EVALUATION OF TWO KINDS OF SPINAL INTERNAL FIXATION IN CLINICAL RESULTS AND BIOMECHANICS
作者：SHEN Gen-biao(沈根标), LUO Zhuo-jing(罗卓荆), CUI Hai-xiang(崔海相)
单位：Department of Orthopedic Surgery of Tandu Hospital, the Fourth Military Medical University, Xi'an 710038 SHEN Gen-biao(沈根标), LUO Zhuo-jing(罗卓荆), CUI Hai-xiang(崔海相)
关键词：
中华创伤杂志980358 Objective To evaluate two kinds of internal fixation in clinical results and biomechanic test.
Methods Seventy-seven consecutive patients with thoracolumbar spine and spinal cord injuries were treated by two kinds of internal fixators: Seventeen cases of group A were treated by Harrington distraction rod with Luque segmental wires and sixty cases of group B by Edwards device. Biomechanic experimental study was done with swine thoracic and lumbar spine to compare the axial correcting force on anterior longitudinal ligaments between Edwards device and Harrington distraction device.
, 百拇医药
Results The averages of the correction of segmental kyphosis were improved from 22.2 degree of preoperation to 11.8 of postoperation in group B and from 29.3 to 2.6 in group A. The reduction of anterioposterior displacement were improved from 32.3% to 9.7% in group A and from 30.0% to 0.8% in group B. The restoration of the compressed vertibral height were improved from 55.5% to 64.5% in group B and from 50.4% to 97.5% in group A. Neurological function improvement above one Frankel grade was 82% in group B and 90% in group A. The axial correcting forces on anterior longitudinal ligaments applied by Edwards rod-sleeve device were 89.0N, which were 82.7% higher than 48.7%N by Harrington distraction rod in biomechanic experiment.
, 百拇医药
Conclusion The results indicated that the Edwards device was superior to Harrington distraction rods both in clinical practice and biomechanic test.
A retrospective comparison analysis of 77 consecutive patients who underwent treatment with the two different kinds of spinal internal fixation for thoracic and lumbar spinal fractures in our department from 1984 to 1989 was performed. Seventeen cases as group A were treated by Harrington rod with segmental sublaminar wires fixation,1 Sixty cases as group B were treated with Edwards rod-sleeve devices. In addition, biomechanic experimental study was done with swine thoracic and lumbar spine to compare the axial correcting force on anterior longitudinal ligaments between Edwards device and Harrington device.
, http://www.100md.com
MATERIALS AND METHODS
Clinical Evaluation Clinical results were evaluated by four points, the vertebral height, angulation, translation and spinal cord status.
1. Angulation (Kyphosis): Maximum angulation was examined by Cobb measurements on anteroposterior and lateral radiographs preoperatively and postoperatively (in 2 weeks after operation).
2. Translation: Maximum translation (horizontal displacement) was measured as perpendicular distance in millimeters between vertical lines dislocated vertebral bodies preoperatively and postoperatively.
, 百拇医药
3. Vertebral height: Vertebral height was reported as a percentage of normal anterior vertebral body of the average of above and below adjacent vertebral body preoperatively and postoperatively.
4. Neurological status: Neurological status of each cases was observed by Franked method preoperation and postoperation.
Biomechanic Evaluation Biomechanic study was performed on 6 fresh swine thoracic and lumbar spines, which 15 injured specimens were made with anterior and middle columns disrupted and posterior column intact. Force transducer equipped with strain gauge was fixed anteriorly at vertebra spanning the disrupted site.
, 百拇医药
RESULTS
Variable reductions and stable fixations were achieved by the two kinds of internal devices. (Tables 1,2,3).
Table 1 Averages of the correction of seg
preoperation
postoperation
improvement
Group A
22.2
11.8
, http://www.100md.com
10.4
Group B
29.3
2.6
26.7
Table 2 Averages of the reduction of anterioposterior displacement (%)
preoperation
postoperation
improvement
Group A
32.3
, http://www.100md.com
9.7
22.6
Group B
30.0
0.8
29.2
Table 3 Averages of restoration of the compressed vertebral height (%)
preoperation
postoperation
improvement
Group A
, http://www.100md.com
55.5
64.5
9.0
Group B
50.4
97.5
47.5
Neurological function improvement above one Frankel grade was 82% in group A and 90% in group B. The complete spinal cord deficits in group B was 42.6% and 29% in Group A preoperatively.
, http://www.100md.com The axial correcting forces on ALL applied by Edwards rod-sleeve device were 89.0N and 48.7N by Harrington distraction rod in the biomechanic experiment.
DISCUSSION
Anatomic reduction is important in the treatment of thoracic and lumbar spine for two reasons: (1) full correction of vertebral height, alignment, and displacement maximizes restoration of foraminal and canal areas; (2) anatomic alignment preserves normal posture that can reduce the rate of late back pain. In order to achieve anatomic reduction and rigid fixation for spinal fractures, the fixation technique must be able to exert correcting forces in all directions because thoracolumbar spinal injuries are usually due to complex forces.
, 百拇医药
Edwards internal fixator is superior to Harrington device with Luque wires on reduction of spinal fractures in our clinical practice and biomechanical study. First, the rod-sleeve construct corrects post-traumatic kyphosis by producing an extension “moment,”called as “three point mechanics,” to directly oppose the flexion “moment” that causes the deformity. Our biomechanic study result also showed that Edwards device could provide the axial correcting forces on ALL 82.7% more than Harrington rod device.2-4
, http://www.100md.com
Second, the anterior force from the sleeve is directed through the underlying pedicle to push the posteriorly displacement of the vertebral body forward and contributes a extension moment to produce a local hyperlordosis centered under the pair of sleeves which restores the fractured bony fragment and disc from the spinal canal and shift the cord posteriorly, then indirect 奵ompressing operation for the spinal cord is done, which is very beneficial to the recovery of the spinal cord.
, 百拇医药
Third, rod-sleeves also provide lateral corrective force and rotational stability. This corrects any lateral displacement, angulation and rotation by the pairs of rod-sleeve which fill the potential space between the rod and anatomic position of the posterior elements. It has been demonstrated that Edwards device was much more stable than Harrington distraction rod, Harrington compression rod, Luque device and Dunn anterior device under the flexion moment and extension mament, and than Harrington distraction-compression rod, Harrington distraction rod, Harrington compression rod, Dunn device under lateral bending moment and axial rotational moment in Panjabi's biomechanic study.5
, 百拇医药
Lastly, the rod-sleeves method stores elastic within the spinal rods to help overcome anterior ligament stress-relaxation to resist the future collapse and maintain the reduction.
The results from our clinical and biomechanic studies showed that Edwards internal device was superior to Harrington distraction rod with sublaminar wires in the treatment of the thoracic and lumbar spinal injuries.
REFERENCES
, 百拇医药
[1] Shen GB, Chui HX, Hao JJ, et al. Harrington rod and Luque wires in combination with laminectomy for spinal fracture with paralysis. Chinese J Trauma 1987; 3∶75.
[2] Shen GB, Ruan DK, Chui HX, et al. The treatment of thoracolumbar spinal unstable fractures with Edwards rod-sleeve device. Chinese J Spine and Spinal Cord 1991; 1∶33.
[3] Edwards CC, Griffith PH, Murphy J, et al. New techniques in spine stabilization. A scientific exhibit presented at the 49th Annual Meeting, American of Orthopedic Surgeons. New Orlean 1982; 36.
[4] Edwards CC. Early rod-sleeve stabilization of the injured thoracic and lumbar spine. Orthopedic Clinics of North America 1986; 17∶121.
[5] Panjabi MM. Biomechanical evaluation of spinal fixation devices stability provided by eight internal fixation devices. Spine 1988;13∶1135., http://www.100md.com
单位：Department of Orthopedic Surgery of Tandu Hospital, the Fourth Military Medical University, Xi'an 710038 SHEN Gen-biao(沈根标), LUO Zhuo-jing(罗卓荆), CUI Hai-xiang(崔海相)
关键词：
中华创伤杂志980358 Objective To evaluate two kinds of internal fixation in clinical results and biomechanic test.
Methods Seventy-seven consecutive patients with thoracolumbar spine and spinal cord injuries were treated by two kinds of internal fixators: Seventeen cases of group A were treated by Harrington distraction rod with Luque segmental wires and sixty cases of group B by Edwards device. Biomechanic experimental study was done with swine thoracic and lumbar spine to compare the axial correcting force on anterior longitudinal ligaments between Edwards device and Harrington distraction device.
, 百拇医药
Results The averages of the correction of segmental kyphosis were improved from 22.2 degree of preoperation to 11.8 of postoperation in group B and from 29.3 to 2.6 in group A. The reduction of anterioposterior displacement were improved from 32.3% to 9.7% in group A and from 30.0% to 0.8% in group B. The restoration of the compressed vertibral height were improved from 55.5% to 64.5% in group B and from 50.4% to 97.5% in group A. Neurological function improvement above one Frankel grade was 82% in group B and 90% in group A. The axial correcting forces on anterior longitudinal ligaments applied by Edwards rod-sleeve device were 89.0N, which were 82.7% higher than 48.7%N by Harrington distraction rod in biomechanic experiment.
, 百拇医药
Conclusion The results indicated that the Edwards device was superior to Harrington distraction rods both in clinical practice and biomechanic test.
A retrospective comparison analysis of 77 consecutive patients who underwent treatment with the two different kinds of spinal internal fixation for thoracic and lumbar spinal fractures in our department from 1984 to 1989 was performed. Seventeen cases as group A were treated by Harrington rod with segmental sublaminar wires fixation,1 Sixty cases as group B were treated with Edwards rod-sleeve devices. In addition, biomechanic experimental study was done with swine thoracic and lumbar spine to compare the axial correcting force on anterior longitudinal ligaments between Edwards device and Harrington device.
, http://www.100md.com
MATERIALS AND METHODS
Clinical Evaluation Clinical results were evaluated by four points, the vertebral height, angulation, translation and spinal cord status.
1. Angulation (Kyphosis): Maximum angulation was examined by Cobb measurements on anteroposterior and lateral radiographs preoperatively and postoperatively (in 2 weeks after operation).
2. Translation: Maximum translation (horizontal displacement) was measured as perpendicular distance in millimeters between vertical lines dislocated vertebral bodies preoperatively and postoperatively.
, 百拇医药
3. Vertebral height: Vertebral height was reported as a percentage of normal anterior vertebral body of the average of above and below adjacent vertebral body preoperatively and postoperatively.
4. Neurological status: Neurological status of each cases was observed by Franked method preoperation and postoperation.
Biomechanic Evaluation Biomechanic study was performed on 6 fresh swine thoracic and lumbar spines, which 15 injured specimens were made with anterior and middle columns disrupted and posterior column intact. Force transducer equipped with strain gauge was fixed anteriorly at vertebra spanning the disrupted site.
, 百拇医药
RESULTS
Variable reductions and stable fixations were achieved by the two kinds of internal devices. (Tables 1,2,3).
Table 1 Averages of the correction of seg
preoperation
postoperation
improvement
Group A
22.2
11.8
, http://www.100md.com
10.4
Group B
29.3
2.6
26.7
Table 2 Averages of the reduction of anterioposterior displacement (%)
preoperation
postoperation
improvement
Group A
32.3
, http://www.100md.com
9.7
22.6
Group B
30.0
0.8
29.2
Table 3 Averages of restoration of the compressed vertebral height (%)
preoperation
postoperation
improvement
Group A
, http://www.100md.com
55.5
64.5
9.0
Group B
50.4
97.5
47.5
Neurological function improvement above one Frankel grade was 82% in group A and 90% in group B. The complete spinal cord deficits in group B was 42.6% and 29% in Group A preoperatively.
, http://www.100md.com The axial correcting forces on ALL applied by Edwards rod-sleeve device were 89.0N and 48.7N by Harrington distraction rod in the biomechanic experiment.
DISCUSSION
Anatomic reduction is important in the treatment of thoracic and lumbar spine for two reasons: (1) full correction of vertebral height, alignment, and displacement maximizes restoration of foraminal and canal areas; (2) anatomic alignment preserves normal posture that can reduce the rate of late back pain. In order to achieve anatomic reduction and rigid fixation for spinal fractures, the fixation technique must be able to exert correcting forces in all directions because thoracolumbar spinal injuries are usually due to complex forces.
, 百拇医药
Edwards internal fixator is superior to Harrington device with Luque wires on reduction of spinal fractures in our clinical practice and biomechanical study. First, the rod-sleeve construct corrects post-traumatic kyphosis by producing an extension “moment,”called as “three point mechanics,” to directly oppose the flexion “moment” that causes the deformity. Our biomechanic study result also showed that Edwards device could provide the axial correcting forces on ALL 82.7% more than Harrington rod device.2-4
, http://www.100md.com
Second, the anterior force from the sleeve is directed through the underlying pedicle to push the posteriorly displacement of the vertebral body forward and contributes a extension moment to produce a local hyperlordosis centered under the pair of sleeves which restores the fractured bony fragment and disc from the spinal canal and shift the cord posteriorly, then indirect 奵ompressing operation for the spinal cord is done, which is very beneficial to the recovery of the spinal cord.
, 百拇医药
Third, rod-sleeves also provide lateral corrective force and rotational stability. This corrects any lateral displacement, angulation and rotation by the pairs of rod-sleeve which fill the potential space between the rod and anatomic position of the posterior elements. It has been demonstrated that Edwards device was much more stable than Harrington distraction rod, Harrington compression rod, Luque device and Dunn anterior device under the flexion moment and extension mament, and than Harrington distraction-compression rod, Harrington distraction rod, Harrington compression rod, Dunn device under lateral bending moment and axial rotational moment in Panjabi's biomechanic study.5
, 百拇医药
Lastly, the rod-sleeves method stores elastic within the spinal rods to help overcome anterior ligament stress-relaxation to resist the future collapse and maintain the reduction.
The results from our clinical and biomechanic studies showed that Edwards internal device was superior to Harrington distraction rod with sublaminar wires in the treatment of the thoracic and lumbar spinal injuries.
REFERENCES
, 百拇医药
[1] Shen GB, Chui HX, Hao JJ, et al. Harrington rod and Luque wires in combination with laminectomy for spinal fracture with paralysis. Chinese J Trauma 1987; 3∶75.
[2] Shen GB, Ruan DK, Chui HX, et al. The treatment of thoracolumbar spinal unstable fractures with Edwards rod-sleeve device. Chinese J Spine and Spinal Cord 1991; 1∶33.
[3] Edwards CC, Griffith PH, Murphy J, et al. New techniques in spine stabilization. A scientific exhibit presented at the 49th Annual Meeting, American of Orthopedic Surgeons. New Orlean 1982; 36.
[4] Edwards CC. Early rod-sleeve stabilization of the injured thoracic and lumbar spine. Orthopedic Clinics of North America 1986; 17∶121.
[5] Panjabi MM. Biomechanical evaluation of spinal fixation devices stability provided by eight internal fixation devices. Spine 1988;13∶1135., http://www.100md.com