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At least 541 records · Page 30Linked to original sources
PubMed1995

Quantification of three-dimensional vertebral rotations in scoliosis: what are the true values?

STUDY DESIGN: The aim of this study is to quantify differences between three-dimensional rotations in space and their calculated values, either on two-dimensional projections (radiographs or computed tomographic scans) or three-dimensional calculations using various mathematical procedures. OBJECTIVE: To use a vertebral model to quantify differences between three-dimensional rotations and their calculated values, using two-dimensional projections or various three-dimensional mathematical procedures. METHODS: A specific program allowed us to move a geometric vertebral model in space using given values and sequences of lateral, sagittal, and axial rotations. Differences in positions due to different sequences were visualized and quantified. Differences due to rotation around global or vertebral axes were considered. RESULTS: For rotations of about 10 degrees, differences are about 2 degrees between three-dimensional and projected angles. Differences increase when combined rotations are large, as generally occurs in a scoliotic spine. They reach 16 degrees for lateral and sagittal rotations of 30 degrees. CONCLUSION: Axial rotation measured on transverse projection is misleading for vertebrae rotated in space. Moreover, dealing with large three-dimensional rotations is meaningful only if the used mathematical convention is given.

Computer Simulation↗
PubMed2001

In vivo changes in the neuroforaminal size at flexion-extension and axial rotation of the cervical spine in healthy persons examined using kinematic magnetic resonance imaging.

STUDY DESIGN: In vivo flexion-extension and axial rotation magnetic resonance imaging (MRI) studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of neuroforaminal size that occur during flexion-extension and axial rotation of the cervical spine in healthy persons. SUMMARY OF BACKGROUND DATA: Kinematic MRI studies of the cervical spine were performed to obtain detailed information about the functional changes that occur in neuroforaminal size during flexion-extention and axial rotation. The results were compared with published data of in vitro functional flexion-extension and axial rotation studies of the cervical spine. METHODS: Inside a positioning device, the cervical spines of 30 healthy persons were examined in a whole-body magnetic resonance scanner from 40 degrees of flexion to 30 degrees of extension at nine different angle positions. In addition, axial rotation was performed at neutral position (0 degrees ) and at 20 degrees and 40 degrees of axial rotation to both sides. The images were analyzed with respect to the neuroforaminal size at each position using a reformatted 3D-FISP sequence. RESULTS: At flexion, widening of the neuroforaminal size of up to 31% (compared with neutral position, 0 degrees ) was observed. Conversely, at extension a decrease in the size of the neuroforamen of up to 20% was recognized. At 20 degrees and 40 degrees of ipsilateral rotation of the head, a reduction in the neuroforaminal size of up to 15% and 23%, respectively, compared with the neutral position was noted. In contrast, a widening of the foraminal size was recognized on the contralateral side of 9% and 20% at 20 degrees and 40 degrees rotation. Statistically significant differences (p <== 0.05) were found in the neuroforaminal size between different degrees of flexion and extension and in addition for axial rotation compared to neutral position (0 degrees ). CONCLUSION: Compared with the results of previous biomechanical studies of human cadaver cervical spines, kinematic MRI provides additional noninvasive data concerning the physiological changes of the neuroforaminal size during flexion-extension and axial rotation in healthy individuals.

Adult↗
PubMed2004

Hexagonal pattern instabilities in rotating Rayleigh-Bénard convection of a non-Boussinesq fluid: experimental results.

Motivated by the Küppers-Lortz instability of roll patterns in the presence of rotation, we have investigated the effects of rotation on a hexagonal pattern in Rayleigh-Bénard convection. While several theoretical models have been developed, experimental data cannot be found in the literature. In order to check the validity of the predictions and to study the effects of rotation on the behavior of the system, we present experimental results for a non-Boussinesq Rayleigh-Bénard convection with rotation about the vertical axis. Rotation introduces an additional control parameter, namely the dimensionless rotation rate Omega= 2 pi f d(2)/nu, where f is the rotation rate (in Hz), d is the thickness of the cell, and nu is the kinematic viscosity. We observe that the cell rotation induces a slow rotation of the pattern in the opposite direction (approximately Omega x 10(-4) ) in the rotating frame. Moreover, it tends to destroy the convective pattern. No oscillation of the hexagonal pattern over the range of its existence (Omega< or =6) has been observed.

Journal Article↗
PubMed1995

The direct rotation function: Patterson correlation search applied to molecular replacement.

Most rotation functions try to achieve maximal correlation between two Patterson functions by systematically rotating one and computing the overlap with the other. In contrast, the direct rotation function rotates a search model relative to the crystal unit cell and evaluates the linear correlation coefficient (Patterson correlation, PC) between squared normalized structure-factor amplitudes of the observed and calculated diffraction data. Structure factors are calculated from the rotated search model in a P1 unit cell identical to that of the target crystal. PC makes use of all self-Patterson vectors of the search model. A comparison of the direct rotation function, a real-space rotation function, and a fast rotation function suggests that the direct rotation function provides a considerable enhancement of the signal-to-noise ratio compared to other two. Combined with PC refinement, the direct rotation function was successful in solving multidomain macromolecular crystal structures.

Journal Article↗
PubMed1993

Responses of pigeon vestibulocerebellar neurons to optokinetic stimulation. II. The 3-dimensional reference frame of rotation neurons in the flocculus.

1. The complex spike activity of Purkinje cells in the flocculus in response to rotational flowfields was recorded extracellularly in anesthetized pigeons. 2. The optokinetic stimulus was produced by a rotating "planetarium projector." A light source was placed in the center of a tin cylinder, which was pierced with numerous small holes. A pen motor oscillated the cylinder about its long axis. This apparatus was placed above the bird's head and the resultant rotational flow-field was projected onto screens that surrounded the bird on all four sides. The axis of rotation of the planetarium could be oriented to any position in three-dimensional space. 3. Two types of responses were found: vertical axis (VA; n = 43) neurons responded best to visual rotation about the vertical axis, and H-135i neurons (n = 34) responded best to rotation about a horizontal axis. The preferred orientation of the horizontal axis was at approximately 135 degrees ipsilateral azimuth. VA neurons were excited by rotation about the vertical axis producing forward (temporal to nasal) and backward motion in the ipsilateral and contralateral eyes, respectively, and were inhibited by rotation in the opposite direction. H-135i neurons in the left flocculus were excited by counterclockwise rotation about the 135 degrees ipsilateral horizontal axis and were inhibited by clockwise motion. Thus, the VA and H-135i neurons, respectively, encode visual flowfields resulting from head rotations stimulating the ipsilateral horizontal and ipsilateral anterior semicircular canals. 4. Sixty-seven percent of VA and 80% of H-135i neurons had binocular receptive fields, although for most binocular cells the ipsilateral eye was dominant. Binocular stimulation resulted in a greater depth of modulation than did monocular stimulation of the dominant eye for 69% of the cells. 5. Monocular stimulation of the VA neurons revealed that the best axis for the contralateral eye was tilted back 11 degrees, on average, to the best axis for ipsilateral stimulation. For the H-135i neurons, the best axes for monocular stimulation of the two eyes were approximately the same. 6. By stimulating circumscribed portions of the monocular receptive fields of the H-135i neurons with alternating upward and downward largefield motion, it was revealed that the contralateral receptive fields were bipartite. Upward motion was preferred in the anterior 45 degrees of the contralateral field, and downward motion, was preferred in the central 90 degrees of the contralateral visual field.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Image rotation of misoriented letter strings: effects of orientation cuing and repetition.

Three experiments were designed to investigate whether the characteristic function relating response time to stimulus orientation reflects the observer imagining the rotation of the stimulus to upright (the "image rotation" hypothesis) or rotation of an internal reference frame in response to the misoriented stimulus (the "frame rotation" hypothesis). Identification times in response to misoriented words were measured in Experiment 1, whereas in Experiments 2 and 3, lexical decision times in response to misoriented letter strings were measured. Trials occurred in blocks; words within a block were presented at the same orientation. It was argued that this mode of presentation would facilitate the use of a frame rotation strategy by allowing for a gradual readjustment of an internal reference frame. The characteristic "mental rotation" function was observed in all three experiments. However, the data indicated that observers continued to imagine the rotation of the word to upright in each trial; there was no evidence of readjustment of an internal reference frame. An additional finding of interest occurred in Experiment 1, in which observers identified the same set of misoriented words across two sessions. The identification times were faster, and the slope of the mental rotation function was lower, in the second session. These results are discussed as in relation to the image rotation hypothesis of mental rotation and to "instance-based skill acquisition" (Masson, 1986) in word recognition.

Adult↗
PubMed2000

Rotating objects to determine orientation, not identity: evidence from a backward-masking/dual-task procedure.

The effects of picture-plane rotations on times taken to name familiar objects (RTs) may reflect a process of mental rotation to stored viewpoint-specific representations: the rotate-to-recognize hypothesis. Alternatively, mental rotation might be used after stored object representations are activated by a misoriented stimulus in order to verify a weak or distorted shape percept: the double-checking hypothesis. We tested these two accounts of rotation effects in object recognition by having subjects verify the orientations (to within 90 degrees) and basic-level names of 14-msec, backward-masked depictions of common objects. The stimulus-mask interval (SOA) varied from 14 to 41 msec, permitting interpolation of the SOA required for 75% accuracy (SOAc). Whereas the SOAc to verify orientation increased with rotation up to 180 degrees, the SOAc to verify identity was briefer and asymptoted at approximately 60 degrees. We therefore reject the rotate-to-recognize hypothesis, which implies that SOAc should increase steadily with rotation in both tasks. Instead, we suggest that upright and near-upright stimuli are matched by a fast direct process and that misoriented stimuli are matched at a featural level by a slightly slower view-independent process. We also suggest that rotation effects on RTs reflect a postrecognition stage of orientation verification: the rotate-to-orient hypothesis, a version of double-checking that also explains the well-known reduction in orientation effects on RTs when naming repeated objects.

Attention↗
PubMed2005

What determines positive student perceptions of extramural clinical rotations? An analysis using 2003 ADEA Senior Survey data.

Extramural clinical rotations are an integral part of many dental school curricula. Schools in The Robert Wood Johnson Foundation/The California Endowment Pipeline, Profession, and Practice program are increasing student extramural opportunities to expose students to patients of different needs, cultures, and dental delivery modes. Using data from the American Dental Education Association (ADEA) 2003 Senior Survey, the Pipeline, Profession, and Practice National Evaluation Team studied graduating dental students' perceptions about their extramural rotations. This analysis was designed to determine the factors associated with students' perception of their extramural clinical rotations: was it a positive experience in their dental education, and did it improve students' perceptions of their ability to provide care for racially, ethnically, and culturally diverse groups? The respondents were 2,950 graduating seniors who reported at least one week of extramural rotation experience. After controlling for both individual and school level characteristics, this study found that race/ethnicity, a stronger socially conscious attitudes score, number of weeks spent in extramural rotations, and the student's rating of time spent in extramural rotations were significant determinants of the extramural rotations being reported as positive experiences. With respect to improving students' ability to provide care to racially, ethnically, and culturally diverse groups, more positive student socially conscious attitudes, a greater number of weeks spent in the rotations, a stronger service orientation for selecting dentistry as a career, and the students' rating of their time spent in extramural rotations were significant determinants. In conclusion, there is some evidence that time spent in extramural rotations may be perceived as positive dental school experiences and, for some students, may prepare them to work effectively with culturally diverse patients by the time of dental school graduation.

Adult↗
PubMed1994

The influence of fixed rotational deformities of the femur on the patellofemoral contact pressures in human cadaver knees.

Patellofemoral contact pressures resulting from fixed rotational deformities of the femur were studied in human cadaver knees. The increase in the degree of fixed rotational deformities of the femur results in a nonlinear increase in patellofemoral contact pressures on the contralateral facets of the patella (i.e., external rotational deformity resulted in a contact pressure increase on the medial facet, and internal rotational deformity resulted in a contact pressure increase on the lateral facet of the patella). With the initial isometric tension of 200 N in the quadriceps tendon for 30 degrees, 60 degrees, 90 degrees, and 120 degrees knee flexion, the peak contact pressure showed no significant differences between the medial and lateral facets of the patella in its anatomic position. At 20 degrees of rotational deformity of the femur, only a slight increase was noted for the tension in the quadriceps tendon and the patellofemoral contact pressures on the contralateral facets of the patella. However, at 30 degrees rotational deformity of the femur, both the external and internal rotational deformity of the femur showed a significant increase in the tension of the quadriceps tendon and the patellofemoral contact pressures on contralateral facets of the patella. The greatest increase in patellofemoral contact pressures was observed at 30 degrees and 60 degrees knee flexion for both the external and internal rotational deformity of the femur. The external rotational deformity of the femur for all knee flexion angles showed significantly higher peak patellofemoral contact pressure increases on the medial facet of the patella as compared with the lateral patellofemoral contact pressure increase resulting from internal rotational deformity of the femur.

Aged↗
PubMed1995

[Rotational atherectomy and PTCA in complex coronary lesions (B2 and C): the immediate and long-term results].

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) in complex coronary lesions (type B2 and C of the modified AHA/ACC classification) presents a lower primary success rate and higher risk of dissection than type A and B1 lesions. An alternative approach to this lesions is coronary rotational ablation (Rotablator, Heart Technology) with complementary PTCA using low inflation pressures ("facilitated angioplasty"). MATERIALS AND METHODS: Twenty-six type B2 and C lesions in 24 patients (pts) (8 female, 16 male, age 37-80 years) were treated with coronary rotational ablation and complementary PTCA between January 1993 and December 1994 (4.7% of all interventional coronary procedures performed in this period in our laboratory). Eleven pts had stable effort angina and 13 pts had unstable, class IB, IIB, and IIC, angina. The treated vessel was the LAD in 15 cases, CX in 5, RCA in 5, and an intermediate branch in one case. Coronary rotational ablation was proposed because of the presence of two or more risk factors for uneffective or complicated PTCA: eccentricity, calcified lesions, bifurcation stenosis, lesion length > 10 mm, severe stenosis (90-99%), ostial location and bend location (45-60 degrees). No lesion showed coronary thrombus, considered as absolute contraindication to coronary rotational ablation. We used small burrs (burr/artery ratio < 0.75), and complementary PTCA was performed using low inflation pressure (< 8 atm) and long balloons for long lesions (> 10 mm) in order to minimize the risk of dissection. RESULTS: Coronary rotational ablation was successfully performed in all but two cases (24/26; 92.3%), with a reduction of the stenosis from 88 +/- 9% to 45 +/- 10% (range 30-60%). In two pts (7.7%) the procedure was complicated by acute occlusion: both pts underwent effective salvage PTCA with 30% residual stenosis. Small type A and B dissections occurred in 4/26 cases (15.4%). All but one lesions complicated by acute occlusion or dissection following coronary rotational ablation were not or only slightly calcified. Complementary PTCA was performed in all but two pts who already presented 30% residual stenosis after rotational ablation. A further reduction of stenosis to 20 +/- 9% (range 5-30%) was achieved. After complementary PTCA four pts (15.4%) developed type A and B dissections; in one of these a Palmaz-Schatz stent was implanted, whereas the remaining three pts presented a residual stenosis below 30% and no further procedures were undertaken. Overall success rate of rotational atherectomy plus salvage or complementary PTCA or stenting was 100%, and no major complications (Q-wave myocardial infarction, emergency bypass surgery or death) occurred. Three pts showed delayed coronary run-off (slow reflow) after rotational ablation, and two of these released a small amount of cardiac specific enzymes (CK MB) without ECG changes and wall motion alteration on echocardiographic examination. Clinical restenosis, defined as recurrent angina and/or positive exercise stress test, developed in 45.8% (11 pts); in all these pts restenosis was angiographically evidenced (75-99%). CONCLUSIONS: Our experience suggests that coronary rotational ablation along with complementary PTCA using low inflation pressure and long balloons is safe and effective in type B2 and C lesions if calcifications are present; however, restenosis rate remains high.

Adult↗
PubMedDate not supplied

Digital subtraction rotational angiography for aneurysms of the intracranial anterior circulation: injection method and optimization.

PURPOSE: To optimize parameters of rotational angiography for examination of the internal carotid circulation; to compare rotational angiography with standard digital subtraction angiography (DSA) in the evaluation of aneurysms of the intracranial internal carotid circulation; and to determine tolerance and safety limits of prolonged internal carotid injection angiography. METHODS: Rotational angiograms were obtained during injection of the internal carotid circulation as part of the clinical angiographic evaluation of aneurysms in 41 patients. Injection rates, X-ray delays, and fields of view were studied retrospectively. Findings at rotational angiography and standard DSA were compared. Nonionic contrast material was injected over 6 seconds, and patients were studied before and after prolonged injection angiography by physical and laboratory examination, including measurement of blood pressure, pulse, and intracranial pressure. RESULTS: Vascular conspicuity was equivalent at carotid injection rates of 4 and 5 mL/s delivered over 6 seconds. At 3 mL/s, more image manipulation was required to see small vascular structures. One-second X-ray delay combined with 6-second injection duration provided the best arterial depiction of intracranial vessels from start to end of rotational angiography. Maximal rotational resolution was with a 17-cm field of view. Identification of aneurysms and small vessels was equivalent at all injection rates. Aneurysm detection was equivalent with rotational angiography and DSA. In 9 of 31 aneurysms, the neck was defined more clearly with rotational angiography than with DSA, compared with 2 of 31 that were seen better with DSA. Aneurysms of the intracranial internal carotid circulation were seen with rotational angiography and not DSA in 12 of 41 cases. No change was noted in clinical or laboratory findings. CONCLUSION: Rotational angiography provided better definition of the aneurysmal neck and greater clarity of aneurysms than did DSA; it also improved the level of confidence in predicting the presence or absence of aneurysms, especially in the anterior communicating artery; however, in our small series it did not significantly increase the detection of aneurysms. Prolonged injection angiography was well tolerated in all patients.

Aneurysm, Ruptured↗
PubMed2004

Biomechanical analysis of tendon transfers for massive rotator cuff tears.

OBJECTIVE: To determine why certain tendon transfers are mechanically more effective than other tendon transfers for the treatment of a massive rotator cuff tear. DESIGN: A tendon transfer procedure of latissimus dorsi, teres major or a combination of these two to the insertions of either teres minor, infraspinatus, supraspinatus, or subscapularis is simulated using a biomechanical musculoskeletal model of the upper extremity. BACKGROUND: Massive rotator cuff tears are not easily repaired. To compensate for the loss of rotator cuff function, techniques such as muscle transfers are developed. METHODS: Three range of motion tasks were used as input to the Delft shoulder and elbow model. The muscle parameters of the Delft shoulder and elbow model were modified to simulate a rotator cuff tear. A biomechanical analysis of the transferred muscles was performed, taking outcome variables such as moment arms, muscle length and muscle force into account. RESULTS: Due to the massive rotator cuff tear, an elevation and external rotation moment is lost. When the tendon was transferred to the insertions of infraspinatus or supraspinatus, the humerus was capable of elevating and externally rotating. CONCLUSIONS: On the basis of mechanical parameters such as moment arms, muscle length and force it can be concluded that a tendon transfer of the teres major to the supraspinatus insertion will produce the best functional outcome in the treatment of massive rotator cuff tears. RELEVANCE: To find biomechanical evidence for an optimal tendon transfer that will lead to improved treatment of patients with a massive rotator cuff tear.

Biomechanical Phenomena↗
PubMed2002

Rotator cuff alterations resulting from humeral head fractures.

Most complex humeral head fractures are associated with a longitudinal tear of the rotator cuff. Reconstruction of this tear is frequently omitted from surgical reduction and fixation procedures. In 48 patients treated by surgery or by conservative means, we investigated the relationship between rotator cuff integrity and the functional results. The rotator cuff was assessed by ultrasonography, the functional results by the Constant Score. Common signs of rotator cuff alterations were partial or complete atrophy. In all patients affected, a longitudinal defect located at the rotator interval was detected. A classification of rotator cuff alterations resulting from humeral head fractures was introduced, yielding three categories: none, moderate, or severe. In three patients, sonographic results were confirmed by magnetic resonance imaging (MRI). Rotator cuff alterations were often associated with displaced consolidation results. Furthermore, the integrity of the rotator cuff significantly correlated with the function achieved. The results support the need for a careful rotator cuff repair in order to optimise treatment results.

Adult↗
PubMed2003

Rotator cuff repair with bioabsorbable screws: An in vivo and ex vivo investigation.

PURPOSE: The purpose of this study was to evaluate in vivo the clinical outcomes of rotator cuff repairs with bioabsorbable screws compared with metal suture anchors, and to compare the ex vivo initial load to failure of rotator cuff repairs using 3 different bioabsorbable screws, suture anchors, and transosseous sutures. TYPE OF STUDY: In vivo clinical outcomes investigation, and ex vivo biomechanical study. METHODS: Three cohorts of patients with rotator cuff tears that measured less than 4 cm(2), were sequentially repaired with Mitek Rotator Cuff QuickAnchors (Mitek Surgical Products, Norwood, MA) (n = 9), Arthrex Headed Bio-Corkscrews (n = 9) (Arthrex, Naples, FL), and Mitek Rotator Cuff QuickAnchors (n = 9). Patients were systematically assessed with a specific shoulder questionnaire and 23 shoulder tests performed preoperatively and at 1 and 6 weeks, 3 and 6 months, and 1 year postoperatively. A correlative ex vivo biomechanical study was performed on 53 ovine shoulders to evaluate the initial failure load properties of bioabsorbable screws compared with fixation with suture anchors and transosseous sutures. RESULTS: In the in vivo portion of the study, the cohort treated with the Headed Bio-Corkscrew demonstrated no improvement on any measured parameter until 1-year after rotator cuff repair. In contrast, shoulders repaired with Mitek Rotator Cuff QuickAnchors demonstrated improved overall shoulder function as early as 6 weeks postoperatively (P =.002), had a better constant score at 1-year after repair (88 +/- 9 v 73 +/- 17; P =.016), and a lower rate of revision rotator cuff repair (P =.029). In the ex vivo portion of the study, the bioabsorbable headed screws, Headed Bio-Corkscrew (100 +/- 30 N) and BioTwist (76 +/- 35 N), had inferior initial failure load properties compared with suture anchors (140 +/- 36 N) and transosseous sutures (147 +/- 68 N). In contrast, the BioCuff (190 +/- 56 N), a bioabsorbable implant that used a screw and serrated washer design, had equivalent initial failure load properties as the suture repairs. CONCLUSIONS: This investigation had poorer early outcomes, a lower shoulder functional score 1-year after repair, and a higher rate of repeat surgery in patients who had their rotator cuff repaired with a bioabsorbable screw than in patients who had their shoulders repaired with a standard metal suture anchor. Furthermore, the biomechanical testing demonstrated a lower tensile load to failure in the tendons repaired with a simple screw design compared to suture anchors with a mattress stitch. Of note, the implant that used a screw and washer design demonstrated a greater ability to resist initial tensile load.

Absorbable Implants↗
PubMedDate not supplied

MR imaging of rotator cuff injury: what the clinician needs to know.

The rotator cuff muscles generate torque forces to move the humerus while acting in concord to produce balanced compressive forces to stabilize the glenohumeral joint. Thus, rotator cuff tears are often associated with loss of shoulder strength and stability, which are crucial for optimal shoulder function. The dimensions and extent of rotator cuff tears, the condition of the involved tendon, tear morphologic features, involvement of the subscapularis and infraspinatus tendons or of contiguous structures (eg, rotator interval, long head of the biceps brachii tendon, specific cuff tendons), and evidence of muscle atrophy may all have implications for rotator cuff treatment and prognosis. Magnetic resonance imaging can demonstrate the extent and configuration of rotator cuff abnormalities, suggest mechanical imbalance within the cuff, and document abnormalities of the cuff muscles and adjacent structures. A thorough understanding of the anatomy and function of the rotator cuff and of the consequences of rotator cuff disorders is essential for optimal treatment planning and prognostic accuracy. Identifying the disorder, understanding the potential clinical consequences, and reporting all relevant findings at rotator cuff imaging are also essential.

Health Knowledge, Attitudes, Practice↗
PubMed2005

A prospective, double-blind, randomized clinical trial comparing subacromial injection of betamethasone and xylocaine to xylocaine alone in chronic rotator cuff tendinosis.

BACKGROUND: Rotator cuff tendinosis is a common problem with significant health and economic effects. Nonoperative management includes the widespread use of subacromial steroid injections despite the lack of evidence of its efficacy. HYPOTHESIS: A subacromial injection of betamethasone will be more effective than xylocaine alone in improving the quality of life, impingement sign, and range of motion in patients who have chronic rotator cuff tendinosis or partial rotator cuff tears. STUDY DESIGN: Randomized controlled clinical trial; Level of evidence, 1. METHODS: Patients with rotator cuff tendinosis or partial cuff tear with symptoms longer than 6 months, with failure of 6 weeks of physical therapy and 2 weeks of nonsteroidal anti-inflammatory drugs, who were older than 30 years of age, and who showed >50% improvement with the Neer impingement test were stratified for Workplace Safety and Insurance Board status and previous injection. Outcome measures--the Western Ontario Rotator Cuff Index; American Shoulder and Elbow Surgeons standardized form; Disabilities of the Arm, Shoulder and Hand; active forward elevation; active internal rotation; active external rotation; and the Neer impingement sign--were assessed at 2, 6, 12, and 24 weeks after injection. The injection into the subacromial space contained either 5 mL of 2% xylocaine alone or 4 mL of 2% xylocaine and 1 mL (6 mg) of betamethasone in an opaque syringe. RESULTS: In 58 patients (betamethasone group, n = 30; xylocaine group, n = 28), the authors found no statistically significant difference between the 2 treatment groups for all outcomes and time intervals. The scores for the Western Ontario Rotator Cuff Index at 3 months were xylocaine = 45.4% +/- 13% and betamethasone = 56.3% +/- 17% (P = .13). At 6 months, the scores were xylocaine = 51% +/- 32% and betamethasone = 59% +/- 26% (P = .38). All other outcomes showed similar values. As well, similar results were found for 2 and 6 weeks after injection. Both groups showed improvement from baseline in all outcomes. CONCLUSIONS: With the numbers available for this study, the authors found betamethasone to be no more effective in improving the quality of life, range of motion, or impingement sign than xylocaine alone in patients with chronic rotator cuff tendinosis for all follow-up time intervals evaluated.

Anesthetics, Local↗
PubMed1999

Greater tuberosity changes as revealed by radiography: lack of clinical usefulness in patients with rotator cuff disease.

OBJECTIVE: Studies linking greater tuberosity findings on radiographs with rotator cuff disease have largely been uncontrolled and biased toward more severe disease. We correlated greater tuberosity changes seen on radiography with rotator cuff disease seen on MR images in a broadly symptomatic patient population. MATERIALS AND METHODS: Both radiography and MR imaging were performed in 108 shoulders. Unaware of the MR imaging findings, three radiologists independently reviewed the radiographs for cortical thickening, subcortical sclerosis, and cystlike lesions in the humeral greater tuberosity. Interobserver agreement was analyzed using kappa statistics. We correlated the radiographic findings with MR imaging evidence of rotator cuff tears and tendonopathy. The positive predictive value of each finding for rotator cuff disease was also calculated. RESULTS: Interobserver agreement for the three radiographic findings was poor to fair: Kappa values ranged from .06 to .41. Cortical thickening and subcortical sclerosis were not seen more frequently in shoulders with rotator cuff disease than in normal shoulders. Cystlike lesions were more prevalent in shoulders with rotator cuff disease, but the association reached statistical significance (p < .05) for one observer only. Positive predictive values for each finding were low (14-48% for predicting full-thickness rotator cuff tears). CONCLUSION: Cortical thickening of the greater tuberosity and subcortical sclerosis are not associated with rotator cuff disease. For some observers, identifying cystlike lesions is associated with rotator cuff disease, but the clinical usefulness of the observation is limited by high interobserver variability and poor positive predictive value.

Female↗
PubMed2006

Relation between rotation in the 6-OHDA lesioned rat and dopamine loss in striatal and substantia nigra subregions.

The relation between the rotation response to drug-induced activation of the dopamine (DA) receptor in the rat unilaterally lesioned with 6-hydroxydopamine (6-OHDA) in the substantia nigra (SN) and the loss of DA in subregions of the SN and caudate-putamen (C/PUT) is not clear. Here this relation was examined in 23 rats classified as rotators to amphetamine (5 mg/kg). After their response was characterized in terms of ipsilateral rotation, contralateral rotation, and oral stereotypy in one place, they were divided into high, medium, low, and very low rotators. The loss of DA in each group was visualized on brain sections immunoreacted to tyrosine hydroxylase (TH). The density of the TH label on the side of the lesion was compared to that on the intact side. In the ventral midbrain, the density was determined in the SN subdivided into far lateral, lateral, central, and medial subregions and also in the ventral tegmental area (VTA). In the forebrain, it was determined in the C/PUT subdivided into lateral, central, and medial subregions and also in the nucleus accumbens (ACC). These measurements led to three principal findings. The first was a positive overall correlation between rotation and loss of TH label. The second was a correlation between rotation and penetration of the loss from the lateral subregions into more medial areas. The third was a larger loss in SN and VTA (midbrain) than in C/PUT and ACC (forebrain). These findings show that rotation depended not only on the overall loss of DA but also on its distribution across subregions. The loss in the lateral subregion, always the largest regardless of the rate of rotation, may have been the first step in inducing the motor abnormality, and the loss in the central and medial subregions may have served to enhance the abnormality due to the loss in the lateral subregion.

Amphetamine↗