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The ‘relay’ graft
71
Abstracts patient as soon as possible-what degree of recovery can be expected. Severe injuries with little or no prospect of useful recovery are accompanied by paralysis of the thoracoscapular and the posterior muscles, by persistence of the axon reflex and by myelographic evidence of meningeal pouches or of obliteration of the roots’ pouches. These are the signs of intradural rupture; severe pain and Horner’s syndrome often occur but do not necessarily augur ill. When the clinical evidence points to an extradural injury, exploration and electrical testing should be carried out within 48 hours if there is to be any chance of repairing ruptured roots. This may be of some benefit with small lesions. The following plans of action are offered. If there is paralysis of the thoracoscapular muscles, amputate if the patient wishes to be rid of the limb. Otherwise no treatment is of any value. If there is active control of the scapula with an extensive and irrecoverable lesion, amputate the arm and secure bony ankylosis of the shoulder within a few weeks. If there is poor control of the shoulder but useful function in the hand, use pectoralis major to bend the elbow, and stabilize the shoulder by arthrodesis or tenodesis. Good flexor muscles in the forearm can be shifted upwards to act as flexors for the elbow. If there is partial recovery of the hand and wrist, arthrodesis and re-implantation of tendons are worth while. For severe pain, drugs and sympathectomy are of little use and cordotomy is potentially dangerous. BONNEYG. (1974) Injuries of the brachial plexus. Br. J. Hosp. Med. 11, 567. A possible
new alloy for implants
An alloy of cobalt, nickel, chromium and molybdenum named MP35N and developed for its strength and corrosion-resistance in industry is suggested as a possible implant. Tensile strength, yield strength and elastic modules are better than in metals used at present. In vitro corrosion testing seems satisfactory but in vivo testing has not yet been very extensive. YONKIN C. N. (1974) Multiphase MP35N alloy for medical implants. J. Biomed. Mater. Res. Symposium 5 (Part i), 219. A corrosion-resistant
The ’ relay ’ graft This paper describes an ingenious use of the mesh skin graft to allow even greater epithelial cover of very large skin defects. A fully-expanded mesh graft is allowed to remain on a raw surface for 5-7 days during which time epithelium will grow into the ‘ window-spaces ’ left between the lattice work of the mesh. The mesh graft is then lifted off the wound and relaid to cover another part of the raw surface. This ‘ relaid graft ’ behaves like any normal mesh graft and will take perfectly well. In the meantime the ‘-islands ’ of e&helium left at the site of the first imulant will have spread to give complete epithelial cover at that site. The indications for using this technique will not often occur, but its possible value is obvious. SMAHELJ. (1972) Br. J. Plast. Surg. 25, 432. Fatigue
in silastic
finger
joints
These prostheses cyclically stressed in serum will withstand 10 million cycles, but in practice they have been known to break after as little as 14 months. Chemical inertness of the material is far from perfect in the body and surface degeneration may be the starting point of fatigue failure. One detail of insertion technique is criticized. WEIGHTMANB., SIMON S., ROSE R., PAUL I. and RADIN E. (1972) Environmental fatigue testing of silastic finger ioint prostheses. J. Biomed. Mater. Res.
-
6,15.
-
Oxygen
poisoning
alloy
One of the newer alloys (Ti-6AL-4V) was tested in vitro for corrosion. It was found to corrode nearly 200 times slower than type 316L stainless steel, at present considered acceptable in clinical practice. The question of toxicity of the corrosion products was outside the terms of reference of this work. ARAGONP. J. and HULBER~S. F. (1972) Corrosion of Ti-6Al-4V in simulated body fluids and bovine plasma. J. Biomed. Mater. Res. 6, 155. Failure
another made of stainless steel had bent, and a fourth of the same metal had corroded to the extent of causing pain and requiring removal. This metallurgical report contains the following points. Corrosion, fretting corrosion, crevice corrosion and corrosion-fatigue cracking all occur with EnSSJ. Imperfect heat treatment in manufacture caused one failure; elementary design precautions had been ignored in one very popular implant; ‘ incredible ’ errors in marking another had been made. The surgeon does not escape responsibility; it seems that he may be guilty of abusing implants so that they are subjected to stresses far higher than were ever intended. HUGHESA. N. andJoRDANB. A. (1972) Metallurgical observations on some surgical implants which have failed in vivo. J. Biomed. Mater. Rex 6, 33.
in implants
Of 5 implants that had given trouble in service, 2 made of stainless steel and 1 made of titanium had broken,
of the lungs
Dogs breathing 95 per cent oxygen were found to develop pulmonary insufficiency. Over a 72-hour experiment the arterial PO, decreased from about 500 mm to 1OOmm. Biopsy revealed lung oedema. The effects were more marked in animals breathing spontaneously than in those being mechanically ventilated. It took up to 10 days for the lungs to return to normal when the animals were returned to breathing air. WOLFEW. G. and SABISTON D. C. iun. (1973) Luna function in spontaneously breathing and mechanical& ventilated dogs exposed to ninety-five per cent oxygen. Surg. Gynecol.
Obstet.
137, 763.
Abstracts patient as soon as possible-what degree of recovery can be expected. Severe injuries with little or no prospect of useful recovery are accompanied by paralysis of the thoracoscapular and the posterior muscles, by persistence of the axon reflex and by myelographic evidence of meningeal pouches or of obliteration of the roots’ pouches. These are the signs of intradural rupture; severe pain and Horner’s syndrome often occur but do not necessarily augur ill. When the clinical evidence points to an extradural injury, exploration and electrical testing should be carried out within 48 hours if there is to be any chance of repairing ruptured roots. This may be of some benefit with small lesions. The following plans of action are offered. If there is paralysis of the thoracoscapular muscles, amputate if the patient wishes to be rid of the limb. Otherwise no treatment is of any value. If there is active control of the scapula with an extensive and irrecoverable lesion, amputate the arm and secure bony ankylosis of the shoulder within a few weeks. If there is poor control of the shoulder but useful function in the hand, use pectoralis major to bend the elbow, and stabilize the shoulder by arthrodesis or tenodesis. Good flexor muscles in the forearm can be shifted upwards to act as flexors for the elbow. If there is partial recovery of the hand and wrist, arthrodesis and re-implantation of tendons are worth while. For severe pain, drugs and sympathectomy are of little use and cordotomy is potentially dangerous. BONNEYG. (1974) Injuries of the brachial plexus. Br. J. Hosp. Med. 11, 567. A possible
new alloy for implants
An alloy of cobalt, nickel, chromium and molybdenum named MP35N and developed for its strength and corrosion-resistance in industry is suggested as a possible implant. Tensile strength, yield strength and elastic modules are better than in metals used at present. In vitro corrosion testing seems satisfactory but in vivo testing has not yet been very extensive. YONKIN C. N. (1974) Multiphase MP35N alloy for medical implants. J. Biomed. Mater. Res. Symposium 5 (Part i), 219. A corrosion-resistant
The ’ relay ’ graft This paper describes an ingenious use of the mesh skin graft to allow even greater epithelial cover of very large skin defects. A fully-expanded mesh graft is allowed to remain on a raw surface for 5-7 days during which time epithelium will grow into the ‘ window-spaces ’ left between the lattice work of the mesh. The mesh graft is then lifted off the wound and relaid to cover another part of the raw surface. This ‘ relaid graft ’ behaves like any normal mesh graft and will take perfectly well. In the meantime the ‘-islands ’ of e&helium left at the site of the first imulant will have spread to give complete epithelial cover at that site. The indications for using this technique will not often occur, but its possible value is obvious. SMAHELJ. (1972) Br. J. Plast. Surg. 25, 432. Fatigue
in silastic
finger
joints
These prostheses cyclically stressed in serum will withstand 10 million cycles, but in practice they have been known to break after as little as 14 months. Chemical inertness of the material is far from perfect in the body and surface degeneration may be the starting point of fatigue failure. One detail of insertion technique is criticized. WEIGHTMANB., SIMON S., ROSE R., PAUL I. and RADIN E. (1972) Environmental fatigue testing of silastic finger ioint prostheses. J. Biomed. Mater. Res.
-
6,15.
-
Oxygen
poisoning
alloy
One of the newer alloys (Ti-6AL-4V) was tested in vitro for corrosion. It was found to corrode nearly 200 times slower than type 316L stainless steel, at present considered acceptable in clinical practice. The question of toxicity of the corrosion products was outside the terms of reference of this work. ARAGONP. J. and HULBER~S. F. (1972) Corrosion of Ti-6Al-4V in simulated body fluids and bovine plasma. J. Biomed. Mater. Res. 6, 155. Failure
another made of stainless steel had bent, and a fourth of the same metal had corroded to the extent of causing pain and requiring removal. This metallurgical report contains the following points. Corrosion, fretting corrosion, crevice corrosion and corrosion-fatigue cracking all occur with EnSSJ. Imperfect heat treatment in manufacture caused one failure; elementary design precautions had been ignored in one very popular implant; ‘ incredible ’ errors in marking another had been made. The surgeon does not escape responsibility; it seems that he may be guilty of abusing implants so that they are subjected to stresses far higher than were ever intended. HUGHESA. N. andJoRDANB. A. (1972) Metallurgical observations on some surgical implants which have failed in vivo. J. Biomed. Mater. Rex 6, 33.
in implants
Of 5 implants that had given trouble in service, 2 made of stainless steel and 1 made of titanium had broken,
of the lungs
Dogs breathing 95 per cent oxygen were found to develop pulmonary insufficiency. Over a 72-hour experiment the arterial PO, decreased from about 500 mm to 1OOmm. Biopsy revealed lung oedema. The effects were more marked in animals breathing spontaneously than in those being mechanically ventilated. It took up to 10 days for the lungs to return to normal when the animals were returned to breathing air. WOLFEW. G. and SABISTON D. C. iun. (1973) Luna function in spontaneously breathing and mechanical& ventilated dogs exposed to ninety-five per cent oxygen. Surg. Gynecol.
Obstet.
137, 763.