstem and classification SIM according to the relationship between the FMM and the vertebral artery (VA). All patients underwent either the far lateral approach (54 cases) or the suboccipital midline approach (22 cases).

RESULTS

Of the 76 cases, 47 cases were located ahead of the brainstem (A), 16 cases at the back of the brainstem (B), and 13 cases were located laterally to the brainstem (S). There were 15 cases located superior to the VA (S), 49 cases were inferior (I), and 12 cases were mixed type (M). Among 76 cases, 71 cases were resected with Simpson grade 2 (93.42%), 3 with Simpson grade 3 (3.95%), and 2 with Simpson grade 4 (2.63%). We summarized four anatomical triangles: triangles SOT, VOT, JVV, and TVV. The mean postoperative Karnofsky performance score was improved in all patients (p < 0.05). However, several complications occurred, including hoarseness and CSF leak.

CONCLUSION

ABS and SIM classifications are objective indices for choosing the surgical approach and predicting the difficulty of FMMs, and it is of great importance to master the content, position relationship with the tumor, and variable anatomical structures in the four "triangles" for the success of the operation.

Internal Jugular Vein Thrombosis: Etiology, Symptomatology, Diagnosis and Current Treatment

(1) Background: internal jugular vein thrombosis (IJVthr) is a potentially life-threating disease but no comprehensive reviews on etiology, symptomatology, diagnosis and current treatment guidelines are yet available; (2) Methods: we prospectively developed a protocol that defined objectives, search strategy for study identification, criteria for study selection, data extraction, study outcomes, and statistical methodology, according to the PRISMA standard. We performed a computerized search of English-language publications listed in the various electronic databases. We also retrieved relevant reports from other sources, especially by the means of hand search in the Glauco Bassi Library of the University of Ferrara; (3) Results: using the predefined search strategy, we retrieved and screened 1490 titles. Data from randomized control trials were few and limited to the central vein catheterization and to the IJVthr anticoagulation treatment. Systematic reviews were found just for Lemierre syndrome, the risk of pulmonary embolism, and the IJVthr following catheterization. The majority of the information required in our pre-defined objectives comes from perspectives observational studies and case reports. The methodological quality of the included studies was from moderate to good. After title and abstract evaluation, 1251 papers were excluded, leaving 239 manuscripts available. Finally, just 123 studies were eligible for inclusion. We found out the description of 30 different signs, symptoms, and blood biomarkers related to this condition, as well as 24 different reported causes of IJVthr. (4) Conclusions: IJVthr is often an underestimated clinical problem despite being one of the major sources of pulmonary embolism as well as a potential cause of stroke in the case of the upward propagation of the thrombus. More common symptoms are neck pain and headache, whereas swelling, erythema and the palpable cord sign beneath the sternocleidomastoid muscle, frequently associated with fever, are the most reported clinical signs. An ultrasound of the neck, even limited to the simple and rapid assessment of the compression maneuver, is a quick, economic, cost-effective, noninvasive tool. High quality studies are currently lacking.

Comparative analysis of surgical exposure and freedom between the subtonsillar, endoscope-assisted subtonsillar, and far-lateral approaches to the lower clivus: A cadaveric study

The far-lateral (FL)approach is a classic technique for skull base surgeries involving the lower clivus (LC).Recently, a modified suboccipital midline approach known as the subtonsillar (ST) approach, along with the endoscope-assisted subtonsillar (EST) approach, has been described as a minimally invasive technique to treat LC lesions. However, there is no quantitative study on comparing these approaches together for reaching LC. We aimed to compare surgical exposure and freedom provided by ST, EST, and FL approaches for various targets at LC. These approaches were performed on each side of five cadaveric specimens (total 10 sides), and relevant parameters were quantified and compared using a repeated measures ANOVA test. FL approach yielded the greatest surgical area (237.8 ± 56.0 mm²) and exposure, including lengths of glossopharyngeal nerve (16.2 ± 1.9 mm), hypoglossal nerve (11.4 ± 2.4 mm), vertebral artery (23.9 ± 3.3 mm), followed by EST and ST approaches. For surgical freedom, FL approach provided the greatest angle of attack (90.0 ± 14.0° at jugular foramen, 95.1 ± 15.8° at hypoglossal canal, 83.4 ± 31.4° at bifurcation point of posterior inferior cerebellar artery and vertebral artery). Our systematic comparison suggests that EST approach, compared to ST approach, can significantly increase surgical exposure to the medial side of LC, but FL approach still provides the greatest surgical exposure and freedom at LC. Despite the limitations of a cadaveric study, our quantitative data can update the literature on currently available surgical techniques for reaching LC and better inform preoperative planning in this area. Further studies should be performed to evaluate these approaches in clinical practice.

Modified Pure Endoscopic Approach to Pineal Region: Proof of Concept of Efficient and Inexpensive Surgical Model Based on Laboratory Dissections

OBJECTIVE

In recent decades endoscopic techniques have been increasingly used in neurosurgery as they may offer a valuable close-up view of the working area through a minimally invasive surgical corridor. Herein, we present an inexpensive and efficient endoscopic surgical model using a borescope, which was used for a "modified pure endoscopic approach" to the pineal region.

METHODS

A borescope video camera was connected to a 16-inch personal computer monitor. A standard midline suboccipital craniotomy was performed on 2 cadaveric heads in the Concorde position. Then, a "borescopic" supracerebellar infratentorial approach was executed, thus reaching the pineal region, which was exposed through an extensive arachnoid dissection.

RESULTS

Using the previously described model, we were able to provide excellent exposure of the main neurovascular structures of the pineal region, as shown by the intraoperative videos. In 1 specimen we identified an incidental pineal cyst that was meticulously dissected and removed.

CONCLUSIONS

Our proposed "borescopic" surgical model may represent an inexpensive and efficient alternative to conventional endoscopic techniques and could be used for training purposes, as well as even for clinical procedures, after a proper validation, particularly in economically challenging environments.