Splint sterilization--a potential registration hazard in computer-assisted surgery.

PURPOSE: Registration of preoperative targeting information for the intraoperative situation is a crucial step in computer-assisted surgical interventions. Point-to-point registration using acrylic splints is among the most frequently used procedures. There are, however, no generally accepted recommendations for sterilization of the splint. An appropriate method for the thermolabile splint would be hydrogen peroxide-based plasma sterilization. This study evaluated the potential deformation of the splint undergoing such sterilization. Deformation was quantified using image-processing methods applied to computed tomographic (CT) volumes before and after sterilization. MATERIALS AND METHODS: An acrylic navigation splint was used as the study object. Eight metallic markers placed in the splint were used for registration. Six steel spheres in the mouthpiece were used as targets. Two CT volumes of the splint were acquired before and after 5 sterilization cycles using a hydrogen peroxide sterilizer. Point-to-point registration was applied, and fiducial and target registration errors were computed. Surfaces were extracted from CT scans and Hausdorff distances were derived. Effectiveness of sterilization was determined using Geobacillus stearothermophilus. RESULTS: Fiducial-based registration of CT scans before and after sterilization resulted in a mean fiducial registration error of 0.74 mm; the target registration error in the mouthpiece was 0.15 mm. The Hausdorff distance, describing the maximal deformation of the splint, was 2.51 mm. Ninety percent of point-surface distances were shorter than 0.61 mm, and 95% were shorter than 0.73 mm. No bacterial growth was found after the sterilization process. CONCLUSION: Hydrogen peroxide-based low-temperature plasma sterilization does not deform the splint, which is the base for correct computer-navigated surgery.

Treatment and outcome of parosteal osteosarcoma: biological versus endoprosthetic reconstruction.

BACKGROUND AND OBJECTIVES: Due to its good prognosis despite local recurrence, more and less invasive methods for surgical treatment of parosteal osteosarcoma (POS) have been described. Aim of this retrospective single-center study was to investigate differences in outcome after biological and prosthetic reconstruction. METHODS: A total of 28 patients with POS, 14 females, 14 males, mean age of 27 years (median, 24 years; range 15-59 years), mean follow-up of 130 months (median, 104 months; range, 9-383 months), underwent wide tumor resection and prosthetic reconstruction (12 patients, 42.9%), less extensive resection and biological reconstruction (11 patients, 39.3%), rotationplasty (three patients, 10.7%), or amputation (two patients, 7.1%). RESULTS: There were two cases of local recurrence in patients with biological reconstruction and three cases of pulmonary metastases, leading to death of disease in two. Ten-year disease-specific survival was 91.1%. There was no significant difference between prosthetic and biological reconstruction in terms of local recurrence, metastasis, or functional outcome (mean MSTS Score, 85%). There were significantly more revisions in prosthetic reconstructions. CONCLUSIONS: Given that the resection of the tumor has clear margins, both prosthetic and biological reconstruction show similar results; prostheses allow better local tumor control, however, require more revisions over time.

Microarray analysis identifies distinct gene expression profiles associated with histological subtype in human osteosarcoma.

Osteosarcoma is the most common primary malignant bone tumour. Currently osteosarcoma classification is based on histological appearance. It was the aim of this study to use a more systematic approach to osteosarcoma classification based on gene expression analysis and to identify subtype specific differentially expressed genes. We analysed the global gene expression profiles of ten osteosarcoma samples using Affymetrix U133A arrays (five osteoblastic and five non-osteoblastic osteosarcoma patients). Differential gene expression analysis yielded 75 genes up-regulated and 97 genes down-regulated in osteoblastic versus non-osteoblastic osteosarcoma samples, respectively. These included genes involved in cell growth, chemotherapy resistance, angiogenesis, steroid- and neuropeptide hormone receptor activity, acute-phase response and serotonin receptor activity and members of the Wnt/ß-catenin pathway and many others. Furthermore, we validated the highly differential expression of six genes including angiopoietin 1, IGFBP3, ferredoxin 1, BMP, decorin, and fibulin 1 in osteoblastic osteosarcoma relative to non-osteoblastic osteosarcoma. Our results show the utility of gene expression analysis to study osteosarcoma subtypes, and we identified several genes that may play a role as potential therapeutic targets in the future.

Different expression patterns of organic anion transporting polypeptides in osteosarcomas, bone metastases and aneurysmal bone cysts.

Organic anion transporting polypeptides (OATP) were identified as transmembrane transporters for various endo- and exogenous organic compounds (hormones, prostaglandins, anticancer drugs). OATP expression had been shown in different tissues, but not in bone tumors. Therefore, the expression pattern of all known eleven human OATPs was analyzed by quantitative RT-PCR in 21 human bone tumor specimens (osteosarcomas, bone metastases and benign aneurysmal bone cysts). Transcriptional expression of OATP1A2, 1C1, 2A1, 2B1, 3A1, 4A1, 4C1 and 5A1, but not of OATP1B1, 1B3 and 6A1 was observed in malignant and non-malignant tumor specimens at varying level. Importantly, OATP3A1, 4A1, 2B1 and 1C1 mRNA levels were significantly higher in aneurysmal bone cysts as compared to osteosarcomas. Elevated mRNA levels of OATP2A1, 1A2, and 4C1 in metastases from kidney cancer and of OATP5A1 in prostate cancer suggest that the OATP expression pattern in metastases is comparable to that of the primary tumors. Different to tissue, OATP expression in osteosarcoma cell lines HOS and MG-63, normal human osteoblast outgrowth cells (hOB) and bone marrow stromal cells (BMSC) is limited to OATP3A1 and OATP4A1. High OATP expression levels, particularly in benign bone tumors, suggest an important role of these transporters for providing hormones, their conjugates, prostaglandins and drugs in bone cells. Thereby, they may influence bone resorption and formation.

Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans.

BACKGROUND: Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans. METHODS: Twelve volunteers applied three hand-rubs containing 95% (hand-rub A), 85% (hand-rub B) and 55% ethanol (hand-rub C; all w/w). For hygienic hand disinfection, 4 mL were applied 20 times for 30 s, with 1 minute break between applications. For surgical hand disinfection, 20 mL of each hand rub was applied to hands and arms up to the level of the elbow 10 times for 3 minutes, with a break of 5 minutes between applications. Blood concentrations of ethanol and acetaldehyde were determined immediately prior and up to 90 minutes after application using head space gas chromatography. RESULTS: The median of absorbed ethanol after hygienic hand disinfection was 1365 mg (A), 630 mg (B), and 358 mg (C). The proportion of absorbed ethanol was 2.3% (A), 1.1% (B), and 0.9% (C). After surgical hand disinfection, the median of absorbed ethanol was 1067 mg (A), 1542 mg (B), and 477 mg (C). The proportion of absorbed ethanol was 0.7% (A), 1.1% (B), and 0.5% (C). The highest median acetaldehyde concentration after 20 hygienic hand disinfections was 0.57 mg/L (hand-rub C, after 30 min), after 10 surgical hand disinfections 3.99 mg/L (hand-rub A, after 20 minutes). CONCLUSION: The overall dermal and pulmonary absorption of ethanol was below toxic levels in humans and allows the conclusion that the use of the evaluated ethanol-based hand-rubs is safe.

Expression of the melatonin receptor (MT) 1 in benign and malignant human bone tumors.

The beneficial effects of melatonin on bone homeostasis have been shown in various diseases. As this indoleamine causes dose-dependent modulation of bone-forming osteoblast and bone-resorbing osteoclast activities by receptor-independent and -dependent pathways, we investigated the expression of G-protein-coupled melatonin receptors (MTs) in malignant and non-malignant human bone lesions. By TaqMan polymerase chain reaction (PCR), we analyzed 30 specimens from osteosarcoma and 11 from benign bone tumors for MT1-mRNA expression. Furthermore, we determined mRNA expression levels of the osteoclast activity-stimulating receptor activator of nuclear factor-kappa B ligand (RANKL) and its counterpart osteoprotegerin (OPG). Although mean MT1-mRNA levels were similar (P = 0.596) in malignant (4.39 +/- 4.98-fold) and benign samples (4.64 +/- 6.81-fold), the highest MT1-mRNA levels (up to 27-fold) were observed in individual osteosarcomas, particularly, in two specimens of patients with local recurrence of the tumor. Moreover, mean RANKL- and OPG-mRNA levels were similar in malignant and benign specimens (RANKL: 7.38 +/- 9.61-fold versus 3.57 +/- 3.11-fold, P = 0.207; OPG: 23.45 +/- 32.76 versus 8.07 +/- 7.23-fold, P = 0.133). Again, highest RANKL- and OPG-mRNA levels (up to 41- and 160-fold, respectively) were observed in individual osteosarcomas. Expression of MT1-mRNA was confirmed in two human osteosarcoma cell lines (HOS, MG63). High expression levels of MT1-mRNA together with low OPG-mRNA were found in both osteosarcoma cell lines, while in normal human osteoblasts and bone marrow stromal cells, high OPG-mRNA levels were associated with low MT1-mRNA levels. These data on the abundant expression of MT1-mRNA in human bone tumors and osteosarcoma cells lines suggest an important role for MT1 in bone pathology.

Metatarsal reconstruction with use of free vascularized osteomyocutaneous fibular grafts following resection of malignant tumors of the midfoot. A series of six cases.

BACKGROUND: Bone and soft-tissue sarcomas are uncommon, and their location in the foot is extremely rare. While limb salvage has become the standard of care in the treatment of sarcoma in an extremity, the unique anatomy of the foot presents challenges in reconstructing a viable and functional limb. METHODS: Between 1998 and 2005, we used free microvascularized osteomyocutaneous fibular grafts to reconstruct the defects created after extensive midfoot resection in six consecutive patients with a primary malignant tumor. In all but one patient, the extent of the resection involved at least two metatarsals. The mean age (and standard deviation) at the time of the operation was 30+/-13 years. At the final follow-up examination, clinical and radiographic evaluations were performed on all patients, and functional outcome and quality of life were assessed with use of the Musculoskeletal Tumor Society score, the American Orthopaedic Foot and Ankle Society Score, and the Toronto Extremity Salvage Score. RESULTS: The median duration of follow-up was 52.2 months. Limb salvage was achieved in five patients. In the remaining patient, amputation was necessary because of flap failure. Revision surgery was necessary in all patients because of complications (skin ulcerations in three patients; hematoma in two patients; and infection, necrosis of the second toe, and flap necrosis in one patient each). At the time of final follow-up, five patients had satisfactory function and reported good quality of life. The average Musculoskeletal Tumor Society, American Orthopaedic Foot and Ankle Society, and Toronto Extremity Salvage scores were 82%, 75 points, and 92%, respectively. At the time of the final follow-up, five patients had no evidence of disease and one patient had disease. CONCLUSIONS: Following the resection of a malignant tumor in the midfoot, the use of microvascularized osteomyocutaneous fibular grafts has proven to be a successful surgical technique, offering an alternative to ablative surgery with functional restoration of the salvaged limb.

Estrogen sulfotransferase (SULT1E1) expression in benign and malignant human bone tumors.

BACKGROUND AND OBJECTIVES: 17beta-estradiol regulates growth and differentiation in normal and malignant bone. E2 is inactivated to 17beta-estradiol-sulfate through estrogen sulfotransferase (SULT1E1). RESULTS: In an explorative study, SULT1E1 mRNA expression was assessed in a broad range of samples from benign, primary and secondary malignant bone tumors. We detected SULT1E1 mRNA in 31/50 tumor samples (10/19 malignant, 6/13 benign tumors; 15/18 metastases). Significantly more SULT1E1-positive samples were found in metastases than in primary bone tumors (P = 0.019). Yet, there was no difference between malignant and benign primary tumors (P = 0.718). SULT1E1 mRNA levels were not related to patients' age, gender, tumor location, stage, grading, and chemotherapy pretreatment. Relative SULT1E1 mRNA levels did not correlate with that of estrogen-receptor alpha (ERalpha) as assessed by quantitative TaqMan PCR (10 malignant, 8 benign tissue samples). In the latter, ERalpha mRNA, but not SULT1E1 mRNA levels were significantly lower than in the malignant samples (P = 0.006 and P = 0.71, respectively). Also, pronounced expression of SULT1E1 mRNA but not of ERalpha mRNA was observed in osteosarcoma (MG-63, HOS) and Ewing's sarcoma (TC-71) cells, while human osteoblasts and BMSC contained ERalpha but not SULT1E1 mRNA. CONCLUSION: Frequent expression of SULT1E1 mRNA in various human bone tumors suggests that sulfonation might be important to control E2 levels and activity.

Expression of c-kit in human osteosarcoma and its relevance as a prognostic marker.

AIMS: To examine the prognostic relevance of c-kit expression in human osteosarcomas and to evaluate the mutation status in exon 9 and exon 11 of the c-kit gene. METHODS: c-kit expression was examined in 100 human osteosarcomas by immunohistochemistry using paraffin embedded tumour tissues, and capillary sequencing of genomic DNA was performed to search for mutations in exons 9 and 11 of the c-kit gene. RESULTS: 20 osteosarcomas showed c-kit expression ranging from 5% to 90% (mean 5.9%; SD 16.74%). Furthermore, DNA sequences of exon 9 and exon 11 of the c-kit gene were not altered in these tumours. Overall and disease free survival analysis did not reveal any differences between patients with osteosarcoma with c-kit expression and those with c-kit negative tumours. CONCLUSIONS: C-kit expression is not a prognostic marker in patients with osteosarcoma. The protein expression is not linked to mutations in exon 9 or exon 11 of the c-kit gene. Therefore, these exons may not function as targets for treatment modalities based on the suppression of c-kit tyrosine kinase activity.

Reconstructing the extensor apparatus with a new polyester ligament.

We analyzed the clinical outcome of patients who had reconstruction of the extensor apparatus with a new polyester ligament after extensive resection of malignant tumors around the knee. Twenty-two patients were included; 19 were evaluated after a mean followup of 44 months (range, 8-67 months) to assess active and passive knee range of motion, walking ability, need for revision, and TESS and Enneking scores. The patients were divided into two groups; patients in Group A had a weakened extensor mechanism and patients in Group B had a completely dissected extensor mechanism. Seven patients had excellent knee function with an extension lag less than 5 degrees. Five patients had an extension deficit less than 20 degrees, three patients had a deficit less than 40 degrees, and four patients could not extend their limb against gravity. However, all patients were able to walk without walking aids. They had a mean Enneking score of 83 points and a mean TESS score of 82 points. Patients who had distal femur resections had worse results than patients who had proximal tibia resections. The LARS ligament proved promising for augmentation and complete reconstruction of the extensor apparatus of the knee after extensive tumor resection, with excellent and good results in 59% of patients.

Characteristics of ovine articular chondrocytes in a three-dimensional matrix consisting of different crosslinked collagen.

The purpose of this study was to evaluate the (ultra-) morphology, biochemical behavior, and activity of ovine chondrocytes seeded on a matrix consisting of three types of collagen (I, II, III) with two different degrees of UV crosslinking. Ovine articular chondrocytes were isolated from stifle joints and seeded on both types of UV-crosslinked collagen matrices, as well as on non-crosslinked sponges, and cultured for 12 h, 7 days, 14 days, and 21 days. Histological analysis, electron microscopy, biochemical assays for glycosaminoglycans, and real-time quantitative PCR for collagens were performed for cell-seeded and unseeded matrices. There was no dramatic difference in the morphology and bioactivity of the cells; however, concerning handling characteristics and integrative stability, both types of crosslinked sponges were superior to non-crosslinked constructs. The results demonstrate that ovine articular chondrocytes express their phenotype in a sponge consisting of collagen; furthermore, because of mechanical reasons, non-crosslinked matrices cannot be recommended for implantation in vivo.

Trisacryl gelatin microspheres versus polyvinyl alcohol particles in the preoperative embolization of bone neoplasms.

The aim of this study was to compare the efficacy of trisacryl gelatin microspheres versus polyvinyl alcohol particles (PVA) in the preoperative embolization of bone neoplasms, on the basis of intraoperative blood loss quantified by the differences in preoperative and postoperative hematic levels of hemoglobin, hematocrit and erythrocytes count. From January 1997 to December 2002, preoperative embolization of bone tumors (either primary or secondary) was carried out in 49 patients (age range 12/78), 20 of whom were treated with trysacril gelatin microspheres (group A) and 29 with PVA particles (group B). The delay between embolization and surgery ranged from 1 to 13 days in group A and 1 to 4 days in group B. As used in international protocols, we considered hematic levels of hemoglobin, hematocrit and erythrocytes count for the measurement of intraoperative blood loss then the differences in pre- and postoperative levels were used as statistical comparative parameters. We compared the values of patients treated with embospheres (n = 10) and PVA (n = 18) alone, and patients treated with (group A = 10; group B = 11) versus patients treated without other additional embolic materials in each group (group A = 10; group B = 18). According to the Student's t-test ( p < 0.05), the difference of hematic parameters between patients treated by embospheres and PVA alone were significant; otherwise there was no significant difference between patients treated with only one embolic material (embospheres and PVA) versus those treated with other additional embolic agents in each group. The patients treated with microspheres had a minor quantification of intraoperative blood loss compared to those who received PVA particles. Furthermore, they had a minor increase of bleeding related to the delay time between embolization and surgery. The use of additional embolic material did not improve the efficacy of the procedure in either group of patients.

Chondrosarcoma of the hand: is a wide surgical resection necessary?

Chondrosarcomas of the hand are rare and generally treated with surgical resection. Thirteen patients with Grade 1 chondrosarcoma of the small bones of the hand were followed up for a mean of 99.8 months (range, 26-293 months). In eight patients (Group 1) curettage and reconstruction with cancellous bone was done and in five patients (Group 2) a wide resection was done. No patient experienced relapse in Group 2. In Group 1 one patient had a local relapse 18 months after intralesional resection. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed an average of 98% and 95% of the normal function in Groups 1 and 2, respectively. None of the patients had evidence of systemic spread of the disease. With a relapse rate of 12.5% and no distant metastases after curettage, intralesional resection is the preferred method of treatment in Grade 1 chondrosarcoma of the hand, allowing the patient to avoid amputation and major loss of function.