Complete Spontaneous Regression of Lung Metastases after Resection of CIC-Rearranged Sarcoma: A Case Report.

The vast majority of patients with soft tissue sarcomas (STS) of the trunk and bilateral lung metastases at diagnosis are considered incurable. These tumors have poor prognosis as only a palliative therapeutic approach can be offered to patients. We report on an extremely rare case in which bilateral lung metastases disappeared spontaneously following surgical resection of the primary CIC-rearranged sarcoma with no addition of chemotherapy or any other systemic therapy. A 53-year-old female presented with a rapidly swelling mass on her back. A magnetic resonance imaging scan of the chest revealed a large soft tissue mass on the posterior chest wall and bilateral lung metastases. Soon after stereotactic core-needle biopsy confirmation of round-cell sarcoma, the patient underwent surgery of the primary tumor as it started to be increasingly symptomatic. The resected specimen was pathologically diagnosed a poorly differentiated grade 3 sarcoma. Approximately 1 month later, a new CT scan revealed that the lung metastases were smaller and some of them had completely disappeared. Shortly afterward, the patient started adjuvant external beam radiotherapy of the tumor bed for 14 months. During the last follow-up visit, the patient confirmed no evidence of disease for 35 months postoperatively. In parallel, a histological study of pulmonary nodules, molecular analyses of the tumor, and a comprehensive study of the patient's immunophenotype were performed to gain some additional insights in the potential causes of this rare phenomenon.

Structural bone allograft fractures in oncological procedures.

PURPOSE: We report our experience analysing the risk of fracture amongst allografts in limb-preserving surgery for bone tumours. METHODS: We retrospectively reviewed our experience with bone allograft and its major complications when used for limb -preserving operations for bone tumours. Forty-one structural allografts were performed in 39 patients between 1992 and 2012. Minimum follow-up was 20 months. Massive allografts have a high complication rate. RESULTS: Excluding infection and nonunion, five acute fractures were found. All fractures occurred after the graft-host junction was united. Local factors-such as graft preservation, weight bearing, fixation to the host or systemic factors such as adjuvant treatments (chemotherapy or radiotherapy)-influence fracture rate. In our study, four patients achieved consolidation with internal fixation and autologous iliac-crest graft, whilst only one required graft exchange. DISCUSSION: There is no general consensus as to when to treat fractures using open reduction and internal fixation or by exchanging the allograft. Higher fracture rate in relation to systemic treatment was found. CONCLUSIONS: Massive structural allograft reconstruction still has a place in limb-preserving surgery, with an acceptable fracture rate and a durable solution.

In vivo tricalcium phosphate, bone morphogenetic protein and autologous bone marrow biomechanical enhancement in vertebral fractures in a porcine model.

PURPOSE: Minimally invasive techniques that introduce cement and bone substitutes inside the fractured vertebral body are a new treatment line with clinically proven efficacy. However, mechanical behaviours between different fillers throughout fracture evolution is yet to be clarified, as many substances are available for introduction into the vertebral body fracture. METHODS: We comparatively studied biomechanical properties of tricalcium phosphate, tricalcium phosphate with bone morphogenetic protein (rhBMP-7) and autologous bone marrow aspirate with rhBMP-7 in vivo to determine what substance is optimal for repairing vertebral lesions in a porcine model. This biomechanical study was carried out with an Instron-type testing machine. Data registered were necessary strength to reach vertebral fracture [Newtons (N)], shortening (millimeters) of the vertebra, energy absorption until vertebral fracture (Joules) and vertebral unit stiffness. RESULTS: For statistical study, we used the SPSS 16 package at a significance level of α = 0.05. In the presentation of the results, mean, standard deviation of mean, median and interquartile range (IQR) were analysed. Mean and standard deviation (SD) of strength in newtons (N) for the vertebral fracture are 756 N (SD = 253) in group 1, 1,500 N (SD = 1598) in group 2 and 1,230 N (SD = 1,598) in group 3. Stiffness after fracture was 229 N (SD = 123) in group 1, 277 N (SD = 135) in group 2 and 404 N (SD = 325) in group 3. CONCLUSIONS: The association of tricalcium phosphate and BMP-7 generates major vertebral resistance to external energy, the cause of such fractures. In such fractures, minor shortening occurs as soon as the vertebral body is fractured. Autologous bone marrow and BMP-7 provides increased biomechanical behavior, and the vertebral body is thus significantly strengthened.

Biomechanical assays for the study of the effects of hip prostheses: application to the reconstruction of bone defects with femoral allografts.

There is a need to study and validate the mechanical behavior of the bone-implant total hip prosthesis and the treatment of its complications with experimental studies due to the limitations showed by numerical methods. Epoxy resin replicas of a femur (stereolithography) and a mechanical validation were performed. We studied three cases: intact femur (Case 1); non-defective femur with non-cemented LD primary stem (Case 2); and femur with a cavitary defect, short cemented stem over an impacted allograft (Case 3). The test pieces were connected to 7 strain gauges. Three assays per piece were carried out with a vertical and oblique load (load-unload curves after a sequence between 0 and 145.9 N). We measured the k coefficient (distance from the natural state of the strains) and stability of the stem (flexion-compression by strain gauges 1, 2, 5, and 7 and transversal lengthening by strain gauges 3, 4, and 6). Results of the strain gauge analysis revealed linearity of results in all cases, and more so in load than in unload. Gauge 7 (proximal) revealed shortening in all cases. Gauges 2 and 5 provided qualitatively similar data due to a significant increase in rigidity. K coefficients were obtained with a nonsignificant difference when each of the test pieces was compared with Case 2. The results were reproducible in all 7 gauges. Observation of the load-unload curves in all the test pieces assayed shows that there are no variations in the pattern of behavior (when comparing the stability of a primary stem and a stem in the simulated reconstructed femoral defect. If these reconstructions are considered theoretically appropriate for giving primary stability to the stem--a sine qua non for the success of replacement surgery--then our study is novel.

Reconstruction of bone defects with impacted allograft in femoral stem revision surgery.

A retrospective clinical review was done on 54 revision hip patients. Radiological analysis examined the Gross and AAOS classifications, stem position, cement mantles, allograft and evolution (subsidence, resorption and remodelling). The Harris Hip score was used for clinical assessment. We used bone bank allograft and a polished non-collared stem LD. The follow-up period was 60.5 months (19.4-152.4), and the average age 68.5 (range: 22-85). There were 21 females and 33 males. The surgical approach was: lateral (5.56%) posterior (91.4%); trochanteric osteotomy: 25.9%; associated acetabular revision: 59.3%; previous operations: 1.9. The preoperative Harris score was 35 (28-40) and rose to 81 (50-99) postoperatively. The stem alignment was neutral (44.44%), varus (38.89%) and valgus (16.67%). The femur/stem diameter relationship was 1.8 (1.2-2.7). There were no changes in stem alignment in 94.4%. An adequate cement mantle was: proximal zone (61.1%), medium zone (27.8%) and distal zone (16.7%). The rate of any subsidence was 38.9% (progressive: 12.96%). The rate of complications was 40.7% and included periprosthetic fracture: 14.8%; superficial infection: 1.9%; deep late infection: 1.9%; dislocation: 3.7%; heterotopic ossification: 13%. The rate of new stem revision was 16.6%. The clinical and radiological success rate was 77.78%. A greater incidence of revisions has been found in stem malalignment, progressive subsidence, a Harris increase of <20 points, allograft resorption, small diameter stems and inadequate cement mantle. We recommend hard impaction and a cement mantle of at least 2 mm. Non-progressive subsidence does not increase stem loosening. The technique has been useful in recovering bone stock in a severely defective femur and achieves a stable reconstruction. The level of evidence was therapeutic study level III-2 (retrospective cohort study; see the instructions to the authors for a complete description of the levels of evidence).