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Chapter 3
MATERIALS AND METHODS
Study design and patient population
In this retrospective case series, 276 consecutive patients were included after a decompressive craniectomy and cranioplasty with autologous bone in separate procedures, performed between January 2004 and December 2014 in two centers [Academic Medical Center (Amsterdam) (n=183) and Elisabeth-Tweesteden Hospital (Tilburg) (n=93)] in the Netherlands. Both centers used identical protocols and procedures that did not change during the study period. Twenty-two patients were excluded because of bilateral defects to conserve homogeneity of the patient group in this study (N=10), or due to lack of follow-up, transfer to a different hospital, which may or may not have been in the Netherlands (N=7), missing data (N=4) and one non-disease related death 21 days after cranioplasty. Thus, a total of 254 consecutive patients were analyzed in this study.
Ethical consideration
This observational study was conducted using the STrengthening the Reporting of OBservational studies in Epidemiology guidelines (STROBE guideline) 32,33. The study protocol was approved by the medical ethics review board of the AMC (protocol nr. W18_030 # 18.046).
Surgical procedure
After decompressive craniectomy, the removed autologous bone flap was rinsed with 0.9% NaCl, dried with sterile gauze, packed into three sterile transplantation bags, and stored in the local bone bank at -80oC. Cranioplasty was performed as soon as the patient was medically and neurologically stable, and the wound had fully healed and was free of clinical signs of infection. Thirty minutes before incision, prophylactic antibiotics of a first- generation sodium cephalosporin (Kefzol®, Eurocept) were administered. If possible, the scar of the decompressive craniectomy was reopened and the edges of the cranial defect were made visible and accessible. The autologous bone flap was, if necessary, remodeled by minor adjustments and fixed to the skull, with either sutures or plates and screws. If the temporal muscle was dissected, it was suspended to the inserted autologous bone flap with sutures. A subgaleal drain was inserted for some patients, at the surgeon’s discretion. The skin was closed in two layers and a bandage was applied. All patients underwent standard postoperative care: patients received standard paracetamol post-operative and, if necessary, stronger analgesics were administered. Antibiotics were prescribed postoperatively at the discretion of the surgeon. All patients were seen at least once after the cranioplasty.