Across the study population as a whole, the combination treatment of APLD/Ozone/Epidural produced superior results than caudal epidural alone in all outcome measures and at all follow up periods. It produced significantly better mean McNab scores and significantly larger mean improvements in sciatica at final follow up when compared to the caudal epidural treatment (Table 2). 72% of patients treated with APLD/Ozone/Epidural had a successful outcome at one month’s follow up compared to 62.8% of patients treated with caudal epidural alone (Table 3). There was a greater difference at final follow up where 68% of patients treated with APLD/Ozone/Epidural had a successful outcome compared with 51% of patients treated with caudal epidural (Table 5). Despite these large differences in success rates, neither was statistically significant. The apparent superiority of the APLD/Ozone/Epidural treatment was more pronounced when the percentage of patients with good-excellent outcomes was calculated. At one month follow up 56% of patients treated with APLD/Ozone/Epidural had a good-excellent outcome compared to 30.9% treated with caudal epidural (Table 4) and this difference approached significance (p=0.02). Once again there was a greater difference between the treatments at final follow up where 48% of patients treated with APLD/Ozone/Epidural had a good-excellent outcome compared to just 13% treated with caudal epidural (Table 6). This difference was highly significant.

Overall the data demonstrates that the APLD/Ozone/Epidural treatment has a greater efficacy in the treatment of discogenic sciatica than caudal epidural injection alone. As well as this, the APLD/Ozone/Epidural treatment has a longer duration of action as demonstrated by the larger differences between treatment groups at final follow up when compared to one month follow up.

Within the subgroups, the APLD/Ozone/Epidural treatment had a tendency to produce better results than caudal epidural alone, although this difference did not always reach significance, possibly due to the relatively small numbers. Certain patient subgroups demonstrated excellent responses to APLD/Ozone/Epidural treatment with higher McNab scores and significant differences in other outcome measures compared to the caudal epidural treatment. Subgroups which responded most favourably to the APLD/Ozone/Epidural treatment were:

• Age >50 (final follow up success = 75%, good-excellent 75%)
• Male patients (final follow up success = 72.2%, good-excellent 50%)
• Sciatica>LBP (final follow up success = 70%, good-excellent 45%)
• Symptoms ongoing < 1year (final follow up success = 80%, good-excellent 50%)
• Single level disc disease (final follow up success = 76.6%, good-excellent 58.9% )

All but six of the subgroups had significantly higher percentages of good-excellent outcomes in the APLD/Ozone/Epidural treatment group than the caudal epidural group at final follow up. This includes all the above subgroups as well as patients with contained disc herniation (Table 6).

Conversely certain patient subgroups responded less well to the APLD/Ozone/Epidural treatment, with relatively poor outcome scores and levels of success. The subgroups which responded least well to the combination treatment were:

• Multi level disc disease (final follow up success = 50%, good-excellent = 25%)
• LBP>sciatica (final follow up success = 60%, good-excellent = 0%)
• Non contained disc herniation (final follow up success 66%, good-excellent = 33%)

In these subgroups there was also no difference in final success or good-excellent outcome rates between APLD/Ozone/Epidural and caudal epidural treatments at final follow up (Tables 5 & 6).

This data will aid appropriate patient selection for APLD/Ozone/Epidural treatment in clinical practice and also in the subsequent RCT. Male patients, those with symptoms dominated by sciatica rather than LBP and those with single level contained disc herniation are likely to show the greatest improvement. Patients with symptoms dominated by LBP rather than sciatic and those with multi-level non-contained disc herniation are least likely to respond positively to APLD/Ozone/Epidural treatment.

Complications and side effects for each treatment were mild, rare and transient. No major complications occurring and both treatments appear to be safe. This is in agreement with the literature (REFF)

Strengths and limitations