Object The objective of this study was to compare the stiffness and range of motion (ROM) of 4 cervical spine constructs and the intact condition. The 4 constructs consisted of 3-level anterior cervical discectomy with anterior plating, 1-level discectomy and 1-level corpectomy with anterior plating, 2-level corpectomy with anterior plating, and 2-level corpectomy with anterior plating and posterior fixation. Methods Eight human cadaveric fresh-frozen cervical spines from C2–T2 were used. Three-dimensional motion analysis with an optical tracking device was used to determine motion following various reconstruction methods. The specimens were tested in the following conditions: 1) intact; 2) segmental construct with discectomies at C4–5, C5–6, and C6–7, with polyetheretherketone (PEEK) interbody cage and anterior plate; 3) segmental construct with discectomy at C6–7 and corpectomy of C-5, with PEEK interbody graft at the discectomy level and a titanium cage at the corpectomy level; 4) corpectomy at C-5 and C-6, with titanium cage and an anterior cervical plate; and 5) corpectomy at C-5 and C-6, with titanium cage and an anterior cervical plate, and posterior lateral mass screw-rod system from C-4 to C-7. All specimens underwent a pure moment application of 2 Nm with regards to flexion-extension, lateral bending, and axial rotation. Results In all tested motions the statistical comparison was significant between the intact condition and the 2-level corpectomy with anterior plating and posterior fixation construct. All other statistical comparisons between the instrumented constructs were not statistically significant except between the 3-level discectomy with anterior plating and the 2-level corpectomy with anterior plating in axial rotation. There were no statistically significant differences between the 1-level discectomy and 1-level corpectomy with anterior plating and the 2-level corpectomy with anterior plating in any tested motion. There was also no statistical significance between the 3-level discectomy with anterior plating and the 2-level corpectomy with anterior plating and posterior fixation. Conclusions This study demonstrates that segmental plate fixation (3-level discectomy) affords the same stiffness and ROM as circumferential fusion in 2-level cervical spine corpectomy in the immediate postoperative setting. This obviates the need for staged circumferential procedures for multilevel cervical spondylotic myelopathy. Given that the posterior segmental instrumentation confers significant stability to a multilevel cervical corpectomy, the surgeon should strongly consider the placement of segmental posterior instrumentation to significantly improve the overall stability of the fusion construct after a 2-level cervical corpectomy.

Study DesignRetrospective comparative study and technical note.PurposeTo determine if there is a difference in clinical and radiographic parameters between unilateral and bilateral kyphoplasty in a uniform cancer population and to stress the importance of preoperative planning.Overview of LiteratureWhile unipedicular kyphoplasty is gaining popularity, a few comparative studies have reported on superior kyphotic reduction with the bipedicular approach.MethodsWe reviewed 69 myeloma patients with 105 operated levels (51 levels were done bilaterally vs. 54 unilaterally). Pain reduction, height restoration, cement volume and complications were recorded up to three months postoperatively. A technical note to identify the skin entry point on the basis of the magnetic resonance imaging and fluoroscopy (lateral view) is being described.ResultsBoth procedures resulted in significant pain reduction (5.4-5.6/10 points, p=0.8). There was significant height restoration after the operation (p<0.001), while there was no sustained difference between the procedures (p=0.5) up to three months postoperatively. More cement was injected in the bilateral group (4.1 mL vs. 4.9 mL, p=0.002); no difference in cement extravasation in the spinal canal was observed (p=0.5).ConclusionsThere was no difference in the clinical or radiological outcomes between the unilateral and bilateral approaches. Therefore, unilateral kyphoplasty may be performed whenever it is technically feasible and this may be determined preoperatively.

This research is concerned with the estimation of farmer's demand for chemical fertilizers. The data were collected from a sample of farmers in two villages in Bani Sewaf Governorate in the summer of 2015. Most farmers use two kinds of fertilizers; namely urea and superphosphates. Urea is provided to farmers in certain quotas at subsidized prices through the government controlled agricultural cooperatives. Farmers however find it necessary to rely on the free market to supplement the subsidized quotas of urea.The research begins by estimating the Cobb-Douglas production functions for two field crops which are wheat and maize. Then the production functions coefficients are used to calculate the underlying cost functions. From the cost functions we were able to drive the conditional demand functions for chemical fertilizers with the help of Shephard's lemma.The estimates of all functions seem reasonable and consistent with economic theory. The elasticities of wheat production with respect to urea and superphosphates are 0.27 and 0.03 respectively. The wheat cost function is an increasing function in input prices and in output level. The conditional demand function for urea in wheat production is homogenous of degree zero in input prices; that is doubling the input prices will leave the demand for urea unchanged.Similar results for the maize crop were attained. The maize production elasticities with respect to urea and superphosphates are 0.16 and 0.06 respectively. The results are statistically significant. The isoquant equation indicates that decreasing urea application by 0.42 sack can be compensated by increasing superphosphates application by one sack in order to keep the level of maize production at 18 ardab per feddan. The conditional demand function for urea reveals that an increase in the price of urea by EGP 5 would reduce the demand for urea by 0.78 sacks.

This study was conducted in the NorthCoastal Zone of Egypt (NCZE); with the objective of identifying the socioeconomic characteristics of the small ruminant breeders .This study aims to assess the economic performance of sheep production and to determine influence of socioeconomic factors on sheep production performance under different wateravailability. A total of 100 breeders were interviewed. A structured questionnaire was designed to obtain information regarding socioeconomic characteristics of households, animal productivity, input and output parameters and annual production costs and revenues. Barkisheep are the main prevailing breed raised in the study area. The contribution of livestock to household income ranges from 50.34 % to 74.3%. Sheep contribute up to 74.56 % of the net cash income derived from livestock production in the rain fed region. Flock location, household experience, occupation, family size and farm size had a significant (P<0.05) impact on sheep profitability. On the other hand, farmer"s age,education and livestock holding had no effect on the profitability of sheep production. The findings of the study indicate that farmersin the NCZE are in need of financial and technical support in order to increase their income.