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Can steel screws be combined with titanium plates?
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Abstracts from international literature Fine-needle aspiration biopsy of salivary glands M. A. Smith Frable, W. J. Frable Laryngoscope 1991: 101:245-9
Between 1 January 1973, and 31 December 1988, the authors or their associates performed 552 fine-needle aspiration biopsies on patients with clinically significant masses of the salivary glands. All patients presented at the Medical College of Virginia Hospitals or Clinics of Virginia Commonwealth University; they were followed for periods ranging from 1 t o 16 years. When available, the fine-needle aspiration diagnoses were correlated with histologic diagnoses and long-term patient outcomes. The sensitivity for a neoplasm was 93.3%; the specificity for the absence of a neoplasm was 99%. Diagnostic efficiency was 96.4%, and predictive value of a positive aspiration for a neoplasm was 98.3%. With fine-needle aspiration, surgical excision of salivary gland masses is often unnecessary. In patients with primary and metastatic neoplasms involving the salivary glands, fine-needle aspiration aids the surgeon in mapping the extent of the surgical procedure and in preoperatively preparing the patient. The procedure is cost-effective. H. TIDEMAN
Sind Stahlschrauben mit Titanplatten kombinierbar? Can steel screws be combined with titanium plates? R. W~chter, E Stol[ Dtsch Z Mund Kiefer GesichtsChir 1991: 15: 275-84.
Both V4A-steel and titanium have distinct advantages when considering osteosynthesis plates and screws. In particular, V2A and V4A steel are characterized by good mechanical qualities, removability and low costs, while ti-
tanium shows excellent biocompatibility, and resistance against corrosion and elasticity. A combination of these 2 materials could, theoretically, be of advantage for use in osteosynthesis. This should only be allowed if it does not have a detrimental effect on the materials' characteristics. To find if this was so, the authors performed unilateral osteotomies of the mandible in 24 sheep, comparing osteosynthesis by using A0 titanium plates fixed with steel screws. For comparison, titanium screws were used in the end of the plate during the same procedure. Tissue reaction was evaluated histologically 6, 12 and 24 weeks after the osteosynthesis, using DONATH'S & BREUNER'S (1982) sawing/grinding method. Nineteen of 24 specimens could be evaluated. Microscopic examination showed no signs of corrosion. Histologically, as well as in electronmicroscopy studies of the interface area between the plates and steel screws, minimal signs of corrosion were found after 12-24 weeks. N o signs of further changes in the cell metabolism could be demonstrated. The authors conclude that at least for temporary osteosynthesis, a combination of steel screws with titanium plates of the kind used can be allowed. Further studies, including Atom Absorption Spectroscopy methods, may be necessary to study minimal corrosion effects on the surrounding vital tissues. R. REICH
Vaskularisierte por~se Kunststoffe als Ger(istmaterial f~ir pr~iformierte freie Lappen, Vascularized porous plastic materials as a framework for free flaps H. W. H~rl, M. KI6ppel, E. Biemer Handchir Mikrochir Plast Chir 1991: 23: 32-8.
To further improve the effects of reconstructive surgery, a means to support
and shape a free microvascular anastomosed flap is necessary. For example, this could be of advantage in the reconstruction of large bony and soft tissue defects in the skull area and could lead to less morbidity at the donor site. It is known that this can be done by free bone and cartilage transplants. Alloplastic materials could also serve this purpose if accepted in the recipient bed. The authors performed an experimental study on 54 Wistar rats, Three porous synthetic materials and silicon rubber were implanted as framework into an area which later was taken as a free flap. The implant blocks were 2 x 3 x 8 mm in each case. Proplast II (polytetrafluorethylene-aluminiumoxide) was compared to Medpor (porous, high density polyethylene), Porecon (porous, high density polyethylene) and Silastic. In each case, a superficial circumflex ilium artery pedicled groin flap was developed and the alloplastic material was implanted. Eighteen animals in each group were followed for 2, 4 and 6 weeks. MacroscopicaUy, there was no evidence of inflammatory reaction. A microangiographic study showed the development of a capillary network in the 3 porous materials already 2 weeks postoperatively. Histologically, the implantation of porous materials did not lead to a fibrous connective tissue capsule, as was found in the Silastic cases. The ingrowth rate of soft tissue into the materials was highest in M e @ o r which represents 50% pore-volume, the pores measuring 50-700/xm in diameter. In Proplast II, the ingrowth process was slower; however, 6 weeks after implantation, all porous materials showed an ingrowth rate of 100%. Proplast II, which represents a 70-90% pore-volume rate, showed a more distinct foreign reaction compared to the other porous materials. The clinical relevance of these findings is still unclear but this study can be considered as a step towards the development of new tedhniques. R. R~rcH
Abstracts from international literature Fine-needle aspiration biopsy of salivary glands M. A. Smith Frable, W. J. Frable Laryngoscope 1991: 101:245-9
Between 1 January 1973, and 31 December 1988, the authors or their associates performed 552 fine-needle aspiration biopsies on patients with clinically significant masses of the salivary glands. All patients presented at the Medical College of Virginia Hospitals or Clinics of Virginia Commonwealth University; they were followed for periods ranging from 1 t o 16 years. When available, the fine-needle aspiration diagnoses were correlated with histologic diagnoses and long-term patient outcomes. The sensitivity for a neoplasm was 93.3%; the specificity for the absence of a neoplasm was 99%. Diagnostic efficiency was 96.4%, and predictive value of a positive aspiration for a neoplasm was 98.3%. With fine-needle aspiration, surgical excision of salivary gland masses is often unnecessary. In patients with primary and metastatic neoplasms involving the salivary glands, fine-needle aspiration aids the surgeon in mapping the extent of the surgical procedure and in preoperatively preparing the patient. The procedure is cost-effective. H. TIDEMAN
Sind Stahlschrauben mit Titanplatten kombinierbar? Can steel screws be combined with titanium plates? R. W~chter, E Stol[ Dtsch Z Mund Kiefer GesichtsChir 1991: 15: 275-84.
Both V4A-steel and titanium have distinct advantages when considering osteosynthesis plates and screws. In particular, V2A and V4A steel are characterized by good mechanical qualities, removability and low costs, while ti-
tanium shows excellent biocompatibility, and resistance against corrosion and elasticity. A combination of these 2 materials could, theoretically, be of advantage for use in osteosynthesis. This should only be allowed if it does not have a detrimental effect on the materials' characteristics. To find if this was so, the authors performed unilateral osteotomies of the mandible in 24 sheep, comparing osteosynthesis by using A0 titanium plates fixed with steel screws. For comparison, titanium screws were used in the end of the plate during the same procedure. Tissue reaction was evaluated histologically 6, 12 and 24 weeks after the osteosynthesis, using DONATH'S & BREUNER'S (1982) sawing/grinding method. Nineteen of 24 specimens could be evaluated. Microscopic examination showed no signs of corrosion. Histologically, as well as in electronmicroscopy studies of the interface area between the plates and steel screws, minimal signs of corrosion were found after 12-24 weeks. N o signs of further changes in the cell metabolism could be demonstrated. The authors conclude that at least for temporary osteosynthesis, a combination of steel screws with titanium plates of the kind used can be allowed. Further studies, including Atom Absorption Spectroscopy methods, may be necessary to study minimal corrosion effects on the surrounding vital tissues. R. REICH
Vaskularisierte por~se Kunststoffe als Ger(istmaterial f~ir pr~iformierte freie Lappen, Vascularized porous plastic materials as a framework for free flaps H. W. H~rl, M. KI6ppel, E. Biemer Handchir Mikrochir Plast Chir 1991: 23: 32-8.
To further improve the effects of reconstructive surgery, a means to support
and shape a free microvascular anastomosed flap is necessary. For example, this could be of advantage in the reconstruction of large bony and soft tissue defects in the skull area and could lead to less morbidity at the donor site. It is known that this can be done by free bone and cartilage transplants. Alloplastic materials could also serve this purpose if accepted in the recipient bed. The authors performed an experimental study on 54 Wistar rats, Three porous synthetic materials and silicon rubber were implanted as framework into an area which later was taken as a free flap. The implant blocks were 2 x 3 x 8 mm in each case. Proplast II (polytetrafluorethylene-aluminiumoxide) was compared to Medpor (porous, high density polyethylene), Porecon (porous, high density polyethylene) and Silastic. In each case, a superficial circumflex ilium artery pedicled groin flap was developed and the alloplastic material was implanted. Eighteen animals in each group were followed for 2, 4 and 6 weeks. MacroscopicaUy, there was no evidence of inflammatory reaction. A microangiographic study showed the development of a capillary network in the 3 porous materials already 2 weeks postoperatively. Histologically, the implantation of porous materials did not lead to a fibrous connective tissue capsule, as was found in the Silastic cases. The ingrowth rate of soft tissue into the materials was highest in M e @ o r which represents 50% pore-volume, the pores measuring 50-700/xm in diameter. In Proplast II, the ingrowth process was slower; however, 6 weeks after implantation, all porous materials showed an ingrowth rate of 100%. Proplast II, which represents a 70-90% pore-volume rate, showed a more distinct foreign reaction compared to the other porous materials. The clinical relevance of these findings is still unclear but this study can be considered as a step towards the development of new tedhniques. R. R~rcH