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Biomedical subjects

H M Clarke

Publications and source records attributed to H M Clarke.

At least 19 recordsLinked to original sources
PubMed2003

The role of the brachioradialis H reflex in the management and prognosis of obstetrical brachial plexus palsy.

The H reflex was investigated to determine if it can be useful in the prognosis of obstetrical brachial plexus palsies. The H reflex is an electrically stimulated monosynaptic or oligosynaptic response which can be recorded in peripheral nerves in all muscles of infants up to approximately two years of age. It is essentially the electrophysiologic counterpart of the deep tendon reflex, and its presence indicates intact afferent and efferent axons at the particular spinal segment. Our objectives were to document the Brachioradialis H (Br H) reflex latency and amplitude in normal upper extremities of infants, to evaluate the presence or absence of the Br H reflex in obstetrical palsy neonates and infants between one and seven months of age and to determine if this test was a valid predictor of final clinical outcome. A prospective study of 109 patients was performed to measure the Br H reflex in the affected and the contralateral normal limb. The results from the abnormal limb were compared to the final clinical decision made by nine months for or against surgical intervention. In the normal limbs, a Br H latency of 10.7 +/- 0.8 msec was determined with an amplitude of 1.2 +/- 1.2 mV. The chi 2 analysis in infants from one month to seven months old revealed a strong relationship between an absent Br H reflex and little or no clinical improvement (p < 0.0001), with a sensitivity for predicting poor outcome of 85.7%. The odds ratio (with a 95% confidence interval) of a child with an absent Br H reflex not significantly improving by nine months was 8.4 times higher than if the Br H reflex was present. The false positive rate was 42% however, indicating that a significant number of patients improved clinically, despite having a nonrecordable Br H reflex at age seven months or less. The low false negative rate of 14.3% suggested that in the presence of a Br H reflex, the majority of patients recover. Therefore, the presence of the Br H reflex is a helpful test in the prognostication of good recovery in obstetrical upper plexus palsy patients.

Birth Injuries↗
PubMed2001

Aerosolization of epidermal cells with fibrin glue for the epithelialization of porcine wounds with unfavorable topography.

Aerosolized epidermal cell suspension was previously found to be effective for the epithelialization of full-thickness wounds. This suspension is less expensive than and requires a shorter preparation time than the currently used cultured epithelial autografts. Still, convex and irregular wounds present unfavorable conditions for homogenous dispersion of the aerosolized cell suspension. The authors hypothesized that the addition of fibrin glue to the aerosol of cells would reduce cell movement and ensure homogenous dispersion of the cells, thereby promoting wound epithelialization. The objectives of the study were to evaluate the healing of wounds with unfavorable topography after autotransplantation of an epidermal cell aerosol with and without fibrin glue. Six Yorkshire piglets were studied. An epidermal suspension was made from full-thickness groin skin. Dispase was used to separate the epidermis from the dermis, and trypsin was used to separate the epidermal cells from one another. Twenty-four hours later, full-thickness wounds with unfavorable topography were created adjacent to the vertebral column of six pigs. Twelve wounds were treated with an aerosol of epidermal cell suspension mixed with fibrin glue (study group), and 12 wounds were treated with the same suspension without the fibrin glue (control group). The percentages of total wound contraction and the epithelialized and nonepithelialized areas were evaluated 1, 2, 3, and 4 weeks after aerosolization. The histologic characteristics of the newly formed skin were examined by light microscopy using slides stained with hematoxylin and eosin. Study wounds were characterized by central epithelialization, whereas control wounds were characterized by peripheral epithelialization. Study wounds contracted at a slower rate than control wounds, but wound size was the same in both groups after 4 weeks. The addition of fibrin glue facilitated epithelialization: Study wounds showed 75.5 +/- 22.4 percent (mean +/- SD) and 94.2 +/- 8.8 percent epithelialization after 3 and 4 weeks, respectively, compared with 46.3 +/- 9.5 percent and 47.9 +/- 13.1 percent epithelialization of the control wounds at the same times. These differences between the study and control groups were statistically significant (p < 0.001, paired t test). The addition of fibrin glue to an aerosol of epidermal cells significantly enhances the epithelialization of wounds with unfavorable topography in pigs.

Administration, Topical↗
PubMed2000

The prognostic value of concurrent Horner's syndrome in total obstetric brachial plexus injury.

The prognostic value of concurrent Horner's syndrome in infants with total birth palsy was investigated. The records of 48 cases with total palsy were reviewed. Poor spontaneous return of the motor function of the limb was found for both with and without concurrent Horner's syndrome. Fisher's exact test (P=0.02) indicated that the presence of concurrent Horner's syndrome is a significant prognostic factor for poor spontaneous recovery of the limb.

Brachial Plexus Neuropathies↗
PubMed2000

Predictive value of computed tomographic myelography in obstetrical brachial plexus palsy.

Preoperative radiologic studies to detect root avulsions of the brachial plexus caused by birth trauma are considered useful in assisting with surgical planning for reconstruction. In this study, the predictive value of computed tomographic (CT) myelography in detecting nerve root avulsions at our institution was determined. Sixty-three consecutive patients with an obstetrical brachial plexus palsy who had had both preoperative CT myelography and reconstructive surgery were selected. All CT myelograms were analyzed post hoc by a single neuroradiologist in a manner blind to the surgical findings. At each root level of the brachial plexus, the presence of a pseudomeningocele was noted along with the presence or absence of rootlets within each identified pseudomeningocele. Extraforaminal root avulsions later determined at surgery were reviewed by a single surgeon in a manner blind to the radiographic results. Surgical and radiographic findings were then compared at each corresponding root level. A total of 281 roots were examined. The sensitivity, specificity, positive predictive value, and likelihood ratio for root avulsions with pseudomeningoceles were 0.63, 0.85, 0.40, and 4.2, respectively. For pseudomeningoceles for which rootlets traversing the sac could not be identified, these values were 0.37, 0.98, 0.74, and 18.5, respectively. The presence of pseudomeningoceles with or without rootlets was not a sensitive indicator of root avulsions. Root avulsions were better predicted by identifying the absence of rootlets in a pseudomeningocele. This absence on CT myelography may be used to suggest an extraforaminal root avulsion due to its high specificity and high likelihood ratio.

Birth Injuries↗
PubMed2000

Increased tight junction permeability can result from protein kinase C activation/translocation and act as a tumor promotional event in epithelial cancers.

Exposure of LLC-PK1 epithelial cell cultures to phorbol ester tumor promoters causes immediate translocation of protein kinase C-alpha (PKC-alpha) from cytosolic to membrane-associated compartments. With a very similar time course, a dramatic and sustained increase in tight junctional (paracellular) permeability occurs. This increased permeability extends not only to salts and sugars but macromolecules as well. Fortyfold increases of transepithelial fluxes of biologically active EGF and insulin occur. Recovery of tight junction barrier function coincides with proteasomal downregulation of PKC-alpha. The failure to downregulate activated membrane-associated PKC-alpha has correlated with the appearance of multilayered cell growth and persistent leakiness of tight junctions. Accelerated downregulation of PKC-alpha results in only a partial and transient increase in tight junction permeability. Transfection of a dominant/negative PKC-alpha results in a slower increase in tight junction permeability in response to phorbol esters. In a separate study using rat colon, dimethylhydrazine (DMH)-induced colon carcinogenesis has been preceded by linear increases in both the number of aberrant crypts and transepithelial permeability, as a function of weeks of DMH treatment. Adenocarcinomas of both rat and human colon have been found to have uniformly leaky tight junctions. Whereas most human colon hyperplastic and adenomatous polyps contain nonleaky tight junctions, adenomatous polyps with dysplastic changes did possess leaky tight junctions. Our overall hypothesis is that tight junctional leakiness is a late event in epithelial carcinogenesis but will allow for growth factors in luminal fluid compartments to enter the intercellular and interstitial fluid spaces for the first time, binding to receptors that are located on only the basal-lateral cell surface, and causing changes in epithelial cell kinetics. Tight junctional leakiness is therefore a promotional event that would be unique to epithelial cancers.

Adenocarcinoma↗
PubMed2000

Rheumatic disorders of the hand and wrist in childhood and adolescence.

Rheumatic diseases are common in the pediatric population. Because the hand surgeon is often the first specialist to whom children with rheumatic disease involving the upper extremity are referred, it is important they are aware of the wide variety of disorders that can present with joint complaints to facilitate prompt referral and treatment of these patients.

Adolescent↗
PubMed1999

Straightening of aberrant carotid arteries with age in velocardiofacial syndrome.

Two cases of velocardiofacial syndrome demonstrated spontaneous straightening over a 4-year period of previously deviated carotid arteries on contrast enhanced computed tomography. Based on this finding, uncomplicated traditional pharyngeal flaps were performed on both patients. It is unknown whether straightening of aberrant vessels with age is the rule or the exception in this patient population.

Adolescent↗
PubMed1998

The prognostic value of concurrent phrenic nerve palsy in newborn children with Erb's palsy.

The prognostic value of concurrent phrenic nerve palsy in newborn babies with Erb's palsy was investigated. The records of 191 babies with Erb's palsy were reviewed retrospectively at two institutions. Poor spontaneous return of the motor function of the limb was found for infants both with and without concurrent phrenic nerve palsy. Concurrent phrenic nerve palsy in newborn babies with Erb's palsy has no prognostic value in predicting spontaneous motor recovery of the limb.

Arm↗
PubMed1998

Neuroma-in-continuity resection: early outcome in obstetrical brachial plexus palsy.

The short-term effect of neuroma-in-continuity resection in obstetrical brachial plexus palsy was evaluated to test the hypothesis that the neuroma does not contribute to useful limb function. Twenty-six patients with obstetrical brachial plexus palsy underwent resection of the neuroma-in-continuity and interpositional nerve grafting, and 17 patients underwent neurolysis only. The preoperative and postoperative active movement scores were recorded using an eight-point scale for 15 joint motions in each patient. Data analysis examined the change in total limb motion scores over time within patients undergoing neuroma-in-continuity resection and a comparison with those patients undergoing neurolysis. Compared with preoperative assessment, limb motion scores after neuroma resection were significantly decreased at 6 weeks, not significantly different by 3 months, and significantly improved at 12 months postoperatively. In comparison to patients undergoing neurolysis only, limb motion scores after neuroma resection were not significantly different at 3, 6, and 12 months postoperatively. These findings are unlikely to be accounted for by axonal regeneration across interpositional nerve grafts. Nerve regeneration or recovery in the nongrafted segment of the plexus must be sufficient to reproduce preoperative motion. Resection of the neuromas-in-continuity in obstetrical brachial plexus palsy does not significantly diminish motor activity.

Brachial Plexus↗
PubMed1997

Ring avulsion injuries and the basketball player.

As basketball increases in worldwide popularity, more epidemiological data on injury rate and type will be documented. A serious ring avulsion injury (Urbaniuk Class I) is here reported in an adolescent incurred while attempting a slam dunk. The management of this injury is discussed as well as safety concerns for coaches and supervisory staff.

Adolescent↗
PubMed1997

Case report: unilateral combined facial nerve and brachial plexus palsies in a neonate following a midlevel forceps delivery.

A case is described in which the 2.7-kg fetus of a nonobese primigravid patient, delivered by midlevel forceps manipulation sustained neurapraxias of both the marginal mandibular branch of the seventh cranial nerve and the upper trunks of the ipsilateral brachial plexus. The pregnancy was uneventful, but labor was complicated by an occipitoposterior presentation and a prolonged second stage. Examination of the neonate revealed bruising and skin markings consistent with injury by obstetric forceps and the anatomic location of these marks suggested that cervical and mandibular compression from the forceps, rather than traction by the accoucheur, would account for the observed findings. A review of the English language literature over the past 30 years revealed only four cases in which a combination of facial nerve and brachial plexus injuries could both be linked to obstetric instrumentation.

Adult↗
PubMed1996

Extremity gangrene in utero.

A neonate with extremity gangrene resulting from intrauterine embolization of infarcted placental substances is discussed. This rare clinical entity is thought to be most commonly a manifestation of embolic phenomenon during maturation of the neonatal circulatory system. Management of neonatal gangrene is conservative, delaying amputation as long as possible since the line of demarcation tends to migrate distally. Evidence of multiple emboli should be carefully sought prior to definitive treatment.

Arm↗
PubMed1996

Obstetrical brachial plexus palsy: results following neurolysis of conducting neuromas-in-continuity.

Sixteen infants with conducting neuromas-in-continuity at primary brachial plexus exploration underwent microsurgical neurolysis of their lesions. For each patient, the immediate preoperative scores for individual joint movements were compared with scores at the last examination. In the Erb's palsy group (n = 9), significant improvement was seen in shoulder movements, elbow flexion, supination, and wrist extension (paired t test, p < 0.05). Clinically useful improvements in function was seen at the shoulder and elbow (Fisher's exact test, p < 0.05). In the total palsy group (n = 7), significant improvement in shoulder abduction, shoulder adduction, elbow flexion, and extension of the wrist, fingers, and thumb was seen (paired t test, p < 0.05), but there was no significant improvement in the proportion of patients with useful functional outcomes. Neurolysis in Erb's palsy improves both muscle grade and the functional ability of patients. Neurolysis does not provide useful functional recovery in patients with total plexus palsy.

Brachial Plexus↗
PubMed1996

Endoscopic sural nerve harvest in the pediatric patient.

A technique of endoscopic sural nerve harvest was devised to minimize the donor-site scarring in pediatric patients requiring peripheral nerve-grafting procedures. The harvests were performed under tourniquet control using two 2-cm incisions for access at the lateral malleolus and the midcalf. Endoscopic visualization and blunt dissection of the nerve were achieved with a 4-mm Hopkins telescope with 30-degree angled lens (Karl Storz GmbH, Tuttlingen, Germany) stabilized in an Emory retractor and attached to a video camera. The medial sural nerve was divided in the popliteal fossa proximally under endoscopic visualization. The lateral sural nerve was identified and harvested when present. Between June of 1994 and March of 1995, 18 patients underwent 27 sural nerve harvests using the endoscopic technique. Mean patient age was 3.3 years (range 4 to 197 months). Indications for surgery included obstetrical brachial plexus palsy (12), facial palsy (5), and ulnar nerve neuroma (1). Nerve-graft length harvested ranged from 13 to 41 cm. Mean tourniquet time per limb was 92 minutes. No nerve graft injury was noted on examination under the operating microscope. Postoperative pain, swelling, and ecchymosis were minimal. Donorsite scarring has been aesthetically satisfactory to date.

Adolescent↗