Periosteal Variety of Sacral Osteoid Osteoma Encroaching into the Spinal Canal – Treatment with a Tubular Retractor System: Case Report

Abstract

Background: Osteoid osteomas are benign primary bone tumors with a predilection for posterior elements of the spinal column. Complete surgical excision through a traditional open approach is the treatment of choice for patients not responding to non-steroidal anti-inflammatory medications and patients with contraindications for nidus ablation. The study aims to highlight an alternative minimally invasive technique for complete surgical excision of osteoid osteoma encroaching into the spinal canal. Methods: We report a case of 22 years-old obese male suffering from left S1 radiculopathy and night pain. Magnetic resonance imaging and computed tomography (CT)-scan of the lumbosacral region revealed a benign bony lesion of size 13 mm × 11 mm × 8 mm encroaching from S1 lamina into the spinal canal and compressing left S1 root. Peri-lesional bony sclerosis and soft tissue edema were absent. In view of obesity and a small size of the lesion, it was decided to remove the lesion with a tubular retractor system under general anesthesia. Complete resection of the lesion was carried out sparing the L5-S1 facet, with a minimally invasive approach. Results: Patient had complete symptomatic improvement after the surgery. Histopathology showed interconnected trabeculae of woven bone matrix rimmed by osteoclasts consistent with the diagnosis of osteoid osteoma. Post-operative CT scan showed that the nidus was removed completely and important structures such as facet, pedicle, and midline posterior ligament complex were preserved. The patient resumed his daily activities and remained symptoms-free at the end of 6 months of follow-up. Conclusion: Minimally invasive surgery using a tubular retractor system can be safe and effective alternative to traditional open surgery for excision of osteoid osteoma from the posterior elements. Faster recovery, minimal tissue damage, and early return to work are added advantages for an obese patient undergoing minimally invasive total surgical excision. Keywords: Benign bone tumors, Sacral spine, Osteoid osteoma, Periosteal osteoid osteoma, Minimally invasive spine surgery, Tubular retractor system