Brain retraction injury

Intrasylvian Retraction Technique to Facilitate the Sylvian Fissure Dissection: A Clinical Study of 125 Cases

Although many authors have recommended the retractorless technique to avoid retractor-induced brain injury, others usually use brain retractors with a meticulous technique to facilitate the surgery, especially for sylvian fissure dissection. The intrasylvian retraction technique was described for sylvian fissure opening, but no clinical evidence was found. We evaluate the efficacy and safety of this technique for the distal transsylvian approach. We reviewed the video records of clinical cases where the distal transsylvian approach was performed using the intrasylvian retraction technique for aneurysm treatment and middle cerebral artery (MCA) bypass between September 2018 and August 2022. Operative techniques are described. The efficacy and safety of the technique were assessed by full exposure of the sylvian fissure and new postoperative perisylvian hematoma, respectively. One hundred twenty-five cases were included and had an average age of 53.5 (range 16-85) years. Women comprised 73.6%. Aneurysm surgery, pure MCA revascularization, and aneurysm surgery with MCA revascularization were 106 (84.8%), 12 (9.6%), and 7 cases (5.6%), respectively. The most common aneurysm location was the internal carotid artery-posterior communicating artery junction in 37 cases (34.9%), followed by the anterior communicating artery in 27 (25.5%). Full exposure of the Sylvian fissure was achieved in all cases. No perisylvian hematoma was detected by immediate postoperative computed tomography in any patient. Using an appropriate technique for brain retractor application, sylvian fissure dissection was safely performed. The intrasylvian retraction technique effectively facilitated sylvian fissure dissection and provided wide exposure for the distal transsylvian approach.

Exoscopic Retrosigmoid Approach for an Anteromedial Tentorial Meningioma: 2D Operative Video

We present a 2-dimensional operative video (Video 1) of a suboccipital retrosigmoid approach for an anteromedial tentorial meningioma with a specific focus on the use of a surgical exoscope. The patient is a 50-year-old woman who presented to emergency room with a 6-month history of nausea, dizziness, and gait imbalance secondary to a 2.5-cm homogenously enhancing mass originating from the anteromedial tentorium on the right side with associated brainstem compression. Retrosigmoid craniotomy was selected due to the favorable surgical corridor for resection and lower risk of cerebrospinal fluid leak, hearing loss, and seizures compared with other approaches.1-5 The patient consented to the procedure. Video 1 emphasizes the advantages of the exoscope compared with the microscope in optimizing surgeon efficiency, ergonomics, and comfort.6 The unique operating room setup associated with exoscope use is highlighted. The patient underwent uncomplicated gross total resection with a mild trochlear nerve palsy noted postoperatively that was resolved at follow-up.7.

Minimally invasive resection of intracranial lesions using tubular retractors: A single surgeon series

OBJECTIVE

Tubular retractors are increasingly used due to their low complication rates, providing easier access to lesions while minimizing trauma from brain retraction. Our study presents the most extensive series of cases performed by a single surgeon aiming to assess the effectiveness and safety of a transcortical-transtubular approach for removing intracranial lesions.

METHODS

We performed a retrospective review of patients who underwent resection of an intracranial lesion with the use of tubular retractors. Electronic medical records were reviewed for patient demographics, preoperative clinical deficits, diagnosis, preoperative and postoperative magnetic resonance imaging (MRI) scans, lesion characteristics including location, volume, extent of resection (EOR), postoperative complications, and postoperative deficits.

RESULTS

112 transtubular resections for intracranial lesions were performed. Patients presented with a diverse number of pathologies including metastasis (31.3 %), GBM (21.4 %), and colloid cysts (19.6 %) The mean pre-op lesion volume was 14.45 cm3. A gross total resection was achieved in 81 (71.7 %) cases. Seventeen (15.2 %) patients experienced early complications which included confusion, short-term memory difficulties, seizures, meningitis and motor and visual deficits. Four (3.6 %) patients had permanent complications, including one with aphasia and difficulty finding words, another with memory loss, a third with left-sided weakness, and one patient who developed new-onset long-term seizures. Mean post-operative hospitalization length was 3.8 days.

CONCLUSION

Tubular retractors provide a minimally invasive approach for the extraction of intracranial lesions. They serve as an efficient tool in neurosurgery, facilitating the safe resection of deep-seated lesions with minimal complications.

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.

Utilizing tubular retractors in colloid cyst resection: A single surgeon experience

Background

Colloid cysts are intracranial lesions originating from abnormalities in the primitive neuroepithelium folding of the third ventricle. Various surgical approaches have been explored for the management of colloid cysts, each carrying its own set of advantages and limitations. Tubular retractors developed recently alleviate retraction pressure through radial distribution, potentially offering benefits for colloid cyst resection. This study aims to introduce and assess a modified microsurgical method utilizing the tubular retractor for addressing colloid cysts.

Methods

The study included a retrospective assessment of patients who had colloid cysts and who were treated between 2015 and 2023 by one experienced surgeon. The demographic, clinical, radiological, histological, and surgical data regarding these patients were evaluated. The patients were assessed using the colloid cyst risk score, indicating a risk for obstructive hydrocephalus.

Results

The minimally invasive microsurgical approach was successfully applied to all 22 identified patients. No postoperative surgical complications were reported. Gross total resection was achieved in 21 (95.5%) patients. The early complication rate was 22.7% (n = 5). There were no postoperative seizures, permanent neurological deficits, or venous injuries. The average hospital stay was 3 days. There was no evidence of recurrence at an average follow-up length of 25.9 months.

Conclusion

The transtubular approach is an effective, safe method for treating colloid cysts. It achieves complete cyst removal with minimal complications, offering the benefits of less invasiveness, improved visualization, and reduced tissue disruption, strengthening its role in colloid cyst surgery.

A Novel Foley Catheter-Based Brain Retraction Method for the Interhemispheric Approach: Technical Considerations and an Illustrative Video

BACKGROUND

Management of interhemispheric pathologies requires surgical intervention through a restricted anatomical corridor ensconced within critical cerebral structures. The use of retractors to facilitate operative access may cause damage to cerebral tissue. The development of an innovative retraction technique designed to alleviate cerebral damage in such cases is imperative. In this study, we present a novel and gentle retraction method to facilitate the interhemisferic approach.

METHODS

We retrospectively examined data of 9 right-handed patients who underwent surgical resection of interhemispheric lesions between 2021 and 2022. All patients underwent surgery for the first time because of this pathology. All operative specimens were histologically confirmed. Clinical characteristics, operative details, and follow-up data were retrospectively analyzed.

RESULTS

The new retraction technique was successfully applied to 8 tumor patients and 1 patient with an aneurysm. Eight patients had an anterior interhemispheric approach, and 1 patient had a posterior interhemispheric approach. Complete surgical excision was achieved in all patients with no postoperative complications. Postoperative Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) showed no signs of ischemia or contusion. All patients exhibited significant improvements in their symptoms. An illustrative video that elucidates the removal of an interhemispheric epidermoid tumor, employing the anterior ipsilateral interhemispheric approach, featuring the novel retraction method.

CONCLUSIONS

The ideal retraction technique during the interhemispheric approach is still a challenge. Our novel retraction technique may help minimize brain parenchymal damage during surgical resection of interhemispheric lesions.

Efficacy of propofol-based anesthesia against risk of brain swelling during craniotomy: A meta-analysis of randomized controlled studies

STUDY OBJECTIVE

This meta-analysis aimed to compare the risk of brain swelling during craniotomy between propofol-based and volatile-based anesthesia.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

SETTING

Operating room.

INTERVENTION

Propofol-based anesthesia.

PATIENTS

Adult patients undergoing craniotomy.

MEASUREMENTS

Databases, including EMBASE, MEDLINE, Google Scholar, and Cochrane Library, were searched from inception to April 2023. The primary outcome was the risk of brain swelling, while the secondary outcomes included the impact of anesthetic regimens on surgical and recovery outcomes, as well as the risk of hemodynamic instability.

MAIN RESULTS

Our meta-analysis of 17 RCTs showed a significantly lower risk of brain swelling (risk ratio [RR]: 0.85, p = 0.03, I2 = 21%, n = 1976) in patients receiving propofol than in those using volatile agents, without significant differences in surgical time or blood loss between the two groups. Moreover, propofol was associated with a lower intracranial pressure (ICP) (mean difference: -4.06 mmHg, p < 0.00001, I2 = 44%, n = 409) as well as a lower risk of tachycardia (RR = 0.54, p = 0.005, I2 = 0%, n = 822) and postoperative nausea/vomiting (PONV) (RR = 0.59, p = 0.002, I2 = 19%, n = 1382). There were no significant differences in other recovery outcomes (e.g., extubation time), risk of bradycardia, hypertension, or hypotension between the two groups. Subgroup analysis indicated that propofol was not associated with a reduced risk of brain swelling when compared to individual volatile agents. Stratified by craniotomy indications, propofol reduced brain swelling in elective craniotomy, but not in emergency craniotomy (e.g., traumatic brain injury), when compared to volatile anesthetics.

CONCLUSIONS

By reviewing the available evidence, our results demonstrate the beneficial effects of propofol on the risk of brain swelling, ICP, PONV, and intraoperative tachycardia. In emergency craniotomy for traumatic brain injury and subarachnoid hemorrhage, brain swelling showed no significant difference between propofol and volatile agents. Further large-scale studies are warranted for verification.

Endoport-Guided Endoscopic Excision of Intraaxial Brain Tumors

OBJECTIVE

Transcortical approaches using a spatula-based retraction system have traditionally been used for the microsurgical resection of deep-seated intraventricular and parenchymal brain tumors. Recently, transparent cylindrical or tubular retractors have been developed to provide a stable corridor to access deeper brain lesions and perform bimanual microsurgical resection. The flexible endoports minimize brain retraction injury during surgery and, along with the superior vision of endoscopes, offer several advantages over standard microsurgery. In this chapter, we describe the surgical technique of the endoport-guided endoscopic excision of deep-seated intraaxial brain tumors.

METHODS

The endoscopic endoport technique that we use at our institution for the surgical management of intraventricular and intraparenchymal brain tumors has been described in detail with illustrative cases.

RESULTS

Results from the literature review of intraventricular and intraparenchymal port surgery were analyzed, and the feasibility and safety of this technique were discussed. Surgical complication avoidance and management were highlighted. The port technique offers numerous potential advantages, including (1) reducing focal brain injury by distributing retraction forces homogenously, (2) minimizing white matter disruption and the risk of fascicle injury during cannulation, (3) ensuring the stability of the surgical corridor during the procedure, (4) preventing inadvertent expansion of the corticectomy and white fiber tract dissection throughout surgery, and (5) protecting the surrounding tissues against iatrogenic injuries caused by instrument entry and reentry.

CONCLUSION

The endoport-assisted endoscopic technique is safe and offers an effective alternative option for the resection of intraventricular and intraparenchymal lesions.

Impact of Preoperative Mapping and Intraoperative Neuromonitoring in Minimally Invasive Parafascicular Surgery for Deep-Seated Lesions

BACKGROUND

Transsulcal tubular retractor-assisted minimally invasive parafascicular surgery changes the surgical strategy for deep-seated lesions by promoting a deficit-sparing approach. When integrated with preoperative brain mapping and intraoperative neuromonitoring (IONM), this approach may potentially improve patient outcomes. In this study, we assessed the impact of preoperative brain mapping and IONM in tubular retractor-assisted neuro-oncological surgery.

METHODS

This retrospective single-center cohort study included patients who underwent transsulcal tubular retractor-assisted minimally invasive parafascicular surgery for resection of deep-seated brain tumors from 2016 to 2022. The cohort was divided into 3 groups: group 1, no preoperative mapping or IONM (17 patients); group 2, IONM only (25 patients); group 3, both preoperative mapping and IONM (38 patients).

RESULTS

We analyzed 80 patients (33 males and 47 females) with a median age of 46.5 years (range: 1-81 years). There was no significant difference in mean tumor volume (26.2 cm3 [range 1.07-97.4 cm3]; P = 0.740) and mean preoperative depth of the tumor (31 mm [range 3-65 mm], P = 0.449) between the groups. A higher proportion of high-grade gliomas and metastases was present within group 3 (P = 0.003). IONM was related to fewer motor (P = 0.041) and language (P = 0.032) deficits at hospital discharge. Preoperative mapping and IONM were also related to shorter length of stay (P = 0.008).

CONCLUSIONS

Preoperative and intraoperative brain mapping and monitoring enhance transsulcal tubular retractor-assisted minimally invasive parafascicular surgery in neuro-oncology. Patients had a reduced length of stay and prolonged overall survival. IONM alone reduces postoperative neurological deficit.

Brain retraction injury: systematic literature review

Cerebral retraction is frequently required in cranial surgery to access deep areas. Brain retractors have been systematically used in the past, but they have been associated with brain injury. Nonetheless, they are still used and, even recently, new systems have been advocated. The aim of this study is to provide a systematic and critical review of brain retraction injury. A systematic literature review was performed in February 2023 according to PRISMA statement. Search terms included brain retraction and injury, with their variations and pertinent associations. Studies reporting qualitative and quantitative data on brain retraction injury were included. Out of 1689 initially retrieved articles, 90 and 26 were included in the systematic review for qualitative and quantitative data, respectively. The definition of brain retraction injury varies and its reported incidence in clinical studies is 5-10%, up to 47% if cerebral edema is considered. Some studies have hypothesized threshold values of pressures to be respected in order to prevent complications, with most data deriving from animal studies. At present, there are no instruments for brain retraction that can guarantee full safety. Some form of cerebral retraction might always be necessary for specific scenarios. Further studies are needed to collect quantitative and, ideally, clinical and comparative data on pressure thresholds to develop retraction systems that can reduce injury to a minimum.

Use of tubular retractors to access deep brain lesions: A case series

BACKGROUND

Deep-seated intracranial lesions can be accessed using blade retractors that may disrupt white matter tracts, exert pressure on adjacent tissue, and lead to post-operative venous injury. Tubular retractors may minimize disruption to white matter tracts by radially dispersing pressure onto surrounding tissue. This study characterizes perioperative outcomes in patients undergoing biopsy or resection of intracranial pathologies using tubular retractors.

METHODS

Adult patients (≥18 years) undergoing neurosurgical intervention using tubular retractors at a single health system (January 2016-February 2022) were identified through chart review. Demographics, disease characteristics, management data, and clinical outcomes were collected.

RESULTS

A total of 49 patients were included; 23 (47%) had primary brain tumors, 8 (16%) metastases, 6 (12%) intracranial hemorrhage (ICH), 5 (10%) cavernomas, and 7 (14%) other pathologies. Lesions were located subcortically (n = 19, 39%), intraventricularly (n = 15, 31%), and in deep gray matter (n = 11, 22%). Gross total resection (GTR) or near GTR was achieved in 21 of 26 (80.8%) patients with intracranial lesions where GTR was the goal of surgery; 10 of 11 (90.9%) biopsies in patients with masses were diagnostic. Five of six (83.3%) ICHs were totally or near totally evacuated. Seventeen patients (35%) had major complications post-operatively. The most common complications were DVT/PE (n = 7, 14%) and seizures (n = 6, 12%). For patients who experienced post-operative seizures, 3 had seizures preoperatively and 1 had seizures in the context of electrolyte derangements. No patients died of post-operative complications.

CONCLUSION

This operative approach may facilitate safe and efficacious biopsy or resection of deep-seated intracranial pathologies.

Using artificial intelligence to quantify dynamic retraction of brain tissue and the manipulation of instruments in neurosurgery

PURPOSE

There is no objective way to measure the amount of manipulation and retraction of neural tissue by the surgeon. Our goal is to develop metrics quantifying dynamic retraction and manipulation by instruments during neurosurgery.

METHODS

We trained a convolutional neural network (CNN) to analyze microscopic footage of neurosurgical procedures and thereby generate metrics evaluating the surgeon's dynamic retraction of brain tissue and, using an object tracking process, evaluate the surgeon's manipulation of the instruments themselves. U-Net image segmentation is used to output bounding polygons around cerebral parenchyma of interest, as well as the vascular structures and cranial nerves. A channel and spatial reliability tracker framework is used in conjunction with our CNN to track desired surgical instruments.

RESULTS

Our network achieved a state-of-the-art intersection over union ([Formula: see text]) for biological tissue segmentation. Multivariate statistical analysis was used to evaluate dynamic retraction, tissue handling, and instrument manipulation.

CONCLUSION

Our model enables to evaluate dynamic retraction of soft tissue and manipulation of instruments during a surgical procedure, while accounting for movement of the operative microscope. This model can potentially provide the surgeon with objective feedback about the movement of instruments and its effect on brain tissue.

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.

Development of Haptic Interface for Neurosurgical Simulators with Micro Scissors Module for Displaying the Cutting Force

Introduction of surgical simulators, which enable repeated learning of new surgical techniques, is advancing and they are desired in the field of neurosurgery. This study aims to make a two-fold contribution. First is the development of a haptic interface, which can be used while changing the operative tools necessary for training the cerebral fissure opening technique while using both the hands. Second is to develop a module for the haptic interface, which can display the cutting force when using micro scissors. To realize the operation with both the hands, the haptic interfaces for the right and left hands are designed so that they do not interfere. In addition, surgical tools, such as retractors, micro dissectors, and micro scissors, can be exchanged. In the cutting experiment carried out prior to the development of the haptic interface, it was clarified that the force when the dura mater was cut using micro scissors was 0.5 N. For comparison, the cutting forces required to cut two and three sheets of paper were measured to be 0.4 N and 0.6 N, respectively. The developed micro scissors module was designed using one motor and planetary gear mechanism. The gear mechanism is designed such that the right and left handles rotate in reverse directions around the rotation axis of the micro scissors using only one motor. This mechanism enables the micro scissors to cut the virtual tissues in the middle of the blade. The developed module could display a force of 0.4 N.

Clinical effectiveness of hypertonic sodium lactate infusion for intraoperative brain relaxation in patients undergoing scheduled craniotomy for supratentorial brain tumor resection: A study protocol of a single center double-blind randomized controlled phase II pilot trial

INTRODUCTION

Hyperosmolar solutions are prescribed in neurosurgery patients to provide satisfactory intraoperative brain relaxation and to lower cerebral injuries related to surgical retractors. Mannitol is traditionally considered as the first-choice solution for brain relaxation in neurosurgery patients. Hypertonic sodium lactate infusion was reported to provide a higher and longer osmotic effect compared to mannitol in severely brain-injured patients and to prevent impaired cerebral energetics related to brain injuries. To date, the clinical effectiveness of hypertonic sodium lactate infusion has never been studied in neurosurgery patients. The hypothesis of the study is that hyperosmolar sodium lactate infusion may provide satisfactory intraoperative brain relaxation in patients undergoing scheduled craniotomy for supratentorial brain tumor resection.

METHODS AND ANALYSIS

We designed a phase II randomized, controlled, double-blind, single-center pilot trial, and aim to include 50 adult patients scheduled for craniotomy for supratentorial brain tumor resection under general anesthesia. Patients will be randomized to receive either mannitol (conventional group) or hypertonic sodium lactate (intervention group) infusion at the time of skin incision. Brain relaxation (primary outcome) will be assessed immediately after opening the dura by the neurosurgeon blinded to the treatment allocated using a validated 4-point scale. The primary outcome is the proportion of satisfactory brain relaxation, defined as brain relaxation score of 3 or 4.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee (Comité de Protection des Personnes Est III) and authorized by the French Health Authority (Agence Nationale de Sécurité des Médicaments, Saint-Denis, France). The University Hospital of Besancon is the trial sponsor and the holder of all data and publication rights. Results of the study will be submitted for publication in a peer-review international medical journal and for presentation in abstract (oral or poster) in international peer-reviewed congresses.

REGISTRATION

The trial is registered with ClinicalTrials.gov (Identifier: NCT04488874, principal investigator: Prof Guillaume Besch, date of registration: July 28, 2020).

Wide Dissection Trans-Sulcal Approach for Resection of Deep Intra-Axial Lesions in Eloquent Brain Areas

Introduction: Resection of intra-axial tumors (IaT) in eloquent brain regions risks major postoperative neurological deficits. Awake craniotomy is often used to navigate these areas; however, some patients are ineligible for awake procedures. The trans-sulcal approach (TScal) was introduced to reduce parenchymal trauma during tumor resection. We report our experiences utilizing TScal for resection of deep IaT located in eloquent areas. Materials and Methods: This is a single-center retrospective analysis of patients who underwent IaT resection in eloquent areas via TScal from January 2013 to April 2021. Seventeen cases were reviewed, and relevant data was collected. Fluorescence-guided surgery with 5-aminolevulinic acid (ALA) and intraoperative ultrasound was performed in some cases. Results: Seventeen patients (10 males, 7 females) averaging 61.2 years-old (range, 21-76) were included in this study. Average length of stay was 4.8 days, and only 2 patients (11.8%) required hospital readmission within 30 days. Gross total resection (GTR) was achieved in 15 patients (88.2%), while subtotal resection occurred in 2 patients (11.8%). Eleven patients (64.7%) reported full resolution of symptoms, 4 patients (23.5%) reported deficit improvement, and 2 patients (11.8%) experienced no change from their preoperative deficits. No patient developed new permanent deficits postoperatively. Discussion: GTR, preoperative deficit reduction, and complications were comparable to awake craniotomy and other TScal studies. Ancillary intraoperative techniques, such as brain mapping, 5-ALA and intraoperative ultrasound, are afforded by TScal to improve resection rates and overall outcomes. Conclusions: TScal can be an option for patients with deep lesions in eloquent areas who are not candidates for awake surgeries.

Criteria for Cerebrospinal Fluid Diversion in Retractorless Sphenoid Wing Meningioma Surgery: A Technical Report

Objective  Sphenoid wing meningiomas (SWMs) can present surgical challenges, in that they are often obscured by overlying brain, encase critical neurovascular structures, and obliterate cerebrospinal fluid (CSF) cisterns. While brain retraction can enable access, its use can have potentially deleterious effects. We report the benefits and outcomes of the criteria we have developed for use of cerebrospinal diversion to perform retractorless surgery for SWMs. Design  Technical report. Setting  Yale School of Medicine and Yale New Haven Hospital. Participants  Between May, 2019 and December, 2020, ten consecutive patients were included who met the presented criteria for SWM surgery with preoperative lumbar drain (LD) placement. Main Outcome Measures  Length of hospital stay, surgical complications, and extent of resection. Results  We have developed the following criteria for LD placement in patients with SWMs such that LDs are preoperatively placed in patients with tumors with one or more of the following criteria: (1) medial location along the sphenoid wing, (2) vascular encasement resulting in obliteration of the optic carotid cistern and/or proximal sylvian fissure, and/or (3) the presence of associated edema. CSF release, after craniotomy and sphenoid wing removal, allowed for optimization of exposure, leading to the maximal safe extent of tumor resection without brain retraction or any complications. Conclusions  Preoperative LD placement is effective in allowing for maximal extent of resection of SWMs and may be considered in cases where local CSF release is not possible. This technique is useful in those tumors located more medially, with encasement of the vasculature and/or associated with edema.

Continuous Microdebrider-Based Dynamic Subcortical Motor Mapping: A Technical Advance in Tubular Retractor-Assisted Surgery

BACKGROUND

Transsulcal minimally invasive parafasicular (TsMIP) approaches to brain tumor resection use tubular retractors to minimize iatrogenic brain injury. Dynamic cortical and subcortical continuous neurophysiological mapping facilitates safer resection of motor-eloquent tumors.

OBJECTIVE

To describe a new technique to address the challenge of combining TsMIP with tubular retractors and dynamic subcortical mapping using a single electrified stimulating microdebrider instrument.

METHODS

We adapted the NICO Myriad microdebrider with continuous monopolar stimulation electrification using high-frequency stimulation with the train-of-5 technique. We performed continuous subcortical mapping using this device and compared it with standard dynamic monopolar subcortical mapping using a suction stimulation device. We found no significant difference in recorded stimulation response.

RESULTS

Using a single operating instrument that provides synchronous tumor resection and monopolar subcortical mapping with the NICO Brainpath tubular retractor, we observed increased degrees of movement, faster surgical resection times with an enlarged working channel down the retractor, and improved safety because the stimulating probe sits 2 mm deep to the resection window.

CONCLUSION

We show that the adapted device is reliable and provides similar stimulation response as conventional subcortical mapping. We advocate the use of our adapted microdebrider in TsMIP tubular retractor approaches.

Using the ROSA Robot for Lesion Resection: A Novel Adapter With Added Applications

BACKGROUND

The ROSA robot (Medtech) has been shown to be a useful instrument in the surgeon's armamentarium for accurate placement of stereotactic electroencephlography depth electrodes. However, it has not yet been used as a navigation tool for lesion resection. Here, we demonstrate a novel adapter that allows the surgeon to use the ROSA robot with the NICO BrainPath for the resection of deep lesions.

OBJECTIVE

To demonstrate the utility of an adapter that allows the ROSA robot to be used in conjunction with the NICO BrainPath tube for lesion resection.

METHODS

A stainless steel adapter was made based on the specifications of the ROSA pointer instrument. Two 3D printed models were used to undergo a "mock" surgery using the adapter to assess for ease of use and applicability.

RESULTS

The adapter allowed for adequate accessibility and visualization of the tumors in both mock cases. In addition, the stability of the ROSA robot and the design of the adapter allowed the surgeon to rest their hands on the instrument without jeopardizing its position.

CONCLUSION

The ROSA adapter allowed for accurate navigation and exposure of these lesions, combining the accuracy and stability of the ROSA robot, with the retraction of the BrainPath tube.

Brain retraction injury after elective aneurysm clipping: a retrospective single-center cohort study

Background

BRI is estimated to occur in 10% of skull-base surgery and 5% of aneurysm surgery. These estimates are based on a few studies with unclear methodology. The purpose of this study is to assess the rate of BRI occurrence, its risk factors, and the association between BRI and postoperative focal neurological deficit in patients that underwent elective aneurysm surgery in a single institution.

Methods

All patients that underwent elective aneurysm surgery in a single tertiary center in the Netherlands were included. BRI was defined as cortical hypodensities in the surgical trajectory not matching areas of large arterial infarction. Risk ratios were calculated between BRI and (a) the use of temporary parent artery occlusion during clipping, (b) anterior communicating artery (ACom), and (c) middle cerebral artery (MCA) location of the aneurysm, (d) presence of mentioned CVA risk factors, (e) the clipping of > 1 aneurysm during the same procedure, and (f) new focal neurological deficit. Statistical analysis further included t-tests and binary logistical regression analysis on the correlation between age and BRI.

Results

BRI was identified postoperatively in 42 of the 94 patients included in this study. A new focal neurological deficit was found in 7 patients in the BRI group. A total of 5 patients had persisting symptoms at 3-month follow-up, of which 2 were caused by BRI. Increasing age is a risk factor for developing BRI.

Conclusions

The high rate of BRI and significant risk of new postoperative focal neurological deficit in our patients should be considered when counseling patients for elective aneurysm surgery.

A Low Subfrontal Dural Opening for Operative Management of Anterior Skull Base Lesions

Introduction A low subfrontal dural opening technique that limits brain manipulation was assessed in patients that underwent frontotemporal approaches for anterior fossa lesions. Methods A retrospective review was performed for cases using a low subfrontal dural opening including characterization of demographics, lesion size and location, neurological and ophthalmological assessments, clinical course, and imaging findings. Results A low subfrontal dural opening was performed in 23 patients (17F, 6M), median age of 53 years (range 23-81) with median follow-up duration of 21.9 months (range 6.2-67.1). Lesions included 22 meningiomas (9 anterior clinoid, 12 tuberculum sellae, and 1 sphenoid wing), 1 unruptured internal carotid artery aneurysm clipped during a meningioma resection, and 1 optic nerve cavernous malformation. Maximal possible resection was achieved in all cases including gross total resection in 16/22 (72.7%), near total in 1/22 (4.5%), and subtotal in 5/22 (22.7%) in which tumor involvement of critical structures limited complete resection. Eighteen patients presented with vision loss; 11 (61%) improved postoperatively, 3 (17%) were stable, and 4 (22%) worsened. The mean ICU stay and time to discharge was 1.3 days (range 0-3) and 3.8 days (range 2-8). Conclusions A low subfrontal dural opening for approaches to the anterior fossa can be performed with minimal brain exposure, early visualization of the optico-carotid cistern for cerebrospinal fluid release, minimizing need for fixed brain retraction and Sylvian fissure dissection. This technique can potentially reduce surgical risk and provide excellent exposure for anterior skull base lesions with favorable extent of resection, visual recovery, and complication rates.

Early Minimally Invasive Parafascicular Surgery for Evacuation of Spontaneous Intracerebral Hemorrhage in the Setting of Computed Tomography Angiography Spot Sign: A Case Series

BACKGROUND

Spontaneous intracerebral hemorrhage (sICH) is associated with high morbidity and mortality, and the role of surgery is uncertain. Spot sign on computed tomography angiography (CTA) has previously been seen as a contraindication for minimally invasive techniques.

OBJECTIVE

To demonstrate the use of minimally invasive parafascicular surgery (MIPS) for early evacuation of sICH in patients with spot sign on CTA.

METHODS

Retrospective review of patients presenting to a US tertiary academic medical center from 2018 to 2020 with sICH and CTA spot sign who were treated with MIPS within 6 h of arrival.

RESULTS

Seven patients (6 men and 1 woman, mean age 54.4 yr) were included in this study. There was a significant decrease between preoperative and postoperative intracerebral hemorrhage volumes (75.03 ± 39.00 cm3 vs 19.48 ± 17.81 cm3, P = .005) and intracerebral hemorrhage score (3.1 ± 0.9 vs 1.9 ± 0.9, P = .020). The mean time from arrival to surgery was 3.72 h (±1.22 h). The mean percentage of hematoma evacuation was 73.78% (±21.11%). The in-hospital mortality was 14.29%, and the mean modified Rankin score at discharge was 4.6 (±1.3). No complications related to the surgery were encountered in any of the cases, with no abnormal intraoperative bleeding and no pathology demonstrating occult vascular lesion.

CONCLUSION

Early intervention with MIPS appears to be a safe and effective means of hematoma evacuation despite the presence of CTA spot sign, and this finding should not delay early intervention when indicated. Intraoperative hemostasis may be facilitated by the direct visualization provided by a tubular retractor system.

Soft Robotic Deployable Origami Actuators for Neurosurgical Brain Retraction

Metallic tools such as graspers, forceps, spatulas, and clamps have been used in proximity to delicate neurological tissue and the risk of damage to this tissue is a primary concern for neurosurgeons. Novel soft robotic technologies have the opportunity to shift the design paradigm for these tools towards safer and more compliant, minimally invasive methods. Here, we present a pneumatically actuated, origami-inspired deployable brain retractor aimed at atraumatic surgical workspace generation inside the cranial cavity. We discuss clinical requirements, design, fabrication, analytical modeling, experimental characterization, and in-vitro validation of the proposed device on a brain model.

[Brain retraction injury]

This review is devoted to various techniques for reduction of brain damage during retraction. Searching for reports was carried out in Russian and English languages using the PubMed database (n=721) without restrictions on language, date and study design according to the following keywords: «brain retraction injury», «spatula brain retractors», «tubular brain retractors», «retractorless neurosurgery». Primary screening and exclusion of duplicate manuscripts allowed us to single out the main group of articles (n=121). Some reports were excluded due to non-compliance with inclusion criteria (no description of methods, few references and insufficient data). The final list included 32 studies which were represented by cohort studies, retrospective analyses of surgical interventions, as well as experimental and laboratory studies. Small number of publications did not allow us to obtain unambiguous conclusions. Further research is required to reduce brain retraction trauma.

Microsurgical endoportal MRI/US-navigated approach for the resection of large intraventricular tumours: a 20-consecutive patients case series

OBJECTIVES

Deep lesions located in lateral and third ventricles can be accessed thorough interhemispheric transcallosal or transcortical trans-ventricular approaches. Traditional brain retractors are made by 'non-cerebral engineered' spatulas, which do not equally distribute pressure on surrounding structures damaging brain. In this paper, we present a series of 20 intraventricular tumours resected through a MRI/US-navigated microscopic transcortical endoportal approach.

PATIENTS AND METHODS

Between January 2014 and December 2017, 20 patients underwent US-MRI neuronavigated (Esaote^®, Genova, Italy) transcortical endoportal (Vycor^® Viewsite Brain Access System TC Model, Vycor^® Medical Inc., Boca Raton, FL) surgery for intraventricular deep-seated lesions with the intent to reach maximal safe resection.

RESULTS

Gross total removal was achieved in 14 patients (70%). The only prognostic factor that resulted in statistical significance related to surgical radicality from multivariate analysis was white matter infiltration (p = 0.043), regardless of other tumour (dimensions, origin and location inside ventricular system, histopathology) and patient (age, gender, clinical presentation) characteristics. The mean duration of surgery was 225.9 min (± 59). Neither critical events, nor major bleedings, nor intraoperative deaths occurred during surgery. One case of postoperative CSF infection (5%) was registered. Six patients (30%) required permanent CSF drainage system (Ommaya reservoir, VP shunt) in the postoperative period. The mean Functional Independence Measure (FIM) score at last follow-up was 105 (range: 65-124).

CONCLUSIONS

Transcortical transventricular endoportal surgery seems to be a valuable alternative to transcallosal surgery, although further prospective multicentre studies with larger number of patients, evaluation of pre- and post-operative neuropsychological outcomes and achievement of postoperative DTI and f-MRI are needed to confirm our results.

Retractorless brain surgery: technical considerations

Background

Retraction is necessary to access deep areas in the brain and skull base, but prolonged and forceful use of fixed retraction might be injurious. Several techniques were developed, in the concept of minimally invasive neurosurgery, to eliminate or minimize the use of fixed retractors. The authors discuss the technical considerations and limits in applying dynamic retraction in brain surgery for a variety of lesions using different approaches.

Results

We retrospectively collected 123 cases with brain lesions in diverse locations, were dynamic retraction, using the tools in the operator hands and was achieved successfully instead of fixed retraction. Cases with aneurysms were excluded, although retraction was applied during clipping only. Superficial and large masses that do not require fixed retraction as a routine were excluded also. We relied mainly on patient positioning to benefit from the gravity, proper design of the craniotomy, arachnoid dissection, cerebrospinal fluid aspiration, and internal decompression of the mass when possible.

Different approaches for different lesions were utilized in our patients, subfrontal or pterional and their modifications in 45.5% of cases, suboccipital in 21.1%, retrosigmoid in 13%, the interhemispheric approach in 10.5%, transcortical to lateral ventricles in 7.3%, and posterior subtemporal in 2.4%.

Dynamic retraction with the surgical tools was used successfully in all cases except 7 patients (5.6%) where we had to use fixed retraction transiently.

Conclusion

Several considerations are helpful and amenable to achieve successful brain surgery without fixed retraction. Utilizing the gravity, unlocking of the brain, choosing the surgical corridor, cerebrospinal fluid suctioning, and mastering of the microsurgical techniques are the keys.

Resection of intra- and paraventricular malignant brain tumors using fluorescein sodium-guided neuroendoscopic transtubular approach

BACKGROUND

The requirement of brain retraction and difficulty in distinguishing the tumor demarcation are challenging in conventional approaches to intra- and paraventricular malignant tumors (IV-PVMTs). Tubular retractors can minimize the retraction injury, and fluorescein-guided (FG) surgery may promote the resection of tumors. Our aim is to evaluate the feasibility, safety, and effectiveness of fluorescein-guided endoscopic transtubular surgery for the resection of IV-PVMTs.

METHODS

Twenty patients with IV-PVMTs underwent FG endoscopic transtubular tumor resection. Fluorescein sodium was administered before the dural opening. The intraoperative fluorescence staining was classified as "helpful" and "unhelpful" based on surgical observation. Extent of resection was assessed using postoperative magnetic resonance imaging. Karnofsky Performance Status (KPS) score was used to evaluate the general physical condition of patients.

RESULTS

There were 9 glioblastomas, 4 anaplastic astrocytomas and 7 metastatic tumors. "Helpful" fluorescence staining was observed in 16(80%) of 20 patients. Gross total resection was achieved in 16(80%) cases, near-total in 3(15%) cases, and subtotal in 1 (5%) case. No intra- or postoperative complications related to the fluorescein sodium occurred. The median preoperative KPS score was 83, and the median KPS score 3-month after surgery was 88.

CONCLUSION

FG endoscopic transtubular surgery is a feasible technique for the resection of IV-PVMTs. It may be a safe and effective option for patients with these tumors. Future prospective randomized studies with larger samples are needed to confirm these preliminary data.

A new simple and free tubular device for microscopic transcortical approach to deep-seated lesions: technical note and case example

BACKGROUND

Surgery for deep-seated brain tumors remains challenging. Transcortical approaches often require brain retraction to ensure an adequate surgical corridor, thus possibly leading to brain damage. Various techniques have been developed to minimize brain retraction such as self-retaining retractors, endoscopic approaches, or tubular retractor systems. Even if they evenly distribute the mechanical pressure over the parenchyma, rigid retractors can also cause some degree of brain damage and have significant disadvantages. We propose here a soft cottonoid retractor for microscopic resection of deep-seated and ventricular lesions.

METHODS

Through a small corticectomy, a channel route with a blunt cannula is developed until the lesion is reached. Then, a "balloon-like system" made with a surgical glove is progressively inflated, dilatating the surgical corridor. A mini-tubular device, handmade by suturing a surgical cottonoid, is positioned into the corridor, unfolded, and sutured to the edge of the dura, to prevent it from being progressively expelled from the working channel. This allows a good visualization of the lesion and surrounding structures under the microscope.

RESULTS

Advantages of this technique are the softness of the tube walls, the absence of rigid arm to hold the tube, and the possibility for the tube to follow the movements of the instruments and to modify its orientation according to the working area.

CONCLUSION

This simple and inexpensive tubular working channel for microscopic transcortical approach is a valuable alternative technique to traditional self-retaining retractor and rigid tube for the microsurgical resection of deep-seated brain tumors.

Surgery for Coagulopathy-Related Intracerebral Hemorrhage: Craniotomy vs. Minimally Invasive Neurosurgery

Coagulopathy-related intracerebral hemorrhage (ICH) is life-threatening. Recent studies have shown promising results with minimally invasive neurosurgery (MIN) in the reduction of mortality and improvement of functional outcomes, but no published data have recorded the safety and efficacy of MIN for coagulopathy-related ICH. Seventy-five coagulopathy-related ICH patients were retrospectively reviewed to compare the surgical outcomes between craniotomy (n = 52) and MIN (n = 23). Postoperative rebleeding rates, morbidity rates, and mortality at 1 month were analyzed. Postoperative Glasgow Outcome Scale Extended (GOSE) and modified Rankin Scale (mRS) scores at 1 year were assessed for functional outcomes. Morbidity, mortality, and rebleeding rates were all lower in the MIN group than the craniotomy group (8.70% vs. 30.77%, 8.70% vs. 19.23%, and 4.35% vs. 23.08%, respectively). The 1-year GOSE score was significantly higher in the MIN group than the craniotomy group (3.96 ± 1.55 vs. 3.10 ± 1.59, p = 0.027). Multivariable logistic regression analysis also revealed that MIN contributed to improved GOSE (estimate: 0.99650, p = 0.0148) and mRS scores (estimate: -0.72849, p = 0.0427) at 1 year. MIN, with low complication rates and improved long-term functional outcome, is feasible and favorable for coagulopathy-related ICH. This promising result should be validated in a large-scale prospective study.

Minimally-invasive tubular retraction ports for intracranial neurosurgery: History and future perspectives

Brain retraction is a necessary yet potentially damaging requirement of accessing lesions located in deep structures. The development of minimally-invasive tubular retractors (MITRs) provides the theoretical advantage of maximizing visualization of and access to deep-seated lesions, all while minimizing collateral tissue damage. These advantages make MITRs preferable to traditional bladed retractors in the majority of deep-seated lesions. Several commercially-available MITR systems currently exist and have been shown to aid in achieving excellent outcomes with acceptable safety profiles. Nevertheless, important drawbacks to currently-available MITR systems exist. Continued pursuit of an ideal MITR system that provides maximal visualization and access to deep-seated lesions while minimizing retraction-related tissue damage is therefore important. In this review, we discuss the historical development of MITRs, the advantages of MITRs compared to traditional bladed retractors, and opportunities to improve the development of prospective MITRs.

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.

Fluorescein Sodium-Guided Neuroendoscopic Resection of Deep-Seated Malignant Brain Tumors: Preliminary Results of 18 Patients

BACKGROUND

Deep-seated intracranial lesions are challenging to resect completely and safely. Fluorescence-guided surgery (FGS) promotes the resection of malignant brain tumors (MBTs). Classically, FGS is performed using microscope equipped with a special filter. Fluorescence-guided neuroendoscopic resection of deep-seated brain tumors has not been reported yet.

OBJECTIVE

To evaluate the feasibility, safety, and effectiveness of the fluorescence-guided neuroendoscopic surgery in deep-seated MBTs.

METHODS

A total of 18 patients with high-grade glioma (HGG) and metastatic tumor (MT) underwent fluorescein sodium (FS)-guided neuroendoscopic surgery. Tumor removal was carried out using bimanual microsurgical techniques under endoscopic view. The degree of fluorescence staining was classified as "helpful" and "unhelpful" based on surgical observation. Extent of resection was determined using magnetic resonance imaging (MRI). Karnofsky Performance Status (KPS) score was used for evaluation of general physical performances of patients.

RESULTS

A total of 11 patients had HGG, and 7 had MT. No technical difficulty was encountered regarding the use of endoscopic technique. "Helpful" fluorescence staining was observed in 16 patients and fluorescent tissue was completely removed. Postoperative MRI confirmed gross total resection (88.9%). In 2 patients, FS enhancement was not helpful enough for tumor demarcation and postoperative MRI revealed near total resection (11.1%). No complication, adverse events, or side effects were encountered regarding the use of FS. KPS score of patients was improved at 3-mo follow-up.

CONCLUSION

FS-guided endoscopic resection is a feasible technique for deep-seated MBTs. It is safe, effective, and allows for a high rate of resection. Future prospective randomized studies are needed to confirm these preliminary data.

Correlation between intraoperative serum lactate and new-onset postoperative neurodeficits in patients undergoing elective craniotomies

Background:

Aims:

Study Design:

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Transcortical Approach to Deep-Seated Intraventricular and Intra-axial Tumors Using a Tubular Retractor System: A Technical Note and Review of the Literature

BACKGROUND

 Retraction of white matter overlying a brain lesion can be difficult without causing significant trauma especially when using traditional methods of bladed retractors. These conventional retractors can produce regions of focal pressure resulting in contusions and areas of infarct.

METHODS

 In this article, we present a retrospective case series of six patients with deep-seated intraventricular and intra-axial tumors that were approached using a ViewSite Brain Access System (tubular retractor). The authors describe a unique method of creating a pathway using a dilated glove. We shall also review the relevant literature that reports this type of surgery. Cases included three cases with third ventricular colloid cysts, one case of a third ventricular arachnoid cyst, one case with a lateral ventricular neurocytoma, and a case with a deeply seated intra-axial metastatic tumor.

RESULTS

 Gross total resection was achieved in five cases with small residual in the central neurocytoma operation, with no documented neurological deficit in any case. One case had persistent memory problems and one case had continuing decline from the metastatic disease.

CONCLUSION

 The introduction of tubular-shaped retractor systems has offered the advantage of reducing retraction pressures and distributing any remaining force in a more even and larger distributed area, thus reducing the risk of previous associated morbidity while also permitting great visualization of the target lesion.

An Illustrative Review of Common Modern Craniotomies

Craniotomy, or a surgical opening into the skull, has been observed as early as Paleolithic and Neolithic periods. Early craniotomies carried great morbidity and mortality and standardized during the 20th century, improving surgical outcomes. The simultaneous evolution of medical imaging and stereotactic navigation systems has allowed imaging to correlate findings with surgical approaches, further optimizing patient safety. We review the history of craniotomy and provide an imaging review of the most common craniotomy approaches.

Biomechanical modelling and computer aided simulation of deep brain retraction in neurosurgery

BACKGROUND AND OBJECTIVES

Surgical simulators are widely used to promote faster and safer surgical training. They not only provide a platform for enhancing surgical skills but also minimize risks to the patient's safety, operation theatre usage, and financial expenditure. Retracting the soft brain tissue is an unavoidable procedure during any surgery to access the lesioned tissue deep within the brain. Excessive retraction often results in damaging the brain tissue, thus requiring advanced skills and prior training using virtual platforms. Such surgical simulation platforms require an anatomically correct computational model that can accurately predict the brain deformation in real-time.

METHODS

In this study, we present a 3D finite element brain model reconstructed from MRI dataset. The model incorporates precisely the anatomy and geometrical features of the canine brain. The brain model has been used to formulate and solve a quasi-static boundary value problem for brain deformation during brain retraction. The visco-hyperelastic framework within the theory of non-linear elasticity has been used to set up the boundary value problem. Consequently, the derived non-linear field equations have been solved using finite element solver ABAQUS.

RESULTS

The retraction simulations have been performed for two scenarios: retraction pressure in the brain and forces required to perform the surgery. The brain was retracted by 5 mm and retained at that position for 30 minutes, during which the retraction pressure attenuates to 36% of its peak value. Both the model predictions as well as experimental observations on canine brain indicate that brain retraction up to 30 minutes did not cause any significant risk of induced damage. Also, the peak retraction pressure level indicates that intermittent retraction is a safer procedure as compared to the continuous retraction, for the same extent of retraction.

CONCLUSIONS

The results of the present study indicate the potential of a visco-hyperelastic framework for simulating deep brain retraction effectively. The simulations were able to capture the dominant characteristics of brain tissue undergoing retraction. The developed platform could serve as a basis for the development of a detailed model in the future that can eventually be used for effective preoperative planning and training purposes.

Real-Time Intraoperative Pressure Monitoring to Avoid Surgically Induced Localized Brain Injury Using a Miniaturized Piezoresistive Pressure Sensor

Neurosurgical procedures often cause damage to the brain tissue at the periphery from surgical manipulations. Especially during retraction, a large amount of pressure could be applied on the brain surface, which can damage it, leading to brain herniation, which can be fatal for patients. To resolve this issue, we have developed a pressure sensor that can be used to monitor the applied pressure during surgery for intraoperative care. This device was tested on a rodent model to create a superficial surgically induced damage profile for three different applied pressures (30, 50, and 70 mmHg) and compared to a standard intracranial pressure monitoring system. Magnetic resonance imaging has been performed after surgical procedures to detect the herniation caused by applied pressure. To evaluate the damage to brain cells and tissue rupture, histological analysis was performed using hematoxylin and eosin staining. A scoring system was developed to understand the severity of the surgically induced brain injury, which will help neurosurgeons to limit the pressure to an optimum point without causing damage.

Intraoperative MRI-assisted neuro-port surgery for the resection of cerebral intraparenchymal cavernous malformation

Background

Intraparenchymal cerebral cavernous malformation is difficult to localize intraoperatively with conventional frameless navigation due to the “brain shift” effect. We conducted this study to evaluate the efficacy and safety of intraoperative magnetic resonance image (iMRI)-assisted neuro-port surgery for the resection of cerebral intraparenchymal cavernous malformation.

Methods

Between April 2016 and December 2017, 54 consecutive patients with intraparenchymal cerebral cavernous malformation who get surgical treatment in our hospital were enrolled into this study. Twenty-one patients were treated using iMRI-assisted neuro-port surgery (experiment group), and 33 patients underwent treatment by conventional microsurgery (control group). The iMRI was used in all cases for the compensation of the “brain shift” effect and keeping the navigation system up-to-date. The surgical resection rate, the total operation time, and the preoperative and postoperative Karnofsky Performance Status (KPS) scores were determined to evaluate the operative procedures.

Results

There were no significant differences between the two groups in mean age, gender ratio, and volume of lesions (P > 0.05). For the experiment group, the average duration of the procedure was 188.8 min with total resection of the lesions achieved in all 21 cases. For the control group, the average duration of the procedure was 238.2 min with total resection of the lesions achieved in 25 of 33 cases. The differences in the average duration of the procedure and the number of totally resected lesions between the two groups were statistically significant (P < 0.05). Regarding postoperative neurological function, postoperative KPS scores for the experiment group were significantly higher than those of the control group (P = 0.018).

Conclusion

Our results show that iMRI-assisted neuro-port surgery is helpful for intraparenchymal cerebral cavernous malformation surgery. The method provides high accuracy and efficiency for lesion targeting and permits excellent anatomic orientation. With the assistance of iMRI technology, we achieved a higher resection rate and a lower incidence of postoperative neurological deficits. Additionally, iMRI is helpful for the compensation of the “brain shift” effect, and it can update the navigation system.

Electronic supplementary material

The online version of this article (10.1186/s41016-019-0171-x) contains supplementary material, which is available to authorized users.

Cottonoid Sliders: A Simple and Cost-Effective Tool for Retractorless Intracranial Surgery

BACKGROUND AND IMPORTANCE

Retraction injury can result in significant complications during intracranial operations. Alternative surgical techniques to minimize retraction pressure and duration of retraction can minimize the risk of retraction injury. We describe the use of a cottonoid "slider," which is a simple, cost-effective modification of a commonly used cottonoid, in multiple applications.

CLINICAL PRESENTATION

The cottonoid sliders are constructed preoperatively by overlaying an adhesive plastic incision drape on one side of a dry cottonoid patty and trimming the edges to fit the form of the cottonoid. Intraoperatively, the sliders can slide across the parenchymal surface atraumatically and are used for gentle retraction to expose desired areas. In addition, suction may be placed on the slider to clear fluid from the operative view. The plastic side of the slider prevents adherence to the parenchymal surface. Retractorless surgical techniques have been developed to minimize risk of retractor associated injury in intracranial surgery by reducing retraction pressure and duration. Given that the cottonoid sliders glide along the parenchyma, do not stick, and are used for dynamic retraction, the main objectives to minimize retraction injury can be met while not compromising operative efficiency.

CONCLUSION

Cottonoid sliders are a simple and cost-effective method of providing gentle exposure during intracranial surgery. This technique represents a valuable and cost-effective addition to the neurosurgical armamentarium.

Minimally Invasive Surgical Outcomes for Deep-Seated Brain Lesions Treated with Different Tubular Retraction Systems: A Systematic Review and Meta-Analysis

BACKGROUND

Minimally invasive surgery using tubular retractors was developed to minimize injury of surrounding brain during the removal of deep-seated lesions. No evidence supports the superiority of any available tubular retraction system in the treatment of these lesions. We conducted a systematic review and meta-analysis to evaluate outcomes and complications after the resection of deep-seated lesions with tubular retractors and among available systems.

METHODS

A PRISMA compliant systematic review was conducted on PubMed, Embase, and Scopus to identify studies in which tubular retractors were used to resect deep-seated brain lesions in patients ≥18 years old.

RESULTS

The search strategy yielded 687 articles. Thirteen articles complying with inclusion criteria and quality assessment were included in the meta-analysis. A total of 309 patients operated on between 2008 and 2018 were evaluated. The most common lesions were gliomas (n = 127), followed by metastases (n = 101) and meningiomas (n = 19). Four different tubular retractors were used: modified retractors (n = 121, 39.1%); METRx (n = 60, 19.4%); BrainPath (n = 92, 29.7%); and ViewSite Brain Access System (n = 36,11.7%). Estimated gross total resection rate was 75% (95% confidence interval, 69%-80%; I² = 9%), whereas the estimated complication rate was 9% (95% confidence interval: 6%-14%; I² = 0%). None of the different brain retraction systems was found to be superior regarding extent of resection or complications on multiple comparisons (P > 0.05).

CONCLUSIONS

Tubular retractors represent a promising tool to achieve maximum safe resection of deep-seated brain lesions. However, there does not seem to be a statistically significant difference in extent of resection or complication rates among tubular retraction systems.

Minimally invasive resection of intracranial lesions using tubular retractors: a large, multi-surgeon, multi-institutional series

PURPOSE

Lesions located in subcortical areas are difficult to safely access. Tubular retractors have been increasingly used successfully with low complication profile to access lesions by minimizing brain retraction trauma and distributing pressure radially. Both binocular operative microscope and monocular exoscope are utilized for lesion visualization through tubular retractors. We present the largest multi-surgeon, multi-institutional series to determine the efficacy and safety profile of a transcortical-transtubular approach for intracranial lesion resections with both microscopic and exoscopic visualization.

METHODS

We reviewed a multi-surgeon, multi-institutional case series including transcortical-transtubular resection of intracranial lesions using either BrainPath (NICO, Indianapolis, Indiana) or ViewSite Brain Access System (VBAS, Vycor Medical, Boca Raton, Florida) tubular retractors (n = 113).

RESULTS

One hundred thirteen transtubular resections for intracranial lesions were performed. Patients presented with a diverse number of pathologies including 25 cavernous hemangiomas (21.2%), 15 colloid cysts (13.3%), 26 GBM (23.0%), two meningiomas (1.8%), 27 metastases (23.9%), 9 gliomas (7.9%) and 9 other lesions (7.9%). Mean lesion depth below the cortical surface was 4.4 cm, and mean lesion size was 2.7 cm. A gross total resection was achieved in 81 (71.7%) cases. Permanent complication rate was 4.4%. One patient (0.8%) experienced one early postoperative seizure (< 1 week postop). No patients experienced late seizures (> 1 week follow-up). Mean post-operative hospitalization length was 4.1 days.

CONCLUSION

Tubular retractors provide a minimally invasive operative corridor for resection of intracranial lesions. They provide an effective tool in the neurosurgical armamentarium to resect subcortical lesions with a low complication profile.

Tumor retractor: a simple and novel instrument for brain tumor surgery

Background

It is important to secure a surgical space during brain tumor surgery. One of the commonly used methods is to retract the brain. We hypothesized that the tumor can be retracted and that the normal brain tissue retraction can be minimized during surgery, and thus, the degree of collateral damage caused by brain retraction would be reduced.

Methods

The tumor retractor had a 90°, hard, and sharp tip for fixation of the tumor. The distal part of the retractor has a malleable and thin blade structure. By adjusting the angle of the distal malleable part of the tumor retractor, the operator can make the retracting angle additionally. Retractors with thin blade can be used in a conventional self-retraction system. To pull and hold the tumor constantly, the tumor retractor is held by a self-retraction system. The surgical technique using a tumor retractor is as follows: The first step is to fix the retractor to the tumor. The second step is to pull the retractor in the operator’s desired direction by applying force. After the tumor is pulled by adjusting the degree of force and angle, the surgical arm should be held in place to maintain the tumor retracted state.

Results

The tumor retractor was used to minimize the brain retraction, pulling the tumor in the opposite direction from the surrounding brain tissue. In clinical cases, we can apply the tumor retractor with good surgical outcomes.

Conclusions

A tumor retractor can be used to pull a tumor and minimize the brain retraction.

[Brain tissue relaxation in craniotomy: a modern view of the perennial problem]

Intraoperative relaxation of brain tissue is one of the important factors affecting the quality and successful outcome of neurosurgical interventions. Despite many clinical studies on the problem of brain bulging, many issues remain not fully resolved. First of all, these are safety aspects of the preventive and therapeutic use of various strategies to fight this phenomenon, development of indications for introduction of hyperosmotic solutions, and use of hyperventilation or lifting of the head end of the operating table.