Algorithmic approach to overcome scalp deficiency in the setting of secondary cranial reconstruction

Background: Multidisciplinary approaches have shown improved outcomes in secondary cranial reconstruction, however, scalp deficiency remains a common obstacle for tension-free scalp closure during cranioplasty. Therefore, our objective was to create an algorithmic approach using a novel concept of "component separation" to help minimize potential complications. Methods: The authors tested the hypothesis of achieving greater scalp mobility by way of "component separation" in a half-scalp, bilateral cadaver study, and describe within 2 clinical examples. Pterional-sized (N = 2) and hemicraniectomy-sized (N = 2) scalp flaps were dissected on 2 cadaveric heads using an internal control for each scenario. All flaps (N = 4) were created with (experimental group) and without (control group) "retaining ligament release." Total amounts of scalp mobility were measured bilaterally and compared accordingly. Results: Scalp flap mobility was calculated from the sagittal midline using identical arcs of rotation. With zero tension, we observed an increased distance of movement equaling 1cm for the "experimental" pterional flap, compared with the contralateral "control." Similarly, we found an increase of additional 2 cm in scalp mobility for the "experimental" hemicraniectomy-sized flap. Conclusions: Tension free scalp closure is most critical for achieving improved outcomes in secondary cranial reconstruction. In this study, we show that a range of 1 to 2 additional centimeters may be gained through a component separation, which is of critical value during scalp closure following cranioplasty. Therefore, based on our high volume cranioplasty experience and cadaver study presented, we offer some new insight on methods to overcome scalp deficiency accompanying secondary cranial reconstruction.