External guide for safe orthogonal approach

Transcription

1 External guide for safe orthogonal approach Poster No.: C-0768 Congress: ECR 2017 Type: Scientific Exhibit Authors: M. SEOL, J. CHOI, H. KIM ; Jeonju, Jeonrabukdo/KR, Jeonju/ KR Keywords: Ischaemia / Infarction, Haemorrhage, Surgery, Intraoperative, Contrast agent-other, Conventional radiography, Catheter venography, Neuroradiology brain DOI: /ecr2017/C Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 17

2 Aims and objectives Most common complication of intracranial surgical approach is vascular compromise and of these most are induced by venous injuries [1, 2]. 70% of cerebral blood volumes are pooled in cerebral veins and cerebral venous drainage are very complicated and variation is high between individuals [1]. Multiple veins over the lateral surface of the cerebral hemisphere has role of forming anastomosis between superficial and deep venous system [1-4]. These can be divided into three main groups: the superior anastomotic vein or vein of Trolard (VT), the inferior anastomotic vein or vein of Labbé (VL), the superficial middle cerebral vein or superficial sylvian vein (SSV). The VL, having a diameter of mm, is the largest vein of the temporal lobe lateral surface veins, mostly originating from the middle portion of the lateral sulcus and runs along postero-inferior course, connecting lateral sulcus veins via transverse sinus. The SSV is formed from anastomosis of the temporo-sylvian veins, with a diameter of mm, and usually drains to the cavernous sinus or the sphenoparietal sinus, and shows multiple variation in size and connections [4-8]. The position of the VL is clinically important when having to perform lateral access to skull base or posterior temporal approach to investigate medial tentorial lesions [1, 4, 5]. SSV is important when pterional approach is needed [8]. There are many anastomotic veins over the cortex and when these veins are damaged during surgery does not necessarily mean severe neurological complication, but especially in the cases where the VL exists as single dominant vessel form (20~40%) draining majority of the temporal lobe or lateral cerebral hemisphere, damage to the VL can lead to serious complications such as brain edema, venous infarction and hemorrhage and affects patient morbidity [1-4, 9, 10]. Moreover it has been reported clinically that it can induce neurological sequelae such as aphasia, hemiparesis, facial paresis, pyramidal signs, and even death [2]. In the case of the SSV, when large caliber SSV is damaged, venous infarction or contusion of the frontal lobe can occur [6] and rarely it can induce seizure or facial palsy [4, 8]. Therefore, it is important to identify and preserve these veins in order to prevent iatrogenic injury. Orthogonal approach, meaning for accessing the brain through the lateral surfaces on operation, is a useful route to evacuate the intracerebral hematoma or to implant the depth electrodes in epilepsy patients or to perform biopsy for intracranial mass lesions. However, variable courses of venous structures on the lateral surface of the cerebral hemisphere sometimes can induce unwanted complications such as subarachnoid or Page 2 of 17

3 subdural hemorrhage during the procedure. Hence, the possible means to avoid these complications should be required. Previous studies of superficial cerebral veins used cadaveric, radiographic, microsurgical evaluation to evaluate anatomic variation or anatomic course of the vessels, however study about using geometric external landmarks over the head surface to avoid certain veins are not many. Aim of this research is to aid neurosurgeons in the operation room performing general neurosurgeries via orthogonal approach, in rapidly identifying the position of the Sylvian vein and vein of Labbe, allowing to find safe approaching window, and thus decreasing postoperative complication rates. Page 3 of 17

4 Methods and materials In the last 12 months, of those cerebral angiographic studies performed at the Presbyterian Medical Center, patients without intracranial or intratemporal pathologic lesion were selected, and then from these images, images with clear SSV and VL were selected and combined. 17 male, 17 female, 34 patients in total satisfied this condition and were selected for this study. Age of 17 males ranged from years old, and average age was Age of 17 females ranged from years old, and the mean age was Age of all the 34 patients ranged from years old and the mean was 61.1 years old. Venous phase of frontal and lateral projection images were obtained showing the dominant VL. In this study, only lateral projection image was used for standard perspective. The VL and SSV were selected in each lateral projection images by staff neuroradiologist and then the location information of the VL and SSV were edited with the Photoshop. The process is as follows: boundaries of the lateral skulls were realigned to fit together with reference points of coronal suture and pituitary fossa, and subsequently venous structures were overlaid (Fig. 1). Page 4 of 17

5 Fig. 1: Redrawn and summated the Sylvian veins and vein of Labbé from the transferred angiographic images of the 34 patients are shown. The coronal suture (yellow arrowhead) and the pituitary fossa (blue arrowhead) were used as a reference point for summation. References: Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR The external auditory canal (EAC) and glabella were used as anatomical landmarks. The mid-point of the line connecting EAC with the glabella was used to draw the circle (Sylvian circle : SC). Line connecting the EAC with the coronal suture (Labbé Line : LL) was drawn. The zone (Labbé zone : LZ) between the LL, SC and the line connecting the internal occipital protuberance and EAC was made (Fig. 2,3). Page 5 of 17

6 Fig. 2: The Sylvian circle (SC) starts from the mid-point (red arrowhead) of line connecting the glabella (pink arrowhead) and the external auditory canal (EAC) (green arrowhead). The line of Labbé (LL) connects the coronal suture (yellow arrowhead) with the EAC. The Labbé zone (LZ) between the LL, SC and the line connecting the internal occipital protuberance and EAC was made. References: Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 6 of 17

7 Fig. 3: The SC and LL show their positions on the lateral skull view with real courses of the Sylvian veins and vein of Labbé. References: Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Distribution percentage of the SSVs along the SC and the VLs within the LZ were counted. Page 7 of 17

8 Images for this section: Fig. 1: Redrawn and summated the Sylvian veins and vein of Labbé from the transferred angiographic images of the 34 patients are shown. The coronal suture (yellow arrowhead) and the pituitary fossa (blue arrowhead) were used as a reference point for summation. Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 8 of 17

9 Fig. 2: The Sylvian circle (SC) starts from the mid-point (red arrowhead) of line connecting the glabella (pink arrowhead) and the external auditory canal (EAC) (green arrowhead). The line of Labbé (LL) connects the coronal suture (yellow arrowhead) with the EAC. The Labbé zone (LZ) between the LL, SC and the line connecting the internal occipital protuberance and EAC was made. Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 9 of 17

10 Fig. 3: The SC and LL show their positions on the lateral skull view with real courses of the Sylvian veins and vein of Labbé. Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 10 of 17

11 Results The SSVs of all patients were all located within a 10 mm range of the SC. Especially SSVs of 27 patients (79.4%) were within a 5 mm range from the SC. In addition, 5 SSVs (14.7%; 4 male, 1 female) were located further than 5 mm from the SC and 2 SSVs (5.8%; 2 male) closer than 5 mm from the SC. Most of the VLs were distributed in the LZ (94.1%; 16 male, 16 female). The fan-shaped zone formed by the skull base anteriorly, the SC superiorly, and the LL posteriorly contains less distribution of the veins than a 5 mm range of the SC or the LZ (Fig. 4). Fig. 4: 79.4% of the Sylvian veins are located within a 5 mm range of the SC (red curved cylinder-shaped zone). The LZ (blue fan-shaped zone) contains most of the vein of Labbé (94.1%). The fan-shaped zone formed by the skull base anteriorly, the SC superiorly, and the LL posteriorly contains less distribution of the veins than a 5 mm range of the SC or the LZ. References: Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 11 of 17

12 Images for this section: Fig. 4: 79.4% of the Sylvian veins are located within a 5 mm range of the SC (red curved cylinder-shaped zone). The LZ (blue fan-shaped zone) contains most of the vein of Labbé (94.1%). The fan-shaped zone formed by the skull base anteriorly, the SC superiorly, and the LL posteriorly contains less distribution of the veins than a 5 mm range of the SC or the LZ. Radiology, Seonam University, Presbyterian Medical Center - Jeonju/KR Page 12 of 17

13 Conclusion The cerebral venous structure can be divided into the superficial and deep system. The superficial system includes cortical veins that drain blood from outer 2cm cortex and underlying white matter to one of several dural sinuses [2, 9]. The superficial anastomotic veins of the lateral brain surface is composed of the vein of Trolard (VT), vein of Labbe (VL), and superficial sylvian vein (SSV) [1, 2, 4, 7]. The VL originally meant veins that connect the transverse sinus and other supratentoral venous system like the sylvian veins or VT. Currently the VL refers to the large vein on the lateral aspect of the temporal lobe [1, 2]. The VL comes in multiple variations in size and drainage pattern [1, 4, 5]. The VL usually have diameter of 3.2mm ( mm) and most of them arise from the middle portion of the Sylvian fissure and then head to the posterior and inferior direction to the anterior part of the transverse sinus [1, 7]. Shoman et al. [2] reported that according to the brain angiographic study results, 86.4% of the VL was in the temporal bone, 60% in the middle temporal area, 30% in the posterior, and 10% located more anteriorly and the VLs showed highly variable courses. More than 90% of the VL drains blood from the lateral surface of the temporal lobe and sylvian fissure region and empties to the transverse sinus, transverse tentorium or superior sigmoid sinus [1, 2]. The VL is important in presigmoid transpetrosal approaches due to injury risk [2] and especially when the VL runs close to the tentorium or if there is a tentorial division, intradural segment can become vulnerable [1, 9]. Cerebral vascular complication incidence rate during skull base surgery has been reported to be 5-18% and this is the third most frequent complication following damage of arterial circulation or cerebral edema relatively [2]. Damage or injury of the cortical veins of the lateral temporal lobe can induce venous infarcts, hemorrhages, and neurologic complications [2]. Venous sinus occlusion raises intracranial pressure and induces diffuse cerebral swelling and can also lead to cerebral ischemia and/or hemorrhagic infarction [2]. These complications will occur with higher incidence rate in the presence of the dominant VL [2]. Lustig et al. [9] reported on a 55-year-old woman who was performed a combined middle and posterior fossa approach for removal of a left petroclival meningioma. Intraoperatively, a large VL contiguous with the disrupted sinus was noted. Postoperatively, the patient was minimally responsive and had a right hemiparesis. A first post-operative brain computed tomography (CT) scan revealed a venous infarct in the left temporal lobe. The SSV is composed of fronto-ortital (fssv), fronto-parietal, and anterior temporal (tssv) veins and have three drainage patterns: 1) absent or very hypoplastic, 2) single Page 13 of 17

14 main stem draining into the sphenoparietal sinus, 3) two main stems (fssv and tssv) draining into the sphenoparietal sinus and shows frequent variations [6]. Diameter of the SSV is 2.6mm ( mm) [7, 8], and shows asymmetrical size between right and left cerebral hemispheres [7]. The SSV usually originates from the posterior end of the Sylvian fissure and runs anteriorly and inferiorly along the lip of fissure, receives blood flow from the frontosylvian, parietosylvian and temporosylvian veins and usually forms anastomosis with the VT and VL. If the SSV is small or absent, the adjacent veins receive the drainage instead [7, 8, 12]. Especially during pterional approach, SSV has surgical importance as when it is damaged it can induce venous infarction or hemorrhage and lead to severe and irreversible neurologic deficits [6, 8]. The VL and SSV have variable anatomic configuration showing various collateral circulations and flow dominance patterns. Although lateral side approach of the brain is a common procedure to approach the temporal lobe and basal ganglia lesion, it can accompany critical post-operative complications such as iatrogenic venous damage [1]. Generally veins are more tortuous and composed of thinner walls than arteries and thus it is more vulnerable to damage and it is more difficult to manipulate before rupture [11]. Therefore pre-operative planning aiming to identify and preserve the intracerebral venous structure is vital and also surgeon must be familiar with superficial anastomotic venous anatomy to avoid possible complications. This has been very difficult as there has been no research on practical guide about cortical venous distributions yet. One of the common nerurosurgical method, orthogonal approach is a simple and efficacious route to evacuate the intracerebral hematoma, and it is used to implant the depth electrodes in epilepsy patients. Despite the simplicity and accuracy of the procedure, the orthogonal approach has often been abandoned due to unexpectable iatrogenic complications. Until now, to avoid postoperative complications, we relied on the double contrast media enhanced preoperative CT and surgeon's skills and experience. In the present study, we propose the practical external guidance system to prevent these post-operative complications such as subarachnoid or subdural hemorrhage due to injury of the SSV or VL. We edited conventional angiographic images of cerebral vessels using Photoshop. Then we compared edited image with visible external landmarks of the head and created artificial lines (SC, LL) and an artificial zone (LZ). 79.4% of the SSVs are located within a 5mm radius of the SC and most of the VLs are located within the LZ. The fan-shaped zone with boundaries of the skull base anteriorly, the SC superiorly and the LL posteriorly contains much less number of veins compared to two areas discussed above. Therefore, when orthogonal target points are placed adjacent to the SC and LZ, this means that they are likely to be placed on the SSVs or VLs indicating high probability of damaging these veins. If the targets are moved away from the SC and LZ, it means safer orthogonal procedure, especially within the fan-shaped zone. Since the SC and LZ can be easily drawn and can show its geometric relationship clearly in the operation Page 14 of 17

15 room, the SC and LZ could be used as an effective practical external guide for general neurosurgeries. Correct orientation for any neurosurgical approach begins with examination of the superficial anatomic landmarks. We researched method to identify distributional pattern of the SV and VL and showed that this will be a useful practical guide for surgical approach in general neurosurgeries. Page 15 of 17

16 Personal information MYUNGJIN SEOL, Department of Radiology, Presbyterian Medical Center, Seonam University, Jeonju, S. Korea; JINOK CHOI, Department of Radiology, Presbyterian Medical Center, Seonam University, Jeonju, S. Korea; HYOJOON KIM, Department of Neurosurgery, Presbyterian Medical Center, Seonam University, Jeonju, S. Korea; Page 16 of 17

17 References Page 17 of 17