Endoscopic resection of incidental 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.

Endoscopic versus open microsurgery for colloid cysts of the third ventricle

PURPOSE

The surgical approach for colloid cysts of the third ventricle mainly consists of endoscopic or microscopic approach but few studies compare the neurologic outcomes and complications related to the different approaches. We retrospectively reviewed our results after resection of colloid cysts of the third ventricle using endoscopic surgery (ES) compared to open microsurgery (OS).

METHODS

Fifty-one patients were included in the study of which 17 patients underwent ES. Colloid cyst size and Evans' index were evaluated on CT or MRI scans. Presenting symptoms, neurologic outcomes and complications were compared between the two groups and analysed using Fisher's exact test. Operative time and days of hospital stay were compared between the two groups, using independent sample t-test. The median follow-up time was 96 days and did not differ significantly between the groups.

RESULTS

Shorter mean operative time (p = 0.04) and fewer days of hospital stay (p < 0.01) were found in the endoscopic group compared to the open microsurgical group. Presenting symptoms, neurological outcomes and postoperative complications were similar in the two groups.

CONCLUSIONS

ES showed similar neurologic outcomes and complications compared to OS for colloid cysts of the third ventricle. ES showed significantly shorter operative times and hospital stays compared to OS.

Surgical management of colloid cysts of the third ventricle: a single-institution comparison of endoscopic and microsurgical resection

OBJECTIVE

Colloid cysts of the third ventricle are histologically benign lesions that can cause obstructive hydrocephalus and death. Historically, colloid cysts have been removed by open microsurgical approaches. More recently, minimally invasive endoscopic and port-based techniques have offered decreased complications and length of stay, with improved patient satisfaction.

METHODS

A single-center retrospective analysis of patients with colloid cysts who underwent surgery at a large tertiary care hospital was performed. The cohort was assessed based on the surgical approach, comparing endoscopic resection to open microsurgical resection. The primary endpoint was rate of perioperative complications. Univariate analysis was used to assess several procedure-related variables and the cost of treatment. Multivariate analysis was used to assess predictors of perioperative complications. Total inpatient cost for each case was extracted from the health system financial database.

RESULTS

The study included 78 patients with colloid cysts who underwent resection either via an endoscopic approach (n = 33) or through a craniotomy (n = 45) with an interhemispheric-transcallosal or transcortical-transventricular approach. Nearly all patients were symptomatic, and half had obstructive hydrocephalus. Endoscopic resection was associated with reduced operative time (3.2 vs 4.9 hours, p < 0.001); lower complication rate (6.1% vs 33.1%, p = 0.009); reduced length of stay (4.1 vs 8.9 days, p < 0.001); and improved discharge to home (100% vs 75.6%, p = 0.008) compared to microsurgical resection. Coagulated residual cyst wall remnants were more common after endoscopic resection (63.6% vs 19.0%, p < 0.001) although this was not associated with a significantly increased rate of reoperation for recurrence. The mean follow-up was longer in the microsurgical resection group (3.1 vs 4.9 years, p = 0.016). The total inpatient cost of endoscopic resection was, on average, one-half (47%) that of microsurgical resection. When complications were encountered, the total inpatient cost of microsurgical resection was 4 times greater than that of endoscopic resection where no major complications were observed. The increased cost-effectiveness of endoscopic resection remained during reoperation.

CONCLUSIONS

Endoscopic resection of colloid cysts of the third ventricle offers a significant reduction in perioperative complications when compared to microsurgical resection. Endoscopic resection optimizes nearly all procedure-related variables compared to microsurgical resection, and reduces total inpatient cost by > 50%. However, endoscopic resection is associated with a significantly increased likelihood of residual coagulated cyst wall remnants that could increase the rate of reoperation for recurrence. Taken together, endoscopic resection represents a safe and effective minimally invasive approach for removal of colloid cysts.

Transseptal interforniceal endoscopic removal of superiorly recessed colloid cysts

OBJECTIVE

Transforaminal endoscopic colloid cyst resection is well described. However, some anatomical colloid cyst variants may warrant a modified approach. Rarely, colloid cysts separate the forniceal columns and grow superiorly within the leaflets of the septum pellucidum. Thus, the authors' goal was to characterize the imaging features, clinical presentation, surgical strategy, and outcomes of patients with this superiorly recessed colloid cyst variant.

METHODS

A retrospective evaluation of patients who underwent endoscopic resection of colloid cysts from 1999 to 2020 was performed. The patients were dichotomized depending on whether the cyst was located predominately below the forniceal columns or was superiorly recessed (forniceal column separation with variable intraseptal extension). This comparative cohort study focused on clinical presentation, imaging features, operative technique, and patient outcome.

RESULTS

In total, 182 patients were identified. Seventeen patients had colloid cysts that were defined as superiorly recessed and underwent transseptal interforniceal removal, and 165 patients underwent a standard transforaminal approach. Patients had similar demographic characteristics. However, transseptal cysts were on average larger (17.8 mm vs 11.4 mm, p < 0.0001), and these patients had a greater frontal-occipital horn ratio (0.45 vs 0.41, p = 0.012). They were also more likely to have undergone a previous resection (p = 0.02). The two cohorts had similar surgical outcomes, with no differences in extent of resection, recurrence, or complications.

CONCLUSIONS

Superiorly recessed intraseptal colloid cysts are larger and tend to splay the bodies of the fornix, thus requiring a parasagittal transseptal interforniceal endoscopic approach. This achieves complete removal with comparatively negligible morbidity or rare recurrence (5.9%).

Pediatric colloid cysts: a multinational, multicenter study. An IFNE-ISPN-ESPN collaboration

OBJECTIVE

Colloid cysts (CCs) are rare at all ages, and particularly among children. The current literature on pediatric CC is limited, and often included in mixed adult/pediatric series. The goal of this multinational, multicenter study was to combine forces among centers and investigate the clinical course of pediatric CCs.

METHODS

A multinational, multicenter retrospective study was performed to attain a large sample size, focusing on CC diagnosis in patients younger than 18 years of age. Collected data included clinical presentation, radiological characteristics, treatment, and outcome.

RESULTS

One hundred thirty-four children with CCs were included. Patient age at diagnosis ranged from 2.4 to 18 years (mean 12.8 ± 3.4 years, median 13.2 years, interquartile range 10.3-15.4 years; 22% were < 10 years of age). Twenty-two cases (16%) were diagnosed incidentally, including 48% of those younger than 10 years of age. Most of the other patients had symptoms related to increased intracranial pressure and hydrocephalus. The average follow-up duration for the entire group was 49.5 ± 45.8 months. Fifty-nine patients were initially followed, of whom 28 were eventually operated on at a mean of 19 ± 32 months later due to cyst growth, increasing hydrocephalus, and/or new symptoms. There was a clear correlation between larger cysts and symptomatology, acuteness of symptoms, hydrocephalus, and need for surgery. Older age was also associated with the need for surgery. One hundred three children (77%) underwent cyst resection, 60% using a purely endoscopic approach. There was 1 death related to acute hydrocephalus at presentation. Ten percent of operated patients had some form of complication, and 7.7% of operated cases required a shunt at some point during follow-up. Functional outcome was good; however, the need for immediate surgery was associated with educational limitations. Twenty operated cases (20%) experienced a recurrence of their CC at a mean of 38 ± 46 months after the primary surgery. The CC recurrence rate was 24% following endoscopic resection and 15% following open resections (p = 0.28).

CONCLUSIONS

CCs may present in all pediatric age groups, although most that are symptomatic present after the age of 10 years. Incidentally discovered cysts should be closely followed, as many may grow, leading to hydrocephalus and other new symptoms. Presentation of CC may be acute and may cause life-threatening conditions related to hydrocephalus, necessitating urgent treatment. The outcome of treated children with CCs is favorable.

Colloid cysts of the third ventricle in children

OBJECTIVE

The rarity of colloid cysts in children makes it difficult to characterize this entity and offer meaningful advice on treatment. Infrequent case reports exist, but to date there has been no age-specific assessment. The purpose of this study was to define any differences between children and adults who are evaluated and treated for colloid cysts of the third ventricle.

METHODS

Patients with colloid cysts were reviewed and stratified by age. Individuals ≤ 18 years of age were defined as pediatric patients and those > 18 years of age as adults. Clinical and radiographic data, treatment, and postoperative outcomes were compared between both groups. Bivariate analysis was conducted using the Fisher exact test for categorical variables and Mann-Whitney U-test for continuous variables.

RESULTS

Of 132 endoscopic resections (121 primary, 10 secondary, and 1 tertiary) of a colloid cyst, 9 (6.8%) were performed in pediatric patients (mean age 14.1 years, range 9-18 years) and 123 (93.2%) were performed in adult patients (mean age 43.8 years, range 19-73 years). Cases were found incidentally more commonly in pediatric than adult patients (66.7% vs 37.4%, p > 0.05), and pediatric patients had lower rates of hydrocephalus than adult patients (11.1% vs 63.4%, p < 0.05). Acute decompensation at presentation was found in 8 adults (6.5%) but no children. Complete cyst removal (88.9% vs 90.2%, p > 0.05) and length of stay (1.6 days vs 2.9 days, p > 0.05) were not significantly different between the groups. Postoperative complications (6.5% in adults, 0% in children) and recurrence (2.4% in adults, 0% in children) were rare in both groups, and there were no treatment-related deaths. The mean postoperative radiological follow-up was longer in pediatric patients (45 months, range 4-89 months) than adults (44.1 months, range 1-171 months).

CONCLUSIONS

While differences exist between children and adults regarding colloid cyst presentation, these are in keeping with the predicted evolution of a slow-growing lesion. Consistent with this observation, children had lower rates of hydrocephalus and a smaller mean maximal cyst diameter. Contrary to the published literature, however, sudden deterioration was not observed in pediatric patients but occurred in adult patients. In this limited pediatric sample size, the authors have not recorded any postoperative complications or recurrences to date. These encouraging results with endoscopic removal may positively impact future decisions related to children given their protracted life expectancy and projected rates of progression.

Endoscopic bimanual sharp dissection technique for gross-total resection of colloid cysts: technical note

Neuroendoscopic resection of colloid cysts has gained tremendous popularity over the last 2 decades because of good clinical outcomes and a low complication profile. However, in comparison to microsurgical resections, endoscopic resection has a lower rate of gross-total resection, which leaves the patient at risk for cyst recurrence. At present, there is still ongoing debate as to the best surgical approach for colloid cysts. Endoscopic resection as a technique has to compete with the good outcomes of microsurgical resections with respect to a long-term recurrence-free outcome. It is the authors' belief that gross-total resection should be the aim of endoscopic cyst resection. In this technical note, they describe their surgical technique for achieving safe gross-total resection of colloid cysts by using a ventriculoscopic system. The surgical technique includes a far anterolateral entry point, navigational guidance, bimanual sharp dissection, use of the endoscopic sheath as a retractor, the small-chamber irrigation technique, and the dry-field technique for hemostasis.

Neurocognitive Complications after Ventricular Neuroendoscopy: A Systematic Review

In recent years, neuroendoscopic treatment of hydrocephalus and various ventricular pathologies has become increasingly popular. It is considered by many as the first-choice treatment for the majority of these cases. However, neurocognitive complications following ventricular neuroendoscopic procedures may occur leading mostly to amnesia, which might have a grave effect on the patient's quality of life. Studies assessing neurocognitive complications after ventricular neuroendoscopic procedures are sparse. Therefore, we conducted a systematic review assessing the available literature of neurocognitive complications and outcome after ventricular neuroendoscopy. Of 1216 articles screened, 46 were included in this systematic review. Transient and permanent neurocognitive complications in 2804 ventricular neuroendoscopic procedures occurred in 2.0% (n = 55) and 1.04% (n = 28) of the patients, respectively. Most complications described are memory impairment, followed by psychiatric symptoms (psychosyndrome), cognitive impairment not further specified, declined executive function, and confusion. However, only in 20% of the series describing neurocognitive complications or outcome (n = 40) was neurocognition assessed by a trained neuropsychologist in a systematic manner. While in most of these series only a part of the included patients underwent neuropsychological testing, neurocognitive assessment was seldom done pre- and postoperatively, long-term follow up was rare, and patient's cohorts were small. A paucity of studies analyzing neurocognitive complications and outcome, through systematic neuropsychological testing, and the correlation with intraoperative lesions of neuronal structures (e.g., fornix) exists in the literature. Therefore, the neurocognitive and emotional morbidity after ventricular neuroendoscopic procedures might be underestimated and warrants further research.

Long-Term Outcomes of Endoscopic Third Ventricle Colloid Cyst Resection: Case Series With a Proposed Grading System

BACKGROUND

Endoscopic resection of colloid cysts has gained recent widespread practice. However, reported complication and recurrence rates are variable, possibly, in part, because of a lack of consistency with reporting of the extent of cyst capsule removal.

OBJECTIVE

To present the long-term outcomes of endoscopic resection of third ventricle colloid cysts without complete capsule removal and propose a grading system to allow consistent description of surgical outcomes.

METHODS

A retrospective review of 74 patients who underwent endoscopic resection of symptomatic third ventricle colloid cysts between 1995 and 2018 was performed. Kaplan-Meier analyses were used to assess recurrence-free survival rates.

RESULTS

Median patient age and cyst diameter were 48.0 (13.0-80.0) yr and 12.0 (5.0-27.0) mm, respectively. Complete emptying of cyst contents with capsule coagulation was achieved in 73 (98.6%) patients. All patients improved or remained stable postoperatively, with a median follow-up duration of 10.3 (0.3-23.7) yr. Radiographic recurrence occurred in 6 (8.1%) patients after their initial surgery, 5 (6.8%) of whom underwent redo endoscopic resection. No major complications or mortality was encountered at primary or recurrence surgery.

CONCLUSION

Endoscopic resection of third ventricle colloid cysts without emphasizing complete capsule removal is a viable option for successfully treating colloid cysts of the third ventricle. Long-term follow-up demonstrates that it is associated with low risks of complications, morbidity, mortality, and recurrence. The proposed extent of the resection grading scheme will permit comparison between the different surgical approaches and facilitate the establishment of treatment guidelines for colloid cysts.

Inchoate guidelines of endoscopic resection of colloid cysts

Colloid cyst are cystic lesions in the third ventricle and could render patients asymptomatic. However, there is an inherent risk of symptomatic progression, acute decompensation, and sudden death. Therefore, there is no clear consensus as how to observe or when to treat a newly diagnosed patient with a colloid cyst. The authors' objective is to identify the risk factors and then develop a risk stratification score to guide neurosurgeons during acute or chronic presentation. Radiological imaging characteristics have been outlined for the risk stratification as well preoperative evaluation. A baseline neuropsychological evaluation is helpful to obtain during an incidental presentation because history and neurological examination could be inconclusive in these cases. Radiological imaging with an MRI brain scan plays a vital role for the initial screening (determination of the cyst size, exact location, and the imaging characteristics) as well as for the preoperative planning. Stereotactic guidance is a high yield, followed by neuroendoscopic resection of the colloid cyst has been an established approach to resect these lesions. Modified colloid cyst risk scoring (mCCRS) system is robust and detailed for the optimal risk stratification of colloid cyst presentation. Stereotactic guided neuroendoscopic resection of the colloid cyst is a safe and efficacious approach to manage these lesions. The intended use, crucial steps involved, and the limitations of the technique have been discussed especially with a focus on the recurrence. Moreover, a comprehensive treatment algorithm has been presented.

Development and evaluation of a patient-specific surgical simulator for endoscopic colloid cyst resection

OBJECTIVE

Endoscopic resection of third-ventricle colloid cysts is technically challenging due to the limited dexterity and visualization provided by neuroendoscopic instruments. Extensive training and experience are required to master the learning curve. To improve the education of neurosurgical trainees in this procedure, a synthetic surgical simulator was developed and its realism, procedural content, and utility as a training instrument were evaluated.

METHODS

The simulator was developed based on the neuroimaging (axial noncontrast CT and T1-weighted gadolinium-enhanced MRI) of an 8-year-old patient with a colloid cyst and hydrocephalus. Image segmentation, computer-aided design, rapid prototyping (3D printing), and silicone molding techniques were used to produce models of the skull, brain, ventricles, and colloid cyst. The cyst was filled with a viscous fluid and secured to the roof of the third ventricle. The choroid plexus and intraventricular veins were also included. Twenty-four neurosurgical trainees performed a simulated colloid cyst resection using a 30° angled endoscope, neuroendoscopic instruments, and image guidance. Using a 19-item feedback survey (5-point Likert scales), participants evaluated the simulator across 5 domains: anatomy, instrument handling, procedural content, perceived realism, and confidence and comfort level.

RESULTS

Participants found the simulator's anatomy to be highly realistic (mean 4.34 ± 0.63 [SD]) and appreciated the use of actual instruments (mean 4.38 ± 0.58). The procedural content was also rated highly (mean 4.28 ± 0.77); however, the perceived realism was rated slightly lower (mean 4.08 ± 0.63). Participants reported greater confidence in their ability to perform an endoscopic colloid cyst resection after using the simulator (mean 4.45 ± 0.68). Twenty-three participants (95.8%) indicated that they would use the simulator for additional training. Recommendations were made to develop complex case scenarios for experienced trainees (normal-sized ventricles, choroid plexus adherent to cyst wall, bleeding scenarios) and incorporate advanced instrumentation such as side-cutting aspiration devices.

CONCLUSIONS

A patient-specific synthetic surgical simulator for training residents and fellows in endoscopic colloid cyst resection was successfully developed. The simulator's anatomy, instrument handling, and procedural content were found to be realistic. The simulator may serve as a valuable educational tool to learn the critical steps of endoscopic colloid cyst resection, develop a detailed understanding of intraventricular anatomy, and gain proficiency with bimanual neuroendoscopic techniques.

Endoscopic removal of recurrent colloid cysts

OBJECTIVE

Removal of colloid cysts of the third ventricle using a purely endoscopic method has been established as a safe and advantageous technique. It is hypothesized that endoscopic removal in recurrent cases might pose more technical challenges and result in less success. The objective of this study was to assess the feasibility and outcomes of using a purely endoscopic approach for the management of recurrent colloid cysts compared to primary cysts.

METHODS

A retrospective cohort study was performed on patients who underwent purely endoscopic removal of their colloid cyst. Descriptive statistics were compared for patients undergoing surgery for a recurrent cyst and those for a control cohort undergoing surgery for a primary cyst. Bivariate analysis was conducted using a Fisher's exact test for categorical variables and Mann-Whitney U-test for continuous variables.

RESULTS

In total, 121 patients had a primary colloid cyst endoscopically removed and 10 patients had a total of 11 recurrent cysts removed. Recurrence or progression after surgery occurred in 3 (2.5%) cases in the primary cyst group and 2 (18.2%) cases in the recurrent cyst group. Symptomatic presentation during the follow-up period occurred in 6 (54.5%) cases in the recurrent cyst group versus 75 (62%) cases in the primary cyst group (p = 0.749). Two patients (20%) in the recurrent group had a second recurrence in a mean period of 30 months (1 patient at 15 and 1 patient at 45 months). One of these patients required a tertiary endoscopic removal 8 years after the second resection. No immediate postoperative complications or new morbidities were observed after repeat endoscopic surgery. The authors' findings indicated a nonsignificant trend toward a higher recurrence rate (18.2% vs 2.5%, p = 0.055) and a decreased proportion of complete removal (90.9% vs 81.8%, p = 0.296) in the recurrent cyst group compared to the primary cyst group. However, a significantly higher rate of preoperative hydrocephalus was observed in the primary cyst group compared with the recurrent cyst group (63.6% vs 18.2%, p = 0.007).

CONCLUSIONS

Purely endoscopic approaches for the removal of recurrent colloid cysts of the third ventricle are feasible and equally safe compared with endoscopic removal of primary cysts. The study's findings did not show a statistically significant difference in the rate of recurrence between the 2 groups. The proportion of patients with symptomatic cysts on presentation was lower in patients with recurrent cysts than in patients with primary cysts. Due to the high rate of complete removal with negligible morbidity, the authors continue to advocate for an endoscopic removal at the time of cyst recurrence.

Endoscopic colloid cyst excision: surgical techniques and nuances

BACKGROUND

Endoscopic excision of colloid cysts is currently well established as a minimally invasive and highly effective technique that is associated with less morbidity in comparison to microsurgical resection.

METHODS

Operative charts and videos of patients undergoing endoscopic colloid cyst excision were retrieved from the senior author's database of endoscopic procedures and reviewed. This revealed nine trans-foraminal and three trans-septal procedures. Description of the surgical techniques was then formulated.

CONCLUSIONS

Variation of the technique is based on the specific patho-anatomical features of the colloid cyst being resected. For the trans-foraminal approach, we think that the rotational technique is associated with a more complete removal of the cyst wall and consequently lower recurrence rate.

The impact of surgical resection on headache disability and quality of life in patients with colloid cyst

Introduction Colloid cysts are histologically benign but can present with a broad spectrum of symptoms. A systematic review of the literature did not reveal any patient-centered data on the headache disability and quality of life (QoL) of these patients. Methods This is a retrospective cohort study of 187 colloid cyst patients from the Colloid Cyst Survival Group who completed a survey that included demographic data, clinical data, a modified QoL survey (SF36v2), and a headache disability inventory or index (HDI). Results Using multivariable linear regressions, we confirmed that the physical (PCS) and mental (MCS) components of SF-36 were significantly increased in the surgery group after adjustment for various baseline characteristics ( p = 0.025; p = 0.006). Self-reported headache disability was significantly decreased with surgery when adjusted for the same baseline characteristics ( p = 0.02). Finally, patients with an incidental diagnosis of colloid cyst reported similar benefits from surgery in PCS, MCS and HDI. Conclusion Our results suggest that colloid cyst patients who underwent a surgical resection self-report a better QoL and less headache disability compared with patients who did not undergo surgery. Future prospective studies with baseline measures of QoL are indicated to confirm our findings.

Natural history of colloid cysts of the third ventricle

OBJECTIVE Colloid cysts are rare, histologically benign lesions that may result in obstructive hydrocephalus and death. Understanding the natural history of colloid cysts has been challenging given their low incidence and the small number of cases in most reported series. This has complicated efforts to establish reliable prognostic factors and surgical indications, particularly for asymptomatic patients with incidental lesions. Risk factors for obstructive hydrocephalus in the setting of colloid cysts remain poorly defined, and there are no grading scales on which to develop standard management strategies. METHODS The authors performed a single-center retrospective review of all cases of colloid cysts of the third ventricle treated over nearly 2 decades at Washington University. Univariate analysis was used to identify clinical, imaging, and anatomical factors associated with 2 outcome variables: symptomatic clinical status and presentation with obstructive hydrocephalus. A risk-prediction model was defined using bootstrapped logistic regression. Predictive factors were then combined into a simple 5-point clinical scale referred to as the Colloid Cyst Risk Score (CCRS), and this was evaluated with receiver-operator characteristics. RESULTS The study included 163 colloid cysts, more than half of which were discovered incidentally. More than half of the incidental cysts (58%) were followed with surveillance neuroimaging (mean follow-up 5.1 years). Five patients with incidental cysts (8.8%) progressed and underwent resection. No patient with an incidental, asymptomatic colloid cyst experienced acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly half (46.2%) of symptomatic patients presented with hydrocephalus. Eight patients (12.3%) presented acutely, and there were 2 deaths due to obstructive hydrocephalus and herniation. The authors identified several factors that were strongly correlated with the 2 outcome variables and defined third ventricle risk zones where colloid cysts can cause obstructive hydrocephalus. No patient with a lesion outside these risk zones presented with obstructive hydrocephalus. The CCRS had significant predictive capacity for symptomatic clinical status (area under the curve [AUC] 0.917) and obstructive hydrocephalus (AUC 0.845). A CCRS ≥ 4 was significantly associated with obstructive hydrocephalus (p < 0.0001, RR 19.4). CONCLUSIONS Patients with incidentally discovered colloid cysts can experience both lesion enlargement and symptom progression or less commonly, contraction and symptom regression. Incidental lesions rarely cause acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly one-half of patients with symptomatic colloid cysts present with obstructive hydrocephalus, which has an associated 3.1% risk of death. The CCRS is a simple 5-point clinical tool that can be used to identify symptomatic lesions and stratify the risk of obstructive hydrocephalus. External validation of the CCRS will be necessary before objective surgical indications can be established. Surgical intervention should be considered for all patients with CCRS ≥ 4, as they represent the high-risk subgroup.

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.