Introduction: Pedicle screws are now commonly used to instrument the thoracic spine and offers improved three point fixation and therefore theoretically offers better derotation of the spine during corrective manoeuvres in scoliosis surgery.

Aim: To compare thoracic scoliosis correction using either pedicle hooks or pedicle screws.

Methods: Two patient groups were studied. Data was collected prospectively and this is a review of the radiological data. All patients had structural thoracic scoliosis. Group 1, 14 patients (9 female and 5 male) mean age 14.6, were treated with posterior correction of scoliosis using the standard USS II technique using pedicle hooks and screws. Group 2, 14 patients (11 female and 3 male) mean age 15.3 were treated using pedicle screws alone to correct the apical deformity, using a variation of the original USS technique. Pre and postoperative Cobb angle, apical vertebral rotation (AVR, Perdriolle method) and apical vertebral translation (AVT) were measured. Unpaired “t” test was used to compare the magnitude of correction in both groups. The mean follow up period was 30 months (range: 27–42).

Results: The mean corrections of Cobb angle, AVR and AVT, in group I were 61.1% (range: 48.5–83.9), 33.3% (range: 8.6–100) and 62.9% (range: 43.2–91.4), respectively. In Group 2 the corrections were: 57.4% (range: 21.4–81.7), 57.2% (range:16.7–100) and 58.7% (range: 34–80.9). There were no statistically significant differences between the correction of Cobb angle or AVT in both groups (P=0.479 and 0.443 respectively). However, the pedicle screws proved to be more effective at correcting the AVR (P= 0.017). No complications occurred and correction has been well maintained with a minimum of 2 year follow-up.

Conclusion: Pedicle screws can safely and effectively replace the pedicle hooks in the classical USS technique. They are more effective at correcting the rotational deformity, although do not provide a better correction of Cobb angle. These technical results now need to be correlated with relevant clinical outcomes.

Background: Over several decades, investigators have been trying to identify the painful degenerate disc. Their work included two main methods. The first was to set criteria on the radiological investigations, mainly the MRI scan, to describe the severity of the degenerative disc disease (DDD); and the second was to perform discographies. Neither of these two methods precluded the need for the other.

Purpose: Using Pfirrmann’s classification, we correlated static MRI images, for the severity of segmental disc degeneration, with dynamic lumbar discography, with the aim to improve the identification of painful ‘disco-genic’ intervertebral segments.

Study design: Prospective cohort study. Inclusion criteria included patients with mechanical low back pain who exhausted the conservative measures and required surgical treatment.

Patient Sample and Methods: We investigated 69 patients (45 females, 24 males). The average age was 38.9 years (range 20–56). All patients had degenerative disc disease (DDD) on lumbar MRI scans. Provocative discographies were performed in all cases as a routine investigation to identify painful levels prior to fusion or disc replacement surgery. The severity of DDD was graded using Pfirrmann’s classification. A total of 162 discographies were performed using the ‘miss the facet joint, double needle technique’.

Outcome measures: During discography typical or concordant pain only was regarded as positive. Among each of the five Pfirrmann grades, the percentage of positive discographies was calculated. Significance and correlation then were investigated using the Chi-squared and Spearman’s correlation tests.

Results: 24 discs were classified as Pfirrmann grade I, 33 grade II, 63 grade III, 27 grade IV and 15 grade V. The percentages of positive provocative discography for concordant pain among these groups were 0%, 9.1%, 71.4%, 100% and 100% respectively. Statistical analysis showed a high correlation between the severity of DDD on MRI scan and the result of the provocative discography (Chi2 = 32.96, P < 0.001 and correlation coefficient = 0.756).

Conclusion: The higher the grade of segmental DDD, the more likely it will be painful on discography. All discs showing Pfirmann grade IV and V disease were painful on discography. We strongly recommend the Pfirrmann classification for use in grading the severity of lumbar DDD especially when assessing for its association with discogenic pain as determined by provocative discography.

Introduction: The role of discography before lumbar fusion had been discussed in the literature. No study discussed its role before total lumbar disc replacement (TDR). Degenerate discs are not necessarily painful, even if they show Modic changes or HIZ. Moreover, discogenic pain might not be the predominant element in the patient’s symptoms and most of the back pain could be originating form other spinal structures. The aim of our prospective cohort study is to show whether or not provocative discography plays any significant role before TDR and to define that role.

Methods: Twenty patients (11 females and 9 males) had “Prodisc” TDR. Mean age = 38.5 years (range: 20–56). All patients had mechanical low back pain with degenerative disc disease diagnosed by MRI scan. 65% (N=13) had radicular pain as well. The mean duration of back pain = 66.9 months (range: 16–240). Pre-operative provocative discography was performed in all cases. The clinical outcome was assessed by comparing the preoperative SF36-v2, ODI and VAS scores’ means to the 3, 6, 12 and 24 months post-operative ones and also comparing the last follow up SF36-v2 scores with the, age and sex adjusted, normative data for the general UK population obtained from the Oxford Healthy Lifestyle Survey III. All patients were followed up for a minimum of 2 years.

Results: 90% (N=18) experienced a clinically significant improvement of their back pain (MCID for SF36-v2 scales=1SD, ODI=10 points and VAS=2 points). There has been a statistically significant improvement in the follow up outcome measures (P< 0.05) at 3, 6, 12 and 24 mths. SF 36-v2 scores of 15% of patients (N=3) reached or exceeded the normative values for the UK general population.

Conclusion: Provocative discography is an important diagnostic tool before TDR. It is the only dynamic method to diagnose discogenic pain and is indispensable to exclude the painless levels in cases of multilevel disc degeneration.

Aim: To compare thoracic scoliosis correction using either pedicle hooks or pedicle screws.

Methods and results: Two patient groups were studied. Data was collected prospectively and this is a review of the radiological data. All patients had structural thoracic scoliosis. Group 1, 14 patients (9 female and 5 male) mean age 14.6, were treated with posterior correction of scoliosis using the standard USS II technique using pedicle hooks and screws. Group 2, 14 patients (11 female and 3 male) mean age 15.3 were treated using pedicle screws alone to correct the apical deformity, using a variation of the original USS technique. Pre and postoperative Cobb angle, apical vertebral rotation (AVR, Perdriolle method) and apical vertebral translation (AVT) were measured.

Unpaired “t” test was used to compare the magnitude of correction in both groups. The mean follow up period was 6.7 months (range:3–18).

The mean corrections of Cobb angle, AVR and AVT, in group I were 61.1% (range:48.5–83.9), 33.3% (range:8.6–100) and 62.9% (range:43.2–91.4), respectively. In Group 2 the corrections were: 57.4% (range:21.4–81.7), 57.2% (range:16.7–100) and 58.7% (range:34–80.9).

There is no statistically significant difference between the correction of Cobb angle or AVT in both groups (P=0.479 and 0.443 respectively). However, the pedicle screws proved to be more effective at correcting the AVR (P= 0.017). No complications occurred and correction has been well maintained.

Conclusion: Pedicle screws can safely and effectively replace the pedicle hooks in the classical USS technique. They are more effective at correcting the rotational deformity, although do not provide a better correction of Cobb angle. These technical results now need to be correlated with relevant clinical outcomes.