Age and distraction are determinants of performance on a novel visual search task in aged Beagle dogs

Aging has been shown to disrupt performance on tasks that require intact visual search and discrimination abilities in human studies. The goal of the present study was to determine if canines show age-related decline in their ability to perform a novel simultaneous visual search task. Three groups of canines were included: a young group (N = 10; 3 to 4.5 years), an old group (N = 10; 8 to 9.5 years), and a senior group (N = 8; 11 to 15.3 years). Subjects were first tested for their ability to learn a simple two-choice discrimination task, followed by the visual search task. Attentional demands in the task were manipulated by varying the number of distracter items; dogs received an equal number of trials with either zero, one, two, or three distracters. Performance on the two-choice discrimination task varied with age, with senior canines making significantly more errors than the young. Performance accuracy on the visual search task also varied with age; senior animals were significantly impaired compared to both the young and old, and old canines were intermediate in performance between young and senior. Accuracy decreased significantly with added distracters in all age groups. These results suggest that aging impairs the ability of canines to discriminate between task-relevant and -irrelevant stimuli. This is likely to be derived from impairments in cognitive domains such as visual memory and learning and selective attention.     

The animal experiment of a new optimised distraction implant

Our aim was to evaluate the function of a new optimised distraction implant. Six dogs with alveolar bone defects had a total of 18 distraction, and 6 normal, implants inserted into edentulous mandibular ridges after osteotomy. Five days after insertion the distraction implants were activated at a rate of 1 mm/2 days to achieve a distraction height of 6 mm. Radiographs were taken at 0, 1, 2, and 3 months after distraction. Two dogs were killed after 1, 2, and 3 months, respectively, and 12 distraction implants taken from the different time points were evaluated by microcomputed tomographic (MicroCT) scanning and histological examination. The other 6 distraction, and the 6 normal, implants were compared after osseointegration with a fatigue test. The results showed that all the distraction implants had successfully distracted the bone to the anticipated height. Radiographs showed that the density of the regenerated bone increased steadily during the consolidation period. MicroCT showed that the regenerated bone was comparable with the native bone 3 months after distraction. Both native and regenerated bone had osseointegrated histologically by 1 month and 3 months after distraction. The experiment successfully confirmed the usefulness and feasibility of this new distraction implant, and suggests interesting clinical uses.     

Correction of a Deformed Thumb by Distraction of the Phalanx

We used distraction osteogenesis to correct six deformed thumbs in four patients ranging in age from 4 to 7 years. Two of the patients had Apert syndrome (syndromic craniosynostosis with symmetrical syndactyly) and two had polydactyly. We used a small fixator with a ball joint and successfully corrected the angular deformity after lengthening the proximal phalanx by distraction. This single inclusive procedure was extremely useful. We found the optimal distraction regimen for the digital phalanx was a one day waiting period and lengthening at 1 mm/day. The mean healing indexes were 37.2 days/cm (range 24.2 to 41.5) in those with Apert syndrome and 64.3 days/cm in those with polydactyly (62.5 and 66.0). Our results suggest that osteogenesis at the distraction site may be quicker in patients with Apert syndrome than in those with polydactyly.     

Auriculo-condylar syndrome: Diagnosis,treatment, and family history of a patient

The auriculo-condylar syndrome is caused by abnormalities of the first and second pharyngeal arches during embryonic development. Its inheritance follows the autosomal dominant pattern. Both familial and individual cases are reported in the literature. The syndrome is characterized by wide phenotypic variation, with affected individuals expressing clinical signs of variable severity due to variable expressivity of the responsible genes. Clinical signs of the syndrome include auricular malformation, hypoplasia of the mandibular condyles, anomalies of the temporomandibular joints, malocclusion, and, in more severe cases, cleft palate, glossoptosis, facial asymmetry, and respiratory problems. The aim of this article is to report a case of a female patient with signs of the auriculo-condylar syndrome and to present the pedigree of her family. Clinical findings, diagnosis, treatment plan, and final treatment are analyzed.     

Long-term skeletal stability after maxillary advancement with distraction osteogenesis in cleft lip and palate patients: A systematic review

Objective:To systematically review the long-term skeletal stability after maxillary advancement with distraction osteogenesis (DO) in cleft lip and palate (CLP) patients.Materials and Methods:Electronic databases, grey literature, and reference list searches were conducted. The inclusion criteria were stability of maxillary advancement with distraction osteogenesis assessed at the posttreatment follow-up ≥ 1 year in CLP patients. Full articles were retrieved from abstracts or titles that appear to meet the inclusion criteria or lacked sufficient detail for immediate exclusion. Once full articles were collected, they were again reviewed considering more detailed inclusion criteria for a final selection decision. A methodologic quality assessment tool was utilized.Results:Thirty abstracts/titles met the initial search criteria, and 13 articles were finally selected. Overall, methodologic quality scores were high in only one randomized clinical trial. After maxillary advancement with DO in CLP patients, the long-term horizontal relapse in A-point was less than 15% in eight studies and between 20% and 25% in four studies. The study that was judged as a high-quality study reported 8.2% horizontal relapse in A-point. The relapse rate was higher in DO with external distracter device than DO with internal distracter device.Conclusions:Current evidence suggests maxillary advancement with DO has good stability in CLP patients with moderate and severe maxillary hypoplasia.     

The role of the lateral pterygoid muscle in the sagittal fracture of mandibular condyle (SFMC) healing process

The aim of this study was to examine the role of the lateral peterygoid muscle in the reconstruction of the shape of the condyle during healing of a sagittal fracture of the mandibular condyle. Twenty adult sheep were divided into 2 groups: all had a unilateral operation on the right side when the anterior and posterior attachments of the discs were cut, and an oblique vertical osteotomy was made from the lateral pole of the condyle to the medial side of the condylar neck. Ten sheep had the lateral pterygoid muscle cut, and the other 10 sheep did not. Sheep were killed at 4 weeks (n=2 from each group), 12 weeks (n=4), and 24 weeks (n=4) postoperatively. Computed tomograms (CT) were taken before and after operations. We dissected the joints, and recorded with the naked eye the shape, degree of erosion, and amount of calcification of the temporomandibular joint (TMJ). In the group in which the lateral peterygoid muscle had not been cut the joints showed overgrowth of new bone and more advanced ankylosis. Our results show that the lateral pterygoid muscle plays an important part in reconstructing the shape of the condyle during the healing of a sagittal fracture of the mandibular condyle, and combined with the dislocated and damaged disc is an important factor in the aetiology of traumatic ankylosis of the TMJ.     

Experiences with pins and rubber band traction in the treatment of proximal interphalangeal joint contracture

BACKGROUND:

Proximal interphalangeal joint (PIPJ) contracture is a difficult problem to treat regardless of etiology. Although numerous interventions have been recommended, published results are mediocre at best.

OBJECTIVE:

The authors describe their experience and results of using a modification of pins and rubber band traction (PRBT) – applying a dynamic extension apparatus to a contracted PIPJ using the constant traction force in a stretched rubber (elastic) band.

METHOD:

A retrospective review of patients treated with this method was performed, and the results are presented. The technique itself is described, and clinical photographs illustrate the method.

RESULTS:

Mean PIPJ flexion contracture before PRBT was 82° (range 60° to 110°). The full correction of eight contracted PIPJs in seven patients was achieved, in a mean of 17.8 days (range 14 to 31 days). At one month postremoval of PRBT, the mean PIPJ flexion contracture was 22.8° (range 0° to 46°).

DISCUSSION:

The method is compared with previously described methods of PIPJ contracture correction, whether surgical or splinting; the latter may be static, dynamic or a combination of the two. The results of previously published studies are discussed and compared with the method described.

CONCLUSION:

The present method is a powerful and effective simplification of a previously described method of correcting PIPJ contractures. This technique is simple, ‘low-tech’ and can be applied under local anesthetic; the authors believe it offers a useful adjunct to surgical release.