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[Microsurgical resection of lumbar intraspinal tumors through paraspinal approach using percutaneous tubular retractor system].

OBJECTIVE
To evaluate the clinical outcomes and operative techniques of microsurgical resection of lumbar intraspinal tumors through paraspinal approach by percutaneous tubular retractor system.


METHODS
A retrospective study was conducted to analyze 21 patients with lumbar intraspinal tumors between November 2011 and February 2014, including Schwannoma (n = 19) and meningioma (n = 2) without lumbar instability on preoperative images. The length of tumors was 0.6-2.0 cm. Tracheal intubation anesthesia was performed prior to microsurgery using percutaneous tubular retractor system through paraspinal approach. Operative duration, blood loss volume, postoperative wound pain duration and hospital stay were analyzed. Creatine phosphokinase (CPK-MM) level was recorded at 1 day preoperatively, 1 day, 3 days and 5 days postoperatively. The scores of Japanese Orthopedic Association (JOA) and visual analog scale (VAS) were analyzed at 1 day preoperatively, 1, 3, 5 days and 6 months postoperatively to evaluate the function status of spinal cord. Computed tomography ( CT) three-dimensional reconstruction of lumbar vertebrae was performed at 1 week postoperatively. Magnetic resonance imaging ( MRI) plain scan and enhanced scan of lumbar vertebrae were conducted preoperatively, 1 week and 6 months postoperatively.


RESULTS
Complete removal of tumors was achieved in all patients without the injuries of spinal cord or nerve root. Postoperative scores of JOA and VAS improved versus preoperative ones (P < 0.05). Level of CPK-MM increased 1 day postoperatively and declined to preoperative level at 5 days postoperatively. And th difference was not statistically significant (P < 0.05). Neither residual tumor nor tumor recurrence was detected by MRI plain and enhanced scans. No postoperative spinal instability was identified by CT three-dimensional reconstruction. And no spinal deformity occurred during a follow-up period of 6-28 months.


CONCLUSION
Microsurgical resection of lumbar intraspinal tumors using percutaneous tubular retractor system through paraspinal approach minimizes the injuries of paraspinal muscles, facet joint, spinous process and ligaments. This technique offers the advantages of mini-invasiveness, shorter hospital stay, rapid recovery and preserved postoperative spinal stability.