Short segment fixation with the inclusion of the fractured vertebrae versus long segment fixation for the treatment of thoracolumbar fractures- A randomised control trial

SUMMARY

In the present era where LSF (Long segment fixation) is practised, this RCT was planned to SSFIFL (short segment fixation with the inclusion of the fractured level) is superior to LSF in terms of clinical and radiological outcome.

SSFIFL is superior to LSF in terms of better mobility at Thoracolumbar junction and less stiffness, less implant fixation hence less cost, less blood loss, less operative time and less length of post-op hospital stay.

This study consisted of 54 patients equally between the 2 groups. Of the 54 patients, 38 were male and 16 were female. 13 patients (24% of the population) were under 30 years of age. Mean age of the study population was 44 years. 17 patients had comorbidities, of which hypertension was most common seen in 5 patients, followed by hypothyroidism and insomnia on medications seen in 2 patients each.

Most common mode of injury was Fall from height in both the groups, followed by RTA. Most common fractured site overall was D12 and L1 with 20 patients each. However most common fractured site in LSF group was D11 vertebra.   Bowel and Bladder involvement was seen in 28 patients (51.9% of the study population).

Patient was planned for surgery based on the standard and accepted TLICS Score. Most common TLICS Score observed was 6 seen in 20 patients overall (37% of population). However most common TLICS Score in LSF group was 5 seen in 10 patients (18.5 % of population). 5 was the least TLICS Score and 9 was the highest TLICS Score. TLICS score 9 was seen in only 1 patient. Mean TLICS score was found to be 6.43. From the data it was clear that the incidence of bowel and bladder involvement increased as the TLICS Score increased with 100% involvement seen with TLICS score 9, followed by 83.3% involvement with score 8 and 80% involvement seen with score 8. This data was found to be statistically significant.

Clinical assessment was done using ASIA Scale and MRC grading. Improvement was using radiological parameters i.e LKA, ABH, PBH and also from clinical assessment already mentioned. Improvement is suggested by decrease in LKA and increase in ABH and PBH and increase in MRC grading from 0 to 5 and ASIA Scale from A to E.

Out of the 54 patients in the study population, totally 23 patients were of ASIA scale A (10 in LSF, 13 in SSFIFL) and 4 patients of ASIA scale E (3 in LSF and 1 in SSFIFL) in pre-op period. At end of follow up period i.e 6 months postop none were present in ASIA scale A and 13 patients were in ASIA scale E (8 in LSF and 5 in SSFIFL). Thus neurological improvement was seen both groups under the study.

 Our study has shown that the mean Duration of surgery in LSF group is 199.26 minutes and 187.04 minutes in SSF group.

Mean Blood loss is 405.19 ml in LSF group and 310ml in SSFIFL group.

Mean Duration of hospital stay (post-op) is 13.44 days in LSF group and 10.63 days in SSF group. Thus duration of surgery, intra-op  blood loss and post-op length of hospital stay are higher in LSF than SSF

4 patients had dural injury, 2 each in LSF and SSFIFL groups. Postop 2 of them had drain in situ for prolonged duration because of CSF leak. 3 patients in LSF group had got wound infected, hence some stitches were opened to let out the collection, followed by secondary suturing. 3 patients in LSF and 2 patients in SSFIFL group had wound discharge requiring repeated stitches lengthening post-op hospital stay. No implant failure noted in any of the groups. Thus overall complication rate was higher in LSF than SSF.

Mean preop LKA was 20.49 in LSF group and 21.26 in SSFIFL group which decreased to 8.43 in LSF group and 9.27 in SSFIFL group in the immediate post-op period. At the end of final follow up i.e 6 months post-op mean decrease in LKA achieved was 13.89 in LSF and 14.2 in SSFIFL group.

 Mean ABH and mean PBH were 12.43 and 17.33 respectively in LSF group and 9.6 and 14.24 respectively in SSFIFL group which increased to 16.01 and 20.71 in the LSF group and 13.2 and 18.02 in the SSFIFL groups respectively in the immediate post-op period. And at the end of final follow up i.e 6 months post-op mean increase in ABH and PBH were respectively 5.3 and 5.23 in LSF group and 6 and 5.7 in SSFIFL group.

In our study 4 patients, 2 in each group had loss of kyphosis correction with concurrent loss of anterior body height. However these 2 patients in SSF group were the ones who had screw inserted into only one pedicle of the fractured vertebra as the other pedicle was fractured. A further study is warranted entailing the details of type of implant used, levels of laminectomy performed, surgical accuracy in screw insertion, multiple attempts at screw insertion.

 ABH and PBH restoration is attributed to many reasons. The lordotically contoured rods and pedicle screw fixation at the fractured vertebra can produce a forward driving force to enhance the reduction and reshaping. Moreover, the screw inserted into the fractured vertebra can be used to directly raise the end plate to assist in the restoration of the compressed vertebral height. Second, short-segment fixation with intermediate screws can improve the stress distribution of the internal fixation system and protect the uninjured vertebra and intervertebral disc. Finally, there may be a vertebral body filling effect because vertebral compression results in trabecular bone destruction; a cavity is produced within the vertebral body after reduction. This may induce vertebral recollapse postoperatively. A pedicle screw inserted into the fractured vertebra can fill this cavity, resulting in a better reduction of the fractured vertebra. Hence SSF is superior than LSF in our analysis.

  From this data its clear that the LKA, ABH, PBH in both LSF and SSFIFL groups at the end of follow up are almost same or comparable making it clear that almost same amount of improvement can be achieved with SSFIFL at the cost of less level of implant fixation, less implant cost, less blood loss, less operative time, less post-op hospital stay as compared to LSF group.