Comparison of the long-term efficacy of two-level cervical artificial disc replacement and anterior cervical decompression and fusion / 中华骨科杂志

Objective:To compare the long-term efficacy of two-level cervical artificial disc replacement (CADR) and anterior cervical decompression and fusion (ACDF) in the treatment of cervical degenerative diseases.Methods:A retrospective analysis was performed on patients who had received two-level anterior cervical surgery for cervical degenerative diseases for more than 15 years from December 2003 to December 2007. The patients were divided into two groups: CADR and ACDF according to surgical methods. There were 15 patients in the CADR group, including 7 males and 8 females, with an average age of 49.73±10.26 (range, 32-70) years. Three cases of mixed cervical spondylosis, 5 cases of cervical spondylotic radiculopathy, 7 cases of cervical spondylotic myelopathy, including C 3, 4 and C 4, 5 level 1 case, C 3, 4 and C 5, 6 level 2 cases, C 4, 5 and C 5, 6 level 7 cases, C 5, 6 and C 6, 7 level 5 cases, operative segment range of motion (ROM) was 9.10°±4.00°. The follow-up time in the CADR group was 189.07±13.51 (range, 162-210) months. There were 20 patients in the ACDF group, including 12 males and 8 females, with an average age of 52.60±8.83 (range, 32-68) years. Two cases of mixed cervical spondylosis, 3 cases of cervical spondylotic radiculopathy, 15 cases of cervical spondylotic myelopathy, including C 3, 4 and C 4, 5 level 1 case, C 4, 5 and C 5, 6 level 15 cases, C 5, 6 and C 6, 7 level 4 cases, the ROM of the surgical segment was 8.31±5.23°. The mean follow-up time of ACDF group was 184.20±21.39 (range, 156-222) months. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were evaluated preoperatively and at the last follow-up. The overall ROM of the cervical spine, ROM of the surgical segment, and Miyazaki grading of the adjacent intervertebral disc, Odom score and complications of the two groups were evaluated at the last follow-up. Results:In the CADR group, the JOA score improved from 13.20±2.64 preoperatively to 15.93±1.22 at last follow-up, and NDI improved from 27.60%±6.44% preoperatively to 15.07%±9.71% at last follow-up, JOA improvement rate was 59.44%±60.86%, and NDI decreased by 12.53%±9.64%. In the ACDF group, JOA score improved from 12.93±2.46 preoperatively to 15.65±1.25 at last follow-up, NDI improved from 30.80%±8.11% preoperatively to 12.80%±6.31% at last follow-up, JOA improvement rate was 60.51%±43.17%, NDI decreased by 18.00%±8.34%. There was no significant difference in JOA and NDI between the two groups before surgery and at the last follow-up. At the last follow-up, the overall ROM of the cervical spine in the CADR group was 38.33°±12.31°, the ROM of the surgical segment was 6.51°±4.61°, and the overall ROM of the cervical spine in the ACDF group was 31.11°±8.65°, the ROM of the surgical segment was 0°. There was a significant difference in the overall ROM of the cervical spine between the two groups at the last follow-up ( t=7.22, P=0.049). The incidence of increased Miyazaki grading of the upper and lower adjacent segment of the cervical intervertebral disc in the CADR group were 40% and 47%, and the rate of new intervertebral disc herniation were 20% and 13%. The incidence of increased Miyazaki grading of the upper and lower adjacent segment of the cervical intervertebral disc in the ACDF group were 45% and 50%, and the incidence of new herniated disc were 25% and 40%, there is a significant difference in the degeneration rate of the lower adjacent segments between the two groups (χ 2=4.38, P=0.036). At the last follow-up, the excellent and good rate of Odom in the CADR group was 80%, and 1 case was revised; the excellent and good rate of Odom in the ACDF group was 85%, and 1 case was revised. There was no significant difference in the overall efficacy between the two groups. Conclusion:The long-term clinical efficacy of two-level CADR is comparable to that of traditional ACDF, and it preserved the ROM of the surgical segment, and is superior to ACDF in terms of the overall cervical spine ROM, and the incidence of adjacent segment degeneration.

Results of Total Cervical Disc Replacement with a Minimum Follow-up of 10 Years / Resultados da artroplastia total de disco cervical com acompanhamento mínimo de 10 anos

Abstract Objective In the present study, we present the results with at least 10 years of follow-up of the cervical disc prosthesis implanted in a single level. Methods Retrospective study of patients undergoing single-level total cervical disc replacement (TCDR). Clinical results included the neck disability index (NDI) and the visual analogue scale (VAS) in the preoperative period, one year postoperatively, and a minimum of 10 years of follow-up. The radiographic parameters included cervical mobility, segmental lordosis, C2-C7 angle, heterotopic ossification (HO), facet and joint degeneration (FJD) and adjacent segment disease (ASD). Results We identified 22 patients, 16 women and 6 men with mean age of 39.7 years old (26-51 years old), of which fifteen completed a minimum follow-up of 10 years. There was a statistically significant improvement of NDI and VAS (p < 0.001) between the preoperative and the postoperative periods (1 year or > 10 years). At the end of 10 years, HO was observed in 59% of the cases. The mobility of the implant was preserved in 80% of the patients. Radiological evidence of ASD was recorded in 6 patients (40%). There was no correlation between the clinical parameters evaluated and the presence of ASD or the different classes of HO. Conclusion Clinical improvement in all evaluated parameters, which persists over time. Most implants maintained mobility, as has already been demonstrated in other studies with shorter follow-ups. In a significant percentage of cases, ASD was observed, questioning the concept of motion preserving technology. However, we did not have any surgical intervention for this reason, since there was no correlation with worse clinical results.

Resumo Objetivo No presente estudo, apresentamos os resultados com um acompanhamento mínimo de 10 anos da artroplastia total do disco cervical (ATDC) em um nível. Métodos Estudo retrospectivo de pacientes submetidos a ATDC em um nível. Os resultados clínicos incluíram o índice de incapacidade relacionada ao pescoço (IIRP) e a escala visual analógica (EVA) no período pré-operatório, um ano pós-operatório e um mínimo de 10 anos de acompanhamento. Os parâmetros radiográficos incluíram a mobilidade cervical, lordose segmentar, ângulo C2-C7, ossificação heterotópica (OH), degeneração facetária e articular (DFA) e doença do segmento adjacente (DSA). Resultados Identificados 22 pacientes, 16 mulheres e 6 homens com média de idade de 39,7 anos (26-51 anos), dos quais 15 tiveram um acompanhamento mínimo de 10 anos. Foi verificada melhoria estatisticamente significativa do IIRP e EVA (p < 0,001) entre pré-operatório e pós-operatório. (1 ano ou > 10 anos). Ao final de 10 anos, OH foi observada em 59% dos casos. A mobilidade do implante foi preservada em 80% dos pacientes. Houve evidência radiológica de DSA em 6 pacientes (40%). Não houve correlação entre os parâmetros clínicos avaliados e a presença de DSA ou as diferentes classes de OH. Conclusão Melhoria clínica em todos os parâmetros avaliados, que persiste ao longo do tempo. A maioria dos implantes manteve a mobilidade, como já demonstrado em estudos anteriores com acompanhamentos mais curtos. Numa percentagem significativa, a DSA estava presente, questionando o conceito da tecnologia de preservação de movimento. No entanto, sem nenhuma intervenção cirúrgica por esse motivo, uma vez que não houve correlação com piores resultados clínicos.

A network meta-analysis of different surgical methods in the treatment of lumbar disc herniation / 中国组织工程研究

BACKGROUND: At present, there are many surgical methods for the treatment of lumbar disc herniation, and the therapeutic effects have their own advantages. Although there are many meta-analyses to compare the therapeutic effects of the two surgical methods, there is no comparison of the therapeutic effects of several surgical methods. OBJECTIVE: To compare the differences of different surgical methods in the treatment of lumbar disc herniation by network meta-analysis. METHODS: PubMed, Embase, Cochrane Library, Ovid and CNKI were searched, and randomized controlled trials or retrospective studies on different surgical methods for the treatment of lumbar disc herniation were collected. According to the inclusion and exclusion criteria established in advance, the quality of included randomized controlled trials was evaluated, and the data were analyzed by STATA 15.0 software. RESULTS AND CONCLUSION: A total of 42 studies, 5 156 patients and 9 surgical treatments were included. Surgical treatments contain total disc replacement, lumbar disc fusion, standard open discectomy, microendoscopic discectomy, microdiscectomy, percutaneous endoscopic lumbar discectomy, chemonucleolysis, automatic percutaneous lumbar discectomy and percutaneous laser disc decompression. The results of network meta-analysis showed that(from best to worst):(1) There was no significant difference in leg pain relief, and the rank probability was percutaneous laser disc decompression > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > microdiscectomy > lumbar disc fusion > total disc replacement.(2) There was no significant difference in low back pain relief, and the rank probability was total disc replacement > lumbar disc fusion > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > microdiscectomy > percutaneous laser disc decompression > standard open discectomy.(3) There was no significant difference in Oswestry disability index scores, and the rank probability was microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > microdiscectomy > total disc replacement > lumbar disc fusion.(4) There were some statistical differences in the success rate, and the rank probability was total disc replacement > lumbar disc fusion > microendoscopic discectomy > percutaneous endoscopic lumbar discectomy > standard open discectomy > percutaneous laser disc decompression > microdiscectomy > chemonucleolysis > automatic percutaneous lumbar discectomy.(5) There was no significant difference in reoperation rate, and the rank probability was total disc replacement > lumbar disc fusion > microdiscectomy > microendoscopic discectomy > standard open discectomy > percutaneous endoscopic lumbar discectomy > percutaneous laser disc decompression > chemonucleolysis > automatic percutaneous lumbar discectomy.(6) There were some statistical differences in incidence of complications, and the rank probability was percutaneous endoscopic lumbar discectomy > automatic percutaneous lumbar discectomy > standard open discectomy > microdiscectomy > percutaneous laser disc decompression > microendoscopic discectomy > total disc replacement > lumbar disc fusion > chemonucleolysis. Results suggested that microendoscopic discectomy and percutaneous endoscopic lumbar discectomy are effective in all aspects. Disc replacement and lumbar disc fusion are the best in success rate of operation. Chemonucleolysis is poor in success rate of operation, reoperation rate and complications rate. Percutaneous automatic discectomy is poor in success rate of operation and reoperation rate.

Long-term outcomes of cervical artificial disc replacement for patients with degenerative cervical canal stenosis / 中华骨科杂志

Objective To evaluate the long-term efficacy of cervical artificial disc replacement for patients with degenerative cervical canal stenosis.Methods All of 43 patienta underwent single level Bryan cervical artificial disc replacement for degenerative cervical canal stenosis were retrospectively analyzed with a minimum 10 years follow-up in our hospital between December 2003 and December 2007.There were 28 males and 15 females with an average age of 56.7 ± 8.0 years which ranged from 37 to 76 including 1 case of C3.4 level,11 xases of ~ level,26 cases of C~ level and 5 cases of C6,7 level.According to the symptoms and location of compression on radiograph,the patients were divided into 3 groups:15 patients in radiculopathy group,10 patients in myelopathy group and 18 patients in myeloradiculo p~hy group.Radidogical evaluation indexes include global range of motion (ROM),segmental ROM,segmental Cobb angle.Clinical evaluation indexes including Japanese Orthopaedic Association (JOA) score,neck disability index (NDI) and Odom's criteria.The variable data were analyzed by one-way ANOVA,the grading data were analyzed by Kruskal-Wallis H test.The preoperative and postoperative data were analyzed by paired t test.Results At the last follow-up,the Cobb angle of the operative segment was 1.29°±1.34°in myelopathy group(t=4.606,P=0.001),0.71°±2.20°in radiculopathy group (t=2.355,P=0.034),and 0.69°±2.12° in myeloradiculopathy group (t=3.312,P=0.004),which was significantly lower than that before operation.At the last follow-up,ROM of the operative segment in myelopathy group was 6.41 o ±4.87°,which was significantly lower than that before operation (11.46° ±5.19°,t=3.589,P＜ 0.05),and there was no significant difference in the other two groups.There was no significant difference in other imaging parameters among the three groups.JOA scores at the last follow-up were 16.33±0.75 in radiculopathy group (t=5.857,P＜ 0.001),16.00±1.05 in myelopathy group(t=8.337,P＜ 0.001) and 14.78±1.69 in radiculopathy group (t=4.045,P＜ 0.001);NDI were 13.07％±5.90％ in radiculopathy group (t=7.097,P＜ 0.001),12.60％±4.22％ in myelopathy group (t=7.319,P＜ 0.001) and 23.11％±14.18％ in radiculopathy group (t=4.229,P＜ 0.001),which were all significantly improved than those before operation.The excellent and good rate of Odom's criteria (H=2.719,2.411,P＜ 0.05),JOA (LAD-t=3.770,4.080,P＜0,05) and NDI(LAD-t=2.850,2.643,P＜ 0.05) at the last follow-up of the patients in radiculopathy group and myelopathy group were better than those of patients in myeloradiculopathy group (P＜ 0.05).Conclusion Cervical artificial disc replacement has a satisfied long-term clinical efficacy with degenerative cervical canal stenosis.The efficacy of myelopathy and radiculopathy were better than myeloradiculopathy.

Cost-Effectiveness Analysis of Cervical Anterior Fusion and Cervical Artificial Disc Replacement in the Korean Medical System

OBJECTIVE: This study is a retrospective cost-benefit analysis of cervical anterior interbody fusion and cervical artificial disc replacement, which are the main surgical methods to treat degenerative cervical disc disease. METHODS: We analyzed 156 patients who underwent anterior cervical disc fusion and cervical artificial disc replacement from January 1, 2008 to December 31, 2009, diagnosed with degenerative cervical disc disorder. In this study, the costs and benefits were analyzed by using quality adjusted life year (QALY) as the outcome index for patients undergoing surgery, and a Markov model was used for the analysis. Only direct medical costs were included in the analysis; indirect medical costs were excluded. Data were analyzed with TreeAge Pro 2015™ (TreeAge Software, Inc, Williamstown, MA, USA). RESULTS: Patients who underwent cervical anterior fusion had a total cost of KRW 2501807/USD 2357 over 5 years and obtained a utility of 3.72 QALY. Patients who underwent cervical artificial disc replacement received 4.18 QALY for a total of KRW 3685949/USD 3473 over 5 years. The cumulative cost-effectiveness ratio of cervical spine replacement surgery was KRW 2549511/QALY (USD 2402/QALY), which was lower than the general Korean payment standard. CONCLUSION: Both cervical anterior fusion and cervical artificial disc replacement are cost-effective treatments for patients with degenerative cervical disc disease. Cervical artificial disc replacement may be an effective alternative to obtain more benefits.

Progression of Ossification of the Posterior Longitudinal Ligament after Cervical Total Disc Replacement / 대한신경손상학회지

OBJECTIVE: Total disc replacement (TDR) is frequently performed anterior approaching method for the patients diagnosed with cervical disc herniation. This study aimed to assess the degree of ossification of the posterior longitudinal ligament (OPLL) progression after cervical TDR. METHODS: Twenty-two male soldiers who underwent cervical TDR surgery from 2009 to 2016 and were followed-up for more than 12 months were enrolled. The enrolled patients were classified as; 1) patients with pre-existing OPLL and without; and 2) patient showing progression of OPLL or not. RESULTS: Twenty-two men were included in the analysis. The mean follow-up period from the surgery was 41.4 months (range, 12–114 months). The mean age of all patients was 40.7 years (range, 31–52 years). TDR-only was used in 7 cases, and the hybrid surgery (TDR+ACDF) was used in 15 cases. The incidence of progression or newly development of OPLL was significantly higher in pre-existing OPLL group (p=0.01). In 11 cases showing the progression of the OPLL, the mean size of OPLL progression was 4.16 mm (range, 0.34–18.87 mm) in the longitudinal height and 1.57 mm (range, 0.54–3.91 mm) in thickness. CONCLUSION: The progression of OPLL after cervical TDR was more frequent in patients with pre-existing OPLL than in patients without OPLL. Even though TDR is a major alternative to the treatment of cervical lesions to preserve vertebral segmental motion, careful attention should be paid to whether TDR should be used in patients with OPLL and this should be fully explained to the patient.

Cost-Effectiveness Analysis of Cervical Anterior Fusion and Cervical Artificial Disc Replacement in the Korean Medical System

OBJECTIVE: This study is a retrospective cost-benefit analysis of cervical anterior interbody fusion and cervical artificial disc replacement, which are the main surgical methods to treat degenerative cervical disc disease.METHODS: We analyzed 156 patients who underwent anterior cervical disc fusion and cervical artificial disc replacement from January 1, 2008 to December 31, 2009, diagnosed with degenerative cervical disc disorder. In this study, the costs and benefits were analyzed by using quality adjusted life year (QALY) as the outcome index for patients undergoing surgery, and a Markov model was used for the analysis. Only direct medical costs were included in the analysis; indirect medical costs were excluded. Data were analyzed with TreeAge Pro 2015™ (TreeAge Software, Inc, Williamstown, MA, USA).RESULTS: Patients who underwent cervical anterior fusion had a total cost of KRW 2501807/USD 2357 over 5 years and obtained a utility of 3.72 QALY. Patients who underwent cervical artificial disc replacement received 4.18 QALY for a total of KRW 3685949/USD 3473 over 5 years. The cumulative cost-effectiveness ratio of cervical spine replacement surgery was KRW 2549511/QALY (USD 2402/QALY), which was lower than the general Korean payment standard.CONCLUSION: Both cervical anterior fusion and cervical artificial disc replacement are cost-effective treatments for patients with degenerative cervical disc disease. Cervical artificial disc replacement may be an effective alternative to obtain more benefits.

Disc replacement in lumbar spine / Artroplastia de disco na coluna lombar / Artroplastia de disco en la columna lumbar

ABSTRACT With the increase in the elderly population worldwide, the prevalence of degenerative diseases tends to grow, especially degenerative disc disease (DDD) in the lumbar spine. It is important to seek excellence treatments to ensure a better quality of life for patients. In this sense, the total disc replacement and the use of prostheses in the lumbar spine have been pointed out as alternative and promising treatments when compared to the standard treatment. The aim of this study is to show the results of total replacement of the intervertebral disc, through a review of the literature. The electronic search was performed in the PubMed databases, with the keywords "Total Disk Replacement", "Low Back Pain", and "Arthroplasty" in articles published as of 2012. We selected 16 articles. Level of Evidence: II. Type of study: Systematic reviewb of Level II studies or Level I studies with inconsistent results.

RESUMO Com o aumento da prevalência de idosos no mundo, a incidência de doenças degenerativas tende a crescer, especialmente a Doença degenerativa de disco (DDD) na coluna lombar. É importante buscar por tratamentos de excelência, para garantir melhor qualidade de vida aos pacientes. Nesse sentido, a substituição total do disco e o uso de próteses na coluna lombar tem sido apontados como tratamentos alternativos e promissores, quando comparado ao tratamento padrão. O objetivo deste artigo é mostrar os resultados da substituição total do disco intervertebral, por meio de uma revisão da literatura. Foi realizada a busca eletrônica nas bases de dados PubMed, a partir das palavras-chave: Substituição Total do Disco; Dor lombar; Artroplastia, publicados a partir de 2012. Foram selecionados um total de 16 artigos.Nível de Evidência: II. Tipo de estudo: Revisão sistemáticab de Estudos de nível II ou nível I com resultados discrepantes.

RESUMEN Con el aumento de la población de ancianos en todo el mundo, la prevalencia de enfermedades degenerativas tiende a crecer, especialmente la enfermedad degenerativa del disco (EDD) en la columna lumbar. Es importante buscar tratamientos de excelencia para garantizar una mejor calidad de vida a los pacientes. En este sentido, la sustitución del disco y el uso de prótesis en la columna lumbar han sido señalados como tratamientos alternativos y prometedores, en comparación con el tratamiento estándar. El objetivo de este estudio es mostrar los resultados de la sustitución total del disco intervertebral, por medio de una revisión de la literatura. Se realizó la búsqueda electrónica en las bases de datos PubMed, con los descriptores "Reemplazo total de disco", "Dolor lumbar", "Artroplastia", en artículos publicados a partir de 2012. Se seleccionaron 16 estudios. Nivel de Evidencia: II. Tipo de estudio: Revisión sistemáticab de Estudios de nivel II o nivel I con resultados discrepantes.

Are Controversial Issues in Cervical Total Disc Replacement Resolved or Unresolved?: A Review of Literature and Recent Updates

Since the launch of cervical total disc replacement (CTDR) in the early 2000s, many clinical studies have reported better outcomes of CTDR compared to those of anterior cervical discectomy and fusion. However, CTDR is still a new and innovative procedure with limited indications for clinical application in spinal surgery, particularly, for young patients presenting with soft disc herniation with radiculopathy and/or myelopathy. In addition, some controversial issues related to the assessment of clinical outcomes of CTDR remain unresolved. These issues, including surgical outcomes, adjacent segment degeneration (ASD), heterotopic ossification (HO), wear debris and tissue reaction, and multilevel total disc replacement (TDR) and hybrid surgeries are a common concern of spine surgeons and need to be resolved. Among them, the effect of CTDR on patient outcomes and ASD is theoretically and clinically important; however, this issue remains disputable. Additionally, HO, wear debris, multilevel TDR, and hybrid surgery tend to favor CTDR in terms of their effects on outcomes, but the potential of these factors for jeopardizing patients' safety postoperatively and/or to exert harmful effects on surgical outcomes in longer-term follow-up cannot be ignored. Consequently, it is too early to determine the therapeutic efficacy and cost-effectiveness of CTDR and will require considerable time and studies to provide appropriate answers regarding the same. For these reasons, CTDR requires longer-term follow-up data.

Rare Intractable Cervicalgia Related to Exaggerated Disc Height Distraction : Report of Two Cases and Literature Review

We present two cases of unexpected postoperative intractable cervicalgia due to over-sized implant insertion during simple anterior cervical decompression and fusion (ACDF) or artificial disc replacement (ADR). These patients experienced severe cervicalgia mostly related to their neck motion even after standard cervical operations. In both cases, the restored disc heights after the operations were prominently greater than the preoperative disc heights. The patients had not responded to any of the conservative treatments, and unloading of these excessively distracted segments through ultimate revision surgery led to dramatic pain relief. This report emphasizes the increase in distractional forces that takes place after a standard ACDF or ADR, as well as the importance of a proper sized implant. It also includes the reviews of other biomechanical or clinical reports dealing with this issue, thereby cautioning the surgeons not to disregard these factors, which might have an adverse effect in patients with cervicalgia even after radiographically successful cervical procedures.

Risk factors of dysphagia after single-level anterior cervical surgery / 中华骨科杂志

Objective To explore the incidence of dysphagia and its potential risk factors.Methods From January 2014 to December 2015,a total of 187 patients who underwent single-level anterior cervical spine surgery were recruited in this retrospective analysis study.Specific perioperative data including age,gender,smoking,alcohol use,BMI,estimated blood loss,surgical segment,length of incision,and length of hospital stay were recorded respectively.The Bazaz grading system and the swallowing quality of life (SWAL-QOL) score were used to assess the presence and severity of dysphagia.According to the Bazaz grading system,the patients were divided into dysphagia group and non-dysphagia group 1 week after operation.One-factor x2 test and one-sample t test were used to univariate analyze the two groups of related factors,and select the potential variables for multivariate logistic regression analysis to identify the risk factors leading to dysphagia.Results The number of dysphagia patient was 99 (52.94％) at 1 week after surgery,and 16 (8.56％) at 1 year.The preoperative mean SWAL-QOL score was 65.62±4.41 points,which decreased to 58.72±7.54 points after surgery and rose up to 64.66±5.26 points at the 12-month follow-up.The SWAL-QOL score at 1 week after surgery was correlated with the operative time (r=-0.474;P ＜ 0.001).Multivariate analysis indicated that preoperative tracheal exercise (OR=0.302,95％CI:0.131,0.748),operation time ＜ 60 min (OR=0.407,95％CI:0.190,0.878),and arthroplasty (OR=0.211,95％CI:0.102,0.425) were the independent factors to reduce the incidence of postoperative dysphagia.Conclusion The incidence and severity of dysphagia symptoms after single-level anterior cervical spine surgery gradually decreased with the extension of follow-up time.Preoperative tracheal exercise,shortened operative time and manual artificial disc replacement may be helpful to reduce the postoperative occurrence of dysphagia.

Rare Intractable Cervicalgia Related to Exaggerated Disc Height Distraction : Report of Two Cases and Literature Review

We present two cases of unexpected postoperative intractable cervicalgia due to over-sized implant insertion during simple anterior cervical decompression and fusion (ACDF) or artificial disc replacement (ADR). These patients experienced severe cervicalgia mostly related to their neck motion even after standard cervical operations. In both cases, the restored disc heights after the operations were prominently greater than the preoperative disc heights. The patients had not responded to any of the conservative treatments, and unloading of these excessively distracted segments through ultimate revision surgery led to dramatic pain relief. This report emphasizes the increase in distractional forces that takes place after a standard ACDF or ADR, as well as the importance of a proper sized implant. It also includes the reviews of other biomechanical or clinical reports dealing with this issue, thereby cautioning the surgeons not to disregard these factors, which might have an adverse effect in patients with cervicalgia even after radiographically successful cervical procedures.

Clinical and Radiographic Results of Artificial Disc Replacement Combined with Anterior Cervical Discectomy and Fusion Versus Two-Level Anterior Cervical Discectomy and Fusion in Two-Level Cervical Disc Disease

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: To compare the clinical and radiographic outcomes of a hybrid construct (HC) of cervical artificial disc replacement (CADR) combined with anterior cervical discectomy and fusion (ACDF) (group I) with 2-level ACDF (group II) in patients with 2-level cervical disc disease. SUMMARY OF LITERATURE REVIEW: ACDF is reported to potentially promote degenerative changes in the adjacent segment. CADR has been expected to reduce the risk of adjacent segment degeneration. However, its clinical course has yet to be sufficiently clarified. MATERIALS AND METHODS: Twenty-six patients underwent 2-level cervical disc surgery. Single-level CADR combined with ACDF was performed in 14 patients. Twelve patients underwent 2-level ACDF. Clinical profiles were assessed using the neck disability index (NDI) and visual analogue scale scores of arm and neck pain. Dynamic lateral cervical radiographs were obtained preoperatively and at 1, 6, 12, and 18 months postoperatively. The range of motion (ROM) of the overall cervical spine (C2-7) and the adjacent segments was measured. RESULTS: Group I showed superior NDI 18 months postoperatively (p 0.05). CONCLUSIONS: The HC group showed comparable clinical and radiographic outcomes to those of the 2-level ACDF group. HC can be used selectively in the treatment of patients with 2-level cervical disc disease.

Radiographic Analysis of the Lumbosacral Juncture: Is There a Critical Sacral Angle for Total Disc Replacement?

STUDY DESIGN: Retrospective review of a patient cohort through a prospective study. PURPOSE: To determine whether there are correlations between radiographic measurements, including sacral slope (SS) and pelvic incidence (PI), and self-reported clinical outcomes among single-level L5/S1 ProDisc-L patients. OVERVIEW OF LITERATURE: The lumbosacral juncture presents unique biomechanical challenges with respect to artificial disc replacement (ADR) because of its orientation and consequential shear loading. Reports of inferior outcomes at L5/S1 compared to those of the outcomes at the levels above, including increased facet joint pain, suggest a relationship with the sacral inclination at L5/S1. METHODS: Plain standing lateral radiographs of 71 patients (age, 26–65 years) who underwent ADR at L5/S1 for degenerative disc disease were reviewed. SS and PI were measured based on pretreatment and initial follow-up standing films. Patient's average adjusted self assessments included the Oswestry disability index and visual analog scale for pain 2 years after ADR. Correlation coefficients were computed to evaluate relationships between radiographic parameters and clinical outcomes. Analysis of covariance was used to evaluate multivariate relationships among factors, including radiographic parameters, body mass index (BMI), and clinical outcomes. RESULTS: SS and PI values were obtained from 71 patients. The average SS was 33.3° and average PI was 39.9°. At the 24-month follow-up, no significant correlations (p≥0.05) were observed between radiographic parameters and clinical outcomes. BMI, age, and sex did not explain any variability in the relationships between clinical outcomes and SS and PI. CONCLUSIONS: We reviewed a large range of SS angles and found no associations between SS, PI, or BMI and clinical outcomes after ADR at L5/S1. These preliminary results demonstrate that ADR provided maintainence of pain relief and functional improvement for a wide range of SS angles, suggesting that steeper angles are not a contraindication for ADR.

A Comparison of Anterior Cervical Discectomy and Fusion versus Fusion Combined with Artificial Disc Replacement for Treating 3-Level Cervical Spondylotic Disease

OBJECTIVE: The purpose of this study is to evaluate the efficacy and safety of 3-level hybrid surgery (HS), which combines fusion and cervical disc replacement (CDR), compared to 3-level fusionin patient with cervical spondylosis involving 3 levels. METHODS: Patients in the anterior cervical discectomy and fusion (ACDF) group (n=30) underwent 3-level fusion and the HS group (n=19) underwent combined surgery with fusion and CDR. Clinical outcomes were evaluated using the visual analogue scale for the arm, the neck disability index (NDI), Odom criteria and postoperative complications. The cervical range of motion (ROM), fusion rate and adjacent segments degeneration were assessed with radiographs. RESULTS: Significant improvements in arm pain relief and functional outcome were observed in ACDF and HS group. The NDI in the HS group showed better improvement 6 months after surgery than that of the ACDF group. The ACDF group had a lower fusion rate, higher incidence of device related complications and radiological changes in adjacent segments compared with the HS group. The better recovery of cervical ROM was observed in HS group. However, that of the ACDF group was significantly decreased and did not recover. CONCLUSION: The HS group was better than the ACDF group in terms of NDI, cervical ROM, fusion rate, incidence of postoperative complications and adjacent segment degeneration.

Comparative Analysis between Total Disc Replacement and Posterior Foraminotomy for Posterolateral Soft Disc Herniation with Unilateral Radiculopathy : Clinical and Biomechanical Results of a Minimum 5 Years Follow-up

OBJECTIVE: To compare the clinical outcomes and biomechanical effects of total disc replacement (TDR) and posterior cervical foraminotomy (PCF) and to propose relative inclusion criteria. METHODS: Thirty-five patients who underwent surgery between 2006 and 2008 were included. All patients had single-level disease and only radiculopathy. The overall sagittal balance and angle and height of a functional segmental unit (FSU; upper and lower vertebral body of the operative lesion) were assessed by preoperative and follow-up radiographs. C2–7 range of motion (ROM), FSU, and the adjacent segment were also checked. RESULTS: The clinical outcome of TDR (group A) was tended to be superior to that of PCF (group B) without statistical significance. In the group A, preoperative and postoperative upper adjacent segment level motion values were 8.6±2.3 and 8.4±2.0, and lower level motion values were 8.4±2.2 and 8.3±1.9. Preoperative and postoperative FSU heights were 37.0±2.1 and 37.1±1.8. In the group B, upper level adjacent segment motion values were 8.1±2.6 and 8.2±2.8, and lower level motion values were 6.5±3.3 and 6.3±3.1. FSU heights were 37.1±2.0 and 36.2±1.8. The postoperative FSU motion and height changes were significant (p<0.05). The patient’s satisfaction rates for surgery were 88.2% in group A and 88.8% in group B. CONCLUSION: TDR and PCF have favorable outcomes in patients with unilateral soft disc herniation. However, patients have different biomechanical backgrounds, so the patient’s biomechanical characteristics and economic status should be understood and treated using the optimal procedure.

Effect of different heights of artificial cervical disc replacement on the range of motion of the treated segment / 中华骨科杂志

Objective To cxplore the variation of the range of motion (ROM) of operative level after different heights of artificial cervical disc replacement,and to provide guidance for clinical work in selecting appropriate height of artificial cervical disc prosthesis.Methods The preoperative cervical anteroposterior and lateral Ⅹ-rays of 9 fresh male cadaveric cervical spine specimens were obtained to measure the intervertebral height of C5-6,and 3 screened specimens with the height of about 5 mm were included in the experiment.The experiment was designed to test self-control,and other four groups of cervical specimens including intact group,appropriate height (5 mm) of C5.6 artificial cervical disc replacement group,1mm increased (6 mm) group and 2 mm increased (7 mm) group were made biomechanical test sequentially.The specimens were fixed to the cervical three-dimensional movement machine,with a 75 N follower load and pure moments of 2 Nm for flexion/extension 、left/right bending and left/right axial rotation,to measure the ROM of operative level under the condition of changes in 0.2 Nm/s.Results There were no significant differences in the ROM of flexion/extension,lateral bending and axial rotation between 5 mm group and intact group;the ROM of flexion/extension、lateral bending and axial rotation in 6 mm group increased compared with 5 mm group,but the difference was not statistically significant;the ROM of flexion/extension in 7 mm group was significantly less than that of intact,5mm and 6 mm group (9.5°± 1.0° vs 12.5°±0.9°、11.3°±0.8°、11.6°±0.9°),but significantly greater in axial rotation than 6 mm group (10.4°±1.4°vs 8.6°±0.3°),and there was no significant difference in lateral bending compared with other 3 groups.Conclusion 2 adjacent heights of cervical disc prostheses are implantedsuitably when testing the mold of disc prosthesis,the choice of cervical disc prosthesis with 1 mm increased can improve the ROM of operative level to some extent;while the height with 2 mm increased can lead to the ROM of flexion/extension at the operative level reduced,but the ROM of rotation shows an increasing trend.

The influence of intramedullary hyperintensity on T2-weighted MRI on the outcome of cervical arthroplasty for cervical spondylotic myelopathy / 中华骨科杂志

Objective To investigate whether the hyperintensity on T2?weighted MRI affects the outcome of cervical ar?throplasty (CA) for cervical spondylotic myelopathy (CSM). Methods 69 patients with CSM who had undergone CA between June 2005 and December 2007 were retrospectively reviewed. They were divided into three groups according to the intensity of T2?weighted images:Group A, whose intensity of T2?weighted images in spinal cord compression spot was equisignal;Group B, hyper?intensity with obscure border; Group C, hyperintensity with clear border. There were 22 males and 19 females in group A aged from 27 to 63 years old, whose duration of disease was between 3 to 72 months, and there were 34 single?segment cases, 5 double?segment and 2 triple?segment cases. There were 9 males and 9 females in group B aged from 30 to 61 years old whose duration of disease was between 3 to 24 months, and there were 12 single?segment and 6 double?segment cases. There were 4 males and 6 fe?males in group C aged from 28 to 56 years old whose duration of disease was between 1 to 24 months, and there were 8 single?seg?ment and 2 double?segment cases. Two types of artificial cervical disc were used:Bryan Disc in 42 cases and Prodisc?C in 44 cas?es. The duration of Group A (24.7 ± 27.9 months) was significantly longer than that in Group B (6.6 ± 7.4 months) and Group C (11.1±9.5 months). The follow?up period was from 48 to 86 months with an average time of 61 months. The preoperative X?ray and MR as well as postoperative X?ray were collected. The history, compress ratio of MRI, the ROM of cervical segments pre and post?operatively were recorded and Japanese Orthopaedic Association (JOA) was used to evaluate the neurological function. Results Preoperative compress ratio of MRI were 43.3%± 15.2%, 42.4%± 10.7%and 41.9%± 14.8%respectively;preoperative segmental ROM were 9.6°±2.5°, 9.0°±1.7° and 9.1°±1.9° respectively. Preoperative JOA score were 13.6±1.2, 13.1±1.3 and 12.9±1.8, re?spectively. Postoperative JOA score at the latest follow?up were 16.2±1.0, 15.8±1.2 and 15.7±1.6 respectively. There was no statis?tic difference among these groups. Preoperative increased signal intensify on T2?weighted MRI in patients with cervical spondylot?ic myelopathy may not affect the outcome of cervical arthroplasty.

Cervical Footprint Anthropometry in Indian Population: Implications on Design of Artificial Disc Replacement Devices

STUDY DESIGN: Cross-sectional study. PURPOSE: To accurately measure the dimensions of cervical endplates based on computed tomography (CT) scans in Indian population and assess accuracy of match with currently available cervical disc prostheses. OVERVIEW OF LITERATURE: The dimensions of currently available cervical disc replacement implants are based on early published geometrical measurements of vertebrae endplates for Caucasian population. To author's knowledge, similar study has not been published for patients from Indian subcontinent. METHODS: CT scans of cervical spine of patients from Indian subcontinent were collected and reviewed. Seventy patients (54 men and 16 women; aged 18-56 years with average of 37 years) who underwent CT scans of cervical spine were included in study. 3D CT scans of sub axial cervical spine (C3 to C7) were analyzed. The anterior-posterior (AP) and central mediolateral (CML) dimensions of superior and inferior endplates from C3 to C7 were measured using digital measuring system. RESULTS: A total of 560 endplates of 70 patients were included in the study. The AP diameter of cervical endplates ranged from 0.87 to 2.47 cm. The CML diameters ranged from 0.84 to 2.98 cm. For levels C3/C4 and C4/C5 for AP dimension Prestige-LP (90.5%) and Prodisc-C (89%) discs showed higher percentage of matching than Discover discs (58.5%). For CML diameter, Prestige-LP (69.5%), Prodisc-C (70%) and Discover (39.5%) discs showed almost similar matching with measured endplates. For levels C5/C6 and C6/C7 for AP dimension, Prestige-LP (67.25%), Prodisc-C (49.35%) and Discover (51.5%) discs showed similar matching. For CML diameter Prestige-LP (32%), Prodisc-C (27.5%) and Discover (42.2%) discs showed poor matching with measured endplates. CONCLUSIONS: This study indicates need for redesign of cervical disc prostheses to match Indian patients. The collected anthropometric dimensions from this study may be used to design and develop indigenous artificial total disc replacement prosthesis and even cervical cages in India. With the present study being a small pilot study, the authors recommend anthropometric CT measurements in larger number of Indian patients in order to validate footprint dimensions for designing better-matched prosthesis.

The correlation between patient selection and heterotopic ossification after cervical artificial disc replacement / 中华骨科杂志

Objective To analysis the correlation between patient selection and heterotopic ossification (HO) after cervical artificial disc replacement.Methods Data of 48 patients with cervical spondylosis (34 cervical spondylotic myelopathy and 14 nerve-root type) who had undergone Bryan cervicadisc replacement from December 2003 to December 2008 were reviewed retrospectively,and all the patients had been followed up for more than 5 years.There were 21 males and 27 females with an average age of 42 years old (range,20-53 years).There were 38 single level replacement (C3-4 3 cases,C4-5 5 cases,C5-6 28 cases,C6-7 2 cases),9 double level replacement (C4-5,C5 6 4 cases;C5-6,C6-7 5 cases) and 1 three level replacement (C3-4,C4 5,C5-6) as a total of 59 surgical segments.The occurrence of HO was defined by McAfee classification on cervical lateral X-ray.Four factors were used in patient selection including gender,range of motion (ROM) of the target level,alignment of the functional spine unit (FSU) of the index level,and the disc height ratio between surgical level and the adjacent levels.The correlation between these four factors and HO was evaluated by logistic regression.The receiver operating characteristic (ROC) curve and area under the ROC curve were used to evaluate the significant result of logistic regression and the optimal diagnostic value.Results 48 patients were all followed up for an average period of 70.3 months (range,60-120 months).The occurrence rate in this study was 33.9％ (20/59 segments).Only one factor,the disc height ratio of the target level and its adjacent levels,presented statistical correlation with HO.ROC analysis showed that the area under the ROC curve of disc height ratio was 0.813 and the optimal diagnostic threshold was 0.9.Conclusion The disc height ratio of the target level and adjacent levels was the only patient selective factor correlated with the occurrence of HO.For those with disc height loss exceeding 10％ comparing to adjacent levels,it is not indicated for cervical artificial disc replacement with Bryan prosthesis.