Evidence Of Adjacent Segment Degeneration Research Articles

Ten-year clinical and radiographic results of computer-assisted cervical pedicle screw fixation combined with laminoplasty

ObjectiveCervical pedicle screw (CPS) fixation is widely used for the treatment of cervical spinal instability from various causes; however, there are few reports on the long-term outcomes of this procedure. The present study evaluated the 10-year results of CPS fixation for cervical instability. MethodsThe medical records of 13 consecutive patients who underwent computer-guided CPS fixation for cervical instability were reviewed. The mean observation period was 153 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 and 10 years afterwards. Visual analog scale (VAS) scores for neck pain and radiological evidence of adjacent segment degeneration (ASD) at 10 years of follow-up were also assessed. ResultsMean JOA score significantly improved from 9.4 points before surgery to 13.2 points at 5 years after surgery (p < 0.001), followed next by a slight reduction to 11.6 points at 10 years postoperatively. C2-7 lordotic angle tended to decrease from 7.9° preoperatively to 5.3° at 10 years after surgery. No clinically significant complications, such as neurovascular injury caused by screw misplacement, were observed. The mean VAS score for neck pain was 31.7 points at the study endpoint, and ASD rate was 23.1%. ConclusionsAt 10 years after CPS fixation, mean JOA score was improved without symptoms indicative of cervical myelopathy recurrence. Our long-term results confirm that computer-assisted CPS fixation is useful for treating cervical instability.

Motion analysis of dynamic cervical implant stabilization versus anterior discectomy and fusion: a retrospective analysis of 70 cases.

Retrospective kinematic analysis of treated level, adjacent levels, and overall cervical spine after single-level dynamic cervical implant (DCI) stabilization versus anterior cervical discectomy and fusion (ACDF). Between June 2009 and March 2013, 70 consecutive patients with a symptomatic single-level cervical degenerative disk disease (DDD) were enrolled in this study and divided into DCI (n = 35) group and ACDF (n = 35) group. All cases were followed up for more than 5years. The study compared perioperative parameters; clinical outcomes; and radiological parameters. Kinematic analysis included range of motion (ROM) of treated level and adjacent level, overall ROM (C2-C7), and changes in adjacent disk spaces. There were no significant differences between the DCI group and ACDF group in terms of improvement in the SF-36, VAS, NDI, and JOA scores. DCI stabilization resulted in better ROM of C2-C7 and the treated level than ACDF did. The ROM of treated level decreased significantly at 24months after surgery and last follow-up in the DCI group, and the C2-C7 ROM showed different degrees of reduction after the 24months after surgery. Radiological evidence of adjacent segment degeneration (ASD) at last follow-up was observed in 4/22 patients (18.2%) in the DCI group and 5/23 patients (21.7%) in the ACDF group which was not a significant difference between groups (p > 0.05). DCI stabilization for the treatment of cervical DDD cannot preserve the normal kinematics of the cervical spine for a long time, especially the treated level. DCI stabilization cannot decrease the risk of ASD compared with ACDF. These slides can be retrieved under Electronic Supplementary Material.

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 50.9years [range, 33–68years]) with cervical DDD who underwent surgery and were followed for more than 2years were enrolled in this study (mean 31.1months, range 24–47months). 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 3months after surgery to final follow-up the DHI showed a significant reduction comparing 1week after surgery (all p<0.05). The fusion rates were 91.7% (66/72) and the radiologic mean fusion time was 9.9months. 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.

Mid-term results of computer-assisted cervical pedicle screw fixation.

Study DesignA retrospective study.PurposeThe present study aimed to evaluate mid-term results of cervical pedicle screw (CPS) fixation for cervical instability.Overview of LiteratureCPS fixation has widely used in the treatment of cervical spinal instability from various causes; however, there are few reports on mid-term surgical results of CPS fixation.MethodsRecord of 19 patients who underwent cervical and/or upper thoracic (C2-T1) pedicle screw fixation for cervical instability was reviewed. The mean observation period was 90.2 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 years after surgery. Postoperative computerized tomography was used to determine the accuracy of screw placement. Visual analog scale (VAS) for neck pain and radiological evidence of adjacent segment degeneration (ASD) at the 5-year follow-up were also evaluated.ResultsMean JOA score was significantly improved from 9.0 points before surgery to 12.8 at 5 years after surgery (p=0.001). The C2-7 lordotic angle of the neutral position improved from 6.4° to 7.8° at 5 years after surgery, but this was not significant. The major perforation rate was 5.0%. There were no clinically significant complications such as vertebral artery injury, spinal cord injury, or nerve root injury caused by any screw perforation. Mean VAS for neck pain was 49.4 at 5 years after surgery. The rate of ASD was 21.1%.ConclusionsOur mid-term results showed that CPS fixation was useful for treating cervical instability. Severe complications were prevented with the assistance of a computed tomography-based navigation system.

Skip-level Anterior Cervical Discectomy and Fusion With Self-locking Stand-alone PEEK Cages for the Treatment of 2 Noncontiguous Levels of Cervical Spondylosis

Retrospectively study. To evaluate clinical and radiologic outcomes of skip-level anterior cervical discectomy and fusion (ACDF) with self-locking stand-alone polyetheretherketone (PEEK) cages for the treatment of 2 noncontiguous levels of cervical disk degenerative disease (CDDD). The use of stand-alone PEEK cages in ACDF has been proved to be safe and effective to treat CDDD. For 2 noncontiguous levels of CDDD, skip-level ACDF with self-locking stand-alone PEEK cages, which fuses only the involved levels without anterior plates, may be the optimal treatment choice. Sixteen consecutive patients with 2 noncontiguous levels of CDDD underwent skip-level ACDF with self-locking stand-alone PEEK cages. Clinical outcomes were evaluated using Japanese Orthopaedic Association scores and Odom criteria. Fusion rate and time, cages subsidence, spinal curvature, intervertebral height at the operated level, and adjacent disk degeneration were assessed. Patients were followed up for average 43.6 months (range, 24-78 mo). The mean operative time was 113 minutes (range, 98-134 min) with an average blood loss of 62 mL (range, 47-76 mL). The Japanese Orthopaedic Association score, degree of spinal curvature, and intervertebral height were significantly increased at the final follow-up examination compared with preoperatively (P<0.05). Fifteen patients (93.8%) achieved solid fusion in an average time of 5.1 months. Three cages (9.38%) in 2 patients subsided. Radiologic evidence of adjacent segment degeneration was observed in 3 segments (6.25%; 2 infra-adjacent segments and 1 intermediate segment). No case had neurological deterioration postoperatively. No implant failure or migration was observed during follow-up. Treatment of 2 noncontiguous levels of CDDD with skip-level ACDF with self-locking stand-alone cages achieved good clinical and radiologic outcomes including a high fusion rate, low complication rate, and excellent maintenance of spinal curvature and intervertebral height.

Symptomatic adjacent segment disease after cervical total disc replacement: re-examining the clinical and radiological evidence with established criteria

Although several publications in the last decade have proved equality in safety and efficacy of the total disc replacement (TDR) to the anterior fusion procedure in cervical spine, the claim that TDR may reduce the incidence of adjacent segment disease (ASD) has not been corroborated by clinical evidence. We attempt to predict the true incidence of symptomatic ASD after TDR surgery in the cervical spine at one or two levels at a median follow-up period of 4 years. A total of 763 patients were screened to participate in four different Food and Drug Administration device exemption trials for artificial cervical disc replacement at three collaborating institutions. Two hundred seventy-one patients qualified and enrolled in the trials. One hundred seventy-three randomized to receive artificial disc replacement surgery, and 167 have completed a 4-year or longer follow-up. Patients experiencing cervical radiculopathy symptoms in the follow-up period were worked-up with clinical examinations, magnetic resonance imaging of the cervical spine, and other diagnostic studies. Once a clinical correlation was established with the imaging evidence of adjacent segment degeneration, a careful record was maintained to document the subsequent medical and/or surgical treatment received by these patients. Statistical analysis was performed to determine the true incidence of and factors affecting the ASD after cervical disc replacement in these patients. Twenty-six patients (15.2%) were identified to satisfy our criteria for ASD at the median follow-up of 51 months, with the annual incidence of 3.1% as calculated by life tables. The actuarial 5-year freedom from ASD rate was 71.6%±0.6%, and the mean period for freedom from ASD was 70.4±2.1 months. The incidence of symptomatic ASD after cervical TDR is 3.1% annually regardless of the patient's age, sex, smoking habits, and design of the TDR device. The presence of osteopenia and lumbar degenerative disease significantly increase the risk of developing ASD after anterior cervical surgery.

Eight-Year Clinical and Radiological Follow-Up of the Bryan Cervical Disc Arthroplasty

Single institution, prospective cohort study of 21 patients who underwent single- or bilevel cervical disc arthroplasty for radiculopathy. To evaluate the long-term outcome of cervical disc arthroplasty. There is an increasing trend in the use of cervical arthroplasty; however, no long-term outcome studies exist to verify their safety, functionality, and durability. A total of 21 patients underwent 27 total disc arthroplasties using the Bryan cervical disc (Medtronic Sofamor Danek Inc, Memphis, TN) after anterior cervical discectomy. Clinical and radiological data were obtained from the 8-year postoperative review. Nineteen of twenty-one patients were able to perform daily activities without limitation. Twenty of twenty-one patients reported fair to excellent outcome according to Odom criteria and 21 of 27 (78%) operated segments were mobile. Functional prostheses moved an average of 10.6°, which was similar to the range of movement of the adjacent nonoperated segments of the cervical spine. Heterotopic ossification was evident in 13 of the 27 (48%) operated segments and restricted movement of the prosthesis in nine cases. Five of the six patients who received bilevel arthroplasties developed heterotopic ossification. There was one case of posterior migration of the prosthesis, which did not have any clinical repercussion. No other case showed evidence of migration, subsidence, loosening, or wear. Radiological evidence of adjacent segment degeneration was observed in four patients (19%); however, each of these patients had pre-existing degenerative disc disease at these levels on preoperative imaging. At 8-year follow-up, the Bryan cervical disc arthroplasty maintains favorable clinical and radiological results, with preservation of movement and satisfactory clinical outcome in the majority of cases. However, the incidence of heterotopic ossification causing restricted range of movement of the prosthesis appears to increase with time, especially in bilevel procedures.

Assessment of adjacent-segment degeneration in and between patients treated with anterior or posterior cervical simple discectomy.

The authors compared the incidence of radiologically documented and/or symptomatic adjacent segment degeneration in and between patients who underwent anterior or posterior single-level, simple discectomy. 79 patients were clinically and radiologically examined for adjacent segment degeneration (ASD). The results were compared to evaluate which approach was predominant for adjacent segment disc degeneration. ASD was found in 57 of a total of 79 patients. 24% of the patients demonstrated clinical and radiographic evidence and 48% of the patients demonstrated only radiographic evidence of ASD. Both anterior and posterior single level simple discectomy had similar rates for adjacent segment disease (p>0.05) . ASD was found to appear earlier in patients who had anterior cervical discectomy (4.78 vs 9.85 years, p:0.005). Symptomatic evidence of ASD was found to start earlier than radiological evidence of ASD (4.67 vs 7.63 years p:0.003). Radiographic evidence of adjacent segment degeneration was observed more commonly compared to symptomatic evidence of ASD (38 vs 19 patients p:0.002). Although, radiographic and clinical evidence of ASD is inevitable for both simple cervical discectomy procedures, neither anterior nor posterior simple cervical discectomy is the predominant approach for causing ASD.

Adjacent Segment Disease in a Patient With Klippel-Feil Syndrome and Radiculopathy: Surgical Treatment With Two-Level Disc Replacement: Case report

Klippel-Feil syndrome (KFS) is a complex congenital condition characterized by improper segmentation of cervical motion segments that could contribute to undesirable adjacent segment degeneration. KFS patients have a strong tendency to present with disease in the adjacent segments. When this condition is present, anterior decompression followed by total disc replacement can be performed safely and can lead to good clinical results. This treatment has theoretical advantages compared with anterior decompression and fusion. Comparative studies and long-term follow-up are needed. Complications associated with fusion include loss of a motion segment, disc height loss, subsidence of the graft, progressive degenerative changes at the adjacent level, graft-related complications, and graft-site complications. Such new technologies as motion preservation spine arthroplasty represent attempts to avoid these complications. Here we present a case report of a 62-year-old female patient with type I congenital fusion at the C5–6 level, with a history of neck pain and right radiculopathy at C5–7. X-rays and MRI show evidence of adjacent segment degeneration at levels above and below congenital fusion. The patient's preoperative visual analog score (VAS) for neck pain was 7 out of a possible 10, her score for right upper extremity pain was 8 out of 10, and her Neck Disability Index (NDI) was 32%. Surgical treatment consisted of anterior decompression and total disc replacement at both levels. At 1-year follow-up, the patient's VAS for neck pain was 2 out of 10, her VAS score for right upper extremity pain was 1 of 10, and her NDI was 9%.

Adjacent Segment Disease in a Patient With Klippel-Feil Syndrome and Radiculopathy: Surgical Treatment With Two-Level Disc Replacement

Klippel-Feil syndrome (KFS) is a complex congenital condition characterized by improper segmentation of cervical motion segments that could contribute to undesirable adjacent segment degeneration. KFS patients have a strong tendency to present with disease in the adjacent segments. When this condition is present, anterior decompression followed by total disc replacement can be performed safely and can lead to good clinical results. This treatment has theoretical advantages compared with anterior decompression and fusion. Comparative studies and long-term follow-up are needed. Complications associated with fusion include loss of a motion segment, disc height loss, subsidence of the graft, progressive degenerative changes at the adjacent level, graft-related complications, and graft-site complications. Such new technologies as motion preservation spine arthroplasty represent attempts to avoid these complications.Here we present a case report of a 62-year-old female patient with type I congenital fusion at the C5–6 level, with a history of neck pain and right radiculopathy at C5–7. X-rays and MRI show evidence of adjacent segment degeneration at levels above and below congenital fusion. The patient's preoperative visual analog score (VAS) for neck pain was 7 out of a possible 10, her score for right upper extremity pain was 8 out of 10, and her Neck Disability Index (NDI) was 32%. Surgical treatment consisted of anterior decompression and total disc replacement at both levels. At 1-year follow-up, the patient's VAS for neck pain was 2 out of 10, her VAS score for right upper extremity pain was 1 of 10, and her NDI was 9%.

Segmental Motion Adjacent to an Instrumented Lumbar Fusion

We present an in vitro biomechanical comparison of adjacent segment motion at the cranial segment (L3-L4) for an L4-L5 versus an L4-S1 fusion model using cadaveric lumbosacral spines. The purpose is to determine the biomechanical effect on the unfused cranial segment of extending a short lumbar fusion to the sacrum versus stopping at L5. Radiographic evidence of adjacent segment degeneration can occur as a late sequela in patients following lumbar and lumbosacral spinal fusions. It is believed that altered biomechanics adjacent to the fusion construct contribute to these degenerative changes. Little is known regarding changes in cranial adjacent segment mechanics resulting from inclusion of the sacrum compared to ending a fusion at L5. Seven human cadaveric lumbosacral spines were instrumented with pedicle screws at L4, L5, and S1. Rods were placed from L4-L5 and from L4-S1 to simulate the corresponding fusion models. A material testing system was used to apply load-controlled moments to the spines in flexion-extension, lateral bending, and axial rotation. Electromagnetic sensors were used to record 6 df motion across the L3-L4, L4-L5, and L5-S1 motion segments. Angular displacements were recorded and system stiffness was calculated for each spine and construct. A paired sample t test was used to determine significance of recorded differences. Under flexion-extension loading, the angular displacement in the sagittal plane at L3-L4 for the L4-S1 model was 9.0 degrees compared to 7.8 degrees for the L4-L5 model (+15%; P = 0.002). Under lateral bending loading, L3-L4 motion in the coronal plane for the L4-S1 model was 12.8 degrees and was 14.5 degrees for the L4-L5 model (-12%; P = 0.002). In axial rotation testing, L3-L4 torsional motion for the L4-S1 model was equivalent to the L4-L5 model. Overall system stiffness increased for the L4-S1 model compared with the L4-L5 model. In this load-controlled model, extending fusion across L5-S1 did not consistently increase motion at L3-L4. While it may be difficult to translate this finding to a clinical setting, avoiding fusion to the sacrum in a lower lumbar fusion may not provide significant benefit from the standpoint of avoiding adjacent segment disease.

Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion.

Adjacent segment degeneration following lumbar spine fusion remains a widely acknowledged problem, but there is insufficient knowledge regarding the factors that contribute to its occurrence. The aim of this study is to analyse the relationship between abnormal sagittal plane configuration of the lumbar spine and the development of adjacent segment degeneration. Eighty-three consecutive patients who underwent lumbar fusion for degenerative disc disease were reviewed retrospectively. Patients with spondylolytic spondylolisthesis and degenerative scoliosis were not included in this study. Mean follow-up period was 5 years. Results were analysed to determine the association between abnormal sagittal configuration and post operative adjacent segment degeneration. Thirty-one out of 83 patients (36.1%) showed radiographic evidence of adjacent segment degeneration. Patients with normal C7 plumb line and normal sacral inclination in the immediate post operative radiographs had the lowest incidence of adjacent level change compared with patients who had abnormality in one or both of these parameters. The difference was statistically significant (P<0.02). There was no statistically significant difference in the incidence of adjacent level degeneration between male and female patients; between posterior fusion alone and combined posterolateral and posterior interbody fusions; and between fusions extending down to the sacrum and fusions stopping short of the sacrum. It was concluded was that normality of sacral inclination is an important parameter for minimizing the incidence of adjacent level degeneration. Retrolisthesis was the most common type of adjacent segment change. Patients with post operative sagittal plane abnormalities should preferably be followed-up for at least 5 years to detect adjacent level changes.