ABSTRACT
Vertebral body replacement is well-established to stabilize vertebral injuries due to trauma or cancer. Spinal implants are mainly manufactured by metallic alloys; which leads to artifacts in radiological diagnostics; as well as in radiotherapy. The purpose of this study was to evaluate the biomechanical data of a novel carbon fiber reinforced polyetheretherketone (CF/PEEK) vertebral body replacement (VBR). Six thoracolumbar specimens were tested in a six degrees of freedom spine tester. In all tested specimens CF/PEEK pedicle screws were used. Two different rods (CF/PEEK versus titanium) with/without cross connectors and two different VBRs (CF/PEEK prototype versus titanium) were tested. In lateral bending and flexion/extension; range of motion (ROM) was significantly reduced in all instrumented states. In axial rotation; the CF/PEEK combination (rods and VBR) resulted in the highest ROM; whereas titanium rods with titanium VBR resulted in the lowest ROM. Two cross connectors reduced ROM in axial rotation for all instrumentations independently of VBR or rod material. All instrumented states in all planes of motion showed a significantly reduced ROM. No significant differences were detected between the VBR materials in all planes of motion. Less rigid CF/PEEK rods in combination with the CF/PEEK VBR without cross connectors showed the smallest reduction in ROM. Independently of VBR and rod material; two cross connectors significantly reduced ROM in axial rotation. Compared to titanium rods; the use of CF/PEEK rods results in higher ROM. The stiffness of rod material has more influence on the ROM than the stiffness of VBR material.
ABSTRACT
BACKGROUND: Cerebrospinal fluid (CSF) leaks are a well-known complication of transsphenoidal surgery. Several autologous and artificial grafts have been used to close the sellar floor in an attempt to prevent postoperative CSF rhinorrhea. OBJECTIVE: To evaluate and describe a sandwich technique to close the sellar floor using autologous bone, absorbable gelatin sponge, and coated collagen fleece. METHODS: We reviewed 50 consecutive patients between April 2010 and August 2011 who underwent transsphenoidal surgery ending with reconstruction of the sellar floor with a particular sandwich technique. Patients with an intraoperative CSF leak received an additional lumbar drain. RESULTS: There were no cases of CSF rhinorrhea at postoperative follow-up after 6 weeks and no revision surgery. CONCLUSION: The proposed sandwich technique for closure of the sellar floor to the sphenoid sinus is a suitable alternative to autologous grafts and seems to be effective in preventing CSF rhinorrhea.
