Pelvic ring reconstruction with tibial allograft, screws and rods following enneking type I and IV resection of primary bone tumors*

Introduction: Surgery of primary malignant tumors involving the sacroiliac joint requires wide resection, which often interrupts the pelvic ring. Nowadays, restoration of the pelvic ring to provide stability and which technique is most fitting remain subject to debate. The aim of this study is to evaluate the results of pelvic reconstruction with pedicle screw instrumentation and tibial allograft following Enneking Type I-IV resections. Patients and methods: All patients who underwent reconstruction with tibial allograft, screws and rods after resection of areas I and IV for primary bone tumors between 2017 and 2022 were reviewed. Clinical and radiological characteristics, fusion rate and functional results were analyzed. The MSTS score and the TESS were used to evaluate functional results. Results: Seven patients were included in the study. Chondrosarcoma was the most common histology. Only four patients reported pain. No fractures were observed at tumor diagnosis. Computer-assisted navigation was used in six cases. Reconstruction was performed in four cases with a screw inserted in the homolateral L5 pedicle and in the ischium, in two cases with a screw in the homolateral L4 pedicle and another in the homolateral L5 pedicle, in the last case with two screws inserted in L4 and L5, one screw in the ischium and another one in the residual iliac wing. In this case a contralateral stabilization was also carried out. The spine screws and the iliac screws were connected with a rod. The mean follow-up for all 7 patients was 37 months. One patient (16.6%) died due to general complications not directly related to the surgery; while the others are alive and apparently free of disease. Complete fusion was obtained in four out of seven patients and the average time for fusion was 9 months. The average MSTS score and TESS were 58.7% and 57.8%, respectively. Discussion: The need for reconstruction is thoroughly debated in literature. The advantages of restoring posterior pelvis stability are the prevention of long-term pain associated with limb shortening and secondary scoliosis. Reestablishment of the pelvic ring can be achieved through synthetic, biologic or hybrid reconstructions. Conclusions: More studies that assess the surgical consequences at long-term follow-up and help clarify the indications for reconstruction and the specific technique are necessary to confirm our preliminary results.

Automated summary

This study evaluated the outcomes of pelvic reconstruction using pedicle screw instrumentation and tibial allograft after resection of primary malignant tumors involving the sacroiliac joint. The study found that complete fusion was achieved in 57.1% of the patients, with an average fusion time of 9 months. The functional results showed an average MSTS score of 58.7% and a TESS score of 57.8%. These preliminary results suggest that this technique has promising outcomes in initial reconstruction, but further research is needed to confirm the indications and long-term effects.