Adverse events (AEs) are still a major problem in spinal surgery, despite advances in surgical techniques, innovative technologies available and the introduction of checklist and predictive score systems aimed at reducing surgical complications. We previously analysed the results of the introduction of the WHO Safety Surgical Checklist (SSC) in our Institution, comparing the incidence of complications between two periods: from January to December 2010 (without checklist) and from January 2011 and December 2012 (with checklist), in order to assess the checklist effectiveness. The sample size was 917 patients with an average of 30 months of follow-up. Complications were observed in 107 patients (11.6%) among 917 spinal surgery procedures performed, with 159 (17.3%) complications in total. The overall incidence of complications for trauma, infectious pathology, oncology, and degenerative disease was 22.2%, 19.2%, 18.4%, and 15.3%, respectively. We observed a reduction of the overall incidence of complications following the introduction of the WHO Surgical Checklist: in 2010 without checklist, the incidence of complications was 24.2%, while in 2011 and 2012, following the checklist introduction, the incidence of complications was 16.7% and 11.7%, respectively (mean 14.2%) (p<0.0005). Thus, the SSC appeared to be an effective tool to reduce complications in spinal surgery and we proposed to extend the use of checklist system also to the pre-operative and post-operative phases in order to further reduce the incidence of complications. We also believe that a correct capture and classification of complications is fundamental to generate a clinical decision support system aimed at improving patients’ safety in spinal surgery. In the period between January 2017 and January 2018 we prospectively recorded the adverse events and complications of patients undergoing spinal surgery in our department, without using any collection system. Then we retrospectively recorded the intraoperative and postoperative adverse events of surgically treated patients during the same one-year period, using the SAVES v2 system introduced by Rampersaud and collaborators (Rampersaud YR et al. J Neurosurg Spine 2016 Aug; 25 (2): 256-63) to classify them. In the one-year period from January 2017 to January 2018 a total of 336 patients underwent spinal surgery: 223 for degenerative conditions and 113 for spinal tumors. Comorbidities were collected (Charlson Comorbidity Index [CCI]). Overall, a higher number of adverse events (AEs) was recorded using SAVES compared to the prospective recording without the use of any capture system and the increased number was statistically significant for early postoperative AEs (138/336 vs 44/336, p<0.001). 210 adverse events were retrospectively recorded using the SAVES system (30 intraoperative adverse events, 138 early postoperative and 42 late postoperative adverse events). 99 patients (29.5%) on the cohort had at least one complication. Furthermore, the correlation between some risk factors and the onset of complications or the prolonged length of stay was statistically analyzed. The risk factors taken into account were: age, presence of comorbidities (CCI), ASA score, previous surgery at the same level, type of intervention, location of the disease, duration of the surgery. In particular, the duration of the surgery (more than 3 hours) and the presence of previous surgeries resulted to be risk factors for complications in multivariate analyses

In case of spine tumors, when en bloc vertebral column resection (VCR) is indicated and feasible, the segmental defect should be reconstructed in order to obtain an immediate stability and stimulate a solid fusion. The aim of this study is to share our experience on patients who underwent spinal tumor en bloc VCR and reconstruction consecutively. En bloc VCR and reconstruction was performed in 138 patients. Oncological and surgical staging were performed for all patients using Enneking and Weinstein-Boriani-Biagini systems accordingly. Following en bloc VCR of one or more vertebral bodies, a 360° reconstruction was made by applying posterior instrumentation and anterior implant insertion. Modular carbon fiber implants were applied in 111 patients, titanium mesh cage implants in 21 patients and titanium expandable cages in 3 patients; very recently in 3 cases we started to use custom made titanium implants. The latter were prepared according to preoperative planning of en bloc VCR based on CT-scan of the patient, using three dimensional printer. The use of modular carbon fiber implant has not leaded to any mechanical complications in the short and long term follow-up. In addition, due to radiolucent nature of this implant and less artifact production on CT and MRI, tumor relapse may be diagnosed and addressed earlier in compare with other implants, which has a paramount importance in these group of patients. We did not observe any implant failure using titanium cages. However, tumor relapse identification may be delayed due to metal artifacts on imaging modalities. Custom- made implants are economically more affordable and may be a good alternative choice for modular carbon fiber implants. The biocompatibility of the titanium make it a good choice for reconstruction of the defect when combined with bone graft allograft or autograft. Custom made cages theoretically can reproduce patients own biomechanics but should be studied with longer follow-up

Summary Statement. Tandem stenosis is a prevalent condition in an Asian population with the narrowest cervical canal diameters and risk factors include advanced age and increased levels of lumbar canal stenosis. Introduction. Tandem spinal stenosis (TSS) is defined as patient with concomitant spinal canal stenosis found in both cervical (C) and lumbar (L) spinal region. Few studies have reported the incidence of TSS is ranged from 5–25%, but these are all noncomparative, small cohort studies. To the best of author knowledge this is the 1st study aims to compare the prevalence of TSS and its risk factors of development in a large multiracial Asian population. Methods. A retrospective review of all mid-sagittal T2MRI whole spine image was carried out at a University hospital in year 2007. Patients with spinal tumour, fracture and congenital stenosis were excluded. Spinal stenosis was defined as canal diameter of ≤10mm, measured from the posterior cervical vertebral/disc wall to anterior surface of the corresponding lamina. Patients were divided into 4 groups, no stenosis(NS), lumbar stenosis only(LS), cervical stenosis only(CS) and TSS. Patients’ demographics, race, co-morbidities and lumbar radiological report data were examined. Potential risk factors for the development of TSS were analyzed using SPSS software. Results. 926 (479 male, 447 female) patients with average age 50 (20–96) yrs were studied. Cervical canal diameters (mm) in TSS patients were the narrowest among the 4groups with C2/3 disc: 11.6, C3/4: 9.7, C4/5: 9.4, C5/6: 8.9, C6/7: 10.0 and C7T1: 11.4mm. The incidence of TSS was 26.2%. The prevalence of TSS in Chinese was 30.7%, Indian 12.5%, Malay 22.5%. The TSS prevalence in patients with 1 level lumbar canal stenosis was 12.5%, 2 levels lumbar stenosis was 6.4% and 3 levels was 4.1%. Multivariate analysis showed patients aged between 40–59 yrs (p=0.000, Exp(B):5.8, 95%CI 2.8–12.0), aged > 60yrs (p=0.000, Exp(B): 10.5, 95%CI 4.8–22.9), Chinese race (p=0.008, Exp(B): 2.5, 95%CI 1.3–4.9), patients with 1 level lumbar stenosis (p=0.000, Exp(B): 63.3, 95%CI 29.2–137.3), 2 levels lumbar stenosis (p=0.000, Exp(B): 67.7, 95%CI 29.4–155.7) and 3 levels lumbar stenosis (p=0.000, Exp(B): 106.6, 95%CI 43.6–260.5) are statistical significant risk factors for TSS development. Conclusion. The incidence of TSS was 26.2%. TSS patients have the narrowest cervical canal measurements among the studied groups. The prevalence of TSS in Chinese is the highest (30.7%). Patients advancing in age or have increased levels of lumbar canal stenosis are at risk of developing TSS

Summary. This is the first ever study to report the successful elimination of malignant cells from salvaged blood obtained during metastatic spine tumour surgery using a leucocyte depletion filter. Introduction. Catastrophic bleeding is a significant problem in metastatic spine tumour surgery (MSTS). However, intaoperative cell salvage (IOCS) has traditionally been contraindicated in tumour surgery because of the theoretical concern of promoting tumour dissemination by re-infusing tumour cells into the circulation. Although IOCS has been extensively investigated in patients undergoing surgery for gynaecological, lung, urological, gastrointestinal, and hepatobiliary cancers, to date, there is no prior report of the use of IOCS in MSTS. We conducted a prospective observational study to evaluate whether LDF can eliminate tumour cells from blood salvaged during MSTS. Patients & Methods. After Institutional Review Board (IRB) approval, 21 consecutive patients with metastatic spinal tumours from a known epithelial primary (defined as originating from breast, prostate, thyroid, renal, colorectal, lung, nasopharyngeal) who were scheduled for MSTS were recruited with informed consent. During surgery, a IOCS device (Dideco, Sorin Group, Italy) was used to collect shed blood from the operative field. Salvaged blood was then passed through a leucocyte depletion filter (RS1VAE, Pall Corporation, UK). 15-ml specimens of blood were taken from each of three consecutive stages: (i) operative field prior to cell saver processing (Stage A); (ii) transfusion bag post-cell saver processing (Stage B); (iii) filtered blood after passage through LDF (Stage C). Cell blocks were prepared by the pathology department using a standardised laboratory protocol. From each cell block, 1 haematoxylin and eosin (H&E) slide, and 3 slides each labelled with one of the following monoclonal mouse cytokeratin antibodies AE1/3, MNF 116 and CAM 5.2 were prepared. The cytokeratin antibodies are highly sensitive and specific markers to identify tumour cells of epithelial origin. These slides were read by one of two consultant pathologists who were provided full access to information on operative notes, but were blinded to the actual stages from which the slides were derived. Results. One case was excluded when the final diagnosis was revised to infection instead of metastatic spine tumour. Of the remaining cases, 7/21 tested positive for tumour cells in Stage A, 2 positive in Stage B. No specimen tested positive for tumour cells in Stage C. In 5 cases, posterior instrumentation without tumour manipulation was performed. Discussion/Conclusion. In this first-ever study of cell saver use in spine tumour surgery, we prove that leucocyte-depletion filters (LDF) can effectively eliminate tumour cells from blood salvaged during MSTS. It is now possible to conduct a clinical trial to evaluate IOCS-LDF use in MSTS. Our results are consistent with published results of similar studies performed on IOCS and LDF use outside the field of orthopaedic surgery. Spinal metastases originate from a myriad of primary cancers across various organ systems. If LDF can remove tumour cells from blood salvaged during surgery for spinal metastasis of different histological origin, then the finding can likely be extrapolated to several other fields of surgery where IOCS and LDF have not yet been attempted such as: neurosurgery, otolaryngology and general musculoskeletal oncology. Our results form a proof-of-concept for a paradigm shift in thinking regarding autotransfusion during spine tumour surgery

Summary. Our meta-analysis showed that pooled mean blood loss during spinal tumour surgeries was 2180 ml. Standardised methods of calculating and reporting intra-operative blood loss are needed as it would be beneficial in the pre-operative planning of blood replenishment during surgery. Introduction. The vertebral column is the commonest site of bony metastasis, accounting for 18,000 new cases in North America yearly. Patients with spinal metastasis are often elderly, have compromised cardiovascular status, poor physiological reserve and altered immune status, all of which render them more susceptible to the complications of intra-operative blood loss and associated transfusion. Currently no consensus exists regarding the expected volume of blood lost during metastatic spine tumour surgery with various papers quoting anywhere between 1L to 6L. Knowledge of the expected blood loss prior to surgery however is important as it facilitates pre-operative planning, intra- and post-operative management of fluid balance and blood transfusion. We conducted a meta-analysis of published literature on spine tumour surgery to answer the question: “What is the expected blood loss in major spinal tumour surgery for metastatic spinal disease?”. Methods. A comprehensive online search of the English literature using Medline, Embase, and the Cochrane Central Register of Controlled Trials was performed. We included articles published from 31 January 1992 until 31 January 2012. This initial online search yielded 98 relevant articles. Two senior investigators independently reviewed all abstracts. The full text of articles that were deemed eligible for further consideration obtained and reviewed. Eighty five articles were excluded at this stage, largely due to lack of clear blood loss data, leaving 13 eligible articles. A hand search of the reference lists of relevant articles yielded 5 more articles. A total of 18 articles were included in the final meta-analysis of blood loss data. Disagreements regarding eligibility of articles for analysis were resolved by consensus. Selected articles for final analysis were independently graded according to the Centre for Evidence-Based Medicine (CEBM) Levels of Evidence. We evaluated the possibility of publication bias by obtaining a funnel plot (created by plotting the sample size against the effect estimate). The Egger's regression asymmetry test was used to assess the existence of publication bias. Results. Eighteen selected articles had a total of 785 patients who had undergone major spine tumour surgery for metastatic spinal disorders. The pooled estimate of the blood loss occurring during spinal tumour surgeries was calculated to be 2180ml (95%CI: 1805–2554ml). Apart from two studies which reported significant mean blood loss of more than 5500 ml, the resulting funnel plot suggested absence of publication bias. This was confirmed by Egger's test which did not show any small-study effects (p=0.119). However, there was strong evidence of heterogeneity between studies with I2=90% (p<0.001). Conclusions. The expected blood loss of a patient undergoing major surgery for spinal tumour constitutes more than a third of the circulating blood volume in a typical cancer patient with significantly impaired physiological reserve. Moreover, cases of catastrophic blood loss exceeding 5L exist in almost every series evaluated in this paper, with some reaching as much as 17–18L. Blood loss is a significant problem during spine tumour surgery and concerted effort is needed to address it

The aim of this biomechanical study was to investigate the role of the dorsal vertebral cortex in transpedicular screw fixation. Moss transpedicular screws were introduced into both pedicles of each vertebra in 25 human cadaver vertebrae. The dorsal vertebral cortex and subcortical bone corresponding to the entrance site of the screw were removed on one side and preserved on the other. Biomechanical testing showed that the mean peak pull-out strength for the inserted screws, following removal of the dorsal cortex, was 956.16 N. If the dorsal cortex was preserved, the mean peak pullout strength was 1295.64 N. The mean increase was 339.48 N (26.13%; p = 0.033). The bone mineral density correlated positively with peak pull-out strength.

Preservation of the dorsal vertebral cortex at the site of insertion of the screw offers a significant increase in peak pull-out strength. This may result from engagement by the final screw threads in the denser bone of the dorsal cortex and the underlying subcortical area. Every effort should be made to preserve the dorsal vertebral cortex during insertion of transpedicular screws.