Biomedical subjects

T M Ganey

Publications and source records attributed to T M Ganey.

At least 19 recordsLinked to original sources

PubMed2000

Does long-term compressive loading on the intervertebral disc cause degeneration?

STUDY DESIGN: Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs of dogs for up to 53 weeks. OBJECTIVE: To test the hypothesis that compressive forces applied to the intervertebral disc for a long period of time cause disc degeneration in vivo in a dog model. SUMMARY OF BACKGROUND DATA: It is a commonly held belief that high forces applied to the intervertebral disc, and to joints in general, play a role in causing degeneration. METHODS: Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs (L3/L4) of 12 dogs. After up to a year, the dogs were killed, and their lumbar spines were removed and radiographed. The L3/L4 disc and the controls (T13/L1 and L4/L5) were excised and examined for visible signs of degeneration. The discs then were assessed using immunohistochemical analysis and enzyme-linked immunosorbent assay. Disc chondrocytes also were assayed for apoptosis. RESULTS: No obvious signs of degeneration in the discs (L3/L4) that had been under compression for up to a year could be observed. There was no disc bulging, anular fissures, or disc space narrowing. Some changes were observed at the microscopic level, although no thickening of the endplate was apparent. The enzyme-linked immunosorbent assay analysis provided significant data for all three regions of the disc (nucleus, inner anulus, and outer anulus). When comparing the compressed disc (L3/L4) with either of the control discs (T13/L1 and L4/L5), in the compressed disc: 1) the nucleus contained less proteoglycan and more collagen I and II; 2) the inner anulus contained less proteoglycan and collagen I; and 3) the outer anulus contained more proteoglycan and less collagen I. The collagen II differences for the inner and outer anulus were not significant. CONCLUSION: Compression applied to the lumbar intervertebral discs of dogs for up to a year does not produce degeneration in any visible form. It does produce microscopic changes and numerical changes, however, in the amounts of proteoglycan and collagen in the nucleus, inner anulus, and outer anulus. The present results add no credence to the commonly held belief that high compressive forces play a causative role in disc degeneration.

Animals↗

PubMed2000

Coaxial portals for posterior ankle arthroscopy: An anatomic study with clinical correlation on 29 patients.

PURPOSE: The authors performed a cadaveric study on 10 ankles and retrospectively reviewed 29 arthroscopic synovectomies to determine the trajectory, minimal safe distances, and complications using a new approach for posterior ankle arthroscopy. TYPE OF STUDY: Anatomic study and case series. MATERIALS AND METHODS: A posterolateral portal was established immediately posterior to the peroneal tendon sheath. While staying within the posterior ankle capsule, an inside-out technique was then used to establish the posteromedial portal directly behind the medial malleolus adjacent to the posterior tibial tendon. The cadaveric ankles were frozen, sectioned, and photographed to measure the proximity of neurovascular structures to these coaxial portals. From 1988 to 1994, arthroscopic synovectomy was performed on 23 patients (29 ankles) with hemophilia using these modified portals. RESULTS: Results of the anatomic study showed that the posterior tibial nerve and posterior tibial artery were located a mean distance of 5.7 mm (SEM, 0.6 mm) and 6.4 mm (SEM, 0.7 mm) from the edge of the cannula, respectively. Neither penetration nor contact of nerve or vessel was observed at either posterior portal. In the 29 clinical cases, posterior capsular synovectomy was achieved arthroscopically with no detectable complications at an average 45-month follow-up. CONCLUSIONS: Our anatomic data show that the coaxial portals described here are essentially equidistant to the neurovascular structures compared with conventional portals. Our clinical results suggest that his technique for posteromedial and posterolateral portals is safe, effective, and reproducible.

Adolescent↗

PubMed2000

Morphologic and radiographic characterization of fibular dimelia.

Fibular dimelia accompanied by complete tibial agenesis is a rare developmental anomaly that has been reported in the anatomic and clinical literature as both a dimelia and a diplopodia. Previous reports have offered variable descriptions of structural aberration and possible modes of altered embryologic development. We present a clinical and radiographic history of the progressive development of this anomaly, and a detailed postsurgical dissection and histopathologic examination. The specific mirroring of the separate components in this case has not been previously reported, and suggests that a reestablishment of limb polarity may have occurred during embryogenesis. Our detailed morphologic investigation strongly suggests a central role for the mesenchymal precursor from which chondro-osseous morphology subsequently emerges, and the relevance to establishing muscular attachments.

Amputation, Surgical↗

PubMed1999

Mechanical comparison of plates used in the treatment of unstable subtrochanteric femur fractures.

OBJECTIVES: To determine the stiffness and strength characteristics of certain plate-composite femur models designed to simulate unstable subtrochanteric femur fractures (OTA 31-A2.3). DESIGN: Fifteen identical composite femora were osteotomized to produce like models of an unstable subtrochanteric femur fracture. The femora were fixed with either the Synthes 95 degree angled condylar blade plate, a 95 degree dynamic condylar screw plate (DCS), or a 135 degree dynamic compression hip screw (DHS). MAIN OUTCOME MEASUREMENTS: A materials testing machine was used to apply compression to the femoral head through an adapter plate. Stiffness values were calculated from the load-deformation curves obtained. RESULTS: The DHS-femur model was the stiffest (586 newtons/ millimeter), followed by the 95 degree DCS (404 newtons/millimeter) and the 95 degree condylar blade plate (260 newtons/ millimeter). The DHS also had the highest ultimate load-to-failure (4,877 newtons), followed by the 95 degree DCS (3,107 newtons) and the 95 degree condylar blade plate (2,272 newtons). All of these differences were statistically significant (p < 0.00001 ). CONCLUSIONS: Our findings suggest that the Synthes 95 degree DCS has greater stiffness and strength than the Synthes 95 degree condylar blade plate when tested in this model of an unstable subtrochanteric femur fracture. This model may not be completely appropriate for testing the 135 degree DHS because the hard plastic "cortex" of the model prevented cut-out of the screw.

Bone Plates↗

PubMed1998

The effect of compressive force applied to the intervertebral disc in vivo. A study of proteoglycans and collagen.

STUDY DESIGN: Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs of dogs for up to 27 weeks. OBJECTIVE: To test the hypothesis that a high compressive force applied over a period of time affects the production of proteoglycans and collagen by the intervertebral disc cells. SUMMARY OF BACKGROUND DATA: It is a commonly held belief that high forces applied to the intervertebral disc, and to joints in general, play a role in causing degeneration. METHODS: Pairs of stainless steel coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs (L1-L2 and L3-L4) of 16 dogs. Dogs were killed between 13 and 27 weeks after the springs were attached. The discs (L1-L2 and L3-L4) were excised and assessed using immunohistochemical analyses and enzyme-linked immunosorbent assay; T13-L1 and L4-L5 were used as controls. RESULTS: The main result relates to a group effect in the six dogs, assessed using enzyme-linked immunosorbent assay, that were generally at the highest values of force for the greatest number of weeks. For the nucleus, but not the anulus, Spearman rank correlations revealed a strong correlation between increases in force and force-weeks (force multiplied by number of weeks) and increases in collagen type I accompanied by decreases in proteoglycans, chondroitin sulfate, and collagen type II for both experimental discs (L1-L2 and L3-L4), as compared with corresponding values in the controls (T13-L1 and L4-L5). In other words, as either the force or the force-weeks increased, the effect on the nucleus became greater. CONCLUSION: A high compressive force applied to the disc over a period of time initiates changes in proteoglycans and collagen.

Aggrecans↗

PubMed1998

Guidelines to decortication in posterolateral spine fusion.

Despite the development of innovative approaches and the general success that has been achieved with spinal fusion, the rate of nonunion in some studies has been reported as high as 35%. Decortication has been shown to promote the fusion process and provides not only a rich source of vascular supply from the underlying cancellous bone, but also access to pluripotent stem cells within the marrow. Although the blood supply to the lumbar spine has been described, little attention has been paid to relevant areas of the spine most affected by decortication during the posterolateral fusion process. To assess these areas of the spine and attribute some potential importance to spinal fusion outcome, a perfusion study was designed to delineate the vascular anatomy involved in a decortication procedure. Cadaver spines were perfused with a radiopaque contrast material, fixed, decalcified, and cleared en bloc by the method of Spalteholz. Transverse, sagittal, and coronal slabs were made and the vascular supply was documented. The dominant intraosseous architecture of the vertebra reflected a cancellous bone structure, characterized by marrow and a sinusoidal blood distribution within a trabecular matrix. A contrasting architecture could be differentiated in the pars interarticularis that was more consistent with dense, cortical bone. Matrix from this region typified haversian lamellar bone and exhibited parallel osteons that contained a central vascular component. The relevance of this variance could have multiple implications, given the differences between cortical and cancellous bone in function, formation, healing, and remodeling. In posterolateral intertransverse process arthrodesis, the transverse processes and lateral facets are good areas to be decorticated, whereas the pars interarticularis is less attractive.

Aged↗

PubMed1997

The primary care physician's role in evaluating the pediatric amputee.

The clinician must have an understanding of the spectrum of potential problems that can occur in the pediatric patient with a limb deficiency. These various complications-osseous, nonosseous, infection, phantom limb phenomenon and pain, pre-existing conditions, and psychosocial-are discussed.

Amputation, Surgical↗

PubMed1997

Impingement after total hip arthroplasty related to prosthetic component selection and range of motion.

This study was designed to define the relationship between different combinations of prosthetic head diameters, neck lengths, and acetabular containment angles, and range of motion before component impingement. Three cadaveric pelves with attached lower limbs were mounted in their correct anatomic position. Acetabular and modular femoral stems were inserted into each of the six hips. For each combination of femoral head diameter, neck length, and acetabular liner overhang, the range of motion to impingement was measured in flexion, extension, abduction, adduction, external rotation, internal rotation, and internal rotation with 90 degrees hip flexion. These experiments suggest that the maximum range of motion before impingement can be attained by increasing the prosthetic head diameter and avoiding longer neck lengths with skirts. Acetabular liners with greater overhang decrease motion in all planes except flexion when the overhang is positioned posteriorly.

Arthroplasty, Replacement, Hip↗

PubMed1996

Metallic dissolution of a civil war bullet embedded in a sternum.

The contemporary trend of converting departments of anatomy into departments of cell biology has brought with it the task of examining archive collections and storage facilities to figure out how to best utilize the available space. During one such inspection at the University of Louisville School of Medicine, a human sternum containing a dull metal projectile was uncovered. The projectile was easy to characterize as a bullet that had been deeply embedded in the bone. Less clear, however, were the circumstances detailing how the bullet had become lodged in the sternum, or how long the sternum might have been in storage at the University of Louisville. Radiographs of the sternum revealed a halo of surrounding density that dissipated in intensity from the margins of the bullet. Our initial hypothesis was that lead had been leached from the bullet into the bone matrix. To better assess what in fact contributed to this density, the sternum and the bullet were analyzed by energy-dispersive spectroscopy (EDS) to determine their elemental composition. That the bullet was composed of lead and aluminum was not surprising, but the extent to which the presence and dissolution of the bullet had affected the composition of the bony sternum was not entirely expected. The contribution of metal ions from the bullet to the inorganic matrix of bone was most notable for aluminum but nearly negligible for lead. This finding confirmed that bone affinity for metals is dependent upon the metal and supports previous reports that have suggested that lead is released from bone as soluble blood product during bony remodeling, whereas aluminum results in a significant elevation of bone density.

Aluminum↗

PubMed1995

Postnatal development of the thoracic spine.

STUDY DESIGN: Forty-two thoracic spines ranging from neonate to 15 years of age were studied. OBJECTIVES: Postnatal development of the thoracic vertebrae and their component elements were cataloged. SUMMARY OF BACKGROUND DATA: This study was part of an ongoing series concerning the progressive morphologic development of the human postnatal skeleton. METHODS: The spines were studied morphologically and radiologically. RESULTS: Fusion of the thoracic spine neurocentral synchondroses occurs in a cranial to caudal direction in humans by 6 to 7 years of age. The transverse processes exhibit a progressive posterior and inferior angulation with age and moving down the thoracic spine. The facet joints angulate accordingly. The spinous processes elongate and increasingly angulate with age, especially in the mid-thoracic region. The relative contribution of the posterior elements, compared with the centrum, to the growth of the vertebral body progressively decreases moving down thoracic spine. CONCLUSION: This study demonstrated areas of anatomic change that undoubtedly play a role in normal and abnormal spine development.

Adolescent↗

PubMed1995

Basement membrane composition of cartilage canals during development and ossification of the epiphysis.

BACKGROUND: Cartilage canals are perichondral invaginations of blood vessels and connective tissue that are found within the epiphyses of most mammalian long bones. Functionally, they provide a means of transport of nutrients to the hyaline cartilage, a mechanism for removal of metabolic wastes, and a conduit for stem cells that are capable of initiating and sustaining ossification of the chondroepiphysis. Morphological and biomolecular changes of the chondroepiphyses appear to potentiate ossification within the chondroepiphyses of developing bones. METHODS: As both cell migration and vascular invasion are anchorage dependent processes, antibodies to laminin and Type IV collagen were used to assess compositional changes in the basement membrane of cartilage canals accompanying epiphyseal ossification. RESULTS: Differences in chronological appearance, as well as, in distribution between the two components were noted in the chondroepiphysis. Laminin was distributed throughout the connective tissue of cartilage canal at all stages of development, and not limited to an association with the vascular lumen. Type IV collagen was not present during the initial perichondral invagination. Although staining for Type IV collagen was later acquired, its distribution was restricted to a discontinuous rimming of the periphery of the canal, and a diffuse presence within the intra-canalicular mesenchyme. CONCLUSIONS: Concurrent with chondrocyte hypertrophy and mineralization of the hyaline matrix, rapid changes in both the morphology of the vessel and distribution of the antibodies were detected. In addition to the presence of laminin at the interface of the endothelium and the hyaline matrix, a wide distribution within the connective tissue components of the newly ossifying matrix of epiphyseal bone could be detected. Type IV collagen remained closely associated with the lumens of the intra-canalicular vessels throughout the transition. Following ossification of the secondary center, staining for Type IV collagen could then be detected in the bone-forming regions of transforming matrix as well, clearly delineating the individual vessels within the newly formed marrow spaces. This suggests that bone formation is intimately related to vessel staining for collagen type IV, and that acquired vessel competence is a facet of endochondral bone formation that results from provisional matrix changes. Furthermore, the data suggests that during bone formation under tension, basement membrane deposition can be demonstrated without an intermediary hyaline matrix hypertrophic chondrocyte phase. This data was interpreted to suggest that chondrocyte hypertrophy at the growth plate may be a reaction to vascular invasion, that in turn, stimulates adjacent chondrocyte proliferation.

Animals↗

PubMed1995

Assessment of bone formation during osteoneogenesis: a canine model.

Distraction osteoneogenesis, callotasis, has been demonstrated to be an effective means of lengthening long bones. A variation of Ilizarov's technique produces a transport disk from one cut surface of bone within a defect and advances the disk to the opposite surface to close the defect. This process, previously described by Costantino et al. (Arch Otolaryngol Head Neck Surg 1990; 116:535-45), demonstrated bone formation within the distraction site. The precise mechanism of bone formation has not yet been described for the mandible. Four conditioned beagles were studied, with one control dog maintained in neutral fixation and three dogs distracted at 0.25 mm every 8 hours. A two-cm defect was closed, and dogs were kept in fixation for 1 week after closure, after which they were killed. Three sites were evaluated: (1) the distraction seam, (2) the interface of the cortical and distracted bone, and (3) the cortexes at the closed defect. Each site was bisected, and one half was decalcified for immunohistochemical and hematoxylin and eosin pathologic evaluation. The vascular basement membrane was labeled for laminin and type IV collagen. Both of these substances demonstrate the differentiation of the vascular matrix component predisposing primary bone formation. Labels were intense at the distraction seam where intense angiogenesis occurred. No hyalin cartilage was observed at the distraction site, which indicates that the fixation was stable and that ossification occurred primarily without intermediate callous formation. This model demonstrated that osteoclasts within the canine model produce bone through primary bone formation within an angiogenic matrix rich in basement membrane laminin and type IV collagen. Likewise, bone is species specific in mineral composition for dog mandible. Understanding the formation and composition of distracted bone is essential for understanding application of this technique within the clinical setting.

Animals↗

PubMed1995

Fracture of a bipartite medial cuneiform synchondrosis.

We report the occurrence of a bipartition and occult growth plate fracture in the medial cuneiform of a 5-year, 11-month-old traumatic amputee. Initial radiographs of the foot taken in an oblique projection revealed what appeared to be an osseous fracture of the medial cuneiform. Histologic examination of the pathologic specimen showed that the radiolucent cleft separating the two foci of ossification was actually a hyaline synchondrosis (growth plate) functioning in the normal endochondral transformation of the bone. Histology also detailed a previously undetected fracture traversing the synchondrosis that was sustained during the accident. This unusual case demonstrates that radiographic discontinuity often does not correspond to anatomic discontinuity and should not be misdiagnosed as an osseous fracture. Yet, as with all growth plates of the chondro-osseous skeleton, occult injury to the growth mechanism should be suspected in instances of obvious trauma. Discriminating between normal development of the skeleton and skeletal pathology can be a challenge to the treating physician. Therefore, an awareness of possible anatomic variations will enhance diagnostic evaluations.

Child, Preschool↗

PubMed1994

Spontaneously occurring fractures of the spine in skeletally immature animals.

STUDY DESIGN: Twelve spontaneously occurring fractures of the spin in nine skeletally immature animals were investigated. OBJECTIVES: These fractures were analyzed radiographically, morphologically, and histologically. SUMMARY OF BACKGROUND DATA: The most commonly injured regions were the cervical and lumbar regions. Multiple-level fractures were noted in three specimens. METHODS: Morphologic and histologic examination invariably detected fractures in cases of spinal cord injury without radiographic abnormality. RESULTS: The end-plate physes and synchondroses were found to be the "weak links" for propagation of fractures. Radiographically benign-appearing ring apophyseal fractures were found histologically to propagate from the end-plate physis through the vertebral body via the contiguous neurocentral synchondroses. CONCLUSIONS: The observed morphologic and histologic fracture patterns should provide a better understanding of the probable comparable pathoanatomy of spine and spinal cord injuries in children.

Animals↗

PubMed1994

Meniscal ossification. I. Human.

Ossicles appearing in the medial menisci of three patients appeared to be post-traumatic in two and developmental in one. The histologic analysis in the two post-traumatic patients showed relatively normal bone and cartilage, but without the specific structural cartilaginous adaptations found in a naturally occurring large animal model. The third patient, with tibia vara and TAR (thrombocytopenia--absent radius) syndrome, developed the ossicle spontaneously. He is the youngest reported patient, to date, to develop this anatomic variation.

Adolescent↗

PubMed1994

Meniscal ossification. II. The normal pattern in the tiger knee.

Examination of knee menisci of Bengal tigers revealed ossicles within the cartilaginous anterior horn of each medial meniscus. This ossification was not evident in the neonatal animal, but was present in animals aged 20 months or older. The ossicle appeared prior to the completion of skeletal maturation at the knee, and was composed of normal remodeling trabecular bone. While most animals had a single, variably sized ossicle, multiple ossicles also occurred. The meniscal cartilage apposed to the femoral articulation exhibited a distinct columnar pattern in the region of the ossicle, in contrast to the non-columnar pattern throughout the bulk of the meniscus, including the ossicle side apposed to the tibial plateau. In this particular large mammalian species medial meniscal ossification appears to be a normal anatomical variation that progressively develops following birth, and may serve as a model for the phylogenetic (developmental) theory of etiology.

Aging↗

PubMed1994

Ossification and pseudoepiphysis formation in the "nonepiphyseal" end of bones of the hands and feet.

Metacarpals, metatarsals, and phalanges were studied to assess the developmental morphology of "secondary" ossification in the "nonepiphyseal" ends of these bones as well as the formation of the pseudoepiphysis as an epiphyseal ossification variant. Both direct ossification extension from the metaphysis into the epiphysis and pseudoepiphysis formation preceded, and continued to be more mature than, formation and expansion of the "classic" epiphyseal (secondary) ossification center at the opposite end of each specific bone. Direct metaphyseal to epiphyseal ossification usually started centrally and expanded hemispherically, replacing both physeal and epiphyseal cartilage simultaneously. In contrast, when remnants of "physis" were retained, while juxtaposed epiphyseal cartilage was replaced, a pseudoepiphysis formed. There were three basic patterns of pseudoepiphysis formation. First, a central osseous bridge extended from the metaphysis across the "physis" into the epiphysis and subsequently expanded to create a mushroom-like osseous structure. In the second pattern a peripheral osseous bridge formed, creating either an osseous ring or an eccentric bridge between the metaphysis and the epiphysis. In the third pattern, multiple bridging occurred. In each situation the associated remnant "physis" lacked typical cell columns and was incapable of significantly contributing to the postnatal longitudinal growth of the involved bone. Pseudoepiphyses were well formed by 4-5 years and coalesced with the rest of the bone months of years before skeletal maturation was attained at the opposite epiphyseal end, which ossified in the typical pattern (i.e., formation of a secondary center de novo completely within the cartilaginous epiphysis). This process may also affect the development and appearance of ossification within the longitudinal epiphyseal bracket ("delta phalanx").

Adolescent↗

PubMed1994

Asymmetric bifurcation of the extensor digitorum longus tendon in a case of congenital digitus minimus varus.

Congenital digitus minimus varus (overlapping of the fifth toe) is often bilateral and may result from an anatomic deformity of the extensor digitorum longus tendon. Although bifurcation of the tendinous slip to the fifth toe has been reported as an anatomical variant, in those patients affected with overlapping fifth toe, a pronounced asymmetry between the medial and lateral components may occur. Not only do the two slips to the fifth toe differ in girth, but the morphology of the separate tissues reflects a dissimilar level of organization. Surgical techniques for correction of secondary overlap should consider the possibility of altered gross and histologic anatomy of the extensor tendon when attempting to preserve function.

Child↗