Surgical Neurology 66 (2006) 311 – 314 www.surgicalneurology-online.com
Technique
Halo traction in basilar invagination: technical case report Serkan Simsek, MD, Kazim Yigitkanli, MD4, Deniz Belen, MD, Murad Bavbek, MD Neurosurgery Department, Ministry of Health, Diskapi Educational and Research Hospital, Ankara 06110, Turkey Received 24 November 2005; accepted 19 December 2005
Abstract
Background: In the management of basilar invagination, traction therapy may help by pulling down the odontoid process away from the brain stem that may result in clinical and radiological improvement. We aimed to discuss the role of the halo vest apparatus traction on the reduction of severe anterior compression pathologies in basilar invagination. Case Description: We describe a simple and safe cervical traction method by the halo vest apparatus that is followed by rigid posterior occipitocervical fixation and foramen magnum decompression in a patient who presented with basilar invagination and symptoms of severe brain stem compression. An MR-suitable halo vest apparatus was used for reduction of the deformity. The reduction of the basilar invagination was achieved gradually by distracting the halo crown in stages. Conclusion: The halo vest apparatus can be safely used in complex craniocervical junction anomalies. An effective cervical traction can be performed in basilar invagination, and reduction of the deformity may be achieved without the risk of overdistraction. In some cases, even partial reduction of the deformity may facilitate brain stem and spinal cord relief without any need of posterior decompression. Patients may benefit from ambulatory functions because bed rest is eliminated in this procedure. Neurovascular structures and the degree of the reduction can be observed on MRIs when an MR-suitable device is used. D 2006 Elsevier Inc. All rights reserved.
Keywords:
Atlantoaxial dislocation; Basilar invagination; Cervical traction; Craniocervical fixation; Halo vest apparatus
1. Introduction Basilar invagination is a primary developmental anomaly that compresses the ventral brain stem and the upper spinal cord. The early surgical treatment of this pathology incorporated enlargement of the foramen magnum and removal of the posterior arches of the atlas and axis. In recent decades, with a better understanding of craniocervical dynamics, the mostly preferred operative procedures have been anterior decompression or circumferential decompression procedure followed by posterior fixation [2-4,6,12,14,17]. Here, we report a case of basilar invagination and atlantoaxial dislocation, in which partial reduction was
Abbreviations: CT, computerized tomography; CVJ, craniovertebral junction; JOA, Japan Orthopedic Association; MRI, magnetic resonance imagination. 4 Corresponding author. Sag˘lVk BakanlVg˘V DVYkapV YVldVrVm BeyazVt Eg˘itim ve AraYtVrma Hastanesi, 2.Beyin Cerrahisi Klinig˘i, Ankara. Tel.: +90 312 317 05 05/1390; fax: +90 312 517 31 44. E-mail address:
[email protected] (K. Yigitkanli). 0090-3019/$ – see front matter D 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2005.12.029
achieved stepwise under cervical traction by using the halo vest apparatus. After the desirable improvement of the
Fig. 1. Preoperative T1-weighted image revealing basilar invagination, fixed atlantoaxial dislocation, and severe compression of the brain stem.
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Fig. 2. Preoperative sagittal CT reconstruction scan shows marked basilar invagination and fixed atlantoaxial dislocation.
pathology had been achieved, foramen magnum decompression and posterior occipitocervical fixation were performed under the halo traction force. To the best of our knowledge, halo vest traction in the reduction of basilar invagination has not been the focus of a particular report. 2. Case report A 49-year-old woman presented with a 6-year history of paresthesia in all 4 limbs. For the last 3 years, she had neck pain and stiffness in all 4 limbs, which increased gradually. For the last 2 years, she had difficulty in walking and had bladder urgency. On her physical examination, short neck with low hairline and restricted neck movements were observed. Her neurological examination disclosed spastic quadriparesis (motor strength 3/5), with a JOA score of 6. Plain cervical radiographs and CT demonstrated cranial settling of odontoid process, atlantoaxial dislocation with occipitalized atlas, and fusion of C2-C3 and C5-C6 vertebra
(Fig. 1). On dynamic radiographs, no atlantoaxial instability was seen. MRI of the CVJ revealed tilted and posteriorly angulated odontoid process, which caused brainstem compression. At cervical level syrinx in the spinal cord was observed (Fig. 2). For the management of the pathology, a decision of stepwise distraction with halo vest apparatus was made. Upon applying the MR-suitable halo vest apparatus to the patient, the halo crown was distracted every other day by turning the screw bolts that hold the halo ring. After each cycle, the neurological, radiological, and skin conditions of the patient were checked. At the end of 4 weeks, the degree of reduction was confirmed by CT and MRI (Fig. 3A and B). Significant radiological and clinical improvements were observed. By that time, the JOA score of the patient was 10. At the same time, the patient underwent surgery in prone position. The procedure was carried out under the halo traction force. The apparatus was easily adjusted to the head fixation system of the operating table. A posterior occipitocervical fixation with rod-plate system (Vertex, Medtronik Sofamor Danek; occiput-C3 pedicle and C4 lateral mass) was performed. Auto- and allograft bone chips were placed over the drilled occipital bone and cervical laminae after posterior decompression of the occiput and resection of the posterior arch of the atlas had been made. The patient was kept in halo traction for more than 3 months after the surgery. On the follow up examination by the fourth month, the patient’s JOA score was 16 and the halo jacket was removed. By the end of the first year, the patient experienced an accidental trauma to her neck that resulted in acute neurological worsening. At this second admittance to our institution, her JOA score was assessed as 8, and she suffered from severe neck pain. Plain radiograms of the CVJ showed loosening of the occipital screws. Impingement of the brainstem by the odontoid process was seen on the MRI. Diagnosis of failure of the occipitocervical implant was made, and the patient was reoperated under the same halo
Fig. 3. Posttraction, sagittal CT reconstruction (A) and MR image (B) demonstrating reduction of the basilar invagination and also atlantoaxial dislocation.
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Fig. 4. Lateral sagittal T1-weighted MRI (A) and occipitocervical radiogram (B) obtained 8 months after the second operation showing decompression of the craniocervical junction deformity.
traction technique, and the loosened occipital screws were replaced more medially with the longer ones (14 mm instead of 8 mm). On first day postoperative, her JOA score increased immediately to 13. During an average of 1-year follow up after the last operation, neither neurological worsening nor implant failure was observed (Fig. 4A and B). Omega angle and atlantodental interval values were toward the reference range (Table 1). No movement was seen on the dynamic radiographs of the CVJ. Her last JOA score was 14. 3. Discussion Congenital CVJ anomalies are complex pathologies involving many surrounding structures of the region. The management of this rare entity, in particular of the basilar invagination, pose difficulty regarding the surgical approach. To date, various surgical methods have been described. Currently, the most preferred technique is anterior decompression with or without fixation of CVJ [3,4,6,12,14]. Some authors recommend only posterior decompression or circumferential decompression as the primary treatment option [2,16,17]. Although neurological improvement is usually observed after an effective anterior decompression, neurological deterioration and respiratory failure in the presence of marked brain stem compression may be the potential risks [3,4,6,12,14]. Moreover, in the absence of strong internal fixation, further cranial settling may be expected after an anterior decompression procedure [5,15]. It has been shown that traction treatment may pull down the odontoid process away from the brain stem in basilar invagination cases, especially in patients without Chiari malformation, and result mostly in clinical and radiological improvement [6]. This observation suggests that a relative vertical instability persists in the craniovertebral region. Goel et al [6] reported 4 patients in whom posterior fixation procedure was performed with in situ reduction of the basilar invagination and atlantoaxial dislocation; however, all the patients needed transoral decompression surgery at a
later stage because the reduced position could not be maintained by the implant. Menezes [13] described significant improvement in basilar invagination and atlantoaxial subluxation cases with traction treatment. Joseph and Rajshekhar [9] reported the case of a patient who presented with basilar invagination, Chiari formation, and syringomyelia, in which the anomalies were resolved under traction therapy without any operative intervention. The halo vest apparatus is simply used for immobilization of the cervical spine and for the management of cervical spine dislocations. Kinnaird and Jelsma [10] used a portable traction device, but their technique needed bed rest. For correction of the cervical deformity, Graziano et al [7] used components of the Ilizarov apparatus, which connects the halo crown to a modified body cast. Kyoshima et al [11] was the first to report a simple cervical traction method with the halo vest apparatus for the unstable CVJ injuries. This technique can provide strong and safe traction that may also be confirmed by MRI. Moreover, bed rest is not necessary during the procedure; it may be an advantageous point for preventing deep venous thrombosis and pulmonary embolism, particularly in elder patients. In the presented case, reduction of the anomaly with the halo traction method confirmed the relative instability of this area. The main problem after this stage was to maintain the reduced position of the basilar invagination and the atlantoaxial dislocation. Keeping this point in mind, a posterior intervention to this region was planned. Table 1 The table shows the patients’ radiological features during the treatment and follow up periods
CL (mm) ADD (mm) Cervicomedullary angle on MRI (8) JOA score
First preoperative
First posttraction
Second postoperative follow up (8 mo)
18 6 100
9 2 162
Not calculated 2 154
5
10
CL, Chamberlein Line; ADD, atlantodental distance.
14
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Occipitocervical fixation is a widely used technique, and its clinical outcome has been reported to be satisfactory in the stabilization of this region [1,8,16]. In the presented case, a strong occipitocervical implant was preferred for the fixation because of the powerful traction force on this area and to avoid further cranial settling. 4. Conclusions We conclude that cervical traction and posterior occipitocervical fixation may be a treatment modality in basilar invagination cases. If the implant could not sustain the reduced position, the anterior decompression may be the second stage of this procedure. The authors also suggest that cervical traction may be safely and strongly performed by using the halo vest apparatus. This technique may provide accurate reduction in complex craniocervical pathologies without the risk of overdistraction. Patients can keep their ambulatory functions properly during the traction procedure. The degree of reduction can also be demonstrated at MRI by using MR-suitable halo vest apparatus.
[10] Kinnaird RH, Jelsma RK. A portable traction device for cervical fractures. Technical note. J Neurosurg 1992;76:544 - 5. [11] Kyoshima K, Kakizawa Y, Tokushige K. Simple cervical spine traction using a halo vest apparatus: technical note. Surg Neurol 2003; 59:518 - 21. [12] Menezes AH, Van Gilder JC. Transoral-transpharyngeal approach to the anterior craniocervical junction. J Neurosurg 1988;69:895 - 903. [13] Menezes AH. Primary cranivertebral anomalies and the hind brain herniation syndrome (Chiari 1): data base analysis. Pediatr Neurosurg 1995;23:260 - 9. [14] Mummaneni PV, Haid RW. Transoral odontoidectomy. Neurosurgery 2005;56:1045 - 50. [15] Naderi S, Pamir MN. Further cranial settling of the upper cervical spine following odontoidectomy. report of two cases. J Neurosurg 2001;95:246 - 9. [16] Nishikawa M, Ohata K, Baba M, Terakawa Y, Hara M. Chiari I malformation associated with ventral compression and instability: one-stage posterior decompression and fusion with a new instrumentation technique. Neurosurgery 2004;54:1430 - 5. [17] Zileli M, Cagli S. Combined anterior and posterior approach for managing basilar invagination associated with type I Chiari malformation. J Spinal Disord Tech 2002;15:284 - 9.
Commentary References [1] Abumi K, Takeda T, Shono Y, Kaneda K, Fujiya M. Posterior occipitocervical reconstruction using cervical pedicle screws and plate-rod systems. Spine 1999;24:1425 - 34. [2] Collignon FP, Cohen-Gadol AA, Krauss WE. Circumferential decompression of the foramen magnum for the treatment of syringomyelia associated with basilar invagination. Neurosurg Rev 2004;27:168 - 72. [3] Crockard HA. The transoral approach to the base of the brain and upper cervical cord. Ann R Coll Surg Engl 1985;67:321 - 5. [4] Crockard HA. Transoral surgery. Some lessons learned. Br J Neurosurg 1995;9:283 - 93. [5] Dickman CA, Crawford NR, Brantley AG, Sonntag VK. Biomechanical effects of transoral odontoidectomy. Neurosurgery 1995;36:1146 - 53. [6] Goel A, Bhatjiwalle M, Deasi K. Basilar invagination:a study on 190 surgically treated patients. J Neurosurg 1998;88:962 - 8. [7] Graziano GP, Herzenberg JE, Hensinger RN. The halo-Ilizarov distraction cast for correction of cervical deformity. Report of six cases. J Bone Joint Surg Am 1993;75:996 - 1003. [8] Grob D, Dvorak J, Panjabi M, Froechlich M, Hayek J. Posterior occipitocervical fusion. A preliminary report of a new technique. Spine 1991;16:S17 - S24. [9] Joseph V, Rajshekhar V. Resolution of syringomyelia and basilar invagination after traction. J Neurosurg (Spine 3) 2003;98:298.
The authors have presented an excellent demonstration of the potential for the reduction of cranial-cervical deformities in an ambulatory halo. The amount of correction, indeed, is dramatic. However, as they also demonstrate, maintaining the reduction in the face of adverse biomechanical forces is quite difficult. I suspect that in the absence of myelopathy, simple occipital to C4 fusion is adequate, perhaps with removal of the arch of C1 and enlarging the foramen magnum. In this instance, however, a transoral approach with its attendant risks was avoided. The key to success is maintaining the reduction long enough for the fusion to heal. Only allograft on the skull has a fairly high nonunion rate, especially in this population. One might consider the use of bone marrow aspirate supplement or electrical stimulation. This is a valuable case report—one that will affect many of our practices. Dennis Jay Maiman, MD, PhD Spinal Cord Injury Center Milwaukee, WI 53226, USA
