Titanium Mesh Implant Exposure Due To Pressure Gradient Fluctuation.
OBJECTIVE
Titanium mesh implants (TMIs) are used for various purposes in craniotomy. Although delayed implant exposure and thinning of the overlying skin are well-known complications, the mechanism has not yet been elucidated. We reviewed our cases and propose a mechanism for TMI exposure.


METHODS
From 2009 to 2018, we treated 14 patients with delayed titanium implant exposure after craniotomy. The exposed titanium implant was a TMI in 4 patients, a titanium mesh plate in 6 patients, and a titanium fixation plate with holes in 4 patients. We reviewed the preoperative computed tomography (CT) scans and operative findings.


RESULTS
The interval between craniotomy and implant exposure was 13 years (range, 5-27). Implant exposure occurred at the temporal region in 7 patients, frontal region in 6 patients, and parietal region in 1 patient. The skin ulcer size ranged from 0.25 to 10 cm2 (mean, 1.95). In the patients with TMI exposure, the dura was expanded, and no residual epidural space was identified on the CT scans; however, epidural dead space was revealed on the CT scan in the patients with titanium mesh plate or titanium fixation plate exposure.


CONCLUSIONS
We believe that the key factor resulting in delayed titanium mesh exposure is the pressure gradient between the atmosphere and the intracranial space. Fluctuation of this gradient exerts dynamic stress on the tissue in the mesh holes and the adjacent tissue, resulting in tissue damage and implant exposure.
['Yoshioka|Nobutaka|N|', 'Tominaga|Shinsuke|S|']
D000368:Aged D000369:Aged, 80 and over D020520:Brain Infarction D001932:Brain Neoplasms D002543:Cerebral Hemorrhage D003399:Craniotomy D005260:Female D020199:Hematoma, Subdural, Acute D006801:Humans D002538:Intracranial Arteriovenous Malformations D008297:Male D008875:Middle Aged D011300:Preoperative Care D011312:Pressure D019736:Prostheses and Implants D011475:Prosthesis Failure D013526:Surgical Mesh D014025:Titanium D014057:Tomography, X-Ray Computed
Implant exposure Pressure gradient Complication Mechanism Titanium mesh exposure Cranioplasty