Pelvic Girdle Reconstruction Based on Spinal Fusion and IschialScrew Fixation in a Case of Aneurysmal Bone Cyst

Abstract

A case of lytic lesion of the pelvis in a 23-year-old woman is presented. A biopsy led to the diagnosis aneurysmal bone cyst (ABC). Due to the histologically very aggressive growth of the tumor, a low malignant osteosarcoma could not be excluded. In an initial operation the tumour, affecting the sacrum, the iliac crest and the lower lumbar spine was resected. Temporary restabilisation of the pelvic ring was achieved by a titanium plate. The histological examination of the entire tumour confirmed the diagnosis ABC. After 6 months, the MRI showed no recurrence. The observed tilt of the spine to the operated side on the sacral base prompted a second surgical procedure: a transpedicular fixation of L5 and L4 was connected via bent titanium stems to the ischium, where the fixation was achieved by two screws. This construction allowed the correction of the base angle and yielded a stable closure of the pelvic ring. The patient has now been followed for 6 years: the bone grafts have been incorporated and, in spite of radiological signs of screw loosening in the ischium, the patient is fully rehabilitated and free of symptoms. Pedicle screws in the lower spine can be recommended for fixation of a pelvic ring discontinuity.Key Words: aneurysmal bone cyst, pelvic reconstruction, spino ischial spondylodesils, pelvic tumor A 23-year-old woman presented with a low back pain (LBP) history of 2 years. Plain film radiographs and an MRI of the lumbar spine had not shown any pathologies. The patient had been treated with drugs and physical therapy. The patient was referred to our hospital since the pain increased, especially during the night with referral to the legs. A new X-ray examination of the spine showed a cystic structure in the sacral bone. Immediately following this discovery, images of the whole pelvis were taken, revealing a lytic lesion of the left pelvis involving the ilium near the acetabular roof, the sacrum near the spinal canal, and also the left L5-lamina (Fig. 1). An open biopsy was performed. The histological examination revealed multiple communicating vascular spaces separated by fibrous septa. Some areas showed suspicious bone lesions. The histological diagnosis was aneurysmal bone cyst (ABC) but, due to the very aggressive growth of the tumour, a low malignant osteosarcoma could not be excluded.Therefore the strategy of operative treatment was an initial wide tumour resection and temporary stabilisation of the pelvic ring. After histological examination of the entire lesion, a subsequent operation was planned to reconstruct the pelvic ring with custom-made implants and graft material.A combined anterior and posterior approach in a lateral decubitus position was used to carry out the wide tumour resection. The tumour had spread into the L5-lamina, the left part of the sacrum, the iliac crest, and the ileum down to the level of the back side of the articular cartilage of the acetabulum. Primary stabilisation of the pelvic ring was achieved by mounting a 12-hole titanium osteosynthetic plate between t...

Aneurysmal bone cyst of the pelvis: systematic literature review

“…but according to the reports, the key to overcome these issues is to get a near anatomic reconstruction of the pelvic defects. Currently triradiate iliac crest grafts, vascularized or non-vascularized bular grafts, allografts, custom-made mega prosthesis, extracorporeal irradiated pelvic bone and re-implantation have all been described [20,18,[36][37][38]. Zidzislaw et al predicts that the future for pelvic defects is statistical shape model (SSM) reconstruction method using mirroring approach.…”

"Aneurysmal Bone Cyst of the Pelvis: A Systematic Literature Review"

“…but according to the reports, the key to overcome these issues is to get a near anatomic reconstruction of the pelvic defects. Currently triradiate iliac crest grafts, vascularized or non-vascularized bular grafts, allografts, custom-made mega prosthesis, extracorporeal irradiated pelvic bone and re-implantation have all been described [20,18,[36][37][38]. Zidzislaw et al predicts that the future for pelvic defects is statistical shape model (SSM) reconstruction method using mirroring approach.…”