A 3D endoscopic transtubular transcallosal approach to the third ventricle

Quantitative analysis of exposure and surgical maneuverability of three purely endoscopic keyhole approaches to the floor of the third ventricle

BACKGROUND

The quantitative anatomic analysis of comprehensively endoscopic approaches to the third ventricle is scarce at present. The objective of the study is to quantitatively assess and compare the exposure and microsurgical maneuverability of three absolutely endoscopic keyhole approaches, including interhemispheric transcallosal transchoroidal (TCTC), frontal transforminal transchoroidal (TFTC) and supraorbital subfrontal translamina terminalis (SFTL) approaches.

METHODS

Anatomical dissections and exposure of the important structures of the third ventricle were performed using six formalin-fixed cadaveric human heads (twelve sides) under endoscope. Tubular retractor system was used in the TFTC approach. Quantitative anatomical relationship between the important landmarks were obtained. Moreover, the exposure and surgical operability of three approaches were evaluated through applying the rating scale and accomplishing the quantitative anatomic analysis, area of surgical freedom and angle of attack.

RESULTS

The mediolateral, anteroposterior (AM: between aqueduct and mammillary body; IM: between infundibular recess and mammillary body) and superoinferior distance of TCTC, TFTC and SFTL approaches were 4.0±1.0, 4.2±0.4, 4.1±1.1 mm; 17.3±1.4, 17.6±0.5, 12.8±3.3 mm (AM); 7.7±0.3, 7.8±0.5 mm, not measured (IM); and 5.6±0.3, 7.8±0.8, 7.8±1.5 mm, respectively. Similar to TFTC, the exposed landmarks of TCTC were almost scored a "4" by three neurosurgeons except the infundibular recess scored a "3" according to the rating scale. During the SFTL approach, apart from the roof, the majority of the landmarks were scored a "4" except for the infundibular recess, which was scored a "3." The mean area of surgical freedom of TCTC (0° endoscope: 220±47; 30°: 247±56 mm2) was not significantly different from that of TFTC approach (0° endoscope: 216±49; 30°: 245±53 mm2) under same endoscope, P>0.05. Mean angle of attack of TCTC (0° endoscope: 21±4°; 30°: 26±4°) was significantly larger than that of TFTC approach (0° endoscope: 16±3°; 30°: 19±3°), P<0.05.

CONCLUSIONS

Purely endoscopic TCTC and TFTC approaches offer brilliant exposure of the anterior, middle and posterior third ventricle. TCTC approach may have better surgical maneuverability than TFTC approach. Despite the long working distance, the whole third ventricle are exposed well except for the roof in the SFTL approach, and surgical manipulation can be accomplished smoothly.

A comparison of brain retraction mechanisms using finite element analysis and the effects of regionally heterogeneous material properties

Finite element (FE) simulations of the brain undergoing neurosurgical procedures present us with the great opportunity to better investigate, understand, and optimize surgical techniques and equipment. FE models provide access to data such as the stress levels within the brain that would otherwise be inaccessible with the current medical technology. Brain retraction is often a dangerous but necessary part of neurosurgery, and current research focuses on minimizing trauma during the procedure. In this work, we present a simulation-based comparison of different types of retraction mechanisms. We focus on traditional spatulas and tubular retractors. Our results show that tubular retractors result in lower average predicted stresses, especially in the subcortical structures and corpus callosum. Additionally, we show that changing the location of retraction can greatly affect the predicted stress results. As the model predictions highly depend on the material model and parameters used for simulations, we also investigate the importance of using region-specific hyperelastic and viscoelastic material parameters when modelling a three-dimensional human brain during retraction. Our investigations demonstrate how FE simulations in neurosurgical techniques can provide insight to surgeons and medical device manufacturers. They emphasize how further work into this direction could greatly improve the management and prevention of injury during surgery. Additionally, we show the importance of modelling the human brain with region-dependent parameters in order to provide useful predictions for neurosurgical procedures.

Minimally Invasive Surgery of Deep-Seated Brain Lesions Using Tubular Retractors and Navigated Transcranial Magnetic Stimulation-Based Diffusion Tensor Imaging Tractography Guidance: The Minefield Paradigm

BACKGROUND

Surgical treatment of deep-seated brain lesions is a major challenge for neurosurgeons. Recently, tubular retractors have been used to help neurosurgeons in achieving the targeting and resection of deep lesions.

OBJECTIVE

To describe a novel surgical approach based on the combination of tubular retractors and preoperative mapping by navigated transcranial magnetic stimulation (nTMS) and nTMS-based diffusion tensor imaging (DTI) tractography for the safe resection of deep-seated lesions.

METHODS

Ten consecutive patients affected by deep-seated brain lesions close to eloquent motor/language/visual pathways underwent preoperative nTMS mapping of motor/language cortical areas and nTMS-based DTI tractography of adjacent eloquent white matter tracts, including optic radiations. The nTMS-based information was used to plan the optimal surgical trajectory and to guide the insertion of tubular retractors within the brain parenchyma without causing injury to the eloquent cortical and subcortical structures. After surgery, all patients underwent a new nTMS-based DTI tractography of fascicles close to the tumor to verify their structural integrity.

RESULTS

Gross total resection was achieved in 8 cases, subtotal resection in 1 case, and a biopsy in 1 case. No new postoperative deficits were observed, except in 1 case where a visual field defect due to injury to the optic radiations occurred. Postoperative nTMS-based DTI tractography showed the integrity of the subcortical fascicles crossed by tubular retractors trajectory in 9 cases.

CONCLUSION

The novel strategy combining tubular retractors with functional nTMS-based preoperative mapping enables a safe microsurgical resection of deep-seated lesions through the preservation of eloquent cortical areas and subcortical fascicles, thus reducing the risk of new permanent deficits.

Endoport-Assisted Endoscopic Surgery for Removal of Lateral Ventricular Tumors: Our Experience and Review of the Literature

Background

Endoscopic surgery has emerged in recent years as an alternative to conventional microsurgical approaches for removal of intraventricular tumors. Endoports have enhanced tumor access and visualization with a significant reduction in brain retraction.

Objective

To evaluate the safety and efficacy of endoport-assisted endoscopic technique for the removal of tumors from the lateral ventricle.

Methods

The surgical technique, complications, and postoperative clinical outcomes were analyzed with a review of the literature.

Results

Tumors were primarily located in one lateral ventricular cavity in all 26 patients, and extension to the foramen Monro and the anterior third ventricle was observed in seven and five patients, respectively. Except for three patients with small colloid cysts, all other tumors were larger than 2.5 cm. A gross total resection was performed in 18 (69%), subtotal in five (19%), and partial removal in three (11.5%) patients. Transient postoperative complications were observed in eight patients. Two patients required postoperative CSF shunting for symptomatic hydrocephalus. All patients improved on KPS scoring at a mean follow-up of 4.6 months.

Conclusions

Endoport-assisted endoscopic technique is a safe, simple, and minimally invasive method to remove intraventricular tumors. Excellent outcomes comparable to other surgical approaches can be achieved with acceptable complications.

Endoscope-Assisted Neuroportal Transcerebellar Approach to the Fourth Ventricle: An Anatomical Study

BACKGROUND AND STUDY AIMS

 Minimally invasive approaches to deep-seated lesions still represent a fundamental issue in modern neurosurgery. Tubular retractors allow to enhance the operability of intraventricular lesions, minimizing the risk of damages to brain parenchyma. Increasing interest for portal devices has been mainly focused on supratentorial pathologies, while transportal approaches in the posterior cranial fossa have been rarely described. In the present study, the authors aimed to investigate the surgical exposure and operability obtained with a microsurgical neuroportal transcerebellar approach targeting the fourth ventricle, assisted by endoscopic exploration.

MATERIAL AND METHODS

 Six cadaveric specimens were provided for anatomical microsurgical dissection and Vycor ViewSite Brain Access System was used as tubular retractor. Surgical feasibility of the neuroportal transcerebellar approach was demonstrated through a definable and measurable parameter, the operability score.

RESULTS

 The neuroport provided a surgical corridor away from eloquent structures to target the whole fourth ventricle cavity, preventing injury to cerebellar nuclei and white matter pathways and, potentially, minimizing the risk of surgical morbidity. Maximal operability was reached in the pontomedullary junction and medullary area of the ventricular floor. Transportal endoscopic assistance contributed to a further extension of surgical exposure in blind spots, corresponding to the ipsilateral lateral recess, the uppermost part of the fourth ventricle, and the obex.

CONCLUSION

 The neuroportal transcerebellar approach represents a viable alternative route to the fourth ventricle, avoiding vermian splitting or subarachnoid dissection of the cerebellomedullary cistern. Endoscopic assistance enhances the exposure of the surgical field and accomplishes a valid instrument for intraventricular orientation to ease microsurgical procedures.

Minimally Invasive Bilateral Anterior Cingulotomy via Open Minicraniotomy Using a Novel Multiport Cisternoscope: A Cadaveric Demonstration

BACKGROUND

Bilateral anterior cingulotomy has been used to treat chronic pain, obsessive compulsive disorder, and addictions. Lesioning of the target area is typically performed using bilateral stereotactic electrode placement and target ablation, which involves transparenchymal access through both hemispheres.

OBJECTIVE

To evaluate an endoscopic direct-vision lesioning using a unilateral parasagittal minicraniotomy for minimally invasive bilateral anterior cingulotomy using a novel multiport endoscope through the anterior interhemispheric fissure.

METHODS

A novel multiport magnetic resonance imaging (MRI)-compatible neuroendoscope prototype is used to demonstrate cadaveric cingulate lesioning through a lateral imaging port while simultaneously viewing the pericallosal arteries as landmarks through a tip imaging port. The lateral port enables extended lesioning of the gyrus while rotation of the endoscope about its axis provides access to homologous areas of both hemispheres.

RESULTS

Cadaver testing confirmed the capability to navigate the multiport neuroendoscope between the hemispheres using concurrent imaging from the tip and lateral ports. The lateral port enabled exploration of the gyrus, visualization of lesioning, and subsequent inspection of lesions. Tip-port imaging provided navigational cues and allowed the operator to ensure that the endoscope tip did not contact tissue. The multiport design required instrument rotation in the coronal plane of only 20° to lesion both gyri, while a standard endoscope necessitated a rotation of 54°.

CONCLUSION

Multiport MRI-compatible endoscopy can be effectively used in cisternal endoscopy, whereby a unilateral parasagittal minicraniotomy can be used for endoscopic interhemispheric bilateral anterior cingulotomy.

On-Demand Intraoperative 3-Dimensional Printing of Custom Cranioplastic Prostheses

BACKGROUND

Currently, implantation of patient-specific cranial prostheses requires reoperation after a period for design and formulation by a third-party manufacturer. Recently, 3-dimensional (3D) printing via fused deposition modeling has demonstrated increased ease of use, rapid production time, and significantly reduced costs, enabling expanded potential for surgical application. Three-dimensional printing may allow neurosurgeons to remove bone, perform a rapid intraoperative scan of the opening, and 3D print custom cranioplastic prostheses during the remainder of the procedure.

OBJECTIVE

To evaluate the feasibility of using a commercially available 3D printer to develop and produce on-demand intraoperative patient-specific cranioplastic prostheses in real time and assess the associated costs, fabrication time, and technical difficulty.

METHODS

Five different craniectomies were each fashioned on 3 cadaveric specimens (6 sides) to sample regions with varying topography, size, thickness, curvature, and complexity. Computed tomography-based cranioplastic implants were designed, formulated, and implanted. Accuracy of development and fabrication, as well as implantation ability and fit, integration with exiting fixation devices, and incorporation of integrated seamless fixation plates were qualitatively evaluated.

RESULTS

All cranioprostheses were successfully designed and printed. Average time for design, from importation of scan data to initiation of printing, was 14.6 min and average print time for all cranioprostheses was 108.6 min.

CONCLUSION

On-demand 3D printing of cranial prostheses is a simple, feasible, inexpensive, and rapid solution that may help improve cosmetic outcomes; significantly reduce production time and cost-expanding availability; eliminate the need for reoperation in select cases, reducing morbidity; and has the potential to decrease perioperative complications including infection and resorption.

Combination of the tubular retractor and brain spatulas provides an adequate operative field in surgery for deep-seated lesions: Case series and technical note

Background:

Surgeries for deep-seated lesions are challenging because making a corridor and observing the interface between lesions and normal brain tissue are difficult. The ViewSite Brain Access System, which is a clear plastic tubular retractor system, is used for resection of deep-seated lesions. However, the tapered shape of this system may result in limitation of the surgical field and cause brain injury to observe the interface between lesions and normal tissue. In this study, we evaluated the usefulness of the combination of ViewSite and brain spatulas.

Methods:

Nine patients were retrospectively identified who underwent resection of deep-seated lesions with the combination of Viewsite and brain spatulas. We assessed the extent of resection, prognosis, and quantitative brain injury from postoperative diffusion-weighed imaging (DWI).

Results:

There were four total radiographically confirmed resections. Subtotal resection in four patients and partial resection in one with central neurocytoma were achieved because these tumors were strongly adherent to the choroid plexus and ependymal veins. Only one case of metastatic tumor relapsed 6 months after surgery. The mean postoperative high signal on DWI was 3.68 ± 0.80 cm³.

Conclusions:

The combination of ViewSite and brain spatulas provides wide and adequate operative fields to observe the interface between lesions and normal tissue, and to prevent brain injury from excessive retraction pressure on the brain derived from repositioning of the ViewSite. Postoperative 3D volumetric analysis shows minimal damage to normal brain tissue. This report may provide new insight into the use of the ViewSite tubular retractor.

Third Ventricular Tumors: A Comprehensive Literature Review

Third ventricle tumors are uncommon and account for 0.6 - 0.9% of all the brain tumors. Tumors of the third ventricle are classified into primary tumors, such as colloid cysts, choroid plexus papillomas, and ependymomas, or secondary tumors, such as craniopharyngiomas, optic nerve gliomas, pineal tumors, and meningiomas. Third ventricular tumors are uncommon, and their treatment involves significant morbidity and mortality. The colloid cyst has a better surgical outcome and many approaches are available to achieve a complete cure. Choroid plexus papilloma is also a common tumor documented with its treatment majorly based on surgical resection. In addition to multiple treatment options for craniopharyngiomas, surgery is the most preferred treatment option. Ependymomas also have few treatment options, with surgical resection adopted as the first line of treatment.

Establishment of Next-Generation Neurosurgery Research and Training Laboratory with Integrated Human Performance Monitoring

Quality of neurosurgical care and patient outcomes are inextricably linked to surgical and technical proficiency and a thorough working knowledge of microsurgical anatomy. Neurosurgical laboratory-based cadaveric training is essential for the development and refinement of technical skills before their use on a living patient. Recent biotechnological advances including 3-dimensional (3D) microscopy and endoscopy, 3D printing, virtual reality, surgical simulation, surgical robotics, and advanced neuroimaging have proved to reduce the learning curve, improve conceptual understanding of complex anatomy, and enhance visuospatial skills in neurosurgical training. Until recently, few means have allowed surgeons to obtain integrated surgical and technological training in an operating room setting. We report on a new model, currently in use at our institution, for technologically integrated surgical training and innovation using a next-generation microneurosurgery skull base laboratory designed to recreate the setting of a working operating room. Each workstation is equipped with a 3D surgical microscope, 3D endoscope, surgical drills, operating table with a Mayfield head holder, and a complete set of microsurgical tools. The laboratory also houses a neuronavigation system, a surgical robotic, a surgical planning system, 3D visualization, virtual reality, and computerized simulation for training of surgical procedures and visuospatial skills. In addition, the laboratory is equipped with neurophysiological monitoring equipment in order to conduct research into human factors in surgery and the respective roles of workload and fatigue on surgeons' performance.

The Changing Face of Technologically Integrated Neurosurgery: Today's High-Tech Operating Room

Over the last decade, surgical technology in planning, mapping, optics, robotics, devices, and minimally invasive techniques has changed the face of modern neurosurgery. We explore the current advances in clinical technology across all neurosurgical subspecialties, examine how clinical practice is being shaped by this technology, and suggest what the operating room of tomorrow may look like.

Resection of tumors of the third ventricle involving the hypothalamus: effects on body mass index using a dedicated surgical approach

Resection of large lesions growing into the third ventricle is considered nowadays still a demanding surgery, due to the high risk of severe endocrine and neurological complications. Some neurosurgical approaches were considered in the past the procedures of choice to access the third ventricle, however they were burden by endocrine and neurological consequences, like memory loss and epilepsy. We report here the endocrine and functional results in a series of patients operated with a recently developed approach specifically tailored for the resection of large lesions growing into the third ventricle. Authors conducted a retrospective analysis on 10 patients, operated between 2011 and 2012, for the resection of large tumors growing into the third ventricle. Total resection was achieved in all patients. No perioperative deaths were recorded and all patients were alive after the follow-up. One year after surgery 8/10 patients had an excellent outcome with a Karnofsky Performance Status of 100 and a Glasgow Outcome score of 5, with 8 patients experiencing an improvement of the Body Mass Index. Modern neurosurgery allows a safe and effective treatment of large lesions growing into the third ventricle with a postoperative good functional status.

Microsurgical endoscopy-assisted anterior corpus callosotomy for drug-resistant epilepsy in an adult unresponsive to vagus nerve stimulation

Because most of the corpus callosotomy (CC) series available in literature were published before the advent of vagus nerve stimulation (VNS), the efficacy of CC in patients with inadequate response to VNS remains unclear, especially in adult patients. We present the case of a 21-year-old female with medically refractory drop attacks that began at the age of 8 years, which resulted in the patient being progressively unresponsive to vagus nerve stimulation implanted at the age of 14 years. Corpus callosotomy was recommended to reduce the number of drop attacks. However, the patient had only mild cognitive impairments and no neurological deficits. For this reason, we were forced to plan a surgical approach able to maximize the disconnection for good seizure control while, at the same time, minimizing sequelae from disconnection syndromes and neurosurgical complications because in such cases of long-lasting epilepsy the gyri cinguli and the arteries can be tenaciously adherent and dislocated with all the normal anatomy altered. In this scenario, we opted for a microsurgical endoscopy-assisted anterior two-thirds corpus callosotomy. The endoscopic minimally invasive approach proved to be quite adequate in this technically demanding case and confirmed that CC may offer advantages, with good results, even in adult patients with drop attacks who have had inadequate response to VNS.