A 62-year-old man affected by lymphoma with known skeletal metastases, was referred to our department with symptoms of refractory pain after non-operative therapy, which included chemotherapy, local radiotherapy, and opioid treatment. A month prior to the referral, the patient was admitted for a vertebroplasty for the T12, L1, L2 and L3 due to severe low back pain. The operation was significantly relieved from pain; however, the lower back pain progressively returned over the course of a month. Lumbosacral magnetic resonance imaging (MRI) and CT examinations (Fig. 1A, B) revealed an S1 mixed lesion. The patient had no weakness or neurosensory deficit.

After conferral with the orthopedic surgeon, discussion with the patient's family, and consent from the patient, percutaneous sacroplasty treatment was decided upon to restore sacrum stability and resolve the pain caused by the mixed lesion.

Prophylactic antibiotic therapy was performed by intravenous administration of 2 g of Cefuroxime Sodium (Livzon Medical Ltd, China), 30 minutes before commencing the procedure and was continued for 3 day after the procedure.

Before the procedure, a careful review of the radiology films and a measure of skin depth to the center of the lesion as well as the S1 marrow space from the dorsal to ventral cortex, were performed as specified by the trans-sacroiliac joint approach (Fig. 1C). The patient was placed in the prone position, comfortable and relaxed. Next, the lumbo-sacral region was prepped and draped to ensure sterility. The procedure was performed under local anesthesia. The sterile draped fluoroscope was positioned at the anteroposterior (AP) view. The lumbo-sacral junction was centered and the C-arm adjusted until the S1 foramen could be visualized. A small dermatotomy incision was made with a scalpel blade. Next, a 13-gauge bevel-edge needle (OptiMED Medizinische Instrumente GmbH, Germany) was introduced through the skin incision and subcutaneous tissue, to the periosteum of the bone, and then advanced to the center of the mixed lesion at the center of S1 transverse ilium, sacroiliac joint and sacrum (Fig. 1D, E) with the aid of a mallet. We adjusted the cephalopod and left-right angle according to the sagittal and axial films of CT and MRI until the needle attained the lesion under all fluoroscopy projections. After removal the inner needle, a commercial polymethyl methacrylate (PMMA) (Simplex P, Stryker Howmedica Osteonics, East Rutherford, NJ) was carefully injected carefully into the lesion under continuous fluoroscopic guidance in the lateral and AP projections (Fig. 1F, G) to ensure the adequate filling of the lesion and avoidance of PMMA leakage. A total of 6 ml of PMMA was injected. The post-procedural fluoroscopic findings showed optimal filling of the lesion with no evidence of PMMA extravasation.

The patient experienced significant pain relief the next day and was able to ambulate without assistance. The patient was discharged three days after the sacroplasty, following the completion of the prophylactic antibiotic therapy. Short-term (within 2 weeks) and middle-term (within 3 months) clinical follow-up were assessed by telephone. The physical examination elicited no pain upon palpation of the lumbosacral spine.

A 38-year-old woman was admitted to the hospital due to severe low back pain as a result of a sacral metastatic tumor associated with lung cancer (determined by a biopsy before the procedure). Both lumbo-sacral CT and MRI examinations showed an osteolytic change at the S1 level. The patient's image results revealed a destroyed cortex margin and was deemed not to be suitable for sacroplasty (Fig. 2A, B). However, the patient and her family strongly urged in favor of the operation, whatever the outcome. After obtaining informed consent, sacroplasty was performed under fluoroscopic guidance according to the technique described in Case 1. The procedure was well tolerated without significant complication except for the cement deposition in the needle track (Fig. 2C, D). Unfortunately, no CT images were available to display the distribution of PMMA to determine whether or not it leaked into neural foramina. However, the patient experienced considerable pain relief with no complaints of nerve root compression following the procedure. A 20 week post-operative follow-up over the telephone found that the patient experienced little pain and continued to walk independently.