Treatment Strategy for Impending Instability in Spinal Metastases

다국어 초록 (Multilingual Abstract)

Background: Determining surgical management of a spinal metastasis is difficult owing to the involvement of multiple factors.
The spinal instability neoplastic score (SINS) system is a reliable tool to evaluate instability in spinal metastases. The intermediate SINS (scores 7–12) indicates impending instability, which makes it difficult to determine the proper treatment strategy. In this study, we aimed to compare the initial status and treatment outcomes of a conservative group versus an operative group among patients with spinal metastases with an intermediate SINS of 7–12. Further, we evaluated the time for conversion to surgery in patients who had initially undergone conservative treatment and identified the factors associated with the conversion.
Methods: Among the patients with a spinal metastasis with an intermediate SINS of 7–12 from May 2013 to December 2017, those who were followed up for more than 12 months were enrolled in this study. Patients with signs of a neurologic deficit or cord compression at the initial diagnosis were excluded. Finally, 79 patients (47 in the initially conservative group and 32 in the initially operative group) were enrolled in this study. The performance status, Tomita score, and Tokuhashi score were assessed for group comparison. Components of SINS, the Bilsky grade, and radiosensitivity of tumor were evaluated to determine factors associated with conversion to surgery.
Results: Average follow-up was 20.9 months (range, 12–46 months). The demographic variables, primary cancer type, and performance status were not significantly different between the 2 groups. However, the Tomita score was lower in the initially operative group (p = 0.006). The 1-year treatment outcome assessed based on the change in performance status and vertebral height collapse showed a tendency to deteriorate less in the initially operative group. The rate of conversion to surgery in the initially conservative group was 33% in the first year, after which there was little change in the incidence of conversion. When vertebral body collapse was less than 50% or the tumor was located in the semi-rigid region (T3–T10), the need for conversion to surgery increased statistically significantly (p = 0.039 and p = 0.042, respectively).
Conclusions: The rate of conversion to surgery in initially conservatively treated patients was about 33% in the first year. When a tumor is located in T3–T10 and less than 50% vertebral body collapse is present, surgery may be the better choice than conservative treatment.

참고문헌 (Reference)

1 Lee CH, "Which one is a valuable surrogate for predicting survival between Tomita and Tokuhashi scores in patients with spinal metastases? A meta-analysis for diagnostic test accuracy and individual participant data analysis" 123 (123): 267-275, 2015

2 Aoude A, "The revised Tokuhashi score; analysis of parameters and assessment of its accuracy in determining survival in patients afflicted with spinal metastasis" 27 (27): 835-840, 2018

3 Campos M, "The Spine Instability Neoplastic Score : an independent reliability and reproducibility analysis" 14 (14): 1466-1469, 2014

4 Laufer I, "The NOMS framework : approach to the treatment of spinal metastatic tumors" 18 (18): 744-751, 2013

5 Katsoulakis E, "Stereotactic body radiotherapy in the treatment of spinal metastases" 27 (27): 209-217, 2017

6 Arana E, "Spine Instability Neoplastic Score : agreement across different medical and surgical specialties" 16 (16): 591-599, 2016

7 Kostuik JP, "Spinal stabilization of vertebral column tumors" 13 (13): 250-256, 1988

8 Fourney DR, "Spinal instability neoplastic score : an analysis of reliability and validity from the spine oncology study group" 29 (29): 3072-3077, 2011

9 Taneichi H, "Risk factors and probability of vertebral body collapse in metastases of the thoracic and lumbar spine" 22 (22): 239-245, 1997

10 Fisher CG, "Reliability of the Spinal Instability Neoplastic Score(SINS)among radiation oncologists : an assessment of instability secondary to spinal metastases" 9 : 69-, 2014

11 Windhagen HJ, "Predicting failure of thoracic vertebrae with simulated and actual metastatic defects" (344) : 313-319, 1997

12 Zadnik PL, "Outcomes following surgical intervention for impending and gross instability caused by multiple myeloma in the spinal column" 22 (22): 301-309, 2015

13 Harrington KD, "Metastatic disease of the spine" 68 (68): 1110-1115, 1986

14 Weber MH, "Instability and impending instability of the thoracolumbar spine in patients with spinal metastases : a systematic review" 38 (38): 5-12, 2011

15 Leone A, "Instability and impending instability in patients with vertebral metastatic disease" 48 (48): 195-207, 2019

16 Bernard V, "Heterogeneity in treatment response of spine metastases to spine stereotactic radiosurgery within"Radiosensitive"subtypes" 99 (99): 1207-1215, 2017

17 Ulmar B, "Evaluation and modification of the Tomita score in 217 patients with vertebral metastases" 30 (30): 414-418, 2007

18 Terence Tan, "Does Combined Anterior-Posterior Approach Improve Outcomes Compared with Posterioronly Approach in Traumatic Thoracolumbar Burst Fractures?: A Systematic Review" 대한척추외과학회 14 (14): 388-398, 2020

19 Paton GR, "Contemporary treatment strategy for spinal metastasis : the"LMNOP"system" 38 (38): 396-403, 2011

20 박재홍, "Changes in Thoracic Kyphosis and Thoracolumbar Kyphosis in Asymptomatic Korean Male Subjects Aged >50 Years: Do They Progress Above T5, T10, T12, or L2?" 대한척추외과학회 14 (14): 192-197, 2020

21 Whyne CM, "Burst fracture in the metastatically involved spine : development, validation, and parametric analysis of a three-dimensional poroelastic finiteelement model" 28 (28): 652-660, 2003

22 Fisher CG, "A novel classification system for spinal instability in neoplastic disease : an evidence-based approach and expert consensus from the Spine Oncology Study Group" 35 (35): E1221-E1229, 2010

23 Dimar JR 2nd, "A human cadaver model for determination of pathologic fracture threshold resulting from tumorous destruction of the vertebral body" 23 (23): 1209-1214, 1998

24 Aoude A, "A comparison of the modified Tokuhashi and Tomita scores in determining prognosis for patients afflicted with spinal metastasis" 57 (57): 188-193, 2014