Repair of long-bone pseudoarthrosis with autologous bone marrow mononuclear cells combined with allogenic bone graft.

BACKGROUND AIMS: Long-bone pseudoarthrosis is a major orthopedic concern because of numerous factors such as difficulty of the treatment, high recurrence, high costs and the devastating effects on the patients' quality of life, which sometimes ends in amputation. Although the "gold standard" for the treatment of this pathology is autologous bone grafting, which has high osteogenic, osteoconductive and osteoinductive properties, this treatment presents some restrictions such as the limited amount of bone that can be taken from the patient and donor site morbidity. Bone marrow mononuclear cells (BM-MNCs) comprise progenitor and stem cells with pro-angiogenic and pro-osteogenic properties. Allogenic cancellous bone graft is a natural and biodegradable osteoconductive and osteoinductive scaffold. Combination of these two components could mimic the advantages of autologous bone grafting while avoiding its main limitations. METHODS: Long-bone pseudoarthrosis was treated in seven patients with autologous BM-MNCs from iliac crest combined with frozen allogenic cancellous bone graft obtained from the tissue bank. RESULTS: All patients showed complete bone consolidation 5.3 ± 0.9 months (range, 2-9 months) after cell transplantation. Moreover, limb pain disappeared in all of them. The mean follow-up was 35.8 ± 4.6 months after transplantation (range, 24-51 months) without pseudoarthrosis recurrence or pain reappearing. CONCLUSIONS: Combination of autologous BM-MNCs and allogenic bone graft could constitute an easy, safe, inexpensive and efficacious attempt to treat long-bone pseudoarthrosis and non-union by reproducing the beneficial properties of autologous bone grafting while restricting its disadvantages.

Evaluation of Titanium Serum Levels in Patients After Spine Instrumentation: Comparison Between Posterolateral and 360º Spinal Fusion Surgery.

Introduction The use of orthopedic implants is a cause for concern for the release of its integrating metals and the systemic complications that may occur. Instrumented spine arthrodesis is the recommended treatment for many spine diseases. Different segmental fixation devices, commonly made of titanium and its alloys, are used in these surgeries. The use of this metal for spinal fusion has introduced the possibility of generating microscopic metal particles that are present in the tissues of the surrounding implants (peri-implant environment). In fact, metal debris has been found in the paraspinal soft tissues of patients with posterior lumbar instrumentation and showed to be particularly high in patients undergoing revision procedures of pseudoarthrosis. In addition, part of the metals might also dissolve (either from the released particles or directly from the implant surface) and circulate in the body fluids, accumulating (eventually) in remote organs. Material and methods A prospective study was designed with patients who were to be operated by the pathology of the lumbar spine to perform a vertebral arthrodesis composed of a titanium alloy (n=32). Two subgroups were differentiated according to the type of surgery performed: a) Posterolateral arthrodesis (N=5); b) Circumferential arthrodesis intervertebral implant of polyester-ether ketone (PEEK) (N=8) or titanium (N=19). The blood sample was taken before surgery and one year later. The samples were analyzed by mass spectrophotometry with a double focus inductive coupling plasma source (DF-ICP-MS). Results Blood titanium levels prior to surgery were similar to those in other publications (0.7449 micrograms per liter-1 (µgL-1), Standard Deviation (SD)=0.562). The average titanium concentration levels found after surgery was 2.5406 µgL-1 (SD=3,69), near 3.5-fold increase. After surgery, there was a significant mean increase in serum titanium levels of 1.7957 µgL-1 (SD=3.5765, Range=-0.57 µgL-1; 14.60 µgL-1). There is a statistically significant increment (p=0.00049) of the titanium concentration in the serum of the patients after surgery. If we analyze the patients in three groups according to the type of implants used (posterolateral, circumferential with PEEK, and circumferential with titanium), there are no differences between those who did not have an intersomatic device implanted and those in which PEEK implants were implanted, but with those in which it was titanium it was p=0.006 and p=0.018, respectively. Conclusions Patients undergoing vertebral instrumentation experience a significant increase in serum titanium levels compared to before surgery levels. The use of an intersomatic device did not show differences in titanium release with not using it when it was PEEK. There are significant differences between patients without intersomatic implants or those who had a PEEK implant with those in whom it was titanium, with a significant increase in blood titanium levels.