Biomedical subjects

Bernard H Guiot

Publications and source records attributed to Bernard H Guiot.

10 recordsLinked to original sources

PubMed2006

Transoral vertebroplasty for renal cell metastasis involving the axis: case report.

STUDY DESIGN: Case report. OBJECTIVE: This is one of the first reported cases of transoral vertebroplasty for a solid metastatic tumor at C2 body. SUMMARY OF BACKGROUND DATA: Percutaneous vertebroplasty has gained popularity as a treatment option for painful neoplastic lesions of the spine. The technique has been useful in reducing pain and stabilizing the spinal segment that is vulnerable to fracture. However, there is very little experience with vertebroplasty in the cervical spine and, more specifically, at C2. METHODS: We present a case of metastatic renal cell carcinoma of the C2 body. The patient, a 61-year-old woman, presented with an excruciating neck pain. Diagnostic workup revealed the presence of tumor in the right kidney. Multiple spinal levels were involved in addition to C2, and the C2 lesion was treated for palliative purpose. Under biplanar fluoroscopy, a vertebroplasty trocar was placed transorally into the central portion of the C2 body, and polymethyl methacrylate was injected. RESULTS: The transoral vertebroplasty achieved complete pain relief and enhanced stability of an extensive osteolytic lesion involving the C2 body. CONCLUSIONS: This minimal access procedure was effective in completely relieving pain from a metastatic deposit at C2, while adequately stabilizing the vulnerable segment by the injection of polymethyl methacrylate. The transoral route requires meticulous fluoroscopic control to prevent the leakage of polymethyl methacrylate but provides the most direct access to the C2 body.

Axis, Cervical Vertebra↗

PubMed2006

Intracranial hypotension with spinal pathology.

BACKGROUND CONTEXT: Intracranial hypotension (IH) is a syndrome in which volume depletion of the cerebrospinal fluid (CSF) results in various neurological symptoms. Most commonly, a small tear or defect in the spinal dural sac is the underlying lesion that results in a CSF leakage and IH. Causes of IH can be classified as 1) spontaneous (primary), and 2) secondary. Knowledge of IH is essential to spine surgeons, because a small proportion of patients with spontaneous IH require spine surgery, and secondary causes of IH include spine trauma, various spine-related diagnostic/therapeutic procedures (iatrogenic), and degenerative spine disorders. PURPOSE: The purpose of this review is to update knowledge of IH pertinent to spine surgery. STUDY DESIGN/SETTING: Review of the literature. METHODS: A systematic review of the literature was conducted using PUBMED. The literature regarding IH with spinal pathology published from 1966 to 2005 was searched and reviewed comprehensively. RESULTS/CONCLUSIONS: The lower cervical and upper thoracic spine are the predilection sites for a CSF leak in patients with spontaneous IH. Mechanical stress may have a role in the pathogenesis of spontaneous IH, and meningeal diverticula and connective tissue disorders may be important risk factors. Iatrogenic causes of IH include lumbar puncture, spine surgery, and chiropractic manipulation. Rarely, degenerative spine disorders are the secondary cause of IH. Although orthostatic headache is the characteristic symptom of IH, a small proportion of patients present with neck pain or radicular symptoms of the upper extremity. Imaging studies of the spine have contributed significantly to elucidation of the pathophysiology of IH as well as identification of the site of a CSF leak. Typical spinal radiographic findings of IH include extra-arachnoid or extradural fluid collections, meningeal enhancement, engorgement of the epidural venous plexus, and tonsilar descent into the foramen magnum. Most patients with spontaneous IH respond favorably to conservative management, including autologous epidural blood patch. Surgical intervention is reserved for those who fail the conservative management. Although immediate clinical improvement is usually achieved by surgery, the long-term outcomes of surgical patients need to be investigated further. In patients who have a secondary cause of IH, treatment of the underlying lesion or condition may terminate a CSF leak and result in reversal of symptoms.

Humans↗

PubMed2006

Vertebral artery injury after blunt cervical trauma: an update.

BACKGROUND: Vertebral artery injury (VAI) after blunt cervical trauma has been considered to be rare. The incidence of VAI has increased dramatically within the last decade after a heightened awareness of this entity on the part of spine surgeons. Diagnostic or therapeutic guidelines for VAI have not been established fully, however. METHODS: A review of the literature published between 1990 and 2004 was conducted. RESULTS: The incidence of VAI among total blunt trauma admissions ranged from 0.20% to 0.77%. Most VAI patients remained asymptomatic, but sudden unexpected deterioration was often reported. Distraction/extension, distraction/flexion, and lateral flexion injuries were the major mechanisms of injury. Dissection and occlusion were the frequent vascular injury patterns. Facet joint dislocations and the fractures extending into the transverse foramen were the spine injury patterns closely associated with VAI. Digital subtraction angiography was the most sensitive imaging study, but because of invasiveness, its role as a screening study remained questionable. Neuroradiological intervention was used successfully to treat hemorrhagic VAI and progressing vertebrobasilar stroke. Systemic anticoagulation with heparin was the preferred treatment for mild ischemia. Treatment of asymptomatic patients has been controversial because the natural history of VAI has not been elucidated. Prophylactic anticoagulation with heparin or the use of antiplatelet agents was advocated in recent studies. CONCLUSIONS: Preemptive treatment may be reasonable in selected patients considering the devastating potentials of VAI. The potential risks of heparin or antiplatelet agents in relation to early cervical spine surgery have not been addressed fully, however, and spine surgeons have to weigh the risk and benefit of such treatment cautiously.

Angiography, Digital Subtraction↗

PubMed2006

Vertebral hemangioma symptomatic during pregnancy treated by posterior decompression, intraoperative vertebroplasty, and segmental fixation.

Hemangioma is one of the most common benign tumors of the spine, and it remains silent in the vast majority of the subjects afflicted. Pregnancy is a known risk factor for symptomatic conversion of the previously dormant vertebral hemangiomas. However, the occurrence is rare with only 24 cases reported in the literature. The authors present a case of vertebral hemangioma symptomatic during the third trimester of pregnancy. The patient, a 20-year-old woman in her 33rd week of pregnancy, initially presented with acute back and bilateral leg pain, and developed the cauda equina syndrome within a week of its onset. Imaging studies revealed an L2 vertebral hemangioma, and the thecal sac was severely compressed by the epidural portion of the tumor. Emergency decompression and reconstruction surgery was undertaken 3 days after an uneventful cesarean section. The combined surgical management, consisting of laminectomy, intraoperative vertebroplasty, and segmental fixation, afforded adequate decompression, instant mechanical stability of the spine, and prompt pain elimination. The long-term efficacy of this combined treatment is unclear and needs to be followed cautiously.

Adult↗

PubMed2006

Ossification of the posterior longitudinal ligament: an update on its biology, epidemiology, and natural history.

Significant progress has been achieved in basic research during the past decade on the pathogenesis of ossification of the posterior longitudinal ligament (OPLL), a multifactorial disease in which complex genetic and environmental factors interact. A review of the literature was conducted to update recent findings on the biology, epidemiology, natural history, and related diseases of OPLL. Gene analysis studies found specific polymorphisms that may be associated with OPLL in several collagen genes, which encode for extracellular matrix proteins. Polymorphisms in the nucleotide pyrophosphate gene, which is involved in regulation of calcification in chondrocytes, may also be associated with OPLL. However, the results of the gene analysis studies have not always been consistent. Involvement of many growth factors and cytokines, including bone morphogenic proteins and transforming growth factor-beta, has been demonstrated in various histochemical and cytochemical analyses. Several transcription factors involved in cellular differentiation may also have a role. Recent epidemiological studies reaffirmed an earlier finding that diabetes mellitus is a distinct risk factor for OPLL. The long-term follow-up studies of OPLL patients are disclosing the natural history, as well as the frequency and rate of progression, of OPLL after surgical intervention. Further knowledge on the factors responsible for progression of OPLL may predict its behavior in each patient, and treatment may be tailored accordingly. The coexistence of OPLL with other diseases of ectopic ossification of the spine, such as ossification of the ligamentum flavum and diffuse idiopathic skeletal hyperostosis, is not uncommon. Scientific breakthrough in those diseases may, in turn, give insights into the pathogenesis of OPLL.

Animals↗

PubMed2006

A review of factors predictive of surgical outcome for ossification of the ligamentum flavum of the thoracic spine.

OBJECT: Ossification of the ligamentum flavum (OLF) is a pathological condition that affects the ligament and causes slowly progressive myeloradiculopathy in adults. Although OLF has been regarded as endemic to East Asian countries, studies from outside these areas have increasingly been reported. Because of long-standing compression of the spinal cord by OLF, a patient's functional prognosis may not always be favorable, and attempts have been made in recent studies to identify clinical factors that are predictive of the surgical outcome of patients with thoracic OLF. METHODS: The authors conducted a review of the literature published in the English, Japanese, and Korean languages. They examined studies in which correlation between clinical factors and outcome was statistically evaluated. The clinical factors included sex, age, level of the ossified ligamentum flavum, number of segments affected by OLF, coexisting ossification of the posterior longitudinal ligament (OPLL) or other spinal disorders, preoperative duration of symptoms, preoperative neurological score, computed tomography (CT)-based classification, and the presence of intramedullary high signal intensity on T2-weighted magnetic resonance images. CONCLUSIONS: The clinical factors that are unlikely to be predictive of outcome include sex, age, level of the ossified lesion, number of OLF-affected segments, coexisting OPLL, CT classification, and the presence of high signal intensity. It is unclear whether the preoperative duration of symptoms or neurological score is predictive of outcome because the results have been inconsistent among the studies. Analysis of the more recent literature, however, suggests that these two factors are predictive of outcome. The use of a neurological score should be standardized so that compilation and comparison of data can be facilitated.

Humans↗

PubMed2005

Iatrogenic carotid artery injury in neurosurgery.

Iatrogenic carotid artery injury (CAI) results from various neurosurgical procedures. A review of the literature was conducted to provide an update on the management of this potentially devastating complication. Iatrogenic CAIs are categorized according to each diagnostic or therapeutic procedure responsible for the injury, i.e., anterior cervical spine surgery, central venous catheterization, chemical substances, chiropractic manipulation, diagnostic cerebral angiography, middle-ear surgery, percutaneous procedures for trigeminal neuralgia, radiation therapy, skull-base surgery, tracheostomy, and transsphenoidal surgery. The incidence, mechanisms of injury, diagnostic imaging modalities, and reparative procedures are discussed for each procedure. Iatrogenic CAI may be more prevalent than had previously been thought, mostly because of a heightened awareness on the part of physicians and the earlier detection of asymptomatic patients owing to sophisticated and less-invasive imaging modalities. Prevention is the best treatment for every iatrogenic injury, and it is expected that further accumulation of experience with and knowledge of iatrogenic CAI will result in further reduction of this complication. Although some CAIs, such as radiation-induced carotid artery stenosis, may not be preventable, earlier intervention before the patient becomes symptomatic may favorably alter the prognosis. Following the rapid development of endovascular techniques in recent years, surgically inaccessible lesions can be treated in a more reliable and safe manner than before.

Carotid Artery Injuries↗

PubMed2003

Bone grafting.

In recent years our understanding of spinal fusion biology has improved. This includes the continued elucidation of the step-by-step cellular and molecular events involved in the prototypic bone induction cascade, as well as the identification and characterization of the various critical growth factors governing the process of bone formation and bone graft incorporation. Based on these fundamental principles, growth factor technology has been exploited in an attempt to improve rates of spinal fusion, and promising results have been realized in preclinical animal studies and initial clinical human studies. In this article the authors review the recent advances in the biology of bone fusion and provide a perspective on the future of spinal fusion, a future that will very likely include increased graft fusion rates and improved patient outcome as a result of the successful translation of fundamental bone fusion principles to the bedside.

Animals↗

PubMed2002

A minimally invasive technique for decompression of the lumbar spine.

STUDY DESIGN: The technical feasibility of percutaneous microendoscopic bilateral decompression of lumbar stenosis via a unilateral approach was evaluated in a human cadaver model. OBJECTIVES: The purpose of this study was to determine the feasibility of using a microendoscopic laminotomy technique to treat spinal stenosis. SUMMARY AND BACKGROUND DATA: Minimally invasive surgery is an important means of reducing tissue trauma and patient morbidity. This may prove to be essential in improving pain and in reducing postoperative stress responses and delayed sequelae that can lead to unfortunate complications after otherwise uneventful procedures. To date, minimally invasive lumbar endoscopic techniques have not been used to decompress the lumbar spinal canal. METHODS: In each of four cadavers, the laminae of L1 through L4 were subjected to one of four procedures consisting of unilateral microendoscopic laminotomy, bilateral microendoscopic laminotomy, unilateral open laminotomy, and bilateral open laminotomy. Every procedure was performed once at all levels. Computed tomography was performed before and after laminotomy to establish the extent of decompression of the spinal canal, and measurements of the midsagittal, interpedicular, and decompression diameters were taken. RESULTS: The four procedures were successfully performed at every level. Satisfactory decompression of the spinal canal was achieved regardless of the approach used. The exiting nerve roots were well visualized when any one of these techniques was used. Complications, including dural tears and facet complex instability, were independent of the procedure performed. CONCLUSION: Microendoscopic laminotomy can be used to decompress the spinal canal as effectively as an open laminotomy and may prove to be beneficial in decreasing the complications and morbidity of standard treatments for lumbar stenosis.

Cadaver↗

PubMed2002

Vertebroplasty for osteoporotic compression fractures: current practice and evolving techniques.

Perutaneous vertebroplasty was developed in France by Deramond et al., who provided initial reports of the procedure in 1987. This minimally invasive procedure uses a large-bore bone-cutting needle to percutaneously access a vertebral body, inject bone cement, and thereby stabilize and reinforce the remaining bone structure. The procedure was used initially to treat aggressive hemangiomas, but it then was extended to the treatment of osteolytic metastases and myeloma and currently osteoporotic compression fractures refractory to medical therapy. In this article, we review the current technique and its indications along with emerging devices and areas of current research.

Aged↗