Comparison of subcutaneous pocket with cryopreservation method for storing autologous bone flaps in developing surgical wound infection after Cranioplasty: A randomized clinical trial.

BACKGROUND: Following a decompressive craniectomy (DC), the harvested bone flap is stored for future cranioplasty. There are two different methods proposed for bone banking, namely subcutaneous pocketing (SP) in the abdominal wall and cryopreservation (CP) in a refrigerator. This study was designed to evaluate the risk of developing infection in each study group. METHODS: In this randomized clinical trial design, a total of 143 patients underwent a primary decompressive craniectomy. Thereafter, they were randomly allocated into two groups, as SP and CP, and they were then scheduled for a future cranioplasty. Next, 108 patients underwent cranioplasty using an autologous bone flap and then followed-up for 18 months. Some variables, including demographic data, indications for primary DC, rate of post-operative clinical infection, bacterial culture results, the interval between craniectomy and cranioplasty, post-operative hospitalization duration, new morbidities, mortality rate, bone flap resorption rate, and several possible associated risk factors, were also recorded. The obtained data were analyzed by an expert bio-statistician using proper bio-statistical methods. A P value < 0.05 was considered as statistically significant. RESULTS: Four patients in the cryopreservation group (n = 50) indicated post-operative bone flap infection (8%), which was statistically significant (P = 0.041). Accordingly, all of them were resulted as positive for Methicillin-Resistant-Staphylococcus aureus (MRSA). Using the subcutaneous pocket method, no post-operative infection was observed after cranioplasty. The overall postoperative infection rate was estimated as 4%. The mean of age in the post-operative infection group's participants was 50.25 years old, and in the non-infected, it was 34.93 years old, which was also significant (P = 0.048). Bone flap resorption (BFR) rate was found to be higher by the use of CP method in comparison to SP technique (p = 0.0001). Of note, no other risk factor was found attributable to a higher BFR rate (p-values > 0.05). CONCLUSIONS: Older age and cryopreservation method at higher storage temperature (-18C˚) may be associated with infection's development after performing cranioplasty. BFR is more prevalent in the use of CP method rather than SP preservation technique.