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OBJECTIVE There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence–lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5–S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Background Psoriatic arthritis (PsA) patient data from two phase 3 secukinumab trials (FUTURE 1, 5) were analysed to quantify the prevalence and extent of pre-existing radiographic damage (RD) at baseline; investigate the association of RD with swollen/tender joint counts (SJC/TJC) at baseline; and investigate the extent to which RD at baseline correlated with response to secukinumab. Methods Pooled data (N = 1554) provided baseline radiographic bone erosion and joint space narrowing (JSN) scores at pre-specified locations per the van der Heijde-modified total Sharp score (vdH-mTSS) for PsA and swollen and tender joint scores in the same joints at multiple visits. Overall patient RD and individual joints RD bone erosion and JSN scores were assessed. The association between joint activity (tenderness, swelling) and vdH-mTSS was assessed at the overall patient-level and individual joint tender, swollen scores (yes/no) and RD joint JSN and bone erosion scores at the individual joint-level. Treatment response was assessed using SJC/TJC at weeks 16 and 52 and the proportion of patients achieving minimal disease activity (MDA) over all assessments within 1 year from FUTURE 5 alone. Results A substantial prevalence of pre-existing RD with higher prevalence of erosion than JSN was observed (86% and 60% of patients had positive erosion and JSN scores, respectively); higher RD prevalence was associated with longer time since PsA diagnosis. Joint activity was weakly associated with RD at baseline at the patient-level (Pearson’s coefficients: range 0.12–0.18), but strongly associated at the individual joint-level, with a higher probability of tender/swollen joints to associate with higher JSN/erosion scores: all 42 analysed joints showed statistical significance at the 0.05 level (unadjusted) for the relationship between joint tenderness (yes/no) and its JSN score, all but one for tenderness and bone erosion scores, and all but 2 for swollen and JSN scores and for swollen and bone erosion score. Secukinumab (150/300 mg), reduced TJC and SJC across all values of baseline erosion and JSN scores at weeks 16 and 52. Patients with higher levels of RD were less likely to achieve zero tender/zero swollen joint status and had lower chance of achieving MDA. Conclusions PsA patients showed substantial prevalence of RD at baseline that correlated with time since diagnosis, but patient’s individual joint activity was strongly associated with pre-existing RD at those joints. Patients with the highest RD at baseline had a reduced likelihood of achieving zero joint count status.

STUDY DESIGN A laboratory study performed in a self-controlled fashion. OBJECTIVE The aim of this study was to examine whether "surgical smoke" generated by using the electrocautery on porcine spinal tissues could contain viable bacteria. SUMMARY OF BACKGROUND DATA The year 2020 has seen a surge in legislation regarding surgical smoke evacuation in the operating room across the United States. Surgical smoke contains numerous toxic and carcinogenic substances, which spine surgeons and operating room staff are regularly exposed to. Although the smoke's chemical toxicity has been extensively studied, little is known about its biohazard level. METHODS The electrocautery was used to "operate on" 20 segments of porcine spinal tissues on a clean bench. In each operation, the generated smoke was captured with a swab, which was positioned above the surgical site and within the smoke, to obtain bacteria cultures. Two other swabs-a tissue swab (swabbing the porcine tissue itself) and a blank swab (swabbing an empty sterile bowl)-were collected as controls. The culture results were compared among the three groups. An additional experiment was conducted to see whether using a mask can reduce the "infection rate" of the swab. RESULTS Although all blank swabs tested negative, 95% (19/20) of the smoke swabs tested positive, with a total of nine bacteria species identified. The most prevalent species observed in the smoke swabs included Serratia liquefaciens, Lactococcus garvieae, and Hafnia alvei, and so on. Among the positive smoke swabs, 84% (16/19) had one or more bacteria species that were consistent with the cultures of their corresponding tissue swabs. Using a surgical or N95 mask reduced the "infection rate" of the swab. CONCLUSION "Surgical smoke" generated by electrocauterization of porcine spinal tissues contains viable bacteria. Further research in actual spine surgery is needed next.Level of Evidence: N/A.