Prolonged electrical stimulation causes no damage to sacral nerve roots in rabbits

Previous studies have shown that, anode block electrical stimulation of the sacral nerve root can produce physiological urination and reconstruct urinary bladder function in rabbits. However, whether long-term anode block electrical stimulation causes damage to the sacral nerve root remains unclear, and needs further investigation. In this study, a complete spinal cord injury model was established in New Zealand white rabbits through T9–10 segment transection. Rabbits were given continuous electrical stimulation for a short period and then chronic stimulation for a longer period. Results showed that compared with normal rabbits, the structure of nerve cells in the anterior sacral nerve roots was unchanged in spinal cord injury rabbits after electrical stimulation. There was no significant difference in the expression of apoptosis-related proteins such as Bax, Caspase-3, and Bcl-2. Experimental findings indicate that neurons in the rabbit sacral nerve roots tolerate electrical stimulation, even after long-term anode block electrical stimulation.     

A systematic review of CAD/CAM fit restoration evaluations

The evolution and development of CAD/CAM systems have led to the production of prosthetic reconstructions by going beyond the use of traditional techniques. Precision adjustment of prosthetic elements is considered essential to ensure sustainable restoration and dental preparation. The purpose of this article was to summarise the current literature on the fitting quality of fixed prostheses obtained by CAD/CAM technology.     

Left ventricular pseudoaneurysm after mitral valve replacement

Development of left ventricular pseudoaneurysm is a rare complication of mitral valve surgery and requires urgent surgical intervention. We describe a case of pseudoaneurysm of membranous septum following repeat mitral valve replacement with the use of multimodality imaging.     

Evaluation of a Neural Network-Based Control Strategy for a Cost-Effective Externally-Powered Prosthesis

ABSTRACT

This paper presents a control strategy that compensates for the nonlinearity in the inexpensive sensors and hardware of a cost effective prosthetic hand. The control strategy uses neural network-based force control and sensory feedback to detect disturbance induced by slippage. The neural network approach is chosen over other nonlinear models because it is easy to implement and it offered the additional advantage of having its parameters easily adjusted over the life span of the device. The proposed strategy was evaluated on a functional multi-digit underactuated prosthetic hand. The initial and incremental forces exerted from each finger were adjusted to balance the amount of disturbance and the deformation of the objects. Experiments were conducted to test the performance of the protocol in situations encountered in activities of daily living. The displacement of each object under three grasping configurations was measured as a performance criterion while the object's mass was changed. The results showed that with the adjusted parameters for each grasping configuration, the control strategy was able to detect the dynamic changes in mass of the object and was also able to successfully adjust the grasping force before the object drops from the hand.     

Acetabular Protrusion Following Endoprosthetic hip Surgery: A Multifactorial Study

Acetabular protrusion was found in 56 out of 211 patients fitted with a hemiprosthesis. the indication for operation was acute femoral neck fracture or failure following a previous internal fixation. A number of radiological variables were analysed with respect to their possible association with preoperative, operative and follow-up variables. After a preliminary screening of variables a deeper analysis was performed by fitting log-linear models to the data. Our analysis showed that the development of protrusion has a significant association with follow-up time. A previous hip operation was also significantly associated with the development of protrusion. This may be an indication for total hip replacement in some patients who now receive a hemiprosthesis as a secondary operation. Acetabular protrusion was significantly associated with the development of postoperative pain, while the other clinical symptoms and signs lacked any direct association with protrusion. Although acetabular protrusion and loosening of the prosthetic stem showed a significant association the analysis indicated that pain was primarily due to protrusion.     

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Preclotting is an essential procedure for porous fabric vascular prostheses, but fatal bleeding due to fibrinolysis after implantation can occur in some cases. To overcome this problem, a method was developed to seal highly porous fabric vascular prostheses with adipose connective tissue fragments. A piece of subcutaneous adipose connective tissue weighing approximately 1 g was minced with scissors and stirred into 20 mL of saline, thereby creating a tissue suspension. This was sieved through the wall of a highly porous fabric prosthesis from the outside to the inside by intraluminal suction. The prostheses were implanted in the thoracic descending aortae of 20 dogs and removed from 1 h to 1 year after implantation. Twelve preclotted prostheses were used as controls. None of the treated grafts experienced bleeding complications postoperatively. In the controls, the chest wall was closed after the bleeding stopped from the suture line and through the prosthesis wall, but problems occurred after surgery. Three out of 12 control animals (25%) bled in the pleural cavity within 24 h. In the tissue-sealed grafts, smooth neointima formation without any degenerative changes was observed during a 1-year observation period.     

A comparison of function after limb salvage with non-invasive expandable or modular prostheses in children

BackgroundModular and non-invasive expandable prostheses have been developed to provide a functional knee joint that allows future expansion as growth occurs in the contralateral extremity in children with bone sarcomas that require removal of the growth plate. This study aimed to evaluate the functional outcomes of paediatric patients who received either a non-invasive expandable or modular prosthesis for bone sarcomas arising around the knee.MethodsWe evaluated clinician-reported, patient-reported and measured function in 42 paediatric patients at least one year (median age at assessment 19.1 years) after limb salvage surgery, and compared patients who received modular system prostheses (N = 29, median age 15.5), who did not require lengthening procedures to those who received non-invasive expandable prostheses (N = 13, median age 11.1) requiring lengthening procedures (median 5).ResultsThe number of revisions and time to first revision did not differ between the two groups. There were no differences between the two groups in total scores on the Enneking Musculoskeletal Tumor Society Scale, the Toronto Extremity Salvage Scale, and the Functional Mobility Assessment. Children with non-invasive expandable prostheses climbed stairs (11.93 ± 4.83 versus 16.73 ± 7.24 s, p = 0.02) in less time than those with modular prostheses.ConclusionOur results suggest that the non-invasive expandable prosthesis produces similar functional results to the more traditional modular prosthesis.     

Image-guided periacetabular osteotomy: computer-assisted navigation compared with the conventional technique: A randomized study of 36 patients followed for 2 years

Background?Periacetabular osteotomy (PAO) is an effective but technically demanding surgical procedure. We evaluated the efficiency of computer-assisted navigation in PAO and compared it with the traditional approach.

Patients and methods?We performed a randomized study of 36 patients undergoing PAO using either the CT-based, computer-assisted navigation technique or the conventional approach. The operative details, radiographic results, and functional outcomes were compared between groups.

Results?Patients in the conventional surgery group required an average of 4.4 (2–7) images of intraoperative radiographs, whereas only 0.6 (0–1) images were required in the navigation group. The operation time was 21 min shorter with computer-assisted navigation. No significant difference with regard to operative blood loss, transfusion requirement, correction of deformity, and functional improvement was found. Complications such as intraarticular damage, osteonecrosis, or neurovascular injury were not encountered.

Interpretation?A computer-assisted navigation system is a feasible tool to provide real-time image guidance and facilitate PAO. However, it offers little additional benefit when the surgery is done by an experienced surgeon.