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The ideal surgical treatment of multilevel cervical spondylosis remains unclear. This study analyzed the complications in using titanium cages and plating to reconstruct multilevel cervical corpectomies. This was a retrospective analysis of 21 consecutive patients who had multilevel cervical corpectomies and reconstruction with titanium cages and anterior plating. Sixteen had 2-level, one had 2.5-level, three had 3-level, and one had 3.5-level corpectomies. All had reconstruction with titanium cages and anterior plating. Thirty-three percent of the patients developed complications. Radiographs revealed bony consolidation in 95% of patients. Reconstructing multilevel cervical corpectomies with titanium cages and plating is associated with complications. Advantages include rigid immobilization and the avoidance of iliac crest bone graft harvesting. Major complications are largely the result of failures of the cage and plate construct, especially in patients with osteopenic bone. Supplemental posterior stabilization may be considered for cases with spasticity or greater than 2-level corpectomies with profound osteoporosis.

The effect of a plasma-sprayed hydroxylapatite (HA) coating on the degree of bone ingrowth and interface shear attachment strength was investigated using a canine femoral transcortical implant model. Cylindrical implants were fabricated by sintering spherical Co-Cr-Mo particles 500-710 microns in diameter; the nominal implant dimensions were 5.95 +/- 0.05 mm diameter by 18 mm in length. One half of each implant was coated with hydroxylapatite, 25-30 microns in thickness, by a plasma-spray technique. Using strict aseptic technique, the implants were placed through both femoral cortices into defects approximately 0.05 mm undersized. After 2, 4, 6, 8, 12, 18, 26, and 52 weeks, the implants were harvested and subjected to mechanical pullout testing and undecalcified histologic evaluation. The application of the HA coating to porous implants enhanced both the amount of bone ingrowth and the interface attachment strength at all time periods. These differences were statistically significant for the percent of bone ingrowth at the 4-, 6-, 12-, 18-, 26-, and 52-week time periods, and interface shear strength values were significantly different at the 6-, 8-, 12-, 18-, and 26-week time periods. The rate of development of interface strength and bone ingrowth was also more rapid for the HA-coated implants. No evidence of any disruption, mechanical failure, or biologic resorption of the HA coating was observed. The results of the present study--demonstrating a beneficial effect of the HA coating at all time periods--are believed to be due to the use of paired comparisons, which allow assessment of subtle differences that might otherwise have been obscured by normal biological variability.

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