Avoiding calvarial defects in a Harrison's class IV thermally injured skull

Harrison's class IV calvarial burns with greater than 75% exposure present a special problem in flame injury. This problem is compounded in small children and or those with a large total body surface area burn, thus limiting the possibility of local flaps and free tissue transfers for coverage and leaving only wound care and skin grafts as options for closure. The literature suggests trephination with a high speed drill until viable bone is reached, then autografting the subsequent granulation tissue. In the most severe cases when the calvarium is deeply thermally injured and drilling down to the level of the Dura does not yield any sign of viability; should the surgeon proceed with removal of the clearly compromised calvarium down to Dura or leave it in place?

At a pediatric burn center, we reviewed all Harrison's class IV flame burns to the head with more than 75% exposure of the calvarium for a 2.5-year period. Five cases fit our inclusion criteria.

All five patients had drilling of the calvarium to debride dead bone. Three of the children had drilling that reached viable bone and were treated with a combination of early grafting and allowing granulation tissue to form then grafting. Two of the patients had extreme flame burns to the head with large areas having no clinical evidence of viability down to the Dura. The photographic record and CT reconstructions of these two cases are presented. The figures show the progression of healing of the calvarium in each child. A persistent calvarial defect only in the area of complete removal of calvarium to Dura is seen in each child's record. The remaining areas demonstrate progressive wound closure with remodeling of the skull in long term follow-up.

In deep massive calvarial burns to the head it is difficult to achieve wound closure. Trepanation with subsequent grafting and expectant management while awaiting granulation tissue bed is the current recommended treatment for this clinical problem. The aggressiveness of surgical debridement of dead bone is largely based on clinical appearance of the tissue. In the cases presented here, complete removal of clinically non-viable burned calvarium resulted in calvarial defects that were avoided when some deep calvarium was left in place despite its poor clinical appearance. The clinical challenge of closing calvarial defects in the reconstructive phase of care should not be underestimated. Therefore, avoidance of a defect if possible by allowing some bone to remain during trephination is recommended.