Incidence and risk factors for skull implant displacement following cranial surgery

Abstract 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 the present study is to identify prognostic factors for the development of skull implant displacement (SID). Methods In this study, 9,087 cranial surgeries performed between 2002 and 2017 were retrospectively examined for the occurrence of SID. Since a first analysis of the investigated data revealed that a notable number of SIDs occurred after a cranioplasty (CP) performed following a decompressive craniectomy (DC), we focused our investigation on these cases. 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 the 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 have shown a statistically provable impact in our data. Conclusions A notable number of SIDs only occur after cranioplasties that follow a decompressive craniotomy. An advantage in successful placement was observed when fixation of the skull implant during cranioplasty was performed using miniplates.