The temporal sequence of periosteal attachment after elevation.

This study investigated the adherence of periosteum to bone after elevation to document the temporal sequence of healing at the periosteal/bone interface. There has been a lack of consensus among surgeons as to the time required for healing at this interface; some believe that the healing achieves significant strength in a few days, whereas others believe that the periosteum does not adhere to the bone for many weeks. The aim of this study was to document the time course for healing, completeness of the reattachment, and structural characteristics of the union of bone and periosteum. To test the hypothesis, scalp flaps were elevated in a subperiosteal plane and were reattached in 40 adult guinea pigs and controls. The individual groups were studied at 3, 6, 12, 30, and 90 days postoperatively. Postmortem study consisted of analysis of the mechanical and histologic findings. Strength of adherence was documented by measuring the force required for reverse avulsion of the flaps with an Instron Mini 44 tensiometer. The specimens were also submitted for electron microscopic examination. The mean tension recorded in the plateau phase of avulsion of the flaps was as follows: controls, 78 g; experimental at 3 and 6 days, not applicable (weak adherence not permitting exposure for reverse avulsion); 12 days, 39 g (p = 0.0001); 30 days, 58 g (p = 0.0012), and 90 days, 63 g (p = 0.0229). There was a significant difference between all groups and the controls. Electron microscopic study showed collagen deposition at the bone periosteal interface, which became progressively more organized in the groups studied at 30 and 90 days, with decreasing amounts of inflammation and inflammatory cells. This study demonstrated that healing at the bone/periosteal interface progresses at a rate consistent with healing of most other wounds, dispelling many widespread beliefs that the adherence at this interface was accelerated. The temporal sequence of healing at the periosteal bone interface should be considered in the various procedures in which periosteal flaps are elevated. For example, there is clinical relevance in subperiosteal brow lift procedures, in which the periosteum should be reattached by a fixation technique that will remain stable for a minimum of 30 days to allow adequate adherence between the bone and periosteum at the postoperative elevated brow position.