Accuracy of Bony Gutter Placement in Cervical Laminoplasty Assisted by 3-D Print Modeling, and Associations with Posterior Spinal Cord Shift and Radiculopathy

Clinical applications of 3D printing in spine surgery: a systematic review

PURPOSE

The objective of this systematic review is to present a comprehensive summary of existing research on the use of 3D printing in spinal surgery.

METHODS

The researchers conducted a thorough search of four digital databases (PubMed, Web of Science, Scopus, and Embase) to identify relevant studies published between January 1999 and December 2022. The review focused on various aspects, including the types of objects printed, clinical applications, clinical outcomes, time and cost considerations, 3D printing materials, location of 3D printing, and technologies utilized. Out of the 1620 studies initially identified and the 17 added by manual search, 105 met the inclusion criteria for this review, collectively involving 2088 patients whose surgeries involved 3D printed objects.

RESULTS

The studies presented a variety of 3D printed devices, such as anatomical models, intraoperative navigational templates, and customized implants. The most widely used type of objects are drill guides (53%) and anatomical models (25%) which can also be used for simulating the surgery. Custom made implants are much less frequently used (16% of papers). These devices significantly improved clinical outcomes, particularly enhancing the accuracy of pedicle screw placement. Most studies (88%) reported reduced operation times, although two noted longer times due to procedural complexities. A variety of 3DP technologies and materials were used, with STL, FDM, and SLS common for models and guides, and titanium for implants via EBM, SLM, and DMLS. Materialise software (Mimics, 3-Matic, Magics) was frequently utilized. While most studies mentioned outsourced production, in-house printing was implied in several cases, indicating a trend towards localized 3D printing in spine surgery.

CONCLUSIONS

3D printing in spine surgery, a rapidly growing area of research, is predominantly used for creating drill guides for screw insertion, anatomical models, and innovative implants, enhancing clinical outcomes and reducing operative time. While cost-efficiency remains uncertain due to insufficient data, some 3D printing applications, like pedicle screw drill guides, are already widely accepted and routinely used in hospitals.

Accuracy of the Gutter Position in Cervical Double-door Laminoplasty Using Intraoperative Computed Tomography Navigation and the Factors Associated With C5 Palsy

STUDY DESIGN

This was a prospective study.

OBJECTIVE

This study aimed to investigate the accuracy of the gutter position after cervical double-door laminoplasty (LP) using intraoperative computed tomography (CT) navigation and the factors associated with C5 palsy.

SUMMARY OF BACKGROUND DATA

There were some reports in which the gutter position and the width of decompression in cervical LP were associated with C5 palsy; however, there were few reports about the accuracy of the gutter position.

MATERIALS AND METHODS

Thirty-three patients treated with cervical LP were enrolled. We marked our targeted gutter position on the lamina with a high-speed drill using intraoperative CT navigation and performed the LP procedure. The accuracy of the gutter position was evaluated with a postoperative CT scan. We measured the angle of the opened lamina (AOL), the proportion of the distance between the gutters and the distance of transverse diameter of spinal canal (PGSC) with a postoperative CT scan and spinal cord posterior shifting (SCPS) with preoperative and postoperative magnetic resonance imaging scans. We investigated the incidence of C5 palsy and analyzed AOL, PGSC, and SCPS between the C5 palsy (+) and (-) groups.

RESULTS

The accuracy of all gutter positions was 78.4% (182/232). The accuracy of the gutter position at the right C4 and right C7 was lower than that at the other levels. The AOL in all cases was ~60 degrees. The PGSC was 90.1%-97.2%. The SCPS at C5 was the largest with 2.2 mm. C5 palsy occurred in 3 of 33 patients (9.1%). There were no significant differences in the AOL, PGSC, or SCPS between the 2 groups.

CONCLUSIONS

The accuracy of the gutter position using intraoperative CT navigation was good. The incidence of C5 palsy was higher in this study than in the previous reports.