الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
LSTV are predisposed to a distinctive pattern of problems. In spite of their high prevalence, a little is understood about their biomechanics. LSTV alters the whole pelvic anatomy, it also affects the distribution of gravitational forces. In a normal spine, the L5–S1 unit, the flexible most caudal part of the spine, is subjected to the largest forces and consequently has a high prevalence of degenerative changes. As suggested before, in LSTV cases, the disc between the last lumbar and first sacral vertebra is “protected” and this may cause increased degeneration of the penultimate disc. Hence, LSTV is considered a risk factor for disc degenerative changes at the cephalad level. This could be caused by hypermobility and altered stresses which become concentrated at the level superjacent to LSTV immediately. Long term follow-up studies among young adults and adolescents would be essential to assess the added risk factors for early disc degeneration in LSTV.
The present study was conducted in order to estimate the incidence of LSTV among all cases who undergone lumbosacral surgical procedures including laminectomy, foraminectomy, micronucleotomy and PLIF.
This study was done on 288 patients who undergone lumbosacral surgical procedures at EL Hadara University Hospital. These patients were divided into two groups, group A (with LSTV) which included 133 patients and group B (without LSTV) which included 155 patients.
Inclusion criteria included single level PLIF, double level PLIF, three level PLIF, laminectomy and micronucleotomy.
Patients with spinal Trauma, spinal tumours and Adult Idiopathic Scoliosis were excluded from this study.
Pain was assessed preoperatively and postoperatively for 12 months using the visual analog scale (VAS) and Oswestry Disability Index (ODI).
After approval of the Ethics Committee, Faculty of Medicine, Alexandria University, an informed consent was obtained from every patient included in this study.
The present study revealed the following results:
• The overall incidence of LSTV among cases who undergone lumbosacral surgical procedures at was 46.2 %.
• Incidence of lumbar canal stenosis, degenerative spondylolithesis was higher in LSTV group compared to non-LSTV group.
• Incidence of disc prolapsed was higher in non-LSTV group compared to LSTV group.
• Incidence of disc prolapse and degenerative spondylolithesis at L4-5 level was higher in LSTV group com