Limitations of the transcallosal transchoroidal approach to the third ventricle

Endoscopic approaches to the posterior wall of the third ventricle: An anatomical comparison

INTRODUCTION

Surgery of lesions in the posterior wall of the third ventricle requires great expertise due to its deep location and important surrounding structures. This region has been traditionally reached through a supracerebellar infratentorial approach, but new options have emerged, especially with the development of neuroendoscopy.

METHODS

One formalin-fixed cadaver human head was dissected. Five different endoscopic approaches were performed: interhemispheric transcallosal transchoroidal, frontal transforaminal transchoroidal, supraorbital subfrontal translamina terminalis, expanded endonasal, and supracerebellar infratentorial. An anatomical description of the different approaches was conducted and quantitative measurements (craniocaudal and latero-lateral distances) were taken using the StealthStation ® workstation after performing a CT scan of the specimen.

RESULTS

The interhemispheric transcallosal transchoroidal, frontal transforaminal transchoroidal, and supraorbital subfrontal translamina terminalis approaches provided great view of all the structures of the posterior wall of the third ventricle. Maximum craniocaudal distance was obtained through the supraorbital subfrontal translamina terminalis approach (10.6 mm), with great difference from the expanded endonasal approach (5.2 mm). The widest latero-lateral distance from inside the third ventricle was achieved through the interhemispheric transcallosal transchoroidal approach (4.6 mm), similar to the expanded endonasal (4.1 mm), and differing from the supraorbital subfrontal translamina terminalis (2.4 mm).

CONCLUSIONS

The endoscopic approaches provided an adequate alternative to more traditional microsurgical approaches to the posterior wall of the third ventricle, with a great view of all its structures. The selection of the approach must be taken under consideration in each case.

Quantitative analysis of exposure and surgical maneuverability of three purely endoscopic keyhole approaches to the floor of the third ventricle

BACKGROUND

The quantitative anatomic analysis of comprehensively endoscopic approaches to the third ventricle is scarce at present. The objective of the study is to quantitatively assess and compare the exposure and microsurgical maneuverability of three absolutely endoscopic keyhole approaches, including interhemispheric transcallosal transchoroidal (TCTC), frontal transforminal transchoroidal (TFTC) and supraorbital subfrontal translamina terminalis (SFTL) approaches.

METHODS

Anatomical dissections and exposure of the important structures of the third ventricle were performed using six formalin-fixed cadaveric human heads (twelve sides) under endoscope. Tubular retractor system was used in the TFTC approach. Quantitative anatomical relationship between the important landmarks were obtained. Moreover, the exposure and surgical operability of three approaches were evaluated through applying the rating scale and accomplishing the quantitative anatomic analysis, area of surgical freedom and angle of attack.

RESULTS

The mediolateral, anteroposterior (AM: between aqueduct and mammillary body; IM: between infundibular recess and mammillary body) and superoinferior distance of TCTC, TFTC and SFTL approaches were 4.0±1.0, 4.2±0.4, 4.1±1.1 mm; 17.3±1.4, 17.6±0.5, 12.8±3.3 mm (AM); 7.7±0.3, 7.8±0.5 mm, not measured (IM); and 5.6±0.3, 7.8±0.8, 7.8±1.5 mm, respectively. Similar to TFTC, the exposed landmarks of TCTC were almost scored a "4" by three neurosurgeons except the infundibular recess scored a "3" according to the rating scale. During the SFTL approach, apart from the roof, the majority of the landmarks were scored a "4" except for the infundibular recess, which was scored a "3." The mean area of surgical freedom of TCTC (0° endoscope: 220±47; 30°: 247±56 mm2) was not significantly different from that of TFTC approach (0° endoscope: 216±49; 30°: 245±53 mm2) under same endoscope, P>0.05. Mean angle of attack of TCTC (0° endoscope: 21±4°; 30°: 26±4°) was significantly larger than that of TFTC approach (0° endoscope: 16±3°; 30°: 19±3°), P<0.05.

CONCLUSIONS

Purely endoscopic TCTC and TFTC approaches offer brilliant exposure of the anterior, middle and posterior third ventricle. TCTC approach may have better surgical maneuverability than TFTC approach. Despite the long working distance, the whole third ventricle are exposed well except for the roof in the SFTL approach, and surgical manipulation can be accomplished smoothly.

Endoscope-assisted microsurgical resection of a third ventricular immature teratoma

BACKGROUND

Reaching a tumor within the third ventricle is challenging, and planning an accessible trajectory is crucial without injuring the surrounding structures. We report a 5-year-old boy presented with headache and a seizure where sequential MRI brain studies in a short time period revealed a rapid growing immature teratoma within the third ventricle with hydrocephalic changes. Several management procedures were performed for CSF diversion and medical treatment of the tumor with chemotherapy and stem cell therapy. The tumor was rapidly growing, and surgical excision was decided. Total resection was achieved via endoscope-assisted microsurgical transcallosal approach. Seven years after surgery, the patient experienced no recurrence of the tumor with a favorable clinical condition.

CONCLUSION

We report a rare case of posterior third ventricular immature teratoma where the endoscope-assisted microsurgical technique was implemented with favorable long-term postoperative outcome.

Surgical Approaches to the Third Ventricle: An Update

The third ventricle is located in the deepest part of the brain and is delimited by both telencephalic and diencephalic structures. Its location makes every surgical procedure inside or around it quite challenging, due to the distance from the surface to the fragility of the neurovascular structures that is necessary to dissect before entering its cavity and to the narrow surgical corridors through which it is necessary to work. Its geometric localization inside the cranial cavity and the anatomical relationship with the interhemispheric fissure offers nevertheless to the surgeon an impressive variety of surgical approaches, which allow to reach every millimeter of the third ventricle lumen. Mastering properly all these approaches requires an impressive anatomical knowledge, the best available technology, and most refined technical skills, making the surgery of the third ventricle a point of excellence in the evolution of each neurosurgeon. The development of neuronavigation and neuroendoscopy has been a revolution in neurosurgery in the last 20 years and offered special advantages for the surgery of the third ventricle. In fact, the narrow corridors of approach make the precision of the neuronavigation and the enlightenment and magnification of the neuroendoscopy especially useful to reach the third ventricle cavity and working inside or around it. This chapter reviews the history of the surgery of the third ventricle and offers an update of the variety of surgical corridors identified and of the technology now available to properly work through them and inside the third ventricle cavity.

Endoscopic Endonasal Approach to the Third Ventricle Using the Surgical Corridor of the Reverse Third Ventriculostomy: Anatomo-Surgical Nuances

Objective Surgical access to the third ventricle can be achieved through various corridors depending on the location and extent of the lesion; however, traditional transcranial approaches risk damage to multiple critical neural structures.

Methods Endonasal approach similar to corridor of the reverse third ventriculostomy (ERTV) was surgically simulated in eight cadaveric heads. Fiber dissections were additionally performed within the third ventricle along the endoscopic route. Additionally, we present a case of ERTV in a patient with craniopharyngioma extending into the third ventricle.

Results The ERTV allowed adequate intraventricular visualization along the third ventricle. The extracranial step of the surgical corridor included a bony window in the sellar floor, tuberculum sella, and the lower part of the planum sphenoidale. ERTV provided an intraventricular surgical field along the foramen of Monro to expose an area bordered by the fornix anteriorly, thalamus laterally, anterior commissure anterior superiorly, posterior commissure, habenula and pineal gland posteriorly, and aqueduct of Sylvius centered posterior inferiorly.

Conclusion The third ventricle can safely be accessed through ERTV either above or below the pituitary gland. ERTV provides a wide exposure of the third ventricle through the tuber cinereum and offers access to the anterior part as far as the anterior commissure and precommissural part of fornix and the whole length of the posterior part. Endoscopic ERTV may be a suitable alternative to transcranial approaches to access the third ventricle in selected patients.

Endoscopic Endonasal Approach to the Third Ventricle using the Corridor of the Reverse Third Ventriculostomy: anatomo-surgical nuances

Objective: Surgical access to the third ventricle can be achieved through various corridors depending on the location and extent of the lesion; however, traditional transcranial approaches risk damage to multiple critical neural structures. Methods: Endonasal approach similar to corridor of the reverse third ventriculostomy (ERTV) was surgically simulated in eight cadaveric heads. Fiber dissections were additionally performed within the third ventricle along the endoscopic route. Additionally, we present a case of ERTV in a patient with craniopharyngioma extending into the third ventricle. Results: The ERTV allowed adequate intraventricular visualization along the third ventricle. The extracranial step of the surgical corridor included a bony window in the sellar floor, tuberculum sella and the lower part of the planum sphenoidale. ERTV provided an intraventricular surgical field along the foramen of Monro to expose an area bordered by the fornix anteriorly, thalamus laterally, anterior commissure anterior superiorly, posterior commissure, habenula and pineal gland posteriorly, and aqueduct of Sylvius centered posterior inferiorly. Conclusion: The third ventricle can safely be accessed through ERTV either above or below the pituitary gland. ERTV provides a wide exposure of the third ventricle through the tuber cinereum and offers access to the anterior part as far as the anterior commissure and pre-commissural part of fornix and the whole length of the posterior part. Endoscopic ERTV may be a suitable alternative to transcranial approaches to access the third ventricle in selected patients.

The transcallosal transchoroidal approach to the diencephalic-mesencephalic junction: how I do it

BACKGROUND

Different approaches have to be considered for lesions of the diencephalic-mesencephalic junction based on the localization, extension of the lesion, and relationship to the ventricular system.

METHOD

We present the case of a young lady who presented with a cavernoma of the junction of midbrain and diencephalon after an episode of hemorrhage. The microsurgical anatomy of the trans-callosal trans-choroidal approach for this lesion is described along with its advantages and limitations.

CONCLUSION

The trans-choroidal approach allows adequate access to lesions of the diencephalic-mesencephalic junction that project into the third ventricle.

Cavernous Malformations in and Around the Third Ventricle: Indications, Approaches, and Outcomes

BACKGROUND

Cavernous malformations in structures in and around the third ventricle are a challenging conceptual and surgical problem. No consensus exists on the ideal approach to such lesions.

OBJECTIVE

To perform a retrospective review of our institutional database to identify and evaluate approaches used to treat cavernous malformations located in and around the third ventricle.

METHODS

Information was extracted regarding lesion size and location, extent of resection, time to last follow-up, surgical approach, presenting symptoms, preoperative and postoperative neurological status, and specific approach-related morbidity.

RESULTS

All 39 neurosurgical operations (in 36 patients) were either an anterior interhemispheric (AIH) (44%, 17/39) or a supracerebellar infratentorial (SCIT) (56%, 22/39) approach. Gross-total resection was achieved in 23 of 39 procedures (59%), a near-total resection in 1 (3%), and subtotal resection in 15 (38%). For the 31 patients with at least 3 mo of follow-up, the mean modified Rankin Scale (mRS) score was 1.5. Of the 31 patients, 25 (81%) had an mRS score of 0 to 2, 4 had a mRS score of 3 (13%), and 1 each had a mRS score of 4 (3%) or 5 (3%).

CONCLUSION

Most approaches to cavernous malformations in and around the third ventricle treated at our institution have been either an AIH or a SCIT approach. The AIH approach was used for lesions involving the lateral wall of the third ventricle or the midline third ventricular floor, whereas the SCIT approach was used for lesions extending from the third ventricle into the dorsolateral midbrain, with acceptable clinical results.

Thalamomesencephalic cavernoma: anterior transcallosal transchoroidal approach

We present a case of a 62-year-old man with acute onset of diplopia, headache, and vomiting for a bleeding thalamomesencephalic cavernoma. The lesion was removed via the anterior transcallosal transchoroidal approach. His head was slightly flexed and a right paramedian craniotomy for an interhemispheric approach was performed. The interhemispheric fissure was split and, after callosotomy, the choroidal fissure was opened along the tenia fornicis to enter the velum interpositum and enlarge the foramen of Monro. The cavernoma was then identified and resected. There were no long-term postoperative neurological deficits. This approach is a valid alternative for thalamomesencephalic lesions.

The video can be found here: https://youtu.be/DJdorbzDnH0.

Resection of tumors of the third ventricle involving the hypothalamus: effects on body mass index using a dedicated surgical approach

Resection of large lesions growing into the third ventricle is considered nowadays still a demanding surgery, due to the high risk of severe endocrine and neurological complications. Some neurosurgical approaches were considered in the past the procedures of choice to access the third ventricle, however they were burden by endocrine and neurological consequences, like memory loss and epilepsy. We report here the endocrine and functional results in a series of patients operated with a recently developed approach specifically tailored for the resection of large lesions growing into the third ventricle. Authors conducted a retrospective analysis on 10 patients, operated between 2011 and 2012, for the resection of large tumors growing into the third ventricle. Total resection was achieved in all patients. No perioperative deaths were recorded and all patients were alive after the follow-up. One year after surgery 8/10 patients had an excellent outcome with a Karnofsky Performance Status of 100 and a Glasgow Outcome score of 5, with 8 patients experiencing an improvement of the Body Mass Index. Modern neurosurgery allows a safe and effective treatment of large lesions growing into the third ventricle with a postoperative good functional status.

Comparative anatomical analysis of the transcallosal-transchoroidal and transcallosal-transforniceal-transchoroidal approaches to the third ventricle

OBJECTIVE

Access to the third ventricle is a veritable challenge to neurosurgeons. In this context, anatomical and morphometric studies are useful for establishing the limitations and advantages of a particular surgical approach. The transchoroidal approach is versatile and provides adequate exposure of the middle and posterior regions of the third ventricle. However, the fornix column limits the exposure of the anterior region of the third ventricle. There is evidence that the unilateral section of the fornix column has little effect on cognitive function. This study compared the anatomical exposure afforded by the transforniceal-transchoroidal approach with that of the transchoroidal approach. In addition, a morphometric evaluation of structures that are relevant to and common in the 2 approaches was performed.

METHODS

The anatomical exposure provided by the transcallosal-transchoroidal and transcallosal-transforniceal-transchoroidal approaches was compared in 8 fresh cadavers, using a neuronavigation system. The working area, microsurgical exposure area, and angular exposure on the longitudinal and transversal planes of 2 anatomical targets (tuber cinereum and cerebral aqueduct) were compared. Additionally, the thickness of the right frontal lobe parenchyma, thickness of the corpus callosum trunk, and longitudinal diameter of the interventricular foramen were measured. The values obtained were submitted to statistical analysis using the Wilcoxon test.

RESULTS

In the quantitative evaluation, compared with the transchoroidal approach, the transforniceal-transchoroidal approach provided a greater mean working area (transforniceal-transchoroidal 150 ± 11 mm2; transchoroidal 121 ± 8 mm2; p < 0.05), larger mean microsurgical exposure area (transforniceal-transchoroidal 101 ± 9 mm2; transchoroidal 80 ± 5 mm2; p < 0.05), larger mean angular exposure area on the longitudinal plane for the tuber cinereum (transforniceal-transchoroidal 71° ± 7°; transchoroidal 64° ± 6°; p < 0.05), and larger mean angular exposure area on the longitudinal plane for the cerebral aqueduct (transforniceal-transchoroidal 62° ± 6°; transchoroidal 55° ± 5°; p < 0.05). No differences were observed in angular exposure along the transverse axis for either anatomical target (tuber cinereum and cerebral aqueduct; p > 0.05). The mean thickness of the right frontal lobe parenchyma was 35 ± 3 mm, the mean thickness of the corpus callosum trunk was 10 ± 1 mm, and the mean longitudinal diameter of the interventricular foramen was 4.6 ± 0.4 mm. In the qualitative assessment, it was noted that the transforniceal-transchoroidal approach led to greater exposure of the third ventricle anterior region structures. There was no difference between approaches in the exposure of the structures of the middle and posterior region.

CONCLUSIONS

The transforniceal-transchoroidal approach provides greater surgical exposure of the third ventricle anterior region than that offered by the transchoroidal approach. In the population studied, morphometric analysis established mean values for anatomical structures common to both approaches.

Comparative anatomical analysis of the transcallosal-transchoroidal and transcallosal-transforniceal-transchoroidal approaches to the third ventricle

OBJECTIVE

Access to the third ventricle is a veritable challenge to neurosurgeons. In this context, anatomical and morphometric studies are useful for establishing the limitations and advantages of a particular surgical approach. The transchoroidal approach is versatile and provides adequate exposure of the middle and posterior regions of the third ventricle. However, the fornix column limits the exposure of the anterior region of the third ventricle. There is evidence that the unilateral section of the fornix column has little effect on cognitive function. This study compared the anatomical exposure afforded by the transforniceal-transchoroidal approach with that of the transchoroidal approach. In addition, a morphometric evaluation of structures that are relevant to and common in the 2 approaches was performed.

METHODS

The anatomical exposure provided by the transcallosal-transchoroidal and transcallosal-transforniceal-transchoroidal approaches was compared in 8 fresh cadavers, using a neuronavigation system. The working area, microsurgical exposure area, and angular exposure on the longitudinal and transversal planes of 2 anatomical targets (tuber cinereum and cerebral aqueduct) were compared. Additionally, the thickness of the right frontal lobe parenchyma, thickness of the corpus callosum trunk, and longitudinal diameter of the interventricular foramen were measured. The values obtained were submitted to statistical analysis using the Wilcoxon test.

RESULTS

In the quantitative evaluation, compared with the transchoroidal approach, the transforniceal-transchoroidal approach provided a greater mean working area (transforniceal-transchoroidal 150 ± 11 mm2; transchoroidal 121 ± 8 mm2; p < 0.05), larger mean microsurgical exposure area (transforniceal-transchoroidal 101 ± 9 mm2; transchoroidal 80 ± 5 mm2; p < 0.05), larger mean angular exposure area on the longitudinal plane for the tuber cinereum (transforniceal-transchoroidal 71° ± 7°; transchoroidal 64° ± 6°; p < 0.05), and larger mean angular exposure area on the longitudinal plane for the cerebral aqueduct (transforniceal-transchoroidal 62° ± 6°; transchoroidal 55° ± 5°; p < 0.05). No differences were observed in angular exposure along the transverse axis for either anatomical target (tuber cinereum and cerebral aqueduct; p > 0.05). The mean thickness of the right frontal lobe parenchyma was 35 ± 3 mm, the mean thickness of the corpus callosum trunk was 10 ± 1 mm, and the mean longitudinal diameter of the interventricular foramen was 4.6 ± 0.4 mm. In the qualitative assessment, it was noted that the transforniceal-transchoroidal approach led to greater exposure of the third ventricle anterior region structures. There was no difference between approaches in the exposure of the structures of the middle and posterior region.

CONCLUSIONS

The transforniceal-transchoroidal approach provides greater surgical exposure of the third ventricle anterior region than that offered by the transchoroidal approach. In the population studied, morphometric analysis established mean values for anatomical structures common to both approaches.

Extended Endoscopic Endonasal Approach to the Third Ventricle: Multimodal Anatomical Study with Surgical Implications

INTRODUCTION

A certain interest for the extended endoscopic endonasal approach for the management of sellar-suprasellar lesions extending inside the third ventricle has been growing in recent years. The aim of this anatomical study was to evaluate the possibilities in terms of exposure and access to the different areas of the third ventricle, with the endoscopic endonasal technique, as compared with the microscopic or endoscopic view provided via different transcranial approaches. The advantages and limitations of both surgical pathways were analyzed.

MATERIALS AND METHODS

Ten human cadaver heads were dissected. In order to standardize the comparison between the endonasal and the transcranial routes, the third ventricle cavity has been divided into four areas by means of two ideal planes, one passing through the optic chiasm and the interthalamic commissure and one passing through the posterior edge of the foramen of Monro and the interthalamic commissure. Accordingly, two anterior (infundibular and foraminal) and two posterior (mesencephalic and tectal) areas have been defined.

RESULTS

The endoscopic endonasal approach allows for exploration and surgical maneuverability, especially in the anterior areas of the third ventricle. In the infundibular and foraminal areas the surgical maneuverability seems to be better as compared with that obtained inside the mesencephalic region, while via the endonasal route the tectal area could not be reached. In particular, the infundibular area can be explored either passing through the lamina terminalis or via the tuber cinereum; this latter trajectory enables visualization of the foramina of Monro and the floor of the third ventricle up to the pineal recess.

CONCLUSION

This anatomical study shows that the lamina terminalis and, above all, the tuber cinereum represent two safe entry points defining possible surgical corridors to be considered for the extended endoscopic endonasal approach to the third ventricle.

A flexible endoscope-assisted interhemispheric transcallosal approach through the contralateral ventricle for the removal of a third ventricle craniopharyngioma: A technical report

Background:

Intraventricular craniopharyngiomas are difficult to remove. We combined an interhemispheric transcallosal approach with a flexible endoscope (videoscope) for successful tumor removal.

Case Description:

A 52-year-old male complained of general fatigue and memory disturbance. Magnetic resonance imaging revealed a well-enhanced third ventricle mass with dilatation of lateral ventricles. During removal with the interhemispheric transcallosal approach, a videoscope that was inserted into the left lateral ventricle revealed the interface of the tumor and the ventricular wall. The tumor was pushed to the right using forceps and removed totally through the right foramen of Monro without any fornix injury.

Conclusion:

This procedure is a safe option for removing third ventricular tumors especially in the case with hydrocephalus.

The Transcallosal Anterior Interfoniceal Approach: A Microsurgical Anatomy Study

Objectives A plethora of surgical strategies have been described to reach deep-seated lesions situated within the third ventricle including the Rosenfeld, or transcallosal anterior interfoniceal (TAIF), approach. First introduced in 2001, it consists of a small callosotomy followed by the midline transseptal dissection of fornices to enter the roof of the third ventricle. The aim of this microsurgical anatomy study is to describe and show each stage of the surgical procedure, focusing on the possible trajectories to anatomical landmarks. Participants A total of 20 adult cadaveric specimens were used in this study. Using ×3 to ×40 magnifications, the surgical dissection was performed in a stepwise fashion, and the transcallosal anterior interforniceal approach was performed, analyzed, and described. Results In 5 specimens of 10, a cavum septum pellucidum was depicted. In 5 cases of 20 after the callosotomy ,the lateral ventricular cavities were reached. Different orientation of the microscope allowed us to define three surgical trajectories to visualize the region of interest without exposing important functional areas. Conclusion The TAIF represents a minimally invasive approach to the third ventricle; its tricky surgical steps make appropriate anatomical dissection training essential to become confident and skilled in performing this approach.

A 34-year-old woman with brainstem cavernous malformation: the anterior transcallosal transchoroidal approach and literature review

Mesencephalic cavernous malformations (MeCMs) account for 4 to 35% of the cavernous malformations of the central nervous system and are generally rare. Surgical resection of brainstem cavernomas are high-risk procedures and can be challenging to the neurosurgeon. Several approaches have been described, but the approach must allow for a straight line of sight in which the surgeon, the pial incision, and the MeCM are all collinear. This alignment provides the best view of the lesion while minimizing the need for brainstem retraction. The pial incision should be chosen to minimize the distance to the lesion while avoiding critical nuclei and tracts. In this case report, we present a 34-year-old woman with a MeCM resected by an anterior transcallosal transchoroidal approach with minimal damage to surrounding brain tissue. Although rarely used, it should be considered a valuable alternative to ventrally located brainstem cavernomas.

Technical strategies for the transcallosal transforaminal approach to third ventricle tumors: expanding the operative corridor

OBJECT

There are a number of surgical approaches to the third ventricle, each with advantages and disadvantages. Which approach to use depends on the location of the lesion within the ventricle, the goals of the operation, and the surgeon's experience. The authors present their results in children with a modified approach through the expanded foramen of Monro.

METHODS

A retrospective study was conducted to identify and analyze all children who underwent what the authors term the "expanded transforaminal" approach to the third ventricle between 2010 and 2013. Perioperative data included patient demographics, signs and symptoms on presentation, tumor characteristics (type, origin, and size), complications, and clinical and radiographic outcome at final follow-up.

RESULTS

Twelve patients were identified (5 female, 7 male) with a mean age of 9 years (range 2-19 years). Two patients underwent gross-total resections, whereas 10 resections were less than total. There were no instances of venous infarction, significant intraoperative bleeding, or short-term memory deficits. Of the 12 patients, 7 suffered a total of 17 complications. Disruption of neuroendocrine function occurred in 4 patients: 2 with transient diabetes insipidus, 2 with permanent panhypopituitarism, and 1 with central hypothroidism (1 patient had 2 complications). The most common group of complications were CSF-related, including 2 patients requiring a new shunt. There was 1 approach-related injury to the fornix, which did not result in any clinical deficits. One child with an aggressive malignancy died of tumor progression 6 months after surgery. Of the remaining 11 patients, none have experienced tumor recurrence or progression to date.

CONCLUSIONS

The expanded transcallosal transforaminal approach is a safe and relatively easy method of exploiting a natural pathway to the third ventricle, but there remain blind zones in the anterosuperior and posterosuperior regions of the third ventricle.

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

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

Transcallosal approach to third ventricle tumors: how I do it

BACKGROUND

The transcallosal approach provides a direct corridor to the lesions lying in the third ventricle with distinct advantages over alternative routes, such as the possibility to use multiple corridors for tumor resection.

METHOD

Here we present a personal perspective of the surgery of tumors of the anterior portion of the third ventricle using this approach.

CONCLUSIONS

This approach requires the ability to move around many neurovascular, cortical, and white matter structures. Knowledge of regional anatomy and adherence to principles of microsurgery are basic requirements to obtain a favorable outcome.