Truss implant technology™ for interbody fusion in spinal degenerative disorders: profile of advanced structural design, mechanobiologic and performance characteristics.

Introduction: Interbody fusion devices are customarily used in fusion of the anterior spinal column for treatment of degenerative disc disease. Their traditional role is to reestablish and maintain intervertebral disc height, contain bone graft and provide mechanical support for the spine while osseointegration takes place. Utilizing the principles of mechanobiology, a unique biokinetic interbody fusion device has been developed that employs an advanced structural design to facilitate and actively participate in the fusion consolidation process.Areas covered: This article profiles and characterizes 4WEB Medical's Truss Implant Technology™ which includes a range of 3D-printed titanium spinal interbody implants and non-spinal implants whose design is based on truss structures enabled by advances in additive manufacturing. Four main areas of the implant design and functionality are detailed: bio-architecture, mechanobiologic underpinnings, bioactive surface features, and subsidence resistance. Pre-clinical and clinical examples are provided to describe and specify the bioactive roles and contributions of each design feature.Expert opinion: The distinct and unique combination of features incorporated within the truss cage design results in a biokinetic implant that actively participates in the bone healing cascade and fusion process.

Strains in trussed spine interbody fusion implants are modulated by load and design.

Titanium cages with 3-D printed trussed open-space architectures may provide an opportunity to deliver targeted mechanical behavior in spine interbody fusion devices. The ability to control mechanical strain, at levels known to stimulate an osteogenic response, to the fusion site could lead to development of optimized therapeutic implants that improve clinical outcomes. In this study, cages of varying design (1.00 mm or 0.75 mm diameter struts) were mechanically characterized and compared for multiple compressive load magnitudes in order to determine what impact certain design variables had on localized strain. Each cage was instrumented with small fiducial sphere markers (88 total) at each strut vertex of the truss structure, which comprised of 260 individual struts. Cages were subjected to a 50 N control, 1000 N, or 2000 N compressive load between contoured loading platens in a simulated vertebral fusion condition, during which the cages were imaged using high-resolution micro-CT. The cage was analyzed as a mechanical truss structure, with each strut defined as the connection of two vertex fiducials. The deformation and strain of each strut was determined from 50 N control to 1000 N or 2000 N load by tracking the change in distance between each fiducial marker. As in a truss system, the number of struts in tension (positive strain) and compression (negative strain) were roughly equal, with increased loads resulting in a widened distribution (SD) compared with that at 50 N tare load indicating increased strain magnitudes. Strain distribution increased from 1000 N (+156 ± 415 µÎµ) to 2000 N (+180 ± 605 µÎµ) in 1.00 mm cages, which was similar to 0.75 mm cages (+132 ± 622 µÎµ) at 1000 N load. Strain amplitudes increased 42%, from 346µÎµ at 1000 N to 492µÎµ at 2000 N, for 1.00 mm cages. At 1000 N, strain amplitude in 0.75 mm cages (481µÎµ) was higher by 39% than that in 1.00 mm cages. These amplitudes corresponded to the mechanobiological range of bone homeostasis+formation, with 63 ± 2% (p < .05 vs other groups), 72 ± 3%, and 73 ± 1% of struts within that range for 1.00 mm at 1000 N, 1.00 mm at 2000 N, and 0.75 mm at 1000 N, respectively. The effective compressive modulus for both cage designs was also dependent on strut diameter, with modulus decreasing from 12.1 ± 2.3 GPa (1.25 mm) to 9.2 ± 7.5 GPa (1.00 mm) and 3.8 ± 0.6 GPa (0.75 mm). This study extended past micro-scale mechanical characterization of trussed cages to compare the effects of design on cage mechanical behavior at moderate (1000 N) and strenuous (2000 N) load levels. The findings suggest that future cage designs may be modulated to target desired mechanical strain regimes at physiological loads.

Ex vivo loading of trussed implants for spine fusion induces heterogeneous strains consistent with homeostatic bone mechanobiology.

A truss structure was recently introduced as an interbody fusion cage. As a truss system, some of the connected elements may be in a state of compression and others in tension. This study aimed to quantify both the mean and variance of strut strains in such an implant when loaded in a simulated fusion condition with vertebral body or contoured plastic loading platens ex vivo. Cages were each instrumented with 78 fiducial spheres, loaded between platens (vertebral body or contoured plastic), imaged using high resolution micro-CT, and analyzed for deformation and strain of each of the 221 struts. With repeated loading of a cage by vertebral platens, the distribution (variance, indicated by SD) of strut strains widened from 50N control (4±114µÎµ, mean±SD) to 1000N (-23±273µÎµ) and 2000N (-48±414µÎµ), and between 1000N and 2000N. With similar loading of multiple cages, the strain distribution at 2000N (23±389µÎµ) increased from 50N control. With repeated loading by contoured plastic platens, induced strains at 2000N had a distribution similar to that induced by vertebral platens (84±426µÎµ). In all studies, cages exhibited increases in strut strain amplitude when loaded from 50N to 1000N or 2000N. Correspondingly, at 2000N, 59-64% of struts exhibited strain amplitudes consistent with mechanobiologically-regulated bone homeostasis. At 2000N, vertically-oriented struts exhibited deformation of -2.87±2.04µm and strain of -199±133µÎµ, indicating overall cage compression. Thus, using an ex vivo 3-D experimental biomechanical analysis method, a truss implant can have strains induced by physiological loading that are heterogeneous and of amplitudes consistent with mechanobiological bone homeostasis.

Children's understanding of illness: students' assessments.

The purpose of this study was to examine the perceptions of graduate students in the fields of nursing, social work, child life, and counseling education regarding children's understanding of illness concepts. Students were assessed as to their knowledge of children's perceptions of illness as described from a Piagetian developmental viewpoint. Eighty-five graduate students from a southern university in the fields of nursing, social work, child development/child life, and counseling categorized statements made by children regarding their understanding of illness concepts. A data-gathering instrument, developed by Perrin & Perrin (1983), was used to assess the graduate students' ability to assign a developmental age to children's responses to illness-concept questions. Additionally, the students were evaluated on their knowledge of how children perceive illness identification, causality, prevention, treatment, and use of medication. The students correctly categorized by age, children's statements regarding illness concepts only 38% of the time and correctly identified knowledge statements 50% of the time. No remarkable differences were found among the areas of specialization. Without a knowledge base of developmental theories that can be applied directly to clinical practice, nurses are at a disadvantage when working with children and their families. A better understanding of children's communication needs can ultimately lead to improved coping abilities on the part of the child and appropriate interventions on the part of the nurse. The relatively low number of correct responses suggests a need for additional training opportunities that would incorporate cognitive developmental theory into clinical practice for nurses and other health care professionals who plan to work with children.

Impact of a chronic illness in childhood: siblings' perceptions.

This project investigated siblings' perceptions of family disruption when a brother or sister had cystic fibrosis (CF) or asthma. Data were gathered by phone interviews and questionnaires. Phone interviews were conducted with siblings of chronically ill children and employed open-ended questions focusing on the impact of the illness on the sibling and the family unit. Along with the interview, siblings also completed a separate self-esteem measure. Assessments of family functioning and demographic variables were obtained through parental questionnaires. Only the sibling interview data are addressed in this article. Fifteen families from the two illness groups participated. There were 6 male and 9 female respondents, with a mean age of 10.1 years. The average age of the well sibling was slightly older than the average age of the chronically ill child. For siblings of both disease groups, positive outcomes included strengthening some family relationships, achieving more personal independence, and experiencing satisfaction in seeing improvement in the ill child. Negative outcomes included worrying about the brother's or sister's illness, being jealous of the attention paid to the ill child, and the restriction of family events. Appropriate family interventions are suggested, as well as feedback as to the efficacy of phone interviews with school-age children.

Nurses, children, and play.

A child's play is recognized as a useful tool for nurses in the diagnostic process of making judgments about a hospitalized child's compliance with medical procedures, adjustment to the hospital environment, degree of pain, and level of psychosocial functioning. However, the knowledge base that is required to effectively help a pediatric patient "play" in a therapeutic mode appears to be extremely limited for most nurses and is rarely addressed in a substantive manner in nursing education. Educational programs must be willing to incorporate a "developmentally appropriate, culturally sensitive, and family-centered approach" using clinical experiences and professional role models in their nursing curricula. The end product should be nurses who are competent in a much wider range of medical technological and psychosocial issues than has been necessary in the past. In short, nurses must learn to play.

The aftereffects of a hostage situation on children's behavior.

The effects of the trauma on the behavior of elementary-school children who had been held hostage or been closely involved with the hostage situation were investigated, as also were the effects on the lives of their families. Specific types of negative behavior exhibited by the children were identified by teachers and parents, and were found to be linked to the length of time for which the children had been held hostage.

Perception of body image in children with burns, five years after burn injury.

Burn injuries and subsequent disfigurement may place children at high risk for psychologic dysfunction. If medical professionals are to aid the child in achieving psychologic resolution and acceptance of the injury, they must be aware of the stage of body-image perception that the child is experiencing. This study was designed to determine differences in body image between children with burns and children without burns through the use of human figure drawings. The experimental group consisted of 32 children with burns, aged 5 to 15 years, studied at approximately 5 years after burn injury. The control group consisted of 32 children without burns, aged 6 to 15 years. Subjects in the burn group were matched to control subjects by age and sex. There were no significant differences in body image in relation to any of the demographic measures except age. Age was inversely related to body image both in patients with burns and in control subjects.

Evaluation of social problem-solving abilities in rural home health visitors and visiting nurses.

A number of studies have shown the value of using home health visitors and visiting nurses in intervention outreach programs designed to provide pre- and postnatal care for low-income women. The purpose of this study was to compare the abilities of a selected sample of professionally trained nurses and nonprofessionally trained home health visitors to suggest and prioritize solutions to a medical dilemma. Data were gathered by the use of a Practical Solutions Test and a Ranking Solutions Procedure. The subjects for the study were 77 females residing in rural counties in West Alabama. The four study groups were comprised of: (a) trained home visitors with 0 to 6 months of experience, (b) trained home visitors with more than 6 months of experience, (c) professionally trained nurses, and, (d) a control group of women with no training or experience. Data were analyzed using one-way analysis of variance (ANOVA). The findings suggest that all of the trained groups were able to generate more solutions to a typical client medical dilemma than could the control group: F(3.76) = 11.79; p = .0001. Faced with the same medical dilemma, the nursing group was more likely to suggest medical options over socioemotional solutions than were the home visitors: chi 2(3.76) = 9.41; p = .02. The nurses also prioritized the solutions differently by ranking them in a different sequence.

Pediatric family home visitors: effectiveness in problem solving.

A number of studies have shown the value of using home health visitors in intervention outreach programs for low-income families. This study was designed to examine the relationship between home visitors' and nurses' training/home visiting experience and their decision-making ability as determined by the Defining Issues Test (DIT). The subjects were 36 home visitors, 13 visiting nurses, and 28 controls. A difference was found between the home visitors' and nurses' training/experience levels and group scores on the DIT, F(3, 75) = 3.13, p = 0.03. The nurses were better able to make decisions based on issues of fairness and justice than were the home visitors or the controls. The findings suggest the advisability of providing educational opportunities for home visitors to improve decision-making skills.

Children's adjustment to the hospital: a rural/urban comparison.

This paper presents the findings of an investigation to determine whether or not there is a difference in the degree of psychological upset of rural and urban children during hospitalization. The subjects in the study were 70 children between the ages of 4 and 17 years who participated in the Child Life Program during hospitalization at Children's Hospital in Birmingham, Alabama. The anxiety levels of the children were evaluated by using three instruments: a 13-item, self-report test of fears; a 64-item observation checklist of negative behaviors; and a 4-item anxiety rating scale. The results revealed that on specific measures rural children exhibited a statistically significantly greater degree of psychological upset during hospitalization than urban children. Implications of these results in determining procedures to reduce anxiety of children during hospitalization are briefly considered.

Storytelling: a measure of anxiety in hospitalized children.

This study investigates the use of storytelling as a method of measuring children's anxiety during hospitalization. Sixty-seven hospitalized children were asked to create stories about pictures they were shown. The stories were categorized as negative or positive in tone and, hence, the children were categorized as anxious or not anxious. Children who told negative stories displayed significantly more negative behaviors and showed significantly higher anxiety levels and poorer adjustment to hospitalization as measured by observational methods. The most anxious children were male, black, and rural. Implications for practitioners who work with children in medical settings are discussed.

Children's health care: brief report. Nature experiences for hospitalized children.

Numerous projects conducted in various settings have supported the thesis that nature activities aid in the development of self-concept, self-confidence, and level of achievement. The nature activities described in this article were designed to cultivate the hospitalized children a sense of wonder about their world and to involve them in sensory experiences that would aid them in adjusting to their hospital experiences. As a unit, these experiments provide a comprehensive approach to therapy for the hospitalized child and add a positive dimension to the child life program.