Medical Since Cross-linked Sodium Hyaluronate Gel Prevention Of Epidural Adhesion After Laminectomy Rabbit Experimental Research

Objective To investigate the safety of medical self-crosslinked sodium hyaluronic gel(HyaRegen/SPI) on the prevention of epidural adhesions after laminectomy by using corticalsomatosensory evoked potentials (CSEP) and motor scoring.Methods Twenty-four new Zealand white rabbits with lumbar laminectomy at L5wererandomly divided into four groups: group A as control group, in which only saline was used toflush the laminectomy area before wound closure, group B, C and D as treated groups, in whichthe exposed dura were covered with0.5,0.75and1.0ml of the medical self-crosslinked sodiumhyaluronic gel (HyaRegen/SPI) respectively before wound closure. The CSEP with latency wasmonitored and recorded after anesthesia, laminectomy and wound closure and at8weekspost-surgery. Motor scoring was also conducted at the time of pre-surgery and also1day and8weeks post-surgery.Results There were no significant difference in CSEP latency among groups afteranesthesia and laminectomy (P>0.05). The latency in group C and D (covered with0.75and1.0ml HyaRegen/SPI respectively) was significantly prolonged (P <0.05) after wound closure,while there was no prolongation in group A (control group) and B (covered with0.5mlHyaRegen/SPI)(P>0.05). However, the latency in all groups was all in the normal range (P>0.05) at8weeks post-surgery. The evaluation of motor scores revealed that all animals had anormal motor function before surgery and at1day and8weeks post-surgery, except a lowermotor score in group C and D on1thday post-surgery.Conclusion There is a dosage limitation in the application of agent on the prevention ofepidural adhesions after laminectomy. The application of medical self-crosslinked sodiumhyaluronic gel (HyaRegen/SPI)0.5ml do not affect the electrophysiological function of spineand motor function in this animal model. Objective To evaluate the effectiveness of two kinds of medical self-crosslinked sodiumhyaluronate gel (HyaRegen/SPI,HyaRegen/SPII) in preventing epidural adhesions afterlaminectomy by Micro-CT combined with epidurography, general observation, histologicalevaluation and analysis of hydroxyproline concentration. To explore the practicability ofobservation and evaluation for the epidural adhesions by using Micro-CT combined withepidurography.Methods Thirty-six new Zealand white rabbits with lumbar laminectomy at L5wererandomly assigned into three groups: group A was served as control with only saline being usedto flush the laminectomy area before wound closure, while group B and C were served as treatedgroup with the exposed dura mater being covered with0.5ml HyaRegen/SPI or0.5mlHyaRegen/SPII respectively before wound closure. The CSEP with latency was monitored andrecorded after anesthesia, laminectomy and wound closure. All animals were euthanized atpost-surgery8weeks, and the spinal section (L4-L6) was removed and evaluated as follows:1.After the epidurography, each animal’s spinal section was underwent the scanning of Micro-CT,to observe the two-dimensional images and the images of three-dimensional reconstruction, andto measure the volume ratio(the filling volume of contrast agent/the unit volume of operationarea).(In order to make a better assessment about this indicator, we add6normal animals’ spinalsections that didn’t undergo lumbar laminectomy to make a comparison),2.the epidural adhesiondegree by macroscopic observation according to the Rydell standard,3.the histologicalobservation and evaluation of the specimen, and4.the hydroxyproline concentration analysis ofscar tissue in the backside of the dura mater.Results There were no significant difference in CSEP latency among groups afteranesthesia, laminectomy and wound closure (P>0.05). The scanning of Micro-CT combinedwith epidurography and the images of three-dimensional reconstruction showed that the contrastagent could fill the epidural space smoothly in the normal group (didn’t undergo lumbarlaminectomy), group B and C, except group A(Many filling defects have been observed). Themeasurements of volume ratio (the filling volume of contrast agent/the unit volume of operationarea) implied that there was no significant difference between the normal group, group B andC(P＞0.05),but there was a significant difference when each of them compared with group Awhich has a lower volume ratio(P＜0.05). The macroscopic evaluation revealed serious epiduraladhesions in group A that was hard to dissect and excise while almost no adhesion in group B and C, and the adhesion degree in both groups was significant lower than that in group A (P＜0.05). The histological observations revealed that there was new bone formation in the operativearea in each group of animals: in group A under the new bone extensive and tenacious epiduralscar adhesion was formed and the spinal cord was pulled to dorsal side that caused thedisappearance of epidural space, while in group B and C there was little epidural scar adhesionunder the new bone, the dura mater was clean without any evident adhesion to the surroundingtissue and epidural space can be seen clearly. The histological grades of epidural adhesionshowed that there were no significant difference between group B and C (P＞0.05), but therewere both significant lower than that in group A (P＜0.05). The analysis of hydroxyprolineconcentration showed that hydroxyproline concentration in epidural scar tissue in group B orgroup C was both signifcantly reduced when compared to groupA(P＜0.05).Conclusion Both two kinds of medical self-crosslinked sodium hyaluronate gel(HyaRegen/SPI and HyaRegen/SPII) could effectively prevent the epidural adhesions afterlaminectomy in New Zealand white rabbit model in8weeks.