Local host response of commercially available dural patches for fetal repair of spina bifida aperta in rabbit model. (29th January 2023) - Kunpalin, Yada
Abstract: Objective: Fetal surgery for spina bifida aperta (SBA) by open hysterotomy typically repairs anatomical native tissue in layers. Increasingly, fetoscopic repair is performed using a dural patch followed by skin closure. We studied the host response to selected commercially available patches currently being used in a fetal rabbit model for spina bifida repair. Methods: SBA was surgically induced at 23–24 days of gestation (term = 31 days). Fetal rabbits were assigned to unrepaired (SBA group), or immediate repair with Duragen™ or Durepair™. Non‐operated littermates served as normal controls. At term, spinal cords underwent immunohistochemical staining including Nissl and glial fibrillary acidic protein. We hypothesized that spinal cord coverage with a dural patch and skin closure would preserve motor neuron density within the non‐inferiority limit of 201.65 cells/mm 2 and reduce inflammation compared to unrepaired SBA fetuses. Results: Motor neuron density assessed by Nissl staining was conserved both by Duragen ( n = 6, 89.5; 95% CI −158.3 to −20.6) and Durepair ( n = 6, 37.0; 95% CI −132.6 to −58.5), whereas density of GFAP‐positive cells to quantify inflammation was lower than in unrepaired SBA‐fetuses (SBA 2366.0 ± 669.7 cells/mm 2 vs. Duragen 1274.0 ± 157.2 cells/mm 2 ; p = 0.0002, Durepair 1069.0 ± 270.7 cells/mm 2 ; p < 0.0001). Conclusions: Covering the rabbit spinal cord with either Duragen or Durepair followed by skin closure preserves motor neuron density and reduces the inflammatory response. Key points: What is known? Fetal spina bifida repair improves outcome as compared to postnatal repair. The standard clinical neurosurgical technique is a layered watertight closure using native tissues. Most fetoscopic techniques use a commercially available dural patch to cover the spinal cord, but the experimental basis for this is limited. What is new? In the fetal spina bifida rabbit model, two‐layer repair using commercially available dural patch and skin closure conserves motor neuron density and reduces inflammation in the fetal spinal cord.