“Picket fence” an alternative clipping technique for wide necked and large aneurysms: technical nuances in a case series
Article information
Abstract
Complex aneurysms are a therapeutic challenge in contemporary neurosurgery. Several microsurgical and endovascular techniques have been proposed for their treatment. The picket fence clipping technique uses fenestrated clips, that are stacked not to reconstruct the neck of the aneurysm, but to create a duct to normalize the cerebral flow by reconstructing the dome. We present four illustrative cases using the picket fence clipping technique. The aneurysms considered were of different locations (ICA, MCA, AComA), of large or giant size with wide necks, in which clipping attempt with a conventional technique was not possible, so that the use of non-conventional clipping techniques had to be applied with favorable results. In our experience we found this technique useful in large and giant, wide-necked aneurysms by reconstructing the parent vessel according to the concept of the ideal closure line in these previously unreported locations, thereby restoring normal cerebral circulation. The use of non-conventional techniques for clipping complex aneurysms can be used alone or in combination for adequate treatment, preserving cerebral circulation without compromising adequate exclusion of the aneurysm. The Picket fence technique is a feasible clipping technique that can be used as a less morbid option in large and giant aneurysms with wide necks.
INTRODUCTION
Cerebral complex aneurysms are among the most challenging and difficult to treat lesions in neurosurgery. Factors inherent to the aneurysm have been identified that determine that its treatment has a degree of complexity greater than usual, such as location (brain regions difficult to access), shape (fusiform or wide neck), size (from extremely small or large and giant aneurysms), etiology (fungal or traumatic), content (aneurysms with intraluminal thrombus or with atherosclerotic or calcified wall) and the presence of associated arterial or perforating branches [3,4].
When clipping an aneurysm, the philosophy should be to preserve normal cerebral circulation and to occlude the entire aneurysm neck as simply as possible. This can be achieved in most aneurysms with a single clip, but for complex aneurysms, this is not an absolute truth and multiple clipping techniques have been proposed.
Since their design and application by Drake, fenestrated clips have represented an important advance for the treatment of complex aneurysms allowing the reconstruction of the neck of an aneurysm while preserving the patency of adjacent vessels. Later, with the description of new techniques, its use has expanded with favorable results [2]. In 2008 Yang and Lawton described a new technique using fenestrated clips, stacking them not to reconstruct the neck of the aneurysm but with the purpose of creating a duct to normalize the cerebral flow isolating the aneurysm from the circulation. The above by means of three methods: antegrade, retrograde and by reconstruction of the dome with straight fenestrated clips applied from dome to neck (picket fence) [1,11]. The reverse picket fence technique is used in aneurysms where the dome is directed far away from the neurosurgeon, so the clips are stacked from neck to dome [7,8].
We aim to describe our experience using the picket fence and reverse picket fence techniques in four illustrative cases of complex aneurysms.
CASE DESCRIPTION
A descriptive clinical study with retrospective analysis of the aneurysm cases treated with the “picket fence” and “reverse picket fence” techniques during the period from January 2018 to January 2023 in a vascular neurosurgery department. For the purposes of this report, it was obtained demographic data, clinical characteristics, pre and postoperative imaging studies, and videos of the surgical procedure of the patients, as well as their evolution. Before the entrance to the hospital, each patient / relative signed an informed consent to his treatment. During the elaboration of this report, the patient’s confidentiality was preserved, and it was carried out in accordance with the ethical principles of the Helsinki declaration. Local Ethical Committee approval was obtained for the present study.
RESULTS
From a total of 454 aneurysms treated microsurgically by senior author, 11 cases have been treated with the picket fence and reverse picket fence techniques during the period time (Table 1).
Case series of García-López et al. and reported cases in PUBMED treated with picket fence and reverse picket fence clipping techniques
Case 1: A 33-year-old male with history of tobacco, alcohol, and amphetamine consumption suddenly developed headache, decreased alertness, and seizures. In emergency room (ER) exploration was found with Glasgow coma scale (GCS) of 7 points, and computed tomography (CT) scan showed Fisher 4 subarachnoid hemorrhage (SAH). A giant bilobed aneurysm of the right middle cerebral artery (MCA) bifurcation and a complex aneurysm of the anterior temporal artery (ATA) were identified on digital subtraction angiography (DSA). It was decided to perform the picket fence technique. Punction and aspiration of the dome was performed, with temporary clipping in the M1 and M2 frontal and temporal branches. Reconstruction began with a 15 mm straight clip to reduce the volume of the dome and facilitate reconstruction. Subsequently, fenestrated clips were applied following ideal closure line. Finally, the ATA aneurysm was clipped with a 7 mm semi-curved clip. Under direct vision, a third ventriculostomy was performed with placement of a ventricular catheter for seven days. Postoperative DSA showed patency of the vascular tract with reconstruction of the vessel and adequate distal perfusion. The patient was discharged with left hemiparesis, which improved at the 12-month follow-up (Fig. 1).
Case 1 (A) Axial CT shows a Fisher 4 SAH in the basal cisterns. (B) Angio-CT showing a giant M1 bifurcation aneurysm with dome dependent M2 frontal and temporal branches. (C) Posterior view of a digital reconstruction showing a fusiform ATA aneurysm. (D) Operative view of a trans- sylvian approach after dissection of the M1 bifurcation-dependent aneurysm. (E) To reduce the volume of the dome and identify the closure line, the aneurysm was trapped and aspirated. (F) A clip is then placed to modify the geometry of the dome and (G) the remaining clips are stacked to reconstruct the parent artery and its efferent branches. (H) Postoperative DSA shows adequate patency of the distal vessels and complete exclusion of the aneurysm from the cerebral circulation (I). CT, computed tomography; ATA, anterior temporal artery; DSA, digital subtraction angiography
Case 2: A 61-year-old female patient with a history of hypertension and cannabinoid use. Seventy-two hours before presenting to ER, she debuted with sudden deterioration of alertness with recovery in 30 minutes but with sequelae of global aphasia, right hemiparesis, and left nasal hemianopia. The DSA shows a global giant ventral paraclinoid aneurysm, so a pterional approach with an extradural anterior clinoidectomy was decided, with distal dural ring aperture for temporary control in clinoid internal carotid artery (ICA). In a first attempt, a 90° fenestrated clip was placed under proximal control; however, when the temporary clip was removed, the fenestrated clip was displaced by the strong flow of dome, reducing the caliber of the supraclinoid ICA. Reverse picket fence technique was used with seven fenestrated straight clips for reconstruction of the supraclinoid segment with proximal control in the clinoid segment with a temporary clip. To reduce the volume of the dome, a 15 mm sagittal clip was placed. In contraposition to the first reconstruction, four clips were placed, achieving complete dome obliteration. Post-surgical DSA confirmed complete reconstruction of the vessel with permeability of ICA and its terminal branches. In the follow-up, the patient remained with visual field deficit but with motor and language recovery (Fig. 2).
Case 2 (A) Digital reconstruction of AngioCT, (B) DSA and (C) digital reconstruction of DSA showing a giant paraclinoid aneurysm with ventral projection. (D) Operative view after dissection of the basal cisterns showing the aneurysm and the ICA with its terminal branches ACA and MCA. (E) Operative view after clinoidectomy and opening of the distal dural ring for proximal control. (F) First attempt of conventional clipping with a fenestrated clip angled at 90°, which under proximal control shows patency of the distal branches (MCA, ACA and AChoA), but after removal of the temporary clip, (G) the flow of the aneurysm displaces the clip from its original position. (H), (I) The reverse picket fence technique is started from proximal to distal with placement of straight fenestrated clips from the neck to the dome. (J) To verify the adequate exclusion of the aneurysm, puncture and aspiration are performed, observing permeability of aneurysm, so reconstruction is continued. (K) Reconstruction of the dome with placement of clips preserving the AChoA (L). In the post-operative, frontal view (M), oblique view (N) and lateral view (O) of the DSA, in which the distal cerebral circulation is observed without residual aneurysm. CT, computed tomography; DSA, digital subtraction angiography; ICA, internal carotid artery; ACA, anterior cerebral artery; MCA, middle cerebral artery; AChoA, anterior choroidal artery
Case 3: An 83-year-old female patient with a history of hypertension and hepatitis C, with chronic headaches, in whom an aneurysm dependent on the bifurcation of the MCA was discovered incidentally. During the procedure, after dissection of the Sylvian valley, the aneurysm was identified. Reconstruction began with a straight non fenestrated clip, placed with the tip in the ideal closure line to reduce the size and modify the geometry of the dome. Then four more straight clips were stacked. In the neck, a remnant was identified near the temporal branch, so it was decided to place a curved miniclip. Postoperative AngioCT confirmed adequate reconstruction of the vessel with patency. The patient was discharged and had an independent 6-month follow-up without deficit (Fig. 3).
Case 3 Posterior (A), anterior (B), and superior view (C) of digital reconstruction of an Angio CT showing an aneurysm of the M1 bifurcation which shares the neck with the M2 temporal branch. (D) Operative view after dissection of the Sylvian valley showing the aneurysm with atheroma plaque in the neck. (E) Dissection of the aneurysm shows involvement of the M2 temporal branch by continuity of the neck. (F) Under proximal control of M1, a first clip is placed perpendicular to the neck in the center of the dome to reduce the volume and identify the line of ideal occlusion. (G) Stacked clips are placed on the ideal closure line, obliterating the neck of the bifurcation. (H) The remnant is observed in the neck attached to the temporal M2. (I) Finally, a curved miniclip is placed to complete the remodeling of the parent vessel and distal M2 branches. (J) Final surgical view after removal of the temporal clip with adequate patency of the distal branches. (K) Posterior oblique view and (L) and posterior AngiCT reconstruction showing patency of the anterior and temporal M2 branches with adequate exclusion of the aneurysm. CT, computed tomography
Case 4: A 60-year-old woman with a history of rheumatoid arthritis and chronic use of acetylsalicylic acid. She presented to the ER with thunderclap headache and syncope. A subarachnoid hemorrhage, Fisher 4, Hunt and Hess 2 was identified during the approach. AngioCT showed four aneurysms, the first dependent on the anterior communicating artery (AComA), the second on the AChoA, the third blister in the bifurcation of the ICA, and the fourth in the bifurcation of the right MCA. Therefore, reconstruction was started via a right pterional approach and cisternal dissection. The AComA aneurysm had an atheroma plaque in the dome and its neck continued with the A2 segment of the anterior cerebral artery (ACA), so a first clip was placed in the neck portion at A2. Then, to avoid the atheroma in the dome, a straight fenestrated clip was placed with the tip at the neck of the aneurysm, then one curved and two straight clips were stacked to reconstruct the ideal closure line. In the anterior choroidal artery (AChoA) aneurysm, a 3 mm straight miniclip was placed. For the blister type aneurysm, the muscle wrapping technique was used. Finally, for MCA bifurcation aneurysm, a first straight clip was placed in the center of the dome to reduce the volume and change the shape of the aneurysm, then 3 straight clips and 1 curved clip were stacked to reconstruct the vessel. Postoperative AngioCT showed adequate vessel patency and the patient was discharged with mild hemiparesis, which improved at one year follow-up (Fig. 4).
Case 4 (A), (B) Superior and lateral view of the AngioCT reconstruction showing aneurysms in the AComA, AChoA, ICA and M1 bifurcation. (C) Operative view of the anterior communicating complex showing an AComA-dependent aneurysm sharing the neck with the A2 branch. (D) Reconstruction from the dome to the neck is started by dividing the neck portion of A2. (E) Reconstruction is continued with fenestrated clips to exclude atheroma plaque in the dome. (F) More clips are stacked to reconstruct the AComA. (G) Operative view of the M1 bifurcation aneurysm. (H) A first clip is placed in the center of the dome to modify the shape of the aneurysm. (I) Clips are stacked from the dome to the neck to complete the reconstruction of the frontal and temporal M2 branches. (J) Post-operative lateral view in Angio CT reconstruction, (K) superior oblique and (L) superior view showing adequate exclusion of aneurysms with distal vessels patency. CT, computed tomography; AComA, anterior communicating artery; AChoA, anterior choroidal artery; ICA, internal carotid artery
DISCUSSION
In this paper, we present illustrative cases of our experience using the Picket Fence and Reverse Picket Fence techniques, which we have found to be particularly useful in large and giant aneurysms in paraclinoid segment of ICA and MCA bifurcation. It is also useful in cases when a conventional clipping technique is not feasible with a single clip or presence of distal branches are firmly attached to the aneurysm dome.
The concept of the ideal closure line and ideal closure plane for clipping an aneurysm is important to every vascular neurosurgeon to avoid the risk of ischemic complications and future recurrence [5]. The ideal closure line is a 2-dimensional curved line created by converting the 3-dimensional curved sphere of the aneurysm into a 2-dimensional line [5,7]. We advocate the use of this concept for aneurysms in any location. The concept of ideal closure line in wide-necked and large or giant aneurysm cannot be achieved with a conventional clipping technique. Combination of clipping techniques may be required to achieve adequate neck closure.
Throughout history, multiple techniques have been described for the treatment of complex aneurysms. In his classic text on aneurysms, Yasargil proposed the reduction of the dome of giant aneurysms to adapt the shape for proper clipping by bipolar coagulation. This technique allows to reduce and reshape the dome and the neck of the aneurysm, facilitating the clipping, but he warns that it can generate such a weakness that it can lead to surgical rupture, and it should not be used in those aneurysms in which the dissection of the surrounding branches is not complete, in aneurysms with very wide, sclerotic or calcified bases or those that are thrombosed [12].
Tandem clipping was one of the first procedures described, in which one clip is placed parallel to the parent vessel, and once the volume of the dome has been reduced, stacked clips are placed below (understacking) or above (overstacking) the first clip to reinforce the clipping [6]. Dr. Sano’s group advocates placement of a clip in the most distal and deepest part of the dome near the neck to reduce the volume of the aneurysm and the size of the neck, with subsequent placement of clips to reinforce the clipping. The volume of the aneurysm, which can be reduced by temporary clipping, aspiration, or trapping, is the main obstacle to this method [9]. In contrast, Dr. Kurita’s group proposed the “mass reduction clipping technique” using a first fenestrated clip, perpendicular to the parent vessel at the center of the dome to reduce the aneurysmal volume, changing the conformation to easily complete the clipping. Unlike the picket fence technique, the clips are not placed stacked with respect to the first clip, but under the concept of the ideal closure line, the clips are placed parallel to the neck to reduce the number of clips used and the potential transient clipping time [10].
The use of fenestrated clips for multiple clipping allows vessels to be reconstructed through the fenestrae or otherwise contain atheroma plaque or calcium from the dome walls without losing tip closure strength, in cases where the dome is not bulky, stacked non-fenestrated clips can be used for aneurysm reconstruction. The combination of techniques such as the mass reduction technique with a first fenestrated clip at the center of the dome can modify the aneurysm geometrically, allowing the remaining neck to be completed with the picket fence technique.
As shown in case 2, simple clipping of a giant aneurysm with a wide neck is not feasible due to hemodynamic conditions. In the first try, under proximal control, clipping was attempted with a single fenestrated clip angled at 90°, but when the proximal control was removed, the clip was displaced by pressure within the parent artery. While it is true that the tip is the weakest part of the clip, stacking these allows for better reconstruction following the ideal closure line and increases occlusion pressure in the neck of the aneurysm.
Although we have not seen any recurrences or clinical consequences of mass effect due to the multiple clips in surrounding structures with this technique, in our series with a maximum follow-up of 60 months, it is important to follow the patient in the long term. We can point out some potential problems with this technique. First, the increased cost of the treatment, is an important factor in developing countries. Second, based on the physics of fluids and assuming that each clip tip has the same pressure; single parallel clips create a uniform pressure along the neck, whereas perpendicular Picket Fence clips create a heterogeneous pressure that alternates between tip pressure and a zone of zero pressure. If an aneurysm recurs with the Picket Fence technique, it will be probably at the points between each clip where the pressure on the vessel wall is lowest. Another issue that may arise with the use of this technique is the potential volume effect of the clips on adjacent vascular and neural structures.
CONCLUSIONS
The vascular neurosurgeon should always have endovascular or bypass revascularization techniques for complex cases, but the picket fence is a feasible technique that can be used as a less morbid option in large and giant aneurysms with wide necks. The ideal closure line concept is applicable to aneurysms in any location to reconstruct the parent vessel, regardless of the clipping technique used.
Acknowledgements
Mara Lamothe. For her contributions to improve the text.
Notes
Disclosure
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.