Strain on Intervertebral Discs After Anterior Cervical Decompression and Fusion

Matsunaga, Shunji; Kabayama, Sukeaki; Yamamoto, Takuya; Yone, Kazunori; Sakou, Takashi; Nakanishi, Kenji

doi:10.1097/00007632-199904010-00011

Cited by 340 publications

(190 citation statements)

References 22 publications

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“…Many previous studies tried to figure out the reason of ASD after cervical arthrodesis, and biomechanical studies have shown evidence of hypermobility and increased stress at levels adjacent to the site of fused segment [20,21]. However, Matsunaga et al [22] calculated that there was no increase in the strain adjacent to a single-level ACDF, and Hilibrand et al [1] reported a reduced rate of adjacent segment disease in patients who underwent multilevel fusion compared with those treated by singlelevel fusion and a more likelihood of ASD in older patients. They also insisted that symptomatic adjacent segment disease is the result of progressive cervical spondylosis and is not caused by the arthrodesis itself [1,23].…”

Section: Discussionmentioning

confidence: 99%

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

et al. 2012

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Purpose It is well known that arthrodesis is associated with adjacent segment degeneration (ASD). However, previous studies were performed with simple radiography or CT. MRI is most sensitive in assessing the degenerative change of a disc, and this is the first study about ASD by radiography, CT and MRI. We sought to factors related to ASD at cervical spine by an MRI and CT, after anterior cervical spine surgery. Materials and methods This is a retrospective crosssectional study of cervical disc herniation. Patients of cervical disc herniation with only radiculopathy were treated with either arthroplasty (22 patients) or ACDF with cage alone (21 patients). These patients were required to undergo MRI, CT and radiography preoperatively, as well as radiography follow-up for 3 months and 1 year, and we conducted a cross-sectional study by MRI, CT and radiography including clinical evaluations 5 years after. Clinical outcomes were assessed using VAS and NDI. The fusion rate and ASD rate, and radiologic parameters (cervical lordosis, operated segmental height, C2-7 ROM, operated segmental ROM, upper segmental ROM and lower segmental ROM) were measured. Results The study groups were demographically similar, and substantial improvements in VAS (for arm) and NDI (for neck) scores were noted, and there were no significant differences between groups. Fusion rates were 95.2 % in the fusion group and 4.5 % in the arthroplasty group. ASD rates of the fusion and arthroplasty groups were 42.9 and 50 %, respectively. Among the radiologic parameters, operated segmental height and operated segmental ROM significantly decreased, while the upper segmental ROM significantly increased in the fusion group. In a comparative study between patients with ASD and without ASD, the clinical results were found to be similar, although preexisting ASD and other segment degeneration were significantly higher in the ASD group. C2-7 ROM was significantly decreased in ASD group, and other radiologic parameters have no significant differences between groups. Conclusion The ASD rate of 46.5 % after ACDF or arthroplasty, and arthroplasty did not significantly lower the rate of ASD. ASD occurred in patients who had preexisting ASD and in patients who also had other segment degeneration. ASD may be associated with a natural history of cervical spondylosis rather than arthrodesis.

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Section: Discussionmentioning

confidence: 99%

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

et al. 2012

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“…Some authors [15,29] have reported an increased risk of accelerated degeneration of adjacent segments after spinal fusion, with the risk of deterioration of the outcome with long-term follow-up. Gore and Sepic [9] reported that about one third of the patients had recurrent pain after a pain free period after ACDF.…”

mentioning

confidence: 99%

Long-term randomised comparison between a carbon fibre cage and the Cloward procedure in the cervical spine

2006

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“…Anterior-posterior translation during flexion/ extension is an important factor in determining shear strain in the anterior-posterior direction. Matsunaga et al [18] estimated shear strain at the adjacent levels after ACDF and found increased shear strain at the adjacent to two-or three-level ACDF, while no increases in shear strain were found at the adjacent level to the single-level ACDF. It should be noted that calculation of strain in the intervertebral disc requires even higher accuracy than the measurement of translation in the anterior-posterior direction since strain calculation requires measurement of the translation in the disc height direction at the same time.…”

Section: Discussionmentioning

confidence: 99%

“…In vivo kinematic studies using flexion/extension plain radiograms have also addressed the effects of anterior cervical fusion on the kinematics at the adjacent levels to fusion [4,8,[15][16][17][18][19][20][21][22]. Results of these studies were also variable.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional kinematic analysis of the cervical spine after anterior cervical decompression and fusion at an adjacent level: a preliminary report

et al. 2011

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Purpose Development of adjacent segment degeneration following anterior cervical decompression and fusion (ACDF) is still controversial, as adjacent-level kinematics is poorly understood. This study reports preliminary data from a high-accuracy 3D analysis technique developed for in vivo cervical kinematics. Methods From nine cervical spondylosis patients, four underwent single-level ACDF, and five underwent two-level ACDF using cylindrical titanium cage implant(s). Pre-and post-surgical CT scans were taken in flexion, neutral and extended positions, allowing us to compute segmental ranges of motion for rotation and translation, and 3D disc-height distributions. Differences in segmental motions and disc-height between fused and adjacent levels were analyzed with a Wilcoxon signed-rank test. Results are presented as mean ± SEM. Results The flexion/extension angular-ROM at the fusion level decreased after surgery (7.46 ± 1.17°vs. 3.14 ± 0.56°, p \ 0.003). The flexion/extension angular-ROM at one caudal adjacent level to the fusion level (3.97 ± 1.29°) tended to be greater post-operatively (6.11 ± 1.44°, p = 0.074). Translation in the anterior-posterior direction during flexion/ extension at the fusion level decreased after surgery (1.22 ± 0.20 mm vs. 0.32 ± 0.11 mm, p \ 0.01). No differences were found in adjacent-level disc heights between both study time-points. Conclusions This study showed increased segmental motion in flexion/extension angular-ROM at one level adjacent to ACDF. However, increases in the rotational angular-ROM were not statistically significant when cranial/caudal adjacent levels were analyzed separately. This preliminary study highlighted the capabilities of a 3D-kinematic analysis method to detect subtle changes in kinematics and disc height at the adjacent levels to ACDF. Thus, reliable evidence related to ACDF's influence on adjacent-level cervical kinematics can be collected.

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Strain on Intervertebral Discs After Anterior Cervical Decompression and Fusion

Abstract: Close attention should be paid to long-term biomechanical changes in the unfused segment.

Cited by 340 publications

References 22 publications

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

Long-term randomised comparison between a carbon fibre cage and the Cloward procedure in the cervical spine

Three-dimensional kinematic analysis of the cervical spine after anterior cervical decompression and fusion at an adjacent level: a preliminary report

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