Beejal Y. Amin and Praveen V. Mummaneni
Tsung-Hsi Tu, Jau-Ching Wu, Li-Yu Fay, Chin-Chu Ko, Wen-Cheng Huang and Henrich Cheng
Cervical total disc replacement (TDR) is a viable option for the surgical treatment of degenerative disc disease. This 67-year-old nonsmoking male patient underwent single-level ProDisc-C cervical TDR at C5–6 without any intraoperative problem. His radicular pain improved and he had no neck pain immediately after the operation. However, on postoperative Day 3, a radiograph demonstrated a vertical split fracture of the C-5 vertebra. This fracture was managed conservatively, and 2 years postoperatively a follow-up CT scan demonstrated stable device position and fusion of the fracture. Although the linear fracture caused no neurological symptoms or device migration, the authors advocate prudence in selection and installation of keel-design prostheses, even in a single-level cervical TDR scenario.
Jau-Ching Wu, Wen-Cheng Huang, Hsiao-Wen Tsai, Chin-Chu Ko, Li-Yu Fay, Tsung-Hsi Tu, Ching-Lan Wu and Henrich Cheng
The most currently accepted indication for cervical arthroplasty is 1- or 2-level degenerative disc disease (DDD) refractory to medical treatment. However, the randomized and controlled clinical trials by the US FDA investigational device exemption studies only compared cervical arthroplasty with anterior cervical discectomy and fusion for 1-level disease. Theoretically, 2-level cervical spondylosis usually implicates more advanced degeneration, whereas the 1-level DDD can be caused by merely a soft-disc herniation. This study aimed to investigate the differences between 1- and 2-level cervical arthroplasty.
The authors analyzed data obtained in 87 consecutive patients who underwent 1- or 2-level cervical arthroplasty with Bryan disc. The patients were divided into the 1-level and the 2-level treatment groups. Clinical outcomes were measured using the visual analog scale (VAS) for the neck and arm pain and the Neck Disability Index (NDI), with a minimum follow-up of 30 months. Radiographic outcomes were evaluated on both radiographs and CT scans.
The study analyzed 98 levels of Bryan cervical arthroplasty in 70 patients (80.5%) who completed the evaluations in a mean follow-up period of 46.21 ± 9.85 months. There were 22 females (31.4%) and 48 males (68.6%), whose mean age was 46.57 ± 10.07 years at the time of surgery. The 1-level group had 42 patients (60.0%), while the 2-level group had 28 patients (40.0%). Patients in the 1-level group were younger than those in the 2-level group (mean 45.00 vs 48.93 years, p = 0.111 [not significant]). Proportional sex compositions and perioperative prescription of nonsteroidal antiinflammatory drugs were also similar in both groups (p = 0.227 and p = 1.000). The 2-level group had significantly greater EBL during surgery than the 1-level group (220.80 vs 111.89 ml, p = 0.024). Heterotopic ossification was identified more frequently in the 2-level group than the 1-level group (75.0% vs 40.5%, p = 0.009). Although most of the artificial discs remained mobile during the follow up, the 2-level group had fewer mobile discs (100% and 85.7%, p = 0.022) than the 1-level group. However, in both groups, the clinical outcomes measured by VAS for neck pain, VAS for arm pain, and NDI all significantly improved after surgery compared with that preoperatively, and there were no significant differences between the groups at any point of evaluation (that is, at 3, 6, 12, and 24 months after surgery).
Clinical outcomes of 1- and 2-level cervical arthroplasty were similar at 46 months after surgery, and patients in both groups had significantly improved compared with preoperative status. However, there was a significantly higher rate of heterotopic ossification formation and less mobility of the Bryan disc in patients who underwent 2-level arthroplasty. Although mobility to date has been maintained in the vast majority (94.3%) of patients, the long-term effects of heterotopic ossification warrant further investigation.
Li-Yu Fay, Wen-Cheng Huang, Jau-Ching Wu, Hsuan-Kan Chang, Tzu-Yun Tsai, Chin-Chu Ko, Tsung-Hsi Tu, Ching-Lan Wu and Henrich Cheng
Cervical arthroplasty has been accepted as a viable option for surgical management of cervical spondylosis or degenerative disc disease (DDD). The best candidates for cervical arthroplasty are young patients who have radiculopathy caused by herniated disc with competent facet joints. However, it remains uncertain whether arthroplasty is equally effective for patients who have cervical myelopathy caused by DDD. The aim of this study was to compare the outcomes of arthroplasty for patients with cervical spondylotic myelopathy (CSM) and patients with radiculopathy without CSM.
A total of 151 consecutive cases involving patients with CSM or radiculopathy caused by DDD and who underwent one- or two-level cervical arthroplasty were included in this study. Clinical outcome evaluations and radiographic studies were reviewed. Clinical outcome measurements included the Visual Analog Scale (VAS) of neck and arm pain, Japanese Orthopaedic Association (JOA) scores, and the Neck Disability Index (NDI) in every patient. For patients with CSM, Nurick scores were recorded for evaluation of cervical myelopathy. Radiographic studies included lateral dynamic radiographs and CT for detection of the formation of heterotopic ossification .
Of the 151 consecutive patients with cervical DDD, 125 (82.8%; 72 patients in the myelopathy group and 53 in the radiculopathy group) had at least 24 months of clinical and radiographic follow-up. The mean duration of follow-up in these patients was 36.4 months (range 24–56 months). There was no difference in sex distribution between the 2 groups. However, the mean age of the patients in the myelopathy group was approximately 6 years greater than that of the radiculopathy group (53.1 vs 47.2 years, p < 0.001). The mean operation time, mean estimated blood loss, and the percentage of patients prescribed perioperative analgesic agents were similar in both groups (p = 0.754, 0.652, and 0.113, respectively). There were significant improvements in VAS neck and arm pain, JOA scores, and NDI in both groups. Nurick scores in the myelopathy group also improved significantly after surgery. In radiographic evaluations, 92.5% of patients in the radiculopathy group and 95.8% of those in the radiculopathy group retained spinal motion (no significant difference). Evaluation of CT scans showed heterotopic ossification in 34 patients (47.2%) in the myelopathy group and 25 patients (47.1%) in the radiculopathy group (p = 0.995). At a mean of over 3 years postoperatively, no secondary surgery was reported in either group.
The severity of myelopathy improves after cervical arthroplasty in patients with CSM caused by DDD. At 3-year follow-up, the clinical and radiographic outcomes of cervical arthroplasty in DDD patients with CSM are similar to those patients who have only cervical radiculopathy. Therefore, cervical arthroplasty is a viable option for patients with CSM caused by DDD who require anterior surgery. However, comparison with the standard surgical treatment of anterior cervical discectomy and fusion is necessary to corroborate the outcomes of arthroplasty for CSM.
Tsung-Hsi Tu, Jau-Ching Wu, Wen-Cheng Huang, Hsuan-Kan Chang, Chin-Chu Ko, Li-Yu Fay, Ching-Lan Wu and Henrich Cheng
Heterotopic ossification (HO) after cervical arthroplasty is not uncommon and may cause immobility of the disc. To prevent HO formation, study protocols of clinical trials for cervical arthroplasty undertaken by the US FDA included perioperative use of nonsteroidal antiinflammatory drugs (NSAIDs). However, there are few data supporting the use of NSAIDs to prevent HO after cervical arthroplasty. Therefore, this study aimed to evaluate the efficacy of NSAIDs in HO formation and clinical outcomes.
Consecutive patients who underwent 1- or 2-level cervical arthroplasty with a minimum follow-up of 24 months were retrospectively reviewed. All patients were grouped into 1 of 2 groups, an NSAID group (those patients who had used NSAIDs postoperatively) and a non-NSAID group (those patients who had not used NSAIDs postoperatively). The formation of HO was detected and classified using CT in every patient. The incidence of HO formation, disc mobility, and clinical outcomes, including visual analog scale (VAS) scores of neck and arm pain, neck disability index (NDI) scores, and complications were compared between the two groups. Furthermore, a subgroup analysis of the patients in the NSAID group, comparing the selective cyclooxygenase (COX)-2 to nonselective COX-2 NSAID users, was also conducted for each of the above-mentioned parameters.
A total of 75 patients (mean age [± SD] 46.71 ± 9.94 years) with 107 operated levels were analyzed. The mean follow-up duration was 38.71 ± 9.55 months. There were no significant differences in age, sex, and levels of arthroplasty between the NSAID and non-NSAID groups. There was a nonsignificantly lower rate of HO formation in the NSAID group than the non-NSAID group (47.2% vs. 68.2%, respectively; p = 0.129). During follow-up, most of the arthroplasty levels remained mobile, with similar rates of immobile discs in the NSAID and non-NSAID groups (13.2% and 22.7%, respectively; p = 0.318). Furthermore, there was a nonsignificantly lower rate of HO formation in the selective COX-2 group than the nonselective COX-2 group (30.8% vs 52.5%, respectively; p = 0.213). The clinical outcomes, including VAS neck, VAS arm, and NDI scores at 24 months postoperatively, were all similar in the NSAID and non-NSAID groups, as well as the selective and nonselective COX-2 groups (all p > 0.05).
In this study there was a trend toward less HO formation and fewer immobile discs in patients who used postoperative NSAIDs after cervical arthroplasty than those who did not, but this trend did not reach statistical significance. Patients who used selective COX-2 NSAIDs had nonsignificantly less HO than those who used nonselective COX-2 NSAIDs. The clinical outcomes were not affected by the use of NSAIDs or the kinds of NSAIDs used (selective vs nonselective COX-2). However, the study was limited by the number of patients included, and the efficacy of NSAIDs in the prevention of HO after cervical arthroplasty may need further investigation to confirm these results.