Comparison of biomechanical performance of single-level triangular and quadrilateral profile anterior cervical plates

The quadrilateral anterior cervical plate (ACP) is used extensively in anterior cervical discectomy and fusion (ACDF) to reconstruct the stability of the cervical spine and prevent cage subsidence. However, there have been no comparison studies on the biomechanical performance of quadrilateral ACP and triangular ACP. The objective of this study is to investigate the functional outcomes of quadrilateral ACP and triangular ACP usage in ACDF surgery. In this study, a finite element model of intact C1-C7 segments was established and verified. Additionally, two implant systems were built; one using triangle anterior cervical plates (TACP) and another using quadrilateral orion anterior cervical plate (QACP). Both models were then compared in terms of their postoperative biomechanical performance, under normal and excessive motion. Compared to QACP, the peak stress of the TACP screws and plates occurred at 359.2 MPa and 97.2 MPa respectively and were the highest during over extension exercises. Alternately, compared to TACP, the endplate peak stress and the cage displacement of QACP were the largest at over extension, with values of 7.5 MPa and 1.2 mm, respectively. Finally, the average stress ratio of bone grafts in TACP was relatively high at 31.6%. In terms of biomechanical performance, TACP can share the load more flexibly and reduce the risks of cage subsidence and slippage but the screws have high peak stress value, thereby increasing the risk of screw slippage and fracture. This disadvantage must be considered when designing a TACP based implant for a potential patient.

Covering of Plate after Anterior Cervical Fusion in Patients with Complete Spinal Cord Injury to Prevent Esophageal Injury: Technical Note

Background Esophageal injury after anterior corpectomy and fusion is a rare but life-threatening complication. It may cause mediastinitis due to anatomical continuity between the retropharyngeal space and the mediastinum, with reported high mortality rates. The acute and subacute injuries are most commonly of iatrogenic origin, while late perforation has been described several weeks to years later as a result of continuous friction or pressure of the instruments against the posterior wall of the esophagus, leading to ischemia and necrosis. This phenomenon is more common among quadriplegic patients who have undergone corpectomy and insertion of expandable or mesh cages and plate probably due to chronic erosion by hardware at the supine position. Methods Since 2015, we have applied the technique of using a patch of autologous fascia lata to cover the anterior cervical plate by suturing to the longus colli muscles in 58 quadriplegic patients; the mean follow-up was 35.2 (28–41) months. Results Since we started using this procedure, based on our follow-up at our center, there have been no cases of late esophageal perforation among quadriplegic patients. Conclusion As a technical note, it seems like this method would be able to reduce the prevalence of esophagus injury among quadriplegic patients. However, to substantiate the efficacy of this technique, long-term follow-up and larger sample size are needed because esophageal injury occurs rarely.

Comparative study of anterior cervical discectomy and fusion by anterior cervical plate and stand-alone cervical cage

<p class="abstract"><strong>Background:</strong> Anterior cervical discectomy (ACD) was used for management of degenerative cervical disc disorders (DCDD) in previous days. Further research and developments in management of DCDD led to evolution of standard and widely used operative technique as anterior cervical discectomy and fusion (ACDF) by either anterior cervical plate (ACDF-ACP) with bone grafting or stand-alone cage (ACDF-SAC). There is less data available in literature regarding when and where to use ACDF-ACP and ACDF-SAC.</p><p class="abstract"><strong>Methods:</strong> The study was conducted on 20 patients operated in Government Medical College and Hospital and Pacific Hospital and Research Centre, Aurangabad from June 2018 to March 2020. These patients divided into group A - 10 patients, operated by ACDF-SAC which are further divided as group Aa - 6 patients - operated for single level ACDF-SAC and group Ab - 4 patients - operated for two level ACDF-SAC, group B - 10 patients, operated by ACDF-ACP which are further divided as group Ba - 5 patients - operated for single level ACDF-ACP and group Bb - 5 patients - operated for two level ACDF-ACP. Patients evaluated preoperatively and postoperatively using X-ray cervical spine anteroposterior (AP) and lateral views, MRI cervical spine, visual analogue scale (VAS) for pain, Robinson’s criteria and Cobb’s angle.<strong></strong></p><p class="abstract"><strong>Results:</strong> In our study we found, ACDF-SAC has small incision size, less intraoperative time, easy to carry out for surgeons, less intraoperative complications and better clinical outcome as compared to ACDF-ACP. Whereas only radiological results were better in ACDF-ACP than ACDF-SAC.</p><p class="abstract"><strong>Conclusions:</strong> ACDF-SAC is superior to ACDF-ACP for appropriately selected patients and in well experienced hands.</p>

Effectiveness comparison of Zero-profile interbody fusion implant and anterior cervical plate interbody fusion device: a clinical and radiological study

Background Anterior cervical discectomy and fusion (ACDF) is a successful strategy to relieve the symptoms caused by cervical degenerative disease. Postoperative dysphagia is one complication of this kind of surgery. We performed this study to compare the clinical outcomes, radiographic parameters, and complications of ACDF with a Zero-profile implant (Zero-P) and titanium plate and cage.Methods There were 68 patients received ACDF of single level, 35 patients with Zero-profile implant (Zero-p group) and 33 patients with traditional plate and cage (Cage group), from C3–C7 during 2014 to 2016. Collecting and analyzing of clinical and radiological data were performed. Patients were followed-up at least 1 year after surgery. The operation time, blood loss, Japan Department of Orthopedics Association (JOA) score, pain Visual Analogue Score (VAS), Neck Disability Index (NDI) score and dysphagia score were recorded. Additionally, changes in cervical lordosis, fusion rate and adjacent segment degeneration were analyzed as well.Results For neurologic outcomes, the JOA, VAS and NDI were statistically equivalent between the two groups (P>0.05). For radiographic outcomes, there were no significant differences in the C2-7 Cobb angles, segmental Cobb angle and incidence of subsidence at the final follow-up (P>0.05). No degenerative changes was found in the Zero-p group, whereas 5 patients in the Cage group developed degeneration in adjacent segments (P<0.05). Also, the incidence of postoperative dysphagia is higher in Cage group than in Zero-p group at 3 months and 12 months (P<0.05).Conclusions Both Zero-profile implant and anterior cervical plate interbody fusion device were demonstrated to be effective and safe strategies in this study. Considering the lower incidences of dysphagia and degenerative changes, the Zero-profile implant is a good succedaneum.