Objective To evaluate the biomechanical characteristicsof titanium mesh with anterior plate fixation or ilium autograft in anterior cervical decompression.Methods Six fresh cervical spine specimens(C3-7) of young cadaver were used in the biomechanical test. After C5, C5,6 and C4-6 were given vertebrectomy,ilium autograft and titanium mesh with anterior plate fixation were performed. Their stabilities of flexion,bilateral axial rotation,the lateral bending and the extension were tested. Intact cervical spine specimens served as control group. Results Ilium autograft improved the stability of the unstable cervical vertebrae and decreased the flexion, the lateral bending or the extension, showing a significant difference when compared with control group(Plt;0.05). Whereas, axial rotational motion was decreased insignificantly(Pgt;0.05). Titanium meshwith anterior plate fixation improved the stability of the unstable spine and decreased the flexion,the bilateral axial rotation,the lateral bending or the extension, showing a significant difference when compared with control group(Plt;0.05). Conclusion The vertebrectomy and anterior cervical fusion by ilium autograft was the least stable construct of all modes tested,and the titanium mesh implantation is stabler than the intact cervical sample.
Objective To compare the effectiveness of three different bone grafts [autogenous bone, allogeneic bone, and bone morphogenetic protein (BMP) composite bone] combined with screw system for spinal fusion of degenerative lumbardisease. Methods Between January 2005 and January 2010, 102 cases of degenerative lumbar disease were randomly treated with autogenous bone (group A, n=35), allogeneic bone (group B, n=33), and BMP composite bone (group C, n=34). There was no significant difference in sex, age, disease duration, affected segments, Meyerding grade, preoperative intervertebral space height, and the Japanese Orthopaedic Association (JOA) score among 3 groups (P gt; 0.05). The intervertebral space height, bone fusion rate, and JOA score were compared among 3 groups at different time points. Results All patients of 3 groups were followed up 2 to 5 years, with an average of 3.2 years. At 6 to 24 months after operation, the intervertebral space height significantly increased when compared with preoperative value in 3 groups (P lt; 0.05); the intervertebral space height of groups A and C was significantly greater than that of group B at 6, 12, 18, and 24 months after operation (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Bone graft fusion was observed at 6 months in groups A and C and at 12 months in group B; at 24 months, the rate of bone graft fusion was 100% in groups A and C, and 87.88% in group B, showing significant difference (P lt; 0.05). There was significant difference in JOA score between preoperation and postoperative 12th and 24th months (P lt; 0.05); at 12 and 24 months after operation, JOA socre and improving rate of groups A and C were significantly higher than those of group B (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Conclusion The effect of BMP composite bone is equivalent to that of autogenous bone graft in treating spinal fusion of degenerative lumbar disease, and they are better than allogeneic bone graft. BMP composite bone can obtain adequate bone grafts without invasive sampling, and has fast fusion and high successful rate.
Objective To evluate the clinical outcome of autograftsof ilium and interbody fusion cage or bone morphogenetic protein(BMP)／artificial bone material／ cage in treating lumbar spondylolisthesis. Methods From January 1997 to January 2004，114 patients with lumbar spondylolisthesis were treated with posterior lumbar interbody fusion and pedicle screw fixation． There were 45 males and 69 females with an average age of 43 years ranging from 32 to 61 years. Of 114patients, 85 cases were classified as degree Ⅰ, 24 cases as degree Ⅱ and 5 cases as degree Ⅲ. The patients were divided into three groups accordingto the material used for interbody fusion: autografts of ilium (group A, n=42), interbody fusion cages(group B, n=36), and BMP／artificial bone material／ cage (group C, n=36)．The clinical and radiographic results of the patients were compared among three groups． Results All patients were followed from 13 to 30 months with an average of 15 months． There were no statistically significant differences in surgical time, blood loss, and disc space height of preoperation(P＞0.05) among three groups. No severe complication occurred in the three groups(P＞0.05). The excellent and good rates in groups A，B and C were 81.0％, 80.6％, and 83.3％ respectively, showing no statisticallysignificant difference(P＞0.05)．The fusion rate of group C(97.0%) was significantly higher than those of group A(81.0%) and group B(83.3%) (P＜0.05) after 1 year of operation．And the average loss of disc space height in groups B and C was significantly lower than that in group A(P＜0.05). Conclusion Higher fusion rate and lower loss of disc space height can beobtained in treating lumbar spondylolisthesis with BMP／artificial bone materiel.It is an effective method in the treatment of spondylolisthesis.
Objective To investigate the stability and the stress distributions of L3-5 fused with three different approaches (interbody, posterolateral and circumferential fusions) and to investigate degeneration of thesegment adjacent to the fused functional spinal unit. Methods A detailed L3-5 three-dimensional nonlinear finite element model of a normal man aged 32 was established and validated. Based on the model, the destabilized model, the interbody, posterolateral and circumferential fusions models of L4-5 were established. After the loadings were placed on all the models, we recorded the angular motions of the fused segment and the Von Mises stress of the adjacent intervertebral disc. Results The circumferential fusion was most stable than the others, and the interbody fusion was more stable than the posterolateral fusion. The maximal Von Mises stress of the adjacent L3,4 intervertebral disc in all the models was ranked descendingly as flexion,lateral bending,torsion and extension. For the three kinds of fusions, the stress increment of the L3,4 intervertebral disc was ranked ascendingly as interbody fusion,posterolateral fusion and circumferential fusion. Conclusion After destabilization of the L4,5 segment, the stability of the circumferential fusionis better than that of the others, particularly under the flexional or extensional loading. The stability of the interbody fusion is better than that of the posterolateral fusion, except for under the flexional loading. The feasibility of adjacent segment degeneration can be ranked descendingly as: circumferential fusion,posterolateral fusion and interbody fusion.
Objective To study the properties of the xenogeneic deproteinized cancellous bone used as a scaffold in the bone tissue engineering andits application to the spinal fusion of the lumbar intertransverse process in agoat. Methods The deproteinized bone was derived from an adult pig’s femoral cancellous bone through the physical and chemical treatments. Its morphological features, constituting components, and biomechanical properties were examined by the scanning electron microscopy, X-ray diffraction analysis, and mechanical experimental instrument. The cell-material complex was observed under the inverted phase contrast microscope to evaluate the adhesion and the growth of the osteoblasts. The experimental model of the spinal fusion of the lumbar intertransverse process was produced in 12 male goats aged 6-8 months, which were divided into two groups. In Group A, the tissue engineered bone constructed by thexenogeneic deproteinized cancellous bone, the recombinant human bone morphogenetic protein 2, and the mesenchymal stem cells was used for the spinal fusion; however, in Group B the autoilium was used. The samples were harvested at 4, 8 and 12 weeks postoperatively, and a series of examinations were performed, including the radiography and the histomorphological assay. Results The deproteinized cancellous bone had a natural pore network system, with an aperture ranging in size from 200 to 500 μm, containing a main organic material ofcollagen and the inorganic material of hydroxyapatite. So, the deproteinized cancellous bone had a good mechanical strength and a good histocompatibility. In Group A, the X-ray examination at different timepoints postoperatively showed that at 4 weeks,the bridging areas of all the fusion sites were not clear, especially on the internal side; at 8 weeks, the upper and lower bridged parts had a narrowed gap, with formation of much continuous bony callus; at 12 weeks, a complete fusion occurred. In the early stage, the material density was slightly lowerin Group A than in Group B, but at 12 weeks the density was almost the same in both the groups. Histological examination in the transplant area showed that at 4 weeks in Group A there was a new bone formation in a multipoint way; at 8 weeks, a “sandwichshaped” new bone wascrossed with the transplanting materials; and at 12 weeks, a medullary cavity was remodeled and a new cancellous bone was formed. The osteogenic process of thetissue engineered bone constructed by the xenogeneic deproteinized cancellous bone scaffold was almost the same as the autoilium osteogenesis. Conclusion The xenogeneic deproteinized cancellous bone is a good material in the bone tissue engineering, which can be used as an osteogenesis scaffold andprovide a stable environment for revascularization and osteoblastic differentiation.
Objective To investigate the clinical effect of medical grade calcium sulfate(Osteoset) as a bone graft substitute. Methods From December 2004 to May 2005, 9 cases of bone defect(limb group)were repaired with Osteoset pellets; bone defect was caused by benign tumor inlimbs, including 3 cases of fibroma xanthomas in humerus(1 case) and acetabulum (2 cases), 2 cases of bone cysts in humerus(1) and radius(1), 1 case of nonossifying fibroma, 1 case of ossifying fibroma and 2 cases of osteofibrous dysplasia in femurs. Five cases of lumbar posterolateral fusion (spine group) were treated with Osteoset pellets as autograft volume expander, including 2 cases of lumbar spinal stenosis, 2 cases of lumbar spondylolisthesis and 1 case of lumbar spondylolysis. Radiological method was used to evaluate the repair effect of Osteoset pellets. Results The mean follow-up time was 6.2 months (3to 9 months). Osteoset pellets began to be absorbed after 1 to 3 months of operation, and were totally absorbed and replaced by osseous tissue after 4 to 6months. No local recurrence was detected in limb group and the function of limbs was normal. At 6 months after operation, all patients in spine group got bony fusion. Conclusion Medical grade calcium sulfate (Osteoset) isan ideal bone graft substitute with excellent bone repair effect.
Objective To analyze the cl inical features of scol iosis associated with Chiari I malformation in adolescent patients, and to explore the val idity and safety of one-stage posterior approach and vertebral column resection for the correction of severe scol iosis. Methods Between October 2004 and August 2008, 17 adolescent patients with scol iosis associated with Chiari I malformation were treated with surgical correction through posterior approach and pedicle instrumentation. There were 9 males and 8 females with an average age of 15.1 years (range, 12-19 years). The MRI scanning showed that 16 of 17 patients had syringomyel ia in cervical or thoracic spinal cord. Apex vertebra of scol iosis were located atT7-12. One-stage posterior vertebral column resection and instrumental correction were performed on 9 patients whose Cobb angle of scol iosis or kyphosis was more than 90°, or who was associated with apparent neurological deficits (total spondylectomy group). Other 8 patients underwent posterior instrumental correction alone (simple correction group). All patients’ fixation and fusion segment ranged from upper thoracic spine to lumbar spine. Results The operative time and the blood loss were (384 ± 65) minutes and (4 160 ± 336) mL in total spondylectomy group, and were (246 ± 47) minutes and (1 450 ± 213) mL in simple correction group; showing significant differences (P lt; 0.05). In total spondylectomy group, coagulation disorder occurred in 1 case, pleural perforation in 4 cases, and lung infection in 1 case. In simple correcction group, pleural perforation occurred in 1 case. These patients were improved after symptomatic treatment. All patients were followed up 24-36 months (32.5 months on average). Bony heal ing was achieved at 6-12 months in total spondylectomy group. No breakage or pull ingout of internal fixator occurred. The angles of kyphosis and scol iosis were significantly improved at 1 week after operation (P lt; 0.01) when compared with those before operation. The correction rates of scol iosis and kyphosis (63.4% ± 4.6% and 72.1% ± 5.8%) in total spondylectomy group were better than those (69.4% ± 17.6% and 48.8% ± 19.3%) in simple correction group. Conclusion Suboccipital decompression before spine deformity correction may not always be necessary in adolescent scol iosis patients associated with Chiari I malformation. In patients with severe and rigid curve or apparente neurological deficits, posterior vertebral column resection would provide the opportunity of satisfied deformity correction and decrease the risk of neurological injury connected with surgical correction.
Objective To explore the feasibilities, methods, outcomes and indications of atlas pedicle screw system fixation and fusion for the treatment of upper cervical diseases. Methods From October 2004 to January 2006, 17 patients with upper cervical diseases were treated with atlas pedicle screw system fixation and fusion. There were 13 males and 4 females, ageing 19 to 52 years. Of 17 cases, there were 14 cases of atlantoaxial dislocation(including 3 cases of congenital odontoid disconnection，4 cases of old odontoid fracture，2 cases of new odontoid fracture(typeⅡC), 3 cases of rupture of the transverse ligament, and 2 cases of atlas fracture； 2 cases of tumor of C2; 1case of giant neurilemoma of C2,3 with instability after the resection oftumors. JOA score before operation was 8.3±3.0. Results The mean operative time and bleeding amount were 2.7 hours (2.1-3.4 hours) and 490 ml (300-750 ml) respectively. No injuries to the vertebral artery and spinal cord were observed. The medial-superior cortex of lateral mass was penetrated by 1 C1 screw approximately 3 mmwithout affecting occipito-atlantal motions. All patients were followed up 3-18 months. The clinical symptoms were improved in some extents and the screws were verified to be in a proper position, no breakage or loosening of screw and rob occurred. All patients achieved a solid bone fusion after 3-6 months. JOA score 3 months after operation was14.6±2.2. JOA improvement rates were 73%-91%(mean 82%). Conclusion The atlas pedicle screw system fixation and fusion is feasible for the treatment of upper cervical diseases and has betteroutcomes, wider indications if conducted properly.
Objective To investigate the relationship between the volume of bone-graft and fusion efficacy in posterior lumbar interbody fusion and internal fixation of spondylolisthesis. Methods Between May 2004 and June 2007, 79 patients with spondylolisthesis were treated with posterior lumbar interbody fusion and internal fixation. The patients were randomly divided into 3 groups according to the volume of bone-graft for interbody fusion: group A (n=27), 5 bone granules/ cm3 on average; group B (n=26), 11 bone granules/cm3 on average; and group C (n=26), 25 bone granules/cm3 on average. There was no significant difference in gender, age, disease duration, affected segment, and the degree of vertebral slip among 3 groups (P gt; 0.05). The volume of bone-graft, the fusion rate, the loss of intervertebral height, and the incidence of internal fixation failure were compared among 3 groups. Results All cases were followed up 24-43 months (mean, 35 months). There were significant differences in volume of bone-graft among 3 groups (P lt; 0.05). There was no significant difference in total volume of bone-graft and Cage height among 3 groups (P gt; 0.05). The Oswestry disability index (ODI) and visual analogue scale (VAS) scores of low back pain and leg pain at last follow-up were significantly decreased when compared with preoperative scores in 3 groups (P lt; 0.05); but no significant difference was found among 3 groups (P gt; 0.05). The fusion rate was significantly higher in group B than in groups A and C, and in group A than in group C at 1 and 2 years after operation (P lt; 0.05). The change values of the intervertebral height were (2.2 ± 1.4), (0.8 ± 1.3), and (2.3 ± 1.6) mm respectively in groups A, B, and C; it was significantly lower in group B than in groups A and C (P lt; 0.05). The degree of vertebral slip at immediately after operation and last follow-up was significantly improved when compared with preoperative one in 3 groups (P lt; 0.05); the loss of vertebral slip in group B was significantly lower than that in groups A and C at last follow-up (P lt; 0.05). After operation, nail breaking occurred in 1 case (3.7%) of group C at 1 year, depinning in 1 case (3.8%) of group A at 2 years, and no nail breaking or depinning in group B. There was no significant difference in the incidence of internal fixation failure among 3 groups (χ2=3.950, P=0.604). Conclusion The application of bone-graft with middle volume (11 bone granules/cm3 on average) in internal fixation and posterior lumbar interbody fusion has a good imageology outcome, which can increase the fusion rate and decrease the loss of intervertebral height.
Objective To discuss the main points of technique and the range of fusion in posterior operation of spinal stenosis associated with lumbar degenerative kyphosis (LDK). Methods The cl inical data were retrospectively analysedfrom 20 cases of spinal stenosis associated with LDK which were performed posterior operation from February 2001 to February 2008. There were 1 male and 19 females, aged 52-81 years old with an average of 64 years old. The course of disease was 6-10 years. All patients had severe low back pain. According to Frankel’s neurologic function classification, there were 18 cases of grade E and 2 cases of grade D before operation. The apex of LDK included L1 in 3 cases, L2 in 10 and L3 in 7. The operational method was decided according to different characteristics of LDK. All patients were divided into three groups. Group 1 included 6 cases of sciatica and intermittent claudication with worse physical status, the segmental decompression of spinal canal, posterior intervertebral fusion and short transpedical instrument fixation were performed. Group 2 included 8 cases whose Cobb angle of LDK was less than 20°, the segmental decompression of spinal canal, posterior intervertebral fusion and one-level or multilevel lamina osteotomy were performed, instrumentation-assisted correction was used. Group 3 included 6 cases whose Cobb angle of LDK was more than 20°, the canal decompression and one-level transvertebral wedge osteotomy were performed, instrumentation-assisted correction, intervertebral fusion and posterior-lateral fusion were used. Results Incision healedby first intention in all patients. One patient suffered from superior mesenteric artery syndrome at 6 hours after operationand healed after symptomatic management. The neurologic function was improved to grade E at 2 weeks after opeartion. All patients were followed-up 24-54 months (average 26 months). At last follow-up，the Oswestry Disabil ity Index of all patients was 30.5% ± 9.6%; showing significant difference when compared with preoperation (55.9% ± 11.8%, P lt; 0.05). The back pain scoring and leg pain scoring were 2.8 ± 1.6 and 2.4 ± 1.6, respectively according to the Numeric Rating Scale score; showing significant differences when compared with preoperation (7.5 ± 0.5 and 7.3 ± 0.7, P lt; 0.05). The Numeric Rating Scale score and Oswestry Disabil ity Index in all patients were improved obviously when compared with before operation (P lt; 0.05). During the follow-up period, there was no instrumentation failure or correction loss and the fusion rate was up to 100%. Conclusion For spinal stenosis associated with LDK patients, the most important therapic purpose is to improve cl inical symptom through reconstruction lumbar stabil ization and spinal biomechanics l ine in sagittal plane. Overall estimate of the cl inical appearance and imageology character is necessary when making decision of which segments needed to be fixation and fusion. Individual ized treatment strategy may be the best choice.