Search PubMed⌕ Search

Biomedical subjects

H H Sherk

Publications and source records attributed to H H Sherk.

At least 37 records · Page 2Linked to original sources
PubMed1992

Accurate compartment pressure measurement using the Intervenous Alarm Control (IVAC) Pump. Report of a technique.

This study demonstrates the accuracy of a common, readily available pressure transducer system (IVAC pump) for the measurement of compartment syndromes. An in vitro assay was used to compare the accuracy of the IVAC pump manometer with the Hewlett-Packard monometer (HP78532B) and a miniaturized digital fluid pressure manometer (Stryker). The IVAC pump was accurate within 2.4 mm Hg difference of the HP78532B and Stryker manometers. Twenty-five patients suspected of having compartment syndrome posttibial fracture had compartment pressures measured using the IVAC pump. In all the patients, compartment syndrome was accurately assessed (positive in one case and negative in the remainder). The IVAC pump is readily available in most hospitals. It is easy to use and provides accurate measurements of compartment pressures.

Compartment Syndromes↗
PubMed1991

Treatment versus non-treatment of hip dislocations in ambulatory patients with myelomeningocele.

Thirty myelomeningocele patients with untreated hip dislocations who had functional quadriceps and good ambulatory capability were evaluated for hip pain, hip motion and sitting ability: they had no pain, good to excellent hip motion and no difficulty in sitting. Three were wheelchair-bound. Nine had a limb-length inequality requiring a shoe lift. They were compared with a similar series of 11 patients who underwent open reduction of a dislocated hip with a two-year follow-up. Two patients in this group had improved and three had worse sitting balance. Serious perioperative complications occurred in six patients. The authors conclude that surgical reduction of paralytic hip dislocations in ambulatory myelomeningocele patients is costly and offers little obvious benefit.

Adolescent↗
PubMed1991

Contamination of operating room personnel during total arthroplasty.

The authors prospectively evaluated the degree of contamination to the operating room team during 60 consecutive total joint arthroplasties. Each member of the team was required to wear a hood, mask, protective eyewear, and shoecovers. At the conclusion of each procedure, all members were assessed in terms of degree and location of contamination. One hundred percent of the surgeons and first assistants were exposed. The face and eyewear were noted to be the area of greatest contamination. The authors found orthopedic surgeons to be at significant risk of contamination with blood and body fluids during total joint arthroplasty.

Blood↗
PubMed1988

Biomechanical evaluation of the extensor musculature of the cervical spine.

Dissection of the musculature in the cervical spines of four cadavers indicated that the semispinalis cervicis and capitis muscles appeared to be the muscles primarily responsible for extension of the cervical spine and head. The minimum force needed to balance a biomechanical model of the cervical spine in the neutral prone position against gravity measured 14.38 kg. The values obtained with this model, with roentgenograms of the cervical spine, and vector analysis were close enough to establish that the model is apparently valid for studying the extensor musculature of the cervical spine. Because the extensors appear to generate considerable force and may act as significant dynamic stabilizers of the cervical spine, the authors have altered their posterior surgical approach to minimize disruption of the extensor musculature.

Cervical Vertebrae↗
PubMed1988

The vertical stability of the cervical spine.

The concept of the three-column cervical spine and load transmission through each column was experimentally tested. Material consisted of five cervical columns removed from cadavers. The experiment was conducted on an Instron load testing machine. Load was applied on superior articular surfaces of the axis vertebra and was recorded below from each column separately at the level of the sixth cervical vertebra. It was found that 36% of the total load applied on the top of the specimen is transmitted through the anterior column formed by bodies and intervertebral discs and 32% each through the two posterior cervical columns formed by the articular processes. The experiment very strongly supported the role of neural arch in transmission of vertebral compressive forces.

Biomechanical Phenomena↗
PubMed1988

High resolution analysis of ground foot reaction forces.

A new system of hardware and software has been designed for quantitative high resolution analysis of ground foot pressures during stance and gait. In the system, a large photoelastic sheet is used as the transducer and a computerized video system for analysis and display. This system offers a larger active surface at higher resolution and at lower cost than any other system heretofore described. It will be used to predict diabetic plantar ulceration as well as to detect anatomic and motor defects affecting the feet.

Computer Graphics↗
PubMed1988

Treatment of tumors of the cervical spine.

In 34 patients with primary or metastatic tumors of the cervical spine over a ten-year period, the presenting symptom was neck pain. Eleven patients demonstrated evidence of radiculopathy, one a myelopathy, and three a combined myeloradiculopathy. Surgical stabilization, combined in eight cases with cord decompression, successfully relieved pain and prevented further neurologic deterioration in 17 of 18 patients with radioresistant tumors. Complications included two patients who were treated with short posterior fusions displacing as a result of tumors progressing above and below the fusion, and one patient in whom an anterior methacrylate mass became dislodged and appeared to jeopardize the esophagus. Methacrylate was used to augment the grafts posteriorly to facilitate early mobilization without the need for a halo splint. Mean patient survival was not significantly increased by surgical intervention (26 weeks vs. 20 weeks). While most lesions of the cervical spine can best be managed by nonoperative methods, in selected patients long posterior fusion with wires and methacrylate appears successful in relieving pain, halting progress of neurologic deficits, and facilitating early mobilization.

Adolescent↗
PubMed1987

The natural history of hip dislocations in ambulatory myelomeningoceles.

We studied 22 myelomeningocele patients with strong quadriceps and good ambulatory capability who had a dislocated hip. These patients did not have hip pain, had good to excellent hip motion and could sit with no difficulty. All but one was a good to excellent community ambulator with crutches and orthoses. Twenty-five percent had limb length inequality requiring shoe lifts but this combination did not impair functional capability. None owned wheelchairs. Seven had associated musculo-skeletal deformities which required treatment. We concluded that the hip dislocation in these patients was not significant. We evaluated a similar series of 11 patients who had open reduction of a dislocated hip an average of 18 months ago. Two patients were slightly improved and five patients were significantly worse after the open reductions. Serious complications related to the surgery ensued in half of the cases. The cost of the surgery and treatment of the complications in these 11 patients was $400,000. We concluded that surgical treatment of paralytic hip dislocations in ambulatory myelomeningocele patients offered no clear cut benefit.

Child↗
PubMed1986

Hydrocephalus, cervical cord lesions, and spinal deformity.

Twenty-six children (4-16 years) had hydrocephalus and spinal deformity; 22 children had scoliosis over 50 degrees, and five children had kyphosis over 100 degrees. Twenty-one children had metrizamide enhanced cord CT scans, and 12 had additional head scans. Two children died, and one was autopsied. Three children had intracranial pressures monitored during spinal surgery. All children had Type I and II Arnold-Chiari malformations, 58% had cord cavitation (syringo/hydromyelia), 67% had cord tethering. The anatomic study showed extensive fibrosis and scarring of the upper cord and brain stem, but intraoperative studies showed that there is free transmission of fluid pressure wave from the cord across the foramen magnum with a consequent rise in intracranial pressure. This study documents frequent coexistence of spinal deformity and central nervous system lesions (hydrocephalus, Arnold-Chiari malformation, cord tethering with atresia, and cord cavitation). It supports the theory that the Arnold-Chiari malformation is a primary developmental deformity and that cord cavitation noted in these patients is primarily syringomyelia formed on the basis of ischemic necrosis within the cord. The free transmission of a fluid pressure wave from the cord to the lateral ventricle supports the Williams theory of propagation of syringomyelic cavities once they have developed. It is conjectural but likely that the CNS lesions cause spinal deformity by disrupting coordinating control of spinal musculature by the normal postural reflex mechanisms. Hydrocephalic patients who develop spinal deformity require thorough investigation for CNS lesions with head scans, CT scans, and metrizamide enhanced CT scans. NMR technology, however, may supplant techniques currently employed.

Adolescent↗
PubMed1985

Analysis of ground-foot reaction forces in patients with myelomeningocele.

This paper describes a system for evaluation of ground-foot reaction forces in which multiple 1 centimeter diameter metal coated points transmit pressure to a photoelastic sheet. The pressure generates circular interference patterns, the diameters of which are linearly related to the pressure applied. The system permits the computerized construction of a three-dimensional contour map which can be compared to a pedobarograph. The qualitative/quantitative assessment system can identify areas on the plantar aspect of the foot at risk for skin breakdown. This information will permit treatment to proceed on a more rational basis than has been possible heretofore.

Biomechanical Phenomena↗
PubMed1984

The pathogenesis of progressive cavitation of the spinal cord.

It has been suggested that the pathogenesis of cord cavitation is multifactorial, but that there may be a common mechanism, if not for their actual cause then at least for the increase in size. A case is discussed in which the location of the cavitation suggested the cause was chronic ischemia of vascular origin.

Child, Preschool↗
PubMed1983

Central nervous system lesions and developmental scoliosis in myelomeningocele.

Hydrocephalus, spinal cord tethering, cord atresia, hydromyelia, syringomyelia and various manifestations of the Arnold-Chiari malformation occur in association with scoliosis in patients with myelomeningocele. While the causes of the cord lesions remain debatable, these lesions appear to be progressive and causally related to the scoliotic deformity. We have reviewed seventeen myelomeningocele patients with developmental scoliosis and have found that aggressive orthopaedic treatment combined with neurosurgical treatment can satisfactorily control spinal deformity in most cases. Before undertaking orthopaedic treatment of severe spinal deformities in patients with myelomeningocele a careful investigation of the central nervous system with myelography and cord and head CT scans should be carried out.

Arnold-Chiari Malformation↗
PubMed1983

Hip dislocation in cerebral palsy: selection for treatment.

Forty-five patients with cerebral palsy hip-dislocation were reviewed and it was found that some did well without treatment. For patients with hip pain, the best results were obtained with extensive resection arthroplasty: soft-tissue surgery alone was unsuccessful. Open reduction with femoral osteotomy achieved concentric reduction in all 15 patients who had this type of surgery: however, most retained their abnormal postural reflex activity to such a degree that subsequent scoliosis, pelvic obliquity, hip extension contractures and knee flexion deformities compromised the success of the hip surgery.

Adolescent↗
PubMed1983

Anterior approaches to the cervical spine.

Excellent exposure of the cervical spine from C4 to T1 can be attained with the standard anterior approach which utilizes a longitudinal or transverse incision to gain access to the anterior border of the sternocleidomastoid which, along with the trachea, esophagus, and carotid sheath, is retracted. Blunt dissection anterior to the sheath exposes the prevertebral fascia and the anterior aspect of the spine from C4 to T1. Occasionally surgery in the lower cervical spine necessitates detachment of the sternal head of the sternocleidomastoid. Anterolateral approaches to the upper cervical spine and base of the skull often require partial release of the sternocleidomastoid from the mastoid process and retraction of the carotid sheath and hypoglossal and spinal accessory nerves. If these retropharyngeal approaches do not provide sufficient access to the base of the skull and C1 and C2, a transoral approach, possibly with mandible and tongue splitting, can be useful. Infection is a consideration in transoral surgery, however, and this approach is indicated only in special circumstances.

Cervical Vertebrae↗
PubMed1983

Clinical and pathologic correlations in traumatic spondylolisthesis of the axis.

Traumatic spondylolisthesis of the axis ("hangman's fracture") occurred in an 89-year-old man who died of unrelated causes. Postmortem examination of the cervical spine revealed a correlation between the anatomic lesion and clinical treatment and prognosis. Traumatic spondylolisthesis of the axis has a high potential for union because it usually occurs through the superior facet joint, in an area of well vascularized spongy cancellous bone. Fracture through the thin cortical bone of the pars interarticularis, conversely, is predisposed to the development of a nonunion and, hence, may explain this condition. While hyperextension with compression or distraction appears to have caused the injury in some cases, axial compression with flexion was the cause in this case.

Aged↗