| Discectomy is the common method of treating lumbar intervertebral disc. herniation clinically. Although these technologies produce a relatively good short-term clinical result in relieving pain, the long-term effect is still unsatisfactory. Many scholars have studied the relation of the discectomy and spinal kinematics or stability through imaging or biomechanical methods, opinions are still not coincidence. Compression of a spinal nerve root within an intervertebral foramen has been demonstrated in patients who have sciatica in clinic. Hasegawa et al, in cadaveric study, showed that significant nerve root compression was commonly associated with a foraminal height of 15 mm or less and a posterior disc height of 4 mm or less. The loosen of intervertebral height after discectomy is the major cause of facet joint overloading, facet joint degeneration compensatively and bucking of ligamentum flavum which result in intervertebral foramen stenosis. Thereby continuous back pain or recurrent of symptoms would occurred postoperative.To date, the studies on morphologic changes of intervertebral foramina after discectomy are few. It doesnt seem to have much meaning that measuring the foramen in pure neutrality posture, because the spine is in dynamic condition. There is no study focused on changes in intervertebral foramina size in the lumbar spine after discectomy.Investigation on biomechanism of discectomy is important to therapeutics instruction clinically. It's the best way to proceed functional reestablishment after discectomy because the intervertebral disc has important biomechanical characteristics. For this purpose, artificial disc replacement (ADR) is designed and used for clinical application as one method of treating lumbar intervertebral disc herniation. ADR can restore intervertebral height, intervertebral foramen, normal physical curvature, mobility, and biomechanics property of lumbar vertebrae. Few studies showed biomechanics characteristics after ADR had no significant difference compared with normal lumbar segment. Up to now, ADR is still in the primary stage of laboratory and clinical application. The reports on clinical outcomes and appropriate indications for the use of ADR are not enough. It is extremely important to study on biomechanics and clinical fields of ADR for prosthesis reform and clinical spreading.Biomechanical approach and Q -shape migration sensor were adopted in our study, foraminal dimensions at L4/5 including height, maximum width and minimum width were measured which applied with load of neutrality and pure moments of flexion, extension and lateral bending, in order to reveal the correlation between discectomy and foraminal morphologic changes, and discuss the anatomic mechanisms of foraminal stenosis in symptoms remain after discectomy procedure. Inaddition, we analyzed the mechanisms of morphologic changes of foramen after ADR in order to provide direct evidence for clinical treatment. Moreover, we performed ADR in the treatment of 22 patients who had lumbar disc herniation, and evaluated their clinical outcomes.Part one: Morphometric and biomechanical analysis of the intervertebral foramina associated with movement of artificial disc replacementObjective: To reveal the correlation between discectomy and foraminal morphologic changes, discuss the anatomic mechanisms of foraminal stenosis in symptoms remaining and pathological changes after discectomy procedure, and interpret the mechanisms of foraminal morphologic changes after artificial disc replacement in order to provide direct evidence for clinical treatment.Method: There were seven motion segments obtained from human cadaveric lumbar spines. Foraminal dimensions at L4/5 including height, maximum width and minimum width were measured with electric biomechanical testing. Specimens were divided into integrity group, discectomy group and ADR group. Each group was applied with load (2000N) of neutrality and pure moments (lONm) of flexion, extensionand lateral bending. Paired-Samples T Test was used...
|
PDF Full Text Request