Transpedicular lumbosacral fixation for non-traumatic disorders.

Correspondence We welcome letters to the Editor concerning articles which have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply. Letters should normally be under 300 words in length, double-spaced throughout, signed by all authors and fully referenced. The edited version will be returned for approval before publication. Sir, The recent paper in the March 1997 issue by Pihlajamäki, Mylly-nen and Böstman 1 on the complications of transpedicular lumbo-sacral internal fixation has, like many others, not discussed two variables which have an important bearing on the outcome of spinal fusion. 1) There is clearly an optimal degree of lordosis when standing , although this varies considerably from person to person (Constant, unpublished data). Failure to recognise and incorporate a lordosis appropriate to an individual's balanced posture may be a cause of persisting back pain, perhaps due to an overcompensa-tion at adjacent segments for an inappropriate position of fusion. In Figure 6, judging by the alignment of the broken screws, it seems that the posture of choice, regained after the screws had broken, is more lordosed than that originally produced by the surgery. 2) The integrity of the suprainterspinous ligament complex and its reattachment to spinous processes are important for controlling the vertebrae. This ligament is often no more than a 0.5 mm wide on each side and is often destroyed during spinal surgery. It is not unusual to see it become 'bow strung' dorsal to the spinous processes, with a curious 'valley between two ridges' visible under the incision scar. This loss of control on each segment may add to the complications and morbidity after operation. Displacement of the dorsal vertebral muscles from their natural gutter by the pedicular screw apparatus should also be considered as a serious disadvantage of the system. Complications of trans-pedicular lumbosacral fixation for non-traumatic disorders. Sir, We thank Dr J. P. Driver-Jowitt for his interest in our paper. We are aware of the potential importance of restoring natural lordosis at the level of fusion. Preoperative extension-flexion radiographs were used to give the surgeon an idea of the required lordosis in each case. During operation, the degree of lordosis was assessed and adjusted according to the information obtained using the C-arm of the image intensifier in a horizontal position to give a lateral view …