Biomedical subjects

J Crisco

Publications and source records attributed to J Crisco.

5 recordsLinked to original sources

PubMed1994

[The unstable spine--an "in vitro" and "in vivo study" on better understanding of clinical instability].

In cases of suspected painful instability of a cervical segment, temporary external fixation by means of external fixator was applied. The segmental immobilization caused immediate relief of pain. The pain reoccurred after removal of the immobilization. The effect of immobilization by external fixation was investigated in biomechanical tests using fresh cadaveric C4-7 specimens. Multidirectional flexibility was measured before and after application of the fixator at C4/C5, C5/C6 and C4-6. We measured the reduction in motion between the different segments. In every situation the neutral zone decreased more than the range of motion. The findings are helpful to understand the clinical instability of the spine and support the hypothesis that the neutral zone is more closely associated with clinical instability than range of motion. The combination of clinical application and biomechanical investigation allowed us to establish a direct correlation between instability and pain.

Accidents, Traffic↗

PubMed1991

Flexion, extension, and lateral bending of the upper cervical spine in response to alar ligament transections.

The purpose of this in vitro experimental study was to determine the role of alar ligaments in providing flexion, extension, and lateral bending stability to the upper cervical spine. Ten fresh human cadaver specimens occiput-C3 were studied in a complete unconstrained and three-dimensional manner, first intact and then after sequential cutting of the left and right alar ligaments. At the C0-C1 joint, there were increases in flexion motion with sequential cutting of the alar ligaments but none in extension. For the same joint, cutting of the left alar ligament resulted in a significant increase in neutral zone in right lateral bending but not in left lateral bending, whereas there were no significant increases in the ranges of motion. At the C1-C2 joint, there were significant increases both in flexion and extension due to cutting of the left alar ligament, but subsequent cutting of the right alar ligament resulted in a small increase for flexion only. At this joint, right lateral bending increased due to cutting of the left alar ligament, but the same was not true for the left lateral bending. Subsequent cutting of the right alar ligament resulted in significant increases for both the right and left lateral bending.

Adult↗

PubMed1991

[Instability in injury of the alar ligament. A biomechanical model].

Fresh human cadaveric specimens of occiput (C0) to C3 were subjected to 1.5 nm of flexion, extension and bilateral bending and axial torque. The resulting physiological motions were studied in an unconstrained three-dimensional manner. The effects of sequential transections of the left and right alar ligaments on the relative motion of C0-1 and C1-2 were studied. After transection of the left alar ligament, the percentage increases in neutral zones (NZ) and ranges of motion (ROM) were documented at both the C0-1 and C1-2 joints. In the sagittal plane, the most increase was at C1-2 due to the flexion moment, e.g., 47.4% in NZ and 27.6% in ROM. In lateral bending, the left alar transsection resulted in mostly right lateral bending increases and at the C0-1 joint, 37.1% in NZ and 19.6% in ROM. In axial rotation, changes in the total motion of the C0-2 joint complex were more reliable indicators. For left alar transsection, most increases were in right axial rotation, e.g., 25.6% for right rotation versus 11.2% for left rotation in the NZ parameter. Functional loss of the alar ligaments indicates a potential for instability which, however, must be determined in conjunction with other clinical findings, such as neurological dysfunction, pain and deformity.

Adult↗

PubMed1990

Treatment of meningeal relapse in childhood acute lymphoblastic leukemia: II. A prospective study of intellectual loss specific to CNS relapse and therapy.

Changes in intellectual function during the course of treatment for acute lymphocytic leukemia were studied. Twenty-four children had baseline psychological evaluations and annual reevaluations for 3-6 years postdiagnosis. Treatment in all patients included combination chemotherapy, 2,400 cGy prophylactic cranial irradiation, and intrathecal methotrexate. Central Nervous System (CNS) relapse occurred in eight of these children. It was then treated with 3,000 cGy cranial plus 1,800 cGy spinal irradiation. Patients who remained in continuous complete remission showed no decline in global intelligence quotient (IQ). Patients who experienced CNS relapse had a mean decline of 16 IQ points by 3 years postdiagnosis and the long-term survivors displayed a mean loss of 25 IQ points 5-6 years postdiagnosis. Three of the five long-term survivors of CNS relapse function within the retarded range of mental ability and require special education. The other two have learning problems and display poor academic performance relative to same-age peers. There was no association noted between age at diagnosis and ultimate loss of IQ points. This prospective study suggests that children who receive a second course of cranial irradiation for treatment of CNS relapse are at high risk for significant and progressive intellectual loss.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1989

How does posture affect coupling in the lumbar spine?

There is evidence to suggest that abnormal coupling patterns in the lumbar spine may be an indicator of low-back problems. To quantify the normal coupling patterns, fresh cadaveric human lumbar spine specimens (L1-S1) were used. A pure axial torque or lateral bending moment of 10 N-m (in five equal steps) was applied to the specimen, in five spinal postures, and three-dimensional motions were measured at the five vertebral levels. The results indicated that the coupling patterns changed significantly with the intervertebral level. For example, in neutral posture, the left axial torque produced coupled lateral bending, which varied from approximately 2 degrees right lateral bending at L1-2, to approximately 0 degrees at L3-4, and to approximately 2.5 degrees left lateral bending at L5-S1. Additionally, there was coupled flexion of approximately 1 degrees to 2 degrees at all levels. Application of left lateral bending moment resulted in approximately 1.7 degrees of coupled right axial rotation at all levels, except at L1-L2, where it was 0 degrees. Additionally, there was coupled flexion of 0.7 degrees to 2 degrees at all levels. For example, at the L2-3 level, the left axial torque produced coupled right lateral bending that ranged from approximately 0.5 degrees at full extension to approximately 2.5 degrees at full flexion. There was also accompanying coupled flexion of approximately 0.4 degrees to 1.7 degrees. Application of left lateral bending moment at the L2-3 level produced axial rotation of approximately 2.5 degrees, which did not vary with the posture, while the other coupled motion varied from approximately 1.7 degrees flexion at full extension posture to approximately 0.8 degrees extension at full flexion posture.

Biomechanical Phenomena↗