Clinical use of a neuronavigation system in hemangioblastoma resection of posterior cranial fossa

Application of Virtual Navigation with Multimodality Image Fusion in Foramen Ovale Cannulation

Objective

Idiopathic trigeminal neuralgia (ITN) can be effectively treated with radiofrequency thermocoagulation. However, this procedure requires cannulation of the foramen ovale, and conventional cannulation methods are associated with high failure rates. Multimodality imaging can improve the accuracy of cannulation because each imaging method can compensate for the drawbacks of the other. We aim to determine the feasibility and accuracy of percutaneous foramen ovale cannulation under the guidance of virtual navigation with multimodality image fusion in a self-designed anatomical model of human cadaveric heads.

Design

Five cadaveric head specimens were investigated in this study. Spiral computed tomography (CT) scanning clearly displayed the foramen ovale in all five specimens (10 foramina), which could not be visualized using two-dimensional ultrasound alone. The ultrasound and spiral CT images were fused, and percutaneous cannulation of the foramen ovale was performed under virtual navigation. After this, spiral CT scanning was immediately repeated to confirm the accuracy of the cannulation.

Results

Postprocedural spiral CT confirmed that the ultrasound and CT images had been successfully fused for all 10 foramina, which were accurately and successfully cannulated. The success rates of both image fusion and cannulation were 100%.

Conclusions

Virtual navigation with multimodality image fusion can substantially facilitate foramen ovale cannulation and is worthy of clinical application.

Hemangioblastomas of the Posterior Cranial Fossa in Adults: Demographics, Clinical, Morphologic, Pathologic, Surgical Features, and Outcomes. A Systematic Review

BACKGROUND

Posterior cranial fossa (PCF) hemangioblastomas are benign, highly vascularized, and well-differentiated tumors with well-described histopathologic features. Although relatively rare, this tumor is the most prevalent primary tumor of the cerebellum in adults.

OBJECTIVE

Because the demographics of patients with such a tumor (as well as the clinical, morphologic, pathologic, surgical features, and outcomes) are not fully understood, we systematized characteristic patient and tumor features.

METHODS

We undertook a systematic review of the English-language literature in PubMed for PCF hemangioblastomas in adults published in the past 31 years. We analyzed geographic distribution and year of publication of articles; demographic data of patients; presenting symptoms and clinical signs; tumor location and morphology; histopathologic features, extent of tumor resection, perioperative blood loss, and postoperative complications; length of hospital stay; and outcomes.

RESULTS

We reviewed 207 articles describing 1759 infratentorial hemangioblastomas in a cohort of 1515 adult patients. We found female predominance in patients with Von Hippel-Lindau disease (VHLD) compared with male predominance in the general patient group. Symptoms of intracranial hypertension were more common in the VHLD group compared with the general group of patients. The cerebellar location was more common in the VHLD group and solid (parenchymatous) tumor was the most common type. Most patients underwent total resection but rate of resection did not differ between the general and VHLD groups. Most patients had a favorable outcome.

CONCLUSIONS

The literature of adult PCF hemangioblastomas is limited and general surgical experience with such tumors is scarce because of their rarity. Rates of postoperative complications and mortality remain higher than expected. However, prognosis and surgical outcomes are generally favorable. Nevertheless, surgery of adult PCF hemangioblastomas is a demanding and challenging task.

Bony surface registration of navigation system in the lateral or prone position: technical note

BACKGROUND

Navigation systems have become essential tools in neurosurgery. Precise registration is indispensable for the accuracy of navigation. The rapid and precise registration by surface matching on the facial skin is possible using the landmarks of the face in the supine position. On the other hand, incomplete registration often occurs in the lateral or prone position due to the direction of the face and displacement of the skin by headpins and obscuring of the skin by the bispectral index monitor and many electrodes on the forehead as well as the eye patch. Surface matching on the occipital scalp is not suitable for registration because the shape of the occipital scalp is flat and it is compressed in the supine position when obtaining preoperative neuroimaging. To overcome this problem, the authors have developed a new method of registration designated as "bony surface registration" in which surface matching is achieved using the bony surface of the skull after exposure.

METHODS

Between June and December 2014, this technique was used in 23 patients and its effectiveness was examined.

RESULTS

Registration time was markedly shortened and useful navigation was achieved due to accurate registration in all patients.

CONCLUSIONS

This is the first report of a registration methodology for a navigation system in the lateral or prone position. This bony surface registration method is useful for navigation system image-guided surgery in the lateral or prone position.

Electromagnetic navigation-guided surgery in the semi-sitting position for posterior fossa tumours: a safety and feasibility study

BACKGROUND

Electromagnetic (EM)-guided neuronavigation is an innovative technique and a viable alternative to opto-electric navigation. We have performed a safety and feasibility study using EM-guided neuronavigation for posterior fossa surgery in the semi-sitting position in a selected subset of patients.

METHODS

Out of 284 patients with posterior fossa tumours operated upon over a period of 40 months, a subset of 15 patients was thought to possibly benefit from EM navigational guidance and was included in this study. There were six children and nine adults (aged between 8 and 84 years; mean age, 34.6 years) with different neoplasms in the brainstem or close to the midline. All patients had contrast-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) of the head preoperatively. EM-guided navigation was used to identify and preserve the venous sinuses during craniotomy and to determine the trajectory to the lesion using various approaches. Neuronavigation accuracy was repeatedly checked for deviations measured in millimetres on screen shots during surgery before and after dural opening in the coronal (z = vertical), axial (x = mediolateral) and sagittal (y = anteroposterior) plane.

RESULTS

Referencing of the patient in the supine position was fast and easy. There was no loss of navigation accuracy after repositioning of the patient in the semi-sitting position (mean, 2.5 mm ± 0.92 mm). Identification of the pathological structure using EM navigation was achieved in all instances. Optimal angulation of the neck was selected individually to permit a comfortable position for the surgeon with full access to the lesion avoiding over-flexion. Deviation of accuracy at the surface of the target lesion ranged between 2.5 and 5.8 mm (mean, 3.9 mm ± 1.1 mm).

CONCLUSIONS

EM-guided neuronavigation in the semi-sitting position was safe and technically feasible. It enabled fast and accurate referencing without loss of navigation accuracy despite repositioning of the patient. In contrast to conventional opto-electric neuronavigation there were no line of sight problems.

Experimental study on restricting the robotic end-effector inside a lesion for safe telesurgery

INTRODUCTION

Using an endoscopic telesurgical robot system (ETSRS), the authors propose a strategy for improving the safety of telesurgery by restricting the movement of an end-effector within a lesion. The strategy is validated by phantom model experiments.

MATERIAL AND METHODS

The method focused on generation of force feedback and restriction of robotic end-effector movement of ETSRS based on a virtual wall. Collision detection and case classification procedures were used to determine whether the generation of force feedback or restricting the end-effector's movement was continued. The method was implemented in ETSRS and tested using a brain and tofu phantom.

RESULTS

Force feedback was well generated proportional to a linear combination of the insertion depth and the velocity of the end-effector of the ETSRS from the surface of the predefined virtual wall. The movement of the end-effector was well limited inside the virtual wall by the method. The virtual wall update was sufficiently fast to check the current surgical situation. The control rate of the entire system was >30 fps so that the method showed acceptable performance in phantom experiments.

CONCLUSION

The results show that the strategy allows for well controlled robotic end-effectors inside a predefined virtual wall by the robot itself and an operator through the signal and force feedback.

Assessment of the OsteoMark-Navigation System for Oral and Maxillofacial Surgery

PURPOSE

To assess the accuracy of a novel navigation system for maxillofacial surgery using human cadavers and a live minipig model.

MATERIALS AND METHODS

We tested an electromagnetic tracking system (OsteoMark-Navigation) that uses simple sensors to determine the position and orientation of a hand-held pencil-like marking device. The device can translate 3-dimensional computed tomographic data intraoperatively to allow the surgeon to localize and draw a proposed osteotomy or the resection margins of a tumor on bone. The accuracy of the OsteoMark-Navigation system in locating and marking osteotomies and screw positions in human cadaver heads was assessed. In group 1 (n = 3, 6 sides), OsteoMark-Navigation marked osteotomies and screw positions were compared to virtual treatment plans. In group 2 (n = 3, 6 sides), marked osteotomies and screw positions for distraction osteogenesis devices were compared with those performed using fabricated guide stents. Three metrics were used to document the precision and accuracy. In group 3 (n = 1), the system was tested in a standard operating room environment.

RESULTS

For group 1, the mean error between the points was 0.7 mm (horizontal) and 1.7 mm (vertical). Compared with the posterior and inferior mandibular border, the mean error was 1.2 and 1.7 mm, respectively. For group 2, the mean discrepancy between the points marked using the OsteoMark-Navigation system and the surgical guides was 1.9 mm (range 0 to 4.1). The system maintained accuracy on a live minipig in a standard operating room environment.

CONCLUSION

Based on this research OsteoMark-Navigation is a potentially powerful tool for clinical use in maxillofacial surgery. It has accuracy and precision comparable to that of existing clinical applications.

Construction and verification of a safety region for brain tumor removal with a telesurgical robot system

BACKGROUND

The authors propose and verify a method for the construction of a safety region for minimally invasive brain tumor removal. The safety region is constructed to avoid damaging normal tissues through the movement of a robotic instrument during brain tumor surgery using a telesurgical robotic system and a small port.

MATERIAL AND METHODS

3 D boundaries of a tumor and a port were generated as a critical wall to avoid invading normal tissues through an image processing algorithm with consideration of a safe margin. Then, fast collision detection between the boundary and the robotic instrument was continuously performed to monitor the movement of the robotic instrument.

RESULTS

An experiment was conducted using the prototype of a telesurgical robot system and a hemispherical phantom. A 3 D boundary was generated from the CT images of the phantom with a safe margin of 2.76 mm. The robotic instrument did not penetrate the boundary.

CONCLUSION

The experimental result shows that our method can contribute toward safe brain tumor removal with robotic surgery.

Relative anterior safe area for invasive procedures in the human brain: diffusion tensor tractography

OBJECTIVE

Many interventions, including surgery, procedures of shunt operation, or radiotherapy could result in neural injury of the brain. However, research to prevent or minimize injury of neural tracts has been overlooked.

MATERIAL AND METHODS

We recruited 41 healthy subjects. Diffusion tensor images were acquired and five neural tracts were reconstructed (corticospinal tract, corticoreticular pathway, arcuate fasciculus, cingulum, and superior longitudinal fasciculus). We defined the safe area, which is an area free from any trajectory of five neural tracts: the medial boundary - the most lateral point free from any trajectory of five neural tracts, the posterior boundary - the most anterior point free from any trajectory of five neural tracts.

RESULTS

Medial boundaries of the safe area in the cortex, centrum semiovale, corona radiata, and internal capsule were located at an average of 0 mm, 12.28 mm, 12.43 mm, and 10.34 mm laterally from the midline, respectively, and the posterior boundaries were located at an average of 1.30 mm, 4.26 mm, 7.05 mm, and 5.74 mm from the ACL, respectively. In addition, we found that the common safe areas for all four axial levels were located at 13.44 mm (medial boundary) and 9.35 mm (posterior boundary).

CONCLUSION

We identified a relatively safe area for the performance of invasive procedures in the anterior portion of the human brain.