Instrumented posterolateral lumbar fusion using coralline hydroxyapatite with or without demineralized bone matrix, as an adjunct to autologous bone.

BACKGROUND CONTEXT: Autogenous posterolateral fusion with and without instrumentation has been reported with good results. However, difficult-to-fuse patients, such as smokers, elderly patients with poor bone quality and/or quantity, or patients with prior posterior surgeries, may have somewhat lower fusion rates. PURPOSE: To determine the efficacy of coralline hydroxyapatite with or without demineralized bone matrix as a bone graft extender in a human clinical model with long-term follow-up. STUDY DESIGN/SETTING: A retrospective series of 40 patients undergoing instrumented autogenous posterolateral lumbar fusion augmented with coralline hydroxyapatite with or without demineralized bone matrix. PATIENT SAMPLE: Long-term clinical and radiographic follow-up were examined for 40 patients who underwent an instrumented posterolateral fusion only. Patients undergoing anterior lumbar interbody fusion (ALIF) procedures were not considered part of the sample. METHODS: All patients underwent successful transpedicular fixation with autogenous posterolateral lumbar fusion. Fifteen cc of Pro Osteon 500 coralline hydroxyapatite (Interpore Cross International, Irvine, CA) was used at each level. An additional 10 cc of Grafton demineralized bone matrix gel (Osteotech, Eatontown, NJ) was used in 70% of these patients. RESULTS: An overall fusion rate of 92.5% was achieved. Pain and function improvement were good but somewhat age dependent and correlated with the number of comorbidities. Patients with Grafton DBM gel had a lower fusion rate of 89.3%. CONCLUSIONS: Based on this small retrospective review, coralline hydroxyapatite is an effective bone graft extender in difficult-to-fuse patients as an adjunct to autologous bone for posterolateral fusion of the lumbar spine when combined with rigid instrumentation.     

后路椎体间融合术治疗腰椎节段性不稳定

目的：探讨后路椎体间融合术(PLIF手术)治疗腰椎节段性不稳定的临床疗效，比较不同种类的椎间融合技术。方法：本组采用3种PLIF手术治疗腰椎节段性不稳定患者72例，共82个节段。其中椎体滑脱28例，间盘突出合并节段性不稳定19例，不稳定型椎管狭窄25例。3种椎间融合技术包括：单纯植骨、双侧椎问支撑器、单侧斜行椎间支撑器，术中均采用椎弓根固定系统辅助，后2种方法中在安放内置物的同时，均辅以椎间自体骨屑植骨。结果：术后随访6个月～5年8个月，平均3年6个月。4～6个月后均达骨性愈合，无固定螺钉松动、断裂及再滑脱现象。患者的腰痛、下肢疼痛症状均有明显缓解，绝大多数病人恢复原正常的工作和生活。VAS疼痛分值术前平均为7.4分，术后下降至3.1分。功能评定结果：优41例，良24例，可7例，差0例，优良率为90．28％。结论：PLIF手术是治疗腰椎不稳症的一种可靠手段，只要把握手术适应证，可以取得满意的结果。     

Lumbar body fusion with a bioresorbable cage in a goat model is delayed by the use of a carboxymethylcellulose-stabilized collagenous rhOP-1 device.

The purpose of this study was to evaluate the efficacy of recombinant human osteogenic protein-1 (rhOP-1) with a carboxymethylcellulose-stabilized collagenous carrier as a bone graft substitute for instrumented lumbar spinal fusion in an established goat model. Twenty goats received a resorbable poly-L-lactic acid (PLLA) interbody cage packed with either rhOP-1 and its carrier or autologous bone graft. The carrier material was bovine collagen type-1 stabilized with carboxymethylcellulose. The fusion segments were retrieved at 3 or 6 months postimplantation and evaluated by radiographic and histologic analyses. The rhOP-1 graft substitute, used in combination with the resorbable PLLA cage, showed inferior results as compared to autologous bone graft in the goat lumbar fusion model. Whereas four out of five segments from the autograft group were fused after 6 months, none of the four segments receiving the rhOP-1 graft substitute were fused at this time point. Bone ingrowth into the cage was delayed or absent in the experimental group, whereas all autograft specimens showed advanced bone ingrowth (3 months) or fusion (6 months). We suggest that the fusion process was inhibited, because cells were unable to penetrate the rhOP-1 graft material. This led to delayed bone formation and in some cases inadequate tissue formation.     

Anterior lumbar interbody fusion with titanium mesh cages, coralline hydroxyapatite, and demineralized bone matrix as part of a circumferential fusion.

BACKGROUND CONTEXT: Anterior lumbar interbody fusion (ALIF) has become one of the primary choices for eliminating motion between vertebral segments in patients with severe discogenic pain and other lumbar pathologies. Autograft is the gold standard for spinal fusion. However, multiple authors have reported complication and morbidity rates associated with iliac crest harvesting to be as high as 25%. Drawbacks to the use of allograft in the anterior column include slower incorporation rates, the possibility for disease transmission, increasing cost resulting from stringent processing and unavailability on a worldwide basis resulting from religious and economic concerns. PURPOSE: To determine the clinical and arthrodesis efficacy of coralline hydroxyapatite as an osteoconductive bone graft substitute in the anterior lumbar spine using a titanium mesh cage. STUDY DESIGN: A series of 50 patients returning for long-term prospective follow-up, implanted with titanium mesh cages filled with coralline hydroxyapatite and demineralized bone matrix for ALIF as part of a circumferential fusion. PATIENT SAMPLE: Long-term clinical and radiographic follow-up were examined for the first 50 patients undergoing this technique by one surgeon. OUTCOME MEASURES: Pain was measured with a visual analog scale and function was measured with the Oswestry Disability Index. METHODS: All 50 patients underwent successful ALIF with titanium mesh cages, coralline hydroxyapatite and demineralized bone matrix, as well as an autologous posterolateral fusion with rigid posterior instrumentation. Patients filled out follow-up questionnaires and appropriate radiographs were taken. RESULTS: A solid fusion rate of 96% was achieved. Mean pain decrease was 60% overall. A total of 70% of all patients either returned to work or to full home activities at a mean of 8 months after surgery. Ninety percent felt the surgery was successful. CONCLUSIONS: The combination of titanium mesh cages, coralline hydroxyapatite and demineralized bone matrix is effective for anterior interbody fusion of the lumbar spine when used as part of a rigidly instrumented circumferential fusion.     

不同植骨融合术治疗腰椎滑脱症的疗效比较分析

目的：比较3种不同植骨融合术治疗腰椎滑脱症的疗效。方法：自2006年1月至2008年12月共收治腰椎滑脱症患者85例,男36例,女49例;年龄38～65岁,平均51.8岁。采用3种手术方法：后外侧植骨融合术32例（A组）、后路椎体间植骨融合术28例（B组）、前路椎体间植骨融合术25例（C组）。疗效评定采用Nakai评分标准,骨性融合标准采用Suk标准判断。结果：所有患者均获得随访,随访时间均不少于2年。A组：优19例,良9例,中4例;B组：优16例,良9例,中3例;C组：优14例,良8例,中3例。A、B、C组的融合率分别为68.8%（22/32）、92.9%（26/28）、92.0%（23/25）。B、C组的椎间隙高度维持及融合率均优于A组（P〈0.05）。结论：对于治疗腰椎滑脱症,前路及后路椎体间植骨融合术在椎间隙高度维持及融合率优于后外侧植骨融合术,但腰椎滑脱症病情及伴随并发症多样化,应具体根据患者滑脱类型、程度、有无椎间盘突出及神经症状等做出相应的选择。     

应用纳米晶胶原基骨材料行腰椎后外侧融合初步效果分析

目的：探讨在腰椎后外侧植骨融合中应用纳米晶胶原基骨材料(nHAC／PLA)的可行性和效果。方法：随访分析64例腰椎多节段椎板切除减压、后外侧植骨融合辅助椎弓根螺钉内固定治疗各类腰椎退行性疾病的临床疗效，植骨材料采用nHAC／PLA颗粒和自体骨颗粒混合，采用VAS疼痛10分法和中华医学会骨科分会脊柱外科组手术疗效标准评估；腰椎正、侧及屈、伸动力位X线片判定融合情况。结果：所有病例切口愈合良好；1年和1年半复诊术后功能恢复优良率分别为90．3％和94．4％，融合率分别为83．9％和88．9％，假关节发生率为0，椎弓根螺钉无松动和移位。结论：纳米晶胶原基骨材料在腰椎后外侧植骨融合中应用是安全的，具有良好的生物相容性，可作为自体骨移植的补充，两者混合使用效果接近自体骨，弥补了减压过程中自体骨的不足．避免再取髂骨。     

Circumferential and posterolateral fusion for lumbar disc disease

Clinical outcome of low back fusion is unpredictable. There are various reports discussing the merits and clinical outcome of these two procedures. The patients were selected from a population of patients who had chronic low back pain unresponsive to conservative treatment. Thirty-six instrumented posterolateral fusions and 35 instrumented circumferential fusions with posterior lumbar interbody fusions were done simultaneously. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging scans, and provocative discography in all the patients. Posterolateral fusion or anterior lumbar interbody fusion was done for internal disc disruption. The Oswestry disability index, subjective scoring, and assessment of fusion were done at a minimum followup of 2 years. On subjective scoring assessment there was a satisfactory outcome of 63.9% (23 patients) in the posterolateral fusion group and 82.8% (29 patients) in the posterior lumbar interbody fusion group. On assessment by the Oswestry index no difference was found in outcome between the two groups. The posterolateral fusion group had a 63.9% satisfactory outcome and the posterior lumbar interbody fusion group had an 80% satisfactory outcome using the Oswestry disability index for postoperative assessment. There was 61.1% improvement in working ability in the posterolateral fusion group and 77.1% improvement in the posterior lumbar interbody fusion group which was not statistically significant. The authors consider instrumented circumferential fusion with posterior lumbar interbody fusion better than instrumented posterolateral fusion for managing chronic disabling low back pain.     

Endoscopic instrumented posterolateral lumbar fusion with Healos and recombinant human growth/differentiation factor-5

OBJECTIVE: The goal of this study was to use a minimally invasive endoscopic surgical technique in a sheep model to evaluate the efficacy of an osteoinductive growth factor, recombinant human growth/differentiation factor-5 (also designated MP52), and an osteoconductive matrix formulation (Healos; DePuy AcroMed, Inc., Mountain View, CA) for inducing and facilitating bone formation. METHODS: Twelve mature sheep underwent bilateral posterolateral lumbar fusion and pedicle screw fixation via a posterior endoscopic approach. Each sheep received two different types of graft material, autogenous iliac crest bone, or a bone graft substitute (MP52 with Healos), inserted into the right and left sides of the spine in an alternating fashion. Groups of four sheep were killed at 2, 4, and 6 months postoperatively for manual, radiographic, and histological evaluation. RESULTS: No neurological impairments, infections, or other complications were observed. After 2 months, partial fusion on both sides was observed, but radiographic evaluation showed greater bone growth on the side that received the bone graft substitute. Solid posterolateral fusion was observed in both autograft and bone graft substitute sites at 4 and 6 months, and autograft and Healos MP52 fusion sites were essentially the same at histological examination. There was no abnormal overgrowth of new bone from either of these two materials. CONCLUSION: Endoscopic posterolateral lumbar arthrodesis and instrumentation is feasible, safe, and effective in a sheep model. Healos is a useful bonding agent that mimics natural bone in posterolateral intertransverse fusion sites. Combined with MP52, it produced fusion comparable to that of autogenous bone graft. Minimally invasive techniques and bone graft substitutes could eliminate morbidity and increase the likelihood of successful fusion.     

Efficacy of silicated calcium phosphate graft in posterolateral lumbar fusion in sheep.

BACKGROUND CONTEXT: Conditions requiring posterior lumbar spinal fusion remain a clinical challenge. Achieving arthrodesis using autogenous bone graft is inconsistent when rigid internal fixation such as transpedicular instrumentation is applied. Synthetic materials, particularly calcium phosphate-based ceramics, have shown promise for spine fusion applications, especially when combined with autograft. Silicate substitution has been shown to enhance the bioactivity of calcium phosphates and may obviate the need for autologous supplementation. PURPOSE: Determine efficacy of silicated calcium phosphate (Si-CaP) compared with autograft to generate solid lumbar fusion. STUDY DESIGN: Comparison of healing of instrumented posterolateral lumbar fusion in ewes at 2 and 6 months using Si-CaP or iliac crest autograft. METHODS: Eighteen skeletally mature ewes underwent implantation of either autograft or Si-CaP in the space spanning the L4-L5 transverse process. In vivo quantitative computed tomography (CT) scans were made at 2-month intervals and after euthanasia. Harvested spine segments were radiographed and biomechanically tested in bending at 6 months. Histological assessments were made at 2 and 6 months. RESULTS: Animals receiving Si-CaP graft were biomechanically and radiographically equivalent to those receiving autograft. Fusion mass density and volume were higher for the Si-CaP group throughout the healing period. Si-CaP regenerated normal bone tissue morphology, cellularity, and maturation with no inflammatory responses despite the fact that no autograft, bone marrow aspirate, or blood was mixed with the material. Histomorphometrically, fusion mass was higher for Si-CaP and bony bridging was equivalent when compared with autograft treatment. CONCLUSIONS: Si-CaP was biomechanically, radiographically, and histologically equivalent to autograft in generating a solid, bony, intertransverse process fusion in an ovine model. Both treatment groups achieved 100% bridging fusion after 6 months of healing.     

骨髓干细胞复合纳米骨用于脊柱融合的研究

目的 探讨骨髓间充质干细胞(BMSCs)复合纳米羟基磷灰石/胶原(nHAC)用于脊柱融合的可行性.方法 将20只新西兰大白兔根据双侧L5～L6横突间植入物不同分为复合材料组和自体髂骨组,每组10只.术后4周每组取材2只,术后8周取材剩余兔,行X线、大体观察、手触检测和组织学观察,评估腰椎融合情况.结果术后8周复合材料组和自体髂骨组融合率分别为75.0%(6/8)和87.5%(7/8),两组融合率差异无统计学意义(P>0.05).结论 BMSCs复合nHAC是一种较好的植骨替代材料,用于脊柱融合可获得与自体骨移植近似地融合效果.     

Posterolateral lumbar spine fusion with INFUSE bone graft.

BACKGROUND CONTEXT: INFUSE has been proven effective in conjunction with threaded cages and bone dowels for single-level anterior lumbar interbody fusion (ALIF). The published experience with posterolateral fusion, although encouraging, utilizes a significantly higher dose and concentration of recombinant human bone morphogenic protein-2 (rhBMP-2) and a different carrier than the commercially available INFUSE. PURPOSE: To present an assessment of fusion rate for posterolateral spine fusion with INFUSE Bone Graft. STUDY DESIGN/SETTING: Retrospective review of patients treated using INFUSE in posterolateral spine fusion in a single institution. PATIENT SAMPLE: 91 patients with minimum 2-year follow-up who underwent posterolateral spine fusion using INFUSE as an iliac crest bone graft (ICBG) substitute. OUTCOME MEASURES: Fusion rate based on fine-cut computed tomographic (CT) scans with sagittal and coronal reconstructions. METHODS: Fusion was performed using one large INFUSE kit (12 mg rhBMP-2, 1.5 mg/mL), which was prepared according to the manufacturer's instructions. The INFUSE sponge was wrapped around the local bone or graft extender and placed over the decorticated surfaces in the lateral gutters. Postoperative CT scans with reconstructions were reviewed by two independent orthopedic spine surgeons. CT scans of a comparison group of 35 patients who underwent primary single-level posterolateral fusion with ICBG were also reviewed. RESULTS: The overall group had a mean 4.38 CT fusion grade and a 6.6% nonunion rate. Primary one-level fusion cases (n=48) had a mean 4.42 fusion grade a 4.2% nonunion rate. Primary multilevel fusions (n=27) had a mean 4.65 CT grade and no nonunions detected. Assessment of the 35 primary one-level ICBG control cases demonstrated a mean CT grade of 4.35 and a nonunion rate of 11.4%. In the 16 cases of revision for prior nonunion, mean CT grade was 3.81 and 4 subjects had nonunions. Additional subgroup analysis showed that smokers (n=14) had a mean 4.32 CT grade with no nonunions. Men had a mean 4.04 CT grade and an 11.1% nonunion rate compared with a mean 4.61 CT grade and 3.6% nonunion rate in women. This difference was statistically significant (p=.036). No significant differences in fusion rate were observed based upon the specific graft extender used (p=.200). CONCLUSIONS: Posterolateral spine fusion involves a more difficult healing environment with a limited surface for healing, a gap between transverse processes and the milieu of distractive forces. Historically, only ICBG has been able to overcome these challenges and reliably generate a successful posterolateral lumbar spine fusion. In contrast to prior studies, clinically available INFUSE delivers only 12 mg rhBMP-2 at a concentration of 1.5 mg/mL. Despite the lower dose and concentration of rhBMP-2, this study suggests that fusion success with INFUSE is equivalent to ICBG for posterolateral spine fusion. As with ICBG, development of solid fusion or nonunion is a multifactorial process. The use of INFUSE is not a substitute for proper surgical technique or optimization of patient-related risk factors. Additional studies are needed to determine the incremental benefit of a greater rhBMP-2 dose or use of alternative carriers for posterolateral fusion. Finally, correlation between radiographic findings and clinical outcomes, and a cost-benefit analysis are needed. Despite these issues, this study presents compelling evidence that commercially available INFUSE is an effective ICBG substitute for one- and two-level posterolateral instrumented spine fusion.     

The use of coralline hydroxyapatite with bone marrow, autogenous bone graft, or osteoinductive bone protein extract for posterolateral lumbar spine fusion

STUDY DESIGN: A posterolateral lumbar arthrodesis animal model using coralline hydroxyapatite as a bone graft substitute. OBJECTIVE: To determine the effectiveness of coralline hydroxyapatite as a bone graft substitute for lumbar spine fusion when used with bone marrow, autogenous bone graft, or an osteoinductive bone protein extract. SUMMARY OF BACKGROUND DATA: Coralline hydroxyapatite is commonly used as a bone graft substitute in metaphysial defects but its use in a more challenging healing environment such as the posterolateral spine remains controversial. There are no published animal studies in which the use of coralline hydroxyapatite has been evaluated in a posterolateral lumbar arthrodesis model. METHODS: Single-level posterolateral lumbar arthrodesis was performed at L5-L6 in 48 adult New Zealand White rabbits. Rabbits were assigned to one of three groups based on the graft material they received: 3.0 mL coralline hydroxyapatite 1.5 mL plus bone marrow; 1.5 mL coralline hydroxyapatite plus 1.5 mL autogenous iliac crest bone; and, 3.0 mL coralline hydroxyapatite plus 500 micrograms bovine-derived osteoinductive bone protein extract on each side. Rabbits were killed after 2, 5, or 10 weeks, and the spines were excised and evaluated by manual palpation, radiographs, tensile biomechanical testing, and nondecalcified histology. RESULTS: Fusions were assessed by manual palpation at 5 weeks for comparisons among the three groups of graft materials. The coralline hydroxyapatite used with bone marrow produced no solid fusions (0/14). When combined with an equal amount of autogenous iliac crest bone, coralline hydroxyapatite resulted in solid fusion in 50% (7/14) of the rabbits (P < 0.05). When combined with the osteoinductive growth factor extract, the coralline hydroxyapatite resulted in solid fusion in 100% (11/11) of the rabbits (P < 0.05). The fusion masses in the growth factor group were significantly stronger (1.8 +/- 0.2 vs. 1.3 +/- 0.1; P = 0.02) and stiffer (1.5 +/- 0.2 vs. 1.2 +/- 0.1, P = 0.04) based on tensile testing to failure when normalized to the adjacent unfused level. CONCLUSION: These data indicate that coralline hydroxyapatite with bone marrow was not an acceptable bone graft substitute for posterolateral spine fusion. When combined with autogenous iliac crest bone graft-coralline hydroxyapatite served as a graft extender yielding results comparable to those obtained with autograft alone. Coralline hydroxyapatite served as an excellent carrier for the bovine osteoinductive bone protein extract yielding superior results to those obtained with autograft or bone marrow.     

Allogeneic mesenchymal progenitor cells for posterolateral lumbar spine fusion in sheep

Background contextOsteoconductive porous ceramic bone graft materials supplemented with mesenchymal precursor cells (MPC) derived from autologous bone marrow aspirates have been shown to stimulate successful interbody and posterolateral spine fusion in preclinical models. Recent advances in immunomagnetic cell sorting have enabled purification and isolation of pluripotent stem cells from marrow aspirates and have expanded stem cell technology to allogeneic cell sources. Allogeneic MPC technology combined with appropriate synthetic biomaterial carriers could provide both the osteogenic and osteoconductive components needed for successful posterolateral spine fusion without the need for autologous bone harvest or expensive recombinant protein technology.PurposeTo determine the safety and efficacy of a hydroxyapatite:tricalcium phosphate graft material supplemented with allogeneic mesenchymal precursor cells in posterolateral lumbar spine fusion using an ovine model.Study designSkeletally mature ewes underwent single-level instrumented posterolateral lumbar spine fusion using either autograft (AG), hydroxyapatite:tricalcium phosphate carrier (CP), or CP supplemented with allogeneic mesenchymal progenitor cells (MPCs). Three doses of MPCs were evaluated: 25 × 10⁶ cells (low dose, LD), 75 × 10⁶ cells (mid dose, MD), and 225 × 10⁶ cell (high dose, HD). Animals survived for either 4 or 9 months.MethodsPlain radiographs were acquired and scored for bridging bone at regular intervals during healing to monitor fusion development. Hematology, coagulation, and serum chemistry were monitored at regular intervals throughout the study to monitor animal health. After necropsy, computed tomography, high-resolution radiography, biomechanical testing, organ pathology, bone histopathology, and bone histomorphometry were conducted to monitor the safety and ascertain the efficacy of MPC treatment.ResultsMPC treatment in this spine fusion model resulted in no observed adverse systemic or local tissue responses. Radiographically, fusion scores for MPC-treated animals were uniformly higher compared with those treated with carrier alone (CP) after 3 months and continued the same trend throughout 9 month of healing. Quantitative computed tomography confirmed better connectivity of the fusion for MPC treatment groups compared with CP. Biomechanical analyses were not able to differentiate between treatment groups. Histomorphometry results confirmed radiographic and quantitative computed tomography results; cell-supplemented treatment groups and autograft had equivalent amounts of bone within the fusion mass and less bony fusion tissue was found within the fusion mass in specimens from the CP treatment group. No conclusive effects of cell dose of fusion efficacy were noted.ConclusionsAdult allogeneic mesenchymal precursor cells delivered via a hydroxyapatite:tricalcium phosphate carrier were both safe and efficacious in this ovine spine fusion model. Results from this preclinical study support that allogeneic mesenchymal precursor cells produced fusion efficacy similar to that achieved using iliac crest autograft, thereby providing a safe and viable option to achieve successful posterolateral spine fusion.     

The First Clinical Trial of Beta-Calcium Pyrophosphate as a Novel Bone Graft Extender in Instrumented Posterolateral Lumbar Fusion

Background

Porous β-calcium pyrophosphate (β-CPP) was developed to improve the fusion success of posterolateral lumbar fusion (PLF). The possibility of accomplishing PLF using a mixture of porous β-CPP and iliac bone was studied. This paper reports the radiologic results of PLF using the β-CPP plus autograft for lumbar degenerative disease as a bone graft extender.

Methods

A prospective, case-matched, radiographic study evaluating the results of short segment lumbar fusion using a β-CPP plus autograft was performed to compare the efficacy of β-CPP plus autograft with that of an autograft alone for short segment lumbar fusion. Thirty one consecutive patients (46 levels) underwent posterolateral fusion with pedicle screw fixation and additional posterior lumbar interbody fusion. In all patients, 3 mL of β-CPP plus 3 mL of autogenous bone graft was placed randomly in one side of a posterolateral gutter, and 6 mL of autogenous iliac bone graft was placed on the other. The fusion rates, volumes of fusion masses, and bone absorption percentage were evaluated postoperatively using simple radiographs and 3 dimensional computed tomography (3D-CT) scans.

Results

The control sides treated with an autograft showed significantly better Lenke scores than the study sides treated with β-CPP at 3 and 6 months postoperatively, but there was no difference between the two sides at 12 months. The fusion rates (confirmed by 3D-CT) were 87.0% in the β-CPP group and 89.1% in the autograft group, which were not significantly different. The fusion mass volumes and bone absorption percentage at 12 months postoperatively were 2.49 mL (58.4%) and 1.89 mL (69.5%) for the β-CPP and autograft groups, respectively, and mean fusion mass volume was significantly higher in the β-CPP group.

Conclusions

β-CPP combined with an autograft is as effective as autologous bone for grafting during instrumented posterolateral spinal fusion. These findings suggest that β-CPP bone chips can be used as a novel bone graft extender for short-segment posterolateral spinal fusion.     

Clinical and radiographic assessment of transforaminal lumbar interbody fusion using HEALOS collagen-hydroxyapatite sponge with autologous bone marrow aspirate

Background contextStudies have suggested that the use of bone marrow aspirate (BMA) with HEALOS (DePuy Spine, Raynham, MA), a collagen-hydroxyapatite sponge (CHS), is an effective substitute for autologous iliac crest bone graft when used in fusion procedures of the lumbar spine.PurposeTo assess clinical and radiographic outcomes after implantation of BMA/CHS in patients undergoing transforaminal lumbar interbody fusion (TLIF) with posterolateral fusion (PLF).Study design/settingCase series radiographic outcome study.Patient sampleTwenty patients.Outcome measuresRadiographs/computed tomography (CT) scans.MethodsFrom September 2003 to October 2004, 20 patients (22 interbody levels) were implanted with BMA/CHS via TLIF/PLF with interbody cages and posterior pedicle screws. All patients were retrospectively identified and invited for a 2-year prospective follow-up. Plain radiographs with dynamic films and CT scans were taken, and fusion was assessed in a blinded manner.ResultsFollow-up averaged 27 months (range: 24–29). Primary diagnosis included spondylolisthesis (17 patients), scoliosis with asymmetric collapse (2 patients), and postdiscectomy foraminal stenosis (1 patient). The overall fusion rate was 95% (21/22 levels, 19/20 patients). Anteriorly bridging bone was observed in 91% of the anteriorly fused levels (20/22), of which 65% (13/20) occurred through and around the cage and 35% (7/20) around the cage only. Unilateral or bilateral bridging of the posterior fusion masses was observed in 91% (20/22), with 55% occurring bilaterally (12/22). In 4 (18%) cases, bridging only occurred either posteriorly (2 cases) or anteriorly (2 cases). Complications included one deep wound infection.ConclusionsAt the 2-year follow-up, BMA/CHS showed acceptable fusion rates in patients undergoing TLIF/PLF, and can be considered as an alternative source of graft material.     

The efficacy of autologous laminectomy bone combined with bone graft extenders in posterolateral lumbar instrumented fusion

Iliac crest autograft has been used successfully for many years in spinal fusion operations. The main advantages to iliac crest autograft are the easy accessibility, the robust combination of osteogenic, osteoinductive, and osteoconductive properties, and the resultant efficacy. However, autograft iliac crest bone graft has fallen out of favor in spinal fusion operations due to the morbidity associated with harvest. Various bone graft substitutes have become commercially available that provide similar fusion rates when compared to iliac crest autograft. None of the bone graft substitutes can match iliac crest bone graft in all 3 osteogenic, osteoinductive, and osteoconductive parameters, but when combined with local autologous laminectomy bone and, therefore, used as a bone graft extender, may very well come close. This article reviews the main categories of bone graft substitutes and extenders and the role of these substances when combined with local autologous laminectomy bone in posterolateral lumbar instrumented fusion operations.     

The use of rhBMP-2 in interbody fusion cages. Definitive evidence of osteoinduction in humans: a preliminary report

STUDY DESIGN: A prospective randomized controlled human clinical pilot trial. OBJECTIVES: To determine the feasibility of using rhBMP-2/collagen as a substitute for autogenous bone graft inside interbody fusion cages to achieve arthrodesis in humans. SUMMARY OF BACKGROUND DATA: Preclinical studies have shown rhBMP-2 to be an effective substitute for autogenous bone graft, but there are no studies to date documenting such efficacy for human spine fusion. METHODS: Fourteen patients with single-level lumbar degenerative disc disease refractory to nonoperative management were randomized to receive lumbar interbody arthrodesis with a tapered cylindrical threaded fusion cage filled with rhBMP-2/collagen sponge or autogenous iliac crest bone. Patients were evaluated with radiographs, sagittally reformatted computed tomography scans, and Short Form-36 and Oswestry outcome questionnaires. RESULTS: All 11 patients who received rhBMP-2 were judged by three independent radiologists to have solid fusions (at 6, 12, and 24 months postimplantation), whereas only 2 of the 3 control patients, who received the standard treatment of autogenous iliac crest bone, were deemed to be fused. The Oswestry Disability Questionnaire scores of the rhBMP-2 group improved sooner (after 3 months) than those of the autograft group, with both groups demonstrating similar improvement at 6 months. Short Form 36 scores continued to improve up to 24 months. CONCLUSION: The arthrodesis was found to occur more reliably in patients treated with rhBMP-2-filled fusion cages than in controls treated with autogenous bone graft, although the sample size was limited. There were no adverse events related to the rhBMP-2 treatment. This study is one of the first to show consistent and unequivocal osteoinduction by a recombinant growth factor in-humans.     

后路减压植骨融合RF内固定治疗腰椎滑脱症

目的：探讨后路应用RF椎弓根螺钉复位固定、减压、椎体间及后外侧植骨融合治疗腰椎滑脱症的疗效。方法：对87例腰椎滑脱症患者行后路椎管减压，应用RF椎弓根螺钉系统对滑脱椎体进行复位固定，椎体间和后外侧植骨融合。结果：随访9—48个月，临床优良率89．7％，腰椎滑脱复位率96．7％，6-12个月复查X线片均显示椎体间骨性融合，椎体间高度较术前明显增大。结论：RF椎弓根螺钉系统能有效撑开提拉滑脱椎体，复位满意，固定力强，并为彻底减压提供有效空间。采用椎体间联合后外侧植骨能有效提高植骨融合率。     

自体骨髓基质干细胞与钙磷陶瓷复合体在恒河猴腰椎前路融合中的实验研究

目的 评价自体骨髓基质干细胞（BMSCs）与钙磷生物陶瓷复合体的成骨效果。方法2003年3月至2005年4月,对9只成熟恒河猴行经腹膜外L3-4和L5-6腰椎间盘切除脊柱融合术。每只动物的两个脊柱节段随机接受3种治疗方法中的2种：自体髂骨移植（自体骨组,n=6）,空载体陶瓷移植物（陶瓷组,n=6）和骨髓基质干细胞-陶瓷复合体（BMSCs组,n=6）。自髂骨抽取骨髓,在含有成骨细胞诱导因子的培养液中体外扩增自体BMSCs,利用旋转培养方法构建骨髓基质干细胞-钙磷陶瓷复合体供移植用。实验动物在术后3个月处死,利用放射学、生物力学测试、组织学和组织形态计量学观察和分析脊柱融合节段。结果生物力学测试结果和组织学结果显示BMSCs组的椎体间脊柱融合效果明显好于陶瓷组;BMSCs组和自体骨组显示出近似的生物力学强度。BMSCs组和自体骨组的骨量显著多于陶瓷组;但陶瓷组的陶瓷材料残余量显著多于BMSCs组。结论在恒河猴椎体间脊柱融合模型中,自体骨髓基质干细胞和钙磷生物陶瓷复合体在移植入体内3个月内有良好的成骨并获得椎体间骨性融合。     

Posterolateral and anterior interbody spinal fusion models in the sheep

Posterolateral and anterior interbody spinal arthrodesis is a frequent procedure, but high nonunion rates are reported and harvesting autologous bone graft from the iliac crest significantly increases morbidity. Bone graft substitutes are an alternative, but to date clinical results are not conclusive. Bone substitutes can be organic or inorganic, biologic or synthetic. They can have osteoconductive properties, inductive properties or both. Animal experiments are essential to investigating bone substitutes using biomechanical and histologic methods not available in clinical studies. Few authors reported on instrumented anterior fusion models, but none used the sheep model. In the current study posterolateral and anterior interbody fusion models in sheep are described. Both models used instrumented fusions, applying porous mineral scaffolds, alone or mixed with bone. The surgical techniques are described step-by-step and potential difficulties are highlighted. Preliminary results are reported for the posterolateral fusion model using coralline graft substitutes. The coral granules mixed with locally harvested bone had fusion outcomes similar to pure autologous bone. The graft substitute showed marked resorption between 12 and 20 weeks. All fusions had bone cortex and good trabecular connectivity. Histologic evaluation suggests after 20 weeks nearly the entire surface of the substitute is covered with new bone. Porous mineral bone substitutes mixed with locally harvested autologous bone are thought to be a valid alternative for posterolateral fusions.