Long-term clinical efficacy of cervical artificial disc replacement for cervical spondylotic radiculopathy / 中国修复重建外科杂志

Objective: To evaluate the long-term efficacy and influencing factors of cervical artificial disc replacement (CADR) for patients with cervical spondylotic radiculopathy (CSR). Methods: The data of 29 CSR patients who underwent Bryan artificial disc replacement between December 2003 and December 2007 and followed up more than 10 years were retrospectively analysed. There were 16 males and 13 females with an average age of 54.1 years (range, 40-70 years). The disease duration was 2-144 months (mean, 19.2 months). CT and MRI were performed before operation to identify the compression segments (C 3, 4 in 2 cases, C 4, 5 in 6 cases, C 5, 6 in 18 cases, C 6, 7 in 3 cases) and the compression factors. According to the compression factor, the patients were divided into 2 groups: 14 patients with cervical disc herniation were in the group A and 15 patients combined with osteophyte were in the group B. There was no significant difference in gender, age, disease duration, and compressed level between 2 groups ( P>0.05). The radiographic and clinical evaluation indexes were recorded before operation and at last follow-up. The radiographic evaluation indexes included the global cervical and segmental range of motion (ROM), loss of ROM (ROM0.05). Except that the loss of ROM (ROM0.05). The results of clinical evaluation indexes showed that the NDI was significantly improved in both groups ( P0.05). The excellent and good rate of overall efficacy reached 100% in both groups. Conclusion: CADR has satisfied long-term efficacy in treating CSR. The maintenance of segmental mobility was better in patients with disc herniation than in patients with disc herniation and osteophyte.

Analysis of influence of shell angle of cervical artificial disc on long-term effectiveness of cervical artificial disc replacement / 中国修复重建外科杂志

Objective: To evaluate the influence of the shell angle of cervical artificial disc on long-term effectiveness of cervical artificial disc replacement (CADR). Methods: The clinical data of 71 patients who were treated with single-level CADR with Bryan prosthesis between December 2003 and December 2007 and followed up more than 10 years, were retrospectively analyzed. There were 44 males and 27 females with an age of 26-69 years (mean, 45.9 years). According to the shell angle of the cervical artificial disc which was measured on the postoperative lateral X-ray film, the patients were divided into kyphotic group (shell angle was negative) and non-kyphotic group. The following evaluation indexes before operation and at last follow-up were compared between 2 groups. Radiographic indexes included the range of motion (ROM) of cervical spine, the ROM of operated level, Cobb angle of operated level (the negative value indicated that the segmental kyphosis occurred at operated level), paravertebral ossification (PO) grades (grades 3 and 4 were high grade PO). Clinical indexes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and overall effectiveness evaluation (Odom criteria). Results: There were 24 patients in kyphotic group and 47 patients in non-kyphotic group. There was no significant difference in baseline data including gender, age, and operated level between 2 groups ( P>0.05). All the patients in 2 groups were followed up 121-165 months (mean, 128 months). There was no significant difference in preoperative ROM of cervical spine and ROM of operated level between 2 groups ( P>0.05); but the preoperative Cobb angle of operated level in kyphosis group was significantly lower than that in non-kyphotic group ( t=2.636, P=0.013). There was no significant difference in ROM of cervical spine at last follow-up between 2 groups ( t=1.393, P=0.168), however, the ROM and the Cobb angle of operated level in kyphotic group were significantly lower than those in non-kyphotic group ( P0.05). Conclusion: The shell angle of cervical artificial disc may lead to a decrease in the postoperative segmental ROM, and an increased occurrence of segmental kyphosis and high incidence of PO.

Effect of Bryan cervical disc replacement on cervical curvature and replacement segment in treating cervical spondylosis / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the effect of Bryan cervical disc replacement on cervical curvature and replacement segment in the treatment of cervical spondylosis, and analyze its clinical efficacy.</p><p><b>METHODS</b>Forty-nine patients underwent Bryan artificial cervical disc replacement from August 2010 to August 2013 were retrospectively analyzed. There were 26 males and 23 females, aged from 27 to 66 years old with an average of 48.5 years. Including 21 cases of nerve root type, 16 cases of spinal cord type, 12 cases of mixed type. And 21 cases were single segment replacement, 28 cases were double segments replacement. Preoperative and postoperative pain was compared using visual analogue scale(VAS);cervical function was observed by Japanese Orthopedic Association Scores (JOA) and Neck Disability Index (NDI);cervical lordosis curvature, function spinal unit(FSU) curvature, activities of replacement and adjacent segment, FSU activity were measured by cervical X-rays. Clinical effects were evaluated by the Odom method.</p><p><b>RESULTS</b>All the patients were followed up for 18.5 to 37.3 months with an average of 33.1 months. Pvoperative VAS, JOA, NDI scores were 7.08±1.55, 5.2±1.9, 39.96±7.06 before operation, 3.76±2.33, 13.20±1.20, 25.20±6.64 at 3 months after operation, and 2.80±1.50, 14.3±1.6, 24.24±7.89 at the last follow-up. Patients at three months and the last follow-up after operation were obviously improved in their VAS, JOA, and NDI scores (<0.05). There was no significant difference between the scores at last follow-up and 3 months after operation. Cervical lordosis changed from (10.64±4.26)° preoperatively to (13.68±4.56) ° at the last follow-up;the FSU curvature from (5.40±0.41) °to (9.92±2.00) °at the last follow-up (<0.05). The range of motion of the cervical spine preoperatively, 3 month postoperatively, and at the last follow-up were(70.84±6.17)°, (60.00±6.58)°, (71.48±4.61)°; FSU activities were(12.00±0.49)°, (9.36±0.26)°, (12.52±0.33)°;the activities of replacement segment were (10.48±0.67)°, (7.24±0.34)°, (9.28±0.36)°;the activities of upper segment of replacement were (10.52±0.60)°, (8.60±0.30)°, (10.44±0.43)°;the activities of lower segment of replacement were (8.48±0.40)°, (6.56±0.36)°, (9.60±0.39)°;there were significant differences in above items preoperatively and 3 months postoperatively(<0.05); and there were no significant difference preoperatively and at the last follow-up(>0.05). Pharyngeal discomfort and hoarseness occurred in 5 cases, and were recovered within 2 weeks after operation;heterotopic ossification occurred in 1 case at 6 months after operation;displacement of prosthesis occurred in 1 case at 12 months after operation. Based on Odom standard to evaluate the clinical outcome, 20 cases obtained excellent results, with 27 good, 2 general.</p><p><b>CONCLUSIONS</b>Bryan artificial cervical disc replacement not only generate good clinical effects, but may also restore the cervical lordosis and FSU curvature, while retaining the activities of replacement segment, and restoring overall cervical biomechanical functions.</p>

Case control study on Mobi-C cervical artificial disc replacement and anterior cervical decompression MC+fusion for the treatment of cervical spondylosis / 中国骨伤

<p><b>OBJECTIVE</b>To compare the clinical effects and clinical indications between Mobi-C cervical artificial disc replacement (CADR) and MC+ anterior cervical decompression and fusion(ACDF) in treating cervical spondylosis.</p><p><b>METHODS</b>The clinical data of 100 patients with cervical spondylosis treated ACDF or CADR from June 2009 to June 2015 were retrospectively analyzed. There were 53 males and 47 females, aged from 38 to 70 years old. Among them, 50 cases were treated by ACDF (ACDF group), follow-up time was for 22 to 42 months with an average of (32.24±5.20) months;other 50 cases were treated by CADR (CADR group), follow-up time was for 23 to 48 months with an average of (30.40±5.66) months. Odom criterion was used to evaluate the clinical effects in two groups. JOA score, including sensory function, motor function and bladder function was used to assess the spinal cord function. Preoperative and postoperative responsible intervertebral space heights, cervical curvatures were compared by image data between two groups.</p><p><b>RESULTS</b>All incisions obtained good healing and no serious complications were found. At final follow-up, 30 cases got excellent results, 12 good, 8 fair in ACDF group;and 34 cases got excellent results, 10 good, 6 fair in CADR group;there was no significant difference between two groups(u=4.000, =0.827). At final follow-up, the scores of sensory function and motor function were obviously improved(<0.05), and bladder function had not obviously recovered (>0.05) in two groups;and CADR group in the scores of sensory function and motor function were obviously better than of ACDF group(<0.05). There was no significant difference in preoperative intervertebral space height, cervical curvature between two groups, and at final follow-up both had different recovered. The recovery of CADR group was obviously better than of ACDF group.</p><p><b>CONCLUSIONS</b>CADR can quickly recover normal action for patients and retains the movement. CADR has certain advantages in recovering cervical curvature, improveing sensory function and motor function, but it is not able to completely replace ACDF.</p>

Finite element analysis on inferior cervical spine biomechanics after semi-constrained cervical intervertebral disc arthroplasty and anterior cervical discectomy and fusion / 医用生物力学

Objective To study biomechanical properties such as range of motion (ROM), intervertebral disc stress, ligament tension of inferior cervical spinal segment after the treatment of Discover, Prodisc-C artificial intervertebral disc replacement, and anterior cervical discectomy and fusion (ACDF), as well as mechanical property changes of the prosthesis after implantation. Methods Three kinds of operation plan on C5-6 cervical disc degeneration were established: Discover model, Prodisc-C model and ACDF model, as well as C4-7 segment original model of cervical vertebra. Biomechanical property changes after operation in cervical spine C4-7 segment in sagittal, coronal and transverse section were analyzed. Results ROM changes of cervical segment C5-C6 were as following: in Discover model it increased by 12.7%-73.1%, Prodisc-C model increased by 74%-98%, ACDF decreased by 55.8%-71.8%. The stress of C4-5 intervertebral disc after Discover artificial disc replacement showed no obvious increase, while the stress of C6-7 intervertebral disc decreased by 33.2%-54.2% under flexion, extension and axial rotation conditions. The amplification of ligament tension in Discover model decreased by 30%-40% as compared to that in Prodisc-C model. The maximum stress of Discover model (36.72 MPa) appeared under flexion condition, which was smaller than that in Prodisc-C model. Conclusions Artificial disc replacement can help to keep movement performance for segment after surgery. As a newly developed artificial intervertebral disc prosthesis, Discover makes some progress in the aspect of decreasing ligament stress and maintaining spinal stability. The research findings will provide theoretical basis for the clinical study on ACDF and artificial cervical intervertebral disc replacement surgeries.

Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

OBJECTIVE: To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group. METHODS: Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group. RESULTS: In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM) of C3-7 in all directions in the non-fusion group compared with the intact group (p>0.05), but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (p<0.05). The ROM of adjacent segments (C3-4, C6-7) of the non-fusion group decreased significantly in some directions compared with the fusion group (p<0.05). Significant differences in the C4-6 ROM in some directions were detected between the non-fusion group and the intact group. In the fusion group, the C4-6 ROM in all directions decreased significantly compared with the intact and non-fusion groups (p<0.01). The stability index ROM (SI-ROM) of some directions was negative in the non-fusion group, and a significant difference in SI-ROM was only found in the C4-6 segment of the non-fusion group compared with the fusion group. CONCLUSION: An artificial disc and vertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger ...

Clinical application of artificial lumbar disc replacement:Present and future / 中国组织工程研究

BACKGROUND:The basic idea of artificial disc replacement is the intension to minimize the impact on adjacent segments based on the premise of stabilizing index segment, then prevent and reduce the incidence of adjacent segment degeneration. OBJECTIVE:To explore the indications and contraindications of artificial disc replacement, peri-operative economics considerations, long-term complications, as wel as the effect of artificial lumbar disc replacement combined with fusion surgery. METHODS:The PubMed database, CNKI database and SinoMed database over the past decade were searched for the related articles. The retrospective and prospective clinical trials of artificial lumbar disc replacement were included. Repetitive studies and stale perspectives were excluded. A total of 34 articles were summarized and analyzed in the end. RESULTS AND CONCLUSION:Since the first artificial lumbar disc prosthesis designed to be commercial y distributed in 1982, there have been a plenty of clinical trials on lumbar disc replacement. However, there is no answer to many problems that encountered in clinical trials. The effect of the number of replaced segment on the clinical outcomes, the effect of facet joint degeneration on the clinical outcomes, selection of the patients with the history of lumbar disc surgery, age of the patients and the rest time before disc replacement should be taken into consideration in the researches on indications and contraindications of artificial disc replacement. The intraoperative blood loss, operation time and hospital stay after replacement can be used to evaluate whether lumbar disc replacement is better than the traditional lumbar fusion surgery or not. The complications after lumbar disc replacement include heterotopic ossification, implants mechanical failure, and facet joint and adjacent segment degeneration. The combination of lumbar disc replacement and fusion surgery for the treatment of multi-segmental lumbar disc diseases can achieve complement and thus obtaining the efficacy that better than the application of one surgery alone.

Unusual Fatal Infections after Anterior Cervical Spine Surgeries

We report two cases of cervical spinal epidural abscess (SEA), which are related to anterior cervical surgeries. The first case reveals a late postoperative infection without any predisposing factor. The second case reveals combined complication of infection and instrument failure (artificial disc). Both two cases manifested ascending infections that are unusual courses of anterior cervical infections. The abscess extended upwards and, finally, caused life threatening bacterial meningitis. We suggest aggressive surgical interventions with anti-bacterial therapies in such cases.

The Correlation between Insertion Depth of Prodisc-C Artificial Disc and Postoperative Kyphotic Deformity: Clinical Importance of Insertion Depth of Artificial Disc

OBJECTIVE: This study was designed to investigate the correlation between insertion depth of artificial disc and postoperative kyphotic deformity after Prodisc-C total disc replacement surgery, and the range of artificial disc insertion depth which is effective in preventing postoperative whole cervical or segmental kyphotic deformity. METHODS: A retrospective radiological analysis was performed in 50 patients who had undergone single level total disc replacement surgery. Records were reviewed to obtain demographic data. Preoperative and postoperative radiographs were assessed to determine C2-7 Cobb's angle and segmental angle and to investigate postoperative kyphotic deformity. A formula was introduced to calculate insertion depth of Prodisc-C artificial disc. Statistical analysis was performed to search the correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity, and to estimate insertion depth of Prodisc-C artificial disc to prevent postoperative kyphotic deformity. RESULTS: In this study no significant statistical correlation was observed between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity regarding C2-7 Cobb's angle. Statistical correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity was observed regarding segmental angle (p<0.05). It failed to estimate proper insertion depth of Prodisc-C artificial disc effective in preventing postoperative kyphotic deformity. CONCLUSION: Postoperative segmental kyphotic deformity is associated with insertion depth of Prodisc-C artificial disc. Anterior located artificial disc leads to lordotic segmental angle and posterior located artificial disc leads to kyphotic segmental angle postoperatively. But C2-7 Cobb's angle is not affected by artificial disc location after the surgery.

Current concept on the operative treatment for degenerative cervical disc disease

Degenerative changes in the cervical spinal column are common in the adult population. Although most patients respond well to initial nonsurgical management, those who continue to have symptoms or patients with clinically evident myelopathy are candidates for surgical intervention. The objective of this article is to review and discuss the surgical treatment for degenerative cervical spine disease. Anterior cervical spine surgery is commonly used to treat numerous pathologic entities and is expected to increase with the development of surgical techniques and instruments. Autogenous tricortical iliac crest struts are the best option for anterior fusion, but they are associated with donor site morbidity. Equivalent fusion rates have been reported after allografting and autografting, combined with the use of anterior plates. Artificial disc replacement, one of the emerging motion-sparing technologies, is currently used and has shown excellent results. However, longer follow-up is needed to determine whether these devices can function well over time. Surgical treatments in degenerative cervical disease have shown excellent results. Appropriate methods that take into account the pathologic status of the patient and the surgeon's surgical experience can prevent complications and lead to excellent surgical outcomes.

Comparative Analysis of Cervical Disc Arthroplasty Using Two Types of Artificial Cervical Discs: Bryan(R) versus Mobi-C(R)

OBJECTIVE: Since the 1990s, due to postoperative loss of mobility and adjacent segmental disease after anterior cervical fusion, many different types of cervical artificial discs have been developed as alternative implants. The purposes of this study are investigation and comparison of radiographic and clinical outcomes between two different types of prostheses, Bryan(R) and Mobi-C(R). METHODS: We retrospectively evaluated 33 patients who were treated for cervical degenerative disc disease that resulted in radiculopathy and/or myelopathy between May 2004 and April 2009. Seventeen patients underwent Bryan(R) cervical disc arthroplasty and sixteen patients underwent Mobi-C(R) arthroplasty. The radiographic outcomes were assessed by measuring the cervical lordosis, segmental lordosis, range-of-motion (ROM) of the cervical spine (C2-7), functional segmental unit (FSU), prosthesis' shell and the upper adjacent segment. The clinical results were evaluated according to the Visual Analogue Scale (VAS) for axial pain and radiculopathy, Odom's criteria, and the modified Prolo's economic and functional outcome rating scale. RESULTS: The age of the study population ranged from 24 to 69 years with a mean age of 48 years vs. 46 years in the Bryan(R) and Mobi-C(R) groups, respectively. The mean duration of follow-up was 23.7 months in the Bryan(R) group and 11.3 months in the Mobi-C(R) group. The changes of overall cervical sagittal angle were not significantly different between two groups, but the increase of segmental sagittal angle (0.85degrees in Bryan(R), 8.04degrees in Mobi-C(R)), ROM of the FSU(-0.51degrees in Bryan(R), 2.47degrees in Mobi-C(R)) and ROM of the shell (1.77degrees in Bryan(R), 5.28degrees in Mobi-C(R)) were significantly higher in Mobi-C(R) group than in Bryan(R) group (p<0.05). The clinical results were not significantly different between two groups. CONCLUSION: The Mobi-C(R) prosthesis showed more favorable radiographic results than that of the Bryan(R) prosthesis, however, the clinical outcomes were similar in both groups. Large-scale and long-term follow-up studies are needed to confirm our results.

Biomechanical Changes of the Lumbar Segment after Total Disc Replacement : Charite(R), Prodisc(R) and Maverick(R) Using Finite Element Model Study

OBJECTIVE: The purpose of this study was to analyze the biomechanical effects of three different constrained types of an artificial disc on the implanted and adjacent segments in the lumbar spine using a finite element model (FEM). METHODS: The created intact model was validated by comparing the flexion-extension response without pre-load with the corresponding results obtained from the published experimental studies. The validated intact lumbar model was tested after implantation of three artificial discs at L4-5. Each implanted model was subjected to a combination of 400 N follower load and 5 Nm of flexion/extension moments. ABAQUStrade mark version 6.5 (ABAQUS Inc., Providence, RI, USA) and FEMAP version 8.20 (Electronic Data Systems Corp., Plano, TX, USA) were used for meshing and analysis of geometry of the intact and implanted models. RESULTS: Under the flexion load, the intersegmental rotation angles of all the implanted models were similar to that of the intact model, but under the extension load, the values were greater than that of the intact model. The facet contact loads of three implanted models were greater than the loads observed with the intact model. CONCLUSION: Under the flexion load, three types of the implanted model at the L4-5 level showed the intersegmental rotation angle similar to the one measured with the intact model. Under the extension load, all of the artificial disc implanted models demonstrated an increased extension rotational angle at the operated level (L4-5), resulting in an increase under the facet contact load when compared with the adjacent segments. The increased facet load may lead to facet degeneration.

Load Distribution in Functional Spinal Unit with SB Charite III(R) Artificial Disc; Finite Element Analysis

OBJECTIVE: To evaluate the effects of SB Charite III(R) artificial disc implantation on the biomechanics of functional spinal units. METHODS: A nonlinear intact osteoligamentous three-dimensional finite element model of L4-L5 was developed using 1-mm CT scan data from a human volunteer, and the material properties of each element were determined. The model was validated using biomechanical data. A model that was implanted with SB Charite III(R) artificial discs via an anterior approach was also developed. The stresses and strains of the vertebral bodies and surrounding spinal ligaments were investigated. The implanted model was compared to the intact model in terms of range of motion, force on facet joints with flexion-extension, lateral bending, and axial rotation under 400 N preloading. RESULTS: There were no significant differences between the findings of this finite element study and other reports in the literature. Our analytical method proved useful method for the biomechanical evaluation of the effects of artificial disc implantation. The implanted model revealed an increased range of motion in flexion-extension, lateral bending, and axial rotation compared to the intact model. The stresses on facets were greater in the implanted model than in the intact model. CONCLUSION: The model that was implanted with artificial discs showed increased segmental motion and stress on the facet joints compared to the intact model. We hypothesize that the removal of the anterior longitudinal ligament is the major cause of increased segmental motion and stress on the facet joints in the implanted model. The development of new artificial discs should focus on compensating for these unwanted results.

Recycling of Cervical Artificial Disc for the Symptomatic Adjacent Segment Disorder Combined with Instability on Total Disc Replacement Area: A Case Report

The authors describe the revision case of a 58-year-old man who presented with pain in the neck and both shoulders after C4-5 cervical total disc replacement (C-TDR) and C5-6 anterior cervical discectomy and fusion (ACDF), and in whom there was evidence of instability with sagittal translation at the C4-5 TDR level and of a herniated cervical disc (HCD) at the left side of C3-4. The revision surgery was performed as follows: previous plate removal at the C5-6 level, artificial disc removal and ACDF at the C4-5 level with cage and previous plate insertion, and TDR at the C3-4 level using the previously implanted C4/5 artificial disc. If instability develops at the level of an artificial disc, we perform additional posterior fusion or anterior removal of the artificial disc and fusion. However, if we encounter combined adjacent segment disc disease, we may reuse the unstable segment artificial disc at the adjacent segment and perform salvage anterior fusion on the unstable segment. This is the first report issued on the management of instability after previous C-TDR involving a switch to ACDF and the use of new TDR at the adjacent level. Furthermore, we conceptually recommend a solution to an emerging problem of adjacent segment disease due to the heterotopic ossification(HO) after C-TDR.

Clinical and Radiographic Analysis of Cervical Total Disc Replacement Versus Anterior Cervical fusion using Stand-alone Cage

OBJECTIVE: Total intervertebral disc replacement is designed to preserve motion and avoid limitations of fusion after removing local pathology. The authors report the results of a signle-center study to determine functional and radi- ologic outcomes associated with cervical total disc replacement versus those of cervical fusion. METHODS: We retrospectively reviewed the charts and radiographs of patients who underwent a total intervertebral disc replacement(TDR) or a single-level anterior cervical fusion(ACDF) between January 1, 2004, and September 31, 2007. Clinical symptom was assessed using the Visual Analog Scale(VAS) of the neck and of the arm pain. Range of motion was determined by radiologic assessment of flexion-extension radiographs. Data were collected before surgery and at 6 weeks, 3, 6, 12, and 24 months after surgery. RESULT: A total of 125 patients were identified with 63 having TDR(43 males and 20 females) and 62 having fusion(42 males and 20 females). The average age was 49.1 years(TDR) and 51.7 years(ACDF)(p=0.229). The mean neck pain VAS before surgery was 6.52(TDR) and 6.61(ACDF)(p=0.732). At 2-year follow-up, the average neck pain VAS for the TDR group was 1.59 and ACDF 1.85(p=0.168). The mean arm pain VAS before surgery was 6.37(TDR) and 6.60(ACDF)(p=0.335). At 2 years: 1.41(TDR) and 1.65(ACDF)(P = 0.148). More motion(an average of 9.00 degrees at 24 months) was retained after surgery in the TDR group than the fusion group at the treatment level. There was no significant diffe- rence in motion at adjacent levels. CONCLUSION: Total disc replacement maintained physiological segmental motion at the 2-year follow-up. The finding that there was no statistically significant difference between the groups in motion at adjacent levels must be verified on further studies.

Surgical Outcome of Cervical Arthroplasty Using Bryan(R)

OBJECTIVE: Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of Bryan(R) cervical disc prosthesis. METHODS: The authors retrospectively reviewed radiographic and clinical outcomes in 52 patients who received the Bryan(R) Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of functional spine unit (FSU), and the C2-7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria, visual analogue pain scale (VAS) and neck disability index (NDI). RESULTS: A total of 71 Bryan(R) disc were placed in 52 patients. A single-level procedure was performed in 36 patients, a two-level procedure in 13 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria, and showed significant improvement by VAS and NDI score (p < 0.05). The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level (p < 0.05). 97% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 88.5% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 70% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 66.6% of the patients postoperatively. CONCLUSION: Arthroplasty using the Bryan(R) disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although the early results are promising, this is a relatively new approach, therefore long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.

Radiologic Comparison of Cervical Athroplasty with Cervical Arthrodesis

OBJECTIVE: The incidence of symptomatic adjacent segment disease appears to occur at a rate of 2% to 3% per year, following anterior cervical discectomy and fusion. Recently, cervical arthroplasty is a preferred procedure to arthrodesis. METHODS: We performed 16 arthropalsties form January 2005 to December 2006 in the Samsung medical center, using the BRYAN artificial disc and 16 anterior cervical interbody fusions. Radiographic evaluation included flexion and extension roentgenogram images of cervical spine. In the former group, the pre- and postoperative segmental sagittal range of motion(ROM) in the arthroplasty level and the adjacent level were measured. In the later group, the pre- and postoperative segmental sagittal ROM in the adjacent level to the fusion level was measured and the Cobb angles at C2-7(or 6) to ascertain overall cervical alignment was measured in both groups. RESULTS: There was minimal change in sagittal ROM of whole cervical spine in all patients in the two groups. Sagittal ROM of arthroplaty level were increased 7.581+/-4.222 to 11.512+/-5.398(p<0.05) ROM of adjacent level to arthroplasty level were no significant change pre- and postoperatively. But ROM of adjacent level to arthrodesis level were increased 7.160+/-3.609 to 11.260+/-4.832(p<0.05). CONCLUSIONS: Artificial disc could maintain ROM of pathologic level and adjacent level to fusion level should replace ROM of pathologic level but adjacent level to arthroplasty level should not replace additional ROM postoperatively. Long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.

Comparative Study of Two-Level Hybrid Surgery (Cervical Artificial Disc with Cage) with Two-Level Anterior Cervical Interbody Fusion for Multi-level Cervical Degenerative Disease

INTRODUCTION: Cervical anterior interbody fusion may be considered to be the gold standard for treatment of symptomatic cervical degenerative disc disease. However, this method leads to degenerative changes at the levels adjacent to the fused segments. On the other hand, multilevel cervical artificial disc replacement is another treatment for cervical degenerative disease, but the effectiveness and stability of artificial disc has not been proven yet. The purpose of this study is to compare the two-level hybrid surgery (Cervical disc prosthesis replacement at one level, and interbody fusion with cage at the other level) with the classical two-level interbody fusion in relation to the clinical outcomes and effects on the adjacent segment levels. METHOD: 27 patients with two-level cervical degenerative disease were enrolled and assigned to each study group. Radiologic analysis was used to measure the range of movement (ROM) of cervical spine, functional spinal unit (FSU) and adjacent segment levels at 2 months postoperatively and follow-up period (Mean follow-up period was 9.3(+/-4.1) month). Furthermore, clinical outcomes were analyzed by using visual analogue scale (VAS) and Odom..s criteria. RESULT: Out of 27 patients, 14 patients received hybrid surgery (group A) and 13 patients received two-level interbody fusion using a cage with bone graft (group B). Both groups showed significant improvement in symptoms and the VAS scores after operation (group A: from 8.2 to 2.4, group B: from 8.0 to 3.2). In group A, ROM of C2-7 decreased at 2 month postoperatively, but it was restored to nearly preoperative state during follow-up period. ROM of C2-7 in group B also showed similar changes, and there were no statistically significant difference between two groups (group A: pre-operation 44.3degrees, 2 months after operation 29.0degrees and last follow-up 41.6degrees, group B: pre-operation 46.8degrees, 2 months after operation 26.3degrees and last follow-up 37.4degrees). In both upper and lower segments, ROM of group B was significantly increased during follow-up period, compared with ROM of group A. This reflected that adjacent segments in group B received more stress due to bone fusion of functional spinal unit. CONCLUSION: The hybrid surgery was somewhat effective in two-level cervical degenerative disease. ROM analysis of adjacent segments in hybrid surgery group suggested that this group received less stress at adjacent segments, compared with two-level anterior cervical fusion group. Further follow-up study is required to assess long-term outcomes of the hybrid surgery and its influence on adjacent levels.

Surgical Management of Chronic Low Back Pain

Conservative therapy remains the mainstay treatment of chronic low back pain (LBP). If this has failed, surgical options may be considered in carefully selected patients. Still surgical treatment for chronic LBP is a matter of intensive and controversial discussions. Nevertheless, surgical management for chronic (LBP) has been evolved and increased gradually. Spinal fusion has been the established surgical option in cases that did not respond to conservative therapy. Besides spinal fusion, newer technologies such as artificial disc replacement, dynamic stabilization, and spinal cord stimulation are being increasingly considered. Although successful results of these procedures have been published, evidence-based data on the efficacy and benefits of most of these techniques are still lacking. However, empirical data show good or at least satisfactory clinical results of these procedures when they were applied under restrictive indication criteria. Further prospective randomized controlled studies are mandatory to determine the role of these procedures, and basic research is necessary to understand the pathogenesis of LBP at the molecular and genetic levels

Cervical artificial disc replacement in protection of adjacent segment discs / 中国矫形外科杂志

0.05).Measurement results of adjacent segment movement extention showed more significant changes in the fusion group than in the non-fusion group(P