eP

RIMARY

RESEARCH

Comparison of Thoracoscopic Anterior Release Combined With Posterior Spinal Fusion Versus Posterior-only Approach With an All-pedicle Screw Construct in the Treatment of Rigid Thoracic Adolescent Idiopathic Scoliosis Zhicai Shi, MD,* Jiayu Chen, MD,*w Chao Wang, MM,*z Ming Li, MD,* Quan Li, MD,* Ye Zhang, MD,y Cheng Li, MM,8 Yuehua Qiao, MM,z Guo Kaijin, MD,8 Chen Xiangyang, MD,8 and Bo Ran, PD8*

Objective: To compare the effect of thoracoscopic anterior release combined with posterior spinal fusion and posterior-only approach with an all-pedicle screw construct in the treatment of rigid thoracic adolescent idiopathic scoliosis. Methods: From June 2001 to June 2010, 63 patients who were admitted to our hospital with thoracic Cobb angle Z80 degrees and the flexibility r40% were enrolled in our study. They were treated with either a combined anterior/posterior spinal fusion with hooks and screws (group A, n = 25) or a posterior spinal fusion alone with an all-pedicle screw construct (group B, n = 38). The thoracic Cobb angle in the standing whole-spine anteroposterior x-ray, thoracic kyphosis (T5–T12) Cobb angle, imaging examination parameters, fixation segments, implant density, and complications between the 2 groups were compared. Results: There were no significant differences in operation time, bleeding volume, length of hospital stay, preoperative coronal, sagittal Cobb, coronal curve flexibility, or postoperative coronal Cobb correction ratio between the 2 groups. Moreover, no significant difference in the Scoliosis Research Society-22 score at the last follow-up was present in the 2 groups, although it had Received for publication January 29, 2013; accepted June 12, 2013. From the *Department of Orthopaedics, Changhai Hospital Affiliated to the Second Medical University, Shanghai; wDepartment of Orthopedics, Kunming General Hospital of Chengdu Military Command, Kunming; zDepartment of Orthopedic Injury, General Hospital of Jinan Military Command, Jinan, Shandong Province; yDepartment of Orthopedics, People’s Liberation Army 161 Hospital, Wuhan, Hubei Province; 8Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College; and zTeaching and Research Department of Otorhinolaryngology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province, China. Z.S., J.C., and C.W. are co-first authors. M.L. and Q.L. are regarded as co-corresponding authors. The authors declare no conflict of interest. Correspondence: Bo Ran, PD, Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu Province, China (e-mail: [email protected]). Copyright r 2014 Wolters Kluwer Health, Inc. All rights reserved.

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been improved compared with that presented during the preoperative period. The implant density of group A (44 ± 4%) was significantly lower than that of group B (55 ± 5%) (P < 0.001). In group A, the main complication was chylothorax (n = 2) and hemopneumothorax (n = 2). In group B, acute intestinal obstruction was observed in 2 patients and pleural effusion was observed in 1 patient. In addition, 12 screws were misplaced (12/403, 3.0%) in group B. Conclusions: In patients with rigid thoracic adolescent idiopathic scoliosis, posterior-only approach with an all-pedicle screw construct could achieve the same curve correction as a combined anterior/posterior spinal fusion by increasing the implant density. However, for scoliosis patients with a high risk of implant complications, anterior release combined with posterior spinal fusion is still recommended. Key Words: thoracoscopy, posterior spinal fusion, all-pedicle screw spinal instrumentation, thoracic adolescent idiopathic scoliosis (J Spinal Disord Tech 2015;28:E454–E459)

T

he anterior release combined with posterior spinal fusion is a standard surgical modality to treat the rigid thoracic adolescent idiopathic scoliosis (T-AIS).1,2 Open anterior surgery combined with posterior surgery causes severe trauma and the patients recover slowly after the surgery, so the thoracoscopic anterior release surgery is advocated by more and more doctors who have been demonstrated to provide a good treatment effect.3,4 Recent studies suggest that rigid T-AIS also can be corrected well by the posterior-only approach with an all-pedicle screw construct.5–7 However, the therapeutic effect is unclear between the thoracoscopic anterior release combined with posterior spinal fusion and the posterior-only approach with an all-pedicle screw construct. The objective of our research is to retrospectively evaluate the safety and effectiveness of a posterior-only approach with J Spinal Disord Tech



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an all-pedicle screw construct in patients with rigid T-AIS in China.

MATERIALS AND METHODS From June 2001 to June 2010, 380 T-AIS patients were admitted to our hospital and 63 patients were enrolled in this study on the basis of the following inclusion criteria: (1) age between 10 and 20 years; (2) thoracic curve Z80 degrees; (3) flexibility r40%; (4) follow-up Z36 months; and (5) intact standing anteroposterior radiograph of the spine. Exclusion criteria were: (1) other types of scoliosis or nonidiopathic scoliosis and (2) patients having a history of undergoing a surgery. Among the 63 patients, 25 cases were treated with the thoracoscopic anterior release combined with posterior spinal fusion (group A) and the remaining 38 cases (23 female and 15 male patients) underwent posterior-only approach with an all-pedicle screw construct (group B). After the induction of general anesthesia, the patients were intubated with a double lumen–cuffed endotracheal tube to allow single-lung ventilation. After the lung on the operated side was deflated, portals (an average of 3, 10 mm) were placed along the midaxillary line. The parietal pleura were incised using electrocautery, and then the intervertebral disks and the upper and lower endplates were excised by curettage to release the spine T4–T12 (5–7 intervertebral spaces). Finally, the debrided disk space was filled with autologous or allogeneic bone. Posterior spinal instrumented fusion was performed after skull traction for 2 weeks. The posterior surgery for both groups was performed on an open orthopedic systems incorporated frame using posterior screw constructs with a 5.5 mm rodbased segmental Cotrel-Dubousset Horizon instrumentation (Medtronic Sofamor Danek, Memphis, TN). All pedicle screws of 3.5–4.0 mm diameter and 35–40 mm length were inserted with a free-hand pedicle screw placement technique. Once the pedicle track was developed and intraosseous borders confirmed, the pedicle was undertapped with a 1.0-mm-smaller diameter tap than that of the intended screw to optimize fixation.6 All surgeries were performed by the same doctors. Intraoperative neurophysiological monitoring, including somatosensory-evoked potentials and motor-evoked potentials, was performed to identify and prevent injury to neurovascular structures during surgery. The patients were followed up at 3 months, 6 months, 1 year, 2 years, and 3 years after the surgery. Standing anteroposterior x-ray examination of the whole spine was carried out preoperatively, postoperatively, and at every follow-up to measure the thoracic curve Cobb angle in the coronal plane, the thoracic kyphosis Cobb angle in the sagittal plane (T5–T12), the thoracic curve flexibility, and the correction ratio. In addition, the scope of anterior release and posterior spinal fusion, implant density (defined as the amount of the screws or hooks/the amount of the fixed segment vertebra pedicles  100%), and the complications that occurred during the postoperative period and at the follow-up visit were recorded. Copyright

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Posterior-only Approach for Rigid Thoracic AIS

All patients were also evaluated using the Scoliosis Research Society-22 questionnaire, which was administered preoperatively and postoperatively. Total scores as well as individual domain scores for pain, selfimage, function, mental health, and satisfaction parameters were calculated and analyzed for each patient. All data were analyzed by SPSS 13.0 statistical analysis software and expressed as mean ± SD. The difference between the 2 groups was compared using the t test and the w2 test. A P-value 0.05). There were 14.3 ± 1.3 vertebral segments posteriorly fixed in group A, whereas 15.8 ± 1.8 vertebral segments were posteriorly fixed in group B. The implant

TABLE 1. Basic Characteristics of the Patients in the Thoracoscopic Anterior Release Combined With the Posterior Spinal Fusion Group Versus Posterior-only Approach With an All-pedicle Screw Construct Group Parameters Sex Male Female Age (y) Risser sign (deg.) Lenke type 1 2 3 4 Follow-up (mo)

Anterior/Posterior (n = 25)

Posterior Only (n = 38)

7 18 13 ± 3.4 3.6 ± 0.6

15 23 14 ± 2.7 3.4 ± 0.5

13 5 5 2 53 ± 5

16 14 4 4 49 ± 6

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P 0.350 0.223 0.265 0.426

0.256

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TABLE 2. Comparison of Therapeutic Outcome Between the Thoracoscopic Anterior Release Combined With the Posterior Spinal Fusion Group Versus Posterior-only Approach With an All-pedicle Screw Construct Group Parameters

Anterior/Posterior (n = 25)

Posterior Only (n = 38)

P

560 930 5 14.3 ± 1.3 44 ± 4

420 780 4 15.8 ± 1.8 55 ± 5

0.126 0.134 0.317 0.351 < 0.001

90 ± 10 56 ± 10 55 ± 5 31 ± 11 35 ± 12 60 ± 12 56 ± 11

88 ± 7 54 ± 12 50 ± 3 28 ± 12 31 ± 11 59 ± 11 31 ± 13

0.22 0.37 0.71 0.40 0.36 0.34 0.58

22 ± 12 27 ± 7 31 ± 12

21 ± 11 28 ± 12 28 ± 10

0.31 0.51 0.48

2 2 0 0 0 0 0 0

0 0 2 1 12 6 4 2

0.001

Operation time Bleeding volume (mL) Length of hospital stay (d) Segmental vertebras Implant density (%) Thoracic curve Cobb angle Preoperative (deg.) Bending (deg.) Fulcrum bending (deg.) Flexibility (%) Postoperative (deg.) Correction ratio (%) Last follow-up (deg.) Thoracic kyphosis Cobb angle Preoperative (deg.) Postoperative (deg.) Last follow-up (deg.) Complications Chylothorax Hemopneumothorax Acute intestinal obstruction Pleural effusion Screws shift Screws penetrating the lateral cortex Screws penetrating the medial cortex Screws penetrating the above cortex

density of group A (44 ± 4%) was significantly lower than that of group B (55 ± 5%) (t = 7.111, P < 0.001). However, no significant differences were observed in the operation time, bleeding volume, and length of hospital stay between the 2 groups. In group A, the preoperative average thoracic curve Cobb angle was 90 ± 10 degrees, which was corrected to 35 ± 12 degrees, postoperatively, and the average thoracic curve Cobb angle at the last follow-up was 56 ± 11 degrees. Thus, the correction ratio was 60 ± 12%. In group B, the preoperative average thoracic curve Cobb angle was 88 ± 7 degrees, which was corrected to 31 ± 11 degrees, postoperatively, and the average thoracic curve Cobb angle at the last follow-up was 31 ± 13 degrees. Thus, the correction ratio was 59 ± 11%. In group A, the preoperative average thoracic kyphosis Cobb angle was 22 ± 12 degrees, which was corrected to 27 ± 7 degrees postoperatively, and the average thoracic kyphosis Cobb angle at the last follow-up was 31 ± 12 degrees. In group B, the preoperative average thoracic

curve Cobb angle was 21 ± 11 degrees, which was corrected to 28 ± 12 degrees postoperatively, and the average thoracic kyphosis Cobb angle at the last follow-up was 28 ± 10 degrees. There were no significant differences in these parameters between the 2 groups (P > 0.05; Table 2). In group A, there were 2 cases showing chylothorax and hemopneumothorax, respectively. In group B, complications included acute intestinal obstruction in 2 patients and pleural effusion in 1 patient who were cured by conservative treatment. A total of 403 screws were inserted in group B, in which 12 screws were misplaced (12/403, 3.0%), including 6 screws penetrating the lateral cortex, 4 screws penetrating the medial cortex (the distance covered by the screws in the spinal canal was 0.2 and 0.3 cm, respectively), and 2 screws penetrating the above cortex. The complications such as nerve injury and vessel injury did not occur after the surgery and during the follow-up visit period (Table 2). In addition, no significant difference in the

TABLE 3. Scoliosis Research Society-22 Patient Questionnaire Scales at Preoperative and Follow-up Anterior/Posterior (n = 25) Domains Function/activity Pain Self-image Mental health Satisfaction with management

Posterior Only (n = 38)

Preoperative

At Last Follow-up

Preoperative

At Last Follow-up

4.1 ± 0.53 3.5 ± 0.68 3.4 ± 0.83 3.3 ± 0.50 2.9 ± 0.75

4.5 ± 0.64* 4.3 ± 0.78* 4.4 ± 0.55* 4.3 ± 0.90* 3.8 ± 0.52*

3.7 ± 0.52 3.4 ± 0.51 3.3 ± 0.69 3.3 ± 0.75 2.8 ± 0.79

4.6 ± 0.50* 4.5 ± 0.61* 4.4 ± 0.45* 4.3 ± 0.54* 4.1 ± 0.72*

*Compared with preoperation, P < 0.05.

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Copyright

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Posterior-only Approach for Rigid Thoracic AIS

FIGURE 1. A 17-year-old girl (Lenke type, 1AN) underwent thoracoscopic anterior release combined with posterior spinal fusion. A, Preoperative anterioposterior x-ray. B, Preoperative lateral x-ray. C, Postoperative anterioposterior x-ray. D, Postoperative lateral x-ray.

Scoliosis Research Society-22 score at the last follow-up was present in the 2 groups, although it had been improved compared with that presented during the preoperative period (Table 3). The typical cases undergoing thoracoscopic anterior release combined with posterior spinal fusion versus posterior-only approach with an all-pedicle screw construct are shown in Figures 1 and 2.

DISCUSSION The anterior release combined with the posterior spinal fusion is a traditional standard means for treating rigid T-AIS. The open thoracotomy can remove the intervertebral disk in direct visualization to release the scoliosis.1,8 However, it may bring about many complications such as pneumonia, pulmonary atelectasis, postoperative serious pain, and a decrease in pulmonary function.9,10 Mack et al11 were the first to implement the thoracoscopic anterior release surgery. Copyright

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They showed that the thoracoscopic anterior release had less influence on the aspiration function and the shoulder activity compared with the thoracotomy and the patients recovered very quickly after the thoracoscopy. Both the animal experiment12 and the controlled clinical trial13 further confirmed that the effect of the thoracoscopic surgery is equivalent to that of thoracotomy in resection of the intervertebral disk and bone graft fusion. Subsequently, the thoracoscopic anterior release along with the fusion of the thoracic spine is demonstrated to be a safe and effective procedure when combined with posterior instrumentation and fusion, which corrects the scoliosis from 80 ± 12 to 36 ± 17 degrees and kyphosis from 88 ± 15 to 60 ± 20 degrees at the latest evaluation.14 In this study, we applied the same procedure and found that the thoracic curve correction ratio was 60 ± 12% after the thoracoscopic anterior release combined with the posterior spinal fusion surgery. However, Longis et al3 reported that thoracoscopic anterior www.jspinaldisorders.com |

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FIGURE 2. A 16-year-old girl (Lenke type, 1AN) underwent posterior-only approach with an all-pedicle screw construct. A, Preoperative anterioposterior x-ray. B, Preoperative lateral x-ray. C, Postoperative anterioposterior x-ray. D, Postoperative lateral x-ray.

release of rigid idiopathic scolioses associated with correction by posterior instrumentation did not improve short-term results in the Cobb angle or frontal or sagittal balance. Thus, further studies are still needed. With the advent of segmental pedicle screw fixation that enables more powerful corrective forces compared with the hook and rod system,15 Suk and colleagues

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suggested that posterior segmental pedicle screw fixation without anterior release also can provide satisfactory deformity correction (from 80 ± 9 degrees, preoperatively, to 27 ± 10 degrees at the most recent followup) for severe scoliosis patients with the flexibility of 45 ± 11%.16 Furthermore, osteotomy and traction17 can be considered in conjunction with posterior pedicle screw Copyright

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instrumentation to acquire better scoliosis correction effect for some rigid thoracic scoliosis with the thoracic curve Cobb angle >80 degrees and the flexibility 1001). Spine. 2008;33: 979–983. 18. Yang S, Jones-Quaidoo SM, Eager M, et al. Right adolescent idiopathic thoracic curve (Lenke 1 A and B): does cost of instrumentation and implant density improve radiographic and cosmetic parameters? Eur Spine J. 2011;20:1039–1047. 19. Quan GM, Gibson MJ. Correction of main thoracic adolescent idiopathic scoliosis using pedicle screw instrumentation: does higher implant density improve correction? Spine. 2010;35:562–567.

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E459

Comparison of Thoracoscopic Anterior Release Combined With Posterior Spinal Fusion Versus Posterior-only Approach With an All-pedicle Screw Construct in the Treatment of Rigid Thoracic Adolescent Idiopathic Scoliosis.

To compare the effect of thoracoscopic anterior release combined with posterior spinal fusion and posterior-only approach with an all-pedicle screw co...
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