The Imaging And Clinical Application Research On The Method Of Axis Pedicle Srew Fixation By Hand Within The Wall Of The Axis Isthmus

Objective: To search the bony mark of needling for atlantoaxial pedicle serew fixation,to produce a facility and precise needling technology foratlantoaxial pedicle screw fixation, and further explore the safety of its clinical application.Methods: Imaging measurements: 34 normal adult formed dimensional CT reconstruction of Axis, and measured the following indicators: 1. Measured the width of the upper edge, lower edge and the central ( L1,L2,L3) and height (L4) by left and right side of the pedicle; 2. Measured the distance between the upper the lower the central edge to the center line (L5,L6,L7) by left and right side of the isthmus; 3. Selected the pedicle transverse images with the width of not less than 5.0 mm, with diameter of 3.5 mm of the pedicle screw as the standard. Measured the left and right sides of the most lateral of the screw channel A and the most medial screw path B, and marked the nail Road entrance point(Ae,Be), recorded the length of the screw channel(La, Lb) and the angle with the midline(α1,α2) and the horizontal distance of the isthmus (L8,L9). Measured the best nail Road C(C is the midline through the pedicle narrowest vertical connection), and marked the nail Road entrance point(Ce),recorded the length of the screw channel(Lc) and the angle with the midline (α3), and the horizontal distance of the isthmus(L10).Clinical Application: 43 cases were set screw by using pedicle screw method from March 2006 to May 2009. Preoperative : 1. Measurement of the pedicle height and the upper edge of the central width to assess the feasibility of the fixation in this case of the pedicle screw. 2. Measured the horizontal distance to the edge of the pedicle isthmus, the length of the screw channel and the angle with the midline through the best entry points Ce. The others were the routine preparation of posterior cervical fixation. Along the entrance point Ce, within the pedicle isthmus along the strip on the edge of the horizontal distance from its lateral X mm(specific value was measured before operation by imaging), dipped into the nail within angle preoperative determinated, When the depth of the preoperative measurement of long nails was out of hand cone, and tapped screw implants with the power wire of a diameter of 3.0 mm. Observed wether had set screw-related complications during surgery, and the reconstruction of the location of screws by three-dimensional CT. Patients were followed up Every 3 months, were observated whether the fixation loosening, breakage and fusion results by Imaging.Results: Imaging measurements: 1.L1,L2,L3 and L4 were (7.67±1.72)mm,(6.21±1.43)mm,(4.28±1.06)mm,(8.60±0.67)mm respectively,No significant difference between left and right sides compared with each other (P> 0.05) ;2. L5,L6,L7 were(11.12±0.49)mm(,11.30±0.48)mm(,11.30±0.41)mm respectively,No significant difference between left and right sides compared with each other (P> 0.05),and No significant difference between the same sides compared with each other; 3. La,L8,α1 were(29.70±3.09)mm,(6.27±1.12)mm,(49.40±6.43)°respectively,No significant difference between left and right sides compared with each other (P> 0.05);4. Lb,L9,α2 were ( 28.87±2.27 ) mm, ( 2.66±1.10 ) mm, ( 6.65±1.14 )°respectively,No significant difference between left and right sides compared with each other (P> 0.05); 5. Lc,L10,α3 were(25.34±2.50)mm,(7.63±1.12)mm,(30.13±4.32)°respectively,No significant difference between left and right sides compared with each other (P> 0.05).Clinical Application: 86 Pedicle screws were placed,the upper edge of the Pedicle isthmus all has been well exposed, and Did not appear pedicle wall rupture,vertebral artery venous plexus bleeding,neck cord injury, C2 and C3 nerve root injury, and about blood loss was 320 ml during surgery,and about operation time was 135 min. Cases required surgical reduction of intraoperative C-arm X-ray machines are prompted to reset a good perspective. Postoperative three-dimensional CT were used to review and finded that intraoperative rupture of the lateral wall of pedicle screw channel for a small rupture, the one screw in the screw channel at or near the pedicle wall and a pedicle screw at or near the outer wall in the others. No vertebral artery injury, infection, cerebrospinal fluid leakage, spinal cord, C2 and C3 nerve root injury in all the cases after surgery. Patients were followed after 6 months,no loose or broken off in fixation and all reached the bone healing.Conclusions: There is a constant relationship of the anatomical location between Axis and the pedicle isthmus. The method of Axis pedicle srew fixation within the wall as an anatomic landmark is feasible, safe and effective. But this method must be under the individual guidance of imaging measurement.