The Neurology-Stability-Epidural compression assessment: A new score to establish the need for surgery in spinal metastases
Introduction
Management of spinal metastases has always been challenging [1]. Traditional scores like the ones proposed by Tokuhashi, Tomita, or Bauer have guided decision making in management of patients with spinal metastases for many years, although some limits were already described by their authors [[2], [3], [4]]. First of all, often patients are treated in an emergent setting without a diagnosis and/or a global assessment of the disease. Secondly, subclinical metastases were not taken into account. Furthermore, and more important, the decision for or against surgery was based on survival prognostication alone, but a precise prediction appeared to be limited [5,6]. In the last two decades targeted and biologic therapies dramatically changed survival prognosis in metastatic patients, making these scores unreliable [7,8]. At the same time, the development of Stereotactic Radiosurgery (SRS) and Minimally Invasive Surgery (MIS) techniques imposed a true paradigm shift: abundant evidence has shown that SRS is able to provide significant clinical benefits and high local-control rates regardless, above all, of tumor histology and tumor volume, while MIS techniques allow for limited post-surgical morbidity and quick recovery [9,10]. It appeared progressively clear that surgical indications for spinal metastases could not rely anymore on prognostication of survival, but needed to consider functional recovery/preservation and local control as targets, to pursue a palliative goal. The algorithm proposed by Boriani and Gasbarrini published in 2008 first focused on functional targets of spinal metastases surgery [11]. In 2013 Laufer et al. developed the NOMS framework [9], incorporating new technological tools, surgical techniques, and advances in radiosurgery and systemic treatments [2]. In order to better provide a comprehensive assessment of new concepts for the treatment of spinal metastases the term NOMS included the four cornerstones of management: Neurologic, Oncologic, Mechanical, and Systemic assessments. Surgery was strongly suggested in case of instability, as evaluated with the SINS score, and/or high grade spinal cord compression with neurological deficits (or without deficits in radioresistant tumors). The term “separation surgery” represents the need for a circumferential decompression of the spinal cord and the nerve roots in order not only to preserve or restore neurological functions, but also to create an ablative target for SRS and a safe distance between the tumor and the spinal cord, therefore optimizing radiation treatment and allowing for a safe delivery of appropriate doses for local control (>15 Gy) [9]. It should be assumed, in these cases, that SRS should be available and the tumor considered radioresistant for conventional External Beam Radiation (cEBRT) like many solid tumors. Other similar algorithms were developed focusing on the same issues [12].
The aim of this study was to translate new evidence-based frameworks in a practical and reliable score for surgeons, radiation oncologists, and oncologists, that could establish the need for surgery in the evaluation of a patient with spinal metastases even in the absence of an histological diagnosis and regardless of the available technology.
Section snippets
Study participants
A detailed retrospective evaluation was performed. Every patient that received a surgical procedure or conservative treatment after neurosurgical evaluation for spinal metastases at the authors’ institution from January 2015 to May 2019 was considered. Patients were usually treated according to the NOMS framework principles [9] and individual patient preferences.
Data recorded for each case included: sex, age, type of tumor, time of occurrence of the spinal metastases, spinal level of the
Results
A total number of 283 patients was reviewed but only 145 of them (91 M, 54 F) were included in the study after implementation of the inclusion and exclusion criteria. The most common reason for exclusion was the lack of all needed data for the analysis (82/138). The absence of a 3 months follow-up was recorded in 18 cases but 16 of them were graded as ASA > 3 and/or ECOG > 2. Mean age was 63.8 years (range 22–68). Demographics and descriptive data are summarized in Table 1. The most common
ASA and ECOG
Assuming the general improvement of survival and the unpredictability of quoad vitam prognosis, a reliable prognostication of survival should be made only to target the quality of treatment and not to justify the need for it anymore. Given this, patients in poor general conditions, with a very low life expectancy (e.g. <2 months) or with a very high anesthesiological risk should not be considered suitable for surgery, because chances to ensure the palliative aim of spinal metastasis surgery are
Strengths of the score
This is a reliable, practical, and manageable score for surgeons, oncologists, and radiation oncologists able to concretely define patients who would benefit from surgery. The score has been thought to address functional needs of patients, and can be effective even in the absence of a histological diagnosis of the type of tumor. This could help in many cases of unknown diagnosis when a prompt decision should be undertaken in emergent patients. For the same reason, hematopoietic malignancies
Limitations of the score and of the study
The proposed study analysis carries limits given by its retrospective nature, but a prospective validation could raise ethical issues. The score does not provide indications on the type of treatment needed, because the goal of this study was to provide a tool able to establish the need for surgery and not its modality. Furthermore, there is still no widespread agreement among surgeons and in the literature on the specific type of treatment needed and SRS is actually often still not available in
Conclusion
Functional outcomes of the study group showed that the proposed NSE score could represent a practical and reliable tool to establish the need for surgery. Agreement between the score and the performed treatments resulted in better clinical outcomes, when compared with patients without agreement. Further validation is needed with a larger number of patients and to assess reproducibility among surgeons, radiation oncologists, and oncologists.
Declaration of Competing Interest
The authors have no conflict of interest to disclose.
CRediT authorship contribution statement
Fabio Cofano: Conceptualization, Methodology, Writing - original draft, Writing - review & editing. Giuseppe Di Perna: Data curation. Francesco Zenga: Data curation, Supervision. Alessandro Ducati: Conceptualization. Bianca Baldassarre: Data curation. Marco Ajello: Investigation. Nicola Marengo: Investigation. Luca Ceroni: Formal analysis. Michele Lanotte: Writing - review & editing, Supervision. Diego Garbossa: Data curation, Supervision.
Acknowledgments
This study was supported by Ministero dell’Istruzione, dell’Università e della Ricerca—MIURproject “Dipartimenti di eccellenza 2018–2022”. The first author of this paper (F.C.) is extremely grateful to Maurizio, Jessica and Sofia Grace Anglani for their inestimabile support and help throughout the crucial steps of this research.
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