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Biomedical subjects

V J Raso

Publications and source records attributed to V J Raso.

At least 37 records · Page 2Linked to original sources
PubMed2002

Long-term follow-up of surgically treated AIS patients.

The aim of this study was to determine the long-term changes in spine and trunk alignment in patients who have undergone scoliosis surgery. Twenty-three (16F; 7M; at age of surgery 15.7 +/- 4.9 years) patients with adolescent idiopathic scoliosis agreed to participate and had posterior-anterior radiographs and surface topography prior to derotation surgery, within 6 months of surgery, at 2 years post-operatively and 5-10 years (mean follow-up period 6.11 +/- 1.6 years) after surgery. Cobb angles, surface trunk rotations, and cosmetic scores were measured at each visit. A questionnaire assessed back appearance and pain at the 5-10 year follow-up. The results of the questionnaire were compared to 25 patients with idiopathic scoliosis who had recently undergone surgery. A paired two-tailed Student's t-test with p=0.05 was used to compare the deformity between visits. The Cobb angle and cosmetic score improved after surgery while the change in trunk rotation was insignificant (p=0.37). Between the two-year and 5-10 year review, the Cobb angle, cosmetic score, and surface trunk rotation significantly increased. Self-perception of appearance and pain were similar to the control group. Surgical correction of scoliosis is not completely maintained during adulthood although the radiographic and surface deterioration does not appear to be clinically significant.

Adolescent↗
PubMed2001

Pineal transplantation after pinealectomy in young chickens has no effect on the development of scoliosis.

STUDY DESIGN: Three experimental groups and one control group of chickens underwent different surgical procedures to determine the effects of pineal gland transplantation on the development of scoliosis. OBJECTIVE: To determine whether transplantation of the pineal gland to the body wall musculature maintains serum melatonin levels at normal values and prevents the development of scoliosis. SUMMARY OF BACKGROUND DATA: Scoliosis occurs consistently after pinealectomy in young chickens. Many characteristics of this scoliosis are similar to those seen in patients with adolescent idiopathic scoliosis. It is not clear whether the underlying mechanism is dependent on reduced levels of serum melatonin or some other aspect of the extensive surgery. METHODS: Four groups of chickens were selected: normal chickens, pinealectomized chickens, chickens that underwent simple cutting of the pineal stalk, and chickens that underwent transplantation of the pineal gland into the body wall. Development of scoliosis was determined from measurement of the Cobb angle from weekly radiographs. RESULTS: All of the experimental groups showed the same levels of incidence and the same patterns of scoliosis development. Serum melatonin levels were reduced to nearly zero in all the experimental groups for the duration of the experiment. Scoliosis developed in none of the normal chickens. CONCLUSIONS: Neither transplantation of the pineal gland into the body wall musculature nor simple cutting of the pineal stalk was able to maintain normal levels of serum melatonin because both procedures reduced levels to nearly zero. The incidence and pattern of scoliosis development in these groups were the same as those for the pinealectomized group. Reduction of serum melatonin levels remains a prerequisite for scoliosis development in young chickens.

Animals↗
PubMed2001

The critical stage of pinealectomy surgery after which scoliosis is produced in young chickens.

STUDY DESIGN: Stages of the surgical procedure for pinealectomy in chickens were identified. Groups of chickens were selected for each stage. Scoliosis development was identified from radiographs. OBJECTIVES: To determine the critical stage of surgery for pinealectomy after which scoliosis develops in young chickens. SUMMARY OF BACKGROUND DATA: Pinealectomy in young chickens consistently produces scoliosis in young chickens that has many characteristics similar to those seen in patients with adolescent idiopathic scoliosis. The mechanism behind this phenomenon remains unknown. METHODS: Five distinct stages in the pinealectomy surgery were identified. Groups of chickens were selected to undergo surgery to represent these five stages. Scoliosis was determined from weekly radiographs. RESULTS: Cutting the pineal stalk was identified as the critical stage in the surgery after which scoliosis developed. The incidence of scoliosis did not increase after more extensive surgery in which the pineal bulb was removed from the skull. This stage was also correlated with a significant reduction of serum melatonin levels. CONCLUSIONS: Cutting the pineal stalk was identified as the critical stage of pinealectomy surgery after which scoliosis may develop. This stage was also correlated with the significant reduction of average serum melatonin levels. These results allow the focus of attention into the mechanism behind this phenomenon to center on the consequences of cutting the pineal stalk rather than total removal of the pineal gland.

Animals↗
PubMed2000

Etiology of idiopathic scoliosis: current trends in research.

Current population studies characterize idiopathic scoliosis as a single-gene disorder that follows the patterns of mendelian genetics, including variable penetrance and heterogeneity. The role of melatonin and calmodulin in the development of idiopathic scoliosis is likely secondary, with indirect effects on growth mechanisms. Reported abnormalities of connective tissue, skeletal muscle, platelets, the spinal column, and the rib cage are all thought to be secondary to the deformity itself. Although no consistent neurological abnormalities have been identified in patients with idiopathic scoliosis, it is possible that a defect in processing by the central nervous system affects the growing spine. The true etiology of idiopathic scoliosis remains unknown; however, it appears to be multifactorial.

Biomechanical Phenomena↗
PubMed1999

The effects of melatonin therapy on the development of scoliosis after pinealectomy in the chicken.

The mechanism underlying the development of scoliosis after pinealectomy in young chickens is unknown. However, since the main product of the pineal gland is melatonin, melatonin remains an obvious focus in studies designed to discover this mechanism. One confounding factor is that serum melatonin levels are close to zero after pinealectomy but scoliosis does not develop in all chickens that have had this procedure. Therefore, the role of melatonin in the development of scoliosis in chickens after pinealectomy remains controversial. In the current investigation, two pilot studies demonstrated that a physiological therapeutic dose of melatonin (2.5 milligrams per kilogram of body weight) restored the circadian rhythm of melatonin, as measured by serum assay. In the main study, this dose was administered daily starting either immediately after the pinealectomy or two weeks after it, when scoliosis had developed. Scoliosis was assessed on weekly radiographs, and the Cobb angle was determined for all chickens in which scoliosis developed. Overall, scoliosis developed in only 56 percent (fifty) of the eighty-nine chickens that had had a pinealectomy; this rate was consistent throughout all experimental groups. Scoliosis did not develop in any of the control chickens, which did not have a pinealectomy. On the basis of the average Cobb angles in the chickens in which scoliosis had developed, it was determined that neither the prevalence nor the pattern of the scoliosis was affected by the therapy in any of the experimental groups. It was thus concluded that melatonin therapy after pinealectomy in young chickens has no effect on the development or progression of scoliosis. These results raise doubts regarding the role of melatonin in the development of scoliosis after pinealectomy in the young chicken.

Animals↗
PubMed1998

Changes in serum melatonin levels in response to pinealectomy in the chicken and its correlation with development of scoliosis.

STUDY DESIGN: Normal, sham, and groups of chickens subjected to pinealectomy from which serum melatonin levels were measured and correlated with scoliosis development in a period of 5 weeks. OBJECTIVES: To measure serum melatonin levels in chickens subjected to pinealectomy and control chickens and correlate findings with development of scoliosis. SUMMARY OF BACKGROUND DATA: In a previous study by others, scoliosis developed in 100% of chickens subjected to pinealectomy, and serum melatonin levels were found to be reduced. Previous results in a study by the authors showed scoliosis developing in only approximately 55% of chickens that underwent pinealectomy. METHODS: Young chickens were subjected to pinealectomy. Control groups consisted of sham operation and normal groups. Radiographs and blood samples were taken at weekly intervals to monitor scoliosis development and measure serum melatonin levels using radioimmunoassay techniques. RESULTS: Scoliosis developed in only 52% of chickens that underwent pinealectomy, but all had low levels of serum melatonin and no circadian rhythm. The chickens in the two control groups maintained normal serum melatonin levels and rhythms. CONCLUSIONS: Pinealectomy in young chickens reduces serum melatonin levels and eliminates the melatonin circadian rhythm. It can also produce scoliosis, but low levels of serum melatonin are a poor predictor of development of scoliosis.

Animals↗
PubMed1997

A comparison of the innervation characteristics of the lateral spinal ligaments between normal subjects and patients with adolescent idiopathic scoliosis.

Evidence is rapidly accumulating to suggest that general proprioceptive dysfunction might be a major contributing factor in the development of adolescent idiopathic scoliosis (AIS). The innervation of appropriate ligaments which has been shown to be involved in proprioceptive feedback mechanisms, has also been suggested to play a part in this sensory dysfunction. Accordingly, this study compared the innervation characteristics of lateral spinal ligaments from patients with AIS to similar measurements from control subjects. Using an antibody to neurofilament protein, Ruffini corpuscles, small and large nerve bundles, and free nerve endings were identified and their numbers and distribution patterns compared. In the control group, the innervation was found to be symmetrical between left and right sides but was more concentrated in the ventral portion of each ligament. No apparent morphological defect of the innervation was found in the lateral spinal ligaments of the scoliosis patients but the innervation densities of Ruffini corpuscles, single nerve fibres and total neural elements were significantly lower (p<0.01) than those found in normal subjects. These results suggest a possible mechanism for the production of AIS and warrant further study.

Adolescent↗
PubMed1996

Melatonin levels in idiopathic scoliosis. Diurnal and nocturnal serum melatonin levels in girls with adolescent idiopathic scoliosis.

STUDY DESIGN: Matched pairs of adolescent girls were used to compare serum melatonin levels in adolescent patients and control subjects with idiopathic scoliosis during the day and in the middle of the night. OBJECTIVES: To compare serum melatonin levels in patients with adolescent idiopathic scoliosis and matched control subjects during the day and in the middle of the night. SUMMARY OF BACKGROUND DATA: Recent studies using the chick as the animal model have suggested that the pineal gland and its main product, melatonin, might be involved in the cause of scoliosis. There have been no studies of melatonin levels in patients with adolescent idiopathic scoliosis. METHODS: Blood was collected from seven adolescent girls with idiopathic scoliosis and a group of seven age-matched control subjects. Two samples were collected, one in the middle of the day and one in the middle of the night, to examine the diurnal variation of melatonin production. Serum melatonin levels were measured using a radioimmunoassay technique. RESULTS: No significant differences were found in serum melatonin levels between experimental and control groups either during the day, when melatonin levels were low, or during the night, when melatonin levels were high. CONCLUSIONS: Whereas pinealectomy in young chickens leads to reduced melatonin levels and the development of scoliosis, the results of this study suggest that melatonin levels in mature patients who already have severe scoliosis do not differ from healthy subjects. Whether melatonin levels differ in humans between healthy subjects and patients with scoliosis at the time of onset of the disease remains to be seen.

Adolescent↗
PubMed1995

The nature and distribution of the innervation of human supraspinal and interspinal ligaments.

STUDY DESIGN: To use fresh, human supraspinal and interspinal ligaments and document their innervation. OBJECTIVES: To characterize the innervation of the human supraspinal and interspinal ligaments. SUMMARY OF BACKGROUND DATA: The nature and distribution of the innervation of spinal ligaments remains unknown. METHODS: Sections of spinal ligaments were labeled with a fluorescent antibody against neurofilament proteins and observed with a confocal microscope. RESULTS: The ligaments were found to be well innervated. Innervation was equally distributed along the ligament, symmetrically distributed between left and right sides, and more densely distributed in the periphery. Pacinian corpuscles were scattered randomly, close to blood vessels, whereas Ruffini corpuscles were in the periphery, close to the collagen bundles. CONCLUSIONS: Human supraspinal and interspinal ligaments are well innervated. This innervation might form the basis of neurologic feedback mechanisms for the protection and stability of the spine. These mechanisms might also be important in the development of diseases such as scoliosis.

Adult↗
PubMed1995

A comparison of spinal ligaments--differences between bipeds and quadrupeds.

Following dissection, the spinal ligaments were observed in a selection of bipedal, pseudobipedal and quadrupedal animals during a search for an appropriate animal model for investigating the innervation of these ligaments. Midline spinal ligaments were found in all animals while lateral spinal ligaments could only be observed in bipedal (human) and pseudobipedal (avian) species. The presence of lateral spinal ligaments in these animals and their absence in quadrupeds suggests that the development of the lateral ligaments reflects a mechanical challenge unique to the erect spine and that these lateral spinal ligaments are fundamental to the stability of an erect posture.

Animals↗
PubMed1993

Effect of varying angles on the pullout strength of interference screw fixation.

Arthroscopically assisted reconstruction of the anterior cruciate ligament-deficient knee using a bone-patellar tendon-bone graft is a new and evolving technique. One technically demanding aspect involves the placement under arthroscopic visualization of the femoral interference screw. The effect on pullout strength of changing the angle of the interference screw from 0 degree to 10 degrees, 20 degrees, or 30 degrees with respect to the bone plug was examined. The mean pullout strengths were 621 +/- 82, 594 +/- 48, 508 +/- 66, and 485 +/- 62 N, respectively. We concluded that there was no significant difference in the tensile strength provided by interference screw fixation for angles up to 10 degrees, but that there was a significant (p = 0.0010) weakening of fixation for screw angles > or = 20 degrees.

Animals↗
PubMed1992

A video digitizer for analysis of trunk deformity in scoliosis.

Scoliosis is a deformity characterized by lateral curvature of the spine and accompanied by axial rotation of the vertebrae; it often causes varying degrees of trunk deformity. Research has indicated that topographic techniques can be used to describe the disorder and monitor its progression. A video image acquisition system has been designed which reduces the time required to quantify topographic details of the trunk and aids in the diagnosis, monitoring and research of scoliosis. This system integrates the capability of large, expensive grey-scale image acquisition equipment into a small, low-cost diagnostic imaging tool using current technologies and design techniques. The video digitizer accepts a standard NTSC monochromatic video signal as input and the unit is connected to a computer via an IEEE-488 bus from which the ditigizer is controlled. The digitizer samples the video signal in real time using a high-speed flash converter controlled by an application-specific integrated circuit; the digital samples are stored in memory until the host computer requests that the information be transferred.

Adolescent↗
PubMed1992

A reproducible porcine vertebral fracture for biomechanical testing of spinal fixation devices.

To evaluate vertebral fracture fixation devices in the laboratory, it is necessary to produce identical and unstable fractures either in anatomic specimen or animal models. Consistent achievement of this goal has not been reported in the literature. This report presents a technique for the study of reproducibility for a particular vertebral fracture model. A precise anterior defect was created in a vertebra of each specimen drawn from a homogeneous population of mature sow spines. The spines were loaded to failure. Fracture reproducibility was shown by measurement of load and displacement, and confirmed by roentgenographic evaluation. The technique is easily applied to human specimens. Because there is a plethora of fracture fixation devices based on hooks, wires, or, more recently, plates and pedicle screws, the reliability of comparative testing of these devices in the laboratory requires an appropriate and reproducible fracture.

Animals↗
PubMed1991

Vibratory response in adolescents who have idiopathic scoliosis.

The PVD Bio-Thesiometer was tested as a tool for measuring vibratory thresholds and for detecting possible differences in these thresholds between adolescents who have idiopathic scoliosis and those who do not. It was found to be limited by low reliability and large errors in measurement, with the metatarsophalangeal joint being the only reliable site for measurement. The vibratory thresholds at this site were significantly higher in the fourteen subjects who had scoliosis than in the twenty-two control subjects. No significant asymmetry in vibratory thresholds was found between the concave and convex or the right and left sides in either the scoliotic or the control group. Because there was no significant difference between the readings from the concave and convex sides, it is unlikely that a lesion of the posterior column is responsible for idiopathic scoliosis. If there is a difference, then the PVD Bio-Thesiometer is not sufficiently reliable to detect it.

Adolescent↗
PubMed1990

Vertebral end-plate failure in porcine and bovine models of spinal fracture instrumentation.

The use of mature porcine and immature bovine spines as models for the assessment of spinal fracture instrumentation is commonplace. By comparing the load-displacement characteristics of these spine segments and observing the fracture type, this study investigated the tendency of immature bovine spines to fail prematurely at the vertebral physis, disrupting biomechanical evaluation of spinal fracture fixation devices. Load to failure of the spines was determined using the Instron Universal Testing Machine and a specially designed endcap. In axial compression, the 10-16-week-old calf spines failed at 12,845 +/- 1,466 N, compared with mature pig spines at 17,300 +/- 5,170 N (p less than 0.05). Axial compression with flexion caused consistent failure through an end-plate in both species: 995 +/- 156 N for the calf spines and 2,025 +/- 575 N for the porcine spines (p less than 0.005). It was concluded that the tendency for immature bovine spines to fail more readily at the cartilaginous end-plate makes the calf spine a less desirable model.

Aging↗
PubMed1990

End-cap for the biomechanical testing of spinal segments.

Precise mechanical loading is essential in the in vitro evaluation of spinal fixation instrumentation, but the control of experimental variables is difficult because of variations in specimen morphology, size and end conditions, and gross specimen flexibility. This paper describes an end-cap which is simple in design, time efficient in its attachment to the spine and which provides precise positioning and rigid control of the end fixation points, resulting in excellent experimental control. It is easily adapted to human or animal specimens and provides a reliable load application unit, which permits specific physiological end conditions to be applied.

Animals↗
PubMed1990

A comparison of four computerized methods for measuring vertebral rotation.

The ability to measure vertebral rotation is particularly important in the assessment and treatment of scoliosis. We determined the accuracy and precision of four methods that may be used with routine anteroposterior (AP) spine radiographs. Two vertebrae were radiographed at 0 degrees and at 5 degrees intervals to 20 degrees and at 30 degrees, to the right and left. The radiographs were distributed to three members of the staff who marked the 14 points required for calculating rotation with the four methods. The points were digitized, and rotation calculated by computer. The results showed no significant difference in the calculated rotation of the two vertebrae, or between the results of the three markers. Stokes's method was significantly the least accurate. The other three methods were not significantly different but Bunnell's method appeared to give more consistent results.

Diagnosis, Computer-Assisted↗