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Biomedical subjects

P C McCormick

Publications and source records attributed to P C McCormick.

At least 19 recordsLinked to original sources
PubMed1998

The posterior approach to a series of glomus (Type II) intramedullary spinal cord arteriovenous malformations.

OBJECTIVE: Intramedullary spinal cord arteriovenous malformations (AVMs) are comprised of those AVMs which in either glomus or nidal form are found partially or entirely within the substance of the spinal cord. An effort to subdivide these lesions into either glomus Type II or juvenile Type III spinal cord AVMs has underscored the diffuse, unresectable nature of the latter but has done little to suggest a logical management paradigm for the more well-defined, low-flow glomus lesion. METHODS: To address this shortcoming, 15 cases of glomus Type II spinal AVMs were identified from a larger series of a variety of spinal AVMs. Computed tomography, magnetic resonance imaging, and superselective angiography rendered the anatomic diagnosis of these lesions accurate in all cases. All lesions were approached posteriorly via a standard laminectomy, with the goal of total extirpation, and all patients underwent immediate postoperative angiography to verify cure. In the vast majority of cases, patients underwent follow-up imaging to confirm the durability of this cure, and long-term outcome was determined using both a subjective quality of life assay and a functional grading scale. Age, sex, mode of presentation, and radiographic features were subsequently analyzed with respect to functional outcome. RESULTS: Most glomus spinal AVMs presented with a rapid cascade of signs and symptoms (73%), often caused by subarachnoid hemorrhage (60%) and often leading to significant neurological deficits (47%). Initially, 14 of 15 patients (94%) were angiographically cured of their malformations. The remaining patient was neurologically improved after a 90% resection, and follow-up angiography demonstrated that the residual was thrombosed. However, not uncommonly, follow-up angiography and magnetic resonance imaging revealed recurrences, with three of the patients who underwent delayed imaging (23%) demonstrating new draining veins. Fortunately, in each case, the recurrence was asymptomatic. Therefore, the long-term cure rate (mean follow-up, 8.5 yr; range, 1-17 yr) was 80%, with no subsequent bleeding or progression of symptoms. Outcomes were generally good, with six patients (40%) demonstrating objective improvement, eight (53%) being neurologically stable, and one (7%) being worse. Sixty-six percent were independent, 20% required moderate assistance, and 14% remained entirely dependent. There were no deaths. Patients possessing lesions with large direct feeders off the anterior spinal artery and occupying a primarily anterior position in the cord fared somewhat worse, as did those with rapidly progressing symptomatology in the absence of subarachnoid hemorrhage. However, even in those with preserved or improved function, chronic pain was a significant problem, affecting one-third of all patients. Chronic pain was especially common in young women who had presented with significant preoperative pain that responded poorly to all subsequent therapeutic manipulations. CONCLUSION: With careful evaluation of high-quality superselective angiography and the judicious use of preoperative embolization, posterior surgical approaches can deliver results comparable with those achieved for other benign intramedullary lesions in terms of long-term cure (80%), control of symptom progression (100%), and good functional outcome (86%). Despite these results, chronic dysesthetic pain syndromes are not uncommon and continue to present a significant management problem.

Adult↗
PubMed1997

Surgical approaches to the thoracolumbar spine.

Surgical treatment of diseases involving the thoracolumbar spine offers a unique challenge to the spine surgeon. Although more familiar posterior techniques are useful for a variety of thoracolumbar problems, the management of disease in this region is often optimized by an anterior approach. Thoracolumbar surgery requires an understanding of the relevant surgical anatomy, the pathologic processes affecting this region, and the relative indications and contraindications for particular operative strategies. It is also essential to be familiar with the management of potential morbidity, methods for avoiding complications, and the selection of particular fusion techniques and instrumentation devices associated with specific operative strategies.

Diskectomy↗
PubMed1996

Management of spinal epidural hematoma after tissue plasminogen activator. A case report.

STUDY DESIGN: This case report illustrates a patient with a spontaneous epidural hematoma after tissue plasminogen activator therapy who presented 10 days after the incident with a resolving Brown-Sèquard syndrome. OBJECTIVES: The treatment of this patient involves the principles of conservative follow-up directed by an improving examination and an understanding of the pathophysiology of coagulopathy-induced spontaneous epidural bleeds. SUMMARY OF BACKGROUND DATA: The use of tissue plasminogen activator therapy for thrombolysis in patients with early acute myocardial infarction is becoming increasingly routine. Use is limited most significantly by bleeding complications. Recently, several groups have drawn attention to the neurologic complications associated with intracranial hemorrhage after tissue plasminogen activator therapy. Spontaneous spinal epidural hemorrhage has, by comparison, received little attention. The authors report the second case in the literature and the first without a history of antecedent trauma. METHODS: The onset of the painful myelopathy in this patient was missed in the acute setting because of low suspicion. When the diagnosis was made, coadministered heparin had already been discontinued without reversal, and the patient's examination had already improved. Careful follow-up by neurologic examination and magnetic resonance imaging was obtained without spinal angiography being performed. RESULTS: The patient regained his prehemorrhage neurologic status, experienced no further bleeding, and his coronary ischemia remained subclinical. CONCLUSIONS: Spinal epidural hemorrhage secondary to thrombolytic therapy is becoming increasingly common. Urgent surgical decompression is generally warranted to preserve neurologic function. In cases where the deficit is minimal or resolving, a conservative approach may be warranted with magnetic resonance imaging but not angiographic follow-up.

Aged↗
PubMed1996

Intramedullary spinal cord metastasis: report of three cases and review of the literature.

BACKGROUND: Intramedullary spinal cord metastasis is rare; but it is being encountered with increasing frequency. Optimal treatment after diagnosis remains controversial. METHODS: In the last 3 years, we have encountered three cases of intramedullary metastasis presenting as focal mass lesions with minimal systemic evidence of cancer. We present our results in these patients and review the literature in an effort to more optimally define both the natural course of this disease, as well as a potential subset of patients who might benefit from more aggressive treatment. RESULTS: With the availability of more sensitive imaging techniques, these tumors are being diagnosed with increasing frequency. Magnetic resonance imaging is sensitive, but nonspecific, in distinguishing intramedullary spinal cord metastases from primary cord tumors. Urgent biopsy is often necessary prior to definitive treatment. Radiation with chemotherapy significantly prolongs survival. Radical subtotal resection may offer additional quality survival, especially in cases of metastatic melanoma with an occult primary. CONCLUSIONS: Regardless of treatment, many patients survive less than 1 year. Intramedullary spinal cord metastasis is a devastating condition, but with appropriate diagnosis and aggressive treatment, selected patients may have substantially increased survival.

Breast Neoplasms↗
PubMed1996

Surgical management of dumbbell and paraspinal tumors of the thoracic and lumbar spine.

The lateral extracavitary approach was used for single-staged tumor resection in 12 patients with complex dumbbell or paraspinal tumors of the thoracic and lumbar spine. Six women and six men (age, 28-72 yr) were treated between August 1990 and January 1994. The tumors included schwannoma (6 patients), malignant meningioma (1 patient), hemangioma (1 patient), chondrosarcoma (1 patient), osteocartilaginous exostosis (1 patient), radiation-induced osteogenic sarcoma (1 patient), and metastatic renal carcinoma (1 patient). Gross total resection was achieved in 11 patients. Radical subtotal removal was performed in the remaining patient, who had a malignant osteogenic sarcoma. Concomitant spinal stabilization with internal fixation and anterior interbody strut grafting was performed on two patients. No significant perioperative complications occurred. Ten patients were alive and clinically stable at follow-up visits ranging from 14 to 55 months. Two patients died from systemic tumor dissemination during the follow-up period. The lateral extracavitary approach is useful when extensive or difficult spinal and paraspinal exposure is required. The surgical aspects of these neoplasms and the technique of lateral extracavitary approach are described in detail.

Adult↗
PubMed1996

Surgical management of dumbbell tumors of the cervical spine.

Twelve patients with benign dumbbell tumors of the cervical spine were treated surgically between March 1991 and July 1994. Gross total resection was achieved in 11 patients, using a single-stage modified posterior midline exposure with laminectomy and complete unilateral facetectomy. This exposure provides contiguous intraspinal, foraminal, and extraforaminal access that extends up to 4 cm from the lateral dural margin. The surgical considerations of these tumors, including the surgical technique, potential spinal instability, vertebral artery, and risk of nerve root injury, are presented.

Adult↗
PubMed1996

Atlantoaxial degenerative articular cysts.

Cysts associated with spinal joints are not a common cause of neurological symptoms. The authors report a series of five patients with cysts of the atlantodental articulation and review five additional cases from the literature. The patients ranged from 60 to 85 years of age and included three men and seven women. No patient had evidence of rheumatoid arthritis or previous trauma. The cysts caused ventral cervicomedullary compression, did not enhance on magnetic resonance imaging, and were not associated with widening of the anterior atlantodental interval or osseous degeneration of the dens. All patients improved postsurgery. Fusion was required if a transoral procedure was performed. Patients undergoing posterior decompressions were clinically and radiographically stable after operation.

Aged↗
PubMed1996

High cervical split cord malformation and neurenteric cyst associated with congenital mirror movements: case report.

A 48-year-old woman with congenital mirror movements of the hands presented with a high cervical split spinal cord malformation and a ventrally located neurenteric cyst. The clinical, radiological, and surgical features are presented. A brief discussion of the literature and embryology pertaining to split cord malformations and mirror movements is included. To our knowledge, this is the first case of radiographically and surgically proven split cord malformation associated with either mirror movements or a neurenteric cyst presenting in an adult.

Dominance, Cerebral↗
PubMed1995

Retropleural approach to the thoracic and thoracolumbar spine.

Retropleural thoracotomy was used in 15 patients for the management of ventral thoracic and thoracolumbar spine abnormalities. This approach provides the shortest direct route to the anterior thoracic spine and avoids pleural cavity entry. A detailed description of retropleural thoracotomy and the clinical experiences of 15 patients treated with it are presented.

Adult↗
PubMed1994

Anatomic principles of intradural spinal surgery.

In summary, the predominate role of surgery as the definitive treatment modality for the vast majority of intradural pathology provides a unique opportunity to improve outcome through continued advances in microsurgery. There is also, however, the added responsibility that comes with the treatment of benign and generally nonlife-threatening pathology, that is, an increasing expectation of cure and anticipation of preserved neurologic function. Successful intervention is maximized by the surgeon who recognizes that microsurgical technique and judgment are learned skills obtained only through experience but developed within a framework of anatomic principles and an understanding of how anatomy is altered by specific pathologic processes.

Arteriovenous Malformations↗
PubMed1993

Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.

Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. The spinal cord was stimulated using either epidural or subarachnoid electrodes. Compound muscle action potentials were recorded from quadriceps and tibialis anterior muscles. Well-formed, stable motor-evoked potentials were recorded in all but one patient, in whom a preexisting myelopathy was felt to preclude recording. Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.

Action Potentials↗
PubMed1993

Pregnancy and discogenic disease of the spine.

Low back pain is common during pregnancy and is of moderate or severe intensity in about one fourth of all pregnancies. The etiology is multifactorial but in most cases is related to the physical and physiologic changes brought about by pregnancy. For most women, the pain resolves spontaneously, although they remain at higher risk for increased LBP in future pregnancies and for the development of symptomatic disc disease in later life. Many of the common treatments for LBP are contraindicated or must be modified in this setting. Neurologically symptomatic herniated discs are rare during pregnancy, yet, when indicated, pregnant women can safely undergo surgery.

Diagnosis, Differential↗
PubMed1992

The treatment of associated intracranial aneurysms and arteriovenous malformations.

Cerebral arterial aneurysm associated with arteriovenous malformation (AVM) has been described with a variable incidence, averaging 10% of AVM cases. The present series includes 39 patients with this association, derived from a total of 400 patients with AVM's evaluated and treated since 1970. The aneurysms are classified into four major groups, each carrying particular therapeutic implications. Optimum treatment of these lesions is based in part on a knowledge of the hemodynamic alterations associated with the AVM's. In most of these cases, the symptomatic lesion was treated first; occasionally, when feasible, both lesions were treated during the same operation. All patients had some form of treatment, either surgical or endovascular, directed to at least one of the two types of lesions. All symptomatic lesions were treated and all ruptured aneurysms were obliterated. There were no deaths in this series.

Adolescent↗
PubMed1992

Infections of the dural spaces.

Suppuration involving the epidural and subdural spaces is a rare occurrence in modern neurosurgical practice. Early diagnosis and appropriate treatment of infections of the dural spaces may avert the high incidence of neurologic disability and death traditionally associated with them, however. Prompt neurosurgical intervention in the treatment of these lesions has been the standard with which all other therapies have been compared.

Brain Abscess↗