Ventral derotation spondylodesis. A review of 22 cases

Twenty-two patients with major lumbar or thoracolumbar curves were treated with Zielke's modification of the Dwyer instrumentation, termed the "ventral derotation spondylodesis (VDS) system. In 16 patients, this was followed by planned second-stage posterior Harrington instrumentation and fusion. Six patients with adolescent idiopathic scoliosis were treated with VDS instrumentation and fusion alone. In neuromuscular and adult idiopathic scoliosis, a combined approach resulted in excellent curve correction and a high rate of successful fusion. In adolescent idiopathic scoliosis, VDS instrumentation alone resulted in excellent curve correction while permitting a shorter fusion length than conventional posterior Harrington instrumentation.     

Results with Zielke instrumentation for idiopathic thoracolumbar and lumbar scoliosis

Thirty-one patients (23 adolescent, eight adult) underwent spinal fusions with Zielke instrumentation for idiopathic thoracolumbar and lumbar scoliosis. Their curves averaged 55.2 degrees. In most patients the length of fusion did not extend beyond the major curve. Correction of scoliosis was 82% in adolescents and 59% in the adults. The kyphotic component of the curves was corrected from an average of 21 degrees to 8 degrees. Correction of the spinal vertebra rotation was 46% in the adolescent patients. The tilt angle of the vertebra at the lower end of the curve was reduced significantly. The fusion rate was 93.5%. Two of the adult patients developed pseudarthrosis. Major complications were not encountered. The Zielke instrumentation system in the management of idiopathic thoracolumbar and lumbar scoliosis offers the advantages of a relatively good correction and minimal segment fusion.     

Zielke instrumentation

Zielke modified Dwyer's anterior spinal instrumentation to produce the Ventral Derotational Spondylodesis (VDS) System. The primary indication for VDS instrumentation is the treatment of progressive, single, major lumbar or thoracolumbar curves in idiopathic scoliosis. The surgical technique, including selection of appropriate curvatures and levels of instrumentation, is described. A group of 25 consecutive patients undergoing VDS instrumentation for lumbar or thoracolumbar curvatures was reviewed. The average correction of the major curve was 76%. The minor curvature was corrected with an average of 47%. A significant complication was a 20% incidence of pseudarthrosis and rod breakage. The implications of these problems are discussed. Zielke instrumentation is a powerful technique for the correction of selected curves. The system provides greater correction of the major curve, improved frontal and sagittal alignment, and preservation of distal motion segments.     

Anterior surgery with short fusion using the Zielke procedure for thoracic scoliosis: focus on the correction of compensatory curves

Anterior instrumentation is recommended to correct idiopathic thoracolumbar or lumbar scoliosis through short fusion within the major curve. Only a few reports exist of anterior surgical correction for thoracic scoliosis. This study assessed the results of Zielke instrumentation for thoracic curve and analyzed the three-dimensional correction of deformity, especially correction of the uninstrumented compensatory curve. Seventeen patients, who had undergone selective thoracic correction and fusion using the Zielke procedure to treat thoracic scoliosis, had been followed for at least 3 years. Three-dimensional correction was evaluated radiographically. Furthermore, three-dimensional back deformities were evaluated using a topographic body scanner. Twelve patients with a single thoracic curve and five with a double curve were all female, with a mean age of 14.6 years. The preoperative main thoracic curve was 54.8 degrees +/- 10.5 degrees (range, 40-78 degrees), and it was 23.8 degrees +/- 10.5 degrees (range, 7-40 degrees) at the final follow-up examination (p < 0.0001). The average correction rate of the main curves was 56.6%. By correcting the thoracic curve, the upper and lower compensatory curves were corrected spontaneously without surgical instrumentation, with average correction rates of 45.1% and 50.2%, respectively. The average correction loss of the main curve was 2.3 degrees. The hump angle measured using a topographic body scanner decreased from 12.8 degrees +/- 4.5 degrees to 8.4 degrees +/- 4.3 degrees after surgery (p = 0.0001). Of the three patients in whom the rod broke up, only one showed a correction loss of 10 degrees; however, bony fusion was obtained. Anterior short fusion for thoracic scoliosis appears to offer significant correction, stabilization, and spontaneous correction of the compensatory lumbar curve without limiting lumbar motion.     

Is the Cotrel-Dubousset really universal in the surgical treatment of idiopathic scoliosis?

We reviewed the results of 22 cases of Cotrel-Dubousset (C-D) instrumentation, 16 cases of anterior approach, and 200 cases of posterior approach by Harrington instrumentation and modifications of Harrington procedure. Posterior spinal fusion and instrumentation by C-D gives better correction and stabilization in thoracic and balanced double major curves. We no longer use the Harrington procedure and its modification. In lumbar and short thoracolumbar curves, VDS is still preferred. In some double major curves combined procedures, VDS and C-D are used to obtain more correction with a shorter fusion area.     

Ventrale und dorsale korrigierende und stabilisierende Verfahren bei idiopathischer Skoliose

The age of standardized instrumented scoliosis correction and stabilization began with Harrington instrumentation (HI). With HI, satisfactory long-term correction of the frontal plane averaged approximately 50%, but without notable derotational capabilities. The distraction of the concavity leads to reduction of the sagittal contour of the spine (flat back), which is biomechanically disadvantageous. The newer multisegmentally attached implant systems avoid this disadvantage. The first prototypes of these systems were Luque- (SSI) Cotrel-Dubousset instrumentation. Ideal indications for posterior instrumented curve correction are structural idiopathic double major curves and flexible single curves. However, even with these newer doublerod systems derotation is low, because derotation is, without any doubt, related to anterior release and thus decoupling of the segments by means of disc resection. The optimum method of correction and stabilization of scoliosis using the anterior approach is the ventral derotation spondylodesis (VDS), according to Zielke, who considers it to be a major improvement over Dwyer instrumentation. VDS is the first implant system with which true three-dimensional, segmental curve correction was made possible. Long term correction of the frontal plane and derotation averages approximately 70% and 50%, respectively. Ideal indications are single lumbar, thoracolumbar and thoracic curves. In our experience, the so-called kyphogenic effect of VDS due to anterior convex compression, can be counteracted by derotation and preserving disc space height with weight bearing bone grafts or cages. The low internal stabilizing capabilities with the risk of rod fracture and pseudarthrosis are unfavorable. They make long term cast or brace treatment necessary postoperatively. Meanwhile, the disadvantage of the low internal stabilizing capabilities of VDS has been overcome with the development of the primary stable Halm-Zielke instrumentation and other primary stable anterior fixation systems.     

Ventrale Skolioseoperationen

For more than 2 decades ventral derotation spondylodesis (Zielke VDS) as a major improvement over Dwyer instrumentation (DI) was the gold standard of instrumented curve correction and stabilization from the anterior approach. As the first available system it enables a true three-dimensional curve correction. A disadvantage is the low internal stabilization capability with a need for long-term external stabilization by means of cast and brace treatment postoperatively. Meanwhile with the development of modern single and dual solid rod systems these disadvantages can be avoided completely. Video-assisted (thoracoscopic) anterior scoliosis surgery accounts for less than 2% of anteriorly treated scoliosis cases, mainly due to a long operating time and significant learning curve. From the posterior approach the Cotrel-Dubousset instrumentation (CDI) as a polysegmentally attached posterior hook threaded dual rod system used to be state of the art for a long time, since it eliminated the disadvantages of Harrington instrumentation (HI) in terms of only one-dimensional correction and low stabilization capabilities. However even with CDI effective derotation was impossible. In posterior scoliosis surgery there is a strong trend away from hook systems towards transpedicular segmentally fixed dual rod systems not only in the lumbar spine but also in the thoracic area. Advantages of these newer techniques are shorter fusion, improved correction, and less loss of correction over time. Advantages of modern anterior instrumentation systems in comparison to posterior transpedicular instrumented dual rod systems are less blood loss, better derotation, slightly shorter fusion levels, and a better influence on sagittal plane control or improvement especially for hypokyphotic thoracic scoliosis cases. Our data also document a superior spontaneous correction of the lumbar curve after selective anterior instrumented correction (Lenke 1B+C), although other studies could not find significant differences. In our experience the neurological risk of anterior instrumented correction is also lower than that of posterior scoliosis surgery, although the morbidity and mortality data of the Scoliosis Research Society could not prove that anymore in recent years. A negative effect of anterior transthoracic scoliosis surgery in comparison to posterior surgery is a more negative effect on lung function, which improves slower after surgery and does not quite reach the levels of posterior surgery at follow-up. But new data on posterior segmental transpedicular correction and fusion also prove a lordosating effect with negative effect on lung function.     

Analysis of results with Zielke instrumentation for thoracolumbar and lumbar curvature

Thirty-nine patients (idiopathic in 26, paralytic in 11 and congenital in 2) treated by Zielke instrumentation with fusion for thoracolumbar and lumbar curvature were reviewed. The average follow-up was 34 months. The corrections of scoliosis was 76% in the adolescent idiopathic group, 59% in the adult idiopathic group and 55% in the paralytic group; rotation corrected (38%). Kyphosis was reduced from 61 degrees to 20 degrees on the average by derotating the spine using the derotator followed by placing bone graft in the anterior disc spaces. The tilt angle of the lower end vertebra in the idiopathic group and the pelvic obliquity angle in the paralytic group were corrected remarkably. Fusion rate was 92.3%. Two of three pseudarthrosis were repaired by Harrington instrumentation and fusion. One was free from symptoms. Complications were frequent, though in most cases only minor.     

Luque rod instrumentation in the treatment of adolescent idiopathic scoliosis. A comparative study with Harrington instrumentation

Adolescent idiopathic scoliosis in 152 patients was treated by Luque L-rod instrumentation and early mobilisation without external support. This series was compared with a matched group of 156 patients treated by Harrington instrumentation and immobilised in an underarm jacket for nine months. All the operations in both groups were performed by one surgeon and the patients were followed prospectively for more than two years. Correction of the scoliosis in the frontal plane was similar in both groups. However, the normal sagittal contour was better maintained with Luque rods, especially in the thoracolumbar and lumbar regions, and provided less loss of correction than with Harrington rods. Neither method significantly derotated the scoliosis. All the patients with Luque instrumentation developed a solid fusion despite breakage of the sublaminar wires at one or two levels in 4.9%. There were no major neurological complications with either type of instrumentation.     

An analysis of the results of Dwyer and Zielke instrumentations in the treatment of scoliosis

From 1974 to the end of 1985, 76 operations for correction of scoliosis by the anterior approach using the techniques of Dwyer and Zielke were carried out. This review reports the results of follow-up examination of 55 patients. Differences concerning etiology of curvatures and age of patients are considerable. Twelve patients underwent operation with the Dwyer instrumentation; in the remaining 43 patients the Zielke instrumentation (VDS) was used. Complications were rare and could be managed easily. In the Dwyer group an average correction of 78% could be obtained; the results obtained with the VDS instrumentation were slightly better, with 87% correction of curvatures. With reference to pelvic obliquity, both methods produced similarly good results of 70% and 73% respectively. As for stability, the VDS system is superior to the Dwyer technique; it also offers the possibility of derotation and better lordosis.     

Anterior and posterior instrumentation and fusion of thoracolumbar scoliosis due to myelomeningocele

Twenty-three patients with severe paralytic thoracolumbar scoliosis due to a myelomeningocele were treated by a two-stage procedure. Before operation the mean scoliosis was 98 degrees: after the first-stage procedure, an anterior spinal fusion and correction with Dwyer instrumentation, this was reduced to a mean of 45 degrees. Approximately two weeks later a posterior spinal fusion with Harrington instrumentation was performed, further reducing the scoliosis to a mean of 29 degrees. The pelvic obliquity also was reduced from a mean of 32 degrees to 6 degrees. Although such management carries risks (one patient died of cardiorespiratory failure after the first stage and one patient was made worse), 21 of the 23 patients had improved posture and function.     

Segmental pedicle screw instrumentation in idiopathic thoracolumbar and lumbar scoliosis

The role of posterior correction and fusion in thoracolumbar and lumbar scoliosis as well as pedicle screw instrumentation in scoliosis surgery are matters of debate. Our hypothesis was that in lumbar and thoracolumbar scoliosis, segmental pedicle screw instrumentation is safe and enables a good frontal and sagittal plane correction with a fusion length comparable to anterior instrumentation. In a prospective clinical trial, 12 consecutive patients with idiopathic thoracolumbar or lumbar scolioses of between 40° and 60° Cobb angle underwent segmental pedicle screw instrumentation. Minimum follow-up was 4 years (range 48– 60 months). Fusion length was defined according to the rules for Zielke instrumentation, normally ranging between the end vertebrae of the major curve. Radiometric analysis included coronal and sagittal plane correction. Additionally, the accuracy of pedicle screw placement was measured by use of postoperative computed tomographic scans. Major curve correction averaged 64.6%, with a loss of correction of 3°. The tilt angle was corrected by 67.0%, the compensatory thoracic curve corrected spontaneously according to the flexibility on the preoperative bending films, and led to a satisfactory frontal balance in all cases. Average fusion length was the same as that of the major curve. Pathological thoracolumbar kyphosis was completely corrected in all but one case. One patient required surgical revision with extension of the fusion to the midthoracic spine due to a painful junctional kyphosis. Eighty-five of 104 screws were graded “within the pedicle”, 10 screws had penetrated laterally, 5 screws bilaterally and 4 screws medially. No neurological complications were noted. In conclusion, despite the limited number of patients, this study shows that segmental pedicle screw instrumentation is a safe and effective procedure in the surgical correction of both frontal and sagittal plane deformity in thoracolumbar and lumbar scoliosis of less than 60°, with a short fusion length, comparable to anterior fusion techniques, and minimal loss of correction. Received: 23 September 1999 Revised: 20 January 2000 Accepted: 26 January 2000     

Thoracolumbar scoliosis in cerebral palsy. Results of surgical treatment.

Of 294 patients with cerebral palsy seen from 1960 to 1972, forty-two had clinically significant lumbar and thoracolumbar scoliosis (31 to 135 degrees) and thirty-three were treated by spine surgery: ten by Harrington instrumentation and posterior spine fusion, eighteen by the Dwyer procedure and anterior fusion, and five by a two-stage combined anterior and posterior fusion. Evaluation of the results after eighteen to sixty-eight months showed: relief of pain in seventeen cases, improved sitting tolerance in seventeen, less nursing care needed in three, less equipment required in six, ability to use equipment providing more function in three, placement in a facility where less care was required in two, and improved eating patterns in two. Only the combined procedure appeared to give adequate correction and a low incidence of pseudarthrosis.     

Short posterior fusion for patients with thoracolumbar idiopathic scoliosis.

Fifteen percent of all scolioses are idiopathic thoracolumbar and are characterized by significant imbalance in the frontal plane. A large curve of more than 40 degrees creates a trunk shift and under these circumstances an active correction is necessary. It is this imbalance that is the cause of increasing muscular fatigue. Arthritic changes may appear later which also are responsible for pain. The aim of a surgical procedure is to stop the progression of scoliosis, to obtain the reequilibrium of the spine in a frontal and a sagittal plane, and to correct the deformity. During the 1960s Dwyer6 developed his anterior instrumentation mainly for thoracolumbar and lumbar curves. In 1980 Hall developed the concept of a short anterior fusion with overcorrection for patients with thoracolumbar curves. In the present study 10 patients are presented who were operated on for thoracolumbar adolescent idiopathic scoliosis using short posterior fusion instrumented by segmental convex transpedicle screw fixation and concave hook stabilization. With a mean followup of 49 months, the results show that frontal and sagittal balances are restored. In the present study all patients achieved frontal and sagittal balances at the last followup. The angular correction achieved by surgery always is more effective than what is visualized in radiographs of the patient in the bending position obtained before surgery. The correction of the major curve in the frontal plane improved from a mean angle of 47 degrees preoperatively to 14 degrees postoperatively and to 17 degrees at the last followup. In all cases, mobile discs in the lower lumbar area are open. The posterior short fusion has the same power of correction as the anterior fusion with the advantage of an easier surgical approach and a better control of the lordosis. This paper will describe the operative indications, the choices of instrumented levels, and the medium term followup results.     

Dwyer instrumentation of the spine

The evolution of the Dwyer procedure during the past 10 years has enabled us to better define the indications and contraindications for the procedure. The role of the Dwyer procedure in the treatment of thoracolumbar or lumbar curves in both the adolescent and the adult has been found to be significant. When combined with Harrington rod instrumentation it can be used for either paralytic curves, curves associated with pelvic obliquity, or curves in which posterior elements are absent.     

Spine fusion in cerebral palsy with L-rod segmental spinal instrumentation. A comparison of single and two-stage combined approach with Zielke instrumentation

The benefits of achieving rigid internal fixation and eliminating the need for postoperative external orthotic support with L-rod spinal instrumentation made it desirable for use in the surgical treatment of neuromuscular scoliosis. From May 1981 to May 1985, 31 severely involved cerebral palsy patients with progressive spinal deformity underwent posterior fusion and L-rod instrumentation. All patients except one were nonambulatory. Surgical indications included prevention of curve progression, correction of pelvic obliquity, and achievement of balanced spinal alignment in order to improve sitting balance and tolerance without external spinal orthotic support. Ten patients (Group I), with an average age of 15.2 years, with double major or flexible paralytic C-curves or scoliosis measuring less than 70 degrees, underwent posterior fusion and L-rod instrumentation only. Twenty-one patients (Group II), with an average age of 22.1 years, with thoracolumbar, lumbar, or rigid paralytic C-curves or scoliosis measuring greater than 70 degrees, underwent initial anterior release, bone grafting, and Zielke instrumentation followed by second-stage L-rod instrumentation. In Group I, scoliosis averaged 57 degrees and postoperatively 27 degrees (53% correction). In Group II, scoliosis averaged 88 degrees and postoperatively 36 degrees (63% correction). Fifteen Group II patients had posterior fusion extend into the sacrum using the Galveston technique. Six Group II patients were not fused into the sacrum. Scoliosis and pelvic obliquity were corrected in both groups. Torso decompensation improved to 2.7 cm in the Galveston group, but increased to 5.6 cm at follow-up in the patients not fused into the sacrum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anterior instrumentation in idiopathic scoliosis: a minimum follow-up of 10 years

Summary. One hundred and thirty-four patients with idiopathic scoliosis were treated between 1973 and 1993 in our hospital, and 53 were followed for a minimum of 10 years in a retrospective study. Forty-five were female and 8 male with an average age of 32 years at follow up. Dwyer instrumentation was used in 17 and Zielke in 36. The curve was thoracic in 16, thoracolumbar in 27 and lumbar in 10. The average preoperative Cobb angle was 64°. The average angle at follow up was 21° with 62% of the average correction maintained (61% in the Dwyer and 65% in the Zielke). Most patients were satisfied subjectively and we recommend this type of operation.

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Résumé. Entre 1973 et 1993, 134 patients atteints de scoliose idiopathique ont été traités selon une instrumentation antérieure a l’hospital National de Murayama. De ces patients, 53 ont été suivis avec un minimum de 10 ans. Il y avait 45 femmes et 8 hommes avec une moyenne d’age de 32,6 ans. 17 patients ont été traités selon l’instrumentation Dwyer, et 36 selon Zielke. La courbure était thoracique chez 16 patients, thoracolumbaire chez 27 patients et lombaire chez 10 patients. La moyenne de l’angle de Cobb préopératoire était 64.7°. La moyenne de l’angle à terme était 21.3°, c’est-à-dire 62.3% en moyenne de correction de la scoliose (61.7% dans l’instrumentation Dwyer et 65% dans l’instrumentation Zielke). La majorité des patients étaient satisfaits dans une estimation subjective. Avec cette étude nous sommes assez satisfaits de nos resultats et recommandons l’instrumentation antérieure pour la correction de la scoliose.

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Accepted: 29 February 1996     

The role of Harrington instrumentation and posterior spine fusion in the management of adolescent idiopathic scoliosis

The Harrington instrumentation system was the first widely used, internationally accepted internal fixation system for the correction of idiopathic scoliosis when combined with a spinal arthrodesis. It has been generally available to the orthopedic surgeon for more than 25 years, and therefore its capabilities and limitations have been identified through this long experience. Its implantation requires minimal invasion of the spinal canal and is associated with a low (less than 0.5 per cent) incidence of neurologic complications. It provides predictable correction of spinal deformity with little subsequent loss of correction. When compared with other newer, more complex internal fixation systems for spinal deformities, the Harrington system has a shorter, less difficult "learning curve"; requires less operating time and blood loss to insert; implants a smaller mass of metal; and in some cases costs substantially less for the implant system. The Harrington system has an extremely low incidence of hook dislodgment and pseudoarthrosis formation in single thoracic curves, being reported as near zero for these curves in two recently published series. Conversely, there are some disadvantages to the Harrington system when compared with other types of fixation. It has limited ability to provide sagittal plane control. It does not effectively and predictably derotate the spine. A recent study showed that at an average of 4 years postoperatively, nearly two thirds of the patients had an actual increase in their rib prominence. The pseudoarthrosis rate is high, up to 4 per cent, in the thoracolumbar and lumbar spine. Hook dislodgment approaches 3 per cent when used below the thoracic region. Another disadvantage is the necessity for postoperative external support. As a result, the Harrington system remains an excellent means of treating single and double thoracic idiopathic curves in a safe and predictable manner, while admittedly having limited derotation and sagittal plane control. Other systems that are more sophisticated at segmental fixation of the spine appear to be more appropriate for scoliotic deformities requiring fusion of the thoracolumbar or lumbar spine and those associated with significant sagittal plane deformities.     

Surgery of spinal deformity in cerebral palsy. Twelve years in the evolution of scoliosis management

In order to assess the lessons learned from 12 years of surgery on patients with cerebral palsy and spinal deformity, the cases may be divided into three groups classified according to type of posterior spinal fusion, instrumentation, and time period. Group I (1976-1980) included patients who had Harrington rods, usually with Dwyer instrumentation. Group II (1980-1985) consisted of patients with unlinked Luque or wired-in Harrington rods. Group III (1985-1988) comprised patients with a unit Luque rod extending to the pelvis. Most patients were retarded nonwalkers who had total body involvement, pelvic obliquity, and severe thoracolumbar curves (Group I average, 97 degrees; Group II average, 72 degrees; Group III average, 89 degrees). The frontal plane correction at follow-up study averaged 51% in Group I, 47% in Group II, and 76% in Group III. The correction of the pelvic obliquity averaged 71% in Group I, 58% in Group II, and 86% in Group III. The general trend was toward longer fusion, use of the unit 0.625-cm Luque rod, and first-stage anterior discectomy and fusion without anterior instrumentation. The second-stage posterior arthrodesis and fusion is now performed only one week after the first-stage anterior procedure. Skeletal traction has been abandoned. The Luque rod instrumentation without fusion has also been abandoned.     

各型内固定矫形术治疗脊柱侧凸效果评价

目的评价不同内固定矫形术治疗脊柱侧凸的效果。方法对１９８４～１９９７年用不同手术方法矫治１２５例１００°以内脊柱侧凸患者的治疗和随诊资料进行研究,手术方法包括Ｈａｒｉｎｇｔｏｎ、Ｌｕｑｕｅ、联合ＨａｒｉｎｇｔｏｎＬｕｑｕｅ、ＣＤ、Ｚｉｅｌｋｅ、前路松解加后路手术和俄式手术等,对不同方法的优缺点及各自的矫正情况、身高变化、手术时间、术中输血量、住院时间、术后并发症和矫正度丢失情况及其原因进行比较分析。结果Ｈａｒｉｎｇｔｏｎ法矫正效果比其它方法差而且并发症多;Ｌｕｑｕｅ法费时且有潜在脊髓损伤之忧;ＣＤ法有三维矫正作用,矫正效果好,未见脱钩、断棍;含前路手术的方法远期Ｃｏｂｂ角度丢失少,其中前路松解加后路手术（ＣＤ术）方法简便易行,效果好;俄式手术作为一种探索中的不影响脊柱生长发育的新型脊柱侧凸内固定矫形术,有一定优越性。结论在不进行脊柱融合的新技术发展成熟前,ＣＤ术对生长发育中的青少年脊柱侧凸患者是一种较好的治疗方法