221. Efficacy of patch technique for dural tear repair

BACKGROUND CONTEXT Dural tear is one of the most common complications of lumbar spine surgery. Primary treatment of dural tear is suture closure with or without sealing products. However, dural tear is often difficult to repair due to the requirement of meticulous suture technique in the limited space. This is particular for minimum invasive spine surgery, despite its recent increasing popularity. As an alternative method, several clinical studies reported patch technique (patch material and glue without suture) and found it to be efficient. However, experimental study to verify the efficacy of patch technique is extremely limited, particularly for hydrogel sealant. PURPOSE The purpose of this study was to verify the efficacy of patch technique for dural tear repair using a spinal pressure simulator and bovine dura, and compare patch materials. STUDY DESIGN/SETTING Basic research. OUTCOME MEASURES The pressure threshold for leakage. METHODS There were three study groups; Group 1 (control group, n=4): hydrogel sealant only, Group 2 (n=8): collagen sheet patch & hydrogel sealant, Group 3 (n=8): mesh sheet patch & hydrogel sealant. A section of the bovine dura was placed over the 3D printed cylinder with two O-rings holding on each side. Saline infused with blue food dye was filled under the dura and amidline 4-mm durotomy was made using an aorta punch. Patch material (collagen or mesh sheet) was placed over the dural tear area and then hydrogel sealant was sprayed over the patch material. Once the hydrogel sealant became stable, the pressure in the system was increased every 10 mm Hg and monitored. When the leakage occurred, the pressure threshold was measured. RESULTS The mean pressure threshold for leakage was 32.5 ± 15.0 mmHg in Group 1, 66.3 ± 37.0 mmHg in Group 2, and 88.8 ± 27.5 mmHg in Group 3. The mean pressure threshold for leakage in Group 3 was signifcantly higher than that in Group 1 (p<0.05)(mesh sheet & hydrogel sealant vs hydrogel sealant only). There was no difference in the mean pressure threshold for leakage between Group 1 and Group 2, or Group 2 and Group 3. CONCLUSIONS Patch technique using mesh sheet & hydrogel sealant demonstrated significantly higher mean pressure threshold for leakage compared with hydrogel sealant only. However, there was no difference between patch technique using collagen sheet & hydrogel sealant and hydrogel sealant only. Patch technique using mesh sheet & hydrogel sealant without suture is possibly a reasonable option for dural tear repair in lumbar spine surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Dural tear is one of the most common complications of lumbar spine surgery. Primary treatment of dural tear is suture closure with or without sealing products. However, dural tear is often difficult to repair due to the requirement of meticulous suture technique in the limited space. This is particular for minimum invasive spine surgery, despite its recent increasing popularity. As an alternative method, several clinical studies reported patch technique (patch material and glue without suture) and found it to be efficient. However, experimental study to verify the efficacy of patch technique is extremely limited, particularly for hydrogel sealant. The purpose of this study was to verify the efficacy of patch technique for dural tear repair using a spinal pressure simulator and bovine dura, and compare patch materials. Basic research. The pressure threshold for leakage. There were three study groups; Group 1 (control group, n=4): hydrogel sealant only, Group 2 (n=8): collagen sheet patch & hydrogel sealant, Group 3 (n=8): mesh sheet patch & hydrogel sealant. A section of the bovine dura was placed over the 3D printed cylinder with two O-rings holding on each side. Saline infused with blue food dye was filled under the dura and amidline 4-mm durotomy was made using an aorta punch. Patch material (collagen or mesh sheet) was placed over the dural tear area and then hydrogel sealant was sprayed over the patch material. Once the hydrogel sealant became stable, the pressure in the system was increased every 10 mm Hg and monitored. When the leakage occurred, the pressure threshold was measured. The mean pressure threshold for leakage was 32.5 ± 15.0 mmHg in Group 1, 66.3 ± 37.0 mmHg in Group 2, and 88.8 ± 27.5 mmHg in Group 3. The mean pressure threshold for leakage in Group 3 was signifcantly higher than that in Group 1 (p<0.05)(mesh sheet & hydrogel sealant vs hydrogel sealant only). There was no difference in the mean pressure threshold for leakage between Group 1 and Group 2, or Group 2 and Group 3. Patch technique using mesh sheet & hydrogel sealant demonstrated significantly higher mean pressure threshold for leakage compared with hydrogel sealant only. However, there was no difference between patch technique using collagen sheet & hydrogel sealant and hydrogel sealant only. Patch technique using mesh sheet & hydrogel sealant without suture is possibly a reasonable option for dural tear repair in lumbar spine surgery.