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

Exoscope aided trans-sulcal minimally invasive parafascicular resection of a paediatric brainstem pilocytic astrocytoma using a tubular retractor system

The surgical management of brainstem glioma is challenging and has significant morbidity. Advances in surgical armamentarium has presented the opportunity to tackle these lesions. We present the case of a paediatric patient with a 2.3cm midbrain pilocytic astrocytoma. With the aid of tractography, neuro-navigation, 3-dimensional exoscope and a tubular retractor, near total resection of the tumour was achieved through a trans-sulcal para-fascicular approach without permanent injury to the corticospinal tract. To our knowledge this is the first report of a brainstem tumour resected using this approach and demonstrates what can be achieved with synergistic utility of evolving technologies in neurosurgery.

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 craniotomy for putaminal hemorrhage using a tubular retractor: A technical note

Background

Minimally invasive endoscopic and stereotactic surgery have been established as surgical treatments for putaminal hemorrhage. However, facilities that do not have equipment for endoscopic or stereotactic surgery will likely have to perform conventional craniotomy. Using a tubular retractor, we were able to perform minimally invasive surgery, such as endoscopic surgery.

Methods

A craniotomy was performed for left putaminal hemorrhage after cerebral infarction treatment. A 3-4 cm craniotomy centered at Kocher's point was performed under general anesthesia. A 2 cm incision was made in the cortex, and a tubular retractor was inserted under a microscope. The hematoma was reached at a position 4-5 cm from the cortex.

Results

Thanks to the tubular retractor, it was relatively easy to observe the hematoma, and it was possible to remove it and confirm hemostasis without difficulty. Brain injury caused by the retractor insertion cavity was small, and no hemostasis was required. The surgery was completed by dura mater closure, bone flap fixation, and wound closure as per the standard. Most of the putaminal hemorrhage could be removed, and there was no rebleeding after the operation. The patient is still undergoing rehabilitation because of aphasia and muscle weakness. Manual Muscle Testing was at three points in the upper limb, and four points in the lower limb remained.

Conclusion

For putaminal hemorrhage, microscopic craniotomy was performed using a tubular retractor and an approach such as endoscopic surgery. Craniotomy, hematoma removal, and hemostasis operations are also considered to be minimally invasive surgeries.

Cylinder tumor surgery in pediatric low-grade gliomas

BACKGROUND

Periventricular pediatric low-grade gliomas (pLGG) present a surgical challenge due to their deep-seated location, accessibility, and relationship with the subcortical network connections. Minimally invasive parafascicular approaches with tubular brain retractors (port brain surgery) have emerged, in recent years, as an alternative to conventional microsurgical and endoscopic approaches for removal of periventricular tumors.

OBJECTIVES

To describe the minimally invasive approach with tubular brain retractors for periventricular pLGG, its technique, applications, safety, and efficacy.

METHODS

In this article, we describe the port brain surgery techniques for periventricular pLGG as performed in different centers, with different commercialized tubular retractor systems. Illustrative cases followed by a literature review are analyzed, with a detailed description of different approaches or techniques, comparing their advantages and disadvantages with contemporary microsurgical and endoscopic approaches.

CONCLUSIONS

The port brain surgery with micro-exoscopic vision and endoscopic assistance, for the treatment of deep-seated lesions such as periventricular pLGG, is an alternative for achieving a functionally safe-gross total or subtotal-tumor resection, obtaining adequate tissue for pathological examination. This technique could offer a new dimension for a less-invasive, safe, and effective access to deep-seated tumors, offering the possibility to lower morbidity in experienced hands.

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.

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.

Surgical cytoreduction of deep-seated high-grade glioma through tubular retractor

OBJECTIVE

Maximal safe resection is the goal of surgical treatment for high-grade glioma (HGG). Deep-seated hemispheric gliomas present a surgical challenge due to safety concerns and previously were often considered inoperable. The authors hypothesized that use of tubular retractors would allow resection of deep-seated gliomas with an acceptable safety profile. The purpose of this study was to describe surgical outcomes and survival data after resection of deep-seated HGG with stereotactically placed tubular retractors, as well as to discuss the technical advances that enable such procedures.

METHODS

This is a retrospective review of 20 consecutive patients who underwent 22 resections of deep-seated hemispheric HGG with the Viewsite Brain Access System by a single surgeon. Patient demographics, survival, tumor characteristics, extent of resection (EOR), and neurological outcomes were recorded. Cannulation trajectories and planned resection volumes depended on the relative location of white matter tracts extracted from diffusion tractography. The surgical plans were designed on the Brainlab system and preoperatively visualized on the Surgical Theater virtual reality SNAP platform. Volumetric assessment of EOR was obtained on the Brainlab platform and confirmed by a board-certified neuroradiologist.

RESULTS

Twenty adult patients (18 with IDH-wild-type glioblastomas and 2 with IDH-mutant grade IV astrocytomas) and 22 surgeries were included in the study. The cohort included both newly diagnosed (n = 17; 77%) and recurrent (n = 5; 23%) tumors. Most tumors (64%) abutted the ventricular system. The average preoperative and postoperative tumor volumes measured 33.1 ± 5.3 cm3 and 15.2 ± 5.1 cm3, respectively. The median EOR was 93%. Surgical complications included 2 patients (10%) who developed entrapment of the temporal horn, necessitating placement of a ventriculoperitoneal shunt; 1 patient (5%) who suffered a wound infection and pulmonary embolus; and 1 patient (5%) who developed pneumonia. In 2 cases (9%) patients developed new permanent visual field deficits, and in 5 cases (23%) patients experienced worsening of preoperative deficits. Preoperative neurological or cognitive deficits remained the same in 9 cases (41%) and improved in 7 (32%). The median overall survival was 14.4 months in all patients (n = 20) and in the newly diagnosed IDH-wild-type glioblastoma group (n = 16).

CONCLUSIONS

Deep-seated HGGs, which are surgically challenging and frequently considered inoperable, are amenable to resection through tubular retractors, with an acceptable safety profile. Such cytoreductive surgery may allow these patients to experience an overall survival comparable to those with more superficial tumors.

Multifunctional nanocarriers for delivering siRNA and miRNA in glioblastoma therapy: advances in nanobiotechnology-based cancer therapy

Glioblastoma multiforme (GBM) is one of the most lethal cancer due to poor diagnosis and rapid resistance developed towards the drug. Genes associated to cancer-related overexpression of proteins, enzymes, and receptors can be suppressed using an RNA silencing technique. This assists in obtaining tumour targetability, resulting in less harm caused to the surrounding healthy cells. RNA interference (RNAi) has scientific basis for providing potential therapeutic applications in improving GBM treatment. However, the therapeutic application of RNAi is challenging due to its poor permeability across blood-brain barrier (BBB). Nanobiotechnology has evolved the use of nanocarriers such as liposomes, polymeric nanoparticles, gold nanoparticles, dendrimers, quantum dots and other nanostructures in encasing the RNAi entities like siRNA and miRNA. The review highlights the role of these carriers in encasing siRNA and miRNA and promising therapy in delivering them to the glioma cells.

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.

The Extent of Resection in Gliomas-Evidence-Based Recommendations on Methodological Aspects of Research Design

OBJECTIVE

Modern neurosurgery has established maximal safe resection as a cornerstone in the management of diffuse gliomas. Evaluation of the extent of resection (EOR), and its association with certain outcomes or interventions, heavily depends on an adequate methodology to draw strong conclusions. We aim to identify weaknesses and limitations that may threaten the internal validity and generalizability of studies involving the EOR in patients with glioma and to suggest methodological recommendations that may help mitigate these threats.

METHODS

A systematic search was performed by querying PubMed, Web of Science, and Scopus since inception to April 30, 2021 using PICOS/PRISMA guidelines. Articles were then screened to identify high-impact studies evaluating the EOR in patients diagnosed with diffuse gliomas in accordance with predefined criteria. We identify common weakness and limitations during the evaluation of the EOR in the selected studies and then delineate potential methodological recommendations for future endeavors dealing with the EOR.

RESULTS

We identified 31 high-impact studies and found several research design issues including inconsistencies regarding EOR terminology, measurement, data collection, analysis, and reporting. Although some of these issues were related to now outdated reporting standards, many were still present in recent publications and deserve attention in contemporary and future research.

CONCLUSIONS

There is a current need to focus more attention to the methodological aspects of glioma research. Methodological inconsistencies may introduce weaknesses into the internal validity of the studies and hamper comparative analysis of cohorts from different institutions. We hope our recommendations will eventually help develop stronger methodological designs in future research endeavors.

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.

The use of exoscope combined with tubular retractor system for minimally invasive transsulcal resection of an ventricular atrium atypical choroid plexus papilloma: Three-dimensional operative video

Background:

Choroid plexus papilloma represents 1–4% of pediatric brain tumors, mostly located in the ventricular atrium.[1] Intraventricular tumors represent a challenge due to the poor visualization of the surgical field and damage to surrounding structures.[2] Use of tubular retraction reduces cerebrovascular trauma to the surrounding parenchyma by distributing pressure uniformly, allowing less invasive corticotomy, and more stability on surgical corridors that allow the surgeon to use both hands and external visualization devices.[2-5]

Case Description:

We present the case of a 3-year-old boy with progressive headache, vomiting, and loss of control in the left hand for 3 months, with a history of ventricular shunt placement for acute obstructive hydrocephalus. The MRI revealed large lobulated lesion, which was hypointense on T1, hyperintense on T2, marked enhancement on T1 C+ (Gd) within the atrium of the right lateral ventricle, and spectroscopy with a peak of choline. Written consent for the use of photos and videos on this work was obtained from the patient’s mother. A high-definition two-dimensional exoscope (VITOM^® Karl Storz, Tuttlingen) was used during the surgical approach and throughout tumor removal, which was aided by ViewSite Brain Access System (VBAS^®; Vycor Medical Inc.).[3] We performed a transparietal minimally invasive transsulcal parafascicular approach through the Frazier point for direct access to the ventricular atrium. Histological examination confirmed atypical choroid plexus papilloma. Postoperative imaging shows no residual tumor. The postoperative course was satisfactory with improvement of the headache and control of the left hand, leading to discharge home 1 week after surgery.

Conclusion:

The tubular transparietal minimally invasive approach obviates the need for traditional approaches to the atrium. This technique is safe and effective for the treatment of intraventricular and periventricular lesions, thus making this challenging target in more accessible to neurosurgeons, avoiding structure damage and any associated morbidity or mortality.

Combined Endoscopic Transsphenoidal and Tubular Retractor-Assisted Transventricular Approach for Giant Pituitary Adenomas

BACKGROUND

Surgical resection remains the standard treatment for most giant pituitary adenomas (GPAs). The selected surgical approach for these complex lesions depends mainly on their extension. Single approaches may be limited in some cases presenting with invasion into multiple compartments, thereby limiting extent of resection.

METHODS

We report a series of patients with GPA operated on through a combined approach involving an endoscopic endonasal transsphenoidal approach and a tubular retractor-assisted transventricular approach, describing the technique, its indications, limitations, and outcomes. Baseline and postoperative clinical, functional, and morphologic variables were documented up until each patient's last follow-up visit.

RESULTS

Five patients harboring tumors extending into the third and lateral ventricles were included. Mean extent of resection was 94.6%. Mean follow-up was 39.4 months. One patient presented with a growth hormone-secreting GPA, who achieved remission after repeat resection during follow-up. There were no intraoperative complications, and 1 patient required reoperation for cerebrospinal fluid leak repair. One patient received adjuvant radiotherapy, and 3 patients remained stable requiring no additional treatment. All patients maintained an adequate postoperative functional status.

CONCLUSIONS

The combined approach herein described may be a safe and effective option for some patients with GPAs extending into the third and lateral ventricles. An adequate patient selection is mandatory to exploit the benefits of each individual approach.

Use of emerging technologies to enhance the treatment paradigm for spontaneous intraventricular hemorrhage

The presence of intraventricular hemorrhage (IVH) portends a worse prognosis in patients presenting with spontaneous intracerebral hemorrhage (ICH). Intraventricular hemorrhage increases the rates of hydrocephalus, ventriculitis, and long-term shunt dependence. Over the past decade, novel medical devices and protocols have emerged to directly treat IVH. Presently, we review new technological adaptations to treating intraventricular hemorrhage in an effort to focus further innovation in treating this morbid neurosurgical pathology. We summarize current and historical treatments as well as innovations in IVH including novel procedural techniques, use of the Integra Surgiscope, use of the Artemis evacuator, use of BrainPath, novel catheter technology, large bore external ventricular drains, the IRRAflow, the CerebroFlo, and the future directions of the field. Technology and medical devices for both surgical and nonsurgical methods are advancing the treatment of IVH. With many promising new technologies on the horizon, prospects for improved clinical care for IVH and its etiologies remain hopeful.

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.

Observation of the impact of the eight-step process combined with the four-track crossover quality control applied to patients with glioma surgery: a randomised trial

Background

At present, surgery is the main treatment for patients with glioma, but there are certain risks in the operation. The traction and stress reaction of related brain tissue during surgery can cause complications such as cerebral edema, which adversely affects the prognosis of patients. The purpose of the present study was to explore the effect of an eight-step process combined with four-track quality control applied to patients undergoing glioma surgery.

Methods

A total of 122 patients undergoing glioma surgery admitted to our hospital from March 2017 to March 2020 were selected and divided into two groups according to the random number table method, each with 61 cases. The control group underwent routine intervention after surgery and the observation group underwent an eight-step process combined with four-track cross-over quality control intervention after surgery. The postoperative rehabilitation effects, cancer-related fatigue, changes in quality of life, and the incidence of complications before and after intervention were compared between the two groups.

Results

The time of catheter removal, the time of first eating, the time of getting out of bed, and the length of hospital stay of the observation group were shorter than those of the control group (P<0.05). In the observation group cognitive fatigue, physical fatigue, and emotional fatigue scores were lower than those of the control group after intervention (P<0.05) and the quality-of-life scores of the observation group after intervention were higher than those of the control group (P<0.05). The total incidence of complications in the observation group was lower than that of the control group (P<0.05).

Conclusions

The eight-step process combined with four-track quality control applied to patients undergoing glioma surgery can reduce cancer-related fatigue, improve quality of life, reduce complications, and promote speedy recovery.

Nanoparticles for Stem Cell Therapy Bioengineering in Glioma

Gliomas are a dismal disease associated with poor survival and high morbidity. Current standard treatments have reached a therapeutic plateau even after combining maximal safe resection, radiation, and chemotherapy. In this setting, stem cells (SCs) have risen as a promising therapeutic armamentarium, given their intrinsic tumor homing as well as their natural or bioengineered antitumor properties. The interplay between stem cells and other therapeutic approaches such as nanoparticles holds the potential to synergize the advantages from the combined therapeutic strategies. Nanoparticles represent a broad spectrum of synthetic and natural biomaterials that have been proven effective in expanding diagnostic and therapeutic efforts, either used alone or in combination with immune, genetic, or cellular therapies. Stem cells have been bioengineered using these biomaterials to enhance their natural properties as well as to act as their vehicle when anticancer nanoparticles need to be delivered into the tumor microenvironment in a very precise manner. Here, we describe the recent developments of this new paradigm in the treatment of malignant gliomas.