Surgical treatment of scoliosis: a review of techniques currently applied
© Maruyama and Takeshita; licensee BioMed Central Ltd. 2008
Received: 14 January 2008
Accepted: 18 April 2008
Published: 18 April 2008
In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that:
1) Curves larger than 50 degrees progress even after skeletal maturity.
2) Curves of greater magnitude cause loss of pulmonary function, and much larger curves cause respiratory failure.
3) Larger the curve progress, more difficult to treat with surgery.
Posterior fusion with instrumentation has been a standard of the surgical treatment for scoliosis. In modern instrumentation systems, more anchors are used to connect the rod and the spine, resulting in better correction and less frequent implant failures. Segmental pedicle screw constructs or hybrid constructs using pedicle screws, hooks, and wires are the trend of today.
Anterior instrumentation surgery had been a choice of treatment for the thoracolumbar and lumbar scoliosis because better correction can be obtained with shorter fusion levels. Recently, superiority of anterior surgery for the thoracolumbar and lumbar scoliosis has been lost. Initial enthusiasm for anterior instrumentation for the thoracic curve using video assisted thoracoscopic surgery technique has faded out.
Various attempts are being made with use of fusionless surgery. To control growth, epiphysiodesis on the convex side of the deformity with or without instrumentation is a technique to provide gradual progressive correction and to arrest the deterioration of the curves. To avoid fusion for skeletally immature children with spinal cord injury or myelodysplasia, vertebral wedge ostetomies are performed for the treatment of progressive paralytic scoliosis. For right thoracic curve with idiopathic scoliosis, multiple vertebral wedge osteotomies without fusion are performed. To provide correction and maintain it during the growing years while allowing spinal growth for early onset scoliosis, technique of instrumentation without fusion or with limited fusion using dual rod instrumentation has been developed. To increase the volume of the thorax in thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis, vertical expandable prosthetic titanium ribs has been developed.
Considering that not all the scoliosis patients can be treated successfully with conservative treatment and severe and/or progressive scoliosis often need surgery, even the specialists of conservative treatment should have knowledge about surgical treatment. In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Because relatively little data are obtained regarding outcomes in the long-term or clinical outcomes such as patients' satisfaction, the particular techniques will be discussed mainly based on the radiological outcomes in the middle-term, sometimes short-term follow-up.
Indication of surgery
Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that:
1) Curves larger than 50 degrees progress even after skeletal maturity. Thoracic curves with magnitude between 50 and 75 degrees at skeletal maturity (Risser IV or V) progressed of an average of 29.4 degrees over the 40.5 years follow-up period . Curves larger than 55 degrees at skeletal maturity (partial or total fusion of the completed iliac apophyses) progressed of more than 0.5 degrees per year . Thoracic curves with an average Cobb angle of 60.5 dgrees progressed to 84.5 degrees over the 50 years follow-up period .
2) Curves of greater magnitude cause loss of pulmonary function, and much larger curves cause respiratory failure. In patients with curves between 60 and 100 degrees, total lung capacity was 68% of predicted normal values . Nearly half of the patients with thoracic curve larger than 80° degrees had shortness of breath at the average age of 42 years . Vital capacity below 45% predicted and a Cobb angle greater than 110 degrees were risk factors to develop respiratory failure and earlier death .
3) Larger the curve progress, more difficult to treat with surgery: more surgical anchors may be necessary, longer operation time, more blood loss, higher surgical complication rate may be expected.
Sometimes patient's motivation to straighten her/his spine by surgery should be respected, especially for the patient with gray zone curve, Cobb angle of 40 to 45 degrees.
Surgical treatment for scoliosis can be divided into fusion surgery and fusionless surgery.
A segmental pedicle screw concept was first introduced by Suk . He reported that the idiopathic thoracic curves of 51 degrees in average were corrected to 16 degrees (69% correction) with a minimum 5-year follow-up. Although 1.5% of the screws inserted in the thoracic level were malpositioned, they did not cause neurologic complications or adversely affect the long-term results. Asher et al.  reported on 63% correction with a minimum 5-year follow-up using hybrid constructs with hooks, apical sublaminar wires, and pedicle screws. In 2005, Cheng et al.  compared apical sublaminar wires with pedicle screws. No difference was found regarding initial correction (67.4% vs. 68.1%), loss of correction (4.6% vs. 5.1%), operating time (350 minutes vs. 357 minutes), satisfaction of the patients, but intraoperative blood loss was more with wires (1791 ml vs. 824 ml) and instrumentation cost was higher with screws (8341 USD vs. 13462 USD). Another concern with segmental pedicle screw constructs is that vigorous correction of a major curve is an overcorrection relative to the flexibility of the upper compensatory curve . Generally, an extent of fusion level is determined with the flexibility of the curves demonstrated on the radiographs taken in supine side bending, fulcrum side bending, traction, or push-prone position [14–16]. With segmental pedicle screw technique, to avoid the postoperative shoulder imbalance, frequently fusion has to be extended to the upper thoracic vertebrae, which is not included in the fusion with other techniques.
Various attempts are being made with use of fusionless surgery to control growth, to avoid fusion, to delay the timing of the definitive fusion surgery, or to increase the volume of the thorax.
To control growth
Epiphysiodesis on the convex side of the deformity with or without instrumentation is a technique to provide gradual progressive correction and to arrest the deterioration of the curves. Marks et al.  found anterior and posterior growth arrest alone not effective to prevent progression of deformity in infantile scoliosis. To the contrary, Betz et al.  showed that stapling the anterior vertebral spinal growth plates could control growth of the curve with adolescent idiopathic scoliosis. By using newly designed biocompatible shape memory metal alloy staples, 6 of 10 patients with average curve magnitude of 35 degrees were stabilized during more than 1-year follow-up period. To avoid the overtreatment for relatively small, non-progressive curve with this technique, definite and solid criteria for hallmarking a curve as progressive should be established first.
To avoid fusion
By fusion surgery, segmental motion of the vertebral column is eliminated. To avoid fusion for patients with paralysis, for whom maintaining spinal flexibility and mobility is more desirable, fusionless, vertebral wedge ostetomies are developed for the treatment of progressive paralytic scoliosis of skeletally immature children with spinal cord injury or myelodysplasia . A specially designed implant system is used to assist with correction and maintenance of alignment. Twelve weeks following the initial surgery, a second surgery is necessary to remove parts of the implants. This technique may be used for idiopathic scoliosis in future.
To delay the timing of fusion
Fusion surgery in very young age results in the short trunk relative to the extremities. It also affects the development of the lung. To provide correction and maintain it during the growing years while allowing spinal growth for early onset scoliosis, technique of instrumentation without fusion or with limited fusion using Harrington rod, Cotrel-Dubousset rod, or Luque rod had been developed [27, 28]. Recently, Akbarnia et al.  developed the technique using Isola dual rod instrumentation. Upper and lower foundations are made bilaterally using hooks or pedicle screws as anchoring devices. Each foundation is connected to a rod, and the rods are connected by a tandem connector, which is placed at the thoracolumbar junction on each side. Lengthening is performed usually every 6 months by distraction inside the tandem connector or between the rod and the tandem connector. Once maximum spinal growth is accomplished, definitive final arthrodesis with instrumentation is performed. Between 1993 and 2001, 23 patients with various etiologies underwent this treatment at an average age of 5.4 years. The averaged curve magnitude was 82 degrees before surgery, 38 degrees after the initial surgery, and 36 degrees after 6.6 times of lengthening procedures. The length of thoracic and lumbar spine increased by 5 cm at the initial surgery and 4.7 cm in addition during the lengthening period.
To increase the volume of the thorax
To treat thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis, vertical expandable prosthetic titanium ribs (VEPTR) has been developed . After opening-wedge thoracostomy, the acute correction is stabilized by the device. The device is extended from the cephalad rib to the caudal rib, to the lumbar spine, or to the posterior iliac crest. Following the initial implantation, the devices are expanded at scheduled intervals of four to six months. Twenty-seven patients underwent surgery at the average age of 3.2 years and were followed-up for 5.7 years. Vital capacity significantly increased; moreover, scoliosis deformity was indirectly corrected from 74 to 49 degrees at the last follow-up.
We described the indication of surgical treatment for scoliosis, results of the innovative surgical techniques, in terms of, posterior fusion with instrumentation, anterior fusion with instrumentation, and various kinds of fusionless surgery.
We would like to thank Dr. Tomasz Kotwicki for approval to use radiographs of his patient.
- Weinstein SL, Ponseti IV: Curve progression in idiopathic scoliosis. J Bone Joint Surg Am. 1983, 65: 447-455.PubMedGoogle Scholar
- Edgar M: The natural history of unfused scoliosis. Orthopedics. 1987, 10 (6): 931-939.PubMedGoogle Scholar
- Weinstein SL, Dolan LA, Spratt KF, Peterson KK, Spoonamore MJ, Ponseti IV: Health and function of patients with untreated idiopathic scoliosis. JAMA. 2003, 289: 559-567. 10.1001/jama.289.5.559.View ArticlePubMedGoogle Scholar
- Bjure J, Grimby G, Kasalicky J, Lindh M, Nachemson A: Respiratory impairment and airway closure in patients with untreated idiopathic scoliosis. Thorax. 1970, 25: 451-456.View ArticlePubMedPubMed CentralGoogle Scholar
- Collis DK, Ponseti IV: Long-term follow-up of patients with idiopathic scoliosis not treated surgically. J Bone Joint Surg Am. 1969, 51: 425-445.PubMedGoogle Scholar
- Pehrsson K, Bake B, Larsson S, Nachemson A: Lung function in adult idiopathic scoliosis: a 20 year follow up. Thorax. 1991, 46: 474-478.View ArticlePubMedPubMed CentralGoogle Scholar
- Harington PR: Treatment of scoliosis. Correction and internal fixation by spine instrumentation. J Bone Joint Surg Am. 1962, 44: 591-610.Google Scholar
- Cotrel Y, Dubousset J, Guillaumat M: New universal instrumentation in spinal surgery. Clin Orthop. 1988, 227: 10-23.PubMedGoogle Scholar
- Shah SA: Derotation of the spine. Neurosurg Clin N Am. 2007, 18: 339-45. 10.1016/j.nec.2007.02.003.View ArticlePubMedGoogle Scholar
- Suk SI, Lee SM, Chung ER, Kim JH, Kim SS: Selective thoracic fusion with segmental pedicle screw fixation in the treatment of thoracic idiopathic scoliosis: more than 5-year follow-up. Spine. 2005, 30: 1602-1609. 10.1097/01.brs.0000169452.50705.61.View ArticlePubMedGoogle Scholar
- Asher MA, Lai SM, Burton D, Manna B, Cooper A: Safety and efficacy of Isola instrumentation and arthrodesis for adolescent idiopathic scoliosis: two- to 12-year follow-up. Spine. 2004, 29: 2013-2023. 10.1097/01.brs.0000138275.49220.81.View ArticlePubMedGoogle Scholar
- Cheng I, Kim YJ, Gupta MC, Bridwell KH, Hurford RK, Lee SS, Theerajunyaporn T, Lenke LG: Apical sublaminar wires versus pedicle screws-which provides better results for surgical correction of adolescent idiopathic scoliosis?. Spine. 2005, 30: 2104-2112. 10.1097/01.brs.0000179261.70845.b7.View ArticlePubMedGoogle Scholar
- Winter RB, Lonstein JE, Denis F: How much correction is enough?. Spine. 2007, 32: 2641-2643.View ArticlePubMedGoogle Scholar
- Vaughan JJ, Winter RB, Lonstein LE: Comparison of the use of spine bending and traction radiographs in the selection of the fusion area in adolescent idiopathic scoliosis. Spine. 1996, 21: 2469-2473. 10.1097/00007632-199611010-00012.View ArticlePubMedGoogle Scholar
- Cheung KMC, Luk KDK: Prediction of correction of scoliosis with use of the fulcrum bendingradiograph. J Bone Joint Surg Am. 1997, 79: 1144-1150.PubMedGoogle Scholar
- Vedantam R, Lenke LG, Bridwell KH, Linville DL: Comparison of push-prone and lateral-bending radiographs for predicting postoperative coronal alignment in thoracolumbar scoliotic curves. Spine. 2000, 25: 76-81. 10.1097/00007632-200001010-00014.View ArticlePubMedGoogle Scholar
- Picetti GD, Pang D, Bueff HU: Thoracoscopic techniques for the treatment of scoliosis: early results in procedure development. Neurosurgery. 2002, 51: 978-984. 10.1097/00006123-200210000-00023.PubMedGoogle Scholar
- Sucato DJ, Kassab F, Dempsey M: Analysis of screw placement relative to the aorta and spinal canal following anterior instrumentation for thoracic idiopathic scoliosis. Spine. 2004, 29: 554-559. 10.1097/01.BRS.0000106495.91477.92.View ArticlePubMedGoogle Scholar
- Maruyama T, Takeshita K, Nakamura K, Kitagawa T: Spatial relations between the vertebral body and the thoracic aorta in adolescent idiopathic scoliosis. Spine. 2004, 29: 2067-2069. 10.1097/01.brs.0000138409.14577.f0.View ArticlePubMedGoogle Scholar
- Kim YJ, Lenke LG, Bridwell KH, Kim KL, Steger-May K: Pulmonary function in adolescent idiopathic scoliosis relative to the surgical procedure. J Bone Joint Surg Am. 2005, 87: 1534-1541. 10.2106/JBJS.C.00978.View ArticlePubMedGoogle Scholar
- Potter BK, Kuklo TR, Lenke LG: Radiographic outcomes of anterior spinal fusion versus posterior spinal fusion with thoracic pedicle screws for treatment of Lenke type I adolescent idiopathic scoliosis curves. Spine. 2005, 30: 1859-1866. 10.1097/01.brs.0000174118.72916.96.View ArticlePubMedGoogle Scholar
- Hee HT, Yu ZR, Wong HK: Comparison of segmental pedicle screw instrumentation versus anterior instrumentation in adolescent idiopathic thoracolumbar and lumbar spine. Spine. 2007, 32: 1533-1542. 10.1097/BRS.0b013e318067dc3d.View ArticlePubMedGoogle Scholar
- Marks DS, Iqbal MJ, Thompson AG, Piggott H: Convex spinal epiphysiodesis in the management of progressive infantile idiopathic scoliosis. Spine. 1996, 21: 1884-1888. 10.1097/00007632-199608150-00010.View ArticlePubMedGoogle Scholar
- Betz RR, Kim J, D'Andrea LP, Mulcahey MJ, Balsara RK, Clements DH: An innovative technique of vertebral body stapling for the treatment of patients with adolescent idiopathic scoliosis: A feasibility, safety, and utility study. Spine. 2003, 28: S255-265. 10.1097/01.BRS.0000092484.31316.32.View ArticlePubMedGoogle Scholar
- Guille JT, Betz RR, Balsara RK, Mulcahey MJ, D'Andrea LP: Clements DH: The feasibility, safety, and utility of vertebral wedge osteotomies for the fusionless treatment of paralytic scoliosis. Spine. 2003, 28: S266-S274. 10.1097/01.BRS.0000092485.40061.ED.View ArticlePubMedGoogle Scholar
- Maruyama T, Kitagawa T, Takeshita K, Seichi A, Kojima T, Nakamura K, Kurokawa T: Fusionless surgery for scoliosis: 2–17 year radiographic and clinical follow-up. Spine. 2006, 31: 2310-2315. 10.1097/01.brs.0000238971.05671.d5.View ArticlePubMedGoogle Scholar
- Moe JH, Kharrat K, Winter RB, Cummine JL: Harington instrumentation without fusion plus external orthotic support for the treatment of difficult curvature problems in young children. Clin Orthop. 1984, 185: 35-45.PubMedGoogle Scholar
- Grivas TB, Webb JK, Burwell RG: The effects of epiphysiodesis and rodding for early onset scoliosis. J Bone Joint Surg Br. 1991, 32-33. Suppl 1Google Scholar
- Akbarnia BA, Marks DS, Boachie-Adjei O, Thompson AG, Asher MA: Dual growing rod technique for the treatment of progressive early-onset scoliosis. Spine. 2005, 30: 546-557. 10.1097/01.brs.0000175190.08134.73.View ArticleGoogle Scholar
- Campbell RM, Smith MD, Mayes TC, Mangos JA, Willey-Courand DB, Kose N, Pinero RF, Alder ME, Duong HL, Surber JL: The effect of opening wedge thoracostomy on thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis. J Bone Joint Surg Am. 2004, 86: 1659-1674.PubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.