Biomedical subjects

Brian J C Freeman

Publications and source records attributed to Brian J C Freeman.

13 recordsLinked to original sources

PubMed2007

Biofilm formation by Propionibacterium acnes on biomaterials in vitro and in vivo: impact on diagnosis and treatment.

Propionibacterium acnes is found increasingly as a cause of delayed infection, usually involving implanted biomaterials. Despite susceptibility to common antibiotics, such infections are very difficult to treat and usually require surgical removal of the device. Three clinical isolates of P. acnes were assessed for ability to adhere to titanium, surgical steel and silicone, with and without a plasma conditioning film. After adherence, the biomaterials were then incubated for a further 6 days and examined for biofilm development. All three isolates adhered to all three biomaterials similarly. Importantly, we were able to demonstrate biofilm formation, including production of exopolymer similar in appearance to the polysaccharide intercellular adhesin of Staphylococcus epidermidis. A case summary also demonstrated failure to eradicate P. acnes infection in a hydrocephalus shunt after prolonged treatment. The removed shunt showed obvious biofilm formation, initially obscured by exopolymer when viewed by environmental scanning electron microscopy. Biofilm development by P. acnes explains the difficulties encountered in clinical management of such infections.

Bacterial Adhesion↗

PubMed2006

IDET: a critical appraisal of the evidence.

Smith and Nephew (Endoscopy division, Andover, MA, USA) have estimated that 60,000 Intra-Discal Electrothermal Therapy (IDET) procedures have been performed world wide up to June 2005. Despite the large number of procedures performed, a critical appraisal of the evidence of efficacy of IDET has not appeared in the literature. This paper reviews the current evidence of clinical efficacy for IDET obtained via a systematic review of the literature. Studies were included if they used at least one of four specified primary outcome measures; pain intensity as assessed by a visual analogue score (VAS), global measurement of overall improvement, back specific functional status such as Oswestry disability Index (ODI) and return to work. Levels of evidence were assigned according to the hierarchy described by the Oxford Centre for Evidence-Based Medicine (www.cebm.net). Papers addressing possible mechanisms of action of IDET were not considered as the focus of the literature review was clinical effectiveness. Eleven prospective cohort studies (level II evidence) were reported on a total of 256 patients with a mean follow-up of 17.1 months (range 12-28 months). The mean improvement in the VAS for back pain was 3.4 points (range 1.4-6.5) and the mean improvement in ODI was 5.2 points (range 4.0-6.4). A total of 379 patients were reported in five retrospective studies (level III evidence). Between 13 and 23% of patients subsequently underwent surgery for low back pain within the study period. Two randomised controlled trials of IDET have been reported in the literature. The first randomised 64 patients (37 to IDET, 27 to Sham). The advantage for IDET patients amounted to 1.3 points on the VAS and seven points on the ODI. The second study randomised 57 subjects (38 to IDET, 19 to Sham) and showed no benefit from IDET over placebo. The evidence for efficacy of IDET remains weak and has not passed the standard of scientific proof.

Back Pain↗

PubMed2006

Total disc replacement in the lumbar spine: a systematic review of the literature.

The current evidence for total disc replacement was assessed by performing a systematic review of the published literature. This search identified two randomised controlled trials (RCTs), two previous systematic reviews, seven prospective cohort studies, eleven retrospective cohort studies and eight case series. The RCTs involved the use of the Charité artificial disc and the Pro-Disc II total disc replacement. All papers analysed were classified according to their level of evidence as defined by the Centre for Evidence Based Medicine, Oxford, UK (www.cebm). For degenerative disc disease at L4/5 or L5/S1, both the clinical outcome and the incidence of major neurological complications following insertion of the Charité artificial disc were found to be equivalent to those observed following a single level anterior lumbar interbody fusion 2 years following surgery. However, only 57% of patients undergoing total disc replacement and 46% of patients undergoing arthrodesis met the four criteria listed for success. The range of flexion/extension was restored and maintained with the Charité artificial disc. The role for two or three level disc replacement in the treatment of degenerative disc disease remains unproven. To date, no study has shown total disc replacement to be superior to spinal fusion in terms of clinical outcome. The long-term benefits of total disc replacement in preventing adjacent level disc degeneration have yet to be realised. Complications of total disc replacement may not be known for many years. There are numerous types of disc prostheses and designs under study or in development. Well designed prospective RCTs are needed before approval and widespread application of this technology.

Clinical Trials as Topic↗

PubMed2006

Blood audit evidenced-based cross-match requesting for lumbar spine surgery.

STUDY DESIGN: Complete audit cycle. OBJECTIVE: Radical overhaul of the blood ordering practices made by the spinal surgery department, in order to maximize the efficient use of blood products. SUMMARY OF BACKGROUND DATA: Spinal surgeons request blood-based on historical practice and not evidence. Blood is a scarce resource. Provision relies on voluntary donations from the general population. However, the donor population has been reduced because of the risks of variant Creutzfeldt-Jakob disease. Hence, the responsibility rests with clinicians to optimize their management of blood. METHODS: The spinal surgery department database was accessed to identify all patients who underwent elective lumbar spine operations (excluding deformity) during 2002 to 2003. These records were then cross-referenced with the blood transfusion department database. From the results the cross-match to transfusion (C:T) ratios and transfusion indexes (TI) were calculated for the procedures. A new tariff was agreed between the surgeons, anesthetists, and transfusion department. This was then audited prospectively. RESULTS: There were 664 cross-match requests made during 2002 to 2003, and only 40 U was transfused. This gave a C:T ratio of 16.6:1. The prospective audit resulted in only 58 U being cross-matched and 5 were transfused. This reduced the C:T ratio to 11.5:1. CONCLUSION: Implementing evidence based cross-match protocols can make significant savings in time, manpower, and money.

Blood Grouping and Crossmatching↗

PubMed2006

Is there a role for selective anterior instrumentation in neuromuscular scoliosis?

Our objective was to report on the clinical and radiological outcome from a cohort of patients with neuromuscular scoliosis who underwent selective anterior single rod instrumentation for correction of thoraco-lumbar and lumbar scoliosis. Traditionally combined anterior release with long posterior instrumentation has been advocated for the treatment of neuromuscular scoliosis. Neuromuscular curves tend to be long and may have significant pelvic obliquity. However, certain neuromuscular curves with minimal pelvic obliquity may lend themselves to selective anterior correction thereby saving motion segments and allow continued ambulation for those patients. Nine patients with neuromuscular scoliosis underwent selective anterior instrumentation between 1994 and 2000. The mean follow up was 2 years and 9 months (range 24-55 months). The clinical outcome (including parent and caregiver satisfaction), radiological outcome (Cobb angle, apical vertebral translation, pelvic obliquity, truncal shift, thoracic kyphosis, lumbar lordosis, sagittal vertical axis) and complications are reported. Subjective outcome was excellent in six patients and good in three. All nine patients retained their ability to walk. There were no neurological or vascular complications. Supplementary posterior surgery was required in two patients. The mean pre-operative Cobb angle of 52 degrees (range 44-60) improved to 20 degrees (range 10-28) at 3 months, achieving Cobb angle correction of 61% and was 19 degrees (range 7-28) at final follow-up. The mean pre-operative compensatory curve of 31 degrees (range 20-42) spontaneously corrected to 18 degrees (range 14-24) at 3 months and was maintained at 18 degrees (range 10-26) at final follow up. The mean pre-operative pelvic obliquity of 7 degrees (range 0-14) corrected to 4 degrees (range 0-8) at 3 months and was 3 degrees (range 0-8) at final follow up. Selective anterior instrumentation and fusion in carefully selected patients with neuromuscular scoliosis (short flexible curves, minimal pelvic obliquity, pre-operative walkers, slow or non-progressive pathology) appears to have satisfactory clinical and radiological outcome at least in the short-term.

Adolescent↗

PubMed2005

A randomized, double-blind, controlled trial: intradiscal electrothermal therapy versus placebo for the treatment of chronic discogenic low back pain.

STUDY DESIGN: A prospective, randomized, double-blind, placebo-controlled trial of intradiscal electrothermal therapy (IDET) for the treatment of chronic discogenic low back pain (CDLBP). OBJECTIVES: To test the safety and efficacy of IDET compared with a sham treatment (placebo). SUMMARY OF BACKGROUND DATA: In North America alone, more than 40,000 intradiscal catheters have been used to treat CDLBP. The evidence for efficacy of IDET is weak coming from retrospective and prospective cohort studies providing only Class II and Class III evidence. There is one study published with Class I evidence. This demonstrates statistically significant improvements following IDET; however, the clinical significance of these improvements is questionable. METHODS: Patients with CDLBP who failed to improve following conservative therapy were considered for this study. Inclusion criteria included the presence of one- or two-level symptomatic disc degeneration with posterior or posterolateral anular tears as determined by provocative computed tomography (CT) discography. Patients were excluded if there was greater than 50% loss of disc height or previous spinal surgery. Fifty-seven patients were randomized with a 2:1 ratio: 38 to IDET and 19 to sham procedure (placebo). In all cases, the IDET catheter was positioned to cover at least 75% of the annular tear as defined by the CT discography. An independent technician connected the catheter to the generator and then either delivered electrothermal energy (active group) or did not (sham group). Surgeon, patient, and independent outcome assessor were all blinded to the treatment. All patients followed a standard postprocedural rehabilitation program. Independent statistical analysis was performed. OUTCOME MEASURES: Low Back Outcome Score (LBOS), Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36), Zung Depression Index (ZDI), and Modified Somatic Perceptions Questionnaire (MSPQ) were measured at baseline and 6 months. Successful outcome was defined as: no neurologic deficit, improvement in LBOS of greater then 7 points, and improvement in SF-36 subsets (physical function and bodily pain) of greater than 1 standard deviation. RESULTS: Baseline demographic data, initial LBOS, ODI, SF-36, ZDI, and MSPQ were similar for both groups. No neurologic deficits occurred. No subject in either arm showed improvement of greater than 7 points in LBOS or greater than 1 standard deviation in the specified domains of the SF-36. Mean ODI was 41.42 at baseline and 39.77 at 6 months for the IDET group, compared with 40.74 at baseline and 41.58 at 6 months for the placebo group. There was no significant change in ZDI or MSPQ scores for either group. CONCLUSIONS: The IDET procedure appeared safe with no permanent complications. No subject in either arm met criteria for successful outcome. Further detailed analyses showed no significant change in outcome measures in either group at 6 months. This study demonstrates no significant benefit from IDET over placebo.

Adult↗

PubMed2005

A prospective, randomised controlled trial of femoral ring allograft versus a titanium cage in circumferential lumbar spinal fusion with minimum 2-year clinical results.

The literature reports on the safety and efficacy of titanium cages (TCs) with additional posterior fixation for anterior lumbar interbody fusion. However, these papers are limited to prospective cohort studies. The introduction of TCs for spinal fusion has resulted in increased costs, without evidence of superiority over the established practice. There are currently no prospective controlled trials comparing TCs to femoral ring allografts (FRAs) for circumferential fusion in the literature. In this prospective, randomised controlled trial, our objective was to compare the clinical outcome following the use of FRA (current practice) to the use of TC in circumferential lumbar spinal fusion. Full ethical committee approval and institutional research and development departmental approval were obtained. Power calculations estimated a total of 80 patients (40 in each arm) would be required to detect clinically relevant differences in functional outcome. Eighty-three patients were recruited for the study fulfilling strict entry requirements (>6 months chronic discogenic low back pain, failure of conservative treatment, one- or two-level discographically proven discogenic low back pain). The patients completed the Oswestry Disability Index (ODI), Visual Analogue Score (VAS) for back and leg pain and the Short-Form 36 (SF-36) preoperatively and also postoperatively at 6, 12 and 24 months, respectively. The results were available for all the 83 patients with a mean follow-up of 28 months (range 24-75 months). Five patients were excluded on the basis of technical infringements (unable to insert TC in four patients and FRA in one patient due to the narrowing of the disc space). From the remaining 78 patients randomised, 37 received the FRA and 41 received the TC. Posterior stabilisation was achieved with translaminar or pedicle screws. Baseline demographic data (age, sex, smoking history, number of operated levels and preoperative outcome measures) showed no statistical difference between groups (p<0.05) other than for the vitality domain of the SF-36. For patients who received the FRA, mean VAS (back pain) improved by 2.0 points (p<0.01), mean ODI improved by 15 points (p=<0.01) and mean SF-36 scores improved by >11 points in all domains (p<0.03) except that of general health and emotional role. For patients who received the TC, mean VAS improved by 1.1 points (p=0.004), mean ODI improved by 6 points (p=0.01) and SF-36 improved significantly in only two of the eight domains (bodily pain and physical function). Revision procedures and complications were similar in both groups. In conclusion, this prospective, randomised controlled clinical trial shows the use of FRA in circumferential lumbar fusion to be associated with superior clinical outcomes when compared to those observed following the use of TCs. The use of TCs for circumferential lumbar spinal fusion is not justified on the basis of inferior clinical outcome and the tenfold increase in cost.

Adult↗

PubMed2005

The Modic classification: inter- and intraobserver error in clinical practice.

STUDY DESIGN: A reliability study of the Modic classification. OBJECTIVE: To determine the reliability and reproducibility of the Modic classification for lumbar vertebral marrow changes. SUMMARY OF BACKGROUND DATA: In 1988, Modic et al described two degenerative stages of vertebral marrow and endplate morphology. These were type 1 (inflammatory phase) and type 2 (a fatty phase). Later in 1988, he added a third variety: type 3 where there was marked sclerosis adjacent to the endplates. No formal reliability or reproducibility studies had been performed on this Modic classification. METHODS: This study involved five independent observers of differing spinal experience using the Modic classification to grade 50 sagittal T1- and T2-weighted magnetic resonance imaging scans. The observers repeated the assessment at 3 weeks. Intra- and interobserver reliabilities were assessed using kappa statistics. RESULTS: There were 7 type 1, 40 type 2, 1 type 3, and 2 normal levels. The individual intraobserver agreement was substantial or excellent with kappa values ranging from 0.71 to 1. The overall interobserver agreement was excellent with a kappa value of 0.85. There was complete agreement in 78% of the levels, a difference of one type in 14% and a difference of two or more in 8% of levels. The level of experience of the observer did not correlate with a better score. CONCLUSIONS: We have shown that the classification is both reliable and reproducible. It is simple and easy to apply for observers of varying clinical experience. We therefore recommend its use in clinical research and practice.

Adult↗

PubMed2005

Bilateral occipital condyle fractures leading to retropharyngeal haematoma and acute respiratory distress.

Injuries to the occipito-cervical junction are rare and not easily diagnosed on conventional radiographs. The authors report such a case where the diagnosis was delayed. The patient developed a significant retrophyarngeal haematoma resulting in acute respiratory distress and required emergency endotracheal intubation. The patient remained intubated for five days and received a tapered dose of intravenous dexamethazone to reduce swelling in the proximity of the airway. At six weeks the patient had developed a left hypoglossal nerve palsy that persisted at 12 months. Occipital condyle fractures and the difficulties of diagnosis are discussed. The importance of measuring pre-vertebral soft tissue swelling on lateral radiographs is emphasized. Computed tomography of the C0-C2 region should be performed to identify base of skull and upper cervical fractures.

Accidents↗

PubMed2003

Does intradiscal electrothermal therapy denervate and repair experimentally induced posterolateral annular tears in an animal model?

STUDY DESIGN: The effects of intradiscal electrothermal therapy (IDET) on intervertebral discs in sheep were studied experimentally. OBJECTIVES: Posterolateral annular lesions were experimentally induced and allowed to mature for 12 weeks in the intervertebral discs of sheep. IDET was performed in an attempt to denervate and repair the annular lesion. The histologic and immunohistochemical effects of IDET were studied. SUMMARY OF BACKGROUND DATA: IDET continues to be used as a minimally invasive treatment for chronic discogenic low back pain, with success rates reported in up to 70% of cases. The mechanism of action by which IDET exerts its effect is poorly understood. Proposed mechanisms include the contraction of collagen and the coagulation of annular nociceptors. An ovine model was used firstly to induce a posterolateral annular lesion, secondly to assess the innervation of such a lesion, and thirdly to assess the effect of IDET on this innervation. MATERIALS AND METHODS: Posterolateral annular incisions were made in 40 lumbar discs of 20 sheep. Twelve weeks were allowed for each annular lesion to mature. IDET was then performed in the disc with the posterolateral annular tear and in another control level. IDET was performed using a modified intradiscal catheter (Spine-CATH; Oratec Interventions, Menlo Park, CA). Temperatures were recorded in the nucleus (TN) and the posterior annulus (TPA). The spines were harvested at predetermined intervals up to 18 months. Histologic sections of the discs were graded for disc morphology to assess degeneration and immunohistochemical staining to assess potential denervation. RESULTS: Vascular granulation tissue consistent with a healing response was observed in the posterior annular tear of all incised discs from 12 weeks. Protein gene product 9.5 (PGP 9.5) positive nerve fibers were clearly identified in the adjacent periannular tissue and the outer few lamellae of the posterior annulus. During the IDET procedure, the mean maximum TPA was 63.6C and the mean maximum TN was 67.C.At sacrifice, the number of nerve fibers identified in the posterior annular tear was the same for those specimens that had undergone IDET and those that had not. From 6 weeks after IDET, there was evidence of thermal necrosisin the inner annulus and adjacent nucleus but sparing the periphery of the disc. CONCLUSIONS: Vascular granulation tissue and posterior annular neo-innervation was observed in the experimentally induced posterolateral annular lesion. IDET delivered at 90C in the sheep consistently heated the posterior annulus and the nucleus to a temperature normally associated with coagulation of nociceptors and collagen contraction. IDET did not denervate the posterior annular lesion. Thermal necrosis was observed within the inner annulus and adjacent nucleus from 6 weeks after IDET. The reported benefits from IDET appear to be related to factors other than denervation and repair.

Animals↗

PubMed2003

A prospective randomized comparison of coralline hydroxyapatite with autograft in cervical interbody fusion.

STUDY DESIGN: A prospective randomized trial with independent clinical and radiographic outcome review of patients receiving either hydroxyapatite or tricortical iliac crest graft for cervical interbody fusion was conducted. OBJECTIVE: To determine whether coralline-derived hydroxyapatite is a suitable bone graft substitute in cervical interbody fusion. SUMMARY OF BACKGROUND DATA: Tricortical iliac crest bone is the "gold standard" graft material for cervical interbody fusion. Various bone substitutes have been used for this procedure to avoid potential donor site morbidity. ProOsteon 200 is a coralline-derived hydroxyapatite product, the use of which remains unclear for cervical interbody fusion. METHODS: In this study, 29 patients undergoing anterior cervical fusion and plating were randomized to receive either ProOsteon 200 or iliac crest grafts. The SF-36 and Oswestry Disability Index were used to measure clinical outcome. Postoperative radiographs were analyzed for graft fragmentation, loss of height, angular alignment, and hardware failure to assess structural integrity of the graft material. Plain radiographs and computed tomography scans were used to evaluate fusion. RESULTS: Both the ProOsteon 200 and iliac crest groups demonstrated significant improvement in clinical outcome scores. There was no significant difference in clinical outcome or fusion rates between the two groups. Graft fragmentation occurred in 89% of the hydroxyapatite grafts and 11% of the autografts (P = 0.001). Significant graft settling occurred in 50% of the hydroxyapatite grafts, as compared with 11% of the autografts (P = 0. 009). One patient in the ProOsteon 200 group required revision surgery for graft failure. CONCLUSIONS: ProOsteon 200 does not possess adequate structural integrity to resist axial loading and maintain disc height or segmental lordosis during cervical interbody fusion.

Bone Transplantation↗

PubMed2002

The Adams classification for cadaveric discograms: inter- and intra-observer error in the clinical setting.

The Adams classification for discogram morphology is based on a cadaveric study. It provides the basis for several subsequent classifications proposed in the literature. However, little or no attention has been paid to its reproducibility in the clinical setting. The authors assessed the reliability of this classification using three independent observers of differing experience. One hundred and thirty-three discograms belonging to 71 patients with chronic low back pain were reviewed in a randomised and blinded manner. The morphological appearance at each discogram level was assessed and assigned a type according to the Adams classification. The exercise was repeated 3 weeks later. Respective inter- and intra-observer agreements were calculated in the standard fashion using the kappa statistic. Both inter- and intra-observer agreements were excellent (kappa= 0.77-0.85). The Adams grading system for discogram morphology is consistently reproducible amongst observers with differing levels of experience. It can be safely recommended in the clinical setting as a reliable classification.

Adult↗

PubMedDate not supplied

Do anterior interbody cages have a potential value in comparison to autogenous rib graft in the surgical management of Scheuermann's kyphosis?

BACKGROUND CONTEXT: Previous studies have analyzed the outcome following posterior correction and combined anterior-posterior correction for Scheuermann's kyphosis. Traditionally interbody fusion has been obtained using morselized rib graft. Recently the use of titanium anterior cages has been suggested for interbody use. There are no long-term studies comparing these two techniques. PURPOSE: To investigate the potential value of titanium anterior interbody cages compared with morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction, and fusion for Scheuermann's kyphosis. STUDY DESIGN: Nonrandomized comparison of two surgical techniques in matched subjects. PATIENT SAMPLE: Fifteen patients with identical preoperative radiographic and physical variables (age, gender, height, weight, body mass index) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction, and fusion. Group A (n=8) had morselized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. OUTCOME MEASURES: Preoperative and postoperative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson's angle, Voutsinas index, sagittal vertical axis (SVA), sacral inclination (SI), and lumbar lordosis (LL). Interbody fusion was assessed at final follow-up. Each patient was reviewed at 3, 6, 12, 24, 48, and 60 months after surgery with standing radiographs. METHODS: Both surgical groups were compared in terms of radiological parameters and complications. Wilcoxon-matched pairs test and Mann-Whitney test were used. RESULTS: The average follow-up for Group A was 70 months and for Group B 66 months. For the whole group, the preoperative median Cobb angle for thoracic kyphosis was 86 degrees , the median Ferguson angle was 50 degrees , Voutsinas index was 28.7, SVA -3.5 centimeters, lumbar lordosis was 66 degrees , and the median sacral inclination angle was 40 degrees . The median postoperative Cobb angle was 42 degrees , Ferguson angle 28.4 degrees , Voutsinas index 13, SVA -4.0 centimeters, and the median sacral inclination angle was 34 degrees . There were significant differences between preoperative and postoperative measurements for all variables (p<.01), indicating that good correction was achieved. At 4-year follow-up, fusion criteria were satisfied in 12 of 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference obtained in the final Cobb angle, Ferguson angle, and Voutsinas index when Group A (rib graft) was compared with Group B (titanium cage) Both Group A and B patients retained the postoperative correction achieved with respect to all the radiographic parameters studied. CONCLUSION: We were unable to demonstrate any significant advantage for the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann's kyphosis. Given the not inconsiderable cost and the need for posterior chevron osteotomies when interbody cages are used, we have now reverted to our previous practice of using morselized rib graft at each intervertebral level.

Adult↗