Outcomes and Lessons Learned from the Tribal Veterans Representative Program: A Model for System Engagement.

American Indian and Alaska Native Veterans are more rural than Veterans of any other race or ethnicity and face significant barriers to accessing care. Since 2001, the Tribal Veterans Representative (TVR) Program, a partnership between the U.S. Department of Veterans Affairs (VA) and tribal nations, has trained liaisons from tribal communities to facilitate access to VA benefits and services. We delineate the TVR program model alongside supporting data. We reviewed TVR training materials and program evaluations to identify components of the program essential for increasing access to VA services and benefits. We then report a quantitative assessment of benefits attained in one tribal community. The TVR model is characterized by the exchange of two sets of knowledge and resources-'institutional' and 'community'-during a co-sponsored educational program aiming to train community liaisons about the institution. The institution leads the program's content; the community's traditions inform its process. Following the program, liaisons use support networks comprising trainers, trainees and local organizations to teach other community members to access health care and benefits. In the evaluation community, one liaison has facilitated access for hundreds of Veterans, with financial compensation exceeding $400,000 annually. The TVR program has begun to demonstrate its utility for other rural populations, though further formal evaluation is recommended. Compared with similar models to increase rural populations' access to health care and benefits, the long-term support networks from the TVR model may be most useful when the institution must build trust and engage with the target population.

A computational model of cardiac fibroblast signaling predicts context-dependent drivers of myofibroblast differentiation.

Cardiac fibroblasts support heart function, and aberrant fibroblast signaling can lead to fibrosis and cardiac dysfunction. Yet how signaling molecules drive myofibroblast differentiation and fibrosis in the complex signaling environment of cardiac injury remains unclear. We developed a large-scale computational model of cardiac fibroblast signaling in order to identify regulators of fibrosis under diverse signaling contexts. The model network integrates 10 signaling pathways, including 91 nodes and 134 reactions, and it correctly predicted 80% of independent previous experiments. The model predicted key fibrotic signaling regulators (e.g. reactive oxygen species, tissue growth factor ß (TGFß) receptor), whose function varied depending on the extracellular environment. We characterized how network structure relates to function, identified functional modules, and predicted cross-talk between TGFß and mechanical signaling, which was validated experimentally in adult cardiac fibroblasts. This study provides a systems framework for predicting key regulators of fibroblast signaling across diverse signaling contexts.

Tribal Veterans Representative (TVR) training program: the effect of community outreach workers on American Indian and Alaska Native Veterans access to and utilization of the Veterans Health Administration.

American Indians and Alaska Natives serve at the highest rate of any US race or ethnic group, yet are the most underserved population of Veterans and do not take advantage of the Department of Veterans Affairs (VA) benefits and services. Barriers to seeking care include stigma, especially for mental health issues; distance to care; and lack of awareness of benefits and services they are entitled to receive. In response to this underutilization of the VA, an innovative program--the Tribal Veterans Representative (TVR) program--was developed within the VA to work with American Indians and Alaska Natives in rural and remote areas. The TVR goes through extensive training every year; is a volunteer, a Veteran and tribal community member who seeks out unenrolled Native Veterans, provides them with information on VA health care services and benefits, and assists them with enrollment paperwork. Being from the community they serve, these outreach workers are able to develop relationships and build rapport and trust with fellow Veterans. In place for over a decade in Montana, this program has enrolled a countless number of Veterans, benefiting not only the individual, but their family and the community as well. Also resulting from this program, are the implementation of Telemental Health Clinics treating Veterans with PTSD, a transportation program helping Veterans get to and from distant VA facilities, a Veteran Resource Center, and a Veteran Tribal Clinic. This program has successfully trained over 800 TVRs, expanded to other parts of the country and into remote areas of Alaska.

Altered phenotypic gene expression of 10T1/2 mesenchymal cells in nonuniformly stretched PEGDA hydrogels.

Disease-related phenotype modulation of many cell types has been shown to be closely related to mechanical loading conditions; for example, vascular smooth muscle cell (SMC) phenotype shift from a mature, contractile state to a proliferative, synthetic state contributes to the formation of neointimal tissue during atherosclerosis and restenosis development and is related to SMC mechanical loading in vivo. The majority of past in vitro cell-stretching experiments have employed simplistic (uniform, uniaxial or biaxial) stretching environments to elucidate mechanobiological pathways involved in phenotypic shifts. However, the in vivo mechanics of the vascular wall consists of highly nonuniform stretch. Here we subjected 10T1/2 murine mesenchymal cells (an SMC precursor) to two- and three-dimensional nonuniform stretch environments. After 24 h of stretch, cells on an elastomeric membrane demonstrated varied proliferation [assessed by 5-bromo-2'-deoxyuridine (BrdU) incorporation] depending on location upon the membrane, with maximal proliferation occurring in a region of high, uniaxial stretch. Cells subjected to a nonuniform stretching regimen within three-dimensional polyethylene glycol diacrylate (PEGDA) hydrogel constructs demonstrated marked changes in mRNA expression of several phenotype-related proteins, indicating a sort of "hybrid" phenotype with contractile and synthetic markers being both upregulated and downregulated. Furthermore, expression levels of mRNAs were significantly different between various locations within the stretched gel. With the proliferation results, these data exhibit the capability of nonuniform stretching devices to induce heterogeneous cell responses, potentially indicative of spatial distributions of disease-related behaviors in vivo.

Reaching rural communities with culturally appropriate care: a model for adapting remote monitoring to American Indian veterans with posttraumatic stress disorder.

OBJECTIVE: Providing specialized healthcare to rural communities can be extremely difficult, and consequently many health organizations are turning to the use of telehealth technologies for care delivery. One such technology, remote monitoring, has been successfully implemented with patients suffering from chronic and other medical conditions. A drawback, however, is that remote monitoring devices are programmed to reach a broad audience, and consequently the content may not be suitable for all patients-especially those who are not a part of the dominant culture. SUBJECTS AND METHODS: This report provides a model for adapting remote monitoring to specific populations who are undergoing care for posttraumatic stress disorder. Adaptation changes focus on (1) information gathering, (2) process and dialogue changes, (3) testing, and (4) patient and administrative feedback. Data for such modifications were gathered through a series of community meetings, patient interviews, and provider feedback. A case example highlights the successful implementation of the adaptation model for a rural American Indian Veteran population. RESULTS: Patients showed high acceptability of both the programmatic and cultural adaptations. Feasibility of the program also appeared positive, with most patients reporting that the readability of the program was appropriate, the dialogue duration was not burdensome, and technical problems were rare. CONCLUSIONS: Remote monitoring provides the ability to be modified for use with certain subpopulations. Procedural recommendations in this report highlight special considerations for working with American Indians living on or near reservation areas, although the model can be broadly adapted to several groups.

Review of American Indian veteran telemental health.

Rural American Indian veterans have unique healthcare needs and face numerous barriers to accessing healthcare services. Over the past decade, the Department of Veterans Affairs in conjunction with the University of Colorado Denver has turned to the promising field of telemental health to develop a series of videoconferencing-based clinics to reach this vulnerable population and improve mental healthcare services. The ongoing development, implementation, and expansion of these clinics have been assessed as part of a program improvement. The outcomes of these assessments have been documented in a series of published articles, controlled studies, program and case reports, and model descriptions. This article summarizes a decade of experience with the American Indian Telemental Health Clinics, the clinic model, and the literature arising from these clinics and presents lessons learned while establishing, maintaining, and evaluating these clinics. The ability to tailor the clinics to individual sites and cultures and to provide various services has been critical to the operation of the clinics. Culturally specific care through culturally knowledgeable providers, onsite tribal outreach workers, and collaboration with community services has proven essential in operating the clinics, as well as building rapport, trust, and engagement with the target patient population. It is hoped that the lessons learned and practices presented here can not only assist others working to improve the care for rural Native veterans but also serve as a model in the use of telemental health services for improving care and access to rural veteran and non-veteran populations.

Rural American Indian and Alaska Native veterans' telemental health: A model of culturally centered care.

American Indian and Alaska Native (AI/AN) veterans living in rural areas have unique health care needs and face numerous barriers to accessing health care services. Among these needs is a disproportionate prevalence of posttraumatic stress disorder and other mental illnesses. Since 2001, 14 rural communities have partnered with the U.S. Department of Veterans Affairs and the Centers for American Indian and Alaska Native Health at the University of Colorado Anschutz Medical Campus to extend telemental health clinics to American Indian veterans. Administrative and, to some extent, clinical considerations of these clinics have been reviewed previously. This paper describes a model of care, evolved over a 14-year period, that weaves together evidence-based Western treatment, traditional Native healing, and rural Native communities into 4 main components: mental health care, technology, care coordination, and cultural facilitation. We delineate improvements to care made by addressing barriers such as system transference, provider-patient trust, and videoconferencing. Similarly, the discussion notes ways that the care model leverages strengths within Native communities, such as social cohesion and spirituality. Future steps include selection of appropriate performance indicators for systematic evaluation. The identification of key constructs of this care model will facilitate comparisons with other models of care in underserved populations with chronic and complex health conditions, and eventually advance the state of care for our warriors. (PsycINFO Database Record

Improved assessment of lumbar vertebral body strength using supine lateral dual-energy x-ray absorptiometry.

Clinical and biomechanical investigations indicate that assessment of vertebral body bone mineral density (BMD) by anteroposterior dual-energy x-ray absorptiometry (DXA) is a useful index of vertebral body strength and fracture risk in osteoporosis. However, inclusion of non-force-bearing and small-force-bearing mineralized structures, such as the posterior elements and aortic calcifications, in the measurement of anterior BMD obscures the assessment of vertebral body mass by this technique. Indeed, such interference is particularly severe in the presence of posterior element degeneration or previous spinal surgery. Recent anatomic studies illustrate that the lateral view provides unobstructed visualization of the L3, L4, and possibly L2 vertebral bodies, suggesting that supine lateral BMD may more accurately assess vertebral body fracture risk. We evaluated this hypothesis in a blinded using human cadaver spines to compare the value of supine lateral and anteroposterior BMD in assessing vertebral body fracture force, average compressive stress, maximum stored strain energy, and strain at failure. Both measures of BMD significantly correlate with these biomechanical measures. However, statistical comparison of the methods using multiple and stepwise regression reveals that supine lateral BMD provides a better assessment of the vertebral body fracture properties than anteroposterior BMD. The enhanced predictive value of supine lateral BMD occurs because of the variable contribution of posterior element mineral to the anteroposterior BMD measurement. Evaluation to test the utility of supine lateral BMD for the assessment of fracture risk and a fracture threshold in patients with osteoporosis is therefore recommended.

Wind and orientation of migrating birds: a review.

Migratory flights are strongly affected by wind, and birds have developed many adaptations to cope with wind effects. By day, overland migrants at high altitudes may often allow crosswinds to drift their tracks laterally from the preferred heading. In contrast, many birds at low altitude adjust their headings to compensate for drift, and may overcompensate to allow for previous drift. The relative motion of landscape features is probably used to sense drift, at least by day. By night, some overland migrants compensate fully for drift, but others do not. Compensation may be more common where there are prominent topographic features. Over the sea, compensation is rarely if ever total; wave patterns may allow partial compensation. Other adaptations can include reduction of drift by flying at times and/or altitudes without strong crosswinds. Some birds recognize the need to change course to allow for previous wind displacement, and reorient at least roughly toward the original route or destination. Some juveniles en route to previously unvisited wintering grounds seem to have this ability, but corroboration is needed. Such reorientation may not require a true navigation ability. However, some birds have unexplained abilities to sense the wind while aloft.

Surgical correction of lumbar kyphotic deformity: posterior reduction "eggshell" osteotomy.

OBJECT: Progressive kyphotic deformity of the lumbar or thoracolumbar spine may lead to back pain, cosmetic deformity, and risk of neurological compromise. The authors describe a series of patients in whom they performed a single-stage, posterior reduction ("eggshell") osteotomy procedure to improve sagittal contour by creating lordosis within a single vertebral body. METHODS: From 1995 to 1997 the authors performed 12 osteotomy procedures in 11 patients with thoracolumbar or lumbar kyphosis. Seven patients presented with iatrogenic deformity, three with deformity secondary to traumatic injury, and one patient with ankylosing spondylitis. Their mean age at time of surgery was 46.6 years (range 23-78 years). All patients suffered from back pain and were unable to stand upright, but in only one patient were neurological findings demonstrated. The mean preoperative deformity was -26 degrees (range -90 to 0 degrees). At 6-month follow-up examination the mean sagittal contour measured 17.5 degrees (range - 17 to 44 degrees), indicating that the mean surgical correction was 40.1 degrees (range 25 to 58 degrees). All patients reported decreased back pain at follow up, and none required narcotic analgesic medication. Complications included a dense paresis that developed immediately postoperatively in a patient who was found to have residual dural compression, which was corrected by emergency decompressive surgery. One elderly patient suffered a perioperative cerebrovascular accident, and three patients suffered neurapraxia with transient muscle weakness of the quadriceps. There was one case of a dural tear. There were no deaths, and prolonged intensive care stays were not required. CONCLUSIONS: Single-level posterior reduction osteotomy provides excellent sagittal correction of kyphotic deformity in the lumbar region, with a risk of cauda equina and root and plexus compromise due to the extensive neural exposure.

Severe open subtalar dislocations. Long-term results.

Fifteen adolescents and adults were assessed an average of eighteen years after a type-III open subtalar dislocation. There were ten lateral and five medial dislocations. Associated injuries included ten injuries of the tibial nerve, seven of which were complicated by causalgia; five ruptures of the posterior tibial tendon; five lacerations of the posterior tibial artery; twelve articular fractures involving the subtalar joint; three articular fractures of the talonavicular joint; three fractures of the talar dome; and three malleolar fractures. Osteonecrosis of the body of the talus was found in five of the fifteen patients. It was treated with a triple arthrodesis in all five patients, one of whom had a subsequent conversion to a pantalar arthrodesis. Subtalar arthrodesis was done, because of post-traumatic osteoarthrosis, in two other patients. On functional assessment at the long-term follow-up examination, all patients reported some pain in the ankle, nine had difficulty climbing stairs, fourteen had difficulty walking on uneven surfaces, and eleven wore modified shoes. The patients who had had a tarsal arthrodesis returned to their pre-injury occupation or to a less strenuous job. Four patients who had persistent causalgia did not return to work. We concluded that open subtalar dislocation is a distinctly severe injury and that only fair functional and poor anatomical results can be expected in most patients.

Experimental impact injury to the cervical spine: relating motion of the head and the mechanism of injury.

The purpose of this study was to analyze, with use of an impact model, the relationships among motion of the head, local deformations of the cervical spine, and the mechanisms of injury; the model consisted of the head and neck of a cadaver. Traditionally, the mechanisms of injury to the cervical spine have been associated with flexion and extension motions of the head and neck. However, the classification of the mechanisms is not always in agreement with the patient's account of the injury or with lacerations and contusions of the scalp, which indicate the site of the impact of the head. Eleven specimens were dropped in an inverted posture with the head and neck in an anatomically neutral position. Forces, moments, and accelerations were recorded, and the impacts were imaged at 1000 frames per second. The velocity at the time of impact was on the order of 3.2 meters per second. The angle and the padding of the impact surface varied. Observable motion of the head did not correspond to the mechanism of the injury to the cervical spine. Injury occurred 2.2 to 18.8 milliseconds after impact and before noticeable motion of the head. However, the classification of the mechanism of the injuries was descriptive of the local deformations of the cervical spine at the time of the injury. Accordingly, it is a useful tool in describing the local mechanism of injury. Buckling of the cervical spine, involving extension between the third and sixth cervical vertebrae and flexion between the seventh and eight cervical vertebrae, was observed. Other, more complex, buckling deformations were also seen, suggesting that the deformations that occur during impact are so complex that they can give rise to a number of different mechanisms of injury.

Dynamic responses of the head and cervical spine to axial impact loading.

This study explores the inertial effects of the head and torso on cervical spine dynamics with the specific goal of determining whether the head mass can provide a constraining cervical spine end condition. The hypothesis was tested using a low friction impact surface and a pocketing foam impact surface. Impact orientation was also varied. Tests were conducted on whole unembalmed heads and cervical spines using a drop track system to produce impact velocities on the order of 3.2 m s-1. Data for the head impact forces and the reactions at T1 were recorded and the tests were also imaged at 1000 frames s-1. Injuries occurred 2-19 ms following head impact and prior to significant head motion. Average compressive load a failure was 1727 +/- 387 N. Decoupling was observed between the head and T1. Cervical spine loading due to head rebound constituted up to 54 +/- 16% of the total axial neck load for padded impacts and up to 38 +/- 30% of the total axial neck load for rigid impacts. Dynamic buckling was also observed; including first-order modes and transient higher-order modes which shifted the structure from a primarily compressive mode of deformation to various bending modes. These experiments demonstrate that in the absence of head pocketing, the head mass can provide sufficient constraint to cause cervical spine injury. The results also show that cervical spinal injury dynamics are complex, and that a large sample size of experimentally produced injuries will be necessary to develop comprehensive neck injury models and criteria.

Combined single stage anterior and posterior osteotomy for correction of iatrogenic lumbar kyphosis.

Fifty-four patients were treated by a standardized single stage anterior opening wedge and a posterior closing extension wedge osteotomy for back pain associated with postoperative loss of lumbar lordosis (iatrogenic flat back syndrome). Presenting complaints were fatigue, pain and a stooped posture. Etiological factors were, in descending order of frequency, distraction instrumentation with the lower end at the L5 or S1 vertebra, thoracolumbar junction kyphosis greater than 15 degrees, especially if associated with a hypokyphotic thoracic spine, and degenerative changes above and below a previous fusion. Kostuik-Harrington instrumentation was used anteriorly for the opening wedge and Dwyer cables and screws together with a midline plate were used posteriorly for the closing extension osteotomy. Malunion occurred in three patients, one requiring recorrection. Pain relief occurred in 48 (90%). Neurological complications occurred in two patients, one with permanent deficient. Follow-up averaged 4 years. Average preosteotomy lordosis L1-S1 was 21.5 degrees and was restored to 49 degrees (equal to the lordosis before the initial surgery) for an average correction of 29 degrees, (range 24 degrees to 63 degrees). Prevention of this complication can be accomplished by maintaining normal lordosis at the time of initial surgery.

The effects of padded surfaces on the risk for cervical spine injury.

STUDY DESIGN: This is an in vitro study comparing cervical spine injuries produced in rigid head impacts and in padded head impacts. OBJECTIVES: To test the hypothesis that deformable impact surfaces pose a greater risk for cervical spine injury than rigid surfaces using a cadaver-based model that includes the effects of the head and torso masses. SUMMARY OF BACKGROUND DATA: It is widely assumed that energy-absorbing devices that protect the head from injury also reduce the risk for neck injury. However, this has not been demonstrated in any experimental or epidemiologic study. On the contrary, some studies have shown that padded surfaces have no effect on neck injury risk, and others have suggested that they can increase risk. METHODS: Experiments were performed on 18 cadaveric cervical spines to test 6 combinations of impact angle and impact surface padding. The impact surface was oriented at -15 degrees (posterior impact), 0 degree (vertex impact), or +15 degrees (anterior impact). The impact surface was either a 3-mm sheet of lubricated Teflon or 5 cm of polyurethane foam. RESULTS: Impacts onto padded surfaces produced significantly larger neck impulses (P = 0.00023) and a significantly greater frequency of cervical spine injuries than rigid impacts (P = 0.0375). The impact angle was also correlated with injury risk (P < 0.00001). CONCLUSIONS: These experiments suggest that highly deformable, padded contact surfaces should be used carefully in environments where there is the risk for cervical spine injury. The results also suggest that the orientation of the head, neck, and torso relative to the impact surface is of equal if not greater importance in neck injury risk.

A biomechanical, radiologic, and clinical comparison of outcome after multilevel cervical laminectomy or laminoplasty in the rabbit.

STUDY DESIGN: A rabbit model was used to compare clinical outcome, radiographic changes, and biomechanical flexibility after cervical laminectomy and open-door laminoplasty. OBJECTIVE: This study tested the hypothesis that radiographic changes and biomechanical flexibility could explain the differences in clinical outcome after cervical laminectomy and laminoplasty. SUMMARY OF BACKGROUND DATA: Although multilevel cervical laminoplasty is thought to have advantages over cervical laminectomy, clinical outcome studies have been contradictory, and no experimental study has examined the possible mechanisms for the differences after healing. METHODS: Twenty-four New Zealand White rabbits were randomized into four groups: normal, sham, C3-C6 wide laminectomy, and C3-C6 open-door laminoplasty. Clinical, radiographic, and biomechanical data were collected and compared up to 3 months after surgery. RESULTS: Laminectomy had a statistically significant poorer clinical outcome when compared with laminoplasty after 3 months of healing. Radiologic analysis showed statistically significant angular deformity in the laminectomy group compared with laminoplasty and control groups at 3 months. In contrast, biomechanical measures of flexibility, neutral zone, and range of motion showed only small differences between any of the groups at any time. CONCLUSIONS: The presence of deformity, and not a change in flexibility, is responsible for the differences in clinical outcome observed after laminectomy compared with laminoplasty in this model.

The cervical facet capsule and its role in whiplash injury: a biomechanical investigation.

STUDY DESIGN: Cervical facet capsular strains were determined during bending and at failure in the human cadaver. OBJECTIVE: To determine the effect of an axial pretorque on facet capsular strains and estimate the risk for subcatastrophic capsular injury during normal bending motions. SUMMARY OF BACKGROUND DATA: Epidemiologic and clinical studies have identified the facet capsule as a potential site of injury and prerotation as a risk factor for whiplash injury. Unfortunately, biomechanical data on the cervical facet capsule and its role in whiplash injury are not available. METHODS: Cervical spine motion segments were tested in a pure-moment test frame and the full-field strains determined throughout the facet capsule. Motion segments were tested with and without a pretorque in pure bending. The isolated facet was then elongated to failure. Maximum principal strains during bending were compared with failure strains, by paired t test. RESULTS: Statistically significant increases in principal capsular strains during flexion-extension loading were observed when a pretorque was applied. All measured strains during bending were significantly less than strains at catastrophic joint failure. The same was true for subcatastrophic ligament failure strains, except in the presence of a pretorque. CONCLUSIONS: Pretorque of the head and neck increases facet capsular strains, supporting its role in the whiplash mechanism. Although the facet capsule does not appear to be at risk for gross injury during normal bending motions, a small portion of the population may be at risk for subcatastrophic injury.

The role of imaging and in situ biomechanical testing in assessing pedicle screw pull-out strength.

STUDY DESIGN: This study determined the predictive ability of quantitative computed tomography, dual energy x-ray absorptiometry, pedicular geometry, and mechanical testing in assessing the strength of pedicle screw fixation in an in vitro mechanical test of intra-pedicular screw fixation in the human cadaveric lumbar spine. OBJECTIVE: To test several hypotheses regarding the relative predictive value of densitometry, pedicular geometry, and mechanical testing in describing pedicle screw pull-out. SUMMARY OF BACKGROUND DATA: Previous investigations have suggested that mechanical testing, geometry, and densitometry, determined by quantitative computed tomography or dual energy x-ray absorptiometry, predict the strength of the screw-bone system. However, no study has compared the relative predictive value of these techniques. METHODS: Forty-nine pedicle screw cyclic-combined flexion-extension moment-axial pull-out tests were performed on human cadaveric lumbar vertebrae. The predictive ability of quantitative computed tomography, dual energy x-ray absorptiometry, insertional torque, in situ stiffness, and pedicular geometry was assessed using multiple regression. RESULTS: Several variables correlated to force at failure. However, multiple regression analysis showed that bone mineral density of the pedicle determined by quantitative computed tomography, insertional torque, and in situ stiffness when used in combination resulted in the strongest prediction of pull-out force. No other measures provided additional predictive ability in the presence of these measures. CONCLUSIONS: Pedicle density determined by quantitative computed tomography when used with insertional torque and in situ stiffness provides the strongest predictive ability of screw pull-out. Geometric measures of the pedicle and density determined by dual energy x-ray absorptiometry do not provide additional predictive ability in the presence of these measures.

Strength and stability of posterior lumbar interbody fusion. Comparison of titanium fiber mesh implant and tricortical bone graft.

STUDY DESIGN: A paired comparison was done of the bending flexibility and compression strength of tricortical bone graft and titanium fiber mesh implants in a human cadaver model of posterior lumbar interbody fusion. OBJECTIVES: To test the hypothesis that a titanium fiber mesh implant and a tricortical bone graft provide adequate and equal mechanical strength and stability in posterior lumbar interbody fusion constructs. SUMMARY OF BACKGROUND DATA: Although studies of posterior lumbar interbody fusion constructs have been performed, the authors are unaware of any study in which the strength and stability of a titanium fiber mesh implant are compared with those of tricortical bone graft for posterior lumbar interbody fusion in the human cadaver lumbar spine. METHODS: Changes in neutral zone and range of motion were measured in a bending flexibility test before and after placement of posterior lumbar interbody fusion constructs. Tricortical bone graft and titanium fiber mesh implant construct stability than were compared in a paired analysis. The constructs than were loaded to failure to evaluate construct strength as a function of graft material and bone mineral density. RESULTS: The posterior lumbar interbody fusion procedure produced statistically significant decreases in neutral zone when compared with the intact spine. No statistically significant differences in neutral zone, range of motion, or strength were detected between the two implants. Construct strength correlated strongly with bone mineral density. CONCLUSIONS: Posterior lumbar interbody fusion procedures result in equal or improved acute stability for titanium fiber mesh implants and tricortical bone graft implants when used without additional posterior stabilization.

Metastatic melanoma to the spine. Demographics, risk factors, and prognosis in 114 patients.

STUDY DESIGN: One-hundred-fourteen patients with metastatic melanoma of the spine were retrospectively reviewed. OBJECTIVE: The goal was to define the demographics, risk factors, and prognosis for this population. SUMMARY OF BACKGROUND DATA: The incidence of melanoma is increasing faster than any other cancer. Therefore, orthopedic and neurologic surgeons will be increasingly confronted by patients with spinal metastases from melanoma. However, the demographics, risk factors, and prognosis remain unclear. METHODS: From 7010 consecutive patients with melanoma, 114 were identified with clinically or radiographically evident spinal metastases. A comparison was made between these patients and the remainder of the population with melanoma seen at our institution using contingency table analysis with statistical significance determined by a chi-squared test. Survival data were represented by Kaplan-Meier curves, and log-rank testing was used for statistical comparisons. RESULTS: Risk factors associated with the development of these metastases included primary lesions that were ulcerated, deeper than 0.76 mm, or of Clark level II, or located on the trunk or mucosal surfaces. The median survival time for all patients was 86 days, but this was reduced in patients with more than one metastatic site in addition to the spine. CONCLUSION: The prognosis for most patients with spinal metastases from melanoma is dismal. However, patients with metastatic disease limited to the spine and one other organ may survive for a relatively prolonged time and may be candidates for surgical intervention directed toward symptomatic relief.