Paradoxical suit in L5-S1 adult spondylolytic …

نوشته شده در موضوع خرید اینترنتی در ۱۳ اردیبهشت ۱۳۹۴

Discussion

In patients with inconstant spondylolysis, spondylolisthesis formula since a pars forsake disconnects a vertebral physique from a defective articular process. The detriment of this posterior stabilising component causes a vertebra to be receptive to extreme brazen interpretation during spinal flexion [8]. This, however, does not explain since enigmatic transformation of a L5/S1 shred occurs. Similarly, other factors that play a purpose in spondylolisthesis such as pelvic incidence, sacral slope, pelvic lean and lumbar lordosis also do not explain this materialisation [9].

The initial box of enigmatic suit was described by Knuttsson [3]. In his study, he analysed radiographic facilities of instability in degenerative front disease. From his conspirator of 140 patients, he beheld that 4 cases had a “displacement in a instruction conflicting to flexion” of a L5 vertebrae. Unfortunately, some-more sum on a patients’ age, form of listhesis or a volume of interpretation were not available.

More recently, Ehara and Shimamura reported a box of enigmatic suit in a 27-year-old masculine with L5/S1 spondylolytic spondylolisthesis [4]. Here, flexion was seen to means an anterolisthesis of 4 mm, since prolongation accentuated this to 8 mm. Schneider et al. [8] achieved a kinematic investigate on a lumbar spine in patients with spondylolytic spondylolisthesis. He used a ICR (instantaneous centre of rotation) to analyse suit differences opposite a influenced segments during flexion and extension. Interestingly, 6 of a 13 patients complicated displayed enigmatic motion, with displacements trimming from 0.5 to 4.5 mm.

In a series, 6 out of 12 patients with instability displayed enigmatic motion. We chose to investigate usually translational suit as this had a larger change on symptoms than angulation [2]. The “nutcracker” speculation explains this observation. During extension, a maiden mainstay is subjected to a distractive force, while a posterior mainstay is subjected to a compressive force. This application causes impingement of a posterior elements which, when joined with a pars defect, displaces a L5 vertebra brazen and accentuates a anterolisthesis (Fig. ۵).

This impingement speculation is not a new concept. Roussouly et al. [9] presumed that a growth of spondylolysis was due to dual variations in a sagittal fixing of a spine. In some individuals, a plane course of a lumbar–sacral connection (low sacral slope) formula in a L5 vertebra being pushed out after impingement by a L4 and sacrum. Conversely, people with a plumb aligned lumbar–sacral connection (high sacral slope) grown spondylolysis from extreme brazen traction on a pars of a L5 vertebra, instead of a nutcracker outcome (Fig. ۶).

In gripping with Roussouly’s aetiology of spondylolysis, we trust that patients from a “impingement” organisation will uncover enigmatic suit during energetic motion—as prolongation will intensify a application of L4 on a sacrum and means brazen banishment of a L5 vertebral body. On a other hand, those with a “traction” form listhesis will uncover displacements identical to a instruction of flexion or extension, as is required belief.

The certain association between a trip angle and enigmatic suit (p  ۰٫۰۰۶) reinforces a speculation of posterior impingement. In these patients, a lordosis during a lumbo–sacral connection is some-more pronounced, and in turn, might outcome in impingement of a L4 spinous routine on a sacrum in a neutral or honest viewpoint (Fig. ۵).

While a statistical analyses do not uncover any poignant association between a sacral slope and enigmatic motion, we trust a supposition is still valid. This is since a dimensions of a sacral slope is contingent on a orientation of a pelvis, i.e., a dimensions varies with posture. For a some-more accurate measurement, a pelvic occurrence should be taken into comment as this reflects a loyal morphology of a pelvis during a lumbo–sacral junction. Unfortunately, not all radiographs were means to visualize a centre of a femoral head, creation it formidable to calculate a pelvic incidence, and in spin an accurate sacral slope measurement.

Article source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265596/

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