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Biomedical subjects

R R Jacobs

Publications and source records attributed to R R Jacobs.

At least 55 records · Page 3Linked to original sources
PubMed1984

Surgical management of thoracolumbar spinal injuries. General principles and controversial considerations.

Based on a review of the literature and experience with over 100 surgically treated thoracolumbar spinal injuries, the following information summarizes present knowledge of the subject. Reduction and internal fixation of the injured spine allows early mobilization of all patients, regardless of neurologic deficit, while protecting the neurologic structures from further injury and enhancing their recovery. The ability of the posterior ligamentous complex and the anterior bony column to withstand physiologic loads must be assessed by the history, physical examination, and radiography; then the injured structures should be protected from load or their function replaced by an appropriate surgical implant. Maximum neurologic recovery can be expected with prompt and complete decompression by reduction of the deformity, restoration of the spinal canal, and rigid internal fixation. The internal fixation system selected must provide compression for posterior injuries and distraction for anterior injuries, resist bending in combined injuries, and always restore normal spine shape. The rod-long, fuse-short technique provides the advantages of a more accurate reduction and a more secure fixation, and the minimum length of the fused region results in a more normal spine. The advantages of prompt and rigid but temporary internal fixation justify the risks both short- and long-term.

Adult↗
PubMed1984

A locking hook spinal rod system for stabilization of fracture-dislocations and correction of deformities of the dorsolumbar spine. A biomechanic evaluation.

Existing internal fixation systems for the injured or deformed spine present problems with overdistraction and control of the contoured rod necessary for transverse forces. A locking hook spinal rod avoids these problems by using a locking cover to secure the lamina in the hook and meshing radial grooves to lock the contoured rod to both the upper and lower hooks in 6 degrees intervals of rotation. The 7-mm stainless-steel rod is 50% stronger than the 1/4-in Harrington rod and also avoids the weakening effect of the notches. Cadaver spine testing gives nearly a threefold increase in failure strength (125 +/- 17 Nm versus 44.1 +/- 2.1).

Adult↗
PubMed1984

The effect of internal fixation without arthrodesis on human facet joint cartilage.

Internal fixation of the spine combined with limited or no fusion has been advocated in the treatment of thoracolumbar fractures, spondylolisthesis, and severe juvenile spinal deformities. Internal fixation without arthrodesis of canine facet joints has been shown to result in the irreversible gross and histologic findings typical of osteoarthritis. Surgery was performed in eight patients for the treatment of thoracolumbar fractures. In each patient, Harrington distraction instrumentation was placed across at least two vertebral segments above and below the fused area. Instrumentation was removed six to 26 months following the initial surgery. A unilateral partial facetectomy was performed at the facet joint above the lower Harrington hook. Gross examination of the facet joints revealed areas of fibrillation, fissures, and thinning of the normal cartilaginous surface characteristic of osteoarthritis. Histologic examination revealed consistent areas of erosion of the vascular tidemark, osteophyte formation, subchondral remodeling, fibrillation, and loss of the normal cartilage cellularity. These findings were consistent with the histologic appearance of osteoarthritis. Internal fixation of the spine without arthrodesis is not an innocuous procedure and may be a predisposing factor in the development of symptomatic spinal arthritis.

Adolescent↗
PubMed1983

A locking hook-spinal rod: current status of development.

A locking hook spinal rod previously demonstrated to be sufficiently stable and strong in cadaver experiments has been employed in 30 unstable thoraco-lumbar spinal injuries with results superior to Harrington instrumentation.

Humans↗
PubMed1983

Diagnosis of post-traumatic syringohydromyelia presenting as neuropathic joints. Report of two cases and review of the literature.

Two paraplegic men with post-traumatic syringohydromyelia presented initially with neuropathic arthropathy of the elbow and shoulder, respectively. Both patients had sustained spinal trauma years earlier and had been lost to orthopedic and neurosurgical follow-up study. Characteristic history and physical findings were present in both patients. Conventional myelography failed to demonstrate the lesion in the first patient. The diagnosis in the second patient was confirmed by lumbar injection of low-dose metrizamide followed by immediate and delayed computerized axial tomography in the supine and lateral positions. Both patients were treated by surgical decompression and subarachnoid shunts with arrest of the neurologic deterioration. To the authors' knowledge, this is the first report of patients with post-traumatic syringohydromyelia presenting with neuropathic joints. The present case reports illustrate the need for long-term follow-up studies of patients with spine injury in specialty clinics. The use of computerized axial tomography and low-dose intrathecal metrizamide is advocated for diagnosing post-traumatic syringohydromyelia.

Adult↗
PubMed1983

Complicated extremity fractures. The relation between external fixation and nonunion.

In a series of 20 tibial fractures and ten radial fractures treated by external fixation, no association was found between the development of non-union and degree of soft tissue injury, delay in fixator application, or diaphyseal versus metaphyseal fracture site. Although the absence of fracture callus on roentgenograms of long bones immobilized by external skeletal fixation portends nonunion, no obvious cause-and-effect relation could be determined.

Adolescent↗
PubMed1981

Dynamic bone scanning in fractures.

In 20 cases routine static bone scans were no value in the detection of delayed fracture healing. Using the 7.5-15 min net uptake of technetium labelled phosphate, disturbed fracture healing was detected in a series, of 37 cases. Normally healing fractures had an increase of 3 per cent per month and delayed unions less than half that amount. Non-unions had no net uptake.

Bone Transplantation↗
PubMed1981

Effects of plates on cortical bone perfusion.

Using disulphine blue, sheep tibial cortex perfusion was decreased by subperiosteal stripping but not by extraperiosteal exposure. Semitubular plates applied with either low (20 kp) force, sufficient for extraosseous vascular occlusion, or high (200 kp) force, similar to that used clinically, both produced significant ischemia beneath the plate. In contrast, the dynamic compression plate produced significantly greater ischemia only with the higher force.

Animals↗
PubMed1980

Effects of fracture stabilization by internal fixation. I. A haemodynamic and blood gas evaluation of the systemic and regional changes.

The effect of internal stabilization of a fracture of the femur on arterial blood oxygen levels, limb flow and oxygen consumption was measured in 24 dogs. Those with stabilized fractures bore weight on their limbs and were much more active. Without fracture stabilization the arterial oxygen tension fell by 10 per cent. With internal fixation this hypoxia did not develop. In fact, there was a 10 per cent increase beginning in the third week. Stabilization of the fracture gave a persistent increase in limb blood flow, but without stabilization this increase was transient and followed by a significant decrease. Over the 7-week observation period, the total oxygen consumption of the uninjured limbs in the stabilized group was twice that in the unstabilized group, an indication of their functional activity. Also with stabilization, the oxygen consumption of the uninjured limb was not significantly different from the opposite limb, whereas without stabilization the consumption was 32 per cent greater, an indication of the energy cost of countering instability.

Animals↗
PubMed1980

Dorso-lumbar spine fractures: recumbent vs. operative treatment.

Internal fixation of fractures of the dorsal-lumbar spine with early ambulation is evaluated in this study of 100 patients with 106 fractures: 34 being treated by recumbency, 13 with Meurig-Williams plates, and 59 with Harrington rods. Fracture reduction in the recumbent group was 14 per cent unsatisfactory, 82 percent satisfactory, and only one case anatomical. Following plating, 38 per cent were unsatisfactory and 61 per cent satisfactory. Harrington rod reduction and internal fixation resulted in 67 per cent anatomical, 31 per cent satisfactory, and 2 per cent unsatisfactory. neurologic improvement in partial lesions was 53 per cent with Harrington rods and 44 per cent with recumbent treatment. For paraplegic patients the time required for wheelchair ambulation was reduced from 10.5 weeks with recumbent treatment to 5.3 weeks with Harrington instrumentation. Ambulatory candidate rehabilitation time was decreased from 7.1 weeks to 2.5 weeks. Complications were reduced from 18 per cent in the recumbent group to 7 per cent in the Harrington rod group. By using the three above-three below, rod long-fuse short approach rather than the two above-two below with fusion over the length of the rods technique, the number of anatomical reductions was increased from 70 per cent to 82 per cent and the length of the fusion decreased from 4.8 levels to 1.4 levels.

Adolescent↗
PubMed1979

Acute hyperthyroidism precipitated by trauma.

An adolescent girl presented to the emergency ward with a fracture of the femur and subtle indications of acute hyperthyroidism which progressed. The diagnosis was confirmed and treatment was instituted. In the care of acute trauma, the less obvious signs of an endocrinopathy must not be overlooked.

Accidents, Traffic↗
PubMed1979

The role of embolic fat in post-traumatic pulmonary insufficiency. An evaluation of the pulmonary haemodynamics and blood gas levels.

Pulmonary haemodynamic and arterial blood gas changes were measured in dogs subjected to either an intravenous injection of triolein or external trauma, which produced fractures of the ipsilateral femur, tibia and fibula. Musculoskeletal trauma resulted in pulmonary vasoconstriction followed by vasodilatation, arterial hypoxia with a pulmonary shunt of 30% and a 20% decrease in systemic oxygen delivery. Lipid injection produced an increased pulmonary vascular resistance, but no significant hypoxia, pulmonary shunting or inadequate tissue oxygenation. We therefore suggest that pulmonary fat embolism does not account for the pulmonary insufficiency following musculoskeletal trauma.

Animals↗
PubMed1978

External skeletal fixation in severe limb trauma.

Ten patients with 12 severe limb injuries managed by external skeletal fixation over 2 years are presented. Two major indications for external skeletal fixation divided the fractures into groups: A) extensively open fractures requiring wound care and closure by other than primary methods, and B) grossly unstable fractures requiring stabilization for soft-tissue support and fracture alignment. Group A was composed of five extremity fractures with skin and muscle loss and deep tissue contamination. Wound management was the primary problem. Wound closure, prevention of an infection, and limb salvage were the treatment goals in this group. Group B was seven severely comminuted extremity fractures with significant swelling and in some cases, questionable soft-tissue survival. Five were open, but not extensively. Instability was the primary problem. Fracture control, soft-tissue support, and limb salvage were the treatment goals in this group. Mean followup period for all fractures was 9.4 months. No amputations, deep infections, or deaths resulted. Wound care and closure were facilitated in all open fractures. Loss of contused tissues with marginal vascular supply was felt to be minimized. Delayed unions were common in both groups. Two malunions and one nonunion occurred. Treatment goals in both groups were accomplished.

Adolescent↗