Thoracoscopic anterior instrumentation and fusion for idiopathic scoliosis

Thoracoscopically assisted surgery is a new approach to access the anterior spine to perform biopsies, anterior releases, diskectomies, and anterior instrumentation and fusion for idiopathic thoracic scoliosis. This approach compromises the chest wall less than an open thoracotomy does because it uses several small portal incisions. It has been suggested that this approach allows fusion of fewer motion segments and better correction of curvature than does posterior spinal fusion and instrumentation. The technique, which is still evolving, is technically demanding, requiring advanced training and special instrumentation and anesthesia techniques.     

特发性脊柱侧凸的前路矫形手术

目的评价前路矫形手术对特发性脊柱侧凸的治疗效果。方法回顾性分析术后随访时间超过1年的特发性脊柱侧凸34例,男5例,女29例;年龄8～17.5岁,平均15.7岁。侧凸类型包括PUMCⅠa型1例、Ⅰb型8例、Ⅰc型6例、Ⅱc1型4例、Ⅱd1型15例。采用前路三维矫形手术,内固定器械包括TSRH16例、MossMiami8例、CDH10例。术前、术后及随访时摄X线片,测量冠状面及矢状面Cobb角、躯干偏移、顶椎及下融合椎的旋转度、下融合椎与骶骨夹角,并观察有无假关节形成。结果全部病例随访12～63个月,平均21个月。术中出血量200～1200ml,平均255ml。融合3～7节椎体,平均4.42节。融合弯冠状面畸形矫正率平均为73.4%,矢状面手术前后Cobb角差异无显著性。7例胸腰段或腰椎后凸患者术前后凸平均11.9°,术后矫正为前凸6.8°。19例双弯患者术后上弯冠状面自动矫正率为39.5%(P<0.01);融合弯顶椎旋转改善率32%(P<0.01),下融合椎旋转亦有明显改善(P<0.05),上弯顶椎旋转无明显改善。凸侧Bending像融合弯Cobb角与术后比较差异有显著性(P<0.01)。单弯(PUMCⅠb型、Ⅰc型)者术后即刻躯干偏移增加7.3mm,1年后较术前改善7.5mm;双弯者术后躯干偏移持续改善。凹侧Bending像下融合椎与骶骨的夹角与术后比较差异无显著性。结论前路矫形融合术具有较强的冠状面     

Posterior instrumentation and fusion for progressive idiopathic scoliosis

Objectives  

Prevention of progression of an idiopathic scoliosis. Structural improvement of the spinal column and correction of the trunk deformity.     

Hybrid instrumentation for correction of adolescent idiopathic scoliosis

New technology and instrumentation techniques are continually entering the spine field, leaving the scoliosis surgeon with a wide variety of options for the treatment of adolescent idiopathic scoliosis. All-screw constructs are currently the most popular. However, they remain controversial because of possible complications, and also because they have been associated with a decrease in thoracic kyphosis, not observed with hybrid instrumentation. The aim of the present study was to evaluate a hybrid construct: hooks and wires proximally, but pedicle screws distally. Forty-three patients with a minimum 2-year follow-up were included. The mean preoperative Cobb angle of the major curve was 60.85 degrees +/- 21 degrees. At the final evaluation it was reduced to 28.44 degrees +/- 11.9 degrees (mean correction 53.3%, p < 0.0001). The mean translation of the apical vertebra was corrected from -19.13 +/- 49 mm to -9.42 +/- 28.9 mm. The average thoracic kyphosis improved from 24 degrees +/- 14.3 degrees preoperatively to 30.7 degrees +/- 7.1 degrees, representing a mean correction of 28%. Kyphosis at the T10-L2 level was within normal values in all patients at the final evaluation. Complications included one superficial infection, one implant removal due to late onset wound infection, and 2 revisions to extend the fusion more distally. In other words, operative treatment with hybrid instrumentation yielded satisfactory results, with less risk of neurological damage. An excellent outcome in all planes could be safely achieved and maintained for a minimum of 2 years. CONCLUSION: why use an expensive all-screw construct, knowing that a hybrid construct is kyphosis sparing, cheaper, safer and more resistant to pull-out?     

Selection of fusion levels for posterior instrumentation and fusion in idiopathic scoliosis

The selection of fusion levels in idiopathic scoliosis is an important decision. Careful analysis of curve patterns and preoperative planning will help with the fusion and in the selection of fusion levels. The goal of treatment is to achieve a stable, balanced spine and yet maintain as much flexibility in the lumbar spine as possible. This article helps establish guidelines for curve analysis and the selection of fusion levels.     

Early ambulation following spinal fusion and Harrington instrumentation in idiopathic scoliosis.

Eighty-six patients with idiopathic scoliosis managed by Harrington instrumentation and spinal arthrodesis were ambulated 10 days following surgery. Preoperative reduction of the curves was obtained by Cotrel traction and modified Cotrel localizer cast. Patients were kept immobilized in plaster cast for 7 months following operation. No significant loss of correction was found in these patients ambulated early as compared to a previous group kept recumbent for 3 to 6 months and reported by the authors (DBL). The only exception to this was a patient with double structural curve patterns. A successful surgical program for most cases of idiopathic scoliosis included: (1) Preoperative reduction and balancing of curves by non-skeletal traction and/or correction body cast; (2) Meticulous spinal arthrodesis and employment of Harrington distraction internal fixation; (3) Autogenous iliac bone graft; (4) Ambulation at two weeks following surgery in a well fitting body cast and removal of this cast after 7 months. Deep infection rate was 1 per cent without the use of routine prophylatic antibiotics. One neurological complication resulted from the use of a single distraction rod bridging two curves where the rod was not prebent to allow for kyphosis. There were no pseudarthroses. The average follow-up was 28 months with a range of 18-39 months.     

Criteria for selective fusion in idiopathic scoliosis using Cotrel-Dubousset instrumentation.

Spinal decompensation after Cotrel-Dubousset (C-D) instrumentation in the King type II curve pattern has become a recognized complication secondary to progression of the unfused lumbar curve. Twenty-three patients with type II curves who underwent selective thoracic fusion according to the guidelines established by King et al. were reviewed. Mean follow-up was 19.5 months. Lumbar curves greater than 45 degrees associated with a low flexibility index were significantly more likely to develop postoperative progression of the uninstrumented lumbar curve with resultant spinal decompensation, suggesting that in these curves the King criteria for selective thoracic fusion may not be appropriate.     

Comparative analysis of pedicle screw and hook instrumentation in posterior correction and fusion of idiopathic thoracic scoliosis

Posterior correction and fusion with segmental hook instrumentation represent the gold standard in the surgical treatment of progressive idiopathic thoracic scoliosis. However, there is a debate over whether pedicle screws are safe in scoliosis surgery and whether their usage might enable a better curve correction and a shorter fusion length. The details of curve correction, fusion length and complication rate of 99 patients with idiopathic thoracic scoliosis treated with either hook or pedicle screw instrumentation were analyzed. Forty-nine patients had been operated with the Cotrel-Dubousset system using hooks exclusively ("hook group"). Fifty patients had been operated with either a combination of pedicle screws in the lumbar and lower thoracic and hooks in the upper thoracic spine or exclusive pedicle screw instrumentation using the Münster Posterior Double Rod System ("screw group"). The preoperative Cobb angle averaged 61.3 degrees (range 40 degrees-84 degrees ) in the hook group and 62.5 degrees (range 43 degrees-94 degrees ) in the screw group. Average primary curve correction was 51.7% in the hook group and 55.8% in the screw group ( P>0.05). However, at follow-up (2-12 years later) primary curve correction was significantly greater ( P=0.001) in the screw group (at 50.1%) compared to the hook group (at 41.1%). Secondary lumbar curve correction was significantly greater ( P=0.04) in the screw group (54.9%) compared to the hook group (46.9%). Correction of the apical vertebral rotation according to Perdriolle was minimal in both groups. Apical vertebral translation was corrected by 42.0% in the hook group and 55.6% in the screw group ( P=0.008). Correction of the tilt of the lowest instrumented vertebra averaged 48.1% in the hook group and 66.2% in the screw group ( P=0.0004). There were no differences concerning correction of the sagittal plane deformity between the two groups. Fusion length was, on average, 0.6 segments shorter in the screw group compared to the hook group ( P=0.03). With pedicle screws, the lowest instrumented vertebra was usually one below the lower end vertebra, whereas in the hook group it was between one and two vertebrae below the lower end vertebra. Both operative time and intraoperative blood loss were significantly higher in the hook group ( P<0.0001). One pedicle screw at T5 was exchanged due to the direct proximity to the aorta. There were no neurologic complications related to pedicle screw instrumentation. Pedicle screw instrumentation alone or in combination with proximal hook instrumentation offers a significantly better primary and secondary curve correction in idiopathic thoracic scoliosis and enables a significantly shorter fusion length.     

Posterior spinal fusion and instrumentation in the treatment of adolescent idiopathic scoliosis.

Three hundred and nineteen patients with adolescent idiopathic scoliosis were treated by posterior spinal fusion over an eight year period. The changes in preoperative correction and surgical techniques are reviewed. The anaesthetic technique using induced hypotension and the postoperative routine are described. The amount of deformity and its correction at operation and postoperatively is discussed by reference to Cobb angles. The early and late complications are reviewed.     

Results of Harrington instrumentation and fusion in the adult idiopathic scoliosis patient.

Between January 1961 and December 1972, 132 patients over twenty years old with idiopathic scoliosis were surgically treated using Harrington instrumentation and fusion techniques. All patients were seen by us because of curve magnitude or symptoms secondary to scoliosis. The average correction obtained at operation was 48 per cent. Twenty-four patients had early complications. Fifty-two had late complications, the most frequent of which was pseudarthrosis. The majority of patients had significant improvement in symptoms as a result of surgical correction and stabilization.     

Apical instrumentation alters the rotational correction in adolescent idiopathic scoliosis

The aim of this study was to retrospectively evaluate the effect of apical vertebral instrumentation in the axial plane in the surgical treatment of idiopathic scoliosis. Seventy-six consecutive patients with King type II idiopathic scoliosis, treated with posterior spinal instrumentation, were included in the study. The mean age of the patients was 14.5 years (range 10-18 years), and the mean follow-up was 49 (range 28-74) months. Preoperative radiological evaluation was performed with postero-anterior, lateral, traction and side-bending radiographs. Vertebral rotation was measured with a Perdriolle torsion meter. Patients were retrospectively divided into two groups according to the presence of apical vertebra instrumentation. Group 1 consisted of 43 patients in whom the upper and lower neutral and intermediate vertebrae of thoracic curves had been instrumented on the concave side. Group 2 consisted of 33 patients who had received instrumentation of the apical vertebra on the concave side in addition to the instrumentation configuration of group 1. Posterior fusion was added in all patients. Cobb and Perdriolle measurements were compared between the two groups preoperatively and at the last follow-up. Preoperative age and gender distribution, Cobb angle and rotational measurements, and correction ratios on side-bending films were similar in the two groups. Although the differences between the two groups in preoperative mean values of both Cobb angle and apical rotation were not statistically significant (P>0.05), mean values of apical rotation were significantly different postoperatively (P<0.05). At the same time, apical derotation ratios differed significantly between the two groups (P=0.000). We conclude that instrumentation of the apical vertebra provides better derotation at the apex.     

The results of anterior fusion and Cotrel-Dubousset-Hopf instrumentation in idiopathic scoliosis

Anterior instrumentation for the correction of scoliotic curves has recently been gaining in popularity. The problems of high mortality and morbidity that were associated with the employment of anterior instrumentation in the first years it was used have now been overcome. Efforts are now being concentrated on increasing the correction rates in the frontal plane and decreasing the kyphotic effect in the sagittal plane. The anterior Cotrel-Dubousset-Hopf (CDH) system is a recently developed instrumentation that has been claimed to decrease the kyphotic effect through the use of double rods. This study aimed to investigate the impact of the anterior CDH system on idiopathic scoliotic curves in frontal and sagittal planes. To this end, 26 idiopathic scoliosis patients treated with the CDH system were followed for a mean period of 32.8 ± 5.3 months. In the frontal plane, Cobb angles of major and secondary curves were measured, and postoperative and final correction rates determined. In the sagittal plane, sagittal contours of both the instrumented region and the thoracic and lumbar regions were measured, and their preoperative, postoperative and final control values were determined. In addition to clinical examination, lateral trunk shift (LT), shift of head (SH) and shift of stable vertebra (SS) were measured in vertebral units (VU), on the preoperative and postoperative radiographs in order to evaluate the effect of the system on trunk balance. It was established that in patients with single flexible thoracolumbar and lumbar curves and those with rigid thoracic curves, the correction rates obtained in the frontal plane were respectively 79.4 ± 14.8%, 68.0 ± 9.4% and 61.5 ± 8.0%, with statistical significance. Their final corrections at the last control were 76.3 ± 17.4%, 56.9 ± 9.1% and 52.3 ± 8.3%, respectively. Although the corrections in the lumbar rigid curves were relatively low, they were still statistically significant. Taking all the patients together, the mean preoperative Cobb angle of the major curves of 67.2°± 20.2° improved to a mean of 28.6°± 21.0°, which was a statistically significant difference (P < 0.05), giving a mean correction rate of 61.2 ± 20.3%. The mean correction loss of major curves in the frontal plane in all patients was 6.0°± 3.8° and the mean final correction rate was 52.6 ± 23.2%. In the sagittal plane, there was a favorable kyphotic effect on the thoracic region of patients with hypokyphosis and lordosis pattern, whilst in patients with kyphotic pattern, this effect was minimal. In patients with a single flexible lumbar curve, kyphotic effect was not observed except in two patients. In these two patients, it was thought that excessive compression force may have been used. As to the patients with a rigid lumbar curve, there was a slight decrease in lumbar lordosis. No postoperative complaints were made about imbalance, and the mean overall correction in LT values was 60.1 ± 21.7%. While preoperatively, the SH and SS values of all patients were over 0.5 VU, postoperatively, 12 patients (46.2%) were completely balanced (SH = 0 VU, SS = 0 VU) and 8 patients (30.8%) were balanced (0 VU < SH and SS < 0.5 VU). The remaining six patients, whose balance values were corrected with statistical significance but were still over 0.5 VU, were found to be the ones with rigid lumbar curves. Implant failure and systemic complications were not noted in the follow-up period. In view of these findings, it was determined that CDH instrumentation achieves significant correction rates in the frontal and sagittal planes, particularly in single flexible lumbar, thoracolumbar and thoracic rigid curves. It was found that the kyphotic effect was minimized with a double rod system. Significant clinical and radiological corrections were achieved in balance values, without any imbalance and decompensation problems. Received: 27 April 1999 Revised: 13 April 2000 Accepted: 2 May 2000     

Adult idiopathic scoliosis treated by posterior spinal fusion and Harrington instrumentation

Ninety-one patients with idiopathic scoliosis, who underwent posterior spinal fusion and instrumentation from January 1977 to December 1982, were reviewed. All patients were 20 years or older at the time of surgery and none had undergone a prior surgical procedure. Indications for surgery included pain, progressive deformity, and pulmonary symptoms. All patients had a posterior spinal fusion with Harrington instrumentation and autogenous iliac bone graft, with the addition of segmental wiring in only eight. No patient had an anterior fusion or fusion to the sacrum. Follow-up averaged 3.5 years (range: 2-7 years). The average correction at the time of surgery was 38%, and 32% at the time of last follow-up. Seventy-nine percent of the patients reported complete relief of the symptom(s) for which they had surgery. There were 34 complications in 30 (33%) patients. Pseudarthrosis occurred in 14 (15%), requiring 15 additional procedures to achieve a solid arthrodesis. Urinary tract infection occurred in 8 (9%) patients and Harrington hook dislodgement in 5 (5%). One patient sustained a partial paraparesis with recovery to a minimal deficit. No deaths occurred. Although largely successful, posterior fusion with Harrington instrumentation for adult scoliosis has a significant incidence of pseudarthrosis and instrumentation problems.     

Anterior versus posterior instrumentation for the correction of thoracic idiopathic scoliosis

Traditionally, thoracic idiopathic scoliosis has been treated by posterior instrumentation and fusion, which is still the gold standard. However, anterior instrumentation and fusion became a viable option for these patients during the 1990s and are gaining acceptance. Currently, controversy still exists regarding the indications for the anterior approach, and the benefits of the anterior versus posterior approach remain unsettled. Therefore, this topic was considered ideal for noted experts on both sides to present their opinions, with Dr. Harry Shufflebarger promoting posterior instrumentation and Dr. Randy Betz encouraging anterior instrumentation. The efforts of these two outstanding and dedicated scoliosis specialists to educate the readers of Spine regarding their viewpoints are appreciated.     

Thoracic curve correction after posterior fusion and instrumentation of structural lumbar curves in patients with adolescent idiopathic scoliosis

Introduction

Spontaneous thoracic curve correction may occur following selective anterior spinal fusion in patients with adolescent idiopathic scoliosis (AIS). However, a few reports have described outcomes in patients following selective posterior fusion. The aim of this retrospective study was to assess curve correction in AIS patients with major lumbar curves and secondary thoracic curves after selective posterior fusion of the major curve.

Methods

The records of 42 AIS patients with major lumbar and minor thoracic curves who had received selective posterior lumbar fusion with segmental pedicle screw fixation were examined. Preoperative and follow-up radiographs were examined and the following were determined: curve flexibility, Cobb angle measurements of the major and minor curves, thoracolumbar/lumbar and thoracic Cobb measurements. Also, thoracolumbar/lumbar to thoracic Cobb ratios were determined. Minimum follow-up was 2?years. Patients were compared with respect to whether final thoracic curve improvement was (group A) or was not (group B) apparent. Improvement was indicated by a final thoracic curve that was less than the preoperative thoracic curve.

Results

Thoracic curve improvement was apparent in 32 of 42 patients after surgery. The mean preoperative thoracic curve in group A was 22.5° and 15.0° at follow-up, while corresponding values in group B were 35.0° and 39.8°. There were no cases in group A and eight cases in group B in which the preoperative thoracic curve was >30°. All patients in group B had preoperative thoracic curves on lateral bending >20°. Thoracic curvature at final follow-up was strongly correlated with preoperative thoracic curvature (r?=?0.911) and thoracic curvature on lateral bending (r?=?0.948).

Conclusions

Selective posterior fusion with segmental pedicle screw fixation in patients with major lumbar AIS resulted in curve correction in the majority of cases. Preoperative thoracic curvature and thoracic curvature on lateral bending were strongly correlated with the final thoracic curvature.     

Cotrel-Dubousset instrumentation for adolescent idiopathic scoliosis.

We evaluated the results of segmental fixation of the spine with Cotrel-Dubousset instrumentation in ninety-five patients who had adolescent idiopathic scoliosis. The instrumentation was used in an attempt to achieve three-dimensional correction of the scoliosis, maintain lumbar lordosis, create thoracic kyphosis, and avoid the need for a postoperative cast or brace. The patients were followed for twenty-four to sixty-four months (average, thirty-five months). Cotrel-Dubousset instrumentation provided an average correction of the coronal curve of 48 per cent at the time of the most recent follow-up. The normal sagittal curves at the thoracolumbar junction and in the lumbar spine were maintained, and the thoracic kyphosis was increased slightly (average, +7 degrees). Apical translation improved an average of 60 per cent, and apical rotation improved an average of 11 per cent. Forced vital capacity improved an average of 21 per cent, and the one-second forced expiratory volume improved an average of 18 per cent. There were no major neurological deficits. A symptomatic pseudarthrosis developed in one patient. Postoperatively, decompensation of the spine developed in five of the first twenty-six patients who had a Type-II or Type-III curve. This complication was avoided in the last twenty-four patients who had a Type-II or Type-III curve by means of a stricter adherence to the definition of a Type-II curve, and reversal of the bend of the rod and the hooks between the caudal neutral and stable vertebrae. The major advantages of Cotrel-Dubousset instrumentation are the stable fixation that is achieved and the preservation of segmental lumbar lordosis.     

Comparison of anterior and posterior instrumentation for correction of adolescent thoracic idiopathic scoliosis

STUDY DESIGN: This was a prospective study of two cohort groups of patients (one group receiving anterior instrumentation and the other posterior instrumentation) receiving treatment for thoracic idiopathic scoliosis. OBJECTIVE: To present the 2-year postoperative results of a prospective multicenter study comparing the use of anterior instrumentation with that of posterior multisegmented hook instrumentation for the correction of adolescent thoracic idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Despite reports of satisfactory results, problems have been reported with posterior systems, including worsening of the lumbar curve after surgery and failure to correct hypokyphosis. Theoretically, the advantages of anterior instrumentation include prevention of lumbar curve decompensation by shortening the convexity of the thoracic curve. In addition, by removing the disc, better correction of thoracic hypokyphosis could be obtained. METHODS: Seventy-eight patients who underwent an anterior spinal fusion using flexible threaded rods and nuts (Harms-MOSS instrumentation, De Puy-Motech-Acromed, Cleveland, OH) were analyzed and compared with 100 patients who underwent posterior spinal fusion with multisegmented hook systems. Parameters of comparison included coronal and sagittal correction, balance, distal lumbar fusion levels, and complication. All patients had idiopathic thoracic curves of King Types II to V. The average age at surgery was 14 years in each group, the average preoperative curve 57 degrees, and the minimum duration of follow-up for all patients 24 months. All data were collected prospectively and analyzed via Epl into statistical analysis (Centers of Disease Control, Atlanta, GA). RESULTS: Average coronal correction of the main thoracic curve was 58% in the anterior group and 59% in the posterior group (P = 0.92). Analysis of sagittal contour showed that the posterior systems failed to correct a preoperative hypokyphosis (sagittal T5 to T12 less than 20 degrees) in 60% of cases, whereas 81% were normal postoperatively in the anterior group. However, hyperkyphosis (sagittal T5 to T12 greater than 40 degrees) occurred after surgery in 40% of the anterior group when the preoperative kyphosis was greater than 20 degrees. Postoperative coronal balance was equal in both groups. An average of 2.5 (range, 0-6) distal fusion levels were saved using the anterior spinal instrumentation according to the criteria used for determining posterior fusion levels in this study. Selective fusion of the thoracic curve (distal fusion level T11, T12, L1) was performed in 76 of 78 patients (97%) in the anterior group as compared with only 18 of 100 (18%) in the posterior group. Surgically confirmed pseudarthrosis occurred in 4 of 78 patients (5%) in the anterior group and in 1 of 100 patients (1%) in the posterior group (P = 0.10). Loss of correction greater than 10 degrees occurred in 18 of 78 patients (23%) in the anterior group and in 12 of 100 patients (12%) in the posterior group (P = 0.01). Implant breakage occurred in 24 patients (31%) of the anterior group and in only 1 patient (1%) of the posterior group. CONCLUSIONS: 1) Coronal correction and balance were equal in both the anterior and posterior groups, even though the anterior group had the majority of curves (97%) fused short or to L1, whereas only 18% were fused short or to L1 in the posterior group. 2) In the anterior group there was a better correction of sagittal profile in those with a preoperative hypokyphosis less than 20 degrees. However, hyperkyphosis (with a mean of 54 degrees) occurred in 40% of those in the anterior group with a preoperative kyphosis of more than 20 degrees. 3) An average of 2.5 lumbar levels can be saved with anterior fusion and instrumentation according to the criteria used for choosing posterior fusion levels in this study. 4) Using the 3.2-mm flexible rod in this study, loss of correction, pseudarthrosis, and rod breakage were unacceptably highe