Surgical treatment of myelopathy caused by prior, Indirect decompression for a prior severe C1 2 dislocation causing progressive quadriparesis

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1 J Neurosurg Spine 20: , 2014 AANS, 2014 Indirect decompression for a prior severe C1 2 dislocation causing progressive quadriparesis Case report Kyeong Hwan Kim, M.D., Ph.D., 1 Dong Bong Lee, M.D., 2 Ho-Joong Kim, M.D., 2 K. Daniel Riew, M.D., 3 Boo Seop Kim, M.D., 1 Bong-Soon Chang, M.D., 4 Choon-Ki Lee, M.D., 4 and Jin S. Yeom, M.D. 2 1 Spine Center and Department of Orthopaedic Surgery, Hyundae General Hospital, Namyangju, Korea; 2 Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam, Korea; 3 Department of Orthopaedic Surgery, Washington University in St. Louis, Missouri; and 4 Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Korea Combined anterior and posterior surgery is frequently chosen for the treatment of prior, severe C1 2 dislocations that occurred during early childhood because of the difficulty in achieving reduction and satisfactory decompression. The authors treated a prior, severe C1 2 dislocation that was causing progressive quadriparesis. The patient was a 14-year-old boy who had suffered a C1 2 fracture-dislocation at 3 years of age and had been treated with a Minerva body jacket cast. The treatment involved posterior C1 2 segmental screw fixation, without direct bone decompression or additional surgery. Satisfactory neural decompression was achieved with the techniques used, and complete bone union was confirmed. The patient showed satisfactory neurological recovery at the 5-year follow-up assessment. ( Key Words dislocation indirect decompression quadriparesis cervical Surgical treatment of myelopathy caused by prior, neglected C1 2 dislocations that occurred during early childhood is challenging. Reduction of the dislocated facet joints, which is required for adequate cord decompression, is difficult because of soft-tissue contracture and bone deformities. Anterior surgery, including transoral resection of the odontoid process and/ or release of the facet joint capsules and surrounding soft tissues, combined with posterior fixation and fusion is frequently chosen. 1,9,12,15 However, these methods frequently lead to high rates of morbidities or complications and frequently require combined posterior fixation and fusion. 10,17,21 If posterior surgery alone is chosen, C-1 posterior arch resection may be required because of the difficulty in achieving adequate reduction and spinal cord decompression. However, even this procedure may not provide satisfactory neural decompression in cases with severe kyphotic deformity. In addition, this procedure can result in fusion bed deficiency and may require extension of the fusion level up to the occiput. Although Li et al. 11 reported favorable outcomes with indirect posterior decompression and posterior fusion in patients with prior C1 2 dislocations, the treatment of extremely deformed, prior C1 2 dislocations using posterior C1 2 segmental screw fixation and fusion alone has been rarely reported. 6,7 In this paper we report the case of a patient with a prior, neglected C1 2 dislocation with extremely severe bone deformities that were causing progressive quadriparesis. Satisfactory reduction of the dislocation and decompression of the spinal cord was achieved using posterior C1 2 segmental screw fixation and fusion without direct decompression by bone resection. Informed consent was obtained from the patient and his parents. Case Report History and Presentation. A 14-year-old boy presented with progressive quadriparesis. He had a history of an odontoid process fracture and C1 2 dislocation that occurred when he was 3 years old; this condition had been treated with a Minerva body jacket cast after manual reduction. The patient had grown relatively well, without significant neurological sequelae, until 2 years before presentation. At that time, he first experienced weakness on This article contains some figures that are displayed in color on line but in black-and-white in the print edition. 709

2 K. H. Kim et al. his right side, which slowly progressed to quadriparesis. The quadriparesis was aggravated after a slip injury that occurred 4 weeks before presentation. Upon examination, the patient s extremities displayed hyperactive deep tendon reflexes. Ankle clonus was sustained on the right side and unsustained on the left side. The Babinski sign, finger escape sign, and grip and release test were positive on the right side. His motor power in the upper and lower extremities was between Grades 2 and 4. Independent standing and the use of chopsticks were impossible. Dynamic radiographs showed rigid C1 2 dislocation (Fig. 1A and B), without motion. A CT scan showed that C-1 was dislocated ventrally and caudally, and was pseudoarticulated with C-3 on the right side (Fig. 2A and B). Magnetic resonance imaging revealed that the spinal cord was severely compressed between the odontoid stump and the C-1 posterior arch (Fig. 2C). His Japanese Orthopaedic Association scale and Neck Disability Index scores were 10 and 46, respectively. Operative Course. Preoperative 8-pound traction was applied for 24 hours using Gardner-Wells tongs. Surprisingly, a partial but significant amount of reduction was achieved, even with this small amount of traction (Fig. 1C). Therefore, the surgeon (J.S.Y.) concluded that satisfactory reduction would be possible during surgery. Under general anesthesia, the patient was placed prone with 16-pound traction using Gardner-Wells tongs. With a posterior approach and bilateral transection of the C-2 nerve roots, the C1 2 facet joints were opened, and the hypertrophied intraarticular soft tissues and articular cartilage were removed with a high-speed drill bur, curettes, and micropituitary forceps. During this procedure, various sizes of Penfield retractors and suction tips were used to distract the joint space using craniocaudal leverage. We were able to mobilize the facet joint and thus facilitate the subsequent reduction maneuver. Although the severe anterior tilt of the facet joint surfaces (Fig. 2B) precluded intraarticular preparation for fusion and reduction, resection of the articular process was not performed because it could possibly lead to collapse of the remaining weak cancellous bone during reduction or follow-up. Autologous cancellous chips harvested from the posterior iliac crest were inserted in the facet joint space for intraarticular fusion. Then, before reduction was attempted, C-1 lateral mass screws and C-2 pedicle screws were inserted under fluoroscopic control (Fig. 3 left). Computer imageguided surgery was not used. Temporary rods with sufficient lengths to connect the C-1 and C-2 screw heads, which were far away from each other at this time (Fig. 3 left), were loosely secured with set screws. Reduction was achieved by pulling the C-1 screw heads posteriorly and pushing C-2 screw heads anteriorly 16 using rod holders, and craniocaudal compression between the C-1 and C-2 screw heads with a compressor. While maintaining this maneuver, set screws were tightened on both sides. Then the set screws were loosened on one side. We then further compressed between the C-1 and C-2 screws while pulling the C-1 screw posteriorly and pushing the C-2 screw anteriorly. After this reduction maneuver, the set screws were tightened. This was alternately repeated on each side under intermittent lateral fluoroscopic control (Fig. 3 right). Fluoroscopy revealed progressive reduction as this maneuver was repeated. When the C-1 posterior arch and the C-2 lamina contacted each other and further compression was impossible, the reduction maneuver was stopped and the temporary rods were replaced with final rods with shorter lengths, one at a time. An autologous bone graft harvested from the iliac crest was grafted for extraarticular and posterior fusion. Intraoperative neuromonitoring was not used because it was not available. Postoperative Course. Sufficient cord decompression was confirmed by postoperative CT myelography (Fig. 4 left). A Miami collar was used for 3 months. The patient s myelopathy improved gradually, and independent gait was possible 6 weeks after surgery. The patient enjoyed a normal life and could exercise with moderate intensity 5 years after surgery, and the reduction was well maintained (Fig. 4 right). His Japanese Orthopaedic Association scale and Neck Disability Index scores were 16 and 12, respectively. Discussion Sufficient cord decompression, satisfactory reduction, and rigid fixation, along with solid bone union are Fig. 1. Preoperative radiographs. Flexion (A) and extension (B) lateral radiographs show no motion. The posterior atlantodental interval (between arrowheads) was 5 mm on both views. A lateral radiograph obtained after 18 hours of 8-pound skeletal traction (C) shows significant reduction with a 12-mm posterior atlantodental interval (between arrowheads). 710

3 Indirect decompression for prior C1 2 dislocation Fig. 2. Preoperative imaging studies. On 3D CT scans (A and B), the dislocated C-1 inferior articular process showed pseudoarticulation with the C-3 vertebral body on the right side (arrowheads). A T2-weighted sagittal MR image (C) shows severe cord compression (arrowheads) and an anteriorly displaced odontoid process (arrow). the major goals in the treatment of C1 2 dislocations. Acute dislocation of the C-1 and C-2 joints may be reduced without obvious difficulty. However, in cases of severe cord compression and myelopathy due to prior C1 2 dislocations, particularly ones that occurred during early childhood, effective cord decompression using reduction alone, without bone resection, is difficult to achieve. Contracture of soft tissues and severe bone deformities frequently inhibit restoration of proper alignment. Therefore, some authors have reported direct decompression, with removal of the odontoid process via an anterior approach, with or without posterior fixation.1,9,12,15 However, this approach provides a narrow operative field and may result in complications such as infection, nonunion, vertebral artery rupture, and dural tears.2,10,17,21 Wang et al.18 advocated soft-tissue release via a transoral approach, without odontoid removal, combined with posterior fixation and fusion. To avoid the disadvantages of the anterior approach, the posterior approach with a C-1 posterior arch resection was reported,13 but effective fixation of dislocation and bone union is difficult to achieve, and occipitocervical instability may occur. Li et al.11 reported favorable results for indirect decompression without C-1 posterior arch resection via a posterior approach in prior C1 2 dislocations. These authors used skeletal traction as the main technique for reduction, and posterior instrumentation was added for maintenance of the reduction. However, they did not mention whether they achieved successful results in extremely severe cases. The current case showed severe cord compression. In addition, C1 2 dislocation was accompanied by severe deformation of the C1 2 facet joints, and the right inferior articular process of C-1 had pseudoarticulated with C-3, a condition that should not normally exist. Fortunately, partial reduction was achieved with preoperative skeletal traction, thus demonstrating a high probability of further reduction with the application of greater reduction force during surgery. The use of segmental screw fixation allows application of a strong reduction force during rod assembly after screw placement has been completed. In the current case, this method enabled satisfactory indirect decompression of the spinal cord without direct removal of bone structures or additional anterior surgery. In addition, occipitocervical fusion was avoided because the posterior arch of C-1 was not resected. Thus, the patient was effectively treated with indirect decompression and Fig. 3. Intraoperative fluoroscopic images obtained before (left) and after (right) the reduction maneuver performed during rod assembly. 711

4 K. H. Kim et al. Fig. 4. Postoperative CT myelography (left) showing complete decompression of the spinal cord (arrowhead), and a lateral radiograph obtained at the 5-year follow-up assessment (right) showing the maintenance of reduction with complete bone union (arrowhead). C1 2 segmental screw fixation, without either bone resection or additional anterior surgery. Goel et al. reported a technique for reduction of irreducible dislocations using intraoperative traction, transection of the C-2 nerve roots, opening of the joints, and segmental fixation of the atlas and axis. 7 They extensively removed the articular surface of the C-1 and C-2 facets using a microdrill, distracted the facets using an intervertebral spreader, and inserted hydroxyapatite blocks or titanium spacers and bone graft in the facets. The final reduction was achieved using a plate and segmental screws. Similar techniques were used for the treatment of basilar invagination and fixed atlantoaxial dislocation in cases with congenital anomalies and in cases of rheumatoid arthritis by the same author group. 5,6,8 While their principle of reduction included distraction of the facet joint, we obtained reduction by compression between the C-1 and C-2 screw heads. The posterior aspect of the C-1 inferior and the C-2 superior articular processes worked as a fulcrum during the reduction procedure, leading to distraction of the anterior soft tissues. In addition, whereas Goel et al. first tightened axial screws and then tightened the atlantal screws using plate-and-screw constructs to obtain reduction, we obtained reduction by pulling the C-1 screw heads posteriorly and pushing the C-2 screw heads anteriorly, similar to the technique described by Suh et al. 16 These maneuvers were repeated alternately on each side until acceptable reduction was achieved, which can be attained with polyaxial screw-rod systems but not with plate-andscrew systems. Three types of screws are commonly used for posterior segmental screw fixation of C-2. The principles of placing a C-2 pars screw are similar in most aspects to posterior transarticular screw placement, except that the length of the pars screw is significantly shorter so as to avoid the vertebral artery foramen. 3,20 The C-2 pedicle screw has a less cephalad and more medial angulation and is longer than a pars screw. 3,14 In this case, we chose to use pedicle screws because they have longer purchase in C-2, providing greater stability than pars screws. 4 Translaminar screws 19 may be used if the anatomy precludes placement of pedicle and pars screws. However, assembly of those screws to the rods may not be easy and application and maintenance of a sufficient amount of reduction force may be challenging. 16 For this reason we did not choose translaminar screws in this case. Computer image-guided surgery and intraoperative neuromonitoring may enhance the accuracy of screw placement and decrease the risk of neurovascular injuries, although they were not used in this case. The findings of the present case suggest that indirect decompression with C1 2 segmental screw fixation is helpful for patients who can accommodate the segmental screw trajectories, who have shown partial reduction with preoperative traction, and who have satisfactory bone quality to prevent bone failure during reduction or screw loosening. However, we are not sure about the results of posterior surgery alone in those patients who cannot accommodate such screws, who do not show even partial reduction with preoperative traction, or who have poor bone quality to endure a significant amount of reduction force or to maintain reduction after surgery without screw loosening. Further research is required to define the proper indications for the technique reported in the present study and to preoperatively predict the necessity of additional anterior release or direct decompression. Acknowledgments We thank and acknowledge Ms. Yoon Ju Kwon and Ms. Junga Park, the spine research coordinators at our institution, for their contributions to the project. 712

5 Indirect decompression for prior C1 2 dislocation Disclosure Dr. Riew has direct stock ownership in Expanding Orthopedics, Amedica, Benvenue, Nexgen Spine, Osprey, Paradigm Spine, Spinal Kinetics, Spineology, and Vertiflex; has received clinical or research support for this study from AOSpine, Cerapedics, Spinal Dynamics, and Medtronic; has received fellowship funding, compensation as Chair of the Research Commission on the International Board, and reimbursement for travel expenses for multiple courses and board-related meetings from AOSpine; and has been reimbursed for expenses by the New England Spine Society Group, Dubai Spine Society, Spine Masters, and Broadwater for speaking and/or teaching courses. Dr. Yeom has received fees from Medtronic for lectures in the company s cadaver workshop for surgeons. Author contributions to the study and manuscript preparation include the following. Conception and design: Yeom, KH Kim, DB Lee, Riew, BS Kim, Chang. Acquisition of data: KH Kim, DB Lee. Analysis and interpretation of data: KH Kim, DB Lee, HJ Kim. Drafting the article: KH Kim, DB Lee, HJ Kim. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Yeom. Study supervision: Riew, Chang, CK Lee. References 1. Bhangoo RS, Crockard HA: Transmaxillary anterior decompressions in patients with severe basilar impression. Clin Orthop Relat Res (359): , Bonney G, Williams JP: Trans-oral approach to the upper cervical spine. A report of 16 cases. J Bone Joint Surg Br 67: , Bransford RJ, Lee MJ, Reis A: Posterior fixation of the upper cervical spine: contemporary techniques. J Am Acad Orthop Surg 19:63 71, Dmitriev AE, Lehman RA Jr, Helgeson MD, Sasso RC, Kuhns C, Riew DK: Acute and long-term stability of atlantoaxial fixation methods: a biomechanical comparison of pars, pedicle, and intralaminar fixation in an intact and odontoid fracture model. Spine (Phila Pa 1976) 34: , Goel A: Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation. J Neurosurg Spine 1: , Goel A, Kulkarni AG, Sharma P: Reduction of fixed atlantoaxial dislocation in 24 cases. Technical note. J Neurosurg Spine 2: , Goel A, Muzumdar D, Dange N: One stage reduction and fixation for atlantoaxial spondyloptosis: report of four cases. Br J Neurosurg 20: , Goel A, Sharma P: Craniovertebral realignment for basilar invagination and atlantoaxial dislocation secondary to rheumatoid arthritis. Neurol India 52: , Hadley MN, Spetzler RF, Sonntag VKH: The transoral approach to the superior cervical spine. A review of 53 cases of extradural cervicomedullary compression. J Neurosurg 71: 16 23, Jain VK, Behari S, Banerji D, Bhargava V, Chhabra DK: Transoral decompression for craniovertebral osseous anomalies: perioperative management dilemmas. Neurol India 47: , Li XF, Yang HL, Jiang WM, Tang TS, Gong XH, Yuan J, et al: Combination of skull traction with posterior C1-2 fusion for old C1-2 dislocations. J Clin Neurosci 18: , Menezes AH, VanGilder JC: Transoral-transpharyngeal approach to the anterior craniocervical junction. Ten-year experience with 72 patients. J Neurosurg 69: , Stanley D, Laing RJ, Forster DM, Getty CJ: Posterior decompression and fusion in rheumatoid disease of the cervical spine: redressing the balance. J Spinal Disord 7: , Stock GH, Vaccaro AR, Brown AK, Anderson PA: Contemporary posterior occipital fixation. J Bone Joint Surg Am 88: , Subin B, Liu JF, Marshall GJ, Huang HY, Ou JH, Xu GZ: Transoral anterior decompression and fusion of chronic irreducible atlantoaxial dislocation with spinal cord compression. Spine (Phila Pa 1976) 20: , Suh BG, Padua MR, Riew KD, Kim HJ, Chang BS, Lee CK, et al: A new technique for reduction of atlantoaxial subluxation using a simple tool during posterior segmental screw fixation. Clinical article. J Neurosurg Spine 19: , Tuite GF, Veres R, Crockard HA, Sell D: Pediatric transoral surgery: indications, complications, and long-term outcome. J Neurosurg 84: , Wang C, Yan M, Zhou HT, Wang SL, Dang GT: Open reduction of irreducible atlantoaxial dislocation by transoral anterior atlantoaxial release and posterior internal fixation. Spine (Phila Pa 1976) 31:E306 E313, Wright NM: Posterior C2 fixation using bilateral, crossing C2 laminar screws: case series and technical note. J Spinal Disord Tech 17: , Yanni DS, Perin NI: Fixation of the axis. Neurosurgery 66 (3 Suppl): , Zileli M, Cagli S: Combined anterior and posterior approach for managing basilar invagination associated with type I Chiari malformation. J Spinal Disord Tech 15: , 2002 Manuscript submitted January 18, Accepted February 24, Please include this information when citing this paper: published online March 28, 2014; DOI: / SPINE1352. Address correspondence to: Jin S. Yeom, M.D., Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-ku, Sungnam , Republic of Korea. highcervical@gmail.com. 713