Referral indications and prevalence of sleep abnormalities in children with early onset scoliosis.

This study describes the utility of overnight sleep studies in children with early onset scoliosis (EOS). Children with EOS have diminished respiratory reserve which is associated with abnormal breathing and sleep quality in children. Currently, there are no criteria for referral of these children to evaluate breathing during sleep or data on the use of sleep treatments as part of their supportive care. A review of the 159 patients with EOS who were followed at a single institution from 2003 to 2016 identified 68 who underwent overnight polysomnograms (PSGs). Sixty-five of 68 (96%) had elevated apnea-hypopnea index (AHI) and a majority (56%) were prescribed nighttime respiratory support. A majority of young children (< 5 years) with PSG were referred for a history of snoring, apnea, or restless sleep; all 30 had abnormal PSGs. Twenty-seven (90%) had nighttime hypoxemia (nadir oxygen saturation values < 92%). Eighteen (60%) were referred to otolaryngology, of whom 11 (37%) subsequently underwent tonsil and/or adenoid removal. In older children (≥ 5 years), those referred for PSGs had more severe restrictive chest wall disease [lower forced vital capacity (FVC) values] than those who were not sent for PSG. Correlation between FVC and apnea-hypopnea index, however, was not significant. Pre-operative coronal curve magnitude did not strongly correlate with nadir SaO2 or AHI in either age group. These results suggest that sleep studies are underutilized in the management of children with EOS. Inadequate and poor-quality sleep adversely affects growth, behavior, and cognitive function in children. This study suggests that screening for sleep abnormalities should be incorporated into assessment and treatment of more patients with EOS.

Patient factors associated with delayed diagnosis of developmental dysplasia of the hip.

PURPOSE: Early detection and intervention for developmental dysplasia of the hip (DDH) is important for normal hip development. Previous studies have shown disparities in access to paediatric specialty care among different racial and socioeconomic backgrounds. This study aims to identify whether these factors are related to timely referral for infants with DDH. METHODS: A retrospective cohort study of patients seen and treated for DDH between July 2006 and June 2011 at a single institution were reviewed. The patients were divided into early-presenting (seen before six months of age) and late-presenting patients (seen at six months of age or later). RESULTS: A total of 457 patients met the eligibility criteria. There were 378 early and 79 late presentations. Late presentations were significantly more likely to be vertex at birth (85% vs 41%, p < 0.001). Bivariate analysis also demonstrated that late presentations were more likely to be non-white (65% vs 45%, p = 0.004), non-English speaking (20% vs 8%, p = 0.003), from lower income areas ($70 769 vs $61 591, p < 0.001) and hold public insurance (25%, p = 0.001). However, a logistic multiple regression analysis showed that only vertex birth presentation (p = 0.000), absent family history of DDH (p = 0.047) and affected right side (p = 0.001) were significantly associated with late presentation. CONCLUSION: Despite screening algorithms to facilitate early diagnosis of infants with DDH, better research is needed to understand how different demographic and socioeconomic factors play into the delayed access to paediatric orthopaedic care for DDH so that we may ultimately improve rates of early treatment.

In vitro comparison of transfixation and standard full-limb casts for prevention of displacement of a mid-diaphyseal third metacarpal osteotomy site in horses.

OBJECTIVE: To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. SAMPLE POPULATION: 6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system. PROCEDURE: A 30 degrees osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that incorporated the pins was applied. An extensometer was positioned in the osteotomy site through a window placed in the dorsal aspect of the cast, and after removal of the screws, displacement was recorded while the limb was axially loaded to 5,340 N (1,200 lb). Pins were removed, and the standard full-limb cast was tested in a similar fashion. RESULTS: The transfixation cast significantly reduced displacement across the osteotomy site at 445 N (100 lb), 1,112 N (250 lb), 2,224 N (500 lb), and 4,448 N (1,000 lb), compared with the standard cast. CONCLUSION AND CLINICAL RELEVANCE: A full-limb transfixation cast provides significantly greater resistance than a standard full-limb cast against axial collapse of a mid-diaphyseal third metacarpal osteotomy site when the bone is placed under axial compression. Placement of full-limb transfixation casts should be considered for the management of unstable fractures of the third metacarpal bone in horses.

Effect of three types of half-limb casts on in vitro bone strain recorded from the third metacarpal bone and proximal phalanx in equine cadaver limbs.

OBJECTIVE: To determine effect of 3 half-limb casts on bone strains recorded from the proximal phalanx (P-1) and third metacarpal bone (MCIII) of equine cadaver limbs, using a mechanical testing machine. ANIMALS: 12 equine cadaver limbs and 4 live horses. PROCEDURE: Bone strains were recorded at middorsal P-1 and the dorsal cortical aspect of the distal third of MCIII while limbs were variably loaded with 100 to 1,000 lb of force. To determine ability of the cast to protect the distal portion of the limb from weight-bearing loads, strains were recorded with the limb in 1 of the 3 casts and with it unsupported. To determine cast-induced discomfort, weight-supporting and transfixation pin casts were evaluated on 2 live horses RESULTS: All 3 casts significantly reduced bone strain at P-1. Significant differences were observed: mean 61% reduction for the standard half-limb cast, 84% for the transfixation pin cast, and 97% for the weight-supporting cast at weight-bearing force of 500 lb. Only the weight-supporting cast significantly reduced strains recorded from MCIII. The weight-supporting cast was not well tolerated by 2 live horses. CONCLUSIONS: The 3 casts significantly reduced transfer of weight-bearing forces to the distal portion of the limb. The weight-supporting cast effectively reduced strain on the P-1 to near 0, but was well tolerated by live horses. The transfixation pin cast reduced strain on the P-1 by > 80% at weight-bearing loads of 500 lb, and live horses were comfortable. Standard half-limb casts significantly reduced strains on the P-1, but to a lesser degree than did other casts.

Effect of different full-limb casts on in vitro bone strain in the distal portion of the equine forelimb.

OBJECTIVE: To determine the ability of a full-limb transfixation pin cast to protect the distal portion of the equine forelimb from weight-bearing forces by measuring bone strain in vitro on cadaver limbs loaded in a mechanical testing machine. SAMPLE POPULATION: 6 forelimbs from 6 horses. PROCEDURE: Each limb was instrumented with 3 unidirectional metal foil electrical resistant strain gauges. Gauges were placed on the dorsal aspect of the distal portion of the radius and the mid-dorsal portion of the cortex of the third metacarpal bone and the first phalanx. Each limb was tested 3 times, once supported with a transfixation pin cast, once supported by a standard full-limb cast, and finally, uncast. The limbs were tested in a mechanical testing machine under axial loads ranging from 100 to 1,000 lb, and bone strains were recorded at each load. RESULTS: Compared with values for the uncast limb, the transfixation pin cast and the standard full-limb cast significantly (P < 0.001) reduced bone strain on the distal portion of the radius, third metacarpal bone, and first phalanx. Compared with the standard full-limb cast, the transfixation pin cast significantly (P < 0.001) reduced bone strain on the first phalanx. CONCLUSION AND CLINICAL RELEVANCE: Compared with the standard full limb cast, the full-limb transfixation pin cast is more protective of the first phalanx.

Effect of pin hole size and number on in vitro bone strength in the equine radius loaded in torsion.

OBJECTIVE: To determine the effect of pin hole size and number on the breaking strength of the adult equine radius when loaded in torsion to failure. SAMPLE POPULATION: 54 pairs of equine radii from adult horses. PROCEDURE: For test one, 12 pairs of radii were used to determine the effect of pin hole size on torsional breaking strength. A 6.35-mm hole was drilled in 1 radius, and a 9.5-mm hole was drilled in the contralateral radius. For test two, 36 pairs of radii were randomly assigned to 1 of 3 treatment groups (n = 12) to determine the effect of pin hole number on the torsional breaking strength of the equine radius. One radius of each pair served as a control, and one, three, or six 6.35-mm transcortical holes were drilled in the contralateral radius. For test three, 6 pairs of radii had torsional forces applied directly to the transfixation pins, as opposed to the bone itself. One radius of a pair served as a control, and three 6.35-mm smooth Steinman pins were placed in the contralateral radius. All radii were loaded in torsion to failure, and the breaking strengths were recorded. RESULTS: Compared with the 6.35-mm hole, the 9.5-mm hole significantly decreased torsional strength of the radius. There was no significant difference in mean torsional strength between the control radii and the radii with 1, 3, or 6 transcortical holes or when the transfixation pins were loaded. CONCLUSION: Use of up to three 6.35-mm transfixation pins can be used in a full-limb transfixation pin cast to optimize stiffness without a significant decrease (12%) in bone strength.

Influence of form and quantity of selenium on the development and survival of an insect herbivore.

Even plants classified as 'nonaccumulators' can sequester concentrations of sodium selenate, sodium selenite, selenocystine and selenomethionine that can strongly influence insect development and survival. These forms of selenium (Se), tested in diet-incorporation bioassays, proved toxic to larvae of a generalist insect herbivore at relatively low levels. Sodium selenite was the most toxic form tested against Spodoptera exigua (Hübner), with an LC(50) of 9.14 microg g(-1) wet wt (21.11 microg g(-1) dry wt). Selenocystine was intermediate with an LC(50) of 15.2 microg g(-1) wet wt. The least toxic forms, sodium selenate and selenomethionine, had LC(50)s below 50 microg g(-1) dry wt, the upper level for tissues of plants classified as nonaccumulators. Ingestion of some forms of Se also affected growth and development. Increasing concentrations of sodium selenate and sodium selenite decreased pupal weight and added significantly to the time needed for development to the pupal and adult stages. The time required to complete the larval stage increased by over 25% and the time from egg to adult emergence was extended by 22% to nearly 30%. Selenocystine and selenomethionine did not significantly increase developmental times, even at concentrations that killed 90% or more of the test populations. Analyses of relative growth rate, relative growth index, and an analysis of covariance technique for measuring growth indicated that the form of Se affected growth rates, growth inhibition responses of the larvae, and toxicological effects. Thus, quantity and the form of Se accumulating in plants grown on Se-contaminated sites are likely to influence the population dynamics of insect herbivores. The implications of these results for the ecology of contaminated sites are discussed.

Toxicity of linear furanocoumarins toSpodoptera exigua: Evidence for antagonistic interactions.

The linear furanocoumarins psoralen, bergapten, and xanthotoxin were tested for toxicity to the beet armywormSpodoptera exigua (Hübner) under short ultraviolet (UVB) radiation. Increased dietary concentrations of each furanocoumarin significantly decreased insect larval weight, extended generation time, and induced higher mortality. Xanthotoxin was the most toxic, followed by psoralen and bergapten. Combining psoralen with bergapten, xanthotoxin, or both resulted in significantly antagonistic effects on insect mortality. The combination of bergapten and xanthotoxin, however, produced additive effects. The implications of these observations forS. exigua resistance in the wild plant accession ofApium prostratum and the enigma the findings represent for plant-insect relationships are discussed.

Lyme borreliosis in cattle and horses: a review of the literature.

A complete search of the literature concerning Lyme borreliosis as it relates to horses and cattle was done. The epidemiology, pathogenesis, immunological response to the disease, diagnosis and treatment are discussed. A review of clinical cases in horses and cattle is presented. Clinical signs of Lyme borreliosis in horses include: chronic weight loss, sporadic lameness, laminitis, low grade fever, swollen joints, muscle tenderness, and anterior uveitis. In addition to those clinical signs, neurological signs such as depression, behavioral changes, dysphagia, head tilt and encephalitis can be seen in chronic cases. Borreliosis occurs in cattle, usually as a herd problem. In acute Lyme borreliosis, cattle often will show a fever, stiffness, swollen joints, and decreased milk production. Chronic weight loss, laminitis and abortion are also possible outcomes of borreliosis in cattle. Diagnosis of clinical Lyme borreliosis is difficult and depends upon recognition of clinical signs, a history of possible exposure, and identification of the spirochete in the affected animal. Since the spirochete is very difficult to culture, confirmation of B. burgdorferi infection often relies on serologic testing. Subclinical seropositive animals do occur, thus confusing the diagnosis. An approach to treatment of cattle and horses with Lyme borreliosis is outlined.

Suspensory apparatus prosthesis in the horse. Part 1: In vitro mechanical properties.

Mechanical properties of equine suspensory apparatus preparations and three braided synthetic prostheses were evaluated in vitro. Force versus displacement plots and failure modes were recorded from single load-to-failure testing in 18 cadaver limbs before and after replacement of each suspensory apparatus with a prosthesis. Mean load at failure, energy to failure, and stiffness values of polytetrafluoroethylene (PTFE) prostheses were lower than those of the suspensory apparatus and aramid prosthesis. The PTFE prosthesis failed by elongation or rupture of the prosthesis. Mechanical properties of the aramid prosthesis with collar augmentation were not significantly different from the suspensory apparatus. The main site of failure in both aramid prostheses was at the screw fixation to bone.

Suspensory apparatus prosthesis in the horse. Part 2: In vivo evaluation in a suspensory apparatus disruption model.

The suspensory apparatus of one forelimb was surgically disrupted in six adult horses by transecting the distal sesamoidean ligaments. A double-braided prosthetic ligament made of aramid yarn was installed to support the flexor surface of the metacarpophalangeal joint. The prosthesis was routed through tunnels in the third metacarpal bone and proximal phalanx, and secured to bone with screws. Evaluation by radiography, synovial fluid analysis, cinematography, and dynamography was performed before surgery and at weeks 16 and 30. Supracondylar cortical lysis and periosteal proliferation were observed on postoperative radiographs. Synovitis and fragmentation of the prosthesis were apparent from synovial fluid evaluation. Weight bearing and metacarpophalangeal joint motion were decreased and loading was transferred in part to the opposite forelimb. Clinical lameness improved and weight bearing increased during the second half of the 30-week period. At necropsy, there was abrasion of the prosthesis and the articular surfaces in contact with the prosthesis. Diffuse granulomatous synovitis developed in response to aramid fiber fragments within the synovium.

Age effects on cytochrome oxidase activities during denervation and recovery of three muscle fiber types.

The rat nasolabialis muscle is comprised of a mosaic of red, white, and intermediate muscle fiber types. Using computerized microdensitometry, cytochrome oxidase (COX) activity was quantitatively analyzed in each fiber type throughout the period of denervation and recovery in young adult (3-month) and middle-aged (15-month) male Sprague-Dawley rats. In animals of both age groups, the nasolabialis muscle on one side of the head was denervated by crushing the facial nerve. At specific days post crush (dpc) ranging from 2 days-2 months, animals were sacrificed and thick sections of normal and denervated muscles were incubated to demonstrate the activity of COX, a mitochondrial enzyme, which differentiates between the three fiber types. Enzyme activities in individual fibers were microdensitometrically analyzed using a digitizing image analyzer. Although a denervation-induced decreased followed by eventual recovery occurred in all fibers of each type, age-related differences were evident. For all types, younger fibers consistently showed decreased COX activity sooner than their older counterparts, and older fibers of all types consistently showed a greater decreased COX activity than the younger fibers. Denervation-induced de-differentiation of muscle fibers led to a more homogeneous population of fiber types in both age groups. Following recovery of function, the magnitude of the fiber enzyme activity change differed according to fiber type and to age, and was consistently smaller in older animals. The normal mosaic pattern of fiber type distribution and normal COX levels were restored 2 months after nerve lesion in both age groups.

The effects of age on atrophy and recovery in denervated fiber types of the rat nasolabialis muscle.

This study investigates the effects of advancing age on responses of nasolabialis muscle fibers to denervation and reinnervation. The nasolabialis is innervated by the facial nerve and is responsible for the whisking movement of the animal's large vibrissae. In young adult (3-month) and middle-aged (15-month) rats the muscle on one side of the head was denervated by crushing the facial nerve. At specific days postcrush, animals were sacrificed and thick sections of muscle were incubated to demonstrate cytochrome oxidase activity, a mitochondrial enzyme, which differentiated between red, white, and intermediate fiber types. The rate and extent of atrophy and recovery were evaluated using light microscope morphometric methods for which transverse fiber areas were measured and compared to fibers on the contralateral control side. There was an age-related delay in the time of functional return since older animals resumed normal whisking behavior 6 days later than the younger animals. In both age groups, white and intermediate fibers atrophied to the greatest extent and red fibers showed least atrophy. Despite the different responses of the fiber types to denervation, there was no age difference in the maximum degree of fiber atrophy within each fiber type. Age differences did occur in the rate of the denervation response since the middle-aged fibers consistently showed a more rapid significant atrophy than the young adult fibers. During recovery, older fibers may be limited in their ability to attain the size of fibers on the control side. The results indicate that through middle age, the process of advancing age increases the susceptibility of the nasolabialis muscle to denervation but does not alter the maximum extent of atrophy. The ability to recovery to normal fiber size, at least 2 months after denervation, is also age-related.

Changes in equine carpal joint synovial fluid in response to the injection of two local anesthetic agents.

The effects of repeated arthrocentesis and injection of local anesthetic agents, lidocaine HCl or mepivacaine HCl on the equine middle carpal joint were investigated. Synovial fluid samples were evaluated before, and 12, 24 and 48 hours following, treatment. The greatest changes from pretreatment values occurred in synovial fluid cellularity. Repeated arthrocentesis caused a moderate increase in cell counts, while injection of local anesthetics caused a greater increase. Alterations in mucin clot quality, hyaluronic acid content, fluid viscosity, total protein and immunoglobulin G were generally of no significance. The most sensitive sampling time to detect changes caused by a given treatment was 24 hours following treatment while the 12 hour sampling period appeared to be the best at detecting differences between treatments. Repeated arthrocentesis has a definite effect on synovial fluid composition but the effects appear to decrease with repeated centesis. Lidocaine HCl and mepivacaine HCl are irritating to the synovial environment. Clear differences between responses to the drugs could not be identified.

A modified Cloward's technique for arthrodesis of the normal metacarpophalangeal joint in the horse.

A modified Cloward's technique was performed for arthrodesis of one metacarpophalangeal (MCP) joint in eight horses. Dorsal arthrotomies were performed medial and lateral to the common digital extensor tendon and two 16 mm holes were drilled through the joint. A perforated cylindrical stainless steel basket filled with cancellous bone was impacted into each hole. The limbs were supported in casts for 8 weeks. The joints were examined and radiographed at 4 weeks, 8 weeks, 6 months, and 10 months. One horse was euthanatized at week 14 to assess the progress of the arthrodesis. In the other seven horses, there was clinical fusion at month 6. Dynamographic evaluations were performed 11 months after surgery at the walk and trot. The maximum vertical forces exerted during weight bearing by treated and control limbs were compared. No difference was detected at the walk; however, a significant difference was present at the trot (p less than 0.05). It was calculated that at the trot the horses placed 90% as much force on the treated limb as on the control limb. Eleven months after surgery, the baskets contained compact and cancellous bone. Ingrowth of bone occurred through all openings, completely filling the baskets and fusing the joints.

Quality control in the blood bank.

In discussing quality assurance in the blood bank, where many of the standard statistical techniques of measuring accuracy simply do not apply, three questions come to mind: How much? How often? Who says? Because of severe changes in the prospective payment plan and a new interest in cost effectiveness, many transfusion services are re-examining blood banking methodologies and their relative usefulness in promoting patient well-being. Many serologists are beginning to say that "less is better." This concern for simplification and reduction of workload is reflected in the quality control.

Diaphyseal angular deformities in three foals.

Angular limb deformities in 3 foals were found to originate in the diaphyseal region of the 3rd metacarpal (2) and metatarsal (1) bones. In each case, treatment consisted of wedge ostectomy followed by compression plating. Two foals survived for useful performance; the 3rd was euthanatized because of ischemia of the operated limb. The condition appeared to resemble a similar syndrome in man involving tibial curvature.

Six cases of squamous cell carcinoma of the stomach of the horse.

Six cases of squamous cell carcinoma of the stomach in horses seen at the New York State College of Veterinary Medicine are compared with 15 similar cases reported previously. Clinical signs included anorexia in all cases, emaciation, fever, anaemia and/or palpable abdominal masses in 3, colic in 2 and dysphagia in one case. Haematological studies revealed normochromic, normocytic anaemia in 3 and absolute neutrophilia in 5 cases. Peritoneal fluid analysis was performed in 4 cases and revealed slightly to moderately elevated total protein concentrations in 3 and a markedly elevated number of white blood cells in 2 cases. Exploratory laparotomy, performed in 3 cases, was essential for a definitive diagnosis. The data presented here suggest that squamous cell carcinoma of the equine stomach may be increasing in frequency and demonstrate the need for prospective epidemiological studies.