Regenos spacers are not suitable for open-door laminoplasty because of serious adverse events caused by their insufficient mechanical strength

Noguchi, Hiroshi; Koda, Masao; Funayama, Toru; Kumagai, Hiroshi; Saito, Junya; Mannoji, Chikato; Aramomi, Masaaki; Abe, Tetsuya; Nagashima, Katsuya; Miura, Kousei; Mataki, Kentaro; Fuji, Kengo; Furuya, Takeo; Yamazaki, Masashi

doi:10.1016/j.jocn.2018.07.015

Cited by 13 publications

(12 citation statements)

References 11 publications

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“…Compared with spacer fixation, miniplate fixation reinforced with screws could reduce the risk of instrumentation-related complications and now is widely applied in clinical practice. [14,15] Usually, miniplates were introduced at all levels in EOLP. However, studies began to perform modified approaches to reduce the number of miniplates used due to the high costs.…”

Section: Discussionmentioning

confidence: 99%

Comparative effectiveness of all levels miniplate fixation versus a modified hybrid fixation in cervical expansive open-door laminoplasty

Yang

Liu²,

Lin³

et al. 2019

Medicine

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In this study, we first reported of a modified hybrid fixation method in expansive open-door laminoplasty (EOLP) in order to reduce medical costs. The purpose of the present study is to compare the surgical outcomes and cost-effectiveness of the modified fixation with all levels miniplate fixation in EOLP for multilevel cervical spondylotic myelopathy.Data of 67 patients who underwent EOLP from July 2015 to June 2016 were retrospectively analyzed, with 33 in the modified group and 34 in the all miniplate group based on their surgical approaches. Laminae were kept open with alternate levels miniplate and anchor fixation in the modified group, while with all levels miniplate fixation in the all miniplate group. Medical costs and clinical results including Japanese Orthopedic Association (JOA) scores, Visual Analogue Scale (VAS) scores and occurrences of complications were investigated and compared between the 2 groups. After evaluation on X-ray, CT, and MRI, radiographic data reflecting cervical alignments, spinal canal enlargement and spinal cord decompression were collected and compared within each group and between the 2 groups.After a follow-up period of about 18 months, no significant differences in operation time, intraoperative blood loss, complication rates, VAS scores, neurological recovery rates and postoperative hospital stays were observed between the 2 groups. However, EOLP with the modified fixation costed less. When comparing the 2 groups, cervical curvature index (CCIs) which reflected cervical alignments and anteroposterior diameters (APDs) reflecting spinal canal enlargement at all the follow-ups had no significant differences. Postoperative open angles which reflected spinal cord decompression of C4 and C6 were significantly smaller in the modified group. However, that difference was no longer detected at the final follow-up. Within each group, APDs increased significantly after surgery. However, no significant differences in CCIs and open angles at different follow-ups were observed in each group.Compared with all miniplate fixation, the modified hybrid fixation in EOLP showed almost the same clinical and radiographic results. However, the modified hybrid fixation method could reduce costs.

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Section: Discussionmentioning

confidence: 99%

Comparative effectiveness of all levels miniplate fixation versus a modified hybrid fixation in cervical expansive open-door laminoplasty

Yang

Liu²,

Lin³

et al. 2019

Medicine

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“…This showed no significant difference between the HA spacers (P = . 15) but was higher in high-porosity (50%) than low-porosity (35%) HA spacers throughout the study period. Meanwhile, spacer breakage was found in 4.7% of high-porosity (50%) HA spacers and 1.2% of low-porosity (35%) HA spacers (P = .37).…”

mentioning

confidence: 87%

“…13 The porosity of HA is related to its osteoconductive capability and mechanical strength, as HA with an increased porosity has a high osteoconductive capability 14 but also a relatively high risk of breakage. 15 However, no prospective studies have compared bone bonding and absorption in HA spacers with different types of porosity for cervical laminoplasty. The aim of the current study was to clarify the utility of increased porosity HA spacers for double-door laminoplasty by analyzing CT images.…”

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confidence: 99%

Improved bone bonding of hydroxyapatite spacers with a high porosity in a quantitative computed tomography‐image pixel analysis: A prospective 1‐year comparative study of the consecutive cohort undergoing double‐door cervical laminoplasty

Takeoka

Yurube

Maeno³

et al. 2020

JOR Spine

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Laminoplasty using hydroxyapatite (HA) spacers is widely performed in patients with cervical myelopathy. However, spacer dislocation is a critical complication caused by bone absorption and inadequate bone conductivity, and can result in dural damage and restenosis. We thus designed a prospective cohort study to clarify the feasibility of increased porosity HA spacers for double‐door laminoplasty by analyzing computed tomography (CT) images. Forty‐seven patients underwent cervical laminoplasty. Two different types of CERATITE HA spacer were used, either high porosity (50%) or low porosity (35%). These HA spacers were placed in an alternating manner into the laminae in each patient. In total, 85 high‐porosity (50%) HA spacers and 84 low‐porosity (35%) HA spacers were implanted. At postoperative 2 weeks, 3 months, 6 months, and 1 year, CT images were obtained. In both groups, the percentage of bone‐bonding boundary area of the HA spacer in contact with laminae and bone volume of the spinous process relative to the 2‐week value were calculated by a 3D and 2D CT‐image pixel analysis. The bone‐bonding ratio was significantly higher in high‐porosity (50%) than low‐porosity (35%) HA spacers at 3 months and thereafter (1 year, 69.3 ± 27.8% and 49.7 ± 32.9% respectively, P < .01). The bone volume in both groups significantly decreased with time (1 year, 73.2 ± 29.8% and 69.0 ± 30.4% respectively, P < .01), indicating bone absorption. This showed no significant difference between the HA spacers (P = .15) but was higher in high‐porosity (50%) than low‐porosity (35%) HA spacers throughout the study period. Meanwhile, spacer breakage was found in 4.7% of high‐porosity (50%) HA spacers and 1.2% of low‐porosity (35%) HA spacers (P = .37). In summary, high‐porosity (50%) HA spacers have the advantages of accelerated bone bonding and relatively decelerated bone absorption compared to low‐porosity (35%) HA spacers; however, possibly more frequent breakage of HA spacers with a high porosity (50%) requires careful, extended postoperative follow‐up.

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“…Although deformations (such as cracks, crushing, and wear) and changes in absorption were seen in 21% of cases, the clinical course was not affected [ 38 ]. On the other hand, we had reported that Regenos ® is not a suitable spacer for open-door laminoplasty since it has been damaged after surgery in many cases, some of which required reoperation [ 39 ].…”

Section: Clinical Applications Of Regenos ® ; Unidirectional Porous Hapmentioning

confidence: 99%

Unidirectional porous beta-tricalcium phosphate and hydroxyapatite artificial bone: a review of experimental evaluations and clinical applications

et al. 2021

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In Japan, where allograft bone transplantation is not widespread, prospects for artificial bones are very high. Therefore, artificial bones with various compositions, porous structures, and porosities have been developed and employed for clinical use. Both Affinos® and Regenos® (made of beta-tricalcium phosphate and hydroxyapatite, respectively) are artificial bones with a unique unidirectional porous structure, in which pores with a diameter suitable for tissue penetration (25–300 μm) are aligned in one direction. The unidirectional porous structure allows rapid penetration of blood deep into the materials by a capillary effect. In animal experiments, Affinos® showed well-balanced resorption and was replaced with the host’s own bone from an early stage after implantation and new bone formation and remodeling were observed in the cortical bone and medullary cavity. When implanted for clinical situation, resorption from an early stage and good replacement with the patient’s own bone were also observed. Regenos® has an internal osteon-like material and a vascular-like structure that is maintained within the pores even after long-term implantation, as noted in an animal experiment. When implanted for clinical situation, good osteoconductivity was observed from an early stage of implantation. In addition, the material was observed to be slowly absorbed over time in some cases. We have discussed the beneficial effects of combining teriparatide and platelet-rich plasma impregnation and the potential prospects of these artificial bones.

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Regenos spacers are not suitable for open-door laminoplasty because of serious adverse events caused by their insufficient mechanical strength

Cited by 13 publications

References 11 publications

Comparative effectiveness of all levels miniplate fixation versus a modified hybrid fixation in cervical expansive open-door laminoplasty

Comparative effectiveness of all levels miniplate fixation versus a modified hybrid fixation in cervical expansive open-door laminoplasty

Improved bone bonding of hydroxyapatite spacers with a high porosity in a quantitative computed tomography‐image pixel analysis: A prospective 1‐year comparative study of the consecutive cohort undergoing double‐door cervical laminoplasty

Unidirectional porous beta-tricalcium phosphate and hydroxyapatite artificial bone: a review of experimental evaluations and clinical applications

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