- Email: [email protected]
Atlantoaxial stabilization utilizing atlas translaminar fixation
Journal of Clinical Neuroscience 17 (2010) 1578–1580
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Technical Note
Atlantoaxial stabilization utilizing atlas translaminar fixation Ali A. Baaj a,b,⇑, Frank D. Vrionis b,1 a b
Department of Neurosurgery, College of Medicine, University of South Florida, 2A Columbia Drive, Tampa, Florida 33606, USA Department of Neuro-Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
a r t i c l e
i n f o
Article history: Received 28 March 2010 Accepted 4 April 2010 Keywords: Atlas Fusion Metastasis spine tumors
a b s t r a c t Atlantoaxial instability is a potentially devastating sequela of tumor invasion to the upper cervical spine. We aim to report an alternative technique for atlantoaxial stabilization. Stabilization is technically demanding due to limited bony elements and proximity of the regional neurovascular structures. While the C1 lateral masses are considered robust points of fixation, one or both of these structures may be destroyed by pathology. A 54-year-old female presented with a lytic, metastatic lesion to one of the C1 lateral masses, which precluded its use for fixation. We utilized the contralateral hemilamina of the atlas for screw fixation and devised a stable construct that provided immediate stability. Thus, atlas translaminar fixation is a feasible option when the lateral masses cannot be utilized. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Several pathological entities may lead to atlantoaxial instability, including trauma, tumors, and inflammatory conditions. Internal fixation in this region is technically challenging given the small working channels and the proximity of neurovascular structures to the bony elements. Clinically relevant techniques all utilize a combination of screws, hooks, rods or wires.1 The C1 lateral mass/C2 pars screw fixation construct, first reported by Goel and Laheri2 and later popularized by Harms and Melcher,3 is now considered one of the more robust constructs in this region. We present a patient in whom one of the C1 lateral masses was destroyed by an invasive tumor and, to rigidly fixate the atlantoaxial segment, the hemilamina was utilized instead as a fixation point. We believe this is a feasible option where pathology precludes using the C1 lateral mass as a fixation point. 2. Patient details 2.1. History and examination The patient was a 54-year-old female who was diagnosed with invasive ductal cell carcinoma of the left breast 9 years prior to this admission. She had undergone a left-sided lumpectomy followed by chemoradiation. She began to complain of new-onset, debilitating neck pain. She was neurologically intact with the exception of ⇑ Corresponding author. Tel.: +1 813 2590901; fax: +1 813 2590858. 1
E-mail address: [email protected] (A.A. Baaj). Frank D. Vrionis is a consultant for Stryker, Inc.
0967-5868/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2010.04.011
tenderness to palpation in the midline cervical spine. CT scan of the cervical spine revealed a lytic lesion involving the right C1 lateral mass and right hemilamina (Fig. 1). MRI was contraindicated as the patient had a metallic foreign body in her ear. A positron emission tomography (PET) scan demonstrated uptake in the upper cervical spine. Complete metastatic work-up, including neuroaxis imaging, revealed no other lesions.
2.2. Operative technique The patient was taken to the operating room for resection of a presumed metastatic lesion of the cervical spine and stabilization. She was placed in the prone position and 4.54 kg (10 lb) of cervical traction was applied. The atlantoaxial region was dissected and exposed through standard technique. C1 was clearly mobile with respect to C2. The lesion was visualized by the inferior aspect of the right C1 lateral mass region at the C1/C2 articulating joint. The lesion was removed in piece-meal fashion (subtotal resection) and pathology confirmed metastatic breast carcinoma. The third segment (V3) of the vertebral artery was visualized and uninjured. We proceeded to place the C1 lateral mass screw (LM) on the left using established techniques.5,6 Bicortical purchase was achieved. We also placed bilateral C2 pars (PS) and C3 lateral mass screws. As an additional point of fixation, we were able to drill, tap and place a 14 mm by 3.5 mm screw (Stryker; Kalamazoo, MI, USA) in the left hemilamina of the atlas. Bilateral 3.5 mm rods (left: C1 LM, C2 PS, C3 LM; right: C1 translaminar screw, C2 PS, C3 LM) were placed and a crosslink was applied. Allograft was placed over the construct after adequate decortication.
A.A. Baaj, F.D. Vrionis / Journal of Clinical Neuroscience 17 (2010) 1578–1580
Fig. 1. Preoperative axial CT scan of the cervical spine showing the lytic lesion involving the right C1 lateral mass and hemilamina.
2.3. Postoperative course The patient was extubated, placed in an Aspen collar and had no immediate postoperative deficits. Her pain had improved significantly. Postoperative plain radiographs showed adequate hardware placement and cervical alignment (Fig. 2). She was discharge to home 3 days after surgery. She re-presented 6 weeks later with dysphagia but no neurological deficits. Her CT scan (Fig. 3) demonstrated no hardware failure but did show tumor recurrence. She was scheduled for radiation therapy. 3. Discussion Metastatic disease to the spine continues to pose significant challenges to the treating spine surgeon. Despite advances in adju-
Fig. 2. Postoperative anteroposterior plain radiographs showing the C1–C3 construct with adequate hardware placement and cervical alignment.
1579
Fig. 3. Postoperative axial CT scan of the atlas showing the C1 hemilamina screw and no hardware failure.
vant therapy, surgical resection to either confirm suspected pathology, or, more often, to decompress the neural elements, remains the primary treatment modality in many cases. When tumor involves the craniocervical junction, it becomes paramount to not only to decompress, but also to provide immediate stability via internal fixation. Several fixation options have been described for atlantoaxial instability including the Brooks, Gallie, Sonntag wiring techniques, and more recently, the transarticular C1/C2 and the C1 lateral mass/C2 pars screw construct with rods and/or interspinous wiring.2–6 The latter construct (C1 LM/C2 PS) is the senior aurthor’s (FDV) preferred technique for atlantoaxial fixation. In this patient, the metastatic lesion had destroyed the inferior aspect of the right lateral mass of C1, which made placing a screw there impossible. There are several published reports describing fixation techniques when this situation is encountered. After resection of an aneurysmal bone cyst of the atlas, Wang et al.7 reconstructed the right lateral mass of C1 with a titanium mesh cage. The construct was augmented with occipital-C4 screw fixation. In a review article on spine reconstruction after tumor resection, Melcher and Harms8 present a similar case in which a destroyed C1 lateral mass was replaced with a titanium mesh cage. An occipital–cervical (O–C) instrumentation technique was similarly employed to complete the construct. Given the presumed osteopenic bone in our patient with metastatic breast cancer, and future irradiation, subsidence and/or dislodgement of a cage is a realistic possibility and could lead to serious neurovascular complications. We thus opted against placing a cage below the occipital condyle. Floyd and Grob9 previously described translaminar fixation of the atlas. In five patients with deficiency of the C1 posterior arch, the authors placed iliac crest graft posteriorly and fixated the grafts into each hemilamina of C1 with two screws (2.7 mm). The construct was augmented with C1/C2 transarticular screws and posterior wiring. In our patient, the right hemilamina of C1 was removed due to tumor invasion, but the left hemilamina was intact. Under direct visualization, we are able to drill, tap and place the translaminar screw. Equal, and symmetric, fixation would have likely provided
1580
A.A. Baaj, F.D. Vrionis / Journal of Clinical Neuroscience 17 (2010) 1578–1580
for a more biomechanically sound construct. This patient may develop muscular compensatory mechanisms away from the weak side (the right in this patient) which may lead to neck pain. Given the limited bony elements, however, and given the need for providing immediate stabilization, we determined that providing an additional point of fixation in the form of a translaminar atlas screw was warranted. Although extending the construct to the occiput would have been reasonable, we opted to spare the atlantooccipital motion segment. We appreciate the biomechanical significance of restoring the load-bearing property of the C1 lateral mass-occipital condyle complex, but we felt that a stable atlantoaxial construct with adequate occipitocervical alignment on preoperative films justified our decision not to fuse O–C1. In our experience, O–C constructs carry a lower fusion rate when compared to atlantoaxial techniques and also considerably limit patients’ range of motion. 4. Conclusions Atlantoaxial fixation is challenging. When pathology, such as tumor, destroys the bony elements in this region, the options for
fixation points become even more limited. The hemilamina of the atlas may by utilized as an additional point of fixation when clinically warranted. This could be part of an atlantoaxial or occipitocervical construct. Long-term efficacy and biomechanics of this technique need to be examined. References 1. Mummaneni PV, Haid RW. Atlantoaxial fixation: overview of all techniques. Neurol India 2005;53:408–15. 2. Goel A, Laheri V. Plate and screw fixation for atlanto-axial subluxation. Acta Neurochir (Wien) 1994;129:47–53. 3. Harms J, Melcher RP. Posterior C1–C2 fusion with polyaxial screw and rod fixation. Spine 2001;26:2467–71. 4. Brooks AL, Jenkins EB. Atlantoaxial arthrodesis by the wedge compression method. J Bone Joint Surg Am 1978;60A:279–84. 5. Dickman CA, Sonntag VK, Papadopoulos SM, et al. The interspinous method of posterior atlantoaxial arthrodesis. J Neurosurg 1991;74:190–8. 6. Gallie WE. Fractures and dislocations of cervical spine. Am J Surg 1939;46:495–9. 7. Wang VY, Deviren V, Ames CP. Reconstruction of C-1 lateral mass with titanium mesh cage after resection of an aneurysmal bone cyst of the atlas. J Neurosurg Spine 2009;10:117–21. 8. Melcher RP, Harms J. Biomechanics and materials of reconstruction after tumor resection in the spinal column. Orthop Clin North Am 2009;40:65–74. 9. Floyd T, Grob D. Translaminar screws in the atlas. Spine 2000;25:2913–5.
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Technical Note
Atlantoaxial stabilization utilizing atlas translaminar fixation Ali A. Baaj a,b,⇑, Frank D. Vrionis b,1 a b
Department of Neurosurgery, College of Medicine, University of South Florida, 2A Columbia Drive, Tampa, Florida 33606, USA Department of Neuro-Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
a r t i c l e
i n f o
Article history: Received 28 March 2010 Accepted 4 April 2010 Keywords: Atlas Fusion Metastasis spine tumors
a b s t r a c t Atlantoaxial instability is a potentially devastating sequela of tumor invasion to the upper cervical spine. We aim to report an alternative technique for atlantoaxial stabilization. Stabilization is technically demanding due to limited bony elements and proximity of the regional neurovascular structures. While the C1 lateral masses are considered robust points of fixation, one or both of these structures may be destroyed by pathology. A 54-year-old female presented with a lytic, metastatic lesion to one of the C1 lateral masses, which precluded its use for fixation. We utilized the contralateral hemilamina of the atlas for screw fixation and devised a stable construct that provided immediate stability. Thus, atlas translaminar fixation is a feasible option when the lateral masses cannot be utilized. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Several pathological entities may lead to atlantoaxial instability, including trauma, tumors, and inflammatory conditions. Internal fixation in this region is technically challenging given the small working channels and the proximity of neurovascular structures to the bony elements. Clinically relevant techniques all utilize a combination of screws, hooks, rods or wires.1 The C1 lateral mass/C2 pars screw fixation construct, first reported by Goel and Laheri2 and later popularized by Harms and Melcher,3 is now considered one of the more robust constructs in this region. We present a patient in whom one of the C1 lateral masses was destroyed by an invasive tumor and, to rigidly fixate the atlantoaxial segment, the hemilamina was utilized instead as a fixation point. We believe this is a feasible option where pathology precludes using the C1 lateral mass as a fixation point. 2. Patient details 2.1. History and examination The patient was a 54-year-old female who was diagnosed with invasive ductal cell carcinoma of the left breast 9 years prior to this admission. She had undergone a left-sided lumpectomy followed by chemoradiation. She began to complain of new-onset, debilitating neck pain. She was neurologically intact with the exception of ⇑ Corresponding author. Tel.: +1 813 2590901; fax: +1 813 2590858. 1
E-mail address: [email protected] (A.A. Baaj). Frank D. Vrionis is a consultant for Stryker, Inc.
0967-5868/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2010.04.011
tenderness to palpation in the midline cervical spine. CT scan of the cervical spine revealed a lytic lesion involving the right C1 lateral mass and right hemilamina (Fig. 1). MRI was contraindicated as the patient had a metallic foreign body in her ear. A positron emission tomography (PET) scan demonstrated uptake in the upper cervical spine. Complete metastatic work-up, including neuroaxis imaging, revealed no other lesions.
2.2. Operative technique The patient was taken to the operating room for resection of a presumed metastatic lesion of the cervical spine and stabilization. She was placed in the prone position and 4.54 kg (10 lb) of cervical traction was applied. The atlantoaxial region was dissected and exposed through standard technique. C1 was clearly mobile with respect to C2. The lesion was visualized by the inferior aspect of the right C1 lateral mass region at the C1/C2 articulating joint. The lesion was removed in piece-meal fashion (subtotal resection) and pathology confirmed metastatic breast carcinoma. The third segment (V3) of the vertebral artery was visualized and uninjured. We proceeded to place the C1 lateral mass screw (LM) on the left using established techniques.5,6 Bicortical purchase was achieved. We also placed bilateral C2 pars (PS) and C3 lateral mass screws. As an additional point of fixation, we were able to drill, tap and place a 14 mm by 3.5 mm screw (Stryker; Kalamazoo, MI, USA) in the left hemilamina of the atlas. Bilateral 3.5 mm rods (left: C1 LM, C2 PS, C3 LM; right: C1 translaminar screw, C2 PS, C3 LM) were placed and a crosslink was applied. Allograft was placed over the construct after adequate decortication.
A.A. Baaj, F.D. Vrionis / Journal of Clinical Neuroscience 17 (2010) 1578–1580
Fig. 1. Preoperative axial CT scan of the cervical spine showing the lytic lesion involving the right C1 lateral mass and hemilamina.
2.3. Postoperative course The patient was extubated, placed in an Aspen collar and had no immediate postoperative deficits. Her pain had improved significantly. Postoperative plain radiographs showed adequate hardware placement and cervical alignment (Fig. 2). She was discharge to home 3 days after surgery. She re-presented 6 weeks later with dysphagia but no neurological deficits. Her CT scan (Fig. 3) demonstrated no hardware failure but did show tumor recurrence. She was scheduled for radiation therapy. 3. Discussion Metastatic disease to the spine continues to pose significant challenges to the treating spine surgeon. Despite advances in adju-
Fig. 2. Postoperative anteroposterior plain radiographs showing the C1–C3 construct with adequate hardware placement and cervical alignment.
1579
Fig. 3. Postoperative axial CT scan of the atlas showing the C1 hemilamina screw and no hardware failure.
vant therapy, surgical resection to either confirm suspected pathology, or, more often, to decompress the neural elements, remains the primary treatment modality in many cases. When tumor involves the craniocervical junction, it becomes paramount to not only to decompress, but also to provide immediate stability via internal fixation. Several fixation options have been described for atlantoaxial instability including the Brooks, Gallie, Sonntag wiring techniques, and more recently, the transarticular C1/C2 and the C1 lateral mass/C2 pars screw construct with rods and/or interspinous wiring.2–6 The latter construct (C1 LM/C2 PS) is the senior aurthor’s (FDV) preferred technique for atlantoaxial fixation. In this patient, the metastatic lesion had destroyed the inferior aspect of the right lateral mass of C1, which made placing a screw there impossible. There are several published reports describing fixation techniques when this situation is encountered. After resection of an aneurysmal bone cyst of the atlas, Wang et al.7 reconstructed the right lateral mass of C1 with a titanium mesh cage. The construct was augmented with occipital-C4 screw fixation. In a review article on spine reconstruction after tumor resection, Melcher and Harms8 present a similar case in which a destroyed C1 lateral mass was replaced with a titanium mesh cage. An occipital–cervical (O–C) instrumentation technique was similarly employed to complete the construct. Given the presumed osteopenic bone in our patient with metastatic breast cancer, and future irradiation, subsidence and/or dislodgement of a cage is a realistic possibility and could lead to serious neurovascular complications. We thus opted against placing a cage below the occipital condyle. Floyd and Grob9 previously described translaminar fixation of the atlas. In five patients with deficiency of the C1 posterior arch, the authors placed iliac crest graft posteriorly and fixated the grafts into each hemilamina of C1 with two screws (2.7 mm). The construct was augmented with C1/C2 transarticular screws and posterior wiring. In our patient, the right hemilamina of C1 was removed due to tumor invasion, but the left hemilamina was intact. Under direct visualization, we are able to drill, tap and place the translaminar screw. Equal, and symmetric, fixation would have likely provided
1580
A.A. Baaj, F.D. Vrionis / Journal of Clinical Neuroscience 17 (2010) 1578–1580
for a more biomechanically sound construct. This patient may develop muscular compensatory mechanisms away from the weak side (the right in this patient) which may lead to neck pain. Given the limited bony elements, however, and given the need for providing immediate stabilization, we determined that providing an additional point of fixation in the form of a translaminar atlas screw was warranted. Although extending the construct to the occiput would have been reasonable, we opted to spare the atlantooccipital motion segment. We appreciate the biomechanical significance of restoring the load-bearing property of the C1 lateral mass-occipital condyle complex, but we felt that a stable atlantoaxial construct with adequate occipitocervical alignment on preoperative films justified our decision not to fuse O–C1. In our experience, O–C constructs carry a lower fusion rate when compared to atlantoaxial techniques and also considerably limit patients’ range of motion. 4. Conclusions Atlantoaxial fixation is challenging. When pathology, such as tumor, destroys the bony elements in this region, the options for
fixation points become even more limited. The hemilamina of the atlas may by utilized as an additional point of fixation when clinically warranted. This could be part of an atlantoaxial or occipitocervical construct. Long-term efficacy and biomechanics of this technique need to be examined. References 1. Mummaneni PV, Haid RW. Atlantoaxial fixation: overview of all techniques. Neurol India 2005;53:408–15. 2. Goel A, Laheri V. Plate and screw fixation for atlanto-axial subluxation. Acta Neurochir (Wien) 1994;129:47–53. 3. Harms J, Melcher RP. Posterior C1–C2 fusion with polyaxial screw and rod fixation. Spine 2001;26:2467–71. 4. Brooks AL, Jenkins EB. Atlantoaxial arthrodesis by the wedge compression method. J Bone Joint Surg Am 1978;60A:279–84. 5. Dickman CA, Sonntag VK, Papadopoulos SM, et al. The interspinous method of posterior atlantoaxial arthrodesis. J Neurosurg 1991;74:190–8. 6. Gallie WE. Fractures and dislocations of cervical spine. Am J Surg 1939;46:495–9. 7. Wang VY, Deviren V, Ames CP. Reconstruction of C-1 lateral mass with titanium mesh cage after resection of an aneurysmal bone cyst of the atlas. J Neurosurg Spine 2009;10:117–21. 8. Melcher RP, Harms J. Biomechanics and materials of reconstruction after tumor resection in the spinal column. Orthop Clin North Am 2009;40:65–74. 9. Floyd T, Grob D. Translaminar screws in the atlas. Spine 2000;25:2913–5.