Experimental rabbit hemilaminotomy model in the evaluation of peridural fibrosis: a minimally invasive peridural fibrosis model.

The neuronal adhesions of newly synthesized scar tissue to dura mater after spinal peridural operations represent an unsolved problem in neurosurgical practice. This experimental study was planned to compare the success of a rabbit hemilaminotomy procedure with the total laminectomy model in the evaluation of peridural fibrosis in terms of proposing a lesser invasive peridural adhesion model. Fourteen New Zealand white rabbits were used in this experiment. Laminectomy was performed in one level, and hemilaminotomy was done in another level. Four weeks after operation the rabbits were sacrificed by perfusion with 10 % neutral buffered formalin solution. The lumbar spines were removed and immersed in 10 % neutral buffered formalin for approximately 24 hours. Then each specimen was decalcified in 5 % formic acid for approximately 3 weeks. Specimens were cut coronally for gross inspection. Two blocks of tissue were taken from each laminectomy site to be processed and embedded in paraffin. In seven (50 %) of the laminectomy sites of the rabbits, fibrous tissue penetrated the spinal canal through the laminectomy defect and produced neural compression (Grade III). Eight (57 %) hemilaminotomy sites were in Grade III fibrosis. There was no difference between laminectomy and hemilaminotomy in regard to the dural adhesions. In this experimental study, we modified the rabbit total laminectomy model by using a hemilaminotomy procedure in the study of peridural scar formation. The authors conclude that this procedure is more simple, reliable, and lesser invasive than the total laminectomy model.     

壳多糖膜预防椎板切除术后硬膜周围粘连的实验研究

目的　观察壳多糖膜预防椎板切除术后硬膜周围粘连的作用。方法　２４ 只成年新西兰白兔 Ｌ３ 、 Ｌ５ 水平切除椎板１ ．０ ｃｍ ×０ ．５ ｃｍ , Ｌ３ 硬膜外放置壳多糖膜（ Ａ 点） , Ｌ５ 作为空白对照（ Ｂ 点） 。分别于术后３ 、６ 、１２ 周进行大体形态、光镜观察。结果　 Ａ 点硬膜外粘连程度明显低于 Ｂ 点;光镜观察 Ａ 点粘连范围明显低于 Ｂ 点, Ａ 点硬膜外有空隙,未见明显异物、炎症反应, Ｂ 点硬膜外与瘢痕紧密粘连,瘢痕侵入椎管内,对硬膜有压迫。结论　壳多糖膜具有明显的预防硬膜周围粘连的作用。     

Influence of TachoComb in comparison to local hemostyptic agents on epidural fibrosis in a rat laminectomy model.

This animal experimental study was designed to examine the effects of TachoComb, a fixed combination of collagen with tissue adhesive, as an interposition membrane on the development of spinal epidural fibrosis in comparison to other hemostyptic materials. In 10 Wistar rats, four laminectomies were performed at lumbar and sacral vertebrae. Alternately, a piece of TachoComb, Spongostan, or Tabotamp was placed into each laminectomy site. One laminectomy site served as an empty control (n = 10). 8 weeks later, the animals were sacrificed, and the spinal column including surrounding muscle tissue was removed en bloc from each rat and fixed in formaldehyde. After decalcification and staining the specimens were graded by a neuropathologist in a blindfold test for severity of epidural fibrosis as "light-moderate" or "marked". Epidural scarring of variable density was seen in all laminectomy sites. Light epidural fibrosis, without any adhesion to dura, as only noted in cases after application of TachoComb (n = 4/10) and Spongostan (n = 1/10). All other slices showed marked epidural fibrosis with dura adherence regardless of the implanted material. Statistical analysis revealed significantly lower epidural fibrosis after application of TachoComb compared to all other groups (p < 0.05). In this series, TachoComb is more effective in reducing the epidural fibrosis than Spongostan, and Tabotamp. However, complete prevention of scar tissue formation was not achieved.     

几丁糖膜预防椎板切除术后硬膜周围粘连的实验研究

目的：观察几丁糖膜对预防椎板切除术后硬膜周围粘连的作用。方法：２４只成年新西兰白兔Ｌ３、Ｌ５水平切除椎板１０×０５ｃｍ,Ｌ３硬膜外放置几丁糖膜（Ａ点）,Ｌ５作为空白对照（Ｂ点）。分别于术后３周、６周、１２周进行大体形态、组织学观察。结果：Ａ点硬膜与瘢痕无明显粘连,硬膜外有空隙,未见明显异物、炎症反应;Ｂ点硬膜与瘢痕紧密粘连,瘢痕侵入椎管内,对硬膜有压迫。结论：几丁糖膜具有明显的预防硬膜周围粘连的作用。     

Novel biodegradable lamina for lamina repair and reconstruction

Background contextPosterior laminectomy is an effective spinal surgical procedure. The adhesion of postoperative scar tissue to surgically exposed dura and, occasionally, to nerve roots can cause failed back surgery syndrome. The establishment of a barrier between scar tissue and dura that is made of hard material may prevent scar adhesions.PurposeTo evaluate the efficacy of a novel biodegradable multi-amino acid copolymer/nanohydroxyapatite composite artificial lamina.MethodsA cervical laminectomy animal model in goats was used, and the animals were randomly divided into three groups. In the test group, cervical 4 was removed by laminectomy and the artificial lamina was inserted (n=12). In the control group, the incision was closed directly without implantation (n=9). The goats in the normal group did not undergo any procedure or treatment. Copolymer efficiency was tested by using X-ray, computed tomography scanning, magnetic resonance imaging, scanning electronic microscope, and histologic and biomechanical measurements 4, 12, and 24 weeks postoperation.ResultsNo shifting of the artificial lamina or dural adhesion pressure was observed. New cervical natural bone formed in the defect and the bony spinal canal was rebuilt. In the control group, fibrous scar tissue filled the defect and exerted pressure on the dura. No paralysis was observed, and gait was normal in all test and control goats.ConclusionsArtificial lamina can prevent the epidural adhesions surrounding the defect and promote effectively bone tissue repair and new bone formation.     

Experimental study of osteoplastic laminectomy in the lumbar spine of rabbits

Osteoplastic laminectomy has been used to treat lumbar canal stenosis and to prevent postoperative lumbar spinal instability by reconstructing the posterior element of the lumbar spine, which has been documented in many clinical studies. However, the biological sequence of repairing the posterior lumbar element, which is replaced at the time of surgery, has not yet been made clear. An in vivo rabbit study was designed to observe the biological sequence of repairing the replaced posterior element of the lumbar spine. Twenty-one adult rabbits underwent osteoplastic laminectomy at the L6. Animals were killed at 2, 4, 8, 12, 26, and 52 weeks after surgery. The samples of the L6 vertebra, which contained the replaced lamina and spinous process, were analyzed by radiography, computed tomography (CT), and a histological method. Overall, radiograms demonstrated clearly the union of interarticular osteotomized sites from 4 to 8 weeks. CT findings revealed that the union of interarticular osteotomized sites could be confirmed beginning at 12 weeks, and that postoperative narrowing of the lumbar spinal canal had not occurred in the rabbit model. The biological sequence of repairing the replaced lamina and spinous process was characterized by slowly progressive creeping substitution, with continuous remodeling.     

Evaluation of hyaluronic acid sheet for the prevention of postlaminectomy adhesions.

BACKGROUND CONTEXT: Various materials have been tested for their ability to maintain a barrier between muscles and epidural space in order to physically or chemically inhibit scar ingrowths. Hyaluronic acid (HA) solution and gel have been reported to be effective in preventing adhesions postlaminectomy; however, neither has been used clinically after spinal surgery. PURPOSE: To determine the efficacy of HA sheet for the prevention of postlaminectomy adhesions compared with that of HA gel or another sheet. STUDY DESIGN/SETTING: An animal model of lumbar laminectomy in rabbits was used to study postoperative scar tissue formation around the spinal cord. The histologic effects of HA sheet were compared with those of Gelfoam (GF) and further evaluated by an inflammation model using rhTNF-alpha. PATIENT SAMPLE: Rabbit. OUTCOME MEASURES: Histologic examination. METHODS: Five rabbits were killed at 2, 4, 8, and 24 weeks after laminectomy, respectively. Another 18 rabbits were examined in an environment of active inflammation experimentally induced by rhTNF-alpha to compare the effects of HA sheet with those of GF or HA gel. Histologic examination was performed to quantitatively assess invasive scar formation or inflammation postlaminectomy, and then, the histologic effects of HA sheet were compared with those of GF or HA gel. RESULTS: In the HA group, significantly, the area of subarachnoid space was larger, distance from the surface of dura to scar tissues was greater, the number of inflammatory cells in the scar tissues at the site of laminectomy was less, and enlargement of dura was suppressed. Using an inflammation model, we also demonstrated the efficacy of HA sheet treatment. CONCLUSIONS: In an experimental laminectomy model, HA sheet formed a solid interpositional membrane barrier and exhibited anti-inflammatory activity. Further investigations will be needed for HA sheet to be used clinically.     

Late laminectomy in traumatic paraplegia

Long-term observation in cases of spinal injury with sub-arachnoid block, treated by laminectomy and removal of compressing elements, shows worthwhile results in a good percentage. Twenty-seven cases of fractures of the spine at the dorsolumbar and lumbar levels with conus and cauda equina injury were treated by laminectomy and decompression from 6 to 12 weeks after the injury, and have been followed for periods of 3–27 years. Surgical intervention was offered only in those cases in which myelography demonstrated a subarachnoid block. Most of the cases were operated on at 6–12 weeks after the injury. Displaced laminae, thickened ligamentum flavum, and arachnoidal adhesions were the common causes of compression. In six cases there was also an arachnoid cyst. Long-term follow-up showed improvement in bladder function in 14 of 27 patients, and in motor function in 8 of 27. In dorsolumbar and lumbar injuries in which there is a subarachnoid block, decompressive laminectomy is a worthwhile procedure.     

The density of nociceptive SP- and CGRP-immunopositive nerve fibers in the dura mater lumbalis of rats is enhanced after laminectomy,even after application of autologous fat grafts

A considerable number of patients complain about pain after lumbar surgery. The spinal dura mater has been debated as a possible source of this pain. However, there is no information if laminectomy influences the nociceptive sensory innervation of the dura. Therefore, we quantitatively evaluated the density of SP- and CGRP-immunopositive nerve fibers in the dura mater lumbalis in an animal model of laminectomy. Twelve adult Lewis rats underwent laminectomy, in six of them the exposed dura was covered by an autologous fat graft. Further six animals without surgical treatment served as controls. Six weeks after surgery, the animals were perfused and the lumbar dura was processed immunohistochemically for the detection of CGRP- and SP-containing nerve fibers. In controls, the peptidergic nerve fibers were found predominantly in the ventral but rarely in the dorsal dura mater lumbalis. After laminectomy, the density of SP- and CGRP-immunopositive neurons significantly increased in ventral as well as in dorsal parts of the dura. Axonal spines could be observed in some cases at the site of laminectomy. The application of autologous fat grafts failed to inhibit the significant increase in the density of peptidergic afferents. Thus, we have provided the first evidence that laminectomies induce an increase in the density of putative nociceptive SP- and CGRP-immunopositive neurons in the lumbar dura mater ascribable to an axonal sprouting of fine nerve fibers. This effect was not prevented by using autologous fat grafts. It is conceivable that the neuronal outgrowth of nociceptive afferents is a cause of low back pain observed after lumbar surgery.     

Prophylaxis of the laminectomy membrane. An experimental study in dogs.

Sixty laminectomies were performed in dogs to investigate the prevention of the laminectomy membrane and its side effects. These operations were distributed in six groups of 10, one was a control group, and in the others the bone defect was protected with different materials (Oxicel, Silastic, Dacron, methyl methacrylate, and Kiel bone graft). After a survival of 2 months, suboccipital myelography was performed, immediately after which the animals were sacrificed and the operated spinal slice obtained. The different radiographic densities of the tissues of each slice were calculated and the diverse histological nature identified by hematoxylin and eosin, periodic acid Schiff, Masson's trichrome, and Gomori's reticulin strains. Only the acrylic plastic and the Kiel bone graft prevented expansion of the scar tissue inside the spinal canal and adhesions between the dura and the cicatrical overlying muscles. Therefore, the authors suggest that a solid barrier is necessary to effectively prevent the so-called "laminectomy membrane."     

The biomechanics of decompressive laminectomy

The biomechanical effect of laminectomy as a means of relieving compression of the spinal cord-meningeal complex by an anterior mass was studied in ten grossly normal human cadaver spines. The basic experimental set-up involved drilling a sagittal plane hole transversely across a vertebral body to provide direct access to the anterior aspect of the neural canal. After securing a probe and linearly variable differential transformer (LVDT) assembly at each site to be tested, the probe was gently pushed into the neural canal; contact force against the tip of the probe as well as the depth of probe penetration was measured and recorded. Laminectomy did not alter the resulting contact force/anterior penetration plots at the fifth cervical, seventh thoracic, 12th thoracic, or third lumbar vertebra. Using the probe/LVDT assembly to measure anterior dural displacement and a cantilever displacement device to measure posterior dural displacement after laminectomy at the 12th thoracic vertebra, the authors found that although the anterior dura underwent gross displacement as the probe was pushed into the neural canal, the posterior dura displaced to a minimal degree. The extent of the laminectomy was not a factor. The study did not demonstrate any possible mechanism by which laminectomy could reduce the pressure exerted on the dura and neural elements by an anterior mass in a spine with otherwise normal neural canal dimensions.     

Safety of recombinant human bone morphogenetic protein-2 after spinal laminectomy in the dog

STUDY DESIGN: This was a randomized, blinded trial of the safety of the application of recombinant human bone morphogenetic protein (rhBMP)-2 or autologous bone graft onto a laminectomy defect of the dog in the presence or absence of a dural membrane puncture. OBJECTIVE: To test the safety of rhBMP-2 in an application in which direct contact of the material with neural tissue occurs. SUMMARY OF BACKGROUND DATA: Application of rhBMP-2 in laboratory animals stimulates local bone formation to effect spinal fusion and healing of segmental bone defects. The use of rhBMP-2 as a bone graft substitute in spinal fusion would eliminate donor site morbidity and may augment the rate of successful fusion. Because rhBMP-2 may unintentionally come in contact with neural tissue, the consequences of such a safety issue must be addressed in an animal model before human trials. METHODS: Twenty skeletally mature beagles underwent spinal exposure followed by bilateral laminectomy at L5. In half of the dogs, a puncture wound was made to the dura with the expression of cerebrospinal fluid at the site of the puncture. In randomly selected animals, the exposed dural elements received either autologous bone graft with the bone removed from the laminectomy site or an implant of the rhBMP-2 device. The animals was observed for 12 weeks with periodic clinical examinations and monthly computed tomographic scans. RESULTS: There was no clinical, radiographic, or histologic evidence of neurologic abnormalities in these animals. The rhBMP-2 stimulated bone growth in the laminectomy defect and came into direct contact with the dural membrane. There was no evidence of abnormal mineralization within the thecal sac or in the spinal cord itself. CONCLUSIONS: The rhBMP-2 implant stimulated bone formation in the laminectomy site. Neither autologous bone, rhBMP-2, nor the dural puncture had deleterious consequences for the animals.     

纤维蛋白封闭剂预防硬膜外粘连的实验研究

目的探讨纤维蛋白封闭剂预防术后硬膜外粘连的中长期效果。方法成年健康犬10只。均行L2及L5全椎板切除术,制作椎板缺损模型。随机取5只犬,于L2缺损区喷涂纤维蛋白封闭剂,L5作为空白对照;于另5只犬的L5缺损区喷涂纤维蛋白封闭剂,L2作为空白对照。均在术后6个月处死,取出腰椎进行大体观察、组织学及MRI研究。结果对照组可见大量瘢痕组织增生,硬膜与后方瘢痕组织粘连紧密。纤维蛋白封闭剂组硬膜与瘢痕之间有间隙。无明显粘连。结论纤维蛋白封闭剂中长期防粘连效果是可靠的。     

7.0T micro-MRI评价局部应用丝裂霉素C和消旋聚乳酸膜抑制大鼠硬膜外粘连及瘢痕形成

目的应用7.0Tmicro-MR比较单独应用丝裂霉素C（MMC）、消旋聚乳酸（DL-PLA）膜以及二者联合应用（MMC＋DL-PLA膜）时抑制大鼠椎板切除术后硬膜外粘连的效果。方法将16只SD大鼠随机分为4组,每组4只,椎板切除术后于硬膜外给予不同局部处理：单纯MMC组局部应用MMC 0.67mg/ml;单纯DL-PLA膜组给予生理盐水和0.05mm厚DL-PLA膜;MMC＋DL-PLA膜组给予MMC 0.67mg/ml和0.05mm厚DL-PLA膜;对照组单纯应用生理盐水。术后4周处死大鼠,分别行7.0Tmicro-MR扫描及瘢痕组织面积测定,并于镜下观察硬脊膜与后方瘢痕组织粘连情况。结果单纯MMC组和单纯DL-PLA膜组硬膜外瘢痕组织较疏松,瘢痕面积小,与硬脊膜部分粘连。MMC＋DL-PLA膜组硬膜外瘢痕组织较疏松,瘢痕面积更小,与硬脊膜未形成明显粘连。对照组标本硬膜外瘢痕组织致密,瘢痕面积大,与硬脊膜形成紧密粘连。结论局部单独应用浓度为0.67mg/ml的MMC或0.05mm厚的DL-PLA膜均能减少硬膜外瘢痕组织增生,二者联合应用时效果更显著。     

川芎嗪与自体骨膜联合运用预防椎板切除术后硬膜外粘连的实验研究

目的 观察椎板切除术后用川芎嗪的同时在椎板缺损处植入自体骨膜预防硬膜外粘连的效果.方法 48只SD大鼠随机分成4组(n=12),均制作L2椎板损伤模型,A组硬膜外涂布生理盐水,B组硬膜外涂布川芎嗪,C组硬膜外覆盖自体骨膜,D组硬膜外涂布川芎嗪的同时加自体骨膜覆盖.术后12周对4组椎板切除部位进行大体观察,对粘连度、胶原含量、组织学评分及骨转化生长因子定量分析进行比较.结果 B、C、D组的改良RydellBalazs粘连韧度评分、胶原含量、改良Nussvuaum组织学评分均优于A组,差异有统计学意义(P<0.05),D组优于B、C组,差异均有统计学意义(P<0.05);TGF-β灰度值C组与D组高于A组与B组,差异均有统计学意义(P<0.05).结论 联合运用川芎嗪和自体骨膜能有效预防硬膜外瘢痕粘连和形成,比单独应用川芎嗪和(或)自体骨膜预防效果好.     

同种异体骨板覆盖预防椎板切除术后硬膜外粘连临床应用

目的探讨同种异体骨板覆盖在预防椎板切除术后硬膜外粘连方面的疗效。方法对58例腰椎间盘突出或腰椎管狭窄患者,行全椎板切除,“H”形同种异体冻干辐照骨板覆盖。观察临床症状及CT、MR I表现。结果术后随访6个月~2.5年,CT、MR I椎管扩大,骨板无倾斜、移位,脊髓无压迫,无排异反应;术后椎管内容物形态良好,骨板两侧已与相邻接触骨组织融合,密度相等。结论同种异体冻干辐照骨板具有良好的生物相容性、生物力学性能和诱导成骨作用,是一种良好的硬膜外覆盖材料,能有效阻止硬膜外粘连,防止椎管术后再狭窄,可用于节段性椎管覆盖成型术。     

Effect of polylactic acid glue in preventing epidural scar mdhesion after laminectomy in rabbits

Objective： To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits. Methods： Twenty-four Japanese white rabbits underwent laminectomy （including the attached ligaments） at Lz and Ls. After laminectomy at Ls, polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at Lz, nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intraceHular structure of fibroblasts. Results： The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group,which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group. Conclusions： Polylactic acid glue can effectively reduce epidural cicatrization and adhesion.     

Effect of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits

Objective: To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits. Methods: Twenty-four Japanese white rabbits underwent laminectomy (including the attached ligaments) at L2 and L5. After laminectomy at L5, polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L2, nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts. Results: The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group, which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group. Conclusions: Polylactic acid glue can effectively reduce epidural cicatrization and adhesion.     

Experimental study on pedicle fat grafts after laminectomy: comparison of pedicle fat and free fat grafts

Scar formation adherent to the dura and nerve roots causes recurrent symptoms following laminectomy. Free and pedicle fat grafts have been performed in low-back surgery as a preventive measure. An experimental study in rats was designed to compare pedicle fat grafts and free fat grafts after wide laminectomy, for efficacy in preventing scar formation and for effects on the spinal cord. The following results were obtained. 1) Dense scar formation over the dura and degeneration of the cord were seen at control laminectomy sites. 2) Free fat grafts, examined at 2 and 4 weeks postoperatively, showed death of portions of the graft, whereas pedicle fat grafts always demonstrated the presence of living fat. 3) At 4 months postoperatively, pedicle fat grafts were statistically superior to free fat grafts, which showed scarring over the dura and degeneration of the cord. In conclusion, pedicle fat grafts were more effective in preventing dural scar formation and protecting the cord than free fat grafts.     

几丁糖与人工骨联合应用预防椎板切除术后硬膜外粘连的实验研究

目的:观察椎板切除术后用几丁糖(CHT)的同时在椎板缺损处植入磷酸三钙人工骨(TCP)预防硬膜外瘢痕粘连的效果。方法:40只纯种日本大耳白兔随机分成A、B、C、D四组,制作L4椎板损伤模型。A组硬膜外涂布生理盐水,B组硬膜外涂布几丁糖,C组硬膜外覆盖人工骨,D组硬膜外涂布几丁糖的同时加人工骨覆盖。术后12周对椎板切除部位进行大体观察、组织学观察及生化检查,比较各组间瘢痕形成和粘连情况。结果:B、C、D组的改良Rydell-Balazs粘连韧度评分、胶原含量及改良Nussvaum组织学评分均优于A组(P<0.01),D组优于B组与C组(P<0.05),B组与C组无显著性差异(P>0.05)。结论:联合应用几丁糖和人工骨能有效预防硬膜外瘢痕粘连的形成,比单独应用几丁糖和人工骨预防效果好。