Preoperative Embolization of Metastatic Spinal Cord Compression with n-Butyl Cyanoacrylate: Safety and Effectiveness in Limiting Blood Loss.

PURPOSE: To evaluate the safety and effectiveness of preoperative embolization with n-butyl cyanoacrylate (nBCA) performed for metastatic spinal cord compression (MSCC) in limiting blood loss (BL). MATERIALS AND METHODS: In this institutional review board-approved retrospective study, clinical records from 2017 to 2022 were reviewed. Twenty consecutive patients (11 men and 9 women; mean age, 65.8 years ± 10.0; range, 45-82 years) underwent 21 preoperative spine tumor embolizations with nBCA. Angiograms were used to calculate the percentage reduction in tumor vascularity, and relevant clinical data (levels studied and embolized, fluoroscopy time [FT], reference dose [RD], and Kerma area product [KAP]) and operative data (BL and operative time [OT]) were analyzed. Adverse events and outcomes were recorded. RESULTS: A median of 2 levels were embolized per procedure (range, 1-5) but 4.9 were studied (range, 1-10). After embolization, tumor blush was reduced by a median of 87.3% (range, 50%-90%). The mean FT was 41 minutes ± 15.4 (range, 16-67 minutes), the mean RD was 1,977.1 mGy ± 1,794.3 (range, 450.2-6,319 mGy), and the mean KAP was 180.5 Gy·cm2 ± 166.2 (range, 30.4-504 Gy·cm2). The adverse event rate was 1 (4.7%) of the 21 embolizations because a weakness of lower extremities related to swelling was observed. Surgery was performed at a mean of 1.4 days ± 1 (range, 1-5 days) after embolization. The mean surgical estimated BL was 432.5 mL ± 328.5 (range, 25-1,100 mL), and the mean OT was 210.1 minutes ± 97.4 (range, 57-489 minutes). CONCLUSIONS: Preoperative embolization of tumors resected for MSCC with nBCA is a safe procedure allowing for performance of surgery with acceptable BL.

Short-segment cement-augmented fixation in open separation surgery of metastatic epidural spinal cord compression: initial experience.

OBJECTIVE: High-grade metastatic epidural spinal cord compression from radioresistant tumor histologies is often treated with separation surgery and adjuvant stereotactic body radiation therapy. Historically, long-segment fixation is performed during separation surgery with posterior transpedicular fixation of a minimum of 2 spinal levels superior and inferior to the decompression. Previous experience with minimal access surgery techniques and percutaneous stabilization have highlighted reduced morbidity as an advantage to the use of shorter fixation constructs. Cement augmentation of pedicle screws is an attractive option for enhanced stabilization while performing shorter fixation. Herein, the authors describe their initial experience of open separation surgery using short-segment cement-augmented pedicle screw fixation for spinal reconstruction. METHODS: The authors performed a retrospective chart review of patients undergoing open (i.e., nonpercutaneous, minimal access surgery) separation surgery for high-grade epidural spinal cord compression using cement-augmented pedicle screws at single levels adjacent to the decompression level(s). Patient demographics, treatment data, operative complications, and short-term radiographic outcomes were evaluated. RESULTS: Overall, 44 patients met inclusion criteria with radiographic follow-up at a mean of 8.5 months. Involved levels included 19 thoracic, 5 thoracolumbar, and 20 lumbar. Cement augmentation through fenestrated pedicle screws was performed in 30 patients, and a vertebroplasty-type approach was used in the remaining 14 patients to augment screw purchase. One (2%) patient required an operative revision for a hardware complication. Three (7%) nonoperative radiographic hardware complications occurred, including 1 pathologic fracture at the index level causing progressive kyphosis and 2 incidences of haloing around a single screw. There were 2 wound complications that were managed conservatively without operative intervention. No cement-related complications occurred. CONCLUSIONS: Open posterolateral decompression utilizing short-segment cement-augmented pedicle screws is a viable alternative to long-segment instrumentation for reconstruction following separation surgery for metastatic spine tumors. Studies with longer follow-up are needed to determine the rates of delayed complications and the durability of these outcomes.

Utility of Cement Augmentation via Percutaneous Fenestrated Pedicle Screws for Stabilization of Cancer-Related Spinal Instability.

BACKGROUND: Cancer patients experience pathological fractures and the typical poor bone quality frequently complicates stabilization. Methods for overcoming screw failure include utilization of fenestrated screws that permit the injection of bone cement into the vertebral body to augment fixation. OBJECTIVE: To evaluate the safety and efficacy of cement augmentation via fenestrated screws. METHODS: A retrospective chart review of patients with neoplastic spinal instability who underwent percutaneous instrumented stabilization with cement augmentation using fenestrated pedicle screws. Patient demographic and treatment data and intraoperative and postoperative complications were evaluated by chart review and radiographic evaluation. Prospectively collected patient reported outcomes (PRO) were evaluated at short (2- <6 mo) and long term (6-12 mo). RESULTS: Cement augmentation was performed in 216 fenestrated pedicle screws in 53 patients. Three patients required reoperation. One patient had an asymptomatic screw fracture at 6 mo postoperatively that did not require intervention. No cases of lucency around the pedicle screws, rod fractures, or cement extravasation into the spinal canal were observed. Eight cases of asymptomatic, radiographically-detected venous extravasation were found. Systemic complications included a pulmonary cement embolism, a lower extremity deep vein thrombosis, and a postoperative mortality secondary to pulmonary failure from widespread metastatic pulmonary infiltration. Significant improvement in PRO measures was found in short- and long-term analysis. CONCLUSION: Cement augmentation of pedicle screws is an effective method to enhance the durability of spinal constructs in the cancer population. Risks include cement extravasation into draining blood vessels, but risk of clinically significant extravasation appears to be exceedingly low.

Safety and utility of kyphoplasty prior to spine stereotactic radiosurgery for metastatic tumors: a clinical and dosimetric analysis.

OBJECTIVE The aim of this study was to evaluate the safety and efficacy of kyphoplasty treatment prior to spine stereotactic radiosurgery (SRS) in patients with spine metastases. METHODS A retrospective review of charts, radiology reports, and images was performed for all patients who received SRS (single fraction; either standalone or post-kyphoplasty) at a large tertiary cancer center between January 2012 and July 2015. Patient and tumor variables were documented, as well as treatment planning data and dosimetry. To measure the photon scatter due to polymethyl methacrylate, megavolt photon beam attenuation was determined experimentally as it passed through a kyphoplasty cement phantom. Corrected electron density values were recalculated and compared with uncorrected values. RESULTS Of 192 treatment levels in 164 unique patients who underwent single-fraction SRS, 17 (8.8%) were treated with kyphoplasty prior to radiation delivery to the index level. The median time from kyphoplasty to SRS was 22 days. Four of 192 treatments (2%) demonstrated local tumor recurrence or progression at the time of analysis. Of the 4 local failures, 1 patient had kyphoplasty prior to SRS. This recurrence occurred 18 months after SRS in the setting of widespread systemic disease and spinal tumor progression. Dosimetric review demonstrated a lower than average treatment dose for this case compared with the rest of the cohort. There were no significant differences in dosimetry analysis between the group of patients who underwent kyphoplasty prior to SRS and the remaining patients in the cohort. A preliminary analysis of polymethyl methacrylate showed that dosimetric errors due to uncorrected electron density values were insignificant. CONCLUSIONS In cases without epidural spinal cord compression, stabilization with cement augmentation prior to SRS is safe and does not alter the efficacy of the radiation or preclude physicians from adhering to SRS planning and contouring guidelines.