Multilevel Cervical Fusion and Its Effect on Disc Degeneration and Osteophyte Formation

Lopez-Espina, Carlos G.; Amirouche, Farid; Havalad, Vinod

doi:10.1097/01.brs.0000215205.66437.c3

Cited by 113 publications

(72 citation statements)

References 23 publications

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“…Consistent with other results reported in the literature, 3,4,6,10,50 the current study noted higher biomechanical changes above the fused segments. A few biomechanical investigations have also shown greater disc stress (or pressure) and motion changes at the inferior levels than at the superior levels in 1-and 2-level cervical fusions, 26,39 whereas no significant 22,41,43 or even decreased 45 biomechanical changes have been recorded at the adjacent segments after 1-level cervical arthrodesis.…”

Section: Discussionmentioning

confidence: 99%

“…inside the discs above and below the level of corpectomy and/or discectomy and fusion. Lopez-Espina et al 26 investigated 1-and 2-level discectomy and fusions with standalone bone grafts using a FE model, and demonstrated an increase in adjacent-level disc stress in flexion, axial rotation, and lateral bending, but not in extension. We have shown a step further that the biomechanical changes at adjacent segments are not limited solely to the discs, but also propagate to the posterior facets.…”

Section: Discussionmentioning

confidence: 99%

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Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Hussain

Nassr

Natarajan

et al. 2014

SPI

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Object Biomechanical studies have shown that anterior cervical fusion construct stiffness and arthrodesis rates vary with different reconstruction techniques; however, the behavior of the adjacent segments in the setting of different procedures is poorly understood. This study was designed to investigate the adjacent-segment biomechanics after 3 different anterior cervical decompression and fusion techniques, including 3-level discectomy and fusion, 2-level corpectomy and fusion, and a corpectomy-discectomy hybrid technique. The authors hypothesized that biomechanical changes at the segments immediately superior and inferior to the multilevel fusion would be inversely proportional to the number of fused bone grafts and that these changes would be related to the type of fusion technique. Methods A previously validated 3D finite element model of an intact C3–T1 segment was used. Three C4–7 fusion models were built from this intact model by varying the number of bone grafts used to span the decompression: a 1-graft model (2-level corpectomy), a 2-graft model (C-5 corpectomy and C6–7 discectomy), and a 3-graft model (3-level discectomy). The corpectomy and discectomy models were also previously validated and compared well with the literature findings. Range of motion, disc stresses, and posterior facet loads at the segments superior (C3–4) and inferior (C7–T1) to the fusion construct were assessed. Results Motion, disc stresses, and posterior facet loads generally increased at both of the adjacent segments in relation to the intact model. Greater biomechanical changes were noted in the superior C3–4 segment than in the inferior C7–T1 segment. Increasing the number of bone grafts from 1 to 2 and from 2 to 3 was associated with a lower magnitude of biomechanical changes at the adjacent segments. Conclusions At segments adjacent to the fusion level, biomechanical changes are not limited solely to the discs, but also propagate to the posterior facets. These changes in discs and posterior facets were found to be lower for discectomy than for corpectomy, thereby supporting the current study hypothesis of inverse relationship between the adjacent-segment variations and the number of fused bone grafts. Such changes may go on to influence the likelihood of adjacent-segment degeneration accordingly. Further studies are warranted to identify the causes and true impact of these observed changes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Hussain

Nassr

Natarajan

et al. 2014

SPI

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“…Many authors have noted that the biomechanical effects on the adjacent segments are greater after the fusion of multiple segments. 8,18 One possible reason for our results is the greater stress at the skip levels in the fusion group compared with that in arthroplasty group.…”

Section: Discussionmentioning

confidence: 73%

Clinical and radiological results of two hybrid reconstructive techniques in noncontiguous 3-level cervical spondylosis

Kan¹,

Kang²,

Gao³

et al. 2014

SPI

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Object To date, formulation of the optimal surgical protocol for noncontiguous multilevel cervical spondylosis remains controversial, and the corresponding clinical data continue to be limited. The purpose of this study was to compare the clinical and radiological outcomes of two hybrid reconstructive techniques in noncontiguous 3-level cervical spondylosis (2 contiguous disc levels and 1 “skip” disc level [nonoperated level between 2 operated levels]). The incidence of adjacent-segment degeneration (ASD) was also evaluated. Methods Sixty-three consecutive patients with noncontiguous 3-level cervical spondylosis who underwent two different hybrid methods of treatment were retrospectively reviewed. The patients were divided into 2 groups, the fusion group and the arthroplasty group. A titanium mesh cage and an anterior cervical plate were used after the anterior cervical corpectomy, and then a stand-alone cage (the fusion group) or an artificial cervical disc (the arthroplasty group) was used after the discectomy. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scale score and the JOA scale score improvement rate preoperatively and during follow-up. Radiological results were assessed using global angle and global range of motion (ROM) of the cervical spine. The ASD was also evaluated. Results The JOA scores of the patients significantly improved postoperatively and were well maintained within the follow-up period, as did the JOA scale score improvement rate. The mean global angle of the cervical spine of the patients significantly increased postoperatively. At the last follow-up evaluation, the mean global ROM was retained by patients in the arthroplasty group (p > 0.05) but not by patients in the fusion group (p = 0.00). There was no significant difference in the incidence of ASD between the 2 groups (p = 0.114). However, at the skip levels, patients in the fusion group had a higher incidence of ASD than patients in the arthroplasty group (p = 0.038). Conclusions Both of the hybrid procedures (anterior cervical corpectomy and fusion [ACCF] + anterior cervical discectomy and fusion, and ACCF + cervical disc arthroplasty [CDA]) yielded favorable clinical and radiological outcomes in the treatment of noncontiguous 3-level cervical spondylosis. Moreover, the ACCF + CDA procedure may have the ability to decrease the likelihood of ASD in appropriate patients.

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“…This technique is reportedly associated with overall rates of satisfaction ranging from 70% to 99% depending on type of grading scale [8,12,34,36,41,46]. When one cervical segment is fused, the adjacent cervical levels provide compensatory motion, thus increasing the mechanical stress of these sites [9,18,20,25,33,39]. Degenerative changes in intervertebral spaces adjacent to the fused segment can present in 10% to 89% of operated patients at long-term followup [23,26,33,37,52].…”

Section: Introductionmentioning

confidence: 99%

“…When one cervical segment is fused, the adjacent cervical levels provide compensatory motion, thus increasing the mechanical stress of these sites [9,18,20,25,33,39]. Degenerative changes in intervertebral spaces adjacent to the fused segment can present in 10% to 89% of operated patients at long-term followup [23,26,33,37,52]. Several authors have reported progression of adjacent degeneration relates to a number of factors: large ranges of movements, individual predisposition, life habits, increased stress on the disc space of the adjacent level degeneration, reduction of the disc nutrition because of the increased stress on the end plates, increased motion transferred to fewer remaining motion segment, and instability [1,18,23,30,33,37].…”

Section: Introductionmentioning

confidence: 99%

Sagittal Segmental Alignment as Predictor of Adjacent-Level Degeneration After a Cloward Procedure

Faldini

Pagkrati

Leonetti

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background The Cloward anterior interbody fusion is commonly performed for cervical disc herniation or spondylosis. In followup studies, various authors have noted clinically relevant adjacent-level degeneration. However, factors associated with adjacent-level degeneration are not well known. Questions/purposes We asked whether the postoperative sagittal segmental alignment of the fused vertebrae could be used as a predictor of adjacent-level degeneration. Methods We retrospectively studied 107 patients, aged 35 to 55 years, with one-level cervical disc disease between C4 and C7 operated on from 1985 to 1995 by discectomy and one-level anterior cervical fusion according to the Cloward procedure. In standard radiographs of the cervical spine in lateral view, the alignment of the involved intervertebral space (sagittal segmental alignment) and the sagittal alignment of the cervical spine were measured and the adjacent-level degeneration was assessed using the Kellgren and Lawrence criteria. The minimum followup was 10 years (mean, 16 years; range, 10-23 years).

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Multilevel Cervical Fusion and Its Effect on Disc Degeneration and Osteophyte Formation

Abstract: The results of this study quantify the significant increase in the level of stresses below and above the fused segments in the cervical spine. A sustained level of this stress can lead to further discs degeneration and osteophytes.

Cited by 113 publications

References 23 publications

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Relationship between biomechanical changes at adjacent segments and number of fused bone grafts in multilevel cervical fusions: a finite element investigation

Clinical and radiological results of two hybrid reconstructive techniques in noncontiguous 3-level cervical spondylosis

Sagittal Segmental Alignment as Predictor of Adjacent-Level Degeneration After a Cloward Procedure

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