Introduction: Metastatic spinal disease continues to be a challenge in the management of patients with advanced malignancy. Anterior en bloc spondylectomy and stabilisation, a more extensive procedure, is favoured as it is thought to provide a curative resection and improve the overall outcome (Tomita et al,2002; Wiegel, 1999).

Aim: The aim of this study was to see if there is still a role for extensive posterior decompression (Wide laminectomy and transpedicular decompression) with stabilisation in the treatment of these patients which is the mode of treatment used in our institution and favoured by some others (Bauer, 1997)

Patients and Methods: We retrospectively reviewed a cohort of patients treated in our institute by extensive posterior decompression and stabilisation between 2000 to 2006. We excluded patients having haematological primaries and anterior surgery and those with inadequate data.

Outcome measures used were post operative mortality, Post operative improvement in Frankel score, level of pain perception, level of mobility and ability to perform activities of daily living.

Results: 52 patients had posterior surgery with Colarado instrumentation being used in a majority. There was a slight male preponderance with an average age of 67 years. The mean length of follow up was 12 months.57% patients were dead at last review. 52 % patients showed an improvement in Frankel scores. There was a significant decrease in analgesic requirement post operatively with an improvement in pain scores. Similarly there was an improvement in the ability to perform activities of daily living and the level of mobility. No major surgical complications were noted bar a few superficial wound infections. Revision surgery was done in 6 cases. In 2 it was for a tumour recurrence, for broken rods in 2 and converted to anterior in 2. There were 4 immediate peri operative deaths.

Conclusion: Our results are comparable to Bauer et al, 1997 and other series. Posterior spinal surgery is very much a viable treatment option to treat selected cases with metastatic spinal disease. It avoids all the complications and morbidity of anterior surgery while producing an overall improvement in pain, the quality of life, level of mobility and neurological status.

The possibility that AIS aetiology involves undetected neuromuscular dysfunction is considered likely by several workers [1,2]. Yet in the extensive neuroscience research of idiopathic scoliosis certain neurodevelopmental concepts have been neglected. These include [3]:

a CNS body schema (“body in the brain”) for posture and movement control generated during development and growth by establishing a long-lasting memory, and

During normal development the CNS has to adapt to the rapidly growing skeleton of adolescence, and in AIS to developing spinal asymmetry from whatever cause. Examination of publications relating to the CNS body schema, parietal lobe and temporo-parietal junction [4,5] led us to a new concept: namely, that a delay in maturation of the CNS body schema during adolescence with an early AIS deformity at a time of rapid spinal growth results in the CNS attempting to balance the deformity in a trunk that is larger than the information on personal space (self) already established in the brain by that time of development. It is postulated that this CNS maturational delay allows scoliosis curve progression to occur – unless the delay is temporary when curve progression would cease. The maturational delay may be primary in the brain or secondary to impaired sensory input from end-organs [6], nerve fibre tracts [2,7,8] or central processing [9,10]. The motor component of the concept could be evaluated using transcranial magnetic stimulation [11].

Conclusion: Any maturational delay of the CNS body schema could impair postural mechanisms in girls and boys with or without early AIS deformity. The “body in the brain” concept adds a particular CNS mechanism (maturational delay) to the neuro-osseous timing of maturation (NOTOM) hypothesis for the pathogenesis of AIS [12,13]. The NOTOM hypothesis states that there are more girls than boys with progressive AIS because of different developmental timing of skeletal maturation and postural maturation between the sexes in adolescence [12,13].

In subjects with lumbar, thoracolumbar or pelvic tilt scoliosis no pattern of structural leg length inequality has been reported [1]. Forty-seven girls of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spinal scoliosis – lumbar (LS) 17, or thoracolumbar (TLS) 30 (mean Cobb angle 16 degrees, range 4–38 degrees, mean age 14.8 years, left curves 25). The controls were 280 normal girls (11–18 years, mean age 13.4 years). Anthropometric measurements were made of total leg lengths (LL), tibiae (TL) and feet (FL) by one observer (RGB) and asymmetries calculated for LL, TL and FL, as absolutes and percentage asymmetries of right/left lengths. There are no detectable changes of absolute asymmetries with age for LL, TL or FL in scoliotic or normal girls. Asymmetries are found in scoliotic girls compared with normals with relative lengthening on the right for each of LL (0.95%) and TL (0.99%) (each p< 0.001), but not FL (0.38%).

Conclusion: The relative lengthenings in the right leg are unrelated statistically to the severity or side of the lower spinal scoliosis; the cause is unknown and may be related to posture – free standing on the right leg [2] – to neuromuscular mechanisms, or to primary skeletal changes in growth plates of femur(s) and tibia(e).

Study Design. Randomized, single blind, Quasi-experimental trial.

Objective. To investigate whether immediate physiotherapy post lumbar micro-discectomy enables patients to become independently mobile more rapidly with no increase in risk of complications

Summary of Background Data. Although studies have demonstrated the efficacy of rehabilitation post lumbar discectomy, none have looked at physiotherapy commencing immediately post operatively.

Methods. A total of thirty patients were randomized to an immediate group commencing physiotherapy within two hours post-operatively or a control group receiving physiotherapy first day post-operatively. Outcome measures included the time taken for the patient to become independently mobile post-surgery, Oswestry Disability Index and pain scores (VAS and short form McGill) collected pre-operatively, post-operatively at four weeks, and three months.

Results. The results indicated significantly reduced time to independent mobility (p=0.009) and return to work (p=0.002) in the immediate group. There was no significant difference in disability and pain scores at four weeks and three months between the groups. Early mobilisation did not result in increased complications.

Conclusions. Immediate physiotherapy following first time single level lumbar micro-discectomy enables patients to become independently mobile more rapidly and return to work sooner. Immediate physiotherapy may enable patients to experience earlier discharge with associated cost benefits to healthcare.

In schoolchildren screened for scoliosis about 40% have minor, non-progressive, lumbar scolioses secondary to pelvic tilt with leg-length and/or sacral inequality [1] not reported with preoperative thoracic curves [2]. Forty-nine of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spinal scoliosis with measurable radiological sacral alar and hip tilt angles – lumbar scoliosis 18, thoracolumbar scoliosis 31 (girls 41, boys 8, mean Cobb angle 16 degrees, range 4–38 degrees). In standing full spine antero-posterior radiographs measurements were made of Cobb angle and pelvic asymmetries as sacral alar and iliac heights (left minus right). From anthropometric measurements derivatives were calculated as ilio-femoral length (total leg length minus tibial length) and several length asymmetries, namely: ilio-femoral length asymmetry, total leg length inequality and tibial length asymmetry (all left minus right). Ilio-femoral length asymmetry correlates significantly with sacral alar height asymmetry (girls negatively r= − 0.456, p=0.002, boys positively r=0.726 p=0.041) but not iliac height asymmetry (girls p=0.201) from which three types are identified. Total leg length inequality but not tibial length asymmetry in the girls is associated with sacral alar height asymmetry (r= − 0.367 p=0.017 & r=0.039 p=0.807 respectively). Interpretation is complicated by total leg lengths each including some ilium in which there is asymmetry [3]. But lack of association between ilio-femoral length asymmetry and iliac height asymmetry suggests that the femoral component is more important than iliac component in determining the associations between sacral alar height asymmetry and each of ilio-femoral length asymmetry and total leg length inequality.

Conclusions:

Sacral alar height asymmetry and leg length asymmetries. The evidence suggests that sacral alar height asymmetry is not secondary to the leg length inequalities at least in most girls (negative correlations) and is more likely to result from primary skeletal changes in femur(s) and sacrum.

Patterns of extra-spinal skeletal length asymmetry have been reported for upper limbs [1] and ribcage [2] of patients with upper spine adolescent idiopathic scoliosis. This paper reports a third pattern in the ilia. Seventy of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spine scoliosis – lumbar (LS), thoracolumbar (TLS), or pelvic tilt scoliosis (PTS). Radiologic bi-iliac and hip tilt angles were both measurable in 60 subjects: LS 18, TLS 31, and PTS 11 (girls 44, boys 16, mean age 14.6 years). Cobb angle (CA), apical vertebral rotation (AVR) and apical vertebral translation from the T1-S1 line (AVT) were measured on standing full spine radiographs (mean Cobb angle 14 degrees, range 4–38 degrees, 33 left, 27 right curves). Bi-iliac tilt angle (BITA) and hip tilt angle (HTA) were measured trigonometrically and iliac height asymmetry calculated as BITA minus HTA (corrected BITA=CBITA) and directly as iliac height asymmetry. Iliac height is relatively taller on the concavity of these curves (p< 0.001). CBITA is associated with Cobb angle, AVR and AVT (each p< 0.001).

Conclusion: The relatively taller concave ilium may be 1) real from primary skeletal changes or asymmetric muscle traction on iliac apophyses [3], or 2) apparent from rotation/torsion at the sacro-iliac joint(s).

Introduction: Lumbar spine morphology is well described in healthy children but has not been described in children with Osteogenesis Imperfecta (OI).

Aims: To look at lumbar bony morphometry in OI children and to consider the importance of these factors in spinal surgery in these children.

Methods: 21 lumbar vertebrae (from L3–5) of 7 OI (6 OI type 3 and 1 OI type 4) children with scoliosis were analysed using Reformatted Computer Tomographic scans. The following measurements obtained: Spinal canal diameters, Transverse pedicle width, Total pedicle length, Pedicle root length, Transverse pedicle angle and Sagittal pedicle angle. Results are compared with previously published data of normal age-matched lumbar spine measurements.

Results: The mean age was 12 years (range 7–18 years). 6 females and 1 male. All had spondylolisthesis at L5-S1. Results were analysed by Wilcoxon Signed Rank test (nonparametric test). The transverse pedicle width was significantly narrower at all 3 levels (p< 0.01). Transverse pedicle angle was significantly less angled at all 3 levels (L3 p=0.04, L4 & L5 p< 0.01) whilst the sagittal pedicle angle was significantly more angled at all 3 levels (p< 0.01). Spinal canal diameter (AP) was significantly increased at all 3 levels (L3 & L5 p< 0.01, L4 p=0.02). And no significant differences in spinal canal transverse diameter and total pedicle length. Pedicle root length Significantly longer at all 3 levels (L3 & L4 p< 0.05, L5 p< 0.01). All children had grade-I spondylolisthesis at L5/S1.

Conclusions: A longer pedicle root with a narrower transverse diameter (and thinner cortices) and a reduced transverse angle is essential knowledge when passing pedicle screws in the lumbar spine in children with OI. This is a difficult technique and its safety requires further evaluation.

In idiopathic scoliosis the detection of extra-spinal left-right skeletal length asymmetries in the upper limbs, ribs, ilia and lower limbs [1–7] begs the question: are these asymmetries unconnected with the pathogenesis, or are they an indicator of what may also be happening in immature vertebrae of the spine? The vertebrate body plan has mirror-image bilateral symmetries (mirror symmetrical, homologous morphologies) that are highly conserved culminating in the adult form [8]. The normal human body can be viewed as containing paired skeletal structures in the axial and appendicular skeleton as a) separate left and right paired forms (e.g. long limb bones, ribs, ilia), and b) united in paired forms (e.g. vertebrae, skull, mandible). Each of these separate and united pairs are mirror-image forms – enantiomorphs. In idiopathic scoliosis, genetic and epigenetic (environmental) mechanisms [9–11] may disturb the symmetry control of enantiomorphic immature bones [12–13] and, by creating left-right endochondral growth asymmetries, cause the extra-spinal bone length asymmetries, and within one or more vertebrae create growth conflict with distortion as deformities (= unsynchronised bone growth concept) [14].

Conclusion: This enantiomorphic disorder concept applied to the axial skeleton during infancy, juvenility and adolescence – through reductionism into the molecular mechanisms of growth plate responses to different hormones at successive phases of development – provides a new theoretical insight to explain the whole body deformity of AIS. The concept suggests preventive surgery on spine and ribs.

Introduction: Lumbar spine morphology is well described in healthy children but has not been described in children with Osteogenesis Imperfecta (OI).

Aims: To look at lumbar bony morphometry in OI children and to consider the importance of these factors in spinal surgery in these children

Methods: 21 lumbar vertebrae (from L3-5) of 7 OI (6 OI type 3 and 1 OI type 4) children with scoliosis were analysed using Reformatted Computer Tomographic scans. The following measurements obtained: Spinal canal diameters, Transverse pedicle width, Total pedicle length, Pedicle root length, Transverse pedicle angle and Sagittal pedicle angle. Results are compared with previously published data of normal age-matched lumbar spine measurements

Results: The mean age was 12 years (range 7-18 years). 6 females and 1 male. All had spondylolisthesis at L5-S1. Results were analysed by Wilcoxon Signed Rank test (nonparametric test). The transverse pedicle width was significantly narrower at all 3 levels (p< 0.01). Transverse pedicle angle was significantly less angled at all 3 levels (L3 p=0.04, L4 & L5 p< 0.01) whilst the sagittal pedicle angle was significantly more angled at all 3 levels (p< 0.01). Spinal canal diameter (AP) was significantly increased at all 3 levels (L3 & L5 p< 0.01, L4 p=0.02). And no significant differences in spinal canal transverse diameter and total pedicle length. Pedicle root length Significantly longer at all 3 levels (L3 & L4 p< 0.05, L5 p< 0.01). All children had grade-I spondylolisthesis at L5/S1.

Conclusions: A longer pedicle root with a narrower transverse diameter (and thinner cortices) and a reduced transverse angle is essential knowledge when passing pedicle screws in the lumbar spine in children with OI. This is a difficult technique and its safety requires further evaluation.

Background: The study evaluates the inter-relationships between Cobb angle (CA), apical vertebral rotation (AVR), apical vertebral translation (AVT) and maximal angle of trunk inclination (max ATI). The effects of sex, curve laterality, curve type and apical levels will be studied

Methods: This is a study of consecutive pre-operative AIS patients. There are 122 pre-operative AIS patients (106 thoracic, 16 thoracolumbar), with a mean age of 15.6 years. From the pre-operative AP radiograph, CA, AVR (Perdriolle) and AVT are measured. The max ATI is measured using the Scoliometer with the patient in a standing forward bending position. Ratios between the measurements are calculated to allow comparison between different curve types and curves at different apical levels.

Results: For a given Cobb angle, each of AVR, AVT and max ATI are largest in King type IV curves, less in King type III curves and smallest in King type II curves (p=0.001 to 0.015). For curves without a significant compensatory curve, for a given AVR, the max ATI reduces significantly as the curve apex passes caudally (p=0.002 to 0.019). Sex and curve laterality are not significant factors.

Conclusion: It is suggested that as a curve develops, the interaction between the measurements in different planes may be responsible for determining the curve type (presence or absence of a compensatory curve). The smaller surface hump as the curve apex passes caudally is probably due to the transition from fixed ribs to floating ribs to no ribs. These finding also have implications for surgery. In King type IV and III curves, the emphasis should be on correcting translation and derotation perhaps with a primary costoplasty whilst in King type II curves, the emphasis should be on the correct selection of fusion levels and achieving a balanced spine.

Background: To assess the potential for Quantec imaging to save radiographs in the follow-up of patients with early onset scoliosis. This is a group of patients who often have many radiographs due their age at diagnosis.

Methods: This is a prospective cohort study. Twenty-four children with early onset scoliosis are identified. They all have a minimum of three simultaneous radiographs and Quantec scans as part of routine follow up for their scoliosis curves. There are 15 males and 9 females (22 thoracic, 1 thoracolumbar, 1 lumbar). Mean age at diagnosis is 3 years (range 1–4.8 years). The Cobb angle of the major curve is measured from each radiograph and compared with the Q-angle using Bland-Altman plots and linear regression analysis.

Results: The mean Cobb angle was 30° and the mean Q-angle 19°. The correlation coefficient was 0.68 (p< 0.05). In curves with Cobb angle < 30°, The Bland-Altman plots show a close scatter with a mean difference of 3.4°. It was calculated that this could have safely saved 18 radiographs in 14 patients. In curves > 30°, there was a large scatter and a mean difference between Cobb angle and Q-angle of 20.1°.

Conclusion: In early onset scoliosis, curves with Cobb angle less than 30° can be safely followed clinically and with the Q-scan reducing the number of radiographs required. Curves with Cobb angle greater than 30° cannot be reliably observed with Quantec scans alone.

Background: In preoperative thoracic (TC) and thoracolumbar (TLC) AIS curves to evaluate periapical rib-vertebra angle asymmetry [1] and rib-spinal angle asymmetry in relation to the spinal deformity and the 4th column support of the spine [2].

Methods: Consecutive preoperative AIS patients having spinal instrumentation and fusion were assessed using radiographs and ultrasonographs. Twenty-eight preoperative patients with AIS were studied (TC 19, apex T8-9 in 15, TLC 9, apex T12 in 2, L1 in 7, mean Cobb angle 51 degrees). In AP radiographs the following were measured by one observer (RGB): Cobb angle (CA), apical vertebral rotation (AVR) and apical vertebral translation (AVT) from the T1-S1 line; in TC at 6 levels about the apical vertebra (3 above, at and 2 below) for each of 1) rib-vertebral angles (RVAs) and difference (RVAD=concave minus convex RVA), 2) rib-spinal angles (RSAs) to the T1-S1 line and difference (RSAD), and 3) vertebral tilt; and in TLC the RVAs, RVADs, RSAs and RSADs of ribs 11 & 12. The ultrasound apical spine-rib rotation difference (SRRD) was obtained as a measure of transverse plane rib deformity. With the subject in a prone position and head supported, readings of laminal rotation (LR) and rib rotation (RR) were made on the back at 12 levels by one of two observers (RKA, ASK) using an Aloka SSD 500 portable ultrasound machine with a veterinary long (172mm) 3.5 MHz linear array transducer. The maximal difference between LR and RR about the curve apex was calculated as the apical spine-minus-rib rotation difference (SRRD).

Results: Thoracic curves. The RVADs (but not the RVAs, RSAs or RSADs) only at 2 & 3 levels above the apex correlate significantly with each of CA (p=0.054), AVR (p=0.047), AVT (p=0.014, after controlling for CA p=0.131) and vertebral tilt (p=0.032) but not SRRD (all two levels above apex). Thoracolumbar curves. The 11th RSAD (but not RVAD or RSAs) correlates significantly with each of AVR (r= −0.776, p=0.014, after controlling for CA p=0.022) and SRRD (r= −0.890, p=0.001, after controlling for CA p=0.003) that together correlate significantly (r=0.672, p=0.048).

Conclusion: In TC supra-apical rib asymmetry (RVAD) in sternally-stabilized [2] and longest levers of the sternal-rib complex is associated with spinal deformity; in TLC supra-apical rib asymmetry (11th RSAD) is associated with transverse plane deformity of each of the apical vertebra (mainly L1) and 12th ribs. These rib associations, probably secondary to the spinal deformity, may involve a primary rib component in the 4th spinal column. The prognostic value of supra-apical RVAD and RSAD for progressive AIS needs to be evaluated.

Background: It is generally accepted that surgical correction in adolescent idiopathic scoliosis (AIS) is largely for cosmesis. Scoliometer measurements of back surface asymmetry and rasterstereographic methods are used to attempt to quantify the surface deformity, These methods are also used to determine the ‘success’ of surgery. This study objectively evaluates trunk cosmesis from pre-operative photographs.

Methods: This is a prospective cohort study. Twelve pre-operative girls with thoracic AIS had standard photographs taken in the standing and forward bending positions. The mean Cobb angle is 74°, mean age 13.7 years. Twenty observers were selected by their profession (3 Spinal Consultants, 4 Orthopaedic Specialist Registrars, 4 nurses, 4 medical illustrators and 5 lay-people). Each patient’s photographs were arranged on a single sheet and the observer was asked to arrange the patients in order of cosmesis and having done this to give a score between 0 (best) and 100 (worst) for overall cosmesis.

Results: There was no good agreement either in the ranking or the scoring for any of the groups of observers. Some observers agreed quite well whilst others ranked and scored much differently to the ‘mean’.

Conclusion: Cosmesis is a spectrum and is most definitely in the eye of the beholder with wide disagreement between individuals both for ranking and scoring cosmesis. We must identify the components of trunk cosmesis (for the majority of observers) so that we can quantify these and produce a score to reflect what we are trying to treat. Only then will we be able to assess the results of our treatments.

Objective: We evaluated retrospectively whether there is a role for selective posterior thoracic correction and fusion in double major curves with third generation instrumentation systems.

Methods: In a retrospective review the radiographs of 36 patients with Lenke 3C type curve patterns and having had a selective posterior thoracic correction and fusion with either the Cotrel-Dubousset instrumentation or the Universal Spine System, were evaluated in terms of coronal and sagittal plane balance, curve flexibility, and curve correction with a minimum follow up of two years. Postoperative coronal spinal decompensation was investigated with respect to preoperative radiographic parameters on standing AP, thoracic and lumbar supine side-bending as well as lateral standing radiographs. Coronal spinal decompensation was defined as plumbline deviation of C7 of more than 2 cm with respect to the center sacral vertical line within two years postoperatively. Two groups of patients were analyzed.

Results: 26 patients (72%) showed satisfactory frontal plane alignment by means of C7 plumb line deviation (group A, 1.2 cm to the left), whereas 10 patients (28%) showed coronal spinal decompensation (group B: 2.7 cm to the left; p=0.003). Group differences, could be revealed for lumbar apical vertebral rotation (Perdriolle) (p=0.02, A: 16°, B: 22°) and the percentage correction (derotation) of lumbar apical vertebrae in lumbar supine side-bending films in comparison to AP standing radiographs (p=0.002, A: 49%, B: 27%). Average thoracic curve correction was 51% in group A and 41% in group B (p=0.05). Average lumbar curve correction was 34% in group A and 23% in group B (p=0.09).

High correlation was revealed between postoperative decompensation and derotation of lumbar apical vertebrae (P=0.62, p< 0.001) with a critical value of 40%. A 2x2 table showed that in patients with lumbar apical vertebral derotation of less than 40% specificity was 90% with regard to postoperative decompensation.

Conclusion: Lumbar apical vertebral derotation of less than 40%, determined on lumbar supine side-bending films in comparison to AP standing radiographs, provided the radiographic prediction of postoperative coronal spinal imbalance. We advice close scrunity of the transverse plane in the lumbar supine side-bending film when planning surgical strategy.

Objective: To identify radiographic parameters which could predict postoperative spinal decompensation in the frontal plane in King type II adolescent idiopathic scoliosis after posterior thoracic correction and fusion with third generation instrumentation systems.

Design: Retrospective radiographic analysis.

Subjects: The radiographs of 36 patients with King type II adolescent idiopathic scoliosis (AIS) who had had posterior thoracic correction and fusion, either with the Cotrel-Dubousset instrumentation (CDI) or the Universal Spine System (USS), were evaluated in terms of frontal and sagittal plane balance, curve flexibility, and curve correction with a minimum follow up of two years. Postoperative spinal decompensation in the frontal plane was investigated with respect to preoperative radiolographic parameters on standing upright AP, thoracic and lumbar supine side-bending as well as lateral standing radiographs. Spinal decompensation in the frontal plane was defined as plumbline deviation of C7 of more than 2 cm with respect to the centre sacral line within two years postoperatively. Two groups of patients were analyzed.

Outcome measures: 26 patients (72%) showed satisfactory frontal plane alignement by means of C7 plumb line deviation (group A, 1.2 cm to the left), whereas 10 patients (28%) showed spinal decompensation (group B: 2.7 cm to the left). Group differences were significant (p=0003).

Results: The two groups were found statistically equivalent in terms of preoperative C7 plumbline deviation (p=0.112, group A: 0.8 cm, group B: 0.7 cm to the left), thoracic cobb angles (p=0.093, group A: 56°, group B: 62°), lumbar cobb angles (p=0.115, group A: 42°, group B: 47°), lumbar curve flexibility (p=0.153, group A: 78%, group B: 67%); thoracic kyphosis (p=0.153) and lumbar lordosis (p=0.534) and age at operation (p=0.195), Significant group differences, however could be revealed for thoracic curve flexibility (p=0.03, group A: 43%, groupB: 25%) and the percentage of derotation of lumbar apical vertebrae in lumbar supine side-bending films in comparison to AP upright standing radiographs (p=0.002, group A: 49%, group B: 27%). Average thoracic curve correction was 51% in group A and 41% in group B. Group differences were significant (p=0.05). Average lumbar curve correction was 34% in group A and 23% in group B (p=0.09). No group differences could be revealed for postoperative thoracic kyphosis and lumbar lordosis measurements. Logistic regression analysis with C7 plumbline deviation of more than 2 cm postoperatively as the dependent variable yielded the amount of lumbar apical vertebral derotation in lumbar supine side-bending films as the only risk-factor (p=0.007).

Conclusion: Fixed lumbar rotation, measured in terms of the percentage of derotation of lumbar apical vertebrae in lumbar supine side-bending films in comparison to AP upright standing radiographs, provided the radiographic prediction of spinal decompensation in the frontal plane after posterior thoracic correction and fusion of King II type curves.

Objective: To assess the intra- and inter-observer reproducibility of a number of commonly used radiological measurements in pre- and post-operative patients with thoracic adolescent idiopathic scoliosis (AIS). Reproducibility of measures other than Cobb angle and vertebral rotation have not been studied and particularly there are no reports of reproducibility in patients after instrumentation.

Design: Repeat measurement of radiographs before and after surgery by 2 observers.

Subjects: 30 patients with thoracic AIS were selected from a scoliosis database at random: 15 treated with posterior USS and 15 with anterior instrumentation (8 Zielke / 7 anterior USS).

Outcome measures: The pre-operative AP radiograph, supine lateral bending radiograph and the post-operative AP radiograph at 6 months were selected for each patient. Two observers (MM beginner, AAC experienced) obtained the following measurements from the radiographs: Cobb angle, apical vertebral rotation (AVR, Perdriolle), apical vertebral translation (AVT) to the T1-S1 line, and frontal plane imbalance (FPI). With all marks removed, the radiographs were re-measured by each observer at least one week later. Repeatability was calculated using the method described by Bland and Altman (BMJ 1996). This method is a widely accepted anthropometrical technique but has not previously been used for assessing scoliosis measurements. It was assessed as 95% reproducibility. The co-efficient of reliability (r) expresses the proportion of the observed variability that is not due to error, i.e. higher is better. This was calculated as a means of assessing the usefulness of our measurements and to enable us to compare them.

Results: Intra-observer repeatability (MM vs. AAC): Whether the instrumentation was anterior or posterior had no effect on Cobb angle, AVT or FPI repeatability. AVR however was worse for posterior instrumentation 19° vs. 12°. “r” was > 90% for Cobb angle, AVT and PFI. But, for AVR r measured pre-op 52-92% and post-op 38–69%.

There was no relationship between repeatability and the measurement size.

Conclusions: Measurement reproducibility / error is slightly worse than previously suspected. E.g. a 5–6° curve progression is thought to be significant. We suggest that this could be due to measurement error and the figure should be 6–8°. There is no learning curve for the technique used to measure Cobb angle, AVT and FPI. AVR (Perdriolle) however requires experience. Cobb angle measurement error post-op is similar to pre-op. The Perdriolle method has greater error post-op especially in posterior instrumentation.

Objective: To assess the radiological and back surface correction achieved following anterior USS in the treatment of thoracic adolescent idiopathic scoliosis (AIS).

Design: Prospective study of back surface correction, retrospective radiological review.

Subjects: 14 patients with thoracic AIS (age 11–18 yrs) were treated with anterior USS between 1995 and 2000. There are 12 females and 2 males, all with 2 year follow-up. 8 patients have complete surface data. Data from a further 6 patients will shortly be available as they reach 2 year follow-up.

Outcome measures: Cobb angle, apical vertebral rotation (AVR), apical vertebral translation (AVT), frontal plane imbalance, kyphosis and lordosis were measured from the radiographs. A Scoliometer was used to assess the maximal angle of trunk inclination (max ATI) in the thoracic region. All measurements were obtained before surgery and at 8 weeks, 1 year and 2 years after surgery. Complications were recorded.

Results: Significant initial corrections are observed for each of: Cobb angle (51%, p< 0.001), AVR (40%, p=0.003),AVT (64%,p< 0.001),maxATI (47%,p=0.001). There is no significant correction loss during the 2 year follow-up. Three patients had spinal imbalance (> 2cm) before surgery with one patient after surgery. The kyphosis significantly increased from 24° to 29° immediately after surgery with no significant change during follow-up. There was no change in lordosis. There were no neurological complications and no instrumentation failures were observed. In two cases the upper screw partially pulled out of T5 with some loss of correction.

Conclusions: Anterior scoliosis correction for thoracic AIS achieves good and stable radiological and particularly back surface corrections (max ATI – 47% compared with 22% correction after posterior surgery). Rigid anterior instrumentation has eliminated the 20% rod failure seen with Zielke. New techniques for preventing upper screw pull out will be discussed and new retractor systems allow smaller thoracotomies. There remains a small but significant increase in kyphosis which is less of a problem in the thoracic spine than at the thoracolumbar junction where anterior scoliosis correction is most commonly advocated.

Anterior instrumentation for thoracic AIS has advanced to a point where it can be widely adopted, particularly if the patient expresses concerns regarding the rib hump or is hypokyphotic.

Objective: To report a new method for reduction and stabilisation of a high grade isthmic spondylolisthesis.

Design: Case study

Subjects: A 14 year old boy presented with persistent low back pain from an L5/S1 grade 3 isthmic spondylolisthesis. MRI scan confirmed the L5/S1 spondylolisthesis with a degenerative disc at this level and healthy discs above. After discussion with the patient and his family, it was decided to attempt to reduce the spondylolisthesis.

Operation: Surface SSEP and CMEP were performed throughout the procedure. The patient was positioned prone on a Montreal frame and a standard posterior, midline approach made from L4 to the sacrum with careful preservation of the L4/5 facet joints. Wide laminectomy at L5, with partial laminectomy of the superior aspect of S1 and the inferior aspect of L4 allowed visualisation of the L5, S1 and S2 nerve roots. The postero-superior aspect of S1 was removed with an osteotome from each side in preparation for the reduction of L5. An L5/S1 discectomy and end-plate preparation was performed in preparation for a PLIF. Reduction was not possible at this stage. The wound was closed and the patient re-positioned supine. A transperitoneal approach was made to L5/S1 allowing removal of the anterior disc protrusion and associated fibrosis. Following careful removal of this material, L5 could be translated posteriorly. The anterior approach was closed and the patient was repositioned prone with the posterior wound re-opened. Pedicle screws were inserted into S1 bilaterally but it was not possible to get pedicle screws into the deep seated and dysplastic L5 pedicles so screws were placed in the L4 pedicles. Contoured rods (5mm) were placed into the S1 screws. After very mild distraction, the screw in L4 on one side was reduced to the rod allowing placement of an L5 pedicle screw on the opposite side. This process was repeated to allow placement of a second L5 pedicle screw on the other side. The plan was to the remove the L4 pedicle screws to avoid fusing the L4/5 level. Unfortunately, due to the dysplastic pedicles, the L4/5 facet joints were destroyed by the pedicle screw insertion and an L4 to S1 fusion performed. Iliac crest bone graft was harvested for the posterolateral fusion and also used to fill two Rotafix cages inserted into the reduced L5/S1 disc space. A radiograph at this stage confirmed reduction of the L5/S1 spondylolisthesis. Total estimated blood loss was 4200ml and a cell saver system was used throughout the operation. The patient had no neurological deficit after surgery and made an uneventful recovery being discharged 4 days after surgery. There was a haematoma/seroma beneath a well healed wound noted at the six week clinic appointment but no other complications have been observed. He is delighted with his improved cosmetic appearance and his back pain has resolved.

Conclusions: We feel this single operation, three stage procedure is a safe way of reducing a high grade spondylolisthesis.

Giant Cell Tumour of the Tendon Sheath is a benign tumour of synovial origin most frequently affecting the upper limb. Up to 11% exhibit radiographic evidence of cortical erosion and intra-osseous expansion. In the upper limb recurrence rates of between 10–50% following excision have been reported. However, GCT-TS is rarely described in the foot and ankle and its behaviour is ill understood.

17 cases of this rarely described tumour in the foot and ankle are presented, describing their clinical presentation, histopathology, treatment and outcome.

Analysis of all cases of histopathologically proven GCT-TS of the foot and ankle from the Oxford Tumour Registry, was conducted between the periods of January 1984 to December 1999.

22 cases were identified of which 17 cases had adequate records to allow analysis of patient demographics, duration of symptoms, preoperative investigations, presumed diagnosis, precise site of origin, post operative complications and recurrence rates

The mean age of presentation was 28 (8–53). 10 cases were female and 7 male. 76% cases occurred in the foot, all of which arose adjacent to the phalanges or heads of the metatarsals. 14% occurred in relation to the ankle or sub-talar joint.

82% presented with a painless swelling. The duration of symptoms ranged from 6 months to 8 years. Only one patient complained of sensory symptoms.

Pre-operative investigations included radiographs in 64% with 3 cases having an additional MRI scan. The MRI scans of GCT-TS have characteristic changes on T1 and T2 images. The presumed preoperative diagnosis was incorrect in 82%.

36% of radiographs taken showed changes including cortical erosion and speckled calcification.

A local excision was performed in 15 cases, an amputation in one and a wide local excision in one case only. There have been no recurrences during the follow up period of between 1–12 years.

GCT-TS of foot and ankle is rare and is commonly misdiagnosed. Despite only a local excision being performed in more than 80% of this series there were no recurrences.

Plain radiographs may show cortical erosion or speckled calcification in up to 36% and MRI is helpful in further defining the anatomy of the lesion, allowing planned excision and reducing the risk of recurrence.