Creation of false pedicles and a neo-pelvis for lumbopelvic reconstruction following en bloc resection of an iliosacral chondrosarcoma with lumbar spine extension

Abstract

En bloc resection with negative tumor margins remains the principal treatment option for control or cure of primary pelvic chondrosarcomas, as current adjuvant therapies remain ineffective. Iliosacral chondrosarcomas with involvement of the sciatic notch are sufficiently challenging tumors. However, when there is concomitant lumbar extension requiring resection of the pedicles to maintain negative surgical margins, transpedicular screw fixation is not possible, making reconstruction of the lumbopelvic junction extremely challenging. A patient with an iliosacral chondrosarcoma with lumbar spine extension is presented in this report to illustrate a novel lumbopelvic spinal construct. Following combined external pelvectomy and hemisacrectomy with contralateral L3–5 hemilaminectomy and ipsilateral pediculotomy, bicortical transvertebral body screws were substituted for the missing pedicles, resulting in the creation of “false pedicles,” which were further supplemented with an autologous vascularized fibular strut graft from the amputated lower limb and applied to the lateral aspect of the vertebral bodies. The creation of false pedicles allowed for a robust reconstruction of the lumbopelvic junction, including maintaining pelvic ring integrity with a “neo-pelvis”, creating a functional load-bearing construct adequate for early mobilization and ambulation. The biomechanical dynamics of this unique construct are also discussed.

Patient-Specific Three-Dimensional Model for a Safe Surgical Pathway in Sacral Chondrosarcoma

“…Sacral resection is a procedure with the potential to influence quality of life drastically [1,3,6,11,16,19]. In sarcoma surgery, removal of tumor mass without extensive excision is essential.…”

“…Due to the complex anatomy, the presence of proximal neurovascular bundles, and high risk of infection, it is only performed in selected cases where sacrectomy can influence patients' prognosis [13,14]. Removing more than 50% of the S1-2 vertebra/sacral ala can result in lumbopelvic instability [15,16]. Reconstruction of the spine-pelvic connection and spinopelvic fixation are needed [17].…”