Tingkui Wu

Multilevel cervical disc replacement versus multilevel anterior discectomy and fusion: A meta-analysis

Background: Cervical disc replacement (CDR) has been developed as an alternative surgical procedure to anterior cervical discectomy and fusion (ACDF) for the treatment of single-level cervical degenerative disc disease. However, patients with multilevel cervical degenerative disc disease (MCDDD) are common in our clinic. Multilevel CDR is less established compared with multilevel ACDF. This study aims to compare the outcomes and evaluate safety and efficacy of CDR versus ACDF for the treatment of MCDDD. Methods: A meta-analysis was performed for articles published up until August 2016. Randomized controlled trials (RCTs) and prospective comparative studies associated with the use of CDR versus ACDF for the treatment of MCDDD were included in the current study. Two reviewers independently screened the articles and data following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Results: Seven studies with 702 enrolled patients suffering from MCDDD were retrieved. Patients who underwent CDR had similar operative times, blood loss, Neck Disability Index (NDI) scores, and Visual Analog Scale (VAS) scores compared to patients who underwent ACDF. Patients who underwent CDR had greater overall motion of the cervical spine and the operated levels than patients who underwent ACDF. Patients who underwent CDR also had lower rates of adjacent segment degeneration (ASD). The rate of adverse events was significantly lower in the CDR group. Conclusion: CDR may be a safe and effective surgical strategy for the treatment of MCDDD. However, there is insufficient evidence to draw a strong conclusion due to relatively low-quality evidence. Future long-term, multicenter, randomized, and controlled studies are needed to validate the safety and efficacy of multilevel CDR.

Clinical and radiographic features of hybrid surgery for the treatment of skip-level cervical degenerative disc disease: A minimum 24-month follow-up

We describe the radiographic changes of IS and investigate the safety and feasibility of hybrid surgery (HS) coupling cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for the treatment of skip-level cervical degenerative disc disease (CDDD). Twenty-seven patients who received HS were retrospectively reviewed. Clinical evaluation based on the Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) and Visual Analog Scale (VAS) scores. Radiographic parameters included cervical alignment (CA), functional spine unite (FSU) angle of intermediated segment (IS), range of motion (ROM) and intervertebral disc height (IDH). Data regarding radiographic changes at IS were collected. The mean follow-up duration of 30.10months. Compared with preoperative value, JOA, NDI and VAS scores significantly improved after surgery (p<0.05). The CA was recovered significantly after surgery (p<0.05). There was no significant difference in the FSU angle and the IDH of IS between before and at 24months postoperatively (p>0.05). The ROM of IS significantly decreased at the first week after surgery (p<0.05), was similar to preoperative value at 3months postoperatively and significantly increased after 6months (p<0.05). Radiographic changes at IS were observed in 2 patients and Class II Heterotopic ossification (HO) was detected in 2 patients. HS is a safe and feasible alternative procedure for the treatment of skip-level CDDD. It preserved the IS intact and achieved satisfactory clinical and radiographic outcomes over a 24-month follow-up.

Cervical disc arthroplasty for the treatment of adjacent segment disease: A systematic review of clinical evidence

The safety and efficacy of cervical disc arthroplasty (CDA) performed adjacent to previous fusion for the treatment of adjacent segment disease (ASD) remains unknown. This systematic review summarizes clinical evidence on the outcomes of CDA performed adjacent to previous cervical fusion. A systematic search of PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase for literature published through March 2017 was conducted. All the studies on CDA for the treatment of ASD after cervical fusion surgery were included. Two independent reviewers searched and assessed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). A total of 5 studies were identified. The overall quality of evidence was low. All included studies demonstrated that clinical outcomes reflected by several assessment scales improved after arthroplasty. Cervical lordosis range of motion (ROM) after arthroplasty remained and was even enhanced postoperatively. The rate of complications and subsequent surgeries was low. There is a dearth of information regarding the outcomes of CDA for the treatment of ASD in the literature. In general, CDA may be a safe and effective surgical procedure to treat ASD, but this conclusion needs to be confirmed by future long-term, prospective clinical trials.

Artificial cervical disc replacement with the Prestige-LP prosthesis for the treatment of non-contiguous 2-level cervical degenerative disc disease: A minimum 24-month follow-up

OBJECTIVE We describe the features of non-contiguous 2-level cervical degenerative disc disease (NCDDD), investigate the safety and feasibility of artificial cervical disc replacement (ACDR) for the treatment of NCDDD, and expect that our study will provide spine surgeons with an alternative procedure for NCDDD. METHODS Twenty-five patients with NCDDD received ACDR with a Prestige-LP prosthesis. Clinical outcomes were evaluated using the 36-Short Form (SF-36, Mental Component Summary [MCS] and Physical Component Summary [PCS]), Visual Analog Scale (VAS), Japanese Orthopedic Association (JOA), and Neck Disability Index (NDI) scores. Radiographic evaluations included cervical lordosis (CL), range of motion (ROM), and disc height (DH). Data regarding complications were collected as well. RESULTS The mean follow-up period was 32.24 months. Clinical outcomes, including SF-36 MCS and PCS, VAS, JOA, and NDI scores significantly improved at the 24-month follow-up (p<0.05). There were no significant differences in CL and ROM at the 24-month follow-up (p>0.05). Although there was a significant difference between the before and 3-month follow-up (p<0.05), the ROM of the intermediate segment (IS) showed a tendency of returning to the preoperative state. The DH of the IS was maintained at each measurement while the DH of the upper and lower operated segments significantly increased at the 24-month follow-up (p<0.05). One patient, whose prosthesis remained mobile at the last follow-up, showed evidence of heterotopic ossification (HO). CONCLUSION ACDR with the Prestige-LP prosthesis is a safe and feasible alternative procedure for treatment of NCDDD. In the future, a large-sample, prospective randomized controlled study with long-term follow-up will be needed to further demonstrate noncontiguous ACDR as an optimal surgical option for NCDDD.

In vitro biomechanical comparison after fixed- and mobile-core artificial cervical disc replacement versus fusion

Abstract In vitro biomechanical analysis after cervical disc replacement (CDR) with a novel artificial disc prosthesis (mobile core) was conducted and compared with the intact model, simulated fusion, and CDR with a fixed-core prosthesis. The purpose of this experimental study was to analyze the biomechanical changes after CDR with a novel prosthesis and the differences between fixed- and mobile-core prostheses. Six human cadaveric C2–C7 specimens were biomechanically tested sequentially in 4 different spinal models: intact specimens, simulated fusion, CDR with a fixed-core prosthesis (Discover, DePuy), and CDR with a mobile-core prosthesis (Pretic-I, Trauson). Moments up to 2 Nm with a 75 N follower load were applied in flexion–extension, left and right lateral bending, and left and right axial rotation. The total range of motion (ROM), segmental ROM, and adjacent intradiscal pressure (IDP) were calculated and analyzed in 4 different spinal models, as well as the differences between 2 disc prostheses. Compared with the intact specimens, the total ROM, segmental ROM, and IDP at the adjacent segments showed no significant difference after arthroplasty. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment (C5/6) and total ROM than CDR with a fixed-core prosthesis (P > .05). Besides, the difference in IDP at C4/5 after CDR with 2 prostheses was without statistical significance in all the directions of motion. However, the IDP at C6/7 after CDR with a mobile-core prosthesis was lower than CDR with a fixed-core prosthesis in flexion, extension, and lateral bending, with significant difference (P < .05), but not under axial rotation. CDR with a novel prosthesis was effective to maintain the ROM at the target segment and did not affect the ROM and IDP at the adjacent segments. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment and total ROM, but lower IDP at the inferior adjacent segment than CDR with a fixed-core prosthesis.

A comparison of anterior cervical discectomy and fusion combined with cervical disc arthroplasty and cervical disc arthroplasty for the treatment of skip-level cervical degenerative disc disease: A retrospective study

Abstract Anterior cervical discectomy and fusion (ACDF) has been widely performed for the treatment of multilevel cervical degenerative disc disease (CDDD). In recent decades, cervical disc arthroplasty (CDA) and hybrid surgery (HS) have been developed to overcome the shortcomings of ACDF. Controversy still remains with regard to the optimal surgical procedure for skip-level CDDD. A total of 55 patients who received surgical treatment for skip-level CDDD in our department were reviewed. The patients were divided into the HS group (n = 29) and the CDA group (n = 26). The collected data included Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analog Scale (VAS) scores, and cervical lordosis (CL), range of motion (ROM), and intervertebral disc height (IDH). Radiological changes at the intermediate segment (IS) were also collected. All data were collected preoperatively and at routine postoperative intervals of 1 week and 3, 6, and 12 months and at the last follow-up period. Compared with preoperative values, mean JOA, NDI, and VAS scores significantly improved after surgery in both the HS and CDA groups (P < .05). However, there were no significant differences between the groups (P > .05). The HS group had better CL recovery than the CDA group after surgery (P < .05). There was no significant difference in the ROM of C2–C7 between the 2 groups (P > .05). A significant difference in the ROM of the IS was found at the last follow-up between the 2 groups (P < .05). At the last-follow-up, 4 discs (14.29%) in the CDA group and 6 discs (19.36%) in the HS group had adjacent segment degeneration (ASD) without symptoms. Both HS and CDA might be considered safe and effective surgical strategies for the treatment of skip-level CDDD. Although the clinical outcomes were similar in the 2 groups, CDA altered the ROM of the IS to a lesser degree.

Intraoperative Anterior Migration of the Prestige-LP Cervical Disc Owing to an Inappropriate Implantation Sequence During Continuous 2-Level Artificial Cervical Disc Replacement: A Case Report with 8-Year Follow-Up

BACKGROUND Owing to its unique advantages, 2-level artificial cervical disc replacement (ACDR) is gaining attention. Among artificial discs designed for use in ACDR, the Food and Drug Administration-approved Prestige-LP Cervical Disc is widely used. There are no standard implantation sequences for 2-level ACDR using the Prestige-LP disc, and complications resulting from inappropriate implantation sequences remain unknown. CASE DESCRIPTION A 45-year-old woman underwent continuous 2-level ACDR using the Prestige-LP disc and experienced anterior migration of a previously inserted artificial disc after secondary disc implantation at an upper segment owing to an inappropriate implantation sequence during surgery. Intraoperative radiographs showed stable index levels and artificial discs. We tapped the migrated disc back into its correct position and recommended a postoperative functional exercise plan to the patient. We followed the patient for 8 years to verify the safety of our solution. We developed an implantation strategy for 2-level ACDR to avoid this complication in the future. CONCLUSIONS During 2-level ACDR, a top-down sequence should be used to implant prostheses. When anterior disc migration occurs, intraoperative radiographs should be obtained to ensure stability of the index levels. If there is no instability, the migrated tab can be tapped back into its correct position. In addition, limiting motion rather than allowing intermittent movement of the neck for at least 3 months is important to promote union between bone and prosthesis.

Is the behavior of disc replacement adjacent to fusion affected by the location of the fused level in hybrid surgery

BACKGROUND CONTEXT Hybrid surgery (HS), consisting of cervical disc arthroplasty (CDA) at the mobile level, along with anterior cervical discectomy and fusion at the spondylotic level, could be a promising treatment for patients with multilevel cervical degenerative disc disease (DDD). An advantage of this technique is that it uses an optimal procedure according to the status of each level. However, information is lacking regarding the influence of the relative location of the replacement and the fusion segment in vivo. PURPOSE We conducted the present study to investigate whether the location of the fusion affected the behavior of the disc replacement and adjacent segments in HS in vivo. STUDY DESIGN This is an observational study. PATIENT SAMPLE The numbers of patients in the arthroplasty-fusion (AF) and fusion-arthroplasty (FA) groups were 51 and 24, respectively. OUTCOME MEASURES The Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analog Scale (VAS) scores were evaluated. Global and segmental lordosis, the range of motion (ROM) of C2-C7, and the operated and adjacent segments were measured. Fusion rate and radiological changes at adjacent levels were observed. METHODS Between January 2010 and July 2016, 75 patients with cervical DDD at two contiguous levels undergoing a two-level HS were retrospectively reviewed. The patients were divided into AF and FA groups according to the locations of the disc replacement. Clinical outcomes were evaluated according to the JOA, NDI, and VAS scores. Radiological parameters, including global and segmental lordosis, the ROM of C2-C7, the operated and adjacent segments, and complications, were also evaluated. RESULTS Although the JOA, NDI, and VAS scores were improved in both the AF and the FA groups, no significant differences were found between the two groups at any follow-up point. Both groups maintained cervical lordosis, but no difference was found between the groups. Segmental lordosis at the fusion segment was significantly improved postoperatively (p<.001), whereas it was maintained at the arthroplasty segment. The ROM of C2-C7 was significantly decreased in both groups postoperatively (AF p=.001, FA p=.014), but no difference was found between the groups. The FA group exhibited a non-significant improvement in ROM at the arthroplasty segment. The ROM adjacent to the arthroplasty segment was increased, although not significantly, whereas the ROM adjacent to the fusion segment was significantly improved after surgery in both groups (p<.001). Fusion was achieved in all patients. No significant difference in complications was found between the groups. CONCLUSIONS In HS, cephalic or caudal fusion segments to the arthroplasty segment did not affect the clinical outcomes and the behavior of CDA. However, the ROM of adjacent segments was affected by the location of the fusion segment; segments adjacent to fusion segments had greater ROMs than segments adjacent to arthroplasty segments.

The impact of the difference in O-C2 angle in the development of dysphagia after occipitocervical fusion: a simulation study in normal volunteers combined with a case-control study

BACKGROUND CONTEXT Dysphagia has been recognized as one of the most serious complications after occipitocervical fusion (OCF), and the difference between postoperative and preoperative O-C2 angle (dO-C2A) was proposed to be an indicator in predicting and preventing dysphagia. Therefore, to prevent postoperative dysphagia, previous studies recommend that surgeons should correct the O-C2 angle (O-C2A) during surgery if the occipitocervical alignment was in an excessively flexed position. However, until now, there was no explicit indicator of the condition in which surgeons should adjust the patients O-C2A during surgery. PURPOSE One of the purposes of this study was to explore the threshold of dO-C2A between dysphagia and normal swallowing by a simulation study. The other aim was to evaluate the validity of the threshold of dO-C2A in predicting dysphagia after OCF via a case-control study. STUDY DESIGN This is a simulation study combined with a retrospective case-control study. PATIENT SAMPLE Thirty volunteers were enrolled in the simulation study. Thirty-four consecutive patients who underwent OCF between September 2011 and September 2016 were included in the case-control study. OUTCOME MEASURES The outcome measures included O-C2A, C2-7 angle (C2-7A), atlantodental interval (ADI), the narrowest oropharyngeal airway space (nPAS), the rate of change in dnPAS (%dnPAS), and the prevalence of postoperative dysphagia. MATERIALS AND METHODS In the simulation study, each volunteer received two lateral x-rays of their cervical spine in neutral position and dysphagia position, respectively. We compared the radiographic parameters in neutral and dysphagia positions. The cumulative frequency diagram of dO-C2A in the dysphagia position was analyzed to identify the threshold of dO-C2A in the development of dysphagia. In the case-control study, these 34 patients were divided into two groups according to the threshold of dO-C2A identified in the simulation study. The impact of radiographic parameters on nPAS was analyzed. The prevalence of postoperative dysphagia between the two groups was compared to evaluate the validity of the threshold of dO-C2A in predicting dysphagia after OCF. RESULTS In the simulation study, the mean O-C2A and nPAS in the dysphagia position were significantly smaller than in the neutral position (p<.05). There was no significant difference between the mean C2-7A in the neutral and dysphagia positions (p>.05). There was a significant positive correlation between dO-C2A and dnPAS (p<.05). A dO-C2A of -5° delineated the threshold between normal swallowing and dysphagia. In the case-control study, multiple regression analysis showed that dO-C2A was the only significant variable correlated with dnPAS (β=0.769, p<.001). Among the reviewed 34 patients, the incidence of dysphagia was 17.6% (6/34) at 2 weeks after surgery and decreased over time to 11.8% (4 of 34) at the last follow-up. There was also a significant positive correlation between the dO-C2A and dnPAS (p<.05). The prevalence of dysphagia after OCF in patients with dO-C2A<-5° was as high as 66.7% (6/9). However, there was no patient suffering from dysphagia in patients with dO-C2A≥-5°. CONCLUSION The present study showed that the dO-C2A should be a key factor in the development of postoperative dysphagia after OCF. A dO-C2A of -5° could be the threshold between dysphagia and normal swallowing. Furthermore, to avoid dysphagia, surgeons should correct the O-C2A just before the final occipitocervical fixation if the checked dO-C2A during surgery is less than -5°.

Pulled-out locking screw re-screwed spontaneously in anterior cervical decompression and fusion with the zero-profile implant system: A case report

Rationale: The zero-profile, standalone device (Zero-P, Synthes GmbH, Switzerland) has been reported to be an effective and safe treatment method with similar clinical outcomes compared with plate. Instrumental complications concerning Zero-P have been little reported. Considering the rarity, we present this amazing case to share with our spinal surgeons and instrument specialists. Patient Concerns: A 46-year-old man patient presented to our hospital with neck and shoulders pain for 23 years, numbness and weak-ness of right hand for 6 months. Diagnoses: Hypoesthesia in the right C6 and C7 roots distribution, myodynamia weakness of the right little finger was detected from physical examination. Two-level anterior cervical decompression and fusion (ACDF) using the Zero-P was performed via a classic right Smith–Robinson approach after induction of general anesthesia. Three months postoperative x-rays showed a good position of the implant. Six months postoperative x-rays showed a locking screw at the segment C6/7 pulled out. The patient was diagnosed as screw pullout after ACDF. Interventions: The patient was treated conservatively with regular follow-up as he was asymptomatic and no evidence of esophageal perforation was detected. Outcomes: The patient was followed again and 24 months postoperative x-rays also showed the pulled-out locking screw had re-screwed spontaneously. The patient was noticed that a revision surgery was needed if symptoms occur. At present bony union is not reached but he is still asymptomatic. Lessons: Pulled-out screws re-screwed spontaneously are rare but it does occur. Insertion angle may affect the stability of the Zero-P device, and the repeated micro-motion may be the critical reason of the screw pull-out and re-screwing. The management of screws pull-out after ACDF remains individualized and a revision surgery is not necessary for every patient. Conservative treatment such as orthosis and regular follow-ups may be suitable for some asymptomatic patients.