The prosthesis anchored to the vertebral body by a large central keel has inherent risk of angular mismatching between vertebral endplate and prosthesis endplate at large lordotic segment such as L5-S1. Theoretically, these angular mismatching can be considered to cause several problems such as segmental hyperlordosis, anterior positioning of upper prosthesis, posterior prosthetic edge subsidence, decreased ROM and poor clinical outcome. The purpose of this study is to assess whether angular mismatching between vertebral endplate and prosthesis endplate in lumbar total disc replacement (L-TDR) with ProDisc-L influence on radiological and clinical outcomes.

We evaluated 64 levels of 56 patients who were implanted with ProDisc-L from 2002 to 2006. Prosthetic levels were 38 levels of L4–5, and 26 levels of L5-S1 (8 patients had 2 level-operations of L4–5 and L5-S1). Mean follow-up was 25.6 (12–49) months. Angle of mismatching between lower endplate of upper vertebral body and upper prosthetic plate, segmental flexion/extension ROM, segmental lordosis angle at extension, distance from the posterior wall of vertebral body to posterior prosthetic edge were measured in the radiographs. Clinically VAS and ODI were evaluated. Angular mismatching between upper vertebra and prosthesis of L4–5 and L5-S1 was 1.6° (range, 0–6°) and 5.6° (0–13°) (p< 0.001) respectively, at final follow-up. Angular mismatching at immediate postoperative radiographs (2.3° in L4–5 and 4.9° in L5-S1) and at final follow-up was not significantly different (p=0.324 in L4–5, 0.620 in L5-S1). Mean segmental ROM of operated levels was 10.6° (4–22°) in L4–5 and 6.1° (2–13°) in L5-S1(p< 0.001). Mean segmental ROM, mean segmental lordosis angle, and mean distance from posterior margin of vertebral body to posterior end of prosthesis in L5-S1 were 6.8° (4–13°), 12.8° (8–17°), 3.8mm (1–6mm) in cases with angular mismatching less than 10°, and 4.6° (2–7°), 21.3° (19–25°), 6.0 mm (2–8mm) in that of 10° or more (p=0.024, < 0.001, 0.039), respectively. In L4–5 angular mismatching of more than 5° were only 2 cases without statistical significance. Clinical outcomes, VAS and ODI, of L4–5 compared with that of L5-S1 and of angular mismatching less than 10° with that of 10° or more in L5-S1 did not have difference between them (p> 0.05). Angular mismatching between lower endplate of upper vertebra with upper prosthesis endplate is more common in L5-S1 than in L4–5. L-TDR at the most lordotic level, L5-S1, implantation of upper prosthesis with mismatched angle seems to be the causes of lessened segmental ROM, increased segmental lordosis, and anterior positioning of prosthesis.

Extensive bone deficiencies in proximal femur remains a significant challenge in hip surgery. In such a situation, one alternative is to use a proximal femoral allograft-prosthesis composite (APC) to restore the mechanical integrity and bone stock. The current study was performed to analyze the results of APC in the treatment of femoral bone deficiency.

From January 1996 to June 2006, 12 patients who received 15 APC (3 of them received repeated APC), were followed for a mean of 4.2 years (range 2.0 to 9.8 years) by one surgeon. 5 were males and 7 were females and the mean age of the patients was 60.9 years (range 32 to 84 years). 6 patients were diagnosed with septic loosening, 5 were with aseptic loosening, 4 were with re-revision arthroplasty, and 1 was with limb salvage procedure due to malignancy and all were treated with fresh-frozen allograft. The surgical technique was used to cement the femoral component into the allograft but not into the host bone except 1 case.

The average Harris hip score improved from 21.8, preoperatively, to 83.2, the latest follow-up, and the all stems showed good stability except 3 cases of aseptic loosening. These 3 cases went through a repeated operation with another APC after mean 83.7 months (51,92,108 months) and their results showed good stability. 11 APC had a good junctional union. One case was showed junctional nonunion that needed onlay graft at 3.3 years after APC. There were no infections (or septic loosening), dislocations and allogragt fractures (except one great trochanter avulsion fracture, neither clinical symptoms nor went a surgical treatment).

This study demonstrated that the use of APC for extensive proximal femoral bone deficiencies showed a clinically, functionally and radiologically good results. Therefore it is considered as a good options.

Anterior decompression and fusion has been standard treatment for cervical disc herniation and myelopathy with disc degeneration. Since cervical total disc replacement (TDR) has been introduced with early favorable results and ideal mechanism, it has gained its popularity recently. But varying degrees of heterotopic ossification (HO) around the operated segment have been noted in the literatures. The theoretical advantages of TDR are the maintenance of intervertebral motion and prevention of adjacent segment degeneration. It is questionable that if HO occurs after TDR, mobility of operated segments would be restricted then clinical outcome worse. Purpose of this study is to determine prevalence of HO and to investigate that the presence of HO would limit motion and subsequently negatively affect clinical outcome following cervical TDR.

We analyzed 29 patients (30 levels) who were treated with cervical TDR by 2 spine specialists using 4 types of prostheses (Mobi-C: 13 levels, ProDisc: 10, Bryan: 5, Prestige LP: 2) consecutively from July 2004 to June 2007. Postoperative mean follow-up period was 21.4 (12–36) months. We assessed presence of HO and segmental ROM radiographically and clinical outcome by VAS, ODI after 1.5, 3, 6 months, and every year postoperatively in principle. All subjects were divided by 3, which were group A (no HO, McAfee class 0), group B (class I and II), and group C (class III and IV), then compared with each other.

HO was detected on 14 levels (46.7%) in the 30 levels after at mean of 8.2 (4–18) months after operation. There were 15 levels(53.3%) of group A (no HO, class 0), 7 levels of group B (class I HO:3, II: 4), and 7 levels of group C (class III: 3, IV: 4). Segmental flexion-extension ROM of group A was 10.1 (5.6–16.2)°, group B is 8.3 (3.5–14.4)°, and group C is 3.1 (0.0–6.6)° (p< 0.001, multiple comparison test with post hoc Bonferroni correction). And no difference in the clinical outcomes, VAS and ODI, was found compared with each other among group A, B, and C (p> 0.05).

Nonetheless, longer term follow-up should be performed to investigate whether clinical outcomes would be changed and occur adjacent level degeneration as time goes on. In addition, further study for prevention of HO may be needed as in HO of other joint replacement surgery not to lose superior mechanism to fusion treatment.

Introduction Bone morphogenetic protein-7 (BMP-7) is known to stimulate both cellular proliferation and extracellular matrix synthesis in the intervertebral disc but its protective role in apoptosis is unknown. The aim of this study was to determine whether BMP-7 protect cultured intervertebral disc cells following stimulation of apoptosis.

Methods Nucleus pulposus tissues were obtained from consent individuals under surgical procedures and digested with collagenase prior to culturing. Cellular apoptosis was achieved by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide (H2O2) incubation. BMP-7 (Stryker) was used at 100ng/ml, 5 hours prior to the addition of apoptotic stimulation. Cellular apoptosis was detected by TUNEL assay, caspase-3 activity and caspase-3 protein expression. Cellular proliferation and viability was assayed by H3-thymidine incorporation and MTS assay respectively. Collagen II and aggrecan protein levels were measured using western blots and immunostaining. Proteoglycan synthesis was determined by (35)S-sulfate incorporation method. Nitric oxide and alkaline phosphatase activity were measured.

Results Both extrinsic and intrinsic apoptotic pathways were induced by TNF-β or hydrogen peroxide with increased proteolytic activity of caspase-3 as well as cellular shrinkage and nuclear condensation. Addition of BMP-7 prior to stimulation of apoptosis resulted in complete block of the apoptotic effects of both inducers as well as the cellular nitric oxide induced by TNF-β and BMP-7 increases cellular viability, proliferation and extracellular matrix production in an apoptotic environment with no osteoblastic activity induction of discal cells.

Discussion BMP-7 prevents apoptosis of cultured human disc cells induced by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide. Induction of apoptosis led to down regulation of extracellular matrix proteins, decreased cell viability, morphological changes and activation of caspase-3, however addition of BMP-7 alone prevented the effects observed. One possible mechanism of the anti-apoptotic effects of BMP-7 was shown by its retardation of the elevated levels of TNF-β induced nitric oxide.

Introduction Intervertebral disc degeneration may cause chronic low back pain. Disc degeneration is characterized by dysfunctional cells and a decrease in extra-cellular components. Bone marrow derived mononuclear cells are a heterogeneous cell population which contains mesenchymal stem cells. Transplantation of stem cells and progenitor cells may provide a new approach to treat disc degeneration, but it is unclear if transplanted cells can survive and differentiate in the non-vascularized disc.

Methods Bone marrow was collected from syngeneic Sprague-Dawley rats and mononuclear cells were isolated. The cells were labelled with a fluorescence dye (Cell Tracker Orange) and suspended in PBS. 10–20μl of the cell suspension (1–2x10⁵ cells/disc) was transplanted into coccygeal discs in 12 syngeneic rats. For each rat two discs were cell transplanted and one disc served as control. The rats were sacrificed after 0, 7, 14 or 21 days. For each time point the discs from one animal were saved for routine histological staining. The cell transplanted discs of the other animals (n=4 discs per time point) were formalin-fixed, frozen and sectioned together with the control discs. Frozen disc sections were visualized with fluorescence microscopy and the number of transplanted cells assessed. Expression of collagen II, a marker of chondrocytes and chondrocyte-like cells in the disc, was assessed in the transplanted cells using immunofluorescence technique.

Results All cell-suspension injected discs contained transplanted bone-marrow cells. The discs within each time-group demonstrated a large variation in number of detected cells. There was a decrease in detected cells at 7, 14 and 21 days compared to day 0. Transplanted cells expressed collagen II after 21 days but not after 7 and 14 days.

Discussion The results suggest that transplanted bone marrow-derived mononuclear cells can survive and differentiate within the intervertebral disc. Further studies in models of disc degeneration are warranted to investigate the regenerative potential of the disc following cell transplantation.