title: A biomechanical rationale for C1-ring osteosynthesis as treatment for displaced Jefferson burst fractures with incompetency of the transverse atlantal ligament.
abstract: Nonsurgical treatment of Jefferson burst fractures (JBF) confers increased rates of C1-2 malunion with potential for cranial settling and neurologic sequels. Hence, fusion C1-2 was recognized as the superior treatment for displaced JBF, but sacrifies C1-2 motion. Ruf et al. introduced the C1-ring osteosynthesis (C1-RO). First results were favorable, but C1-RO was not without criticism due to the lack of clinical and biomechanical data serving evidence that C1-RO is safe in displaced JBF with proven rupture of the transverse atlantal ligament (TAL). Therefore, our objectives were to perform a biomechanical analysis of C1-RO for the treatment of displaced Jefferson burst fractures (JBF) with incompetency of the TAL. Five specimens C0-2 were subjected to loading with posteroanterior force transmission in an electromechanical testing machine (ETM). With the TAL left intact, loads were applied posteriorly via the C1-RO ramping from 10 to 100 N. Atlantoaxial subluxation was measured radiographically in terms of the anterior antlantodental interval (AADI) with an image intensifier placed surrounding the ETM. Load-displacement data were also recorded by the ETM. After testing the TAL-intact state, the atlas was osteotomized yielding for a JBF, the TAL and left lateral joint capsule were cut and the C1-RO was accomplished. The C1-RO was subjected to cyclic loading, ramping from 20 to 100 N to simulate post-surgery in vivo loading. Afterwards incremental loading (10-100 N) was repeated with subsequent increase in loads until failure occurred. Small differences (1-1.5 mm) existed between the radiographic AADI under incremental loading (10-100 N) with the TAL-intact as compared to the TAL-disrupted state. Significant differences existed for the beginning of loading (10 N, P = 0.02). Under physiological loads, the increase in the AADI within the incremental steps (10-100 N) was not significantly different between TAL-disrupted and TAL-intact state. Analysis of failure load (FL) testing showed no significant differences among the radiologically assessed displacement data (AADI) and that of the ETM (P = 0.5). FL was Ø297.5 +/- 108.5 N (range 158.8-449.0 N). The related displacement assessed by the ETM was Ø5.8 +/- 2.8 mm (range 2.3-7.9). All specimens succeeded a FL >150 N, four of them >250 N and three of them >300 N. In the TAL-disrupted state loads up to 100 N were transferred to C1, but the radiographic AADI did not exceed 5 mm in any specimen. In conclusion, reconstruction after displaced JBF with TAL and one capsule disrupted using a C1-RO involves imparting an axial tensile force to lift C0 into proper alignment to the C1-2 complex. Simultaneous compressive forces on the C1-lateral masses and occipital condyles allow for the recreation of the functional C0-2 ligamentous tension band and height. We demonstrated that under physiological loads, the C1-RO restores sufficient stability at C1-2 preventing significant translation. C1-RO might be a valid alternative for the treatment of displaced JBF in comparison to fusion of C1-2.
authors.affiliation: Department for Traumatology and Sport Injuries, Paracelsus Medical University Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria. heiko.koller@t-online.de
authors.forename: Heiko
authors.initials: H
authors.lastname: Koller
authors.forename: Herbert
authors.initials: H
authors.lastname: Resch
authors.forename: Mark
authors.initials: M
authors.lastname: Tauber
authors.forename: Juliane
authors.initials: J
authors.lastname: Zenner
authors.forename: Peter
authors.initials: P
authors.lastname: Augat
authors.forename: Rainer
authors.initials: R
authors.lastname: Penzkofer
authors.forename: Frank
authors.initials: F
authors.lastname: Acosta
authors.forename: Klaus
authors.initials: K
authors.lastname: Kolb
authors.forename: Anton
authors.initials: A
authors.lastname: Kathrein
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hitzl
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001269:Atlanto-Occipital Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008023:Ligaments, Articular / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011859:Radiography; D016059:Range of Motion, Articular; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016474:Weight-Bearing
references.citation: Eur Spine J. 2006 Sep;15(9):1326-38
references.pmid: 16604355
references.citation: J Bone Joint Surg Am. 2004 Nov;86(11):2514-8
references.pmid: 15523027
references.citation: Acta Neurochir (Wien). 1994;129(1-2):47-53
references.pmid: 7998495
references.citation: Zhonghua Yi Xue Za Zhi. 2006 Jul 4;86(25):1743-7
references.pmid: 17054838
references.citation: J Biomech. 2001 Jan;34(1):13-21
references.pmid: 11425074
references.citation: Spine (Phila Pa 1976). 2000 Jul 1;25(13):1607-16
references.pmid: 10870135
references.citation: Spine (Phila Pa 1976). 2006 Mar 1;31(5):603-9
references.pmid: 16508560
references.citation: J Bone Joint Surg Am. 1974 Dec;56(8):1683-91
references.pmid: 4434037
references.citation: J Spinal Disord. 1995 Jun;8(3):233-6
references.pmid: 7670216
references.citation: J Neurosurg. 1991 Aug;75(2):221-7
references.pmid: 2072158
references.citation: Spine (Phila Pa 1976). 2009 Jun 1;34(13):1395-8
references.pmid: 19478659
references.citation: J Bone Joint Surg Am. 1977 Apr;59(3):332-9
references.pmid: 849944
references.citation: Acta Chir Orthop Traumatol Cech. 2003;70(5):274-8
references.pmid: 14669588
references.citation: J Bone Joint Surg Am. 1991 Jun;73(5):680-91
references.pmid: 2045393
references.citation: J Neurosurg. 1999 Oct;91(2 Suppl):139-43
references.pmid: 10505495
references.citation: Spine (Phila Pa 1976). 2008 Sep 1;33(19):2066-73
references.pmid: 18758362
references.citation: Spine (Phila Pa 1976). 2007 Mar 1;32(5):593-600
references.pmid: 17334296
references.citation: Spine J. 2008 Sep-Oct;8(5):821-6
references.pmid: 17981098
references.citation: Eur Spine J. 2007 Apr;16(4):479-84
references.pmid: 17051397
references.citation: J Biomech. 2002 Jun;35(6):725-32
references.pmid: 12020991
references.citation: Eur Spine J. 1998;7(2):148-54
references.pmid: 9629939
references.citation: Orthopade. 1999 Aug;28(8):651-661
references.pmid: 28246986
references.citation: Neurosurgery. 2007 Jan;60(1 Supp1 1):S103-11
references.pmid: 17204870
references.citation: Spine (Phila Pa 1976). 2008 Aug 15;33(18):E659-62
references.pmid: 18708920
references.citation: Spine (Phila Pa 1976). 1995 Dec 1;20(23):2493-8
references.pmid: 8610243
references.citation: Eur Spine J. 2000 Oct;9(5):430-3
references.pmid: 11057538
references.citation: J Orthop Res. 1988;6(3):452-61
references.pmid: 3357093
references.citation: J Neurosurg Spine. 2007 Aug;7(2):117-23
references.pmid: 17688049
references.citation: Spine (Phila Pa 1976). 2008 Oct 1;33(21):2278-83
references.pmid: 18784629
references.citation: J Pediatr Orthop. 2007 Jan-Feb;27(1):23-6
references.pmid: 17195792
references.citation: Spine (Phila Pa 1976). 1998 Sep 15;23(18):1963-7
references.pmid: 9779528
references.citation: Acta Neurochir (Wien). 2002 Nov;144(11):1187-92
references.pmid: 12434175
references.citation: Eur Spine J. 2009 Aug;18(8):1135-53
references.pmid: 19224254
references.citation: J Bone Joint Surg Am. 2004 Mar;86(3):561-8
references.pmid: 14996883
references.citation: J Neurosurg. 1997 Jul;87(1):96-9
references.pmid: 9202272
references.citation: Eur Spine J. 2009 Jul;18(7):978-91
references.pmid: 19225813
references.citation: Spine (Phila Pa 1976). 2006 Mar 15;31(6):632-8
references.pmid: 16540865
references.citation: Unfallchirurg. 2006 Dec;109(12):1099-103
references.pmid: 16969653
references.citation: Spine (Phila Pa 1976). 2004 Apr 1;29(7):823-7
references.pmid: 15087806
references.citation: Clin Orthop Relat Res. 1999 Sep;(366):98-106
references.pmid: 10627723
references.citation: Spine (Phila Pa 1976). 1988 May;13(5):450-2
references.pmid: 3187689
references.citation: Unfallchirurg. 2006 Sep;109(9):754-60
references.pmid: 16874483
references.citation: J Neurosurg Spine. 2005 Apr;2(4):411-7
references.pmid: 15871479
references.citation: Spine (Phila Pa 1976). 2009 Feb 15;34(4):371-7
references.pmid: 19214096
references.citation: J Neurosurg Spine. 2005 Jan;2(1):83-7
references.pmid: 15658133
references.citation: J Bone Joint Surg Am. 1970 Apr;52(3):543-9
references.pmid: 5425648
references.citation: Neurosurgery. 2008 Jul;63(1 Suppl 1):ONSE100-1; discussion ONSE101
references.pmid: 18728610
references.citation: J Neurosurg Spine. 2009 May;10(5):466-73
references.pmid: 19442009
references.citation: Acta Orthop Scand Suppl. 1957;23:1-150
references.pmid: 13434893
references.citation: Neurosurgery. 1996 Jan;38(1):44-50
references.pmid: 8747950
references.citation: Spine (Phila Pa 1976). 2001 Nov 15;26(22):2467-71
references.pmid: 11707712
references.citation: Neurosurgery. 2007 Sep;61(3 Suppl):87-93; discussion 93
references.pmid: 17876237
references.citation: J Spinal Disord Tech. 2005 Oct;18(5):402-5
references.pmid: 16189450
references.citation: Eur Spine J. 1999;8(3):241-3
references.pmid: 10413353
references.citation: J Spinal Disord. 1993 Apr;6(2):162-5
references.pmid: 8504229
references.citation: Spine (Phila Pa 1976). 1988 Jul;13(7):726-30
references.pmid: 3194778
references.citation: Spine (Phila Pa 1976). 2002 Nov 15;27(22):2435-40
references.pmid: 12435971
references.citation: Spine (Phila Pa 1976). 2008 Jul 15;33(16):1744-9
references.pmid: 18628707
references.citation: Spine (Phila Pa 1976). 2009 Mar 1;34(5):484-90
references.pmid: 19247169
references.citation: AJNR Am J Neuroradiol. 2007 Oct;28(9):1819-23
references.pmid: 17893223