Autologous bone flap cranioplasty
The bone flap that is removed at the time of craniectomy has been preserved for future implantation. This is generally not employed in contaminated cases (penetrating trauma, infection…).
Available evidence on the safety of cranioplasty materials is limited due to a large diversity in study conduct, patients included and outcomes reported. Autologous bone grafts appear to carry a higher failure risk. Future publications concerning cranioplasties will benefit by a standardized reporting of surgical procedures, outcomes and graft materials used 1).
During the cranioplasty procedure, autologous bone flaps are preferably used due to their advantages in storage, viability, cost, prevention of disease transmission.
Storage options
a) in a“pocket” created in the patient’s subcutaneous abdominal fat
It is a simple and cheep alternative to other techniques and is available to any institution that provides autoclaving sterilisation services. 2).
Inherent difficulties of bone storage and cranioplasty are neglected in the literature.
The timing of cranioplasty and method of bone flap storage are known risk factors of non-union and resorption of bone flaps
Silay et al. present a simple method of bone storage and autologous cranioplasty in a small child with severe head injury. The child underwent surgical treatment with decompressive craniectomy. A bone flap was transversally divided into two pieces and stored under the galea. Bone storage and reconstruction of the cranial vault with this surgical technique is a safe, easy and cost-effective choice excluding the surgical trauma to obtain a new subcutanous pocket for bone storage in pediatric decompressive craniectomy patients 3).
Autologous bone flap cryopreservation
Timing
Complications
Systematic Review and Meta-Analysis
Consensus regarding the selection of synthetic versus autologous flap reimplantation for cranioplasty after decompressive craniectomy has not been reached and the multiple factors considered for each patient make comparative analysis challenging.
A study examined the association between choice of material and related complications.
A systematic literature review and meta-analysis were performed using PubMed for articles reporting delayed cranioplasty after decompressive craniectomy using a cohort design comparing autologous bone and synthetic implants. Extracted data included implant material and incidence of infection, reoperations related to the implant, wound complications, and resorption.
One randomized controlled trial and 11 cohort studies were included for a total of 1586 implants (950 bone, 636 synthetic). Autologous implants had significantly more reoperations than did synthetic implants (n = 1586 implants; odds ratio [OR], 1.91; 95% confidence interval [CI], 1.40-2.61). Reoperations were most often because of resorption (54%, n = 159/295) followed by infection (41%, n = 121/295). The pooled incidence of resorption in autologous implants was 20% (n = 159/791). Among the other outcomes, there was no significant difference for infections (n = 1586; OR, 1.24; CI, 0.82-1.88) or wound complications (n = 678; OR, 0.56; CI, 0.22-1.45). For the trauma subpopulation, there was no significant difference in infection rate with either material (n = 197; OR, 1.89; CI; 0.59-6.09).
Autologous implants had significantly more reoperations primarily because if the intrinsic risk of resorption (level of evidence 3b) 4).