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Biomedical subjects

E Itoi

Publications and source records attributed to E Itoi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Intraarticular pressure of the shoulder.

Nine fresh frozen cadaveric shoulders were used to examine the changes in intraarticular pressure (IAP) of the shoulder joint and the position of the humeral head under various loads to determine the relationship between these parameters. All the soft tissues superficial to the rotator cuff were removed. The position of the humerus relative to the scapula was monitored using an electromagnetic tracking system before and after venting the capsule with 0, 0.5, and 1.0 kg of load applied to the humerus inferiorly in addition to the weight of the arm. Simultaneously, the IAP was monitored using a pressure transducer before venting the capsule. Venting had a significant effect on the position of the humeral head: the positions of the head after venting were significantly lowered in all loading conditions. The average IAP was -76 cm H2O without load, and the value decreased in a linear fashion with increased load; the correlations were significant in four of six shoulders without dislocation. The correlations were less significant between the pressure and the position, and there were no significant correlations between the load and the position. IAP, which is determined primarily by the load applied, is important to stabilize the shoulder inferiorly. Because IAP is intimately related to the external load and the response is specific to individuals, examination of IAP response to external load may be helpful in characterizing various instabilities of the shoulder.

Cadaver↗
PubMed1993

Stabilising function of the biceps in stable and unstable shoulders.

We studied the contributions of the long and short heads of the biceps (LHB, SHB) to anterior stability in 13 cadaver shoulders. The LHB and SHB were replaced by spring devices and translation tests at 90 degrees abduction of the arm were performed by applying a 1.5 kg anterior force. The position of the humeral head was monitored by an electromagnetic tracking device with or without an anterior translational force; with 0 kg, 1.5 kg or 3 kg loads applied on either LHB or SHB tendons in 60 degrees, 90 degrees or 120 degrees of external rotation; and with the capsule intact, vented, or damaged by a Bankart lesion. The anterior displacement of the humeral head under 1.5 kg force was significantly decreased by both the LHB and SHB loading in all capsular conditions when the arm was in 60 degrees or 90 degrees of external rotation. At 120 degrees of external rotation, anterior displacement was significantly decreased by LHB and SHB loading only when there was a Bankart lesion. We conclude that LHB and SHB have similar functions as anterior stabilizers of the glenohumeral joint with the arm in abduction and external rotation, and that their role increases as shoulder stability decreases. Both heads of the biceps have been shown to have a stabilising function in resisting anterior head displacement, and consideration should therefore be given to strengthening the biceps during rehabilitation programmes for chronic anterior instability of the shoulder.

Analysis of Variance↗
PubMed1993

Capsular properties of the shoulder.

The purpose of this study was to determine the structural properties of the capsule of the glenohumeral joint. Twelve fresh frozen cadaveric shoulders were studied. Capsular strips were prepared from four different sites (anterior, posterior, superior, and inferior) of the capsule. One end of the capsular sections was left attached to the humerus, and the other excised was fixed in a clamp of an Instron universal testing machine. Maximum load, strength (maximum stress), and modulus of elasticity of these four capsular portions were measured. The most common mode of failure was tear at the midsubstance (68%), followed by tear at the clamp-capsule junction (23%), and detachment from the humerus (9%). The posterior capsule (1.0 +/- 0.4 mm) was thinner than the anterior (1.8 +/- 0.3 mm), superior (1.6 +/- 0.4 mm), and inferior capsule (1.5 +/- 0.3 mm). Among the four portions of the capsule, the posterior capsule showed the greatest strength (216.6 +/- 58.2 kg/cm2) and modulus of elasticity (683.1 +/- 228.8 kg/cm2), whereas the superior capsule showed the least strength (82.4 +/- 33.5 kg/cm2). There were no significant differences in maximum load. The greater strength of the posterior capsule may be one explanation for the low incidence of posterior shoulder dislocation.

Biomechanical Phenomena↗
PubMed1993

Bulk effect of rotator cuff on inferior glenohumeral stability as function of scapular inclination angle: a cadaver study.

Eleven fresh cadaver shoulders were studied to determine the static contribution (bulk effect) of the rotator cuff on inferior glenohumeral stability provided by scapular inclination. All musculature, including the rotator cuff, was removed. The position of the humerus relative to the scapula was recorded using an electromagnetic tracking device under conditions of no force and 1.5 kg of inferior translation force applied to the humerus, with the arm in the hanging position (sulcus test) and then in 90 degrees abduction (Abduction-Inferior Stability test = ABIS test), with the scapula inclined referable to the vertical line at -15 degrees, 0 degrees, 15 degrees and 30 degrees in the sulcus test and at 15 degrees, 30 degrees, 45 degrees and 60 degrees in the ABIS test. In the sulcus test without load, all shoulders dislocated at scapular inclination angles of -15 degrees and 0 degrees, whereas no shoulders dislocated at 30 degrees. The angle of scapular inclination had a significant effect on humeral head positions (p < 0.0001), with the head position at -15 degrees and 0 degree being lower than at 15 degrees, which was lower than at 30 degrees. In the ABIS test, none of the shoulders dislocated, although the effect of the angle of scapular inclination was significant (p < 0.0001), with the position of the humeral head being higher at 15 degrees than at other angles of inclination. Comparison of these data and previously reported data with the cuff intact showed no significant effect of rotator cuff removal on humeral head position and displacement in both tests. Therefore, we conclude that the static condition of the rotator cuff has no significant effect on the stabilizing function of scapular inclination. The stabilizing mechanism of scapular inclination seems to be associated with the bony configuration and/or anatomy and biomechanical properties of the superior capsuloligamentous structures.

Adult↗
PubMed1993

Kinematic and stability of the Norway elbow. A cadaveric study.

We investigated the effect of simulated muscle loading and the contribution of the radial head to stability of the Norway elbow in 6 cadavers using an electromagnetic tracking device. The kinematics of the elbow after implantation of the prosthesis were similar to the intact elbow in their valgus-varus orientation, however, the forearms were slightly externally rotated, probably due to a small amount of external rotation of the humeral components at the time of implantation. The valgus-varus laxity limit of the implants were greater than in the intact specimens averaging 8.0 and 5.6 degrees, respectively. Simulated muscle loading stabilized both the intact and the Norway elbows. Excision of the radial head after implant arthroplasty increased their valgus-varus laxity, suggesting that preservation of the radial head may be indicated if it is not too severely involved by the underlying disease process. The laxity permitted by the prosthesis articulation is greater than that measured after implantation of the Norway arthroplasty. This suggests that the prosthesis may behave as an unconstrained arthroplasty. This should minimize the stress experienced by the bone-cement interface and may reduce the incidence of loosening. The laxity of the elbows after joint arthroplasty were only slightly greater than normal, possibly explaining the low incidence of prosthesis dislocation which has been observed with clinical use.

Aged↗
PubMed1992

Rotator cuff tears in anterior dislocation of the shoulder.

We diagnosed 16 rotator cuff tears in 109 shoulders in 104 patients with a traumatic anterior dislocation. Twelve of these were followed up for an average of 32 months. A surgical repair of the cuff was carried out in eleven and the results were satisfactory in eight (73%) regardless of a Bankart lesion. The repair of a torn cuff seems to be sufficient to stabilise the shoulder in elderly patients, even when a Bankart lesion is present and is not repaired.

Aged↗
PubMed1992

Long-term treatment with 1 alpha-hydroxyvitamin D3 with calcium supplement in spinal osteoporotic patients.

The long-term effect of 1 alpha-hydroxyvitamin D3 and calcium lactate in osteoporotic patients was evaluated by the bone mineral density (BMD) measured at the distal one third and one sixth of the radius and by the vertebral fracture rate. Forty-five osteoporotic patients medicated for 1 to 13 years (treated group) and 11 osteoporotic patients with no medication for 1 to 3 years (control group) were compared. The BMD of the treated group remained unchanged for the first 4 (one-third site) and 6 years (one-sixth site), followed by significant decreases, whereas that of the control group decreased significantly at the second and third year. The effect on BMD was more prominent in the patients with lower initial BMD. The vertebral fracture rate of the treated group was significantly less than that in the control group at the third year. No serious side effects were recognized. Overall, we believe 1 alpha-hydroxyvitamin D3 with calcium supplement can be considered a safe and effective agent for long-term use in osteoporotic patients.

Aged↗
PubMed1992

Incomplete rotator cuff tears. Results of operative treatment.

Thirty-eight shoulders of 36 patients with incomplete rotator cuff tears surgically repaired were evaluated, with an average follow-up period of 4.9 years. The average age at operation was 52.2 years. Three types of incomplete tears were identified: superficial (12 shoulders), intratendinous (three), and deep surface tears (23). Full-thickness cuff involving the lesion was resected and repaired by side-to-side suture (13 shoulders), side-to-bone suture (eight), fascial patch grafting (16), or side-to-bone suture with fascial patch grafting (one). The overall results were satisfactory in 31 shoulders (82%). The results were not affected by the tear types, operative methods, or follow-up period. The patients with poor results were associated with major complications other than rotator cuff tears or with insufficient resection of the damaged cuff. When the full-thickness cuff involving the lesion is completely resected and repaired, long-term satisfactory results can be anticipated in a high percentage of patients regardless of tear types.

Adolescent↗
PubMed1992

Conservative treatment of rotator cuff tears.

Among 124 shoulders in 114 patients with complete rotator cuff tears who had been treated conservatively from 1980 until 1989, 62 shoulders in 54 patients were observed to identify the findings on initial examinations and correlate them with the final results. The follow-up period averaged 3.4 years. According to modified criteria of Wolfgang, 51 shoulders in 45 patients (82%) rates satisfactory (excellent or good). The overall scores of pain, motion, and function improved significantly. The results were less satisfactory in patients observed more than six years. The patients with satisfactory results (Group 1) and unsatisfactory results (Group 2) among those observed more than five years were compared. In Group 1, the scores of pain, motion, and strength improved significantly at follow-up examinations, whereas those of function did not. In Group 2, no improvement was recognized in any categories. The only significant differences in the initial findings between the two groups were the active abduction angle and the abduction strength: the patients in Group 1 retained a good range of motion and strength, whereas those with unsatisfactory results had a limited range and muscle weakness on first examinations. Conservative treatment affords satisfactory results when it is given to the patients with well-preserved motion and strength, although in some cases function may deteriorate with time.

Adult↗
PubMed1991

Roentgenographic analysis of posture in spinal osteoporotics.

This study was designed to investigate the relationship between postural deformities--including both the spine and lower extremities--and clinical symptoms in spinal osteoporotics. Lateral roentgenographic films of 100 osteoporotic patients taken in a standing position were analyzed. Thoracic kyphosis, a primary deformity of the osteoporotic spine, appeared compensated by the lumbar spine, sacroiliac joint, hip joint, and knee joint, respectively. Low-back pain was highly associated with decreased lumbar lordosis and increased sacropelvic angle, suggesting that the sacroiliac joint was one of the causes of low-back pain.

Aged↗
PubMed1990

Long-term observations of vertebral fractures in spinal osteoporotics.

The changes in the number and distributions of vertebral fractures were studied from the long-term observations (average 7 years) of 21 spinal osteoporotic patients. Distribution of wedge fractures was biphasic with peak frequencies at the midthoracic and thoracolumbar spine. Biconcave fractures occurred predominantly in the lumbar spine. These patterns of distribution did not change during the period of observation. The rate of biconcave fracture increased, the rate of wedge fracture decreased, and that of collapse remained the constant in follow-up. The changes in the number of fractures were divided into three types: increasing, plateau, and unchanged type. With the advance of osteoporosis, the increasing type was considered to change into the plateau type, which is probably the terminal stage of spinal osteoporosis. The unchanged type, in contrast, was distinct from the other two types because of increased spinal bone mineral density and decreased urinary calcium, which suggests that spinal osteoporosis is heterogeneous with regard to calcium metabolism.

Aged↗
PubMed1990

Tenotomy and postoperative brace treatment for muscular torticollis.

A postoperative corrective brace for congenital muscular torticollis is introduced and the results and indications for its use are presented. Thirty-three of 55 patients who underwent open tenotomy of the sternocleidomastoid muscle with application of the brace following surgery were evaluated in follow-up. Tenotomy was performed at the sternoclavicular origin of the muscle. The mean age at operation was six years; the mean follow-up period was seven years. The results were good in 21 patients (64%), fair in seven (21%), and poor in five (15%). Facial asymmetry remained in all patients over the age of ten who underwent operation. Alopecia, one of the complications of the brace, was found only in patients under age five. This combined treatment with tenotomy and postoperative brace is considered best indicated for patients between six and ten years of age.

Adolescent↗
PubMedDate not supplied

Magnetic resonance arthrography in the assessment of anterior instability of the shoulder: comparison with double-contrast computed tomography arthrography.

Forty-seven shoulders with traumatic anterior instability were studied by magnetic resonance arthrography (MRA) and computed tomography arthrography (CTA) to compare the diagnostic performance of these examinations in the evaluation of Bankart lesions. All shoulders were examined by arthroscopy to verify the lesions. Labral damage evaluated by MRA and by CTA correlated significantly with arthroscopic findings (MRA, r = 0.55, p < 0.0001; CTA, r = 0.45, p = 0.0050). MRA possessed higher sensitivity in detecting torn labra (MRA, sensitivity = 87%, specificity = 75%; CTA, sensitivity = 33%, specificity = 88%). In detecting displaced labra, sensitivity and specificity were 65% and 94% for MRA and 75% and 69% for CTA. The inferior glenohumeral ligament was depicted as a lax structure in 74% by MRA but in only 21% by CTA. We conclude that MRA is superior to CTA in detecting lesions associated with shoulder instability.

Adolescent↗
PubMedDate not supplied

Shoulder muscle moment arms during horizontal flexion and elevation.

The instantaneous muscle moment arms of 10 shoulder muscles including the three portions of the deltoid and the rotator cuff and scapulohumeral muscle groups during four specified glenohumeral motions were calculated. Moment arm values were derived from a plot of tendon excursion versus glenohumeral joint rotation angle during horizontal flexion along the 90 degrees elevation plane and elevation in the sagittal, scapular, and coronal planes. The deltoid had the largest moment arm in elevation. The anterior deltoid has a larger moment arm in the anterior planes, whereas the midportion is greater in the scapular and coronal planes. The muscles with the largest depressor (adductor) moment arms are the pectoralis major, latissimus dorsi, and teres major. Contrary to the findings of other investigators, the supraspinatus and infraspinatus have a smaller potential elevation torque in the scapular plane than has been previously reported. Furthermore the subscapularis may potentially be a more important elevator in the scapular plane than either the supraspinatus or infraspinatus, especially in the latter phases of motion. The pectoralis major has the largest horizontal flexion moment arm with the humerus elevated 90 degrees, whereas the posterior deltoid and infraspinatus have the largest horizontal extension moment arms in this plane.

Adult↗
PubMedDate not supplied

Skin temperature of the shoulder: circadian rhythms in normal and pathologic shoulders.

Circadian rhythm of the shoulder skin temperature was studied in 21 shoulders of 20 patients with rotator cuff tears (average age, 58 years) and 4 shoulders of 4 patients with rotator cuff tendinitis (average age, 34 years). Fourteen of the 23 uninvolved shoulders with no abnormalities on magnetic resonance imaging were also studied as normal shoulders. With a portable thermometer with the probes attached to the anterior surface of both shoulders, the skin temperature was recorded every 5 minutes from 1:00 PM to 9:00 AM (20 hours). Both the normal and cuff tear shoulders showed a similar circadian rhythm with the temperature at night significantly lower than the temperature during the daytime (P < .0001). On the other hand, the tendinitis shoulders did not show this circadian rhythm; the temperature did not change significantly through the range of measurement. We conclude that the skin temperature shows a circadian rhythm in normal shoulders, and this rhythm may be affected by certain pathologic conditions of the shoulder.

Adult↗