Radiographic variables that may predict clinical outcomes in cervical disk replacement surgery

Area of Science:

• Spine surgery
• Orthopedics
• Biomechanical engineering

Background:

• Predicting clinical outcomes after cervical disk replacement (CDR) is crucial for patient management.
• The association between radiographic parameters and functional outcomes following CDR remains unclear.

Purpose of the Study:

• To identify specific radiographic parameters that predict clinical outcomes after CDR surgery.
• To determine if preoperative and postoperative radiographic measurements correlate with patient-reported functional improvements.

Main Methods:

• Retrospective analysis of prospectively collected data from the Discover artificial cervical disk IDE trial.
• Evaluation of 56 radiographic variables and clinical outcomes (Neck Disability Index, visual analog pain scale, SF-36 PCS) in 171 patients with at least 1-year follow-up.
• Definition of poor clinical outcome as failure to achieve the minimal clinically important difference (MCID) in Neck Disability Index.

Main Results:

• A preoperative disk height of less than 3.5 mm was associated with a 3.4-fold increased risk of not achieving the NDI MCID (P=0.018).
• An increase in functional spinal unit angle by more than 3 degrees correlated with a 3.5-fold increased risk of not achieving the NDI MCID (P=0.016).
• Patients failing to achieve NDI MCID commonly exhibited multiple abnormal radiographic findings.

Conclusions:

• Decreased preoperative disk space height is a significant predictor of poorer clinical outcomes after CDR.
• Excessive postoperative segmental lordosis is also associated with suboptimal functional results following cervical disk replacement.