Percutaneous pedicle screw placement
Percutaneous biopsy of pathology in the pedicle and/or vertebral body
1.- Requires AP and lateral fluoroscopy, or O Arm imaging.
Acquiring two simultaneous images from two orthogonal planes has been reported to be more efficient than single-plane imaging.
2.- Can be employed from T1 through S1 as long as adequate AP & lateral imaging of the involved level is possible.
Upper thoracic placement (above T5) is challenging shoulder interference small pedicles.
3.- The skin entry site is lateral to the lateral edge of the pedicle. This permits the needle to pass through the pedicle off the midline for the entry site depending on the vertebral level being accessed (thoracic pedicles are oriented in a more AP direction, lumbar pedicles angulate medially inward) as well as the amount of overlying muscle/fat.
Forty patients with thoracic and lumbar metastatic tumors were treated with PPSF combined with PVP and followed up for 6-33 months. The visual analog scale (VAS) and the Barthel Index of activities of daily living (BIADL) were used to evaluate the pain intensity and quality of life before surgery and at 7 days, 3 months, and 6 months after the treatment.
Results: In this study, a total of 40 patients were followed up for 6-33 months (the meantime was 14.87 months). The VAS scores of all patients were significantly decreased, while the BIADL scores were significantly increased. No patients suffered from complications such as infection, pedicle screw loosening, or polymethylmethacrylate leakage. Spine stability was observed in all surviving patients during the follow-up.
Conclusions: PPSF combined with PVP is a new and viable treatment for thoracolumbar metastases in patients with a poor systemic condition, patients who refuse to undergo a conventional open procedure such as en bloc corpectomy, and in patients with vertebral instability or pathological fracture without significant spinal compression.
Relevance for patients: Patients with spinal metastases have a great risk of spinal instability and even spinal cord compression while enduring pain. Therefore, timely and appropriate surgical treatment is an effective means to stabilize the spine and avoid spinal cord compression. PPSF combined with percutaneous vertebroplasty is an effective new surgical method for the treatment of multilevel spinal metastases 1).
Survival of cancer patients continues to improve with systemic treatment advancements, leading to an increase in cancer-related complications such as pathological spinal fractures. In a study, Meleis et al. aimed to evaluate the outcome of percutaneous stabilization with cement augmentation of the pedicle screws in the management of patients with metastatic cancer to the spine.
They reviewed a retrospective case series of 74 patients with symptomatic pathological spine fractures treated with cement-augmented pedicle screws implanted with a percutaneous technique. The mean imaging follow-up was 11.3 months. Data on demographics, clinical outcomes, and complications were collected. Cement extravasation, spinal hardware integrity, and fusion rates were assessed on CT scans.
Among 50 patients with follow-up imaging, 23 patients (46%) showed facet joint fusion. The length of segmental stabilization was not a significant predictor of the occurrence of fusion. Pre- or postoperative radiation therapy, postoperative chemotherapy, and the location of spinal lesions did not have a statistically significant effect on the occurrence of fusion. Patients older than 60 years of age were more likely to have fusion across facet joints compared with younger patients. There was a significant difference in the mean visual analog scale pain score, with 6.28 preoperatively and 3.41 postoperatively, regardless of fusion status (p < 0.001). Cement extravasation was seen in 51% of the cohort, but in all instances, patients remained asymptomatic. Most importantly, the incidence of hardware failure was low (4%).
Percutaneous fixation with cement-augmented pedicle screws in patients with pathological spine fractures provides an improvement in mechanical back pain, with a low incidence of failure, and in some patients, spontaneous facet fusion was observed. Further research is necessary with regard to both short-term benefits and long-term outcomes 2).