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PubMed1998

Intestinal rotational abnormalities in polysplenia and asplenia syndromes.

OBJECTIVE: To review the anomalies of intestinal rotation occurring in association with asplenia (right isomerism) and polysplenia (left isomerism) syndromes. MATERIALS AND METHODS: A retrospective study was performed of 27 children with asplenia (21) or polysplenia (6) identified from the cardiology and radiology databases from 1988 to 1996 and in whom an upper gastrointestinal barium study had been performed. The intestinal rotation was determined by reviewing the barium meal and could be divided into four groups: (1) normal rotation, (2) incomplete rotation or nonrotation, (3) reversed rotation and (4) reversed incomplete rotation or nonrotation. Surgical correlation was obtained at laparotomy in 17 patients. RESULTS: Of the 27 children studied, 3 (11 %) had normal rotation; incomplete rotation or nonrotation occurred in 5 (19 %), and 2 in this group developed midgut volvulus; 5 (19 %) had reversed rotation; 14 (52 %) had reversed incomplete rotation or nonrotation. CONCLUSION: Asplenia and polysplenia are frequently associated with intestinal malrotation, and a barium study is recommended in all of these children, as many will be at risk of midgut volvulus.

Abnormalities, Multiple↗
PubMed2004

Serotonergic influence on the potentiation of D-amphetamine and apomorphine-induced rotational behavior by the alpha2-adrenoceptor antagonist 2-methoxy idazoxan in hemiparkinsonian rats.

The alpha(2)-adrenoceptor antagonists potentiate both ipsilateral and contralateral rotations induced by amphetamine and apomorphine respectively in hemiparkinsonian rats. The present study investigated the role of serotonergic transmission in this potentiation in unilaterally 6-hydroxydopamine nigral lesioned rats. D-amphetamine (0.5 mg/kg, i.p.) produced ipsilateral rotations, which were decreased by the dopamine receptor antagonist haloperidol (0.2 mg/kg, i.p.) and the alpha(1)-receptor antagonist prazosin (1 mg/kg, i.p.). The selective alpha(2)-antagonist 2-methoxy idazoxan (0.2 mg/kg, i.p.) potentiated the amphetamine-induced ipsilateral rotations, that were attenuated by haloperidol and prazosin. The selective serotonin re-uptake inhibitor citalopram (10 mg/kg, i.p.) and selective serotonin synthesis inhibitor p-chlorophenylalanine (150 mg/kg, i.p., 3 days) decreased and increased the observed potentiation respectively. Apomorphine (0.2 mg/kg, s.c.) produced contralateral rotations, which were decreased by haloperidol but not by prazosin. 2-methoxy idazoxan potentiated these rotations which were attenuated by haloperidol but not by prazosin. Citalopram and p-chlorophenylalanine increased and decreased the observed potentiation respectively. Citalopram and p-chlorophenylalanine had no effect by per se on D-amphetamine and apomorphine-induced rotations. 2-methoxy idazoxan alone increased both ipsilateral and contralateral spontaneous rotations. Taken together, these findings indicate that an increase in noradrenergic tone by 2-methoxy idazoxan potentiates both D-amphetamine-induced ipsilateral and apomorphine induced contralateral rotations. alpha(1)-Antagonism attenuates D-amphetamine induced ipsilateral rotations and its potentiation by 2-methoxy idazoxan but not apomorphine rotations or its potentiation. Increasing and decreasing the serotonergic transmission decreases and increases D-amphetamine potentiation, whereas increases and decreases apomorphine potentiation respectively. The possible mechanisms for these findings are discussed.

Adrenergic Agents↗
PubMed1981

Effects of electrolytic and 6-hydroxydopamine lesions of the lateral hypothalamus on rotation evoked by electrical stimulation of the substantia nigra in rats.

Contralateral rotation evoked by electrical stimulation of the left substantia nigra was studied in rats before and after electrolytic or 6-hydroxydopamine (6-OHDA) lesions of the lateral hypothalamus. Electrolytic lesions (2 mA DC, 15 sec) which produced mean ipsilateral striatal dopamine depletion of 58% significantly reduced the rotation at 2 h to 14 days postlesion. 6-OHDA (8 microgram in 4 microliter) which produced mean ipsilateral striatal dopamine depletion of 93% significantly increased the rotation at 3 to 14 days postlesion. Haloperidol 0.1 and 0.5 mg/kg i.p. partially reduced rotation in both control and lesioned rats in a dose-related manner. Control and lesioned rats showed no significant differences in haloperidol sensitivity. If stimulus induced rotation were mediated by activation of dopaminergic neurons, one would have expected lesion effects in the present experiments to parallel those on rotation caused by pharmacologically evoked release of dopamine. The lesions effects we obtained on stimulus induced rotation, however, parallel those on rotation evoked by the predominantly directly acting dopamine agonist, apomorphine, rather than those on rotation evoked by the indirect (presynaptic) action of amphetamine. We suggest that contralateral rotation evoked by electrical stimulation of the substantia nigra may reflect direct activation of neurons postsynaptic to the dopaminergic nigrostriatal neurons.

Animals↗
PubMed1989

D1-dopamine receptor agonists selectively activate striatal c-fos independent of rotational behaviour.

L-Dopa and dopaminergic agonists selective for the D1- or D2-dopamine receptor subtype induce contraversive rotation in rats which have been unilaterally lesioned with injections of 6-hydroxydopamine (6-OHDA) into the substantia nigra. D-Amphetamine, which releases dopamine from neurones on the unlesioned side of the animal, causes ipsiversive rotation. These increases in rotational behaviour are mediated, at least in part, by dopamine receptors in the striatum. In unilaterally lesioned animals, L-dopa and the D1-selective agonists SKF 38393 and CY 208-243 produce contralateral rotation and induction of the nuclear proto-oncogene c-fos in the lesioned striatum. D-Amphetamine induces both ipsilateral rotation and c-fos activation in the intact striatum. Three lines of evidence, however, dissociate fos induction and rotation. First, LY 171555, a selective D2-dopamine receptor agonist, also induces contraversive rotation but this rotation is not accompanied by c-fos activation in striatum. Second, D1-dopamine agonists produce activation of striatal c-fos even if rotation is prevented by an anaesthetic. Third, rotation induced by injection of SKF 38393 into substantia nigra is not accompanied by c-fos induction. These results suggest a mechanism by which D1-dopamine receptor mechanisms may regulate long-term changes in dopaminergic systems.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1987

Changes in d-amphetamine elicited rotational behavior in rats exposed to uncontrollable footshock stress.

Male and female rats, selected on the basis of their rotational behavior in response to d-amphetamine, were exposed to either escapable footshock stress, inescapable footshock stress or no stress and were then given a shuttlebox escape task on the subsequent day. Following testing, the magnitude and direction of the animals' rotational responses to d-amphetamine were determined again. Inescapable footshock stress induced a selective change in the direction and intensity of rotational behavior that was dependent upon the subjects' sex and preexisting rotational bias. Right-rotating males and left-rotating females shifted their directional bias toward the opposite side, while left-rotating males and right-rotating females displayed increased rotation in their pre-stress direction. Significant correlations were also noted between the intensity of pre-stress rotational behavior and performance on the shuttlebox shock escape task. The results are discussed with respect to stress' actions on the mesocortical dopamine system and how this system's sex-dependent asymmetrical organization may subserve part of the organism's general reaction to uncontrollable stress.

Animals↗
PubMed1993

Sequential intravascular ultrasound characterization of the mechanisms of rotational atherectomy and adjunct balloon angioplasty.

OBJECTIVES: The purpose of this study was to use sequential intravascular ultrasound imaging before intervention, after rotational atherectomy and after adjunct balloon angioplasty to characterize the mechanisms of lumen enlargement after each. BACKGROUND: Rotational atherectomy uses a high speed, rotating, diamond-tipped elliptic burr to abrade atherosclerotic plaque to increase lumen size. In vitro studies have shown that high speed rotational atherectomy selectively abrades hard, especially calcified, plaque elements. However, rotational atherectomy procedures usually require adjunct balloon angioplasty. METHODS: Forty-eight lesions in 46 patients were treated with rotational atherectomy followed by adjunct balloon angioplasty in 44. Quantitative coronary arteriographic and intravascular ultrasound measurements of the target lesion were made before intervention, after rotational atherectomy and after balloon angioplasty. RESULTS: Before intervention, target lesion external elastic membrane area measured 17.3 +/- 5.9 mm2, lumen area measured 1.8 +/- 0.9 mm2 and plaque plus media area measured 15.7 +/- 4.1 mm2. After rotational atherectomy, lumen area increased, plaque plus media area decreased, arc of target lesion calcium decreased and 26% of the target lesions had dissection planes. After adjunct balloon angioplasty, external elastic membrane area increased, lumen area increased, plaque plus media area did not change and 77% of the target lesions had dissection planes. Arterial expansion was seen in 80% of lesions. The pattern of dissection plane location, which was predominantly within calcified plaque after rotational atherectomy, became predominantly adjacent to calcified plaque after adjunct balloon angioplasty (p = 0.008). CONCLUSIONS: Sequential intravascular ultrasound imaging shows that high speed rotational atherectomy causes lumen enlargement by selective ablation of hard, especially calcific, atherosclerotic plaque with little tissue disruption and rare arterial expansion. Adjunct balloon angioplasty further increased lumen area by a combination of arterial dissection and arterial expansion, especially of compliant, noncalcified plaque elements.

Aged↗
PubMed1996

Mechanisms and immediate and long-term results of adjunct directional coronary atherectomy after rotational atherectomy.

OBJECTIVES: The purpose of this study was to confirm the mechanisms and the immediate and long-term results of rotational atherectomy and adjunct directional coronary atherectomy. BACKGROUND: Rotational atherectomy is best suited for treating calcific stenoses, but the ability of rotational atherectomy alone to optimize lumen dimensions in large vessels is limited; this is only partly improved by adjunct balloon angioplasty. METHODS: We treated 165 lesions in 163 patients by use of rotational atherectomy and adjunct directional coronary atherectomy. Quantitative angiography and intravascular ultrasound were used for lesion analysis. A matched comparison with 208 lesions treated with rotational atherectomy and adjunct coronary angioplasty was performed. Patients were then followed up for at least 9 months, and target-lesion revascularization was assessed. RESULTS: In the 61 lesions imaged sequentially, lumen area increased from 1.7 +/- 0.8 (mean +/- 1 SD) to 3.9 +/- 1.1 mm(2) after rotational atherectomy, owing to a decrease in plaque plus media area from 16.8 +/- 5.0 to 15.2 +/- 5.2 mm(2) (both p < 0.0001). After adjunct directional coronary atherectomy, lumen area increased even more to 6.7 +/- 2.0 mm(2) (vs. 5.1 +/- 1.4 mm(2) after adjunct coronary angioplasty, p < 0.0001) as a result of both vessel expansion (18.8 +/ 5.3 to 20.8 +/- 5.7 mm(2)) and additional plaque removal (to 14.1 +/- 5.0 mm(2), all p < 0.0001). The total arcs of calcium decreased from 207 +/- 107 degrees to 166 +/- 93 degrees after rotational atherectomy and to 145 +/- 87 degrees after directional coronary atherectomy. Overall, procedural success was 96%, and final diameter stenosis was 15 +/- 17%. Target-lesion revascularization was 23%. The only independent predictor of target-lesion revascularization was a larger overall atherectomy index (84% vs. 59%, p = 0.048). CONCLUSIONS: There is a synergistic relationship between rotational atherectomy and directional coronary atherectomy in the treatment of calcific lesions. The immediate results show a high procedural success--lumen dimensions were larger and late target-lesion revascularization was lower in lesions treated with rotational atherectomy and directional coronary atherectomy than in those treated with rotational atherectomy and adjunct balloon angioplasty.

Aged↗
PubMed2004

The effects of thermal capsulorrhaphy and rotator interval closure on multidirectional laxity in the glenohumeral joint: a cadaveric biomechanical study.

PURPOSE: Arthroscopic rotator interval closure has been advocated to supplement the stabilization provided by thermal capsulorrhaphy for glenohumeral instability. However, no basic science study has examined the separate and combined effects of thermal capsulorrhaphy and rotator interval closure on the multiplane laxity of the glenohumeral joint. The purpose of this study was to measure the effects of isolated and combined thermal capsulorrhaphy and rotator interval closure on anterior, posterior, and inferior glenohumeral joint laxity in a cadaveric model. TYPE OF STUDY: Anatomic biomechanical study. METHODS: Ten cadaveric shoulders were fixed to a biomechanical testing apparatus and 5.5 lb (25 N) of force was applied to the humeral head in anterior, posterior, and inferior directions in a random order. Translation was measured in each direction on the untreated specimen (U), after arthroscopic rotator interval closure (R), after thermal capsulorrhaphy (T), and after combined rotator interval closure and thermal capsulorrhaphy (RT) with a transducer attached to a computer via data acquisition software and A/D board. Values for anterior, posterior, and inferior translation were thus obtained for U, R, T, and RT. RESULTS: Average translations in the anterior direction for the U, R, T, and RT groups were 8.0 +/- 4.4 mm, 6.7 +/- 3.3 mm, 8.5 +/- 3.6 mm, and 7.8 +/- 2.2 mm, respectively. Average translations in the posterior direction were 6.9 +/- 3.3 mm (U), 5.9 +/- 3.4 mm (R), 7.9 +/- 4.7 mm (T), and 6.8 +/- 4.0 mm (RT). Average translations in the inferior plane were 4.9 +/- 4.7 mm (U), 3.6 +/- 3.7 mm (R), 3.7 +/- 3.3 mm (T), and 2.4 +/- 1.6 mm (RT). Rotator interval closure decreased anterior, posterior, and inferior translation by 17%, 15%, and 28%, respectively, versus the untreated subjects. Thermal capsulorrhaphy increased anterior and posterior translation by 5% and 13% and decreased inferior translation by 25% versus untreated subjects. Combined RT decreased anterior, posterior, and inferior translation by 4%, 2%, and 52%, respectively. Statistical analysis revealed that rotator interval closure significantly decreased laxity values in all planes, whereas thermal capsulorrhaphy did not significantly alter laxity values versus untreated subjects. CONCLUSIONS: Isolated rotator interval closure decreased glenohumeral laxity in all directions tested, particularly inferior translation. Thermal capsulorrhaphy actually increased anterior and posterior translation in these subjects while decreasing inferior translation. We believe the trends seen reflect the clinical efficacy of rotator interval closure in the treatment of multidirectional instability. This procedure has the potential to provide improved stability versus thermal capsulorrhaphy alone, and may be considered as a supplement to or substitute for thermal capsulorrhaphy in patients with multidirectional instability. CLINICAL RELEVANCE: When treating glenohumeral instability with arthroscopic techniques, rotator interval closure may enhance stability to a greater degree than thermal capsulorrhaphy without its associated risks.

Adult↗
PubMedDate not supplied

High loading rate during spinal manipulation produces unique facet joint capsule strain patterns compared with axial rotations.

PURPOSE: Lumbar spinal manipulation (SM) is a popular, effective treatment for low back pain but the physiological mechanisms remain elusive. During SM, mechanoreceptors innervating the facet joint capsule (FJC) may receive a novel stimulus, contributing to the neurophysiological benefits of SM. The biomechanics of SM and physiological axial rotations were compared to determine whether speed or loading site affected FJC strain magnitudes or patterns. METHODS: Human lumbar spine specimens were tested during physiological rotations and simulated SM while measuring applied torque, vertebral motion, and FJC strain. During physiological rotations, specimens were actuated at T12 to 20 degrees left and right axial rotation at 2 degrees to 125 degrees per second. During SM simulations, a 7-mm impulse displacement was applied to L3, L4, or L5 at 5 to 50 mm per second. RESULTS: Physiological rotations. Increasing displacement rate resulted in significantly larger torque magnitudes (P < .001), whereas vertebral kinematics and FJC strain magnitudes were unchanged (P > .05). Physiological rotations vs SM. Applied torque and vertebral rotation magnitudes were similar across speed and vertebral level. Total vertebral translations were slightly larger during physiological rotations vs SM at a given loading rate (P < .05). Patterns of vertebral motions and FJC strain during SM and physiological rotations varied significantly with loading rate (P < .05) but not with actuation site (P > .15). CONCLUSIONS: The similar patterns observed in vertebral motion and FJC strain across actuation sites during SM and physiological rotations suggest that site specificity of SM may have minimal clinical relevance. High loading rates during lumbar SM resulted in unique patterns in FJC strain, which may result in unique patterns of FJC mechanoreceptor response.

Aged↗
PubMed2005

Frontostriatal circuits are necessary for visuomotor transformation: mental rotation in Parkinson's disease.

The mental rotation of objects requires visuospatial functions mediated by the parietal lobes, whereas the mental rotation of hands also engages frontal motor-system processes. Nondemented patients with Parkinson's disease (PD), a frontostriatal disorder, were predicted to be impaired on mentally rotating hands. Side of PD motor symptom onset was investigated because the left motor cortices likely have a causal role in hand mental rotation. The prediction was that patients with right-side onset (RPD, greater left-hemisphere dysfunction) would commit more errors rotating hands than patients with left-side onset (LPD). Fifteen LPD, 12 RPD, and 13 normal control adults (NC) made same/different judgments about pairs of rotated objects or hands. There were no group differences with objects. When rotating hands, RPD, but not LPD, made more errors than the NC group. A control experiment evaluated whether visual field of presentation explained differences between PD subgroups. In the first experiment (1A), the hand to be mentally rotated was presented in the right visual field, but here (1B) it was presented in the left visual field. Only the LPD group made more errors than the NC group. The evidence suggests a double dissociation for the RPD and LPD groups between tasks differing in visual-field presentation. The findings indicate that hemifield location of a to-be-rotated hand stimulus can cause the hemispheric frontoparietal networks to be differentially engaged. Moreover, frontostriatal motor systems and the parietal lobes play a necessary role during the mental rotation of hands, which requires integrating visuospatial cognition with motor imagery.

Aged↗
PubMed1997

The rotational diffusion of LH receptors differs when receptors are occupied by hCG versus LH and is increased by cytochalasin D.

We have examined the rotational diffusion of the luteinizing hormone (LH) receptors binding human chorionic gonadotropin (hCG) or ovine luteinizing hormone (oLH) in MA-10 Leydig tumor cells using time-resolved phosphorescence anisotropy techniques. LH receptors binding erythrosin isothiocyanate (ErITC)-derivatized oLH were rotationally mobile with rotational correlation times of 62 micros, 48 micros, 38 micros, and 29 micros at 4 degrees C, 15 degrees C, 25 degrees C, and 37 degrees C, respectively. ErITC-hCG bound to the LH receptor was rotationally immobile, showing no anisotropy decay at 4 degrees C, 15 degrees C, 25 degrees C, and 37 degrees C. To determine whether cytoskeletal components influenced the rotational diffusion of LH receptors, we measured rotational diffusion of LH receptors on MA-10 cells treated with 20 microg/ml cytochalasin D and on plasma membrane preparations. Following 1 h exposure to cytochalasin D, the rotational correlation times for hCG-occupied LH receptors were typically 11 micros at 37 degrees C compared to > 1000 micros on untreated cells. Treatment of MA-10 cells with cytochalasin B or colchicine had no affect on LH receptor rotational diffusion. Rotational correlation times for LH-occupied receptors decreased from 29 micros to 12 micros at 37 degrees C following cytochalasin D treatment. The rotational diffusion of LH receptors on plasma membrane preparations was similar to that observed for LH- and hCG-occupied receptors on intact cells treated with cytochalasin D. These various results indicate that there are differential effects of LH and hCG binding on the interactions of LH receptors with plasma membrane proteins and that microfilaments anchor the hCG- and LH-occupied receptors.

Actin Cytoskeleton↗
PubMed1986

Effect of an adolescent medicine rotation on medical students and pediatric residents.

This study evaluated the effects of an adolescent medicine rotation on the attitudes and skills in the care of adolescents of third-year pediatric residents and medical students. Competence, comfort, and prior training in four areas were assessed by a self-evaluation questionnaire. Ratings were made at the start of the year, prerotation, and post a four- to six-week rotation. Residents not taking the rotation were rated at the beginning and end of the year. In addition, pelvic-examination skills were assessed by the clinic nurse and by the patients during the first and last week of the rotation. There were no significant changes in those not taking the rotation. In those residents taking the rotation, there was no change from beginning of year to prerotation, but there were significant changes after the rotation. Only those residents taking the rotation indicated an increase in liking adolescents. Pelvic examination skills were rated significantly higher during the last week of the rotation by the nurse and patients. A one-year follow-up study continued to show significantly higher scores in those residents taking the rotation. An adolescent medicine elective may significantly improve medical students' and residents' self-assessed levels of competence, comfort, and training in adolescent health care and pelvic examination skills.

Adolescent↗
PubMed2002

Calculation of rotational setup error using the real-time tracking radiation therapy (RTRT) system and its application to the treatment of spinal schwannoma.

PURPOSE: The efficacy of a prototypic fluoroscopic real-time tracking radiation therapy (RTRT) system using three gold markers (2 mm in diameter) for estimating translational error, rotational setup error, and the dose to normal structures was tested in 5 patients with spinal schwannoma and a phantom. METHODS AND MATERIALS: Translational error was calculated by comparing the actual position of the marker closest to the tumor to its planned position, and the rotational setup error was calculated using the three markers around the target. Theoretically, the actual coordinates can be adjusted to the planning coordinates by sequential rotation of gamma degrees around the z axis, beta degrees around the y axis, and alpha degrees around the x axis, in this order. We measured the accuracy of the rotational calculation using a phantom. Five patients with spinal schwannoma located at a minimum of 1-5 mm from the spinal cord were treated with RTRT. Three markers were inserted percutaneously into the paravertebral deep muscle in 3 patients and surgically into two consecutive vertebral bones in two other patients. RESULTS: In the phantom study, the discrepancies between the actual and calculated rotational error were -0.1 +/- 0.5 degrees. The random error of rotation was 5.9, 4.6, and 3.1 degrees for alpha, beta, and gamma, respectively. The systematic error was 7.1, 6.6, and 3.0 degrees for alpha, beta, and gamma, respectively. The mean rotational setup error (0.2 +/- 2.2, -1.3 +/- 2.9, and -1.3 +/- 1.7 degrees for alpha, beta, and gamma, respectively) in 2 patients for whom surgical marker implantation was used was significantly smaller than that in 3 patients for whom percutaneous insertion was used (6.0 +/- 8.2, 2.7 +/- 5.9, and -2.1 +/- 4.6 degrees for alpha, beta, and gamma). Random translational setup error was significantly reduced by the RTRT setup (p < 0.0001). Systematic setup error was significantly reduced by the RTRT setup only in patients who received surgical implantation of the marker (p < 0.0001). The maximum dose to the spinal cord was estimated to be 40.6-50.3 Gy after consideration of the rotational setup error, vs. a planned maximum dose of 22.4-51.6 Gy. CONCLUSION: The RTRT system employing three internal fiducial markers is useful to reduce translational setup error and to estimate the dose to the normal structures in consideration of the rotational setup error. Surgical implantation of the marker to the vertebral bone was shown to be sufficiently rigid for the calculation of the rotational setup error. Fractionated radiotherapy for spinal schwannoma using the RTRT system may well be an alternative or supplement to surgical treatment.

Adolescent↗
PubMed1996

Prevalence and timing of regional myocardial dysfunction after rotational coronary atherectomy.

OBJECTIVES: This study aimed to evaluate the prevalence and time course of wall motion abnormalities associated with rotational coronary atherectomy. BACKGROUND: Although initial clinical studies found evidence of transient wall motion abnormalities after rotational coronary atherectomy, the prevalence and duration of these wall motion abnormalities are unknown. METHODS: Using simultaneous echocardiography, we prospectively evaluated 22 patients undergoing rotational atherectomy and compared their wall motion abnormalities with those of 10 patients undergoing coronary angioplasty alone. The extent of wall motion abnormality was quantified and plotted against time to produce curves of abnormal wall motion development and recovery for the two groups. RESULTS: The cumulative ischemic time was similar for the two groups ([mean +/- SD] 10.3 +/- 6 min for rotational atherectomy vs. 9.6 +/- 4.2 min for coronary angioplasty, p = 0.73). The rate of return to baseline function was significantly lower in the rotational atherectomy group than in the coronary angioplasty group (rotational atherectomy rate constant 0.069 +/- 0.079/min vs. coronary angioplasty rate constant 1.250 +/- 0.47/min, p = 0.0001). The mean time to recovery of baseline wall motion in the rotational atherectomy group (153 min, 95% confidence interval [CI] 6.5 to 3,600) was significantly longer than in the coronary angioplasty group (2.6 min, 95% CI 1.3 to 5.5, p = 0.0001). Rotational atherectomy burr time was longer in the patients who developed myocardial infarction than in those without myocardial infarction (4.7 +/- 2.4 vs. 3 +/- 1.4 min, p = 0.045). CONCLUSIONS: Transient wall motion abnormalities are common after rotational coronary atherectomy and have a longer duration than those observed after coronary angioplasty. This disparity may be a consequence of differences in the mechanisms by which rotational coronary atherectomy and coronary angioplasty produce their effect.

Aged↗
PubMed2002

Rotational muscle strength of the limb after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon.

PURPOSE: To investigate the influence of harvesting semitendinosus and gracilis tendons on the rotational muscle strength of the limb after anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Prospective study. METHODS: We performed a prospective study of 62 consecutive (34 male, 28 female) patients with ACL reconstructions using the semitendinosus and gracilis tendons. The mean age at surgery was 20.8 years. The semitendinosus tendon was harvested in 32 patients (ST group), and semitendinosus and gracilis tendons in 30 patients (STG group). The peak isokinetic torques for extension, flexion, internal rotation, and external rotation were measured before and 12 months after ACL reconstruction using the Cybex 6000B system (Cybex Division of Lumex, Ronkonkoma, NY). The rotational torque was measured at 30 degrees/sec and 120 degrees/sec. RESULTS: Before reconstruction, the mean isokinetic peak torque of the involved limb was decreased in extension and internal rotation. The mean isokinetic peak torque of the involved limb in extension recovered 12 months after ACL reconstruction; however, the weakness in internal rotation persisted. The preoperative weakness of the involved limb in extension and internal rotation recovered in the male patients, but not in the female patients after postoperative rehabilitation. The peak torque of the involved limb in internal rotation was decreased in the STG group, but not in the ST group. CONCLUSIONS: The internal rotational torque was influenced by harvesting the semitendinosus and gracilis tendons after ACL reconstruction, especially in female patients and patients from whom the gracilis tendon was harvested. Semitendinosus and gracilis tendons are important for the internal rotation of the limb and it was difficult to compensate for this function. Thus, we recommend harvesting the semitendinosus tendon only if tendon quality is sufficient to further minimize harvesting morbidity.

Adult↗
PubMedDate not supplied

In vitro effects of osteotomy angle and osteotomy reduction on tibial angulation and rotation during the tibial plateau-leveling osteotomy procedure.

OBJECTIVE: To determine the effect of osteotomy angle, reduction technique, and tibial plateau rotation angle on angular and rotational limb deformities. STUDY DESIGN: Geometric comparison using bone models. METHODS: Rotational osteotomies were made in the proximal metaphysis of artificial tibias at 0 degrees, 10 degrees, 20 degrees, -10 degrees, and -20 degrees from perpendicular with respect to either the proximodistal and craniocaudal tibial axes. Negative-numbered angles represented osteotomies made from distal to proximal or caudal to cranial. Changes in tibial angulation and torsion were measured using a 3-dimensional digitizing instrument at tibial plateau rotation angles from 0 degrees to 30 degrees at 5 degrees increments. Two osteotomy reduction techniques were used: complete osteotomy reduction and alignment of the medial cortex. The mean of 5 measurements of torsional and angular tibial deformity for each of the 9 osteotomy orientations in each reduction technique group was obtained. RESULTS: All had increasing angular and rotational deformity as tibial plateau rotation angle increased. In the medially aligned cortex group, all tibias had valgus deformity, and 8 of 9 tibias were internally rotated. In the reduced osteotomy group, minimal angular deformity was seen in tibias with osteotomy variation along the proximodistal axis; however, tibias with osteotomy variation along the craniocaudal axis had angular deformity ranging from 6.0 degrees of varus deformity to 14.3 degrees of valgus deformity. Rotational deformity was affected similarly by osteotomy variation along either axis. Reduction technique had greater affect on angular and rotational deformity than osteotomy angle variation. CLINICAL RELEVANCE: These results suggest that osteotomy reduction may play a greater role in angular and rotational deformity than osteotomy angle, although extreme osteotomy angles should be avoided. To decrease the severity of deformity, we recommend that the osteotomy be made perpendicular to the craniocaudal and proximodistal axes and be completely reduced with less regard for alignment of the medial cortex.

Animals↗
PubMed2003

The effects of job rotation on the risk of reporting low back pain.

Job rotation has been widely recommended as an administrative control to reduce the risk of developing work-related musculoskeletal disorders. However, evidence of its benefits are hard to find in the literature. The effect of job rotation on predictions for the risk of reporting low back pain was estimated using Low Back Pain Reporting (LBPR) and Time Weighted Average (TWA) approaches. Index scores calculated using the peak hand force, the peak L4/L5 shear force and the L4/L5 moment cumulated over the entire shift were used to estimate the effects of job rotation on the probability of reporting low back pain. Simulations of realistic rotations between two jobs showed that workers in low demand jobs who rotate into higher demand jobs experience a linear increase in reporting probability using the TWA approach. With the LBPR approach a step increase in reporting probability occurred because of the immediate exposure to the peak loading parameters associated with the more demanding job. With a 50-50 rotation the TWA and LBPR index scores increased by 39% and 57%, respectively. With the LBPR approach the redistribution of risk was not uniform with job rotation. The increase was greater for those who rotated into the demanding job compared to the reduction experienced by those who rotated out of the demanding job. The effects of job rotation are not easily estimated because of the complex effect that mixing jobs has on peak and cumulative tissue loading.

Adult↗
PubMed1998

Exacerbated pain in cervical radiculopathy at axial rotation, flexion, extension, and coupled motions of the cervical spine: evaluation by kinematic magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors evaluate the functional changes in patients with cervical radiculopathy and increasing symptoms after provocative maneuvers at flexion, extension, axial rotation, and coupled motions of the cervical spine. METHODS: Twenty-one patients with cervical disc herniation (n = 17) or cervical spondylosis (n = 4) in whom symptoms were elicited at flexion, extension, axial rotation, and coupled motions of the cervical spine were studied. The patients were examined inside a positioning device by using a circular surface coil for signal reception. At neutral position (0 degrees) and at provocative positions sagittal T2-weighted turbo spin-echo, axial T2-weighted two-dimensional flash sequence, sagittal three-dimensional (3D) fast imaging with steady state precision sequence and coronal 3D double-echo-in-the-steady-state sequences were obtained. The 3D sequences were reformatted in the axial and oblique coronal planes perpendicular to the exiting nerve roots. The images were evaluated for the size of disc herniations, the foraminal size and cervical cord rotation or displacement at provocative position compared with neutral position (0 degrees). RESULTS: Compared with neutral position (0 degrees), change in size of disc herniation was not found in any (0%) of the provocative positions. In five (24%) patients cervical cord rotation or displacement was noted at axial rotation. The foraminal size increased at flexion, axial rotation to the opposite side of pain and flexion combined with axial rotation to the opposite side of the pain. The foraminal size decreased at extension combined with axial rotation to the side of the pain. A decrease or no change in foraminal size was observed at either extension or axial rotation to the side of the pain. CONCLUSIONS: In patients with cervical disc herniation or cervical spondylosis, exacerbated pain at defined provocative maneuvers is related more to changes in the foraminal size and to nerve root motion with, in some cases, cervical cord rotation or displacement than to changes in the size of herniated discs.

Adult↗