Bone metastases from chondroblastoma: a rare pattern of metastatic disease in an adult.

Chondroblastoma is a rare benign tumor, typically presenting in the first two decades. Systemic metastases in chondroblastoma are extremely rare and it is the rarity of these metastases which lead the World Health Organisation to re-classify this lesion from "intermediate" to "benign" in its updated classification of bone tumors in 2020. We present an unusual case of a 55 year-old male patient who presented with multiple FDG-avid bone lesions on a background of conventional chondroblastoma of the rib excised at another institution 11-years previously. Two of these lesions were also histologically-proven as conventional chondroblastoma at biopsy. This case highlights that, although rare, metastases can be seen in patients with chondroblastoma. To our knowledge, this is the only case with an unusual pattern of metastases limited to bone.

A perioperative overview of a retained surgical swab in spinal surgery: Case report and prevention protocol.

INTRODUCTION: Retained wound swabs although classified as a 'never event' and well documented in many surgical specialties are uncommon in spinal surgery. The aim of this article is to highlight the perioperative circumstances of an incident of a retained surgical swab and present a prevention protocol, in an attempt to eliminate its incidence. CASE REPORT: The perioperative management of a 53-year-old male undergoing spinal surgery in whom a surgical swab was retained is reported. In addition to existing safety procedures such as the World Health Organization checklist, a Retained Surgical Swab-Prevention Protocol was implemented in our hospital and is presented to eliminate the occurrence of this 'never event' occurring again. CONCLUSION: Retained surgical swabs or instruments are rare in spinal surgery occurring mostly in the lumbar spine, during emergency and prolonged procedures in patients with high body mass index. Maintaining a high index of suspicion and utilising a prevention protocol will prevent further harm to the patient.

Blood loss in total en bloc spondylectomy for primary spinal bone tumours: a comparison of estimated blood loss versus actual blood loss in a single centre over 10 years.

Background: Total en bloc spondylectomy (TES) is a widely accepted surgical technique for primary spinal bone tumours but is frequently accompanied by substantial peri-operative blood loss. Prior studies have reported estimated blood loss (EBL) can reach up to 3,200 mL. The aim of this study is to estimate the blood loss during TES procedures performed in the last ten years at our tertiary referral centre and compare EBL with actual blood loss (ABL). Methods: We performed a retrospective review of all cases managed surgically with TES referred to our centre between 2005 and 2015. We recorded the oncological characteristics of each tumour and surgical management in terms of resection margins, operative duration and instrumentation. Data relating to peri-operative blood loss was also recorded including an estimation of total blood loss, the use of cell salvage where applicable and transfusion rates. Results: A total of 21 patients were found to meet our inclusion criteria. There were 11 men and 10 women, with a median age of 40 years. The mean total ABL was 3,310 mL. Total operation time ranged from 6.53 to 19.7 h. Compared to ABL, in 59% of cases EBL had been underestimated by an average of 78% by volume. The EBL of the remaining 41% cases had been overestimated by 43%. This was not statistically significant (P=0.373). Cell salvage was used in 62% patients with a mean blood loss of 2,845 mL (884-4,939 mL) and transfusion of 3.8 units (0-12 units) versus 4,069 mL (297-8,335 mL) and 9.3 units (0-18 units) in those not managed with cell salvage. There was no significant difference in ABL between the cell salvage and non-cell salvage groups. Conclusions: We report one of the largest case series in TES for primary bone tumours. EBL is not a reliable predictor for ABL. A large blood loss should be anticipated and use of cell salvage is recommended.

En Bloc Resection of Tumors of the Lumbar Spine: A Systematic Review of Outcomes and Complications.

BACKGROUND: The literature on total en bloc spondylectomy (TES) of bone tumors of the lumbar spine is sparse and heterogeneous. Therefore, the aim was to systematically pool the data from the published studies to quantitatively summarize the morbidity and mortality and to identify factors associated with favorable outcomes and complications. METHOD: A systematic literature search for studies with individual patient-level data was conducted using specific medical subject heading(MeSH) terms. The outcome measures assessed included complications, tumor recurrence, survival, and function. Individual patient data were pooled from all the studies and quantitatively analyzed to assess the association of different factors with outcomes and complications. RESULTS: Twelve studies were included in this review with a total of 145 TES cases. Of all patients, 50% had at least 1 reported complication post surgery and this was associated with advancing age (OR 1.04, P < 0.001), metastatic disease (OR 5.61, P < 0.001), and adjuvant chemo and/or radiotherapy (OR 20.3, P = 0.001). Intralesional excision (OR 5.2, P = 0.01) and primary malignant tumors (OR 3.3, P = 0.02) were associated with a high recurrence rate. However, the surgical approach was not associated with differences in survival (P = 0.874) or recurrence (P = 0.525) rates. L5 tumor resection was associated with excessive bleeding. Postoperatively, there was an overall improvement in the Frankel grades in most patients. CONCLUSION: TES is associated with high rates of complications especially in association with primary malignant and metastatic diseases. However, the number of publications on this topic remain scarce and heterogeneous. Hence, there is a need for standardization in the reporting of the outcomes and complications to help with decision-making and consenting for this procedure.

Cement augmentation of odontoid peg fractures: the effect of cement volume and distribution on construct stiffness.

PURPOSE: The cement augmentation of a conventional anterior screw fixation in type II odontoid process fractures for elderly patients significantly increased stiffness and load to failure under anterior-posterior load in comparison with non-augmented fixation. The amount and quality of bone cement are usually taken ad hoc in clinical practise. In this study, we wanted to clarify the role of bone cement amount and its quality to the stiffness of odontoid and vertebrae body junction. METHODS: Finite-element method was used to achieve different scenarios of cement augmentation. For all models, an initial stiffness was calculated. Model (1) the intact vertebrae were virtually potted into a polymethylmethacrylate base via the posterior vertebral arches. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. (2) The odontoid fracture type IIa (Anderson-D'Alonzo classification) was achieved by virtual transverse osteotomy. Anterior screw fixation was virtually performed by putting self-drilling titanium alloy 3.5 mm diameter anterior cannulated lag screw with a 12 mm thread into the inspected vertebrae. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. The vertebrae body was assumed to be non-cemented and cemented with different volume. RESULTS: The mean cement volume was lowest for body base filling with 0.47 ± 0.03 ml. The standard body filling corresponds to 0.95 ± 0.15 ml. The largest volume corresponds to 1.62 ± 0.12 ml in the presence of cement leakage. The initial stiffness of the intact C2 vertebrae was taken as the reference value. The mean initial stiffness for non-porous cement (E = 3000 MPa) increased linearly (R2 = 0.98). The lowest stiffness (123.3 ± 5.8 N/mm) was measured in the intact C2 vertebrae. However, the highest stiffness (165.2 ± 5.2 N/mm) was measured when cement leakage out of the odontoid peg occurred. The mean initial stiffness of the base-only cemented group was 147.2 ± 8.4 N/mm compared with 157.9 ± 6.6 N/mm for the base and body cemented group. This difference was statistically significant (p < 0.0061). The mean initial stiffness for porous cement (E = 500 MPa) remains constant. Therefore, there is no difference between cemented and non-cemented junction. This difference was not statistically significant (p < 0.18). CONCLUSION: The present study showed that the low porous cement was able to significantly influence the stiffness of the augmented odontoid screw fixation in vitro, although further in vivo clinical studies should be undertaken. Our results suggest that only a small amount of non-porous cement is needed to restore stiffness at least to its pre-fracture level and this can be achieved with the injection of 0.7-1.2 ml of cement. These slides can be retrieved under Electronic Supplementary Material.

Biomechanical comparison of cemented versus non-cemented anterior screw fixation in type II odontoid fractures in the elderly: a cadaveric study.

BACKGROUND CONTEXT: Odontoid process fractures are the most common injuries of the cervical spine in the elderly. Anterior screw stabilization of type II odontoid process fractures improves survival and function in these patients but may be complicated by failure of fixation. PURPOSE: The present study aimed to determine whether cement augmentation of a standard anterior screw provides biomechanically superior fixation of type II odontoid fractures in comparison with a non-cemented standard screw. STUDY DESIGN: Twenty human cadaveric C2 vertebrae from elderly donors (mean age 83 years) were obtained. METHODS: Anderson and D'Alonzo type IIa odontoid fracture was created by transverse osteotomy, and fluoroscopy-guided anterior screw fixation was performed. The specimens were divided into two matched groups. The cemented group (n=10) had radiopaque high viscosity polymethylmethacrylate cement injected via Jamshidi needle into the base of the odontoid process. The other group was not augmented. A V-shaped punch was used for loading the odontoid in an anteroposterior direction until failure. The failure state was defined as screw cutout or 5% force decrease. Mean failure load and bending stiffness were calculated. RESULTS: The mean failure load for the cemented group was 352±12 N compared with 168±23 N for the non-cemented group (p<.001). The mean initial stiffness of the non-cemented group was 153±19 N/mm compared with 195±29 N/mm for the cemented group (p<.001) CONCLUSIONS: Cement augmentation of an anterior standard screw fixation of type II odontoid process fractures in elderly patients significantly increased load to failure under anteroposterior load in comparison with non-augmented fixation. This may be a valuable technique to reduce failure of fixation.