Harms and Melcher describe a posterior C1–C2 fixation technique using polyaxial screws in the C1 lateral masses and C2 pedicles, connected by rods. They report outcomes in the first 37 patients treated with this construct. The paper asks whether this approach is safe, achieves fusion, and solves the scenarios where Magerl transarticular screws are contraindicated.
When you see atlantoaxial instability on imaging, the first question is whether transarticular screws are safe — and roughly 1 in 5 patients will have vertebral artery anatomy that makes them too risky on at least one side.
This paper gives you the alternative: C1 lateral mass screws and C2 pedicle screws connected by a rod, placed individually so that reduction happens after screw insertion using the implants as handles. Unlike Brooks or Gallie wiring, the Harms construct requires no intact C1 arch, no structural graft, no wire passage into the canal, and no halo. A soft collar suffices in nearly all patients.
For young patients with rotatory subluxation or certain fractures, the technique also permits temporary fixation: remove the hardware at 3–4 months and the patient recovers C1–C2 motion because the joint was never violated.
This paper established the Harms construct as the go-to alternative when Magerl screws are contraindicated, and it remains the standard framing for C1–C2 fixation decisions in modern spine surgery.
Harms and Melcher describe a posterior C1–C2 fixation technique using polyaxial screws in the C1 lateral masses and C2 pedicles, connected by rods. They report outcomes in the first 37 patients treated with this construct. The paper asks whether this approach is safe, achieves fusion, and solves the scenarios where Magerl transarticular screws are contraindicated.
When you see atlantoaxial instability on imaging, the first question is whether transarticular screws are safe — and roughly 1 in 5 patients will have vertebral artery anatomy that makes them too risky on at least one side.
This paper gives you the alternative: C1 lateral mass screws and C2 pedicle screws connected by a rod, placed individually so that reduction happens after screw insertion using the implants as handles. Unlike Brooks or Gallie wiring, the Harms construct requires no intact C1 arch, no structural graft, no wire passage into the canal, and no halo. A soft collar suffices in nearly all patients.
For young patients with rotatory subluxation or certain fractures, the technique also permits temporary fixation: remove the hardware at 3–4 months and the patient recovers C1–C2 motion because the joint was never violated.
This paper established the Harms construct as the go-to alternative when Magerl screws are contraindicated, and it remains the standard framing for C1–C2 fixation decisions in modern spine surgery.