Kola Jegede, MD Yongjung J. Kim, MD Zaomin Zheng, MD Gene Cheh, MD, Samuel Cho, MD Sally Pak, RN

大于 90° 的重度脊柱側(cè)凸患者的單純后路椎弓根螺釘內(nèi)固定治療

Kola Jegede, MD Yongjung J. Kim, MD Zaomin Zheng, MD Gene Cheh, MD, Samuel Cho, MD Sally Pak, RN

研究設計回顧性比較研究。目的評估單純后路椎弓根螺釘內(nèi)固定治療側(cè)凸角度＞90° 的重度脊柱畸形的療效和安全性。研究背景對于側(cè)凸角度＞90° 的重度脊柱畸形的標準手術(shù)方式仍存爭議，傳統(tǒng)術(shù)式包括圍手術(shù)期牽引輔助和分期前后路聯(lián)合手術(shù)。方法回顧性分析由同一術(shù)者采取單純后路椎弓根螺釘內(nèi)固定治療的 40 例側(cè)凸角度＞90° 的重度脊柱畸形患者資料，側(cè)凸角度平均為 111.4° ( 91～175 ) °，平均隨訪31 ( 6～60 ) 個月。其中特發(fā)性脊柱側(cè)凸 27 例，先天性 9 例，神經(jīng)肌肉型 3 例，癥狀性 1 例。40 例中，25 例行多節(jié)段 Ponte 截骨術(shù)聯(lián)合后路椎弓根螺釘內(nèi)固定術(shù)，另 15 例則行全脊椎切除聯(lián)合后路椎弓根螺釘內(nèi)固定術(shù)。分析影像學結(jié)果和并發(fā)癥發(fā)生率。結(jié)果影像學結(jié)果表明，單純后路椎弓根螺釘矯形術(shù)可使主彎平均矯正率術(shù)后8 周達 49%，而末次隨訪時為 47% ( P＜0.001 )。總畸形角度 ( 主彎 Cobb’s 角＋最大后凸角 ) 術(shù)前平均為 160°，而術(shù)后 8 周和末次隨訪時，平均矯正率分別為 50% 和 48% ( P＜0.001 )。有 7 例 ( 18% ) 術(shù)中運動誘發(fā)電位( motor evoked potential，MEP ) 消失，而 4 例 ( 10% ) 術(shù)后出現(xiàn)暫時性脊髓神經(jīng)損傷。1 例術(shù)后并發(fā)傷口感染。另1 例術(shù)后 2 年隨訪時發(fā)現(xiàn)內(nèi)植物斷裂，予以觀察隨訪。結(jié)論單純后路椎弓根螺釘內(nèi)固定可有效治療角度＞90°的重度脊柱側(cè)凸，其可避免前路手術(shù)或圍手術(shù)期牽引，達到理想的矯形效果，且無嚴重并發(fā)癥。

脊柱彎曲；脊柱側(cè)凸；手術(shù)后并發(fā)癥；矯形外科手術(shù)

Precis:

40 scoliosis patients with curves greater than 90 degree by posterior only pedicle screw constructs ( POPS ) without perioperative traction or anterior release demonstrated acceptable correction without permanent neurologic defcits.

Key points

.Scoliosis patients with curves ＞ 90 degrees can be managed successfully with posterior only pedicle screw constructs ( POPS ) without perioperative traction or anterior release.

.POPS demonstrated acceptable correction rate and smaller correction loss.

.There were no permanent neurologic deficits despite the18% intraoperative motor evoked potential loss and 10% postoperative transient spinal cord defcits.

Introduction

Spinal instrumentation and fusion in scoliotic curves greater than 70 degrees created a significant challenge for spine surgeons. Traditionally combined anterior and posterior spinal fusions were recommended for those larger curves[1]. Several recent studies have reported successful posterior only instrumented fusion for adolescent idiopathic scoliosis ( AIS ) with major Cobb’s angle between 70 to 100 degree[2-5].

Although various modern instrumentation systems and surgical techniques are currently available, the spinal reconstructive surgery for severe scoliosis ＞ 90 degree curves has remained challenging. Factors such as the severity of deformity, less flexible curve, poor pulmonary function, potential pseudarthrosis, and neurological complications contribute to the level of difficulty[6-10]. Traditionally surgical options to correct severe spinal deformities include anterior release and posterior instrumentation with or without perioperative traction, and various spinal osteotomies, such as Ponte osteotomy or posterior vertebral column resection ( PVCR )[11-20].

To the best of our knowledge, no reports have demonstrated the effcacy of the posterior only pedicle screw constructs for severe idiopathic or congenital scoliosis curves greater than 90 degrees. The purpose of this study was to verify the efficacy and safety of posterior only pedicle screw constructs in idiopathic and congenital scoliosis curvatures who present with curves greater than 90 degrees with respect to the radiographic outcomes and clinical complications.

Materials and Method

Forty scoliosis patients ( 7 males and 33 females ) with greater than 90 degree curves ( mean 111.4°, range 91° to 175° ) with an average 2.51-year followup ( range six months to five years ) who underwent posterior only pedicle screw instrumentation and fusion since 2009 were retrospectively analyzed. All surgeries were performed by one senior author ( YJK ). Clinical and radiographic data collection was performed.

Radiographic Measurements

The preoperative radiographic evaluation for all patients included a 32- or 14- inch posteroanterior and lateral radiograph taken with the patient standing or supine depending on ambulatory status. Only one patient underwent supine radiographs ( non-ambulator with neuromuscular scoliosis ). Postoperative radiographs consisted of standing or sitting posteroanterior and lateral radiographs taken on a 32- or 14- inch cassette. Radiographic analysis on the coronal plane included the major curve Cobb’s angle, global coronal balance ( translation of the C7plumb line from the center sacral vertical line ), pelvic obliquity, and clavicle angle on the standing / sitting posteroanterior radiograph. Radiographic analysis also included preoperative flexibility on side-benders compared to the standing posteroanterior radiograph. On the sagittal imaging, we included thoracic ( T5-12) and lumbar ( T12-S1) sagittal Cobb’s angles as well as maximal kyphosis sagittal Cobb’s angles. Positive values were used to denotekyphosis. Negative values were used to indicate lordosis. All radiographic measurements were performed on the preoperative, 6-8 weeks postoperative and ultimate postoperative radiographs by a single reviewer.

Clinical complications

Long-term complications including pseudarthrosis, coronal or sagittal imbalance, and implant failure such as implant breakage or dislodgement were investigated on plain radiographs. Pseudarthrosis was defined as a demonstration of greater than 10 degree correction loss in major Cobb’s angle and implant failure. Perioperative and delayed postoperative neurological defcits as well as postoperative wound infection were investigated using medical records.

Operative Procedure

All 40 patients underwent posterior only pedicle screw instrumentation and fusion with autogenous rib bone graft ( n=20 after thoracoplasty or PVCR ) or local bone graft ( n=40 ) or iliac crest bone graft ( n=4 ).

All pedicle screws were inserted using free hand technique as described[21]. The pre-contoured concave rod was usually placed first. The convex rod or temporary short convex rod were occasionally placed first for apical correction if the patient was hyperkyphotic alignment on the sagittal plane. Apical correction was obtained by utilizing cantilever forces, in-situ rod contouring technique, and appropriate compression / distraction forces. Bilateral iliac screws were used for all patients necessitating distal fusion down to the sacrum.

Five patients had thoracoplasties. Fifteen patients had posterior vertebral column resection ( PVCR ) around the apex of the curve and 25 patients had multiple Ponte osteotomies on the apical levels[18,22]. Thoracolumbosacral orthosis was used in all patients after surgery and the mean duration of the brace was 3 months.

Statistical Analysis

The data was analyzed with use of the StatView-J 5.0 ( Abacus Concepts, Berkeley, CA ). The distributions of the variables were given as the means, standard deviations, and ranges. Student T test and Chisquare test were used. P ＜ 0.05 was considered to be statistically signifcant.

Results

Demographics ( Table 1 )

Average age at surgery was 21.5 years ( range, 9 to 71 years ). 33 patients were women and seven men. Etiologic diagnoses were: 27 idiopathic, nine congenital, one muscular dystrophy, one paralytic due to residual polio, one spastic scoliosis with cerebral palsy and one dysplastic scoliosis with neurofbromatosis. 14 patients had thoracolumbar / lumbar major curve and 26 patients had thoracic major curve. 39 patients were ambulators and 1 patient was not able to maintain a seated position pre- and post operatively due to severe cerebral palsy.

Radiographic Results ( Table 2 )

The distribution of the major Cobb’s angle was; 10 patients of 91° to 1000, 18 patients of 101° to 119°, six patients of 120° to 129° and six patients of 130° to 175°. Major curve Cobb’s angle was corrected from ( 111 ± 18.4 ) ° ( fexibility: 19% ) preoperatively to 58° at 6 weeks post operation, and ( 60 ± 23.2 ) ° ( correction rate: 47% ) at the ultimate follow-up ( P ＜ 0.001 ). The average amount of correction loss was 2° at the ultimate follow-up. The average sagittal T5-12angle was 70° preoperatively, and 34° at the ultimate follow-up ( P ＜ 0.001 ). The average sagittal T12-S1angle was -84° preoperatively and -64° at the ultimate follow-up ( P ＜0.001 ). 17 patients had a signifcant regional kyphosis of 119 degree ( 60 to 165 degree ). The maximal kyphosis sagittal angle among 17 patients with severe regional kyphosis was 119° preoperatively, and 52° at the ultimate follow-up ( P ＜ 0.001 ). The distribution of the total deformity angle defined by addition of major curve Cobb’s angle and maximal kyphosis was; 24 patients of 91° to 150°, 12 patients of 151° to 250°, and four patients of 251° to 300°. Total deformity angle was 160° preoperatively, and 80° at the ultimate followup respectively ( P ＜ 0.001 ).

Complications ( Table 3 )

There were seven patients ( 18.0% ) whodemonstratedMEP( motor evoked potential ) loss intraoperatively. Intraoperative MEP loss were related to Ponte osteotomy or PVCR after pedicle screw placement had occured. Five out of 7 patients with intraoperative MEP loss had PVCR. 33 % ( Five out of 15 ) of patients with PVCR showed intraoperative MEP loss. Two of 25 patients with multiple Ponte osteotomies showed intraoperative MEP loss ( P = 0.08 ). Three of 7 patients with intraoperative MEP loss had complete recovery of motor evoked potential following rod fixation and compression and demonstrated no motor weakness postoperatively. Ten percent of total patients ( 4 out of 7 patients with intraoperative MEP loss ) showed persistent MEP loss despite the enough decompression, rod fixation, and appropriate compression and either paraplegia ( n = 2 ), monoplegia ( n = 1 ), and incomplete cauda equine syndrome ( n = 1 ) postoperatively. Four out of 15 patients with PVCR showed postoperative neurologic defcits. None of the 25 patients with multiple Ponte osteotomies showed postoperative motor weakness ( P = 0.0149 ). The patients with postoperative monoplegia started to move the affected extremity on POD #1. The two paraplegic patients began to move toes on bilateral feet on POD #2. All patients with neurological compromise postoperatively of them including the incomplete cauda equina syndrome demonstrated near complete motor recovery in 1 month.

One patient had a postoperative infection, which was eliminated with irrigation and debridement. Another subject had a unilateral broken rod detected 2 years post operation treated without revision surgery.

Discussion

The consecutive series of patients undergoing surgery for severe scoliosis ＞ 90 degrees performed by one senior surgeon is a potential limitation of the study. It is possible that the results somewhat refect the learning curve of the senior surgeon during the study period. The position of the pedicle screws was not routinely checked with computed tomography ( CT ) scans. Malposition of pedicle screws might be reported only with neurologic complications intraoperatively and postoperatively. No neurologic symptoms were identifed with pedicle screw fxation.

There is a paucity of data focusing on severe idiopathic or congenital scoliosis ＞ 90 degrees. Watanabe et al. observed 67 patients with 43 neuromuscular scoliosis and only 10 patients with posterior only pedicle screw constructs ( POPS )[11]. Hamzaoglu et al. reported severe idiopathic scoliosis in 15 consecutive patients[14]. This current study currently demonstrated the largest with 36 idiopathic or congenital scoliosis with curves ＞ 90 degrees.

Fig.1 16 year-old-girl with severe idiopathic scoliosis. Posterior only pedicle screw construct at T2-L3with multiple Ponte osteotomies and thoracoplasty. 125° major Cobb’s angle preoperatively to 75° and 67° thoracic kyphosis at T5-T12to 25° with excellent global coronal and sagittal balance

Hamzaoglu et al. reported a mean of 51% correction of severe idiopathic scoliosis in 15 consecutive patients who underwent wide posterior facet joint resections combined with intraoperative halo-femoral traction up to 50% of the body weight. Watanabe et al. showed major curve Cobb’s correction of 67%. His patient population demonstrated more flexible curves of 35%. Six of 16 patients underwent anterior spinal fusion prior to posterior construct. This currentstudy demonstrated that posterior only all pedicle screw instrumentation and fusions have been not only effective in acceptable deformity correction ( 50% ) without pseudarthrosis, but also safe without permanent neurologic deficits even for the scoliosis curvatures greater than 90 degrees.

Fig.2 71 year-old-woman with severe idiopathic scoliosis. Posterior only pedicle screw construct at T9-Pelvis with PVCR and prophylactic vertebroplasty at T8and T9. Total deformity of 218 degree ( 103° major Cobb’s + 115° thoracolumbar kyphosis ) preoperatively to 57° ( 57° major Cobb’s + 0° thoracolumbar kyphosis ) after surgery immediately at the ultimate follow-up. Excellent global coronal and sagittal balance postoperatively

Tab.1 Characteristics of the patients (±s, n = 40 )

Tab.1 Characteristics of the patients (±s, n = 40 )

Diagnosis Idiopathic Scoliosis n = 27 Congenital kyphoscoliosis n = 9 Muscular dystrophy n = 1 Post Poliomyelitis n = 1 Neurofbromatosis n = 1 CP scoliosis n = 1 Operation Average age at Op: 21.5 ± 13.1 years ( range 9.1-71 years ) Opertion time: 6.95 ± 1.5 hours ( 5 to 13 hours ) Operative blood loss 2011 ± 1740 ( 850 to 10 000 cc ) Number of fused vertebrae 13.1 ± 2.6 ( 7-17 ) Gender 33 women and 7 men

Tab.2 Radiographic results (±s, n = 40 )

Tab.2 Radiographic results (±s, n = 40 )

Preop Ultimate Follow-up P-value Major Cobb’s Changes 111° ± 18.4° ( fexibility: 19% ) 60° ± 23.2° ( 47% ) ＜0.001 Thoracic kyphosis ( T5-T12) 70° ± 10.4° 34° ± 13.4° ＜0.001 Maximal kyphosis ( n = 17 ) 119° ± 31.0° 52° ± 31.0° ＜0.001 Total Deformity Major Cobb’s + Maximal kyphosis 160° ± 67.1° 80° ± 41.7° ＜0.001 Major Cobb’s angles 91° to 100° n = 10, 101° to 119° n = 18, 120° to 129° n = 6, 130° to 175° n = 6 Total Deformity 91° to 150° n = 24, 151° to 250° n = 12, 251° to 300° n = 4

Tab.3 Complications

Seven of 40 patients ( 18% ) demonstrated intraoperative MEP loss after Ponte osteotomies or PVCR following pedicle screw placement. Of note, large curves ＞ 100° carry about a 10% risk of neurological compromise with curve correction[6]. Pedicle screws placement did not show the risk of MEP loss for severe scoliosis ＞ 90 degrees in spite of the theoretically higher chance of the neurological complications. Three out of 7 patients with intraoperative MEP loss showed complete recovery after stabilization and spinal cord shortening intraoperatively. 4 ( 10% of total patients ) of 7 patients with intraoperative MEP loss showed persistent MEP loss and postoperative neurologic defcit. All 4 patients had a megadose steroid treatment. All of them had complete motor recovery within 1 month. All four patients had PVCR ( 4 / 15 = 27% ). Jarvis et al[23]reported 5 / 28 patients had immediately postoperative had neurologic deficits even though there was no permanent defcits. However, Suk et al[17]and Lenke et al[19]reported permanent spinal cord defcit after PVCR even though the prevalence is very low. Xie et al also showed 6 / 76 patients with changes in neurologic status postoperatively[24]. Due to the potential high risk of neurologic compromise, PVCR should be used as the last surgical option. Intraspinal and brain stem anomalies ( × 9 ), preexisting neurologic dysfunction ( × 8 ),number of segmental vessels ligated ( × 7 ), higher level of vertebral column resected ( × 6 ), scoliosis associated with thoracic hyperkyphosis ( × 5 ), Cobb’s angle at the main curve at the coronal plane ( × 4 ), and location of apex at main curve ( × 3 ) are known to the risk factors of neurologic defcits after PVCR[24].

Conclusion

Scoliosis patient with curves ＞ 90 degrees can be managed successfully by posterior-only pedicle screw constructs ( POPS ). This approach avoids the need for anterior surgical procedures or perioperative traction while achieving acceptable correction safely without signifcant complication.

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( 本文編輯：王萌 張倩 )

Posterior only pedicle screw construct for the treatment of scoliotic curves greater than 90 degrees

Kola Jegede, Yongjung J. Kim, Zaomin Zheng, Gene Cheh, Samuel Cho, Sally Pak. Department of Orthopedic Surgery, Columbia University College of the Physicians and Surgeons, New York, USA

Study designA retrospective comparative study.ObjectiveTo assess the effcacy and safety of posterior only pedicle screw construct ( POPS ) for the treatment of scoliotic curves ＞ 90 degrees using radiographic outcomes and various clinical outcomes.Summary of Background DataA paucity of data exists regarding standardized surgical options for severe scoliotic curvatures ＞ 90°. Perioperative traction or staged anterior and posterior operations were the traditional surgical options.MethodsA total of 40 consecutive scoliosis patients with curves ＞ 90° ( average 111.4°; range 91°-175° ) with an ( average follow-up of 31 months; range 6-60 months ) who underwent spinal instrumented fusion with posterior only pedicle screw constructs performed by a single surgeon were analyzed. Diagnoses included idiopathic scoliosis ( n=27 ), congenital ( n=9 ), neuromuscular ( n=3 ), and syndromic ( n= 1 ). In total, 25 patients were treated with posterior only pedicle screw constructs with multiple Ponte ostotomies while the other 15 patients with posterior vertebral column resection. Radiographic examinations and complications were analyzed.ResultsRadiographic outcomes demonstrated an average major curve correction of 49 % and 47% at eight weeks post operation and final follow-up respectively ( P＜0.001 ). Total deformity angle, major Cobb’s angle + maximal kyphosis with an average of 160 degrees preoperatively, showed an average correction of 50 % and 48% at eight weeks post operation and fnal follow-up respectively ( P＜0.001 ). There were seven cases ( 18% ) of intraoperativeMEP( motor evoked potential ) loss and four patients ( 10% ) with transient spinal cord defcit. One patient developed postoperative infection. Another patient had a unilateral broken rod in two years follow-up which was treated with observation.ConclusionsScoliosis patients with curve ＞ 90 degree can be managed successfully by posterior only pedicle screw construct ( POPS ). POPS avoids the need for anterior surgical procedures or perioperativetraction while achieving acceptable correction safely without signifcant complication.

Spinal curvatures; Scoliosis; Postoperative complications; Orthopedic procedures

10.3969/j.issn.2095-252X.2014.12.003

：R682.3

2014-09-09 )

Authors working place: NY 10032, New York, Investigation performed Columbia University College of the physicians and Surgeons, USA Correspondence Author: Yongjung “Jay” Kim MD, Email: yk2299@columbia.edu