[Transpedicular implantation of screws in the thoracolumbar spine. Results of a survey of methods, frequency and complications]

Abstract

Pedicular fixation has found great acceptance as a modality for spinal fusions. Being a "blind technique" it is associated with a potential high risk of neural and vascular morbidity. In an attempt to evaluate and/or establish a uniformly accepted concept of surgical management we designed a questionnaire composed of seventeen questions dealing with different pre-, intra- and postoperative procedures in transpedicular fixation. This was sent to 31 experienced surgeons organized in the working group "spine" of the german trauma association. Half of the answers to each question were similar. The other half however, showed a wide variation of thought. It is thus deduced that although some concepts are frequently applied there is no general agreement to an optimal method of surgical handling. Most surgeons use conventional operative cushions for positioning the patients (22/31). Access is usually proceeded by sharp dissection of the lumbodorsal fascia using a scalpel instead of catheterization (21/31), consciously avoiding traumatisation of paravertebral muscle insertion to the transverse processes (22/31), as well as sparing the dorsal branch of segmental arteries (25/31). Intraoperative orientation is attained by inspection coronary and fluoroscopy sagittal (15/31). Most surgeons remove cortical bone using a Rongeur (22/31), transpedicular drill hole is prepared by means of a k-wire (11/31), for orientation again the fluoroscope is made use of (15/31). On perforating the medial boundary of the pedicle thirteen operators correct the direction on drilling, on perforating the lateral boundary twelve medialise the screws on fixation, and eleven surgeons would leave the screws in place if firm holding is warranted. Half of the questioned surgeons simply lateralise the screws if cerebrospinal fluid leaked from the drill holes. If a malposition of the pedicle screws is not suspected no control computer tomography is performed (21/31). Regarding these facts a comparative evaluation of the different techniques used in transpedicular fixation is lacking. In our opinion further multicenter evaluation is necessary to establish a unified method and thus optimize postoperative results.