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PubMed1998

Late treatment of brachial plexus palsy secondary to birth injuries: rotational osteotomy of the proximal part of the humerus.

We retrospectively reviewed the results of rotational osteotomy that had been performed distal to the surgical neck of the humerus in twenty-two patients who had sustained an injury of the brachial plexus at birth. Eighteen patients had a lesion of the superior trunk of the brachial plexus (the fifth and sixth cervical nerve roots), and four had involvement of the entire brachial plexus. The patients ranged in age from four to seventeen years old (average age, ten years and three months old) at the time of the operation. The average duration of follow-up was fourteen years (range, two to thirty-one years). Preoperatively, the patients had been unable to perform self-care activities, such as grooming, feeding, and washing themselves, because of limited active external rotation or fixed internal rotation of the shoulder. All patients had decreased strength of the lateral rotator and abductor muscles and normal strength of the subscapularis and pectoralis major muscles. Radiographs showed some flattening of the humeral head, and four patients had posterior subluxation of the humeral head. A lateral rotational osteotomy of the proximal part of the humerus was performed between the insertions of the subscapularis and pectoralis major muscles. The site of the osteotomy was stabilized with catgut sutures in the periosteum in ten patients and with one or two staples in twelve. The extremity was immobilized in a plaster shoulder-spica cast for six weeks. At the latest follow-up evaluation, the average increase in active abduction was 27 degrees (range, 0 to 60 degrees) and the average increase in the arc of rotation was 25 degrees (range, 5 to 85 degrees). Supination of the forearm also had increased commensurate with the increase in external rotation. The appearance of the extremity had improved as well.

Activities of Daily Living↗
PubMed2001

Surgical repair of chronic rotator cuff tears. A prospective long-term study.

BACKGROUND: Rotator cuff disease or injury is one of the most frequently seen orthopaedic conditions, and surgical repair of rotator cuff tears is a common procedure. A prospective analysis of the operation, with consistent assessment of patient characteristics, variables associated with the rotator cuff tear and repair techniques, and outcome factors, was performed. METHODS: One hundred and five shoulders with a chronic rotator cuff tear underwent open surgical repair and acromioplasty between 1975 and 1983. The patients were followed for an average of 13.4 years (range, two to twenty-two years). There were sixteen small tears, forty medium tears, thirty-eight large tears, and eleven massive tears. The tears were repaired directly (seventy-two tears), by V-Y plasty (twelve), by tendon transposition (twenty), or by reinforcement with a fascia lata graft (one). The long head of the biceps had been previously torn in eleven shoulders and was tenodesed in three other shoulders. In fifty-six shoulders, the distal part of the clavicle was excised for treatment of degenerative arthritic changes, often associated with osteophyte formation. RESULTS: Satisfactory pain relief was obtained in ninety-six shoulders (p < 0.0001). There was significant improvement in active abduction (p < 0.001) and external rotation (p < 0.007) as well as in strength in these directions of movement (p < 0.03 and p < 0.002, respectively). At the latest follow-up evaluation, the result was rated as excellent for sixty-eight shoulders, satisfactory for sixteen, and unsatisfactory for twenty-one. Tear size was the most important determinant of outcome with regard to active motion, strength, rating of the result, patient satisfaction, and need for a reoperation. Older age, less preoperative active motion, preoperative weakness, distal clavicular excision, and a transposition repair technique were all associated with larger tear size. There were eight reoperations; five were for rerepair of a persistent or recurrent rotator cuff tear. CONCLUSIONS: Standard tendon repair techniques combined with anterior acromioplasty, postoperative limb protection, and monitored physiotherapy can produce consistent and lasting pain relief and improvement in range of motion. Improving the results of this procedure will depend upon the development of new techniques to address the active motion and strength deficiencies following repair of massive rotator cuff tears.

Acromion↗
PubMed2006

The effect of ankle rotation on cutting of the tibia in total knee arthroplasty.

BACKGROUND: Extramedullary alignment guides are commonly used to prepare the tibia during total knee arthroplasty. One disadvantage is that the guide is easily affected by the position of the ankle joint. The tibia may have a rotational mismatch between its proximal and distal ends. We hypothesized that a rotational mismatch might cause incorrect positioning of an extramedullary alignment guide and evaluated such a mismatch on the predicted postoperative coronal alignment of the tibia. METHODS: Fifty-three osteoarthritic knees with varus deformity in fifty-one patients were evaluated with use of computerized tomography scans before total knee arthroplasty. We defined one anteroposterior axis of the ankle joint and five different anteroposterior axes of the proximal aspect of the tibia using three-dimensional bone models from the computerized tomography data. We measured the rotational angle between the anteroposterior axis of the ankle joint and the proximal part of the tibia. The distal end of the extramedullary guide was placed in front of the center of the ankle joint (on the line of the extended anteroposterior axis of the ankle joint), and the proximal end was placed on the line of the extended anteroposterior axis of the proximal part of the tibia. We established spatial coordinates to evaluate the effect of the rotational angle on the predicted postoperative coronal alignment of the tibia and calculated the presumed tibial coronal alignment. RESULTS: The rotational angle was positive (3.6 degrees to 19.7 degrees) for all of the anteroposterior axes of the proximal aspect of the tibia, indicating that the ankle joint was externally rotated relative to the proximal part of the tibia. The predicted tibial coronal alignment was varus (0.5 degrees to 5.1 degrees) for all of the anteroposterior axes of the proximal part of the tibia. CONCLUSIONS: When an extramedullary alignment guide is used to prepare the tibia in total knee arthroplasty, varus alignment of the tibial component can occur because of a rotational mismatch between the proximal part of the tibia and the ankle joint.

Aged↗
PubMed2006

Association between rotator cuff abnormalities and reduced acromiohumeral distance.

OBJECTIVE: The purpose of this study was to evaluate the association between rotator cuff abnormalities and reduced acromiohumeral distance. MATERIALS AND METHODS: Acromiohumeral distance was measured on conventional radiographs and on MR images. Three age- and sex-matched patient groups each including 21 patients were stratified according to acromiohumeral distance on conventional radiographs (group 1, 10 mm). Acromiohumeral distance was related to the presence, location, and size of a rotator cuff tear and the degree of fatty degeneration of the muscle assessed on MR arthrography. The relative influence on acromiohumeral distance of the various MR arthrographic findings was assessed. Spearman's rank correlation and stepwise regression were used for statistical analysis. RESULTS: In group 1 (acromiohumeral distance <or= 7 mm) full-thickness supraspinatus tendon tears were present in 90% (19/21) of the patients, infraspinatus tendon tears in 67% (14/21) of the patients, and subscapularis tendon tears in 43% (9/21) of the patients. The size of rotator cuff tendon tears and the degree of fatty degeneration in all rotator cuff muscles showed a significant negative correlation with acromiohumeral distance (p < 0.05). After stepwise regression, a significant relative influence on acromiohumeral distance remained for size of rotator cuff tear (p < 0.0001) and for degree of fatty degeneration of the infraspinatus muscle (p = 0.013). CONCLUSION: Tendon tears and fatty muscle degeneration in the rotator cuff correlate with reduced acromiohumeral distance. Size of rotator cuff tear and degree of fatty degeneration of the infraspinatus muscle have the most pronounced influence on acromiohumeral distance.

Acromion↗
PubMed2003

Correlation of phasic and tonic skin-conductance responses with severity of motion sickness induced by viewing an optokinetic rotating drum.

50 subjects viewed an optokinetic rotating drum for 12 min. Subjective ratings of motion sickness were obtained during the development of motion sickness. The tonic and phasic skin-conductance responses were recorded from the sites of finger, palm, and forehead during the baseline and drum-rotation periods. Analysis showed subjects' subjective ratings of motion sickness gradually increased during the 12 min. of the drum-rotation period. Both phasic and tonic skin conductance also gradually increased during drum rotation for all subjects. Pearson correlations for 50 subjects showed their ratings of motion sickness during the drum-rotation period were significantly correlated with ratios of phasic skin conductance recorded at the forehead between drum rotation and baseline periods (r = .62), followed by ratios of tonic skin conductance recorded at the finger palmar site (r = .48), ratios of phasic skin conductance recorded at the finger palmar site (r = .43), and ratios of tonic skin conductance recorded at the forehead site (r = .39). In conclusion, the phasic skin-conductance responses recorded at the forehead site were most sensitive physiological correlates of motion sickness induced by viewing an optokinetic rotating drum.

Adolescent↗
PubMed1996

Glenohumeral joint internal and external rotation range of motion in elite junior tennis players.

Objective measurement of range of motion of the glenohumeral joint is important for the rehabilitation and prevention of shoulder injury. The primary purpose of this study was to determine whether significant differences exist between the dominant (tennis playing) and nondominant extremity in active internal and external rotation range of motion in elite junior tennis players 11-17 years of age. Two hundred three elite junior tennis players (113 males, 90 females) were bilaterally measured for internal and external rotation at 90 degrees of abduction in a supine position with a specific methodology attempting to isolate glenohumeral motion, while minimizing or negating scapulothoracic motion. A standard universal goniometer was utilized to measure active range of motion (AROM). Dependent t tests were used to compare differences between extremities. No significant difference was found for males or females between the dominant and nondominant arm in external rotation. Analysis of internal rotation (AROM) differences showed significantly less (p < .001) internal rotation (AROM) on the dominant arm for both males and females. Significantly less (p < .001) dominant arm total rotational range of motion was also found in both males and females. The loss of dominant arm internal rotation (AROM) has clinical application for both the development of rehabilitation and preventative flexibility/range of motion programs.

Adolescent↗
PubMed1997

Postoperative eccentric and concentric isokinetic strength for the shoulder rotators in the scapular and neutral planes.

Considerable variability exists for isokinetic testing of the shoulder rotators, leaving the clinician in a quandry concerning the most appropriate method for patient evaluation. The purpose of this study was to evaluate concentric and eccentric rotational strength in the scapular and neutral planes for the surgical and nonsurgical shoulders. Fifteen males consented to be tested during a 90-minute isokinetic session. Both shoulders for each patient were tested concentrically (240 degrees/sec) and eccentrically (120 degrees/sec) in the scapular and neutral planes. Patient positioning was maintained through the use of a goniometer, plumb line, and floor grid system. Following a warmup, five maximal effort reciprocal internal and external rotation concentric and eccentric contractions were evaluated using multiple two-way analyses of variance (shoulder x plane) with repeated measures. Results indicated no statistically significant differences between the surgical or nonsurgical shoulders for either concentric (p = .063-.247) or eccentric (p = .460-.840) modes, regardless of test plane. No statistically significant differences were observed eccentrically between test planes (p = .06-.470), but the scapular plane produced significantly higher (p = .005) peak torques concentrically. Generally, the external rotators were 53.0% (concentrically) and 63.0% (eccentrically) of the internal rotator strength for either shoulder. Clinically, concentric and eccentric testing of the postoperative shoulder patient can occur in either the scapular or the neutral plane. However, the scapular plane may be preferred since it is more functionally relevant and less injurious to the rotator cuff. A full, functional recovery may be expected for the rotator cuff repair patient.

Adult↗
PubMed1977

The maxillary rotation: Its relation to the cranial base and the mandibular corpus. An implant study.

A material of 22 patients with metallic implants was used in a longitudinal study, based on lateral head-plates, of the relationship between: 1) the maxillary rotation and the cranial base 2) the maxillary rotation and the different mandibular rotations. No connection has been found between the variation of the maxillary rotation and the growth of the cranial base. The correlation between the maxillary and the mandibular rotations is the highest when the rotation of the corpus is considered. A strong correlation is found between the variation of the condylar growth direction and the variation of the maxillary rotation.

Adolescent↗
PubMed1991

Test for otolith organs with barbecue rotation.

In the sitting position, vertical axis head rotation stimulates only the horizontal canal. In the supine position, horizontal axis rotation, so-called barbecue rotation, is a stimulus to both the horizontal canal and otolith organs. We compared dynamic otolith response to these two types of harmonic rotations in 15 normal subjects. The subjects' heads were rotated, passively with eyes open but covered, at the following frequencies: 0.17, 0.33, 0.50, 0.67 and 1.00 Hz. Head movement and eye movement were recorded by scleral search coil technique. Compensatory eye movements were present on each record. Vestibulo-ocular reflex (VOR) gain was calculated using peak-to-peak velocity of the eye and head. At all frequencies the VOR gain of horizontal axis rotation was larger than that of vertical axis rotation. This difference was maximal at the lowest frequency, 0.17 Hz, suggesting that dynamic otolith stimulus improves VOR at low frequencies.

Adult↗
PubMed1995

Self-rotation estimate about the vertical axis.

The aim of this paper was to examine the accuracy of passive whole-body self-rotation estimate around the earth-vertical (yaw) axis. Subjects were required to reach an imposed angle of +/- 90 degrees, 180 degrees or 360 degrees (outward way), and then to rotate back to the initial position (return way), through passive rotation controlled by the subject, in darkness. During these rotations, only the semi-circular canals were stimulated. On the outward way, subjects were required to elaborate the correct imposed angle, without any external reference. In average, subjects undershot the expected angles on outward way, which suggests an overestimate of self-rotation, and the error increased with increasing expected angle. On the return way, subjects had to rotate back to the starting point, through a path integration process. There was no effect of the imposed angle on the error, and the variability was lower than on the outward way. The data suggests that the subjects could construct the internal representation of a virtual starting point: the initial body position, which became a goal to reach clearer than the outward rotation angle, which the subjects also have defined, in an environment deprived of any external spatial reference.

Adult↗
PubMed1999

[Treatment of fresh humeral diaphysis fractures by Seidel intramedullary locked nailing. A study of 23 initial cases after 2.5 years with rotator cuff evaluation].

PURPOSE OF THE STUDY: The Seidel intramedullary locking nail is one of the alternative methods for operative treatment of humeral shaft fractures. Short follow-up demonstrated persistent pain and stiffness at the shoulder joint. The aims of this retrospective study were first to evaluate results with attention to operative technique, consolidation rate and postoperative complications. Second we studied rotator cuff healing in our first patients. MATERIAL AND METHODS: Twenty-five acute diaphyseal fractures were treated between May 91 and Dec 94. We reviewed personally 23 patients with a mean follow-up of 33 months (range 22-66). The dominant fracture type according to AO was type A. Clinical shoulder assessment was carried out using the Constant score. Isometric strength was recorded in both shoulders with a hand-held dynamometer in abduction, external and internal rotation. Sonographic evaluation of the rotator cuff was performed using a 7.5 MHz linear array transducer in all 23 patients. RESULTS: All but one fracture healed at an average of two months. Impingement was observed in three patients but pain relief and normal shoulder motion have been reached after nail removal. Infection occurred in one patient but final result was good. Constant score averaged 78.7 (range 51-94.2) classifying the result in all but two patients as excellent or good. Compared with the external and internal rotations, strength was significantly reduced in abduction but reached 83.5 per cent of the opposite shoulder. No statistical differences were found in relation with age, gender and side. Compared with the contralateral shoulder, rotator cuff evaluation with sonography was considered as normal in 18 patients. Calcium deposits of the cuff were noticed in the infected patient. In three cases sonography detected hyperechoic line considered as scar in the supraspinatus tendon without any partial or full-thickness tear. DISCUSSION AND CONCLUSION: A median starting point avoids the avascular area and gives a straight access to the medullary canal. This study demonstrates that using this entry portal and a reliable technique antegrade nailing of the humerus does not compromise rotator cuff healing and shoulder function. Technical errors lead to poor or fair results but despite this learning curve, Seidel nail when operative treatment is indicated, is a good choice. Attention must be paid to patients with clinical history of impingement or rotator cuff tendinopathy.

Adult↗
PubMed2000

[Traumatic development of rotator cuff lesion. Scientific principles and consequences for expert assessment].

The traumatic etiology of rotator cuff lesions is a matter of controversial discussed in legal assessments. Because of the relatively high prevalence of degenerative changes with increasing age, including partial and complete rotator cuff tears, it may be difficult to demonstrate the cause of an acute traumatic rotator cuff tear. This article presents a review of the literature concerning current knowledge of the anatomy, biomechanics and pathogenesis of rotator cuff pathology. According to this, a catalogue of potentially adequate and inadequate trauma mechanisms is proposed. Another focus of this work is in the post-traumatic diagnostic steps following persistent rotator cuff-deficient shoulder function. X-ray, ultrasound, MRI and operative findings in rotator cuff tears underline the criteria for distinguishing between traumatic and degenerative lesions. From a legal point of view (e.g., private accident insurance, workers compensation claims), various minor and major arguments are defined, which could help the expert in judging the cause of post-traumatic rotator cuff deficiency.

Diagnosis, Differential↗
PubMed2000

Three-dimensional clinical measurement of bilateral hip and knee rotations.

This paper reports a technique of using an electromagnetic system to measure three-dimensional bilateral hip and knee joint rotations during walking and of using peak cross-correlation between rotation angles to describe the pattern of rotations. Three-dimensional rotations of thigh and shank during gait were recorded using five receivers of the electromagnetic system synchronised with four foot-switches. Thirteen normal subjects were tested on two separate occasions to examine repeatability of the measurements. The relationship between the rotations was represented as lags at peak cross-correlation. Twelve parameters of the lags at peak cross-correlation were calculated. The analysis showed that the joint rotation could be measured reliably and the cross-correlation analysis provided parameters that were generally suitable for defining characteristics of hip and knee joint rotations during gait.

Biomechanical Phenomena↗
PubMed1997

Dynamics of a microcarrier particle in the simulated microgravity environment of a rotating-wall vessel.

Rotating-wall vessel (RWV), a low-shear, low turbulence microcarrier culture system provides a simulated microgravity environment suitable for 3-dimensional tissue culture. In this paper, the motion of a microcarrier particle in the rotating fluid has been analytically/numerically studied. If the microcarrier is less dense than the surrounding liquid medium, it eventually migrates towards an equilibrium state in the fluid. This state corresponds to a stationary location in the inertial frame of reference or equivalently, a circular orbit about the rotational axis in a rotating frame. If the particle is denser, it may move away indefinitely to reach or collide with the outer wall of the rotating vessel (outer boundary of the rotating fluid). Such a collision may damage the cells and could be undesirable for tissue culture. We have calculated migration times for a denser microcarrier to reach the outer wall of the vessel. Several factors--rotational speed, fluid viscosity, density difference between that of the microcarrier and the fluid, microcarrier radius, and the initial position of the microcarrier--were found to affect this migration time. We have also evaluated the variation of the fluid shear stress on the microcarrier surface. Decreasing the density difference between the microcarrier and the fluid, and decreasing the size of the microcarrier, can both decrease the maximum shear stress. The results for a solid, a hollow, and a hollow-porous microcarrier show that with a denser microcarrier material, the hollow or hollow-porous spherical microcarriers are preferable in order to increase the suspension time and decrease the maximum shear stress. The results of this study are thought to be useful for the development of optimal conditions for cell growth and metabolism in RWVs.

Cell Culture Techniques↗
PubMed2001

The effect of vertebral rotation of the lumbar spine on dual energy X-ray absorptiometry measurements: observational study.

OBJECTIVE: To estimate how axial rotation of lumbar vertebrae quantitatively affects bone mineral density, as measured by dual energy X-ray absorptiometry in the anteroposterior plane. DESIGN: Observational study. SETTING: University teaching hospital, Hong Kong. PATIENTS: Cadaver lumbar vertebrae (L2 to L4) were removed from four adults. MAIN OUTCOME MEASURES: Using dual energy X-ray absorptiometry, the bone mineral content, bone area, and bone mineral density were measured in the neutral position and with vertebral axial rotation in increments of 7.5 degrees, up to a maximum of 45 degrees. RESULTS: Correlation analysis showed a significant positive correlation between the degree of rotation and measured bone area, a significant negative correlation between degree of rotation and bone mineral density measurements, but no significant correlation between degree of rotation and measured bone mineral content. The measured bone area increased approximately 24% and the bone mineral density decreased approximately 19% when the vertebrae were rotated by 45 degrees. CONCLUSIONS: These results suggest that for patients with rotational deformity of the spine, such as scoliosis, measurements of lumbar spine bone mineral content by dual energy X-ray absorptiometry is not affected, while bone mineral density measurements are not reliable.

Absorptiometry, Photon↗
PubMed2002

[Bipolar arthroplasty in rotator cuff arthropathy: 13 cases].

PURPOSE OF THE STUDY: A series of 13 patients with an excentered osteoarthritis of the glenoid who underwent bipolar shoulder arthroplasty is reported. MATERIAL AND METHODS: The series included 13 patients treated in two centers between 1995 and 1998. Mean age was 70 years (58-88). Constant's absolute score and Swanson's score were used for clinical assessment. The Hamada and Fukuda classification was used for the radiographic assessment. The follow-up radiography series included an AP view in the three rotation positions, an AP view in maximum abduction to assess intraprosthetic mobility, a lateral view (Lamy) and measurements of both humeri. Several measurements were made to assess humerus lateralization and glenoid wear: deltoid lever arm, lateral humeral displacement, distance between the lateral border of the coracoid and the center of the glenoid and the subacromial space. Mean preoperative Constant score was 23 points: pain 3 pts, activity 5 pts, motion 13 pts, force 2 pts. Mean preoperative Swanson score was 11. Active anteflexion was 78 degrees, active abduction 68 degrees and passive external rotation 17 degrees. The Hamada and Fukuda classification was 9 grade 4 and 4 grade 5. All patients had a full thickness unrepairable rotator cuff tear: three with 2 tendon tears, and 10 with 3 tendon tears. All patients were reviewed clinically and had a complete radiography series at last follow-up (mean 28 months, range 7 - 56 months). RESULTS: At last follow-up, the mean absolute Constant score was 37 points: pain 10 pts, activity 9 pts, motion 14 pts, force 4 pts. Mean Swanson score at last follow-up was 19 points. Mean active anteflexion was 69 degrees, active abduction was 63 degrees and passive external rotation was 29 degrees. A satisfactory deltoid lever arm had been achieved compensating the glenoid wear by a greater lateral displacement of the humerus. At last follow-up, there were no cases of humeral loosening but three cases with important glenoid wear were observed after two years. Comparing the results obtained using small cups (40 and 44) with arthroplasties using large cups (48 and 52) showed a trend favoring small cups: Constant score 43 vs 32 points, Swanson score 21 versus 17 points, anteflexion 72 degrees versus 66 degrees and passive external rotation 34 degrees versus 26 degrees. DISCUSSION: Our results confirmed the efficacy of bipolar arthroplasty for pain relief, but the mobility outcome was less than satisfactory, excepting passive external rotation. It would appear to be preferable to use small cups. Comparing our results with data in the literature, particularly the better results for mobility using simple humeral prostheses, suggests that the principles of shoulder and hip arthroplasty concern different mechanisms: a sufficient deltoid lever arm must be achieved, but without overstretching the periarticular soft tissue (capsule, subcapsule, teres minor), and using a cup size close to the size of the healthy humeral head. Glenoid reaming should not be reserved only for asymmetrical glenoid wear in the horizontal plane. CONCLUSION: Our results suggest that bipolar arthroplasty for excentered osteoarthritis of the glenoid cavity is indicated for: stiffness in external rotation, major concentric wear in patients under 65 years of age, or asymmetric glenoid wear.

Aged↗
PubMed2006

Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces.

The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.

Ceramics↗
PubMed2006

Correlation of an induced rotation model with the clinical categorisation of scoliotic deformity--a possible platform for prediction of scoliosis progression.

AIM: The primary aims were to develop a simplified three-dimensional model of the thoracolumbar spine and to predict the influence of axial rotation at different levels of the spine on the resultant scoliotic curve, using King's classification as a comparator. MATERIALS AND METHODS: A three-dimensional mathematical model of the simplified thoracolumbar spine (constant size vertebral body without posterior elements) was developed using anatomical data from the published literature. The influence of rotational displacement of the motion segments at various levels of the spine was studied by applying different axial rotations, using a three-dimensional homogeneous transformation matrix method. RESULTS: The result of the model show the correlation of the deformity in lower regions of the spine (lumbar) with the geometrical changes in upper regions of the spine (thoracic), associated with the continuous alteration in direction of the vertebral axis of rotation along the spine. The final curvature of the scoliotic spine is influenced by both the degree of axial rotation in each region and the spatial deformation of the spine (e.g. kyphotic shape and extent of lateral deformity). Qualitatively, the model is capable of producing different categories of the spinal deformity based on King's classification. CONCLUSION: A three-dimensional analysis of spinal shape demonstrates the important relationship between induced vertebral rotation and the resulting deformity. The effect of rotational displacement on the overall configuration of thoracolumbar spine during juvenile growth was assessed and demonstrates close correlation with deformities of the lower regions of spine.

Disease Progression↗