Abstract
The technique of bone transport with a conventional Ilizarov external fixator is the current standard means of dealing with segmental bone defects not amenable to bone grafting. Problems with control of the distraction of regenerate bone frequently compromises treatment resulting in secondary deformity. Accurate docking of the defect bone ends is also complex to manage with the Ilizarov apparatus, corrections being possible in only one plane at a time (serial processing).
The Taylor Spatial external fixator (TSF), (Smith and Nephew, Memphis, Tennessee), is a modified Ilizarov fixator with six telescopic struts that are free to rotate at their connection points to the proximal and distal rings. This combination forms a Stewart Gough platform similar to that used in aircraft simulators. By adjusting only strut lengths, and applying Chasles theorem, one ring can be repositioned with respect to the other. Therefore with the aid of computer software, six axis deformities can be corrected simultaneously (parallel processing). We have used this device over the past 2 years in patients with segmental bone defects of the tibia in a stacked mode of application – a three ring construct with six struts between each pair of rings – to allow simultaneous accurately controlled distraction osteogenesis in one segment and independently controlled closure and compression at the docking site.
We present the results of 19 stacked Taylor Spatial frames in 19 patients treated with bone transport in the tibia. The diagnosis was bone resection for infected non union in fourteen, tumour resection in three and acute non infected bone loss secondary to trauma in two. The average age was 34.9 years, (range 10 to 69). Transport ranged from 4 to 12 cm. We used a distraction rate of 0.75mm/day and a comparable compression rate for closure of the defect. At the distraction site, angulation was controlled to within 1degree in any plane and translation to within 1mm in any direction, including length, allowing perfect alignment of the regenerate in all 19 cases. Regenerate quality was uniformly excellent. Superior control of the docking site compared with the Ilizarov fixator was consistently possible and the union rate was 100%. We observed no major complications of treatment. Minor complications included pin and wire infection and breakage all of which were treatable by simple measures with no long term sequelae.
In summary our experience with the stacked TSF for bone transport has shown it to be a highly reliable tool. We have achieved perfect control of regenerate bone in all axes and improved clinical outcomes for these complex problems.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
