ABSTRACT
AIMS: With resumption of elective spine surgery services in the UK following the first wave of the COVID-19 pandemic, we conducted a multicentre British Association of Spine Surgeons (BASS) collaborative study to examine the complications and deaths due to COVID-19 at the recovery phase of the pandemic. The aim was to analyze the safety of elective spinal surgery during the pandemic. METHODS: A prospective observational study was conducted from eight spinal centres for the first month of operating following restoration of elective spine surgery in each individual unit. Primary outcome measure was the 30-day postoperative COVID-19 infection rate. Secondary outcomes analyzed were the 30-day mortality rate, surgical adverse events, medical complications, and length of inpatient stay. RESULTS: In all, 257 patients (128 males) with a median age of 54 years (2 to 88) formed the study cohort. The mean number of procedures performed from each unit was 32 (16 to 101), with 118 procedures (46%) done as category three prioritization level. The majority of patients (87%) were low-medium "risk stratification" category and the mean length of hospital stay was 5.2 days. None of the patients were diagnosed with COVID-19 infection, nor was there any mortality related to COVID-19 during the 30-day follow-up period, with 25 patients (10%) having been tested for symptoms. Overall, 32 patients (12%) developed a total of 34 complications, with the majority (19/34) being grade 1 to 2 Clavien-Dindo classification of surgical complications. No patient required postoperative care in an intensive care setting for any unexpected complication. CONCLUSION: This study shows that safe and effective planned spinal surgical services can be restored avoiding viral transmission, with diligent adherence to national guidelines and COVID-19-secure pathways tailored according to the resources of the individual spinal units. Cite this article: Bone Jt Open 2021;2(12):1096-1101.
ABSTRACT
AIMS: This pilot study tested the performance of a rapid assay for diagnosing prosthetic joint infection (PJI), which measures synovial fluid calprotectin from total hip and knee revision patients. METHODS: A convenience series of 69 synovial fluid samples from revision patients at the Norfolk and Norwich University Hospital were collected intraoperatively (52 hips, 17 knees) and frozen. Synovial fluid calprotectin was measured retrospectively using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone AS) and compared to International Consensus Meeting (ICM) 2018 criteria and clinical case review (ICM-CR) gold standards. RESULTS: According to ICM, 24 patients were defined as PJI positive and the remaining 45 were negative. The overall accuracy of the lateral flow test compared to ICM was 75.36% (52/69, 95% CI 63.51% to 84.95%), sensitivity and specificity were 75.00% (18/24, 95% CI 53.29% to 90.23%) and 75.56% (34/45, 95% CI 60.46% to 87.12%), respectively, positive predictive value (PPV) was 62.07% (18/29, 95% CI 48.23% to 74.19%) and negative predictive value (NPV) was 85.00% (34/40, 95% CI 73.54% to 92.04%), and area under the receiver operating characteristic (ROC) curve (AUC) was 0.78 (95% CI 0.66 to 0.87). Patient data from discordant cases were reviewed by the clinical team to develop the ICM-CR gold standard. The lateral flow test performance improved significantly when compared to ICM-CR, with accuracy increasing to 82.61% (57/69, 95% CI 71.59% to 90.68%), sensitivity increasing to 94.74% (18/19, 95% CI 73.97% to 99.87%), NPV increasing to 97.50% (39/40, 95% CI 85.20% to 99.62%), and AUC increasing to 0.91 (95% CI 0.81 to 0.96). Test performance was better in knees (100.00% accurate (17/17, 95% CI 80.49% to 100.00%)) compared to hips (76.92% accurate (40/52, 95% CI 63.16% to 87.47%)). CONCLUSION: This study demonstrates that the calprotectin lateral flow assay could be an effective diagnostic test for PJI, however additional prospective studies testing fresh samples are required.Cite this article: Bone Joint Res. 2020;9(5):202-210.
ABSTRACT
This paper describes the adaptation of the laser-induced fluorescence measurement technique for the investigation of the primary breakup of modern diesel and gasoline direct injection sprays. To investigate the primary breakup, a microscopic technique is required, and with the help of special tracer dyes, a high fluorescence signal can be achieved in the visible range of the electromagnetic spectrum, resulting in good image quality with a nonintensified camera. Besides the optimization of the optical setup for the microscopic field of view, different tracer dyes are compared, and their solubility and fluorescence are tested in the desired surrogate and real-world fuels. As a tracer, the phenoxazine dye Nile Red was found to provide sufficient solubility in alkanes as well as suitable emission and excitation spectrum for the use of the second-harmonic frequency of a Nd:YAG laser (532 nm). The good quantum efficiency delivered by Nile Red also meant that single-shot images clearly showing spray structures in regions measuring up to 3 mm by 3 mm around the nozzle outlet could be recorded. Compared to relatively easy shadowgraph techniques and complex and costly x-ray synchrotron measurements, light sheet fluorescence microscopic imaging is not overly complex yet delivers excellent data on spray structures as well as qualitative fuel distribution.
ABSTRACT
With an increasingly aging population, adult spinal deformity is becoming more common. This can be associated with increased morbidity. Results from multicentre studies of deformity surgery correction confirm complication rates as high as 40 percent. Most often a bad result is associated with inadequate restoration of the sagittal balance. Posterior vertebral body resection has been described as a method to correct significant deformity, but this is a complicated procedure. It is possible to do this in the thoracic spine where nerve roots can be sacrificed, but it is difficult in the lumbar spine due to the significant role of the lumbar nerve roots. We describe a safer technique for correction of deformity using a three stage process. This appears to be a good technique for revision surgery.
