spine
clinical article J Neurosurg Spine 22:194–198, 2015
Posterior-only spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique for treatment of severe and rigid scoliosis *Feng Shen, MD,1 Bin Zhou, MD,2 Quan Li, MD,1 Ming Li, MD,1 Zhiwei Wang, MD,1 Qiang Li, MD,2 and Bo Ran, MD2 1 Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; and 2Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province, China
Object The object of this study was to review the effectiveness in treating severe and rigid scoliosis with posterioronly spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique. Methods Twenty-eight patients with severe and rigid scoliosis (Cobb angle > 70° and flexibility < 30%) were retrospectively enrolled between June 2008 and June 2010. The average age of the patients was 17.1 years old (range 12–22 years old), 18 were female, and 10 were male. Etiological diagnoses were idiopathic in 24 patients, neuromuscular in 2 patients, and Marfan syndrome in 2 patients. All patients underwent posterior spinal release, derotation, translation, segmental correction, and an in situ rod-contouring technique. The scoliosis Cobb angle in the coronal plane, kyphosis Cobb angle, apex vertebral translation, and trunk shift were evaluated preoperatively and postoperatively. Results The average operative time was 241.8 ± 32.1 minutes and estimated blood loss was 780.5 ± 132.6 ml. The average scoliosis Cobb angle in the coronal plane was corrected from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively, with a correction ratio of 61.3%. The average kyphosis Cobb angle was 64.5° (range 59°–83°) preoperatively, which was decreased to 42.6° (range 34°–58°) postoperatively, with a correction ratio of 33.9%. After an average of 24 months of follow-up (range 13–30 months), no major complications were observed in these patients, except screw pullout of the upper thoracic vertebrae in 2 patients and screw penetration into the apical vertebrae in 1 patient. ConclusionS Posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique has proved to be a promising new technique for rigid scoliosis, significantly correcting the scoliosis and accompanied by fewer complications. http://thejns.org/doi/abs/10.3171/2014.10.SPINE13690
Key Words posterior release; in situ rod contouring; derotation; translation; segmental correction; scoliosis; technique; deformity
D
treatment of adolescent idiopathic scoliosis is a common condition in mainland China because of the lack of public education, medical insurance, or reluctance to undergo surgery, which leads to more severe and rigid deformity.11 In addition, scoliosis caused by a hemivertebra,1 Marfan syndrome,13 and neuromuscular lesions19 progresses fast and usually develops into severe scoliosis. However, the surgical treatment of severe and rigid scoliosis is currently challenging. Pathologically, the elayed
rigid segment is often located in the anterior and middle spinal columns, thus many scholars7,12,15 recommend performing the anterior release operation first so as to improve spinal flexibility, and then performing the posterior correction and bone fusion, which has achieved satisfactory results.11,16 However, anterior procedures are not ideal as they may increase operative time and estimated blood loss, as well as compromise pulmonary function.14 With a greater understanding of this disease, some scholars
Abbreviation SRS-22 = Scoliosis Research Society-22 questionnaire. submitted July 23, 2013. accepted October 2, 2014. include when citing Published online December 12, 2014; DOI: 10.3171/2014.10.SPINE13690. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. * Drs. Shen and Zhou contributed equally to this work. 194
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18/10 17.1 (12–22) 24 2 2 7 13 8
3.039 2.893 3.072 2.779 60.7% (46.8%–71.2%) 31.6% (26.4%–49.6%) 32 (15–41) 12 (1–19) 0.0037 0.0067 0.0035 0.0077 3.047 2.879 3.056 2.767 AVT = apex vertebral translation; TS = trunk shift. * Comparison between preoperative and immediately postoperative. † Comparison between preoperative and the last follow-up visit.
Sex (female/male) Mean age in yrs (range) Etiological diagnosis Idiopathic scoliosis Neuromuscular scoliosis Scoliosis associated w/ Marfan syndrome Scoliosis curve type Thoracic major curve Thoracolumbar major curve Lumbar major curves
85.7° (77°–94°) 64.5° (59°–83°) 81 (35–108) 23 (2–33)
No. of Patients
Mean Cobb angle (range) Coronal plane Sagittal plane Mean AVT in mm (range) Mean TS in mm (range)
Parameter
Preop
TABLE 1. Demographic data of 28 patients with severe and rigid scoliosis
TABLE 2. Spinal deformity correction outcome
Surgical Procedure Preoperatively, all patients underwent the pulmonary function test and balloon-blowing exercise to improve lung capacity. A suspension exercise was also performed to improve the flexibility of scoliosis segments. All patients underwent general anesthesia and were placed
Clinical Index
Immediately Postop
Correction Immediately Postop
t Score*
p Value
Patient Population All study participants provided written informed consent prior to their inclusion in the study, and all human studies were approved by the China Ethics Committee and performed in accordance with ethical standards. Twentyeight patients with severe and rigid scoliosis (Cobb angle > 70° and flexibility < 30%) who underwent posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique were retrospectively enrolled between June 2008 and June 2010. The average age of the patients at surgery was 17.1 years (range 12–22 years) and the female/male ratio was 9/5. Etiological diagnoses were idiopathic scoliosis in 24 patients, neuromuscular scoliosis in 2 patients, and scoliosis associated with Marfan syndrome in 2 patients. The average scoliosis Cobb angle in the coronal plane was 85.7° (range 77°–94°), the average kyphosis Cobb angle in the sagittal plane was 64.5° (59°–83°), and the average flexibility was 22.1% (range 7%–27.8%). Seven patients had a thoracic scoliosis, 13 had thoracolumbar scoliosis, and 8 had lumbar deformation (Tables 1 and 2). The surgery for each patient was performed by the first author (F.S.).
61.3% (43.7%–72.4%) 33.9% (23.2%–49.6%) 37 (14–48) 13 (1–18)
Methods
33.1° (21°–52°) 42.6° (34°–58°) 44 (15–85) 10 (1–20)
Correction at Last Follow-Up
t Score†
p Value
have suggested that contraction of the posterior spinal structures and fusion of the costotransverse, intercostal, and intratransverse joints may also play important roles in the rigid spinal deformity; thus, a posterior-only approach is advocated.4,20 Using segmental pedicle screw spinal instrumentation and vertebral derotation, many authors have reported a loss of thoracic kyphosis postoperatively, but segmental sagittal imbalance correction has been achieved by in situ contouring.2,3 Therefore, we adopted a posterior release operation combined with derotation, translation, segmental correction, and an in situ rod-contouring technique to alleviate severe and rigid scoliosis.
0.0045 0.0071 0.0031 0.0075
Operative treatment for severe and rigid scoliosis
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prone on a surgical table. According to the theory of 3D scoliosis correction, apex vertebrae, upper and lower end vertebrae, and stable vertebrae were located and then the pedicle screws were inserted using a freehand technique. The contractural soft tissues in the concave side were released and the intertransverse ligament and costotransverse joint ligament in the rigid segment—including the ribs and transverse process in some cases—were excised followed by placement of a rigid rod. Correction of the curve was performed by rod derotation. Another new rod was then placed and locked in the convex side, and the rod in the concave side was removed. Two force application sites were selected in the convex rod to link the in situ rod-bending device. Compression in the coronal and sagittal planes was performed to correct the spinal deformity. After satisfactory results were achieved, the rod in the concave side was replaced, followed by segmental distraction of locking screws. Finally, the in situ rod-bending device was removed and 2 rods were connected by transverse connectors at both ends of the construct. Autogenous bone or allograft was then selected for posterior fusion at the segments. An antibiotic was used 1 day before the operation and every day after the operation for 8–10 days. Active motion with a brace was performed from the third week after the operation. The brace protection was removed at 3 months after the operation. Outcome Measures The radiograph was examined in all patients every 3 months after the operations so as to observe the bone union and correction effect. The following indices were recorded: 1) the scoliosis Cobb angle in the coronal plane; 2) the kyphosis Cobb angle in the sagittal plane; 3) the apex vertebral translation, which was measured as the distance from the perpendicular line drawn from the center of the S-1 vertebral body (center sacral vertical line) to the midpoint of the apical vertebral body of the curve; and 4) the trunk shift, which was determined as the distance between the vertical line drawn from the C-7 spinous process and the center sacral line. Neurological function was evaluated by the Frankel grade: A, complete motor and sensory loss; B, has sensation but has lost all motor function; C, motor function present, but no practical use (nonambulatory); D, ambulatory; and E, completely normal. The Scoliosis Research Society-22 questionnaire (SRS-22) was used for the assessment of health-related quality of life in patients preoperatively and at the final follow-up evaluation. Total scores as well as individual domain scores for pain, selfimage, function, mental health, and satisfaction parameters were calculated and analyzed for each patient. Statistical Analysis All data were analyzed by SPSS statistical analysis software (version 13.0, SPSS Inc.). The difference between each preoperative and postoperative index was analyzed by a t-test. The correction ratio was calculated using the formula: postoperative index - preoperative index/postoperative index
A p value < 0.05 was considered statistically significant. 196
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Results
All patients were successfully treated by the posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique, with an average operative time of 241.8 ± 32.1 minutes and estimated blood loss of 780.5 ± 132.6 ml. The average scoliosis Cobb angle in the coronal plane was corrected from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively, resulting in the correction ratio of 61.3% (Table 2). The average kyphosis Cobb angle in the sagittal plane was corrected from 64.5° (range 59°– 83°) preoperatively to 42.6° (range 34°–58°) postoperatively (Table 2). After the average 24-month follow-up (range 13–30 months), we only found a few screw-related complications, including screw pullout of the upper thoracic vertebrae in 2 patients and screw penetration into the apical vertebrae in 1 patient. In addition, 1 patient appeared to have numbness and muscle weakness in both lower limbs (Frankel C), which recovered to Frankel Grade E 1 month after the operation. All fixed segments were completely fused and no wound infection or pseudarthrosis was present in these 28 patients. The SRS-22 scores were significantly improved at the last follow-up evaluation compared with that present during the preoperative period (Table 3). A typical case is shown in Fig. 1.
Discussion
According to the theory of 3D scoliosis correction, spinal deformity and flexibility can be well corrected by concave rod derotation, segment distraction, and convex rod support.10 The corrective ability of this approach is associated with 2 main factors: the solidity between the internal fixation and the bone, and the metal rod strength. The precontoured titanium rod used at present cannot provide a satisfactory stiffness to overcome the rigid deformity of scoliosis. Thus, the excellent correction effect may not be obtained for severe and rigid scoliosis using traditional precontoured rod derotation. In contrast, the in situ rod-contouring technique can provide greater strength to directly correct the scoliosis rigid deformity.17,18 As expected, our results indicated that a good correction ratio was obtained in the scoliosis Cobb angle in the coronal plane, from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively. The in situ rod-contouring technique is not usually used because it may lead to bone fracture and neurologiTABLE 3. Scores on the SRS-22 preoperatively and at last follow-up* Domains
Preop
Last Follow-Up†
Function/activity Pain Self-image Mental health Satisfaction w/ management
3.5 ± 0.42 3.3 ± 0.61 3.2 ± 0.49 3.3 ± 0.65 2.9 ± 0.69
4.7 ± 0.60 4.6 ± 0.71 4.3 ± 0.55 4.2 ± 0.54 4.1 ± 0.62
* Scores are presented as the mean ± SD. † All values were statistically significant compared with preoperative values (p < 0.05).
Operative treatment for severe and rigid scoliosis
FIG. 1. Images obtained from an 18-year-old female patient with idiopathic scoliosis. A and B: Photographs before (A) and after (B) the operation. C and D: Preoperative anteroposterior (C) and lateral (D) radiographs. E and F: Anteroposterior (E) and lateral (F) radiographs obtained immediately after the operation. G and H: Anteroposterior (G) and lateral (H) radiographs obtained 12 months after the operation. Figure is available in color online only.
cal complications. The above risks come from the use of vertebral pedicle hooks and vertebral plate hooks.21 But with the development of pedicle screws, especially pedicle screws for the upper thoracic spine, the in situ rod-contouring technique has attracted more attention from investigators.8 The pedicle screws not only can increase the immobility between the internal fixation and the bone, but also can control the vertebra effectively.9 However, pedicle screw penetration and pullout occasionally occur with the in situ rod-contouring technique, especially on the convex side. This may be attributable to the correction role of the convex rod, but also the supporting and maintaining effect of the concave rod. To decrease the operative complications we placed the rod in the concave side twice so as to disperse the strength of the convex vertebra pedicle screws. It has been reported that the more internal fixation points there are, the more the strength is dispersed, which
leads to a reduced possibility of pedicle screw penetration and pullout phenomena. In addition, Kubo et al.6 reported that the release of the posterior contractural tissues could improve spinal flexibility. Thus, in this study, the contractural soft tissues in the concave side were released and the intertransverse ligament and costotransverse joint ligament in the rigid segment were cut, which may improve the flexibility of the spinal posterior rigid deformity segments and lead to a good correction effect after the operation. This indirectly demonstrates that the anterior release operation is unnecessary. However, there are still some limitations in this study. Only 2 patients with scoliosis caused by Marfan syndrome and 2 with scoliosis caused by a neuromuscular disease were included, which are different from idiopathic scoliosis. The anterior release operation not only can improve J Neurosurg Spine Volume 22 • February 2015
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spinal flexibility but also prevent occurrence of the crankshaft phenomenon in the treatment of the scoliosis. Kioschos et al.5 used posterior pedicle screw internal fixation in the lumbar vertebrae of the canine and found that the posterior pedicle screw internal fixation system could control the anterior growth center of the spine and prevent the crankshaft phenomenon, even if no anterior release and fusion operation were performed. However, the crankshaft phenomenon was not recorded because of the short follow-up period in this study.
Conclusions
Posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique has proved to be a promising new technique for rigid scoliosis, significantly correcting the scoliosis and accompanied by fewer complications. However, further multicenter studies with a large sample size and a long-term follow-up period are needed before definitive conclusions can be made.
References
1. Aydogan M, Ozturk C, Tezer M, Mirzanli C, Karatoprak O, Hamzaoglu A: Posterior vertebrectomy in kyphosis, scoliosis and kyphoscoliosis due to hemivertebra. J Pediatr Orthop B 17:33–37, 2008 2. Charles YP, Bouchaïb J, Walter A, Schuller S, Sauleau EA, Steib JP: Sagittal balance correction of idiopathic scoliosis using the in situ contouring technique. Eur Spine J 21:1950– 1956, 2012 3. Cidambi KR, Glaser DA, Bastrom TP, Nunn TN, Ono T, Newton PO: Postoperative changes in spinal rod contour in adolescent idiopathic scoliosis: an in vivo deformation study. Spine (Phila Pa 1976) 37:1566–1572, 2012 4. Keeler KA, Lenke LG, Good CR, Bridwell KH, Sides B, Luhmann SJ: Spinal fusion for spastic neuromuscular scoliosis: is anterior releasing necessary when intraoperative halofemoral traction is used? Spine (Phila Pa 1976) 35:E427– E433, 2010 5. Kioschos HC, Asher MA, Lark RG, Harner EJ: Overpowering the crankshaft mechanism. The effect of posterior spinal fusion with and without stiff transpedicular fixation on anterior spinal column growth in immature canines. Spine (Phila Pa 1976) 21:1168–1173, 1996 6. Kubo S, Tajima N, Chosa E, Kuroki H, Goto K: Posterior releasing techniques for idiopathic scoliosis: microscopic discectomy and transverse process resection: a technical note. J Spinal Disord Tech 16:528–533, 2003 7. Kuklo TR, Lehman RA Jr, Lenke LG: Structures at risk following anterior instrumented spinal fusion for thoracic adolescent idiopathic scoliosis. J Spinal Disord Tech 18 Suppl:S58–S64, 2005 8. Kuntz C IV, Maher PC, Levine NB, Kurokawa R: Prospective evaluation of thoracic pedicle screw placement using fluoroscopic imaging. J Spinal Disord Tech 17:206–214, 2004 9. Lamartina C, Petruzzi M, Macchia M, Stradiotti P, Zerbi A: Role of rod diameter in comparison between only screws versus hooks and screws in posterior instrumentation of tho-
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racic curve in idiopathic scoliosis. Eur Spine J 20 (Suppl 1): S85–S89, 2011 10. 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) 29:343–349, 2004 11. Li M, Ni J, Li Y, Fang X, Gu S, Zhang Z, et al: Single-staged anterior and posterior spinal fusion: a safe and effective alternative for severe and rigid adolescent idiopathic scoliosis in China. J Paediatr Child Health 45:246–253, 2009 12. Liljenqvist UR, Allkemper T, Hackenberg L, Link TM, Steinbeck J, Halm HF: Analysis of vertebral morphology in idiopathic scoliosis with use of magnetic resonance imaging and multiplanar reconstruction. J Bone Joint Surg Am 84A:359–368, 2002 13. Lipton GE, Guille JT, Kumar SJ: Surgical treatment of scoliosis in Marfan syndrome: guidelines for a successful outcome. J Pediatr Orthop 22:302–307, 2002 14. Lonner BS, Auerbach JD, Estreicher MB, Betz RR, Crawford AH, Lenke LG, et al: Pulmonary function changes after various anterior approaches in the treatment of adolescent idiopathic scoliosis. J Spinal Disord Tech 22:551–558, 2009 15. Modi H, Suh SW, Song HR, Yang JH: Accuracy of thoracic pedicle screw placement in scoliosis using the ideal pedicle entry point during the freehand technique. Int Orthop 33:469–475, 2009 16. Shen J, Qiu G, Wang Y, Zhang Z, Zhao Y: Comparison of 1-stage versus 2-stage anterior and posterior spinal fusion for severe and rigid idiopathic scoliosis—a randomized prospective study. Spine (Phila Pa 1976) 31:2525–2528, 2006 17. Steib JP, Aoui M, Mitulescu A, Bogorin I, Chiffolot X, Cognet JM, et al: Thoracolumbar fractures surgically treated by “in situ contouring.” Eur Spine J 15:1823–1832, 2006 18. Steib JP, Dumas R, Mitton D, Skalli W: Surgical correction of scoliosis by in situ contouring: a detorsion analysis. Spine (Phila Pa 1976) 29:193–199, 2004 19. Suh SW, Modi HN, Yang J, Song HR, Jang KM: Posterior multilevel vertebral osteotomy for correction of severe and rigid neuromuscular scoliosis: a preliminary study. Spine (Phila Pa 1976) 34:1315–1320, 2009 20. Suk SI, Kim JH, Cho KJ, Kim SS, Lee JJ, Han YT: Is anterior release necessary in severe scoliosis treated by posterior segmental pedicle screw fixation? Eur Spine J 16:1359– 1365, 2007 21. Suk SI, Lee CK, Min HJ, Cho KH, Oh JH: Comparison of Cotrel-Dubousset pedicle screws and hooks in the treatment of idiopathic scoliosis. Int Orthop 18:341–346, 1994
Author Contributions
Conception and design: Ran, Shen, Quan Li, Wang. Acquisition of data: Shen, Zhou, Quan Li. Analysis and interpretation of data: Shen, Zhou, Quan Li. Drafting the article: Qiang Li, Ran. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Ran. Statistical analysis: M Li, Wang. Administrative/technical/material support: Ran. Study supervision: Ran.
Correspondence
Bo Ran, Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College, No. 99 Huaihai West Rd., Xuzhou, Jiangsu Province 221000, China. email: [email protected].
clinical article J Neurosurg Spine 22:194–198, 2015
Posterior-only spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique for treatment of severe and rigid scoliosis *Feng Shen, MD,1 Bin Zhou, MD,2 Quan Li, MD,1 Ming Li, MD,1 Zhiwei Wang, MD,1 Qiang Li, MD,2 and Bo Ran, MD2 1 Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai; and 2Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province, China
Object The object of this study was to review the effectiveness in treating severe and rigid scoliosis with posterioronly spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique. Methods Twenty-eight patients with severe and rigid scoliosis (Cobb angle > 70° and flexibility < 30%) were retrospectively enrolled between June 2008 and June 2010. The average age of the patients was 17.1 years old (range 12–22 years old), 18 were female, and 10 were male. Etiological diagnoses were idiopathic in 24 patients, neuromuscular in 2 patients, and Marfan syndrome in 2 patients. All patients underwent posterior spinal release, derotation, translation, segmental correction, and an in situ rod-contouring technique. The scoliosis Cobb angle in the coronal plane, kyphosis Cobb angle, apex vertebral translation, and trunk shift were evaluated preoperatively and postoperatively. Results The average operative time was 241.8 ± 32.1 minutes and estimated blood loss was 780.5 ± 132.6 ml. The average scoliosis Cobb angle in the coronal plane was corrected from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively, with a correction ratio of 61.3%. The average kyphosis Cobb angle was 64.5° (range 59°–83°) preoperatively, which was decreased to 42.6° (range 34°–58°) postoperatively, with a correction ratio of 33.9%. After an average of 24 months of follow-up (range 13–30 months), no major complications were observed in these patients, except screw pullout of the upper thoracic vertebrae in 2 patients and screw penetration into the apical vertebrae in 1 patient. ConclusionS Posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique has proved to be a promising new technique for rigid scoliosis, significantly correcting the scoliosis and accompanied by fewer complications. http://thejns.org/doi/abs/10.3171/2014.10.SPINE13690
Key Words posterior release; in situ rod contouring; derotation; translation; segmental correction; scoliosis; technique; deformity
D
treatment of adolescent idiopathic scoliosis is a common condition in mainland China because of the lack of public education, medical insurance, or reluctance to undergo surgery, which leads to more severe and rigid deformity.11 In addition, scoliosis caused by a hemivertebra,1 Marfan syndrome,13 and neuromuscular lesions19 progresses fast and usually develops into severe scoliosis. However, the surgical treatment of severe and rigid scoliosis is currently challenging. Pathologically, the elayed
rigid segment is often located in the anterior and middle spinal columns, thus many scholars7,12,15 recommend performing the anterior release operation first so as to improve spinal flexibility, and then performing the posterior correction and bone fusion, which has achieved satisfactory results.11,16 However, anterior procedures are not ideal as they may increase operative time and estimated blood loss, as well as compromise pulmonary function.14 With a greater understanding of this disease, some scholars
Abbreviation SRS-22 = Scoliosis Research Society-22 questionnaire. submitted July 23, 2013. accepted October 2, 2014. include when citing Published online December 12, 2014; DOI: 10.3171/2014.10.SPINE13690. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. * Drs. Shen and Zhou contributed equally to this work. 194
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18/10 17.1 (12–22) 24 2 2 7 13 8
3.039 2.893 3.072 2.779 60.7% (46.8%–71.2%) 31.6% (26.4%–49.6%) 32 (15–41) 12 (1–19) 0.0037 0.0067 0.0035 0.0077 3.047 2.879 3.056 2.767 AVT = apex vertebral translation; TS = trunk shift. * Comparison between preoperative and immediately postoperative. † Comparison between preoperative and the last follow-up visit.
Sex (female/male) Mean age in yrs (range) Etiological diagnosis Idiopathic scoliosis Neuromuscular scoliosis Scoliosis associated w/ Marfan syndrome Scoliosis curve type Thoracic major curve Thoracolumbar major curve Lumbar major curves
85.7° (77°–94°) 64.5° (59°–83°) 81 (35–108) 23 (2–33)
No. of Patients
Mean Cobb angle (range) Coronal plane Sagittal plane Mean AVT in mm (range) Mean TS in mm (range)
Parameter
Preop
TABLE 1. Demographic data of 28 patients with severe and rigid scoliosis
TABLE 2. Spinal deformity correction outcome
Surgical Procedure Preoperatively, all patients underwent the pulmonary function test and balloon-blowing exercise to improve lung capacity. A suspension exercise was also performed to improve the flexibility of scoliosis segments. All patients underwent general anesthesia and were placed
Clinical Index
Immediately Postop
Correction Immediately Postop
t Score*
p Value
Patient Population All study participants provided written informed consent prior to their inclusion in the study, and all human studies were approved by the China Ethics Committee and performed in accordance with ethical standards. Twentyeight patients with severe and rigid scoliosis (Cobb angle > 70° and flexibility < 30%) who underwent posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique were retrospectively enrolled between June 2008 and June 2010. The average age of the patients at surgery was 17.1 years (range 12–22 years) and the female/male ratio was 9/5. Etiological diagnoses were idiopathic scoliosis in 24 patients, neuromuscular scoliosis in 2 patients, and scoliosis associated with Marfan syndrome in 2 patients. The average scoliosis Cobb angle in the coronal plane was 85.7° (range 77°–94°), the average kyphosis Cobb angle in the sagittal plane was 64.5° (59°–83°), and the average flexibility was 22.1% (range 7%–27.8%). Seven patients had a thoracic scoliosis, 13 had thoracolumbar scoliosis, and 8 had lumbar deformation (Tables 1 and 2). The surgery for each patient was performed by the first author (F.S.).
61.3% (43.7%–72.4%) 33.9% (23.2%–49.6%) 37 (14–48) 13 (1–18)
Methods
33.1° (21°–52°) 42.6° (34°–58°) 44 (15–85) 10 (1–20)
Correction at Last Follow-Up
t Score†
p Value
have suggested that contraction of the posterior spinal structures and fusion of the costotransverse, intercostal, and intratransverse joints may also play important roles in the rigid spinal deformity; thus, a posterior-only approach is advocated.4,20 Using segmental pedicle screw spinal instrumentation and vertebral derotation, many authors have reported a loss of thoracic kyphosis postoperatively, but segmental sagittal imbalance correction has been achieved by in situ contouring.2,3 Therefore, we adopted a posterior release operation combined with derotation, translation, segmental correction, and an in situ rod-contouring technique to alleviate severe and rigid scoliosis.
0.0045 0.0071 0.0031 0.0075
Operative treatment for severe and rigid scoliosis
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195
F. Shen et al.
prone on a surgical table. According to the theory of 3D scoliosis correction, apex vertebrae, upper and lower end vertebrae, and stable vertebrae were located and then the pedicle screws were inserted using a freehand technique. The contractural soft tissues in the concave side were released and the intertransverse ligament and costotransverse joint ligament in the rigid segment—including the ribs and transverse process in some cases—were excised followed by placement of a rigid rod. Correction of the curve was performed by rod derotation. Another new rod was then placed and locked in the convex side, and the rod in the concave side was removed. Two force application sites were selected in the convex rod to link the in situ rod-bending device. Compression in the coronal and sagittal planes was performed to correct the spinal deformity. After satisfactory results were achieved, the rod in the concave side was replaced, followed by segmental distraction of locking screws. Finally, the in situ rod-bending device was removed and 2 rods were connected by transverse connectors at both ends of the construct. Autogenous bone or allograft was then selected for posterior fusion at the segments. An antibiotic was used 1 day before the operation and every day after the operation for 8–10 days. Active motion with a brace was performed from the third week after the operation. The brace protection was removed at 3 months after the operation. Outcome Measures The radiograph was examined in all patients every 3 months after the operations so as to observe the bone union and correction effect. The following indices were recorded: 1) the scoliosis Cobb angle in the coronal plane; 2) the kyphosis Cobb angle in the sagittal plane; 3) the apex vertebral translation, which was measured as the distance from the perpendicular line drawn from the center of the S-1 vertebral body (center sacral vertical line) to the midpoint of the apical vertebral body of the curve; and 4) the trunk shift, which was determined as the distance between the vertical line drawn from the C-7 spinous process and the center sacral line. Neurological function was evaluated by the Frankel grade: A, complete motor and sensory loss; B, has sensation but has lost all motor function; C, motor function present, but no practical use (nonambulatory); D, ambulatory; and E, completely normal. The Scoliosis Research Society-22 questionnaire (SRS-22) was used for the assessment of health-related quality of life in patients preoperatively and at the final follow-up evaluation. Total scores as well as individual domain scores for pain, selfimage, function, mental health, and satisfaction parameters were calculated and analyzed for each patient. Statistical Analysis All data were analyzed by SPSS statistical analysis software (version 13.0, SPSS Inc.). The difference between each preoperative and postoperative index was analyzed by a t-test. The correction ratio was calculated using the formula: postoperative index - preoperative index/postoperative index
A p value < 0.05 was considered statistically significant. 196
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Results
All patients were successfully treated by the posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique, with an average operative time of 241.8 ± 32.1 minutes and estimated blood loss of 780.5 ± 132.6 ml. The average scoliosis Cobb angle in the coronal plane was corrected from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively, resulting in the correction ratio of 61.3% (Table 2). The average kyphosis Cobb angle in the sagittal plane was corrected from 64.5° (range 59°– 83°) preoperatively to 42.6° (range 34°–58°) postoperatively (Table 2). After the average 24-month follow-up (range 13–30 months), we only found a few screw-related complications, including screw pullout of the upper thoracic vertebrae in 2 patients and screw penetration into the apical vertebrae in 1 patient. In addition, 1 patient appeared to have numbness and muscle weakness in both lower limbs (Frankel C), which recovered to Frankel Grade E 1 month after the operation. All fixed segments were completely fused and no wound infection or pseudarthrosis was present in these 28 patients. The SRS-22 scores were significantly improved at the last follow-up evaluation compared with that present during the preoperative period (Table 3). A typical case is shown in Fig. 1.
Discussion
According to the theory of 3D scoliosis correction, spinal deformity and flexibility can be well corrected by concave rod derotation, segment distraction, and convex rod support.10 The corrective ability of this approach is associated with 2 main factors: the solidity between the internal fixation and the bone, and the metal rod strength. The precontoured titanium rod used at present cannot provide a satisfactory stiffness to overcome the rigid deformity of scoliosis. Thus, the excellent correction effect may not be obtained for severe and rigid scoliosis using traditional precontoured rod derotation. In contrast, the in situ rod-contouring technique can provide greater strength to directly correct the scoliosis rigid deformity.17,18 As expected, our results indicated that a good correction ratio was obtained in the scoliosis Cobb angle in the coronal plane, from 85.7° (range 77°–94°) preoperatively to 33.1° (range 21°–52°) postoperatively. The in situ rod-contouring technique is not usually used because it may lead to bone fracture and neurologiTABLE 3. Scores on the SRS-22 preoperatively and at last follow-up* Domains
Preop
Last Follow-Up†
Function/activity Pain Self-image Mental health Satisfaction w/ management
3.5 ± 0.42 3.3 ± 0.61 3.2 ± 0.49 3.3 ± 0.65 2.9 ± 0.69
4.7 ± 0.60 4.6 ± 0.71 4.3 ± 0.55 4.2 ± 0.54 4.1 ± 0.62
* Scores are presented as the mean ± SD. † All values were statistically significant compared with preoperative values (p < 0.05).
Operative treatment for severe and rigid scoliosis
FIG. 1. Images obtained from an 18-year-old female patient with idiopathic scoliosis. A and B: Photographs before (A) and after (B) the operation. C and D: Preoperative anteroposterior (C) and lateral (D) radiographs. E and F: Anteroposterior (E) and lateral (F) radiographs obtained immediately after the operation. G and H: Anteroposterior (G) and lateral (H) radiographs obtained 12 months after the operation. Figure is available in color online only.
cal complications. The above risks come from the use of vertebral pedicle hooks and vertebral plate hooks.21 But with the development of pedicle screws, especially pedicle screws for the upper thoracic spine, the in situ rod-contouring technique has attracted more attention from investigators.8 The pedicle screws not only can increase the immobility between the internal fixation and the bone, but also can control the vertebra effectively.9 However, pedicle screw penetration and pullout occasionally occur with the in situ rod-contouring technique, especially on the convex side. This may be attributable to the correction role of the convex rod, but also the supporting and maintaining effect of the concave rod. To decrease the operative complications we placed the rod in the concave side twice so as to disperse the strength of the convex vertebra pedicle screws. It has been reported that the more internal fixation points there are, the more the strength is dispersed, which
leads to a reduced possibility of pedicle screw penetration and pullout phenomena. In addition, Kubo et al.6 reported that the release of the posterior contractural tissues could improve spinal flexibility. Thus, in this study, the contractural soft tissues in the concave side were released and the intertransverse ligament and costotransverse joint ligament in the rigid segment were cut, which may improve the flexibility of the spinal posterior rigid deformity segments and lead to a good correction effect after the operation. This indirectly demonstrates that the anterior release operation is unnecessary. However, there are still some limitations in this study. Only 2 patients with scoliosis caused by Marfan syndrome and 2 with scoliosis caused by a neuromuscular disease were included, which are different from idiopathic scoliosis. The anterior release operation not only can improve J Neurosurg Spine Volume 22 • February 2015
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spinal flexibility but also prevent occurrence of the crankshaft phenomenon in the treatment of the scoliosis. Kioschos et al.5 used posterior pedicle screw internal fixation in the lumbar vertebrae of the canine and found that the posterior pedicle screw internal fixation system could control the anterior growth center of the spine and prevent the crankshaft phenomenon, even if no anterior release and fusion operation were performed. However, the crankshaft phenomenon was not recorded because of the short follow-up period in this study.
Conclusions
Posterior spinal release combined with derotation, translation, segmental correction, and an in situ rod-contouring technique has proved to be a promising new technique for rigid scoliosis, significantly correcting the scoliosis and accompanied by fewer complications. However, further multicenter studies with a large sample size and a long-term follow-up period are needed before definitive conclusions can be made.
References
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racic curve in idiopathic scoliosis. Eur Spine J 20 (Suppl 1): S85–S89, 2011 10. 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) 29:343–349, 2004 11. Li M, Ni J, Li Y, Fang X, Gu S, Zhang Z, et al: Single-staged anterior and posterior spinal fusion: a safe and effective alternative for severe and rigid adolescent idiopathic scoliosis in China. J Paediatr Child Health 45:246–253, 2009 12. Liljenqvist UR, Allkemper T, Hackenberg L, Link TM, Steinbeck J, Halm HF: Analysis of vertebral morphology in idiopathic scoliosis with use of magnetic resonance imaging and multiplanar reconstruction. J Bone Joint Surg Am 84A:359–368, 2002 13. Lipton GE, Guille JT, Kumar SJ: Surgical treatment of scoliosis in Marfan syndrome: guidelines for a successful outcome. J Pediatr Orthop 22:302–307, 2002 14. Lonner BS, Auerbach JD, Estreicher MB, Betz RR, Crawford AH, Lenke LG, et al: Pulmonary function changes after various anterior approaches in the treatment of adolescent idiopathic scoliosis. J Spinal Disord Tech 22:551–558, 2009 15. Modi H, Suh SW, Song HR, Yang JH: Accuracy of thoracic pedicle screw placement in scoliosis using the ideal pedicle entry point during the freehand technique. Int Orthop 33:469–475, 2009 16. Shen J, Qiu G, Wang Y, Zhang Z, Zhao Y: Comparison of 1-stage versus 2-stage anterior and posterior spinal fusion for severe and rigid idiopathic scoliosis—a randomized prospective study. Spine (Phila Pa 1976) 31:2525–2528, 2006 17. Steib JP, Aoui M, Mitulescu A, Bogorin I, Chiffolot X, Cognet JM, et al: Thoracolumbar fractures surgically treated by “in situ contouring.” Eur Spine J 15:1823–1832, 2006 18. Steib JP, Dumas R, Mitton D, Skalli W: Surgical correction of scoliosis by in situ contouring: a detorsion analysis. Spine (Phila Pa 1976) 29:193–199, 2004 19. Suh SW, Modi HN, Yang J, Song HR, Jang KM: Posterior multilevel vertebral osteotomy for correction of severe and rigid neuromuscular scoliosis: a preliminary study. Spine (Phila Pa 1976) 34:1315–1320, 2009 20. Suk SI, Kim JH, Cho KJ, Kim SS, Lee JJ, Han YT: Is anterior release necessary in severe scoliosis treated by posterior segmental pedicle screw fixation? Eur Spine J 16:1359– 1365, 2007 21. Suk SI, Lee CK, Min HJ, Cho KH, Oh JH: Comparison of Cotrel-Dubousset pedicle screws and hooks in the treatment of idiopathic scoliosis. Int Orthop 18:341–346, 1994
Author Contributions
Conception and design: Ran, Shen, Quan Li, Wang. Acquisition of data: Shen, Zhou, Quan Li. Analysis and interpretation of data: Shen, Zhou, Quan Li. Drafting the article: Qiang Li, Ran. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Ran. Statistical analysis: M Li, Wang. Administrative/technical/material support: Ran. Study supervision: Ran.
Correspondence
Bo Ran, Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College, No. 99 Huaihai West Rd., Xuzhou, Jiangsu Province 221000, China. email: [email protected].
