3D Printed Drilling Templates Improve Safety of Expansive Open-Door Laminoplasty for Cervical Myelopathy

Cervical myelopathy—when the spinal cord in the neck is compressed by bone spurs, herniated discs, or stenosis—can cause numbness, weakness, and balance problems. For people with multi-level disease (affecting multiple vertebrae), expansive open-door laminoplasty (EOLP) is a common surgery: it opens the lamina (the bony “roof” of the spinal canal) to relieve pressure. But EOLP has risks: complete fractures on the “hinge” side (the uncut edge that keeps the lamina stable) and re-closure of the decompressed area can worsen nerve function.

A team from the Department of Orthopedics at West China Hospital, Sichuan University, tested a solution: 3D printed patient-specific drilling templates. Their goal? Make EOLP safer by guiding surgeons to the exact spot for the hinge-side trough—reducing fractures and complications. Here’s what they found.

How the 3D Templates Work

The process starts with a pre-operative CT scan of the patient’s neck. Using Mimics 17.0 software (Materialize, Belgium), the team 3D-reconstructed the cervical spine and designed a template that fits exactly on the lamina. The template marks two paths:

Open side: A full cut through the lamina.
Hinge side: A shallow trough (not a full cut) at the ideal spot—the junction of the lamina and lateral mass (a bony projection on the vertebra).

The template was printed in acrylate resin via stereolithography (Beijing AK Medical Co., Ltd.), sterilized, and used during surgery. Surgeons pressed the template onto the lamina, cut the open side fully, and created the hinge trough along the guided path. They then opened the lamina, decompressed the spinal canal, and fixed it with a mini-plate (Medtronic Sofamor Danek).

Results: Fewer Fractures, Better Outcomes

The study included 22 patients (13 men, 9 women, average age 57) who had EOLP from C3 to C7 between 2016 and 2018. Over 12 months of follow-up:

Neurological improvement: Japanese Orthopedic Association (JOA) scores—used to measure nerve function—rose from an average of 8.6 before surgery to 14.3 at 12 months.
Less pain: Visual Analog Scale (VAS) scores for neck pain dropped from 5.7 to 2.8.
Lower fracture rates: Only 14.5% of hinge sides had complete fractures (16 out of 110 levels). This is far lower than the 56.8% rate reported in earlier studies (Chen et al., 2016).
No re-closure: All fractured hinges fused within a year (81.3% at 3 months, 100% at 12 months), and no lamina re-closed.
Minor complications: Three patients had temporary neck/shoulder pain (resolved with therapy), one had cerebrospinal fluid (CSF) leakage (fixed with drainage), and one had transient C5 palsy (arm weakness that recovered in a month). No problems were linked to the 3D templates.

Why This Matters

Hinge fractures are dangerous because they threaten the stability of the opened lamina. Previous research (Lee et al., 2018) found that fractures are 3x more likely if the trough is too medial (over 1.9mm from the pedicle). The 3D templates eliminated this risk by guiding surgeons to the exact right spot—no guesswork, no misplacement.

Compare this to earlier results: The team’s 2016 study found 56.8% of hinge sides fractured, with 3.7% of fragments displacing into the spinal canal. With templates, that rate plummeted to 14.5%—and all fractures healed without issue.

What This Means for Patients

For people with multi-level cervical myelopathy, 3D printed templates offer a safer EOLP. The precision reduces hinge fractures, lowers complication risks, and improves long-term stability. And because the templates are custom-made for each patient, surgeons can focus on decompression—not worrying about where to cut.

This study was published in the Chinese Medical Journal in 2019 by Kang-Kang Huang, Xin Rong, Hao Liu, Bei-Yu Wang, Hua Chen, and Ying Hong. For full details, read the original paper: doi.org/10.1097/CM9.0000000000000476

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