Incidence and Risk Factors for Skull Implant Displacement After Cranial Surgery

OBJECTIVE: Various complications that can occur during and after cranial surgery have been investigated extensively. One of the less frequent complications has thus far received little attention, however: displacement of the skull implant after craniotomy or craniectomy. The purpose of this study is to identify prognostic factors for the development of skull implant displacement (SID). METHODS: In this study, 9087 cranial surgeries performed between 2002 and 2017 were retrospectively examined for the occurrence of SID. Because a first analysis of the investigated data revealed that a notable number of SIDs occurred after a cranioplasty (CP) performed after a decompressive craniectomy (DC), we focused our investigation on these cases. A total of 669 DCs and 329 subsequently performed CPs were analyzed. Several factors were analyzed unadjusted as possible factors influencing the risk for the development of SID. RESULTS: A total of 13 implant dislocations occurred after CP (3.95%). Fixation technique is the only factor that seems to have had a significant influence, specifically not using miniplates as the fixation technique, which was associated with a higher risk of SID (P = 0.043). However, if fixation techniques are distinguished in more detail, no significant advantage of the miniplates over titanium clamps can be proven (P = 0.123). None of the remaining observed factors showed a statistically provable impact in our data. CONCLUSIONS: A notable number of SIDs only occur after CPs that follow a DC. An advantage in successful placement was observed when fixation of the skull implant during cranioplasty was performed using miniplates.