- Email: [email protected]
Endoscopic Resection of Colloid Cysts: Use of a Dual-Instrument Technique and an Anterolateral Approach
PEER-REVIEW REPORTS
Endoscopic Resection of Colloid Cysts: Use of a Dual-Instrument Technique and an Anterolateral Approach David A. Wilson, David J. Fusco, Scott D. Wait, Peter Nakaji*
TUMOR
Key words Colloid cyst - Neuroendoscopy - Third ventricle -
Abbreviations and Acronyms CSF: Cerebrospinal fluid EVD: External ventricular drainage MRI: Magnetic resonance imaging Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Peter Nakaji, M.D. [E mail: [email protected]] Citation: World Neurosurg. (2013) 80, 5:576 583. http://dx.doi.org/10.1016/j.wneu.2012.07.014 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878 8750/$ see front matter ª 2013 Elsevier Inc. All rights reserved.
- OBJECTIVE:
Endoscopic approaches are increasingly utilized to treat third ventricular colloid cysts but have been associated with lower rates of complete cyst wall resection. Our objective was to assess the results of colloid cyst resection via an anterolateral endoscopic approach with a dual-instrument technique, with an emphasis on completeness of cyst wall resection.
- METHODS:
A retrospective review of the senior author’s experience with 22 colloid cysts treated with endoscopic resection since 2004 was performed. Initial cyst size, completeness of resection, postoperative radiographic residual, recurrence at follow-up, need for reoperation, and neurologic morbidity were assessed. All cysts were approached from an anterolateral trajectory with two instruments working in concert through a single endoscope.
- RESULTS:
Of 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent reresection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved.
- CONCLUSION:
INTRODUCTION Colloid cysts are rare benign lesions that account for 0.5%e2% of all intracranial tumors (2). They are typically located at the roof of the third ventricle near the foramen of Monro (3, 19). By interfering with cerebrospinal fluid (CSF) flow, colloid cysts may present with signs and symptoms of hydrocephalus and, rarely, sudden death (5, 9, 23). Surgical resection is recommended for colloid cysts that are large, symptomatic, or associated with hydrocephalus, whereas close observation may be considered for small asymptomatic lesions (24, 25). The surgical treatment of colloid cysts has evolved substantially in recent years. Traditionally, transcortical or transcallosal microsurgical approaches have been utilized for colloid cyst resection (11, 15, 20, 30). Increasingly, less invasive endoscopic approaches are employed to address these lesions in an effort to minimize perioperative morbidity (1, 4, 6-8, 14, 26, 34). The optimal approach to colloid cysts remains controversial, with some authors reporting 100% rates of complete resection with open microsurgery and others reporting short
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High rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dualinstrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results.
hospital stays and minimal morbidity with endoscopic approaches (13, 17, 28, 29). One reported drawback of endoscopic approaches is a lower rate of complete cyst wall resection and a theoretically higher risk of cyst recurrence (4, 6, 12, 14, 27). However, an important caveat is that previous reports demonstrate a significant learning curve associated with endoscopic techniques (4, 14). For this reason, earlier endoscopic series may report lower rates of complete resection than are achievable via endoscopic approaches today. In the largest report comparing open microsurgery to endoscopic resection of colloid cysts, our institution previously compared the radiographic and clinical outcomes of these two approaches based on our experience treating colloid cysts prior to 2004 (16). In that report, the endoscopic approach was associated with a 48% rate of
incomplete cyst resection and an 11% rate of repeat resection. Since that time, as our experience has grown, the senior author of this study (P.N.) has adopted a bimanual, dual-instrument endoscopic technique using an anterolateral approach to the ventricular system in all patients undergoing endoscopic removal of colloid cysts. Here, we report our results since 2004 utilizing this approach, reflecting a point further along the learning curve of endoscopic techniques with an emphasis on completeness of cyst wall resection. METHODS We retrospectively reviewed the charts of patients undergoing endoscopic colloid cyst resection at our institution since May 2004, when we adopted the dual-instrument endoscopic technique. The study period
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ENDOSCOPIC COLLOID CYST RESECTION
Grade I
No surgical or radiographic residualy
Grade II
Residual cyst wall visible to surgeon, not visible radiographicallyy
Grade III
Residual cyst visible to surgeon and radiographicallyy
Grade IV
Removal of cyst contents only or no removal
TUMOR
Table 1. Barrow Neurological Institute Grading Scale of Colloid Cyst Removal*
*Degree of colloid cyst resection based on intra operative findings and postoperative radiographic characteristics. yMRI is the preferred imaging modality to assess radiographic residual. Used with Permission from Barrow Neurological Institute.
concluded in May 2009. During this 5-year period, 22 patients underwent endoscopic resection by the senior author. The following clinical data were collected for each patient: age, gender, preoperative symptoms, presence of hydrocephalus pre- and postoperatively, pre- and postoperative neurologic deficits, need for ventriculoperitoneal shunt placement, length of stay, and infection rate. Radiographic variables evaluated included preoperative ventriculomegaly, colloid cyst diameter, presence of radiographic residual immediately after surgery and at follow-up, and cyst recurrence at follow-up. Intraoperative variables investigated included operative time, side of endoscopic approach, completeness of cyst wall resection based both on surgeon impression and postoperative radiographic findings, and intraoperative complications.
Completeness of Resection To account for the fact that some instances of residual cyst wall will be apparent intraoperatively but not on magnetic resonance image (MRI), we graded completeness of cyst resection according to a new scale that accounts for radiographically occult residual (Table 1). According to this scale, a grade I resection represents a complete resection based on intraoperative findings and postoperative MRI. A grade II resection represents a small portion of residual wall visible to the surgeon but not apparent on MRI. A grade III resection represents residual cyst wall that is apparent on MRI. Finally,
Figure 1. Anterolateral trajectory to third ventricular colloid cyst. An image guidance snapshot (A) demonstrates the anterolateral trajectory, tangential to the caudate head, used to approach a colloid cyst. The endoscopic view provided by this angle of approach (B) offers a more perpendicular trajectory to the foramen of Monro and a direct view, under the ipsilateral fornix, of the point of attachment of the colloid cyst to the roof of the third ventricle. (Used with permission from Barrow Neurological Institute.)
a grade IV resection represents an intentional subtotal removal. Operative Technique Each patient was intubated under general anesthesia and placed in a three-point Mayfield head fixation frame. In each case, the head was fixed in a flexed position with the sagittal plane perpendicular to the floor. A preoperative stereotactic brain magnetic resonance imaging (MRI) or
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computed tomography was registered to the patient’s head utilizing a StealthStation Treon unit (Medtronic Navigation). Image guidance was used to identify the optimal point of entry and trajectory in all patients. This point was typically about 5 cm anterior to the coronal suture (8 cm behind the nasion) and 5e7 cm lateral to midline, depending on the degree of ventriculomegaly present. In general, we chose the most anterolateral trajectory that
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TUMOR Figure 2. Photograph of equipment used in dual instrument technique. A view of the distal end of a 30 degree endoscope demonstrates an endoscopic bipolar in the traditional straight working channel and a bent flexible pediatric forceps in the side channel. Use of a bent instrument allows grasped structures to be placed under gentle tension as they are cauterized or cut. Straight endoscopic scissors can also be placed in the traditional channel and used in concert with the bent pediatric grasper. (Used with permission from Barrow Neurological Institute.)
did not violate the caudate head in order to provide the best angle of attack to the point of attachment of the colloid cyst to the roof of the third ventricle (Figure 1A and B). A right-sided approach was favored and used in 20 cases (91%). In 2 cases (9%), a left-sided approach was chosen because of ventricular asymmetry and lesion location predominantly on the left. Intraoperatively, a 30-degree rigid endoscope was passed into the frontal horn of the lateral ventricle under stereotactic guidance. Cyst resection proceeded without CSF aspiration and under gentle intermittent hand-pump irrigation with lactated Ringer solution. Cysts were initially coagulated with bipolar electrocautery, then punctured and aspirated utilizing a pediatric endotracheal suction catheter (31). Following aspiration, a dual-instrument technique was used to resect the cyst wall, with a flexible pediatric grasping forceps placed in a side-channel of the endoscope and a second instrument in the traditional straight working channel (Figure 2). The surgeon performed resection in a bimanual fashion, with one hand controlling each instrument, while an assistant held the endoscope. The small forceps was used to grasp the cyst so that scissors or bipolar could be applied under tension. Using this dual-instrument technique, cyst walls were
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Figure 3. Dual instrument endoscopic technique. Utilizing a flexible pediatric endoscopic grasping forceps in concert with an additional endoscopic instrument, the colloid cyst wall is placed under gentle traction and cauterized with an endoscopic bipolar (A and B), or sharply dissected from the fornices (C and D). (Used with permission from Barrow Neurological Institute.)
resected with a combination of gentle traction, coagulation, and sharp dissection (Figure 3AeD). In 21 cases (95%), the preoperative goal was complete cyst wall resection. In one case (5%), the preoperative goal was only biopsy and subtotal decompression because of the presence of significant medical comorbidities. RESULTS During the study period, 22 patients underwent an endoscopic approach for colloid cyst resection. Median age at presentation was 47 years (range 22e72 years). The most common presenting symptom was headache (12 patients), followed by altered level of consciousness (5 patients), ataxia or gait instability (6 patients), and memory difficulties (2 patients). The colloid cyst was discovered incidentally in 3 patients. Two patients presented with sudden decline in level of consciousness. Nineteen patients
had radiographic ventriculomegaly on presentation (86%). Median preoperative cyst diameter was 1.2 cm (range 0.6e2.2 cm). Preoperative patient characteristics are listed in Table 2. A right frontal approach was performed in 20 patients (91%) and a left-frontal approach was chosen in 2 patients (9%). Mean operative time was 180.4 minutes. The degree of colloid cyst removal was assigned a grade based on intraoperative and radiographic features as shown in Table 2. A grade I (complete cyst wall) resection was achieved in 18 patients (82%) based on surgeon’s impression. Of the 4 subtotal resections, a very small portion of radiographically occult residual cyst wall (grade II resection) was left in 3 cases because it was adherent to the fornix or wall of the third ventricle. This yields a total or near-total resection rate of 95% (21 of 22 patients). In the fourth subtotal resection case, which constitutes a grade IV removal, the operative goal was biopsy and
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ENDOSCOPIC COLLOID CYST RESECTION
Table 2. Preoperative Demographic and Radiographic Information for Patients Undergoing Endoscopic Colloid Cyst Resection
Gender (M:F)
47 (22e72)
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Age (median [range]), years
14:8
Presentation (% [n/total n]) Headache
57 (12/22)
ALOC
23 (5/22)
Memory dysfunction
9 (2/22)
Other neurologic sign
27 (6/22)
Incidental
14 (3/22)
Cyst diameter (median [range]), cm 1.2 (0.6e2.2) Ventriculomegaly (% [n/total n])
86 (19/22)
M, male; F, female; ALOC, altered level of consciousness. Used with permission from Barrow Neurological Institute.
internal debulking of a large cyst to manage hydrocephalus in a patient with significant medical comorbidities. Postoperative imaging demonstrated radiographic residual only in the one patient who underwent intentional subtotal resection (Figure 4). External ventricular drainage was utilized in 17 patients (77%), and 4 patients (18%) ultimately required placement of a ventriculoperitoneal shunt. All patients who required shunts had hydrocephalus on presentation and failed a postoperative attempt at ventriculostomy weaning despite apparently patent ventricular systems. The degree of ventriculomegaly was smaller in 9 patients (41%) and stable in 13 (59%) on postoperative imaging. On discharge, 13 patients (59%) demonstrated subjective improvement in presenting symptoms and 9 patients (41%) had no change in the severity or frequency of presenting symptoms. There were no instances of wound infection or ventriculitis following surgery. There were no cases of intraventricular hemorrhage following endoscopy. One patient experienced an acute subdural hematoma requiring craniotomy following emergent external ventricular drain placement on admission and subsequently underwent endoscopic colloid cyst resection 4 days later. Sixteen patients (73%) were available for a mean follow-up of 19.8 months. At this time, 15 (94%) reported improved or resolved symptoms. One patient (6%)
Figure 4. Residual cyst wall. A large colloid cyst (A) in an elderly patient was fenestrated and emptied without an attempt to dissect the cyst from the fornices. The residual cyst wall can be seen in B (arrow). Only large pieces of residual cyst wall can be seen on MRI. (Used with permission from Barrow Neurological Institute.)
experienced subjective worsening in memory function at follow-up after experiencing initial improvement in nausea and headache and demonstrating intact memory on discharge. Two patients died during the study period; one patient died 6 months following surgery due to an unrelated stroke, and one patient died 9 months following surgery due to metastatic disease. Seventeen patients (77%) had long-term radiographic follow-up over a mean of 14.3 months. No patients demonstrated radiographic evidence of cyst recurrence over the follow-up period. One patient did demonstrate evidence of a trapped ventricle 1 month following surgery in the absence of recurrence and required shunt placement. There were no instances of reoperation for cyst re-resection during the follow-up period. Surgical and follow-up data are listed in Table 3. DISCUSSION One of the principal concerns about the use of endoscopy for the removal of colloid cysts is a purported higher rate of residual cyst versus open techniques (Table 4) (4, 6, 10, 12, 14, 27). The reason usually cited is the lack of ability to carry out the fine dissection typically available to the microsurgeon. In our experience, a high rate of complete or near-complete cyst resection has been possible. In this series, we
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achieved an 82% rate of complete cyst wall resection, and a 95% rate of complete or near-complete resection, with no recurrences during follow-up and no need to convert any cases to an open craniotomy. These results contrast with our experience prior to 2004 in which nearly half of all patients treated endoscopically had incomplete cyst resections and 2 patients required additional treatment via an open approach. In our estimation, the factors that contribute most strongly to our improved endoscopic results are 1) the use of the anterolateral approach, which allows a direct view of the attachment point of the cyst on the roof of the third ventricle, and 2) the use of a dualinstrument technique, in which the two instruments are bimanually manipulated in concert to allow for microdissection. This anterolateral dual-instrument approach is similar to that described by Greenlee et al. (12). Our improved results after the adoption of this technique are indicative of the learning curve associated with endoscopy and an example of how technical modifications made through increased experience may lead to higher rates of complete resection. The anterolateral approach provides a significant advantage over the traditional Kocher’s point approach (usually cited as 1 cm anterior to the coronal suture and 3 cm lateral to the midline). The Kocher’s point approach views the fornix from above and
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the fornix can be preserved. If the working channels are maintained at the superior margin of the 30 degree endoscope, the cyst attachment point at the roof of the third ventricle can be easily dissected and subsequently inspected for residual without the need for forniceal manipulation. We have used the caudate head as a guide for the lateral limit of our approach. In patients with hydrocephalus, this limit is often as far as 7 cm lateral to midline (following the curvature of the scalp with a flexible ruler). Although the consequences of caudate injury are not clear, every effort is made to achieve the most lateral trajectory without transiting the caudate head. The rightsided approach was chosen as often as possible since on the left this trajectory is not very far from the presumed location of Broca’s area for speech production. Dysphasia was not seen in this series. The bimanual, dual-instrument technique was adopted out of frustration with the inability to perform true dissection with the endoscope. In a channel endoscope, the instruments come out in straight lines, making it hard to place structures under tension as is commonly done in microsurgery. This is overcome in endoscopy by using a slightly bent instrument in the side channel that can then be rotated. Complex movements of the endoscopic instruments, including rotation and pulling of the side channel instrument after the cyst wall is gripped, can be used to place the cyst wall under tension for the scissors or bipolar in the traditional straight channel. This provides much more satisfying control than
Table 3. Procedural, Postoperative, and Follow-Up Variables* Operative time (mean SD)
180.4 65 min
Degree of resection (surgeon impression)
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Complete (BNI grade I)
82 (18/22)
Near complete (BNI grade II)
14 (3/22)
Subtotal (BNI grade III/IV) Radiographic residual y
5 (1/22) 5 (1/22) 18 (4/22)
VPS
Infection
0 (0/22)
IVH
0 (0/22)
Reoperation
0 (0/22)
Radiographic recurrence at follow up
0 (0/17)
Clinical status at follow up Improved Worse
94 (15/16) 6 (1/16)
SD, standard deviation; BNI, Barrow Neurological Institute; VPS, ventriculoperitoneal shunt; IVH, intraventricular hemorrhage. *Values are % (n/total n), unless otherwise noted. yAll patients requiring VPS had preoperative hydro cephalus. The BNI grade is as defined in Table 1. Used with permission from Barrow Neurological Institute.
approaches the cyst wall obliquely. From this trajectory, a rigid endoscope cannot offer a direct view of the cyst attachment point without violation of the fornix. Using an anterolateral trajectory, the foramen of Monro is approached perpendicularly and
simply grasping and pulling with a single instrument, and we feel it reduces the attendant morbidity associated with endoscopic dissection. Furthermore, fewer sideto-side movements are needed with the endoscope, reducing the trauma associated with “windshield-wiping” movements in the brain. It is not clear what the exact elastic tolerance of the brain is, but it is clear that it can easily be exceeded. The complete resection rate in our series compares favorably with most other endoscopic series, with a morbidity rate comparable to prior reports (1, 4, 6, 14, 16). Although we removed the entire cyst wall in 82% of our patients, Hellwig et al. reported that portions of cyst wall were left behind in all patients in their series, although only one experienced true recurrence (14). In a recent review of 90 cases of endoscopically treated colloid cysts, Boogaarts et al. reported a 42.5% rate of residual cysts immediately following surgery, a 46.9% rate of cyst persistence or recurrence at follow-up, and a 9.4% reoperation rate (4). Notably, the rate of complete cyst resection in that series increased dramatically over time as the authors gained experience with endoscopic techniques. This trend toward higher rates of complete endoscopic resection over time is indicative of the learning curve associated with endoscopic techniques and reflects that compared with open microsurgery, endoscopy is a more nascent innovation whose full potential may not be captured by earlier studies. For this reason, any meaningful comparison between open microsurgery and endoscopy
Table 4. Retrospective Studies Comparing Open Microsurgical to Endoscopic Treatment of Colloid Cysts Number of Patients
Reported Rate of Complete Cyst Resection (%)
Residual Cyst Requiring Retreatment (%)
Recurrence Rate (%)
Length of Stay (days)
Operative or Neurologic Complications (%)
Horn et al., 2007 (16)
Open: 27 Endo: 28
Open: 94 Endo: 53
Open: 0 Endo: 7
Open: 0 Endo: 0
Open: 6.3 Endo: 5.4
Open: 33 Endo: 13
Stachura et al., 2009 (32)
Open: 13 Endo: 10
Open:100 Endo: 60
Open: 0 Endo: 10
NA NA
NA NA
Open: 38 Endo: 30
Grondin et al., 2007 (13)
Open: 9 Endo: 25
Open:100 Endo: 96
Open: 0 Endo: 0
Open: 11 Endo: 4
Open: 8.4 Endo: 3.8
Open: 33 Endo: 4
Kehler et al., 2001 (17)
Open: 10 Endo: 10
Open: 80 Endo: 30
NA NA
Open: 0 Endo: 10
Open:18.9 Endo: 5.1
Open: 50 Endo: 30
Lewis et al., 1994 (18)
Open: 8 Endo: 7
NA NA
NA NA
NA NA
Open: 9.5 Endo: 4
Open: 63 Endo: 14
Reference
Open, open microsurgical approach; Endo, endoscopic approach; NA, data not assessed by the study. Used with permission from Barrow Neurological Institute.
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Table 5. Recent Retrospective Series of Colloid Cysts Resected via an Endoscopic Approach Number of Patients
Reported Rate of Complete Cyst Resection (%)
Recurrence Rate (%)
Permanent Morbidity (%)
Boogaarts et al., 2011 (4)
85
57.5
7
1
Engh et al., 2010 (10)
47
97
NA
0
Reference
Mishra et al., 2010 (22)
59
78
0
2
Greenlee et al., 2008 (12)
35
83*
3
0
Hellwig et al., 2003 (14)
29
0
5
10
NA, not assessed by the study. *Six patients required conversion to open approach. Used with permission from Barrow Neurological Institute.
should emphasize the most recent endoscopic outcomes (Tables 5 and 6). Our experience points to an additional potential pitfall in comparing rates of complete cyst resection between open and endoscopic series: not all residual disease is apparent on MRI. In our series, three of the four cases of residual cyst were noticed by the surgeon intraoperatively but remained undetectable on MRI, both immediately following surgery and at last follow-up. In one of the strongest recent series favoring an open microsurgical approach to colloid cysts, Shapiro et al. also noted the presence of small radiographically occult residuals (29). In that series, the authors report a 100% rate of radiographically confirmed complete resection. However, they also note that in 6 (11%) cases, a small portion of residual cyst wall was left and coagulated. Although the potential for such small residuals to cause recurrence is not known, the discrepancy between any residual and radiographically-apparent residual calls for a more clear definition of complete resection.
To address this ambiguity, we developed a grading scale to define completeness of resection that includes a category for known residual that is radiographically occult (Table 1). When applying this scale, the grade I (no residual at all) resection rate was 82% in our series and 89% in the open series by Shapiro et al. (29). When including grade II (radiographically occult residual) resections, the rates were 95% and 100%, respectively. By accounting for the presence of radiographically occult residual, our scale makes this clear and direct comparison across studies feasible. Currently, the degree of colloid cyst resection reported in studies is unstandardized, with some series relying on MRI to define complete resection and others relying on intraoperative findings (13, 29). In some studies, the criteria for complete resection are not stated (28). For these reasons, a standardized scale, such as ours, that clearly defines completeness of resection, both radiographically and based on intraoperative findings, is necessary for different techniques and results to be
Table 6. Recent Retrospective Series of Colloid Cysts Resected via an Open Microsurgical Approach Number of Patients
Reported Rate of Complete Cyst Resection (%)
Recurrence Rate (%)
Permanent Morbidity (%)
Symss et al., 2011 (33)
78
99
3
NA
Sampath et al., 2010 (28)
10
100
0
20
Shapiro et al., 2009 (29)
57
100
0
0
Reference
NA, not assessed by the study. Used with permission from Barrow Neurological Institute.
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compared and followed in a more meaningful fashion. Our series supports other recent reports demonstrating that endoscopic approaches offer effective treatment of colloid cysts with low morbidity (4, 10, 14). Although detailed neuropsychological testing was not performed, we assessed memory through standard neurologic examination and close clinical questioning. Although forniceal trauma was not specifically recorded, forniceal preservation is generally improved using a bimanual anterolateral approach because the cyst can be dissected off the fornices sharply rather than by cautery or simple traction. Clinically, 94% of patients reported resolved or significantly improved symptoms at follow-up, with one patient reporting subjective worsening of memory. Although our follow-up is too short to comment on long-term recurrence, no early recurrence was seen during our follow-up period. Other features of our series deserve mention. Our rate of external ventricular drainage (EVD) (77%) and ventriculoperitoneal shunting (18%) is higher than in other series. The high rate of external ventricular drainage may reflect a low threshold for placing an EVD in a patient admitted through the emergency room with ventriculomegaly, a colloid cyst and new or progressive neurologic symptoms. In nine cases (41%), single or bilateral EVDs were placed semi-emergently on admission in the context of progressive neurologic symptoms and ventriculomegaly. In one case (5%), an EVD was placed at an outside hospital prior to transfer to our institution. In one other case (5%), a ventriculoperitoneal shunt was placed at an outside hospital prior to transfer. In that case, after colloid cyst resection, the shunt was removed and replaced with a temporary EVD for monitoring purposes. In six cases, a new EVD was placed temporarily at the conclusion of surgery through the endoscope sheath. In the absence of elevated intracranial pressure, these EVDs were removed 1 to 2 days following surgery. Overall, four patients required shunting: one patient with multiple medical comorbidities and hydrocephalus had an intentional subtotal cyst resection and required a shunt, one patient re-presented 1 month after successful EVD weaning with a trapped temporal horn requiring a shunt, and two
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patients were shunted because of an inability to successfully wean their EVDs following complete cyst resection. Although one patient was treated with intentional cyst decompression rather than complete resection, we do not advocate this strategy as a first-line treatment of colloid cysts. This patient was elderly, with multiple medical issues, including a recent stroke, with hydrocephalus. The primary goal of treatment in this case was decompression of the foramen of Monro. Ultimately, however, this patient did require a shunt. In general, the role of biopsy and subtotal decompression of colloid cysts is not substantiated and is associated with higher rates of recurrence (21). For this reason, unless there is a serious medical contraindication to a more lengthy operation, complete cyst removal should be the surgical goal. The four cases (18%) of incomplete cyst removal highlight the difficulties that may be encountered with an endoscopic approach. Aside from the one intentional subtotal resection described above, resection was limited by adherence of the cyst wall to the body of the fornix in two cases and to the walls of the third ventricle in one case. The residuals in the latter three cases were small and radiographically occult. When comparing results across series, it is worth noting that other authors have classified such cases as complete resections and that cyst adherence to critical structures also presents a challenge in open approaches (13, 29). This study is limited by its retrospective design. Although the follow-up is short, the length of follow-up is comparable to other reports. Longer-term follow-up over a 5- to 10-year period will be necessary to accurately assess recurrence rates. Although the number of patients is small, it is similar to those reported in prior endoscopic series. It is not possible to validate the value of our anterolateral approach using the data we provide; no control group is available of those who had similar surgery from a more traditional trajectory and entry point. Additionally, since no attempt was made to treat some patients with a single instrument technique, there is no comparison group in this regard. Realistically, such a trial is not possible. Nonetheless, we believe we provide a sound rationale for the value of an anterolateral, dual-
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instrument endoscopic approach that is supported by favorable outcomes compared to reported historical data and our own previously published results (16). CONCLUSIONS An anterolateral approach for endoscopic resection of colloid cysts using a dualinstrument technique provides favorable results with respect to completeness of cyst removal, and a similar morbidity rate, when compared to historically reported results. Our improved results compared to our prior experience reflect the learning curve associated with endoscopic techniques. In addition, our review of the literature demonstrates the need for a standardized scale to grade completeness of colloid cyst resection. REFERENCES 1. Abdou MS, Cohen AR: Endoscopic treatment of colloid cysts of the third ventricle: Technical note and review of the literature. J Neurosurg 89: 1062-1068, 1998. 2. Antunes JL, Louis KM, Ganti SR: Colloid cysts of the third ventricle. Neurosurgery 7:450-455, 1980. 3. Batnitzky S, Sarwar M, Leeds NE, Schechter MM, zar-Kia B: Colloid cysts of the third ventricle. Radiology 112:327-341, 1974. 4. Boogaarts HD, Decq P, Grotenhuis JA, Le GC, Nseir R, Jarraya B, Djindjian M, Beems T: Longterm results of the neuroendoscopic management of colloid cysts of the third ventricle: a series of 90 cases. Neurosurgery 68:179-187, 2011. 5. 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. 6. Decq P, Le GC, Brugieres P, Djindjian M, Silva D, Keravel Y, Melon E, Nguyen JP: Endoscopic management of colloid cysts. Neurosurgery 42: 1288-1294, 1998. 7. Deinsberger W, Boker DK, Bothe HW, Samii M: Stereotactic endoscopic treatment of colloid cysts of the third ventricle. Acta Neurochir (Wien) 131: 260-264, 1994. 8. Deinsberger W, Boker DK, Samii M: Flexible endoscopes in treatment of colloid cysts of the third ventricle. Minim Invasive Neurosurg 37: 12-16, 1994. 9. Desai KI, Nadkarni TD, Muzumdar DP, Goel AH: Surgical management of colloid cyst of the third ventricle a study of 105 cases. Surg Neurol 57: 295-302, 2002. 10. Engh JA, Lunsford LD, Amin DV, Ochalski PG, Fernandez-Miranda J, Prevedello DM, Kassam AB:
Stereotactically guided endoscopic port surgery for intraventricular tumor and colloid cyst resection. Neurosurgery 67:ons198-ons204, 2010. 11. Gokalp HZ, Yuceer N, Arasil E, Erdogan A, Dincer C, Baskaya M: Colloid cyst of the third ventricle: Evaluation of 28 cases of colloid cyst of the third ventricle operated on by transcortical transventricular (25 cases) and transcallosal/ transventricular (3 cases) approaches. Acta Neurochir (Wien) 138:45-49, 1996. 12. Greenlee JD, Teo C, Ghahreman A, Kwok B: Purely endoscopic resection of colloid cysts. Neurosurgery 62:51-55, 2008. 13. Grondin RT, Hader W, MacRae ME, Hamilton MG: Endoscopic versus microsurgical resection of third ventricle colloid cysts. Can J Neurol Sci 34:197-207, 2007. 14. Hellwig D, Bauer BL, Schulte M, Gatscher S, Riegel T, Bertalanffy H: Neuroendoscopic treatment for colloid cysts of the third ventricle: the experience of a decade. Neurosurgery 52:525-533, 2003. 15. 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. 16. Horn EM, Feiz-Erfan I, Bristol RE, Lekovic GP, Goslar PW, Smith KA, Nakaji P, Spetzler RF: Treatment options for third ventricular colloid cysts: comparison of open microsurgical versus endoscopic resection. Neurosurgery 60:613-618, 2007. 17. Kehler U, Brunori A, Gliemroth J, Nowak G, Delitala A, Chiappetta F, Arnold H: Twenty colloid cysts comparison of endoscopic and microsurgical management. Minim Invasive Neurosurg 44: 121-127, 2001. 18. Lewis AI, Crone KR, Taha J, van Loveren HR, Yeh HS, Tew JM Jr: Surgical resection of third ventricle colloid cysts: Preliminary results comparing transcallosal microsurgery with endoscopy. J Neurosurg 81:174-178, 1994. 19. Little JR, MacCarty CS: Colloid cysts of the third ventricle. J Neurosurg 40:230-235, 1974. 20. Mathiesen T, Grane P, Lindgren L, Lindquist C: Third ventricle colloid cysts: a consecutive 12-year series. J Neurosurg 86:5-12, 1997. 21. 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. 22. Mishra S, Chandra PS, Suri A, Rajender K, Sharma BS, Mahapatra AK: Endoscopic management of third ventricular colloid cysts: eight years’ institutional experience and description of a new technique. Neurol India 58:412-417, 2010. 23. Nitta M, Symon L: Colloid cysts of the third ventricle: A review of 36 cases. Acta Neurochir (Wien) 76:99-104, 1985.
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24. Pollock BE, Huston J III: Natural history of asymptomatic colloid cysts of the third ventricle. J Neurosurg 91:364-369, 1999. 25. Pollock BE, Schreiner SA, Huston J III: A theory on the natural history of colloid cysts of the third ventricle. Neurosurgery 46:1077-1081, 2000. 26. Powell MP, Torrens MJ, Thomson JL, Horgan JG: Isodense colloid cysts of the third ventricle: a diagnostic and therapeutic problem resolved by ventriculoscopy. Neurosurgery 13:234-237, 1983. 27. Rodziewicz GS, Smith MV, Hodge CJ Jr: Endoscopic colloid cyst surgery. Neurosurgery 46: 655-660, 2000. 28. Sampath R, Vannemreddy P, Nanda A: Microsurgical excision of colloid cyst with favorable cognitive outcomes and short operative time and hospital stay: operative techniques and analyses of outcomes with review of previous studies. Neurosurgery 66:368-374, 2010.
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29. Shapiro S, Rodgers R, Shah M, Fulkerson D, Campbell RL: Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle. J Neurosurg 110:112-115, 2009. 30. Shucart WA, Stein BM: Transcallosal approach to the anterior ventricular system. Neurosurgery 3: 339-343, 1978. 31. Souweidane MM, Luther N: Endoscopic resection of solid intraventricular brain tumors. J Neurosurg 105:271-278, 2006. 32. Stachura K, Libionka W, Moskala M, Krupa M, Polak J: Colloid cysts of the third ventricle: Endoscopic and open microsurgical management. Neurol Neurochir Pol 43:251-257, 2009.
ventricle: an analysis of 78 cases. Neurol India 59: 542-547, 2011. 34. Teo C: Complete endoscopic removal of colloid cysts: issues of safety and efficacy. Neurosurg Focus 6:e9, 1999.
Conflict of interest statement: Dr. Peter Nakaji serves on the Medtronic Navigation scientific advisory board. The remaining authors have neither conflicts of interest nor financial interests to disclose. Received 20 December 2011; accepted 25 July 2012; published online 28 July 2012 Citation: World Neurosurg. (2013) 80, 5:576-583. http://dx.doi.org/10.1016/j.wneu.2012.07.014 Journal homepage: www.WORLDNEUROSURGERY.org
33. Symss NP, Ramamurthi R, Rao SM, Vasudevan MC, Jain PK, Pande A: Management outcome of the transcallosal, transforaminal approach to colloid cysts of the anterior third
Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2013 Elsevier Inc. All rights reserved.
Endoscopic Endonasal Transmaxillary Approach and Endoscopic Sublabial Transmaxillary Approach: Surgical Decision-Making and Implications of the Nasolacrimal Duct Andrew S. Little1, Peter Nakaji1, John Milligan2
Key words Caldwell-Luc - Endoscope - Skull Base Tumors - Transmaxillary Approach -
Abbreviations and Acronyms SEND: Septal nasolacrimal duct line From 1Barrow Neurological Institute, Division of Neurological Surgery, St Joseph's Hospital and Medical Center, Phoenix, Arizona; and 2Arizona Otolaryngology Consultants, Phoenix, Arizona, USA To whom correspondence should be addressed: Andrew S. Little, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2013) 80, 5:583-590. http://dx.doi.org/10.1016/j.wneu.2012.01.059 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2013 Elsevier Inc. All rights reserved.
INTRODUCTION The pterygopalatine and infratemporal fossae are relatively uncommon sites of skull base pathology such as chordomas, infection, juvenile angiofibromas, and schwannomas. These lesions can be technically challenging to reach because of their deep location and proximity to critical neurovascular structures. There has been a trend
- BACKGROUND:
The nasolacrimal duct resides in the wall of the medial nasal cavity and influences minimal access endoscopic transmaxillary approaches to the lateral skull base. We describe an algorithm for surgical approach selection on the basis of the relationship of the target lesion to a line drawn from the anterior nasal SEptum through the Nasolacrimal Duct to the lesion (i.e., SEND line).
- METHODS:
We use the SEND line to estimate the lateral extent in the endonasal middle meatal transmaxillary approach, where the surgeon has good surgical freedom without the use of angled instruments and endoscopes. Lesions with an epicenter lateral to the SEND line were addressed through a sublabial anterior antrostomy transmaxillary corridor. Tumors with a more medially located epicenter, such as those involving the lateral sphenoid sinus and pterygoid plates, were addressed through the endonasal middle meatal corridor. Extensive tumors involving both domains were addressed through a combination approach.
- RESULTS:
We describe three instructive cases in which the approach selection was determined in part by preoperative assessment of the location of the tumor relative to the SEND line.
- CONCLUSIONS:
The endoscopic sublabial transmaxillary and endoscopic endonasal middle meatal transmaxillary approaches are complementary corridors to the anterior skull base that can be used independently or in combination. The location of the target lesion relative to the SEND line as determined on preoperative imaging can serve as a guide for surgical decision making.
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DAVID A. WILSON ET AL.
Endoscopic Resection of Colloid Cysts: Use of a Dual-Instrument Technique and an Anterolateral Approach David A. Wilson, David J. Fusco, Scott D. Wait, Peter Nakaji*
TUMOR
Key words Colloid cyst - Neuroendoscopy - Third ventricle -
Abbreviations and Acronyms CSF: Cerebrospinal fluid EVD: External ventricular drainage MRI: Magnetic resonance imaging Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Peter Nakaji, M.D. [E mail: [email protected]] Citation: World Neurosurg. (2013) 80, 5:576 583. http://dx.doi.org/10.1016/j.wneu.2012.07.014 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878 8750/$ see front matter ª 2013 Elsevier Inc. All rights reserved.
- OBJECTIVE:
Endoscopic approaches are increasingly utilized to treat third ventricular colloid cysts but have been associated with lower rates of complete cyst wall resection. Our objective was to assess the results of colloid cyst resection via an anterolateral endoscopic approach with a dual-instrument technique, with an emphasis on completeness of cyst wall resection.
- METHODS:
A retrospective review of the senior author’s experience with 22 colloid cysts treated with endoscopic resection since 2004 was performed. Initial cyst size, completeness of resection, postoperative radiographic residual, recurrence at follow-up, need for reoperation, and neurologic morbidity were assessed. All cysts were approached from an anterolateral trajectory with two instruments working in concert through a single endoscope.
- RESULTS:
Of 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent reresection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved.
- CONCLUSION:
INTRODUCTION Colloid cysts are rare benign lesions that account for 0.5%e2% of all intracranial tumors (2). They are typically located at the roof of the third ventricle near the foramen of Monro (3, 19). By interfering with cerebrospinal fluid (CSF) flow, colloid cysts may present with signs and symptoms of hydrocephalus and, rarely, sudden death (5, 9, 23). Surgical resection is recommended for colloid cysts that are large, symptomatic, or associated with hydrocephalus, whereas close observation may be considered for small asymptomatic lesions (24, 25). The surgical treatment of colloid cysts has evolved substantially in recent years. Traditionally, transcortical or transcallosal microsurgical approaches have been utilized for colloid cyst resection (11, 15, 20, 30). Increasingly, less invasive endoscopic approaches are employed to address these lesions in an effort to minimize perioperative morbidity (1, 4, 6-8, 14, 26, 34). The optimal approach to colloid cysts remains controversial, with some authors reporting 100% rates of complete resection with open microsurgery and others reporting short
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High rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dualinstrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results.
hospital stays and minimal morbidity with endoscopic approaches (13, 17, 28, 29). One reported drawback of endoscopic approaches is a lower rate of complete cyst wall resection and a theoretically higher risk of cyst recurrence (4, 6, 12, 14, 27). However, an important caveat is that previous reports demonstrate a significant learning curve associated with endoscopic techniques (4, 14). For this reason, earlier endoscopic series may report lower rates of complete resection than are achievable via endoscopic approaches today. In the largest report comparing open microsurgery to endoscopic resection of colloid cysts, our institution previously compared the radiographic and clinical outcomes of these two approaches based on our experience treating colloid cysts prior to 2004 (16). In that report, the endoscopic approach was associated with a 48% rate of
incomplete cyst resection and an 11% rate of repeat resection. Since that time, as our experience has grown, the senior author of this study (P.N.) has adopted a bimanual, dual-instrument endoscopic technique using an anterolateral approach to the ventricular system in all patients undergoing endoscopic removal of colloid cysts. Here, we report our results since 2004 utilizing this approach, reflecting a point further along the learning curve of endoscopic techniques with an emphasis on completeness of cyst wall resection. METHODS We retrospectively reviewed the charts of patients undergoing endoscopic colloid cyst resection at our institution since May 2004, when we adopted the dual-instrument endoscopic technique. The study period
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Grade I
No surgical or radiographic residualy
Grade II
Residual cyst wall visible to surgeon, not visible radiographicallyy
Grade III
Residual cyst visible to surgeon and radiographicallyy
Grade IV
Removal of cyst contents only or no removal
TUMOR
Table 1. Barrow Neurological Institute Grading Scale of Colloid Cyst Removal*
*Degree of colloid cyst resection based on intra operative findings and postoperative radiographic characteristics. yMRI is the preferred imaging modality to assess radiographic residual. Used with Permission from Barrow Neurological Institute.
concluded in May 2009. During this 5-year period, 22 patients underwent endoscopic resection by the senior author. The following clinical data were collected for each patient: age, gender, preoperative symptoms, presence of hydrocephalus pre- and postoperatively, pre- and postoperative neurologic deficits, need for ventriculoperitoneal shunt placement, length of stay, and infection rate. Radiographic variables evaluated included preoperative ventriculomegaly, colloid cyst diameter, presence of radiographic residual immediately after surgery and at follow-up, and cyst recurrence at follow-up. Intraoperative variables investigated included operative time, side of endoscopic approach, completeness of cyst wall resection based both on surgeon impression and postoperative radiographic findings, and intraoperative complications.
Completeness of Resection To account for the fact that some instances of residual cyst wall will be apparent intraoperatively but not on magnetic resonance image (MRI), we graded completeness of cyst resection according to a new scale that accounts for radiographically occult residual (Table 1). According to this scale, a grade I resection represents a complete resection based on intraoperative findings and postoperative MRI. A grade II resection represents a small portion of residual wall visible to the surgeon but not apparent on MRI. A grade III resection represents residual cyst wall that is apparent on MRI. Finally,
Figure 1. Anterolateral trajectory to third ventricular colloid cyst. An image guidance snapshot (A) demonstrates the anterolateral trajectory, tangential to the caudate head, used to approach a colloid cyst. The endoscopic view provided by this angle of approach (B) offers a more perpendicular trajectory to the foramen of Monro and a direct view, under the ipsilateral fornix, of the point of attachment of the colloid cyst to the roof of the third ventricle. (Used with permission from Barrow Neurological Institute.)
a grade IV resection represents an intentional subtotal removal. Operative Technique Each patient was intubated under general anesthesia and placed in a three-point Mayfield head fixation frame. In each case, the head was fixed in a flexed position with the sagittal plane perpendicular to the floor. A preoperative stereotactic brain magnetic resonance imaging (MRI) or
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computed tomography was registered to the patient’s head utilizing a StealthStation Treon unit (Medtronic Navigation). Image guidance was used to identify the optimal point of entry and trajectory in all patients. This point was typically about 5 cm anterior to the coronal suture (8 cm behind the nasion) and 5e7 cm lateral to midline, depending on the degree of ventriculomegaly present. In general, we chose the most anterolateral trajectory that
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TUMOR Figure 2. Photograph of equipment used in dual instrument technique. A view of the distal end of a 30 degree endoscope demonstrates an endoscopic bipolar in the traditional straight working channel and a bent flexible pediatric forceps in the side channel. Use of a bent instrument allows grasped structures to be placed under gentle tension as they are cauterized or cut. Straight endoscopic scissors can also be placed in the traditional channel and used in concert with the bent pediatric grasper. (Used with permission from Barrow Neurological Institute.)
did not violate the caudate head in order to provide the best angle of attack to the point of attachment of the colloid cyst to the roof of the third ventricle (Figure 1A and B). A right-sided approach was favored and used in 20 cases (91%). In 2 cases (9%), a left-sided approach was chosen because of ventricular asymmetry and lesion location predominantly on the left. Intraoperatively, a 30-degree rigid endoscope was passed into the frontal horn of the lateral ventricle under stereotactic guidance. Cyst resection proceeded without CSF aspiration and under gentle intermittent hand-pump irrigation with lactated Ringer solution. Cysts were initially coagulated with bipolar electrocautery, then punctured and aspirated utilizing a pediatric endotracheal suction catheter (31). Following aspiration, a dual-instrument technique was used to resect the cyst wall, with a flexible pediatric grasping forceps placed in a side-channel of the endoscope and a second instrument in the traditional straight working channel (Figure 2). The surgeon performed resection in a bimanual fashion, with one hand controlling each instrument, while an assistant held the endoscope. The small forceps was used to grasp the cyst so that scissors or bipolar could be applied under tension. Using this dual-instrument technique, cyst walls were
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Figure 3. Dual instrument endoscopic technique. Utilizing a flexible pediatric endoscopic grasping forceps in concert with an additional endoscopic instrument, the colloid cyst wall is placed under gentle traction and cauterized with an endoscopic bipolar (A and B), or sharply dissected from the fornices (C and D). (Used with permission from Barrow Neurological Institute.)
resected with a combination of gentle traction, coagulation, and sharp dissection (Figure 3AeD). In 21 cases (95%), the preoperative goal was complete cyst wall resection. In one case (5%), the preoperative goal was only biopsy and subtotal decompression because of the presence of significant medical comorbidities. RESULTS During the study period, 22 patients underwent an endoscopic approach for colloid cyst resection. Median age at presentation was 47 years (range 22e72 years). The most common presenting symptom was headache (12 patients), followed by altered level of consciousness (5 patients), ataxia or gait instability (6 patients), and memory difficulties (2 patients). The colloid cyst was discovered incidentally in 3 patients. Two patients presented with sudden decline in level of consciousness. Nineteen patients
had radiographic ventriculomegaly on presentation (86%). Median preoperative cyst diameter was 1.2 cm (range 0.6e2.2 cm). Preoperative patient characteristics are listed in Table 2. A right frontal approach was performed in 20 patients (91%) and a left-frontal approach was chosen in 2 patients (9%). Mean operative time was 180.4 minutes. The degree of colloid cyst removal was assigned a grade based on intraoperative and radiographic features as shown in Table 2. A grade I (complete cyst wall) resection was achieved in 18 patients (82%) based on surgeon’s impression. Of the 4 subtotal resections, a very small portion of radiographically occult residual cyst wall (grade II resection) was left in 3 cases because it was adherent to the fornix or wall of the third ventricle. This yields a total or near-total resection rate of 95% (21 of 22 patients). In the fourth subtotal resection case, which constitutes a grade IV removal, the operative goal was biopsy and
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Table 2. Preoperative Demographic and Radiographic Information for Patients Undergoing Endoscopic Colloid Cyst Resection
Gender (M:F)
47 (22e72)
TUMOR
Age (median [range]), years
14:8
Presentation (% [n/total n]) Headache
57 (12/22)
ALOC
23 (5/22)
Memory dysfunction
9 (2/22)
Other neurologic sign
27 (6/22)
Incidental
14 (3/22)
Cyst diameter (median [range]), cm 1.2 (0.6e2.2) Ventriculomegaly (% [n/total n])
86 (19/22)
M, male; F, female; ALOC, altered level of consciousness. Used with permission from Barrow Neurological Institute.
internal debulking of a large cyst to manage hydrocephalus in a patient with significant medical comorbidities. Postoperative imaging demonstrated radiographic residual only in the one patient who underwent intentional subtotal resection (Figure 4). External ventricular drainage was utilized in 17 patients (77%), and 4 patients (18%) ultimately required placement of a ventriculoperitoneal shunt. All patients who required shunts had hydrocephalus on presentation and failed a postoperative attempt at ventriculostomy weaning despite apparently patent ventricular systems. The degree of ventriculomegaly was smaller in 9 patients (41%) and stable in 13 (59%) on postoperative imaging. On discharge, 13 patients (59%) demonstrated subjective improvement in presenting symptoms and 9 patients (41%) had no change in the severity or frequency of presenting symptoms. There were no instances of wound infection or ventriculitis following surgery. There were no cases of intraventricular hemorrhage following endoscopy. One patient experienced an acute subdural hematoma requiring craniotomy following emergent external ventricular drain placement on admission and subsequently underwent endoscopic colloid cyst resection 4 days later. Sixteen patients (73%) were available for a mean follow-up of 19.8 months. At this time, 15 (94%) reported improved or resolved symptoms. One patient (6%)
Figure 4. Residual cyst wall. A large colloid cyst (A) in an elderly patient was fenestrated and emptied without an attempt to dissect the cyst from the fornices. The residual cyst wall can be seen in B (arrow). Only large pieces of residual cyst wall can be seen on MRI. (Used with permission from Barrow Neurological Institute.)
experienced subjective worsening in memory function at follow-up after experiencing initial improvement in nausea and headache and demonstrating intact memory on discharge. Two patients died during the study period; one patient died 6 months following surgery due to an unrelated stroke, and one patient died 9 months following surgery due to metastatic disease. Seventeen patients (77%) had long-term radiographic follow-up over a mean of 14.3 months. No patients demonstrated radiographic evidence of cyst recurrence over the follow-up period. One patient did demonstrate evidence of a trapped ventricle 1 month following surgery in the absence of recurrence and required shunt placement. There were no instances of reoperation for cyst re-resection during the follow-up period. Surgical and follow-up data are listed in Table 3. DISCUSSION One of the principal concerns about the use of endoscopy for the removal of colloid cysts is a purported higher rate of residual cyst versus open techniques (Table 4) (4, 6, 10, 12, 14, 27). The reason usually cited is the lack of ability to carry out the fine dissection typically available to the microsurgeon. In our experience, a high rate of complete or near-complete cyst resection has been possible. In this series, we
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achieved an 82% rate of complete cyst wall resection, and a 95% rate of complete or near-complete resection, with no recurrences during follow-up and no need to convert any cases to an open craniotomy. These results contrast with our experience prior to 2004 in which nearly half of all patients treated endoscopically had incomplete cyst resections and 2 patients required additional treatment via an open approach. In our estimation, the factors that contribute most strongly to our improved endoscopic results are 1) the use of the anterolateral approach, which allows a direct view of the attachment point of the cyst on the roof of the third ventricle, and 2) the use of a dualinstrument technique, in which the two instruments are bimanually manipulated in concert to allow for microdissection. This anterolateral dual-instrument approach is similar to that described by Greenlee et al. (12). Our improved results after the adoption of this technique are indicative of the learning curve associated with endoscopy and an example of how technical modifications made through increased experience may lead to higher rates of complete resection. The anterolateral approach provides a significant advantage over the traditional Kocher’s point approach (usually cited as 1 cm anterior to the coronal suture and 3 cm lateral to the midline). The Kocher’s point approach views the fornix from above and
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the fornix can be preserved. If the working channels are maintained at the superior margin of the 30 degree endoscope, the cyst attachment point at the roof of the third ventricle can be easily dissected and subsequently inspected for residual without the need for forniceal manipulation. We have used the caudate head as a guide for the lateral limit of our approach. In patients with hydrocephalus, this limit is often as far as 7 cm lateral to midline (following the curvature of the scalp with a flexible ruler). Although the consequences of caudate injury are not clear, every effort is made to achieve the most lateral trajectory without transiting the caudate head. The rightsided approach was chosen as often as possible since on the left this trajectory is not very far from the presumed location of Broca’s area for speech production. Dysphasia was not seen in this series. The bimanual, dual-instrument technique was adopted out of frustration with the inability to perform true dissection with the endoscope. In a channel endoscope, the instruments come out in straight lines, making it hard to place structures under tension as is commonly done in microsurgery. This is overcome in endoscopy by using a slightly bent instrument in the side channel that can then be rotated. Complex movements of the endoscopic instruments, including rotation and pulling of the side channel instrument after the cyst wall is gripped, can be used to place the cyst wall under tension for the scissors or bipolar in the traditional straight channel. This provides much more satisfying control than
Table 3. Procedural, Postoperative, and Follow-Up Variables* Operative time (mean SD)
180.4 65 min
Degree of resection (surgeon impression)
TUMOR
Complete (BNI grade I)
82 (18/22)
Near complete (BNI grade II)
14 (3/22)
Subtotal (BNI grade III/IV) Radiographic residual y
5 (1/22) 5 (1/22) 18 (4/22)
VPS
Infection
0 (0/22)
IVH
0 (0/22)
Reoperation
0 (0/22)
Radiographic recurrence at follow up
0 (0/17)
Clinical status at follow up Improved Worse
94 (15/16) 6 (1/16)
SD, standard deviation; BNI, Barrow Neurological Institute; VPS, ventriculoperitoneal shunt; IVH, intraventricular hemorrhage. *Values are % (n/total n), unless otherwise noted. yAll patients requiring VPS had preoperative hydro cephalus. The BNI grade is as defined in Table 1. Used with permission from Barrow Neurological Institute.
approaches the cyst wall obliquely. From this trajectory, a rigid endoscope cannot offer a direct view of the cyst attachment point without violation of the fornix. Using an anterolateral trajectory, the foramen of Monro is approached perpendicularly and
simply grasping and pulling with a single instrument, and we feel it reduces the attendant morbidity associated with endoscopic dissection. Furthermore, fewer sideto-side movements are needed with the endoscope, reducing the trauma associated with “windshield-wiping” movements in the brain. It is not clear what the exact elastic tolerance of the brain is, but it is clear that it can easily be exceeded. The complete resection rate in our series compares favorably with most other endoscopic series, with a morbidity rate comparable to prior reports (1, 4, 6, 14, 16). Although we removed the entire cyst wall in 82% of our patients, Hellwig et al. reported that portions of cyst wall were left behind in all patients in their series, although only one experienced true recurrence (14). In a recent review of 90 cases of endoscopically treated colloid cysts, Boogaarts et al. reported a 42.5% rate of residual cysts immediately following surgery, a 46.9% rate of cyst persistence or recurrence at follow-up, and a 9.4% reoperation rate (4). Notably, the rate of complete cyst resection in that series increased dramatically over time as the authors gained experience with endoscopic techniques. This trend toward higher rates of complete endoscopic resection over time is indicative of the learning curve associated with endoscopic techniques and reflects that compared with open microsurgery, endoscopy is a more nascent innovation whose full potential may not be captured by earlier studies. For this reason, any meaningful comparison between open microsurgery and endoscopy
Table 4. Retrospective Studies Comparing Open Microsurgical to Endoscopic Treatment of Colloid Cysts Number of Patients
Reported Rate of Complete Cyst Resection (%)
Residual Cyst Requiring Retreatment (%)
Recurrence Rate (%)
Length of Stay (days)
Operative or Neurologic Complications (%)
Horn et al., 2007 (16)
Open: 27 Endo: 28
Open: 94 Endo: 53
Open: 0 Endo: 7
Open: 0 Endo: 0
Open: 6.3 Endo: 5.4
Open: 33 Endo: 13
Stachura et al., 2009 (32)
Open: 13 Endo: 10
Open:100 Endo: 60
Open: 0 Endo: 10
NA NA
NA NA
Open: 38 Endo: 30
Grondin et al., 2007 (13)
Open: 9 Endo: 25
Open:100 Endo: 96
Open: 0 Endo: 0
Open: 11 Endo: 4
Open: 8.4 Endo: 3.8
Open: 33 Endo: 4
Kehler et al., 2001 (17)
Open: 10 Endo: 10
Open: 80 Endo: 30
NA NA
Open: 0 Endo: 10
Open:18.9 Endo: 5.1
Open: 50 Endo: 30
Lewis et al., 1994 (18)
Open: 8 Endo: 7
NA NA
NA NA
NA NA
Open: 9.5 Endo: 4
Open: 63 Endo: 14
Reference
Open, open microsurgical approach; Endo, endoscopic approach; NA, data not assessed by the study. Used with permission from Barrow Neurological Institute.
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Table 5. Recent Retrospective Series of Colloid Cysts Resected via an Endoscopic Approach Number of Patients
Reported Rate of Complete Cyst Resection (%)
Recurrence Rate (%)
Permanent Morbidity (%)
Boogaarts et al., 2011 (4)
85
57.5
7
1
Engh et al., 2010 (10)
47
97
NA
0
Reference
Mishra et al., 2010 (22)
59
78
0
2
Greenlee et al., 2008 (12)
35
83*
3
0
Hellwig et al., 2003 (14)
29
0
5
10
NA, not assessed by the study. *Six patients required conversion to open approach. Used with permission from Barrow Neurological Institute.
should emphasize the most recent endoscopic outcomes (Tables 5 and 6). Our experience points to an additional potential pitfall in comparing rates of complete cyst resection between open and endoscopic series: not all residual disease is apparent on MRI. In our series, three of the four cases of residual cyst were noticed by the surgeon intraoperatively but remained undetectable on MRI, both immediately following surgery and at last follow-up. In one of the strongest recent series favoring an open microsurgical approach to colloid cysts, Shapiro et al. also noted the presence of small radiographically occult residuals (29). In that series, the authors report a 100% rate of radiographically confirmed complete resection. However, they also note that in 6 (11%) cases, a small portion of residual cyst wall was left and coagulated. Although the potential for such small residuals to cause recurrence is not known, the discrepancy between any residual and radiographically-apparent residual calls for a more clear definition of complete resection.
To address this ambiguity, we developed a grading scale to define completeness of resection that includes a category for known residual that is radiographically occult (Table 1). When applying this scale, the grade I (no residual at all) resection rate was 82% in our series and 89% in the open series by Shapiro et al. (29). When including grade II (radiographically occult residual) resections, the rates were 95% and 100%, respectively. By accounting for the presence of radiographically occult residual, our scale makes this clear and direct comparison across studies feasible. Currently, the degree of colloid cyst resection reported in studies is unstandardized, with some series relying on MRI to define complete resection and others relying on intraoperative findings (13, 29). In some studies, the criteria for complete resection are not stated (28). For these reasons, a standardized scale, such as ours, that clearly defines completeness of resection, both radiographically and based on intraoperative findings, is necessary for different techniques and results to be
Table 6. Recent Retrospective Series of Colloid Cysts Resected via an Open Microsurgical Approach Number of Patients
Reported Rate of Complete Cyst Resection (%)
Recurrence Rate (%)
Permanent Morbidity (%)
Symss et al., 2011 (33)
78
99
3
NA
Sampath et al., 2010 (28)
10
100
0
20
Shapiro et al., 2009 (29)
57
100
0
0
Reference
NA, not assessed by the study. Used with permission from Barrow Neurological Institute.
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compared and followed in a more meaningful fashion. Our series supports other recent reports demonstrating that endoscopic approaches offer effective treatment of colloid cysts with low morbidity (4, 10, 14). Although detailed neuropsychological testing was not performed, we assessed memory through standard neurologic examination and close clinical questioning. Although forniceal trauma was not specifically recorded, forniceal preservation is generally improved using a bimanual anterolateral approach because the cyst can be dissected off the fornices sharply rather than by cautery or simple traction. Clinically, 94% of patients reported resolved or significantly improved symptoms at follow-up, with one patient reporting subjective worsening of memory. Although our follow-up is too short to comment on long-term recurrence, no early recurrence was seen during our follow-up period. Other features of our series deserve mention. Our rate of external ventricular drainage (EVD) (77%) and ventriculoperitoneal shunting (18%) is higher than in other series. The high rate of external ventricular drainage may reflect a low threshold for placing an EVD in a patient admitted through the emergency room with ventriculomegaly, a colloid cyst and new or progressive neurologic symptoms. In nine cases (41%), single or bilateral EVDs were placed semi-emergently on admission in the context of progressive neurologic symptoms and ventriculomegaly. In one case (5%), an EVD was placed at an outside hospital prior to transfer to our institution. In one other case (5%), a ventriculoperitoneal shunt was placed at an outside hospital prior to transfer. In that case, after colloid cyst resection, the shunt was removed and replaced with a temporary EVD for monitoring purposes. In six cases, a new EVD was placed temporarily at the conclusion of surgery through the endoscope sheath. In the absence of elevated intracranial pressure, these EVDs were removed 1 to 2 days following surgery. Overall, four patients required shunting: one patient with multiple medical comorbidities and hydrocephalus had an intentional subtotal cyst resection and required a shunt, one patient re-presented 1 month after successful EVD weaning with a trapped temporal horn requiring a shunt, and two
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patients were shunted because of an inability to successfully wean their EVDs following complete cyst resection. Although one patient was treated with intentional cyst decompression rather than complete resection, we do not advocate this strategy as a first-line treatment of colloid cysts. This patient was elderly, with multiple medical issues, including a recent stroke, with hydrocephalus. The primary goal of treatment in this case was decompression of the foramen of Monro. Ultimately, however, this patient did require a shunt. In general, the role of biopsy and subtotal decompression of colloid cysts is not substantiated and is associated with higher rates of recurrence (21). For this reason, unless there is a serious medical contraindication to a more lengthy operation, complete cyst removal should be the surgical goal. The four cases (18%) of incomplete cyst removal highlight the difficulties that may be encountered with an endoscopic approach. Aside from the one intentional subtotal resection described above, resection was limited by adherence of the cyst wall to the body of the fornix in two cases and to the walls of the third ventricle in one case. The residuals in the latter three cases were small and radiographically occult. When comparing results across series, it is worth noting that other authors have classified such cases as complete resections and that cyst adherence to critical structures also presents a challenge in open approaches (13, 29). This study is limited by its retrospective design. Although the follow-up is short, the length of follow-up is comparable to other reports. Longer-term follow-up over a 5- to 10-year period will be necessary to accurately assess recurrence rates. Although the number of patients is small, it is similar to those reported in prior endoscopic series. It is not possible to validate the value of our anterolateral approach using the data we provide; no control group is available of those who had similar surgery from a more traditional trajectory and entry point. Additionally, since no attempt was made to treat some patients with a single instrument technique, there is no comparison group in this regard. Realistically, such a trial is not possible. Nonetheless, we believe we provide a sound rationale for the value of an anterolateral, dual-
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instrument endoscopic approach that is supported by favorable outcomes compared to reported historical data and our own previously published results (16). CONCLUSIONS An anterolateral approach for endoscopic resection of colloid cysts using a dualinstrument technique provides favorable results with respect to completeness of cyst removal, and a similar morbidity rate, when compared to historically reported results. Our improved results compared to our prior experience reflect the learning curve associated with endoscopic techniques. In addition, our review of the literature demonstrates the need for a standardized scale to grade completeness of colloid cyst resection. REFERENCES 1. Abdou MS, Cohen AR: Endoscopic treatment of colloid cysts of the third ventricle: Technical note and review of the literature. J Neurosurg 89: 1062-1068, 1998. 2. Antunes JL, Louis KM, Ganti SR: Colloid cysts of the third ventricle. Neurosurgery 7:450-455, 1980. 3. Batnitzky S, Sarwar M, Leeds NE, Schechter MM, zar-Kia B: Colloid cysts of the third ventricle. Radiology 112:327-341, 1974. 4. Boogaarts HD, Decq P, Grotenhuis JA, Le GC, Nseir R, Jarraya B, Djindjian M, Beems T: Longterm results of the neuroendoscopic management of colloid cysts of the third ventricle: a series of 90 cases. Neurosurgery 68:179-187, 2011. 5. 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. 6. Decq P, Le GC, Brugieres P, Djindjian M, Silva D, Keravel Y, Melon E, Nguyen JP: Endoscopic management of colloid cysts. Neurosurgery 42: 1288-1294, 1998. 7. Deinsberger W, Boker DK, Bothe HW, Samii M: Stereotactic endoscopic treatment of colloid cysts of the third ventricle. Acta Neurochir (Wien) 131: 260-264, 1994. 8. Deinsberger W, Boker DK, Samii M: Flexible endoscopes in treatment of colloid cysts of the third ventricle. Minim Invasive Neurosurg 37: 12-16, 1994. 9. Desai KI, Nadkarni TD, Muzumdar DP, Goel AH: Surgical management of colloid cyst of the third ventricle a study of 105 cases. Surg Neurol 57: 295-302, 2002. 10. Engh JA, Lunsford LD, Amin DV, Ochalski PG, Fernandez-Miranda J, Prevedello DM, Kassam AB:
Stereotactically guided endoscopic port surgery for intraventricular tumor and colloid cyst resection. Neurosurgery 67:ons198-ons204, 2010. 11. Gokalp HZ, Yuceer N, Arasil E, Erdogan A, Dincer C, Baskaya M: Colloid cyst of the third ventricle: Evaluation of 28 cases of colloid cyst of the third ventricle operated on by transcortical transventricular (25 cases) and transcallosal/ transventricular (3 cases) approaches. Acta Neurochir (Wien) 138:45-49, 1996. 12. Greenlee JD, Teo C, Ghahreman A, Kwok B: Purely endoscopic resection of colloid cysts. Neurosurgery 62:51-55, 2008. 13. Grondin RT, Hader W, MacRae ME, Hamilton MG: Endoscopic versus microsurgical resection of third ventricle colloid cysts. Can J Neurol Sci 34:197-207, 2007. 14. Hellwig D, Bauer BL, Schulte M, Gatscher S, Riegel T, Bertalanffy H: Neuroendoscopic treatment for colloid cysts of the third ventricle: the experience of a decade. Neurosurgery 52:525-533, 2003. 15. 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. 16. Horn EM, Feiz-Erfan I, Bristol RE, Lekovic GP, Goslar PW, Smith KA, Nakaji P, Spetzler RF: Treatment options for third ventricular colloid cysts: comparison of open microsurgical versus endoscopic resection. Neurosurgery 60:613-618, 2007. 17. Kehler U, Brunori A, Gliemroth J, Nowak G, Delitala A, Chiappetta F, Arnold H: Twenty colloid cysts comparison of endoscopic and microsurgical management. Minim Invasive Neurosurg 44: 121-127, 2001. 18. Lewis AI, Crone KR, Taha J, van Loveren HR, Yeh HS, Tew JM Jr: Surgical resection of third ventricle colloid cysts: Preliminary results comparing transcallosal microsurgery with endoscopy. J Neurosurg 81:174-178, 1994. 19. Little JR, MacCarty CS: Colloid cysts of the third ventricle. J Neurosurg 40:230-235, 1974. 20. Mathiesen T, Grane P, Lindgren L, Lindquist C: Third ventricle colloid cysts: a consecutive 12-year series. J Neurosurg 86:5-12, 1997. 21. 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. 22. Mishra S, Chandra PS, Suri A, Rajender K, Sharma BS, Mahapatra AK: Endoscopic management of third ventricular colloid cysts: eight years’ institutional experience and description of a new technique. Neurol India 58:412-417, 2010. 23. Nitta M, Symon L: Colloid cysts of the third ventricle: A review of 36 cases. Acta Neurochir (Wien) 76:99-104, 1985.
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24. Pollock BE, Huston J III: Natural history of asymptomatic colloid cysts of the third ventricle. J Neurosurg 91:364-369, 1999. 25. Pollock BE, Schreiner SA, Huston J III: A theory on the natural history of colloid cysts of the third ventricle. Neurosurgery 46:1077-1081, 2000. 26. Powell MP, Torrens MJ, Thomson JL, Horgan JG: Isodense colloid cysts of the third ventricle: a diagnostic and therapeutic problem resolved by ventriculoscopy. Neurosurgery 13:234-237, 1983. 27. Rodziewicz GS, Smith MV, Hodge CJ Jr: Endoscopic colloid cyst surgery. Neurosurgery 46: 655-660, 2000. 28. Sampath R, Vannemreddy P, Nanda A: Microsurgical excision of colloid cyst with favorable cognitive outcomes and short operative time and hospital stay: operative techniques and analyses of outcomes with review of previous studies. Neurosurgery 66:368-374, 2010.
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29. Shapiro S, Rodgers R, Shah M, Fulkerson D, Campbell RL: Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle. J Neurosurg 110:112-115, 2009. 30. Shucart WA, Stein BM: Transcallosal approach to the anterior ventricular system. Neurosurgery 3: 339-343, 1978. 31. Souweidane MM, Luther N: Endoscopic resection of solid intraventricular brain tumors. J Neurosurg 105:271-278, 2006. 32. Stachura K, Libionka W, Moskala M, Krupa M, Polak J: Colloid cysts of the third ventricle: Endoscopic and open microsurgical management. Neurol Neurochir Pol 43:251-257, 2009.
ventricle: an analysis of 78 cases. Neurol India 59: 542-547, 2011. 34. Teo C: Complete endoscopic removal of colloid cysts: issues of safety and efficacy. Neurosurg Focus 6:e9, 1999.
Conflict of interest statement: Dr. Peter Nakaji serves on the Medtronic Navigation scientific advisory board. The remaining authors have neither conflicts of interest nor financial interests to disclose. Received 20 December 2011; accepted 25 July 2012; published online 28 July 2012 Citation: World Neurosurg. (2013) 80, 5:576-583. http://dx.doi.org/10.1016/j.wneu.2012.07.014 Journal homepage: www.WORLDNEUROSURGERY.org
33. Symss NP, Ramamurthi R, Rao SM, Vasudevan MC, Jain PK, Pande A: Management outcome of the transcallosal, transforaminal approach to colloid cysts of the anterior third
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Endoscopic Endonasal Transmaxillary Approach and Endoscopic Sublabial Transmaxillary Approach: Surgical Decision-Making and Implications of the Nasolacrimal Duct Andrew S. Little1, Peter Nakaji1, John Milligan2
Key words Caldwell-Luc - Endoscope - Skull Base Tumors - Transmaxillary Approach -
Abbreviations and Acronyms SEND: Septal nasolacrimal duct line From 1Barrow Neurological Institute, Division of Neurological Surgery, St Joseph's Hospital and Medical Center, Phoenix, Arizona; and 2Arizona Otolaryngology Consultants, Phoenix, Arizona, USA To whom correspondence should be addressed: Andrew S. Little, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2013) 80, 5:583-590. http://dx.doi.org/10.1016/j.wneu.2012.01.059 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2013 Elsevier Inc. All rights reserved.
INTRODUCTION The pterygopalatine and infratemporal fossae are relatively uncommon sites of skull base pathology such as chordomas, infection, juvenile angiofibromas, and schwannomas. These lesions can be technically challenging to reach because of their deep location and proximity to critical neurovascular structures. There has been a trend
- BACKGROUND:
The nasolacrimal duct resides in the wall of the medial nasal cavity and influences minimal access endoscopic transmaxillary approaches to the lateral skull base. We describe an algorithm for surgical approach selection on the basis of the relationship of the target lesion to a line drawn from the anterior nasal SEptum through the Nasolacrimal Duct to the lesion (i.e., SEND line).
- METHODS:
We use the SEND line to estimate the lateral extent in the endonasal middle meatal transmaxillary approach, where the surgeon has good surgical freedom without the use of angled instruments and endoscopes. Lesions with an epicenter lateral to the SEND line were addressed through a sublabial anterior antrostomy transmaxillary corridor. Tumors with a more medially located epicenter, such as those involving the lateral sphenoid sinus and pterygoid plates, were addressed through the endonasal middle meatal corridor. Extensive tumors involving both domains were addressed through a combination approach.
- RESULTS:
We describe three instructive cases in which the approach selection was determined in part by preoperative assessment of the location of the tumor relative to the SEND line.
- CONCLUSIONS:
The endoscopic sublabial transmaxillary and endoscopic endonasal middle meatal transmaxillary approaches are complementary corridors to the anterior skull base that can be used independently or in combination. The location of the target lesion relative to the SEND line as determined on preoperative imaging can serve as a guide for surgical decision making.
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