A modified measurement method for functional spinal unit ROM of cervical spine

Area of Science:

• Orthopedics
• Spinal Surgery
• Radiology

Background:

• The interspinous process motion (ISM) method offers more accurate assessment of cervical fusion than the Cobb angle method.
• However, ISM results in millimeters are not directly comparable to Cobb angle data.
• Accurate measurement of cervical functional spinal unit range of motion (FSU ROM) is crucial for evaluating surgical outcomes.

Purpose of the Study:

• To introduce a modified measurement method (M1) for cervical FSU ROM.
• To evaluate the repeatability and reliability of M1 in measuring ROM after cervical artificial disc replacement.
• To compare M1 with the traditional Cobb angle measurement method (M2).

Main Methods:

• Retrospective review of 81 patients undergoing cervical artificial disc replacement.
• Measurement of postoperative FSU ROM using dynamic cervical radiographs.
• Application of the modified method (M1) and the traditional Cobb angle method (M2).

Main Results:

• No statistically significant difference between M1 and M2 (P > 0.05).
• Strong linear correlation between M1 and M2 (correlation coefficient = 0.947, P < 0.01).
• M1 demonstrated higher intra-observer (ICC=0.957) and inter-observer (ICC=0.947) reliability than M2 (0.889 and 0.874, respectively).
• M1 yielded lower SEM (0.64° vs 1.14°) and MDC (1.49° vs 2.66°) compared to M2.

Conclusions:

• The modified measurement method (M1) is repeatable and reliable for assessing cervical FSU ROM post-surgery.
• M1 provides higher measurement precision than the traditional Cobb angle method.
• This modified method enhances the evaluation of surgical outcomes after cervical artificial disc replacement.