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Biomedical subjects

H H Bohlman

Publications and source records attributed to H H Bohlman.

At least 19 recordsLinked to original sources
PubMed1992

Techniques of subaxial posterior cervical spine fusions: an overview.

The various methods for posterior cervical stabilization techniques allow successful fusion in almost all instances and indications. The choice is primarily dependent on the surgeon's training, experience, and preference, and is subsequently narrowed by the available intact and stable anatomy unique to each patient's injury. Despite the availability of multiple stabilization techniques and their widespread use, these techniques should be performed only by surgeons familiar and comfortable with the approach, anatomy, and stabilization techniques, and with the care of patients with mechanical and neurological injuries to the cervical spine.

Biomechanical Phenomena↗
PubMed1992

Postoperative cerebrospinal-fluid fistula associated with erosion of the dura. Findings after anterior resection of ossification of the posterior longitudinal ligament in the cervical spine.

Of twenty-two patients who had had anterior decompression of the spinal canal for ossification of the posterior longitudinal ligament and cervical myelopathy, seven had absence of the dura adjacent to the ossified part of the ligament. The spinal cord and nerve-roots were visible through this defect. Although the arachnoid membrane appeared to be intact and watertight in most patients, a cerebrospinal-fluid fistula developed postoperatively in five, and three had a second operation to repair the defect in the dura. On the basis of this experience, we recommend use of autogenous muscle or fascial dural patches, immediate lumbar subarachnoid shunting, and modification of the usual postoperative regimen, such as limitation of mechanical pulmonary ventilation to the shortest time that is safely possible and use of anti-emetic and antitussive medications to protect the remaining coverings of the spinal cord when the dura is found to be absent adjacent to an ossified portion of the posterior longitudinal ligament in the cervical spine.

Adult↗
PubMed1992

Anterior decompression and arthrodesis of the cervical spine: long-term motor improvement. Part I--Improvement in incomplete traumatic quadriparesis.

Between 1973 and 1983, fifty-eight patients who had an incomplete spinal-cord injury secondary to a fracture or dislocation of the cervical spine were managed by anterior cervical decompression and arthrodesis with iliac bone grafts. In all patients, myelography showed that displaced fragments of bone or disc were compressing the anterior aspect of the spinal cord. Anterior decompression was performed in an attempt to improve function in the upper and lower extremities. The average interval from the injury to the decompression was thirteen months (range, one month to nine years). Two patients died of cardiopulmonary disease within two months after the operation, and one patient died eighteen months after the operation. The remaining fifty-five patients were followed for an average of six years (range, two to seventeen years). Twenty-nine patients became functional ambulators after the operation. An additional six patients who could walk before the operation had improvement in the ability to walk. Noteworthy improvement in motor-root function in the upper extremities was seen in thirty-nine patients. Only nine patients had no signs of improvement of motor function. Improvement was less in the patients in whom operative decompression had been done more than twelve months after the injury. The patients who had an extension injury to a spondylotic spine were older, and fewer of them had improvement. No patient lost neurological function as a result of the operation. Anterior decompression and arthrodesis, even when performed late after the injury, can improve neurological function in both the upper and lower extremities in many patients who have incomplete quadriplegia due to a fracture or dislocation of the cervical spine.

Adolescent↗
PubMed1992

Anterior decompression and arthrodesis of the cervical spine: long-term motor improvement. Part II--Improvement in complete traumatic quadriplegia.

Fifty-one patients who had complete motor quadriplegia secondary to a fracture or dislocation of the cervical spine were managed by anterior cervical decompression and arthrodesis with iliac bone grafts between 1973 and 1983. In all patients, myelography demonstrated that displaced fragments of bone and disc were compressing the anterior aspect of the spinal cord. Decompression was performed in an attempt to gain further improvement of the motor-roots in the upper extremities and thereby to improve the ability of the patients to care for themselves. The average interval from the injury to the decompression was fifteen months (range, one month to eight years). Two patients died within two months after the operation, one had a respiratory arrest that resulted in brain damage one day after the operation, and two died from cardiovascular disease more than one year after the operation. The remaining forty-six patients were followed for an average of five years (range, two to thirteen years). Neurological improvement of at least two new functional motor-root levels was documented in seven patients and of one level, in eighteen. Increased motor strength by two or three grades was seen in six patients. Noteworthy motor improvement did not occur in the remaining twenty patients. The mean modified Barthel index (used to measure improvement in the ability to perform activities of daily living) increased from 17 to 33 (of a possible 100) points. Functionally important improvement of the caudad part of the cord occurred in only one patient. In one patient, neural injury, with loss of one motor-root level, occurred, with only partial improvement. At the latest follow-up examination, the result was poor in nine of eleven patients who had decompression eighteen months or more after the injury. Only two of these patients had any improvement in the Barthel index, and then of only 5 points each. The result also was poor in the five patients who were more than fifty-three years old; two had no improvement in the Barthel index, one improved by 5 points, and two died.

Adolescent↗
PubMed1991

Mediastinal widening associated with fractures of the upper thoracic spine.

Widening of the mediastinum, when seen on radiographs of the chest in victims of trauma, is usually attributed to injury to the aorta. An aortic injury, when not lethal, often causes paraparesis or paraplegia due to ischemia of the spinal cord. A fracture of the upper thoracic spine can produce similar clinical and radiographic findings. The cases of three patients who had those findings are presented; in all three, the differential diagnosis between the vascular and skeletal injuries was difficult. Fracture of the thoracic spine should be included in the differential diagnosis whenever mediastinal widening is seen on radiographs.

Accidents, Traffic↗
PubMed1991

Upper-airway obstruction after multilevel cervical corpectomy for myelopathy.

We reviewed the cases of seven patients who had had obstruction of the upper airway immediately after an anterior procedure on the cervical spine and had required reintubation. All patients had had moderate or severe myelopathy preoperatively (average, 3.6 on the Nurick scale), and all had had a multilevel anterior cervical corpectomy for decompression followed by arthrodesis. The early compromise of the upper airway was believed to be due to edema rather than to the formation of a hematoma. Five patients had no sequelae, but two died of complications related to the obstruction. Risk factors common to these patients included moderate or severe myelopathy and multilevel corpectomy. Six patients had a history of heavy smoking and one, of asthma. We believe that extra caution should be used in the postoperative management of the airways when multilevel corpectomy is performed in patients who have these pre-existing conditions.

Aged↗
PubMed1990

Urologic changes after cauda equina compression in dogs.

Relative degrees (25%, 50% or 75%) of constriction of the entire cauda equina at the seventh lumbar level were performed on eighteen pure bred female beagle hounds by surgically implanting a circular polyethylene loop with an imbedded stainless steel wire. The wire was mechanically constricted by external control and the degree of compression was confirmed by pre- and postoperative magnetic resonance imaging or computed tomography scanning. A control group of two dogs had laminectomy only. Neurologic function was evaluated daily. Cystometrics were performed on each dog after constriction had been present for three months. Cortical evoked potentials (CEPs) were obtained on all dogs preoperatively, immediately following constriction and at monthly intervals for three months. Dogs were sacrificed at three months and the cauda equina and spinal cord were examined histopathologically. Cystometric tracings were noted to become a flat line with 75% compression of the cord. Less compression had minimal effect on the cystometric curves. The mean latency, determined by cortical evoked potentials, was noted to increase by 3.2%, 7.8%, and 17.2% immediately after 25%, 50% and 75% constriction, respectively. Histologic changes ranged from occasional enlargement of the axons on the periphery of the cauda equina with 25% constriction to severe loss of all axons and atrophic roots at the level of the constricting band with 75% constriction.

Animals↗
PubMed1990

Diagnosis of lumbar arachnoiditis by magnetic resonance imaging.

Twenty-four cases of lumbar arachnoiditis were evaluated by magnetic resonance (MR) imaging. The morphologic changes of arachnoiditis by MR were compared in 20 cases with CT myelography (CTM) and plain film myelography (PFM). An abnormal configuration of nerve roots was seen by MR. Three anatomic groups were identified. Group 1 showed conglomerations of adherent nerve roots residing centrally within the thecal sac. Group 2 demonstrated nerve roots adherent peripherally to the meninges, giving rise to an "empty sac" appearance. Group 3 showed a soft tissue mass replacing the subarachnoid space. Magnetic resonance imaging resulted in accurate diagnosis, and had excellent correlation with CT myelography and plain film myelographic findings in the diagnosis of lumbar arachnoiditis.

Arachnoiditis↗
PubMed1990

Urologic function after experimental cauda equina compression. Cystometrograms versus cortical-evoked potentials.

Twenty female beagle dogs underwent an L6-7 laminectomy and six dogs each had 25, 50 or 75% constriction of the cauda equina and 2 control dogs had laminectomy only. Cystometrograms were performed pre- and post-operatively and three months after constriction. Cortical evoked potentials were monitored pre- and post-operatively and monthly for three months. After three months of constriction, the cauda equina of these dogs in each group was examined histologically and vascular circulation was examined by latex and India ink injection (Spalteholz technique). The control dogs had normal CMGs and CEPs. Twenty-five percent constriction caused no CMG changes and mild CEP changes. Fifty percent constriction caused no statistically significant CMG changes, major CEP changes and venous congestion of the nerve roots and dorsal root ganglia. Seventy-five percent constriction produced severe CMG changes with detrusor areflexia, increased bladder capacity and clinical incontinence. CEPs also had marked deterioration. Vascular analysis revealed severe arterial narrowing at the level of constriction and venous congestion of the nerve roots and dorsal root ganglia. Blockage of axoplasmic flow and nerve root atrophy was seen in all dogs with 75% constriction. Cortical evoked potentials were the most sensitive predictor of neural compression. CMGs were not sensitive until severe compression was achieved. Bladder dysfunction, i.e., detrusor areflexia, appears to occur with blockage of axoplasmic flow and early sensory changes occur with neurovenous congestion.

Animals↗
PubMed1990

Primary neoplasms of the thoracic and lumbar spine. An analysis of 29 consecutive cases.

Primary osseous neoplasms of the thoracic and lumbar spine are uncommon lesions. Between 1965 and 1982, of 1971 patients with musculoskeletal neoplasms, only 29 (1.5%) had primary osseous tumors in these locations. There were eight children and 21 adults. Back pain was the most common complaint in 25 patients (86%), and neurologic symptoms or deficits were present in 16 patients (55%). All lesions were visible on routine spine roentgenograms, while computed tomography and myelography demonstrated spinal canal encroachment and extradural spinal cord compression in 19 patients (66%). The histologic diagnoses included 11 benign and 18 malignant lesions. Benign lesions occurred predominantly in children and malignant tumors in adults. Treatment was individualized, based on the histologic diagnoses. Twenty-two patients had surgical resection of their lesions. Laminectomy without stabilization and arthrodesis resulted in late instability and neurologic deterioration in three of seven patients (43%) with malignant lesions. Resection and decompression combined with arthrodesis did not predispose to late instability. Twenty-one patients were followed for a mean of 4.1 years (range, two to 14 years). Eight patients died from malignant disease between one month and seven years after diagnosis.

Adolescent↗
PubMed1990

Experimental lumbar spinal stenosis. Analysis of the cortical evoked potentials, microvasculature, and histopathology.

An animal model of lumbar spinal stenosis was developed in which the pathophysiology of this condition could be examined. Four experimental groups, each containing six dogs, were studied. One group had a laminectomy of the sixth and seventh lumbar vertebrae only; these animals served as controls. In the three other groups, a laminectomy was performed and the cauda equina was constricted by 25, 50, or 75 per cent to produce chronic compression. Cortical evoked potentials were recorded preoperatively, immediately after constriction, and at one, two, and three months postoperatively. Daily neurological examinations were carried out, and the neurological deficits were graded using the Tarlov system. After three months of constriction, the cauda equina of three dogs in each group was examined histologically, and the vascular circulation was examined by latex and India-ink injection with a modification of the Spalteholz technique. The animals in the control group showed no neurological abnormalities, no changes in cortical evoked potentials, normal microvascularity, and no histopathological changes in the nerve roots or the spinal cord. The dogs in which the cauda equina had been constricted 25 per cent had no neurological deficits, mild changes in cortical evoked potentials, slight histological changes, and venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 50 per cent had mild initial motor weakness, major changes in cortical evoked potentials, edema and loss of myelin in the root of the seventh lumbar nerve, and moderate or severe venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 75 per cent had significant weakness, paralysis of the tail, and urinary incontinence; two dogs recovered by the third month, but all had neurogenic claudication for three months. All six dogs had dramatic changes in cortical evoked potentials and had complete nerve-root atrophy at the level of the constriction. There was blockage of axoplasmic flow and wallerian degeneration of the motor nerve roots distal to the constriction and of the sensory roots proximal to the constriction, as well as degeneration of the posterior column. Severe arterial narrowing at the level of the constriction and venous congestion of the roots and dorsal root ganglia of the seventh lumbar and first sacral nerves were also present. Cortical evoked potentials revealed neurological abnormalities before the appearance of neurological signs and symptoms.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Spondylolisthesis treated by a single-stage operation combining decompression with in situ posterolateral and anterior fusion. An analysis of eleven patients who had long-term follow-up.

We treated eleven skeletally mature patients who had a high-grade lumbosacral spondylolisthesis by a single-stage operation that involved posterior spinal decompression, posterolateral arthrodesis with autogenous iliac-crest graft, and anterior arthrodesis with a fibular graft inserted from the posterior approach. We did not attempt to correct the deformity. Preoperatively, all but one patient had severe pain in the back and lower limb; the exceptional patient had severe pain only in the low back. All but one patient had sensory deficits and objective motor impairment before the operation, and five had cauda equina syndrome. Six patients had had a previous operation that had failed. The duration of follow-up ranged from two to twelve years. A solid fusion was obtained in all patients, and all had major or complete neurological recovery. The results did not deteriorate with time.

Adolescent↗
PubMed1989

Magnetic resonance imaging of posttraumatic spinal ligament injury.

We evaluated the role of magnetic resonance imaging (MRI) in the detection of ligament injury in 37 patients after acute traumatic spinal injury. Thirty-five patients had fractures, one had neurologic deficit with normal x-rays, and one had evidence of cervical instability on flexion/extension plain films. MRI examinations were performed acutely (average 10.8 d after injury) using T1- and T2-weighted multiplanar imaging. Two radiologists blindly evaluated all MRI examinations. Subsequently, 35 plain films, 16 tomograms, and 30 computed tomography (CT) scans were also evaluated. Nineteen patients were considered to have torn posterior ligaments on the basis of their clinical, radiographic and surgical findings. MRI detected ligament damage in 17. All patients considered to have intact posterior ligament complexes clinically and radiographically had no evidence of ligament damage on MRI. T2-weighted sequences were essential for detection of ligament injury. We conclude that MRI is an accurate method for assessment of the integrity of spinal ligaments after acute trauma.

Adolescent↗
PubMed1989

Cervical kyphosis and myelopathy. Treatment by anterior corpectomy and strut-grafting.

Between 1976 and 1984, fourteen patients who had severe cervical kyphosis and myelopathy were treated with anterior decompression and arthrodesis. Eight had had spondylosis; five, a traumatic injury; and one, a benign intradural tumor. In eight of the fourteen patients, the severe kyphosis and myelopathy had developed after a laminectomy of three, four, or five cervical vertebrae. The laminectomy had been done for the treatment of spondylosis in five patients, of a traumatic lesion in two, and of a tumor in one. Considering all fourteen patients, an average of 2.25 vertebral bodies was removed from each, and the average extent of the subsequent fusion was 3.25 levels. Eight patients (six of whom had spondylosis; one, a traumatic lesion; and one, a tumor) were treated with a fibular graft that spanned an average of 4.10 levels, and six patients (four of whom had a traumatic lesion and two, spondylosis) were treated with an iliac graft that spanned an average of 2.70 levels. Of the five patients who had a traumatic lesion, four were treated with anterior decompression and arthrodesis, combined with posterior arthrodesis that was performed during the same period of anesthesia. In three patients, the anterior graft dislodged during the immediate postoperative period. Two of the three patients had posterior instability due to a prior laminectomy, and in the third the graft dislodged because of technical difficulties. Two of these grafts were revised to restore stability. At the latest follow-up, twelve of the fourteen fusions were solid. In the other two patients, who died six and ten months postoperatively, the fusion had been solid, as shown by radiographs, before the time of death. The average amount of correction of the kyphotic deformities was 32 degrees, a reduction from an average of 45 degrees to an average of 13 degrees. All but one patient had some recovery of neural function; nine had complete and four, partial recovery. The remaining patient had relief of pain, but he continued to be completely quadriplegic although he had some sensory sparing. Of the four patients who had been unable to walk preoperatively, three were able to walk postoperatively. No patient lost neural function after the anterior decompression and arthrodesis. We concluded that, in the presence of severe cervical kyphosis and myelopathy, adequate anterior decompression of the spinal cord, correction of the kyphosis, and anterior arthrodesis using a strut graft can yield excellent results without undue risk.

Adult↗
PubMed1989

Degenerative spondylolisthesis.

Degenerative spondylolisthesis is a unique form of spondylolisthesis that is characterized in most patients as a hypertrophic arthritis of the facet joint resulting in segmental instability predominantly in the sagittal plane. Disk degeneration is associated with degenerative spondylolisthesis to a varying degree. Joint involvement may not be uniform in all patients, and a rotary component, although small, is often present. The fourth to fifth lumbar level is most often involved, particularly in association with a relatively rigid lumbosacral segment. Degenerative spondylolisthesis is more common in females and in blacks, and it seldom occurs before the age of 40 years. Symptoms are generally due to lateral stenosis that compromises the inferior nerve roots, usually at the level of the fifth lumbar vertebra. However, the superior nerve roots can be compressed in more advanced cases. Neurogenic claudication and radiculopathy are commonly reported symptoms at the time a patient is first examined. The findings of physical examination vary; less than half of the patients examined exhibit a neurologic deficit. Rarely, a patient has cauda equina syndrome at the time of initial examination. Mild cases can be successfully treated surgically, but significant neurologic symptoms can only be diminished by adequate decompression. We recommend posterolateral fusion because of the deformity's propensity to progress postoperatively.

Humans↗
PubMed1989

One-stage anterior cervical decompression and posterior stabilization with circumferential arthrodesis. A study of twenty-four patients who had a traumatic or a neoplastic lesion.

Twenty-four patients had a combined anterior cervical decompression and posterior stabilization with circumferential spinal arthrodesis for treatment of either a tumor or an injury. The indication for operation was a fixed kyphosis and an incomplete neurological deficit or cervical instability. All but two patients had substantial improvement, having regained strength or had a reduction in the deformity, or both. The two exceptional patients, both of whom were quadriparetic, had no change. The operation is formidable and requires an average of 6.9 hours of general anesthesia; however, its use is justified in patients who have the appropriate indications.

Adolescent↗