Biomedical subjects

Lisa B E Shields

Publications and source records attributed to Lisa B E Shields.

16 recordsLinked to original sources

PubMed2006

Adverse effects associated with high-dose recombinant human bone morphogenetic protein-2 use in anterior cervical spine fusion.

STUDY DESIGN: A retrospective review of patients who underwent an anterior cervical fusion using recombinant human bone morphogenetic protein (rhBMP)-2 with an absorbable collagen sponge (INFUSE; Medtronic Sofamor Danek, Minneapolis, MN). OBJECTIVE: To ascertain the complication rate after the use of high-dose INFUSE in anterior cervical fusions. SUMMARY OF BACKGROUND DATA: The rhBMP-2 has been primarily investigated in lumbar spine fusions, where it has significantly enhanced the fusion rate and decreased the length of surgery, blood loss, and hospital stay. METHODS: We present 151 patients who underwent either an anterior cervical discectomy and fusion (n = 138) or anterior cervical vertebrectomy and fusion (n = 13) augmented with high-dose INFUSE between July 2003 and March 2004. The rhBMP-2 (up to 2.1 mg/level) was used in the anterior cervical discectomy and fusions. RESULTS: A total of 35 (23.2%) patients had complications after the use of high-dose INFUSE in the cervical spine. There were 15 patients diagnosed with a hematoma, including 11 on postoperative day 4 or 5, of whom 8 were surgically evacuated. Thirteen individuals had either a prolonged hospital stay (> 48 hours) or hospital readmission because of swallowing/breathing difficulties or dramatic swelling without hematoma. CONCLUSIONS: A significant rate of complications resulted after the use of a high dose of INFUSE in anterior cervical fusions. We hypothesize that in the cervical area, the putative inflammatory effect that contributes to the effectiveness of INFUSE in inducing fusion may spread to adjacent critical structures and lead to increased postoperative morbidity. A thorough investigation is warranted to determine the optimal dose of rhBMP-2 that will promote cervical fusion and minimize complications.

Adult↗

PubMed2006

Objective assessment of cervical spinal cord injury levels by transcranial magnetic motor-evoked potentials.

BACKGROUND: The neurologic examination serves as the optimal method to record the level of spinal cord injury (SCI). However, this test is subject to interexaminer variability. To address this shortcoming, we describe a technique that uses transcranial magnetic motor-evoked potentials (tcMMEPs) and dermatomal somatosensory-evoked potentials (d-SSEPs) to more accurately measure the precise level of SCI. METHODS: Two groups of subjects were studied: (1) complete cervical SCI (n = 10) and (2) neurologically intact volunteers (n = 10). Two additional patients were evaluated: one with a cervical central spinal cord syndrome and another with a head injury with a suspected cervical SCI. Each subject underwent upper extremity tcMMEPs and d-SSEPs. RESULTS: Transcranial magnetic motor-evoked potentials were elicited from all upper limb myotomes (C4-T1, bilaterally) in neurologically intact volunteers (20 sides). The level of injury was determined using tcMMEPs by observing the lowest level of measurable response. The level of injury obtained using tcMMEPs was the same as that determined by neurologic examination in 13 (65%) of the 20 sides. In 7 sides, tcMMEP responses were obtained 1 level lower than that assessed by physical examination. Dermatomal somatosensory-evoked potentials were obtained from all dermatomes of volunteers tested in the laboratory compared with only 5 of the 9 patients with SCI who underwent d-SSEP testing. CONCLUSION: Testing using tcMMEPs provides an objective supplement to the neurologic examination after acute cervical SCI. Dermatomal somatosensory-evoked potentials were of limited value in determining the level of cervical SCI.

Adolescent↗

PubMed2006

Dural repair reduces connective tissue scar invasion and cystic cavity formation after acute spinal cord laceration injury in adult rats.

This study examined whether duraplasty after acute cervical laceration spinal cord injury (SCI) in a rat model could (1) improve cerebrospinal fluid (CSF) circulation adjacent to the injury; (2) minimize connective tissue scarring; and (3) reduce post-traumatic inflammation and cystic cavitation. Following a transverse dural/arachnoid incision and C5-6 dorsal spinal hemisection, a 5-mm2 cadaveric dura mater allograft was placed over the lesion and fixed with fibrin glue (n=12). Control animals received an identical dural/arachnoid incision and cervical dorsal hemisection without dural repair (n=12). At 1, 5, and 10 weeks post-injury, plain film myelograms were obtained to characterize CSF circulation, and stereological methods were used to compare the extent of tissue sparing between the two groups. Immunohistochemical studies were performed to assess the degree of inflammation (ED-1), connective tissue scarring (laminin and type IV collagen), and reactive astrogliosis (GFAP). Our results indicate that dural allograft can improve CSF flow adjacent to the site of injury, which may be due to reduced meningeal fibrosis/scarring at the lesion site. Stereological analysis demonstrated that duraplasty resulted in a significant reduction in lesion volume at each time-point (p<0.01) associated with a nearly complete attenuation of post-traumatic cystic cavitation (p<0.001). Immunofluorescence studies demonstrated that duraplasty reduced the infiltration of ED-1-positive macrophages/microglia into and surrounding the lesion site, which may be responsible for the marked reduction in secondary injury following duraplasty. We conclude that duraplasty following acute spinal cord laceration may (1) improve CSF flow by limiting meningeal fibrosis; (2) reduce connective tissue scar formation; and (3) attenuate macrophage accumulation and progressive secondary injury.

Acute Disease↗

PubMed2006

Toxicologic findings in suicide: a 10-year retrospective review of Kentucky medical examiner cases.

Toxicologic analysis is an integral component in the investigation of suicide and requires correlation with a detailed scene inspection, with an extensive exploration into the decedent's medical and social background to uncover suicidal ideation or intent and a postmortem examination of the body. In this review, the authors analyzed 2864 cases classified as suicide upon autopsy and toxicologic examinations between 1993 and 2002 in the Kentucky Division of Medical Examiner's Services. Blood and urine were collected in 95.0% and 72.3% of cases, respectively. A total of 32.5% of the victims had negative blood toxicologic results, and 52.7% of urine toxicology screens yielded no drugs. Analysis of the data indicated that 3 times as many women had taken antidepressants and more than twice as many had consumed opioids. Drug toxicity ("overdose") ranked as the third (9.9%) leading cause of suicide after firearm injury (67.5%) and hanging (13.7%). Women succumbed to drug toxicity more than men (27.5% versus 5.9%). Of the overdose deaths, 66.5% had a negative blood alcohol concentration (BAC), while antidepressants, opioids, and benzodiazepines were detected in blood in 54.4%, 37.4%, and 29.2% of the subjects, respectively. The collection of these data serves the goals of public health and clinicians in devising strategies for suicide prevention.

Adolescent↗

PubMed2006

Adolescent and young adult suicide: a 10-year retrospective review of Kentucky Medical Examiner cases.

The compilation of all suicidal causes of death attained the third highest ranking of mortality between the ages of 15 and 24 following unintentional deaths and homicide in the United States, accounting for approximately 4000 deaths in 2002. A variety of biopsychosocial factors may contribute to adolescent suicidal behavior, including psychiatric disorders, risk-taking behaviors, and lack of a cohesive family unit. The authors conducted a 10-year (1993-2002) retrospective review of 108 Medical Examiner cases of suicide ages 11-17 and 358 cases ages 18-24 in Kentucky, which represents two thirds of the Coroner cases in the state. The majority of victims were male and Caucasian. The major causes of death were the same for the two age groups, specifically, firearm injury (72.2% and 70.7%), hanging (22.2% and 18.7%), and drug intoxication (2.8% and 5.3%). An integrated Coroner-Medical Examiner system profits in the public health arena by providing collaborative research data for policy decisions. The prevalence of youth suicide by firearm should prompt further discussion regarding ways to better identify high-risk adolescents and young adults and restrict pediatric access to unsecured household firearms.

Adolescent↗

PubMed2005

Atypical autoerotic death: part II.

Autoerotic fatalities encompass a wide array of means and mechanisms used to attain sexual gratification. The most commonly encountered autoerotic practice, specifically, autoerotic asphyxia, denotes death resulting from failure of a release mechanism of the apparatus designed to attain cerebral hypoxia for heightened arousal. Historically, the majority of victims of autoerotic death are Caucasian males under the age of 30. While autoerotic death is most often associated with a constrictive cervical ligature tied to either other parts of the victim's body or to an inanimate object such as a door, several other methods have been reported. These modalities include ligature around the thorax or abdomen, plastic bags covering the face, electrical current, inhalation of a toxic gas or chemicals, or partial or total submersion, known as aquaerotic asphyxiation. This study highlights 11 cases of atypical autoerotic death, including asphyxia with a plastic bag, electrocution, and inhalation of butane and nitrous oxide (N2O). Whereas the manner of death in the majority of autoerotic death cases is deemed accidental, we present and analyze unique and equivocal cases representing 4 different manners of death: accident, natural, suicide, and homicide. The 11 victims were all Caucasian and between the ages of 17 and 55. Ten decedents were males, 1 female. A comprehensive investigation incorporating a thorough scene analysis, gathering of the victim's history, and complete postmortem examination is necessary to elucidate both the cause and manner of death in these atypical cases.

Adolescent↗

PubMed2005

Autoerotic asphyxia: part I.

Fatal autoerotic asphyxia refers to death during solitary sexual activity with self-induced asphyxiation meant to be brief and reversible. However, an unexpected fatality results from a failure of a release mechanism apparatus. The large majority of victims of autoerotic death are Caucasian males between the second and fourth decade. While autoerotic death may encompass a myriad of other means of achieving sexual gratification, which includes asphyxia by plastic bag or inhalation of noxious chemicals, the most common method is by ligature about the neck. This study presents a 9-year retrospective review of deaths due to autoerotic asphyxia, specifically ligature asphyxia, in Kentucky between 1993 and 2001. Of the sixteen victims, all were Caucasian males between the ages of 14 and 59 years, with a mean age of 38.3 years. Cross-dressing was a feature in 4 cases. A thorough review of the decedent's background, meticulous scene investigation, and complete postmortem examination may shed light on the mechanism and psychosocial predisposition associated with autoerotic asphyxia.

Adolescent↗

PubMed2005

Risk factors associated with sudden unexplained infant death: a prospective study of infant care practices in Kentucky.

OBJECTIVE: To ascertain the prevalence of infant care practices in a metropolitan community in the United States with attention to feeding routines and modifiable risk factors associated with sudden unexplained infant death (specifically, prone sleeping position, bed sharing, and maternal smoking). METHODS: We conducted an initial face-to-face meeting followed by a telephone survey of 189 women who gave birth at a level I hospital in Kentucky between October 14 and November 10, 2002, and whose infants were placed in the well-infant nursery. The survey, composed of questions pertaining to infant care practices, was addressed to the women at 1 and 6 months postpartum. RESULTS: A total of 185 (93.9%) women participated in the survey at 1 month, and 147 (75.1%) mothers contributed at 6 months. The racial/ethnic composition of the study was 56.1% white, 30.2% black, and 16.4% biracial, Asian, or Hispanic. More than half of the infants (50.8%) shared the same bed with their mother at 1 month, which dramatically decreased to 17.7% at 6 months. Bed sharing was significantly more common among black families compared with white families at both 1 month (adjusted odds ratio [OR]: 5.94; 95% confidence interval [CI]: 2.71-13.02) and 6 months (adjusted OR: 5.43; 95% CI: 2.05-14.35). Compared with other races, white parents were more likely to place their infants on their back before sleep at both 1 and 6 months. Black parents were significantly less likely to place their infants on their back at 6 months compared with white parents (adjusted OR: 0.14; 95% CI: 0.06-0.33). One infant succumbed to sudden infant death syndrome at 3 months of age, and another infant died suddenly and unexpectedly at 9 months of age. Both were bed sharing specifically with 1 adult in the former and with 2 children in the latter. CONCLUSIONS: Bed sharing and prone placement were more common among black infants. Breastfeeding was infrequent in all races. This prospective study additionally offers a unique perspective into the risk factors associated with sudden infant death syndrome and sudden unexplained infant death associated with bed sharing by examining the survey responses of 2 mothers before the death of their infants combined with a complete postmortem examination, scene analysis, and historical investigation.

Adolescent↗

PubMed2005

The therapeutic window for spinal cord decompression in a rat spinal cord injury model.

OBJECT: There are no clinically based guidelines to direct the spine surgeon as to the proper timing to undertake decompression after spinal cord injury (SCI) in patients with concomitant stenosis-induced cord compression. The following three factors affect the prognosis: (1) severity of SCI; (2) degree of extrinsic spinal cord compression; and (3) duration of spinal cord compression. METHODS: To elucidate further the relationship between varying degrees of spinal stenosis and a mild contusion-induced SCI (6.25 g-cm), a rat SCI/stenosis model was developed in which 1.13- and 1.24-mm-thick spacers were placed at T-10 to create 38 and 43% spinal stenosis, respectively. Spinal cord damage was observed after the stenosis-SCI that was directly proportional to the duration of spinal cord compression. The therapeutic window prior to decompression was 6 and 12 hours in the 43 and 38% stenosis-SCI lesions, respectively, to maintain locomotor activity. A significant difference in total lesion volume was observed between the 2-hour and the delayed time(s) to decompression (38% stenosis-SCI, 12 and 24 hours, p < 0.05; 43% stenosis-SCI, 24 hours, p < 0.05) indicating a more favorable neurological outcome when earlier decompression is undertaken. This finding was further supported by the animal's ability to support weight when decompression was performed by 6 or 12 hours compared with 24 hours after SCI. CONCLUSIONS: Analysis of the findings in this study suggests that early decompression in the rat improves locomotor function. Prolongation of the time to decompression may result in irreversible damage that prevents locomotor recovery.

Animals↗

PubMed2005

Suicide: a ten-year retrospective review of Kentucky medical examiner cases.

Suicide, a manner of death, ranked as the eleventh leading cause of death in the United States and accounted for approximately 30,000 deaths in 2001. A host of biological and psychosocial components interplay in a suicide investigation. Precipitating factors may include domestic quarrels, loss of employment, financial difficulties, substance abuse, chronic disease, or mental illness. The authors conducted a ten-year (1993--2002) retrospective review of suicide from all Medical Examiners' Offices in Kentucky. There were 2,864 suicides ranging between 11 and 96 years (average age 42.0 years). The majority of victims were males (81.7%) and Caucasian (94.8%). African-American females comprised the smallest group, consisting of only 0.59%. The preferred mode of death was by firearm (67.5%), followed by hanging (13.7%), overdose (9.9%), and carbon monoxide poisoning (4.4%). This comprehensive study discusses the trends of suicide in the United States during the twentieth century and underscores the importance of a multidisciplinary approach to the investigation and prevention of suicide.

Adolescent↗

PubMed2004

Dural closure, cord approximation, and clot removal: enhancement of tissue sparing in a novel laceration spinal cord injury model.

OBJECT: Laceration-induced spinal cord injury (SCI) results in the invasion of a connective tissue scar, progressive damage to the spinal cord due to complex secondary injury mechanisms, and axonal dieback of descending motor pathways. The authors propose that preparation of the spinal cord for repair strategies should include hematoma removal and dural closure, resulting in apposition of the severed ends of the spinal cord. Such procedures may reduce the size of the postinjury spinal cord cyst as well as limit scar formation. METHODS: Using a novel device, the Vibraknife, the authors created a dorsal hemisection of the spinal cord at C-6 in the adult rat. In Group 1 (eight rats), the dura mater was repaired with apposition of the two stumps of the spinal cord to reduce the lesion gap. In Group 2 (10 rats), the dura was not closed and the two cord stumps were not approximated. All rats were killed at 4 weeks postinjury, and the spinal cords from each group were removed and examined using histological, stereological, and immunohistochemical methods. In Group 1 rats a significant reduction of the total lesion volume and connective tissue scar was observed compared with those in Group 2 (Student t-test, p < 0.05). Approximation of the stumps did not promote the regeneration of corticospinal tract fibers or sensory axons through the lesion site. CONCLUSIONS: Apposition of the severed ends of the spinal cord by dural closure reduces the lesion gap, cystic cavitation, and connective tissue scar formation. These outcomes may collectively reduce secondary tissue damage at the injury site and shorten the length of the lesion gap, which will facilitate transplantation-mediated axonal regeneration after laceration-induced SCI.

Animals↗

PubMed2004

Abuse and neglect: a ten-year review of mortality and morbidity in our elders in a large metropolitan area.

Elder abuse and neglect refers to an act or omission resulting in harm, including death, or threatened harm to the health or welfare of an elderly person. Between one and two million elderly Americans experience some form of mistreatment annually. A ten-year (1992-2001) retrospective case review of morbidity and mortality among elders (age > 60 years) was conducted at a State Medical Examiner's Office serving a major metropolitan region in Kentucky and Indiana. This study addresses cases of two categories: 1) medicolegal autopsies and 2) examinations of living subjects pursuant to a Clinical Forensic Medicine Program. The authors present 74 postmortem cases, in which 52 deaths were attributed to a homicidal act and 22 deaths were suspicious for neglect. Of the 22 living victims of elder abuse and neglect, 19 cases constituted physical and/or sexual assault and three individuals suffered from neglect. This study summarizes the characteristic features of elder abuse in both postmortem and living cases and underscores the necessity for multi-agency collaboration in order to reach an accurate conclusion in case work. Policies established by a well-established elder abuse task force promote the collaborative interaction necessary to formulate criteria for prevention of abuse and death within this vulnerable population.

Aged↗

PubMed2003

Nonterrorist suicidal deaths involving explosives.

Suicidal deaths involving explosives unconnected to terrorism are rare. The investigation of deaths from explosive devices requires a multidisciplinary collaborative effort, as demonstrated in this study. Reported are 2 cases of nonterrorist suicidal explosive-related deaths with massive craniocerebral destruction. The first case involves a 20-year-old man who was discovered in the basement apartment of his father's home seconds after an explosion. At the scene investigators recovered illegal improvised power-technique explosive devices, specifically M-100s, together with the victim's handwritten suicide note. The victim exhibited extensive craniofacial injuries, which medicolegal officials attributed to the decedent's intentionally placing one of these devices in his mouth. The second case involves a 46-year-old man who was found by his wife at his home. In the victim's facial wound, investigators recovered portions of a detonator blasting cap attached to electrical lead wires extending to his right hand. A suicide note was discovered at the scene. The appropriate collection of physical evidence at the scene of the explosion and a detailed examination of the victim's history is as important as documentation of injury patterns and recovery of trace evidence at autopsy. A basic understanding of the variety of explosive devices is also necessary. This investigatory approach greatly enhances the medicolegal death investigator's ability to reconstruct the fatal event as a means of separating accidental and homicidal explosive-related deaths from this uncommon form of suicide.

Adult↗

PubMed2003

Iatrogenic catheter-related cardiac tamponade: a case report of fatal hydropericardium following subcutaneous implantation of a chemotherapeutic injection port.

The need to obtain dependable access to the vascular system constitutes a significant component in the treatment and management of critically ill patients. Intravenous chemotherapy administered to cancer patients over an extended period of time often results in loss of peripheral vascular access due to vein sclerosis, "exhaustion" or tissue necrosis. Medical investigators have designed and steadily upgraded a variety of devices constructed to improve venous access for long-term utilization. As with the introduction of any foreign object into the body, each of these devices has complications which may be life threatening and occasionally fatal. We present an unusual case of iatrogenic acute hydropericardium and cardiac tamponade caused by the percutaneous infusion of chemotherapeutic fluid via a right subclavian central venous implant system (Port-a-Cath). Failure to implant and monitor the device with a radiograph following placement according to manufacturer's guidelines and accepted standards of medical practice were causally related to an unusual complication, namely, perforation of the right cardiac ventricle by the catheter tip, resulting in sudden and unexpected cardiac death.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

Sudden unexpected death in epilepsy: neuropathologic findings.

Sudden unexpected death in epilepsy refers to sudden death of an individual with a clinical history of epilepsy, in whom a postmortem examination fails to uncover a gross anatomic, toxicologic, or environmental cause of death. Evidence of terminal seizure activity may not be present. One to two percent of natural deaths certified by the medicolegal death investigator are attributed to epilepsy. Detailed microscopic examination of the brain has increasingly afforded the identification of structural changes representative of epileptogenic foci. The authors present 70 cases of death attributed to sudden unexpected death in epilepsy. These cases were classified as follows: individuals who lacked a gross brain lesion, those who had a brain lesion demonstrable at autopsy, and those who lacked neuropathologic evaluation because of decomposition or because only an external examination was done. All of the subjects had a clinical history of seizures. The authors confirm that various microscopic findings, including neuronal clusters, increased perivascular oligodendroglia, gliosis, cystic gliotic lesions, decreased myelin, cerebellar Bergmann's gliosis, and folial atrophy, are present in a higher percentage of the brains of sudden unexpected death in epilepsy subjects than in the brains of age- and sex-matched control subjects.

Adolescent↗

PubMed2002

R. Glen spurling: surgeon, author, and neurosurgical visionary.

Doctor Roy Glenwood Spurling (1894-1968) stands as a prominent figure in the field of neurosurgery. His innovative contributions have left an indelible mark, particularly in the treatment of lumbar and cervical intervertebral disc diseases and peripheral nerve injuries. He was instrumental in founding the Harvey Cushing Society (later renamed the American Association of Neurological Surgeons) and the American Board of Neurological Surgery. Spurling was a major participant in the military during World War II; he was stationed at Walter Reed Hospital and in the European Theater, and later became well known for his care of General George S. Patton. Glen Spurling is a role model to a younger generation of neurosurgeons for his tireless effort toward the advancement of neurosurgery.

History, 20th Century↗