Oral Posters: MIS
Presented by: V. Gupte - View Audio/Video Presentation (Members Only)
(1) Fortis Hospitals Mulund, Spine Surgery, Mumbai, India
Object: Assessment of effects of three different surgical approaches for spinal decompression in degenerative lumbar canal stenosis involving single to multiple level with no instability.
Method: A total of 50 patients with lumbar canal stenosis were divided on the basis of choice of surgical technique into 3 groups : MLD (17 patient's with 2-3 level stenosis), MED-UBF through Metrx Tubular System (17 patient's with 1 and 2 level stenosis) & SPS-multilevel (16 patient's with 2 level, 3 level and 4 level stenosis).Out of 50 patient's, 15 patient's had medical co-morbidities. Clinical & functional outcome assessment was performed by giving ODI questionnaire to all patients at pre-op, 6 weeks, 3 months, 6 months ; & VAS was recorded at preop, at the time of discharge, 6 weeks, 3 months, 6 months.Paraspinal muscle damage was assessed with biochemical markers CPK-MB, CRP which were measured preop and postoperatively at day 2. MRI changes in the paravertebral musculature were evaluated at 3 month follow-up. Other parameters such as blood loss, operative time, length of hospital stay were used to judge learning-curve of minimal invasive techniques.
Results: All patient's showed appreciable clinical and functional recovery between 6 weeks to 3 months post-operatively with improved activities of daily living; although statistically there is no difference in VAS & ODI (p > 0.05) from preop to follow-up 6 months in all the three techniques (MED-UBF , MLD, SPS). Post-operatively none of the patient's had wound infection, and biochemical markers CPK-MB & CRP (p>0.05) did not show significant differences in their values in all the three techniques. There is no significant difference between blood losses (p>0.05). Post-operative MRI axial T-2 weighted cross-sectional area measurement & evaluation at L4-5 level at 3 months showed little muscle atrophy with fat infiltration in multifidus muscle in MLD 2-3 levels; whereas normal muscle configuration seen in MED-UBF and SPS showed no atrophy but very minimal fatty infiltration of multifidus with a wide canal with intact spinous process. There is significant statistical difference in operative time and hospital stay(p< 0.05) which decreased with experience and thereby overcoming the learning-curve involved in minimal invasive techniques.
Conclusion: Minimal invasive lumbar spinal decompression techniques preserved the posterior elements esp. spinous processes and also the multifidus muscle which is the main stabilizer. With good experience, these minimal invasive techniques can be performed as efficiently and quickly as the conventional laminectomy. A surgeon not accustomed to microscope can perform SPS for its similar exposure like the conventional laminectomy. In our experience with minimal invasive approaches, patient's especially with medical co-morbidities showed early mobilisation and required lesser hospitalization stay, so probably MISS has an edge over conventional laminectomy in stable degenerative lumbar canal stenosis.