compression should be considered rst when deciding on a surgical approach. Indications for resection of thoracolumbar tumors generally include intractable pain, impending spinal insta­bility, progressive compression of the spinal cord or cauda equina by bony elements (irrespective of radiosensitivity of the tumor), and symptom­atic compression of neural structures by radio­resistant tumors [4]. Furthermore, the predicted oncological survival based on clinical character­istics (i.e., Tokuhashi score [19–21]) and the probability of neurological recovery after resec­tion and decompression should be taken into account individually. For instance, a recent sys­tematic review reported that, although supported by low-quality evidence, the duration of ambula­tion loss and severity of neurologic decit (i.e., muscle strength and bladder function) were the greatest predictors of postoperative neurological recovery in patients with metastatic epidural spi­nal cord compression [22].

Additionally, when using posterior approaches to the lumbar spine, particularly at or below L2, the nerve roots cannot be sacriced without a motor decit, which makes it difcult for us to insert vertebral body replacement (VBR) devices of sufcient height. Although expandable cages have been increasingly used for this reason, it can still be a substantial challenge to access this space, obtain an adequate correction of any kyphotic deformity, and restore the full height of

Recently, the Spinal Instability Neoplastic Score (SINS) scoring system was proposed by the Spinal Oncology Study Group (SOSG), which allows for quantication of the potential spinal instability of patients with spinal tumors [27] and stratication of patients who may benet from stabilization [28, 29]. Briey, the SINS system takes a wide variety of relevant factors into con­sideration, such as tumor location (junctional, mobile spine, semirigid, and rigid), mechanical pain, bone lesion (lytic, mixed, and blastic), radio-

In terms of VBR selection, Zhou etal. biome­chanically compared PEEK cage-rod constructs with titanium cage-rod constructs in the setting of an L1 corpectomy and demonstrated that the PEEK cage-rod construct allowed more motion compared to the titanium cage-rod construct but resulted in higher stability in exion and lateral bending without preloading and exion and extension under the preloading condition [43]. Conversely, a systematic review by Li etal. main­tained that there was no clinically signicant dif­ference between these two constructs [44]. To study the effects of different VBRs on subsid­ence, Pekmezci etal. evaluated ten human thora­columbar spines (T10–L2, L3–L5) biomechanically invitro after a single-level cor­pectomy and reconstruction with an expandable or xed cage plus anterior dual-rod instrumenta­tion and demonstrated that, in spite of larger sur­face contact area, expandable cages had a tendency for more frequent subsidence than xed cages and also that, in the presence of edge load­ing, as is clinically observed in the setting of hyperlordotic cages, there was an even higher risk of subsidence and intraoperative fracture at the moment of deployment [45]. This nding is compatible with other in vitro/in silico studies and several prospective/retrospective clinical series reported in the literature [46–48]. Additionally, Eleraky etal. described their retro­spective clinical series of 16 patients with PMMA and 16 patients with expandable cages after cor­pectomy for tumors in thoracolumbar regions and concluded that both approaches allow for adequate correction of the kyphotic deformity and spinal stabilization with comparable func­tional and performance status outcomes [49]. In short, currently there is no scientic or clinical evidence which denitively supports one specic type of VBR device.