Background. Although the concepts of «complex aneurysm» and «technically complex aneurysm» are widely used at present, there is no generally accepted definition. Moreover, the criteria are often subjective. Depending on the parameters included, complex aneurysms comprise 5—9.7% of all patients with cerebral aneurysms [1, 2]. Complex aneurysms have higher risk of complications, whose accurate assessment is difficult. In case of unruptured aneurysms, analysis of this risk is of particular importance.
OBJECTIVE
To develop the microsurgical complexity index in the treatment of unruptured aneurysms for objective assessment of complexity of microsurgical treatment and prediction of complications.
MATERIAL AND METHODS
The study included 850 patients with a single unruptured aneurysm who underwent microsurgical treatment. Postoperative outcomes and incidence of various complications were analyzed depending on anatomical and morphological characteristics of aneurysm.
RESULTS
We developed the microsurgical complexity index for the treatment of unruptured aneurysms and appropriate web application (www.isam.rf). Patients with severe neurological disorders at discharge comprised 2.5%, and mortality rate was 0.47%. New neurological deficit after surgery occurred in 9.3% of cases. Moderate and severe in-hospital complications occurred in 8.6% of cases. Non-radical exclusion of aneurysm was observed in 4.1% of cases. In case of complexity index «0», the incidence of various complications was lower compared to the group as a whole by 1.8—5.7%, index «1» — by 0.1—2.7%, index «2». The incidence of in-hospital complications Clavien-Dindo grade III-V was lower by 0.3%. The incidence of functional status mRS score 4—6 did not differ from the group as a whole, and the incidence of other complications was higher by 0.9—3.6%. In case of complexity index «3», the incidence of all complications was higher by 0.6—12.8%, index «4» — by 10.8—22.6%, index «5—6» — by 3.9—22.7%.
CONCLUSION
Original index may be valuable for more objective assessment of the risks of microsurgical treatment of aneurysms depending on anatomical and morphological characteristics and stratification of aneurysms according to their complexity. Aneurysms with index ≥3 may be classified as a group of complex aneurysms.
