Introduction

Primary cilia are singular structures containing a microtubule-based axoneme which are believed to not only be mechanosensitive but also to co-ordinate many cell functions via signalling pathways including Hedgehog and Wnt. Primary cilia have previously been described on cells of mouse intervertebral discs (IVDs), but not in bovine or human IVDs. Our aim was to examine primary cilia in these species.

Plots are an elegant and effective way to represent data. At their best they encourage the reader and promote comprehension. A graphical representation can give a far more intuitive feel to the pattern of results in the study than a list of numerical data, or the result of a statistical calculation.

The temptation to exaggerate differences or relationships between variables by using broken axes, overlaid axes, or inconsistent scaling between plots should be avoided.

A plot should be self-explanatory and not complicated. It should make good use of the available space. The axes should be scaled appropriately and labelled with an appropriate dimension.

Plots are recognised statistical methods of presenting data and usually require specialised statistical software to create them. The statistical analysis and methods to generate the plots are as important as the methodology of the study itself. The software, including dates and version numbers, as well as statistical tests should be appropriately referenced.

Following some of the guidance provided in this article will enhance a manuscript.

Cite this article: Bone Joint J 2015;97-B:1593–1603.

Introduction

CT guided percutaneous radiofrequency thermo coagulation is the treatment of choice for osteoid osteomas. Good results with a low complication rate have been shown for spinal lesions. When lesions are within close proximity to neurological structures or if patients have radicular symptoms surgery rather than radiofrequency ablation has been advocated. We present our experience of radiofrequency ablation of spinal osteoid osteomas which are less than 5mm from neurological structures, including those causing radicular symptoms.

Objective

To evaluate the rise in impedance during percutaneous radiofrequency thermo coagulation (PRFTC) of osteoid osteomas as a predictor of local recurrence.

Introduction

Enchondromas located in the phalangeal bones may be more cellular than non-digital locations necessitating clinical and radiological correlation to determine diagnosis. Atypical enchondromas have increased cellularity and atypia relative to simple enchondromas but no evidence of permeation. Chondrosarcomas of the phalanges are thought to have a more indolent course than chondrosarcomas in other locations. The aim of the study was to determine the outcome of atypical enchondromas and grade 1 chondrosarcomas of the phalanges treated surgically.

Periarticular metastasis may be treated with endoprosthetic reconstruction. The extensive surgery required may not, however, be appropriate for all patients. Our aim was to establish if the outcome of locking plate fixation in selected patients with periarticular metastases.

Prospective data collection was performed. Twenty one patients underwent surgery for periarticular metastatic tumours. The median duration of follow-up for surviving patients was one year. There have been no cases of implant failure and no requirement for revision surgery. Pain relief was excellent or good in the majority of patients. Patients who had sustained a fracture prior to fixation had restoration of their WHO performance status. All patients had a dramatic improvement in their MSTS scores. The median pre-operative score was 15% (0%-37%) improving to a median score of 80% (75% -96%) post operatively.

Locking plates provide reliable fixation and excellent functional restoration in selected patients suffering from periarticular metastatic bone disease.

CT guided percutaneous radiofrequency thermocoagulation is the treatment of choice for osteoid osteomas. Good results with a low complication rate have been shown for spinal lesions. When lesions are within close proximity to neurological structures or if patients have radicular symptoms surgery rather than radiofrequency ablation has been advocated. We present our experience of radiofrequency ablation of spinal osteoid osteomas which are less than 5mm from neurological structures, including those causing radicular symptoms.

Data was collected prospectively on all patients with a spinal osteoid osteoma within 5mm of nerve roots or the spinal cord as measured on CT scanning.

There were nine patients, five female and four male with a mean age of 15 years. Four tumours were located in the thoracic spine, three in the lumbar spine and two in the cervical spine. The mean distance to the nearest neurological structure was 3mm. Radicular symptoms were present in two patients. The mean number of probe positions used was two. Lesions were heated to 90 degrees for 5 minutes for each probe position. There were two cases of recurrence, both treated successfully with one further procedure each. There were no cases of neurological injury. The two patients with radicular symptoms had full resolution of their symptoms. At a mean follow up of 2 years following treatment all patients are asymptomatic.

Radiofrequency ablation can be safely performed to treat osteoid osteomas located within 5mm of neurological structures and has a low rate of recurrence.

Purpose

To report a retrospective study of 103 cases of primary spinal infection, the largest ever such series from the UK, analysing presenting symptoms, investigations, bacteriology and the results of treatment.

Introduction: The Optiplug^® bio-absorbable cement restrictor, marketed by Biomet inc., is manufactured from ‘PolyActive’ – a polymer of poly(ethylene glycol) and butylene terephthalate. Biodegradation is thought to be by a combination of hydrolysis and oxidation.

The potential benefit – eliminating the need for restrictor removal at future revision surgery – led to Optiplug becoming our cement restrictor of choice over the last 5 years.

Anecdotally we have seen marked osteolysis around the distal cement mantle in a number of follow up radiographs in these patients. To date we have not seen an associated peri-prosthetic fracture.

We undertook a retrospective, radiographic study to determine incidence, severity and progression of this osteolysis over the first 5 years of follow up.

Method: 100 patients for whom 5 year follow up had been undertaken were identified from the departmental database. Patients with loose prostheses and or infection were excluded as were those who had undergone revision surgery.

Radiographs from the immediate post operative period, twelve months and five years follow up visits were identified and reviewed.

Osteolysis was quantified by calculating the ratio of maximum medullary diameter to the overall cortical diameter of the bone. Comparison was made over time and, where radiographs allowed, to the immediately adjacent femur.

Results: 87% of radiographs showed greater than 10% thinning of the cortex at 1 year cf. immediate post op. 5 cases showed greater than 33% thinning. These changes do not appear to progress or regress significantly between 1 and 5 years.

Discussion: While marked osteolytic changes appear to be uncommon, some degree of cortical thinning was almost universal in this series. The zone immediately distal to the cement mantle is commonly involved in peri-prosthetic fractures. Any weakening in this area is undesirable.

We present a series of 14 patients presenting to the senior surgeon’s practice who sustained thoracolumbar burst fractures, with no neurological loss. The patients were treated with early mobilisation and extension bracing. We assessed their pain and disability, using VAS and ODI, and their fracture morphology. There was no statistical correlation between any measured parameter of fracture morphology and pain or disability. There was correlation between age at injury, time elapsed from injury and psychosocial aspects of the injury and the subsequent disability.

The measured disability was low and compared favourably with the results of studies of patients treated surgically.

We continue to treat all our neurologically intact burst fractures by early mobilisation and bracing, and take no account of fracture morphology in our decision making.

Introduction: Posterior wall acetabular fractures are potentially difficult fractures to treat due to difficulties associated with the types of approach, reduction and fixation required. Spring plates are a method of maintaining such fractures reduced.

Aims: To assess the clinical and radiological outcome with spring plate fixation of posterior wall fractures.

Materials and Methods: From July 1993 to August 2004, 91 patients with 92 displaced posterior wall fractures underwent posterior wall fixation with one or more spring plates.

All patients were assessed postoperatively with a CT scan and annually for up to 5 years for a clinical and radiological assessment. Clinically patients were graded according to the Epstein modification of Merle D’Aubigne/ Postel Hip Score. The radiographs were graded using the Roentographic Grade criteria used by Matta.

Results: Patients were reviewed at a mean 44 month follow up.

At the time of operation 40% of fractures were reduced anatomically. There were 12 post operative complications.

Clinically excellent or good results were seen in 70% and radiologically in 68%. There were 11 revisions for osteonecrosis, infection and osteoarthritis.

There was a high correlation between the accuracy of the reduction and the subsequent prognosis.

Conclusion: Posterior wall fractures can be treated successfully by the use of spring plates. Clinical results correspond closely with radiological appearance. The accuracy of reduction correlates highly with the subsequent prognosis and we recommend routine postoperative CT scanning to identify misplaced metalwork and the accuracy of reduction to help predict prognosis.

Introduction: Rotation is becoming an increasingly important consideration in the management of scoliosis yet it is difficult to measure reliably. The Perdriolle technique is a widely used and validated technique for estimating the rotation of the apical vertebra. The landmarks required to measure vertebral rotation using this technique are frequently obscured following instrumentation and the application of bone graft. We propose that the Perdriolle technique cannot be applied reliably in the presence of pedicle screw constructs.

Method: This was a manual radiographic measurement analysis comparing intraobserver and interobserver reliability of the Perdriolle “Torsiometre” and the Cobb angle measurement in scoliosis prior to and after pedicle screw instrumentation.

Results: Mean difference and 95% limits of agreement between pre-operative intra-observer readings was 2.5° (−15° and 20°). This suggests on average there was little systematic disagreement between the two readings (2.5° on average). There were large discrepancies between individual pairs of readings.

29.6% of post-operative films (17%–39%) were judged to have sufficient landmarks visible to enable measurement of vertebral rotation compared to 10% of pre-operative films.

Marked increase in systematic bias between consultants with post-operative radiographs to pre-operative films was observed.

Conclusion: We question the validity in measuring the rotation of the curve using the Perdriolle technique on post-operative films following pedicle screw instrumentation. The predominant factors for the obscuration of landmarks include the presence of bone graft, pedicle screws and rods.

We studied the long term outcome, using the Oswestry Disability Index (ODI), on patients who were managed at our institution between February, 1997, and August, 2004, with a diagnosis of a primary spinal infection, excluding TB or post-operative infection. Patients were identified from databases held within the Departments of Radiology, Orthopaedic Surgery, Neurosurgery and Microbiology. This identified 98 adult patients who fulfilled our inclusion criteria, of who ODIs were calculated on 66, with a mean follow-up of 5 years. There were initially 53 male and 45 female patients with a mean age of 60 years (range 21 0 86) at presentation and symptoms had been present on average for 72 days prior to admission. Back pain was the predominant symptom in 59 and neuropathy in 43. Our figures would suggest a mush higher incidence of primary spinal infection than previously quoted. 75% had significant co-morbidities and 85% of patients under 40 years of age were IV drug users. The causative organisms and their effect were noted. Admission WCC (mean 11.5 ± 8.6) and CRP (mean 128 ± 48) were obtained in the majority of patients (97/98 & 94/98). For those patients who were still available to f/u, the mean ODI was 32 ± 25.

Purpose: To evaluate the long term clinical outcomes as well as radiological changes in distal unfused mobile segments and to evaluate factors that may predispose to distal disc degeneration and/or poor outcome.

Method: 151 mobile segments in 85 patients (65 female), mean age 43.2 (range 21–68), were studied. Curve type, number of fused levels and pelvic incidence were recorded. Clinical outcome was measured using the Whitecloud function scale and disc degeneration using the UCLA disc degeneration score. Spinal balance, local segmental angulations and lumbar lordosis were measured pre- and post-operatively as well as at the most recent follow up – mean 9.3 years (range 7–19).

Results: 62% of patients had a good or excellent outcome. 11 had a poor outcome of which 10 underwent extension of fusion – 5 for pain alone, 3 pain with stenosis and 2 pseudarthroses. Pre-operative disc degeneration was often asymmetric and was slightly greater in older patients. Overall, there was a significant deterioration in disc degeneration (p< 0.0001) that did not correlate with clinical outcome. Disc degeneration correlated with the recent sagittal balance (Anova F=14.285, p< 0.001) and the most recent lordosis (Anova F=4.057, p=0.048). The post-operative sagittal balance and local L5-S1 sagittal angulation correlated to L4 and L5 degeneration respectively. There was no correlation between degeneration and age, pre-operative degenerative score, pelvic incidence, sacral slope, number of fused levels or distal level of fusion.

Conclusion: Disc degeneration does occur below an arthrodesis for scoliosis in adults which does not correlate with clinical outcome. The correlation of loss of sagittal balance with disc degeneration may be as a result of degeneration causing the loss of balance or vice versa i.e. sagittal imbalance causing degeneration. Immediate post-operative imbalance correlates with degeneration of the L4/5 disc, which may imply the latter.

Purpose: We describe a technique using orthoganol imaging on a radiolucent table that allows reliable, safe and reproducible insertion of thoracic pedicle screws.

Method: The popularity of pedicle screws for spinal fixation in deformity surgery has increased. Studies have shown lumbar pedicle screws to be safe and effective. The biomechanical superiority of pedicle screws has also been demonstrated. Nonetheless, reluctance to apply the technique to thoracic vertebra remains, most likely because of perceived technical difficulties and a reported high complication rate.

We describe a technique using orthoganol imaging on a radiolucent table, used in a series of patients in whom we have inserted a total of over 2000 screws.

Results: We have inserted over 2000 thoracic pedicle screws without neurological injury. In addition, this technique has allowed us to use pedicle screw to the exclusion of other, less mechanically favourable, methods of fixation to the spine; over the same time period we used only three sublaminar hooks.

Furthermore, the lateral to medial or ‘toeing in’ of screw placement gives greater pull out strength to each screw by increasing the ‘volume’ of bone that has to be overcome before failure by pull out occurs. In addition this trangulation technique allows insertion of :screws of greater diameter than the pedicle and decreases the chance of broaching medially.

Conclusion: Using the technique described, we achieve accurate screw placement ‘first time, every time’, giving us a biomechanically superior construct, allowing more powerful derotation of the spine and thus greater correction of deformity. We recommend its use for all thoracic pedicle screws.