[Bone tissue engineering. Reconstruction of critical sized segmental bone defects in the ovine tibia]. / Knochen-Tissue-Engineering. Rekonstruktion segmentaler Knochendefekte kritischer Größe in der Schafstibia.

Well-established therapies for bone defects are restricted to bone grafts which face significant disadvantages (limited availability, donor site morbidity, insufficient integration). Therefore, the objective was to develop an alternative approach investigating the regenerative potential of medical grade polycaprolactone-tricalcium phosphate (mPCL-TCP) and silk-hydroxyapatite (silk-HA) scaffolds.Critical sized ovine tibial defects were created and stabilized. Defects were left untreated, reconstructed with autologous bone grafts (ABG) and mPCL-TCP or silk-HA scaffolds. Animals were observed for 12 weeks. X-ray analysis, torsion testing and quantitative computed tomography (CT) analyses were performed. Radiological analysis confirmed the critical nature of the defects. Full defect bridging occurred in the autograft and partial bridging in the mPCL-TCP group. Only little bone formation was observed with silk-HA scaffolds. Biomechanical testing revealed a higher torsional moment/stiffness (p < 0.05) and CT analysis a significantly higher amount of bone formation for the ABG group when compared to the silk-HA group. No significant difference was determined between the ABG and mPCL-TCP groups. The results of this study suggest that mPCL-TCP scaffolds combined can serve as an alternative to autologous bone grafting in long bone defect regeneration. The combination of mPCL-TCP with osteogenic cells or growth factors represents an attractive means to further enhance bone formation.

Effect of hospital and surgeon volume on patient outcomes following treatment of abdominal aortic aneurysms: a systematic review.

OBJECTIVES: This systematic review assessed the efficacy of centralisation for the treatment of unruptured and ruptured abdominal aortic aneurysms. Patient outcomes achieved by low and high volume hospitals/surgeons, including morbidity, mortality and length of hospital stay, were used as proxy measures of efficacy. DESIGN: Systematic review was designed to identify, assess and report on peer-reviewed articles reporting outcomes from unruptured and ruptured abdominal aortic aneurysms. No language restriction was placed on the databases searched. MATERIALS: Only peer-reviewed journals articles were included. METHODS: To ensure the contemporary nature of this review, only studies published between January 1997 and June 2007 were sought. Studies were included if they reported on at least one volume type and patient outcome. RESULTS: Twenty two studies were included in this review. In the majority of group assessments, the number of studies reporting statistical significance was similar to the number of studies reporting no statistical significance. CONCLUSION: The paucity of studies reporting statistically significant results demonstrates that although this evidence exists, its potential to be overstated must also be taken into account when drawing conclusions as to its efficacy for twenty first century healthcare systems.

Vascularised free fibular flap in bone resection and reconstruction.

This paper compares allograft alone and in combination with vascularised free fibular flaps (FFF) to reconstruct long bone defects after tumour excision. We present 33 cases, 21 of these patients had reconstruction with an allograft alone as the initial procedure. Nine patients underwent reconstruction with FFF plus allograft plus iliac crest bone graft (ICG), two patients underwent reconstruction with a FFF and ICG and one patient underwent reconstruction with an allograft, a pedicled fibular flap and a FFF. The allograft was obtained from the Queensland Bone Bank and had been irradiated to 25 000Gy. In our experience (N=21) the complication rates with allograft alone were: delayed union 3, nonunion 7, fractured allograft 6, infection requiring resection of the allograft 3, other infections 2. The revision rate was 48% (10 cases of which five required a free fibular flap) and an average of 1.8 revision procedures were required. In the lower limb cases, the mean time to full weightbearing was 20 months and 40% were full weightbearing at 18 months. We felt that the high complication rate compared with other series may have been related to the irradiation of the graft. FFFs were used in 18 cases, 12 cases were primary reconstructions and six were revision reconstructions. The mean fibular length was 19.4 cm (range 10-29 cm). There were no flap losses and the FFF united at both ends of 11 of 12 primary reconstruction cases. One case had nonunion at one end, giving a union rate of 96% (23 of 24 junctions). When a FFF was used in combination with an allograft as a primary reconstruction, the allograft nonunion rate was 50% (five of 10 cases). The mean time to full weightbearing in the lower limb cases was 7.5 months and 100% were full weightbearing at 18 months. The FFF hastens time to full weightbearing but does not appear to affect the complication rates of allograft. The number of revision procedures required is reduced in the presence of a FFF and is the latter is a useful technique for the salvage of refractory cases.

Giant cell tumor of bone.

Giant cell tumor of bone is an unusual neoplasm and treatment commonly leads to local recurrence. This can be related to the aggressiveness of the tumor or to the incompleteness of its removal. This study includes 27 cases that presented to our institution between the 1984 and 1994. One case was as a consultation only and 9 cases, either Campanacci Grade 3 or patients with considerable joint destruction, were treated by resection and reconstruction. One case was treated by curettage and cementation. Sixteen cases were treated with a combination of radical curettage, high speed burring, pulsatile lavage, and bone graft (either autograft or allograft mixed with autograft). No other adjuvant therapy was used. All of these 16 cases had a minimum follow-up of 5 years and none had a local recurrence. This study demonstrates that local control of giant cell tumors can be obtained by appropriate staging, resection of aggressive tumors, and by conservative management of the others. Such conservative management provides a bony matrix for the subchondral bone that is preferable to other treatments that have become popular in recent years, including cementation. This should provide better joint function in the longer term. High local recurrence rates have been reported in other series, but by a combination of appropriate selection of cases and by careful treatment of the Campanacci Grade 1 and 2 cases, these patients can have an uncomplicated outcome.

Malignant sacrococcygeal germ cell tumour in an adult.

In adults, malignant sacrococcygeal germ cell tumour is a rare cause for a presacral tumour, with only 17 cases having been reported in the literature since 1907. We report the case of a 34 year old male who presented with a 6 month history of symptoms relating to a malignant presacral tumour which required en bloc excision including the lower sacrum and rectum. He died with lung and mediastinal metastasis 7 months following surgical excision and adjuvant chemotherapy using Cisplatin, Bleomycin and Etoposide. Prior to his death, he had a severe polyarthritis of his peripheral joints and evidence of hypertrophic osteo-arthropathy. The literature indicates that adults with these tumours have a poor prognosis, with only one reported long-term survivor. Surgical excision offers the only chance of cure, with the role of adjuvant therapy not having been defined because of the small numbers.

A nonbacterial cause of post-traumatic soft-tissue gas.

A young male sustained a wound on the lateral aspect of the right thigh, presenting 24 hours later with subcutaneous crepitus over the thigh. He was systemically well, Gram stains and wound culture were negative. The cause was a sucking wound due to the valvelike action of the iliotibial band.