Introduction

Currently, computed tomography (CT)-guided percutaneous needle biopsy is the gold standard diagnostic method for patients with newly diagnosed spinal tumors. Although the advantage of CT-guided spinal biopsy has been well recognized, needle tract seeding (NTS), that tumor contamination occurs on the needle tract during tumor collection, is one of the terrible complications. While complete resection of the needle tract to prevent local recurrence (LR) from NTS is possible in extremity tumors, resection of the biopsy tract is difficult in spinal tumor surgery because of the character of surgical procedure. Therefore, more attention to the LR from NTS has to be paid after CT-guided biopsy of the spine. However, there are very few articles describing NTS after CT-guided biopsy of the spine, and its incidence and risk factors remain vague. The purpose of this study was to investigate LR from NTS after biopsy of the spine.

Methods

The postoperative LR from NTS in consecutive 171 patients who underwent spinal tumor surgery at single institution from Apr 2010 to Apr 2018 were reviewed. Inclusion criteria was as follows; 1) preoperative needle biopsy has been performed, 2) tumor has been surgically removed entirely and 3) postoperative observation period is more than 12 months. No resection of the biopsy tract was performed in all surgeries. LR from NTS was defined as follows; 1) tumor recurrence site was located on biopsy tract and 2) tumor recurrence has no relation with intraoperative tumor exposure.

Results

 Forty-one (20 males and 21 females) patients were included in this study and mean observation period was 50.7 (13-110) months. Twenty cases were primary tumors and 21 cases were metastatic carcinomas. One patient with primary chondrosarcoma had postoperative LR from NTS. The incidence of LR from NTS was 5% (1/20) for primary tumors, 20% (1/5) for primary malignant tumors and 0% (0/21) for metastatic carcinomas.

Case presentation

A 57-year-old woman. Preoperative CT-guided needle biopsy was performed for spinal tumor at T6 and pathological result was grade 2 chondrosarcoma. In surgery, the tumor was entirely removed piece by piece via posterior approach with instrumented fusion. Four months after the surgery, magnetic resonance imaging revealed tumoral lesion suspected LR in the subcutaneous tissue on right back. Pathological result of biopsy was LR of chondrosarcoma. The tumor was located on biopsy tract, where there was no intraoperative tumor exposure, indicating LR from NTS. After resection of the recurrent tumor, the patient has progressed without local re-recurrence within the 3-year postoperative follow-up period.

Conclusion

In this study including 41 cases, one case of primary chondrosarcoma developed LR from NTS. While more attention for LR from NTS is needed after needle biopsy for primary malignant spine tumors, the risk of LR from NTS is expected to be low in spinal metastatic carcinomas that are more common in clinical practice.