Versatility of Percutaneous Pedicular Screw Fixation in Metastatic Spine Tumor Surgery
Authors: Kumar Naresh , Zaw Aye Sandar 
Published: May 2015

Background Minimally invasive surgery has been evolved to address the problems associated with metastatic spine diseases (MSD). Posterior percutaneous spinal fixation (PPSF) is one of the main modalities of minimally invasive surgery. There have been several studies which evaluated the outcomes PPSF, but none of them assessed in detail regarding the versatility of PPSF in MSD. This study was designed to evaluate feasibility and spectrum of application of PPSF in management of MSD, highlighting its clinical advantages. Methods A total of 27 consecutive patients with MSD treated with PPSF in our institution from January 2011 to June 2014 were studied. All the patients, after a multidisciplinary assessment, were considered for surgical intervention because of clinical presentation of either neural deficit, skeletal instability, or both. Some of these patients belonged to poor-prognostic category based on survival prognostic scoring systems. The patients were categorized into seven groups depending on the modality of PPSF used. The categories are as follows (1) Pure skeletal stabilization, (2) Posterior stabilization with decompression, (3) Posterior stabilization with decompression and partial corpectomy, (4) Posterior stabilization with decompression plus kypho/vertebrolplasty, (5) Long construct with 2 to 3 level skip decompression, (6) Short/long construct with iliac stabilization, (7) Short/long construct pus anterior corpectomy. PPSF groups 2, 3, and 4 were collapsed into one group and groups 5 and 6 into the other group because of the similarity of these procedures barring some minor differences in complexity between the groups. The analysis was then stratified by the four groups of PPSF modalities and therefore the different variables in each group could be explored and compared. Demographic data, operative details, and clinical outcomes were investigated for each category and compared preoperatively and postoperatively. Results The median age was 60 years (range, 49–78 years). t test revealed significant difference between preoperative and postoperative mean VAS score in all groups except group 4. Significant difference between pre- and postoperative ECOG scores were seen in group 2. None of the patients in any group showed any worsening in neurological status in postoperative period. Some patients in group 2 and 3 showed improvement in neurological status. Full normal function (Frankel score E) was achieved postoperation in 88% of patients in PPSF group 1, 89% in group 2, 71% in group 3, and 50% in group 4. The differences in these scores between pre- and postoperation, however, did not reach statistically significant level. Independent ambulation was observed within 3 months of surgery in 100% in PPSF group 1, 80% in group 2, 84% in group 3, and 50% in group 4. Pure stabilization group had the lowest amount of mean blood loss (92 mL), shortest operative time (180 minutes), ICU (1 day) and hospital stays (10 days) while long construct group was observed to have greatest amount of blood loss (355 mL), longest operative time (305 minutes), and ICU stay (2.5 days). Conclusion For patients with MSD, even with predicted poor prognosis on survival prognostic scoring systems, it is possible to improve functional outcomes and quality of life with PPSF keeping surgical morbidity to a minimum. PPSF allows addressing patients with pure spinal instability successfully with least morbidity.