Biomedical subjects

Paul Klimo

Publications and source records attributed to Paul Klimo.

At least 19 recordsLinked to original sources

PubMed2006

Pediatric arteriovenous malformations: a 15-year experience with an emphasis on residual and recurrent lesions.

OBJECT: Pediatric arteriovenous malformations (AVMs) are generally treated with microsurgical resection to achieve complete obliteration. We review our experience treating AVMs in children, particularly those with residual or recurrent lesions. METHODS: The records of 39 patients with AVMs (25 girls: 14 boys; average age 10.3 years) treated during a 15-year period were reviewed (mean follow-up 30 months). Three primary outcomes were analyzed: AVM obliteration by last follow-up, residual on postoperative angiograms and recurrence after angiographic "cure." RESULTS: Most children (57%) presented with spontaneous intracerebral hemorrhage, the average nidus size was 3.4 cm, and the modal Spetzler-Martin grade was 2. AVMs were classified as compact (82%) or diffuse (18%). Most patients (90%) underwent surgery as their primary treatment. The immediate obliteration rate was 76% and the overall, long-term obliteration rate was 89%. Nine (23%) patients had residual nidus after initial treatment; five of these underwent further treatment that obliterated their lesion. Five (13%) patients developed recurrence within 6 years, including one patient with two recurrences. Three were successfully treated with a repeat resection. Patients with diffuse-type AVMs were at greater risk of having a persistent lesion (40%), residual lesion (44%), or recurrence (80%) at last follow-up. CONCLUSION: Most pediatric AVMs can be successfully treated with microsurgical resection. Endovascular treatment is reserved primarily as a preoperative adjunct and stereotactic radiosurgery for inoperable AVMs. Patients may develop recurrences years after their original treatment. Patients with diffuse-type AVMs were less likely to be cured and more likely to have a residual or a recurrence.

Adolescent↗

PubMed2006

Computed tomography grading schemes used to predict cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a historical review.

The elucidation of predictive factors of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is a major area of both clinical and basic science research. It is becoming clear that many factors contribute to this phenomenon. The most consistent predictor of vasospasm has been the amount of SAH seen on the postictal computed tomography scan. Over the last 30 years, it has become clear that the greater the amount of blood within the basal cisterns, the greater the risk of vasospasm. To evaluate this risk, various grading schemes have been proposed, from simple to elaborate, the most widely known being the Fisher scale. Most recently, volumetric quantification and clearance models have provided the most detailed analysis. Intraventricular hemorrhage, although not supported as strongly as cisternal SAH, has also been shown to be a risk factor for vasospasm.

History, 20th Century↗

PubMed2006

Surgical strategies for recurrent craniofacial meningiomas.

OBJECTIVE: Recurrent cranial base meningiomas are among the most difficult tumors to treat surgically. Although they are histologically benign, these tumors often invade through the cranial base into the infratemporal and pterygopalatine fossae. We reviewed our experience with these tumors to describe the natural history of these lesions as well as provide a possible treatment paradigm. METHODS: Between 2000 and 2004, seven patients with meningiomas recurring through the cranial base into facial structures were treated at the University of Utah. Five patients were treated with transcranial approaches only, and two were treated with a combination of transcranial and transfacial approaches. RESULTS: The average age of our patients (6 women, 1 man) was 55 years. The original site of tumor was the sphenoid wing in four patients, the middle fossa in two patients, and the left frontal region in one patient. The average interval between the most recent tumor resection and recurrence into the face was 9.9 years. The mean number of resections a patient underwent before invasion into the face was two. All but one patient had adjunctive therapy (including either radiation or chemotherapy) before recurrence into the face. CONCLUSION: Meningiomas that recur into facial structures present a unique treatment challenge. These lesions have a high rate of recurrence once they have invaded through the cranial base. Although combined approaches may be necessary to achieve a gross total resection, these lesions can often be reached using standard transcranial techniques.

Adult↗

PubMed2006

Anterior cervical fixation: analysis of load-sharing and stability with use of static and dynamic plates.

BACKGROUND: Anterior plates provide stability following decompression and fusion of the cervical spine. Various plate designs have emerged, and they include static plates with fixed-angle screws, rotationally dynamic plates that allow the screws to toggle in the plate, and translationally dynamic plates that allow the screws to both toggle and translate vertically. The goal of this study was to document the effects of plate design following a single-level corpectomy and placement of a full-length strut graft and the effects following 10% subsidence of the graft. METHODS: A total of twenty-one cadaveric cervical spines (C2-T1) were randomized into three treatment groups and were tested for initial range of motion. A C5 corpectomy was performed, reconstruction was done with a full-length interbody spacer containing a load-cell, and an anterior cervical plate was applied. Load-sharing data were recorded with incremental axial loads. The range of motion was measured with +/- 2.5 Nm of torque in flexion-extension, lateral bending, and axial rotation. Then, the total length of the interbody spacer was reduced by 10% to simulate subsidence, and load-sharing and the range of motion were retested. RESULTS: With the full-length interbody spacer, there were no significant differences in the abilities of the constructs to share load or limit motion. Following shortening of the interbody spacer, the static plate construct lost nearly 70% of its load-sharing capability, while neither of the dynamic plate constructs lost load-sharing capabilities. Also, the static plate construct allowed significantly more motion in flexion-extension following simulated subsidence than did either of the dynamic plate constructs (p < 0.05). CONCLUSIONS: Although all of the tested anterior cervical plating systems provide similar load-sharing and stiffness following initial placement of the interbody spacer, the static plate system lost its ability to share load and limit motion following simulated subsidence of the interbody spacer. Both dynamic plate systems maintained load-sharing and stiffness despite simulated subsidence. CLINICAL RELEVANCE: This study provides an improved understanding of the immediate performance of anterior cervical fusion surgery with plate fixation.

Aged↗

PubMed2006

Multilevel cervical disconnection syndrome: initial description, embryogenesis, and management. Report of two cases.

Two cases of a previously undescribed cervical spinal anomaly distinct from cervical spondylolysis are presented. The authors report the first detailed description of a congenital vertebral anomaly characterized by multilevel cervical spondylolysis, sagittal deformity, and spinal cord compression. The sine qua non of the condition is a lack of communication between the anterior and posterior columns of the cervical spinal canal, which may occur over several vertebral levels. A kyphotic deformity of the anterior column occurs, whereas the posterior column may have relatively normal alignment. The underlying biomechanical stresses caused by the anterior-posterior column disconnection result in spinal instability and progressive kyphotic deformity, often to a profound degree. Two children, 2 and 3 years of age, presented with congenital multilevel disconnection and myelopathy. In the first stage of treatment, each underwent an anterior decompression, reduction, and reconstruction of the involved segments. This was followed by posterior stabilization and fusion as a separate procedure. In both patients, the myelopathy improved and a solid, circumferential fusion was achieved. The authors' success in treating these patients indicates that management of these conditions can be based on the principles of deformity correction, spinal cord decompression, and combined anterior-posterior arthrodesis.

Biomechanical Phenomena↗

PubMed2006

Vertebra plana due to an aneurysmal bone cyst of the lumbar spine. Case report and review of the literature.

Aneurysmal bone cysts (ABCs) are benign, highly vascular osseous lesions characterized by cystic, blood-filled spaces surrounded by thin perimeters of expanded bone. Children and young adults are most often affected by spinal ABCs; more than 75% of patients are younger than 20 years old at presentation. Although ABCs have been documented in all areas of the axial and appendicular skeleton, ABCs of the spine present unique challenges due to the risk of vertebral destabilization, pathological fracture and vertebral body (VB) collapse, and neurological compromise. The authors describe the case of an 8-year-old child who presented with low-back pain and was subsequently found to have a lumbar ABC causing vertebra plana of the L-3 VB. They also review the literature on ABCs of the spine. This case highlights the importance of considering an ABC in the differential diagnosis when vertebra plana is seen in pediatric patients.

Bone Cysts, Aneurysmal↗

PubMed2005

A meta-analysis of surgery versus conventional radiotherapy for the treatment of metastatic spinal epidural disease.

Radiotherapy has been the primary therapy for managing metastatic spinal disease; however, surgery that decompresses the spinal cord circumferentially, followed by reconstruction and immediate stabilization, has also proven effective. We provide a quantitative comparison between the "new" surgery and radiotherapy, based on articles that report on ambulatory status before and after treatment, age, sex, primary neoplasm pathology, and spinal disease distribution. Ambulation was categorized as "success" or "rescue" (proportion of patients ambulatory after treatment and proportion regaining ambulatory function, respectively). Secondary outcomes were also analyzed. We calculated cumulative success and rescue rates for our ambulatory measurements and quantified heterogeneity using a mixed-effects model. We investigated the source of the heterogeneity in both a univariate and multivariate manner with a meta-regression model. Our analysis included data from 24 surgical articles (999 patients) and 4 radiation articles (543 patients), mostly uncontrolled cohort studies (Class III). Surgical patients were 1.3 times more likely to be ambulatory after treatment and twice as likely to regain ambulatory function. Overall ambulatory success rates for surgery and radiation were 85% and 64%, respectively. Primary pathology was the principal factor determining survival. We present the first known formal meta-analysis using data from nonrandomized clinical studies. Although we attempted to control for imbalances between the surgical and radiation groups, significant heterogeneity undoubtedly still exists. Nonetheless, we believe the differences in the outcomes indicate a true difference resulting from treatment. We conclude that surgery should usually be the primary treatment with radiation given as adjuvant therapy. Neurologic status, overall health, extent of disease (spinal and extraspinal), and primary pathology all impact proper treatment selection.

Aged↗

PubMed2005

Potentially useful outcome measures for clinical research in pediatric neurosurgery.

The choice of outcome (or outcomes) and their measurement are critical for a sound clinical trial. Surgeons have traditionally measured simple outcomes such as death, duration of survival, or tumor recurrence but have recently developed more sophisticated measures of the effect of an intervention. Many outcome measures require a lengthy maturation process, which includes a determination of the instrument's validity, reliability, and sensitivity; thus, using established instruments rather than creating new ones is recommended. The authors illustrate several guidelines for the determination of appropriate outcome measures by using examples from their experience and describe several outcome measures that can be used in pediatric neurosurgery. These include general outcome measures such as the Pediatric Evaluation of Disability Inventory and the Functional Independence Measure for Children, which measure physical function and independence in chronically ill and disabled children as well as disease-specific measures for hydrocephalus (Hydrocephalus Outcome Questionnaire), cerebral palsy (gross motor function and performance measures), head injury (Pediatric Cerebral Performance Category and Children's Coma Scale), and oncology (Pediatric Cancer Quality-of-Life Inventory).

Activities of Daily Living↗

PubMed2005

Metastatic spinal cord compression.

Approximately 70% of cancer patients have metastatic disease at death. The spine is involved in up to 40% of those patients. Spinal cord compression may develop in 5% to 10% of cancer patients and up to 40% of patients with preexisting nonspinal bone metastasis (>25,000 cases/y). Given the increasing survival times of patients with cancer, greater numbers of patients are likely to develop this complication. The role of surgery in the management of metastatic spinal cord compression is expanding. The management of metastatic spine disease can consist of a combination of surgery, radiation treatment, and chemotherapy. Treatment modalities are not mutually exclusive and must be individualized for patients evaluated in a multidisciplinary setting.

Combined Modality Therapy↗

PubMed2004

Posterior surgical approaches and outcomes in metastatic spine-disease.

Spinal cord compression represents a major cause of morbidity and suffering in cancer patients. Surgery should be considered a form of primary therapy in many of these patients. The goals of surgery and the approach used are functions of a number of variables, including the surgeon's preference, the location of disease within the spine (cervical, thoracic, or lumbar),the extent of disease within each vertebra, the number of levels affected, and the patient's medical health and overall prognosis. Currently,the goals of any major debulking surgery are to decompress the spinal cord, prevent local recurrence, reconstruct the spine, and provide immediate stabilization with the use of fixation devices. Posterior approaches, starting with the decompressive laminectomy, have traditionally been the most common surgical procedures for metastatic spine disease. The laminectomy should only be used for disease isolated to the dorsal spine without evidence of concomitant instability. A laminectomy combined with instrumentation has been shown to provide superior results but should be reserved for those patients who cannot tolerate or would not benefit from more aggressive surgery. Various posterolateral approaches have been devised to access more ventrally placed lesions. These include the transpedicular approach, the costotransversectomy, and the lateral extracavitary/parascapular approach. Each of these allows adequate spinal cord decompression anteriorly and posteriorly and the ability to reconstruct and stabilize with acceptable peri-operative risk. It must be remembered that surgery for this disease is almost always palliative.Thus, surgery should be a means to maximize the patient's quality of life while minimizing the risk of suffering surgical complications.

Decompression, Surgical↗

PubMed2004

Minimally invasive treatments for metastatic tumors of the spine.

Minimally invasive approaches are finding their way into all aspects of metastatic spinal disease from diagnosis to treatment of patients who are diagnosed early in their course as well as patients with multifocal metastases. For patients who are found to have asymptomatic spinal metastases, diagnosis is important to guide management and treatment so as to prevent future morbidity. These patients also now have the option of less invasive techniques for resection,reconstruction, and stabilization, including endoscopy and less invasive surgical approaches. Patients who are treated later in their course, with multifocal metastatic disease also have more options for palliation of pain and for stability,including vertebroplasty/kyphoplasty and radio-frequency tumor ablation as well as some of the percutaneous methods of stabilization described previously. As techniques evolve and im-prove, patients will continue to have more access to less invasive options for treatment of spinal metastases.

Electrocoagulation↗

PubMed2004

Clinical trials and evidence-based medicine for metastatic spine disease.

Treatment of metastatic epidural spinal disease has undergone significant changes over the last 20 years. No longer is indiscriminate decompressive laminectomy offered as the only surgical treatment. It carries all the risks associated with an invasive procedure and offers the patient little benefit unless it is used to remove disease isolated to the posterior elements. The existing literature suggests that surgery that frees the spinal cord at the site of compression in addition to reconstructing and stabilizing the spinal column is more effective at preserving and regaining neural function, notably ambulatory function and sphincter function, than conventional radiotherapy. It is also highly effective in relieving pain. The preliminary results ofa recent RCT provide the first class I evidence to support a reversal in the current philosophy of primary treatment for many patients with meta-static disease. Conventional radiotherapy has a clearly defined role as adjuvant therapy and as primary therapy in those who are unable to tolerate or benefit significantly from surgery. The role of nonconventional radiation therapy, such as IMRT and SRS, remains to be elucidated.

Clinical Trials as Topic↗

PubMed2004

Surgical management of spinal metastases.

Metastatic spread to the spinal column is a growing problem in patients with cancer. It can cause a number of sequelae including pain, instability, and neurologic deficit. If left untreated, progressive myelopathy results in the loss of motor, sensory, and autonomic functions. Except in rare circumstances, treatment is palliative. Traditionally, conventional fractionated external beam radiotherapy has been the treatment of choice. "Surgery" for metastatic spinal disease was, and generally continues to be, equated with laminectomy by many physicians. However, there has been a remarkable evolution in surgical techniques over the last 20 years. Today, the goal of surgery is to achieve circumferential decompression of the neural elements while reconstructing and immediately stabilizing the spinal column. This has been made possible by the use of different surgical approaches and the exploitation of a burgeoning array of internal fixation devices. More recently, minimally invasive surgical techniques, such as endoscopy, kyphoplasty/vertebroplasty, and stereotactic radiosurgery, have been added to the surgeon's armamentarium. As the number of treatment options for metastatic spinal disease grows, it has become clear that effective implementation of treatment can only be achieved by a multidisciplinary approach. This will provide the surest means of maximizing the quality of the remainder of the patient's life.

Humans↗

PubMed2004

Marked reduction of cerebral vasospasm with lumbar drainage of cerebrospinal fluid after subarachnoid hemorrhage.

OBJECT: Cerebral vasospasm after subarachnoid hemorrhage (SAH) continues to be a major source of morbidity in patients despite significant clinical and basic science research. Efforts to prevent vasospasm by removing spasmogens from the subarachnoid space have produced mixed results. The authors hypothesize that lumbar cisternal drainage can remove blood from the basal subarachnoid spaces more effectively than an external ventricular drain (EVD). This non-randomized, controlled-cohort study was undertaken to evaluate the effectiveness of a lumbar drain in patients with SAH compared with those in whom an EVD or no form of cerebrospinal fluid (CSF) drainage was used to prevent the development of clinical vasospasm and its sequelae. METHODS: The authors collected data on 266 patients with nontraumatic SAH who were admitted to the University of Utah Health Sciences Center between January 1994 and January 2003. Of these, 167 met the study entry criteria. The treatment group consisted of 81 patients in whom a lumbar drain had been placed for CSF shunting, whereas the control group was composed of 86 patients who received no form of CSF drainage or who were treated solely with an EVD. Primary outcome measures were as follows: 1) clinically evident vasospasm; 2) the need for endovascular intervention; 3) vasospasm-induced infarction; 4) disposition at time of discharge; and 5) Glasgow Outcome Scale (GOS) score at 1 to 3 months postdischarge. Secondary outcomes included length of stay and the need for CSF shunting. The presence of a lumbar drain conferred a statistically significant protective and beneficial effect across all outcome measures, reducing the incidence of clinical vasospasm from 51 to 17%, the need for angioplasty from 45 to 17%, and the occurrence of vasospastic infarction from 27 to 7% (all p < or = 0.001-0.008). Patients in the treatment group were more likely to be discharged home (54% compared with 25%, p = 0.002) and to have a GOS score of 5 at follow up (71% compared with 35%, p < 0.001). The mean number of days spent in the intensive care unit and in the hospital overall was also fewer in the treatment group. A similar degree of benefit was found in patients with different Fisher grades and regardless of whether an EVD was needed on presentation, both by subgroup analysis and multivariate logistic regression modeling. There was no statistical difference between the groups in terms of patients requiring a shunt. Complications with lumbar drains were rare and yielded no permanent sequelae. CONCLUSIONS: Shunting of CSF through a lumbar drain after an SAH markedly reduces the risk of clinically evident vasospasm and its sequelae, shortens hospital stay, and improves outcome. Its beneficial effects are probably mediated through the removal of spasmogens that exist in the CSF. The results of this study warrant a randomized clinical trial, which is currently under way.

Adult↗

PubMed2004

Complications of intracranial pressure monitoring in children with head trauma.

OBJECT: Intracranial pressure (ICP) monitoring has become routine in the management of patients with traumatic brain injury (TBI). Many surgeons prefer to use external ventricular drains (EVDs) over fiberoptic monitors to measure ICP because of the added benefit of cerebrospinal fluid drainage. The purpose of this study was to examine a consecutive series of children with TBI and compare the incidence of complications after placement of an EVD, a fiberoptic intraparencyhmal monitor, or both. METHODS: A retrospective chart review was conducted to identify children with TBI who met the criteria for insertion of an ICP monitor. All patients underwent head CT scanning on admission and after placement of an ICP monitor. During a 5-year period 80 children met the criteria for inclusion in the study. Eighteen children (22.5%) underwent EVD placement only, 18 (22.5%) underwent placement of a fiberoptic device only, and 44 (55%) received both. A total of 62 fiberoptic devices (48%) were inserted, and 68 EVDs (52%) were placed. Overall, there was a fourfold increased risk of complications in children who received an EVD compared with those in whom a fiberoptic monitor was placed (p = 0.004). Hemorrhagic complications were detected in 12 (17.6%) of 62 patients who received an EVD compared with four (6.5%) of 62 patients who received a fiberoptic monitor (p = 0.025). Six (8.8%) of 68 EVDs were malpositioned and required replacement; in three (50%) of these cases a hemorrhagic complication occurred. Only one infection was noted in a patient with an EVD (1.5%). CONCLUSIONS: In this retrospective cohort of pediatric patients with TBI, complication rates were significantly higher in those receiving EVDs than in those in whom fiberoptic monitors were placed. Although the majority of these complications did not entail clinical sequelae, surgeons should be aware of the different complication rates when choosing the most appropriate device for each patient.

Adolescent↗

PubMed2004

Assessing the validity of the endoscopic shunt insertion trial: did surgical experience affect the results?

OBJECT: Most surgical procedures are associated with a learning curve in which the success rate is lower early in the experience before mistakes have been identified and modifications made to the procedure. Negative results obtained early in a trial's learning curve may be a matter of timing rather than a reflection of the procedure's effectiveness. The recently published results of the Endoscopic Shunt Insertion Trial (ESIT) represent the notion that endoscopically placed shunts were no more likely to survive than conventionally placed shunts. This negative result may be due to inexperience in performing endoscopic surgeries. METHODS: . Surgical experience was assessed in two ways. Shunt survival rates were compared between cases treated endoscopically in the 1st and last years of the ESIT. The effect of center volume was evaluated using a Cox proportional hazard model in which the following variables were analyzed: age at registration, the diagnosis of myelomeningocele, head size, method of shunt placement (endoscopic compared with conventional), and center volume. There was no difference in survival (endurance) of the shunt between patients enrolled in the 1st and last years (log rank = 0.08, p = 0.77). Likewise, no variable in the Cox multivariate model, including center volume, was a significant factor in predicting shunt survival. CONCLUSIONS: The primary result of the ESIT was found to be internally valid. The fact that endoscopic shunt placement did not benefit patients evaluated in the study was not due to early timing of the trial. Any learning curve among the participating surgeons did not adversely affect the results.

Cerebrospinal Fluid Shunts↗

PubMed2004

Use of trastuzumab beyond disease progression: observations from a retrospective review of case histories.

HER2 overexpression is associated with poor breast cancer prognosis and is the target for the humanized monoclonal antibody trastuzumab. This novel agent, when administered until disease progression in combination with chemotherapy, extends the survival of women with HER2-positive metastatic breast cancer (MBC). However, the optimal duration of trastuzumab therapy remains to be confirmed. We conducted a retrospective case review study of women with HER2-positive MBC who continued to receive trastuzumab beyond disease progression. Objectives were to assess whether treatment beyond disease progression shows any evidence of efficacy and to evaluate the feasibility of this approach. One hundred five patients (median age, 47 years; range, 24-77 years) were identified in 13 centers. Women had received </=6 chemotherapy regimens (median, 1) before trastuzumab therapy. Median survival from first trastuzumab dose was 29 months. The overall response rate to trastuzumab alone or with a taxane as the first regimen was 39%; a further 30% of patients had stable disease as the best response. These rates were 36% and 38% after a second regimen of trastuzumab alone or with paclitaxel or vinorelbine was administered. Some patients responded to both the first and second regimens; others responded to the second regimen after the first had failed. Twenty-two patients experienced cardiac events, of whom 18 received >/=1 more trastuzumab regimen. Trastuzumab treatment beyond progression appears to be of value, producing responses and clinical benefit, and is well tolerated without significant cardiac toxicity. The feasibility of this approach warrants examination in prospective trials.

Adult↗

PubMed2003

Treatment of metastatic spinal epidural disease: a review of the literature.

OBJECT: Spinal cord compression is one of the most dreaded complications of metastatic cancer. It can lead to a number of sequelae, including pain, spinal instability, neurological deficits, and a reduction in the patient's quality of life. Except in selected circumstances, treatment is palliative. Treatment options include surgery, radiation, and chemotherapy. The goal of this study was to summarize the existing data on the outcomes of various treatment methods for metastatic spinal epidural disease and to make appropriate recommendations for their use. METHODS: The authors used a search strategy that included an electronic database search, a manual search of journals, analysis of bibliographies in relevant review papers, and consultation with the senior author. There is good evidence, including Class I data, that steroid drugs constitute a beneficial adjunctive therapy in patients with myelopathy from epidural compression. Historically, conventional radiation therapy has been viewed as the first-line treatment because it has been shown to be as effective as a decompressive laminectomy, with a lower incidence of complications (Class II data). Nevertheless, in the last 20 years there has been remarkable progress in surgical techniques and technology. Currently, the goals of surgery are to achieve a circumferential decompression of the spinal cord, and to reconstruct and immediately stabilize the spinal column. Results in a large body of literature support the belief that surgery is better at retaining or regaining neurological function than radiation and that surgery is highly effective in relieving pain. Most of the data on the treatment of metastatic spinal disease are Class II or III, but the preliminary results of a well-designed, randomized controlled trial in which surgery is compared with standard radiation therapy represents the first Class I data. CONCLUSIONS: As the number of treatment options for metastatic spinal disease has grown, it has become clear that effective implementation of these treatments can only be achieved by a multidisciplinary approach.

Adrenal Cortex Hormones↗