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Primary Lumbopelvic Fixation versus Revision Pelvic Fixation for Adult Spinal Deformity: A Case-Specific Approach
Perspectives Commentary on: Revision Extension to the Pelvis versus Primary Spinopelvic Instrumentation in Adult Deformity: Comparison of Clinical Outcomes and Complications by Fu et al. World Neurosurg 2014 http://dx.doi.org/10.1016/j.wneu.2013.02.059
Ziya L. Gokaslan, M.D. Professor, Department of Neurosurgery Johns Hopkins University
Primary Lumbopelvic Fixation versus Revision Pelvic Fixation for Adult Spinal Deformity: A Case-Specific Approach Paul E. Kaloostian and Ziya L. Gokaslan
A
dult spinal deformity is a complex pathologic condition that requires a critical evaluation of spinal curvature and meticulous calculation of the necessary corrective measurements. Adult spinal deformity stems from a variety of reasons, including spinal degenerative disease, trauma, tumor, and congenital instability. Adult patients with spinal deformity typically present with severe mechanical back pain and occasional radicular pain in the thoracolumbar dermatomes. Patients will notice progressively worsening posture, ranging from very mild C-shaped curves to severely deformed S-shaped curves with coronal and sagittal imbalance (8, 15, 20, 22).
The diagnosis of spinal deformity is made from the results of a careful history and physical examination, as well as a combination of imaging modalities. Anteroposterior and lateral standing scoliosis radiographs are obtained to calculate all the necessary measurements, including the Cobb angle. A computed tomography scan of the entire spine is obtained to assess bony anatomy at each level and degree of bone quality. Magnetic resonance imaging of the entire spine is obtained to evaluate for any neural element compression centrally or foraminally as well as to better assess degenerative disc disease at each level and presence of oncologic/infectious pathology that may contribute to the deformity. Bone scans may be obtained preoperatively to form a better idea of a patient’s bone density. Surgical management of adult spinal deformity will depend on the uniqueness of each patient’s presentation but generally involves multiple levels of pedicle screw instrumentation both
Key words Complications - Instrumentation - Pelvis - Revision - Spine deformity - Surgery -
WORLD NEUROSURGERY 00 (0): ---, MONTH 2014
above and below the designated apex of the curvature, with appropriate Smith-Petersen osteotomies contributing 6e10 degrees of added sagittal plane correction per level and pedicle subtraction osteotomies contributing 30 degrees of added sagittal plane correction per level. Generally, the calculation involves the sum total of the individually measured pelvic incidence plus lumbar lordosis plus thoracic kyphosis to be less than or equal to 45 degrees. The more lumbar lordosis created via the osteotomies will increase the lumbar lordosis, which decreases the overall score (8, 15, 20, 22). The lumbosacral junction has been well studied to be a site of extremely high mechanical demand, with a high range of reported pseudoarthrosis at that level resulting from the presence of a long fusion construct and spondylolisthesis (1, 2, 4, 16, 17, 21). In many previous studies, investigators also have shown that patients treated with long instrumentation constructs to the distal lumbar spine will eventually develop painful degeneration at the site inferior to the level of fusion (6, 7, 9, 13). Various surgical strategies have been implemented to augment strength at the lumbosacral junction, including the use of S2 pedicle screws, S1 foraminal hooks, and divergent sacral alar screws, transiliac screws, intrasacral rods, iliac rods, iliac screws, the Galveston technique, and iliosacral screws. Bridwell (5) noted in his series of patients undergoing revision spondylolisthesis that for high-grade dysplastic spondylolisthesis and low-grade adult isthmic spondylolisthesis, a combination of anterior column support and/or iliac screw fixation may help
Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland, USA To whom correspondence should be addressed: Paul E. Kaloostian, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.03.029
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
diminish the incidence of failure and revision surgery. Thus, at the author’s institution, supplementing thoracolumbar instrumentation in a separate surgery with anterior/lateral/posterior lumbar interbody grafting has been the mainstay of treatment with improved outcomes. A problem often encountered in primary adult deformity surgery is whether to extend the instrumentation as far inferiorly as the pelvis or instead terminate the construct at L5 or S1. This decision is often made less difficult with the presence of severe spondylolisthesis and severe disk degeneration at the lumbosacral junction or in cases that require laminectomy at L5-S1. However, in cases that involve minimal lumbosacral degenerative disk disease and minimal if any spondylolisthesis at the lumbosacral junction, this decision is made more difficult. In this issue of WORLD NEUROSURGERY, Fu et al. (10) performed a retrospective multicenter study of patients with adult deformity demonstrating that primary and revision extension to the pelvis have similar radiographic and clinical success in long-term followup. They identified that revision lumbopelvic surgery extending to the pelvis is not without complications, although the complication rate seems to be similar to a primary lumbopelvic operation. These data make one think hard about performing a primary lumbopelvic fixation in these patients with mild degenerative disease at the lumbosacral junction in the hope of long-term stabilization without a reoperation in the future. Biomechanically, a considerable advantage exists in extending the fusion construct to the pelvis. Long spinal fusions extending over the thoracolumbar junction will often require fixation to the pelvis to protect S1 screws against pullout, to correct pelvic obliquity that may be present, to resist such high forces placed upon the implants at every level, for sacroiliac dislocations, for revision spondylolisthesis surgery, and as a scaffold after tumor/trauma/infection surgery defects (3, 5, 11, 12, 18, 20). Lebwohl et al. (15) noted in their biomechanical study that the addition of sacral screws distal to S1 decreased strain on S1 screws and that the addition of iliac fixation was mechanically superior and necessary to avoid hardware failure. Tsuchiya et al. (22) describe no cases of screw failure in their series of 67 patients undergoing bilateral S1 and iliac screws for lumbosacral fusion. Thus, for patients with high-grade spondylolisthesis and long adult deformity fusions to the sacrum, an algorithm of bilateral S1 screws and iliac screws were effective in protecting the sacral screws from failure. Also, ending a long fusion in the sacrum without pelvic fixation has been noted to have a complication rate that is not
REFERENCES 1. Alegre GM, Gupta MC, Bay BK, Smith TS, Laubach JE: S1 screw bending moment with posterior spinal instrumentation across the lumbosacral junction after unilateral iliac crest harvest. Spine (Phila Pa 1976) 26:1950-1955, 2001. 2. Allen BL, Ferguson RL: The Galveston technique of pelvic fixation with L-rod instrumentation of the spine. Spine 9:388-394, 1984.
2
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insignificant. These include sacral fractures and a 25% pseudoarthrosis rate at L5-S1 (14, 19). Another factor that is critical to consider when evaluating pelvic instrumentation includes the quality of the patient’s bone. Patients with severe osteopenia as demonstrated by preoperative bone scans and dual-energy X-ray absorptiometry scans are at greater risk of screw pullout and pseudoarthrosis and subsequently revision pelvic extension. At the author’s institution, all patients who are scheduled for deformity surgery undergo strict preoperative preparation, including dual-energy X-ray absorptiometry scans, a consultation with an endocrinologist, measurement of vitamin D and calcium levels, measurement of estrogen and testosterone levels, as well as supplementation with calcium and vitamin D tablets. Thus, patients with moderate-to-severe osteopenia with minimal degenerative disease at lumbosacral junction may benefit from primary extension to the pelvis. Also, the surgeon must be aware of the patient’s pelvic anatomy and obliquity, as well as the presence of sacroiliac dislocations, that may predispose patients to accelerated degenerated disease and increase pseudoarthrosis. In these cases, extension to the pelvis is warranted on primary surgery. Disadvantages to the use of pelvic screws are not infrequent. Tsuchiya et al. (22) noted in their series of 67 patients undergoing bilateral S1 and iliac screws with 5-year follow-up that just over more than-third of the patients had their screws electively removed at the 2-year mark due to the degree of prominence. For patients who are thin, adolescent, and/or elderly, this factor must be taken into account preoperatively. Also, the degree of extra exposure and operative time required to place the pelvic screws and to contour the rods appropriately is not insignificant. The increased anesthesia time and blood loss increases the risk of surgery, especially in patients who are high surgical risks. Thus, adult deformity surgery is a complex specialty that requires a meticulous analysis of a wide variety of factors to ensure adequate patient outcome. The determination to extend long thoracolumbar constructs to the pelvis on a primary operation should be based on the anatomy of each patient’s particular curvature, patient bone density and quality, anatomy of the lumbosacral junction, and anatomy of the pelvis. With such high rates of complications in cases ending above the pelvis, and with clinical and radiographic outcomes similar between revision and primary pelvic operations, surgeons should have a low threshold for extension into the pelvis. Supplementation of posterior instrumentation with anterior column support via interbody grafts and appropriate preoperative preparation may play a role in decreasing risk of postoperative complications.
3. Alman BA, Kim HK: Pelvic obliquity after fusion of the spine in Duchenne muscular dystrophy. J Joint Bone Surg Br 81:821-824, 1999. 4. Bernhardt M, Swartz DE, Clothiaux PL, Crowell RR, White AA: Posterolateral lumbar and lumbosacral fusion with and without pedicle screw internal fixation. Clin Orthop Relat Res 284:109-115, 1992. 5. Bridwell KH: Utilizations of iliac screws and structural interbody grafting for revision
spondylolisthesis surgery. Spine (Phila Pa 1976) 30:588-596, 2005. 6. Cochran T, Irstam L, Nachemson A: Long-term anatomic and functional changes in patients with adolescent idiopathic scoliosis treated with Harrington rod fusion. Spine (Phila Pa 1976) 8: 576-584, 1983. 7. Connolly PJ, Von Schroeder HP, Johnson GE, Kostuik JP: Adolescent idiopathic scoliosis. Long term effect of instrumentation extending to the
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.03.029
PERSPECTIVES
lumbar spine. J Bone Joint Surg Am 77:1210-1216, 1995. 8. Cunningham BW, Lewis SJ, Long J, Dmitriev AE, Linville DA, Bridwell KH: Biomechanical evaluation of lumbosacral reconstruction techniques for spondylolisthesis: an in vitro porcine model. Spine (Phila Pa 1976) 27:2321-2327, 2002. 9. Eck KR, Bridwell KH, Ungacta FF, Riew KD, Lapp MA, Lenke LG, Baldus C, Blanke K: Complications and results of long adult deformity fusions down to L4, L5, and the sacrum. Spine (Phila Pa 1976) 26:E182-E192, 2001. 10. Fu KM, Smith JS, Burton DC, Kebaish KM, Shaffrey CI, Schwab F, Lafage V, Arlet V, Hostin R, Boachie O, Akbarnia B, Bess S; International Spine Study Group: Revision extension to the pelvis versus primary spinopelvic instrumentation in adult deformity: comparison of clinical outcomes and complications. World Neurosurg 2013 Feb 21 [Epub ahead of print]. 11. Gau YL, Lonstein JE, Winter RB, Koop S, Denis F: Luque-Galveston procedure for correction an stabilization of neuromuscular scoliosis and pelvic obliquity: a review of 68 patients. J Spinal Disord 4:399-410, 1991. 12. Gokaslan ZL, Romsdahl MM, Kroll SS, Walsh GL, Gillis TA, Wildrick DM, Leavens ME: Total sacrectomy and Galveston L-rod reconstruction for malignant neoplasms. Technical note. J Neurosurg 87:781-787, 1997.
13. Islam NC, Wood KB, Transfeldt EE, Winter RB, Denis F, Lonstein JE, Ogilvie JW: Extension of fusions to the pelvis in idiopathic scoliosis. Spine (Phila Pa 1976) 26:166-173, 2001.
19. Papadopoulos EC, Cammisa FP, Girardi FP: Sacral fractures complicating thoracolumbar fusion to the sacrum. Spine (Phila Pa 1976) 33:E699-E707, 2008.
14. Kebaish KM: Sacropelvic fixation: techniques and complication. Spine (Phila Pa 1976) 35:2245-2251, 2010.
20. Perra JH: Techniques of instrumentation in long fusions to the sacrum. Orthop Clin North Am 25: 287-299, 1994.
15. Lebwohl NH, Cunningham BW, Dmitriev A, Shimamoto N, Gooch L, Devlin V, Boachie-Adjei O, Wagner TA: Biomechanical comparison of lumbosacral fixation techniques in a calf spine model. Spine (Phila Pa 1976) 27:2312-2320, 2002.
21. Schwab FJ, Nazarian DG, Mahmud F, Michelsen CB: Effects of spinal instrumentation on fusion of the lumbosacral spine. Spine (Phila Pa 1976) 20:2023-2028, 1995.
16. Leong JC, Lu WW, Zheng Y, Zhu Q, Zhong S: Comparison of the strengths of lumbosacral fixation achieved with techniques using one and two triangulated sacral screws. Spine (Phila Pa 1976) 23:2289-2294, 1998. 17. Molinari RW, Bridwell KH, Lenke LG, Ungacta FF, Riew KD: Complications in the surgical treatment of pediatric-grade isthmic dysplastic spondylolisthesis. A comparison of three surgical approaches. Spine (Phila Pa 1976) 24:1701-1711, 1999. 18. Moshirfar A, Rand FF, Sponseller PD, Parazin SJ, Khanna AJ, Kebaish KM, Stinson JT, Riley LH: Pelvic fixation in spine surgery: historical overview, indications, biomechanical relevance and current techniques. J Bone Joint Surg Am 87: 89-106, 2005.
WORLD NEUROSURGERY 00 (0): ---, MONTH 2014
22. Tsuchiya K, Bridwell K, Kuklo T, Lenke L, Baldus C: Minimum 5-year analysis of L5-S1 fusion using sacropelvic fixation (bilateral S1 and iliac screws) for spinal deformity. Spine (Phila Pa 1976) 31:303-308, 2006.
Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.03.029 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
3
Ziya L. Gokaslan, M.D. Professor, Department of Neurosurgery Johns Hopkins University
Primary Lumbopelvic Fixation versus Revision Pelvic Fixation for Adult Spinal Deformity: A Case-Specific Approach Paul E. Kaloostian and Ziya L. Gokaslan
A
dult spinal deformity is a complex pathologic condition that requires a critical evaluation of spinal curvature and meticulous calculation of the necessary corrective measurements. Adult spinal deformity stems from a variety of reasons, including spinal degenerative disease, trauma, tumor, and congenital instability. Adult patients with spinal deformity typically present with severe mechanical back pain and occasional radicular pain in the thoracolumbar dermatomes. Patients will notice progressively worsening posture, ranging from very mild C-shaped curves to severely deformed S-shaped curves with coronal and sagittal imbalance (8, 15, 20, 22).
The diagnosis of spinal deformity is made from the results of a careful history and physical examination, as well as a combination of imaging modalities. Anteroposterior and lateral standing scoliosis radiographs are obtained to calculate all the necessary measurements, including the Cobb angle. A computed tomography scan of the entire spine is obtained to assess bony anatomy at each level and degree of bone quality. Magnetic resonance imaging of the entire spine is obtained to evaluate for any neural element compression centrally or foraminally as well as to better assess degenerative disc disease at each level and presence of oncologic/infectious pathology that may contribute to the deformity. Bone scans may be obtained preoperatively to form a better idea of a patient’s bone density. Surgical management of adult spinal deformity will depend on the uniqueness of each patient’s presentation but generally involves multiple levels of pedicle screw instrumentation both
Key words Complications - Instrumentation - Pelvis - Revision - Spine deformity - Surgery -
WORLD NEUROSURGERY 00 (0): ---, MONTH 2014
above and below the designated apex of the curvature, with appropriate Smith-Petersen osteotomies contributing 6e10 degrees of added sagittal plane correction per level and pedicle subtraction osteotomies contributing 30 degrees of added sagittal plane correction per level. Generally, the calculation involves the sum total of the individually measured pelvic incidence plus lumbar lordosis plus thoracic kyphosis to be less than or equal to 45 degrees. The more lumbar lordosis created via the osteotomies will increase the lumbar lordosis, which decreases the overall score (8, 15, 20, 22). The lumbosacral junction has been well studied to be a site of extremely high mechanical demand, with a high range of reported pseudoarthrosis at that level resulting from the presence of a long fusion construct and spondylolisthesis (1, 2, 4, 16, 17, 21). In many previous studies, investigators also have shown that patients treated with long instrumentation constructs to the distal lumbar spine will eventually develop painful degeneration at the site inferior to the level of fusion (6, 7, 9, 13). Various surgical strategies have been implemented to augment strength at the lumbosacral junction, including the use of S2 pedicle screws, S1 foraminal hooks, and divergent sacral alar screws, transiliac screws, intrasacral rods, iliac rods, iliac screws, the Galveston technique, and iliosacral screws. Bridwell (5) noted in his series of patients undergoing revision spondylolisthesis that for high-grade dysplastic spondylolisthesis and low-grade adult isthmic spondylolisthesis, a combination of anterior column support and/or iliac screw fixation may help
Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland, USA To whom correspondence should be addressed: Paul E. Kaloostian, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.03.029
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
diminish the incidence of failure and revision surgery. Thus, at the author’s institution, supplementing thoracolumbar instrumentation in a separate surgery with anterior/lateral/posterior lumbar interbody grafting has been the mainstay of treatment with improved outcomes. A problem often encountered in primary adult deformity surgery is whether to extend the instrumentation as far inferiorly as the pelvis or instead terminate the construct at L5 or S1. This decision is often made less difficult with the presence of severe spondylolisthesis and severe disk degeneration at the lumbosacral junction or in cases that require laminectomy at L5-S1. However, in cases that involve minimal lumbosacral degenerative disk disease and minimal if any spondylolisthesis at the lumbosacral junction, this decision is made more difficult. In this issue of WORLD NEUROSURGERY, Fu et al. (10) performed a retrospective multicenter study of patients with adult deformity demonstrating that primary and revision extension to the pelvis have similar radiographic and clinical success in long-term followup. They identified that revision lumbopelvic surgery extending to the pelvis is not without complications, although the complication rate seems to be similar to a primary lumbopelvic operation. These data make one think hard about performing a primary lumbopelvic fixation in these patients with mild degenerative disease at the lumbosacral junction in the hope of long-term stabilization without a reoperation in the future. Biomechanically, a considerable advantage exists in extending the fusion construct to the pelvis. Long spinal fusions extending over the thoracolumbar junction will often require fixation to the pelvis to protect S1 screws against pullout, to correct pelvic obliquity that may be present, to resist such high forces placed upon the implants at every level, for sacroiliac dislocations, for revision spondylolisthesis surgery, and as a scaffold after tumor/trauma/infection surgery defects (3, 5, 11, 12, 18, 20). Lebwohl et al. (15) noted in their biomechanical study that the addition of sacral screws distal to S1 decreased strain on S1 screws and that the addition of iliac fixation was mechanically superior and necessary to avoid hardware failure. Tsuchiya et al. (22) describe no cases of screw failure in their series of 67 patients undergoing bilateral S1 and iliac screws for lumbosacral fusion. Thus, for patients with high-grade spondylolisthesis and long adult deformity fusions to the sacrum, an algorithm of bilateral S1 screws and iliac screws were effective in protecting the sacral screws from failure. Also, ending a long fusion in the sacrum without pelvic fixation has been noted to have a complication rate that is not
REFERENCES 1. Alegre GM, Gupta MC, Bay BK, Smith TS, Laubach JE: S1 screw bending moment with posterior spinal instrumentation across the lumbosacral junction after unilateral iliac crest harvest. Spine (Phila Pa 1976) 26:1950-1955, 2001. 2. Allen BL, Ferguson RL: The Galveston technique of pelvic fixation with L-rod instrumentation of the spine. Spine 9:388-394, 1984.
2
www.SCIENCEDIRECT.com
insignificant. These include sacral fractures and a 25% pseudoarthrosis rate at L5-S1 (14, 19). Another factor that is critical to consider when evaluating pelvic instrumentation includes the quality of the patient’s bone. Patients with severe osteopenia as demonstrated by preoperative bone scans and dual-energy X-ray absorptiometry scans are at greater risk of screw pullout and pseudoarthrosis and subsequently revision pelvic extension. At the author’s institution, all patients who are scheduled for deformity surgery undergo strict preoperative preparation, including dual-energy X-ray absorptiometry scans, a consultation with an endocrinologist, measurement of vitamin D and calcium levels, measurement of estrogen and testosterone levels, as well as supplementation with calcium and vitamin D tablets. Thus, patients with moderate-to-severe osteopenia with minimal degenerative disease at lumbosacral junction may benefit from primary extension to the pelvis. Also, the surgeon must be aware of the patient’s pelvic anatomy and obliquity, as well as the presence of sacroiliac dislocations, that may predispose patients to accelerated degenerated disease and increase pseudoarthrosis. In these cases, extension to the pelvis is warranted on primary surgery. Disadvantages to the use of pelvic screws are not infrequent. Tsuchiya et al. (22) noted in their series of 67 patients undergoing bilateral S1 and iliac screws with 5-year follow-up that just over more than-third of the patients had their screws electively removed at the 2-year mark due to the degree of prominence. For patients who are thin, adolescent, and/or elderly, this factor must be taken into account preoperatively. Also, the degree of extra exposure and operative time required to place the pelvic screws and to contour the rods appropriately is not insignificant. The increased anesthesia time and blood loss increases the risk of surgery, especially in patients who are high surgical risks. Thus, adult deformity surgery is a complex specialty that requires a meticulous analysis of a wide variety of factors to ensure adequate patient outcome. The determination to extend long thoracolumbar constructs to the pelvis on a primary operation should be based on the anatomy of each patient’s particular curvature, patient bone density and quality, anatomy of the lumbosacral junction, and anatomy of the pelvis. With such high rates of complications in cases ending above the pelvis, and with clinical and radiographic outcomes similar between revision and primary pelvic operations, surgeons should have a low threshold for extension into the pelvis. Supplementation of posterior instrumentation with anterior column support via interbody grafts and appropriate preoperative preparation may play a role in decreasing risk of postoperative complications.
3. Alman BA, Kim HK: Pelvic obliquity after fusion of the spine in Duchenne muscular dystrophy. J Joint Bone Surg Br 81:821-824, 1999. 4. Bernhardt M, Swartz DE, Clothiaux PL, Crowell RR, White AA: Posterolateral lumbar and lumbosacral fusion with and without pedicle screw internal fixation. Clin Orthop Relat Res 284:109-115, 1992. 5. Bridwell KH: Utilizations of iliac screws and structural interbody grafting for revision
spondylolisthesis surgery. Spine (Phila Pa 1976) 30:588-596, 2005. 6. Cochran T, Irstam L, Nachemson A: Long-term anatomic and functional changes in patients with adolescent idiopathic scoliosis treated with Harrington rod fusion. Spine (Phila Pa 1976) 8: 576-584, 1983. 7. Connolly PJ, Von Schroeder HP, Johnson GE, Kostuik JP: Adolescent idiopathic scoliosis. Long term effect of instrumentation extending to the
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.03.029
PERSPECTIVES
lumbar spine. J Bone Joint Surg Am 77:1210-1216, 1995. 8. Cunningham BW, Lewis SJ, Long J, Dmitriev AE, Linville DA, Bridwell KH: Biomechanical evaluation of lumbosacral reconstruction techniques for spondylolisthesis: an in vitro porcine model. Spine (Phila Pa 1976) 27:2321-2327, 2002. 9. Eck KR, Bridwell KH, Ungacta FF, Riew KD, Lapp MA, Lenke LG, Baldus C, Blanke K: Complications and results of long adult deformity fusions down to L4, L5, and the sacrum. Spine (Phila Pa 1976) 26:E182-E192, 2001. 10. Fu KM, Smith JS, Burton DC, Kebaish KM, Shaffrey CI, Schwab F, Lafage V, Arlet V, Hostin R, Boachie O, Akbarnia B, Bess S; International Spine Study Group: Revision extension to the pelvis versus primary spinopelvic instrumentation in adult deformity: comparison of clinical outcomes and complications. World Neurosurg 2013 Feb 21 [Epub ahead of print]. 11. Gau YL, Lonstein JE, Winter RB, Koop S, Denis F: Luque-Galveston procedure for correction an stabilization of neuromuscular scoliosis and pelvic obliquity: a review of 68 patients. J Spinal Disord 4:399-410, 1991. 12. Gokaslan ZL, Romsdahl MM, Kroll SS, Walsh GL, Gillis TA, Wildrick DM, Leavens ME: Total sacrectomy and Galveston L-rod reconstruction for malignant neoplasms. Technical note. J Neurosurg 87:781-787, 1997.
13. Islam NC, Wood KB, Transfeldt EE, Winter RB, Denis F, Lonstein JE, Ogilvie JW: Extension of fusions to the pelvis in idiopathic scoliosis. Spine (Phila Pa 1976) 26:166-173, 2001.
19. Papadopoulos EC, Cammisa FP, Girardi FP: Sacral fractures complicating thoracolumbar fusion to the sacrum. Spine (Phila Pa 1976) 33:E699-E707, 2008.
14. Kebaish KM: Sacropelvic fixation: techniques and complication. Spine (Phila Pa 1976) 35:2245-2251, 2010.
20. Perra JH: Techniques of instrumentation in long fusions to the sacrum. Orthop Clin North Am 25: 287-299, 1994.
15. Lebwohl NH, Cunningham BW, Dmitriev A, Shimamoto N, Gooch L, Devlin V, Boachie-Adjei O, Wagner TA: Biomechanical comparison of lumbosacral fixation techniques in a calf spine model. Spine (Phila Pa 1976) 27:2312-2320, 2002.
21. Schwab FJ, Nazarian DG, Mahmud F, Michelsen CB: Effects of spinal instrumentation on fusion of the lumbosacral spine. Spine (Phila Pa 1976) 20:2023-2028, 1995.
16. Leong JC, Lu WW, Zheng Y, Zhu Q, Zhong S: Comparison of the strengths of lumbosacral fixation achieved with techniques using one and two triangulated sacral screws. Spine (Phila Pa 1976) 23:2289-2294, 1998. 17. Molinari RW, Bridwell KH, Lenke LG, Ungacta FF, Riew KD: Complications in the surgical treatment of pediatric-grade isthmic dysplastic spondylolisthesis. A comparison of three surgical approaches. Spine (Phila Pa 1976) 24:1701-1711, 1999. 18. Moshirfar A, Rand FF, Sponseller PD, Parazin SJ, Khanna AJ, Kebaish KM, Stinson JT, Riley LH: Pelvic fixation in spine surgery: historical overview, indications, biomechanical relevance and current techniques. J Bone Joint Surg Am 87: 89-106, 2005.
WORLD NEUROSURGERY 00 (0): ---, MONTH 2014
22. Tsuchiya K, Bridwell K, Kuklo T, Lenke L, Baldus C: Minimum 5-year analysis of L5-S1 fusion using sacropelvic fixation (bilateral S1 and iliac screws) for spinal deformity. Spine (Phila Pa 1976) 31:303-308, 2006.
Citation: World Neurosurg. (2014). http://dx.doi.org/10.1016/j.wneu.2013.03.029 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
3