Massive pneumocephalus as a risk factor for recurrence after chronic subdural hematoma surgery: A systematic review and meta-analysis

Background

Symptomatic chronic subdural hematoma (CSDH) is a prevalent neurosurgical condition predominantly managed through burr hole drainage. Postoperatively, pneumocephalus frequently manifests in CSDH cases, and in some instances, tension pneumocephalus may evolve into a life-threatening complication. Despite several studies examining the association between pneumocephalus and recurrence, the outcomes have remained inconclusive.

Methods

An extensive literature review was carried out utilizing PubMed, EmBase, Web of Science (including Medline), and the Cochrane Library for literature available until September 2024. Studies concerning the association between pneumocephalus and recurrence were identified. Utilizing the PRISMA guidelines, titles, abstracts, and full texts of the selected studies were examined, with articles gradually excluded based on predefined criteria. Data extracted from these studies were processed through RevMan 5.4 software. The primary outcome assessed was hematoma recurrence, while secondary outcomes involved prognosis and mortality rate.

Results

The analysis incorporated nineteen investigations, involving an aggregate of 3,202 individuals with confirmed CSDH diagnoses. The findings indicated that the recurrence rate (RR) in the pneumocephalus group was markedly higher in comparison to the control group (OR, 3.22; 95 % CI, 2.47–4.20, P < 0.00001). The subgroup with extensive pneumocephalus presented a notably higher RR compared to the no/minimal pneumocephalus subgroup (P < 0.00001). Furthermore, the massive pneumocephalus subgroup exhibited a higher RR when contrasted with the no/minimal/moderate pneumocephalus group (P < 0.00001). In addition, the massive pneumocephalus subgroup demonstrated a higher RR compared to the moderate pneumocephalus subgroup (P = 0.003). Nevertheless, no statistically significant variation in RR was identified between the moderate pneumocephalus and no/minimal pneumocephalus groups (P = 0.34). The analysis also demonstrated that outcomes in the pneumocephalus group were poorer when compared with the control group (OR, 0.18; 95 % CI, 0.09–0.35, P < 0.00001). Conversely, no statistically significant difference in mortality rates between the pneumocephalus and control groups (P = 0.67).

Conclusions

The recurrence of CSDH is linked to the volume of postoperative pneumocephalus. While small or moderate volumes of pneumocephalus do not influence the RR of CSDH, extensive pneumocephalus is considered a marked risk factor for postoperative recurrence in individuals with CSDH. Although pneumocephalus does not appear to affect mortality rates, it has a notable impact on the prognosis of CSDH. These conclusions necessitate further confirmation through large-scale, meticulously designed prospective studies.