"Separation of Craniopagus Twins: A 30-year Systematic Review of Surgical Outcomes"

Craniopagus twins, conjoined at the calvarium, are the rarest and most complex form among conjoined twins, comprising ~3.4% of all cases. Surgical separation presents a significant challenge due to shared venous structure, brain parenchyma, and brain tissue. Despite advancements in surgical techniques, factors associated with successful separations remain poorly understood.

A systematic literature review was conducted to identify all reported craniopagus separation cases from 1995 to 2025, using Ovid MEDLINE and Scopus. A supplemental search of news articles was additionally performed via Google News to capture any recent or unpublished cases. A total of 33 cases met the inclusion criteria. Extracted variables included sex, age of separation, anatomical classification (O'Connell, Winston, Stone-Goodrich), surgical staging, use of tissue expanders, and urgency of procedure. The primary outcome measure was successful separation defined as the survival of both twins through 30 days postoperatively. Associations were analyzed using Fisher's exact test (p<0.05).

Among the three anatomical classifications, only the Stone-Goodrich system showed a significant association with surgical outcome (p=0.006), with total vertical (TV) cases achieving the highest success rate (90%). Statistically significant associations with successful outcome were also observed for multi-stage surgery (p=0.037), use of tissue expanders (p=0.006), and non-emergent procedures (p=0.039).

Anatomical configuration, surgical staging, utilization of tissue expanders, and urgency of operation were significantly associated with craniopagus separation outcomes. These findings highlight the importance of procedural factors and surgical advancements that may improve the survival of twins during separation.