الفهرس 
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Abstract
Cervical radiculopathy is a common, disabling, nonfatal symptom. It can result from a number of pathologic processes. These include a soft disc herniation, progressive disc degeneration without a frank herniation, anterior cervical osteophytes, uncal or postero-lateral osteophytes, and facet joint hypertrophy.
The optimal management and long-term treatment outcomes of patients with cervical radiculopathy are still debated. In some patients, radiculopathy develops insidiously and becomes unremitting, seriously disrupting work, social activities, and recreation. Unless there is clear evidence of progressive weakness, associated myelopathic signs, or unbearable pain, surgical intervention is generally reserved for patients with unremitting and progressive symptoms in whom medical treatment has failed. In the absence of clear neurologic deficit, the severity, duration, and nature of pain are often the most decisive factors in determining whether surgery is recommended or not.
Anterior cervical discectomy is a recognized treatment option of degenerative cervical disc diseases. The anterior approach allows direct visualization of the entire interspace and wide decompression of the anterior aspect of cervical spinal cord and nerve roots.
The interbody fusion after cervical discectomy can greatly help to minimize post-operative morbidity. The advantages of the interbody fusion includes: 1) Maintenance of cervical alignment; 2) Arrest of spur formation or resorption of spur; 3) Elimination of potential instability; 4) Reservation of the physiological lordosis and disc height, thereby reducing potential compromise of the neural foramen.
A controversy exists regarding the best option available aiming for inter-body fusion among patients with cervical disc disease. Pseudarthrosis has been shown to adversely affect clinical results after anterior cervical disc fusion.
Autogenous cancellous bone graft represents the most effective graft material for achieving spinal fusion. Anterior instrumentation is now frequently performed at the time of anterior cervical disc fusion to improve fusion rates. Anterior plates provide stability following decompression and fusion of the cervical spine. Advantages include earlier patient’s mobilization, cost effectiveness, a decreased need for orthotics, a diminished rate of graft dislodgment and migration, superior fusion rates, immediate stabilization and the prevention of spinal deformity.
For some time, the most commonly used anterior cervical plating systems have been static devices where the screws are rigidly locked to the plate. These plates are designed to rigidly immobilize the treated level and reduce micromotion at the graft–bone interfaces, with the goals of reducing risks of instrumentation failure and improving fusion rates.
Others have suggested that the rigidity of these plating systems will cause stress shielding across the graft which may in fact adversely affect graft healing. Recently dynamic cervical plates have been introduced to address this concern by allowing for load sharing across the graft construct. Various methods of dynamization have been proposed. Slotted holes in the plate, variable angle or toggling screws, and self-adjusting plate lengths have all been commercialized. Dynamic plate systems allow for load-sharing without apparent loss of rigidity.
Spinal cage instrumentation to enhance spinal fusion and stability in cervical spine surgery has ensured an adequate increase in the height and the cross-sectional area of the neural foramina and helped to correct cervical kyphosis.
Different cage types have been introduced to neurosurgical practice. Although the early results with the cages were satisfactory, problems such as migration, subsidence and structural failure of the cage with some difficulties in postoperative magnetic resonance imaging were observed.
PEEK cages have recently been used in cervical surgery. PEEK is polyetheretherketone, a semi-crystal polyaromatic linear polymer. The use of a PEEK cage is becoming popular because of better elasticity and radiolucency.
In this study, we evaluated the clinical and radiological outcome after the stand alone use of PEEK cervical cage for cervical body fusion in patients with cervical disc disease who are going to be subjected to single or double level anterior cervical discectomy, and to compare the results with those after the use of autogenous tricortical iliac crest bone graft combined with anterior cervical dynamic plate. The study was carried out as a prospective randomized study among a total of 40 patients prepared for anterior cervical discectomy, and categorized into two groups. Group 1 included 20 patients subjected to anterior cervical discectomy with PEEK cages fusion while group 2 included 20 patients were subjected to anterior cervical discectomy with iliac crest tricortical autograft fusion combined with anterior cervical dynamic plate.
The study results showed that mean age was 48.2 years old in group 1 (Cage group) and 47.5 years old in group 2 (Plate group). The comparison between both groups regarding change in clinical assessment parameters during period of follow up revealed that there was no statistically significant difference between both groups regarding quadriple visual analogue score, or Japanese Orthopedic association score during any time point of follow up period (3 months, 6 months and 1 year). Both groups showed significant improvement in the quadriple visual analogue score after 3 months postoperative, 6 months and at end of follow up period, while patients started to show significant improvement in Japanese Orthopedic association score after 6 months of follow up.
There was no statistically significant difference between both groups as regard to patient satisfaction at the end of follow up period. Most of patient reported good satisfaction about the procedure (60% in group 1 and 55% in group 2). Only one patient in group 2 reported that the procedure was poor.
Mean preoperative disc height was 4.71mm and 5.1mm in group 1 and group 2 respectively. Both procedures resulted in significant increase in disc height immediately postoperative to 9mm and 9.02mm in both groups respectively. At end of follow up there was slight not significant loss in disc height during healing process to 8mm and 8.5mm in both groups respectively. Mean loss of disc height during follow up period was 1.5mm in group 1 and 1.3mm in group 2 with no significant difference.
Lordosis angle preoperatively was -12.5 degrees in group 1 and -11.7 degrees in group 2 with no significant difference. Both procedures caused significant immediate postoperative gain of fused segment lordosis that was 9.9 degrees in group 1 and 10.1 degrees in group 2 with no significant difference between both groups. At end of follow up there was loss of lordosis with both procedures in mean of 3.3 degrees in group 1 and 7.8 degrees in group 2 with statistically significant difference between both groups. At end of follow up; loss of lordosis was significantly higher in group 2 (plate group) decreasing lordosis angle from -21.8 immediate postoperatively to -14.2 at end of follow up versus reduction of angle from -22.4 to -17.5 in group 1.
The mean cage subsidence in cage group was 1.4 mm with range from 0 to 3 mm. Cage subsidence was > 2 mm in six out of 26 levels in group 1 with range from 2 – 4 mm.
Non fusion was reported among 6 levels in group 1 and 4 levels in group 2. 11/26 levels showed grade IV fusion in group 1 versus 12/27 levels in group 2. Grade III fusion was reported among 8/26 levels in group 1 and 9/27 levels in group 2.
The incidence of complication was more prevalent with patients in group 2 however insignificant in most complications except for donor site pain.
Finally, it is concluded that Cages are better than the dynamic plates as regard to loss of lordosis angle but there is no statistically significant difference between both regarding the fusion rate.