The Techniques And Evaluation Of Microsurgical Resection Of The Intradural Extarmedullary Tumors Through Hemilaminectomy

Objective: To investigate the microsurgical techniques of theexcision of the intradural extramedullary tumors throughhemilaminectomy and to illustrate its clinical effect.Methods: The clinical data of16patients （7men，9women）with intradural extramedullary tumors treated in our hospital fromJanuary2009to December2011wewe retrospectively analyzed.The average age was49years，ranging from34-72years. Themedical history ranged from7months to3years with an average of15.7months. The intradural extramedullary tumors located at thecervical level in3patients, thoracic in4patients, thoracico-lumbarin9patients. All patients had various degrees of symptoms andsigns caused by spinal cord compression. All patients received MRIexaminations preoperatively and showed masses in the spinalcanal. MRI images should comprise the precise spinal segment ofthe tumor. All patients were received general anesthesia with proneposition. Syringe needle markers were inserted into spinousprocess under the fluoroscopic of the C-arm X-ray machine toassure accurate positioning. Microscope was placed to start themicrosurgical excision and used bipolar coagulation to do the hemostasis. Negative pressure drainage indwelled in the laminaand stitched up the incision.14patients underwenthemilaminectomy while2patients were treated with laminectomyduring operation. The clinical effect of hemilaminectomy wasevaluated based on Frankel grade.Results: The mean bleeding volume was300mL (150-500mL)and the mean duration of operation was140min (90-200min). Themean bleeding volume of the patients underwent hemilaminectomyand laminectomy was275mL（150～350mL）and475mL (450mLand500mL) respectively. The maximum volume of the tumor was4cm×1.5cm×l.5cm，while the minimum one was1.5cm×1.0cm×l.0cm. There were neurinoma in11patients，meningioma in4cases and neurofibroma in1case. Cerebrospinal fluid leakageoccurred in one patient. No surgical wound infection or spinalinstability was seen in our group.3cases ameliorated from Frankelgrade B to C;5cases of Frankel grade C recovered to grade D;7cases of Frankel grade D was improved to grade E．All the patientswere followed up from6to40months with an average of23.7months. There were no local recurrences or spinal secondarydeformities, and spinal stabilities were satisfactory. All the patientsachieved remission of symptoms.Conclusion: The advantages of the approach are minor invasion，less bleeding，and utmost retaining to the spinal stability.We hold that IDEM tumors located on one side is the bestindication for hemilaminectomy. The outcome of the excision of theintradural extramedullary tumors through hemilaminectomy issatisfactory in general． And we should strictly master indicationsand excise the tumor as thoroughly as possible while notaggravating the spinal cord injury.