Results of posterior surgery with intraperative radiotherapy for spinal metastasis

Abstract

Purpose of study: To improve the neurological recovery and to increase the local control rate in cases with spinal metastasis, we have been conducting a clinical trial of decompressive surgery combined with intraoperative radiotherapy (IORT) since 1992. We report the results of neurological recovery in cases who received IORT.Methods used: After conventional posterior decompression, patients are transferred from the operating room to the radiotherapy room (Fig. 1) . The rectangular electron cone (applicator) is placed in the surgical field (Fig. 2) . The appropriate cone size is chosen to cover the lesion, and a lead shield is put in the middle of the cone to protect the spinal cord from the electron beam (Fig. 3) . Simulation study shows that the beam covers the area anterior to the dura (Fig. 4) . Electron beams generated by Hitachi Microtron (Hitachi Company, Tokyo, Japan) are used. The delivered dose is approximately 20 Gy, which equals 40 to 50 Gy of external radiation. After IORT, the patient is transferred back to the operating room, where spinal instrumentation is performed if necessary.of findings: Between November 1992 and December 2001, 133 cases (117 patients) were treated with IORT in the Tokyo Metropolitan Komagome Hospital. Eighty cases (75 patients) of them were reviewed, who received only posterior surgery for spinal paresis (not cauda equinaparesis) resulting from spinal metastasis (not primary spinal tumors). As for primary sites, there were 13 breast cases, 12 lung, 9 colon, 8 thyroid, 7 prostate, 6 kidney, 5 liver, 4 multiple myeloma, 3 malignant lymphoma and 13 miscellaneous. Sixty-three patients died in 2 weeks to 63 months after IORT (mean survival time, 11 months). Seventeen patients were still living after a follow-up period of 1 to 65 months (mean, 20 months). None of the cases showed neurological deterioration immediately after IORT. Of 70 cases with motor weakness, 58 cases (83%) attained at least one-level improvement according to Frankel's classification. Of 59 cases unable to walk before IORT, 45 cases (76%) gained walking ability. Of 14 cases unable to walk after IORT, 13 cases (93%) attained at least one-level improvement according to manual muscle testing. Of 73 patients, who survived more than 3 months after IORT, 2 patients (3%) showed neurological deterioration as a result of local recurrence 3 to 16 months after IORT. The other remaining 71 patients had no signs of local recurrence during the follow-up period. There was no case with surgical wound infection.Relationship between findings and existing knowledge: The rate of neurological recovery in this method is 83%, better than those of other conventional methods in previous reports (56% to 70%). The rate of local recurrence in our method is 3%, better than those of other methods (6% to 28%).Overall significance of findings: Decompressive surgery with IORT for spinal metastasis shows excellent results for local control and improves the quality of life of the patients.Disclosures: No disclosures.Conflict of interest: No conflicts.