Résumé
La plaque cervicale verrouillée destinée aux ostéosynthèses du rachis cervical infériur a encore récemment fait l'objet d'une approbation clinique croissante, mais jusqu'à ce jour il n'y a pas eu de travaux rapportant les propriétés biomécaniques de cet implant en laboratoire. Afin de déterminer ces propriétés, 5 rachis cervicaux humains provenant de cadavres frais ont été soumis à des tests de flexion et de torsion physiologiques, menes en trois étapes: étape 1: rachis intact, étape 2: rachis déstabilisé, étape 3: rachis préalablement déstabilisé instrumenté par une plaque cervicale verrouillée (CSLP). Les spécimens de l'étape 3 ont été également soumis à des mouvements de grande amplitude angulaire afin d'évaluer la solidité de la fixation. En flexion, le déplacement moyen des processus épineux a été de 1,21 mm à l'étape 1, de 3,19 mm à l'étape 2 et de 1,37 mm à l'étape 3. La rigidité moyenne à la torsion a été de 2,86 Nm/degré à la première étape, de 1,82 Nm/degré à la deuxième et de 2,20 Nm/degré à la troisième. A l'étape 3, les grands déplacements angulaires ont abouti à un déplacement de vis chez deux spécimens; il n'y a cependant pas eu de démontage de plaque. Sur les modèles gravement déstabilisés, la plaque CSLP a restauré la stabilité à la flexion mais pas celle à la rotation. Ceci suggère la nécessité d'un moyen d'immobilisation ou de fixation supplémentaire pour rétablir la stabilité à la rotation pendant la phase de consolidation osseuse.
Summary
The AO cervical spine locking plate (CSLP) for anterior subaxial fixation was recently received increasing clinical acclaim, yet to date the in vitro mechanical properties of this implant have not been reported. To determine the in vitro biomechanical properties of this device, five fresh human cadaver cervical spines were subjected to nondestructive testing in flexion and torsion in three stages: stage 1: intact spine; stage 2: destabilized spine; stage 3: destabilized spine with CSLP. Stage 3 specimens were also subjected to large angular displacement testing to assess the integrity of the fixation. In flexion, mean spinous process displacement was 1.21 mm for stage 1, 3.19 mm for stage 2, and 1.37 mm, for stage 3. Mean torsional stiffness was 2.86 Nm/degree in stage 1, 1.82 Nm/degree in stage 2, and 2.20 Nm/degree in stage 3. Large angular displacement testing in stage 3 resulted in screw loosening from the bone in two specimens; no screw plate loosening occurred. In our severely destabilized in vitro model, the CSLP restored flexion stability but not rotational stability. This suggests that supplemented bracing or fixation may be required to restore torsional stability.
References
Aebi M, Mohler J, Zäch GA, Morscher E (1986) Indication, surgical technique and results of 100 surgically treated fractures and fracture-dislocations of the cervical spine. Clin Orthop 203:244–257
Aebi M, Zuber K, Marchesi D (1991) Treatment of cervical spine injuries with anterior plating. Spine 16:39–45
Allen BL, Ferguson RL, Lehmann Th R, O'Brian RP (1987) A mechanistic classification of closed indirect fracture dislocations of the lower cervical spine. Spine 7:1–27
Bailey RW, Badgeley CE (1960) Stabilization of the cervical spine by anterior fusion. J Bone Joint Surg 41-A:565–594
Böhler J, Gaudernak T (1980) Anterior plate stabilization for fracture-dislocations of the lower cervical spine. J Trauma 20: 203–205
Bohlmann HH (1979) Acute fractures and dislocations of the cervical spine: an analysis of three hundred hospitalized patients and review of the literature. J Bone Joint Surg 61-A: 1119–1142
Cabanela ME, Ebersold MJ (1988) Anterior plate stabilization for bursting tear drop fractures of the cervical spine. Spine 13: 888–891
Caspar W (1982) Advances in cervical spine surgery: first experiences with the trapezoidal osteosynthetic plate and a new surgical instrumentation for anterior interbody stabilization. Orthop News 4:7–8
Cloward RB (1961) Treatment of acute fractures and fracture-dislocations of the cervical spine by vertebral body fusion. J Neurosurg 18:201–209
Coe JD, Warden KE, Sutterlin CE, McAfee PC (1989) Biomechanical evaluation of cervical spinal stabilization methods in a human cadaveric model. Spine 14:1122–1131
Goel VK, Clark CR, Harris KG, Schulte KR (1988) Kinematics of the cervical spine: effects of multiple total laminectomy and facet wiring. J Orthop Res 6:611–619
Jonsson H Jr, Cesarini K, Petren-Mallmin M, Rauschning W (1991) Locking screw-plate fixation of cervical spine fractures with and without ancillary posterior plating. Arch Orthop Trauma Surg 111:1–12
Lindsey RW, Newhouse KE, Clark CR, Lieponas JV, Murphy MJ (1990) Esophageal perforation after anterior cervical spine surgery, Presented at the Federation of Spine Association, Sect 1 CSRS, New Orleans
Morscher E, Sutter F, Jenny H, Olerud S (1986) Die vordere Verplattung der Halswirbelsäule mit dem Hohlschrauben-Plattensystem aus Titanium. Chirurg 57:702–707
Orozco Delclos R, Llovet Tapies J (1970) Osteosintesis en las fractures de raquis cervical. Rev Ortop Traumatol 14:285–288
Ripa DR, Kowall MG, Meyer PR, Rusin JJ (1991) Series of ninety-two traumatic cervical spine injuries stabilized with anterior ASIF plate fusion technique. Spine 16:46–55
Schulte K, Clark CR, Goel VK (1989) Kinematics of the cervical spine following discectomy and stabiliaztion. Spine 14: 1116–1121
Suh PB, Kostuik JP, Essens St I (1990) Anterior cervical plate fixation with the titanium hollow serew plate system. A preliminary report. Spine 15:1079–1081
Ulrich C, Wörsdörfer O, Claes L, Magerl F (1987) Comparative study of the stability of anterior and posterior cervical spine fixation procedures. Arch Orthop Trauma Surg 106:226–231
Ulrich C, et al. (1991) Biomechanis of fixation systems to the cervical spine. Spine 16:4–9
White III AA, Panjabi MM (1978) Clinical biomechanical of the spine. Lippincott, Philadelphia, pp 211–235
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Smith, S.A., Lindsey, R.W., Doherty, B.J. et al. Cervical spine locking plate: in vitro biomechanical testing. Eur Spine J 1, 222–225 (1993). https://doi.org/10.1007/BF00298363
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DOI: https://doi.org/10.1007/BF00298363