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ARTICLE IN PRESS Neurochirurgie xxx (2015) xxx–xxx
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ScienceDirect www.sciencedirect.com
Report 2013: Tumors of the pineal region
Interest and limits of endoscopic approaches for pineal region tumours Approche endoscopique des tumeurs de la région pinéale : intérêts et limites D. Chaussemy , H. Cebulla , A. Coca , S. Chibarro , F. Proust ∗ , P. Kehrli Department of neurosurgery, Strasbourg university hospital, hôpital Hautepierre, avenue Molière, 67000 Strasbourg cedex, France
a r t i c l e
i n f o
Article history: Received 10 February 2015 Received in revised form 7 March 2015 Accepted 16 March 2015 Available online xxx Keywords: Pineal region Instrumentation Endoscopy Exoscope
a b s t r a c t Endoscopy of pineal region tumours has been developed since the year 2000 either via a transventricular or extracerebral approach. The initial purpose of applying neuroendoscopy in the management of pineal region tumours was to resolve the obstructive hydrocephalus, and identify the pathological characteristics of the tumour. Based on this approach, a piecemeal resection of the tumour can be performed. The approaches, derived from the microsurgical pathway using an endoscope to expose the operative field, have been proposed either via an infratentorial supracerebellar approach or posterior transtentorial interhemispheric approach. Neuroendoscopic procedures can be considered as a therapeutic alternative to the microsurgical approach when CSF markers are negative. This procedure is considered mini-invasive for the approach along the surgical corridor access but extensive and in depth at the interface between the tumour and the surrounding neurological parenchyma. The limitations and complications are related to the type of procedure (mono- or bimanual) as well as the tumoral characteristics. Different approaches are presented in detail in order to avoid the occurrence of any surgical complications. © 2015 Elsevier Masson SAS. All rights reserved.
r é s u m é Mots clés : Région pinéale Endoscopie Exoscope Complications
L’endoscopie des tumeurs de la région pinéale est proposée depuis les années 2000, que ce soit par voie transventriculaire ou extracérébrale. Au départ, l’objectif était de résoudre l’hydrocéphalie obstructive par perforation du plancher du 3e ventricule. Utilisant cet accès pour réaliser des biopsies, la possibilité de résection tumorale a été rapidement proposée par cette voie transventriculaire. Les approches extracérébrales, dérivées des voies microchirurgicales supracérébelleuses ou transtentorielles permettent de travailler selon une dissection bimanuelle comparable à celle réalisée sous microscope opératoire. Ces procédures considérées comme mini-invasives le sont uniquement pour l’approche réduisant à son strict minimum les dissections tissulaires mais en profondeur, la largeur du champ opératoire en fait une procédure extensive à haut risque fonctionnel pour les structures environnantes. La difficulté opératoire est liée à la procédure selon l’usage de procédure mono- ou bimanuelle mais aussi aux caractéristiques de la tumeur en termes de vascularisation, de consistance, de taille et de risque de dissémination liquidienne de cellules tumorales. Le futur serait un système hybride entre le microscope opératoire et l’endoscopie. © 2015 Elsevier Masson SAS. Tous droits réservés.
1. Introduction Pineal region tumours are rare, accounting for 0.4% of neoplasms found in the central nervous system [1]. Overall treatment
∗ Corresponding author. E-mail address: [email protected] (F. Proust).
strategies for these tumours vary significantly depending on the histological diagnosis and the midbrain compression responsible for obstructive hydrocephalus. Except for patients where elevated serum or CSF markers levels are diagnostic, histopathological identification is the answer to the management involving surgical resection or biopsy, radiation therapy and chemotherapy. The biopsy may be performed via open surgery, stereotactic or an endoscopic approach.
http://dx.doi.org/10.1016/j.neuchi.2015.03.001 0028-3770/© 2015 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
G Model NEUCHI-702; No. of Pages 4
ARTICLE IN PRESS D. Chaussemy et al. / Neurochirurgie xxx (2015) xxx–xxx
2
Endoscopy of pineal region tumours has been developed since the year 2000 [2–4] either via transventricular or extracerebral approach sometimes in complement to the microscopic exposure. Based on the literature, we review the different approaches and discuss the indication and limitations. 2. Different endoscopic procedures Neuroendoscopic procedures for brain tumours were initially developed as an approach to intraventricular lesions, in particular third ventricular tumours. However, progressively the endoscopic exposure of brain tumours used the anatomical fissure and the microscopic approaches either isolated or in combination with conventional optical magnification. 2.1. Transventricular technique The initial purpose of applying neuroendoscopy in the management of pineal region tumours was to resolve the obstructive hydrocephalus, and identify the pathological characteristics of the tumour [3]. Thus, the anterior neuroendoscopic approach is suitable not only to obtain tissue samples from multiple parts of the tumours but also to sometimes complete the procedure by a complete debulking of the tumour [5]. Under general anaesthesia, the patient is placed in a supine position with the head secured in a three-pin head holder. The patient’s head is not rotated and kept exactly vertical at 0◦ . The midline, as well as the coronal suture, is identified to create a hole giving access to both the third ventricle floor as well as the most posterior part of the third ventricle. This hole is performed on the pupillary line, 3 cm anterior to the coronal suture [6]. The choice of this burr hole can be determined using neuronavigation in order to obtain an optimal trajectory for both targets. The endoscope is then methodically checked with the scrub nurse (enlightenment, status of the instruments, balloon inflation). After subcutaneous adrenalin infiltration, a vertical skin incision will permit to perform a burr hole, bone cut waxed, dural opening and substantial washing with physiological serum. The endoscope cannula is gently implanted perpendicularly to the cortex toward the frontal horn of the right lateral ventricle. After obtaining cerebrospinal fluid (CSF), a rigid endoscope of 30◦ is introduced and secured into its holder. A CSF sample is then obtained for the dosage of pineal region tumour markers. Under endoscopic view, the anatomical landmarks of the lateral ventricle enabled to push the endoscope through the Monro foramen toward the third ventricle floor. The first step was to perform a ventriculostomy at the floor between the infundibular recesses anteriorly and the mammillary bodies posteriorly. Once the ventriculostomy is done, the endoscope should be gently rotated to the posterior part of the third ventricle in order to identify the anterior pole of the tumour. The neuronavigation could be helpful to confirm the good position of the endoscope tip in front of the tumour. After a careful coagulation of its surface, a biopsy of the tumour is performed using a biopsy rongeur. In case of removal of the tumour, some authors recommended a primary resection under careful haemostasis combining gentle irrigation and coagulation by bipolar coagulation. After, a standard endoscopic third ventriculostomy is completed via a second standard coronal burr hole [5]. 2.2. Extracerebral approaches These approaches are derived from the microsurgical pathway using an endoscope to expose the operative field in complete replacement of the operative microscope and sometimes in combination.
The endoscopic supracerebellar infratentorial approach was initially described to resect a pineal cyst [7], then applied to remove the tumour [8–10]. In the sitting position, the patient is secured to the rigid Mayfield frame. A 3-cm vertical incision followed by a microcraniotomy placed at the inferior margin of the transverse sinus permits a dural opening in a semi-lunar fashion. The gravity-based retraction of the superior surface of cerebellar hemisphere permits to position the endoscope in the infratentorial space via its holder. The endoscope is then advanced along the lower margin of the tentorium. The tentorial bridging veins are respected. On arrival at the deep venous confluence, the endoscope is directed towards the level of pathological entity and the coronally-oriented arachnoid adhesions opened and the dissection started using a bimanual technique. The instruments are independently used and do not pass through the endoscopic ports. Standard microsurgical instruments are used allowing a bimanual dissection under endoscopic view for optical magnification. Then, microdissectors, pituitary forceps, ultrasonic dissector can be conventionally used in order to perform a dissection. The principles of microsurgical resection can be proposed: Telfa cottonoids, gentle dissection, bimanual haemostasis, and use of haemostatic agents. Some authors have reported the use of 3D endoscopic technology (6.5 mm outside diameter, 0◦ and 45◦ endoscopes). The endoscopic approach for this indication has been considered a complement of the optic magnification to verify the complete characteristics of the resection. An interhemispheric transtentorial approach has been reported using the endoscopic procedure [9,11]. This latter mentioned procedure is the one most often proposed in complement to the microsurgical exposition. 3. Indications If the tumour markers AFP and HCG are undetected in serum and ventriculomegaly is found on imaging, neuroendoscopic surgery can be applied at least to resolve the CSF obstruction as well as to obtain a biopsy. The decision between biopsy and tumour removal is based on the tumour intrinsic characteristics such as bleeding, adherence and consistency. Neuroendoscopic procedures can be considered as a therapeutic alternative to the microsurgical approach. 4. Advantages The endoscopic approach is considered a minimally invasive procedure because of the usefulness of the corridor up to the tumoral target, whether it is transgyral or not. These small corridors permit to respect the bridge veins through the pathway, contouring these obstacles to the tumour. The corridors, which condition an accurate view trajectory, require only a small craniotomy and minimal brain retraction. Neuronavigation is a useful tool to optimize the optical view. This procedure decreases the exposure of the functional area as well as the risk of neurological consequences related to the approach. The tip of the endoscope located close to the tumoral process provides an excellent view for intraoperative diagnostic analysis. This type of optical magnification allows resection control behind the venous structures, i.e., internal cerebral veins and optimization of the microdissection. As regards bimanual dissection, under endoscopic control, the overload of the operative field is reduced. Exoscope systems or VITOM-90 are hybrid devices inspired by a combination of quality from the endoscope and operative microscope [12]. The VITOM90 is a rigid rod lens system that looks and functions much like
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
G Model NEUCHI-702; No. of Pages 4
ARTICLE IN PRESS D. Chaussemy et al. / Neurochirurgie xxx (2015) xxx–xxx
a standard endoscope with a long focal distance of 25–30 cm, and therefore is positioned outside the operative cavity. This new technology, as an alternative to the microscopic approach, is attached to a high definition digital camera and displayed on HD video monitor, and has been reported in pineal tumour resection [12]. Moreover, a bimanual manipulation also required conventional instruments which are used for open surgery.
3
can be blood contamination resulting in a perforation risk of the third ventricle floor. This approach exposes patients to difficult pathological reading and false negative results due to the small biopsy size using micro forceps. The rate of non diagnostic or inaccurate diagnosis has been reported to range from 52% to 70% [9]. 6. How to avoid complications?
5. Limitations The limitations of these procedures are classified into those related to the procedure and those related to the tumour. 5.1. Related to the procedure The endoscopic procedure can be performed either in monohand or bimanual manipulation, which exposes different adverse events. In the first case, the long instruments are dedicated for this procedure, and introduced by an intra-endoscopic channel. The consequences of this monohand working were not only the difficulty in dissecting the tumour and achieving haemostasis but also the possibility to transform the endoscopic approach into open surgery. The bimanual dissection was more adaptable to the demands of the interface between the tumour and the surrounding functional area. Nevertheless, the magnified operative field did not allow to control the instrument introduction along the pathway to the target. Furthermore, these successive introductions of instruments during the resection expose functional structures along the surgical corridor to injury. The working with one’s hands, and not within the axis of the viewed trajectory directed on to the screen, required learning curves. In other words, the magnified operative field was projected at distance from the hands. 5.2. Related to the tumors All the difficulty in surgery was related to intraventricular bleeding, the morphological characteristics of the tumour and the dissemination risk related to its pathology. The intraoperative bleeding was directly related to the vascularisation of the tumour. Excessive bleeding subsequently obscured vision making the pursuit of debulking and exposure to occlusion of the ventriculostomy difficult [4]. This bleeding might also occur due to surgical injury of interthalamic adhesion [3]. Some haemorrhagic complications such as intratumoral haemorrhage can complicate the ventriculostomy which is probably due to the sudden decrease of intracranial hypertension (ICH) [13]. Similarly, the ventricular collapse after debulking can be responsible for a subdural haematoma [14]. The morphological characteristics of the tumour such as size and consistency are determining factors for the debulking. Tumour size could also constitute a limiting factor, because it has been considered that this type of procedure was not suitable for tumours larger than 2.5 cm [9,14,15]. Moreover, the excision might be difficult to perform due to its hard consistency. The most suitable presentation is soft tissue which is slightly vascularized and, therefore, more easily aspirated [11]. In this last situation, the tumour size was less elementary for the excision. The CSF dissemination rate of pineal lesions is a risk depending on the tumour type which can reach up to 47% of cases [15]. The rationale would be to keep the subarachnoid space isolated during the biopsy with an abundantly rinsed ventricle [5,15]. The ventriculostomy is performed in a second intention, but the risk
Vigilant preoperative assessment of imaging examinations is required to analyse the difficulties encountered during the resection: distance from the cortex to the frontal horn, position of basilar tip close to the third ventricle floor, anterior protrusion of the tumour into the third ventricle, upward extension of the tumour under the splenium of corpus callosum. The operative checklist must be scrupulously verified: light source, white balance, disposition of instruments, possibility of warm saline irrigation, verification of the permeability of the system in order to avoid any ICH. A surgical assistant must also be present to secure the endoscope holder and manage the irrigation system. Large sheaths are required to use large forceps and a bipolar tip, to obtain a large size biopsy, dissection manoeuvres from the venous system with no tumour traction in order to avoid venous injury. In the bimanual dissection, the endoscope fixed on its holder must permit a wide view of the pathway. For this reason, the exoscope was considered a response to meet this requirement. Intraoperatively, meticulous evaluations are required to select the optimal strategy to perform biopsy alone, or debulking and decide to stop the procedure based on intraoperative conditions. Rules must be careful applied: never use traction, step-by-step haemostasis, gentle dissection and do not hesitate to make the transition to open surgery if conditions become difficult. 7. Conclusion For pineal region tumours, the endoscopic approach constitutes a recent alternative to open microscopic surgery. Considered as mini-invasive procedure because of the thin corridor as a surgical approach, this procedure due to the quality of its exposure resulted in extensive dissection exposing the procedure to neurological consequences. If the monohand manipulation remained a risky gesture, bimanual dissection was a subsequently derived application based on the microsurgical techniques in this process of optical magnification. The future could be an operative field magnification using these devices which are positioned outside the surgical cavity. Financial support None. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. References [1] Pettorini BL, Al-Mahfoud R, Jenkinson MD, Avula S, Pizer B, Mallucci C. Surgical pathway and management of pineal region tumours in children. Childs Nerv Syst 2013;29(3):433–9. [2] Robinson S, Cohen AR. The role of neuroendoscopy in the treatment of pineal region tumors. Surg Neurol 1997;48(4):360–5 [discussion 5–7]. [3] Oi S, Shibata M, Tominaga J, Honda Y, Shinoda M, Takei F, et al. Efficacy of neuroendoscopic procedures in minimally invasive preferential management of pineal region tumors: a prospective study. J Neurosurg 2000;93(2):245–53. [4] Chernov MF, Kamikawa S, Yamane F, Ishihara S, Kubo O, Hori T. Neurofiberscopic biopsy of tumors of the pineal region and posterior third
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
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ARTICLE IN PRESS D. Chaussemy et al. / Neurochirurgie xxx (2015) xxx–xxx
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[5]
[6]
[7]
[8] [9]
ventricle: indications, technique, complications, and results. Neurosurgery 2006;59(2):267–77 [discussion-77]. Chibbaro S, Di Rocco F, Makiese O, Reiss A, Poczos P, Mirone G, et al. Neuroendoscopic management of posterior third ventricle and pineal region tumors: technique, limitation, and possible complication avoidance. Neurosurg Rev 2012;35(3):331–8 [discussion 8–40]. Berhouma M, Ni H, Vallee B. The endoscopic intraventricular management of pineal cysts: a minimally invasive modus operandi. Acta Neurochirurg 2013;155(10):1901–5. Gore PA, Gonzalez LF, Rekate HL, Nakaji P. Endoscopic supracerebellar infratentorial approach for pineal cyst resection: technical case report. Neurosurgery 2008;62(3 Suppl. 1):108–9 [discussion 9]. Sood S, Hoeprich M, Ham SD. Pure endoscopic removal of pineal region tumors. Childs Nerv Syst 2011;27(9):1489–92. Uschold T, Abla AA, Fusco D, Bristol RE, Nakaji P. Supracerebellar infratentorial endoscopically controlled resection of pineal lesions: case series and operative technique. J Neurosurg Pediatr 2011;8(6):554–64.
[10] Zanini MA, Rondinelli G, Fernandes AY. Endoscopic supracerebellar infratentorial parapineal approach for third ventricular colloid cyst in a patient with quadrigeminal cistern arachnoid cyst: Case report. Clin Neurol Neurosurg 2013;115(6):751–5. [11] Broggi M, Darbar A, Teo C. The value of endoscopy in the total resection of pineocytomas. Neurosurgery 2010;67(3 Suppl. Operative):ons159–65. [12] Birch K, Drazin D, Black KL, Williams J, Berci G, Mamelak AN. Clinical experience with a high definition exoscope system for surgery of pineal region lesions. J Clin Neurosci 2014;21(7):1245–9. [13] Al-Tamimi YZ, Bhargava D, Surash S, Ramirez RE, Novegno F, Crimmins DW, et al. Endoscopic biopsy during third ventriculostomy in paediatric pineal region tumours. Childs Nerv Syst 2008;24(11):1323–6. [14] Schroeder HW, Niendorf WR, Gaab MR. Complications of endoscopic third ventriculostomy. J Neurosurg 2002;96(6):1032–40. [15] Sughrue ME. Minimally invasive approaches to the pineal region. Neurosurg Clin N Am 2011;22(3):381–4 [viii].
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
ARTICLE IN PRESS Neurochirurgie xxx (2015) xxx–xxx
Disponible en ligne sur
ScienceDirect www.sciencedirect.com
Report 2013: Tumors of the pineal region
Interest and limits of endoscopic approaches for pineal region tumours Approche endoscopique des tumeurs de la région pinéale : intérêts et limites D. Chaussemy , H. Cebulla , A. Coca , S. Chibarro , F. Proust ∗ , P. Kehrli Department of neurosurgery, Strasbourg university hospital, hôpital Hautepierre, avenue Molière, 67000 Strasbourg cedex, France
a r t i c l e
i n f o
Article history: Received 10 February 2015 Received in revised form 7 March 2015 Accepted 16 March 2015 Available online xxx Keywords: Pineal region Instrumentation Endoscopy Exoscope
a b s t r a c t Endoscopy of pineal region tumours has been developed since the year 2000 either via a transventricular or extracerebral approach. The initial purpose of applying neuroendoscopy in the management of pineal region tumours was to resolve the obstructive hydrocephalus, and identify the pathological characteristics of the tumour. Based on this approach, a piecemeal resection of the tumour can be performed. The approaches, derived from the microsurgical pathway using an endoscope to expose the operative field, have been proposed either via an infratentorial supracerebellar approach or posterior transtentorial interhemispheric approach. Neuroendoscopic procedures can be considered as a therapeutic alternative to the microsurgical approach when CSF markers are negative. This procedure is considered mini-invasive for the approach along the surgical corridor access but extensive and in depth at the interface between the tumour and the surrounding neurological parenchyma. The limitations and complications are related to the type of procedure (mono- or bimanual) as well as the tumoral characteristics. Different approaches are presented in detail in order to avoid the occurrence of any surgical complications. © 2015 Elsevier Masson SAS. All rights reserved.
r é s u m é Mots clés : Région pinéale Endoscopie Exoscope Complications
L’endoscopie des tumeurs de la région pinéale est proposée depuis les années 2000, que ce soit par voie transventriculaire ou extracérébrale. Au départ, l’objectif était de résoudre l’hydrocéphalie obstructive par perforation du plancher du 3e ventricule. Utilisant cet accès pour réaliser des biopsies, la possibilité de résection tumorale a été rapidement proposée par cette voie transventriculaire. Les approches extracérébrales, dérivées des voies microchirurgicales supracérébelleuses ou transtentorielles permettent de travailler selon une dissection bimanuelle comparable à celle réalisée sous microscope opératoire. Ces procédures considérées comme mini-invasives le sont uniquement pour l’approche réduisant à son strict minimum les dissections tissulaires mais en profondeur, la largeur du champ opératoire en fait une procédure extensive à haut risque fonctionnel pour les structures environnantes. La difficulté opératoire est liée à la procédure selon l’usage de procédure mono- ou bimanuelle mais aussi aux caractéristiques de la tumeur en termes de vascularisation, de consistance, de taille et de risque de dissémination liquidienne de cellules tumorales. Le futur serait un système hybride entre le microscope opératoire et l’endoscopie. © 2015 Elsevier Masson SAS. Tous droits réservés.
1. Introduction Pineal region tumours are rare, accounting for 0.4% of neoplasms found in the central nervous system [1]. Overall treatment
∗ Corresponding author. E-mail address: [email protected] (F. Proust).
strategies for these tumours vary significantly depending on the histological diagnosis and the midbrain compression responsible for obstructive hydrocephalus. Except for patients where elevated serum or CSF markers levels are diagnostic, histopathological identification is the answer to the management involving surgical resection or biopsy, radiation therapy and chemotherapy. The biopsy may be performed via open surgery, stereotactic or an endoscopic approach.
http://dx.doi.org/10.1016/j.neuchi.2015.03.001 0028-3770/© 2015 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
G Model NEUCHI-702; No. of Pages 4
ARTICLE IN PRESS D. Chaussemy et al. / Neurochirurgie xxx (2015) xxx–xxx
2
Endoscopy of pineal region tumours has been developed since the year 2000 [2–4] either via transventricular or extracerebral approach sometimes in complement to the microscopic exposure. Based on the literature, we review the different approaches and discuss the indication and limitations. 2. Different endoscopic procedures Neuroendoscopic procedures for brain tumours were initially developed as an approach to intraventricular lesions, in particular third ventricular tumours. However, progressively the endoscopic exposure of brain tumours used the anatomical fissure and the microscopic approaches either isolated or in combination with conventional optical magnification. 2.1. Transventricular technique The initial purpose of applying neuroendoscopy in the management of pineal region tumours was to resolve the obstructive hydrocephalus, and identify the pathological characteristics of the tumour [3]. Thus, the anterior neuroendoscopic approach is suitable not only to obtain tissue samples from multiple parts of the tumours but also to sometimes complete the procedure by a complete debulking of the tumour [5]. Under general anaesthesia, the patient is placed in a supine position with the head secured in a three-pin head holder. The patient’s head is not rotated and kept exactly vertical at 0◦ . The midline, as well as the coronal suture, is identified to create a hole giving access to both the third ventricle floor as well as the most posterior part of the third ventricle. This hole is performed on the pupillary line, 3 cm anterior to the coronal suture [6]. The choice of this burr hole can be determined using neuronavigation in order to obtain an optimal trajectory for both targets. The endoscope is then methodically checked with the scrub nurse (enlightenment, status of the instruments, balloon inflation). After subcutaneous adrenalin infiltration, a vertical skin incision will permit to perform a burr hole, bone cut waxed, dural opening and substantial washing with physiological serum. The endoscope cannula is gently implanted perpendicularly to the cortex toward the frontal horn of the right lateral ventricle. After obtaining cerebrospinal fluid (CSF), a rigid endoscope of 30◦ is introduced and secured into its holder. A CSF sample is then obtained for the dosage of pineal region tumour markers. Under endoscopic view, the anatomical landmarks of the lateral ventricle enabled to push the endoscope through the Monro foramen toward the third ventricle floor. The first step was to perform a ventriculostomy at the floor between the infundibular recesses anteriorly and the mammillary bodies posteriorly. Once the ventriculostomy is done, the endoscope should be gently rotated to the posterior part of the third ventricle in order to identify the anterior pole of the tumour. The neuronavigation could be helpful to confirm the good position of the endoscope tip in front of the tumour. After a careful coagulation of its surface, a biopsy of the tumour is performed using a biopsy rongeur. In case of removal of the tumour, some authors recommended a primary resection under careful haemostasis combining gentle irrigation and coagulation by bipolar coagulation. After, a standard endoscopic third ventriculostomy is completed via a second standard coronal burr hole [5]. 2.2. Extracerebral approaches These approaches are derived from the microsurgical pathway using an endoscope to expose the operative field in complete replacement of the operative microscope and sometimes in combination.
The endoscopic supracerebellar infratentorial approach was initially described to resect a pineal cyst [7], then applied to remove the tumour [8–10]. In the sitting position, the patient is secured to the rigid Mayfield frame. A 3-cm vertical incision followed by a microcraniotomy placed at the inferior margin of the transverse sinus permits a dural opening in a semi-lunar fashion. The gravity-based retraction of the superior surface of cerebellar hemisphere permits to position the endoscope in the infratentorial space via its holder. The endoscope is then advanced along the lower margin of the tentorium. The tentorial bridging veins are respected. On arrival at the deep venous confluence, the endoscope is directed towards the level of pathological entity and the coronally-oriented arachnoid adhesions opened and the dissection started using a bimanual technique. The instruments are independently used and do not pass through the endoscopic ports. Standard microsurgical instruments are used allowing a bimanual dissection under endoscopic view for optical magnification. Then, microdissectors, pituitary forceps, ultrasonic dissector can be conventionally used in order to perform a dissection. The principles of microsurgical resection can be proposed: Telfa cottonoids, gentle dissection, bimanual haemostasis, and use of haemostatic agents. Some authors have reported the use of 3D endoscopic technology (6.5 mm outside diameter, 0◦ and 45◦ endoscopes). The endoscopic approach for this indication has been considered a complement of the optic magnification to verify the complete characteristics of the resection. An interhemispheric transtentorial approach has been reported using the endoscopic procedure [9,11]. This latter mentioned procedure is the one most often proposed in complement to the microsurgical exposition. 3. Indications If the tumour markers AFP and HCG are undetected in serum and ventriculomegaly is found on imaging, neuroendoscopic surgery can be applied at least to resolve the CSF obstruction as well as to obtain a biopsy. The decision between biopsy and tumour removal is based on the tumour intrinsic characteristics such as bleeding, adherence and consistency. Neuroendoscopic procedures can be considered as a therapeutic alternative to the microsurgical approach. 4. Advantages The endoscopic approach is considered a minimally invasive procedure because of the usefulness of the corridor up to the tumoral target, whether it is transgyral or not. These small corridors permit to respect the bridge veins through the pathway, contouring these obstacles to the tumour. The corridors, which condition an accurate view trajectory, require only a small craniotomy and minimal brain retraction. Neuronavigation is a useful tool to optimize the optical view. This procedure decreases the exposure of the functional area as well as the risk of neurological consequences related to the approach. The tip of the endoscope located close to the tumoral process provides an excellent view for intraoperative diagnostic analysis. This type of optical magnification allows resection control behind the venous structures, i.e., internal cerebral veins and optimization of the microdissection. As regards bimanual dissection, under endoscopic control, the overload of the operative field is reduced. Exoscope systems or VITOM-90 are hybrid devices inspired by a combination of quality from the endoscope and operative microscope [12]. The VITOM90 is a rigid rod lens system that looks and functions much like
Please cite this article in press as: Chaussemy D, et al. Interest and limits of endoscopic approaches for pineal region tumours. Neurochirurgie (2015), http://dx.doi.org/10.1016/j.neuchi.2015.03.001
G Model NEUCHI-702; No. of Pages 4
ARTICLE IN PRESS D. Chaussemy et al. / Neurochirurgie xxx (2015) xxx–xxx
a standard endoscope with a long focal distance of 25–30 cm, and therefore is positioned outside the operative cavity. This new technology, as an alternative to the microscopic approach, is attached to a high definition digital camera and displayed on HD video monitor, and has been reported in pineal tumour resection [12]. Moreover, a bimanual manipulation also required conventional instruments which are used for open surgery.
3
can be blood contamination resulting in a perforation risk of the third ventricle floor. This approach exposes patients to difficult pathological reading and false negative results due to the small biopsy size using micro forceps. The rate of non diagnostic or inaccurate diagnosis has been reported to range from 52% to 70% [9]. 6. How to avoid complications?
5. Limitations The limitations of these procedures are classified into those related to the procedure and those related to the tumour. 5.1. Related to the procedure The endoscopic procedure can be performed either in monohand or bimanual manipulation, which exposes different adverse events. In the first case, the long instruments are dedicated for this procedure, and introduced by an intra-endoscopic channel. The consequences of this monohand working were not only the difficulty in dissecting the tumour and achieving haemostasis but also the possibility to transform the endoscopic approach into open surgery. The bimanual dissection was more adaptable to the demands of the interface between the tumour and the surrounding functional area. Nevertheless, the magnified operative field did not allow to control the instrument introduction along the pathway to the target. Furthermore, these successive introductions of instruments during the resection expose functional structures along the surgical corridor to injury. The working with one’s hands, and not within the axis of the viewed trajectory directed on to the screen, required learning curves. In other words, the magnified operative field was projected at distance from the hands. 5.2. Related to the tumors All the difficulty in surgery was related to intraventricular bleeding, the morphological characteristics of the tumour and the dissemination risk related to its pathology. The intraoperative bleeding was directly related to the vascularisation of the tumour. Excessive bleeding subsequently obscured vision making the pursuit of debulking and exposure to occlusion of the ventriculostomy difficult [4]. This bleeding might also occur due to surgical injury of interthalamic adhesion [3]. Some haemorrhagic complications such as intratumoral haemorrhage can complicate the ventriculostomy which is probably due to the sudden decrease of intracranial hypertension (ICH) [13]. Similarly, the ventricular collapse after debulking can be responsible for a subdural haematoma [14]. The morphological characteristics of the tumour such as size and consistency are determining factors for the debulking. Tumour size could also constitute a limiting factor, because it has been considered that this type of procedure was not suitable for tumours larger than 2.5 cm [9,14,15]. Moreover, the excision might be difficult to perform due to its hard consistency. The most suitable presentation is soft tissue which is slightly vascularized and, therefore, more easily aspirated [11]. In this last situation, the tumour size was less elementary for the excision. The CSF dissemination rate of pineal lesions is a risk depending on the tumour type which can reach up to 47% of cases [15]. The rationale would be to keep the subarachnoid space isolated during the biopsy with an abundantly rinsed ventricle [5,15]. The ventriculostomy is performed in a second intention, but the risk
Vigilant preoperative assessment of imaging examinations is required to analyse the difficulties encountered during the resection: distance from the cortex to the frontal horn, position of basilar tip close to the third ventricle floor, anterior protrusion of the tumour into the third ventricle, upward extension of the tumour under the splenium of corpus callosum. The operative checklist must be scrupulously verified: light source, white balance, disposition of instruments, possibility of warm saline irrigation, verification of the permeability of the system in order to avoid any ICH. A surgical assistant must also be present to secure the endoscope holder and manage the irrigation system. Large sheaths are required to use large forceps and a bipolar tip, to obtain a large size biopsy, dissection manoeuvres from the venous system with no tumour traction in order to avoid venous injury. In the bimanual dissection, the endoscope fixed on its holder must permit a wide view of the pathway. For this reason, the exoscope was considered a response to meet this requirement. Intraoperatively, meticulous evaluations are required to select the optimal strategy to perform biopsy alone, or debulking and decide to stop the procedure based on intraoperative conditions. Rules must be careful applied: never use traction, step-by-step haemostasis, gentle dissection and do not hesitate to make the transition to open surgery if conditions become difficult. 7. Conclusion For pineal region tumours, the endoscopic approach constitutes a recent alternative to open microscopic surgery. Considered as mini-invasive procedure because of the thin corridor as a surgical approach, this procedure due to the quality of its exposure resulted in extensive dissection exposing the procedure to neurological consequences. If the monohand manipulation remained a risky gesture, bimanual dissection was a subsequently derived application based on the microsurgical techniques in this process of optical magnification. The future could be an operative field magnification using these devices which are positioned outside the surgical cavity. Financial support None. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. References [1] Pettorini BL, Al-Mahfoud R, Jenkinson MD, Avula S, Pizer B, Mallucci C. Surgical pathway and management of pineal region tumours in children. Childs Nerv Syst 2013;29(3):433–9. [2] Robinson S, Cohen AR. The role of neuroendoscopy in the treatment of pineal region tumors. Surg Neurol 1997;48(4):360–5 [discussion 5–7]. [3] Oi S, Shibata M, Tominaga J, Honda Y, Shinoda M, Takei F, et al. Efficacy of neuroendoscopic procedures in minimally invasive preferential management of pineal region tumors: a prospective study. J Neurosurg 2000;93(2):245–53. [4] Chernov MF, Kamikawa S, Yamane F, Ishihara S, Kubo O, Hori T. Neurofiberscopic biopsy of tumors of the pineal region and posterior third
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