Colloid cyst Spetzler vs endoscope

Eric M. Horn, M.D., Ph.D. 

Division of Neurological Surgery, 

Barrow Neurological Institute, 

St. Joseph’s Hospital and Medical Center, 

Phoenix, Arizona 

Iman Feiz-Erfan, M.D. 





Ruth E. Bristol, M.D. 





Gregory P. Lekovic, M.D., 

Ph.D., J.D. 





Pamela W. Goslar, Ph.D. 

Division of Trauma, 



Kris A. Smith, M.D. 





Peter Nakaji, M.D. 





Robert F. Spetzler, M.D. 





Reprint requests: 

Robert F. Spetzler, M.D., 

c/o Neuroscience Publications, 


350 West Thomas Road, 

Phoenix, AZ 85013. 

Email: neuropub@chw.edu 

Received, June 1, 2006. 

Accepted, December 5, 2006. 

TREATMENT OPTIONS FOR THIRD VENTRICULAR 

COLLOID CYSTS: COMPARISON OF OPEN 

MICROSURGICAL VERSUS ENDOSCOPIC RESECTION 

OBJECTIVE: We retrospectively reviewed our experience treating third ventricular colloid 

cysts to compare the efficacy of endoscopic and transcallosal approaches. 

METHODS: Between September 1994 and March 2004, 55 patients underwent third ventricular 

colloid cyst resection. The transcallosal approach was used in 27 patients; the 

endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of 

hydrocephalus were similar between the two groups. 

RESULTS: The operating time and hospital stay were significantly longer in the transcallosal 

craniotomy group compared with the endoscopic group. Both approaches 

led to reoperations in three patients. The endoscopic group had two subsequent craniotomies 

for residual cysts and one repeat endoscopic procedure because of equipment 

malfunction. The transcallosal craniotomy group had two reoperations for fractured 

drainage catheters and one operation for epidural hematoma evacuation. The transcallosal 

craniotomy group had a higher rate of patients requiring a ventriculoperitoneal 

shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up 

demonstrated more small residual cysts in the endoscopic group than in the 

transcallosal craniotomy group (seven versus one). Overall neurological outcomes, 

however, were similar in the two groups. 

CONCLUSION: Compared with transcallosal craniotomy, neuroendoscopy is a safe 

and effective approach for removal of colloid cysts in the third ventricle. The endoscope 

can be considered a first-line treatment for these lesions, with the understanding 

that a small number of these patients may need an open craniotomy to remove residual 

cysts. 

KEY WORDS: Hydrocephalus, Intracranial tumor, Intraventricular 

CLINICAL STUDIES 

Neurosurgery 60:613–620, 2007 DOI: 10.1227/01.NEU.0000255409.61398.EA www.neurosurgery-online.com 

Colloid cysts are benign intracranial 

lesions that account for 0.5 to 1.0% of 

brain tumors. They are almost always 

located in the third ventricle (6, 35). They typically 

present with progressive headaches 

caused by obstructive hydrocephalus (16, 43). 

A few patients, however, have signs of severe 

obstructive hydrocephalus and present with 

sudden death (17). Consequently, early detection 

and treatment are recommended. 

The traditional treatment for these cysts has 

been a transcallosal or transcortical craniotomy 

and resection. Increasingly, however, the endoscope 

is being used for resection. Therefore, 

we retrospectively reviewed our experience 

treating third ventricular colloid cysts to com- 

pare the efficacy of the endoscopic and transcallosal 

approaches. 

PATIENTS AND METHODS 

The surgical database at the Barrow Neurological 

Institute was retrospectively reviewed 

for all patients undergoing operation for colloid 

cysts. The endoscopic approach for treating 

colloid cysts of the third ventricle was initiated 

at our institution during the early 1990s, 

and this review spans from September 1994 to 

March 2004. During this time, 55 consecutive 

patients were treated for third ventricular colloid 

cysts; 27 patients underwent a transcallosal 

approach and 28 underwent an endo- 

NEUROSURGERY VOLUME 60 | NUMBER 4 | APRIL 2007 | 613

HORN ET AL. 

scopic approach. The proportions of approaches were similar 

throughout the study period (seven endoscopic and four transcallosal 

approaches between 1994 and 1996; 13 endoscopic 

and nine transcallosal approaches between 1997 and 2000; eight 

endoscopic and 14 transcallosal approaches between 2001 and 

2004). The most common presenting symptom in both groups 

was headache (Table 1). At presentation, there were no differences 

in age, sex, cyst diameter, or presence of hydrocephalus 

between the two groups (Table 1). The rationale for resection 

was based on presenting symptoms. If the patient had a severe 

headache from hydrocephalus or neurological symptoms, surgery 

was offered. If the patient was asymptomatic or had mild 

symptoms, then surgery or observation was offered. Only 

patients who underwent surgery were included in the study. 

The decision to use either approach was based on the preference 

of the eight treating surgeons. Four surgeons used the 

transcallosal approach exclusively, and three surgeons used the 

endoscopic approach exclusively. One surgeon used the endoscopic 

approach in all but one case in which the transcallosal 

approach was used because two endoscopic attempts at an outside 

facility had failed. Thus, the groups were well matched in 

terms of presentation. The choice of approach was based solely 

on the patient’s treating physician. 

Standard microsurgical techniques were used in patients 

undergoing the transcallosal approach. A rigid endoscope was 

manipulated freehand in all patients undergoing the endoscopic 

approach (Fig. 1). All endoscopes used had either a 0- or 

30-degree viewing angle with one channel for insertion of 

microinstruments. Because its use became routine for all cranial 

operations at our institution before the study period, image 

guidance was used equally with the two approaches. 

The primary outcomes compared between the two 

approaches were operative time, complications, length of hospitalization, 

and residual or recurrence of cyst. Each patient’s 

last follow-up magnetic resonance imaging (MRI) or computed 

tomographic scan was used to evaluate the presence of residual 

or recurrent cysts (range, 1–54 mo). Intermediate neurological 

outcomes were also compared, with special attention to memory, 

motor, and cognitive deficits, as measured by standard 

TABLE 1. Demographic information for patients undergoing 

endoscopic or transcallosal approaches for removal of third ventricular 

colloid cystsa Endoscopic Transcallosal 

(n � 28) (n � 27) 

Age (mean � SD) 49 � 14 yr 45 � 15 yr 

Men (no. men/total patients) 

Presentation 

50% (14/28) 48% (13/27) 

Headache (no./total) 75% (21/28) 56% (15/27) 

Neurological sign (no./total) 21% (6/28) 26% (7/27) 

Incidental (no./total) 4% (1/28) 19% (5/27) 

Cyst diameter (mean � SD) 1.3 � 0.5 cm 1.3 � 0.5 cm 

Hydrocephalus (no./total) 61% (17/28) 63% (17/27) 

a SD, standard deviation. 

A B 

FIGURE 1. A, immediate preoperative axial T1-weighted MRI scan with 

contrast shows a colloid cyst in the foramen of Monro. B, axial T1-weighted 

MRI scan without contrast 2 weeks after endoscopic resection. 

neuropsychological tests. These variables were analyzed using 

Fisher’s exact test, Student’s t test, or Mann-Whitney rank sum 

test, with P values less than 0.05 deemed significant. 

RESULTS 

The operating time was significantly longer in the transcallosal 

craniotomy group than in the endoscopic group (Table 2). 

The length of stay in the intensive care unit was similar in the 

two groups but the overall length of hospitalization was 

TABLE 2. Procedural and postoperative hospital stay comparisons 

between patients treated via an endoscopic or transcallosal 

craniotomy resection of third ventricular colloid cystsa Endoscopic Transcallosal 

(n � 28) (n � 27) 

Operative time (mean � SEM) 173.9 � 6.3 266.8 � 8.4 

min minb Complications 

None (no./total) 75% (21/28) 56% (15/27) 

Reoperation (no./total) 11% (3/28) 11% (3/27) 

VPS (no./total) 7% (2/28) 19% (5/27) 

Infection (no./total) 0% (0/28) 19% (5/27) 

Neurological (no./total) 11% (3/28) 11% (3/27) 

Other (no./total) 0% (0/28) 4% (1/27) 

ICU stay (mean � SEM) 2.3 � 0.4 d 3.3 � 0.6 d 

Hospital stay (mean � SEM) 5.4 � 1.3 d 6.3 � 0.8 db Discharge destination 

Home (no./total) 89% (25/28) 93% (25/27) 

Rehabilitation (no./total) 7% (2/28) 4% (1/27) 

ECF (no./total) 4% (1/28) 4% (1/27) 

a SEM, standard error of the means; VPS, ventriculoperitoneal shunt; ICU, intensive 

care unit; ECF, extended care facility. 

b P �0.05. 

614 | VOLUME 60 | NUMBER 4 | APRIL 2007 www.neurosurgery-online.com

slightly longer in the transcallosal craniotomy group (Table 2). 

The overall complication rate was slightly higher in the transcallosal 

group than in the craniotomy group but this finding 

was nonsignificant (Table 2). Except for the presence of hydrocephalus, 

there were no differences in the complication rates 

across any of the categories of presentation. Patients who presented 

with hydrocephalus had a higher complication rate 

(47%) than those without hydrocephalus (19%). 

In each approach, three patients underwent reoperation 

(Table 2). In the endoscopic group, two patients underwent a 

subsequent craniotomy for residual cysts. One patient underwent 

another endoscopic procedure because equipment malfunctioned 

during the original approach. In the transcallosal 

craniotomy group, two patients required a reoperation for 

fractured drainage catheters, and an epidural hematoma was 

evacuated in one patient. Five patients in the transcallosal craniotomy 

group required a ventriculoperitoneal shunt compared 

with two patients in the endoscopic group. A significant 

residual was not found in any of the patients who subsequently 

required shunting. One potential reason for persistent hydrocephalus 

in these patients was the presence of blood products 

in the cerebrospinal fluid from the surgical procedure. The 

infection rate was also higher in the transcallosal craniotomy 

group than in the endoscopic group (five versus none). Postoperatively, 

all patients had an external drain in place while in 

the intensive care unit. Therefore, this difference in infection 

rate may reflect the longer (but nonsignificant) intensive care 

unit stay of 1 day in the transcallosal group. 

The number of neurological complications in the two groups 

was similar. In the transcallosal craniotomy group, two patients 

developed new-onset seizures and one patient experienced a 

venous infarct. In the endoscopic group, two patients had significant 

memory impairment and one patient had hemiparesis 

from an internal capsule injury. In both groups, a similar number 

of patients were discharged to home, a rehabilitation center, 

or an extended care facility (Table 2). 

Intermediate follow-up data was available for 45 (82%) of the 

55 patients (Table 3). More patients in the endoscopic group 

had residual cysts than in the transcallosal craniotomy group, 

and there were no recurrences in either group (Fig. 2). 

However, fewer patients in the transcallosal craniotomy group 

underwent intermediate follow-up imaging (Table 3). Preoperative 

symptoms improved significantly in most patients, 

and overall neurological outcomes were similar in the two 

groups (Table 3). 

DISCUSSION 

To our knowledge, we present the largest comparison of 

endoscopic and transcallosal craniotomy for resection of third 

ventricular colloid cysts. Two other small series have compared 

these techniques but small patient samples precluded adequate 

comparisons (28, 34). Although the types of complications differed 

in our two groups, the overall rates of complications were 

similar. The overall complication rate in the entire cohort (20 

out of 55 patients) was similar to other reported series (28, 34). 

TREATMENT OPTIONS FOR THIRD VENTRICULAR COLLOID CYSTS 

FIGURE 2. Kaplan-Meier plot demonstrating residual-free intervals 

between the transcallosal and endoscopic approaches. There was a significant 

difference in the intervals between the two groups (P � 0.05; χ 2 ). 

TABLE 3. Follow-up information of patients treated endoscopically 

and with a transcallosal craniotomy for resection of third 

ventricular colloid cystsa Endoscopic Transcallosal 

(21/28) (24/27) 

Average follow-up (mean � SD ) 10.1 � 2.2 10.9 � 3.4 

Residual cyst 

mo mo 

No residual (no./total) 53% (10/19) b 94% (16/17) b 

Small residual (no./total) 37% (7/19) b 6% (1/17) b 

Large residual (no./total) 11% (2/19) b 0% (0/17) b 

No scans performed (no./total) 

Neurological outcome 

2/21 7/24 

Improvement (no./total) 76% (16/21) 79% (19/24) 

Unchanged (no./total) 10% (2/21) 13% (3/24) 

Worsened (no./total) 14% (3/21) 8% (2/24) 

a SD, standard deviation. 

b P �0.05. 

Furthermore, there was no correlation between surgeons in 

terms of complication rates. Despite these complications, an 

overwhelming majority of patients recovered well enough to be 

discharged to home. All patients discharged to an extended 

care facility or rehabilitation facility had neurological symptoms 

at presentation. 

Not surprisingly, the length of hospitalization was slightly 

shorter in the endoscopic group than in the transcallosal craniotomy 

group. Although not specifically analyzed, this difference 

may translate to a more cost-effective treatment. However, 

caution is warranted because the rate of residual or recurrent 

cysts was higher in the endoscopic group during the intermediate 

follow-up period in these patients. Even after the most tech- 


HORN ET AL. 

nically successful endoscopic procedures, these patients need 

close long-term follow-up if a residual cyst remains. We recommend 

MRI scanning 3 months after resection. If the cyst remains 

stable at least 4 years after resection, MRI scan studies can then 

be obtained at doubling intervals (i.e., 6 mo, 1 yr, 2 yr, etc.). 

Endoscopic Treatment 

Traditionally, colloid cysts of the third ventricle have been 

treated primarily through a transcortical or transcallosal craniotomy 

approach (17, 19, 21, 24, 27, 29, 37, 39, 43, 49, 51). 

Indeed, the transcallosal approach was the primary method 

used at our institution until the evolution of endoscopy 

enabled a viable alternative. Since its description in 1983 (46), 

the use of endoscopy for removing third ventricular colloid 

cysts has gained popularity. Several series have demonstrated 

the efficacy and safety of endoscopic resection of colloid cysts 

(1, 13–15, 23, 30, 36, 47). 

One criticism of the endoscopic approach is the decreased 

ability to resect cysts completely compared with open 

approaches. In reality, the extent of resection varies widely from 

series to series. In one series, most of the 20 patients treated had 

residual cysts (23). Only one patient in this series, however, 

needed a reoperation for recurrence 1 year after endoscopic 

treatment. In another large series, cysts were resected completely 

in 80% of the patients treated via the endoscope (30). 

After an average follow-up period of 2 years, no patient with 

either total or subtotal resection developed symptomatic recurrence. 

In an earlier series, 12 out of 15 patients had residual 

cyst, but none needed reoperation (13). Likewise, our results 

demonstrated a high rate of residual cysts (9 out of 21 cysts), 

only two of which needed a reoperation for further resection. 

This finding highlights that, although an incomplete resection 

is acceptable, serial imaging and long-term follow-up periods 

are warranted. Because our follow-up period is relatively short, 

we cannot state definitively that the final recurrence rates in the 

two populations are significantly different. On the basis of our 

data, however, one can expect a higher rate of residual or recurrent 

cysts in the immediate postoperative period. 

Although the follow-up period in these series is relatively 

long, a longer follow-up period was recommended for each 

patient because the potential for regrowth after incomplete 

resection is unknown. Because there is a potential for rapid 

deterioration associated with devastating neurological morbidity 

or even death, close monitoring with MRI scan at progressively 

longer intervals is warranted (4, 7, 11, 17, 50). If complete 

resection is accomplished via the endoscopic approach, the 

schedule for follow-up imaging can be more relaxed. 

Despite being minimally invasive, endoscopy is still associated 

with complications. In fact, severe complications, such as 

hemiparesis and memory deficits, can occur (23, 30, 34). Of our 

endoscopic patients, two patients had permanent memory 

deficits (one mild and one severe) and one patient had moderate 

hemiparesis. Recently, we have used a shallower trajectory 

with a more lateral starting point. These modifications allow 

the endoscope to be positioned further inferior to the fornix. 

Significant traction on this structure is thereby avoided, and the 

risk for memory impairment should decrease. Newer technology 

in the design of endoscopes, including larger ports for 

instruments and wider-angle lenses, should help decrease the 

rate of residual cysts. We are also now using a metal microtube 

to aid in the direct aspiration of the cyst. The key to this technique 

is that the rigidity of the tube allows significant negative 

pressure to develop to aspirate the highly viscous contents of 

the cyst. 

Open Craniotomy Approaches 

Since Dandy (12) first reported his results for the surgical 

treatment of third ventricular colloid cysts, both the transcortical 

and transcallosal approaches have been widely used (10, 12, 

16, 19, 21, 24, 27, 37, 43, 49). When microsurgical techniques 

and contemporary imaging became available, the morbidity 

and mortality rates associated with these approaches decreased 

considerably (9, 29, 35, 39). Compared with endoscopic techniques, 

these approaches offer a better view and enable complete 

resection of cysts. Some would argue, however, that an 

endoscope with angled optics can provide equal or better visualization 

of the cyst. There is little disagreement regarding the 

advantages of instrument manipulation during microsurgery 

compared with endoscopic surgery. 

Although the transcortical and transcallosal approaches have 

been reported to be relatively safe, they can still be associated 

with serious complications. One of our patients experienced a 

venous infarction after thrombosis from cortical veins and had 

residual neurological deficits. Other investigators have also 

reported this complication (20, 37). Although this type of complication 

would not occur in a transcortical approach, we prefer 

the transcallosal approach, which avoids damage to cortical 

tissue. When image guidance is used, however, a right frontal 

transcortical approach seems to be associated with a very low 

complication profile and is a reasonable alternative. In other 

series, use of transcallosal or transcortical approaches has also 

been associated with memory impairment (3, 25, 26, 37, 40). 

Even with the risk of complications associated with the transcallosal 

approach, the reoperation rate for residual cysts was 

zero. This is an important difference compared with the endoscopic 

approach, in which residual cysts are common. At this 

time, to our knowledge, there are no adequate preoperative 

predictors of success using endoscopy for colloid cyst resection. 

Until this issue is thoroughly analyzed, surgeons and patients 

must accept the possibility that another surgical procedure may 

be needed to achieve a cure after an endoscopic approach. 

Alternative Treatments 

Several alternatives to the transcallosal/transventricular 

craniotomy or endoscopic approach exist for the resection of 

colloid cysts. These options include conservative observation, 

isolated ventriculoperitoneal shunting, and infratentorial 

supracerebellar approaches (16, 24, 33). Conservative therapy 

has been advocated for older, asymptomatic patients who do 

not display ventriculomegaly (44, 45). However, this treatment 

is controversial, considering the many case reports of sudden 


deterioration and death caused by rapidly enlarging cysts (4, 7, 

11, 17, 50). 

A stereotactically placed tube retractor has been used to create 

a minimally invasive transventricular approach (2, 5, 8, 32). This 

approach is a compromise between the small aperture available 

with endoscopy and the greater maneuverability associated with 

microsurgery. Although these series report good success rates, 

the technique requires a larger corticectomy than endoscopy and 

more limited working angles than open microsurgery. 

Since its description in 1978 (5), aspiration of the cyst using 

stereotactic needles has also been studied extensively. Early 

reports showed promising results, but the rate of residual and 

recurrent cysts was unacceptably high in subsequent studies 

(22, 31, 38, 41, 42, 48). Although two studies identified imaging 

factors that helped predict success with this technique, it has 

now largely been replaced by endoscopy (18, 31). 

CONCLUSIONS 

The use of the endoscope to remove colloid cysts in the third 

ventricle is a safe and effective approach compared with transcallosal 

craniotomy. The endoscopic approach is associated 

with a shorter operative time, shorter hospital stay, and lower 

infection rate than the transcallosal approach. However, more 

patients treated endoscopically needed a reoperation for residual 

cyst. On the basis of these results, the endoscope can be 

considered as a first-line treatment for these lesions, with the 

understanding that a small number of these patients may need 

a transcallosal craniotomy to remove residual cysts. 

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49. Solaroglu I, Beskonakli E, Kaptanoglu E, Okutan O, Ak F, Taskin Y: 

Transcortical-transventricular approach in colloid cysts of the third ventricle: 

Surgical experience with 26 cases. Neurosurg Rev 27:89–92, 2004. 

50. Torrey J: Sudden death in an 11-year-old boy due to rupture of a colloid cyst of 

the third ventricle following ‘disco-dancing.’ Med Sci Law 23:114–116, 1983. 

51. Villani R, Papagno C, Tomei G, Grimoldi N, Spagnoli D, Bello L: Transcallosal 

approach to tumors of the third ventricle. Surgical results and neuropsychological 

evaluation. J Neurosurg Sci 41:41–50, 1997. 

COMMENTS 

Horn et al. have retrospectively reviewed the institutional experience 

of surgically treated third ventricle colloid cysts at the Barrow 

Neurological Institute between 1994 and 2004. Fifty-five patients were 

treated; of these, follow-up data was available for 45 patients. Twentyeight 

patients underwent endoscopic and 27 underwent transcallosal 

microsurgical procedures. The follow-up period ranged from 1 to 54 

months. Thus, it is necessary to find the patients who were lost to follow-up 

to rule out recurrences and residuals and to follow all patients 

for a much longer period of time. A mean follow-up period of less 

than 1 year is not satisfactory, particularly because a large fraction of 

the patients had residual cyst. Colloid cysts remain important to diagnose 

and treat, and the mortality and morbidity rates from delayed 

diagnoses are considerable (2, 4). 

However, I feel that this is still an important contribution. It provides 

an attempt at comparing two different surgical therapies and, thus, is 

important for many reasons. The authors are to be commended for 

their honest report. It is, however, difficult to follow the reasoning 

behind their conclusions. Their data showed that endoscopy at their 

center was inferior to transcallosal surgery: A residual cyst was 

detectable in nine out of 21 patients after endoscopic surgery. The reasoning 

that only a fraction of patients with residuals needed surgery is 

misleading because the need for operation of a potentially growing 

residual can only be assessed after a true long-term follow-up period 

(4). Repeated surgery and the frequent magnetic resonance imaging follow-up 

examinations recommended for the failures would rapidly nullify 

and reverse any economic gain from the shorter operative time 

and hospital. The complications after endoscopy included severe memory 

deficit and hemiparesis, whereas transcallosal surgery led to reoperation 

for surgical complications or epilepsy. Thus, the complication 

rate was higher than expected in both groups. Today, it is reasonable to 

expect cure from a colloid cyst (3, 5, 6) without permanent morbidity 

from the treatment (1, 3, 5, 6). We have had one radiologically visible 

residual and no severe complications in our transcallosal cyst surgery 

series, which now includes 37 patients. The residual we observed was 

early in the series. Meticulous microsurgery allows preservation of 

bridging veins, avoidance of cortical and forniceal damage, radical cyst 

removal, and minimal bleeding. Postoperative drainage or shunting is 

usually not necessary when hemorrhage is well controlled. 

It was surprising that as many as eight different surgeons had taken 

part in the surgical treatment. Given this, each would have operated on 

an average of less than 0.7 patients annually. This may be one reason 

for the high complication rate and low grade of tumor control. One of 

the findings in the institutional series (5) was that all serious complications 

occurred to the few surgeons who had limited exposure to third 

ventricular surgery. It is probable that concentration of sensitive surgery 

would allow improved results. 

It is important to observe that, although the trial design allowed a 

comparison of two treatment modes, which is in agreement with the 

reasoning behind evidence-based medicine, a major caveat in the comparison 

is that the results were worse than expected with both treatment 

modes. It is questionable whether or not the comparison can be 

generalized under such conditions. My conclusion, which is at variance 

with the authors, is that the data indicate that transcallosal surgery 

was a better treatment than endoscopic surgery and that total outcomes 

may have been better if only one treatment mode was used by 

a limited number of surgeons. 

Tiit Mathiesen 

Stockholm, Sweden 

1. Decq P, Le Guerinel C, Brugieres P, Djindjian M, Silva D, Keravel Y, Melon E, 

Nguyen JP: Endoscopic management of colloid cysts. Neurosurgery 

42:1288–1296, 1998. 

2. De Witt Hamer PC, Verstegen MJ, De Haan RJ, Vandertop WP, Thomeer RT, 

Mooij JJ, van Furth WR: High risk of acute deterioration in patients harboring 

symptomatic colloid cysts of the third ventricle. J Neurosurg 96:1041–1045, 

2002. 

3. Hernesniemi J, Leivo S: Management outcome in third ventricular colloid 

cysts in a defined population: A series of 40 patients treated mainly by transcallosal 

microsurgery. Surg Neurol 45:2–14, 1996. 

4. Mathiesen T, Grane P, Lindquist C, von Holst H: High recurrence rate following 

aspiration of colloid cysts in the third ventricle. J Neurosurg 78:748–752, 

1993. 

5. Mathiesen T, Grane P, Lindgren L, Lindquist C: Third ventricle colloid cysts: 

A consecutive 12-year series. J Neurosurg 86:5–12, 1997. 

6. Teo C: Complete endoscopic removal of colloid cysts: Issues of safety and efficacy. 

Neurosurg Focus 6:e9, 1999. 

The authors compared outcomes after transcallosal resection or endoscopic-assisted 

transcortical resection for patients with colloid cysts. 

As might be expected, endoscopic surgeries were associated with a 

higher rate for subtotal cyst removal, in which a small remnant was 

left. There was no significant difference in results, and the surgeons in 

this group who performed the transcallosal surgeries apparently continue 

to do so. I have long thought that this surgery is best performed 


y a surgeon who is particularly comfortable with his or her chosen 

approach. Given the chance for cognitive or other functional morbidity, 

it is not surprising that neurosurgeons would not be quick to 

embark on a new surgical strategy. At our institution, stereotactic 

transcortical microsurgical resection has evolved into stereotactic 

transcortical endoscopic-associated resection for many patients. We 

continue to use standard microsurgical instruments for both 

approaches. How surgeons will use the information provided in this 

report will be interesting. Will they change their route down to the 

cyst? Will they change their technique for magnification and illumination 

of the surgical field? 

Douglas Kondziolka 

Pittsburgh, Pennsylvania 

Discussions regarding the management of patients with colloid cysts 

clearly demonstrate that there is an inverse relationship between 

the frequency of a disorder and the certainty surgeons express about 

the best method by which to treat it. Consequently, most case series on 

colloid cysts conclude that a particular surgical approach is superior to 

other alternatives, although the number of patients undergoing operation 

is generally small, and there is often no reliable control group 

available for comparison. In this retrospective study of patients with 

mostly symptomatic colloid cysts (only 9% were asymptomatic), the 

authors report that endoscopic removal of colloid cysts was safe with 

outcomes equal or slightly better when compared with patients undergoing 

a transcallosal resection. Strengths of this study include a relatively 

large number of patients (n = 55) and the similarity of the two 

groups with regard to age, symptoms, cyst size, and presence of hydrocephalus. 

Notably, more patients had a small residual cyst after endoscopic 

removal. The follow-up period is not sufficient to conclude that 

the symptomatic recurrence rates will be equivalent at a later date. 

After reviewing the experience at our center on the presentation and 

natural history of colloid cysts (1, 2), I have developed some thoughts 

about this problem that are not generally appreciated. First, a percentage 

of well informed patients with asymptomatic colloid cysts can be safely 

managed with observation and serial imaging. However, before this can 

be recommended, it must be clearly established that the patient is without 

cyst-related symptoms, which is ideally confirmed through repeated 

examinations by more than one neurosurgeon or neurologist. In addition, 

these patients must understand that they have a potentially lethal 

condition if they become symptomatic and do not seek or have access to 

immediate medical attention. Second, referral of patients with newly 

diagnosed colloid cysts to tertiary care centers makes medicolegal sense 

for many neurosurgeons, with the exception being patients presenting 

with progressive symptoms and acute hydrocephalus. For such patients, 

placement of an external ventricular drain with appropriate transfer 

after the patient has been stabilized is a very reasonable approach. 

Several times each year since the publication of my studies, I have been 

asked to review cases to determine whether or not surgery should have 

been performed; if surgery was performed, I am asked whether or not 

the neurosurgeon was qualified to perform such a rare surgery. In fact, I 

would speculate that the incidence of lawsuits arising from the management 

and surgery of patients with colloid cysts is higher than practically 

any other condition affecting the nervous system of adults. 

Bruce E. Pollock 

Rochester, Minnesota 

1. Pollock BE, Huston J 3rd: Natural history of asymptomatic, untreated colloid 

cysts of the third ventricle. J Neurosurg 91:364–369, 1999. 


2. Pollock BE, Schriener S, Huston J 3rd: A theory on the natural history of colloid 

cysts of the third ventricle. Neurosurgery 46:1077–1083, 2000. 

Iwould expect that there will be an ongoing debate for years to come 

concerning the relative merits of endoscopic compared with microsurgical 

removal of colloid cysts. This dispute will cease only when follow-up 

intervals of 10 years or greater are available for a substantial 

number of patients who have undergone endoscopic resection. Horn et 

al., however, have demonstrated reduced operative time and hospital 

stay with endoscopic removal of colloid cysts, disparities that will not 

be influenced by longer follow-up periods. These differences have also 

been shown in previously published retrospective series and are, therefore, 

not debated. Certain benefits of endoscopic colloid cyst resection 

are, therefore, irrefutable. 

Although the degree of resection is important in colloid cyst 

removal, it would be simplistic to gauge successful surgery on the 

presence of residual cyst after endoscopic removal. Incomplete colloid 

cyst resection admittedly occurs more frequently and is actually considered 

preferable in some circumstances in endoscopic resection. 

However, one needs to be diligent in the interpretation of “residual colloid 

cyst.” There is substantial difference between magnetic resonance 

imaging-defined residual disease and cyst wall remnants that are seen 

at the time of endoscopic removal. In endoscopic colloid cyst removal, 

any adherent cyst wall remnants after complete cyst evacuation should 

be extirpated with coagulation, a technical advantage that was not possible 

with stereotactic aspiration. These “endoscopic” remnants are 

commonly, but probably inaccurately, referenced as the cause of higher 

recurrence rates in endoscopic resection. 

In this work by Horn et al., it is uncertain if the two patients who 

first had an endoscopic removal underwent a second procedure for 

residual colloid cyst (cyst wall and contents) or “endoscopic” remnants 

(coagulated cyst wall). What is clear is that no patient in either group 

experienced radiographic or clinical progression. Furthermore, there is 

no mention regarding the interval of time between the two procedures. 

As a result, it remains inconclusive whether or not recurrence rates are 

greater in patients undergoing endoscopic removal. It will be prudent 

to include accurate assessments of degree of resection and longer follow-up 

intervals in subsequent works. 

Surgical morbidity and extent of resection will always be influenced 

by experience. The current work represents preeminent surgeons 

in both endoscopic and microsurgical surgery, and serves as 

testimony of the difficulty in defining either method as superior. At 

this time, the best management scheme for colloid cyst resection is 

defined by surgeon ability, equipment availability, and symptom 

presentation. With that being said, the recognized benefits of endoscopic 

surgery demand that the technique continue to be refined 

such that the ultimate outcome is as good as or better than conventional 

surgical techniques. 

Mark M. Souweidane 

New York, New York 

The authors retrospectively compare their institution’s results of 

open microsurgical resection versus endoscopic resection for colloid 

cysts. Although several studies have addressed this topic, this is one of 

the largest series and comes out of an institution with expertise in both 

techniques. Despite the large number of patients in this series, the issue 

of which procedure is best has not been completely resolved. The comparison 

is compromised by its retrospective analysis, inclusion of multiple 

surgeons, and a limited follow-up period. The overall high complication 

rate of 36% underscores the precarious nature of these lesions 


HORN ET AL. 

and why a strong argument can be made for conservative management 

of incidental lesions. 

The comparison trade-off is between completeness of resection and 

complications. The microsurgical group had a higher incidence of infections 

(19 versus 0%) and need for shunting (19 versus 0%). The incidence 

of neurological complications was similar in both groups (11%). 

However, the endoscopic group had a higher incidence of incomplete 

resection (47 versus 6%). Among patients with residual cysts who did 

not undergo reoperation, it is unknown whether or not additional 

intervention will be needed in the future and how this would influence 

the outcome analysis. 

It is not surprising that, among patients whose treatments were 

uncomplicated, the endoscopic group had shorter hospital and intensive 

care unit stays. As the endoscopic versus craniotomy controversy 

has evolved, it seems that endoscopic surgery is a viable option, and 

experienced endoscopic surgeons are likely to experience good outcomes. 

Surgeons not experienced in endoscopy should not be misled, 

however. Endoscopic resection of a colloid cyst requires a sophisticated 

level of expertise if favorable results are to be achieved. 

Jeffrey N. Bruce 

New York, New York 

Wilhelm Braune. 1831–1892. Topographisch-anatomischer Atlas, nach Durchschnitten an gefrornen Cadavern. Leipzig: Verlag von Veit & Comp., 

1867–1872. (Courtesy of the U.S. National Library of Medicine, National Institutes of Health, Bethesda, Maryland).

Colloid cyst Spetzler vs endoscope

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