Abstract. Background. Cauda equina syndrome (CES) is a rare serious condition that, if missed at initial presentation, can lead to serious disability. Early diagnosis is crucial for a favourable outcome. Few studies included urodynamic test and measurement of post-void residual urine (PVR) as an adjunct screening tool for acute CES before proceeding to MRI scan, yet there are differences in the cut-off point as a threshold volume to be considered as a red flag for doing MRI amongst these studies. Aim. Meta-analysis and systematic review of literature that included PVR as a predictive tool in CES to identify the reliability of PVR and the optimal numerical value to be considered as red flag. Material & Methods. A comprehensive literature search was undertaken in PubMed, Medline, and Embase databases using our search strategy. Meta-analysis of collated data. Results. A total of seven studies were included with a total of 938 patients. The number of cases suitable for meta-analysis was 714. CES was confirmed in 73. urodynamic testing and PVR diagnosed 86 and excluded 426. The sensitivity of PVR>100ml was 64% (CI 97.5%: 0.44–0.80), specificity 59.2% (CI 97.5%: 0.46 – 0.711), while PVR >200 showed more predictive figures, with sensitivity improved to 83.1% (CI 97.5%: 0.62–0.94) and specificity to 93.5% (CI 97.5%: 0.50–0.99). Conclusions. Urodynamics test is an essential tool in CES assessment. Authors recommend PVR > 200 ml as the numerical cut-off point to be considered as a red flag that if present with other clinical red flags, urgent MRI is recommended in suspected CES

Introduction. Pixel Value Ratio (PVR) is a radiographic measure of the relative density of the regenerate to the adjacent bone. This has been reported as an objective criterion for regenerate healing and a guide for when to allow full weight bearing (FWB) in lengthening with intramedullary telescopic nails. The threshold for which magnitude of PVR is adequate to allow bearing full weight is not yet agreed. The aim of this study was to identify from our cohort of adult limb lengthening patients the time to FWB following lengthening, the PVR at this point, and how this compared with the recommended values in the literature. Materials and Methods. A retrospective database review identified 30 adult patients treated with the PRECICE femoral nail by two senior authors. Time from completion of lengthening to instruction to fully weight bear was noted. The PVR was calculated for each cortex on plain radiographs taken at each postoperative visit following completion of lengthening. Significance was set at p <0.05. Results. The median age was 30.5 years (IQR 22.5 – 42.5), 19 male and 11 female patients were included. The underlying cause of shortening was post traumatic in 12 (40%) with the remaining due to a wide variety of causes including congenital, infective, and idiopathic leg length discrepancies. Twenty-two nails were antegrade and the mean distance lengthened was 42 mm. Median time from completion of lengthening to full weight bearing was 42 days (IQR 28 – 69). The overall mean PVR at FWB was 0.79. Each surgeon had differing protocols for weightbearing, however there was no statistical difference between time to weight bearing, nor the mean PVR at FWB. There were no implant failures, shortening, or regenerate fractures. Conclusions. We report on our cohort of adult patients treated with intramedullary lengthening nails with a mean PVR of 0.79 at time of full weightbearing. This is considerably lower than the values reported in the literature ranging from 0.90 to 0.93. We therefore suggest that weightbearing following lengthening nails can be permitted earlier than previously reported without an increased risk of complication

Lengthening of the humerus is now an established technique. We compared the complications of humeral lengthening with those of femoral lengthening and investigated whether or not the callus formation in the humerus proceeds at a higher rate than that in the femur. A total of 24 humeral and 24 femoral lengthenings were performed on 12 patients with achondroplasia. We measured the pixel value ratio (PVR) of the lengthened area on radiographs and each radiograph was analysed for the shape, type and density of the callus. The quality of life (QOL) of the patients after humeral lengthening was compared with that prior to surgery. The complication rate per segment of humerus and femur was 0.87% and 1.37%, respectively. In the humerus the PVR was significantly higher than that of the femur. Lower limbs were associated with an increased incidence of concave, lateral and central callus shapes. Humeral lengthening had a lower complication rate than lower-limb lengthening, and QOL increased significantly after humeral lengthening. Callus formation in the humerus during the distraction period proceeded at a significantly higher rate than that in the femur. . These findings indicate that humeral lengthening has an important role in the management of patients with achondroplasia

Purpose. There are concerns with regard to the physiological effects of reamed intramedullary femoral fracture stabilisation in patients who have received a pulmonary injury. This large animal study used invasive monitoring techniques to obtain sensitive cardiopulmonary measurements and compared the responses to Early Total Care (reamed intramedullary femoral fracture fixation) to Damage Control Orthopaedics (external fixation), after the induction of acute lung injury. We hypothesised a greater cardiopulmonary response to intramedullary fracture fixation. Method. Acute lung injury (PaO2/FiO2 < 200 mmHg) was induced in 12 invasively monitored and terminally anaesthetised male sheep via the infusion of oleic acid into the right atrium. Each animal underwent surgical femoral osteotomy and fixation with either reamed intramedullary (n=6) or external fixation (n=6). Simultaneous haemodynamic and arterial blood-gas measurements were recorded at baseline and at 5, 30 and 60 minutes after fracture stabilisation. Results. The mean (S.E.) PaO2/FiO2 fell significantly (p<0.05) from 359(37) to 107 (23) and 382 (33) to 128 (18) in the externally fixated and intramedullary nailed groups respectively as a result of the acute lung injury. The further combined effect of surgical osteotomy and subsequent fracture fixation produced a mean (+/− S.E.) PaO2/FiO2 of 114 (21) and 113 (12), in the externally fixated and intramedullary nailed groups respectively, immediately after surgery. This was not significantly different either within or between groups. Similarly the pulmonary vascular resistance (PVR) measured at 4.7 (0.9) and 4.2 (0.5) in the externally fixated and intramedullary nailed groups respectively after lung injury changed to 4.9 (0.7) and 4.3 (0.6) after surgical osteotomy and subsequent fracture fixation which, again was not significantly different either within or between groups. No significant difference in either PaO2/FiO2 or PVR was detected at the monitored 5, 30 and 60 minute intervals that followed fracture stabilisation. Conclusion. Against a background of standardised acute lung injury, there appeared to be no further deterioration produced by the method of isolated femoral fracture fixation in two sensitive physiological parameters commonly used by intensive care physicians