Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Back”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed2000

Seat back and head restraint response during low-speed rear-end automobile collisions.

Automobile seat backs and head restraints play a key safety role during low-speed rear-end collisions, yet few studies have explored the effect of collision variables on seat response. In this study, the effects of vehicle speed change and seat belt use on dynamic seat back and head restraint response during low-speed rear-end automobile collisions were examined. Four human subjects were repeatedly exposed to vehicle-to-vehicle rear-end collisions with speed changes of 2, 4, 6 and 8 km/h. Seat back force and deflection, and head restraint force were measured. The point of application of the resultant force applied to the seat back and head restraint were determined. The magnitude and time of peak kinematic and kinetic response parameters were used in a two-way repeated-measures analysis of variance (ANOVA) for speed change and seat belt use. The results showed that 20 of the 24 seat back and head restraint response parameters varied with speed change and none of the parameters varied with seat belt use. Head restraint forces, seat back forces and seat back deflections increased approximately linearly with speed change, whereas time to peak response, direction and moment arm of the forces remained either constant or varied only slightly over the range of speed changes tested.

Acceleration↗
PubMedDate not supplied

Characteristics of pullout failure in conical and cylindrical pedicle screws after full insertion and back-out.

BACKGROUND CONTEXT: Biomechanical studies show that bone-mineral density, pedicle morphology, and screw thread area affect pedicle screw pullout failure. The current literature is based on studies of cylindrical pedicle screw designs. Conical screws have been introduced that may provide better "fit and fill" of the dorsal pedicle as well as improved resistance to screw bending failure. However, there is concern about loss of fixation if conical screws must be backed out after insertion. PURPOSE: To determine that conical screws have comparable initial stiffness and fixation strength compared with standard, cylindrical screws, and to assess whether conical screw fixation deteriorates when screws are backed out from full insertion. STUDY DESIGN/SETTING: This biomechanical analysis compared pullout strength of cylindrical and conical pedicle screw designs, using porcine lumbar vertebrae in a paired testing format. METHODS: Porcine lumbar vertebrae were instrumented with conical and cylindrical pedicle screws with the same thread pitch, area and contour, and an equivalent diameter at the pedicle isthmus, 1.2 cm distal to the hub. Axial pullout was performed at 1.0 mm/minute displacement. Pullout loads, work and stiffness were recorded at 0.02-second intervals. Conical versus cylindrical screws were tested using three paired control configurations: fully inserted, backed out 180 degrees and backed out 360 degrees. Fully inserted values were compared with each set of back-out values to determine relative loss of fixation strength. Screw pullout data were analyzed using a Student's t test. RESULTS: Pullout loads in these porcine specimens were comparable to data from healthy human vertebrae. Conical screws provided a 17% increase in the pullout strength compared with cylindrical screws (P<.10) and a 50% increase in initial stiffness (P<.05) at full insertion. There was no loss in pullout strength, stiffness or work to failure when conical or cylindrical screws were backed out 180 or 360 degrees from full insertion. CONCLUSIONS: Conical screws offer improved initial fixation strength compared with cylindrical screws of the same size and thread design. Our results suggest that appropriately designed conical screws can be backed out 180 to 360 degrees for intraoperative adjustment without loss of pullout strength, stiffness or work to failure. Intraoperative adjustments of these specific conical screws less than 360 degrees should not affect initial fixation strength. These results may not hold true for screws with a smaller thread area or larger minor diameter.

Animals↗
PubMed2006

Working memory deficits in multiple sclerosis: comparison between the n-back task and the Paced Auditory Serial Addition Test.

Working memory (WM) deficits are common in multiple sclerosis (MS). The Paced Auditory Serial Addition Test (PASAT) is used frequently to measure WM in clinical settings. The n-back paradigm is used often in experimental studies of WM. One unique component of the n-back task is that it provides a measure of reaction time (RT), an additional behavioral index of processing speed and task difficulty. Despite the use of both tasks to measure WM, their common variance has not been documented. We tested 32 MS patients and 20 controls; performance measures were obtained for both tasks. Compared with controls, MS patients generally had poorer performance on both the PASAT and n-back task. MS patients also had slower RTs on the n-back than controls and showed more slowing than controls as a function of WM load. Correlational analyses showed a high correspondence between performance measures on the PASAT and n-back. Principal components analysis pointed to a common feature of the PASAT, n-back, and specific other neuropsychological measures, that is, processing speed. Although the PASAT and n-back were shown to have a significant amount of shared variance, each test has specific advantages and disadvantages for use in clinical populations.

Acoustic Stimulation↗
PubMed1999

Comparing the rates and the activation parameters for the forward reaction between the triplet state of zinc cytochrome c and cupriplastocyanin and the back reaction between the zinc cytochrome c cation radical and cuproplastocyanin.

This is a comparative study of the photoinduced (so-called forward) electron-transfer reaction 3Zncyt/pc(II) --> Zncyt+/pc(I), between the triplet state of zinc cytochrome c (3Zncyt) and cupriplastocyanin [pc(II)], and the thermal (so-called back) electron-transfer reaction Zncyt+/pc(I) --> Zncyt/pc(II), between the cation (radical) of zinc cytochrome c (Zncyt+) and cuproplastocyanin [pc(I)], which follows it. Both reactions occur between associated (docked) reactants, and the respective unimolecular rate constants are kF and kB. Our previous studies showed that the forward reaction is gated by a rearrangement of the diprotein complex. Now we examine the back reaction and complare the two. We study the effects of temperature (in the range 273.3-302.9 K) and viscosity (in the range 1.00-17.4 cP) on the rate constants and determine enthalpies (DeltaH), entropies (DeltaS), and free energies (DeltaG) of activation. We compare wild-type spinach plastocyanin, the single mutants Tyr83Leu and Glu59Lys, and the double mutant Glu59Lys/Glu60Gln. The rate constant kB for wild-type spinach plastocyanin and its mutants markedly depends on viscosity, an indication that the back reaction is also gated. The activation parameters DeltaH and DeltaS show that the forward and back reactions have similar mechanisms, involving a rearrangement of the diprotein complex from the initial binding configuration to the reactive configuration. The rearrangements of the complexes 3Zncyt/pc(II) and Zncyt+/pc(I) that gate their respective reactions are similar but not identical. Since the back reaction of all plastocyanin variants is faster than the forward reaction, the difference in free energy between the docking and the reactive configuration is smaller for the back reaction than for the forward reaction. This difference is explained by the change in the electrostatic potential on the plastocyanin surface as Cu(II) is reduced to Cu(I). It is the smaller DeltaH that makes DeltaG smaller for the back reaction than for the forward reaction.

Amino Acid Substitution↗
PubMed2003

Backing up behaviors in teams: the role of personality and legitimacy of need.

In this article, the authors developed several hypotheses regarding both the main and interactive effects of 2 types of team inputs on backing up behaviors in teams: (a) team composition characteristics in terms of the personality of the members of the team and (b) team task characteristics in terms of the extent to which the nature of the task is one that legitimately calls for some members of the team to back up other members of the team. Results from a study of 71 4-person teams performing a computerized tactical decision-making task suggest that the legitimacy of the need for back up has an important main effect on the extent to which team members provide assistance to and receive assistance from each other. In addition, the legitimacy of the need for back up also has important interactive effects with both the personality of the back up recipient and the personality of the back up providers on backing up behaviors in teams.

Cooperative Behavior↗
PubMed2003

Safety and efficacy of percutaneous neuromodulation therapy in the management of subacute radiating low back pain.

OBJECTIVE: Percutaneous neuromodulation therapy (PNT) is a new minimally invasive, office-based treatment for low back pain in which electrical stimulation is delivered to the paraspinal peripheral nerves. The purpose of this study was to determine the safety, tolerability, and clinical efficacy of PNT in a population of patients with subacute low back pain with radiation to the lower extremity. DESIGN: Open label prospective clinical trial. SETTING: Multi-center outpatient setting. PARTICIPANTS: We enrolled 83 patients who had radiating low back pain for 4 weeks to 6 months with a pain intensity of at least 4 on a visual analog scale of 0-10. INTERVENTIONS: Subjects were treated with PNT 1 to 2 times per week for at least 4 weeks. Based on clinical response patients were treated up to an additional 8 weeks. MAIN OUTCOME MEASURES: We recorded baseline visual analog scale (VAS) scores of radiating pain, low back pain, physical activity, and sleep, as well as the Oswestry Disability Questionnaire. Follow-up assessments were performed at each session, and at 5 and 12 weeks. Patients benefiting from treatments at 12 weeks were followed-up at 6 months. RESULTS: Fifty-nine patients completed the study protocol. Mean VAS scores improved as follows: leg/buttock pain decreased by 37% to 4.0 +/- 2.6 from a baseline of 6.6 +/- 1.7 (P < 0.001); low back pain decreased by 26% to 3.9 +/- 2.4 from a baseline of 5.5 +/- 2.2 (P < 0.001); activity levels improved by 38% to 3.6 +/- 2.2 from a baseline of 6.0 +/- 2.2 (P < 0.001); and sleep improved by 27% to 3.1 +/- 2.5 from a baseline of 4.8 +/- 3.0 (P < 0.001). The Oswestry Low Back Pain Disability scores improved by 24% to 32 +/- 16 from a baseline of 43 +/- 15 (P < 0.001). Pain relief was sustained over a 3-month observation period. CONCLUSION: For many patients with subacute radiating low back pain, PNT significantly reduced pain and self-rated disability, and improved sleep quality and activity level. PNT is safe and generally well tolerated.

Journal Article↗
PubMed2000

Optimum seat pan and back-rest parameters for a comfortable tractor seat.

An experimental set up was fabricated to measure the pressure distribution on the seat pan and back-rest of a tractor seat. Experiments were conducted with four different seat pans having radius of curvatures of 60, 75, 90 and infinity cm, four back-rests with radius of curvatures of 30, 60, 90 and infinitity cm, and three back-rest inclinations of 0 degrees , 5 degrees and 10 degrees on representative Indian tractor operators. The subjective assessment of perceived comfort at the seat-operator interface was also recorded. Experiments were conducted in a randomized block design and the data obtained were analysed using suitable computer packages. Results indicate that all the parameters, namely seat pan, back-rest profile curvatures and the back-rest angle of inclination, affect the pressure distribution. It is concluded that a seat pan with radius of curvature 75 cm, back-rest with radius of curvature 30 cm and back-rest inclination of 10 degrees are the most suitable parameters for Indian tractor operators.

Adolescent↗
PubMed2003

Effect of a redesigned two-wheeled container for refuse collecting on mechanical loading of low back and shoulders.

The objective of this study was to compare the mechanical and perceived workload when working with a redesigned two-wheeled container and working with a standard two-wheeled container for refuse collecting. The three changes in the design of the container were a displacement of the position of the centre of mass in the direction of the axis of the wheels, a slight increase in the height of the handle and a slight increase in the horizontal distance between the handle and the wheel-axis, and an increase in the diameter of the wheels. The volume of the container remained 0.240 m3. Nine refuse collectors performed some of their most frequent daily activities with both types of containers in the laboratory. Kinematics and exerted hand forces were assessed as input for detailed 3D biomechanical models of the low back and shoulder to estimate net moments at the low back and shoulders, compressive forces at the low back and contact forces at the glenohumeral joint. Also, the refuse collectors rated the ease of handling the two-wheeled containers on a five point scale. The use of the redesigned container resulted in a decrease of the exerted hand forces of 27%, decreases in the net moments at the low back and shoulders of 8% and 20%, respectively, and a decrease of 32% of the contact force at the glenohumeral joint when compared to the standard container. However, pulling an empty redesigned container on to the pavement resulted in an increase of the shoulder moment of more than 100%. No differences between container types were found for the compressive forces at the low back. Pushing and pulling with the redesigned container was rated as easier than pushing and pulling with the standard container. No differences in subjective ratings were found for the tasks of turning the container or pulling an empty container onto the pavement. It is concluded that, provided that empty containers are placed back onto the pavement as infrequently as possible, the introduction of the redesigned container could result in a reduction of the low back and shoulder load for refuse collectors.

Adult↗
PubMed1995

Can back supports relieve the load on the lumbar spine for employees engaged in industrial operations?

In recent years, there has been an increased use of back supports in US industry to reduce the frequency and concomitant costs of lower-back disorders. The obvious question is, 'Can back supports relieve the load on the lumbar spine for employees engaged in industrial operations?'. This paper is directed towards answering this question because there have been mixed conclusions in the literature reporting on the efficacy of back supports. The literature concerning the biomechanical, physiological and psychophysical effects of back supports on the human spine has been reviewed as well as the use of back supports to control injury in the workplace. A critical assessment of the findings reported by various investigators has been made together with a discussion of the mechanisms used by the trunk muscles to provide extrinsic stability to the spine. It is hypothesized that the extrinsic stability of the spine is manifested through more than one mechanism. These mechanisms may act simultaneously or sequentially to stabilize the trunk. Finally, the ergonomics of back supports as a corporate policy are discussed.

Humans↗
PubMed1994

Long-term gonadotrophin-releasing hormone agonist therapy: the evolving issue of steroidal 'add-back' paradigms.

The introduction of steroid 'add-back' regimens draws on the recognition that several clinical entities targeted for treatment with gonadotrophin-releasing hormone agonist (GnRHa) are not '6-month diseases'. Included under this heading are individuals suffering from symptomatic endometriosis (not desires of pregnancy), uterine fibroids (ineligible or disinterested in definitive surgical therapy), ovarian hyperandrogenism, premenstrual syndrome, menopausal transition, or dysfunctional uterine bleeding. A 6-month course of therapy with a GnRHa does not adversely affect lipoprotein economy and therefore presumably the corresponding cardiovascular risk. A 6-month course of GnRHa therapy appears to be associated with a substantial decrease (of up to 8.2%) in lumbar bone density, a phenomenon which may not be entirely reversible 6 months after discontinuation of therapy. In principle, steroid 'add-back' therapy should diminish some or all of the side-effects associated with GnRHa therapy, may provide a medical treatment option for patients representing a high surgical risk, and may delay surgical intervention if desired. On the other hand, a steroid 'add-back' therapy may delay tissue diagnosis, be associated with a substantial cost as well as with the need for parenteral route of administration. Norethindrone-only (but not medroxyprogesterone acetate-only) 'add-back' regimens have proved promising in the context of endometriosis. Non-concurrent oestrogen/progestin 'add-back' regimens proved promising in the context of uterine fibroids. Substantial additional studies would have to be carried out to validate the utility of steroid 'add-back' regimens. Special emphasis will have to be placed on the evaluation of long-term utility with an eye towards assessing clinical efficacy, impact on lipoprotein economy, impact on bone density, impact on urogenital tissues, and impact on the hot flush. The concurrent or non-concurrent use of non-steroid 'add-back' regimens will also most likely constitute a major component of future studies.

Bone Density↗
PubMed2000

A randomized comparison of all-polyethylene and metal-backed tibial components.

Clinical failures of all-polyethylene tibial components in total knee arthroplasty generally have been failures of design, not materials. The current study was designed to compare a modern congruent all-polyethylene tibial component with a metal-backed tibial component with the same articular design and geometry. All patients older than 60 years of age requiring total knee arthroplasty were randomized prospectively to receive either a cemented posterior cruciate ligament-retaining all-polyethylene component or a metal-backed tibial component with identical articular surfaces. All patients received identical cemented femoral and all-polyethylene patellar implants. The mean age of the patients was 69 years, and the mean American Society of Anesthesiology score was 3. The diagnosis was osteoarthritis in 92% of this population. Three hundred twenty-four total knee arthroplasties in 296 patients were performed; 213 joints (111 all-polyethylene tibias and 102 metal-backed tibias) with a minimum of 3 years followup (mean, 49 months) are reported. The preoperative Knee Society knee score in the group of patients who received an all-polyethylene tibial component was 38 points, improving to 84 points at latest followup, whereas in the group of patients who received a metal-backed tibial component, the score improved from 35 to 85 points. Functional scores increased from preoperative values of 56 to 74 points in the patients who received all-polyethylene tibial components, and 57 to 72 points in the patients who received metal-backed tibial components. Range of motion measured at latest followup averaged 106 degrees in patients who received an all-polyethylene tibial component and 107 degrees in the patients who received a metal-backed component, and postoperative tibiofemoral alignment averaged 6 degrees valgus for both groups. There were 13 reoperations for instability, patellofemoral problems, or deep infection, but none for aseptic loosening or wear in either group. These differences were not statistically significant, nor were any measures of patient satisfaction or clinical outcome between the two groups in this period. Total knee arthroplasty with a well-designed, contemporary congruent all-polyethylene tibial component functions equivalently to its metal-backed tibial counterpart at 3- to 5-year followup in this patient population, and is less costly ($675).

Aged↗
PubMed2001

Outcome of metal-backed cementless patellar components: the effect of implant design.

Failure of metal-backed cementless patellar components frequently has been observed clinically. To determine the effect of component design on clinical outcome, the authors reviewed the results of total knee arthroplasty with metal-backed patellar components of two different designs. The results of 168 total knee arthroplasties (Miller-Galante) with dome-shaped metal-backed patellar components and 93 total knee arthroplasties Miller-Galante II with modified dome-shaped metal-backed patellar components were reviewed. Kaplan-Meier survivorship was determined for both groups. Revision for patellar wear or failure was done or recommended in 36 Miller-Galante total knee arthroplasties. The cumulative survival rates at 3, 5, 7, and 9 years postoperatively were 99%, 92%, 81%, and 73%, respectively for this group. In contrast, only three of 93 Miller-Galante II patellar components required revision. Catastrophic patellar component failure, typically seen with the Miller-Galante metal-backed patellar components, was not observed with the Miller-Galante II components. Cumulative survival of the Miller-Galante II patella at 3, 5, 7, and 9 years postoperatively was 100%, 100%, 98.7%, and 93.2% respectively. The results of the current study show a dramatic reduction in metal-backed component failure by design changes incorporated into the modified dome-shaped Miller-Galante II patellar component and highlights the importance of design on the survival of cementless metal-backed patellar components.

Adult↗
PubMed2005

The long-term results of a metal-backed mobile bearing patella.

UNLABELLED: Enthusiasm for metal-backed patella has waned because of the high incidence of complications. Considering that perhaps all metal-backed patellae may not be the same, 256 primary consecutive metal-backed mobile bearing TKAs done between May 1985 and January 1989 were retrospectively reviewed to evaluate the results of a unique mobile bearing metal-backed patella. There were four complications (1.6%). Three patella were revised for polyethylene complications and one well-functioning component was removed at the time of revision of the tibial polyethylene to facilitate range of motion and wound closure. No patella was revised for loosening, subluxation, or dislocation. Our results show that all metal-backed patella are not the same and that compared with the high incidence of failure of fixed bearing metal-backed patellae, the use of the anatomic mobile bearing metal-backed patella can produce excellent, durable long-term clinical and radiographic results with a low incidence (1.6%) of complications. Life table survivorship using revision for any reason as the end point was 97% (95% confidence interval, 93%-100%) at a maximum of 19 years. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2003

Use of the reverse latissimus muscle flap for closure of complex back wounds in patients with spinal cord injury.

STUDY DESIGN: Our study was designed as a retrospective review of spinal cord patients with complex back wounds in whom the reverse latissimus muscle flap was used for closure. OBJECTIVES: The objective was to evaluate the efficacy and outcomes in these patients. SUMMARY OF BACKGROUND DATA: Earlier publications give only anecdotal reports on the treatment of complex back wounds in patients with spinal cord syndrome. The data so far available do not allow any comparison of the various methods used. METHODS: Fourteen patients with congenital or acquired spinal cord syndrome and with an average age of 31.2 years (range 12-76 years) had complex back wounds in the thoracic and lumbar regions, which were closed in each case with a reverse latissimus dorsi muscle flap. The patients had deep wound infection and wound dehiscence following spondylodesis (n = 6), dead space and wound dehiscence following laminectomy (n = 6), or decubitus ulcers over the spine (n = 2). The spinal cord syndrome was chronic in nine patients and acute in five. The pre- and postoperative treatment and the actual operation were all done in a spinal cord injury center. In nine patients, the back wound was closed in a primary procedure, and in five, a split-thickness skin graft was used to close it. In 11 patients, primary wound healing was achieved with no complications after closure, whereas in 3 patients, complications with the back wound or the donor site led to disturbances of wound healing lasting up to 25 weeks. Five operations had to be performed specifically because of these complications. RESULTS: At follow-up 27.4 months (mean; range 8-114 months) after the operation, all back wounds were closed, free of irritation, and completely healed. The patients did not report any handicaps in everyday life, loss of strength in the upper extremities, or functional restrictions. One patient had a deep vein thrombosis in one leg. No further complications linked with the spinal cord syndrome were ascertained. The instrumentation used during the spondylodesis operation was left in place in four cases. The spondylodesis became solidly fused in each of these cases. CONCLUSION: Use of the reverse latissimus muscle flap is a reliable method of closing complex back wounds in patients with spinal cord syndrome. Should there be complications in the area of the flap, secondary wound healing can be achieved by wound debridement and closure of the wound by means of split-thickness skin grafting. There is no loss of function in the upper extremities. The complications typically seen in spinal cord patients can be avoided when the treatment is carried out in the conditions that obtain in a specialized spinal cord injury center.

Adolescent↗
PubMed2006

Risk of pediatric back-over injuries in residential driveways by vehicle type.

OBJECTIVE: Research suggests that children experience driveway back-over injuries at a significant rate and the severity of the resulting injuries differ by type of vehicle. Yet, no US study attempted to quantify "back-over risk" for classes of vehicles because of the difficulties with determining exposure. Using vehicle registration information, we set out to estimate the relative risk of driveway back-over injuries to children by type of vehicle. METHODS: Driveway back-over events were identified from state police reports and medical records from the state level 1 pediatric trauma center and compared with vehicle registration information to estimate injury incidence for 4 classes of vehicles (passenger cars, trucks, sport utility vehicles, and minivans) over 6 years in the state of Utah. RESULTS: Reported driveway back-over injuries represent an incidence of 7.09 per 100,000 children (<10 years old) per year. Overall, passenger cars account for 1.62 injuries per 100,000 registered vehicles. Compared with passenger cars, children were 53% more likely to be injured by a truck (P = 0.01) and 2.4 times more likely to be injured by a minivan (P < 0.001). Among children transported to a trauma center, admission (P = 0.01) and need for surgery (P = 0.03) were greater among children backed over by trucks, sport utility vehicles, and minivans compared with passenger cars. CONCLUSIONS: Findings suggest that when assessing driveway back-over injuries, larger high-profile vehicles are associated with a higher incidence and severity of injuries when compared with injuries resulting from passenger cars.

Accidents, Home↗
PubMed2006

Intrapartum analgesia and its association with post-partum back pain and headache in nulliparous women.

BACKGROUND: The effect of intrapartum analgesia on post-partum maternal back and neck pain, headache and migraine, is uncertain. AIMS: To determine if nulliparous women having epidural analgesia during labour have a similar incidence of the above-mentioned post-partum symptoms compared with women managed using other forms of pain relief. METHODS: Secondary analysis of cohort data from a randomised trial in which nulliparous women intending to deliver vaginally were randomised to either epidural analgesia (EPI) or continuous midwifery support (CMS) at admission for delivery. Because of high cross-over rates, groups were initially defined by the randomised treatment allocation and the actual treatment received (CMS-CMS n = 185, EPI-CMS n = 117, EPI-EPI n = 376 and CMS-EPI n = 314). Univariate analysis showed no difference between groups, so final analysis was based on the actual treatment received. RESULTS: Six hundred and ninety women received epidural analgesia (EPIDURAL) and 302 received other methods of pain relief including CMS. Back pain was common before, during and after pregnancy, and risk factors for post-partum back pain at six months were back pain prior to pregnancy or at two months post-partum. Epidural analgesia, mode of delivery, spontaneous or induced labour, birthweight and back pain during pregnancy had no significant relationship with post-partum back pain at six months. Headache was significantly more common in the EPIDURAL group during pregnancy and at two months post-partum, but not at six months. Migraine was not associated with intrapartum analgesia. CONCLUSIONS: This analysis supports previous research suggesting that epidural analgesia is not a significant risk factor for persisting post-partum back pain, headache or migraine.

Adult↗
PubMedDate not supplied

Mothers' perceptions of the quality of their infants' back transfer.

OBJECTIVE: To describe mothers' experiences with back transfer of their infants from a neonatal intensive-care unit (NICU) to a community hospital (CH). DESIGN: Descriptive correlational study. PARTICIPANTS: One hundred forty-three mothers whose infants were back transferred from regional NICUs to 1 of 20 Level I or Level II CHs. MAIN OUTCOME MEASURES: Quality of back transfer was measured by the NICU/CH Transfer Quality Scale developed by the investigators. Overall level of stress related to back transfer was also measured. RESULTS: More positive experiences with the NICU component of back transfer were related to fewer perceived differences in physician practice between NICUs and CH settings and fewer infant problems after transfer (R2 = 8.1%, p = .007). More positive experiences with the CH component of back transfer were related to fewer perceived differences in nursing and medical practices between settings; fewer infant problems after transfer; and more sources of pretransfer preparation (R2 = 33.4%, p < .0001). Lower levels of overall stress associated with transfer were related to fewer infant problems after transfer and greater lengths of stay in the NICU (R2 = 8.8%, p = .01). CONCLUSION: Results support the need for consistency of care and coordinated approaches to back transfer.

Adolescent↗
PubMed2001

Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse.

Speed related changes in trunk mechanics have not yet been investigated, although high-speed training is currently used in the horse. To evaluate the effects of speed on back kinematics and trunk muscles activity, 4 saddle horses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5 to 6 m/s. The 3-dimensional (3-D) trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was simultaneously obtained from the longissimus dorsi (LD) and rectus abdominis (RA) muscles using surface electrodes. Ten consecutive strides were analysed for each horse at each of the 5 velocity steps. Electromyographic and kinematic data were time-standardised to the duration of the stride cycle and compared using an analysis of variance. The back extended during the first part of each diagonal stance phase when the RA was active and the back flexed during the second part of each diagonal stance phase when the LD was active. The onset and end of muscle activity came earlier in the stride cycle and muscle activity intensity increased when speed increased. The amplitude of vertical movement of the trunk and the maximal angles of flexion decreased with increasing speed, whereas the extension angles remained unchanged. This resulted in a decreased range of back flexion-extension. This study confirms that the primary role of trunk muscles is to control the stiffness of the back rather than to induce movements. Understanding the effects of speed on the back of healthy horses is a prerequisite for the prevention and treatment of back pathology.

Animals↗