Summary Statement

Repetitive loading of degenerated human intervertebral discs in combined axial compression, flexion and axial rotation, typical of manual handling lifing activities, causes: an increase in intradiscal maximum shear strains, circumferential annular tears and nuclear seperation from the endplate.

Anterior lumbar inter-body fusion (ALIF) is a surgical procedure that is available to chronic lower back pain patients who fail to respond to conservative treatments. Failure to achieve fusion may result in persistence of pain. Fusion of the lumber vertebral segment is more accurately assessed using fine-cut helical Computed tomography (CT) scans (0.25 mm thickness slices). Unfortunately this technique exposes the body to high radiation dose with hazard of increase risk of late malignancy. An alternative imaging tool is radiostereometry (RSA) which developed as a means to determine the magnitude of relative motion between two rigid bodies. In this study we used RSA to detect movement at the fused lumbar segment (ALIF site) during flexion and extension and compare the results obtained with fine-cut helical CT scan using histopathology as final gold standard assessment tool.

ALIF of three levels of lumbar spine (L1-L2, L3-L4, and L5-L6) was done in 9 sheep. The sheep divided into three groups (3sheep each). The first group had RSA assessment immediately, 3, and 6 months after surgery. The second group had RSA immediately, 3, 6, 9 months after surgery. The third group had an RSA immediately, 3, 6, 9, 12 months after surgery All the animals were humanly killed immediately after having the last scheduled RSA (group1, group2, and group 3 sheep were killed 6 month, 9month and 12 months after surgery respectively). This followed by in vitro fine cut CT and histopathology after the animals are scarified. Micro CT scan has been also used to identify the area where histopathology slide should be made to pick up fusion. Fine cut CT scan assessment for all sheep were done. The CT scan has been reported by two independent radiologists. Histopathology has been started and will finish in 2 weeks

RSA showed there was significant increasing stiffness of the spine though the fused segments as the time pass on compare to immediate postoperative assessment. CT scan were done and showed variable fusion though out the spinal segments. Histopathology of all sheep has been started and the results will be available in 2 weeks which will be followed by statistical assessment to decide how accurate RSA compare to CT scan in assessment of fusion.

Long term, secondary implant fixation of Total Disc Replacements (TDR) can be enhanced by hydroxyapatite or similar osseo-conductive coatings. These coatings are routinely applied to metal substrates. The objective of this in vivo study was to investigate the early stability and subsequent bone response adjacent to an all polymer TDR implant over a period of six months in an animal model.

Six skeletally mature male baboons (Papio annubis) were followed for a period of 6 months. Using a transperitoneal exposure, a custom-sized Cadisc L device was implanted into the disc space one level above the lumbo-sacral junction in all subjects. Radiographs of the lumbar spine were acquired prior to surgery, and post-operatively at intervals up to 6 months to assess implant stability. Flourochrome markers (which contain molecules that bind to mineralization fronts) were injected at specified intervals in order to investigate bone remodeling with time.

Animals were humanely euthanized six months after index surgery. Test and control specimens were retrieved, fixed and subjected to histological processing to assess the bone-implant-bone interface. Fluorescence microscopy and confocal scanning laser microscopy were utilized with BioQuant image analysis to determine the bone mineral apposition rates and gross morphology.

Radiographic evaluation revealed no loss of disc height at the operative level or adjacent levels. No evidence of subsidence or significant migration of the implant up to 6 months. Heterotopic ossification was observed to varying degrees at the operated level.

Histology revealed the implant primary fixation features embedded within the adjacent vertebral endplates. Flourochrome distribution revealed active bone remodeling occurring adjacent to the polymeric end-plate with no evidence of adverse biological responses. Mineral apposition rates of between 0.7 and 1.7 microns / day are in keeping with literature values for hydroxyapatite coated implants in cancellous sites of various species.

Radiographic assessment demonstrates that the Cadisc L implant remains stable in vivo with no evidence of subsidence or significant migration. Histological analysis suggests the primary fixation features are engaged, and in close apposition with the adjacent vertebral bone. Flourochrome markers provide evidence of a positive bone remodelling response in the presence of the implant.

Introduction

Different subclinical neurological dysfunction has been reported in adolescent idiopathic scoliosis (AIS), including poor postural control and asymmetric otolith vestibulo-ocular responses when compared with normal controls. The objective of this pilot study is to establish whether abnormal MRI morphoanatomical changes arise in the CNS (brain and vestibular system), among left-thoracic versus right-thoracic AIS when compared with normal adolescent controls, with use of advanced computerised statistical morphometry techniques.

To evaluate the cost-effectiveness IDET relative to circumferential lumbar fusion with femoral ring allograft (FRA).

Cost-effectiveness analysis

Patient-level data were available for patients with discogenic low back pain treated with FRA (n=37) in a randomized trial of FRA vs. titanium cage, and for patients recruited to a separate study evaluating the use of IDET (n=85). Patients were followed-up for 24 months.

Oswestry Disability Index, visual analogue scale, quality of life (SF-36), radiographic evaluations, and NHS resource use. Cost-effectiveness was measured by the incremental cost per quality-adjusted life year (QALY) gained.

Both treatments produced statistically significant improvements in pain, disability and quality of life at the 24-month follow-up. Costs were significantly lower with IDET due to a shorter mean procedure time (377.4 minutes vs. 49.9 minutes) and length of stay (7 days vs. 1.2 days). The mean incremental cost of IDET was -£3,713 per patient; the mean incremental QALY gain was 0.03. At a threshold of £20,000 per QALY the probability that IDET is cost-effective is 1, and the net health benefit is 0.21 QALY per patient treated.

Both treatments led to significant improvements in patient outcomes which were sustained for at least 24 months. Costs were lower with IDET, and for appropriate patients IDET is an effective and cost-effective treatment alternative.

Ethics approval: Ethics committee COREC

This cost-effectiveness analysis was carried out by the York Health Economics Consortium at the University of York, and was funded by Smith & Nephew. Smith & Nephew had no financial or other involvement in the collection or analysis of the data on which the CEA is based.

The purpose of this cohort study is to determine the incidence of all congenital vertebral anomalies detected antenatally through ultrasound. We also reported on the early mortality rate for this patient cohort, as well as the frequency and type of associated congenital anomalies.

The East Midlands and South Yorkshire Anomalies Register consists of data on all voluntary reports of congenital anomalies, from an annual baseline birth rate of 67000 births. We analysed all registered congenital anomalies reported over a 10 year period.

Between January 1997 and January 2007, 108 vertebral anomalies were reported, excluding spinal dysraphism (incidence 0.01%). 61 of these were detected antenatally (56%), 17 were detected postnatally (16%) and in 30 patients, the precise time of diagnosis was unclear (28%).

At the time of analysis January 2007, 45 of 108 patients had died, either in utero or soon after delivery (42%). 12 fetuses remained in utero and 51 infants were alive. The mortality rate for antenatally diagnosed patients was 41% and the majority were electively terminated (72%). 2 fetuses electively terminated had vertebral anomalies in isolation.

There is a relatively high incidence of elective termination of pregnancy as a result of antenatal anomaly ultrasound screening. We have evidence to suggest that foetuses with potentially minor congenital anomalies are being electively terminated at approximately 18 weeks gestation. A structured and timely spinal counselling should be offered once antenatal vertebral anomalies have been identified.

The purpose of this study was to ascertain whether early diagnosis through antenatal ultrasound screening and intervention lead to a reduction in morbidity associated with congenital scoliosis.

Prospective cohort study

All fetuses with vertebral body anomalies detected over a thirteen years period were included. Maternal risk factors, accuracy of antenatal diagnosis, associated fetal anomalies and ultimate outcome are described.

Twenty-four fetuses with congenital hemivertebrae were identified from 39,000 antenatal scans (incidence 0.061%). The mothers' median age at conception was 26 years (range 18-40 years). The median fetal gestational age at diagnosis was 20 weeks (range 18-38 weeks). The median gestational age at delivery was 38 weeks (range 27-40).

Antenatal ultrasound identified eighteen fetuses with a single hemivertebra, six fetuses with multiple hemivertebrae. Eleven patients (50%) have undergone early surgical intervention with median post-natal follow up was 4 years (range 0-9 years). The median age at surgery was 12 months (range 1.2 - 47 months). The median pre-operative Cobb angle was 33 degrees and the median Cobb angle at final follow up was 25 degrees.

In this series 50% of patients required surgical intervention. We felt that pre-natal diagnosis of congenital vertebra abnormally has resulted in early surgical intervention using less complex surgical technique to halt progressive deformity. However, further studies are required to compare the results with the abnormally not detected antenatally.

Study design

Economic evaluation alongside a prospective, randomised, controlled trial from a two-year National Health Service (NHS) perspective.

Study Design

Prospective cohort study.

We report a prospective case-series study to evaluate the results of non-operative and operative treatment of symptomatic unilateral lumbar spondylolysis. Non-operative treatment results in healing in most patients with symptomatic unilateral spondylolysis. Surgery however is indicated when symptoms persist beyond a reasonable time affecting the quality of life in young patients particularly the athletic population.

We treated 41 patients [31 male, 10 female] with suspected unilateral lumbar spondylolysis. Thirty-one patients were actively involved in sports at various levels. Patients with a positive stress reaction on SPECT imaging underwent a strict protocol of activity restriction, bracing and physical therapy for 6 months. At the end of six months, patients who remained symptomatic underwent a Computed Tomography [CT] scan to confirm the persistence of a spondylolysis. Seven patients subsequently underwent a direct repair of the defect using the modified Buck's Technique. Baseline Oswestry disability index [ODI] and Short-Form-36 [SF-36] scores were compared to two year ODI and SF-36 scores for all patients.

In the non-operated group, the mean pre-treatment ODI was 36 [SD=10.5], improving to 6.2 [SD=8.2] at two years. In SF-36 scores, the physical component of health [PCS] improved from 30.7 [SD=3.2] to 53.5 [SD =6.5] [p<0.001], and the mean score for the mental component of health [MCS] improved from 39 [SD=4.1] to56.5 [SD=3.9] [p<0.001] at two years. 20/31 patients resumed their sporting career within 6 months of onset of treatment, a further 4/31 patients returned to sports within one year.

The seven patients who remained symptomatic at six months underwent a unilateral modified Buck's Repair. The most common level of repair was L5 (n=4). The mean pre-operative ODI was 39.4 (SD=3.6) improving to 4.4 (SD=4) at the latest follow-up. The mean score of PCS [SF-36] improved from 29.6 [SD=4.4] to 51.2 [SD=5.2] (SD=5.2) (p<0.001) and the mean score of MCS (SF-36) improved from 38.7 (SD=1.9) to 55.5 (SD=5.4) (p<0.001).

A specific protocol of conservative treatment for patients with a unilateral lumbar spondylolysis resulted in a high rate of success with 83% of patients avoiding surgery. If symptoms persist beyond a reasonable period (i.e. 6 months) and reverse gantry CT scan confirms a non-healing defect of the pars interarticularis one may consider a unilateral direct repair of the defect with good outcome ultimately.

Our prospective observational study of patients treated for Thoracolumbar Adolescent Idiopathic Scoliosis (AIS) by anterior instrumentation aimed at investigating the correlation between the radiographic outcome and the recently-developed scoliosis research society self-reported outcomes instrument (SRS-22) which has been validated as a tool for self-assessment in scoliosis patients. Previous patient based questionnaires demonstrated poor correlation with the radiological parameters.

Introduction: Capasso’s method(CM) has been described in orthopaedic textbooks to be the most sensitive tool for measuring Cobb angle in scoliosis. This method based on “bi-univocal principle” views the scoliosis curve to be an arc of circumference, to be a true reflection of angular values and hence geometrically more valid. However there is no comparative study between the established measurement tools i.e. Oxford cobbometer(OC) & Traditional protractor(TP) vs. CM. Our objectives were to to evaluate the sensitivity of CM against OC & TP in scoliosis and to determine intra & inter-observer reliability of the three methods.

Methods: Three independent blinded observers measured 24 digital AP radiographs of scoliosis on three separate occasions one week apart by CM, OC & TP. The three sets of readings obtained were statistically analysed for intra-observer (Cronbach’s alpha) & inter-observer [Inter-class correlation coefficient(ICC)] reliability.

Results: The mean Cobb angle measured by OC was 42.4(r13-91), by TP was 45.1(r16-89) and by CM was 70.4(r 20-148). The cronbach’s was 0.94 for OC, 0.91 for TP & 0.88 for CM. The ICC was 0.96 for OC, 0.90 for TP & 0.71 for CM. The measurements obtained by CM were higher than the other two methods for all magnitudes of the curves.

Conclusion: CM based on sound geometric principles is perceived to be superior to Cobb angle and has reasonable correlation(Pearson’s®=0.74) with it. However CM overestimates the magnitude of scoliosis as compared to other standard measurement tools. Management decisions based on CM would be inappropriate by current guidelines.

Ethics approval: Not applicable Interest Statement: None

Purpose: To review the existing practice of coding in spinal surgery and ascertain its accuracy for surgical procedures, co-morbidities and complications.

Methods: A retrospective review of 70 cervical and 100 lumbar consecutive spinal surgeries performed since April 2006 was conducted. The clinical coding data and hospital notes were reviewed.

Results: Coding data of 5 cervical spine surgeries were not available. Of the 165 cases, the accuracy of primary procedural codes was 93.9% (90.8% cervical & 96% lumbar). This reduced to 77.6% (75.4% cervical & 79% lumbar) when the accuracy for entire description of performed surgery was considered. Medical co-morbidities were coded appropriately in 64.2% of the patients (55% cervical & 70% lumbar). The procedural codes did not specifically reflect the surgery performed and lacked reproducibility. Surgical levels were coded incorrectly in 9% of the cases. Cervical surgeries were coded as lumbar in 4 and posterior surgery as anterior in 3 cases respectively. The commonly missed co-morbidities were drug allergies, hypercholesterolemia, smoking and alcoholism. Post-op adverse events were coded in 75% of the cases (16/20 cervical & 5/8 lumbar). The accuracy was better for lumbar as compared to cervical spinal surgeries.

Conclusion: Coding is a universal language of communication and its accuracy is important not just for PbR, but for data quality, audit and research purposes too. The financial implications regarding PbR governed by HRG codes (dictated by OPCS 4.4 & ICD–10 codes) are discussed. Following this study, a clinical coding facilitation form has been introduced to improve data quality.

Ethics approval: None

Interest statement: None

Introduction: Intra-operative localisation of small nidus in osteoid osteoma & osteoblastoma is difficult resulting in failed excision. Wide resection is fraught with prolonged operative time, increased bleeding and instability.

Methods: 8 patients (6M & 2F) with a diagnosis of osteoid osteoma(7) and osteoblastom(1) were operated at our centre between 1995–2005. The mean age at presentation was 20.9 years (9–31 yrs). The tumour was localised to cervical(2), thoracic(4) and lumbar(2) posterior elements respectively. All had back/neck pain of varying duration (mean 20 mo; range 6–48 mo). 2 patients presented with thoraco-lumbar scoliosis and 3 had failed treatments. All patients were worked-up with x-rays, CT/MRI and 99m technetium scan to localise lesion. 600 MBq Tech HMDP(hydroxy-methylene-di-phosphate) was administered intra-venously 3 hrs prior to surgery and fluoroscopy was used to confirm anatomical level. A 5 mm cadmium telluride (Cd Te) probe & rate meter were used to scan the area containing lesion and counts per second (cps) recorded. Background count from adjacent area was obtained for comparison purposes. The tumour nidus was then excised & cps from tumour bed and excised specimen recorded.

Results: The mean follow-up was 5.85 years (2–12.33). The mean cps for osteoid osteoma pre-excision was 203.8 (60–515) which fell to 72.5 (10–220) post-excision. The cps reduced from 373 to 40.5 postoperatively for osteoblastoma. Complete excision was recorded every time and all patients reported characteristic disappearance of pre-operative pain. All had discontinued analgesic medication, returned back to normal activities by 3 months and were followed-up at regular intervals for 2 yrs when they filled NDI, ODI & SF-36 questionnaire.

Discussion: Gamma probe guided surgical excision facilitates accurate localisation of lesion, is less invasive warranting minimal bone resection & resultant instability and perhaps most importantly confirmation of complete excision of the tumour nidus consistently every time (esp. failed surgeries).

Introduction: A prospective randomised controlled trial of circumferantial spinal fusion has shown superior clinical outcome when a femoral ring allograft (FRA) is used compared to when a titanium cage (TC) is used. The implant cost of the TC is nearly ten fold that of the FRA. However the additional costs of surgery and related costs also need to be considered to determine if there is a real cost advantage of FRA over TC. We can find no previously reported studies which economically evaluate the TC and the FRA in circumferential lumbar spinal fusion. The aim of this study was to investigate cost-effectiveness of TCs in comparison to FRAs for circumferential lumbar spinal fusion over a two year National Health Service (NHS) perspective using a cost-utility evaluation

Methods: This randomised study had the approval of the local ethical committee and the institutional research and development board (Reference OR059844) prior to its commencement. Eighty-three patients were randomly allocated to receive either the TC or FRA as part of a circumferential lumbar fusion between 1998 and 2002. NHS costs related to the surgery and revision surgery needed during the trial period were monitored and adjusted to the base year (2005/6 pounds sterling). The Short Form-6D (SF-6D) was administered preoperatively and at 6, 12 and 24 months in order to elicit patient utility and subsequently Quality-Adjusted Life Years (QALYs) for the trial period. Return to paid employment was also monitored. Bootstrapped mean differences in discounted costs and benefits were generated in order to explore cost-effectiveness.

Results: Baseline demographic data including age, sex, smoking history, previous surgery history and number of operated levels did not differ between the two groups. A significant cost difference of £1,942 (AUD4,255), (95% CI £849 (AUD1,860) to £3,145 (AUD6,891)) in favour of FRA was found. Mean QALYs per patient over the 24 month trial period were 0.0522 (SD 0.0326) in the TC group and 0.1914 (SD 0.0398) in the FRA group, producing a significant difference of −0.1392 (95% CI 0.2349 to 0.0436). With regard to employment, incremental productivity costs were estimated at £185,171 (AUD 405,745) in favour of FRA.

Discussion: From an NHS perspective, the trial data show that TC is not cost-effective in circumferential lumbar fusion. The use of FRA was found to dominate (generating greater QALY gains and less cost). In addition FRA patients reported a greater return to work rate and hence, productivity costs were also in favour of FRA.

Introduction: Historically segmental sublaminar wiring (SLW) fixation has been used for the correction of spinal deformity in neuromuscular scoliosis, however pedicle screw (PS) fixation is gaining popularity. We compared the results of both techniques in patients with Duchenne Muscular Dystrophy (DMD).

Methods: Two groups of patients with DMD were matched according to the age at surgery, magnitude of deformity and vital capacity. Indications for surgery included loss of sitting balance, rapid decline of vital capacity and curve progression. In Group 1 (22 patients) SLW fixation was used from T2 to S1 with the Galveston technique. In Group 2 (18 patients) PS fixation was used from T2 to L5. Minimum follow-up was 2 years (range 2–13 years). Radiographs, SRS-22 and lung function tests were performed at standardised intervals.

Results: Mean Cobb angle in Group 1 improved from 47° (range 26°–75°) to 23.5° (range10°–36°) and mean pelvic obliquity improved from 15° (range8°–25°) to 2.4° (range0°–8°). Mean Cobb angle in Group 2 improved from 46° (range28°–82°) to 8.5° (range 0°–18°) and mean pelvic obliquity improved from 15° (range7°–30°) to 1.1° (range 0°–6°) [p< 0.05]. Mean operating time and blood loss were less in Group 2 [p< 0.05]. In Group 1, the infection rate and instrumentation failure was higher, and SRS-22 outcomes showed no significant difference between the groups. Interestingly the mean Body Mass Index (BMI) in Group 2 was much higher than group 1.

Conclusions: PS fixation resulted in superior correction and controlled pelvic obliquity to a large extent without the need for pelvic fixation. Lower rates of infection and failure of instrumentation were noted with PS fixation, despite high BMI of patients presumably due to steroid therapy. We recommend the use of PS instrumentation for the correction of spinal deformity in DMD.

Observation of sub-clinical neurological abnormalities has led to the proposal of a neuro-developmental etiologic model for AIS. Our research group have demonstrated longer latency in somatosensory–evoked potential (SSEP) and impaired balance control in AIS subjects. A previous pilot study compared the regional brain volume between right thoracic AIS subjects and normal controls. Significant regional brain differences were found relating to corpus callosum, premotor cortex, proprioceptive and visual centers. Most of these regions involved the brain unilaterally, indicating there might be abnormal asymmetrical development in the brain in right thoracic AIS. In this pilot study, we investigated whether similar changes are present in left thoracic AIS patients who differ from matched control subjects. Nine AIS female patients with atypical left thoracic AIS (mean age 14.8, mean Cobb angle 19°) and 11 matched controls as well as 20 right thoracic AIS (mean Cobb angle 33.8°) and 17 matched controls, underwent three-dimensional isotropic magnetization prepared rapid acquisition gradient echo (3D_MPRAGE) magnetic resonance (MR) imaging of the brain. Fully automatic morphometric analysis was used to analyse the MR images; it included brain-tissue classification into grey matter (GM), white matter (WM) and cerebrospinal fluid (CSF). and non-linear registration to a template brain. Tissue densities were compared between AIS subjects and controls. There was no significant difference between AIS subjects and normal controls when comparing absolute and relative (i.e. brain-size adjusted) volumes of grey and white matter. Using voxel-based morphometry, significant group differences (controls > left AIS) were found in the density of WM in the genu of the corpus callosum, the left internal capsule (anterior arm) and WM underlying the orbitofrontal cortex of the left hemisphere. The above differences were not observed in the right AIS group. This first controlled study of regional tissue density showed that corpus callosum, which is the major commissural fiber tract, was different in the atypical left thoracic scoliosis while significant regional brain changes have not yet been found in those with typical right thoracic scoliosis. Further investigation is warranted to see whether the above discrepancy is related to laterality of the scoliotic curves and infratentorial neuroanatomical abnormalities. A larger sample and a longitudinal study is required to establish whether the brain abnormalities are predictive of curve progression.

Introduction: Ronald McRae’s textbook clinical orthopaedic examination mentions “Capasso’s method1 of evaluation of coronal plane deformity to be the most sensitive tool of measuring cobb angle. However there is no study to date evaluating/comparing this method against popular & widely used tools viz. cobbometer and traditional protractor.

Objectives: To evaluate Capasso’s method against commonly used measurement aids w.r.t measurement of cobb angle in scoliosis.

Summary of background data: Studies of Cobb method of measurement have multiple sources of error and intra & inter-observer variability. The Capasso’s method which is based on “bi-uni-vocal principle” views the scoliosis curve to be an arc of circumference and to be a true reflection of angular values and hence geometrically more valid.

Methods: 24 scoliosis curves were measured by three different examiners on three separate occasions one week apart by 1) Capasso’s method 2) Cobbometer and 3) Traditional protractor on same set of hard copies of digital x-rays. The three set of Cobb angle readings obtained were statistically analysed for intra & inter-observer reliability and assessed for agreement between the three methods of clinical measurement.

Results: The mean intra observer variability for protractor, cobbometer & Capasso’s methods were 8.50, 5.50 10.00 respectively. The cobb angle readings obtained by Capas-so’s method was higher than the other two methods for all magnitudes of the curves (< 300, 300–600 & > 600) and was more than two times the conventional readings for curves < 300. The disagreement between Capasso’s method with either of the other two methods (cobbometer & protractor) was statistically significant (p< 0.01).

Discussion: This study demonstrates that Capasso’s method significantly overestimates the magnitude of scoliotic deformity esp. for curves < 300 as compared to other existing popular measurement tools. Surgical decision making if were to be based on it would invite criticism and wrath. The present existing methods have their own limitations and the need of the day is a simple three dimensional measuring system to accurately define the magnitude of the deformity.

Introduction: Accurate and ethical coding is challenging and directly impacts on Payment by Results (PbR). The aims & objectives of this study were to review the existing pattern of coding for spinal surgery and ascertain its appropriateness & accuracy for surgical procedures, medical co-morbidities and post-op complications.

Methods: A retrospective review of 70 consecutive cervical and 100 consecutive lumbar spine patients who were operated from April 2006 onwards was conducted. The excel sheet provided by coding department, hospital notes – clinic letters, physicians’ entries, theatre notes and laboratory reports (biochemistry/microbiology/histology) – were reviewed. Of the 170 cases, 165 were available for analysis.

Results: Coding data of 5 patients who underwent cervical spine surgeries were not available. Of the 165 cases, the accuracy of primary procedural codes was 93.9% (90.8% cervical & 96% lumbar). However this reduced to 77.6% (75.4% cervical & 79% lumbar) when the accuracy for entire description of performed surgery was considered. The procedural codes did not specifically reflect the surgery performed and lacked reproducibility. Surgical levels were coded incorrectly in 9% of the cases. Cervical surgeries were coded as lumbar in 4 and posterior surgery as anterior in 3 cases respectively. Harvest of iliac crest bone graft was not coded in 5 cases. Medical comorbidities were coded appropriately in 64.2% of the patients (55% cervical & 70% lumbar). The commonly missed comorbidities were drug allergies, hypercholesterolemia, smoking and alcoholism. Post-op adverse events were coded in 75% of the cases (16/20 cervical & 5/8 lumbar). The accuracy was better for lumbar as compared to cervical spinal surgeries.

Conclusion: Coding is a universal language of communication amongst healthcare professionals. Its accuracy is important not just for PbR, but for data quality, audit and research purposes too. The financial implications regarding PbR governed by HRG codes (dictated by OPCS 4.4 & ICD–10 codes) are discussed. The awareness of clinical coding is low amongst junior doctors. Following this study, a clinical coding facilitation form has been introduced to improve data quality. Our plan is to close the audit loop and re-evaluate. Literature emphasises qualification of coders, legible documentation by physicians and interaction between coders and clinicians.

Introduction: Observation of sub-clinical neurological abnormalities has led to the proposal of a neuro-developmental etiologic model for adolescent idiopathic scoliosis (AIS). We have previously demonstrated prolonged latency in somatosensory evoked potentials (SSEP) and impaired balance control in subjects with AIS. Furthermore we have compared regional brain volumes in right thoracic AIS subjects and normal controls. Significant neuro-anatomic regional differences were observed in the corpus callosum, premotor cortex, proprioceptive and visual centers of the AIS subjects compared to control subjects. Most of these regional differences involved the brain unilaterally, indicating there may be abnormal asymmetrical development in the brain of subjects with right thoracic AIS.

Methods: Following ethical committee approval a total of 29 subjects with AIS were recruited. Patients with congenital, neuromuscular or syndromic scoliosis were excluded from the study. Twenty-eight age- and sex-matched controls were recruited from local schools. All recruits underwent three-dimensional isotropic magnetization prepared rapid acquisition gradient echo (3D_MPRAGE) magnetic resonance (MR) imaging of the brain. Modern morphometric analyses of the MR images were carried out including classification of tissue into grey matter (GM), white matter (WM) and cerebrospinal fluid (CSF). Tissue densities were compared between AIS subjects and controls. Comparisons were made between those subjects with left thoracic AIS (n=9) and age and sex-matched controls (n=11) and those subjects with right thoracic AIS (n=20) and age and sex-matched controls (n=17).

Results: For subjects with left thoracic curves the mean Cobb angle was 19 degrees. For subjects with right thoracic curves the mean Cobb angle was 33.8 degrees There was no significant differences observed between AIS subjects and normal controls when comparing both absolute and relative (i.e. adjusted for brain size) volumes of GM and WM. However voxel-based morphometric analysis identified significant differences in the density of WM in the genu of the corpus callosum, the left internal capsule and WM underlying the left orbitofrontal cortex when comparing those subjects with left thoracic scoliosis to controls. The above differences were not not observed when those subjects with right thoracic scoliosis were compared to controls..

Discussion: This controlled study of regional brain tissue density has demonstrated important differences in the corpus callosum, the left internal capsule and the left orbitofrontal cortex when the brain of those subjects with left thoracic scoliosis is compared to age and sex matched controls. In this study significant regional brain differences have not been identified in those subjects with right thoracic scoliosis. Further studies are warranted to ascertain whether these morphologial differences in the brain are linked with the etiopathogenisis of left sided thoracic scoliosis. A larger sample and a longitudinal study are required to establish whether brain abnormalities are predictive of curve progression.