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J J Crisco

Publications and source records attributed to J J Crisco.

54 records · Page 3Linked to original sources
PubMed1991

Three-dimensional translational movements of the upper cervical spine.

In 10 fresh cadaveric specimens of occiput (C0) to C3, six pure moments (maximum 1.5 Nm) were applied and the resulting physiological motions were studied. We determined the quantitative three-dimensional relative translations of two specific midsagittal points on C0 and C1: the anterior (point A) and posterior (point B) margins of the foramen magnum of C0, and the posteroinferior margin of anterior arch (point C) and the anteroinferior margin of posterior arch (point D) of C1. In flexion/extension, translational movements of these four points were mainly in the sagittal plane. In axial torque and lateral bending moment, both points on C0 shifted laterally, to the same side of axial torque and to the opposite side of lateral bending. The pattern of the translation of C1 in left axial torque was similar to that in the right lateral bending moment, although the magnitude was larger in the former. In these situations, point C moved to the left, and point D moved to the right and anterior. The vertical translation had two phases: superior translational phase, followed by inferior translational phase. We presented the quantitative translations but, because of large standard deviations between the specimens, it was difficult to define translational thresholds for instability.

Adult↗
PubMed1991

The intersegmental and multisegmental muscles of the lumbar spine. A biomechanical model comparing lateral stabilizing potential.

The intersegmental and multisegmental musculature of the lumbar spine was studied in a biomechanical model to compare their lateral stabilizing potential. By approximating the active and passive behavior of the stretch reflex as a variable stiffness spring whose stiffness was proportional to activation, the critical muscle stiffness required for mechanical stability was calculated. The model demonstrated that the intersegmental muscles were the least efficient at laterally stabilizing the spine. At any given load, multisegmental muscles were more efficient, and their efficiency increased with the number of segments spanned. The most efficient muscles were those that originated from the pelvis, spanning the maximum number of segments. The muscular model was unstable, regardless of the muscular stiffness, when any vertebral segment was devoid of muscle. Moreover, when the load on the spine is increased, buckling can be prevented most efficiently with the pelvic muscles and least efficiently with the intersegmental muscles.

Anatomy↗
PubMed1991

Experimental study of atlas injuries. I. Biomechanical analysis of their mechanisms and fracture patterns.

Understanding injury mechanisms is important for the prevention, diagnosis, and treatment of spinal injuries. Using 10 fresh cadaveric human spine specimens of occiput to C3, clinically similar injuries of the atlas (C1) were produced with high-speed (4.4 m/sec) axial compression. The traumatic event was biomechanically monitored. The resulting injuries were studied with radiography, computed tomography, and a multidirectional instability test. The average compressive failure force was 3,050 N for specimens impacted in neutral posture (n = 437) and 2,100 N for those in extended posture (n = 282). Corresponding values for the impulse were 34.9 Nsec (n = 8.3) and 17.6 Nsec (n = 1.8). Average instability for both groups, as measured by the neutral zone and range of motion, increased by 90% and 44%, respectively, in flexion-extension and 20% in lateral bending, but not in axial rotation. These findings confirm the clinical observations.

Biomechanical Phenomena↗
PubMed1991

Experimental study of atlas injuries. II. Relevance to clinical diagnosis and treatment.

Atlas injuries were produced in vitro and evaluated by radiographic examinations and anatomic studies from a clinical viewpoint. Ten cadaveric human upper cervical spine specimens were subjected to a high-speed axial impact. Injuries to the atlas consisted of six bursting fractures, two ruptures of the transverse ligament, one four-part fracture without a prominent bursting, and one posterior arch fracture. The major soft tissue injury involved the transverse ligament. There were five bony avulsions and three midsubstance tears. In this study, computed tomographic examinations clearly demonstrated the sites of fracture and bony avulsions of the transverse ligament. The best diagnostic tool for function of the transverse ligament was determined to be the atlantodental interval on flexion radiographs. Axial traction force reduced a bursting fracture of the atlas ring. The in vitro atlas injury model gives useful information for clinical diagnosis and treatment.

Biomechanical Phenomena↗
PubMed1991

Transections of the C1-C2 joint capsular ligaments in the cadaveric spine.

The purpose of this study was to examine the mechanical function of the C1-C2 capsular ligaments. Physiologic torques of up to 1.5 Nm were applied to human fresh cadaveric specimens (C0-C1-C2-C3) in three dimensions, and the three-dimensional motion of C1 relative to C2 was recorded. Two groups of cadaveric specimens were used to study the effect of two different sequential ligamentous transections. In the first group (n = 4), the transection of the left capsular ligament was followed by transection of the right capsular ligament. In the second group (n = 10), the transection of the left capsular ligament was preceded by transection of the left and right alar and transverse ligaments. The greatest changes in motion occurred in axial rotation to the side opposite the transection. In the first group, left capsular transections resulted in a significant increase in axial rotation range of motion to the right of 1 degree. After the right capsular ligament was transected, there was a further significant increase of 1.8 degrees to the left and 1.0 degree to the right. Lateral bending to the left also increased significantly by 1.5 degrees after both ligaments were cut. In the second group, with the nonfunctional alar and transverse ligaments, transection of the left capsular ligament resulted in greater increases in range of motion: 3.3 degrees to the right and 1.3 degrees to the left. Lateral bending to the right also increased significantly by 4.2 degrees.

Cadaver↗
PubMed1990

The role of the iliolumbar ligament in the lumbosacral junction.

The biomechanical function of the iliolumbar ligament in the human lumbosacral junction was investigated by analyzing the three-dimensional movements of the whole lumbar and lumbo-sacral-ilium specimens. The experiment was repeated in the following three conditions: 1) intact iliolumbar ligament, 2) right iliolumbar ligament transected, and 3) bilateral iliolumbar ligaments transected. The representative values of the increased motions, compared with intact, after transection of the bilateral iliolumbar ligaments were 1.7 degrees (23%) in flexion, 1.1 degrees (20%) in extension, 0.3 degrees (18%) in axial rotation, and 1.2 degrees (29%) in lateral bending. The most restricted motion governed by the iliolumbar ligament in the lumbosacral junction was lateral bending. The bilateral iliolumbar ligament specimen could restrict flexion and extension of the lumbosacral junction, but the unilateral iliolumbar ligament preparation alone could not restrict these motions. The iliolumbar ligament also had the function of restricting the rotational movement of the lumbosacral junction.

Adult↗
PubMed1990

Biomechanical evaluation of lumbar spinal stability after graded facetectomies.

In an in vitro experiment using fresh human lumbar functional spinal units, the effects of the division of the posterior ligaments (consisting of the supraspinous/interspinous ligaments) and graded facetectomies were investigated. The graded facetectomies consisted of unilateral and bilateral medial facetectomies, and unilateral and bilateral total facetectomies. Six kinds of moments were applied and ranges of motion (ROM) and neutral zones (NZ) were determined three-dimensionally by stereophotogrammetric methods. Range of motion was not affected by the division of the supraspinous/interspinous ligaments for all load modes. In flexion, ROM increased slightly after unilateral medial facetectomy. In right axial rotation, ROM increased after left unilateral total facetectomy. Range of motion was not affected, even by bilateral total facetectomies, in extension and lateral bendings. This study suggested that medial facetectomy does not affect lumbar spinal stability, and conversely, total facetectomy, even created unilaterally, makes the lumbar spine unstable.

Biomechanical Phenomena↗
PubMed1990

Functional stability of the canine cervical spine after injury. A three-month in vivo study.

Although clinical instability is an in vivo problem, most spinal instability criteria are either subjective or are based on in vitro experiments. The authors performed an in vivo experiment using a canine model to study the natural history of spinal instability as a function of healing time up to 12 weeks. Three injuries were produced surgically: sham; laminectomy at C4; and bilateral facetectomy at C4-C5. Three 1.5-mm steel balls were implanted into C3 to C6 vertebrae at the time of surgery. Standardized functional flexion-extension stereoradiographs of the cervical spine were obtained before injury, immediately after injury and at 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7.5, 9, and 12 weeks postinjury and immediately after killing the animals. In general, the authors found decreased ranges of motion (ROM) at the C4-C5 level, compared with the pre-injury values, for all injuries, but most significantly for the facetectomy. The maximum decrease occurred between 0 and 0.5 weeks postinjury. Between 2 and 12 weeks, there was recovery in the ROM, especially for the two less severe injuries. The changes in the ROM at each spinal level were explained by simultaneous presence of a destabilizing factor, caused by the three different injuries with the sham as the least and the facetectomy as the most destabilizing injury, and a stabilizing mechanism of muscle spasm in the beginning and of healing and other adaptive responses in the late phase after injury. Because of the significant differences between the canine model and the human cervical spine, the present findings should be extrapolated to the human situation with caution.

Animals↗
PubMed1990

The injured canine cervical spine after six months of healing. An in vitro three-dimensional study.

The cervical spine is a common site of spinal injuries. The stability of an injured cervical spine is not only dependent on injury severity, but also on the degree of healing time. Using a canine model, three injuries of varying degrees of severity were surgically produced at the C4-C5 level and allowed to heal for 6 months. No internal or external support was provided. The harvested cervical spines (C2-C7) were subjected to three-dimensional biomechanical testing by applying individually six pure moments. The resulting three-dimensional displacements were recorded using stereophotogrammetry, and the intervertebral motions were calculated. The results are compared with the in vivo behavior of the same specimens and with an in vitro control group. At 1 N-m, the average flexion-extension range of motion (ROM) for the intact C4-C5 level was 24.5 degrees (standard deviation [SD], 6.6 degrees). A facetectomy at this level significantly increased the in vitro ROM to 51.1 degrees (SD, 4.4 degrees). The in vitro ROM decreased to 19.8 degrees (SD, 7.3 degrees) in the facetectomized group of this study, which were allowed to heal for 6 months before death. Similar results were obtained in axial rotation and lateral bending. The findings show that after 6 months of healing, the injured canine spine, although acutely hypermobile, exhibited biomechanical characteristics that were not different from those of the normal intact specimens.

Animals↗
PubMed1988

Biomechanics of healing of posterior cervical spinal injuries in a canine model.

The authors performed an in vivo experiment in a canine model to study the natural history of spinal stability as a function of healing time post-injury. Three injuries, in addition to sham, were investigated: 1) transection of supra- and interspinous ligaments at C4-C5; 2) laminectomy at C4; and 3) bilateral facetectomy at C4-C5. Standardized functional flexion/extension stereo-radiographs of the cervical spine were obtained before injury and at 1, 3, 6, 9, 12, and 24 weeks postinjury. The authors found decreased ranges of motion (ROM) at the C4-C5 level for all injuries, including the sham. The decreases, in general, seemed to be in direct proportion to the severity of the injury. When the ROM were normalized to that of the sham at each time point, the relative ROM at C4-C5 increased for Injury 1, remained the same for Injury 2, and decreased for Injury 3. The relative ROM remained the same or increased at C3-C4, and increased at C5-6 for all injuries. It should be emphasized that care should be taken in extrapolating any data from this animal study to the human cervical spine.

Animals↗
PubMed1988

Biomechanical evaluation of spinal fixation devices: II. Stability provided by eight internal fixation devices.

The three-dimensional stability provided by eight spinal fixation devices has been studied in an in vitro biomechanical model using seven-vertebrae (T9-L3) fresh cadaveric thoracolumbar specimens. An injury was created at T12-L1 by complete transection of the posterior elements and posterior half of the intervertebral disc, leaving the anterior half of the intervertebral disc and anterior longitudinal ligament intact. The three-dimensional rotational and translational motions, measures of biomechanical instabilities, were determined under physiologic loads for the intact specimen after injury and instrumentation with each of the eight fixation devices. The tested devices were: Dunn's anterior device (DD); Harrington distraction (HD); Harrington compression (HC); Harrington distraction-compression combination (HDC); Harrington distraction with sleeves (HDS); Luque rods (LQ); Luque rectangle (LR); and Luque short rectangle (LSR). The following devices were stable under the four loads: Flexion: HC, HD, HDC, HDS, LQ, and LR; Extension: HD, HDC, HDS, LQ, and LR; Lateral Bending: LQ and LR; and Axial Rotation: none.

Biomechanical Phenomena↗
PubMed1988

Cognitive processing of children with Williams syndrome.

The Illinois Test of Psycholinguistic Abilities was administered to 22 children with Williams syndrome and to 22 children with non-specific development disabilities, matched for age, sex and global intelligence. Visual processing abilities significantly differentiated the two groups. The children with Williams syndrome had substantially more problems with visual reception, visual closure and visual memory tasks. They appeared to adhere more rigidly than controls to a global deployment of visual attention. Their visual processing difficulties were not related to the level of mental ability. Visual reception, closure and memory scores correctly classified 82 per cent of the children with Williams syndrome and 68 per cent of the controls. Instructional and remedial programs are needed for these children.

Aortic Valve Stenosis↗
PubMed1988

Psychologic and neurologic function following treatment for childhood temporal lobe astrocytoma.

Seven school-aged children treated for temporal lobe astrocytomas with surgical resection and irradiation were prospectively tested to evaluate their intellectual, academic, personality, and neurologic status after therapy. At their most recent follow-up examination, neuropsychologic functioning was adequate in only two patients. The other five children manifested either intellectual deterioration, learning disability, mental retardation, or psychopathology. These deficits were associated with poor postoperative performance status, inadequate seizure control, tumor recurrence, and younger age at diagnosis. No pattern of intellectual, academic, or personality dysfunction emerged in association with left- versus right-hemisphere tumors.

Achievement↗
PubMed1983

Quality of life in children treated for brain tumors. Intellectual, emotional, and academic function.

Thirty children with primary brain tumors were evaluated for alterations in intellectual, emotional, and academic functions. Nine were studied following surgery (prior to irradiation) and 21 after postoperative irradiation. Twenty-four patients (80%) showed no serious disabilities on routine medical and neurological examinations. Nineteen patients (63%) had normal intelligence quotient (IQ) levels. Qualitative disabilities on routine examinations were observed in six children: two of nine tested postoperatively, one of six tested after posterior fossa irradiation, and three of 15 tested after cranial irradiation. Subnormal IQ levels were also noted in two of nine children tested prior to irradiation and one of six after posterior fossa irradiation. Of the 15 studied after cranial irradiation, eight had subnormal IQ scores. Serial postirradiation testing in 10 patients revealed improvement in two, stability in five, and further deterioration in three. Ten children were placed in learning disability settings due to achievement delays or problems with selective attending. Social-emotional evaluations detected excessive tendencies toward psychotic symptomatology. Potential etiological factors, including primary tumor site, extent of irradiation, age, and increased intracranial pressure, are discussed. Preliminary findings suggest a greater than normal risk for late neuropsychological alterations among children with supratentorial tumors and/or cranial irradiation.

Achievement↗
PubMedDate not supplied

A muscle contusion injury model. Biomechanics, physiology, and histology.

We developed a reproducible muscle contusion injury and studied its effect on contractile function, histology, and passive failure. An instrumented drop-mass technique (mass, 171 g; height, 102 cm; spherical radius, 6.4 mm) delivered a single impact to the posterior surface of the gastrocnemius muscle in one limb of 40 male Wistar rats. On Day 0, the impact significantly (N = 12, P < 0.01) decreased maximum tetanic tension to 63% of the contralateral control value. Histologic examination demonstrated extravasation of erythrocytes, edema, myofiber disruption, and vacuolation of myofibers. Passive failure initiated at the site of injury. At 2 days, tetanic tension was 75% of controls (N = 11, P < 0.01). Histologically, acute inflammation and phagocytosis were noted. Tetanic tension at 7 days was 81% of controls (N = 8, P < 0.01). Vimentin staining indicated a dramatic increase in myoblast activity. Contractile strength was near normal at 24 days. Histologic examination showed complete regeneration of normal striated muscle fibers. No vimentin activity was found. No passive failures initiated at the injury site. Contusion injury produced a significant deficit in contractile function that continually diminished with gross histologic evidence of degeneration, regeneration, and normalization at the injured muscle fibers.

Animals↗
PubMedDate not supplied

The effect of wrist guards on bone strain in the distal forearm.

There are increasing epidemiologic and biomechanical data suggesting that wrist guards are effective in preventing wrist injuries in snowboarders and in-line skaters. However, there have been few studies designed to determine how they function. In this study we explored the load-sharing function of wrist guards at subfailure loading levels. To do so, we measured bone strain in the distal radius, distal ulna, and midshaft of the radius in cadaveric forearms with and without two types of commercially available wrist guards. We also measured construct stiffness and energy absorption during testing. Our most significant findings were that dorsal and volar distal radius bone strain were reduced with both wrist guards, and wrist guards increased energy absorption. We also found a reduction in dorsal distal ulnar bone strain, but only with the one guard in which the volar plate was elevated off the heel of the hand. In our loading configuration, wrist guards did not increase bone strain at the radial midshaft. These findings provide insight into how wrist guards protect the wrist: during low-energy falls they function partly by load-sharing, as well as by absorbing impact energy.

Aged↗