Short posterior fusion for patients with thoracolumbar idiopathic scoliosis

Determination of the distal fusion level in the management of thoracolumbar and lumbar adolescent idiopathic scoliosis using pedicle screw instrumentation

Study Design

A retrospective study.

Purpose

To determine the exact distal fusion level in the management of thoracolumbar/lumbar adolescent idiopathic scoliosis (TL/L AIS) using pedicle screw instrumentation (PSI).

Overview of Literature

The selection of distal fusion level remains controversial in TL/L AIS.

Methods

Radiographic parameters of 66 TL/L AIS patients were analyzed. The patients were grouped according to the distal fusion level; L3 group (fusion to L3, n=58) and L4 group (fusion to L4, n=8). The L3 group was subdivided into L3A (L3 crosses the mid-sacral line with rotation of less than grade II, n=33) and L3B (L3 does not cross the mid-sacral line or rotation is grade II or more, n=25) based on both bending radiographs. All of the patients in the L4 group had the same location and rotation of L3 in bending films as that of patients in the L3B group. An unsatisfactory result was defined as a lowest instrumented vertebral tilt (LIVT) of more than 10° or coronal balance of more than 15 mm.

Results

Among the 3 groups, there was a significantly lesser correction in the TL/L curve and LIVT in the L3B group. Unsatisfactory results were obtained in 3 patients (9.1%) of the L3A group, in 15 patients (68.2%) of the L3B group, and in 1 patient (12.5%) of the L4 group with a significant difference.

Conclusions

In TL/L AIS treatment with PSI, the curve can be fused to L3 with favorable radiographic outcomes when L3 crosses the mid-sacral line with rotation of less than grade II in bending films. Otherwise, fusion has to be extended to L4.

Anterior instrumentation (dual screws single rod system) for the surgical treatment of idiopathic scoliosis in the lumbar area: a prospective study on 33 adolescents and young adults, based on a new system of classification

OBJECTIVES/PURPOSE

The choice of anterior instrumentation in the treatment of lumbar scoliosis in adolescents and young adults is not a new topic for the authors. The first results achieved using the Dwyer surgical modality were reported by one of the authors followed by the results achieved using Zielke (VDS) instrumentation. Today, new techniques and new instrumentations have been developed that challenge the instrumentation choices. Here we describe how the new system of classification of scoliotic curves we developed has been used as a basis for treating idiopathic scoliosis in lumbar area in adolescents and young adults using an anterior approach.

MATERIALS

A prospective study was carried out between 1998 and 2010 at two hospital centers on 33 adolescents and young adult with idiopathic lumbar scoliosis involving curves of three kinds, on whom surgical treatment was performed using a single solid rod. Topography of curves: our system of classification includes curves corresponding to the following three type of scoliosis: Type K I: double thoracic and lumbar curves (lumbar predominant) scoliosis (17 cases) mean age 16 years all female patients. Mean Cobb angle of lumbar curve 41°. Mean Cobb angle of thoracic curve 28°. The lumbar curve was left hand convex in 15 cases and right hand convex in 2 cases. Horizontal tilting of L4 mean value 22°. C7 offset mean value 3 cm. Type K IV A: unbalanced thoracolumbar scoliosis (13 cases) mean age 17 years, ten female patients and three male patients. Mean Cobb angle of thoracolumbar curve 39°. The thoracolumbar curve was left hand convex 4 times and right hand convex 9 times. Horizontal tilting of L4 mean value 18°. C 7 offset mean value 2.5 cm. Type K VI A: real lumbar (three cases). Age: 17, 15 and 13 years; all female patients. Cobb angle of the lumbar curve 66°, 29° and 70° (all LH convex). Horizontal tilting of L4: 40°, 20° and 46°. C 7 offset: 7 cm, 1 cm and 4 cm.

METHODS

Surgical instrumentation: We used the EUROS AZUR anterior instrumentation for all the procedures. Cages have been used on five patients at the lower stages. Number of vertebrae instrumented: mean five vertebrae. The patients did not wear postoperative orthosis. Mean duration of procedure: 3 h 50 min. Mean blood loss: 350 cm(3).

RESULTS

Type K I scoliosis (17 cases): Mean follow-up: 6 years. Correction of the lumbar curve Cobb angle: the mean angle has been corrected from 41° to 21°. Number of vertebrae instrumented: 4:6 times and 5:11 times. Correction of the upper thoracic curve Cobb angle: mean angle corrected from 28° to 19°. Correction of L4 horizontal tilting: mean residual was 7°. Correction of C 7 offset: mean 0.7 cm. Type K IV A scoliosis (13 cases): mean follow-up: 4 years. Correction of the lumbar curve Cobb angle: the mean angle has been corrected from 39° to 16°. Mean number of instrumented vertebrae: 5 (4:4 times, 5:6 times and 6:3 times.) Correction of L4 horizontal tilting: mean residual 5°. Correction of C 7 offset: mean 0.7 cm. Type K VI A scoliosis (three cases): mean follow-up: 7, 2 and 4 years; Correction of the lumbar curve Cobb angle: the angles have been corrected from 66° to 15°, from 29° to 11° and from 70° to 28°. Number of instrumented vertebrae: 5, 4 and 6. Correction of L4 horizontal tilting: residual tilting of 8°, 7° and 17°. Correction of C 7 offset: 1 cm, 0 cm and 1 cm.

COMPLICATIONS

There has been no report early or late septic or vascular or neurological complications. Instrumentation failure: there were three cases of screw breakage, all occurred on the lowest implant. Revision surgery was undertaken in both cases, only the last plate needed to be replaced and the rod could be kept without any other modification of the construct. In both cases, fusion has been achieved without any loss of correction. The mean loss of correction of the main curve was 2.5° for the three series.

CONCLUSIONS

Anterior instrumentation of lumbar idiopathic scoliosis gives highly satisfactory morphological and functional results, since the lumbar musculature is spared and the instrumentation placed at the apex of the curvature has selective effects. Despite our preference and that of other surgeons throughout the world for anterior instrumentation, we are still a minority in comparison with the users of posterior instrumentation. There are several reasons for this reticence, including surgeons' training and ideas about pedicular screw fixation, but the main reason has been the lack of a sufficiently exact system of classification. Previous comparative studies between the anterior and posterior approaches have been biased by the use of an excessively restrictive mode of classification (lumbar/thoracolumbar) of the curves. Real lumbar scoliosis, unbalanced thoracolumbar scoliosis and thoracic and lumbar double curve (lumbar predominant) scoliosis should be properly defined before being compared.

The evaluation of short fusion in idiopathic scoliosis

BACKGROUND

Selective thoracic fusion in type II curve has been recommended by King et al. since 1983. They suggested that care must be taken to use the vertebra that is neutral and stable so that the lower level of fusion is centered over the sacrum. Since then there has been the trend to do shorter and selective fusion of the major curve. This study was conducted to find out whether short posterior pedicle instrumentation alone could provide efficient correction and maintain trunk balance comparing to the anterior instrumentation.

MATERIALS AND METHODS

A prospective study was conducted during 2005-2007 on 39 consecutive cases with idiopathic scoliosis cases King 2 and 3 (Lenke 1A, 1B), 5C and miscellaneous. Only the major curve was instrumented unless both curves were equally rigid and of the same magnitude. The level of fusion was planned as the end vertebra (EVB) to EVB fusion, although minor adjustment was modified by the surgeons intraoperatively. The most common fusion levels in major thoracic curves were T6-T12, whereas the most common fusion levels in the thoraco-lumbar curves were T10-L3. Fusion was performed from the posterior only approach and the implants utilized were uniformly plate and pedicle screw system. All the patients were followed at least 2 years till skeletal maturity. The correction of the curve were assessed according to type of curve (lenke IA, IB and 5), severity of curve (less than 450, 450-890 and more than 900), age at surgery (14 or less and 15 or more) and number of the segment involved in instrumentation (fusion level less than curve, fusion level as of the curve and fusion more than the curve)

RESULTS

The average long-term curve correction for the thoracic was 40.4% in Lenke 1A, 52.2% in Lenke 1B and 56.3% in Lenke 5. The factors associated with poorer outcome were younger age at surgery (<11 years or Risser 0), fusion at wrong levels (shorter than the measured end vertebra) and rigid curve identified by bending study. However, all patients had significant improved trunk balance and coronal hump at the final assessment at maturity. Two patients underwent late extension fusion because of junctional scoliosis.

CONCLUSIONS

With modern instrumentations, the EVB of the major curve can be used at the end of the instrumentation in most cases of idiopathic scoliosis. In those cases with either severe trunk shift, younger than 11 years old, or extreme rigid curve, an extension of one or more levels might be safer. In particular situations, the concept of centering the lowest vertebra over the sacrum should be adopted.

Anterior spinal fusion versus posterior spinal fusion for moderate lumbar/thoracolumbar adolescent idiopathic scoliosis: a prospective study

STUDY DESIGN

A prospective study.

OBJECTIVE

Comparison study of radiologic and clinical outcomes, efficiency, and cost between anterior spinal fusion (ASF) and posterior spine fusion (PSF) in surgical treatment of moderate lumbar/thoracolumbar adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

ASF and PSF indicated for lumbar and thoracolumbar adolescent idiopathic scoliosis surgical treatment have respective advantages and disadvantages. However, up until today, a related prospective AIS comparative study has rarely been reported.

METHODS

Thirty-two cases in this prospective study with patients enrolled in either method A or B alternately in a sequence were divided into 2 groups. Group A underwent ASF with single solid rod and single screw constructs, and group B underwent PSF with segmental total pedicle screw system. Inclusion criteria were: (1) AIS diagnosis; (2) diagnosis classification as Lenke5CN type; (3) Cobb angles 35 degrees-60 degrees on anteroposterior view radiographs. Exclusion criteria were: (1) a history of spinal surgery; (2) age younger than 10 years; (3) Risser sign 0 degree; (4) lumbar/thoracolumbar kyphosis. All patients were observed with 2-year minimum follow-up (24-46 months). Clinical and radiologic outcomes of both groups A and B were analyzed.

RESULTS

Statistical t test or Mann-Whitney U test demonstrated no significant difference in preoperative age (P = 0.380), Risser sign (P = 0.733), magnitude (P = 0.936), flexibility (P = 0.815), apical vertebra rotation (AVR, P = 0.756), and apical vertebra translation (AVT, P = 0.355) of the lumbar/thoracolumbar curves, trunk shift (TS, P = 0.448), sagittal kyphosis from T5-T12 (P = 0.792) and sagittal lordosis from L1-L5 (P = 0.299). Average coronal correction of thoracolumbar/lumbar curves was 83% after surgery and 77% at follow-up in group A and 87% after surgery and 82% at follow-up in group B (P = 0.236 and P = 0.138). No significant differences were observed regarding correction of sagittal alignment, TS, AVT, AVR and hospitalization days on last follow-up between both groups (P > 0.05). No pseudarthrosis, reoperation, neurologic complications, infection, and no other problems were observed. Excellent clinical fusion results were present in all patients on their last follow-up. However, significant differences were evident in group A in regards to reduced operative time (P = 0.046), reduced estimated blood loss (P = 0.003), decreased blood transfusion (P = 0.006), reduced implants cost and hospitalization expenses (P = 0.000). Additionally, group A had shorter fusion levels than group B (p50 = 4 vs. p50 = 5, P = 0.003).

CONCLUSION

ASF versus PSF comparison in treating moderate lumbar/thoracolumbar AIS did not show significant differences in regards to safety or efficacy but demonstrated shorter fusion levels, reduced surgical trauma and costs in ASF.

A century of spine surgery: what can patients expect?

PURPOSE

To evaluate the hypothesis that spinal fusion surgery is an effective method to address spinal deformity-associated clinical problems, including magnitude of curvature (Cobb angle), pulmonary dysfunction, and pain.

METHOD

A systematic review was carried out using Science Citation Index (SCI) Expanded (1900 - present), Social Sciences Citation Index (1956 - present), Arts and Humanities Citation Index (1965 - present), Medline (1950 - present) and PubMed Central databases (1887 - present) to access information regarding efficacy of spine surgery in preventing or improving the health and function of patients diagnosed with scoliosis in adolescence.

RESULTS

Since 1950, more than 12,600 articles on scoliosis have been published, and nearly 50% (5721) focus on methods, rationale, outcome, and complications of surgical intervention. Among these, 82 articles have documented outcome for groups of > or =10 patients, treated for adolescent idiopathic scoliosis, and followed for at least 2 years after treatment. These data provide an overview of the impact of spine surgery on scoliosis for 5780 patients as surgery methods and approaches have evolved.

CONCLUSIONS

For most patients, a reduced magnitude of spinal curvature can be achieved through one or more spinal fusion surgeries. There is no evidence to support the premise that this result is correlated with improved pulmonary function or reduced pain.

Comparison of segmental pedicle screw instrumentation versus anterior instrumentation in adolescent idiopathic thoracolumbar and lumbar scoliosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

To compare the results of anterior instrumentation versus segmental pedicle screw instrumentation in adolescent idiopathic thoracolumbar and lumbar scoliosis.

SUMMARY OF BACKGROUND DATA

Anterior instrumentation is an established method of correcting adolescent idiopathic thoracolumbar and lumbar scoliosis. Posterior segmental pedicle screw instrumentation, with its more powerful corrective force over hooks, could offer significant advantages.

METHODS

A retrospective analysis was conducted on 36 consecutive female patients with adolescent idiopathic thoracolumbar and lumbar scoliosis who had surgery from December 1997. All had a minimum of 2-year follow-up. Eleven patients had posterior surgery.

RESULTS

Mean age at surgery was similar between both groups. Length of surgery was significantly shorter in the posterior group (189 minutes vs. 272 minutes). Length of hospital stay was shorter in the posterior group (6.2 days vs. 8 days). Estimated blood loss, duration of analgesia, and ICU stay did not differ significantly between the 2 groups. No complications were encountered in both groups at the latest follow-up. The magnitudes and flexibility of the thoracolumbar/lumbar curves did not differ significantly between the 2 groups. The number of levels in the major curve was also similar between the groups. Fusion levels were shorter in the anterior group (mean, 4.1 vs. 5.0). The percentage correction of scoliosis was similar between the 2 groups at all stages of follow-up, being 74% at 1 week postsurgery, 70% at 6 months postsurgery, 68% at 1 year postsurgery and latest follow-up for the anterior group, and 71% at 1 week postsurgery, 67% at 6 months postsurgery, 68% at 1 year postsurgery, and 67% at the latest follow-up for the posterior group. Thoracolumbar sagittal alignment at T11-L2 was maintained for both groups throughout the follow-up period. The incidence of proximal junctional kyphosis was higher in the posterior group (P < 0.01).

CONCLUSION

Surgical correction of both the frontal and sagittal plane deformity are comparable to anterior instrumentation. Shorter lengths of surgery and hospital stay are the potential benefits of posterior surgery. Posterior segmental pedicle screw instrumentation offer significant advantages and is a viable alternative to standard anterior instrumentation in idiopathic thoracolumbar and lumbar scoliosis.

Impact of spine surgery on signs and symptoms of spinal deformity

Paediatric scoliosis is associated with signs and symptoms including reduced pulmonary function, increased pain and impaired quality of life, all of which worsen during adulthood, even when the curvature remains stable. Spinal fusion has been used as a treatment for nearly 100 years. In 1941, the American Orthopedic Association reported that for 70% of patients treated surgically, outcome was fair or poor: an average 65% curvature correction was reduced to 27% at >2 year follow-up and the torso deformity was unchanged or worse. Outcome was worse in children treated surgically before age 10, despite earlier intervention. Today, a reduced magnitude of curvature obtained by spinal fusion in adolescence can be maintained for decades. However, successful surgery still does not eliminate spinal curvature and it introduces irreversible complications whose long-term impact is poorly understood. For most patients there is little or no improvement in pulmonary function. Some report improved pain after surgery, some report no improvement and some report increased pain. The rib deformity is eliminated only by rib resection which can dramatically reduce respiratory function even in healthy adolescents. Outcome for pulmonary function and deformity is worse in patients treated surgically before the age of 10 years, despite earlier intervention. Research to develop effective non-surgical methods to prevent progression of mild, reversible spinal curvatures into complex, irreversible structural deformities, is long overdue.

Proximal kyphosis after short posterior fusion for thoracolumbar scoliosis

Thoracolumbar idiopathic scoliosis usually is treated by anterior spinal fusion. However, short posterior spinal fusion that includes only the structural curve has been tried in a limited number of patients. The fusion may end cranially in the lower thoracic region and cause an increase in sagittal decompensation at the proximal junction. From July 1989 to July 1998, 14 patients were treated with thoracolumbar idiopathic scoliosis by short posterior spinal fusion. The lateral radiographs were evaluated preoperatively, immediately postoperative, and during followup. The focal kyphotic angle was used to examine the changes in focal sagittal alignment. A 10 degrees progression was defined as the radiographic criterion for the development of junctional kyphosis. Proximal junctional kyphosis occurred in six of the 14 patients, in which one patient needed revision surgery. In all six patients, the average preoperative lumbar lordosis was greater than 35 degrees, and decreased more than 10 degrees during surgery. In the five patients with a focal kyphotic angle larger than 10 degrees, four had proximal junctional kyphosis develop. According to the current findings, short posterior spinal fusion can be done only if the focal kyphotic angle proximal to the fusion is less than 10 degrees, and the lumbar lordosis must be preserved carefully during surgery.

Patient-based outcomes analysis of patients with single torsion thoracolumbar-lumbar scoliosis treated with anterior or posterior instrumentation: an average 5- to 9-year follow-up study

INTRODUCTION

Since the advent of single, stiff rod anterior instrumentation, and now dual rod anterior instrumentation, most thoracolumbar-lumbar scoliosis is treated with an anterior approach. We have previously reported a retrospective comparison of patients with single torsion thoracolumbar-lumbar scoliosis treated with either anterior or posterior instrumented fusion. The purpose of this study is to examine the patient-based outcomes in this cohort of patients at an average of 5 years (anterior instrumentation) and 9 years (posterior instrumentation).

MATERIALS AND METHODS

Inclusion criteria were as follows: 1) single torsion thoracolumbar or lumbar curve of <or=70 degrees; 2) thoracic curve bends to <or=20 degrees on nonstressed supine bends; and 3) thoracic kyphosis of <or=60 degrees. Fourteen patients were treated with posterior transpedicular instrumented fusion from 1989 to 1993 (none treated with anterior discectomy). Fourteen patients were treated with anterior, single, solid rod instrumented fusion from 1993 to 1996. SRS 22 was performed after surgery in 12 of 14 patients from the posterior group (average 9.2 years) and in 14 of 14 patients from the anterior group (average 5.1 years).

RESULTS

Posterior: The average age was 14.8 years (range 12-17.8 years). Curve correction at average 6.5 years (range 4.0-10.9 years) was 75%. The average lower instrumented vertebra was L3.1. There were no complications. Twelve of 14 patients completed SRS 22 at an average of 9.2 years (range 6.2-10.9 years). Domain scores for Pain, Self-Image, Function, Mental Health, Satisfaction, and Total were 3.8, 4.1, 4.0, 3.8, 4.5, and 4.1, respectively. Anterior: The mean age was 14.5 years (range 12.5-16.5 years). Curve correction at average 4.8 years (range 2.3-7.6 years) was 63% (instrumented segment 89%). The average lower instrumented vertebra was L2.6. Complications included one intercostal neuritis that resolved with suture removal, one broken inferior screw that healed with some loss of correction, and one pseudarthrosis treated successfully with posterior fusion. Fourteen of 14 patients completed SRS 22 at an average of 5.3 years (range 2.0-7.6 years). Domain scores for Pain, Self-Image, Function, Mental Health, Satisfaction, and Total were 4.1, 4.3, 4.4, 4.0, 4.5, and 4.3, respectively. There were no statistically significant differences in any of the domains or the Total score, although there was a trend toward improved function in the patients treated anteriorly. The follow-up was statistically longer in the posterior group.

CONCLUSION

At an average of 9 years of follow-up, patients treated with posterior transpedicular instrumentation have equivalent patient-based outcomes to patients treated with anterior single solid rod instrumentation at an average of 5 years of follow-up.