bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Positive Contrast Arthrography in Canine Cranial Cruciate Ligament Disease
Authors: Aron D.N. , Roberts R. , Stallings J. , Brown J. , Hay C.W.
Published: March 2018

Arthrographic and intraoperative evaluations of stifles affected with cranial cruciate disease were compared. Arthrography did not appear to be helpful in predicting cranial cruciate ligament pathology. The caudal cruciate ligament was consistently not visualized in the arthrograms and was normal at surgery. The menisci were visualized consistently in the arthrograms, but conclusions could not be made as to the benefit of arthrography in predicting meniscal pathology. Arthrography was not helpful in predicting joint capsule and femoral articular surface pathology. Survey radiographic evaluation was better than arthrography in evaluating joint pathology. When cruciate injury is suspected, after history and physical examination, survey radiographs are better than positive contrast arthrograms at supporting the diagnosis.

Positive contrast arthrography was evaluated as a diagnostic aid in canine cranial cruciate ligament disease. It did not appear to be useful in predicting joint pathology. With arthrography, both menisci could be visualized and evaluated for abnormalities. Joint effusion and presence of osteophytes evaluated on survey radiographs was better than arthrography in evaluating joint pathology.
Clinical Use of Ilizarov’s Compression Technique in the Treatment of a Septic Pseudoarthrosis in a Calf
Authors: Miscione H. , Redondo A. , David E. , Pistani J. R.
Published: March 2018

This article describes the use of the Ilizarov External Fixator Apparatus in infected suppurative pseudoarthrosis in a young calf.
Non-steroidal Anti-inflammatory Analgesics for Acute Pain Management in Dogs and Cats
Authors: Mathews Karol A.
Published: March 2018

The recently developed non-steroidal anti-inflammatory drugs, discussed in this article, have been shown to be efficacious in controlling post-operative pain, used either alone or in combination with opioids, in both cats and dogs. In some instances selected non-steroidal anti-inflammatory analgesics appear to confer superior analgesia to opioids after orthopedic surgery. However, the side-effects of these drugs are an important factor in selecting the appropriate candidate to receive these analgesics. The contra-indications for use of non-steroidal anti-inflammatory drugs should be strictly adhered to. The trade names listed in this article may differ from those used in individual countries. The reader is advised to consult their own pharmacopea for trade names in the individual’s own country.

Recently developed, parenteral NSAIAs have been shown to be effective in managing postoperative pain in cats and dogs. In some instances, individual NSAIAs are equal to, and may be better than, opioid agonists in treating moderate to severe post-operative or medical pain. However, due to the concern for renal failure, gastric ulceration with hemorrhage and hemostatic abnormalities with individual NSAIA administration, caution must be used when selecting patients to receive these analgesics. Indications, relative contraindications and absolute contraindications for NSAIA use are discussed. A pain assessment scale (p. 128) with descriptors and suggestions for pain management are also discussed.
Traumatic Coxofemoral Luxation in Dysplastic Dogs Managed with a Triple Pelvic Osteotomy: Results in four Dogs
Authors: Lewis D. D. , Kerwin S. C. , Murphy S. T.
Published: March 2018

Triple pelvic osteotomy (TPO) was used in the treatment for traumatic coxofemoral luxations in four adult, large breed dogs with hip dysplasia. Initial closed reductions failed in three and one dog had an initial closed reduction and subsequent open reduction of the coxofemoral luxation that failed. Hip dysplasia was thought to be a prominent factor contributing to the reluxation. TPO successfully maintained reduction of the coxofemoral luxation in all of the dogs. An increase in dorsal acetabular coverage of the femoral head following TPO was demonstrated by an increased Norberg angle. The improved congruency was thought to maintain reduction of the femoral head in the acetabulum and decrease stresses on the joint capsule, allowing healing to occur. Long-term (median: 343, mean ± SD: 406 ± 226 days follow-up) function of the affected limb was comparable to the contralateral limb. Three of the four dogs did not have radiographic progression of coxofemoral degenerative joint disease of the affected joint and differences in the progression of degenerative joint disease were not evident between the affected and the contralateral coxofemoral joint. A decrease in abduction and external rotation and an increase in internal rotation following TPO was noted in the affected coxofemoral joint. Our results establish the utility of this procedure in dysplastic dogs with traumatic coxofemoral luxations.

Triple pelvic osteotomy used in the treatment for traumatic coxofemoral luxation in four adult, large breed dogs with hip dysplasia successfully maintained reduction and resulted in satisfactory limb function in all patients.
Heat Conduction of Fixator Pins with Polymethylmethacrylate External Fixation
Authors: Tomlinson J. L. , Hahn A. W. , Constantinescu G. M. , Wagner-Mann Colette , Williams N.
Published: March 2018

The purpose of this study was to determine the degree of thermal conduction along the fixation pins associated with acrylic external fixators and to develop a means of minimizing the potential for thermal injury. The data suggest that the degree of temperature conducted with 1.9 cm diameter acrylic external fixators was of minimal clinical significance if maintained a distance of one centimeter from the patient’s tissues. Larger diameter columns increase the potential for injury, however, this can be minimized with the use of a constant saline drip at the pin-acrylic interface to facilitate heat loss.

This article describes the evaluation of thermal properties of polymethylmethacrylate external skeletal fixators. The data demonstrate heat conduction along the fixation pins. Thermal injury is theoretically minimized if columns are maintained a distance of at least one centimeter from the patient’s tissue.

Research supported in part by and presented for the University of Missouri Pi Chapter of the Honor Society of Phi Zeta in coordination with SmithKline Beecham Animal Health, April 7, 1994
The Microvascular Carpal Foot Pad Flap: Results in Three Clinical Cases
Authors: Moens Noel M. M. , Fowler J. David
Published: March 2018

Four microvascular carpal foot pad transfers were performed on three dogs for reconstruction of weight bearing surfaces. All of the dogs had suffered severe trauma to the major weight bearing foot pads of at least one foot due to: burn injury (one dog), ischaemic injury (one dog) or sharp trauma (one dog). The vascular anatomy of the carpal foot pad flap was consistent in all of the dogs. The arterial pedicle arose from the caudal interosseous artery and the venous effluent drained via the cephalic vein. All of the flaps survived transfer. Post-operative care included heavily padded bandages and daily visual assessment of flap viability. All of the flaps developed partial wound dehiscence along their distal borders, presumably due to incisional stresses from weight bearing. The flaps were surgically repositioned as necessary in order to maintain a central weight bearing position. Ultimately, all of the flaps healed and hypertrophied to accomodate weight bearing stresses. In all dogs functional results were good.

Foot pads are highly specialized to withstand the hostile environments into which they are placed. Reconstruction of weight bearing surface following loss of foot pads, therefore, is difficult. Microvascular free transfer of foot pads allows the reconstruction of such deficits with tissue that is, anatomically, most appropriately suited to adopt the function of weight bearing. Microvascular free transfer of the carpal foot pad flap for foot reconstruction is demonstrated in three clinical cases.
Fatigue Study of Six and Eight mm Diameter Interlocking Nails with Screw Holes of Variable Size and Number
Authors: Vanderby R. , McCabe R. P. , Dueland R. T.
Published: March 2018

Clinical fatigue failure of 6 mm diameter interlocked nails (ILN) with holes accommodating 3.5 mm screws has been reported. This problem was investigated by testing eight different designs of 6 mm and 8 mm diameter ILN with a 2 plus 2 screw hole pattern and a multiple holed pattern. Interlocking nails with holes to accommodate 3.5 and 4.5 mm screws in 8 mm ILN and 2.7 and 3.5 mm screws in 6 mm diameter ILN were used. A rotating beam testing device produced uniform bending moments across a test region of the ILN containing at least two holes. These moments fully reversed with each cycle. Fatigue failure occurred through screw holes. Using statistical modeling, reduction of the 6 mm ILN hole size from accommodating 3.5 screws to 2.7 mm screws increased the estimated fatigue life (EFL) of the latter by 52 times, comparable to the EFL of the 8 mm ILN with 4.5 screw holes. Reducing the 8 mm ILN screw hole size from accommodating 4.5 screws to 3.5 mm screws increased the comparative EFL by eight times. Fatigue testing is a good method to compare fatigue behavior of various implant designs. This gives a surgeon more information when selecting an ILN for fracture fixation.

Occasional breakage of interlocking nails (ILN) in clinical cases prompted fatigue testing of original ILN and new designs of ILN. This study documented base line fatigue resistance information of the various ILN designs. Results indicated smaller screw holes markedly increased the fatigue resistance of both 6 mm and 8 mm diameter ILN. This information will aid the surgeon in planning fracture treatment.
Evaluation of Stiffness and Stress of External Fixators with Curved Acrylic Connecting Bars
Authors: Shahar R.
Published: March 2018

The use of acrylic connecting bars in external fixators has become widespread in veterinary orthopaedics. One of the main advantages of an acrylic connecting bar is the ability to contour it into a curved shape. This allows the surgeon to place the transcortical pins according to safety and convenience considerations, without being bound by the requirement of the standard stainless steel connecting bar, that all transcortical pins be in the same plane.

The purpose of this study was to evaluate the stiffness of unilateral and bilateral medium-sized external fixator frames with different curvatures of acrylic connecting bars. Finite element analysis was used to model the various frames and obtain their stiffness under four types of load: Axial compression, four-point medio-lateral bending, fourpoint antero-posterior bending and torsion. The analysis also provided the maximal pin stresses occurring in each frame for each loading condition.

Based on the results of this study, curvatures of acrylic connecting bars of up to a maximal angular difference between pins of 25° will result in very similar stiffness and maximal pin stresses to those of the equivalent, uniplanar stainless steel system. In both unilateral and bilateral systems the stiffness decreases slightly as angulation increases for axial compression and medio-lateral bending, increases slightly for torsion and increases substantially for antero-posterior bending.

External fixator systems with curved acrylic connecting bars are commonly used in veterinary orthopaedics. This paper evaluates the biomechanical performance of such systems by applying the finite element analysis method. It shows that external fixators with curved acrylic connecting bars exhibit stiffness and maximal pin stresses which are similar to those of the standard stainless steel system.
A Comparative Study of the Length Patterns of Anterior Cruciate Ligament Reconstructions in the Dog and Man
Authors: Andrish J. T. , Olmstead M. L. , Kambic Helen , Shah A. , Palmisano M. P.
Published: March 2018

To measure the change of length patterns of nine different simulated anterior cruciate ligament (ACL) reconstructions in the canine and human knee.

Six fresh-frozen canine cadaver knees and six fresh-frozen human cadaver knees were used in this study. All of the soft tissues were removed from each cadaver knee, leaving the menisci, collateral ligaments and cruciate ligaments intact. After fixation of the femur to a custom-made frame, the ACL was excised. Three tunnels were made each at the ACL origin and insertion, making possible nine reconstruction combinations. A modified intra-articular technique was used to measure change of length, in mm, of each ACL reconstruction through a range of motion of 0 degrees (full extension) to 135 degrees of flexion. A rankorder list of reconstruction combinations was determined. The most isometric combination was determined for the canine and human knees, and trends in length patterns were also evaluated in both species relative to femoral and tibial position. Statistical significance was determined by ANOVA.

A combination joining a point caudal to the ACL origin (over-the-top) and anterior on the tibial insertion was found to be the most isometric combination in both the canine and human. The trends in change of length patterns across all reconstruction combinations were similar in the dog and man. Isometry was improved as the reconstruction was placed further posterior on the femur and anterior on the tibia. Conclusions: The canine knee is an appropriate animal model for the study of isometry of the human ACL and its reconstructions.

The length patterns of nine simulated Anterior Cruciate Ligament (ACL) reconstructions were determined in the dog and man. In both species, the most isometric reconstruction was one joining points corresponding to a position at the posterior edge of the intercondylar roof of the femur (over-thetop) with a position anterior on the ACL insertion. For the sake of clarity the term anterior cruciate ligament has been used, throughout, for both species, instead of the cranial cruciate ligament (CCL) in the dog. Also knee has been used in place of stifle for the dog.
Antibiotic prophylaxis in veterinary orthopaedic surgery
Authors: Budsberg S. C. , Kirsch J. A.
Published: March 2018

Antibiotic prophylaxis is widespread in veterinary and human surgery. Key principles must be followed in case selection, drug choice and administration to ensure maximal effectiveness. More prospective clinical trials in veterinary orthopaedics are needed to better define which patients and which procedures will benefit from antimicrobial prophylaxis.
Effects of wire tension on the biomechanics of asymmetric four-ring circular external skeletal fixator constructs
Authors: Lewis D. D. , Rigaud S. , Mackinzie G. B. , Rapoff A. J. , Cross A. R.
Published: March 2018

This study evaluated the effects of fixation wire tension (0 kg, 30 kg, 60 kg, and 90 kg) on the biomechanics of a four ring asymmetric circular external fixator construct in four testing modes (axial compression, medio-lateral bending, craniocaudal bending, and torsional loading) using a gap fracture model. Wire tension had a significant direct effect on gap stiffness in all of the testing modes. Axial compression load-deformation curves exhibited non-linearity, characteristic of the self-tensioning effect observed with fine wire fixation. Bending loaddeformation curves had two discrete linear segments, attributable to slipping of the bone models on the fixation wires, once a critical bending moment was exceeded. Torsional loading caused a gradual ‘windup’ of the construct which was followed by a linear load-displacement curve. Increasing wire tension had a small but significant effect on gap stiffness, which generally diminished as higher tensions were applied, thus demonstrating the need for adequate initial construct design to achieve sufficient stability during fracture healing.
Influence of the connecting rod on the biomechanical properties of five external skeletal fixation configurations
Authors: Ross J. D. , Toombs J. P. , Welch R. D. , Bronson D. G.
Published: March 2018

A recently developed external skeletal fixation system (SK™, IMEX Veterinary, Inc.) utilizes larger diameter connecting rods, therefore overcoming one of the weaknesses of the original Kirschner-Ehmer (KE) system. The purpose of the current study was to compare five typical external fixator constructs in axial compression, torsion, Cranial-Caudal (C-C) and Medial-Lateral (M-L) bending to determine the effect of the larger connecting rods on frame stiffness. The results demonstrate that the larger connecting rod has a significant effect on overall frame stiffness. The use of two or more full-pins, as in the type II and III techniques nullified the contribution of the connecting rod diameter and frame stiffness was more a factor of pin size, number and orientation.
Microdamage at the pin-bone interface of external skeletal fixation pins after short-term cyclical loading
ex-vivo
Authors: Cohen K. , McCabe R.P. , Kalscheur V.L. , Vanderby R. , Markel M.D. , Muir P.
Published: March 2018

This study determined microdamage associated with external fixation pin insertion and short-term cyclical loading, using an ex vivo ovine tibial model. Orthofix tapered blunt-tipped 3.5/4.5 mm fixation pins and Apex® self-drilling self-tapping fixation pins, 4 mm in diameter, were used. After insertion, the constructs were either loaded in cantilever bending or not loaded. Constructs were then bulk-stained in basic fuchsin, and calcified sections were made. The sections were reviewed qualitatively and the microcrack surface density (Cr.S.Dn, μm/mm2) was quantified at the pin-bone interface. The pattern and quantity of microdamage induced was significantly influenced by fixation pin design and cortical region within the cisor transcortex, but not short-term cyclical loading. Overall, Cr.S.Dn was significantly increased with use of the Orthofix fixation pin (P < 0.01). Cr.S.Dn was also increased in the medial cis-cortex, compared with the lateral transcortex (P < 0.05). Diffuse damage within the medial cis-cortex was higher with the Orthofix pin. In contrast, the Howmedica Apex® fixation pin caused fracture of the periosteal region of the lateral transcortex, but relatively little microdamage within the medial cis-cortex. In this model as a consequence of pin insertion, fixation pin design had significant specific damage effects on both the medial cis-cortex and the lateral trans-cortex
Assessing the efficacy of long-term administration of Tolfenamic acid in dogs undergoing femoral head and neck excision
Authors: Dupuis J. , Moreau M. , Daminet S. , Hébert P. , Grisneaux E. , Charette B.
Published: March 2018

Femoral head and neck excision (FHNE) is a salvage procedure routinely performed when severe osteoarthritis is present and clinical signs cannot be managed by conservative treatment, or when total hip replacement is cost prohibitive for the owners. The purpose of the study reported herein was to evaluate the adverse effects and efficacy of long-term administration of Tolfenamic acid in dogs undergoing FHNE. Twenty dogs admitted with clinical signs associated with bilateral hip degenerative joint disease and weighing more than 20 kg were included in the study. Ten dogs received Tolfenamic acid for four months following FHNE and 10 dogs received a placebo. At four months after surgery, the placebo group had a significant decrease, compared with pre-operative values, in peak vertical force (PVF) (60.38% BW vs 64.77% BW, p = 0.046), and a significant decrease in vertical impulse (VI) (8.38% BW x sec. vs 9.64% BW x sec., p = 0.023). There was not any significant difference between pre- and post-operative results in the Tolfenamic acid group regarding PVF (65.13% BW vs 63.31% BW, p = 0.296) and VI (8.24% BW x sec. vs 8.71% BW x sec., p = 0.945). A significant difference was not found between the two groups with regard to endoscopic evaluation of mucosal lesions. Subjectively, the owners of the dogs in the Tolfenamic acid group reported an earlier use of the limb, a more compliant dog during physical therapy and a more rapid return to a ‘normal’ gait. Long-term administration of Tolfenamic acid may therefore be recommended, following FHNE, to improve the results of the operation.
Antebrachiocarpal luxation in a cat
Authors: Geyer H. , Montavon P. M. , Voss K.
Published: March 2018

A complete palmar antebrachiocarpal luxation due to rupture of the medial collateral ligament was diagnosed in a cat. Complete antebrachiocarpal luxation in dogs is generally associated with the disruption of multiple carpal ligaments. A comparative anatomical study of cadavers of five cats and five dogs revealed that, unlike in dogs, the medial collateral ligament in cats consists of only one branch, which extends from its dorsoproximal attachment on the radius obliquely to its palmarodistal attachment on the radial carpal bone. The oblique course of the ligament likely opposes palmar dislocation of the radial carpal bone rather than medial opening of the radiocarpal joint.

In this present reported case, adequate joint stability was achieved by replacing the medial collateral ligament using two 1.5-mm cortical screws and a

3.5 (metric gauge) polypropylene figure-8 suture sling. Minimal signs of osteoarthrosis developed three months after surgery, but functional outcome at six months was very satisfactory.
Quantification of histomorphometric and structural bone changes in a sheep model for fracture treatment in osteoporotic bone
Authors: Winterstein E. , Eckhardt C. , Rahn B. , Goldhahn J. , Schneider E. , Lill C. A.
Published: March 2018

The histomorphometrical cancellous bone parameters of osteoporotic ewes were examined to establish a large animal model for the investigation of fracture treatment and healing in osteoporotic bone. Eighteen animals were divided into 2 groups. Group 1 (n = 8, age 3 to 5 years) served as an untreated control. In Group 2 (n = 10, age 7 to 9 years) osteoporosis was induced by means of ovariectomy, methylprednisolone application (average dose 160 mg/week) and Ca./Vit.D restricted diet during 7 months. Biopsies from iliac crest, femoral head and lumbar spine were harvested. Structural parameters from the biopsies were determined using μCT. In order to investigate static and dynamic parameters of bone remodelling, undecalcified sections were digitized and evaluated by means of image analysing software. Morphologically, bone area and trabecular thickness were reduced in osteoporotic sheep. Bone perimeter (−20%), trabecular number (−16%) and separation (+39%) showed a significant change in the iliac crest. The structure model index indicated a shift from the plate-to the rodmodel. At different skeletal sites of osteoporotic sheep bone resorption was significantly increased (250-675%), and bone formation significantly decreased (77-89%). Osteoid thickness (O.Th) was reduced (28-62%). In osteoporotic sheep the mean length of single labels was significantly shortened (64-73%) and the mineralising surface showed a significant decrease (80-92%). The mineralisation of the osteoid was comparable to the control group. The histomorphometrical changes in this sheep model of osteoporosis are comparable to the human situation of a combined post-menopausal and steroid-induced osteoporosis.
A Scintigraphic Investigation of Magnetic Field Therapy on the Equine Third Metacarpus
Authors: Johnston G. R. , Lauper Linda , Kobluk C. N.
Published: March 2018

Scintigraphy was performed in the vascular, soft tissue and bone phase to demonstrate increased blood flow resulting from the local application of a permanent magnetic pad on the equine third metacarpus using a crossover trial in eight horses.

The results of the vascular phase showed a highly significant (p <0.01) increase in counts associated with magnet application. An increase in counts results from increased blood flow carrying more radionuclide to the area investigated. Fifteen of the sixteen limbs tested showed an increased vascular response. The soft tissue phase had a highly significant response (p = 0.01) with thirteen of the sixteen limbs showing increased activity. The bone phase also had a highly significant response (p <0.01) with fourteen of the sixteen limbs showing increased activity.

This study shows that the Equinepad® applied to the third metacarpus of the horse increases the circulation and metabolic activity of the soft tissue and bone. These effects show some variability in degree and occur in the majority of limbs tested.

Scintigraphy was performed in the vascular, soft tissue and bone phase using a cross over trial to demonstrate increased blood flow and metabolic activity as a result of the local application of a permanent magnetic pad on the equine metacarpus. A highly significant increase was evident in the three phases.
In Vitro Comparison of the Krackow and Locking Loop Suture Patterns for Tenorrhaphy of Flat Tendons
Authors: Barnes S. L. , Wenzel J. G. W. , Milton J. L. , Terry G. C. , Montgomery R. D.
Published: March 2018

Tenorrhaphy of 20 pairs of canine patellar tendons, was by a modification of the Krackow suture pattern on one of the pair and a single locking loop suture pattern on the contralateral tendon. The tenorrhaphies were pulled apart at a rate of 127 cm/min. The mode of failure for all tendons was disruption of the tendon and the suture material pulling out of the tendon. The mean maximum load for the locking loop suture pattern was 67.2 N (S.D. 7.8), compared to 61.3 N (S.D. 9.3) for the modified Krackow suture pattern. The mean energy absorbed to maximum load was 0.54 Joules (J) (S.D. 0.168) for the locking loop and 0.37 J (S.D. 0.12) for the modified Krackow. The mean stiffness was 4846 N/m (S.D. 803) for the locking loop and 5573 N/m (S.D. 921) for the modified Krackow.

This study indicated the locking loop suture pattern was significantly better than the modified Krackow suture pattern in maximum strength (p = 0.03), total energy absorbed to failure (p = 0.0004) and stiffness (p = 0.004). Both suture patterns are suitable for use in flat tendons or ligaments based on their maximum strength. However, the effect of the modified Krackow suture pattern on vascularity and healing has not been evaluated.

The locking loop suture pattern proved to be significantly better than the modified Krackow suture pattern in maximum strength, total energy absorbed to failure and stiffness.
The Energy Absorption Capacity of Equine Support Bandages
Authors: Vanderby R. , Neirby D. , Nordheim E. V. , Libbey C. J. , Crawford W. H.
Published: March 2018

Support bandages are placed on the distal limbs of horses to provide protection to the flexor tendons and suspensory ligaments during athletic activity. In this study, an equine cadaver leg model was used to measure the energy absorption capacity and the rate of energy absorption capacity loss of support bandages. Five different configurations of bandages were applied to the limb at two degrees of applications tension. In all configurations and at both tensions, bandaged legs absorbed significantly more energy than non-bandaged legs. Significant differences existed between bandage configurations in their ability to absorb energy. In addition, the effect of application tension on the energy absorption capacity of a bandage was found to be highly significant. The ability of a bandage to absorb energy declined over a 45 cycle trial. However, significant differences between bandage configurations in this respect were not found unless the bandage material was applied at full stretch tension. When the bandages were constructed with higher application tensions the rate of lost energy absorption capacity of the bandages was increased. The importance of bandage configuration and application tension for clinical use is discussed.

An equine cadaver leg model was used to measure the energy absorption capacity and the rate of energy absorption capacity loss of support bandages.
Prophylactic Antibiotics, Friend or Foe
Authors: Holmberg D. L.
Published: March 2018

The hazards from the routine use of antibiotics are outlined.
In Vitro Strain Patterns of the Intact Equine Metacarpus and Metatarsus Following Plate Luting
Authors: Cordey J. R. , Nunamaker D. M. , Tate M. L. , McIff T. , Perren S. M. , Turner A. S.
Published: March 2018

With internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.

Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.
A Sequential Method for Discovering Probabilistic Motifs in Proteins
Authors: Fotiadis D. I. , Likas A. , Blekas K.
Published: March 2018

Objectives:
This paper proposes a greedy algorithm for learning a mixture of motifs model through likelihood maximization, in order to discover common substrings, known as motifs, from a given collection of related biosequences.

Methods:
The approach sequentially adds a new motif component to a mixture model by performing a combined scheme of global and local search for appropriately initializing the component parameters. A hierarchical clustering scheme is also applied initially which leads to the identification of candidate motif models and speeds up the global searching procedure.

Results:
The performance of the proposed algorithm has been studied in both artificial and real biological datasets. In comparison with the well-known MEME approach, the algorithm is advantageous since it identifies motifs with significant conservation and produces larger protein fingerprints.

Conclusion:
The proposed greedy algorithm constitutes a promising approach for discovering multiple probabilistic motifs in biological sequences. By using an effective incremental mixture modeling strategy, our technique manages to successfully overcome the limitation of the MEME scheme which erases motif occurrences each time a new motif is discovered.
Decreased Fractal Correlation in Diurnal Physical Activity in Chronic Fatigue Syndrome
Authors: Ohashi K. , Bleijenberg G. , Werf S. , Prins J. , Amaral L. A. N. , Natelson B. H. , Yamamoto Y.
Published: March 2018

Objectives:
Our objectives were to study the temporal correlation of physical activity time series in patients with chronic fatigue syndrome (CFS) during normal daily life and to examine if it could identify the altered physical activity in these patients.

Methods:
Fractal scaling exponents of diurnal and nocturnal physical activity time series in 10 CFS patients and 6 healthy control subjects (CON) were calculated by the detrended fluctuation analysis (DFA) and the wavelet transform modulus maxima (WTMM) method. We hypo-thesized that, due to their illness- and/or fatigue-induced resting episodes, altered physical activity patterns in CFS patients might be observed at the interruption of activity bursts. Thus, we further developed a new method, the wavelet transform negative modulus maxima (WTNMM) method, which could evaluate the temporal correlation at the interruption of activities. We compared the fractal scaling exponents for CFS and CON by each method.

Results:
Both for CFS and CON, we found the fractal time structures in their diurnal physical activity records for at least up to 35 minutes. No group difference was found in nocturnal activities. The WTNMM method revealed that, in diurnal activities, CFS patients had significantly (p <0.01) smaller fractal scaling exponent (0.87 ± 0.03) compared to controls (1.01 ± 0.03). Such a difference was identified neither by the DFA nor WTMM method.

Conclusions:
CFS patients had more abrupt interruptions of voluntary physical activity during diurnal periods in normal daily life, probed by the decreased correlation in the negative modulus maxima of the wavelet-transformed activity data, possibly due to their exaggerated fatigue.
Fetal Heart Rate Variability due to Vibroacoustic Stimulation: Linear and Nonlinear Contribution
Authors: Signorini M. G. , Arduini D. , Cerutti S. , Magenes G.
Published: March 2018

Objectives:
This work aims at characterizing the variation of fetal heart rate (FHR) provoked by vibro-acoustic stimulation (VAS). The FHR signal is analyzed by means of a multiparametric approach consisting of linear and nonlinear indices.

Methods:
The FHR signals of 13 fetuses were collected through a US standard CTG monitor (HP1351A) and were sampled at a frequency of 2 Hz. The VAS was provided after a period of quiet of 10 minutes. The analysis was performed on the quiet period and on two successive time windows of 10 minutes each, after the stimulation. FHR classical parameters (delta, short term variability, long term irregularity, accelerations and decelerations) as well as power spectral density (PSD) and approximate entropy (ApEn) were computed for each period.

Results:
Results confirm that there is a significant change in fetal conditions after the stimulus is applied. This change can be clearly observed either in time domain parameters and in the regularity index (ApEn). Individual data are all consistent with an increase of variability and a decrease of regularity after VAS.

Conclusions:
The obtained results give further strength to the hypothesis that vibratory stimuli tests represent a reliable method for monitoring the neural development of the fetus during pregnancy.
Cortical Potential Imaging of Brain Electrical Activity by Means of Parametric Projection Filter
Authors: Lian J. , He B. , Hori J.
Published: March 2018

Objectives:
The objective of this study was to explore suitable spatial filters for inverse estimation of cortical potentials from the scalp electroencephalogram. The effect of incorporating noise covariance into inverse procedures was examined by computer simulations and tested in human experiment.

Methods:
The parametric projection filter, which allows inverse estimation with the presence of information on the noise, was applied to an inhomogeneous three-concentric-sphere model under various noise conditions in order to estimate the cortical potentials from the scalp potentials. The method for determining the optimum regularization parameter, which can be applied for parametric inverse techniques, is also discussed.

Results:
Human visual evoked potential experiment was carried out to examine the performance of the proposed restoration method. The parametric projection filter gave more localized inverse solution of cortical potential distribution than the truncated SVD and Tikhonov regularization.

Conclusion:
The present simulation results suggest that incorporation of information on the noise covariance allows better estimation of cortical potentials, than inverse solutions without knowledge about the noise covariance, when the correlation between the signal and noise is low.
Inclusion of Signal Analysis in a Hybrid Medical Decision Support System
Authors: Cohen M. E. , Meecham W. , Kramer M. , Hudson D. L.
Published: March 2018

Objectives:
Signal analysis has played an important role in cardiac diagnosis, both as a separate entity and in conjunction with clinical parameters. Hybrid systems are an effective method for developing higher-order decision models in which biomedical signal data can be incorporated.

Methods:
The hybrid system components include a knowledge-based system that utilizes approximate reasoning techniques, a neural network model based on a potential function approach to supervised learning that uses the general class of Cohen orthogonal functions as potential functions, and a signal analysis component that relies on continuous chaotic modeling to produce a degree of variability in the time series. The hybrid system is illustrated in an application for differentiation among different types of dementia.

Results:
Application of this method to cardiac diagnosis shows that chaotic parameters alone contribute significantly to correct classification while the addition of clinical parameters increases the sensitivity, specificity, and accuracy. Applications to electroencephalogram analysis indicate that the second-order difference plots display significant differences for the different types of EEG waves identifiable by frequency, both in shape and degree of dispersion. Hence the identification of these waves, and the duration of their occurrence, may provide suitable variables for chaotic analysis.

Conclusions:
Results from studies in cardiology demonstrate that using chaotic measures for ECG analysis provide useful information for classification. Sensitivity, specificity, and accuracy are increased if these methods are combined with other clinical parameters in a hybrid system. This approach has been extended to new applications based on EEG analysis combined with other relevant information.
EuCliD® – A Medical Registry
Authors: Amato C. , Carioni C. , Kirchgessner J. , Marcelli D. , Mitteregger A. , Moscardo V. , Orlandini G. , Gatti E. , Steil H.
Published: March 2018

Objectives:
The European Clinical Database EuCliD®
* has been developed as a tool for supervising selected quality indicators of about 200 European dialysis centers. Major efforts had to be made to comply with local and European laws regarding data security.

Method:
EuCliD® is a Lotus Notes® based flat-file database currently containing medical data of more than 14,000 dialysis patients from 10 European countries. Another 15,000 patients from 150 centers in 4 South-American countries will be added soon. Data are entered either manually or by means of interfaces to existing local data managing systems. This information is transferred to a central Lotus Notes Server. Data evaluation was performed with statistical tools like SPSS.

Results:
EuCliD® is used as a part of the CQI (Continuous Quality Improvement) management system of Fresenius Medical Care (FMC) dialysis units. Each participating dialysis center receives (currently every half year) benchmarking reports at a regular interval. The benchmark for all quality parameters is the weighted mean of the corresponding data of all centers.

Conclusions:
An obvious impact of data sampling and data evaluation on the quality of the treatments could be observed within the first one and a half years of working with EuCliD®. This also concerns important outcome predictors like Kt/V and hemoglobin concentration as the outcome itself expressed in hospitalization days and survival rates. With the help of EuCliD® the user is able to sample clinical data, identify problems, search for solutions with the aim of improving the dialysis treatment quality and guarantee a high-class treatment quality for all patients.
Content-based Image Retrieval in Medical Applications
Authors: Güld M. O. , Thies C. , Fischer B. , Spitzer K. , Keysers D. , Ney H. , Kohnen M. , Schubert H. , Wein B. B. , Lehmann T. M.
Published: March 2018

Objectives:
To develop a general structure for semantic image analysis that is suitable for content-based image retrieval in medical applications and an architecture for its efficient implementation.

Methods:
Stepwise content analysis of medical images results in six layers of information modeling incorporating medical expert knowledge (raw data layer, registered data layer, feature layer, scheme layer, object layer, knowledge layer). A reference database with 10,000 images categorized according to the image modality, orientation, body region, and biological system is used. By means of prototypes in each category, identification of objects and their geometrical or temporal relationships are handled in the object and the knowledge layer, respectively. A distributed system designed with only three core elements is implemented: (i) the central database holds program sources, processing scheme descriptions, images, features, and administrative information about the workstation cluster; (ii) the scheduler balances distributed computing; and (iii) the web server provides graphical user interfaces for data entry and retrieval, which can be easily adapted to a variety of applications for content-based image retrieval in medicine.

Results:
Leaving-one-out experiments were distributed by the scheduler and controlled via corresponding job lists offering transparency regarding the viewpoints of a distributed system and the user. The proposed architecture is suitable for content-based image retrieval in medical applications. It improves current picture archiving and communication systems that still rely on alphanumerical descriptions, which are insufficient for image retrieval of high recall and precision.
Evaluation of Computer-assisted Image Enhancement in Minimal Invasive Endoscopic Surgery
Authors: Vogt F. , Hohenberger W. , Paulus D. , Niemann H. , Schick C. H. , Krüger S.
Published: March 2018

Objectives:
This paper focusses on the evaluation of the usage of computer-aided image processing methods for minimal invasive surgery. During video endoscopy of visceral cavities the images are displayed directly on the monitor without further processing. In the course of the operation the former good quality of the images decreases due to typical disturbances like bleeding, smoke or flying particles. These disturbances can be reduced by using image processing methods like color normalization, temporal filtering or equalization.

Methods:
In this double-blinded analysis, 14 surgeons with different levels of experience evaluated 120 image pairs and 5 image sequences, directly comparing original and processed images or movies.

Results:
Color normalization and equalization proved to significantly enhance video endoscopic images. With regard to temporal filtering, an improvement could be seen in the image sequences with filter size 5 being a greater enhancement than filter size 3. Comparing the state of experience and its influence on the results, it occurred that the experienced surgeons preferred the original color while altogether agreeing that the color-normalized images were better.

Conclusions:
The results obtained in the present evaluation show that the image processing methods which were used can significantly improve the quality of video endoscopic images. As a result of this, necessary lavages of the operated area are reduced and a better overview and orientation for the surgeon can be reached.
Light Fields for Minimal Invasive Surgery Using an Endoscope Positioning Robot
Authors: Krüger S. , Schmidt J. , Paulus D. , Niemann H. , Hohenberger W. , Schick C. H. , Vogt F.
Published: March 2018

Objectives:
To generate a fast and robust 3-D visualization of the operation site during minimal invasive surgery.

Methods:
Light fields are used to model and visualize the 3-D operation site during minimal invasive surgery. An endoscope positioning robot provides the position and orientation of the endoscope. The a priori unknown transformation from the endoscope plug to the endoscope tip (hand-eye transformation) can either be determined by a three-step algorithm, which includes measuring the endoscope length by hand or by using an automatic hand-eye calibration algorithm. Both methods are described in this paper and their respective computation times and accuracies are compared.

Results:
Light fields were generated during real operations and in the laboratory. The comparison of the two methods to determine the unknown hand-eye transformation was done in the laboratory. The results which are being presented in this paper are: rendered images from the generated light fields, the calculated extrinsic camera parameters and their accuracies with respect to the applied hand-eye calibration method, and computation times.

Conclusion:
Using an endoscope positioning robot and knowing the hand-eye transformation, the fast and robust generation of light fields for minimal invasive surgery is possible.
HELEN, a Modular Framework for Representing and Implementing Clinical Practice Guidelines
Authors: Gausepohl H.-J. , Haak M. , Knaebel S. , Linderkamp O. , Wetter T. , Skonetzki S.
Published: March 2018

Objectives:
In order to implement clinical practice guidelines for the Department of Neonatology of the Heidelberg University Medical Center we developed a modular framework consisting of tools for authoring, browsing and executing encoded clinical practice guidelines (CPGs).

Methods:
Based upon a comprehensive analysis of literature, we set up requirements for guideline representation systems. Additionally, we analyzed further aspects such as the critical appraisal and known bridges and barriers for implementing CPGs. Thereafter we went through an evolutionary spiral model to develop a comprehensive ontology. Within this model each cycle focuses on a certain topic of management and implementation of CPGs.

Results:
In order to bring the resulting ontology into practice we developed a framework consisting of a tool for authoring, a server for web-based browsing, and an engine for the execution of certain elements of CPGs. Based upon this framework we encoded and implemented several CPGs in varying medical domains.

Conclusions:
This paper shall present a practical framework for both authors and implementers of CPGs. We have shown the fruitful combination of different knowledge representations such as narrative text and algorithm for implementing CPGs. Finally, we introduced a possible approach for the explicit adaptation of CPGs in order to provide institution-specific recommendations and to support sharing with other medical institutions.
Penalized Binary Regression for Gene Expression Profiling
Authors: Schimek Michae
Published: March 2018

Objectives:
A typical bioinformatics task in microarray analysis is the classification of biological samples into two alternative categories. A procedure is needed which, based on the expression levels measured, allows us to compute the probability that a new sample belongs to a certain class.

Methods:
For the purpose of classification the statistical approach of binary regression is considered. High-dimensionality and at the same time small sample sizes make it a challenging task. Standard logit or probit regression fails because of condition problems and poor predictive performance. The concepts of frequentist and of Bayesian penalization for binary regression are introduced. A Bayesian interpretation of the penalized log-likelihood is given. Finally the role of cross-validation for regularization and feature selection is discussed.

Results:
Penalization makes classical binary regression a suitable tool for microarray analysis. We illustrate penalized logit and Bayesian probit regression on a well-known data set and compare the obtained results, also with respect to published results from decision trees.

Conclusions:
The frequentist and the Bayesian penalization concept work equally well on the example data, however some method-specific differences can be made out. Moreover the Bayesian approach yields a quantification (posterior probabilities) of the bias due to the constraining assumptions.