More adults are suffering from adult idiopathic scoliosis and seeking treatment for their spinal deformities. Adult idiopathic scoliosis can lead to painful spinal osteoarthritis, progressive deformity, spinal stenosis with radiculopathy, muscle fatigue from coronal and sagittal plane imbalance, and psychological effects with a visible deformity. Primary treatment of such conditions is conservative; however, some patients are resistant to conservative treatment or are not candidates for it, and they require surgery. Back pain is likely the most common indication for surgical treatment of scoliosis in adult patients. Pedicle screws offer 3-column purchase and a longer arm compared with hook placement on the lamina. This study is a retrospective analysis of a consecutive series of patients with adult idiopathic scoliosis who were treated with pedicle screw placement. Significant back pain relief and satisfaction can be achieved and maintained over the long term. Restoration of coronal and sagittal balance, or improvement thereof, was achieved in all patients with balance problems. This study clarified several important characteristics of adult scoliosis, and we believe that useful conclusions can be drawn regarding its surgical indications and strategies: (1) pedicle screw construct can gain effective results for treatment of adult idiopathic scoliosis due to its perceived superior power of correction; (2) younger patients present for surgery for different reasons than older patients (progressive deformity or pain); and (3) pain improvement is a more reliable outcome in older patients than younger patients, although younger patients rarely have severe pain symptoms.
The natural course of adult idiopathic scoliosis is not static. It is reported that more adults are suffering from scoliosis and seeking treatment for their spinal deformities.1,2 As a patient ages, a deformed spinal column may suffer from aggravation of curves, causing kyphosis, decompensation, and spondylotic changes. These pathologic changes may cause back pain, radiculopathy, cosmetic and psychological problems, and cardiopulmonary compromise, possibly leading to higher mortality.3-5 Approximate 1,500,000 adults in China have curves >30°.6 Curvature progression averaging 1° per year >60° can be predicted in patients with thoracic curves and >40° lumbar curves.
Primary treatment of such conditions is conservative7,8; however, some patients are resistant to conservative treatment or are not candidates for it, and they require surgery. In general, surgical treatment of adult idiopathic scoliosis carries a higher risk than that of its adolescent counterpart because of increased rigidity of deformity, frequent association of kyphotic deformity, decreased bone strength, and cardiopulmonary compromise. The absolute amount of correction is not as critical as achieving a stable, well-balanced, and pain-free spine. Most studies reported a reduction from 60% to 95% in the severity of back pain and a correction of deformity from 30% to 50%.9-11
The present study is a retrospective analysis of a consecutive series of patients with adult idiopathic scoliosis who were treated with pedicle screw placement. Previous reports on the results of segmental types of posterior instrumentation surgery for adult scoliosis had limitations.11-13 Before 2000, patients with adult idiopathic scoliosis were treated with a hybrid construct or universal system with a segmental collar button intraspinous wire construct. It is believed that pedicle screw instrumentation achieves true 3-column fixation and enhances mechanical control of instrumented vertebral segments compared to a hook-and-wire construct. Pedicle screw constructs have demonstrated stabilization in the lumbar spine and thoracic deformity correction in adolescent idiopathic scoliosis compared to traditional hook-based constructs. This article describes curve correction and clinical results after surgical procedures in adult idiopathic scoliosis patients treated with pedicle screw placement.
Materials and Methods
The medical records and radiographs of patients with adult idiopathic scoliosis who had been followed up for at least 2 years were retrospectively reviewed. The patients were adolescents when diagnosed and older than 20 years at the time of surgery. Surgery was performed using pedicle screw placement (Medtronic Sofamor Danek, Memphis, Tennessee) and the Moss Miami spine system (DePuy Spine, Inc, Raynham, Massachusetts) without preceding spinal surgery.
The indications for surgical treatment included significant progression curve, back pain or back pain with radiculopathy uncontrollable by conservative methods, trunk imbalance in the sagittal or frontal plane, and respiratory compromise related to the chest deformity.1 A plumbline shift of the coronal plane >2.0 cm is defined as frontal imbalance. A plumbline shift of the sagittal plane >2.5 cm is defined as sagittal imbalance.14 Duration of back pain was defined as constant thoracic/thoracolumbar/lumbar pain that had lasted >1 year.
All patients underwent posterior correction and spinal fusion using pedicle screw placement. Three patients had anterior release and interbody bone grafting in the rigid area by an anterior approach before posterior instrumentation in the same anesthesia session. Lumbar lordosis disappeared in 3 patients of this group: 1 patients lumbar lordosis was 5°, one patients was 0°, and 1 patients was 3°. The ages of these patients were 29, 43, and 45 years, respectively. All the additional patients underwent posterior surgery alone. The caudal extent of spinal fusion was determined according to frontal and sagittal curvatures, flexibility of lumbar segments, and extent of disk degeneration. The spine was evaluated by magnetic resonance imaging (MRI) and/or myelography computed tomography (CT) to assess disk degeneration and determine whether the segment in question should be included in the fusion. Facet blocks as well as nerve root blocks were used to pinpoint the source of the patients pain in certain situations.
Different surgical techniques of correction were used for different deformities. The rod rotation maneuver was used in 34 patients.15 This procedure was performed either along the whole instrumented area or selectively in the thoracic/lumbar curve. Once the pedicle screws and hooks were placed, the rod on the convex side was inserted in situ. It was then rotated 90° to the convex side to convert the scoliosis into lordosis. Compression forces were applied to each lumbar segment to obtain further correction and lordosis. In 2 patients with fairly rigid thoracic curve, preoperative preparation by halo-pelvic traction for 2 weeks was followed by the so-called 3-rod technique.15 In 3 additional patients with a relatively flexible thoracic curve accompanying hyperkyphotic segments, a thoracic convex-side rod was instrumented first in a step-by-step manner to correct the frontal curve and hyperkyphosis at the same time by segmental compression, followed by a stabilizing concave-side rod. The correction obtained was confirmed intraoperatively using a intensified radiograph image. In practice, >1 technique was required in some patients. Selective correction of a high thoracic curve was performed in 3 patients by adding a separate short convex rod to the high thoracic part.16 Laminectomy was performed in 2 patients with radiculopathy or lumbar stenosis. Posterior spinal fusion was accomplished with autologous iliac bone graft added to the local bone chips in all patients. Intraoperative blood salvage techniques, including hypotensive anesthesia and cell saver, were used. Intraoperative somatosensory-evoked potential monitoring was performed routinely during the procedures.
Potential complications were recorded, such as deep infection, pneumonia, cardiovascular sequelae, implant failure or pullout, pulmonary embolus, neurologic deficit, paralysis, death, prolonged gastrointestinal dysfunction, urinary tract infection, venous catheter infection, and superficial wound infection.
All the patients were followed up at 6 months, 1 year, and 2 years postoperatively, then every 1 to 2 years thereafter. Routine examinations included inquiry into back pain, other symptoms, and activities of daily living, as well as general and local physical examinations and standing anteroposterior (AP) and lateral radiographs. Three-level verbal description scales were used to evaluate the average intensity of patients back pain during the previous 3 months17: no or rare pain, mild or occasional low-grade pain not usually requiring specific treatment, or moderate or severe pain requiring continuous treatment. Radiographic measurements were performed for Cobb angle of curves in the frontal plane, kyphosis between T3 and T12, lordosis between L1 and L5, and the frontal and sagittal balance of C7 in relation to S1 using the plumbline projected on radiograph.
Differences between various age groups were analyzed using one-way analysis of variance (ANOVA). When ANOVA found a significant difference among the groups, all pairwise multiple comparison procedures (Tukey test) were further performed to test every combination of 2 groups. Differences with a P<.05 were considered statistically significant.
Between 2003 and 2007, a total of 41 adult patients with idiopathic scoliosis underwent surgical treatment at our institution. Average patient age at the time of surgery was 46.3 years (range, 20-59 years). One patient died of an unrelated cause 1 year postoperatively, and 1 patient was followed up for only 1 year postoperatively and could not be located thereafter. Two patients were excluded from the analysis, leaving 39 patients (11 men and 28 women) for the current study. Follow-up ranged from 2 to 6 years (mean, 3.6 years). At the time of surgery, 7 patients were in their twenties, 9 were in their thirties, 14 were in their forties, and 9 were in their fifties. There were 12 cases of thoracic curves without structural lumbar component, 21 cases of combined thoracic and lumbar curves, and 6 cases of single thoracolumbar or lumbar curves. Of 33 patients with thoracic curves, 7 had a structural high thoracic curve. The distribution of different curve patterns according to the age of patients is shown in Table 1.
Back pain was rarely seen in patients younger than 30 years, where cosmetic concerns predominated. However, back pain often was the major reason for surgery in patients older than 40 years. Back pain was the chief reason for surgery in 16 of 23 patients older than 40 years. In 2 patients older than 30 years, dyspnea on effort or dyspnea related to back pain or heaviness of the back were a reason for surgery; other etiologies such as asthma, emphysema, and abnormal chest radiographs were excluded.
Back pain or back pain with radiculopathy in these adult idiopathic scoliosis patients originated from lumbar, cervical, thoracolumbar, or thoracic regions. As shown in Table 2, many patients younger than 40 years had no or rare back pain preoperatively, whereas older patients had severe back pain preoperatively. At final follow-up, surgery had decreased the prevalence of back pain requiring analgesic treatment from 21% to 5%, and increased the number of patients with no or rare back pain from 17% to 21%. Patients younger than 40 years did not gain a reliable decrease in the prevalence of back pain. Radicular pain disappeared in 5 patients postoperatively.
No patients had restriction in their activities of daily living at final follow-up. All the patients were physically independent in activities of daily living. Two patients who had dyspnea preoperatively experienced subjective amelioration of respiratory symptoms by final follow-up. Three patients experienced limitation of distance and duration of gait preoperatively because of radicular pain, and had no radicular symptom with unlimited gait at final follow-up.
Radiographic measurements for the curves in frontal plane are summarized in Table 3. The preoperative lower and principal thoracic curve tended to increase as the patients age increased (P<.05).
The degree of structural correction by surgery was not as great in more elderly patients, and this was particularly true for the thoracic curve. There were significant differences in the preoperative Cobb angle and postoperative Cobb angle among different age groups (P<.05). Similar tendencies were observed with the lumbar curves. The mean loss of correction during the follow-up period was 3° for thoracic curves and 4° for lumbar curves.
The results for the sagittal curvatures are summarized in Table 4. Preoperatively, thoracic kyphosis tended to be greater and lumbar lordosis smaller as the patients age increased. Postoperatively, thoracic kyphosis and lumbar lordosis generally were preserved within a reasonable range. The degree of correction by surgery tended to decrease as the patients age increased.
Coronal and sagittal balance is important in spinal fusion of adult idiopathic scoliosis, which influences the clinical outcome after spinal fusion of adult idiopathic scoliosis. To relieve lumbar pain and increase the function of lumbar, coronal and sagittal balance should be established. The recovery of spinal balance is closely related with long-term clinical outcome. The results for C7-S1 frontal imbalance are summarized in Table 5. A plumbline shift of the coronal plane >2.0 cm was found in 16 patients (40%) preoperatively, in 2 patients (13%) postoperatively, and in 3 patients (13%) at follow-up. The results for C7-S1 sagittal imbalance are summarized in Table 6. A plumbline shift of the sagittal plane >2.5 cm was found in 17 patients (43%) preoperatively, 4 patients (10%) postoperatively, and 6 patients (15%) at follow-up.
Overall, 7 patients experienced complications. One of the 7 patients who underwent surgery in their third decade had ileus, which was resolved without any sequelae. Among the 9 patients who underwent surgery in their fourth decade, 1 patient with late-onset deep infection required removal of all the implants, and 1 with pancreatitis was resolved with a nonfat diet without any adverse effect on the clinical outcome. One of the 14 patients who had pseudarthrosis associated with broken rods in their fifth decade underwent successful reoperation. Among the 9 patients in their sixth decade, 1 experienced acute and transient digestive tract complication, including nausea and vomiting 1 day postoperatively, which was resolved with conservative treatment (absolute diet and intravenous nutrition for 2 days) with no adverse effect on the clinical outcome; 1 experienced pseudarthrosis with broken rods and underwent successful reoperation; and 1 experienced disk herniation 2 years postoperatively in the nonfused lumbar spine, which was treated successfully by open diskectomy. The overall complication rate was 18% (7/39). There was no major neurologic deficit, death, or misplaced pedicle screw. At most recent follow-up, no pseudarthrosis was present, as determined by radiographic and clinical examination. Restoration of coronal and sagittal balance, or improvement thereof, was achieved in all patients with imbalance.
Increasing attention has been paid to treating adults with idiopathic scoliosis. It is now well established that untreated adult idiopathic scoliosis can lead to painful spinal osteoarthritis, progressive deformity, spinal stenosis with radiculopathy, muscle fatigue from coronal and sagittal plane imbalance, and psychological effects with a visible deformity. The operative indications for adult idiopathic scoliosis involve 1 or a combination of the following: documented and significant progression of frontal and sagittal deformities, uncontrollable back pain or back pain with radiculopathy, degrading cosmesis including frontal and sagittal imbalance, cardiopulmonary compromise and respiratory problems related to the chest deformity, and decreased chest compliance.11,13 In contrast to the adolescent with scoliosis, who usually is asymptomatic, the adult often presents with back pain. The incidence of pain associated with adult scoliosis is controversial, ranging from 40% to 90%.3,18
Surgery is complicated in adult idiopathic scoliosis patients. In adult idiopathic scoliosis, the spine usually becomes more rigid and surgical correction becomes more difficult. As the patients undergo degenerative changes in their scoliotic spine, the incidence and severity of pain (including back pain and back pain with radiculopathy) are elevated, but it is often difficult to precisely locate the lesion responsible for the pain. The surgical risks and complications are significantly higher in adults than in adolescents. Pseudarthrosis ranges from 0% to 27% and residual pain from 5% to 15%. Mortality ranges from 1% to 5%, neurologic problems from 1% to 5%, and thromboembolic problems from 1% to 20%.13,19 The goals of surgical treatment are to relieve back pain, prevent further progression of the curve and compromise of respiratory function, and improve cosmesis. Current instrumentation systems have markedly increased the efficacy of correction for spinal deformities in 3 dimensions and immediate stability of corrected spinal segments. Moreover, advances in anesthesiology and electrophysiologic monitoring have enabled surgeons to perform surgery in safer environments.
Back pain is likely the most common indication for surgical treatment of scoliosis in adult patients. There is no significant correlation between the severity of pain and the degree of scoiosis.20,21 The pain relief in the present study is similar to that already reported. Surgery is effective in decreasing the frequency and/or severity of pain.19,22 Back pain was improved mostly from stabilization via reduction and instrumentation. Numerous reports have documented the efficacy of surgery in the adult with scoliosis. Simmons et al13 reviewed a study that included 40 patients with adult idiopathic scoliosis that found a 90% success rate in the patients with a painful deformity, similar to the rate in other published series. Hu et al23 evaluated the outcomes of patients older than 40 years with major reconstructive surgery and found a satisfactory rate of 81%. Dickson et al22 found significantly better function in patients treated with surgery than those who refused surgery. However, absolute relief of back pain is often difficult to achieve, likely because these adult patients have varying degrees of lumbar degeneration. Regarding radicular pain, indirect decompression could be performed at these levels to restore spinal realignment with posterior instrumentation.
In the present study, posterior correction and spinal fusion with the third generation of pedicle screw construct gained popularity in the correction of scoliotic curve due to its perceived superior power of correction. Segmental fixation systems are the current gold standard and are designed to correct deformity in both frontal and sagittal planes with optimized fusion rates. Pedicle screws offer 3-column purchase and a longer arm compared with hook placement on the lamina. Instrumentation of each vertebral level with pedicle screws on the correcting side allows a more rigid fixation and reduces the stress concentration on any 1 screw during manipulation. This method also allows control of each instrumented segment, including the apex of curve, which in turn facilitates selective intersegmental compression, distraction, translation, and rotation.
The findings of the present study show that the preoperative lower and principal thoracic curve tended to increase as the patients age increased. Statistical analysis demonstrated significant differences between different age groups. The degree of correction by surgery tended to decrease in the more elderly patients. Correction of the thoracic curve particularly decreased as the patients age increased. Curves may become more rigid as age increases; however, statistical analysis demonstrates no significant differences between different age groups. Similar tendencies were observed with the lumbar curves.
Regarding the lumbar curves, few reports exist on radiographic changes in the sagittal plane in adult patients with idiopathic scoliosis.24 With Harrington instrumentation, lumbar lordosis decreased significantly postoperatively.25 The present studys results demonstrate that lumbar lordosis in adult patients with scoliosis is largely preserved after the pedicle screw placement, as has already been proved in adolescent patients.16 Improved initial stabilization and simultaneous correction of frontal and sagittal deformities are the fundamental advantages of segmental-type instrumentations.
For patients older than 50 years, Bridwell et al26 reported that both lumbar lordosis and AP spinal balance become difficult to control. However, all patients older than 50 years in the present study maintained preoperative lumbar lordosis postoperatively. Excision of 2 to 3 disks and cage to be filled with cancellous bone grafting were performed in the disk space by a posterior approach after posterior instrumentation surgery in 3 patients who had kyphotic segments or a large thoracolumbar or lumbar curve.
We believe that it is necessary to consider a long fusion in older patients who have extended lumbar degeneration, and that it is essential in patients with marked and rigid hypolordosis and interbody fusion. The overall complication rate of 18% in the present study is comparable with that previously reported, or even lower.22 Pseudarthrosis appears to be the most common complication in patients treated only via a posterior approach, and pseudarthrosis is difficult to judge with the implants in place. Although the definition differs from 1 author to another, the reported rate of pseudarthrosis after posterior surgery alone in adult patients with idiopathic scoliosis has varied from 9% to 18%.22 The present results with pedicle screw placement suggest a lower rate of pseudarthrosis than with other types of posterior instrumentations.
Different age groups had different distributions of curve types, curve magnitude, and fusion levels, which can affect the outcomes regardless of the age factor. However, this study clarified several important characteristics of adult scoliosis, and we believe that useful conclusions can be drawn regarding its surgical indications and strategies: (1) pedicle screw construct can gain effective results for treatment of adult idiopathic scoliosis due to its perceived superior power of correction; (2) younger patients present for surgery for different reasons than older patients (progressive deformity or pain); and (3) pain improvement is a more reliable outcome in older patients than younger patients, although younger patients rarely have severe pain symptoms.
- Smith JS, Shaffrey CI, Berven S, et al. Improvement of back pain with operative and nonoperative treatment in adults with scoliosis. Neurosurgery. 2009; 65(1):86-93.
- Ascani E, Bartolozzi P, Logroscino CA, et al. Natural history of untreated idiopathic scoliosis after skeletal maturity. Spine (Phila Pa 1976). 1986; 11(8):784-789.
- Weinstein SL, Zavala DC, Ponseti IV. Idiopathic scoliosis: long-term follow-up and prognosis in untreated patients. J Bone Joint Surg Am. 1981; 63(5):702-712.
- Weinstein SL, Ponseti IV. Curve progression in idiopathic scoliosis. J Bone Joint Surg Am. 1983; 65(4):447-455.
- Tan KJ, Moe MM, Vaithinathan R, Wong HK. Curve progression in idiopathic scoliosis: follow-up study to skeletal maturity. Spine (Phila Pa 1976). 2009; 34(7):697-700.
- Zhao JF, Sun RF, Xue WM, Gao G, Zhang JC, Pan XY. Application of halo-pelvic distraction to the treatment of adult idiopathic scoliosis [in Chinese]. Zhongguo Gu Shang. 2008; 21(6):457-458.
- Bradford DS. Adult scoliosis. Current concepts of treatment. Clin Orthop Relat Res. 1988; (229):70-87.
- Smith JS, Shaffrey CI, Berven S, et al. Improvement of back pain with operative and nonoperative treatment in adults with scoliosis. Neurosurgery. 2009; 65(1):86-93.
- Byrd JA III, Scoles PV, Winter RB, Bradford DS, Lonstein JE, Moe JH. Adult idiopathic scoliosis treated by anterior and posterior spinal fusion. J Bone Joint Surg Am. 1987; 69(6):843-850.
- Bridwell KH, Baldus C, Berven S, et al. Changes in radiographic and clinical outcomes with primary treatment adult spinal deformity surgeries from two years to three- to five-years follow-up. Spine (Phila Pa 1976). 2010; 35(20):1849-1854.
- Devlin VJ, Boachie-Adjei O, Bradford DS, Ogilvie JW, Transfeldt EE. Treatment of adult spinal deformity with fusion to the sacrum using CD instrumentation. J Spinal Disord. 1991; 4(1):1-14.
- Boachie-Adjei O, Bradford D. The Cotrel-Dubousset systemresults in spinal reconstruction. Early experience in 47 patients. Spine (Phila Pa 1976). 1991; 16(10):1155-1160.
- Simmons ED Jr, Kowalski JM, Simmons EH. The results of surgical treatment for adult scoliosis. Spine (Phila Pa 1976). 1993; 18(6):718-724.
- Ploumis A, Liu H, Mehbod AA, Transfeldt EE, Winter RB. A correlation of radiographic and functional measurements in adult degenerative scoliosis. Spine (Phila Pa 1976). 2009; 34(15):1581-1584.
- 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 (Phila Pa 1976). 2005; 30(14):1602-1609.
- Lee SM, Suk SI, Chung ER. Direct vertebral rotation: a new technique of three-dimensional deformity correction with segmental pedicle screw fixation in adolescent idiopathic scoliosis. Spine (Phila Pa 1976). 2004; 29(3):343-349.
- Nett MP. Postoperative pain management. Orthopedics. 2010; 33(9 Suppl):23-26.
- Grubb SA, Lipscomb HJ, Suh PB. Results of surgical treatment of painful adult scoliosis. Spine (Phila Pa 1976). 1994; 19914):1619-1627.
- Kitahara H, Inoue S, Minami S, Isobe K, Ohtsuka Y. Long-term results of spinal instrumentation surgery for scoliosis five years or more after surgery, in patients over twenty-three years of age. Spine (Phila Pa 1976). 1989; 14(7):744-749.
- Crawford CH III, Glassman SD. Surgical treatment of lumbar spinal stenosis associated with adult scoliosis. Instr Course Lect. 2009; (58):669-676.
- Mok JM, Cloyd JM, Bradford DS, et al. Reoperation after primary fusion for adult spinal deformity: rate, reason, and timing. Spine (Phila Pa 1976). 2009; 34(8):832-839.
- Dickson JH, Mirkovic S, Noble PC, Nalty T, Erwin WD. Results of operative treatment of idiopathic scoliosis in adults. J Bone Joint Surg Am. 1995; 77(4):513-523.
- Hu SS, Holly EA, Lele C, et al. Patient outcomes after spinal reconstructive surgery in patients > or = 40 years of age. J Spinal Disord. 1996; 9(6):460-469.
- Jackson RP, Simmons EH, Stripinis D. Coronal and sagittal plane spinal deformities correlating with back pain and pulmonary function in adult idiopathic scoliosis. Spine (Phila Pa 1976). 1989; 14(12):1391-1397.
- Sponseller PD, Cohen MS, Nachemson AL, Hall JE, Wohl ME. Results of surgical treatment of adults with idiopathic scoliosis. J Bone Joint Surg Am. 1987; 69(5):667-675.
- Bridwell KH, Betz R, Capelli AM, Huss G, Harvey C. Sagittal plane analysis in idiopathic scoliosis patients treated with Cotrel-Dubousset instrumentation. Spine (Phila Pa 1976). 1990; 15(7):644-649.
Drs Li, Xie, Zhao, and Zhu and Mr Wang are from the Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai, Dr Shen is from the Department of Orthopedics, Xuanwu Hospital , Beijing Capital Medical University, Beijing, Dr Gao is from the Department of Orthopedics, the ChinaJapan Union Hospital of Jilin University, Chang-chun, and Dr Fang is from the Department of Orthopedics, Beijing Shijitan Hospital, the Ninth Clinical Medical College of Peking University, Beijing, China.
Drs Li, Shen, Gao, Fang, Xie, Zhao, and Zhu and Mr Wang have no relevant financial relationships to disclose.
Drs Li, Shen, Gao, and Fang contributed equally to this article.
Correspondence should be addressed to: Xiutong Fang or Yu Shen, Department of Orthopedics, Beijing Shijitan Hospital, the Ninth Clinical Medical College of Peking University, Beijing, China (firstname.lastname@example.org).