| Objective:To research the feasibility and the clinical value of transforaminal fenestration approach in treatment of far lateral lumbar disc herniation.Method:â‘ anatomical study:In15lumbar spine specimens taken from cadavers of people,we use the transforaminal fenestration approach at the levels L1/2to L5S1,fully exposing the exiting nerve roots and the posterior lateral aspect of disc space and observing the ligment and bony structure;Before and after the fenestration,we take3D-CT measurements at the operative window and resection range;In153D-CT image taken from15adult people,we also take the same measurement;â‘¡10functional spine units taken from10healthy calf fresh cadeveric specimen were cut in sequence,using improved constant displacenment testing method.The procedure is as follows:I normalâ†'â…¡ unilateral transforaminal fenestrationâ†'â…¢unilateral totally facetectomy.Corresponding changes of physiological range of motion and angular displacement were measured by Instron8874dynamic multidimensional biomechanical fatigue testing machine.We calculated the average stiffness according to corresponding changes of torque and angular displacement and we analyzed if unilateral transforaminal fenestration have a obvious influence in lumbar stability according to the statistical analysis.(3)From December2007to September2011,10patients of far lateral lumbar disc herniation were treated with mobile endospine system(Endo spine, Karl Storz German) by transforaminal fenestration approach,including4men and6women with a mean age of54.3years(36-81years).CT and MRI all revealed foraminal and extraforaminal lumbar disc herniation,including L3/4in2cases, L4/5in4cases, L5S1in4cases.During the operation,we observed the area of exposure and resection.After the operation,all the patients underwent the X-ray and CT scanning for observing the area of exposure and resection.During the follow-up,we evaluated the lumbar stability from the hyperextension and hyperflexion X-ray.Results:â‘ in cadaveric specimens and in vivo3D-CT measurement,we can expose the posterior lateral aspect of disc space by the transforaminal fenestration approach,preserving the continuity of the laminae and inferior articular process;From L1/2to L5S1, the isthmus laminae gradually extends farther laterally and eventually covers the waist of the respective vertebral body, the facet joint gradually overlaps the disc space in an upward and lateral direction, the transverse process gradually moves downward;The resection bony structure gradually broaden and the remaining width of inferior articular process gradually become smaller; From L1/2to L3/4,the operative window is large,allowing the surgeon easy access to nerve root and herniated disc in most cases;From L4/5to L5S1, especially at level L5S1, the operative window progressively becomes smaller,requiring more resection of isthmus laminae and facet joint in order to expose exiting nerve root and posterior lateral aspect of disc space,but also can preserving part of inferior articular process and facet joint and the minimum width of the inferior articular process is about4mm;â‘¡The experimental results show that:a,Unilateral transforaminal fenestration do not have a obvious influence to the stability of anterior flexion and posterior extension (P>0.05);b, Unilateral transforaminal fenestration and unilateral totally facetectomy do not have a obvious influence to the stability in the same side rotation and in the opposite side lateral flexion(P>0.05);c, Unilateral transforaminal fenestration do not have a obvious influence to the stability in the opposite side rotation and in the same side lateral flexion(P>0.05).After the unilateral totally facetectomy,the stability of the same side lateral flexion and the opposite side rotation was obvious damaged (P<0.05).â‘¢The procedure was technically successful in all the patients.There was no complication of nerve injury and transfer to open surgery.The mean operative time was60min(range50-70min)with a mean blood loss of150ml(range50-250ml).CT can demonstrate the fully decompression postoperation and preserving the continuity of laminea and facet joint.All the patients were followed up for a mean of12months(range3-24months).According to Macnab scale,the results were excellent in8cases and good in2cases and all of them did not have a performance of instability.Conclusion:Transforaminal fenestration approach is a safe and effective approach in treatment of far lateral lumbar disc herniation... |
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