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Biomedical subjects

Alexander Vaccaro

Publications and source records attributed to Alexander Vaccaro.

7 recordsLinked to original sources
PubMed2006

Wear and corrosion in retrieved thoracolumbar posterior internal fixation.

STUDY DESIGN: Posterior thoracolumbar spine implants retrieved as part of routine clinical practice over a 2-year period were analyzed to identify wear and corrosion. OBJECTIVE: Engineering analyses of retrieved posterior instrumentation for indications of performance and failure and correlation of this information with clinical factors. SUMMARY OF BACKGROUND DATA: Recent studies have reported spinal instrumentation particulate wear debris and have noted the importance of design considerations at implant connector interfaces. METHODS: A total of 57 implants were analyzed from patients (39 female, 18 male) whose average age at implantation was 43.9 years (range, 13.7-77.4 years). Time of implantation ranged from 2 months to 13.5 years. The top 3 implantation diagnoses were radiculopathy (33%), scoliosis (30%), and back pain (25%). Metallurgical analyses were performed to characterize the wear and/or corrosion, and fractures of the implants. RESULTS: Wear was present in 75%, corrosion in 39%, and fractures in 7% of the retrieved implants. Wear and/or corrosion was more prevalent, with respect to the total number of implants retrieved, in implants that had been in service at least 1 year. There was no evidence of corrosion in any of the Ti implants, whereas corrosion was present (with wear) in 58% of the stainless steel (SS) implants. Wear and corrosion were more frequently observed in long rods than in short rods. Implantation times were longer for SS implants than for Ti implants. CONCLUSIONS: Retrieved rods exhibited corrosion, wear, and fracture, with wear and corrosion mainly located at the interfaces with hooks, screws, or cross-connectors. The mechanisms causing this material loss in situ, as well as what local or systemic responses it may stimulate are of clinical significance and should be studied further.

Adolescent↗
PubMed2006

Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group.

STUDY DESIGN: Systematic review. OBJECTIVES: To review the various radiographic parameters currently used to assess traumatic thoracolumbar injuries, emphasizing the validity and technique behind each one, to formulate evidence-based guidelines for a standardized radiographic method of assessment of these fractures. SUMMARY OF BACKGROUND DATA: The treatment of thoracolumbar fractures is guided by various radiographic measurement parameters. Unfortunately, for each group of parameters, there has usually been more than 1 proposed measurement technique, thus creating confusion when gathering data and reporting outcomes. Ultimately, this effect results in clinical decisions being based on nonstandardized, nonvalidated outcome measures. METHODS: Computerized bibliographic databases were searched up to January 2004 using key words and Medical Subject Headings on thoracolumbar spine trauma, radiographic parameters, and methodologic terms. Using strict inclusion criteria, 2 independent reviewers conducted study selection, data abstraction, and methodologic quality assessment. RESULTS: There were 18 original articles that ultimately constituted the basis for the review. Of radiographic measurement parameters, 3 major groups were identified, depicting the properties of the injured spinal column: sagittal alignment, vertebral body compression, and spinal canal dimensions, with 14 radiographic parameters reported to assess these properties. CONCLUSIONS: Based on a systematic review of the literature and expert opinion from an experienced group of spine trauma surgeons, it is recommended that the following radiographic parameters should be used routinely to assess thoracolumbar fractures: the Cobb angle, to assess sagittal alignment; vertebral body translation percentage, to express traumatic anterolisthesis; anterior vertebral body compression percentage, to assess vertebral body compression, the sagittal-to-transverse canal diameter ratio, and canal total cross-sectional area (measured or calculated); and the percent canal occlusion, to assess canal dimensions.

Consensus↗
PubMed2006

The impact of four common lumbar spine diagnoses upon overall health status.

BACKGROUND CONTEXT: The Short Form 36 (SF-36) health survey has been shown to be a valid instrument when used to measure the self-reported physical and mental health of patients. The impact of lumbar spinal disorders can be assessed as the difference between the SF-36 scale scores and age- and gender-specific population norms. PURPOSE: To establish the impact upon the self-reported health status of patients with one of four common lumbar spinal diagnoses. STUDY DESIGN: A cross-sectional, observational assessment of the health status of spine patients. METHODS: Data from patients presenting to the participating centers of the National Spine Network with low back pain or leg pain were collected prospectively using the Health Status Questionnaire 2.0. A database search identified patients with either herniated nucleus pulposus with radicular pain (HNP), lumbar spinal stenosis without deformity (SPS), degenerative spondylolisthesis (DS), and painful disc degeneration/spondylosis (DDD). The mean SF-36 scale scores were generated for each of the diagnostic groups. The impact of these diagnoses on health status was determined as the calculated difference from the age- and gender-specific population norms for each of the eight health scale scores. These scores, usually negative in this population, represent how far below normal these patients are. The analysis was stratified according to the age of the patients (<40 years, 40-60 years, >60 years). Analysis of variance and pair-wise comparison with Bonferroni correction were used to assess the significance of differences across diagnosis and age groups. RESULTS: Data from a total of 4,442 patients were available for this study. All four diagnostic groups had large, negative impact scores for the eight general health scales with the greatest impact upon the three scales that best measure physical health. The greatest impact on these physical health scales (physical functioning, role-physical, and bodily pain) was seen in the HNP diagnostic group. The younger age groups (<40 years and 40-60 years) had the greatest physical impairment when compared with the age- and gender-specific population norms. Analysis of variance showed a significant relationship between diagnosis and SF-36 scores, and between age groups and SF-36 scores. CONCLUSIONS: All four lumbar spine disorders have a significant negative impact on all eight of the SF-36 scales. The greatest negative impact was seen in those scales that measure physical health (role limitations due to physical symptoms [RP], physical functioning [PF], and bodily pain [BP]). The HNP diagnostic group experienced a significantly greater impact upon these three scales. This diagnostic group had the youngest patients, whose baseline physical functional status would be expected to be the most optimal. When we stratified by age in all the diagnostic groups, the greatest negative impact scores for physical health were seen in the <40 years and 40-60 years age groups. These patients were also more likely to perceive their health as poor, experience decreased energy, and have more social impairment when compared with their age/gender norms.

Adult↗
PubMed2006

Recurrent laryngeal nerve palsy after anterior cervical spine surgery: the impact of endotracheal tube cuff deflation, reinflation, and pressure adjustment.

BACKGROUND: Vocal fold immobility (paresis or paralysis) from recurrent laryngeal nerve injury remains an important cause of morbidity after anterior cervical spine surgery. A maneuver involving endotracheal tube (ETT) cuff manipulation has been proposed to reduce its incidence. This study is a randomized, prospective, double-blind investigation to test the hypothesis that ETT cuff manipulation reduces the incidence of postoperative vocal fold immobility after anterior cervical spine surgery. METHODS: One hundred patients scheduled to undergo anterior cervical spine surgery were randomly assigned to one of two groups. After inducing general endotracheal anesthesia, patients in the intervention group had their ETT cuff pressures maintained at 20 mmHg or less. After placement of self-retaining retractors, the ETT cuff was deflated for 5 s and then reinflated. Patients in the control group had no further manipulation of their ETT once the cuff was inflated after intubation. Cuff pressures in both groups were recorded before skin incision (baseline) and after placement of self-retaining retractors (peak). Patients' vocal fold motion was evaluated by indirect laryngoscopy performed preoperatively and postoperatively. The examination was videotaped and reviewed by a blinded otolaryngologist. Postoperative vocal fold motion was graded as normal, paretic, or paralyzed. RESULTS: Complete data were available in 94 patients. The incidence of vocal fold paralysis was 3.2% (95% confidence interval, 0.7-9.4%). Cuff manipulation decreased ETT cuff pressure but did not reduce the incidence of vocal fold immobility (15.4% vs. 14.5%). CONCLUSION: Endotracheal tube cuff deflation/reinflation and pressure adjustment do not reduce the incidence of vocal fold immobility in anterior cervical spine surgery.

Adult↗
PubMed2006

Osteogenic protein-1 : a review of its utility in spinal applications.

The potentially revolutionary effect that bone morphogenic proteins (BMPs) could have on orthopaedic surgery has fueled an exhaustive research effort that continues today. Upwards of 1.5 million bone-grafting operations take place in the US annually, with the anterior and posterior iliac crest being the most common donor site for autologous bone graft. Harvesting autologous bone graft, however, is not benign. It is postulated that a synthetic bone graft containing BMPs would possess the characteristics of autologous bone that allow new bone formation: osteogenesis, osteoinduction, and osteoconduction, without the negative repercussions related to bone harvesting. As a result of the ensuing research following their discovery some 40 years ago by Marshall Urist, the basic science behind BMPs has been largely uncovered. New information on BMPs now comes from clinical trials regarding their utility and efficacy in surgical applications. To date, BMPs have been studied in skeletal bone surgery throughout the body, and have been found to be particularly useful in surgical applications such as spinal arthrodesis. Osteogenic protein-1 (OP-1), or recombinant human BMP-7, is one subtype of BMPs that has shown particular potential in clinical trials. Pre-clinical and clinical studies have, thus far, garnered OP-1 a Humanitarian Device Exemption approval for spinal applications in the US. As clinical trials with larger patient numbers and longer clinical follow-up are completed, the usefulness of OP-1 as a bone graft substitute will be better elucidated.

Animals↗