Contributed equally
It is widely acknowledged that arteriosclerosis and calcification of the parent artery and aneurysm neck make it difficult to clip posterior communicating artery (PCoA) aneurysms. A total of 136 cases of PCoA aneurysms accompanied by arteriosclerosis and calcification were collected and treated with clipping in the present study. Of the 136 patients, 112 were females (82.4%) and 24 were males (17.6%), with ages ranging from 37 to 76 years (mean age, 60.2 years). Rupture of a PCoA aneurysm was identified in 132 cases (97.1%), and there were 4 cases of unruptured PCoA aneurysms (2.9%). According to the severity of arteriosclerosis and calcification, the aneurysms were divided into type I, II or III. The treatment of type I aneurysms achieved the best curative effect. It is difficult to temporarily occlude type II and III aneurysms during surgery, and temporary occlusion failed in almost 50% of cases. Types II and III were prone to intraoperative aneurysm ruptures. A significantly higher rate of intraoperative aneurysm rupture was seen in type III compared with type II cases. Type II and III cases were more likely to be treated using a fenestrated clip for aneurysm clipping compared with type I cases, and fenestrated clips were used significantly more frequently in type III cases compared with type II cases. Arteriosclerosis and calcification were likely to affect the prognosis of patients, particularly in cases with type III arteriosclerosis and calcification of the parent artery and aneurysm neck. Therefore, the stratification of the arteriosclerosis and calcification of the parent artery and aneurysm neck into types I–III can guide the intraoperative aneurysm clipping strategy, aid in choosing the correct clips, and inform predictions of the occurrence of rupture and hemorrhage, as well as the prognosis for aneurysms.
Although the endovascular treatment of intracranial aneurysms has become a popular technique of surgical clipping for 25 years, coil embolization still has its limitations. In particular, the recurrence is high in cases of wide-neck, large aneurysm (
A total of 136 patients with PCoA aneurysms associated with arteriosclerosis and calcification, who were admitted to the Department of Neurosurgery, the First Hospital of Jilin University from January 2013 to June 2016, were continuously collected in this study. Written informed consent was obtained from the study participants. The study was approved by the Ethics Committee of the First Hospital of Jilin University and was conducted in accordance with the Declaration of Helsinki.
Of the 136 patients, 112 were female (82.4%) and 24 were male (17.6%), with ages ranging from 37 to 76 years (mean age, 60.2 years). A ruptured PCoA aneurysm was identified in 132 cases (97.1%), and 4 patients with unruptured aneurysms (2.9%) suffered from oculomotor palsy paralysis. According to Hunt-Hess grades (a minor revision of the Hunt and Hess scale) (
Arteriosclerosis and calcification of the aneurysm neck and/or parent artery was identified in 136 cases of PCoA aneurysms, which was determined using operative microscopy (OPMI PENTERO 800; Zeiss GmbH, Jena, Germany). Yellow or white areas on the aneurysm neck or parent artery indicated the presence of arteriosclerosis and calcification. The parent artery and aneurysm neck were pressed during surgery. If the parent artery and aneurysm neck were hardened, they were judged to be affected by arteriosclerosis and calcification.
The parent artery and aneurysm neck were classified into three types according to the extent of arteriosclerosis and calcification: Type I, arteriosclerosis and calcification of the aneurysm neck; type II, arteriosclerosis and calcification of the parent artery; and type III, arteriosclerosis and calcification of the parent artery and aneurysm neck. Representative images of these classifications are presented in
Aneurysm size was calculated using mean values of its length and width with the following formula: (Maximal length + maximal width)/2. For each aneurysm several length and width measurements were taken to obtain the accurate value.
The surgery adopted a pterion or enlarged pterion approach to isolate the lateral fissure, carotid cistern and part of the post-chiasmatic exposure of the aneurysm body and neck. If the anterior clinoid process occluded the aneurysm, it was resected epidurally or intradurally. The parent artery was temporarily occluded before clipping the parent artery, and the aneurysm was clipped with straight, curved, bent, bayonet-shaped or fenestrated aneurysm clips according to the location, direction and aneurysm size. As many aneurysms as possible were clipped. If a rupture occurred during aneurysm clipping, hemorrhaging was stopped using multiple aneurysm clips if necessary. If the hemorrhage could not be stopped, multiple fenestrated clips were used for aneurysm clipping. Careful attention was paid intraoperatively to protect the PCoA. Typical cases of clipping treatments are presented in
All patients were administered routine treatment postoperatively. If there was serious subarachnoid hemorrhaging, lumbar cistern drainage of the cerebrospinal fluid was performed. If there was a serious vasospasm, expansion and improvement of microcirculation were performed via 3H treatment (hypervolemia, hemodilution, hypertension) as described previously (
SPSS 19.0 statistical software (IBM Corp., Armonk, NY, USA) was used for data processing. Chi-square tests were used to analyze count data, while t-tests and one-way analysis of variance with Tukeys post hoc test were used to analyze measurement data. Data are presented as the mean ± standard deviation and P<0.05 was considered to indicate a statistically significant difference.
According to the classification of arteriosclerosis and calcification, 3 types were used, among the 136 cases of PCoA aneurysms, 4 were type I (3.0%), 86 were type II (63.2%) and 46 were type III (33.8%).
The aneurysm diameters ranged from 1.7 to 11.8 mm (mean, 5.9±2.5 mm; type I mean, 6.2±3.5 mm; type II mean, 5.8±2.5 mm; type III mean, 6.0±2.4 mm;
The anterior clinoid process was resected epidurally or intradurally before aneurysm clipping to reveal the presence of the parent artery and aneurysm neck in 2 cases. Among the 136 cases, 131 cases involved single PCoA aneurysms (96.3%) and 5 cases involved multiple aneurysms in other locations (3.7%), which were clipped at the same time. An aneurysm clip was used in 114 cases (83.8%), and ≥2 aneurysm clips were used for occlusion in 22 cases (16.2%) of PCoA aneurysms.
An attempt to temporarily block the parent artery was always made in the process of aneurysm clipping. The temporary occlusion of the parent artery was successfully performed in the 4 type I cases, 41 of the 86 type II cases (47.7%) and 22 of the 46 type III cases (47.8%). No statistically significant difference was observed between type II and III in the success rate of temporary occlusion of the parent artery (P>0.05;
No intraoperative aneurysm ruptures were observed in the 4 cases of type I arteriosclerosis and calcification; among the 86 type II cases, intraoperative rupture occurred in 5 cases (5.8%), and among the 46 type III cases, intraoperative rupture occurred in 11 cases (23.9%). The incidence of intraoperative rupture was significantly higher in type III cases compared with cases (P<0.05;
Fenestrated clips were not used in the 4 type I cases during aneurysm clipping. Among the 86 type II cases, fenestrated clips were used in 11 cases (12.8%), and among the 46 type III cases, fenestrated clips were used in 13 cases (28.3%). The use of fenestrated aneurysm clips was significantly more common in type III cases compared with type II cases (P<0.05;
After aneurysm clipping, the 4 type I cases did not exhibit any complications. Among the 86 type II cases, 9 cases (10.5%) deteriorated postoperatively, as the Hunt-Hess grades increased, and among the 46 type III cases, 11 (23.9%) deteriorated postoperatively. A significantly higher proportion of patients deteriorated postoperatively among the type III cases compared with the type II cases (P<0.05;
CTA follow-up was performed at 3–6 months postoperatively. Among the 136 cases, 120 cases (88.2%) were followed up with CTA. The results indicated that the aneurysms were completely closed without recurrence. At 6–12 months, a telephone follow-up was performed for the majority of patients (132/136, 97.1%). The GOS scores were as follows: 126 patients (95.5%) achieved a score of 5; 4 patients (3%) achieved a score of 4; and 2 patients (1.5%) achieved a score of 3.
The present study collected data from 136 patients, 82.4% of whom were female, generating a female-to-male ratio of 4.7:1. However, the female-to-male incidence ratio of intracranial ruptured aneurysms was between 1:1 and 2:1. In a 2001 study in Japan by Osawa
Currently, two primary surgical treatments are used for intracranial aneurysms, namely, neurosurgical clipping and endovascular coiling (
It was identified that if the arteriosclerosis and calcification of affected PCoA aneurysms was more severe, there are increased risks associated with clipping surgeries, such as intraoperative rupture, incomplete clipping (
The success rate of temporary occlusion during aneurysm clipping was different among patients with different degrees of arteriosclerosis and calcification. For intracranial aneurysm clipping, the parent artery should be temporarily occluded before clipping to reduce the pressure caused by blood flow within the aneurysm, thereby reducing the risk of rupture and facilitating a more completely occluded aneurysm during aneurysm clipping surgery (
The rupture and hemorrhage occurring in the process of clipping PCoA aneurysms has notable consequences because PCoA aneurysms originate from the internal carotid artery just entering the skull and experience a high shear force (
There are many techniques for clipping PCoA aneurysms, with >100 types of intracranial aneurysm clips available (
For PCoA aneurysm clipping surgeries involving arteriosclerosis and calcification, the prognosis of patients is closely associated with the classification of arteriosclerosis and calcification (
Aside from the use of clips to treat patients with type II and III aneurysms, endovascular coiling embolization is known to be effective for treating patients with these types of aneurysms (
In conclusion, 136 cases of clipping surgeries for PCoA aneurysms accompanied by arteriosclerosis and calcification were described in the present study. It was identified that classification of the extent of arteriosclerosis and calcification of the parent artery and aneurysm neck into types I–III can guide the aneurysm clipping operation strategy, assist with choosing the clips and help in predicting the occurrence of rupture and hemorrhaging. It can also provide some insight into the prognosis for intraoperative aneurysms.
Classification of arteriosclerosis and calcification. (A) Type I, only the aneurysm neck exhibits arteriosclerosis and calcification in intraoperative view. (B) CTA reconstruction indicating the PCoA aneurysm (arrow). (C) Type II, only the parent artery (internal carotid artery) exhibits arteriosclerosis and calcification. (D) CTA reconstruction indicating the PCoA aneurysm (arrow). (E) Type III, both the parent artery and aneurysm neck exhibit arteriosclerosis and calcification. (F) CTA reconstruction indicating the PCoA aneurysm (arrow). CTA, CT angiography; PCoA aneurysm, posterior communicating artery aneurysm.
Images of aneurysm clipping procedures from the same patient in case 1. (A) CT scan indicating subarachnoid hemorrhage. (B) Preoperative CTA showing a left PCoA aneurysm. (C) Intraoperative imaging indicating obvious arteriosclerosis and calcification of the parent arteries. (D) Use of the first fenestrated clip to clip the PCoA aneurysm. (E) Use of the second straight clip to clip the PCoA aneurysm. (F) Postoperative CTA indicating complete clipping of aneurysm. CT, computed tomography; CTA, CT angiography; PCoA aneurysm, posterior communicating artery aneurysm.
Images of aneurysm clipping procedures from the same patient in case 2. (A) CT scan indicating subarachnoid hemorrhage. (B) Preoperative CTA indicating right PCoA aneurysm. (C) Preoperative digital subtraction angiography indicating PCoA aneurysm. (D) Intraoperative imaging indicating obvious arteriosclerosis and calcification of the parent arteries. (E) Use of a curved clip in aneurysm clipping. (F) Postoperative CTA indicating the complete clipping of aneurysm. CT, computed tomography; CTA, CT angiography; PCoA aneurysm, posterior communicating artery aneurysm.
Aneurysm diameters.
Parameter | Total | Type I | Type II | Type III |
---|---|---|---|---|
Number | 136 | 4 | 86 | 46 |
Diameter (mm) | 5.9±2.5 | 6.2±3.5 | 5.8±2.5 | 6.0±2.4 |
Statistical comparisons among groups.
Comparison | P-value |
---|---|
Type I vs. type II | 0.95 |
Type II vs. type III | 0.93 |
Type I vs. type III | 0.99 |
Groups were compared using one-way analysis of variance with Tukeys post hoc test.
Surgical results for patients with type II and III arteriosclerosis and calcification.
Type II | Type III | ||||
---|---|---|---|---|---|
Result | n | % | n | % | P-value |
Temporary occlusion | 41 | 47.7 | 22 | 47.8 | 0.987 |
Intraoperative rupture | 5 | 5.8 | 11 | 23.9 | 0.040 |
Use of fenestrated clip | 11 | 12.8 | 13 | 28.3 | 0.028 |
Postoperative aggravation | 9 | 10.5 | 11 | 23.9 | 0.040 |
Groups were compared using t-tests.