Effect of posterior subsidence on cervical alignment after anterior cervical corpectomy and reconstruction using titanium mesh cages in degenerative cervical disease

Subsidence after anterior cervical reconstruction using a titanium mesh cage (TMC) has been a matter of debate. The authors investigated and analyzed subsidence and its effect on clinical and radiologic parameters after cervical reconstruction using a TMC for degenerative cervical disease. Thirty consecutive patients with degenerative cervical spine disorders underwent anterior cervical corpectomy followed by reconstruction with TMC. Twenty-four patients underwent a single-level corpectomy, and six patients underwent a two-level corpectomy. Clinical outcomes were assessed using a Visual Analogue Scale (VAS), the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI). Fusion status, anterior and posterior subsidence of the TMC, segmental angle (SA) and cervical sagittal angle (CSA) were assessed by lateral and flexion-extension radiographs of the neck. The mean follow-up period was 27.6 months (range, 24 to 49 months). The VAS, NDI and JOA scores were all significantly improved at the last follow-up. No instances of radiolucency or motion-related pseudoarthrosis were detected on radiographic analysis, yielding a fusion rate of 100%. Subsidence occurred in 28 of 30 patients (93.3%). The average anterior subsidence of the cage was 1.4 ± 0.9 mm, and the average posterior subsidence was 2.9 ± 1.2 mm. The SA and CSA at the final follow-up were significantly increased toward a lordotic angle. Anterior cervical reconstruction using TMC and plating in patients with cervical degenerative disease provides good clinical and radiologic outcomes. Cage subsidence occurred frequently, especially at the posterior part of the cage. Despite the prominent posterior subsidence of the TMC, SA and CSA were improved on final follow-up radiographs, suggesting that posterior subsidence may contribute to cervical lordosis.     

Clinical experience using polyetheretherketone (PEEK) intervertebral structural cage for anterior cervical corpectomy and fusion

Anterior cervical corpectomy and fusion (ACCF) is commonly performed for various pathologies involving the cervical spine. Although polyetheretherketone (PEEK) cages have been widely used following anterior cervical discectomy and fusion (ACDF), clinical literature demonstrating its efficacy following ACCF is sparse. A retrospective review of patients enrolled in a prospective database who underwent single/multi-level ACCF was performed. Fifty-nine patients were identified who underwent corpectomy reconstruction with PEEK cages for symptomatic degenerative, neoplastic, infectious, or traumatic pathologies of the cervical spine. Thirty-five patients having at least 6 months follow-up (FU) were included in the final analysis. The mean age of patients was 51 years (range, 18–81 years) with FU ranging from 6 to 33 months (mean, 6.6 months). None of the patients had dysphagia at last FU. There was no implant failure with fusion occurring in all patients. While 57% of patients (20/35) remained stable with no progression of myelopathy, 43% (15/35) improved one (11 patients) or two (four patients) Nurick grades after surgery. The use of PEEK cages packed with autograft or allograft is safe and effective following anterior cervical corpectomy, demonstrating high fusion rates and good clinical results. This synthetic material obviates the morbidity associated with autograft harvest and possible infectious risks of allograft. The wide array of cage dimensions facilitates ease of use in patients of all sizes and appears safe for use in the typical pathologic conditions encountered in the cervical spine.     

Anterior decompression and hybrid reconstruction with titanium mesh cage plus plate and self-locking stand-alone cage for the treatment of three-level cervical spondylotic myelopathy

It has been reported that anterior cervical decompression has good clinical outcomes for the treatment of adjacent three-level cervical spondylotic myelopathy (CSM). However, the application of a long plate in the anterior cervical spine poses substantial risks of soft tissue damage. In this retrospective study, we aimed to analyze the clinical and radiological results of the hybrid construction with titanium mesh cage (TMC) plus plate and self-locking stand-alone cage for treatment of adjacent three-level CSM. A total of 28 consecutive patients with adjacent three-level CSM were treated by anterior decompression and hybrid reconstruction with TMC plus plate and self-locking stand-alone cage. Clinical outcomes, complications, fusion rate and time, cage subsidence and spinal curvature were assessed. The mean follow-up period was 22.8 months. The average operative time was 103 ± 18.5 min, and the average blood loss was 115 ± 13.3 mL. The JOA score and degree of spinal curvature were significantly increased at the final follow-up compared with preoperatively (P < 0.05). Twenty-seven cases finally achieved a solid fusion, and the average time to achieve a solid fusion was 6.2 months. Postoperative complications included one case of cerebrospinal fluid leakage (3.57%), one case of temporary sore throat (3.57%) and two cases of TMC subsidence (7.1%). No dysphagia and hoarseness were observed. Anterior decompression and hybrid reconstruction with TMC plus plate and self-locking stand-alone cage could be used safely and effectively for the treatment of adjacent three-level CSM. It could effectively restore cervical lordosis, reduce the complications related to long plate fixation, and lead to satisfactory outcomes.     

Pelvic parameters of sagittal balance in extreme lateral interbody fusion for degenerative lumbar disc disease

There is increasing interest in the use of pelvic indices to evaluate sagittal balance and predict outcomes in patients with spinal disease. Conventional posterior lumbar fusion techniques may adversely affect lumbar lordosis and spinal balance. Minimally invasive fusion of the lumbar spine is rapidly becoming a mainstay of treatment of lumbar degenerative disc disease. To our knowledge there are no studies evaluating the effect of extreme lateral interbody fusion (XLIF) on pelvic indices. Hence, our aim was to study the effect of XLIF on pelvic indices related to sagittal balance, and report the results of a prospective longitudinal clinical study and retrospective radiographic analyses of patients undergoing XLIF in a single centre between January 2009 and July 2011. Clinical outcomes are reported for 30 patients and the retrospective analyses of radiographic data is reported for 22 of these patients to assess global and segmental lumbar lordosis and pelvic indices. Effect of XLIF on the correction of scoliotic deformity was assessed in 15 patients in this series. A significant improvement was seen in the visual analogue scale score, the Oswestry Disability Index and the Short Form-36 at 2 months and 6 months (p < 0.0001). The mean pelvic index was 48.6° ± 11.9° (± standard deviation, SD) with corresponding mean sacral slopes and pelvic tilt of 32.0° ± 10.6° (SD) and 18.0° ± 9.5 (SD), respectively. XLIF did not significantly affect sacral slope or pelvic tilt (p > 0.2). Global lumbar lordosis was not affected by XLIF (p > 0.4). XLIF significantly increased segmental lumbar lordosis by 3.3° (p < 0.0001) and significantly decreased the scoliotic Cobb angle by 5.9° (p = 0.01). We found that XLIF improved scoliosis and segmental lordosis and was associated with significant clinical improvement in patients with lumbar degenerative disc disease. However, XLIF did not change overall lumbar lordosis or significantly alter pelvic indices associated with sagittal balance. Long-term follow-up with a larger cohort will be required to further evaluate the effects of XLIF on sagittal balance.     

A new zero-profile,stand-alone Fidji cervical cage for the treatment of the single and multilevel cervical degenerative disc disease

To investigate the clinical and radiological results of the new zero-profile, stand-alone Fidji cervical cage to treat single- and multiple-level cervical DDD, and evaluate the safety and efficiency. Between October 2011 and July 2014, 72 consecutive patients (41 males and 31 females; mean age 50.9 years [range, 33–68 years]) with cervical DDD who underwent surgery and were followed for more than 2 years were enrolled in this study (mean 31.1 months, range 24–47 months). The study compared clinical outcomes, radiologic parameters and complication rates. The SF-36, VAS, NDI, and JOA scores of all patients were improved significantly after surgery at any time point. (all p < 0.05). The C2–C7 Cobb angle and the disc height index (DHI) of all patients were improved significantly after surgery at any time point (all p < 0.05). From 3 months after surgery to final follow-up the DHI showed a significant reduction comparing 1 week after surgery (all p < 0.05). The fusion rates were 91.7% (66/72) and the radiologic mean fusion time was 9.9 months. Radiological evidence of adjacent segment degeneration (ASD) was observed in 4/41 patients (9.8%). Postoperative complications included epidural hematoma, hoarseness, dysphagia, axial neck pain, and subsidence. The zero-profile, stand-alone Fidji cervical cage for ACDF can be considered an effective, reliable and safe alternative procedure in the treatment of cervical DDD.     

Comparison of allograft and polyetheretherketone (PEEK) cage subsidence rates in anterior cervical discectomy and fusion (ACDF)

Structural allografts and PEEK cages are commonly used interbody fusion devices in ACDF. The subsidence rates of these two spacers have not yet been directly compared. The primary aim of this study was to compare the subsidence rate of allograft and PEEK cage in ACDF. The secondary aim was to determine if the presence of subsidence affects the clinical outcome. We reviewed 67 cases (117 levels) of ACDF with either structural allograft or PEEK cages. There were 85 levels (48 cases) with PEEK and 32 levels (19 cases) with allograft spacers. Anterior and posterior disc heights at each operative level were measured at immediate and 6 months post-op. Subsidence was defined as a decrease in anterior or posterior disc heights >2 mm. NDI of the subsidence (SG) and non-subsidence group (NSG) were recorded. Chi-square test was used to analyze subsidence rates. T-test was used to analyze clinical outcomes (α = 0.05). There was no statistically significant difference between subsidence rates of the PEEK (29%; 25/85) and allograft group (28%; 9/32) (p = 0.69). Overall mean subsidence was 2.3 ± 1.7 mm anteriorly and 2.6 ± 1.2 mm posteriorly. Mean NDI improvement was 11.7 (from 47.1 to 35.4; average follow-up: 12 mos) for the SG and 14.0 (from 45.8 to 31.8; average follow-up: 13 mos) for the NSG (p = 0.74). Subsidence rate does not seem to be affected by the use of either PEEK or allograft as spacers in ACDF. Furthermore, subsidence alone does not seem to be predictive of clinical outcomes of ACDF.     

Extreme lateral interbody fusion for the treatment of adult degenerative scoliosis

Extreme lateral interbody fusion (XLIF; NuVasive Inc., San Diego, CA, USA) is a minimally invasive lateral transpsoas approach to the thoracolumbar spine. Though the procedure is rapidly increasing in popularity, limited data is available regarding its use in deformity surgery. We aimed to evaluate radiographic correction using XLIF in adults with degenerative lumbar scoliosis. Thirty consecutive patients were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Plain radiographs were obtained on all patients preoperatively, postoperatively, and at most recent follow-up. Plain radiographic measurements of coronal Cobb angle, apical vertebral translation, segmental lordosis, global lordosis, disc height, neuroforaminal height and neuroforaminal width were made at each time point. CT scans were obtained for all patients 1 year after surgery to evaluate for fusion. There was significant improvement in multiple radiographic parameters from preoperative to postoperative. Cobb angle corrected 72.3%, apical vertebral translation corrected 59.7%, neuroforaminal height increased 80.3%, neuroforaminal width increased 7.4%, and disc height increased 116.7%. Segmental lordosis at L4–L5 increased 14.1% and global lordosis increased 11.5%. There was no significant loss of correction from postoperative to most recent follow-up. There was an 11.8% pseudoarthrosis rate at levels treated with XLIF. Complications included lateral incisional hernia (n = 1), rupture of anterior longitudinal ligament (n = 2), wound breakdown (n = 2), cardiac instability (n = 1), pedicle fracture (n = 1), and nonunion requiring revision (n = 1). XLIF significantly improves coronal plane deformity in patients with adult degenerative scoliosis. XLIF has the ability to correct sagittal plane deformity, although it is most effective at lower lumbar levels.     

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 30.10 months. 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 24 months 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 3 months postoperatively and significantly increased after 6 months (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 anterior hybrid technique with bi-level Bryan artificial disc replacement and adjacent segment fusion for cervical myelopathy over three consecutive segments

This study aimed to assess the preliminary clinical efficacy and feasibility of the hybrid technique for multilevel cervical myelopathy. Considering the many shortcomings of traditional treatment methods for multilevel cervical degenerative myelopathy, hybrid surgery (bi-level Bryan artificial disc [Medtronic Sofamor Danek, Memphis, TN, USA] replacement and anterior cervical discectomy and fusion) should be considered. Between March 2006 and November 2012, 108 patients (68 men and 40 women, average age 45 years) underwent hybrid surgery. Based on the Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), and Odom’s criteria, the clinical symptoms and neurological function before and after surgery were evaluated. Mean surgery duration was 90 minutes, with average blood loss of 30 mL. Mean follow-up duration was 36 months. At the final follow-up, the mean JOA (± standard deviation) scores were significantly higher compared with preoperative values (15.08 ± 1.47 versus 9.18 ± 1.22; P < 0.01); meanwhile, NDI values were markedly decreased (12.32 ± 1.03 versus 42.68 ± 1.83; P < 0.01). Using Odom’s criteria, the clinical outcomes were rated as excellent (76 patients), good (22 patients), fair (six patients), and poor (four patients). These findings indicate that the hybrid method provides an effective treatment for cervical myelopathy over three consecutive segments, ensuring a good clinical outcome.     

Distractive flexion injuries of the subaxial cervical spine treated with a posterior procedure using cervical pedicle screws or a combined anterior and posterior procedure

The purpose of this study was to compare the clinical and radiographic outcomes of patients with distractive flexion (DF) injuries of the subaxial cervical spine who had undergone a posterior procedure using cervical pedicle screw (CPS) fixation with those who had undergone a combined anterior and posterior procedure. Recommendations for the surgical treatment of DF injuries of the subaxial cervical spine remain controversial. There are few clinical reports of posterior CPS fixation for DF injuries. We retrospectively reviewed the clinical records and radiographs of 50 consecutive patients with DF injuries of the subaxial cervical spine treated at the Imakiire General Hospital. Group 1 consisted of 24 patients who underwent posterior wiring fixation and fusion with additional anterior decompression and fusion. Group 2 consisted of 26 patients who underwent posterior decompression and fusion with CPS fixation. Group 1 had a significantly longer operation time (295.4 minutes) than Group 2 (163.3 minutes). Group 1 had significantly higher blood loss (689.1 g) than Group 2 (313.7 g). No patient in Group 1 or 2 developed postoperative neurological worsening. The mean loss of kyphotic correction was 1.6° and 0.1° in Groups 1 and 2, respectively, and the loss of kyphotic correction in Group 2 was significantly less than that of Group 1. We suggest that posterior procedures with CPS fixation are reasonable for the management of cervical DF injuries.     

Difference in canal encroachment by the fusion mass between anterior cervical discectomy and fusion with bone autograft and anterior plating,and stand-alone cage

We conducted a prospective randomized study comparing stand-alone cage and bone autograft and plate implants in anterior cervical discectomy and fusion (www.clinicaltrials.gov, NCT01011569). Our interim analysis showed autologous bone graft with plating was superior to a stand-alone cage for segmental lordosis. During this analysis, we noted a difference in canal encroachment by the fusion mass between the two fusion groups. A narrow cervical spinal canal is an important factor in the development of cervical spondylotic myelopathy, therefore this unexpected potential risk of spinal cord compression necessitated another interim analysis to investigate whether there was a difference in canal encroachment by the fusion mass between the two groups. Patients had a minimum 1 year of follow-up. The Neck Disability Index, neck and arm pain Visual Analog Scales and lateral radiographs, including bone fusion patterns, were evaluated. Twenty-seven (16 males, 11 females, mean age 54.8 years) and 31 (24 males, seven females, mean age 54.5 years) patients were in the cage and plate group, respectively. Both groups improved after surgery. Fusion began at 2.6 months and 1.3 months and finished at 6.7 months and 4.0 months in 24 (88.9%) and 28 (90.3%) patients in the cage and plate group, respectively. Encroachment into the spinal canal by the fusion mass was significantly different between the fusion types, occuring in 21 (77.8%) patients in the cage group versus six (19.4%) in the plate group (p = 0.003). There was a high incidence of spinal canal encroachment by the fusion mass in the stand-alone cage group, possibly limiting use in narrow spinal canals.     

Multivariable analysis of factors affecting length of stay and hospital charges after single-level corpectomy

Anterior cervical corpectomy and fusion (ACCF) is commonly employed for treating myelopathy, deformity, and a variety of other cervical pathologies. Limited data are available on factors associated with longer hospitalization and higher hospital charges following ACCF. The purpose of this study was to evaluate the pre-, intra-, and postoperative variables that are associated with length of hospital stay and hospital charges for patients undergoing single-level anterior cervical corpectomy and fusion in a retrospective case series. We retrospectively identified from a clinical database 69 patients who underwent single-level ACCF at a single institution from 2010 through 2014. Demographic variables, clinical information, and intraoperative data were analyzed with respect to length of hospitalization and hospital charges. T-test and Chi-squared testing as well as univariate and multivariable analysis were performed with p < 0.05 considered significant. On multivariable analysis, polytrauma, postoperative complications, lower postoperative hematocrit, and two-staged procedures were significantly associated with longer lengths of stay. Length of stay, postoperative complications, and two-staged procedures were significantly associated with higher hospital charges. Patients undergoing a two-staged procedure and those having postoperative complications experience a longer postoperative length of stay and incur higher hospital charges. Avoidance of postoperative anemia may help to reduce length of stay following ACCF.     

Preliminary comparison of radiolucent cages containing either autogenous cancellous bone or hydroxyapatite graft in multilevel cervical fusion

We compared the preliminary outcomes of cervical fusion performed using radiolucent cages containing either cancellous bone or hydroxyapatite graft. From July 2004 to June 2006, 45 consecutive patients presented with a total of 109 levels of degenerative disc disease between the C2 and C7 levels. Each patient underwent anterior cervical discectomy and fusion (ACDF) for each affected cervical disc. The retrospective analysis of the cage fillers was divided into group 1 (23 patients with 56 affected cervical levels) who received cages packed with cancellous bone marrow, and group 2 (22 patients with 53 affected cervical levels) who received cages packed with hydroxyapatite graft. Bone marrow was harvested from the anterior iliac crest. The Prolo scale was used to assess both the economic and functional status postoperatively. The Yates’ correction to test independence in a contingency was used to compare the fusion rate of both groups post-operatively at day 1 and at 1, 3 and 6 month follow-up. At a mean follow-up of 12 months, the fusion rates observed in groups 1 and 2, respectively, were 21.4% and 13.2% after 1 month, 76.8% and 64.2% after 3 months, and 98.2% and 96.2% after 6 months. Functional and economic status were better in group 2, with a statistical significance (p < 0.05) observed at the 3-month follow-up. Although hydroxyapatite graft is an osteoconductive, rather than osteoinductive, material, when used as a cage filler it is a safe and efficient substitute for cancellous bone.     

Anterior cervical discectomy plus intervertebral polyetheretherketone cage fusion over three and four levels without plating is safe and effective long-term

Anterior cervical discectomy and fusion (ACDF) is an established treatment for single-level cervical spondylotic myelopathy and radiculopathy, yet its stand-alone use for multi-level disease of the subaxial cervical spine remains controversial. We report a prospectively studied case series of 30 patients receiving polyetheretherketone (PEEK) cage fusion over three and four cervical levels without anterior plating. Seven (23.3%) four-level procedures (all C3 to C7) were performed, the other 23 (76.7%) being three-level, with 19 (64.4%) at C4 to C7 and four (12.3%) at C3 to C6. Long-term follow-up of more than 2 years was available in 67% of patients. This cohort showed statistically significant improvements in visual analogue score for neck pain (p = 0.0006), arm pain (p = 0.0003) and Japanese Orthopaedic Association myelopathy score (p = 0.002). Fused segment heights increased by 0.6–1.1%. Adjacent segment disease requiring ACDF at C3–4 was seen in 6.7% of patients (one after trauma) at a mean follow-up of 62 months. Same segment recurrence requiring posterior decompression with instrumented fusion was found in 10% of patients at a mean follow-up of 49 months, only one of whom had radiological evidence of cage subsidence. The results suggest the procedure is safe and effective with potentially less morbidity than anterior plating, shorter inpatient stays than posterior approaches, acceptable same segment recurrence and lower than predicted adjacent segment disease rates.     

Successful anterior fusion following posterior cervical fusion for revision of anterior cervical discectomy and fusion pseudarthrosis

Pseudarthrosis occurs after approximately 2–20% of anterior cervical discectomy and fusion (ACDF) procedures; it is unclear if posterior or anterior revision should be pursued. In this study, we retrospectively evaluate the outcomes in 22 patients with pseudarthrosis following ACDF and revision via posterior cervical fusion (PCF). Baseline demographics, preoperative symptoms, operative data, time to fusion failure, symptoms of pseudarthrosis, and revision method were assessed. Fusion outcome and clinical outcome were determined at last follow-up (LFU). Thirteen females (59%) and 9 (41%) males experienced pseudarthrosis at a median of 11 (range: 3–151) months after ACDF. Median age at index surgery was 51 (range: 33–67) years. All patients with pseudarthrosis presented with progressive neck pain, with median visual analog scale (VAS) score of 8 (range: 0–10), and/or myeloradiculopathy. Patients with pseudarthrosis <12 months compared to >12 months after index surgery were older (p = 0.013), had more frequent preoperative neurological deficits (p = 0.064), and lower baseline VAS scores (p = 0.006). Fusion was successful after PCF in all patients, with median time to fusion of 10 (range: 2–14) months. Eighteen patients fused both anteriorly and posteriorly, two patients fused anteriorly only, and two patients fused posteriorly only. Median VAS neck score at LFU significantly improved from the time of pseudarthrosis (p = 0.012). While uncommon, pseudarthrosis may occur after ACDF. All patients achieved successful fusion after subsequent posterior cervical fusion, with 91% fusing a previous anterior pseudarthrosis after posterior stabilization. Neck pain significantly improved by LFU in the majority of patients in this study.     

Bryan cervical disc prostheses: preservation of function over time

Preserving the function of cervical disc prostheses, even over the short term, is a matter of concern among surgeons. Our case series highlights our results and protocol for increasing the probability of continued device function. Twenty-five consecutive patients with a mean (±SEM) age of 44.3 ± 8.3 years underwent 29 cervical total disc arthroplasties for disc herniations. Three patients underwent primary bilevel arthroplasty, and one patient underwent a second arthroplasty for another herniation 2 years after the first. Prosthesis ranges of motion were measured using dynamic plain X-ray studies and compared to the ranges of motion of adjacent segments. At follow-up, all prostheses were in the correct location and without subsidence. All displayed firm secondary stability. One segment had fused. Twenty-eight of 29 devices were mobile an average of 9.5° ± 4.7° (range 3° to 20°) (for all 29 devices the average movement angle was 9.2° ± 5°; range 0° to 20°), 25 upper adjacent segments were mobile an average of 10.9° ± 4.5° (range 2° to 20°) (excluding the fused prosthesis: 11° ± 4.6°) and 15 lower adjacent segments were mobile an average of 9.8° ± 6° (range 1° to 21°). With our protocol, 28 of 29 cervical disc prostheses in 25 consecutive patients were mobile after an average of 22.3 ± 9.4 months. Prosthesis motion was physiological and very similar to that of the healthy adjacent segments. Long-term studies including larger numbers of patients are required to validate our initial observations.     

Comparison of anterior cervical discectomy and fusion with the zero-profile device versus plate and cage in treating cervical degenerative disc disease: A meta-analysis

Zero-profile device was applied to diminish the irritation of the esophagus in the treatment of cervical degenerative disc disease. However, the clinical application of the zero-profile device has not been testified with clinical evidence. The aim of the meta-analysis was to systematically compare the safety and effectiveness of anterior cervical discectomy and fusion with zero-profile device with plate and cage for the treatment of cervical degenerative disc disease. Electronic searches of PubMed and Embase were conducted up to May 2015. Relevant studies were included. Weighted mean difference (WMD) and 95% confidence intervals (CI) were assessed for continuous data. Risk ratio (RR) and 95% CI were assessed for dichotomous data. P value <0.05 was considered to be significant. Eleven studies were included in the meta-analysis. Compared with plate and cage, zero-p is associated with lower operation time of two-level surgery, less intraoperative blood loss, higher subsidence rate, higher JOA score, lower incidence of dysphagia in short-term (RR: 0.72, 95% CI [0.58, 0.90], P = 0.005, I² = 22%) and long-term (RR: 0.12, 95% CI [0.05, 0.30], P < 0.00001, I² = 0%) and lower Cobb angle of multilevel surgery (WMD: −3.16, 95% CI: [−4.35, −1.97], P < 0.00001, I² = 0%). No significant difference was found in one-level and two-level Cobb angle, fusion rate and operation time of one-level and three-level surgery. Both zero-p implantation and the plate and cage have respective advantages and disadvantages.     

Risk factors for the development of adjacent segment disease following anterior cervical arthrodesis for degenerative cervical disease: Comparison between fusion methods

This study aimed to determine the risk factors for developing adjacent segment disease (ASDz) after anterior cervical arthrodesis for the treatment of degenerative cervical disease by analyzing patients treated with various fusion methods. We enrolled 242 patients who had undergone anterior cervical fusion for degenerative cervical disease, and had at least 5 years of follow-up. We evaluated the development of ASDz and the rate of revision surgery. To identify the risk factors for ASDz, the sagittal alignment, spinal canal diameter, range of motion of the cervical spine, number of fusion segments, and fusion methods were evaluated. The patients were divided into three groups according to the fusion method: Group A contained patients who had received autogenous bone graft only (53 patients), Group B contained patients who received autogenous bone graft and plate augmentation (62 patients), and Group C contained patients who underwent cage and plate augmentation (127 patients). ASDz occurred in 33 patients, of whom 19 required additional surgery. The risk of developing ASDz was significantly higher in male patients (p = 0.043), patients whose range of motion of the cervical spine was >30° (p = 0.027), and patients with spinal canal stenosis (p = 0.010). The rate of development of ASDz was not different depending on the number of fusion segments. The rate of development of ASDz was 41.5% in Group A, 9.6% in Group B, and 5.51% in Group C (p = 0.03). In patients who underwent anterior cervical arthrodesis for degenerative disease, the occurrence of ASDz was related to age, the cervical spine range of motion, and spinal canal stenosis. Additional plate augmentation for anterior cervical arthrodesis surgery can lower the rate of ASDz development.     

Cervical artificial disc replacement with ProDisc-C: Clinical and radiographic outcomes with long-term follow-up

Cervical artificial disc replacement (ADR) is indicated for the treatment of severe radiculopathy permitting neural decompression and maintenance of motion. We evaluated the clinical and radiographic outcomes in cervical ADR patients using the ProDisc-C device (DePuy Synthes, West Chester, PA, USA) with a 5–9 year follow-up. Data were collected through a prospective registry, with retrospective analysis performed on 24 consecutive patients treated with cervical ADR by a single surgeon. All patients underwent single- or two-level ADR with the ProDisc-C device. Outcome measures included neck and arm pain (visual analogue scale), disability (neck disability index [NDI]), complications and secondary surgery rates. Flexion-extension cervical radiographs were performed to assess range of motion (ROM) of the device and adjacent segment disease (ASD). Average follow-up was 7.7 years. Neck and arm pain improved 60% and 79%, respectively, and NDI had an improvement of 58%. There were no episodes of device migration or subsidence. Mean ROM of the device was 6.4°. Heterotopic ossification was present in seven patients (37%). Radiographic ASD below the device developed in four patients (21%) (one single-level and three two-level ADR). No patient required secondary surgery (repeat operations at the index level or adjacent levels). Fourteen out of 19 patients (74%) were able to return to employment, with a median return to work time of 1.3 months. The ProDisc-C device for cervical ADR is a safe option for patients providing excellent clinical outcomes, satisfactory return to work rates and maintenance of segmental motion despite radiographic evidence of heterotopic ossification and ASD on long-term follow-up.     

Posterolateral lumbar fusion versus transforaminal lumbar interbody fusion for the treatment of degenerative lumbar scoliosis

This study compares the safety and efficacy of posterolateral lumbar fusion (PLF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of degenerative lumbar scoliosis (DLS). Forty DLS patients with Cobb angles of 20–60 degrees were randomized into either the PLF or TLIF treatment group, and were followed up for 2–5 years. Operating time, intraoperative blood loss, clinical outcomes, complications and imaging were compared between the two groups. There were significant differences between the PLF and TLIF treatment groups in operative time (187.8 ± 63.5 minutes and 253.2 ± 57.6 minutes, respectively; p = 0.002) and intraoperative blood loss (1166.7 ± 554.1 mL and 1673.7 ± 922.4 mL, respectively; p = 0.048). The occurrence rates of early complications in the two groups were 11.1% and 26.3%. The recovery rates of the lumbar lordotic angle and spinal sagittal balance were significantly different (36.7% versus 62.5% and 44.8% versus 64.1%, respectively). In various domains of the Scoliosis Research Society-22 (SRS-22) questionnaire, the scores for pain and satisfaction with the treatment showed significant differences between PLF and TLIF group (p = 0.033 and p = 0.006, for pain and satisfaction respectively), and the TLIF group showed better outcomes than the PLF group. There were no significant differences in the recovery rates in the Cobb angle and the spinal coronal balance, function, self-image, or mental health scores. Although TLIF increases the surgical trauma and occurrence of complications, it helps to improve lumbar lordosis and sagittal balance and shows better clinical outcomes. For patients without significant loss of lumbar lordosis and with good spinal sagittal balance preoperatively, PLF is still an option.