Injection Of Fibrin Sealant Directly Into Vertebral Body For Hemostasis Of Injured Cancellous Bone: An Experimental Study

BackgroundThe problems linked to blood loss and in spine surgery have been less studied than in other fields of orthopedics,such as joint-replacement procedures.In the field of spine surgery,blood loss comes mainly from three parts:soft tissue,vertebral venous plexus and injured cancellous bone.During the procedures of vertebrectomy and osteotomy,injured cancellous bone of vertebral body cause excess blood loss because of its anatomic properties.Widely exposed bony surfaces are not amenable to standard hemostatic maneuvers utilized during soft tissue surgery such as ligation,sutures,compression or cautery.So injured cancellous bone play an important role in the blood loss of these procedures.Cho KJ et al showed that the mean blood loss during PSO reached 2617±1645ml.Topical hemostatic agents have been proved effective in haemostasis in injured cancellous bone,but in the traditional administration topical hemostatic agents are usually used directly on the surface of injured cancellous bone.During the procedures of vertebrectomy and osteotomy,the exposure of injured cancellous bone is repetitive.So the feasibility of traditional administration is constrainted greatly and the hemostatic efficacy decrease obviously.Therefor,exploring a new administration of topical hemostatic agents,by which injured cancellous bone of vertebral body can obtains haemostasis before the exposure of injured cancellous bone is very necessary.Fibrin sealant generally contain two major components,fibrinogen(with or without factorⅩⅢ) and thrombin(plus calcium with or without antibrinolytic drugs). Fibrin sealants mimic the final phase of the coagulation cascade through the activation of fibrinogen by thrombin which,via a series of complex reactions,leads to the formation of a semirigid clot.Because of it's hemostatic,antiadhesion,sealing and healing properties,fibrin sealant has been used expand across a range of surgical settings.In the field of spine surgery,fibrin sealant has been use for fixation of graft bone,CT-guided percutaneous therapy of postoperation or Spontaneous CSF leaks and therapy of meningeal cysts of the sacral spine.Nonsuture dural repair using polyglycolic acid mesh and fibrin sealant was reported too.In haemostasis aspect, fibrin sealant has been used to reduce blood loss during Cotrel-Dubousset instrumentation for idiopathic scoliosis in the epidural space and to stop venous bleeding vertebral venous plexus.But fibrin sealant is used to block bone trabecula lacouna and blood sinus in vertebral body to obtain haemostasis in injured cancellous bone has not been reported.We select fibrin sealant as experimental material and expecte injured cancellous bone obtains haemostasis through injection of fibrin sealant directly into vertebral body.The mechanisms is that through block of bone trabecula lacouna and blood sinus in vertebral body haemostasis is obtained in injured cancellous bone.Our objective in this experiment is to evaluate the hemostatic efficacy and safety of injection of fibrin sealant directly into vertebral body and provide related evidence for clinical use.Objective:1) To evaluate the hemostatic efficacy of injection of fibrin sealant directly into vertebral body and explore a new way for haemostasis in injured cancellous bone of vertebral body;2) To observe the distribution of fibrin sealant in vertebral body and evaluate the feasibility of injection of fibrin sealant directly into vertebral body;3) To evaluate the safety of injection of fibrin sealant directly into vertebral body and provide related evidence for clinical use.Methods:1) hemostatic efficacyLumbar2-5 vertebral body of 6 dogs were exposed through anterior approach under intravenous anesthesia.L2-3 and L4-5 were subjected to paired design respectively and the 2 vertebral bodies were randomized to assign to either experimental or control group.In experimental group,fibrin sealant(2.Sml) was injected directly into vertebral bodies,control group was blank control.One bone defect of 8mm in diameter and 6mm in depth was created through the 2 vertebral bodies at the same time after fibrin sealant was injected.Time to controlled bleeding, time to hemostasis,hemorrhagic volume and percentage of hemostasis in 10min were recorded.2) Observation of distribution volume for FS in the vertebral bodyLumbar2-5 vertebral body of 6 dogs were exposed through anterior approach under intravenous anesthesia.FS mixed with lohexol according to the tatio of 5ml:1ml was injected into the 16 vertebral bodies.The dose was 2.5ml and the administration is the same as above.CT scan was performed 30min after administration.In transverse CT image by use of the soft ware calculating square of irregular figure the square of fibrin sealant and the vertebral body were obtained respectively.The volume of slices were obtained by the equation Vi=Si xhi.The volume of fibrin sealant and vertebral body were measured by both modalities of integration and radial line(V=V1 +V2 +V3 +…+Vn=∑Vi).Then the percentage of distribution volume for fibrin sealant in the vertebral body was calculated.3) The safety of injection of fibrin sealant directly into vertebral bodyInvestigate the disorders of blood clotting functions,pulmonary infarction and nerve compression symptoms caused by fibrin sealant leaks.The blood clotting functions were examined before and after experiment,CT scan were performed to assess fibrin sealant leakage.The movements of extremities of dogs were observed after experiment.X-ray chest film was obtained and the 10 dogs were execused to explore pulmonary infarction at the third day after experiment. Independent-Samples T test was used to compare time to controlled bleeding, time to hemostasis,and hemorrhagic volume.Fisher's Exact test was used to compare the percentages,so as to distinguish whether statistically significant difference exists or not.Statistical significance only exists when P <0.05.Results:1)hemostatic efficacyExperimental group and control group had the average time to controll bleeding for(97.50±48.20) versus(417.83±101.18) second(t=9.901,P<0.001),the time to hemostasis for(291.084±167.18) versus(890.83±237.32)second(t=7.157, P<0.001),the hemorrhagic volume for(0.80±0.67) versus(4.39±1.84)g(t=6.338, P<0.001).Hemostasis was achieved within 10 minutes in 11 bodies(91.67%) in experimental group and in 3 bodies in control group(16.67%)(P=0.001).2)Observation of distribution volume for fibrin sealant in the vertebral bodyThe average percentage of distribution volume for FS in the vertebral body was 72.11±11.19%.The minimum is 47.80%and the maximum is 87.60%.3) The safety of injection of fibrin sealant directly into vertebral bodyThere was no significant difference in PT between pre- and post-experiment (20.00%vs 40.00%,P=0.628).Fibrin sealant leakages were found in 6(16) bodies (37.50%),including 5 slight epidural leaks,lsight foramina leak,Fibrin sealant entering vein was not found and no major neurological complication was found. Pulmonary infarction was not found in autopsy.Conclusion:1)Injection of fibrin sealant directly into vertebral body offered effective hemostasis on injured cancellous bone;2) Distribution for fibrin sealant in the vertebral body is excellent;3) Injection of fibrin sealant directly into vertebral body is safe.