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Biomedical subjects

P Renton

Publications and source records attributed to P Renton.

At least 19 recordsLinked to original sources
PubMed2001

The use of allograft (and avoidance of autograft) in anterior lumbar interbody fusion: a critical analysis.

The aim of this report is to analyze the validity of allograft in anterior lumbar interbody fusion. Forty-three patients underwent anterior lumbar interbody fusion using allograft in the period between 1995 and 1998. All suffered from crippling chronic low back pain with or without sciatica. Discogenic disease was verified in 40 cases by discography. All patients were investigated preoperatively with magnetic resonance imaging (MRI). The surgical technique is described. Follow-up radiographs were performed postoperatively, then at 1.5, 3, 6 and 12 months, as required. Radiological fusion was confirmed in all single-level fusions (100%, n=24). In two-level fusions the rate was 93% (n=28/30). However, radiological union could only be confirmed in 11 of the 12 levels in the three-level fusions. Allograft offers a better alternative to autograft for anterior lumbar interbody fusion. Donor site morbidity is avoided, hospital stay is shorter and fusion rates are satisfactory.

Bone Transplantation↗
PubMed1999

Chondromyxoid fibroma of the sacrum.

A 30-year-old man with a 7-month history of mild sacral pain and intermittant left sciatica was found to have an expansile lesion in the sacrum on a plain radiograph. Biopsy confirmed a chondromyxoid fibroma which was removed surgically. A 1-year follow-up showed no recurrence. The case is the fifth to be reported. Plain film and MRI appearances, histology and treatment are described. The previously reported cases are reviewed and the current literature is discussed.

Adult↗
PubMed1998

The value of lumbar spine magnetic resonance imaging in the demonstration of anular tears.

STUDY DESIGN: Retrospective review of magnetic resonance imaging and discography in patients investigated for low back pain before spinal fusion. OBJECTIVE: To determine the sensitivity of magnetic resonance imaging in the detection of painful anular tears manifested by the high-intensity zone. SUMMARY OF BACKGROUND DATA: Two studies have produced results showing that magnetic resonance imaging has a high specificity for the detection of painful anular tears manifested by a high-intensity zone. However, in a recent study, results showed no significant correlation between the high-intensity zone and pain reproduction. The sensitivity of magnetic resonance imaging in identifying anular tears in a symptomatic population has not been determined. METHODS: Anular tears were identified in magnetic resonance images by the presence of a high-intensity zone in the posterior anulus. The results were compared with the demonstration of painful anular tears on discogram, which has been considered the gold standard. RESULTS: The study group comprised 58 patients (31 men, 27 women; mean age 42, range 21-63 years). One hundred and fifty-two discs were injected and examined by discography, and 108 were considered degenerate. Of these, 86 had anular tears (54 posterior, 6 anterior, 26 both). Seventy anular tears were associated with concordant pain provocation. Twenty-seven high-intensity zones were identified in magnetic resonance imaging, of which 24 were associated with pain reproduction by discography. The sensitivity, specificity, positive predictive value, and negative predictive value of magnetic resonance imaging in the diagnosis of concordantly painful posterior anular tears are therefore 26.7%, 95.2%, 88.9%, and 47%, respectively. CONCLUSION: These results confirm that the high-intensity zone is a marker of a painful posterior anular tear. However, the usefulness of this sign is limited by low sensitivity.

Adult↗
PubMed1998

Technetium-99m human immunoglobulin imaging in patients with subacromial impingement or adhesive capsulitis.

Although recognised as useful in detecting soft-tissue inflammation and infection, technetium-99m human immunoglobulin (Tc-99m HIG) has not been widely studied in evaluating regional inflammatory musculoskeletal conditions. Tc-99m HIG scintigraphy was undertaken for consecutive patients referred to a rheumatology clinic with unilateral shoulder pain, diagnosed with either subacromial impingement (n = 12) or adhesive capsulitis (n = 4) from clinical examination, radiographic, and in some cases arthrographic findings. In all patients there were no differences in Tc-99m HIG images between symptomatic and asymptomatic shoulders. The findings are discussed, with reference to patterns of tissue inflammation which have been associated with each of the two conditions and in the context of patients referred to hospital relatively late after onset of symptoms (4-6 months).

Bursitis↗
PubMed1998

Effects on the vertebral end-plate of uncomplicated lumbar discography: an MRI study.

The study aimed to identify and characterise changes occurring in the vertebral end-plate on MRI following uncomplicated lumbar discography. MRI was performed immediately before and within 2 h after uncomplicated lumbar discography in 20 consecutive patients undergoing the study as a precursor to possible spinal fusion. Of these, seven patients underwent a further MRI study at a mean of 72 days after discography (range 19-183 days). The MRI scans were assessed for the presence of any changes in the end-plates prior to and following discography. End-plate changes were identified in eight patients (40%) prior to discography. No new changes in end-plate signal intensity (SI) were identified in either the immediate or delayed MRI studies. The study suggests that any changes occurring in the vertebral end-plate following discography should be considered due to infectious discitis. There is no support for the concept of chemical discitis, chemical irritation of bone or microfracture of subchondral trabeculae as a cause of pain at discography.

Adult↗
PubMed1998

Simultaneous combined anterior and posterior lumbar fusion with femoral cortical allograft.

The radiographic fusion rates, graft behaviour and clinical outcome of 41 patient with simultaneous combined anterior lumbar interbody fusion and posterior arthrodesis with translaminar screws were reviewed independently. In all patients a femoral cortical allograft (FCA) ring filled with autologous iliac crest cancellous bone was used anteriorly to replace the disc and achieve interbody fusion. The follow-up averaged 30.6 months, with a minimum follow-up of 24 months. All patients had disabling low-back pain with different degrees of radiating leg pain and either discogenic pain (n = 24) or a postdiscectomy syndrome (n = 15) respectively postfusion syndrome (n = 2). The overall fusion rate was 95.2% (59 of 62 segments). Time to radiographic fusion averaged 8.7 months (range 2-34 months), and in 66.1% radiographic fusion occurred without significant subsidence. In 18.6% fusion with subsidence resulted from resorption of the FCA and in 15.3% the FCA had protruded into the vertebral body. The posterior intervertebral disc height (PIVDH) increased postoperatively by 2 mm on average. However, loss of PIVDH was the rule, and occurred within the first 12 postoperative months, resulting in a negligible final gain in height of 0.3 mm on average. The segmental lordosis was increased by 3 degrees; however, loss of lordosis during the first 6 postoperative months led to a final gain in lordosis of 1.3 degrees on average. Graft incorporation occurred in 16 of 62 segments (25.8%) and was observed at an average of 21.9 months postoperatively. Subjectively, 82.4% of the patients were satisfied or highly satisfied with the clinical result of the fusion operation. In conclusion, the described technique has proven to be highly effective in achieving a high fusion rate with a good patient outcome.

Adult↗
PubMed1998

An analysis of radiating pain at lumbar discography.

This study aimed to identify the morphological abnormalities of the intervertebral disc, as demonstrated by lumbar discography, that are associated with pain radiation to the hip, groin, buttock or lower limb. We carried out a retrospective review of 99 consecutive lumbar discogram reports. The association of disc degeneration, annular tears (partial or full thickness) and the level of disc injected was determined with respect to the presence and pattern of radiating pain. A total of 260 discs were injected, of which 179 were considered abnormal. Posterior annular tears were demonstrated in 84 discs, anterior annular tears in 15 discs and 45 discs had both anterior and posterior tears. A significant association was identified between isolated posterior tears and the production of concordant radiating pain (P = 0.0041). No difference was identified between partial thickness posterior tears and full thickness posterior tears associated with leak of contrast medium, with regard to radiating pain. Similarly, there was no significant association between disc level injected and the pattern of pain radiation. The results indicate that pain experienced in the buttock, hip, groin or lower limb can arise from the posterior annulus of the intervertebral disc without direct involvement of the nerve root.

Adult↗
PubMed1998

Vertebral end-plate (Modic) changes on lumbar spine MRI: correlation with pain reproduction at lumbar discography.

The vertebral end-plate has been identified as a possible source of discogenic low back pain. MRI demonstrates end-plate (Modic) changes in 20-50% of patients with low back pain. The aim of this study was to investigate the association between Modic changes on MRI and discogenic back pain on lumbar discography. The MRI studies and discograms of 58 patients with a clinical diagnosis of discogenic back pain were reviewed and the presence of a Modic change was correlated with pain reproduction at 152 disc levels. Twenty-three discs with adjacent Modic changes were injected, 21 of which were associated with pain reproduction. However, pain was also reproduced at 69 levels where no Modic change was seen. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for a Modic change as a marker of a painful disc were 23.3%, 96.8%, 91.3% and 46.5% respectively. Modic changes, therefore, appear to be a relatively specific but insensitive sign of a painful lumbar disc in patients with discogenic low back pain.

Adult↗
PubMed1998

Radiology of metabolic bone disease: osteoporosis.

This is the first in a pair of articles looking at the radiographic appearance of metabolic bone diseases which lead to a loss of bone density known as osteopenia. This article looks at different forms of osteoporosis, a term used to imply a specific pathology and which does not cover all forms of osteopenia.

Adolescent↗
PubMed1998

Radiology of rickets, osteomalacia and hyperparathyroidism.

In osteoporosis, the amount of mineralized bone is diminished, but the remaining bone is of normal quality. In rickets and osteomalacia the trabeculae are irregularly mineralized, a feature reflected in the X-ray image. In hyperparathyroidism there is generalized and focal bone resorption leading to demineralization and poor definition of bone on the X-ray.

Bone and Bones↗
PubMed1994

Anterior lumbar fusion using a hybrid interbody graft. A preliminary radiographic report.

This is a radiographic report of 40 patients (20 men, 20 women) who underwent anterior lumbar interbody fusions (73 levels) utilizing a "hybrid" interbody graft composed of femoral cortical allograft (FCA) bone and iliac crest cancellous autograft bone. The average age at surgery was 38 years (range 17-64 years), and follow-up averaged 1.4 years (range 1.0-2.4 years). Nineteen of the patients had undergone previous lumbar surgery. Thirty-two patients (63 levels) underwent anterior fusion combined with some type of posterior fixation, and eight patients (10 levels) had no posterior fixation. Types of posterior fixation included: for 20 patients (36 levels) Steffee variable screw placement fixation, for 10 patients (23 levels) translaminar facet screws (TFS), for 1 patient (3 levels) Knodt rods and for 1 patient (1 level) facet screws. Based on the persistence of lucent lines at the graft-host interface, three patients (one level each) were felt to have non-unions at their latest follow-ups at 1.4, 1.5 and 2.0 years, respectively. Two of these patients had no posterior fixation, and the other had TFS fixation. The overall fusion rate was 96% (70 of 73 levels). The fusion rate for all levels treated with posterior fixation was 98% compared with 75% for those without fixation. Intervertebral disc heights (IVDH) were measured on all films and corrected for magnification with computer assistance. On average, the IVDH was increased postoperatively but returned to preoperative values at follow-up. IVDH loss was independent of the type of instrumentation used. No complications arose from the use of the hybrid graft.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Comparison of arthrotomographic and magnetic resonance images of 50 temporomandibular joints with operative findings.

Arthrotomography and magnetic resonance imaging (MRI) were carried out on 50 temporomandibular joints (TMJs) in 48 patients who were being considered for surgery for clinically diagnosed internal derangement. The patients presented over a 4-year period with pain and dysfunction which had failed to respond to conservative management. Open surgery was carried out on all TMJs and operative findings compared with the results of imaging. The clinical diagnosis of internal derangement was confirmed in every case by imaging and at surgery. Arthrotomography over-diagnosed non-reducibility of an anteriorly displaced meniscus and perforation. MRI over-diagnosed non-reducibility to a lesser extent and under-diagnosed perforation. MRI demonstrated neither bony changes nor adhesions. Dynamic arthrotomography produced the best images of meniscal derangement in function and the pre-arthrogram tomograms were the best indicator of osseous abnormality. Arthrotomography was the preferred imaging technique.

Adolescent↗
PubMed1993

Metaphyseal abnormalities in fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is a rare, congenital disorder characterized by diffuse ossification of extraskeletal connective tissue. The classical features and progression of the disease are described and three cases are presented which fall into the general pattern of FOP clinically and radiologically. A constant feature seen was a slight metaphyseal flaring with spiking at the edges of the metaphyses, compatible with minor alteration in bone morphology during growth. These changes cannot be seen after epiphyseal fusion. The major abnormalities persist into adult life.

Bone and Bones↗
PubMed1984

Comparative study of iohexol and meglumine iothalamate in double-contrast knee arthrography.

A comparison has been made between meglumine iothalamate and a low-osmolar contrast medium, iohexol, in arthrography of the knee. A controlled study evaluated the immediate and delayed patient response as well as the quality of the examination, which was assessed by two radiologists without knowledge of which contrast medium had been employed. The results show that iohexol is a good contrast medium for knee arthrography but offers no advantages to offset the increased cost compared with contrast media in current use.

Adolescent↗
PubMed1981

The value or arthrography in the management of internal derangements of the knee: the first 1000 are the worst.

The acceptance of arthrography of the knee as an accurate diagnostic procedure by both radiologists and orthopaedic surgeons in the United Kingdom has been slow compared to many other parts of the world. The value of arthrography in the diagnosis of meniscal lesions is discussed with reference to the first 1000 documented cases in the authors' series. It is considered that the results obtained from such early experience is more relevant to those about to start as an arthrographic service. Problems in clinical, arthrographic and arthroscopic diagnosis are discussed. Arthrography constitutes an accurate method of diagnosing such lesions and should be employed whenever clinical doubt about the diagnosis of an internal derangement of the knee is encountered. In a selected group of 137 patients, in whom both arthrography and arthroscopy was performed, the two investigations showed a comparable accuracy of 89.8 and 88.3% respectively.

Adolescent↗