Biomedical engineering and basic research: historical perspectives.

The clinical potential of computer assisted surgery (CAS) has been more and more widely acknowledged since CAS systems have been introduced into the operating room (OR) theater. Especially the improvements in safety and accuracy are remarkable and strengthen the ties between surgeons and engineers. Tumor stereotaxis was introduced to neurological surgery in the early 1980s, and currently systems with and without robotic navigation are in use for specific medical indications. Recently, solutions for computer assisted orthopedic surgery were developed and applied to various anatomical regions. However, with the establishment of CAS in vivo, a new complex of problems, which was not present in the laboratory setup, was introduced: the man-machine interface. Currently, the complexity of available CAS systems requires the presence of at least one system engineer (often called the "operator") in the OR. As a consequence, there is no possibility for direct communication between the surgeon and the machine or software. Most of the program steps involved in CAS and choices to be made intraoperatively have to be transferred to the software by means of communication of the surgeon with the operator. Particularly, the establishment of a relation between the virtual object (i.e., a medical image) and the surgical object (i.e., the patient), often denoted as "matching" or "skeletal registration," requires intensive interaction of the surgeon with the computer. A literature survey revealed that no CAS system in clinical use exists without a system engineer or a comparable person, and our clinical experience indicated that the matching process is a weak point in most systems. Because it appears to be contradictory to cost-reduction efforts in health care to have a highly paid specialist in the OR, this research evaluates strategies to facilitate the man-machine interface with the final goal of establishing a direct control of the system by the surgeon or the medical personnel traditionally present at surgery. Options to be investigated include 1) a CAS control panel (virtual keyboard) as an integrated component of the existing navigation system and 2) introduction of a commercial voice-recognition system. The implementation of these strategies into the existing CAS setup at the Department of Orthopaedic Surgery at the Inselspital (University of Bern) and clinical experience gained are reported.

Biomedical Engineering↗

PubMed1997

The calcar femorale: a tale of historical neglect.

The term calcar femorale (originally referring to a bony spur projecting into the cancellous tissue of the base of the femoral neck) differs from most anatomical terms in that it has developed separate meanings in different areas of use. In particular, its present meaning for most orthopedic surgeons differs from its classical anatomical significance. This work shows that the classical, "textbook" anatomical interpretation-usually attributed to Merkel (1874, cited by Harty, 1957, J. Bone Joint Surg. [Am.] 39:625-630)-is not entirely correct, being based on an incomplete appreciation of the true nature of the three-dimensional structure of the upper end of the femur. Though Humphry (1858, A Treatise on the Human Skeleton, Cambridge, England: Macmillan) was aware of the importance of the third dimension, it was the largely neglected work of Dixon (1910, J. Anat. Physiol., 44:223-230), itself published to draw attention to the ideas of Krause (1909, in Bardeleben's Handbuch der Anatomie des Menschen, Jena: Gustav Fischer), which indicated the true nature of the calcar femorale and the limitations of Merkel's view. Dixon's work has been developed and consolidated by others such as Garden (1961, J. Bone Joint Surg. [Br.] 43:576-589), who was apparently unaware of Dixon, just as Dixon himself appears to have been unaware of the work of Bigelow (1875, published in Bigelow, 1900, The Mechanisms of Dislocations and Fracture of the Hip, Boston: Little, Brown), which pre-empted one of his major concepts. Even earlier work by Bigelow (1869, published in Bigelow; 1900, The Mechanisms of Dislocations and Fracture of the Hip, Boston: Little, Brown) appears to have pre-empted that of Merkel. The adoption of the three-dimensional, "Dixon concept" of the bony anatomy of the upper end of the femur leads to an entirely different set of structural engineering analogies from those two-dimensional ones which have become commonplace since the work of Ward (1838, cited by Garden, 1961, J. Bone Joint Surg. [Br.] 43:576-589) and Wolff (1870, cited by Keith, 1919, Menders of the Maimed, London: Frowde and Hodder & Stoughton).

Biomedical Engineering↗