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Biomedical subjects

R B Raynor

Publications and source records attributed to R B Raynor.

16 recordsLinked to original sources
PubMed1999

Postoperative gas bubble foot drop. A case report.

STUDY DESIGN: An unusual case of foot drop occurring 10 days after disc surgery is reported. Imaging studies identified a gas bubble compressing the nerve root. OBJECTIVE: To describe the origin and management of a radiculopathy caused by an intraspinal gas bubble. SUMMARY OF BACKGROUND DATA: A recurrent lumbar disc herniation was diagnosed by clinical and imaging studies. A vacuum disc also was noted at the same level. These are common and not considered to be of pathologic significance. METHODS: The patient underwent a microdiscectomy for a lumbar disc extrusion. The postoperative course was excellent, with relief of symptoms and no neurologic deficit. Ten days later, the awoke with a foot drop and pain in the leg. Imaging studies showed a 4-mm gas bubble compressing the nerve root. Oral steroids were given for 10 days. RESULTS: Progressive improvement occurred, and the patient was asymptomatic 6 weeks later. Although in some instances it may be necessary to evacuate intraspinal gas, an initial period of observation is warranted, because the gas and its resulting symptoms may disappear spontaneously. CONCLUSION: Intradiscal gas accumulation, better known as vacuum disc, is considered to be a benign indication of degenerative disc disease. On occasion it can be a cause of symptoms. A case is reported in which gas leaked after surgery into the spinal canal, causing a foot drop. The symptoms and gas disappeared spontaneously without further treatment.

Adult↗
PubMed1997

Intraoperative ultrasound for immediate evaluation of anterior cervical decompression and discectomy.

STUDY DESIGN: An evaluation of whether the immediate operative results can be improved in anterior cervical surgery in patients in whom disc fragments could remain hidden behind a vertebral body or far laterally in the foramen or in canal stenosis that involved a significant amount of a vertebral body. OBJECTIVES: To determine whether intraoperative ultrasonography can provide immediate evaluation of the decompression. SUMMARY OF BACKGROUND DATA: The anterior cervical approach has anatomic limitations that prevent good visualization of deep structures. Sequestered disc fragments can be hidden behind the bone of the vertebral body. Even careful preoperative measurements cannot ensure adequate length and width of decompression for stenotic lesions. METHODS: Three groups of patients were studied. Group 1 contained seven patients with soft disc herniations that were either behind the vertebral body or extended laterally into the neural foramen. Group 2 consisted of five patients with canal stenosis involving at least one third of the length of a vertebral body and causing myelopathic signs and symptoms. Group 3 consisted of four patients with radicular and cord symptoms. All were studied with either magnetic resonance imaging or computed tomography myelography or both. The size of the desired decompression was measured from these studies. A standard anterior decompression using magnification was performed that satisfied the surgeon's visual and tactile evaluation. The operative site was imaged ultrasonically and the decompression extended until preset imaging criteria were met. These criteria were clear root visualization for radiculopathy and good dural pulsations for stenotic lesions. RESULTS: Twelve of the 16 patients did not meet the set criteria on initial imaging, and 11 had their decompression extended. A hidden lateral disc fragment was found in one. In this selected group of 16 patients with complicated cervical pathology, 14 improved neurologically after the use of ultrasonic guidance intraoperatively. One error of interpretation was made. One patient who did not meet the ultrasonic decompression criteria and did not have the decompression extended did not improve after surgery. CONCLUSIONS: In complicated anterior cervical decompressions, intraoperative ultrasonic imaging provides immediate evaluation of the extent of the decompressive procedure and may improve the operative result.

Cervical Vertebrae↗
PubMed1991

Cervical spine strength after facet injury and spine plate application.

Although metallic plates are used for cervical spine stabilization, few biomechanical studies have been done to evaluate their efficiency. A previous study indicated that one half of the facet joint may be destroyed before compromise in strength occurs. Isolated motion segments in which one half of the facet joint was resected bilaterally were used. A two-hole Roy-Camille plate was attached bilaterally with 3.5-mm-diameter, 16-mm-long screws and the construct loaded in shear. Failure occurred at 415.6 N by fracture through the screw holes of the damaged joint, compared to a failure load of 699.6 N in specimens without screws and plates but in which 75% of the joint had been destroyed. Results were significant at the 95% confidence level. A second group of specimens using C2-3-4 and C5-6-7 was tested after 50% facet resection and application of a three-segment plate. Failure again occurred by fracture through the screw hole at the damaged joint. We conclude that, if significant facet destruction is present, screw holes for plate application further weakens the bone. The desired biomechanical stability may not be present.

Bone Plates↗
PubMed1987

Alterations in primary and coupled neck motions after facetectomy.

Normal neck motion is a complicated phenomenon. A primary motion results from an applied force or torque. Secondary coupled motions also result as a consequence of the primary motion. These resulting coupled motions were measured in isolated cervical motion segments using three-dimensional videophotogrammetry with a coordinate system fixed in space. A cross coupling algorithm provided error correction and conversion from local to true cartesian coordinates. The data were analyzed by computer, and the true coupled motions resulting from any applied force were obtained. A second group of specimens was facetectomized, and the experiments were repeated. After facetectomy, a moment about the anteroposterior axis resulted in marked reduction in lateral displacement, decrease in vertical displacement, and decrease in rotation about the vertical axis. Results were significant at P less than 0.01 and represent a significant decrease in coupled motions resulting from lateral bending. At P less than 0.05, a laterally applied force causes less lateral displacement and lateral flexion, but more longitudinal displacement. Flexion and extension movements are not significantly altered after facetectomy.

Biomechanical Phenomena↗
PubMed1986

The Arnold-Chiari malformation.

The Arnold-Chiari malformation is a developmental abnormality of the brainstem and cerebellum with displacement of these structures into the cervical spinal canal. Other anomalies involving the base of the skull and vertebral bodies are frequently present. In children, hydrocephalus and myelomeningocele may complicate the picture. In adults, symptoms usually do not occur until the third to fifth decade and then are often misdiagnosed as degenerative disease due to the presence of a syrinx in the cord. Treatment is focused on decompressing the spinal cord and brainstem.

Adult↗
PubMed1986

Charcot's spine with neurological deficit: computed tomography as an aid to treatment.

A patient with Charcot's disease of the lumbar spine presented with weakness of one extremity. Myelographic and x-ray film studies indicated stenosis and compression due to degenerative changes. Although decompression and fusion were considered, computed tomographic scans indicated the wide extent and location of the destructive changes. Nonoperative treatment was elected because of the high risk of fusion failure and instability.

Arthropathy, Neurogenic↗
PubMed1985

Cervical facetectomy and its effect on spine strength.

Fourteen cervical spine motion segments consisting of two adjacent vertebral bodies and their connecting ligaments were tested in shear. Five had intact facet joints, five had bilateral facetectomy of 50% or less, and four had bilateral 70% facetectomy. Three to 5 mm of root could be exposed in the specimens with 50% facetectomy, and 8 to 10 mm in those with 70% facetectomy. Anterior-posterior shear tests were run alternately in compression and distraction. Facetectomy was found to have no effect on compression and distraction stiffness. Failure in the 70% facetectomized specimens was due to fracture of the remaining joint at 159 lbs. In the specimens with 50% facetectomy, a fracture load could not be established since failure of the specimen mounting occurred at 208 lbs, as it did in two of the specimens without facetectomy that were tested to failure. The difference in bone fracture at 159 lbs and mounting failure at 208 lbs is significant at p less than 0.05. Bilateral resection of more than 50% of the facet joint significantly compromises the shear strength of a cervical spine motion segment.

Cervical Vertebrae↗
PubMed1985

Cervical cord trauma. The relationship between clinical syndromes and force of injury.

Several different syndromes, such as central cord, anterior cord, and root, have been described in injuries to the cervical spine. If stress analysis theory is used to analyze the applied forces that cause injury, the various syndromes appear to be interrelated and follow in an orderly progression that depend on the magnitude of the applied force. The modes of injury, either flexion or extension, theoretically produce similar injuries, dependent on the severity of the blow. These applied forces then cause the pathologic changes that have been described. This article applies commonly used principles of engineering design to analyze clinical syndromes and to demonstrate that these syndromes are related in a sequential manner.

Biomechanical Phenomena↗
PubMed1983

Anterior or posterior approach to the cervical spine: an anatomical and radiographic evaluation and comparison.

Both the anterior and the posterior approaches are used in the treatment of cervical radiculopathy. An evaluation of the advantages and limitations of each method as compared to the other was made in isolated cervical spine segments. With a posterior approach, a quarter to a half of the facet joint must be removed to unroot the neural foramen. Anterior osteophytes in the region of the uncovertebral joint are difficult to reach from posteriorly unless they are very large. Using an anterior approach the amount of root decompression is easily overestimated. The lateral limits of the decompression must be beyond direct visualization to equal that obtained posteriorly. Osteophytes in the region of the uncovertebral joints are easily reached. Because some roots leave the dural tube a significant distance above the interspace, a soft disc fragment may migrate out of the interspace and behind the body to compress the root. This fragment may be missed from the anterior approach unless the root anatomy is evaluated carefully. X-ray films were taken at each step of the surgical procedures and were compared. A final set was taken using radiopaque markers to identify key structures. Plain x-ray films of the cervical spine reflect few if any of the anatomical alterations accomplished by operation. Oblique x-ray films do not visualize the entrance of the anatomical foramen, and osteophytes seen on this view may be well anterior in the neural canal.

Cervical Vertebrae↗
PubMed1982

Transthoracic approach to an intramedullary vascular malformation of the thoracic spinal cord.

A transthoracic approach with resection of a vertebral body was used to obtain access to an intramedullary vascular malformation of the thoracic spinal cord. The malformation consisted of three discrete intramedullary tufts of vessels fed by an abnormal branch of the anterior spinal artery arising from the T-9 intercostal artery. Although the abnormal branch of the anterior spinal artery did not appear to supply normal cord, the patient developed transient weakness postoperatively after occlusion of this artery. Follow-up angiography showed that one part of the malformation was still present and was fed by the T-y intercostal artery.

Adult↗