Lumbosacral Fusion: The Mortised Transfacet Method by Use of the Vibrating Electric Saw for Circular Bone Blocks Earl D. McBride MD, Howard B. Shorbe MD CORR 1958;12:268-275

Field: Medicine (Health Sciences)

Reliably achieving spine fusion has been a problem since fusion was first described by Russell Hibbs of the New York Orthopaedic Hospital in 1911 [1]. Since that time, many dozens, if not hundreds of techniques have been proposed. PubMed lists over 1700 articles on the topic since 1935, many of which relate to techniques, and these 1700 articles undoubtedly reflect the tip of the iceberg. The reasons for performing a spine fusion have also varied and been greatly refined over the last century, and the success rates have varied depending, in addition to other factors, on both the reasons for the fusion and the technique. The article we highlight this month on lower lumbar spine fusion was published by Dr. Earl McBride and his colleague, Dr. Howard Shorbe, both of Oklahoma City [5]. Dr. McBride had been the founder and first President of the Association of Bone and Joint Surgeons (1947) [2, 3] which organized and has sponsored this journal since its inception in 1953. McBride and Shorbe noted, “a successful fusion depends on where and how the bone graft is implanted, not upon the amount of bone utilized” [5]. One of the more common reasons for surgery at the time was a ruptured disc, and they commented, “Removal of the offending disk protrusion alone is not likely to relieve the residual effects of progressive arthritic erosion and ligamentous weakness. How can such facts be ignored so completely?” [5] Their proposal was to fuse the facet joints, which often were arthritic in advance cases, using a dowel grafts cut by trephines on a vibrating saw and inserting those grafts into similar size cylindrical hole across the fact joints. They commented, “The nerve will not be damaged by the saw if it is directed properly and if correct depth adjustment has been made” [5]. Although mentioned in but a single sentence, this same point has been emphasized the past ten years or so with pedicle screws placed across the facet joints to achieve the same purpose: directing an implant in the proper direction requires great skill and knowledge. McBride and Shorbe [5] were not uniformly successful in achieving fusion: their rate of successful lumbar fusion was 91% at the L5-S1 level. When they operated on two levels, their rates of success were much lower: 65% at both levels. They noted, however, a successful fusion seen on a radiograph did not necessarily correlate with improvement of the patient: “…good and fair clinical healing was obtained in 97 percent of the total cases” [5]. They did not have the sophisticated instruments we do today in assessing success, and undoubtedly a contemporary assessment would lead to a lower clinical success rate. Nonetheless, their finding that successful bone fusion did not predict clinical outcome is consistent with a more recent report with the same finding in patients who had multiple back operations and other sorts of fusion [4]. Thus, their conclusion, “Satisfactory clinical results of facet graft fusions have always exceeded the number of cases showing solid bony union” [5] likely holds today.