Complications after Percutaneous Pedicle Screw Fixation for the Treatment of Unstable Spinal Metastases
Authors: Versteeg Anne , Verlaan Jorrit-Jan , de Baat Paul , Jiya Tim , Diekerhof Carel , van Solinge Guido , Oner F. C. 
Published: April 2016

Background Up to 70% of all cancer patients have bone metastases, with the spine being the most common location. Standard treatment of painful biomechanically unstable spinal metastases is surgical stabilization with or without cement augmentation. An extensive open surgical procedure may often not be warranted considering the palliative treatment intent. Minimally invasive surgical techniques such as percutaneous pedicle screw fixation have become available in the last decade and may be more suitable for these patients. Therefore, the aim of this study was to report the characteristics and complications after percutaneous pedicle screw fixation (PPSF) for the treatment of unstable spinal metastases. The secondary objective was to identify factors associated with the occurrence of complications and survival. Methods A national multicenter ambispective review of patients who underwent PPSF for the treatment of unstable spinal metastases was performed. Patients were excluded if they were diagnosed with a primary spinal tumor, an intradural spinal tumor, or if additional (minimal access) spine surgery was performed. Patient data pertaining demographics, diagnosis, treatment, neurological function, complications, and survival were collected. Results Between 2009 and 2014, 101 patients (56 female, mean age 60.3 ±11.2 years) underwent PPSF for the treatment of unstable spinal metastases. Median operating time was 122 minutes (range 57–325) with a median blood loss of 100ml ( N = 41, range 50–500); none of the patients required blood transfusion postoperatively. Median length of stay was 7 days with 78% of the patients ambulating within the first three days post-operative. The presence of complications ( p = 0.003) and need for re-operation ( p < 0.001) were associated with increased length of hospital stay. A total of 30 complications occurred in 18 patients. Operating time was the only factor associated with the presence of complications ( p = 0.041). Non-surgical adverse events (9%) were the most common complications followed by postoperative neurological deterioration (6%) and revision surgery (6%). Three out of six patients suffered neurological deterioration due to local tumor progression. The remaining three patients suffered surgical related neurological deterioration. Mean survival time was 11.0 months, with 78% of the patients being alive at three months post surgery. Univariate analysis demonstrated that a lower performance status ( p = 0.043), primary tumor type ( p < 0.001), the presence of node and/or visceral metastases ( p = 0.019) and no administration of postoperative chemotherapy ( p = 0.007) negatively influenced three months survival. Using multivariate analysis only no administration of postoperative chemotherapy ( p = 0.017, HR 5.8, 95%CI 1.79 – 18.77) demonstrated to be independently associated with impaired survival at three months. Conclusion Minimally invasive surgery for the treatment of spinal metastases demonstrates to be safe and has promising clinical outcomes in terms of minimal blood loss during surgery and high rates of early post-operative ambulation. In addition, no administration of postoperative chemotherapy was associated with impaired three months survival.