Abstract
Introduction
Interspinous stabilization has limited indications especially at L5-S1 level. But there's no description of level anatomy of L5-S1 hopeful for DIAM (Medtronic, Memphis, TN, USA) insertion in the literature.
Materials and Methods
We have suggested that short number of CT parameters could be used to check if level anatomy satisfied the requirements of good interspinous stabilization. The parameters are as follows: sagittal size of the spinous process “working part” (from yellow ligament to curved part)>13 mm, it's width from 4 to7 mm, sagittal translation of the vertebra ≤4 mm, segmental angle from 5 to 20°, interspinous height ≤14 mm, density of spinous process (Hounsfield) >200 units, height of the disk>50% (compared to the upper one), S1 spinous process slope (angle among S1 endplate line and upper edge of it's spinous process)<35°. We performed retrospective study among patients operated on L5-S1 level with DIAM device according to offered parameters (Group A - 52 patients 24 men, 28 women, mean age 39,4 ± 9,1) and group of patients, treated with decompressive operation at L5-S1 alone (Group B - 52 patients 19 men, 33 women, mean age 42.7 ± 10.1). Indication for surgery were: disсal herniations, segmental hypermobility, and lateral recess stenosis. Symptoms of leg and back pain and fail of the conservative treatment for 4 weeks were also necessary. Decompressive operations were: microdiscectomy, laminotomy, and medial facet resection. We have compared close (10 days after surgery) and remote results (24 month after surgery) by visual analog scale of pain, Oswestry disability index, patients satisfaction rate, operation time, and blood loss.
Results
In Group A, no reoperations, no unsatisfactory results, 3 satisfactory results, 49 good and excellent results, no implant failure. In Group B, 2 reoperations (unsatisfactory results), 7 satisfactory results, 43 good and excellent results. Visual analog scale for back pain; before the surgery: Group A-52.13 ± 23.5; Group B-48.09 ± 22.49 (no difference: p = 0.39); 10 days after surgery: Group A-19.8 ± 8.74, Group B-16.2 ± 8.44(difference at p = 0.02); 24 month after surgery: Group A-13.31 ± 10.73, Group B-20.17 ± 12.52 (difference at p = 0.00043). Oswestry index; before the operation: Group A 46.26 ± 15.62, Group B-51.27 ± 22.54 (p = 0.27); 24 month after surgery: Group Я-10.26 ± 7.28, Group B-15.02 ± 10.9 (p = 0.032). Blood loss at Group Я-110.7 ± 35.2 mL, Group B-67.4 ± 15.5 Мл(p = 0.0018). Operative time; Group A-115.5 ± 39.6 minutes, Group B-84.6 ± 26.7 minutes (p < 0.001).
Conclusion
Interspinous dynamic stabilization using DIAM device is useful at L5-S1 level in cases where level anatomy lets you to set the device. CT is a method of choice for preoperative planning of the interspinous stabilization.
Yes
None declared