Professor of Orthopaedic Surgery; Harvard Medical; School Orthopaedic Surgeon-in-Chief, Emeritus Specialist, Spine Surgery; Beth Israel Deaconess Medical Center; Boston, Massachusetts
Four cases are presented of patients seen in a leper colony in South Vietnam. The patients presented with evidence of osteolysis, arthropathies and severe scarrings of the skin. They were without pain and in generally good health. There were no neurologic or vascular deficit. They had positive serological tests for syphilis. Other known types of osteolysis are discussed including leprosy and the treponemal diseases, and the cases are presented as a previously undescribed entity.
Based on a review of previous studies and our opinion, biomechanical considerations suggest the following guidelines for the surgical management of CSM. It is not recommended that the dura mater, the pia mater, and the dentate ligaments be transected in the surgical treatment of CSM. Anterior decompression and fusion, preferably with the Smith-Robinson technique, is recommended for patients with anterior impingement of the spinal cord at one or two levels in the absence of a narrow spinal canal. This procedure is also advantageous when there is significant radiculopathy associated with the level(s) of pathology. Posterior decompression is recommended when there are three or more levels involved, and particularly when there is developmental stenosis of the canal, ie, a DAD below 13 mm and a SAD below 11 mm. Laminectomy and laminoplasty for CSM may not be any different as regards surgical outcome. One well-controlled study showed only one difference, a decrease in the ability of the laminoplasty patients to extend the neck. If there is evidence of instability or a potential for it, posterior decompression procedures should be accompanied by a facet fusion, or in the case of laminoplasty, some fusion modification such as that described by Itoh and Tsuji. There may also be circumstances in which significant multilevel anterior spur formation and compression in association with a stenotic canal should be treated with anterior and posterior surgery with appropriate attention to maintaining adequate stability. The advantages and disadvantages of these various surgical procedures and their relative appropriateness in various clinical situations will be gradually clarified through well-designed and executed laboratory and clinical investigations.
Rabbit femora and ulnae were tested to fracture in a torsion loading experiment. Various mechanical parameters were determined under five loading rates ranging from 0.003 to 13.2 radians per second. The maximum torque, maximum torsional deformation, energy absorbed to fracture, and torsional stiffness all increased with the rate of deformation, reached a maximum, and then declined. The bones absorbed 67 per cent more energy, had 33 per cent more torque and torsional deformation, and 5 per cent more stiffness at the highest rate of deformation as compared with the lowest.
Abstract An epidemiologic case‐control study undertaken in Connecticut during 1979–1981 indicated that persons with jobs requiring lifting objects of more than 11.3 kg (25 lb) an average of more than 25 times per day had over three times the risk for acute prolapsed lumbar intervertebral disc as people whose jobs did not involve lifting objects of this weight. If the body was usually twisted while the lifting was done, this elevation in risk was apparent with less frequent lifting. An especially high risk for prolapsed lumbar disc was associated with jobs involving lifting objects of more than 11.3 kg with the body usually twisted and the knees not bent while the lifting was done. Neither lifting objects of less than 11.3 kg nor twisting without lifting was associated with an increase in risk.
