Harry L. Shufflebarger

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

The crankshaft phenomenon.

We reviewed 40 spinal fusions done prior to Risser stage I for idiopathic and paralytic scoliosis to evaluate postoperative curve progression. The 39 patients who had posterior fusion alone had progressive angulation and rotation of the spine over the postoperative follow-up period. The more immature the patient, the greater the resultant progression. This progression is an inevitable consequence of continued anterior spinal growth in the presence of a posterior fusion, and occurs without pseudarthrosis or hardware failure. Younger patients may require anterior and posterior fusion to achieve stable correction.

Intraobserver and Interobserver Reliability of the Classification of Thoracic Adolescent Idiopathic Scoliosis

The system described by King et al. is the standard method for the classification of thoracic adolescent idiopathic scoliosis. Although it is widely used and referenced, its reliability and reproducibility among scoliosis surgeons are unknown. We used a scoliosis case-presentation format to examine the interobserver and intraobserver reliability of the classification of thoracic adolescent idiopathic scoliosis with the system of King et al. Eight active, current members of the Scoliosis Research Society reviewed twenty-seven full-length radiographs that had been made before operative correction of the scoliotic deformity. On the basis of these images, which included posteroanterior and lateral radiographs made with the patient standing as well as right and left forced-side-bending radiographs made with the patient supine, the reviewers assigned a type to each curve according to the classification system of King et al. Kappa coefficients were used to test statistical reliability. The mean interobserver reliability of the classification was only 64 per cent (range, 54 to 77 per cent) when the responses of seven of the reviewers were compared with those of one of the originators of the classification. The mean kappa coefficient was 0.49 (range, 0.27 to 0.73), which indicates poor reliability. When each reviewers responses were compared with those of the other reviewers, the reliability was similarly poor (interobserver reliability, 55 per cent [range, 33 to 81 per cent] and mean kappa coefficient, 0.40 [range, 0.21 to 0.63]). Intraobserver reliability was evaluated in a trial in which five reviewers in a group setting were shown the same radiographs in a different order at two different viewings. Comparison of the results at the two viewings revealed a mean intraobserver reliability of 69 per cent (range, 56 to 85 per cent) and a mean kappa coefficient of 0.62 (range, 0.34 to 0.95), which indicates fair reliability. The current method of classification of adolescent idiopathic scoliosis does not appear to have sufficient intraobserver or interobserver reliability among scoliosis surgeons to portray curve types accurately. Thus, it may not help to guide treatment with use of modern spinal fixation methods.

The Ponte procedure: posterior only treatment of Scheuermann's kyphosis using segmental posterior shortening and pedicle screw instrumentation.

Study Design Case series. Objective To examine a consecutive series of surgically treated Scheuermann kyphosis that had a posterior only procedure with segmental pedicle screw fixation and segmental Ponte osteotomies. Summary of Background Data The gold standard for surgical treatment of Scheuermann kyphosis (a rigid kyphosis associated with wedged vertebral bodies occurring in late childhood or adolescence) has been combined anterior and posterior approach surgery. Alberto Ponte has advocated a posterior-only procedure with posterior column shortening via segmental osteotomies, but his procedure has not been widely accepted owing to concerns that without anterior column support there would be a risk of correction loss and/or instrumentation failure. With the advent of improved spinal instrumentation and fixation with thoracic pedicle screws, the Ponte procedure may offer an advantage over anterior/posterior reconstruction. Methods The study prospectively enrolled 17 consecutive patients with Scheuermann kyphosis who were treated with the Ponte procedure by the senior surgeon at one institution. Standardized radiographic analysis was performed and included full-length coronal and sagittal radiographs preoperatively, postoperatively, and at final follow-up. Analysis also included the correction obtained through the most severe, wedged segments of the deformity by the osteotomies. Results Seventeen patients had the Ponte procedure satisfactorily performed. No patient needed an anterior approach to achieve sufficient correction or fusion. There were no reoperations for nonunion or instrumentation failure. Correction of the instrumented levels was 61% and of worst Cobb was mean 49%. The apex of the deformity was measured over the most deformed 3 to 7 wedged segments. The average correction across the apex was 9.3 degrees per osteotomy (range 5.9 to 15). No patient lost more than 4 degrees of correction through their instrumented and fused levels. There were no neurologic complications. There was one late infection with a solid fusion treated with instrumentation removal and intravenous antibiotics. Conclusions Using thoracic pedicle screw instrumentation as the primary anchor, the Ponte procedure was successfully performed in 17 consecutive patients for Scheuermann kyphosis with no exclusions for the size or rigidity of the kyphosis. Results were as good as anterior/posterior historical controls with excellent correction and minimal loss of correction at final follow-up. This procedure avoids the morbidity and extended operative time attributed to the anterior approach. Level of Evidence Therapeutic study, level IV [case series (no, or historical, control group)].

Anterior and Posterior Spinal Fusion Staged Versus Same-day Surgery

Seventy-five patients who underwent combined anterior and posterior spinal fusion were compared to evaluate the results and safety of staged vs. continuous anterior and posterior spinal fusion. Thirty-five patients underwent two-stage anterior and posterior spinal fusion. The first stage consisted of anterior release; the second stage, which took place 7–10 days later, consisted of posterior spinal fusion and instrumentation. Forty patients underwent continuous anterior and posterior spinal fusion. This procedure consisted of anterior release followed by immediate posterior spinal fusion and instrumentation. The results show that 1) a continuous procedure is faster than the staged procedure; 2) there is less blood loss; 3) fewer days are spent in the hospital; and 4) better correction of the spinal deformity is achieved. Also, the complications were less frequent and less severe with the continuous procedure. It was concluded that the continuous procedure is safe and efficacious and has several advantages over the staged procedure.

Multisurgeon Assessment of Surgical Decision-Making in Adolescent Idiopathic Scoliosis : Curve Classification, Operative Approach, and Fusion Levels

Study Design. A multisurgeon assessment of curve classification, selection of operative approach, and fusion levels via a case study presentation. Objectives. To evaluate the ability of a group of scoliosis surgeons, not involved in the development of a new classification system, to accurately choose the corresponding curve classification of adolescent idiopathic scoliosis (AIS) cases and to evaluate the variability in the selection of operative approaches and both proximal and distal fusion levels in accordance with the new classification system in operative adolescent idiopathic scoliosis. Summary of Background Data. Recent evaluations using the King method for classifying AIS has shown poor intraobserver and interobserver reliability. A new, comprehensive classification system of AIS has been developed, but the result of a scoliosis surgeon’s ability to apply the objective classification is unknown. In the surgical treatment of AIS, there are three choices for the operative approach (anterior, posterior, or both) and multiple choices for the selection of fusion levels. Methods. During an AIS roundtable discussion at a spinal surgery meeting, 28 scoliosis surgeons were presented seven cases of operative AIS via good quality slides. Standard preoperative radiographs and clinical photographs were presented, and the reviewers were asked to classify the cases by a new classification system, choose their preferred surgical approach, and classify both proximal and distal fusion levels. Results. For the seven cases presented, 84% of the curve types, 86% of lumbar modifiers, and 90% of sagittal thoracic modifiers were classified by the reviewers as described in the new classification. The case study found widely variable operative approaches and fusion levels chosen by the reviewers. There was an average of five different proximal (range, 4–8) and four different distal (range, 3–5) fusion levels chosen by the reviewers for each case. Conclusions. This case study assessment found a relatively high rate (84–90%) of agreement in curve classification of the individual components of a new classification system of AIS. This suggests the ability of a group of scoliosis surgeons to identify the specific criteria necessary for this new classification system of AIS. In addition, the high variability in selection of both operative approach and fusion levels confirms the current lack of standardized treatment paradigms. This further reinforces the need for a method to critically and objectively evaluate these variable treatments to determine the “best” radiographic and clinical results.

Radiation exposure during pedicle screw placement in adolescent idiopathic scoliosis : Is fluoroscopy safe?

Study Design. With institutional review board approval, prospective data were collected during fluoroscopically guided pedicle screw placement. Objective. To estimate a surgeon’s radiation exposure with all screw constructs during surgery to repair idiopathic scoliosis. Summary of Background Data. To our knowledge, there is no established consensus regarding the safety of radiation exposure during fluoroscopically guided procedures. Methods. A surgeon was outfitted intraoperatively with a thermoluminescent dosimeter to estimate radiation exposure to his whole body and thyroid gland. Results. The index surgeon is projected to receive 13.49 mSv of whole body ionizing radiation and 4.31 mSv of thyroid gland irradiation annually. The National Council on Radiation Protection’s current recommendations set lifetime dose equivalent limits for classified workers (radiologists) at 10 mSv per year of life and at 3 mSv for nonclassified workers (spinal surgeons). At the levels estimated, a surgeon beginning his/her career at age 30 years would exceed the lifetime limit for nonclassified workers in less than 10 years. The National Council on Radiation Protection limits the single-year maximum safe dosage to the thyroid to 500 mSv; the yearly exposure estimated here is significantly less. Conclusions. The spinal surgeon’s intraoperative radiation exposure may be unacceptable. Spinal surgeons should be considered classified workers and monitored accordingly. Methods to lower radiation dosage seem strongly indicated.

Operative management of Scheuermann's kyphosis in 78 patients: Radiographic outcomes, complications, and technique

Study Design. A retrospective multicenter review of 78 patients with Scheuermanns kyphosis treated operatively was conducted. Objective. The purpose of this study was to evaluate correction of sagittal alignment, maintenance of correction, and occurrence of, and etiologic factors associated with, junctional kyphosis in patients managed operatively for Scheuermanns kyphosis. Summary of Background Data. There is a paucity of literature regarding the surgical treatment of Scheuermanns kyphosis using current implant systems and operative techniques. Junctional kyphosis has been shown to occur in up to one third of patients. Factors causing junctional kyphosis have not been clearly elucidated. Loss of correction has been variable based on the technique used. No clear-cut advantages or disadvantages have been shown for the use of anterior release. Methods. Kyphosis, lordosis, C7 sagittal plumbline, apical translation, junctional sagittal alignment, and pelvic incidence were assessed among other radiographic parameters from a centralized database. The incidence of junctional kyphosis and its association to the above parameters and to fusion levels were assessed. Complication rates and differences between patients undergoing combined anteroposterior surgery and those having posterior surgery alone were evaluated. Results. Of the 78 patients, 42 underwent combined anteroposterior procedures (Group 1) and 36 had posterior surgery only (Group 2). Mean age was 16.7 years. Overall, the greatest Cobb kyphosis of 78.8° was corrected to 51.4° at follow-up. Preoperative kyphosis was 82.6° and 74.4° for Groups 1 and 2, respectively (P < 0.001) and 55.8° and 46.2° at follow-up (P = 0.000). Loss of correction was 3.2° (not significant) and 6.4° (P = 0.000), respectively. Lordosis corrected from −65.5° to −51.7°.Proximal and distal junctional kyphosis of ≥10° occurred in 25 (32.1%) and 4 (5.1%), respectively. The development of a proximal junctional kyphosis correlated directly with kyphosis at follow-up and indirectly with percent correction. Among patients with proximal junctional kyphosis, the magnitude of junctional kyphosis correlated directly with the degree of pelvic incidence. Pelvic incidence correlated directly with lumbar lordosis but not kyphosis. Twelve complications occurred in 12 patients, including posterior wound infection (1), distal (2), and proximal (1) junctional kyphosis, and pseudarthrosis (1), those requiring reoperation. Conclusion. This is one of the largest reported series of Scheuermanns kyphosis treated operatively to our knowledge. A high rate of junctional kyphosis, especially at the proximal end, is associated with surgery for Scheuermanns kyphosis using current techniques. Proximal junctional kyphosis is associated with higher magnitude of kyphosis at follow-up, less percent correction; its magnitude correlated directly with pelvic incidence. Loss of correction is less in patients undergoing combined anteroposterior surgery. Pelvic incidence correlates directly with lordosis but not kyphosis, suggesting that these parameters are not causative of Scheuermanns kyphosis.

The posterior approach for lumbar and thoracolumbar adolescent idiopathic scoliosis: posterior shortening and pedicle screws.

Study Design. Prospective clinical case series. Background Data. Lumbar and thoracolumbar adolescent idiopathic scoliosis has traditionally been treated with an anterior approach and instrumentation. This anterior method often has had problems with kyphosis, pseudarthrosis, and loss of correction. The senior author has had good results treating these same lumbar and thoracolumbar curves posteriorly with wide posterior release and segmental instrumentation. In this series of his evolving technique, he adds pedicle screws as the sole anchor in the thoracolumbar/lumbar curves. Objectives. To prospectively evaluate outcomes, coronal and sagittal radiographic results, balance parameters, complications, and reoperations in a group of consecutive patients with lumbar and thoracolumbar adolescent idiopathic scoliosis. These patients were surgically treated with wide posterior release and segmental posterior screw instrumentation with 2-year minimum follow-up (range 26–47 months). Methods. Sixty-two consecutive patients with thoracolumbar and lumbar adolescent idiopathic scoliosis were treated with a wide posterior release and segmental pedicle screw instrumentation limited to the curve defined by the Cobb measurement. The patients were evaluated clinically and radiographically at intervals up to 36 months. There was 2-year minimum follow-up. Results. One patient was lost to follow-up. Of the remaining 61 patients, there were 51 Lenke 5 Type curves, 7 Lenke Type 3C curves, and 3 Lenke Type 6 curves. Only the curve defined by the Cobb measurement was fused. A total of 613 pedicle screws were placed safely. Average coronal correction of the thoracolumbar/lumbar curves was from 52° to 10° (80%). In the sagittal plane, lumbar lordosis was normalized from 41° with a wide range (20°–70°) to 42° with a normal range (34°–47°). There were no pseudoarthroses, no reoperations, no infections, no problems with screw placement, and excellent maintenance of correction at last follow-up. The lowest instrumented vertebrae had 81% correction of coronal angulation, center sacral line to lowest instrumented vertebrae was improved from 2.4 cm to 0.7 cm, and apex to center sacral line was improved from 5.2 cm to 1.5 cm. The C7 plumb line to center sacral line was also improved from 2.5 cm to 0.6 cm, illustrating the centering of the trunk. Conclusions. Wide posterior release and segmental pedicle screw instrumentation has excellent radiographic and clinical results with minimal complications. There were no pseudoarthroses and no reoperations.

Parents' and Patients' Preferences and Concerns in Idiopathic Adolescent Scoliosis : A Cross-Sectional Preoperative Analysis

Study Design. A multicenter cross-sectional study of parents’ and patient’s concerns and preferences regarding surgery for idiopathic scoliosis. Objectives. The purpose of this study was to analyze independently both the parents’ and patients’ assessments of upcoming surgery for idiopathic scoliosis. Summary of Background Data. No group has recently reported querying patients and their parents regarding expectations, preferences, reasons, and concerns about and for surgical treatment of adolescent idiopathic scoliosis. Methods. Ninety-one sets of parents and patients were separately asked to complete questionnaires regarding the patients’ upcoming idiopathic scoliosis surgery. Patients’ ages ranged from 9 to 18 years, and data were collected from four centers and seven surgeons (all active members of the Scoliosis Research Society) from April through December 1998. Thirty-nine questions covered concerns (n = 6), reasons for surgery (n = 14), expectations (n = 9), assessment of life as is (n = 5), and scar preference (n = 5). Results. The greatest concern about the surgery expressed by both parents and patients was neurologic deficit. The least concern for both was location and appearance of the scar. The highest expectation and main reason for having the surgery was to reduce future pain and disability as an adult. Families would be either somewhat or very dissatisfied to spend the rest of life “as is.” Conclusion. Although parents and patients had similar ratings and concerns, the parents’ concerns were higher, and expectations were greater than the patients’.