atlantoaxial rotatory subluxation in skeletally immature patients

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British Journal of Neurosurgery 2002; 16(2): 154–157 ISSN 0268–8697 print/ISSN 1360–046X online/02/020154–04 © The Neurosurgical Foundation DOI: 10.1080/0268869022013177 8 ORIGINAL ARTICLE Atlantoaxial rotatory subluxation in skeletally immature patients S.-C. LEE, T.-N. LUI & S.-T. LEE Department of Neurosurgery, Chang Gung University & Chang Gung Memorial Hospital, Taoyuan, Taiwan Abstract Treatments of atlanto-axial rotatory subluxation in children are generally conservative. Previous reports have proposed that surgical treatment be reserved for fixed rotatory subluxation of more than 3 months duration, irreducible deformity or cases of recurrence. Six skeletally immature patients with Fielding type III atlanto-axial rotatory subluxation were treated conservatively with or without subsequent atlanto-axial arthrodesis. The follow-up period for all the cases exceeded 18 months. Results and outcomes were analysed with an emphasis on the delay until diagnosis, causes of delays in diagnosis and factors influencing the necessity of surgical intervention. Neither mortality nor major morbidity was noted in any cases in this study. In our experience, type III fixed rotatory subluxation of 6 weeks duration will potentially recur. We recommend early surgery for type III fixed rotatory subluxation of more than than 3 months’ duration, with atlanto-axial arthrodesis being a safe and effective procedure in children. Key words: Arthrodesis, C1–C2, rotatory subluxation, Grisel’s syndrome. Introduction Atlanto-axial rotatory subluxation is typically seen in children and is often easily corrected. Most cases can be treated successfully using skeletal skull traction and maintaining the reduction with an external orthosis for 3–6 months. A delayed diagnosis is the most common cause of prolonged atlanto-axial rota- tory subluxation leading to conservative treatment failure. Previous reports have described atlanto-axial arthrodesis for fixed rotatory subluxation of more than 3 months duration or cases in which reduction was not maintained by 6 months’ use of an external orthosis. In this article, type III atlanto-axial rotatory subluxation as classified by Fielding et al. was treated with conservative treatment and/or surgery in six patients. The results of conservative and surgical treatment are described, and we attempt to deter- mine the most appropriate treatment strategy for type III atlanto-axial rotatory subluxation in children. Materials and methods Six children with C1–C2 rotatory subluxation treated between 1993 and 1998 in our hospital were retro- spectively reviewed. The patients comprised three males and three females, between 7 and 12 years of age (average 9 years), and all were symptomatic. Radiographic studies showed C1–C2 rotatory subluxation of type III according to Fielding and Hawkins’ classification. Records were reviewed for possible causation, clinical presentations, imaging studies, diagnosis, treatments and outcomes. Follow- up lasting at least 18 months was assessed by reviewing each patient’s notes, interviews, clinical examinations, anonymous questionnaires and follow- up serial cervical spine imaging. All six patients had presented with a sudden onset of persisting, painful torticollis and limited neck motion, four occurring when the patients awoke. The only past history was an episode of upper respiratory tract infection in four patients before the onset of the torticollis, and no history of significant trauma was found in any of the patients. On examination, the patients were normally developed. All had painful torticollis and limited neck motion or pain on turning the neck with no apparent motor or sensory deficits. The six patients had been seen previously by other doctors who had missed the diagnosis of the atlanto-axial rotatory subluxation. The delay in diagnosis ranged between 2 weeks and 5 months (Table I). Patients were admitted to our hospital for further evaluation and treatment once the diagnosis had been made. Correspondence: Tai-Ngar Lui, Department of Neurosurgery, Chang Gung Memorial Hospital, 5, Fu-Shing Street, 333, Kweishan, Taoyuan, Taiwan. Tel: 886–3–3281200 Ext. 2119. Fax: 886–3–3285818. Email: [email protected] Received for publication 11 May 2001. Accepted 11 February 2002. Br J Neurosurg Downloaded from informahealthcare.com by University of Maastricht on 06/19/14 For personal use only.

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Page 1: Atlantoaxial rotatory subluxation in skeletally immature patients

British Journal of Neurosurgery 2002; 16(2): 154–157

ISSN 0268–8697 print/ISSN 1360–046X online/02/020154–04 © The Neurosurgical FoundationDOI: 10.1080/0268869022013177 8

ORIGINAL ARTICLE

Atlantoaxial rotatory subluxation in skeletally immature patients

S.-C. LEE, T.-N. LUI & S.-T. LEE

Department of Neurosurgery, Chang Gung University & Chang Gung Memorial Hospital, Taoyuan, Taiwan

AbstractTreatments of atlanto-axial rotatory subluxation in children are generally conservative. Previous reports have proposed thatsurgical treatment be reserved for fixed rotatory subluxation of more than 3 months duration, irreducible deformity orcases of recurrence. Six skeletally immature patients with Fielding type III atlanto-axial rotatory subluxation were treatedconservatively with or without subsequent atlanto-axial arthrodesis. The follow-up period for all the cases exceeded18 months. Results and outcomes were analysed with an emphasis on the delay until diagnosis, causes of delays indiagnosis and factors influencing the necessity of surgical intervention. Neither mortality nor major morbidity was noted inany cases in this study. In our experience, type III fixed rotatory subluxation of 6 weeks duration will potentially recur. Werecommend early surgery for type III fixed rotatory subluxation of more than than 3 months’ duration, with atlanto-axialarthrodesis being a safe and effective procedure in children.

Key words: Arthrodesis, C1–C2, rotatory subluxation, Grisel’s syndrome.

Introduction

Atlanto-axial rotatory subluxation is typically seen inchildren and is often easily corrected. Most cases canbe treated successfully using skeletal skull tractionand maintaining the reduction with an externalorthosis for 3–6 months. A delayed diagnosis is themost common cause of prolonged atlanto-axial rota-tory subluxation leading to conservative treatmentfailure. Previous reports have described atlanto-axialarthrodesis for fixed rotatory subluxation of morethan 3 months duration or cases in which reductionwas not maintained by 6 months’ use of an externalorthosis. In this article, type III atlanto-axial rotatorysubluxation as classified by Fielding et al. was treatedwith conservative treatment and/or surgery in sixpatients. The results of conservative and surgicaltreatment are described, and we attempt to deter-mine the most appropriate treatment strategy for typeIII atlanto-axial rotatory subluxation in children.

Materials and methods

Six children with C1–C2 rotatory subluxation treatedbetween 1993 and 1998 in our hospital were retro-spectively reviewed. The patients comprised threemales and three females, between 7 and 12 years of

age (average 9 years), and all were symptomatic.Radiographic studies showed C1–C2 rotatorysubluxation of type III according to Fielding andHawkins’ classification. Records were reviewed forpossible causation, clinical presentations, imagingstudies, diagnosis, treatments and outcomes. Follow-up lasting at least 18 months was assessed byreviewing each patient’s notes, interviews, clinicalexaminations, anonymous questionnaires and follow-up serial cervical spine imaging. All six patients hadpresented with a sudden onset of persisting, painfultorticollis and limited neck motion, four occurringwhen the patients awoke. The only past history wasan episode of upper respiratory tract infection in fourpatients before the onset of the torticollis, and nohistory of significant trauma was found in any of thepatients. On examination, the patients were normallydeveloped. All had painful torticollis and limited neckmotion or pain on turning the neck with no apparentmotor or sensory deficits. The six patients had beenseen previously by other doctors who had missed thediagnosis of the atlanto-axial rotatory subluxation.The delay in diagnosis ranged between 2 weeks and5 months (Table I). Patients were admitted to ourhospital for further evaluation and treatment once thediagnosis had been made.

Correspondence: Tai-Ngar Lui, Department of Neurosurgery, Chang Gung Memorial Hospital, 5, Fu-Shing Street, 333, Kweishan,Taoyuan, Taiwan. Tel: 886–3–3281200 Ext. 2119. Fax: 886–3–3285818. Email: [email protected]

Received for publication 11 May 2001. Accepted 11 February 2002.

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Page 2: Atlantoaxial rotatory subluxation in skeletally immature patients

Atlantoaxial rotatory subluxation 155

The findings of imaging studies were similar forall six cases, with the anteroposterior open-mouthradiograph showing an anteriorly displaced lateralmass that was closer to the midline, broader andmore superior than the contralateral posteriorlydisplaced lateral mass that appeared to be narrowerand further displaced from the midline. The infe-rior border of the posteriorly-displaced lateral masswas obscured by the overlapping ipsilateral superiorC2 articular process (Fig. 1). Axial CT parallel tothe C1 ring clearly depicted C1–C2 rotatorysubluxation (Fig. 2). The anterior displacement ofC1 from C2 was greater than 5 mm, which was,according to the classification of Fielding et al., atype III atlanto-axial rotatory subluxation.

Results

Initially, all patients were treated conservatively withHalter skeletal traction and bedrest. The weightapplied began at 0.5 kg and gradually increased to2 kg until the deformity was successfully reducedand the reduction confirmed by serial antero-poste-rior open-mouth view radiographs. The deformitywas reduced within 2 weeks in all six cases, afterwhich a halo-jacket was applied in cases 1, 3 and 4.

In case 1, the patient was discharged several dayslater without event and the halo-jacket remainedin place for 6 months. No recurrence was seen onregular imaging during the follow-up period of more

than 18 months. In case 2, the deformity wassuccessfully reduced by 6 days of halter traction.The family declined halo-jacket application and thepatient was discharged with a neck collar. Recur-rence of the acute torticollis was noted 6 weeks laterand imaging demonstrated atlanto-axial rotatorysubluxation recurrence. In cases 3 and 4, the halo-jacket was applied for 6 months following successfulreduction of the atlanto-axial rotatory subluxationby halter traction. Unfortunately, acute torticulousdeveloped in both cases several days after the halo-jacket was removed. Follow-up imaging studiesshowed recurrence of the atlanto-axial rotatorysubluxation. Cases 2, 3 and 4 underwent arthrodesisof C1 and C2. No orthosis was used in cases 5 and6, as C1–C2 arthrodesis was performed once theC1–2 rotatory deformity had been successfullyreduced over ten days by halter traction (Table I).They underwent C1–C2 sublaminar wire internalfixation and interlaminar, interspinous allograftbone fusion. Neither mortality nor major morbiditywas noted in any of the cases that had undergonesurgery. The postoperative course was uneventful,and patients were symptom- and sign-free duringthe follow-up period of more than 18 months.

TABLE I. Basic clinical data and treatment of patients

Sex Age (years)Delayed in diagnosis Halter-traction Reduction Orthosis Recurrence

C1–C2 arthrodesis

Case 1 M 9 2 months 0.5 kg 14 days Halo-jacket — —Case 2 F 7 5 months 2 kg 6 days None 6 weeks +Case 3 F 10 6 weeks 1 kg 11 days Halo-jacket 6 months +Case 4 M 12 7 weeks 1.5 kg 12 days Halo-jacket 6 months +Case 5 F 7 3 months 1 kg 10 days None — +Case 6 M 9 3 months 1 kg 11 days None — +

FIG. 1. Open-mouth radiograph of case 4 before skeletaltraction.

FIG. 2. Axial CT scan of C1–C2 in the same case beforeskeletal traction.

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Page 3: Atlantoaxial rotatory subluxation in skeletally immature patients

156 S.-C. Lee et al.

Discussion

Atlanto-axial rotatory subluxation in children usuallyfollows retropharyngeal inflammation or minortrauma, with some having no known aetiology.1–5

Acute torticollis and atlanto-axial subluxationresulting from infection of the head or neck in previ-ously healthy patients was described by Grisel in1930, and is referred to as Grisel’s syndrome.6

Typically, the patient’s head is rotated to one sideand tilted to the opposite side, often with slightcervical flexion, in a manner likened to that of a robinlistening for a worm.2 Wesley W. Parke et al. gave ananatomical explanation for the atlanto-axial hyper-aemia of Grisel’s syndrome in the direct connectionof the periodontoidal venous plexus to the suboccip-ital epidural sinuses via the pharyngovertebralveins, which may allow haematogenous transport ofperipharyngeal septic exudates and neoplastic cells tothe upper cervical spinal structures.7

Rotatory subluxations of C1–C2 are often easilycorrected. In certain rare circumstances, they canpersist and cause torticollis that is resistant totreatment. If there is fixed rotatory subluxation,skeletal skull traction of some form should beapplied and the reduction maintained with someform of immobilization, such as continued tractionor a Minerva jacket, maintained for 3 months.Fielding & Hawkins devised a classification schemefor atlanto-axial rotatory subluxation. Type Irotatory subluxation is characterized by rotatorysubluxation without anterior shift of the atlas. It isthe most common type seen in paediatric age groupsand is the most benign because the transverseligament is intact. Type II consists of rotatorysubluxation with an anterior shift of more than3 mm, but less than 5 mm and is more dangerous asit involves a compromised transverse ligament.Type III involves rotatory subluxation with ananterior shift more than 5 mm. Type IV involvesrotatory subluxation with a posterior shift. Type IIIand type IV deformities are rare, and may be associ-ated with neurological deficits or death. Fielding &Hawkins recommended that patients with subluxa-tion of more than 3 months duration were probablybest treated by fusion, while those with rotatorysubluxation of less than 3 months duration shouldbe treated initially with conservative methods.3,6

The treatment of C1–C2 rotatory subluxationis made more difficult by delays in diagnosis.2–5,8

The diagnosis requires a certain degree of suspicionbased on clinical symptoms and examination.9

Fielding & Hawkins reported that the average delayuntil correct diagnosis was 11.6 months.3 For thecases in our study, the delay until diagnosis rangedbetween 6 weeks and 5 months. Radiographicevaluation of these rotatory subluxations can bechallenging because of the difficulties in takingadequate cervical spine radiographs. Although a

lateral radiograph may sometimes show the firstcervical vertebra rotated on the second,2–4 it is notalways helpful. The lateral view cervical spine radi-ograph may not show any abnormality, especiallyif the injury was not the result of a traumaticepisode.2,5,9 This is particularly so in childrenwith unresolved torticollis who can be difficult toposition and whose radiographs can be difficultto interpret.1–5,8–10 Wortzman & Dewar’s publishedcriteria for fixed atlanto-axial rotatory subluxationwere odontoid-lateral mass asymmetry and theinability of 15º of head rotation in either directionto correct the asymmetry. Additionally, thereshould be no radiographic evidence of fractured,congenitally abnormal or anterior displacement ofthe atlas on the axis.8 Nevertheless, according tothe study of Lee et al., odontoid asymmetry notedon anteroposterior open-mouth radiographs is acommon finding and probably a normal variant. Inaddition, the use of 15º of head rotation to docu-ment fixation of atlantoaxial rotatory subluxationappears to be inadequate.11 CT of the cervical spinehas been shown to be valuable, providing therequired information with minimal patient discom-fort. For the difficult cases, computed tomographyoffers a reasonable alternative to more standardroentgenographic studies and has distinct andunique advantages.10,12 Sagittal and coronalcomputer reconstructed CT images also provideuseful three-dimensional orientation information,but the resolution is not as fine as in transaxial CTstudies.13 Three-dimensional CT can provide moredirect visualization of the area, making definitivediagnosis easy.

In case 1 of our study, the diagnosis was delayedby 2 months and conservative treatment was quitesuccessful. In contrast, the diagnosis was delayedby 5 months in case 2 and the patient failed tomaintain correction after conservative treatment.Both treatment outcomes were in keeping with thefindings of Fielding & Hawkins.2,3 In cases 3 and 4,the patients’ diagnoses were delayed by only 6 weeksand 7 weeks, respectively, as opposed to the 3-monthcritical limit of Fielding & Hawkins, but symptomsrecurred after 6 months of traction and immobiliza-tion, ultimately requiring C1–C2 arthrodesis. Giventhe experiences with cases 3 and 4, we decided totreat C1–C2 rotatory subluxation surgically in caseswith delays in diagnosis of less than 3 months. Incases 5 and 6, both patients had delays in diagnosisof 3 months, which was the borderline requirementfor surgical treatment described by Fielding &Hawkins.2,3 We performed C1–C2 arthrodesis afterthe rotatory subluxation had been corrected by trac-tion. Neither recurrence nor major complicationswere noted during the follow-up period.

Generally speaking, posterior fusion of the uppercervical spine in children and adolescents is a safeand effective procedure. A retrospective review of 17

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immature patients who underwent posterior spinalfusion of C1–C2 or C1–C3 reported two cases ofresidual neurological deficit in the late postoperativeperiod. These two represented preventable technicalerrors.14 Given the limited number of cases in thisstudy, one cannot conclude with certainly that thedelay in diagnosis directly influenced the rate ofrecurrence following conservative treatment. Never-theless, delays in diagnosis of more than 6 weeksappeared to increase the risk of recurrence despitesuccessful reduction with traction and immobiliza-tion over 6 months with a halo-jacket. Moreover,there is both physiological and psychologicalsuffering for a child to have a halo-jacket for6 months. Compliance for a child to have a rigidexternal orthosis is usually poor. Our patients wererecommended to have Miami-J neck collar externalfixation for two months after C1–C2 arthrodesis,and all of them tolerated well.

In conclusion, atlanto-axial rotatory subluxationin children is a disorder that can easily go unrecog-nized.1–5,8–10 Delayed diagnosis has been reportedto be one of the major causes of recurrence.1–5,8–12

Timely cervical spine imaging including anteropos-terior open-mouth radiographs and CT can assistdiagnosis.1–5,8–12 Previous reports recommendedarthrodesis for cases of fixed atlanto-axial rotatorysubluxation of more than three months duration.2–4

In our experience, fixed type III atlanto-axial rota-tory subluxation of less than 3 months durationstill poses a risk of recurrence, even after conserva-tive treatment lasting 6 months. Since posteriorfusion of C1–C2 in children is a safe and effectiveprocedure,3,4,14 we recommend more aggressivesurgical treatment of type III atlantoaxial rotationalsubluxations in patients in whom the diagnosis wasdelayed by more than 6 weeks so that recurrencecould be prevented.

References

1 Edaie PA, Moran R, Fogarty EE, Edwards GE. Rota-tory atlantoaxial subluxation following pharyngoplasty.Br J Plast Surg 1989;42:722–3.

2 Fielding JW, Francis WR, Hawkins RJ, HenisingerRN. Atlantoaxial rotatory deformity. Semin Spine Surg1991;3:33–8.

3 Fielding JW, Hawkins RJ. Atlanto-axial rotatoryfixation. J Bone Jt Surg 1977;59A:37–44.

4 Georges Y, El-Khoury GY, Clark CR, Gravett AW.Acute traumatic rotatory atlanto-axial dislocation inchildren, a report of three cases. J Bone Jt Surg 1984;66A:774–7.

5 Oberthaleer W, Schwarz E. Delayed diagnosis ofa spontaneous atlanto-axial rotatory dislocation. ArchOrthop Trauma Surg 1984;103:212–4.

6 Grobman LR, Stricker S: Grisel’s syndrome. Ear NoseThroat J 1990;69: 799–801.

7 Parke WW, Rothman RH, Brown MD. The pharyn-govertebral veins: an anatomical rationale for Grisel’ssyndrome. J Bone Joint Surg 1984;66A:568–74.

8 Wortzman G, Edwar FP. Rotatory fixation of theatlantoaxial joint: rotational atlantoaxial subluxation.Radiology 1968;90:479–87.

9 Levine AM, Edwards CC. Traumatic lesions of theoccipitoatlantoaxial complex. Clin Orthop Rel Res1989;239:53–68.

10 Fielding JW, Stillwell WT, Spyropoulos EC. Use ofcomputed tomography for the diagnosis of atlanto-axial rotatory fixation. A case report. J Bone Jt Surg1978;60A:1102–4.

11 Lee S, Joyce S, Seeger J. Asymmetry of the odontoid-lateral mass interspaces: a radiographic finding ofquestionable clinical significance. Ann Emerg Med1986;15:1173–6.

12 Geehr RB, Rothman SLG, Kier EL. The role ofcomputed tomography in the evaluation of uppercervical spine pathology. Comput Tomog 1978;2: 79–97.

13 McAfee PC, Bohlman HH, Han JS, Salvagno RT.Comparsion of nuclear magnetic resonance imagingand computed tomography in the diagnosis ofupper cervical spinal cord compression. Spine 1986;11:295–304.

14 Smith MD, Phillips WA, Hensinger RN. Fusion of theupper cervical spine in children and adolescents, ananalysis of 17 patients. Spine 1991;16:695–701.

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