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Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep

Background and Objectives: Spinal fusion is an effective and widely accepted intervention. However, complications such as non-unions and hardware failures are frequently observed. Radiologic imaging and physical examination are still the gold standards in the assessment of spinal fusion, despite mul...

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Autores principales: Windolf, Markus, Heumann, Maximilian, Varjas, Viktor, Constant, Caroline, Ernst, Manuela, Richards, Robert Geoff, Wilke, Hans-Joachim, Benneker, Lorin Michael
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9319051/
https://www.ncbi.nlm.nih.gov/pubmed/35888618
http://dx.doi.org/10.3390/medicina58070899
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author Windolf, Markus
Heumann, Maximilian
Varjas, Viktor
Constant, Caroline
Ernst, Manuela
Richards, Robert Geoff
Wilke, Hans-Joachim
Benneker, Lorin Michael
author_facet Windolf, Markus
Heumann, Maximilian
Varjas, Viktor
Constant, Caroline
Ernst, Manuela
Richards, Robert Geoff
Wilke, Hans-Joachim
Benneker, Lorin Michael
author_sort Windolf, Markus
collection PubMed
description Background and Objectives: Spinal fusion is an effective and widely accepted intervention. However, complications such as non-unions and hardware failures are frequently observed. Radiologic imaging and physical examination are still the gold standards in the assessment of spinal fusion, despite multiple limitations including radiation exposure and subjective image interpretation. Furthermore, current diagnostic methods only allow fusion assessment at certain time points and require the patient’s presence at the hospital or medical practice. A recently introduced implantable sensor system for continuous and wireless implant load monitoring in trauma applications carries the potential to overcome these drawbacks, but transferability of the principle to the spine has not been demonstrated yet. Materials and Methods: The existing trauma sensor was modified for attachment to a standard pedicle-screw-rod system. Two lumbar segments (L2 to L4) of one Swiss white alpine sheep were asymmetrically instrumented. After facetectomy, three sensors were attached to the rods between each screw pair and activated for measurement. The sheep was euthanized 16 weeks postoperatively. After radiological assessment the spine was explanted and loaded in flexion-extension to determine the range of motion of the spinal segments. Sensor data were compared with mechanical test results and radiologic findings. Results: The sensors measured physiological rod loading autonomously over the observation period and delivered the data daily to bonded smartphones. At euthanasia the relative rod load dropped to 67% of the respective maximum value for the L23 segment and to 30% for the L34 segment. In agreement, the total range of motion of both operated segments was lower compared to an intact reference segment (L23: 0.57°; L34: 0.49°; intact L45: 4.17°). Radiologic assessment revealed fusion mass in the facet joint gaps and bilateral bridging bone around the joints at both operated segments. Conclusions: Observations of this single-case study confirm the basic ability of continuous rod load measurement to resolve the spinal fusion process as indicated by a declining rod load with progressing bone fusion. A strong clinical potential of such technology is eminent, but further data must be collected for final proof of principle.
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spelling pubmed-93190512022-07-27 Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep Windolf, Markus Heumann, Maximilian Varjas, Viktor Constant, Caroline Ernst, Manuela Richards, Robert Geoff Wilke, Hans-Joachim Benneker, Lorin Michael Medicina (Kaunas) Article Background and Objectives: Spinal fusion is an effective and widely accepted intervention. However, complications such as non-unions and hardware failures are frequently observed. Radiologic imaging and physical examination are still the gold standards in the assessment of spinal fusion, despite multiple limitations including radiation exposure and subjective image interpretation. Furthermore, current diagnostic methods only allow fusion assessment at certain time points and require the patient’s presence at the hospital or medical practice. A recently introduced implantable sensor system for continuous and wireless implant load monitoring in trauma applications carries the potential to overcome these drawbacks, but transferability of the principle to the spine has not been demonstrated yet. Materials and Methods: The existing trauma sensor was modified for attachment to a standard pedicle-screw-rod system. Two lumbar segments (L2 to L4) of one Swiss white alpine sheep were asymmetrically instrumented. After facetectomy, three sensors were attached to the rods between each screw pair and activated for measurement. The sheep was euthanized 16 weeks postoperatively. After radiological assessment the spine was explanted and loaded in flexion-extension to determine the range of motion of the spinal segments. Sensor data were compared with mechanical test results and radiologic findings. Results: The sensors measured physiological rod loading autonomously over the observation period and delivered the data daily to bonded smartphones. At euthanasia the relative rod load dropped to 67% of the respective maximum value for the L23 segment and to 30% for the L34 segment. In agreement, the total range of motion of both operated segments was lower compared to an intact reference segment (L23: 0.57°; L34: 0.49°; intact L45: 4.17°). Radiologic assessment revealed fusion mass in the facet joint gaps and bilateral bridging bone around the joints at both operated segments. Conclusions: Observations of this single-case study confirm the basic ability of continuous rod load measurement to resolve the spinal fusion process as indicated by a declining rod load with progressing bone fusion. A strong clinical potential of such technology is eminent, but further data must be collected for final proof of principle. MDPI 2022-07-06 /pmc/articles/PMC9319051/ /pubmed/35888618 http://dx.doi.org/10.3390/medicina58070899 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Windolf, Markus
Heumann, Maximilian
Varjas, Viktor
Constant, Caroline
Ernst, Manuela
Richards, Robert Geoff
Wilke, Hans-Joachim
Benneker, Lorin Michael
Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title_full Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title_fullStr Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title_full_unstemmed Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title_short Continuous Rod Load Monitoring to Assess Spinal Fusion Status–Pilot In Vivo Data in Sheep
title_sort continuous rod load monitoring to assess spinal fusion status–pilot in vivo data in sheep
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9319051/
https://www.ncbi.nlm.nih.gov/pubmed/35888618
http://dx.doi.org/10.3390/medicina58070899
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