Technical Note: Inlay-Onlay Sandwich Graft Technique for Repairing Durotomy in Spine Surgery for Fragile Dura

Incidental durotomy and cerebrospinal fluid leak in spine surgery is a common, well described complication encountered in spine surgery that can have good outcomes with prompt recognition and appropriate repair or management. Additional levels of technical challenge arise when the dura is very thin and fails to hold suture lines in primary repair. We present three lumbar-spine cases with dural opening, intended or unintended, in the setting of thin native dura providing poor suture substrate. In each case, inlay-onlay sandwich graft technique was used to achieve a successful lasting dural closure. Two of these cases initially involved delayed failure of primary suture repair or standard basic dural draft. Re-exploration in these two cases revealed widened suture defects due to fragile native dura, resulting in delayed post-operative CSF leak. We also report a case of inlay-onlay sandwich patch graft for initial dural closure in adult tethered cord release in the setting of thin native dura, in which simple primary closure was not feasible. We illustrate this inlayonlay graft operative technique, which can potentially be used for repairing dural openings involving thin native dura without intrinsic tissue strength to support primary suture repair. We envision that this technique can also be further extrapolated or adapted to other regions of dural repair as needed.