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Artificial atlanto-odontoid joint replacement through a transoral approach.

ABSTRACT: Resection of the odontoid process and anterior arch of the atlas results in atlantoaxial instability, which if left uncorrected may lead to severe neurological complications. Currently, such atlantoaxial instability is corrected by anterior and/or posterior C1-C2 fusion. However, this results in considerable loss of rotation function of the atlantoaxial complex. From the viewpoint of retaining the rotation function and providing stability, we designed an artificial atlanto-odontoid joint based on anatomical measurements of 50 pairs of dry atlantoaxial specimens by digital calipers and 10 fresh cadaveric specimens by microsurgical techniques. The metal-on-metal titanium alloy joint has an arc-shaped atlas component, and a hollow cylindrical bushing into which fits a rotation axle of an inverted v-shaped axis component and is implanted through a transoral approach. After the joint was implanted onto specimens with anterior decompression, biomechanical tests were performed to compare the stability parameters in the intact state, after decompression, after artificial joint replacement, and after fatigue test. Compared to the intact state, artificial joint replacement resulted in a significant decrease in the range of motion (ROM) and neutral zone (NZ) during flexion, extension, and lateral bending (P < 0.001); however, with regard to axial rotation, there was no significant difference in ROM (P = 0.405), a significant increase in NZ (P = 0.008), and a significant decrease in stiffness (P = 0.003). Compared to the decompressed state, artificial joint replacement resulted in a significantly decreased ROM (P B 0.021) and NZ (P B 0.002) and a significantly increased stiffness (P \ 0.001) in all directions. Following artificial joint replacement, there was no significant difference in ROM (P C 0.719), NZ (P C 0.580), and stiffness (P C 0.602) in all directions before and after the fatigue test. The artificial joint showed no signs of wear and tear after the fatigue test. This artificial atlanto-odontoid joint may be useful in cases of odontoid resection due to malunion or nonunion of odontoid fracture, atraumatic odontoid fracture, irreducible atlas dislocation, posterior atlantoaxial subluxation, or congenital skull base abnormalities.

SUBMITTER: Lu B

PROVIDER: S-EPMC2615126 | biostudies-other | 2009 Jan

REPOSITORIES: biostudies-other

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Project description:The present study was designed to investigate the correlation between glutathione S-transferase M1 (GSTM1) gene polymorphism and the recovery of patients undergoing artificial hip replacement. A total of 241 patients including 149 males (61.8%) and 92 females (38.9%) who received artificial hip replacement in People's Hospital of Rizhao between December 2010 and October 2016 were enrolled to serve as the observation group. Patients were divided into two subgroups according to the loss of GSTM1. A total of 80 healthy subjects who udenrwent a physical examination in our hospital at the same period were selected to serve as the control group. The control group included 41 males (51.25%) and 39 females (48.75%). GSTM1 gene genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). All patients were followed up for 12 months. Clinical data were compared between the deletion and non-deletion groups and the hospitalization time and the length of the use of antibiotics were compared. Deletion rate of GSTM1 gene in the observation group was 67.63%, which was significantly different from that in the healthy control group [odds ratio (OR)=1.51, 95% confidence interval (CI): 1.075-2.023, P<0.05]. Notably, a significant difference was indicated in the recovery between patients with and without GSTM1 gene deletion after a year discharged from hospital (P<0.05). There was no significant difference according to sex, age, hypertension, smoking history, leukocyte, hemoglobin, platelet and BMI index between patients in deletion and non-deletion groups (P>0.05). However, there was a significant difference in the number of patients with diabetes between the two groups (P<0.05). Hospitalization time and the length of antibiotics use were significantly longer in deletion group compared with non-deletion group (P<0.05). Infection rate in the deletion group was significantly higher than that in the non-deletion group. Results suggested that GSTM1 gene polymorphism may be correlated with recovery of patients undergoing artificial hip replacement, and GSTM1 gene deletion may correlated with poor recovery.

Project description:The volume of joint replacement surgery has risen steadily in recent years, because the population is aging and increasingly wishes to reserve a high functional status onward into old age. Infection is among the more common complications of joint replacement surgery, arising in 0.2% to 2% of patients, or as many as 9% in special situations such as the implantation of megaprostheses. The associated morbidity and mortality are high. It is thus very important to minimize risk factors for infection and to optimize the relevant diagnostic and therapeutic strategies.This review is based on pertinent publications retrieved by a selective search in PubMed, including current guidelines and expert recommendations.The crucial diagnostic step is joint biopsy for the identification of the pathogenic organism, which succeeds with over 90% sensitivity and specificity. If the prosthesis is firmly anchored in bone, the pathogen is of a type that responds well to treatment, and symptomatic infection has been present only for a short time, then rapidly initiated treatment can save the prosthesis in 35-90% of cases. The pillars of treatment are thorough surgical care (radical débridement) and targeted antibiotic therapy. On the other hand, if the prosthesis is loose or the pathogen is of a poorly treatable type, the infection can generally only be cured by a change of the prosthesis. This can be performed in either one or two procedures, always in conjunction with systemic antibiotic therapy tailored to the specific sensitivity and resistance pattern of the pathogen.The risk of infection of an artificial joint is low, but the overall prevalence of such infections is significant, as the number of implanted joints is steadily rising. Artificial joint infections should be treated by a standardized algorithm oriented toward the recommendations of current guidelines. Many of these recommendations, however, are based only on expert opinion, as informative studies providing high-grade evidence are lacking. Thus, for any particular clinical situation, there may now be multiple therapeutic approaches with apparently comparable efficacy. Randomized trials are urgently needed.

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Artificial atlanto-odontoid joint replacement through a transoral approach.

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