Maturation of mammalian H/ACA box snoRNAs: PAPD5-dependent adenylation and PARN-dependent trimming

Small nucleolar and small Cajal body RNAs (snoRNAs and scaRNAs) of the H/ACA box and C/D box type are generated by exonucleolytic shortening of longer precursors. Removal of the last few nucleotides at the 3' end is known to be a distinct step. We report that, in human cells, knock-down of the poly(A) specific ribonuclease (PARN), previously implicated only in mRNA metabolism, causes the accumulation of oligoadenylated processing intermediates of H/ACA box but not C/D box RNAs. In agreement with a role of PARN in snoRNA and scaRNA processing, the enzyme is concentrated in nucleoli and Cajal bodies. Oligo(A) tails are attached to a short stub of intron sequence remaining beyond the mature 3' end of the snoRNAs. The noncanonical poly(A) polymerase PAPD5 is responsible for addition of the oligo(A) tails. We suggest that deadenylation is coupled to clean 3' end trimming, which might serve to enhance snoRNA stability

Navigation system for robot-assisted intra-articular lower-limb fracture surgery

Purpose In the surgical treatment for lower-leg intra-articular fractures, the fragments have to be positioned and aligned to reconstruct the fractured bone as precisely as possible, to allow the joint to function correctly again. Standard procedures use 2D radiographs to estimate the desired reduction position of bone fragments. However, optimal correction in a 3D space requires 3D imaging. This paper introduces a new navigation system that uses pre-operative planning based on 3D CT data and intra-operative 3D guidance to virtually reduce lower-limb intra-articular fractures. Physical reduction in the fractures is then performed by our robotic system based on the virtual reduction. Methods 3D models of bone fragments are segmented from CT scan. Fragments are pre-operatively visualized on the screen and virtually manipulated by the surgeon through a dedicated GUI to achieve the virtual reduction in the fracture. Intra-operatively, the actual position of the bone fragments is provided by an optical tracker enabling real-time 3D guidance. The motion commands for the robot connected to the bone fragment are generated, and the fracture physically reduced based on the surgeon’s virtual reduction. To test the system, four femur models were fractured to obtain four different distal femur fracture types. Each one of them was subsequently reduced 20 times by a surgeon using our system. Results The navigation system allowed an orthopaedic surgeon to virtually reduce the fracture with a maximum residual positioning error of 0.95±0.3mm (translational) and 1.4∘±0.5∘ (rotational). Correspondent physical reductions resulted in an accuracy of 1.03 ± 0.2 mm and 1.56∘±0.1∘, when the robot reduced the fracture. Conclusions Experimental outcome demonstrates the accuracy and effectiveness of the proposed navigation system, presenting a fracture reduction accuracy of about 1 mm and 1.5∘, and meeting the clinical requirements for distal femur fracture reduction procedures

Vision-based real-time position control of a semi-automated system for robot-assisted joint fracture surgery

Purpose: Joint fracture surgery quality can be improved by robotic system with high-accuracy and high-repeatability fracture fragment manipulation. A new real-time vision-based system for fragment manipulation during robot-assisted fracture surgery was developed and tested. Methods: The control strategy was accomplished by merging fast open-loop control with vision-based control. This two-phase process is designed to eliminate the open-loop positioning errors by closing the control loop using visual feedback provided by an optical tracking system. Evaluation of the control system accuracy was performed using robot positioning trials, and fracture reduction accuracy was tested in trials on ex vivo porcine model.Results: The system resulted in high fracture reduction reliability with a reduction accuracy of 0.09mm (translations) and of (Formula presented.) (rotations), maximum observed errors in the order of 0.12mm (translations) and of (Formula presented.) (rotations), and a reduction repeatability of 0.02mm and (Formula presented.). Conclusions: The proposed vision-based system was shown to be effective and suitable for real joint fracture surgical procedures, contributing a potential improvement of their quality

Isolated talonavicular arthrodesis in patients with rheumatoid arthritis of the foot and tibialis posterior tendon dysfunction

<p>Abstract</p> <p>Background</p> <p>The foot is often affected in patients with rheumatoid arthritis. Subtalar joints are involved more frequently than ankle joints. Deformities of subtalar joints often lead to painful flatfoot and valgus deformity of the heel. Major contributors to the early development of foot deformities include talonavicular joint destruction and tibialis posterior tendon dysfunction, mainly due to its rupture.</p> <p>Methods</p> <p>Between 2002 and 2005 we performed isolated talonavicular arthrodesis in 26 patients; twenty women and six men. Tibialis posterior tendon dysfunction was diagnosed preoperatively by physical examination and by MRI. Talonavicular fusion was achieved via screws in eight patients, memory staples in twelve patients and a combination of screws and memory staples in six cases. The average duration of immobilization after the surgery was four weeks, followed by rehabilitation. Full weight bearing was allowed two to three months after surgery.</p> <p>Results</p> <p>The mean age of the group at the time of the surgery was 43.6 years. MRI examination revealed a torn tendon in nine cases with no significant destruction of the talonavicular joint seen on X-rays. Mean of postoperative followup was 4.5 years (3 to 7 years). The mean of AOFAS Hindfoot score improved from 48.2 preoperatively to 88.6 points at the last postoperative followup. Eighteen patients had excellent results (none, mild occasional pain), six patients had moderate pain of the foot and two patients had severe pain in evaluation with the score. Complications included superficial wound infections in two patients and a nonunion developed in one case.</p> <p>Conclusions</p> <p>Early isolated talonavicular arthrodesis provides excellent pain relief and prevents further progression of the foot deformities in patients with rheumatoid arthritis and tibialis posterior tendon dysfunction.</p

Image-Guided Surgical Robotic System for Percutaneous Reduction of Joint Fractures

Complex joint fractures often require an open surgical procedure, which is associated with extensive soft tissue damages and longer hospitalization and rehabilitation time. Percutaneous techniques can potentially mitigate these risks but their application to joint fractures is limited by the current sub-optimal 2D intra-operative imaging (fluoroscopy) and by the high forces involved in the fragment manipulation (due to the presence of soft tissue, e.g., muscles) which might result in fracture malreduction. Integration of robotic assistance and 3D image guidance can potentially overcome these issues. The authors propose an image-guided surgical robotic system for the percutaneous treatment of knee joint fractures, i.e., the robot-assisted fracture surgery (RAFS) system. It allows simultaneous manipulation of two bone fragments, safer robot-bone fixation system, and a traction performing robotic manipulator. This system has led to a novel clinical workflow and has been tested both in laboratory and in clinically relevant cadaveric trials. The RAFS system was tested on 9 cadaver specimens and was able to reduce 7 out of 9 distal femur fractures (T- and Y-shape 33-C1) with acceptable accuracy (≈1 mm, ≈5°), demonstrating its applicability to fix knee joint fractures. This study paved the way to develop novel technologies for percutaneous treatment of complex fractures including hip, ankle, and shoulder, thus representing a step toward minimally-invasive fracture surgeries

Radiographic evaluation of calcaneal fractures: To measure or not to measure

Objective: The aim of this study was to correlate the functional outcome after treatment for displaced intra-articular calcaneal fracture with plain radiography. Design: The design was a prognostic study of a retrospective cohort with concurrent follow-up. Patients: A total of 33 patients with a unilateral calcaneal fracture and a minimum follow-up of 13 months participated. Patients filled in three disease-specific questionnaires, graded their satisfaction and the indication for an arthrodesis was noted. Standardised radiographs were made of the previously injured side and the normal (control) side. Different angles and distances were measured on these radiographs and compared with values described in the literature. The differences in values in angles and distances between the injured and uninjured (control) foot were correlated with the outcome of the questionnaires, and the indication for an arthrodesis. Results: None of the angles correlated with the disease-specific outcome scores. Of the angles only the tibiotalar angle correlated with the VAS (r=0.35, p=0.045) and only the absolute foot height correlated with the indication for an arthrodesis (odds=0.70, CI=0.50-0.99). Conclusion: In this study the radiographic evaluation correlated poorly with the final outcome. Measurements on plain radiographs seem not to be useful in determining outcome after intra-articular calcaneal fractures

Living within the safe and just Earth system boundaries for blue water

Safe and just Earth system boundaries (ESBs) for surface water and groundwater (blue water) have been defined for sustainable water management in the Anthropocene. Here we assessed whether minimum human needs could be met with surface water from within individual river basins alone and, where this is not possible, quantified how much groundwater would be required. Approximately 2.6 billion people live in river basins where groundwater is needed because they are already outside the surface water ESB or have insufficient surface water to meet human needs and the ESB. Approximately 1.4 billion people live in river basins where demand-side transformations would be required as they either exceed the surface water ESB or face a decline in groundwater recharge and cannot meet minimum needs within the ESB. A further 1.5 billion people live in river basins outside the ESB, with insufficient surface water to meet minimum needs, requiring both supply- and demand-side transformations. These results highlight the challenges and opportunities of meeting even basic human access needs to water and protecting aquatic ecosystems