On occasion, the wall of the aneurysm base can be the rupture site of the lesion, which poses a unique challenge for treatment. Although there has already been a report of the angiographic depiction of a basal rupture of a saccular aneurysm by a small outpouching at the aneurysm neck, this is the first report of saccular aneurysms in which a basal rupture was angiographically depicted as a stalk-like narrow neck due to a thrombus sealing the rupture point and occupying the lumen of the aneurysm base. The author reports on 2 such cases: a 49-year-old woman who presented with a basal rupture of a saccular aneurysm arising at the middle cerebral artery bifurcation, and a 44-year-old man who presented with rupture of a saccular aneurysm arising at the junction of the A2 segment and the anterior communicating artery. In both cases, a pterional craniotomy allowed the surgeon to determine that the base of the aneurysm was ruptured, and he surgically obliterated the aneurysm. Microsuture reconstruction and clipping of the aneurysm neck were successful in obliterating the ruptured aneurysm and avoiding any compromise of the parent artery.
The occurrence of an angiographic dimple or irregularity due to indentation of the contrast column by an intraluminal thrombus at the dome of a ruptured aneurysm is not uncommon and does not draw much clinical attention. However, an angiographic dimple at the base of the ruptured aneurysm or division of the parent artery can signify a rupture point close to the dimple and an intraluminal thrombus, which has utmost clinical significance as it is close to the parent artery and necessitates a different treatment strategy from rupture of the aneurysm dome. The author reports on 2 cases of an angiographic dimple following subarachnoid hemorrhage (SAH) and subsequent surgical exploration. In the first patient, a 57-year-old-woman, angiography revealed a basal dimple in a superiorly directed anterior communicating artery aneurysm. A pterional craniotomy was performed, which revealed a bilobed aneurysm harboring a superiorly directed unruptured lobule and inferiorly directed ruptured lobule. An intraluminal thrombus in the inferiorly directed lobule apparently obscured the lobule and caused the appearance of the basal dimple on the angiograms. In the second patient, a 40-year-old man who had been transferred to the author’s institution because of an angiographic evaluation that did not show any aneurysm despite SAH in the basal cisterns, initial angiography revealed a subtle dimple on the superior wall of the anterior communicating artery (ACoA). On follow-up angiography, a very small aneurysm was seen at the site of the dimple. A craniotomy then revealed a very small ruptured and thrombosed aneurysm on the superior wall of the ACoA.
Report of 2 cases
Jaechan Park and Dong-Hun Kang
Because infundibular widening most commonly appears at the origins of the posterior communicating artery and anterior choroidal artery from the internal carotid artery, its occurrence in association with the anterior communicating artery (ACoA) or the A1-A2 junction can be misinterpreted as an ACoA aneurysm on angiograms.
The authors report on 2 such cases; one in a 73-year-old woman with infundibular widening of the recurrent artery of Heubner, and the other in a 44-year-old woman with infundibular widening of a perforating vessel from the ACoA. The correct diagnosis was established based on surgical exploration. In addition, grayscale modification of 3D reconstruction images of preoperative digital subtraction angiography revealed the cases of the recurrent artery of Heubner and perforating artery of the ACoA arising from the apex of the infundibular widening.
Jaechan Park and Dakeun Lee
A spontaneous subarachnoid hemorrhage (SAH) from the middle cerebral artery is most commonly caused by the rupture of saccular aneurysms and rarely by fusiform aneurysms or arterial dissections/dissecting aneurysms. To the authors' knowledge, this is the first report of an intraarterial neoplasm causing an SAH. A 44-year-old woman presented with an SAH in the basal cisterns. Subsequent internal carotid artery angiography demonstrated a small bulge on the superior wall of the horizontal (M1) segment of the middle cerebral artery. However, a pterional craniotomy revealed a well-circumscribed solitary tumor with a diameter of 15 mm involving the superior wall of the M1 segment as the cause of the SAH. Pathological examination demonstrated typical findings of a schwannoma, elongated cells with tapered, spindle-shaped nuclei and indistinct cell borders, and diffuse immunoreactivity for the S100 protein.
Gregory J. Zipfel
Jaechan Park, Dong-Hun Kang and Bo-Young Chun
For oculomotor nerve palsy (ONP) induced by unruptured posterior communicating artery (PCoA) aneurysms, the authors performed surgical clipping via a superciliary keyhole approach as an optimal treatment modality with high efficiency and low invasiveness. In this study, they then evaluated the technical feasibility, safety, clinical outcomes, including recovery from ONP as well as cosmetic results, and durability of the procedure.
Thirteen patients presenting with complete (7 patients) or incomplete (6 patients) ONP underwent surgery via a superciliary approach. The operative video record was used to evaluate the technical feasibility, neurological examinations and CT were performed to analyze the safety of the treatment, and neuroophthalmological examinations and 3D CT angiography were undertaken to determine the effectiveness and durability of the treatment.
In all cases, the aneurysms were successfully clipped using a 3.5-cm eyebrow incision and supraorbital minicraniotomy. The mean operative time was 108 ± 24 minutes. Twelve (92.3%) of the 13 patients showed complete resolution of the ONP. All 6 patients (100%) with incomplete ONP recovered completely within 1–2 months after surgery, whereas 6 (85.7%) of the 7 patients with complete ONP recovered completely within 1–6 months after surgery. Cosmetic results for the operative wounds were excellent without frontalis palsy. The durability of the treatment was ascertained based on 3D CT angiograms obtained 1 year after surgery.
Surgical clipping via a superciliary keyhole approach can be an optimal treatment modality for PCoA aneurysms inducing ONP because it is effective, safe, and durable.
Jaechan Park, Jung Hyun Hwang and In Suk Hamm
✓ The authors report the first known case in which an anomalous collateral artery was found to connect the proximal A2 segment with the middle of the M1 segment. This rarity was associated with atresia of the T-shaped internal carotid artery bifurcation. Two aneurysms had developed on a tortuous and tangled portion of the anomalous artery; one of them had ruptured, producing a subarachnoid hemorrhage and an intracerebral hematoma in the area of the putamen. The aneurysms were clipped and the intracerebral hematoma was removed via an emergency craniotomy.
Possible causes of the anomaly and the differences between it and accessory and duplicated middle cerebral arteries are reviewed.
Jaechan Park and In-Suk Hamm
✓ Although many procedures have already been performed to mobilize and reconstruct the temporal muscle for pterional craniotomies, the authors described a novel cortical osteotomy technique for creating and mobilizing a cortical bone slat along the superior temporal line with the temporal muscle attached to it. Screw fixation of the cortical bone slat then provides secured temporal muscle reconstruction. As such, this new technique minimized damage to the temporal muscle and prevented the formation of an anterior temporal hollow. In addition, key hole and parietal burr hole defects were covered by the cortical bone slat.
Jaechan Park, Wonsoo Son, Youngseok Kwak and Boram Ohk
The objective of this study was to evaluate and compare the level of patient satisfaction and approach-related patient complaints between a superciliary keyhole approach and a pterional approach.
Patients who underwent an ipsilateral superciliary keyhole approach and a contralateral pterional approach for bilateral intracranial aneurysms during an 11-year period were contacted and asked to complete a patient satisfaction questionnaire. The questionnaire covered 5 complaint areas related to the surgical approaches: craniotomy-related pain, sensory symptoms in the head, cosmetic complaints, palpable cranial irregularities, and limited mouth opening. The patients were asked to rate the 5 complaint areas on a scale from 0 (asymptomatic or very pleasant) to 4 (severely symptomatic or very unpleasant). Finally, the patients were asked to rate the level of overall satisfaction related to each surgical procedure on a visual analog scale (VAS) from 0 (most unsatisfactory) to 100 (most satisfactory).
A total of 21 patients completed the patient satisfaction questionnaire during a follow-up clinic visit. For the superciliary procedures, no craniotomy-related pain, palpable irregularities, or limited mouth opening was reported, and only minor sensory symptoms (numbness in the forehead) and cosmetic complaints (short linear operative scar) were reported (score = 1) by 1 (4.8%) and 3 patients (14.3%), respectively. Compared with the pterional approach, the superciliary approach showed better outcomes regarding the incidence of craniotomy-related pain, cosmetic complaints, and palpable irregularities, with a significant between-approach difference (p < 0.05). Furthermore, the VAS score for patient satisfaction was significantly higher for the superciliary approach (mean 95.2 ± 6.0 [SD], range 80–100) than for the pterional approach (mean 71.4 ± 10.6, range 50–90). Moreover, for the pterional approach, a multiple linear regression analysis indicated that the crucial factors decreasing the level of patient satisfaction were cosmetic complaints, craniotomy-related pain, and sensory symptoms, in order of importance (p < 0.05).
In successful cases in which the primary surgical goal of complete aneurysm clipping without postoperative complications is achieved, a superciliary keyhole approach provides a much higher level of patient satisfaction than a pterional approach, despite a facial wound. For a pterional approach, the patient satisfaction level is affected by the cosmetic results, craniotomy-related pain, and numbness behind the hairline, in order of importance.
Jaechan Park, Wonsoo Son, Ki-Su Park, Dong-Hun Kang and Im Hee Shin
This study was an investigation of surgical cases of a ruptured middle cerebral artery (MCA) aneurysm that was conducted to identify the risk factors of an intraoperative premature rupture.
Among 927 patients with a ruptured intracranial aneurysm who were treated over an 8-year period, the medical records of 182 consecutive patients with a ruptured MCA aneurysm were examined for cases of a premature rupture, and the risk factors were then investigated. The risk factors considered for an intraoperative premature rupture of an MCA aneurysm included the following: patient age; sex; World Federation of Neurosurgical Societies clinical grade; modified Fisher grade; presence of an intracerebral hemorrhage (ICH); location of the ICH (frontal or temporal); volume of the ICH; maximum diameter of the ruptured MCA aneurysm; length of the preaneurysmal M1 segment between the carotid bifurcation and the MCA aneurysm; and a sign of sphenoid ridge proximation. The sphenoid ridge proximation sign was defined as a spatial proximation < 4 mm between the sphenoid ridge and the rupture point of the MCA aneurysm, such as a daughter sac, irregularity, or dome of the aneurysm, based on the axial source images of the brain CT angiography sequences.
A total of 11 patients (6.0%) suffered a premature rupture of the MCA aneurysm during surgery. The premature rupture occurrences were classified according to the stage of the surgery, as follows: 1) craniotomy and dural opening (n = 1); 2) aspiration or removal of the ICH (n = 1); 3) retraction of the frontal lobe (n = 1); 4) dissection of the sphenoid segment of the sylvian fissure to access the proximal vessel (n = 4); and 5) perianeurysmal dissection (n = 4). The multivariate analysis with a binary logistic regression revealed that presence of a sphenoid ridge proximation sign (p < 0.001), presence of a frontal ICH associated with the ruptured MCA aneurysm (p = 0.019), and a short preaneurysmal M1 segment (p = 0.043) were all statistically significant risk factors for a premature rupture. Plus, a receiver operating characteristic curve analysis revealed that a preaneurysmal M1 segment length ≤ 13.3 mm was the best cutoff value for predicting the occurrence of a premature rupture (area under curve 0.747; sensitivity 63.64%; specificity 81.66%).
Patients exhibiting a sphenoid ridge proximation sign, the presence of a frontal ICH, and/or a short preaneurysmal M1 segment are at high risk for an intraoperative premature rupture of a MCA aneurysm. Such high-risk MCA aneurysms have a superficial location close to the arachnoid in the sphenoidal compartment of the sylvian fissure and have a rupture point directed anteriorly.