Neurological outcomes after surgery for spinal metastases in symptomatic patients: Does the type of decompression play a role? A comparison between different strategies in a 10-year experience

Abstract

Introduction: The impact of neurological deficits plays a role of inestimable importance in patients with a neoplastic disease. The role of surgery for the management of symptomatic spinal cord compression (SSCC) cannot be overemphasized, as surgery represents often the first and paramount step in patients presenting with motor deficits. The traditional paradigm of simple bilateral laminectomy for the treatment of spinal cord compression has been reviewed. The need to achieve a proper circumferential decompression of the spinal sac has been progressively highlighted in combination with the development of the more comprehensive and multidisciplinary concept of separation surgery.

Objective: The aim of this paper is to analyze different strategies of decompression, while evaluating whether circumferential/anterior decompression is able to guarantee a better control and restoration of neurological functions in patients with motor impairment, if compared to traditional posterior decompression.

Materials and methods: This is a retrospective observational study investigating symptomatic patients that underwent surgical treatment for spinal metastases at author's Institutions from January 2010 to June 2019. Data recorded concerned patient demographics, tumor histology, peri-operative and follow-up neurological status (ASIA), ambulation ability, stability (SINS), grade (ESCC) and source of epidural compression and type of decompression (anterior/anterior-lateral (AD); posterior/posterior-lateral (PD/PDL); circumferential (CD)).

Results: A total number of 84 patients was included. AD/CD patients showed higher chance of neurological improvement and reduced rates of worsening compared to PD/PLD group (94.1%/100% vs 60.4%; 11.8% vs 45.8% respectively). Univariate logistic regression identified immediate post-operative improvement to be a significative protective factor for worsening at last follow-up. Stratifying patients for site of compression and considering anterior and circumferential groups, immediate post-operative neurological improvement, was mostly associated with AD and CD (p 0.011 and 0.025 respectively). Walking at last follow up was influenced by post-operative maintenance of ambulation (p 0.001).

Conclusion: The necessity to remove the epidural metastatic compression from its source should be considered of paramount importance. Since the majority of spinal cord compression involves firstly the ventral part of the sac, CD/AD are associated with better neurological outcomes and should be achieved in case of circumferential or anterior/anterolateral compression.

Keywords: A-lSCC, antero-lateral spinal cord compression; AD, anterior decompression; ASCC, anterior spinal cord compression; ASIA, American Spinal Injury Association Impairment Scale; CD, circumferential decompression; CSCC, circumferential spinal cord compression; Circumferential decompression; ESCC, epidural spinal cord compression scale; HRQoL, health-related quality of life; IONM, intraoperative neurophysiological monitoring; MIS, minimally invasive surgical; Metastatic epidural compression; Minimal invasive spine surgery; P-lSCC, postero-lateral spinal cord compression; PD, posterior decompression; PLD, postero-lateral decompression; PSCC, posterior spinal cord compression; RT, radiotherapy; SINS, spinal instability neoplastic score; SSCC, symptomatic spinal cord compression; Separation surgery; Spinal metastases; cEBRT, conventional external beam radiation therapy.

Fig. 1

Thoracic lung cancer metastasis (A-G). A 63 years old woman presented to the authors attention with mechanical back pain. (A) Sagittal T2w MRI and (B) CT scan showing an osteolytic T8 metastatic lesion with ventral Bilsky grade 2 epidural compression and mechanical instability (SINS score 12). (C) A navigated CD was performed and (E) 3D endoscope was used to better achieve ventral decompression of the dural sac; (D) one level above and below the pathological vertebra was fixed using carbon fiber/PEEK system. (F) Post-operative myelo-CT scan showing CD with restored CSF space around the cord (separation surgery). (G-H) Post-operative CT scan showing CD (H) and partial vertebral body removal without the need for anterior column reconstruction.

Fig. 2

Cervical thyroid cancer metastasis (A-N). A 57 years old woman with history of thyroid cancer, presented to the authors attention with a huge cervical mass arising from C3 vertebral body. (A-C) Pre-operative T2w MRI showing the mass that arises from C3 vertebral body, involving C4 and C5 vertebras (A,C) with lateral extension toward the right side and right vertebral artery encasement; a Bilsky grade 3 epidural compression is observed and SINS score was 12 (B). (D-E) 3D reconstruction model showing the close relationship between the mass, the vertebral artery, the larynx and esophagus. (F-H) A two steps surgical strategy was adopted: firstly, patient underwent posterior cervical approach with the aim to remove the postero-lateral portion of the tumor and to decompress the medulla and cervical roots (F); an occipital-cervical-thorax fixation until T2 was also performed (H); lastly an anterior cervical approach was performed, completing tumor removal and performing a C3-C5 corpectomies; (G) then a then a PEEK interbody cage interbody cage and anterior cervical plate were used for anterior stabilization. (I-L-M) Post-operative CT scan showing the extent of resection and the fixation construct. (N) Post-operative T2w MRI showing tumor removal and spinal cord decompression.