Our reference: OTSR 928 P-authorquery-v9

AUTHOR QUERY FORM

Journal: OTSR Please e-mail or fax your responses and any corrections to:

E-mail: corrections.esme@elsevier.thomsondigital.com

Article Number: 928 Fax: +33 (0) 1 71 16 51 88

Dear Author,

Please check your proof carefully and mark all corrections at the appropriate place in the proof (e.g., by using on-screenannotation in the PDF file) or compile them in a separate list. Note: if you opt to annotate the file with software other thanAdobe Reader then please also highlight the appropriate place in the PDF file. To ensure fast publication of your paper pleasereturn your corrections within 48 hours.

For correction or revision of any artwork, please consult http://www.elsevier.com/artworkinstructions.

Any queries or remarks that have arisen during the processing of your manuscript are listed below and highlighted by flags inthe proof. Click on the ‘Q’ link to go to the location in the proof.

Location in Query / Remark: click on the Q link to goarticle Please insert your reply or correction at the corresponding line in the proof

Q1 Please confirm that given names and surnames have been identified correctly.

Please check this box or indicate your approval ifyou have no corrections to make to the PDF file

Thank you for your assistance.

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx

Available online at

ScienceDirectwww.sciencedirect.com

Original article

C1-C2 stabilization by harms arthrodesis: Indications, technique,complications and outcomes in a prospective 26-case series

P. Bourdillona,∗, G. Perrina, F. Lucasa, R. Debargea, C. Barreya,bQ1

a Service de Neurochirurgie C et Chirurgie du Rachis, Hôpital Pierre-Wertheimer, GHE, Hospices Civils de Lyon, Université Claude-Bernard Lyon 1, 59,boulevard Pinel, 69500 Bron, Franceb Laboratoire de Biomécanique, Art et Métiers Paristech, ESNAM, 151, boulevard de l’Hôpital, 75013 Paris, France

a r t i c l e i n f o

Article history:Accepted 27 September 2013

Keywords:HarmsC1-C2 fusionCervical fusionC1-C2 instabilityC1-C2 screwsCervical spine arthrodesis

a b s t r a c t

C1-C2 arthrodesis is a surgical challenge due to the proximity of neurovascular structures (vertebralarteries and spinal cord) and the wide range of motion of the joint, hampering bone fusion. A variety oftechniques have been successively recommended to reduce anatomic risk and improve results in termsof biomechanical stability and fusion rates. Recently, Harms described a new technique using polyaxialscrews in the C1 lateral masses and C2 pedicles. The present study reports our experience in a consecutiveseries of 26 patients operated on by C1-C2 arthrodesis using the Goel and Harms technique, and detailstechnical aspects step by step. Routine systematic immediate postoperative CT and 6-month CT controlledscrew positioning and assessed fusion. Follow-up was at least 1 year, except in 2 cases (10 months).Twenty-six patients with a mean age of 57 years were included. Indications comprised: C2 non-union(n = 11), C1-C2 fracture and/or dislocation (n = 11), inflammatory pathology (n = 2) and tumoral pathology(n = 2). The results showed the technique to be reliable (no neurovascular complications and 85% of screwswith perfect positioning) and an excellent rate of fusion (100% at 6 months). Anatomic and biomechanicalconsiderations, combined with the present clinical and radiological outcomes, indicate that Goel andHarms fusion is to be considered the first-line attitude of choice for posterior C1-C2 arthrodesis.Level of Evidence: Level IV prospective study.

© 2014 Published by Elsevier Masson SAS.

1. Introduction

C1-C2 instability may have various causes, usually involving theC1-C2 axis or disc and ligamentary structure. Etiology is predomi-nantly acute trauma, odontoid non-union, inflammatory pathology(rheumatoid arthritis) or tumor [1,2].

Atlanto-axial arthrodesis is technically demanding due to theanatomic relations and wide range of motion of the joint, hin-dering good-quality bone fusion [3]. Surgical C1-C2 fusion wasfirst described by W. Gallie in 1939, and consisted in posteriorwiring [4], as subsequently developed by Brooks in the 1970s [5].Biomechanical efficacy, however, was limited and wiring servedmore to maintain the interlaminar graft in position than to achievereal three-dimensional stability: a rigid cervical collar with 5 sup-ports and a frontal band was associated for a minimum 3 months.Later, interlaminar hooks, with better biomechanical propertiesthan wiring, were introduced [6].

Transarticular atlanto-axial screw fixation, introduced byMagerl in 1986 [7], provided very high quality biomechanical

∗ Corresponding author.E-mail address: pierre.bourdillon@neurochirurgie.fr (P. Bourdillon).

stability, with spectacularly improved fusion rates as comparedto the earlier posterior wiring techniques [8–12]. There were,however, several drawbacks, notably including the difficulty of per-formance in case of atlanto-axial dislocation or subluxation withloss of C1-C2 alignment.

In 2001, Harms developed Goel’s work on atlanto-axial screwfixation, describing a stabilization technique based on fixation ofthe C1 lateral masses and C2 isthmus using polyaxial screws [13].Biomechanical results are comparable to those with Magerl’s tech-nique [14,15] and surgery remains possible in case of posterior arcinvolvement (unlike with hook fixation) or loss of C1-C2 alignment(unlike with Magerl’s procedure).

The present report is of an original consecutive prospectiveseries of 26 patients managed by cervical or occipito-cervicalarthrodesis including C1-C2, using the Harms technique.

2. Materials and methods

Patients aged over 18 years were consecutively included fromJanuary 1st, 2009 to January 1st, 2012. Minimum follow-up was 1year in all but 2 cases, in which it was for 10 months.

In all patients, posterior cervical arthrodesis including C1-C2was indicated consensually by the center’s spinal surgery team.

1877-0568/$ – see front matter © 2014 Published by Elsevier Masson SAS.http://dx.doi.org/10.1016/j.otsr.2013.09.019

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

2 P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx

Inclusion was independent of etiology.The following clinical data were analyzed: age, gender, etiol-

ogy of instability, operative time, blood loss, pre- and postoperativeneurological status, and complications (neurological, infectious andgeneral).

The following CT data were analyzed: cortical fracture(> 2 mm) on immediate postoperative imaging, and rate offusion on 6-month postoperative CT. Mechanical complications(displacement, rupture of osteosynthesis material, screw detach-ment, etc.) were collected from the two postoperative CTscans.

C1-C2 fusion used polyaxial screws with a diameter of 3.5 mmin C2 and 4 mm in C1, connected up by 3.2-mm titaniumrods (VERTEX, Medtronic®, Minneapolis, MIN, USA), on eitherside independently. All patients were operated on by the samesurgeon (CB), to reduce variability related to surgical tech-nique.

2.1. Surgical technique

Patients were positioned prone, with a Mayfield® skull clamp,with the head held in neutral position or slight flexion so as tofacilitate C1-C2 exposure.

A classic medial posterior cervical approach was performed,exposing the spine from C0 to C3. Exposure had to be sufficientlylateral for the whole of C2 and also the vertebral artery groove on

the posterior arc of C1 to be visible. Particular care was taken indissecting the posterior arc of C1 to avoid vertebral artery lesion(non-traumatic subperiosteal dissection).

The entry point for the C2 isthmus screw was at the junctionof the superomedial and superolateral quadrants of the isthmus,slightly outside of the junction between the lamina and the facet(Fig. 1). The screw-hole was created using a 2.7 mm bit heldabout 30◦ upward and 20◦ convergent. Lateral fluoroscopic con-trol allowed sagittal orientation to be adjusted. The diameter of thepolyaxial Medtronic® VERTEX C2 isthmus screw (Fig. 2) was usu-ally 3.5 mm, with length ranging between 18 and 30 mm dependingon the patient’s anatomy (whence the importance of pre-operativeplanning, with precise measurement of the direction and diameterof the C2 isthmus).

The C2 root was systematically spared, being distracted down-ward using an Olivecrona spatula, taking care to limit (usually byswabbing) bleeding of the venous plexuses that are very numerousin this region.

The entry point for the C1 lateral mass lies at the intersection of asagittal axis through the middle of the C1-C2 joint and a transverseaxis through the junction of the posterior arc and the C1 lateral mass(Fig. 3). Depending on its morphology, the posterior arc of C1 maybe partially rasped to facilitate screw placement. The screw-holeis created using a 3 mm bit, with a slightly upward (20◦) and con-vergent (10◦) direction. Lateral fluoroscopic control allows sagittaladjustment. Screw diameters were 4 mm, with length usually of 28

Fig. 1. Screw entry points in C1 (left) and C2 (right).

Fig. 2. Positioning of isthmus screws in C2. The medial edge of the pedicle is located and palpated with a spatula within the canal in contact with the medial side of thepedicle.

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx 3

Fig. 3. Screw positioning in the left C1 lateral mass. Entry point exposure requires downward retraction of the venous plexuses and C2 root. The medial and lateral edges ofthe C1 body is palpated by spatula.

Fig. 4. C1-C2 assembly following Harms (3D CT).

to 32 mm, depending on patient anatomy. Like for C2, the polyaxialMedtronic® VERTEX screw was used (Fig. 4).

After screw positioning, radiological control was repeated and 2Medtronic® VERTEX rods were fitted to connect the pairs of screwson either side (Figs. 4 and 5).

After radiological control, the posterior arcs were freshenedunder abundant irrigation using a large-diameter (4 or 5 mm) burr.A large interlaminar graft was performed using decortication bone

Fig. 5. Posterior arch freshening and interlaminar grafting.

harvested during surgery associated to hydroxyapatite granules(Fig. 5).

3. Results

Mean age was 57 years (SD, 19.3 years), with 16 male and 10female patients (Table 1).

Eleven of the 26 patients (Fig. 6) presented odontoid fracturenon-union, 2 inflammatory pathologies (1 pannus on rheumatoidarthritis, 1 gout), 11 trauma (fracture or severe C1-C2 sprain) and2 tumors (1 chordoma, 1 odontoid metastasis).

Mean operative time was 160 minutes (SD, 53 min; range,1 h 15min–4 h 50 min) and mean blood loss 260 mL (SD, 203 mL;range, 90–890 mL), taking all assemblies together. For 1-step Harms

Fig. 6. Indications.

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

4 P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx

Table 1Summary of indications, pre- and postoperative neurological status and operative data.

Age Gender Indication Preoperativeneurologicalstatus

Type of assembly Associateddecompression

Postoperativeneurologicalstatus

Operativetime

Blood loss

Patient 1 81 M Non-union of odontoidfracture (4mm), facingodontoid granuloma(type 2)

Frankel C Harms C1-C2 C1laminectomy

Frankel D 2 h 15 15 mL

Patient 2 59 M Complex C2 fracture,severe C1-C2 sprain

Frankel E Harms C1-C2 (left) andtransarticular (right).Posterior graft, odontoidscrew fixation

No Frankel E 3 h 50 50 mL

Patient 3 18 M Non-union of odontoidfracture (OBAR type 2)

Frankel E Harms C1-C2, odontoidscrew fixation

No Frankel E 3 h 50 400 mL

Patient 4 73 F Fracture of both C2lateral masses

Frankel E Harms C1-C3, anteriorarthrodesis, posterior graft

No Frankel E 1 h 15 120 mL

Patient 5 84 M Odontoid non-union(OBAR, type 2),retro-odontoid pannus

Frankel E Harms C1-C2, interlaminargraft

No Frankel E 1 h 30 250 mL

Patient 6 71 F Non-union of odontoidbase fracture +granuloma

Frankel E Harms C1-C2, interlaminargraft

No Frankel E 2 h 15 890 mL

Patient 7 25 M Fracture of C1 lateralmasses (congenitalC0-C1 fusion)

Frankel E Harms C0-C1-C2,interlaminar graft

No Frankel E 2 h 45 410 mL

Patient 8 51 M C0-C1 dislocation Frankel A Harms C0-C1-C2,interlaminar graft

No Frankel D 2 h 15 50 mL

Patient 9 77 F Non-union of odontoidfracture (horizontal)

Frankel E Harms C1-C2, interlaminargraft

No Frankel E 1 h 30 160 mL

Patient 10 70 M Fracture of odontoidbase with 11 mmposterior displacement

Frankel E Harms C1-C2, interlaminargraft, odontoid screwfixation

No Frankel E 3 h 15 140 mL

Patient 11 33 M Bi-articular C2 fracture,C2-C3 subluxation

Frankel E Harms C1-C3, interlaminargraft

No Frankel E 1 h 30 90 mL

Patient 12 60 F C1-C2 dislocation,neurologic assessmentimpossible

Non-assessable(coma)

Harms C1-C2, interlaminargraft

No Non-assessable(coma)

1 h 45 250 mL

Patient 13 74 M Non-union of odontoidfracture + pannus

Frankel C Harms C1-C2 Laminectomy Frankel D 2 h 15 210 mL

Patient 14 27 M Traumatic C1-C2subluxation

Frankel D Harms C1-C2, interlaminargraft

No Frankel E 2 h 00 240 mL

Patient 15 65 F Pathologic fracture(complete C2 bodylysis)

Frankel E C1 to C5 with C2 isthmusscrew fixation, C2 and C4cementoplasty

No Frankel E 4 h 50 300 mL

Patient 16 58 F Intracanal clivuschordoma

Frankel E Harms C0-C4 (NB: right C1and left C2 not screwed)

No Frankel E 2 h 50 320 mL

Patient 17 20 M Non-union of odontoidfracture (OBAR onRoy-Camilleclassification)

Frankel E Harms C1-C2 No Frankel E 2 h 30 250 mL

Patient 18 58 F C2-C3 dislocationfracture

Frankel E Harms C1-C3, C2-C3 cageplate

No Frankel E 3 h 30 170 mL

Patient 19 36 F C1-C2 instability onrheumatoid arthritis

Frankel E Harms C1-C2, interlaminargraft

No Frankel E 2 h 15 150 mL

Patient 20 60 M C1-C2 tophus (on gout)and odontoid fracture

Frankel E Harms C1-C2 No Frankel E 2 h 45 220 mL

Patient 21 58 F Fracture non-union(OBAR, type 2)

Frankel E Harms C1-C2, odontoidscrew fixation

No Frankel E 3 h 30 100 mL

Patient 22 82 M Fracture non-union(OBAR, type 2)

Frankel E Harms C1-C2, odontoidscrew fixation

No Frankel E 4 h 00 850 mL

Patient 23 64 M C2 Fracture non-union(hook detachment)

Frankel D +posteriorcordonalsyndrome

Harms C1-C2, interlaminargraft

No Frankel E +resolution ofposteriorcordonalsyndrome

3 h 00 150 mL

Patient 24 66 M Complex C2 fracture,severe C1-C2 sprain

Frankel A Harms C1-C3, interlaminargraft

No Frankel A 2 h 30 400 mL

Patient 25 63 M Bipedicular C2 fracture Frankel E Harms C1-C3, interlaminargraft

No Frankel E 2 h 00 320 mL

Patient 26 57 M Anderson III C2 fracture Frankel E Harms C1-C3, odontoidscrew fixation,interlaminar graft

No Frankel E 4 h 00 150 mL

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx 5

Fig. 7. Pre- and postoperative neurologic status.

posterior C1-C2 assemblies, the mean figures were 130 min and240 mL.

There was no postoperative neurological aggravation. Five ofthe 7 neurologically impaired patients showed clinical neurologi-cal improvement (Fig. 7): 3 with non-union of an Anderson type-IIfracture, and 2 with traumatic C1-C2 dislocation.

Immediate postoperative radiological control, performedwithin 2 days of surgery, comprised thin-slice CT centered on C1-C2, with sagittal and coronal multiplanar reconstruction (Fig. 8).In 2 cases, the scanner was not available in the intensive caresetting, and AP and lateral upper cervical spine X-rays were takeninstead.

All screws were correctly positioned, with no cortical damagein most cases (22 out of 26: 85%). In the other 4 cases, the cor-tical fracture was less than 2 mm, without clinical impact; therewere no fractures longer than 2 mm. Three of the 4 fractureswere of the C0-C1 joint line, and the fourth of the transversecanal at C2 (without vascular impact) (Figs. 9 and 10). Norevision operations were required and there were no clinicalor radiological consequences (notably vascular or neurologi-cal).

Patients were followed up at 6 months and 1 year. SystematicCT control at 6 months (Fig. 11) found no non-union or displace-ment of material. C1-C2 bone bridges were systematic, although ofvariable quality. Grafts were of poorer quality in case of C1 and/orC2 laminectomy, with smaller bone bridges.

Fig. 9. Postoperative CT, assessing screw positioning.

4. Discussion

The present results are strictly in line with the literature[13,16,17]: an excellent rate of fusion, and very good reproducibil-ity of correct screw positioning, testifying to the reliability of thetechnique.

The fact that there were no cases of non-union or mechan-ical complications in the present series confirms the interest ofthis technique for achieving high-quality fusion. The early pos-terior wiring techniques of C1-C2 arthrodesis, mentioned above,achieved fusion in only two-thirds of cases [18,19] despite 3months’ cervical collar immobilization; the collars, moreover,incurred well-established specific morbidity such as delayed heal-ing or operative site infection or scabbing (especially in elderlysubjects, who frequently show denutrition) and non-negligiblepsychological impact. Following Harms arthrodesis, we recom-mend temporary (6 weeks) use of a supple collar when (and onlywhen) the cervical spine resumes load-bearing.

As in Harms’ own series of 37 patients [13], all of the screwswere more or less well positioned, and there were no vascular orneurologic lesions. We did, however, find it wise to use short mono-cortical and isthmus screws in C2, to minimize to risk of lesion tothe vertebral artery in its groove forward of the tip of the screw.The main technical difficulty encountered concerned venous bleed-ing due to the large number of plexuses around the C2 root andfacing the entry point on the C1 lateral mass. During exposure,

Fig. 8. Postoperative CT, showing good screw positioning in a patient who received odontoid screw fixation for complex displaced C1-C2 fracture.

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

6 P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx

Fig. 10. C1-C2 dislocation fracture (left). Day-2 postoperative CT (right) shows vertebral artery canal fracture on the left side.

these plexuses should be painstakingly distracted downward, pre-ventively, using 1 or 2 spatulas and hemostatic agents. In case ofpersistent bleeding, which is of venous origin, prolonged swabbingis usually effective. Also, due to the proximity of the C2 root, unpro-tected by any bony structure, bipolar forceps coagulation is to bepreferred to monopolar sectioning.

Some authors recommend C2 root ligature, to promotehemostasis; this is not, however, without clinical consequences(hypoesthesia of the gonion and retroauricular region, associatedwith risk of neuralgia), and we consider the techniques describedabove to be sufficiently effective in almost all cases. The quality ofthe interlaminar grafts, moreover, is not such as to encourage C1-C2grafting sacrificing the C2 root.

C1-C2 hooks (linked by rods or clamps) avoid the risk of verte-bral artery lesion incurred by screwing, but have the disadvantageof involving intracanal surgery (with supplementary neurologi-cal risk) and cannot be used in case of laminar involvement (e.g.,post-traumatic or secondary to laminectomy). Biomechanically,moreover, although laminar hooks provide anteroposterior sta-bility comparable to Magerl’s C1-C2 screw fixation, stability inrotation is much poorer [8]. The posterior interlaminar graft is alsolarger and more satisfactory when performed medially (betweenrods, as is the case in screwing) rather than laterally (as in hookfixation, where it is lateral to the rods linking the hooks).

Biomechanically, transarticular C1-C2 screw fixation, as initiallydescribed with Magerl’s technique, provides much better stability

in both flexion/extension and rotation than do wiring techniques[8,20,21].

Stability has been compared between the Harms and Magerltechniques [8,17,22]: the two are equivalent; the Harms tech-nique has the better biomechanical properties reported so far withposterior C1-C2 arthrodesis. Given the potential technical difficul-ties of Magerl screw fixation, especially when C1-C2 alignmentis not conserved, and the greater risk of vertebral artery lesion(due to less convergent screw positioning), the Harms techniqueappears preferable. Associating posterior wiring to the Magerl tech-nique, as suggested by several teams in case of difficulty [11,23],does not seem indicated: it involves an intracanal step, increas-ing neurologic risk for a biomechanical benefit that has not beenassessed.

Certain authors have described a minimally invasiveHarms procedure [24]. Only 5 cases have as yet beenreported, and benefit and interest remain to be eluci-dated.

Navigation techniques have recently been described, and candoubtless enhance reliability [25], especially in difficult cases,although the upper cervical spine is not the ideal site for nav-igation (limited exposure, deep operative site, mobile segment,etc.).

Taken together, the above arguments and present findings sug-gest to us that Harms fusion is the first-line reference method forposterior C1-C2 arthrodesis.

Fig. 11. Immediate postoperative (left) and 6-month (right) X-ray and CT control in a patient receiving Harms fusion with extension to C0. Excellent posterior fusion at 6months, with posterior bone graft remodelling.

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

Please cite this article in press as: Bourdillon P, et al. C1-C2 stabilization by harms arthrodesis: Indications, technique, complicationsand outcomes in a prospective 26-case series. Orthop Traumatol Surg Res (2014), http://dx.doi.org/10.1016/j.otsr.2013.09.019

ARTICLE IN PRESSG ModelOTSR 928 1–7

P. Bourdillon et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2014) xxx–xxx 7

Disclosure of interest

The authors declare that they have no conflicts of interest con-cerning this article.

References

[1] Benazet JP, Hamma A, Saillant G, Rakover JP, Roy-Camille R. Surgery ofthe upper cervical spine in rheumatoid arthritis. Indications and resultsa propos of 28 cases. Rev Chir Orthop Reparatrice Appar Mot 1996;82:681–90.

[2] Mestdagh H, Vigier P, Butruille Y, Berger M. Functional results in C1-C2arthrodesis of fractures of the odontoid process. Rev Chir Orthop ReparatriceAppar Mot 1988;74(Suppl. 2):307–10.

[3] Aryan HE, Newman CB, Nottmeier EW, Acosta Jr FL, Wang VY, Ames CP. Stabi-lization of the atlantoaxial complex via C-1 lateral mass and C-2 pedicle screwfixation in a multicenter clinical experience in 102 patients: modification ofthe Harms and Goel techniques. J Neurosurg Spine 2008;8:222–9.

[4] Gallie WE. Skeletal traction in the treatment of fractures and dislocations of thecervical spine. Ann Surg 1937;106:770–6.

[5] Brooks AL, Jenkins EB. Atlanto-axial arthrodesis by the wedge compressionmethod. J Bone Joint Surg 1978;60:279–84.

[6] Holness RO, Huestis WS, Howes WJ, Langille RA. Posterior stabilization withan interlaminar clamp in cervical injuries: technical note and review of thelong-term experience with the method. Neurosurgery 1984;14:318–22.

[7] Magerl F, Seemann P. Stable posterior fusion of the atlas and axis by transar-ticular screw fixation. In: Society C.S.R., editor. Cervical Spine. New York:Springer-Verlag; 1986. p. 322–7.

[8] Grob D, Crisco 3rd JJ, Panjabi MM, Wang P, Dvorak J. Biomechanical eval-uation of four different posterior atlantoaxial fixation techniques. Spine1992;17:480–90.

[9] Hajek PD, Lipka J, Hartline P, Saha S, Albright JA. Biomechanical study of C1-C2posterior arthrodesis techniques. Spine 1993;18:173–7.

[10] Melcher RP, Puttlitz CM, Kleinstueck FS, Lotz JC, Harms J, Bradford DS.Biomechanical testing of posterior atlantoaxial fixation techniques. Spine2002;27:2435–40.

[11] Naderi S, Crawford NR, Song GS, Sonntag VK, Dickman CA. Biomechanical com-parison of C1-C2 posterior fixations. Cable, graft, and screw combinations. Spine1998;23:1946–55.

[12] Smith MD, Phillips WA, Hensinger RN. Complications of fusion to the uppercervical spine. Spine 1991;16:702–5.

[13] Harms J, Melcher RP. Posterior C1-C2 fusion with polyaxial screw and rodfixation. Spine 2001;26:2467–71.

[14] Park J, Scheer JK, Lim TJ, Deviren V, Ames CP. Biomechanical analysis of Goeltechnique for C1-2 fusion. J Neurosurg Spine 2011;14:639–46.

[15] Lu B, He X, Zhao CG, Li HP, Wang D. Biomechanical study of artificial atlanto-odontoid joint. Spine 2009;34:1893–9.

[16] Stokes JK, Villavicencio AT, Liu PC, Bray RS, Johnson JP. Posterior atlantoaxialstabilization: new alternative to C1-2 transarticular screws. Neurosurg Focus2002;12:E6.

[17] Mummaneni PV, Lu DC, Dhall SS, Mummaneni VP, Chou D. C1 lateral massfixation: a comparison of constructs. Neurosurgery 2010;66(3 Suppl.):153–60.

[18] Coyne TJ, Fehlings MG, Wallace MC, Bernstein M, Tator CH. C1-C2 posteriorcervical fusion: long-term evaluation of results and efficacy. Neurosurgery1995;37:688–92.

[19] Farey ID, Nadkarni S, Smith N. Modified Gallie technique versus transarticularscrew fixation in C1-C2 fusion. Clin Orthop Relat Res 1999;359:126–35.

[20] Madawi AA, Casey AT, Solanki GA, Tuite G, Veres R, Crockard HA. Radiologi-cal and anatomical evaluation of the atlantoaxial transarticular screw fixationtechnique. J Neurosurg 1997;86:961–8.

[21] Stillerman CB, Wilson JA. Atlanto-axial stabilization with posterior transartic-ular screw fixation: technical description and report of 22 cases. Neurosurgery1993;32:948–54.

[22] Elliott RE, Tanweer O, Boah A, Morsi A, Ma T, Frempong-Boadu A, et al. Outcomecomparison of atlantoaxial fusion with transarticular screws and screw-rodconstructs: meta-analysis and review of literature. J Spinal Disord Tech 2012.

[23] Scholz M, Schnake K, Hoffmann R, Kandziora F. Revision strategy after failureof Magerl-Gallie fusion procedure. Der Unfallchirurg 2011;114:61–5.

[24] Holly LT, Isaacs RE, Frempong-Boadu AK. Minimally invasive atlantoaxialfusion. Neurosurgery 2010;66(3 Suppl.):193–7.

[25] Weng C, Tian W, Li ZY, Liu B, Li Q, Wang YQ, et al. Surgical management of symp-tomatic os odontoideum with posterior screw fixation performed using theMagerl and Harms techniques with intraoperative 3-dimensional fluoroscopy-based navigation. Spine 2012;37:1839–46.

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301