Clinical efficacy of three types of autogenous bone grafts in treatment of single-segment thoracic tuberculosis: A retrospective cohort study.

A retrospective study investigated and compared the results of lamina with spinous process (LSP), transverse process strut (TPS) and iliac graft (IG) as bone graft in thoracic single-segment spinal tuberculosis(TB) with the one-stage posterior approach of debridement, fusion and internal instrumentation. 99 patients treated from January 2012 to December 2015 were reviewed. LSP was performed in 35 patients (group A), TPS was undertaken in 33 patients (group B), and IG was carried out in 31 patients (group C). Surgical time, blood loss, hospitalization time, drainage volume, and follow-up (FU) duration were recorded. The visual analog scale (VAS), Oswestry Disability Index (ODI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), American Spinal Injury Association (ASIA) grade, segmental angle, intervertebral height and bone fusion time were compared between preoperative and final FU. All the patients were followed up for a mean 43.90±10.39 months in group A, 45.30±6.20 months in group B, 44.32±7.17 months in group C without difference(P>0.05). The mean age was younger, the blood loss was less, the hospitalization time and the surgical time were shorter in group A than those in group B and C (P<0.05). The drainage volume was less in group A than that in group B and group C. The CRP, ESR, VAS, and ODI were significantly decreased and there were no significant difference among the groups at the final FU. The neurological function after surgery was improved compared with preoperation among the groups. The bony fusion at a mean time 12.90±3.91 months in group A was longer than that in group B (6.75±1.55 months) and group C (5.52±1.64 months) (P<0.05). No significant difference was found at the mean segmental angle, mean intervetebral height of preoperation and final FU among the groups (P>0.05). In conclusion, the LSP and TPS as bone graft are reliable, safe, and effective for single-segment stability reconstruction for surgical management of thoracic TB and TPS could be new bone graft methods.

Biomechanical properties of 3D-printed bone scaffolds are improved by treatment with CRFP.

BACKGROUND: One of the major challenges in orthopedics is to develop implants that overcome current postoperative problems such as osteointegration, proper load bearing, and stress shielding. Current implant techniques such as allografts or endoprostheses never reach full bone integration, and the risk of fracture due to stress shielding is a major concern. To overcome this, a novel technique of reverse engineering to create artificial scaffolds was designed and tested. The purpose of the study is to create a new generation of implants that are both biocompatible and biomimetic. METHODS: 3D-printed scaffolds based on physiological trabecular bone patterning were printed. MC3T3 cells were cultured on these scaffolds in osteogenic media, with and without the addition of Calcitonin Receptor Fragment Peptide (CRFP) in order to assess bone formation on the surfaces of the scaffolds. Integrity of these cell-seeded bone-coated scaffolds was tested for their mechanical strength. RESULTS: The results show that cellular proliferation and bone matrix formation are both supported by our 3D-printed scaffolds. The mechanical strength of the scaffolds was enhanced by trabecular patterning in the order of 20% for compression strength and 60% for compressive modulus. Furthermore, cell-seeded trabecular scaffolds modulus increased fourfold when treated with CRFP. CONCLUSION: Upon mineralization, the cell-seeded trabecular implants treated with osteo-inductive agents and pretreated with CRFP showed a significant increase in the compressive modulus. This work will lead to creating 3D structures that can be used in the replacement of not only bone segments, but entire bones.

Lumbar intervertebral disc allograft transplantation: healing and remodelling of the bony structure.

Previous human study suggested that fresh-frozen intervertebral disc allograft transplantation can relieve neurological symptoms and restore segmental kinematics. Before wide clinical application, research into the pathophysiology of the postoperative disc allograft is needed. One important question that remains to be answered in disc allografting is the healing process of the host-graft interface and the subsequent change of the endplates. With the goat model for lumbar disc allografting, histology, micro-computed tomography analysis, scanning electron microscopy and energy-dispersive X-ray spectroscopy mapping were applied to evaluate the healing of the host-graft interfaces, the remodelling of subchondral bone, and the changes of the bony and cartilaginous endplates after transplantation. It was found that healing of the host-graft interfaces started at 1.5 months and was completed at 6 months by natural remodelling. This bony remodelling was also noted in the subchondral bone area after 6 months. The bony endplate was well preserved initially, but was gradually replaced by trabecular bone afterwards; on the other hand, the cartilaginous endplate became atrophic at 6 months and nearly disappeared at the final follow-up. Collectively, after intervertebral disc allograft transplantation, bony healing and remodelling were seen which ensured the stability and mobility of the disc-transplanted segment, but the integrity of bony and cartilaginous endplates was gradually lost and nearly disappeared finally.

Comparison of the PEEK cage and an autologous cage made from the lumbar spinous process and laminae in posterior lumbar interbody fusion.

BACKGROUND: A prospective cohort study was performed to evaluate the clinical and radiological outcomes following posterior lumbar interbody fusion (PLIF) in patients treated with a PEEK cage compared to those treated with an autologous cage using the lumbar spinous process and laminae (ACSP). METHODS: Sixty-nine consecutive patients with lumbar degenerative disc disease were randomly assigned to either a PEEK cage (group A, n = 34) or an ACSP (group B, n = 35). Monosegmental PLIF was performed in all patients. Mean lumbar lordosis, mean disc height, visual analog scale (VAS) scores, functional outcomes, fusion rates and complication rates were recorded and compared. The patients were followed postoperatively for a minimum of 2 years. RESULTS: Successful radiographic fusion was documented in all patients. No flexion-extension hypermobility or pedicle screw loosening or breakage occurred during the follow-up period. No significant difference existed between the 2 groups when comparing the mean lumbar lordosis, mean disc height, visual analog scale (VAS) scores, functional outcomes, fusion rates or complication rates. Overall satisfactory results were achieved in both groups. CONCLUSIONS: The results suggest that the ACSP appears to be equally as safe and effective as the PEEK cage. TRIAL REGISTRATION: ISRCTN25558534 . Retrospectively registered 16/02/2016.

Radiological evaluation of anterior lumbar fusion using PEEK cages with adjacent vertebral autograft in spinal deformity long fusion surgeries.

PURPOSE: The aim of this study was to evaluate the radiographic characteristics of polyetheretherketone (PEEK) cages packed with adjacent vertebral autograft material in lumbar anterior lumbar interbody fusion (ALIF) in spinal deformity long fusion surgeries. METHODS: This is a retrospective radiographic study. From April 2008 to April 2012, 40 patients (5 males and 35 females, mean age 67 ± 9 years) with coronal and/or sagittal spine deformities underwent staged corrective surgery combined with lumbar ALIF using PEEK cages at the L3-L4, L4-L5 or L5-S1 segment with posterior long (≥ 4 levels) instrumentation. The mean follow-up time was 27.5 months (13-49 months). We examined the interbody fusion rate and cage subsidence at 3 months postoperatively and final follow-up. Additionally, we evaluated the distance of cage migration at final follow-up and the improvement in lumbar lordosis. The rate of "collapse" of the adjacent vertebra where the autograft was harvested was assessed at the final follow-up. Finally, we examined the cage-related postoperative complications in this series. RESULTS: Solid interbody fusion was achieved in 96.4 % (81/84) of the levels at the final follow-up. A mild forward cage migration was observed, and the mean migration distance at final follow-up was 0.83 mm in L3/4, 0.36 mm in L4/5 and 0.55 mm in L5/S1. There was cage subsidence observed in 8.3 % (7/84) of the levels. In all patients, the PEEK cage maintained a significant increase in segmental lordosis at all postoperative visits. However, a mild reduction in segmental lordosis still occurred with time. The adjacent lumbar vertebral bodies where the autografts were harvested appeared to be intact in height radiologically at the final follow-up. There were no postoperative complications due to bone harvesting or cage insertion. Proximal junctional kyphosis was found in one patient who underwent a subsequent revision surgery. CONCLUSIONS: The use of lumbar ALIF with PEEK cages and adjacent vertebral autografts in spinal deformity long fusion surgeries is an effective and safe procedure. The allograft filler is safe and effective in maintaining the shape of harvested vertebrae. Additional long-term follow-up studies are needed to further justify its use.

[Treatment of thoracolumbar burst fracture with subtotal vertebrectomy, decompression and strut grafting through posterolateral approach].

OBJECTIVE: To explore the clinical effect of subtotal vertebrectomy, decompression and strut grafting in treating thoracolumbar burst fractures through posterolateral approach via posterior midline incision. METHODS: From May 2005 to July 2008, 14 patients with thoracolumbar burst fractures were treated with subtotal vertebrectomy, decompression and strut grafting through posterolateral approach via posterior midline incision. There were 9 males and 5 females, ranging in age from 24 to 68 years, with an average of 42.3 years. All patients were single segment fractures, of them, T11 was in 1 case, T12 in 5, L1 in 5 and L2 in 3. According to AO classification in spinal fracture, type A3 was in 5 cases, B1 in 3, B2 in 3, C1 in 2, C2 in 1. According to the ASIA classification in neurological function, grade A was in 3 cases, B in 3, C in 5, D in 2, E in 1. The height of anterior border vertebral body, volume of spinal canal and neurological function were analyzed by X-ray films, CT scanning and ASIA classification preoperative, postoperative and at final follow-up. RESULTS: Operative time was from 3.5 to 5.5 hours with the mean of 4.0 hours; bleeding during operation was from 800 to 2 600 ml with the mean of 1 300 ml. Two cases with nerve root injury recovered without special handling after 3-6 months; 1 case with leakage of cerebrospinal fluid restored through lumbar cerebrospinal fluid drainage; 1 case with pleura tear healed through closed thoracic drainage. No iatrogenic vascular injury or infection was found. The follow-up time was from 8 to 36 months with the mean of 16.5 months. All patients had neurofunctional recovery at different degree, except that 3 patients in grade A. The height of anterior border vetebral body restored from (42.25 +/- 11.87)% preoperatively to (94.38 +/- 3.08)% postoperatively, and (92.87 +/- 3.32)% at final follow-up (P<0.05); volume of spinal canal (the actual volume of spinal canal/normal volume of spine canal) increased from (45.63 +/- 6.88)% preoperatively to (95.26 +/- 3.31)% postoperatively, and (96.13 +/- 2.56)% at final follow-up (P<0.05). Cobb angle were corrected from (25.64 +/- 4.40) degrees preoperatively to (5.80 +/- 1.14) degrees postoperatively; Cobb angle lost from 0 degrees to 6 degrees at final follow-up with (8.10 +/- 2.65) degrees. All patients obtained complete bony fusion without pseudarthrosis formation at final follow-up. CONCLUSION: Subtotal vertebrectomy decompression and strut grafting through posterolateral approach via posterior midline incision is an effective and safe method in treating thoracolumbar burst fracture, which can restored height of intervertebral body, volume of spinal canal and physiological flexion of spinal column, and retain spinal permanent stability.

Local bone graft harvesting and volumes in posterolateral lumbar fusion: a technical report.

BACKGROUND CONTEXT: In lumbar surgery, local bone graft is often harvested and used in posterolateral fusion procedures. The volume of local bone graft available for posterolateral fusion has not been determined in North American patients. Some authors have described this as minimal, but others have suggested the volume was sufficient to be reliably used as a stand-alone bone graft substitute for single-level fusion. PURPOSE: To describe the technique used and determine the volume of local bone graft available in a cohort of patients undergoing single-level primary posterolateral fusion by the authors harvesting technique. STUDY DESIGN: Technical description and cohort report. PATIENT SAMPLE: Consecutive patients undergoing lumbar posterolateral fusion with or without instrumentation for degenerative processes. OUTCOME MEASURE: Local bone graft volume. METHODS: Consecutive patients undergoing lumbar posterolateral fusion with or without instrumentation for degenerative processes of were studied. Local bone graft was harvested by a standard method in each patient and the volume measured by a standard procedure. RESULTS: Twenty-five patients were studied, and of these 11 (44%) had a previous decompression. The mean volume of local bone graft harvested was measured to be 25 cc (range, 12-36 cc). Local bone graft was augmented by iliac crest bone in six of 25 patients (24%) if the posterolateral fusion bed was not well packed with local bone alone. There was a trend to greater local bone graft volumes in men and in patients without previous decompression. CONCLUSION: Large volumes of local bone can be harvested during posterolateral lumbar fusion surgery. Even in patients with previous decompression the volume harvested is similar to that reported harvested from the posterior iliac crest for single-level fusion.

One, two-, and three-level instrumented posterolateral fusion of the lumbar spine with a local bone graft: a prospective study with a 2-year follow-up.

STUDY DESIGN: Prospective trial. OBJECTIVE: To examine the difference in bone union and clinical results after one-, two-, and three-level instrumented posterolateral fusion surgery using a local bone graft. SUMMARY OF BACKGROUND DATA: The iliac crest bone graft technique for lumbar posterolateral fusion surgery is widely used; however, donor site problems such as pain and sensory disturbance have been reported. Local bone has been used for fusion surgery; however, its reliability as a graft for multiple segments has not been fully reported. METHODS: One hundred twenty-two patients diagnosed with degenerated spondylolisthesis were divided into three groups [spondylolisthesis at 1 level (n = 42), at 2 levels (n = 40), and at 3 levels (n = 40)]. All patients underwent decompression and instrumented posterolateral fusion with a local bone graft. The amount of bone graft, proportion of patients with (rate) and duration of bone union, Visual Analog Scale (VAS) score, Japanese Orthopedic Association Score (JOAS), and Oswestry Disability Index (ODI) were evaluated before and 2 years after therapy. RESULTS: VAS score, JOA score, and ODI were not significantly different among the three groups before and after surgery (P > 0.05). Average amount of local bone graft used for one segment significantly decreased in proportion to the number of fusion levels (P < 0.05). The rate of bone union was 88% in the one-level group, 85% in the two-level group, and 62.5% in the three-level group, which was significantly lower than that in the one- and two-level groups (P < 0.05). CONCLUSION: If one- and two-level posterolateral fusion were performed, the local bone graft technique provides a good and uniform bone union rate; however, for three-level fusion poor results were obtained because of an insufficient amount of local bone.

[Clinical observation of bone graft and impaction on posterior interbody fusion for lumbar instability].

OBJECTIVE: To investigate the clinical effect and indication of bone graft and impaction on posterior interbody fusion for lumbar instability. METHODS: From January 2001 to July 2008, 95 patients with lumbar instability were treated by bone graft and impaction on posterior interbody fusion. Including 41 males and 54 females, the age from 45 to 76 years old with an average of 59 years. There were 68 cases with single level, 22 cases with two-level, 5 cases with three-level in patients, which were 127 intervertebral space altogether. The neural canal and affected side nerve root were decompressed thoroughly during operation. Resected the disc from the affected side and erased the cartilage to plate extensively combined with pedicle screw fixation, and impaction on interbody fusion with the excisional vertebral plate bone was achieved. To assess the improvement of the patients' symptom, sign, and JOA scores pre and post operatively. Meanwhile, the changes of intervertebral height from the lumbar radiographs were measured and the degrees of interbody bone fusion were evaluated according to SUK method. RESULTS: All the 95 patients were followed up from 12 to 90 months with the mean of 44.8 months. All the clinical symptom were improved significantly or disappeared completely. All the 127 intervertebral space achieved good bone fusion. There was no displacement of bone graft and severe complication happened. According to the radiograph, all the intervertebral heights were increased obviously. The mean JOA score improved from 11.3 +/- 3.3 preoperative to 25.1 +/- 2.8 at 8 weeks postoperative; achieved 24.8 +/- 3.2 with followed up at the last time (P < 0.001). CONCLUSION: Bone graft and impaction on posterior interbody fusion was one of the most effective methods for the lumbar instability. It has extensive range of application, and it's suitable for senile lumbar degeneration instability especially.

[Progressing study in treating discogenic low back pain].

Lumbago is a general, frequently and complicated clinical symptom. 60% to 80% in adults suffer from back pain of varying degrees. The pain causing by various pathological changes stimulateing the ache receptor in intervertebral disc is call discogenic low back pain. Along with people knowing more and more about this disease, all kinds of treatment techniques are applied in clinic. But the indication and therapeutic effects are both evidently different. Below is a summary of the therapic method about discogenic low back pain based on international and domestic reference data of recent years and the author's clinical experiences.

Harvesting local cylinder autograft from adjacent vertebral body for anterior lumbar interbody fusion: surgical technique, operative feasibility and preliminary clinical results.

Autogenous iliac crest has long served as the gold standard for anterior lumbar arthrodesis although added morbidity results from the bone graft harvest. Therefore, femoral ring allograft, or cages, have been used to decrease the morbidity of iliac crest bone harvesting. More recently, an experimental study in the animal showed that harvesting local bone from the anterior vertebral body and replacing the void by a radio-opaque beta-tricalcium phosphate plug was a valid concept. However, such a concept precludes theoretically the use of posterior pedicle screw fixation. At one institution a consecutive series of 21 patients underwent single- or multiple-level circumferential lumbar fusion with anterior cages and posterior pedicle screws. All cages were filled with cancellous bone harvested from the adjacent vertebral body, and the vertebral body defect was filled with a beta-tricalcium phosphate plug. The indications for surgery were failed conservative treatment of a lumbar degenerative disc disease or spondylolisthesis. The purpose of this study, therefore, was to report on the surgical technique, operative feasibility, safety, benefits, and drawbacks of this technique with our primary clinical experience. An independent researcher reviewed all data that had been collected prospectively from the onset of the study. The average age of the patients was 39.9 (26-57) years. Bone grafts were successfully harvested from 28 vertebral bodies in all but one patient whose anterior procedure was aborted due to difficulty in freeing the left common iliac vein. This case was converted to a transforaminal interbody fusion (TLIF). There was no major vascular injury. Blood loss of the anterior procedure averaged 250 ml (50-350 ml). One tricalcium phosphate bone plug was broken during its insertion, and one endplate was broken because of wrong surgical technique, which did not affect the final outcome. One patient had a right lumbar plexopathy that was not related to this special technique. There was no retrograde ejaculation, infection or pseudoarthrosis. One patient experienced a deep venous thrombosis. At the last follow up (mean 28 months) all patients had a solid lumbar spine fusion. At the 6-month follow up, the pain as assessed on the visual analog scale (VAS) decreased from 6.9 to 4.5 (33% decrease), and the Oswestry disability index (ODI) reduced from 48.0 to 31.7 with a 34% reduction. However, at 2 years follow up there was a trend for increase in the ODI (35) and VAS (5). The data in this study suggest that harvesting a cylinder of autograft from the adjacent vertebral body is safe and efficient. Filling of the void defect with a beta-tricalcium phosphate plug does not preclude the use of posterior pedicle screw stabilization.

Biomechanical analysis of anterior poly-methyl-methacrylate reconstruction following total spondylectomy for metastatic disease.

STUDY DESIGN: Three reconstruction options were evaluated biomechanically following total spondylectomy using human cadaveric spine specimens. OBJECTIVES.: To evaluate and compare the stability of combined anterior and posterior fixation incorporating poly-methyl-methacrylate with alternative accepted reconstruction techniques. SUMMARY OF BACKGROUND DATA: Total spondylectomy represents the most radical option for decompression in metastatic spinal cord compression. Poly-methyl-methacrylate is considered a useful adjunct in spinal column stabilization and arthrodesis; however, there is little published biomechanical data to support its use in this setting. METHODS: Ten fresh-frozen human cadaveric spines (T9-L3) were used. After intact analysis, a total spondylectomy was performed at T12. Three potential reconstruction techniques were tested for their ability to restore stiffness to the specimen: 1) multilevel posterior pedicle screw instrumentation from T10-L2; 2) anterior instrumentation (ATL Z plate II) and rib graft at T11-L1 with multilevel posterior pedicle screw instrumentation from T10-L2; and 3) anterior cement (Simplex P) and pins construct (T12) with multilevel posterior pedicle screw instrumentation from T10-L2. Each of the three potential reconstruction techniques was tested on each specimen in random order using nondestructive testing under load control. RESULTS: Only combined stabilization techniques (e.g., anterior instrumentation and rib graft with multilevel posterior pedicle screw instrumentation and anterior cement-and-pins construct with multilevel posterior pedicle screw instrumentation) restored stiffness to a level equivalent to or higher than that of the intact spine in all loading modes (P < 0.05). Anterior cement-and-pins construct with multilevel posterior pedicle screw instrumentation provided more stability to the specimen than anterior instrumentation and rib graft with multilevel posterior pedicle screw instrumentation in compression and flexion testing (P < 0.05). Posterior instrumentation alone did not restore stiffness to the intact level in compression and flexion testing (P < 0.005). CONCLUSIONS: Combined anterior and posterior reconstruction using a cement construct provides equal to or more stability than the intact spine in all testing modes. Posterior stabilization alone is an inferior method of reconstruction following total spondylectomy. Poly-methyl-methacrylate has the advantage over traditional anterior reconstruction techniques in that it can be inserted using a posterior approach.

Autoenxerto de crista ilíaca de coelhos na união vertebral dorsolateral lombar / Iliac crest autograft in rabbit dorsolateral spinal fusion

Foi realizada artrodese dorsolateral das vértebras lombares L5-L6 de coelhos, avaliando-se a eficácia do autoenxerto da crista ilíaca na promoção de união vertebral. Foram utilizados 33 coelhos da raça Nova Zelândia Branco, distribuídos em dois grupos, com nove indivíduos no grupo 1 (G1), submetidos a descorticação bilateral dos processos transversos; e vinte e quatro indivíduos no grupo 2 (G2), que receberam 2g de autoenxerto da crista ilíaca sobre a área de descorticação. Três coelhos do G1 e oito do G2 foram submetidos à eutanásia as cinco, sete e nove semanas após o ato operatório e à avaliações por palpação, radiográfica e histológica no local do procedimento. Testes biomecânicos para avaliação de força e rigidez da união foram realizados somente nos animais do G2 e as vértebras adjacentes não operadas, serviram de controle. Os animais do G1 apresentaram mobilidade normal à palpação do segmento operado em todos os momentos de avaliação e não apresentaram evidência radiográfica de união. Na avaliação histológica foi observada discreta reação periosteal, sem evidências de formação de ponte óssea. No G2, as avaliações por palpação e radiográficas evidenciaram indícios de união óssea as cinco semanas, intensificando-se ao longo das semanas de avaliação. Na análise histológica foi observada reabsorção de fragmentos ósseos as cinco semanas, predominância de trabéculas ósseas e corações condróides, além de suprimento sanguíneo abundante as sete semanas e osteointegração em todo leito de enxertia as nove semanas, com predomínio de formação óssea endocondral. Os testes biomecânicos evidenciaram aumento da força e rigidez da massa óssea ao longo do tempo de avaliação. Quando foi realizada comparação das vértebras tratadas e não tratadas, os índices de união foram maiores em todos os momentos, no grupo tratado. Com os resultados foi possível concluir que alta percentagem de união vertebral foi conseguida quando o osso autógeno da crista ilíaca foi utilizado como material de enxertia em coelhos.

Finite-element analysis for lumbar interbody fusion under axial loading.

A parametric study was conducted to evaluate axial stiffness of the interbody fusion, compressive stress, and bulging in the endplate due to changes in the spacer position with/without fusion bone using an anatomically accurate and validated L2-L3 finite-element model exercised under physiological axial compression. The results show that the spacer plays an important role in initial stability for fusion, and high compressive force is predicted at the ventral endplate for the models with the spacer and fusion bone together. By varying the positioning of the spacer anteriorly along anteroposterior axis, no significant change in terms of axial stiffness, compressive stress, and bulging of the endplate are predicted for the implant model. The findings suggest that varying the spacer position in surgical situations does not affect the mechanical behavior of the lumbar spine after interbody fusion.

[Preliminary evaluation of the efficacy of transpedicular refilling of spongiosa loss with autologous grafts in thoraco-lumbar vertebral bodies using the Daniaux method]. / Wczesna ocena skutecznosci transpedikularnego wypelniania przeszczepami ubytków kosci gabczastej zlamanych trzonów kregów piersiowo-ledzwiowej czesci kregoslupa wg Daniaux.

In Orthopaedic University Clinic in Lublin there were 35 patients with thoraco-lumbar spine fractures since 1993 to 1997. In 18 operated patients fractures of vertebral bodies were reduced and bone loss refilled by autogenous morselised grafts implanted through arc's basis using Daniaux method. There were 9 L1 fractures, 6 Th12 and single one on levels of Th11, L2 and L3. Complete spinal cord injury had 5 patients and partial 13. The degree of vertebral body compression was counted using Taillard's formula preoperatively, 4 weeks, 6 and 12 months after surgery. The anterior wall of vertebral body was decline ranged from 20% to 77%, average 51.9%. There were evaluations of 7 patients 6 months from fixator removal. Presented results support the opinion that operative reconstruction of vertebral body's fracture with autologous spongiosa grafts implantation in place of bone loss gives better chance for anterior wall height reconstitution. Small loss of correction after metal fixator removal, average 7.7%, testify good graft's remodeling and sufficient durability of Daniaux's method of treatment.

1995 Volvo Award in basic sciences. The use of an osteoinductive growth factor for lumbar spinal fusion. Part I: Biology of spinal fusion.

STUDY DESIGN: The histology of lumbar intertransverse process spinal fusion was studied in an experimental model in rabbits. OBJECTIVES: To qualitatively and quantitatively analyze the sequential histology of spinal fusion using a previously validated animal model. SUMMARY OF BACKGROUND DATA: Few previous studies have described the sequential histology during the posterolateral spinal fusion healing process using autogenous bone, and a basic understanding of the biology of this repair process is lacking. METHODS: Fourteen adult New Zealand white rabbits underwent single-level posterolateral lumbar intertransverse process arthrodesis with autogenous iliac bone graft. Animals were killed 1-10 weeks after surgery, and the fusion masses were analyzed histologically and quantitated using a semiautomated image analysis system. RESULTS: Three distinct phases of healing were identified (inflammatory, reparative, and remodeling) and occurred in sequence but in a delayed fashion in the central zone of the fusion mass compared with the outer transverse process zones. Membraneous bone formation, evident first at the ends of the fusion eminating from the decorticated transverse processes, was the predominant mechanism of healing. The central zone was somewhat different in that there was a period of endochondral bone formation during weeks 3 and 4 in this zone where cartilage formed and was converted to bone. Remodeling in the central zone had equilibrated with the transverse process zones by 10 weeks. CONCLUSIONS: Lumbar intertransverse process spinal fusion is a complex process from a spatial and temporal standpoint. When autogenous bone is used as the graft material, this process critically depends on a variety of factors from the decorticated host bone and exposed marrow. The persistence of a central cartilage zone may be related to some types of nonunions and deserves future investigation. This enhanced understanding of the biology of spinal fusion with autogenous bone graft will provide a foundation for optimizing the use of osteoinductive bone growth factors in this healing process.

1995 Volvo Award in basic sciences. The use of an osteoinductive growth factor for lumbar spinal fusion. Part II: Study of dose, carrier, and species.

STUDY DESIGN: Efficacy of a bovine-derived osteoinductive growth factor was studied in a rabbit model and in a nonhuman primate model of posterolateral lumbar spinal fusion. OBJECTIVES: To determine the minimum effective dose of growth factor and the influence of different carrier material on the outcome of intertransverse process lumbar fusion. SUMMARY OF BACKGROUND DATA: Bone morphogenetic proteins and related growth factors are becoming increasingly available in purified extract or genetically engineered forms and are capable of inducing new bone formation in vivo. Osteoinductive growth factors to enhance lumbar spinal infusion have not been well studied in models of posterolateral intertransverse process fusion. Because of the diminished potential of bone regeneration in primates (including humans) compared with phylogenetically lower animals, extrapolations regarding dose and efficacy cannot be made directly from results obtained in experiments performed on phylogenetically lower animals. Experiments on non-human primates are a critical step before attempting to use these growth factors on humans. METHODS. One hundred fifteen adult New Zealand white rabbits and 10 adult rhesus macaques underwent single level posterolateral intertransverse process lumbar spinal arthrodesis to evaluate different doses and carrier materials for a bovine-derived osteoinductive bone protein extract. Rabbit fusion masses were evaluated 5 weeks after arthrodesis by manual palpation, radiography, biomechanical testing, and light microscopy. Monkey fusion masses were evaluated 12 weeks after arthrodesis by radiography and light microscopy. RESULTS: Successful posterolateral intertransverse process spinal fusions were achieved in the rabbit models using an osteoinductive growth factor with three different carriers (autogenous iliac bone, demineralized allogeneic bone matrix, and natural coral). There was a dose-dependent response to the osteoinductive growth factor in the rabbit model, indicating that a threshold must be overcome before bone formation is induced. The methodology for biologic enhancement of spinal fusion developed in the rabbit model transferred successfully to the rhesus monkey, where the use of the osteoinductive growth factor with a demineralized bone matrix carrier resulted in spinal fusion in 12 weeks. CONCLUSION: These experiments provide an essential building block in the understanding of the biology of spinal fusion and the use of osteoinductive growth factors to enhance a posterolateral intertransverse process spinal fusion. The achievement of posterolateral spinal fusion in the rhesus monkey using an osteoinductive growth factor is a significant step toward the biologic enhancement of spinal fusion in humans.

Intertransverse process lumbar arthrodesis with allogeneic fresh-frozen bone graft.

Nine patients were treated with ten intertransverse process lumbar spine anthrodeses using fresh-frozen crushed corticocancellous allogeneic bone as graft material. No instrumentation was used. The clinical and roentgenographic follow-up period ranged from one to three years. Seven procedures showed successful arthrodesis and three demonstrated pseudarthroses. Increased age and systemic disease were associated with an increased risk of pseudarthrosis. Persistent back pain was associated with pseudarthrosis. Compared with 58 patients treated with intertransverse process lumbar fusion with autogeneic iliac bone as graft material, the overall fusion rate is inferior: 70% versus 92%, respectively.

Lumbosacral fusion using internal fixation with a spinous process for the graft: a review of 50 patients with a five-year maximum follow-up.

During a 5 year period 50 patients with chronic low back pain, with or without sciatica due to a proven lumbosacral disk lesion, underwent a spinal fusion using the Boucher method of screw fixation of the facet joints. The L-4 spinous process was excised and fashioned into an H-shape to act as the bone graft between the spinous processes so avoiding an iliac crest incision. Thus blood loss and operating time were substantially diminished. The screws maintain fixation for an 8-week period during which time the graft is "taking." Being inserted with spinous processes distracted about 1 cm the screws and the graft take the load off the painful posterior part of the annulus, and in addition, the distraction of the spinous processes enlarges the intervertebral foramina by about 1 cm thus making subsequent foraminal stenosis unlikely. Loosening of the screws after incorporation of the graft was observed in some cases, but was not considered to be clinically significant. Spinal fusion using screws for internal fixation including indications and contraindications requires careful consideration of operative technique, postoperative management and complications. The clinical evolution of 86% of the patients was rated good or fair from a clinical standpoint; 86% showed a fusion; 14% demonstrated a pseudarthrosis. Three of the 7 pseudarthrotic patients had a good clinical result. The other 4 had only a fair clinical result. Nine of the 14 patients with fair clinical results had a fusion radiologically; all 7 of the clinically unimproved had a fusion. Since the graft is placed at least 1 cm dorsal to the laminae, spinal cancal stenosis is extremely unlikely.