Background

Venous thromboembolism deterrent (TED) stockings are recommended for all orthopaedic patients. Clinical evidence supporting their use is limited and the risk of DVT increases four-fold if pressure gradients are reversed. This study aims to investigate the efficacy of TED stockings and their application using pressure gradients as the outcome measure.

Reviewing our experience of scoliosis in children with a Cavopulmonary Shunt or Fontan circulation and the cardiovascular challenges that this presents.

A notes and x ray review was performed. Special attention was paid to the changes in cardiovascular status whilst prone. The review was from first presentation to latest follow up.

There were 6 patients who underwent 7 major procedures between 2001 and 2009. All had cardiac procedures in early life. Both definitive fusion and growing instrumentation was used. All procedures were successful. Growing instrumentation allowed earlier primary surgery before completion of the Fontan circulation. All have been subsequently lengthened in a lateral position. The mean follow up is 56 months. There was one death 40 months following last surgery, cause unrelated to spinal surgery.

In the older patients with a completed Fontan significant blood loss was seen, due to the raised venous pressure required to run the Fontan, and occult hypotension seen as a climbing difference between Pulmonary Artery Wedge Pressure and Central Venous Pressure were common when prone.

We recommend early intervention, using instrumentation without fusion to correct the deformity over time and allow intervention prior to completing the Fontan circulation. As haemodynamic instability increases with increasing time in the prone position, surgery should be expedited rapidly.

Purpose: To determine whether combined modality Positron Emission Tomography and Computed Tomography (PET-CT) imaging can pre-operatively identify de-differentiated areas within well-differentiated liposarcomas/ atypical lipomatous neoplasms. Well-differentiated lipo-sarcomas show a reasonably homogeneous lesion with fat signal characteristics on MRI and are managed with surgical excision or regular observation. They can recur locally, but never metastasize. Up to 5% of well-differentiated liposarcomas will contain a de-differentiated component that is not apparent on MRI. When present, this de-differentiated component carries a much worse prognosis and requires more aggressive local management. Currently this is only identified after surgical resection. Pre-operative identification of a de-differentiated component within the lesion by PET-CT would allow for better treatment planning. However, PET-CT is an expensive investigation and has not been reported in this application before, although it has been used for imaging of soft tissue tumours.

Method: We have prospectively enrolled 40 subjects into this study. Eligible subjects presented with a > 8cm and deep well-differentiated liposarcoma in the extremities or retroperitoneum, which was confirmed by MRI. Subjects underwent a pre-operative PET-CT scan to look for areas of de-differentiation within the lesion. The PET-CT results were compared to the final pathological analysis of the surgical specimen. When necessary for diagnostic purposes, cytogenetic analysis was also completed.

Results: Thirty-one of the 40 subjects enrolled have had PET-CT scan and surgery. Seven subjects are waiting for PET-CT and surgery by December 2009. Two subjects were withdrawn from the study: one because the PET-CT scan could not be scheduled prior to surgery, and one because the subject ultimately declined surgery. Of the 31 lesions excised, 2 contained de-differentiated areas within the lesion. The PET-CT detected a small area of low to moderate FDG uptake (thigh lesion, max Standard Uptake Value (SUV) 3.6) for one of these patients; however no uptake on PET-CT was seen for the other (retroperitoneal lesion, max SUV 1.7).

Conclusion: PET-CT does not appear to reliably detect de-differentiated areas within well-differentiated lipo-sarcomas. Our data does not support the use of PET-CT for this purpose as it may be misleading and wasteful of resources.

We performed a prospective, randomised, blinded clinical trial comparing metal versus polyethylene bearing surfaces in patients receiving a THA.

Forty-one patients were randomised to receive a metal (twenty-three) or a polyethylene (eighteen) insert with identical femoral and acetabular components. The metal bearing was a 28mm low carbon on high carbon couple. Patients were evaluated pre-operatively, at three, six, twelve months and annually thereafter, including an evaluation of erythrocyte and urine cobalt, chromium, and titanium, outcome measures (WOMAC, SF-12, Harris Hip Score) and radiographs.

No patients were lost to follow-up. At an average 7.2 (range 6.1 – 7.8) years follow-up there were no differences in any outcome measures or radiographic findings. Patients receiving metal liners had significantly elevated metal ion measurements. At most recent follow-up, compared to the polyethylene control group, patients receiving a metal on metal bearing had erythrocyte cobalt levels were eleven times elevated (median 1.4 μg/L (metal) vs 0.12 μg/L (poly), p< .001). Urine cobalt levels were thirty-nine times elevated (median 11.4 μg/L/day (metal) vs 0.29 μg/day (poly), p< .001) and urine chromium levels were twenty-eight times elevated (median 4.75 μg/day (metal) vs 0.17 μg/day (poly), p< .001). Additionally the metal ion levels reached an early steady state level and did not decrease over time. (Erythrocyte Co (μg/L): 1.29 (6 mos), 1.20 (1 yr), 1.0 (2 yr), 1.10 (3 yr), 1.35 (4 yr), 1.40 (5 yr)).

Both cobalt and chromium ion measurements were significantly elevated in the blood and urine of the patients randomised to receive the metal on metal THA at all time intervals. Contrary to previous reports, in 34% of patients with a metal liner, metal ion (erythrocyte cobalt) elevation was still increasing at latest follow-up, and in the overall metal on metal patient cohort, metal ion median levels were not decreasing over time. As in polyethylene wear data, metal ion results are not necessarily generalizable, but are bearing design specific.

Background: To present the experience of three centres in the surgical management of scoliosis in patients with Prader-Willi syndrome¹, and to describe the associated complications. A retrospective case series reviewing treatment type, surgical outcomes and complications with a review of the literature

Methods: There were 15 patients treated surgically in the three centres over an eleven year period. The average age at initial surgery was 9.6 (5 to 16+8) yrs. Minimum follow-up from index procedure was 28 months. 5 underwent posterior spinal fusion, 2 had anterior fusion alone and 2 had combined anterior/ posterior fusions as their index procedure. 6 patients were initially managed with growing rod constructs. Outcome measures included fusion rate, curve progression and complication rate.

Results: 11 patients achieved a solid fusion. 2 patients were still undergoing the lengthening process and were thus unfused. 1 patient had broken instrumentation with pseudarthrosis, and one patient not fit for final fusion remained without implants. No curve progression was seen in the 11 fused spines. Progressive kyphosis and scoliosis were noted in the two ongoing lengthening patients. There were 17 revision procedures not including planned lengthenings, with a total of 59 surgical procedures. 5 rod breakages occurred in the growing-rod patients. There were 11 infections (4 deep) in 7 patients. There were 6 respiratory complications, 3 requiring ventilatory support. One patient had post-operative neurological deterioration requiring re-exploration and who had grade 3 paraparesis at final follow-up. In total there were 36 complications (240%)

Conclusion: The outcome of surgical management of scoliosis in Prader-Willi syndrome is adversely affected by the obesity and respiratory difficulties of the patients and complications abound². The use of growing constructs, whilst enabling the management of the growing child, greatly increases the risk of implant failures. Their use in Prader-Willi requires careful consideration.

Objective To assess the validity of Somatosensory Evoked Potential (SSEP) monitoring in identifying potential spinal cord vascular damage resulting from segmental artery ligation in anterior spinal deformity correction.

Design SSEP monitoring was undertaken in patients deemed at risk of spinal cord vascular injury during corrective surgery. The segmental vessels of the vertebral bodies to be instrumented were identified. Baseline SSEPs were obtained prior to application of non-crushing microvascular clamps. After ten minutes of occlusion, further SSEP recordings were made. Surgery proceeded with either, vessel ligation and division allowing anterior instrumentation, or vessel sparing anterior release.

Subjects 22 patients were included; 7 had Scheuermann’s hyperkyphosis and 15 had scoliosis (11 idiopathic, 3 syndromic, 1 neuromuscular). Perceived risk was defined by the presence of hyperkyphosis, abnormal neurological examination or radiologically identified spinal cord anomaly.

Outcome Measures A drop of 30% from baseline reading was taken as significant. Post-operative neurological outcome was correlated with intra-operative signal change and alteration in planned surgery.

Results There was no significant drop in post-clamping SSEPs in the hyperkyphotic patients. In 3 scoliosis patients anterior instrumentation was abandoned and a release was performed. Staged posterior instrumentation followed. In a further 2, anterior instrumentation proceeded but in a modified fashion. The remaining 10 patients had no significant drop and underwent the surgery as planned. No patient sustained a neurological injury.

Conclusions SSEP monitoring is safe in assessing the apparent contribution of segmental vessel blood supply to the spinal cord in spinal deformity surgery. It has allowed timely alteration of planned surgical procedures that potentially may have caused vascular spinal cord injury.

Introduction: The long term integrity of the intervertebral disc following repair of pars interarticularis defects in the lumbar spine is uncertain. This study was undertaken to clarify this issue.

Materials and Methods: 26 patients with symptomatic lumbar spondylolyis underwent a modified Scott repair of the defects, between 1979 and 1993. The early results of these patients were presented to the British Scoliosis Society in 1998. Ten patients have been recalled and reviewed clinically and by MRI investigation at a mean follow-up of 10 years.

Results: Eight of the 10 patients are completely asymptomatic and the MRI appearances are normal. The remaining two patients are symptomatic; one has MRI evidence of disc degeneration and the other has normal MRI appearances.

Conclusion: Repair of the pars interarticularis defect in symptomatic spondylolysis gives excellent symptomatic relief following surgery. This long term review indicates that it protects the integrity of the adjacent intervertebral disc.