Response to Letter to the Editor Concerning “Risk Factors for Postoperative Unfavorable Ambulatory Status After Spinal Surgery for Metastatic Spinal Tumor”

Abstract

e read the letter to the editor regarding our study with great interest and appreciate the authors for this opportunity to respond to it. In the original published article, we addressed the risk factors for postoperative unfavorable ambulatory status: (1) nonambulatory at discharge or (2) a decreased mobility score of the Barthel Index between admission and discharge, using a Japanese nationwide in-hospital database. The surgical procedure of laminectomy alone, as well as male, preoperative nonambulatory status, and preoperative comorbidity, were detected as independently associated factors. 1 Among these, the preoperative ambulatory status was the factor that most strongly affected the postoperative unfavorable ambulatory status (adjusted odds ratio 6.66, P < 0.001). However, as the letter to the editor pointed out, preoperative ambulatory status in each surgical method was not described in the original article. Thus, we have additionally demonstrated the ratio of nonambulatory status in each method in Table 1. There were more preoperative nonambulatory patients in the laminectomy alone procedure and more ambulatory patients in the vertebroplasty when compared with patients in the posterior fusion procedure. While the preoperative ambulatory status varied among the surgical methods (Table 1), the analysis in the original article was performed with adjusting preoperative ambulatory status as well as other confounding factors. Therefore, we consider that the positive association between laminectomy alone procedure and postoperative unfavorable status is valid for discussion.Meanwhile, one of the major limitations of the Diagnosis Procedure Combination (DPC) database is that the clinical data is available only during hospitalization. Therefore, the administration of pre/postoperative chemotherapy/bonemodifying agents or patients' survival after discharge could not be obtained from the DPC database. Furthermore, perioperative estimated blood loss or operative time could not be extracted from the DPC database.In agreement with the letter, we consider that further detailed and longer follow-up research would support or improve the results of our study.