Hsuan-Kan Chang, Jau-Ching Wu, Diego Shih-Chieh Lin, Chih-Chang Chang, Tsung-Hsi Tu, Wen-Cheng Huang and Henrich Cheng
Chih-Chang Chang, Ching-Lan Wu, Jau-Ching Wu, Hsuan-Kan Chang, Li-Yu Fay, Tsung-Hsi Tu, Wen-Cheng Huang and Henrich Cheng
Tsung-Hsi Tu, Chih-Chang Chang, Jau-Ching Wu, Li-Yu Fay, Wen-Cheng Huang and Henrich Cheng
The most commonly accepted indications for cervical disc arthroplasty (CDA) are 1- and 2-level cervical disc herniation or spondylosis causing radiculopathy or myelopathy that is refractory to medical management. Unlike anterior cervical discectomy and fusion (ACDF), which eliminates motion, CDA aims to restore the physiological range of motion of the indexed joint. Thus, the effect of indirect decompression gained by the insertion of a sufficiently large interbody graft and incorporation into arthrodesis after ACDF cannot be duplicated for CDA. For patients undergoing CDA, during extreme flexion/extension or rotation, the exiting nerve roots might be impinged by inadequately decompressed foraminal osteophytes. Therefore, the authors advocate generous decompression, including resection of the posterior longitudinal ligament (PLL) and bilateral uncovertebral joints (UVJs), even in the asymptomatic side. This video demonstrates full dural expansion and enlarged neuroforamen after removal of the PLL and UVJs. Venous hemorrhage encountered during foraminotomy can always be controlled by cottonoid packing or hemostatic agents. Also, the endplates of the surrounding vertebral bodies were meticulously prepared for parallel insertion of the ProDisc-C Nova (DePuy Synthes Spine) artificial disc. Please note that the ProDisc-C Nova is currently not available on the US market.
The video can be found here: https://youtu.be/XUo34j6WFYs.
Chih-Chang Chang, Jau-Ching Wu, Peng-Yuan Chang, Mei-Yin Yeh, Yi-Hsuan Kuo, Li-Yu Fay, Tsung-Hsi Tu, Wen-Cheng Huang and Henrich Cheng
There are many kinds of artificial discs available for cervical disc arthroplasty (CDA), with various designs of fixation and articulation mechanisms. Each of these designs has different features and theoretically fits most optimally in selected types of patients. However, there has been insufficient literature to guide individualized selection among these CDA devices. Since CDA aims to restore the joint function rather than arthrodesis, tailor-made size, shape, and mechanical properties should be taken into account for each candidate's target disc. Despite several large-scale prospective randomized control trials that have demonstrated the effectiveness and durability of CDA for up to 8 years, none of them involved more than one kind of artificial disc. In this video the authors present detailed steps and technical aspects of the newly introduced ProDisc-C Vivo (DePuy Synthes Spine), which has the same ball-and-socket design for controlled, predictable motion as the ProDisc-C. The newly derived teeth fixation provides high primary stability and multilevel capability by avoidance of previous keel-related limitations and complications (e.g., split vertebral fracture). Please note that the ProDisc-C Vivo is currently not available on the US market.
The authors present the case of a 53-year-old woman who had symptoms of both radiculopathy and myelopathy caused by a large, calcified disc herniation at C4–5. There was no improvement after 4 months of medical treatment and rehabilitation. A single-level CDA was successfully performed with the ProDisc-C Vivo, and her symptoms were completely ameliorated afterward. The follow-up images demonstrated preservation of motion at the indexed level.
The video can be found here: https://youtu.be/4DSES1xgvQU.
Hsuan-Kan Chang, Chih-Chang Chang, Tsung-Hsi Tu, Jau-Ching Wu, Wen-Cheng Huang, Li-Yu Fay, Peng-Yuan Chang, Ching-Lan Wu and Henrich Cheng
Many reports have successfully demonstrated that cervical disc arthroplasty (CDA) can preserve range of motion after 1- or 2-level discectomy. However, few studies have addressed the extent of changes in segmental mobility after CDA or their clinical correlations.
Data from consecutive patients who underwent 1-level CDA were retrospectively reviewed. Indications for surgery were medically intractable degenerative disc disease and spondylosis. Clinical outcomes, including visual analog scale (VAS)–measured neck and arm pain, Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) scores, were analyzed. Radiographic outcomes, including C2–7 Cobb angle, the difference between pre- and postoperative C2–7 Cobb angle (ΔC2–7 Cobb angle), sagittal vertical axis (SVA), the difference between pre- and postoperative SVA (ΔSVA), segmental range of motion (ROM), and the difference between pre- and postoperative ROM (ΔROM), were assessed for their association with clinical outcomes. All patients underwent CT scanning, by which the presence and severity of heterotopic ossification (HO) were determined during the follow-up.
A total of 50 patients (mean age 45.6 ± 9.33 years) underwent a 1-level CDA (Prestige LP disc) and were followed up for a mean duration of 27.7 ± 8.76 months. All clinical outcomes, including VAS, NDI, and JOA scores, improved significantly after surgery. Preoperative and postoperative ROM values were similar (mean 9.5° vs 9.0°, p > 0.05) at each indexed level. The mean changes in segmental mobility (ΔROM) were −0.5° ± 6.13°. Patients with increased segmental mobility after surgery (ΔROM > 0°) had a lower incidence of HO and HO that was less severe (p = 0.048) than those whose ΔROM was < 0°. Segmental mobility (ROM) was significantly lower in patients with higher HO grade (p = 0.012), but it did not affect the clinical outcomes. The preoperative and postoperative C2–7 Cobb angles and SVA remained similar. The postoperative C2–7 Cobb angles, SVA, ΔC2–7 Cobb angles, and ΔSVA were not correlated to clinical outcomes after CDA.
Segmental mobility (as reflected by the mean ROM) and overall cervical alignment (i.e., mean SVA and C2–7 Cobb angle) had no significant impact on clinical outcomes after 1-level CDA. Patients with increased segmental mobility (ΔROM > 0°) had significantly less HO and similarly improved clinical outcomes than those with decreased segmental mobility (ΔROM < 0°).