Study Design

Prospective cohort study.

Purpose: To determine presentation to publication conversion rate(PPCR) in peer-reviewed indexed journals of abstracts presented at SRS annual meetings and to evaluate for consistency between abstracts and subsequently published full-text articles(FTA).

Methods: We reviewed all presentations (podium & posters) of past SRS annual meeting proceedings(2000–04) and undertook a comprehensive PubMed search to determine if the abstract was followed by a publication subsequent to its presentation as FTA up to Dec 2008. The published FTA was compared with original abstract(OAb) and evaluated for consistency with respect to study cohort/design, conclusion and authorship against a structured proforma.

Results: 1063 abstracts(452 podium;611 posters) were identified. 560 (295 podium;265 posters) were published as FTA in 51 journals. The overall PPCR was 52.68%(65.26 for podium;43.37% for posters). Two-thirds of them were published in Spine (361 FTA). 87.32% of them were published within 3 years of presentation(489/560). Interestingly 16 presentations were already published as FTA before their sub-mission(2.85%). The PPCR was 1.5 times higher for free-papers as compared to posters and was statistically significant (p< 0.0001) and OR 2.45(1.90–3.15).

Conclusion: The PPCR of SRS presentations is better than AAOS(34.2%;Bhandari et al, JBJS(Am)2002:84(4),615–21) and stands high in comparison to other medical specialties (32–72%). Though the studies were of high quality/content, changes to the cohort, authors or/& conclusion was common (seen in two-thirds of FTA). The acceptance of an abstract for podium presentation at SRS annual meeting is a benchmark of quality. However they (esp. posters) should be interpreted with caution until their subsequent publication as a FTA.

Ethics approval: Not applicable

Interest Statement: None (No grants obtained from any agency).

Purpose: There is no consensus regarding indications for anterior release and causative factors of junction kyphosis(JK) in Scheuermann’s Kyphosis(SK).

Methods: A retrospective review of 35 patients(19♂; 16♀) who underwent surgery for SK with a minimum follow-up of 5 years was undertaken. The mean age & follow-up were 20.5(13.25–45.75y) and 9 years(5–22y) respectively. Patient demographics, clinicoradiological parameters & functional outcomes (ODI/SRS-22) were assessed. The incidence of JK was correlated with radiographic parameters & instrumentation levels. Outcomes of posterior instrumentation(GroupI-13) were compared with anterior release & posterior instrumentation(GroupII-22).

Results: Cobb Λle of ≥600 hyperextension radiographs and presence of anterior bony bridge required anterior release. JK(≥100) was seen in 12 cases (7 proximal & 5 distal). PJK was seen in cases where T3-4 was the upper instrumented vertebra(UIV). DJK was seen in patients with body mass index(BMI) of ≥30 and when LIV did not include 1st lordotic disc. There was significant difference in mean thoracic kyphosis(TK) correction between the 2 groups (35.70vs44.50;p=0.003). The mean loss of correction at 9 yrs was 5.90 and 3.40 respectively. 33/35 were subjectively satisfied with cosmesis and 28/35 patients returned to their previous occupation. Three were off work due to chronic back pain and four patients had job modifications.

Conclusion: Stiff curves require anterior release. PJK could be overcome by including T2 as UIV.

DJK could be prevented by including 1st lordotic disc in LIV. Extending lower Instrumentation to L3 would reduce the risk of implant failure in obese patients. There was no advantage of cages over rib grafts.

Ethics approval: Not applicable

Interest Statement: None (No grants obtained from any agency)

Introduction: We have compared the results of pedicle screw (PS) construct only with a hybrid sublaminar wire and pedicle screw construct (HS) in a matched cohort of CP patients, to establish which technique is superior in view of deformity correction and its maintenance.

Methods: 22 male and 14 female CP patients with average age of 16 years (range 8–25 years) underwent surgical correction for spinal deformity. Indications for surgery included loss of sitting balance, progression of spinal deformity, pelvic obliquity and back pain. Group 1 (18 patients) had PS construct only and Group 2 (18 patients) had HS constructs. 32 patients (90%) required sacral fixation. 5 patients in Group 2 required anterior release. All patients had a minimum follow-up of 2 years (range 2–13 years). Clinical and radiographic analyses were performed in both groups.

Results: Mean Cobb angle in Group 1 improved from 650 (range 120–950) to 18.50 (range 0–280) and in Group 2 from 77.60 (range 400–1050) to 34.80 (range 100–620) [p < 0.05]. Mean pelvic obliquity in Group 1 improved from 14.30 (range 00–420) to 2.50 (range 00–50) and in Group 2 from 24.70 (100–510) to 9.70 (range 20–180) [p< 0.05]. Mean surgical time in Group 1 was 224 minutes as compared to 260 minutes in Group 2 [P< 0.05]. 6 patients in Group 2 had proximal junctional kyphosis and implant failure requiring revision. One patient in each group had infection treated with antibiotic therapy.

Conclusions: PS fixation in CP patients, allowed significant correction of large curves without anterior release, eliminated proximal junctional kyphosis and instrumentation failure. Correction of pelvic obliquity was also superior due to three-dimensional corrective force of pedicle screws. Although PS fixation is expensive and technically demanding, it outweighs the costs incurred by two-stage surgery because of its superior durability correction.

Introduction: Correction of lumbar spine deformity in ankylosing spondylitis (AS) can be achieved by pedicle subtraction osteotomy (PSO), polysegmental osteotomy (PO) or Smith-Petersen osteotomy (SPO). We report our results with these three techniques.

Methods: 26 males and 5 females with AS and average age of 54.7 years (range 40–74 years) underwent surgery for loss of sagittal balance, horizontal gaze and back pain. 12 patients underwent PSO, 10 SPO, and 9 PO. Osteotomy was carried out at L3 in PSO and SPO with pedicle fixation from T11 to S1. 9 patients with PO had osteotomy from L2–5 and fixation from T10-S1. Sagittal translation during corrective manoeuvre was controlled in 21 patients by application of temporary malleable rods, which were substituted with permanent rods. TLSO was used post-operatively for average period of three months. Mean follow-up was 4.2 years (range 1–9 years). Radiographic and clinical outcomes (ODI, VAS, SRS-22) were analysed.

Results: Mean kyphotic correction in PSO was 380 (range 250–490), in PO was 300 (range 280–400) and in SPO was 280 (range 240–380). The sacrohorizontal angle improved by 190(range 50–300) in PSO, 210 (range 80–280) in PO and 150 (range 50–180) in SPO. Outcome scores were better in PSO and PO as compared to SPO. Blood loss and transient nerve root palsy was slightly higher in PSO group. One patient with SPO had fatal bleeding as a result of aortic injury.

Conclusions: Regular use of temporary malleable rods is recommended to prevent sagittal translation during correction reducing the risk of neurological injury. Better correction of deformity was achieved with PSO and PO at the expense of increased blood loss. SPO can increase the risk of vascular injury, therefore we recommend PSO and PO for correction of deformity in Ankylosing Spondylitis.

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.

Introduction: The literature regarding the functional outcome following C1–C2 surgeries for non-rheumatoid C1–C2 pathologies following selective arthrodesis is sparse.

Aim: To determine the long term correlation between functional outcome and radiological determinants following C1–C2 fusion for conditions other than RA.

Methods: All C1–C2 surgeris performed between 1988–2002 for non-RA etiologies were reviewed retrospectively. Selective C1–C2 fusion performed in 32 pts with a min f/u of 5 yrs formed the study group. The mean age at surgery was 57.2 yrs (r 22–84yrs). The etiologies were trauma (15), non-union (6), congenital AAD (2), C1–C2 deg. arthropathy (2), os odontoideum (2), tumours (4) and instability due to TB (1). Neurodeficit were present in 7 pts. Transarticular (TA) screws supplemented with posterior wiring was performed in 27 & posterior wiring alone in 5 pts respectively. A monocortical H-shaped autograft from iliac crest was used in all cases. There were two deaths & two pts were lost for F/U. The mean F/U was 7.8 yrs (r 5–13 yrs). Disability & pain using NDI & VAS and subjective satisfaction were recorded in all pts. We measured 1) C1/2 fixation angle, 2) Inclination of C1, 3) Anterior shift of C2 and 4) C2–7 lordosis on pre and final F/U lateral x-rays.

Results: Optimal TA screw placement was seen in 78.5% of pts. The mean improvement in NDI & VAS were from 55.4% to 19.6% and 8.4 to 1.6 respectively and was better in younger pts. Fusion was seen radiologically in 82.1% of pts at 12 mo post surgery. Segmental stability and resolution of symptoms was seen in all patients despite implant failure in 4 and incomplete fusion 5 cases respectively. Two wound dehiscences needed debridement of which one elderly pt died of MRSA sepsis 2 mo post-op. The C1–C2 segmental lordosis was significantly increased by surgery (−4.2 0 vs. −11.80; P=0.016). The subaxial cervical spine became less lordotic in initial few months post-op but eventually regained more lordosis as time progressed. The C1 inclination came into more extended position w.r.t horizontal line post-op with minimal loss of inclination subsequently. C1–C2 fixation angle and anterior shift of C2 did not have significant correlation with long term functional outcome i.e. NDI and VAS (r=0.35, p=0.17).

Conclusion: The functional outcome following C1–C2 arthrodesis is usually good despite metalwork issues and incomplete fusion in these selective group of non-rheumatoid arthritis pathologies.

Aim: Retrospective review of patients after coccygectomy for post traumatic coccydynia.

Methods: 13 patients (2 male, 11 female; mean age 37.8 years) who had undergone coccygectomy in our unit between 1995–2005 were identified and their case notes were reviewed. All patients had coccydynia with clear history of trauma, had failed to respond to three MUA and injections, and on clinical examination by senior author had hypermobile coccyx.

All patients were operated by the senior author, using a standard technique whereby all segments of the coccyx from sacrococcygeal joint were excised. At follow up postal questionnaire was sent to all patients. This included, Visual Analogue Score (VAS) for Pain now and VAS for pain over one week, overall patient satisfaction, and Oswestry disability Index (ODI), The non-respondents were contacted by telephone 3 weeks later. Overall response was 100%.

RESULTS: Mean time from the onset of symptoms to coccygectomy was 23.8 months (range 5–72). Average length of follow up was 3.8 years (range 0.7–10.8).

6 patients (46%) had 0 pain for VAS now and VAS over one week. 2 patients (15%) had mild pain VAS (1,2) for pain now and over 1 week, and 4 patients(31%) had moderate pain VAS (5,5,5,6) for pain now and VAS (5,5,5,5) for pain over 1 week and 1 patient (8%) had severe pain VAS (8).

ODI was normal or mild disability (0–20%) in 8 patients (71%), 4 patients had moderate disability (ODI 21–40%) and 1 had sever disability (ODI 54%).

Overall Ten patients (76.9%) were satisfied with the result and would consider the same surgery again.

Conclusion: Surgical treatment of post traumatic coccydynia resistant to conservative measures can lead to satisfactory results, if appropriate patient selection criteria are applied.

Background: To analyse the effects of surgery on sagittal alignment¹ in patients with severe Scheuermann’s kyphosis. To assess the ability of two surgical techniques to prevent loss of correction in the thoracic kyphosis. To assess factors of patient’s Body Mass Index (BMI) and instrumentation level on the risk of adjacent level kyphosis or pullout.

Methods: A retrospective study of 13 consecutive cases of rigid Scheuermann’s kyphosis. Group A: 6 patients with anterior interbody cages. GroupB: 7 patients with interbody autogenous rib graft. All patients were instrumented posteriorly from T2 to L2. Radiographs from initial presentation, pre-operatively, post-operatively and at final follow –up were assessed. The thoracic kyphosis, lumbar lordosis, sagittal balance² and sacral inclination were measured.

Results: There were 7 males and 6 females with a mean age of 22 years (range 15 to 38yrs). The mean follow-up was 26 months (range 7 to 53 mths). In Group A: the mean preoperative kyphosis was 87° (range 82° to 92° ) and postoperative kyphosis was 45° (range 38° to 60°). The mean loss of correction was 0.3° (range 0° to2°). In Group B: the mean preoperative kyphosis was 83° (range 70° to 100°) while the postoperative kyphosis was 43° (range 30° to 60°). The mean loss of correction was 1.1° (range 0°to 2°) at final follow-up. The mean lumbar lordosis pre-operatively for all patients was 66° (range 62° to 84°) reducing to 48° (range 34° to 82°) following surgery. The mean sacral inclination pre-operatively was 41° (range 18° to 80°) reducing to 32 °(range 14°to 40°) following surgery. The mean sagittal balance preoperatively was −1.1 cm (range +0.1 to −3.5). It reduced postoperatively to −2.2 cm (range +1.5 to −4 cm) and was −1.6cm (range +0.2 to – 3.5cm) at final follow- up. Three patients with BMI greater than 25 had an increased lumbar lordosis at final follow up, with one case of implant failure and 2 cases with lower junctional kyphosis. No patient had an upper thoracic junctional kyphosis. There was no evidence of neurological compromise.

Conclusion: Patients had a mean thoracic kyphosis correction of 41° (49%). This was maintained during follow-up with no significant difference between autograft and cages. Cranially, all patients had instrumentation to T2 and there was no junctional kyphosis. Caudally, three obese patients (BMI > 25) suffered screw pullout (1 patient) or junctional kyphosis (2 patients). Instrumentation to L3 may avoid this complication in this patient group. The lumbar lordosis and sacral inclination reduced immediately postoperatively, with further correction at final follow –up.

Background: A 9- year-old child with osteogenesis imperfecta and severe cervical kyphosis associated with wedged vertebrae and progressive neurological deterioration is presented. There is no report of upper cervical kyphosis associated with wedged vertebrae in osteogenesis imperfecta in the literature. We discuss the methods and difficulties in the surgical management of this condition and to highlight the appropriate surgical approach.

Methods: Methods:A 9-year-old girl presented with progressive cervical kyphosis and quadriparesis. At the age of 3 years she underwent posterior cervical fusion (C1–C6) for instability and deformity. Radiological and laboratory investigations confirmed the diagnosis of osteogenesis imperfecta. Radiographs of the cervical spine revealed a kyphotic deformity of 120° Magnetic Resonance Imaging (MRI) and Computerised Tomography (CT) scans showed anterior cord compression due to wedged vertebrae at C3 and C4. MRI-Angiography was performed pre-operatively to identify the anatomical position of the vertebral arteries. A modified anterolateral approach to the upper cervical spine was performed. Anterior C3 and C4 corpectomies with interbody fusion with cage and plate fixation was carried out.

Results: Postoperatively the patient made a full neurological recovery and significant correction of the deformity was achieved and correction was maintained at final follow-up.

Conclusion: Cervical kyphotic deformity in Osteogenesis Imperfecta is uncommon. Association of this condition with wedged vertebrae is rare. Surgical decompression of the upper cervical spine with severe kyphosis is a challenging problem. Which surgical approach should be used is controversial? There are difficulties exposing wedged vertebrae by a standard anterior or chin split approach to perform vertebrectomy. Costo-transversectomy has been used successfully in patients with Gibbous deformity in the thoracic spine but due the presence of vertebral artery in the cervical spine posterolateral approach is impossible. We have used a modified anterolateral approach to overcome this problem. Spinal stabilisation in children with Osteogenesis Imperfecta and poor bone quality is another challenge. We have used a small diameter MOSS cage with maxillofacial plate and screws to achieve stabilisation and fusion. The purpose of this report is to highlight the importance of diagnosis of progressive cervical kyphotic deformity in children with osteogenesis imperfecta and also to describe the difficulties encountered with surgical management of this condition.

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 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.

Ongoing debate exists as to the integrity of the abdominal musculature unit in maintaining spinal support and stability. It is thought that the intra-abdominal pressure generated is important in spine stabilisation. Congenital aplasia of the abdominal musculature, i.e. prune belly syndrome (PBS), might therefore result in loss of spinal function and stability. We discuss the possible role of an intact abdominal musculature mechanism in maintaining spinal saggital balance and its relevance to low back pain with this case illustration of PBS. We also review the literature for the incidence of spinal deformities related to PBS.

We present a unique case of a 33-year-old male with PBS that resulted in loss of spinal saggital balance and development of a thoracic hypokyphotic deformity and thoracolumbar scoliosis. The patient also suffered from mild low back pain. Literature review suggests that secondary scoliosis appears to be the most commonly reported spinal deformity with up to 36% of cases being affected in one study.

Unequal compressive forces on the vertebral end-plates as a result of changes in static rib support, dynamic paraspinal muscle support, and changes in intrathoracic and intra-abdominal pressures may be the proposed mechanisms for the spinal deformities. Compensatory lumbar paraspinal over-activity due to the inability to generate normal intra-abdominal pressures because of a deficient abdominal wall musculature mechanism seems to be the plausible explanation for the thoracic hypokyphotic deformity observed. As a corollary, a failing abdominal wall musculature mechanism has been implicated in the risk for low back pain and its sequelae. Our case implicates that an intact abdominal musculature unit might be important in the maintenance of overall spinal function and stability. Maintaining normal intra-abdominal pressures, and the effects of abdominal exercises on this mechanism, i.e. training specificity, remain an important adjunct to our routine treatment of patients with low back pain.

Objective: This study investigates whether the sequence of anterior and posterior procedure has any effect on the lordosis, disc height and stability in combined A-P fusion of the lumbar spine.

Design: A biomechanical study on cadaver lumbar spine.

Materials and Methods: Twelve motion segments (between L2–L5) from four cadaver lumbar spines were studied. Anterior and posterior stabilization were performed using a Syncage (Synthes, Switzerland) of appropriate sizes, and translaminar screws respectively. Load-deformation characteristics in flexion-extension, lateral bending, and torsion were tested in a material-testing machine (Dartec, Stourbridge, UK) with 7.5Nm cyclical load. Angular deformation of each motion segment was determined simultaneously, by 2-D optical reflex camera system (Pro-reflex, Qualysis, Sweden). Disc height, and angle of lordosis between the adjacent endplates were determined from lateral radiographs. These parameters were measured in the intact spine, after A-P fixation with front first, and after back procedure first.

Results: Compared to the intact spine, the disc height was significantly increased (p< 0.05) when Syncages were introduced before posterior fixation, but not when posterior fixation was done first (p = 0.12). The angle of lordosis was increased significantly with posterior stabilization first, but only marginally, with anterior stabilization first. The stability of the motion segments increased significantly with combined A-P fusion, compared to either anterior or posterior fixation alone. With posterior stabilization first, the stability in all directions were greater but not statistically significant, compared to anterior stabilization first (p> 0.05).

Conclusion: In combined A-P fusion of lumbar spine, the lordosis is better restored when posterior stabilization is done first, but disc height is better restored when the anterior stabilization is performed first. Stability of fixation is not significantly affected by altering the sequence.