Purely endoscopic resection of colloid cysts

Endoscopic trans-septal interforniceal approach for excision of colloid cysts of the third ventricle using the rotational technique

Colloid cysts of the third ventricle are benign intracranial lesions that account for 0.5 to 2% of all brain tumors and are even rarer in pediatric population. Dandy was the first to successfully excise a colloid cyst of the third ventricle via a transcortical transventricular approach in 1921. For several decades to follow, the transcortical transventricular and transcallosal microsurgical approaches remained the cornerstone of surgical management of these lesions. With time and refinements in endoscopic equipment and techniques, endoscopic resection of colloid cysts evolved into a currently well-established and appealing minimally invasive alternative to microsurgery. Endoscopic endochannel techniques for colloid cysts of the third ventricle may either be transforaminal or trans-septal interforniceal, depending on the pathoanatomical features of the colloid cyst and its relation to the juxtaposed anatomical structures. The endoscopic trans-septal interforniceal approach is required to access the rare subset of colloid cysts that extend superior to the roof of the third ventricle between the two fornices insinuating themselves between the leaflets of the septum pellucidum. In this article, the surgical technique of the endochannel endoscopic trans-septal interforniceal approach is elaborated upon. A representative case is presented along with an operative video.

Full-endoscopic removal of third ventricular colloid cysts: technique, results, and limitations

Introduction

Colloid cysts (CCs) are rare benign lesions that usually arise from the roof of the third ventricle. They may present with obstructive hydrocephalus and cause sudden death. Treatment options include ventriculoperitoneal shunting, cyst aspiration, and cyst resection microscopically or endoscopically. This study aims to report and discuss the full-endoscopic technique for removing colloid cysts.

Materials and methods

A 25°-angled neuroendoscope with an internal working channel diameter of 3.1 mm and a length of 122 mm is used. The authors described the technique of resecting a colloid cyst by a full-endoscopic procedure and evaluated the surgical, clinical, and radiological results.

Results

Twenty-one consecutive patients underwent an operation with a transfrontal full-endoscopic approach. The swiveling technique (grasping the cyst wall and rotational movements) was used for CC resection. Of these patients, 11 were female, and ten were male (mean age, 41 years). The most frequent initial symptom was a headache. The mean cyst diameter was 13.9 mm. Thirteen patients had hydrocephalus at admission, and one needed shunting after cyst resection. Seventeen patients (81%) underwent total resection; 3 (14%), subtotal resection; and 1 (5%), partial resection. There was no mortality; one patient had permanent hemiplegia, and one had meningitis. The mean follow-up period was 14 months.

Conclusion

Even though microscopic resection of cysts has been widely used as a gold standard, successful endoscopic removal has been described recently with lower complication rates. Applying angled endoscopy with different techniques is essential for total resection. Our study is the first case series to show the outcomes of the swiveling technique with low recurrence and complication rates.

On Natural History and Management of Colloid Cysts: Time to Rethink?

BACKGROUND

Colloid cysts, although benign, may occasionally cause obstructive hydrocephalus and sudden death. Reliable prognostic factors for symptomatic progression have been sought, with heterogenous results.

METHODS

We conducted a retrospective review of all cases of colloid cysts of the third ventricle managed at our center between 2009 and 2019. Clinical and neuroimaging characteristics were analyzed using logistic regression in relation to symptomatic status and hydrocephalus. The cutoff values for outcome prediction were calculated using the receiver operating characteristic curve analysis.

RESULTS

There were 82 patients with colloid cysts, of whom 60 were asymptomatic and 22 symptomatic. None of the asymptomatic patients experienced acute neurologic decline or hydrocephalus during follow-up, whereas half (n = 11) of the symptomatic patients presented with hydrocephalus, 8 of whom had acute hydrocephalus. We found 3 putative candidate risk factors for symptomatic colloid cysts: T1-weighted magnetic resonance imaging hyperintense/mixed signal appearance (P = 0.004), location in risk zone I (P = 0.007), and a volume >236.49 mm3 (P = 0.007). Cyst diameter and volume/foramen of Monro diameter ratios had a decreasing trend over time among asymptomatic patients, providing new insights into the natural history of the disease.

CONCLUSIONS

Only a few asymptomatic colloid cysts showed progression requiring surgery, with no acute deterioration or fatal events, whereas the rest remained stable over time, thus supporting a more conservative approach for this group of patients. Higher risk for developing symptomatic colloid cyst was defined by a risk score that included T1-weighted magnetic resonance imaging appearance, risk zone, and colloid cyst volume, aiding the detection of patients at risk of clinical deterioration.

Retrospective evaluation of endoscopic treatment in colloid cyst of the third ventricle

Introduction

Endoscopic methods have gained a well-established position in surgical treatment of colloid cysts of third ventricle. However, the possibility of total tumor removal with this method and the long-term effectiveness of treatment are being questioned.

Aim

Personal twenty years’ experience in treatment of third ventricle colloid cysts is presented on the basis of retrospective analysis.

Material and methods

The study group included 58 patients diagnosed by neuroimaging (head CT/MRI) with third ventricle colloid cyst. Post-hospital follow-up ranged from 18 to 42 months. Long-term follow-up head CT/MRI was performed in 39 patients.

Results

The colloid cyst was removed totally in 47 (81%) patients. In 11 cases, the colloid cyst’s wall was tightly adherent to the roof of the third ventricle, which limited the radicality of the procedure. Sixteen patients demonstrated memory impairments, 4 patients epilepsy and another 2 akinetic mutism in the direct postoperative course. One patient died as a result of complications unrelated to the procedure. The average hospitalization was 5 days. In the late period after surgery, remission of the most, previously, reported ailments and symptoms has been reported. Surgical treatment for hydrocephalus was needed in 7 patients. In 3 cases cyst recurrence was diagnosed which required reoperation.

Conclusions

The endoscopic methods allow the total removal of a third ventricle colloid cyst in most patients. Leaving a small coagulated fragment of the cyst rarely results in its recurrence. This method results in effective treatment with a low complications rate, shortens hospitalization time and brings the patient a high level of satisfaction with a quick recovery.

Surgical approaches for resection of third ventricle colloid cysts: meta-analysis

Although outcome studies and systematic reviews have been published on the surgical treatment of third ventricle colloid cysts (TVCC), there are no meta-analyses that compare the outcomes for various surgical approaches. This meta-analysis assesses the outcomes and complications for transcortical, transcallosal, and endoscopic surgical approaches used to excise TVCCs. A meta-analysis of surgically excised TVCCs was performed with an assessment of outcome for transcortical, transcallosal, and endoscopic approaches. A random-effects model analyzed the extent of surgical excision. The analysis included reports that compared at least two of these surgical approaches, for a total of 11 studies comprising a population of 301 patients. The transcortical approach was associated with a higher incidence of complete excision compared to the endoscopic approach (OR = 0.137, p = 0.041), with no significant differences observed between transcortical and transcallosal approaches, and between transcallosal and endoscopic approaches. Comparison between endoscopic and pooled microsurgical approaches was also insignificant (OR = 0.22, p = 1). The risk of motor weakness was increased with the transcortical approach compared to the endoscopic approach (OR = 6.10, p = 0.018). There were no significant differences between transcortical and transcallosal approaches regarding newly onset seizures, and no significant mortality differences between all three approaches. This study demonstrates that microsurgical approaches are associated with a greater extent of resection compared to endoscopic approaches; however, best results are likely achieved based on the surgeon's expertise, flexibility, and case review.

Mechatronic Design of a Two-Arm Concentric Tube Robot System for Rigid Neuroendoscopy

Open surgical approaches are still often employed in neurosurgery, despite the availability of neuroendoscopic approaches that reduce invasiveness. The challenge of maneuvering instruments at the tip of the endoscope makes neuroendoscopy demanding for the physician. The only way to aim tools passed through endoscope ports is to tilt the entire endoscope; but, tilting compresses brain tissue through which the endoscope passes and can damage it. Concentric tube robots can provide necessary dexterity without endoscope tilting, while passing through existing ports in the endoscope and carrying surgical tools in their inner lumen. In this paper we describe the mechatronic design of a new concentric tube robot that can deploy two concentric tube manipulators through a standard neuroendoscope. The robot uses a compact differential drive and features embedded motor control electronics and redundant position sensors for safety. In addition to the mechatronic design of this system, this paper contributes experimental validation in the context of colloid cyst removal, comparing our new robotic system to standard manual endoscopy in a brain phantom. The robotic approach essentially eliminated endoscope tilt during the procedure (17.09° for the manual approach vs. 1.16° for the robotic system). The robotic system also enables a single surgeon to perform the procedure - typically in a manual approach one surgeon aims the endoscope and another operates the tools delivered through its ports.

Transcortical Endoscopic Surgery for Intraventricular Lesions

To review recent advances in endoscopic techniques for treating intraventricular lesions via transcortical passage. Articles in PubMed published since 2000 were searched using the keywords ‘endoscopy,’ ‘endoscopic,’ and ‘neuroendoscopic.’ Of these articles, those describing intraventricular lesions were reviewed. Suprasellar arachnoid cysts (SACs) can be treated with ventriculo-cystostomy (VC) or ventriculo-cysto-cisternostomy (VCC). VCC showed better results compared to VC. Procedure type, fenestration size, stent placement, and aqueductal patency may affect SAC prognosis. Colloid cysts can be managed using a transforaminal approach (TA) or a transforaminal-transchoroidal approach (TTA). However, TTA may result in better exposure compared to TA. Intraventricular cysticercosis can be cured with an endoscopic procedure alone, but if pericystic inflammation and/or ependymal reaction are seen, third ventriculostomy may be recommended. Tumor biopsies have yielded successful diagnosis rates of up to 100%, but tumor location, total specimen size, endoscope type, and vigorous coagulation on the tumor surface may affect diagnostic accuracy. An ideal indication for tumor excision is a small tumor with friable consistency and little vascularity. Tumor size, composition, and vascularity may influence a complete resection. SACs and intraventricular cysticercosis can be treated successfully using endoscopic procedures. Endoscopic procedures may represent an alternative to surgical options for colloid cyst removal. Solid tumors can be safely biopsied using endoscopic techniques, but endoscopy for tumor resection still results in considerable challenges.

Conversion technique from neuroendoscopy to microsurgery in ventricular tumors: Technical note

BACKGROUND

Ventricular tumors represent a major neurosurgical challenge, making endoscopic approach an invaluable tool as it gained importance due to technological advances. Nevertheless, the method is not exempt of risk and limitations, sometimes requiring an open surgery. Thus, initial measurements must be adopted in order to simplify an eventual need for conversion to open craniotomy.

METHODS

Here, we describe a series of 6 patients with ventricular tumors approached by neuroendoscopy where the conversion to microsurgery turned out to be necessary. Patients' average age was 59.5 years (39-75 years). Average tumoral size was 17.8 mm (15-21 mm). There were 2 cases of lateral ventricle subependymoma and 4 cases of third ventricle colloid cysts. A standard surgical incision was performed in the coronal direction, allowing lateral expansion to 10 cm. Moreover, the endoscopic burr hole was enlarged to a 5 cm craniotomy. A small enlargement of the endoscopic cortical access was performed to gain a transcortical microsurgical corridor to the ventricular cavity. The need for conversion arose due to high consistency of the tumor (3 cases), technical problems (2 cases), and cortical collapse (1 case).

RESULTS

There was one case of cerebrospinal fluid fistula and infection and one case of transitory memory disturbance. In both the cases, we obtained a complete functional recovery. Clinical and radiological follow-up showed total tumor removal with no recurrences.

CONCLUSIONS

The technique herein described was easy to perform, promptly bypassed the endoscopic limitations, and gathered excellent surgical results. The possibility of adapting the method to other tumor locations may be considered.

Hydrocephalus caused by unilateral foramen of Monro obstruction: A review on terminology

Background:

Hydrocephalus caused by unilateral foramen of Monro (FM) obstruction has been referred to in literature by many different terminologies. Precise terminology describing hydrocephalus confined to just one lateral ventricle has a very important prognostic value and determines whether or not the patient can be shunt free after an endoscopic procedure.

Methods:

Aiming to define the best term for unilateral FM obstruction, 19 terms were employed on PubMed database (http://www.ncbi.nlm.nih.gov/pubmed) as quoted phrases.

Results:

A total of 194 articles were found. Four patterns of hydrocephalus were discriminated as a result of our research term query and were divided by types for didactic purpose. Type A - partial dilation of the lateral ventricle; Type B - pure unilateral obstruction of the FM; Type C - previously shunted patients with secondary obstruction of the FM; and Type D - asymmetric lateral ventricles with patent FM.

Conclusion:

In unilateral FM obstruction hydrocephalus, an in-depth review on terminology application is critical to avoid mistakes that may compromise comparisons among different series. This terminology review suggests that Type B hydrocephalus, i.e., the hydrocephalus confined to just one lateral ventricle with no other sites of cerebrospinal fluid circulation blockage, are best described by the terms unilateral hydrocephalus (UH) and monoventricular hydrocephalus, the first being by far the most popular. Type A hydrocephalus is best represented in the literature by the terms uniloculated hydrocephalus and loculated ventricle; Type C hydrocephalus by the terms isolated lateral ventricle and isolated UH; and Type D hydrocephalus by the term asymmetric hydrocephalus.

Is there room for stereotactic radiosurgery as an option for third ventricular colloid cysts in patients refusing surgery? A case report and some therapeutic considerations

BACKGROUND

Colloid cysts of the third ventricle are epithelium-lined mucus-filled cysts usually occurring in the anterosuperior third ventricle. They are benign, slow-growing lesions but with the risk of sudden death. Treatment alternatives for symptomatic cysts include stereotactic aspiration, microsurgical or endoscopic approaches, and shunts for hydrocephalus.

CASE DESCRIPTION

The current case describes a patient presenting with hydrocephalus and a colloid cyst. A ventriculoperitoneal shunt was placed as the patient refused a definitive surgical procedure for the removal of the cyst, and stereotactic radiosurgery was then performed.

CONCLUSIONS

Stereotactic radiosurgery may be a reasonable alternative with minimal risks in those patients harboring a third ventricle colloid cyst refusing a definitive surgical procedure for resection of the cyst.

Combination of Neuroendoscopic and Stereotactic Procedures for Total Resection of Colloid Cysts with Favorable Neurological and Cognitive Outcomes

BACKGROUND

Despite a wide range of surgical procedures, an unresolved debate remains regarding which attempt is optimal for the treatment of colloid cysts in the third ventricle. In this article, we present a new combination of stereotactic and endoscopic techniques.

METHODS

This prospective study includes 27 consecutive patients with symptomatic primary and recurrent colloid cysts. All cysts were removed via a neuroendoscope through a rostral transfrontal, transforaminal approach. The endoscope was supported by an additional cannula fixed in the stereotactic frame. Both tools were inserted into one lateral ventricle through two separate burr holes using stereotactic guidance.

RESULTS

The median operating time was 135 minutes. All cysts were removed completely, and no mortality or permanent complications related to surgery occurred. The mean time of observation was 43.5 months (range, 3-78 months), and no clinical or radiologic recurrences were observed. One patient with a history of an infected ventriculoperitoneal shunt did not improve after cyst removal, but improved after subsequent reimplantation of the shunt. In all other cases, symptoms resolved (67%) or decreased (30%). Cognitive functions improved or remained unchanged in all 10 elective cases examined neuropsychologically before and after surgery.

CONCLUSIONS

The techniques we describe for removal of colloid cysts are safe and effective, even for recurrent cases, and they provide 100% total resection, favorable cognitive outcomes, low risk of recurrence, and low risk of morbidity. The disadvantages of this method are a longer time for surgery and the need for more complex instrumentation compared with conventional endoscopic resection.

Intraoperative Conversion from Endoscopic to Open Transcortical-Transventricular Removal of Colloid Cysts as a Salvage Procedure

OBJECTIVE

 To describe the transcortical-transventricular as an intraoperative salvage procedure and its effect of operative time and outcome.

METHODS

 Thirty-three patients were included in the study. Twenty patients had an endoscopic operation, five had a transcortical-transventricular approach, and eight underwent an interhemispheric approach for resection. Based on common cyst location in the roof of the third ventricle, we propose a simple classification of surgical operative zones based on relationships defined by the anterior column of the fornix, the septal vein, and the medial atrial vein.

RESULTS

 Complete capsule removal was achieved in 35% of endoscopic operations, 100% of transcortical-transventricular operations, and 63% of the interhemispheric operations. Operative time was 176 minutes for endoscopic operations, whereas the operative time for cases that converted to the transcortical-transventricular approach was 190 minutes (p=0.39).

CONCLUSION

 A surgical-based classification of zones within the roof of the third ventricle that can be accessed with microsurgical techniques is proposed. Both endoscopic and microsurgical cyst aspiration and excision remain options. We believe that younger patients, patients with large cysts that fill the third ventricle, or those with recurrence after prior treatment would benefit from open transcortical excision as a safe and effective operative approach using modern image-guided systems. Consent was formally obtained or waived for all subjects present within this study.

Endoscopic approach to colloid cyst: what is the optimal entry point and trajectory?

Object

An optimal entry point and trajectory for endoscopic colloid cyst (ECC) resection helps to protect important neurovascular structures. There is a large discrepancy in the entry point and trajectory in the neuroendoscopic literature.

Methods

Trajectory views from MRI or CT scans used for cranial image guidance in 39 patients who had undergone ECC resection between July 2004 and July 2010 were retrospectively evaluated. A target point of the colloid cyst was extended out to the scalp through a trajectory carefully observed in a 3D model to ensure that important anatomical structures were not violated. The relation of the entry point to the midline and coronal sutures was established. Entry point and trajectory were correlated with the ventricular size.

Results

The optimal entry point was situated 42.3 ± 11.7 mm away from the sagittal suture, ranging from 19.1 to 66.9 mm (median 41.4 mm) and 46.9 ± 5.7 mm anterior to the coronal suture, ranging from 36.4 to 60.5 mm (median 45.9 mm). The distance from the entry point to the target on the colloid cyst varied from 56.5 to 78.0 mm, with a mean value of 67.9 ± 4.8 mm (median 68.5 mm). Approximately 90% of the optimal entry points are located 40–60 mm in front of the coronal suture, whereas their perpendicular distance from the midline ranges from 19.1 to 66.9 mm. The location of the “ideal” entry points changes laterally from the midline as the ventricles change in size.

Conclusions

The results suggest that the optimal entry for ECC excision be located at 42.3 ± 11.7 mm perpendicular to the midline, and 46.9 ± 5.7 mm anterior to the coronal suture, but also that this point differs with the size of the ventricles. Intraoperative stereotactic navigation should be considered for all ECC procedures whenever it is available. The entry point should be estimated from the patient's own preoperative imaging studies if intraoperative neuronavigation is not available. An estimated entry point of 4 cm perpendicular to the midline and 4.5 cm anterior to the coronal suture is an acceptable alternative that can be used in patients with ventriculomegaly.

Endoscopic resection of incidental colloid cysts

OBJECT

Incidental colloid cysts are frequently managed with surveillance imaging rather than surgical excision. This approach is born out of their purported indolent growth pattern and the surgical morbidity associated with microsurgical removal. The advent of endoscopic colloid cyst removal may offer renewed assessment of these patients who carry a risk of acute neurological deterioration. An evidence-based recommendation should weigh the risks of operative treatment. Thus far, there has been no concentrated assessment of cyst removal in patients with incidental colloid cysts. The major objective in this study was to define the risks associated with the endoscopic surgical removal of incidentally diagnosed colloid cysts.

METHODS

A retrospective review of the medical records was performed to search for patients evaluated for a colloid cyst between the years 1996 and 2012. Eighty-seven patients underwent colloid cyst resection, and 34 were managed with nonoperative surveillance imaging. Microsurgical resections, endoscopic resections of residual or recurrent colloid cysts, and cases with unknown preoperative symptomatic status were excluded from further analysis. Seventy-seven cases of primary endoscopic resections were identified. Twenty resections were performed in patients with an incidental diagnosis and 57 in symptomatic individuals. Presenting characteristics and surgical outcomes were compared between the incidental and symptomatic groups.

RESULTS

The mean age at surgery was 39.65 years for the incidental and 43.31 years for the symptomatic group (p = 0.36). The median maximal cyst diameter was 9.7 mm (range 3-31 mm) for the incidental and 12 mm (range 5-34 mm) for the symptomatic group. The mean frontal and occipital horn ratio was 0.3928 for the incidental and 0.4445 for the symptomatic group (p = 0.002). Total resection was achieved in 90% of the incidental and 82.3% of the symptomatic cases (p = 0.49). The median hospital stay was 1 day for incidental and 2 days for symptomatic cases (p = 0.006). There were no deaths. There was one case of aseptic meningitis in the incidental group. In the symptomatic group there were 3 complications: one patient with subjective memory impairment, one with transient short-term memory deterioration, and another with a superficial wound infection treated with operative debridement. Two patients from the symptomatic group needed a CSF diversion procedure, and no shunting was needed in the incidental group. There were two recurrences in the symptomatic group (78 and 133 months postoperatively) and none in the incidental group (p = 1).

CONCLUSIONS

Age and cyst diameter were not correlated with the absence or presence of symptoms in patients with a colloid cyst of the third ventricle. Operative results were highly favorable in both groups and did not reveal a higher risk of morbidity in the patient presenting with an incidental lesion. The results support endoscopic resection as a legitimate therapeutic option for patients with incidental colloid cysts. Generalization of the operative results should be cautiously made, since this is a limited series and the results may depend on the degree of neuroendoscopic experience.

Combined endoscopic transforaminal-transchoroidal approach for the treatment of third ventricle colloid cysts

Colloid cysts are histologically benign lesions whose primary goal of treatment should be complete resection to avoid recurrence and sudden death. Open surgery is traditionally considered the standard approach, but, recently, the endoscopic technique has been recognized as a viable and safe alternative to microsurgery. The endoscopic approach to colloid cysts of the third ventricle is usually performed through the foramen of Monro. However, this route does not provide adequate visualization of the cyst attachment on the tela choroidea. The combined endoscopic transforaminal-transchoroidal approach (ETTA), providing exposure of the entire cyst and a better visualization of the tela choroidea, could increase the chances of achieving a complete cyst resection. Between April 2005 and February 2011, 19 patients with symptomatic colloid cyst of the third ventricle underwent an endoscopic transfrontal-transforaminal approach. Five of these patients, harboring a cyst firmly adherent to the tela choroidea or attached to the middle/posterior roof of the third ventricle, required a combined ETTA. Postoperative MRI documented a gross-total resection in all 5 cases. There were no major complications and only 1 patient experienced a transient worsening of the memory deficit. To date, no cyst recurrence has been observed. An ETTA is a minimally invasive procedure that can allow for a safe and complete resection of third ventricle colloid cysts, even in cases in which the lesions are firmly attached to the tela choroidea or located in the middle/posterior roof of the third ventricle.

Neuroendoscopic resection of intraventricular tumors: a systematic outcomes analysis

Introduction. Though traditional microsurgical techniques are the gold standard for intraventricular tumor resection, the morbidity and invasiveness of microsurgical approaches to the ventricular system have galvanized interest in neuroendoscopic resection. We present a systematic review of the literature to provide a better understanding of the virtues and limitations of endoscopic tumor resection. Materials and Methods. 40 articles describing 668 endoscopic tumor resections were selected from the Pubmed database and reviewed. Results. Complete or near-complete resection was achieved in 75.0% of the patients. 9.9% of resected tumors recurred during the follow-up period, and procedure-related complications occurred in 20.8% of the procedures. Tumor size ≤ 2cm (P = 0.00146), the presence of a cystic tumor component (P < 0.0001), and the use of navigation or stereotactic tools during the procedure (P = 0.0003) were each independently associated with a greater likelihood of complete or near-complete tumor resection. Additionally, the complication rate was significantly higher for noncystic masses than for cystic ones (P < 0.0001). Discussion. Neuroendoscopic outcomes for intraventricular tumor resection are significantly better when performed on small, cystic tumors and when neural navigation or stereotaxy is used. Conclusion. Neuroendoscopic resection appears to be a safe and reliable treatment option for patients with intraventricular tumors of a particular morphology.

Full scope of options

OBJECTIVE

The purpose of Clinical Problem Solving articles is to present management challenges to give practicing neurosurgeons insight into how field leaders address these dilemmas. This illustration is accompanied by a brief review of the literature on the topic.

PRESENTATION

The case of a 16-year-old boy presenting with headaches is presented. The patient is found to have a typical colloid cyst at the foramen of Monro. Bilateral ventriculoperitoneal shunt placement had been performed as an initial treatment of the patient before presentation.

RESULTS

Surgeons experienced in open and endoscopic surgery discuss their individual approaches to colloid cysts, in the context of previous shunting, providing a varied perspective on the clinical challenges posed by these lesions.

CONCLUSION

Both open and endoscopic options remain viable for excision of a colloid cyst. Each has associated potential complications, as illustrated by the current case.

Hemorrhagic colloid cyst with intraventricular extension

Colloid cysts of the third ventricle presenting with acute obstructive hydrocephalus due to intracystic and intraventricular hemorrhage are extremely rare. The authors report a case of a 43-year-old man with a hemorrhagic colloid cyst that was treated using endoscopic surgery. A small colloid cyst of the third ventricle was initially diagnosed in the patient, and he was treated conservatively at that time. On admission to the authors' institution he presented with sudden headache onset without neurological deficits. Computed tomography and MRI demonstrated a round hemorrhagic mass lesion in the third ventricle with bilateral intraventricular hemorrhage. Endoscopic resection was performed using a flexible videoscope. Only partial removal of the cyst was performed because of a tough cyst wall with highly viscous, hemorrhagic cystic contents. Histological examination revealed a typical colloid cyst wall and hemorrhage mixed within a mucinous substance. Postoperative serial neuroimaging demonstrated a gradual reduction in the residual cyst size and normalization in the lateral ventricle size.

Unusual "double density" colloid cysts

Third ventricular tumors vary in etiology. Treatment and surgical approach usually depends on preoperative diagnosis. Colloid cysts are the most common tumors of the third ventricle and the occurrence of two colloid cysts in the ventricular system is rare. Here we present a patient with paired colloid cysts of the third and lateral ventricles that had different radiographic characteristics, and both of which were resected through a purely endoscopic approach. This is the third reported patient with dual or paired colloid cysts. It is the second report of a lateral and third ventricular cyst, and to our knowledge the first to be successfully managed with purely endoscopic techniques obviating the need for a craniotomy. This report illustrates the importance of a wide differential when investigating intraventricular lesions and provides another example of a purely endoscopic transcortical approach for the resection of colloid cyst.

Emerging technology in intracranial neuroendoscopy: application of the NICO Myriad

Improvement in fiber optics and imaging paved the way for tremendous advancements in neuroendoscopy. These advancements have led to increasingly widespread use of the endoscope in neurosurgical procedures, which in turn incited a technological revolution leading to new approaches, instruments, techniques, and a diverse armamentarium for the treatment of a variety of neurosurgical disorders. Soft-tissue removal is often a rate-limiting aspect to endoscopic procedures, especially when the soft tissue is dense or fibrous. The authors review a series of cases involving patients treated between August 2009 and October 2010 with a new device (the NICO Myriad), a non-heat-generating, oscillating, cutting, and tissue removal instrument that can be used through the working channel of the endoscope as well as in open neurosurgical procedures. They used this device in 14 purely endoscopic intracranial procedures and 1 endoscope-assisted keyhole craniotomy. They report that the device was easy to use and found that tissue resection was more efficient than with other available endoscopic instruments, especially in the resection of fibrotic tissue. There were no observed device-related complications. The authors discuss the technical aspects of using this device in endoscopic resection of pituitary tumors, craniopharyngiomas, and colloid cysts. They also demonstrate its use in hydrocephalus and intraventricular clot removal and discuss its potential use in other neurosurgical disorders.

Endoscopic minimally invasive neurosurgery: emerging techniques and expanding role through an extensive review of the literature and our own experience - part I: intraendoscopic neurosurgery

BACKGROUND/AIMS

Minimally invasive neurosurgery is a growing field, more so in recent decades. The modernization of tools, especially the endoscope, has allowed for critical improvements and crucial advancements in minimally invasive neurosurgery. The current classification scheme for endoscopic procedures needs to be updated to reflect these advancements.

METHODS

Although the field of neuroendoscopy is continually evolving, the terminologies utilized to describe endoscopic procedures reflect and favor its use as mostly an assisting device complementing the microscope. Even though the classification was adequate for its time, it has become inexact and therefore confusing. We therefore propose a new classification scheme that encompasses the growing independence of endoscopic minimally invasive neurosurgery (EMIN) as well as the changing landscape within EMIN procedures.

RESULTS

We have classified our EMIN procedures, since 2002, as either 'intraendoscopic' (IEN) or 'extraendoscopic' (XEN) in relation to the endoscope's axis. Exemplary cases of IEN and a review of the literature are presented as well.

CONCLUSION

Our proposed classification scheme for solely endoscopic procedures is presented. The role of the endoscope as an independent tool is clarified.

Minimally invasive neurosurgery for cerebrospinal fluid disorders

This article focuses on minimally invasive approaches used to address disorders of cerebrospinal fluid (CSF) circulation. The author covers the primary CSF disorders that are amenable to minimally invasive treatment, including aqueductal stenosis, fourth ventricular outlet obstruction (including Chiari malformation), isolated lateral ventricle, isolated fourth ventricle, multiloculated hydrocephalus, arachnoid cysts, and tumors that block CSF flow. General approaches to evaluating disorders of CSF circulation, including detailed imaging studies, are discussed. Approaches to minimally invasive management of such disorders are described in general, and for each specific entity. For each procedure, indications, surgical technique, and known outcomes are detailed. Specific complications as well as strategies for their avoidance and management are addressed. Lastly, future directions and the need for structured outcome studies are discussed.

Exciting new advances in neuro-oncology: the avenue to a cure for malignant glioma

Malignant gliomas are the most common and deadly brain tumors. Nevertheless, survival for patients with glioblastoma, the most aggressive glioma, although individually variable, has improved from an average of 10 months to 14 months after diagnosis in the last 5 years due to improvements in the standard of care. Radiotherapy has been of key importance to the treatment of these lesions for decades, and the ability to focus the beam and tailor it to the irregular contours of brain tumors and minimize the dose to nearby critical structures with intensity-modulated or image-guided techniques has improved greatly. Temozolomide, an alkylating agent with simple oral administration and a favorable toxicity profile, is used in conjunction with and after radiotherapy. Newer surgical techniques, such as fluorescence-guided resection and neuroendoscopic approaches, have become important in the management of malignant gliomas. Furthermore, new discoveries are being made in basic and translational research, which are likely to improve this situation further in the next 10 years. These include agents that block 1 or more of the disordered tumor proliferation signaling pathways, and that overcome resistance to already existing treatments. Targeted therapies such as antiangiogenic therapy with antivascular endothelial growth factor antibodies (bevacizumab) are finding their way into clinical practice. Large-scale research efforts are ongoing to provide a comprehensive understanding of all the genetic alterations and gene expression changes underlying glioma formation. These have already refined the classification of glioblastoma into 4 distinct molecular entities that may lead to different treatment regimens. The role of cancer stem-like cells is another area of active investigation. There is definite hope that by 2020, new cocktails of drugs will be available to target the key molecular pathways involved in gliomas and reduce their mortality and morbidity, a positive development for patients, their families, and medical professionals alike.

Subarachnoid dissemination of intraventricular tumors following simultaneous endoscopic biopsy and third ventriculostomy

OBJECT

Endoscopic biopsy with concomitant third ventriculostomy (ETV) is a well-established diagnostic and therapeutic maneuver in patients presenting with noncommunicating hydrocephalus resulting from a tumor of the pineal region or posterior third ventricle. Fenestration of the floor of the third ventricle theoretically provides a conduit for the subarachnoid dissemination of an intraventricular tumor. The aim of this study was to ascertain the rate of leptomeningeal dissemination following this surgical procedure.

METHODS

The authors conducted a review of all patients for whom an ETV and simultaneous endoscopic biopsy procedure or tumor resection had been performed at their institutions between 1995 and 2008. Patients were divided into high or low risk groups by leptomeningeal metastatic potential based on pathology. All available postoperative clinical and radiographic data, including MR imaging of the brain and spinal cord, as well as CSF sampling were evaluated when available. A review of the literature was then conducted to establish rates of distant leptomeningeal dissemination for comparative purposes.

RESULTS

Thirty-two patients satisfied the criteria for study inclusion. Pathology revealed that 22 had a high risk for leptomeningeal dissemination. New leptomeningeal disease (1 yolk sac tumor and 1 pineoblastoma) occurred in 2 patients. The median clinical and brain MR imaging follow-ups overall were 34 (range 2-103 months) and 38 months (range 1-94 months), respectively. Follow-up MR imaging of the spine was performed in 12 patients (median 7 months postoperation), and CSF was analyzed in 15 patients (median 1 month postoperation). A Kaplan-Meier survival analysis predicted a 2-year metastasis-free survival of 94.7% for high-risk patients. Baseline rates of dissemination when ETV was not performed were in general between 8 and 24% for various high-risk pathologies according to a literature review.

CONCLUSIONS

The rate of leptomeningeal metastasis of tumors in this biopsy and ETV study was not increased when compared with rates from large series in the literature.