Relationship between the laminoplasty opening size and the laminoplasty opening angle, increased sagittal canal diameter and the prediction of spinal canal expansion following open-door cervical laminoplasty

Abstract

Objective To clarify the relationship between the laminoplasty opening size (LOS), the laminoplasty opening angle (LOA) and the increase in sagittal canal diameter (SCD) and to predict the amount of canal enlargement during open-door cervical laminoplasty (ODCL). Methods Formula describing the relationship between LOS and LOA, the increase in SCD was deduced. The parameters of pre-and postoperative computed tomography scans of 36 patients who had undergone laminoplasty surgery were measured by picture archiving and communication system (PACS) software, and the amount of canal enlargement of these patients was predicted when the opening size of laminoplasty was 8, 10, 12, 14 and 16 mm according to the formula. Results For equivalent LOS, the amount of canal enlargement with each opening size differed throughout the cervical region. When the C3-C7 LOS was 10 mm the SCD increased [4.1 mm, and the canal area increased in C3-C6 [88 mm 2 , and the canal area increased in C7 [ 80 mm 2 .When the C3-C7 LOS was 12 mm, the SCD increased [5.2 mm, and the canal area increased in C3-C6 [104 mm 2 , and the canal area increased in C7 [ 94 mm 2 . Conclusion Formula accurately showed the relationship between the LOS and the increase in SCD achieved by ODCL. The amount of canal enlargement following ODCL could be predicted by the formula. LOS of 10-12 mm at C3-C7 might be optimal during ODCL.

Clinical Investigation of the Association of Opening Size with Sagittal Canal Diameter Based on Single-Door Cervical Laminoplasty

“…It was found in other studies that recovery of post-operative nerve function was closely related to the SCD and LOS [15,21]. The post-operative SCD increment seems to be more important than spinal canal area enlargement in alleviating spinal cord compression [10,22].…”

“…Itoh and Tsuji reported that a SCD increment of 4.1 mm is optimum and could be obtained via LOS enlargement to 8 mm [14]. Some researchers proposed the optimal post-operative SCD increment to be 4–5 mm in SDCL [1,15].…”

“…Multiple trials have assessed the association of LOS with SCD [1,14,15]. Nevertheless, the reported research findings were too complex to be widely adopted in clinical practice.…”

Impact of different laminae open angles on axial symptoms after expansive open-door laminoplasty

“…[ 6 – 8 ] Some studies noted that the lamina open angle should be small, excessive opening angle did not reduce the incidence of reclosure but increase occurrence of complications. [ 9 – 13 ] However, they did not continue to explore the relationship between the opening angle and axial symptoms. The objective of the present study was to explore the effect of different laminae open angles on postoperative axial symptoms and to discuss the possible mechanism of the impact of different open angles on axial symptoms.…”

Short-Term Clinical Evaluation of Enhanced Unilateral Open-Door Laminoplasty Using Titanium Mesh

“…Recently, ODL has been frequently opted by surgeons because from the long-term follow-up study, it has offered greater patient satisfaction with improvement on the motor scale, less risk than radical anterior approach, and superiority over conventional laminectomy. This procedure can preserve cervical spine stability, prevent canal stenosis due to scar formation, and cause less frequent axial pain [ 6 - 8 ].…”