Background: The disc prolapse is a common condition especially in young adults. Different levels are affected in the lumber region; the L4/L5 disc is more susceptible to longitudinal load and is the most common site of lumbar disc prolapse. The L5/S1 disc is protected from torsion load by strong ilio-lumbar ligaments but it is more susceptible to axial compressive forces. Many factors affect the result and outcome of surgery in these levels.Objective: The aim of this study is to correlate operative data, short-term results, complications, and prognostic factors (age, gender, mobility, hospital stay, and level of pain) for one-level lumber discectomybetween different levels (L4–L5 vs. L5–S1).Methods In this prospective study, 32 patientsin Al-Yarmouk teaching hospital undergoing survey form March 2008-December 2012.Six patients were excluded from this study because they were diabetics and multilevel disc degeneration .Fifteen (57.6%) patients undergoL5-S1 discectomy and 11 (42.4%) patients undergoL4-5 discectomy. Questionnaires for leg and back pain intensity (Visual Analogue Scale ;VAS), duration of leg pain, and disability (Oswestry Disability Index; ODI), were obtained preoperatively, 3 months, 6 months, 1-year- and 2 year follow-up.Analyses were utilized to evaluate the relationship between surgical outcomes and variable (gender, age, lumber segment, pre-operative ODI, and pre-operative VAS).Results: Mean operative time was[73.44 ± 26.25] min, mean hospital stay was [3-7] days, and mean mobilitywas [2.55 ± 0.93] days. At 2-year follow up, patients revealed a statistical significant improvement inVAS pain (P < 0.05), and ODI lumbar function (P < 0.05).The complications rate were 20.3 %.Our study elaborates good results for one-segmental L5-S1overL4-L5 discectomy. Discectomy of the L4–L5 disc wasassociated with an increased risk of complication (P < 0.05). The comparison revealed that operative time was influenced by age (P = 0.034); hospital stay was influenced by level (P = 0.036) and pre-op VAS (P = 0.006); while complications were influenced by level (P = 0.001) and pre-op ODI (P = 0.049Conclusion: The study revealed significant results for L5-S1 discectomy over L4-L5 discectomy in the late follow up period; the complications rate were higher in L4-L5 level discectomy
A theoretical model is developed to determine time evolution of temperature at the surface of an opaque target placed in air for cases characterized by the formation of laser supported absorption waves (LSAW) plasmas. The model takes into account the power temporal variation throughout an incident laser pulse, (i.e. pulse shape, or simply: pulse profile).
Three proposed profiles are employed and results are compared with the square pulse approximation of a constant power.