Clinical outcome and radiographic results after operative treatment of Scheuermann's disease

The aim of this prospective study was to evaluate radiographic findings, patient satisfaction and clinical outcome, and to report complications and instrumentation failure after operative treatment of Scheuermann's disease using a combined anterior and posterior spondylodesis. The loss of sagittal plane correction after removal of the posterior instrumentation was analysed. The indication for surgery was a thoracic kyphosis greater than 60 degrees in adolescents and adults with persistent back pain, which failed to respond to conservative treatment. Thoracic kyphosis and lumbar lordosis angles were measured by the Cobb method at preselected time points and at final follow-up. Sagittal plane alignment was measured as translation. The validated Scoliosis Research Society Instrument (SRSI) questionnaire was sent to all patients at follow-up. P-values were calculated using the Wilcoxon signed rank test (P<0.05 is significant). Between October 1987 and August 1999, 23 consecutive patients underwent operative treatment. The median follow-up was 75 months (range 25-126 months). Median preoperative thoracic kyphosis was 70 degrees (range 62 degrees-78 degrees) and median preoperative lumbar lordosis was 68 degrees (range 54 degrees-84 degrees). Immediate postoperative median thoracic kyphosis was 39 degrees (range 28 degrees-54 degrees) (P<0.05) and immediate postoperative median lumbar lordosis was 49 degrees (range 35 degrees-63 degrees) (P<0.05). These significant corrections were maintained at early follow-ups conducted 1 year and 2 years postoperatively. At final follow-up, the median thoracic kyphosis had significantly increased, to 55 degrees (range 36 degrees-65 degrees) (P<0.05 relative to immediate postoperative value), and the median lumbar lordosis had increased to 57 degrees (range 44 degrees-70 degrees) (P<0.05). The late deterioration of correction in the sagittal plane was mainly caused by removal of the posterior instrumentation, and occurred despite radiographs, bone scans and thorough intra-operative explorations demonstrating solid fusions. The median SRSI score was 83 points (range 55-106). There was no significant correlation between the radiographic outcome and the SRSI score (P>0.05). Our series showed relatively fair outcome after operative treatment in Scheuermann's disease. Therefore, the indication for surgery in patients with Scheuermann's disease can be questioned.     

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.     

Surgical treatment of scoliosis using allograft bone from a regional bone bank

Introduction

Routine spinal fusion techniques have involved removal of all soft tissues and articular facets, decortication of all posterior elements, and application of bone graft to the fusion area. Bone grafting has been performed mainly using the patient’s own bone (autograft bone), most commonly from the iliac crest. The use of autograft bone is accompanied by complications or problems because of harvesting and donor-site morbidity. Several studies have already reported the use of allograft bone in scoliosis surgery. However, these studies are small series with short-term follow-up.

Method

Twenty-two patients with scoliosis who underwent posterior spinal fusion and pedicle-screw-alone fixation using banked allograft bone obtained from the regional bone bank in Japan were analyzed. The average age at surgery was 13 years 5 months. The average follow-up was 2 years 7 months, and the average age at the last follow-up was 15 years 6 months. Scoliosis curves were divided into two groups (single curve group and double curve group).

Results

For the single curve group, the average preoperative coronal curve measured 78° (48°–85°) and the postoperative curve measured 22° (8°–35°), with no loss of correction at the last follow-up. For the double curve group, the average preoperative thoracic curve measured 64° (48°–85°) and the lumbar curve measured 42° (38°–60°). The average postoperative thoracic curve measured 12° (8°–34°) and lumbar curve measured 15° (8°–32°), with no significant loss of correction at the last follow-up. No patients had clinical complaints in the region of surgery at 9 months after surgery and thereafter. There were no complications including loss of correction, nonunion, infection and instrumentation failure. At the last follow-up, patients/parents were interviewed and asked to complete an outcome satisfaction questionnaire. They were asked to rate the outcome as very satisfactory, satisfactory, neither satisfactory nor unsatisfactory, unsatisfactory, or very unsatisfactory. Seventeen patients (77%) were very satisfied, four patients (17%) were satisfied, and one patient (6%) was neither satisfied nor unsatisfied. Autograft bone and banked allograft bone appear to yield comparable results and clinical outcomes.

Conclusion

However, in Japan, various expenses accrue to supply a safe and premium quality of banked allograft bone. Financial issue must be resolved as soon as possible.     

Selective ventral derotation spondylodesis in idiopathic thoracic scoliosis: a prospective study

AIM: Radiometric curve analysis of instrumented primary and spontaneous secondary curve correction after anterior correction and fusion of idiopathic thoracic scoliosis. METHOD: Sixty-four patients with idiopathic thoracic scoliosis were prospectively evaluated. All patients were operated either with the Zielke-VDS or with a primary stable double rod instrumentation with selective fusion of the thoracic curve from end-to end-vertebra. Follow-up averaged 29 months (24 - 52 months). RESULTS: The Cobb angle of the primary curve averaged 63.2 degrees preoperatively and was corrected to 21.4 degrees postoperatively with an average loss of correction of 5.3 degrees (58 % final curve correction). Apical thoracic vertebral rotation was corrected by 48 %. The secondary lumbar curve measured 38.2 degrees preoperatively (72 % correction on the bending films) and was spontaneously corrected by 57 % to 16.4 degrees without significant loss of correction in the final follow-up. Apical vertebral rotation averaged 11.3 degrees in the lumbar curve and was corrected spontaneously by 24 % to 8.6 degrees without significant loss of correction. Lumbar apex vertebra deviation showed no significant reduction. There was no case of lumbar curve decompensation in either frontal or sagittal plane. Implant related complications were observed in 7 patients (rod breakage), but no pseudarthrosis occurred. There were no neurological complications noted. CONCLUSION: Selective anterior correction and fusion in idiopathic thoracic scoliosis enables a satisfactory correction of both primary and lumbar secondary curves. The advantage of selective anterior correction and fusion of thoracic scoliosis is the short fusion length, better derotation and satisfactory correction of the secondary lumbar curve. The disadvantages of single threaded rod techniques in terms of lack of primary stability and a kyphogenic effect have been eliminated by the development of a primary stable, small size double rod instrumentation.     

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.     

Results of surgical treatment for kyphotic deformity of the spine secondary to trauma or Scheuermann's disease

The authors have performed a retrospective study of 20 patients who underwent surgical treatment for kyphosis secondary to trauma (10 patients) or Scheuermann's disease (10 patients) between 1992 and 2000. The mean follow-up was 60 months (range, 32-90) and 59.5 months (range, 24-109) respectively. Radiological evaluation of Scheuermann kyphosis included assessment of thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), scoliosis angle (SA) and sagittal vertical axis (SVA); radiological evaluation of post-traumatic kyphosis included the determination of local kyphosis angle (LKA) and SA, if present. A posterior approach was performed in 6 cases and a combined anterior and posterior approach was performed in 4 cases of SD whereas patients with post-trauma kyphosis were treated using an anterior approach in one case, a posterior approach in another and a combined anterior and posterior approach in 8 cases. The mean TKA in Scheuermann cases was 71 degrees (65 degrees-80 degrees) preoperatively and 41 degrees (31 degrees-52 degrees) postoperatively. There was a mean loss of correction of 5 degrees. No positive sagittal balance was present during follow-up. The mean TKA in post-trauma cases was 38 degrees (25 degrees-62 degrees) pre-operatively and 14 degrees (range -15 degrees-28 degrees) postoperatively. At the last visit, the mean loss of correction was 2 degrees. Proximal junctional kyphosis developed in two cases with Scheuermann kyphosis (17 degrees and 13 degrees) and in one case with post-traumatic kyphosis (17 degrees). These findings show that good results can be achieved in the treatment of kyphosis secondary to trauma or Scheurmann's disease, with appropriate selection of the surgical approach.     

Posterior spinal fusion: allograft versus autograft bone

The effectiveness of allograft bone for posterior spinal fusion in neuromuscular scoliosis is controversial. Thirty patients with cerebral palsy, treated with posterior spinal fusion, were divided into two groups. Group 1 consisted of 18 patients treated by posterior spinal fusion using autogenous bone graft. Group 2 consisted of 12 patients treated by posterior spinal fusion using freeze-dried allograft bone. The average preoperative curve of 70 degrees in Group 1 was corrected to 35 degrees (50% correction). At 3.2 years average follow-up, the curves averaged 51 degrees (46% loss of correction). The average preoperative curve of 80 degrees in Group 2 was corrected to 39 degrees (51% correction). At 3.5 years average follow-up, the curves averaged 54 degrees (38% loss of correction). Anesthesia time decreased from 344 to 281 minutes (p less than 0.05), and intraoperative blood loss decreased from 2730 to 1740 ml (p less than 0.025) when allograft bone was used as a substitute for autograft bone. Freeze-dried allograft bone is a readily available, safe, and effective substitute for autogenous bone graft in patients with cerebral palsy undergoing posterior spinal fusion.     

Surgical treatment of Scheuermann's disease with segmental compression instrumentation

Twenty-one patients with Scheuermann's kyphosis had surgery for progressive kyphotic deformity of 50 degrees or greater. There were six adolescents, with a mean age of 15.6 years (range, 13-17 years) and 15 young adults, with a mean age of 25.4 years (range, 18-40 years). All patients had posterior spine arthrodesis with segmental compression instrumentation. Seven patients with rigid kyphosis had combined anterior and posterior spine arthrodesis. One patient died of superior mesenteric artery syndrome. In the group of 13 patients with posterior arthrodesis only, followup was 4.5 years. The mean preoperative thoracic kyphotic curve of 68.5 degrees improved to 40 degrees at latest review, with an average loss of correction of 5.75 degrees. Junctional kyphosis occurred in two patients with a short arthrodesis: one at the cephalad end and one at the caudal end of the fused kyphotic curve. In the second group of seven patients with combined anterior and posterior arthrodesis, followup was 6 years. The mean preoperative thoracic kyphotic curve of 86.3 degrees improved to 46.4 degrees at latest review, with an average loss of correction of 4.4 degrees. Overall, there was no postoperative neurologic deficit and no pseudarthrosis. Thus, posterior arthrodesis and segmental compression instrumentation seems to be effective for correcting and stabilizing kyphotic deformity in Scheuermann's disease. Despite a long operating time, this technique provided significant correction, avoiding the development of any secondary deformity in most patients. Combined anterior and posterior spine arthrodesis is recommended for rigid, more severe kyphotic deformities.     

Thoracic scoliosis fusion in adolescent and adult idiopathic scoliosis using posterior translational corrective techniques (Isola): is maximum correction of the thoracic curve detrimental to the unfused lumbar curve?

BACKGROUND CONTEXT: Postoperative coronal decompensation in selective thoracic fusion was reported with derotation maneuvers when using the Cotrel-Dubousset (CD) system. Isola instrumentation is a multiple anchor system that corrects spine deformity with segmental vertebral translation to a predetermined contoured longitudinal member. PURPOSE: To evaluate the efficacy of translational corrective techniques using Isola instrumentation in thoracic fusion for adolescent and adult idiopathic scoliosis patients. STUDY DESIGN/SETTING: This is a retrospective review of adolescent and adult patients with idiopathic scoliosis who underwent posterior thoracic fusion using translational corrective techniques with Isola instrumentation. PATIENT SAMPLE: Twenty-two patients (14 adolescents with idiopathic scoliosis, 8 adults with scoliosis) who underwent posterior thoracic fusion using translational corrective techniques were evaluated. OUTCOME MEASURES: The charts, radiographs and self-assessment questionnaire were reviewed. METHODS: Comparative analysis was done between patients who had Lenke Type A curves (Group 1) and Lenke Type B or C curves (Group 2) for both adolescent and adult scoliosis groups. RESULTS: The mean follow-up was 54 months (range, 33 to 80 months). The mean preoperative Cobb angle of thoracic and lumbar curves in all 22 patients was 48 degrees (range, 34 to 64 degrees) and 31 degrees (range, 20 to 46 degrees), respectively. Postoperative measurements were 16 degrees (range, 0 to 28 degrees) for thoracic and 13 degrees (range, 2 to 25 degrees) for lumbar (67% thoracic and 60% lumbar correction) in Group 1, and 19 degrees (range, 1 to 33 degrees) for thoracic and 12 degrees (1 to 21 degrees) for lumbar at latest follow-up (61% thoracic and 61% lumbar correction) in Group 2. There was no difference in the final correction of the lumbar curves between Groups 1 (64%) and 2 (58%), although the Cobb angle in Group 2 was larger. Radiographic coronal decompensation occurred in only one patient in Group 2, who remained asymptomatic and required no further treatment. Clinical outcome assessment showed 100% satisfaction (n=15), 92% relief of symptoms (n=13) and 92% improvement of activities in both groups. CONCLUSIONS: Fusion of the major thoracic curve using translational corrective technique (Isola) in patients with idiopathic scoliosis is an effective procedure that achieves high patient satisfaction while providing excellent correction of both the thoracic and lumbar curves. Unlike rotational corrective techniques (CD), clinical decompensation requiring further treatment did not occur in any patient treated with this method.     

Radiographic outcomes using freeze-dried cancellous allograft bone for posterior spinal fusion in pediatric idiopathic scoliosis

The senior author (A.G.) has gained extensive experience using freeze-dried cancellous allograft chips to obtain solid posterior fusion in patients with adolescent idiopathic scoliosis. The purpose of this study is to determine whether this form of allograft bone will yield successful fusion rates and maintain a minimal loss of curve correction when combined with current segmental posterior spinal instrumentation systems. Radiographs of 55 patients were evaluated by two masked reviewers using a previously devised grading system. At an average follow-up of 39 months (minimum 24 months), the overall fusion rate was 92.7% and the loss of curve correction was 3.4 degrees. The results of this study show that freeze-dried allograft chips yield successful fusion rates and only minimal loss of curve when combined with current posterior spinal instrumentation systems in patients with pediatric idiopathic scoliosis.     

Radiographic evaluation of selective anterior thoracolumbar or lumbar fusion for adolescent idiopathic scoliosis

According to Lenke classification of adolescent idiopathic scoliosis (AIS), patients with type 5 curve in which the structural major curve is thoracolumbar or lumbar curve with nonstructural proximal thoracic and main thoracic curves, could be surgically treated with selective anterior thoracolumbar or lumbar (TL/L) fusion. This study retrospectively analyzed the radiographies of selective anterior TL/L fusion in 35 cases of AIS with Lenke type 5 curve. Segmental fixation with a single rigid rod through anterior thoracoabdominal approach was applied in all patients. Measurements of scoliosis curve in preoperative, immediate postoperative and follow-up radiographies were analyzed. The average follow up time was 36 months (24-42 months). The average preoperative Cobb angle of the TL/L curve was 45.6 degrees and improved into 9.7 degrees immediate postoperatively, with 79.7% curve correction. In addition, the minor thoracic curve decreased from 29.7 degrees preoperatively to 17.6 degrees postoperatively, with a spontaneous correction of 41.5%. During the follow-up, a loss of 4.6 degrees correction was found and the average Cobb angle of TL/L increased to 14.4 degrees . Also, the minor thoracic curve increased to average 20.1 degrees with a loss of 2.4 degrees correction. Trunk shift deteriorated slightly immediate postoperatively and improved at the follow-up. The lowest instrumented vertebra (LIV) tilt was improved significantly and maintained its results at the follow-up. During the follow-up, the coronal disc angle immediately above the upper instrumented vertebra (UIVDA) and below the LIV (LIVDA) aggravated, while the sagittal contours of T5-T12 and T10-L2 were well maintained. The lumbar lordosis of L1-S1 and the sagittal Cobb angle of the instrumented segments were reduced slightly postoperatively and at the follow-up. There were no major complications or pseudarthrosis. The outcomes of this study show that selective anterior thoracolumbar or lumbar fusion with solid rod instrumentation is effective for surgical correction of AIS with Lenke type 5 curve. The TL/L curve, minor thoracic curve, and LIV title can be improved significantly, with good maintenance of sagittal contour. However, the UIVDA and LIVDA aggravate postoperatively when the trunk rebalances itself during follow-up. The degeneration of LIV disc warrants longer-term follow-up.     

Surgical treatment of idiopathic scoliosis with anterior dual rod instrumentation

BACKGROUND: In the surgical treatment of idiopathic scoliosis both anterior and posterior correction and instrumentation techniques are available. The aim of the present study was to analyse the results of a new anterior dual rod instrumentation. PATIENTS AND METHODS: Prospective analysis of radiometric and clinical parameters of 93 patients operated on between 1996 and 2004 using the Münster Anterior Dual Rod System. RESULTS: The average curve correction was 65% (fusion length usually Cobb levels) with a preoperative Cobb angle of 59 degrees. Postoperative loss of correction amounted to 1.5 degrees (average follow-up of 36 months). Apical vertebral derotation averaged 45% in the thoracic and 53% in the lumbar spine with a subsequent correction of the rib hump of 66% and the lumbar hump of 81%. There were no revisions or neurological complications. CONCLUSION: Anterior dual rod instrumentation enables an effective and safe three-dimensional curve correction in single structural curves with only minimal loss of correction.     

Osteotomy for kyphosis in ankylosing spondylitis

Twenty-two patients suffering from progressive kyphosis due to ankylosing spondylitis underwent one or more lumbar osteotomies during 1957-1983. The primary thoracic kyphosis was 80 degrees (45 degrees-155 degrees). The mean correction obtained by one level osteotomy was 44 degrees (30 degrees-60 degrees). The mean loss of correction after 3 years was 5 degrees. The use of internal fixation reduced the loss of correction from 9 degrees to 1 degree, also allowing ambulatory after-care and a shorter period of immobilization in plaster or jackets. We had no fatal and relatively few non-fatal complications; three cases of retrograde ejaculation were observed however. All the patients reported subjective respiratory improvement.     

A long-term follow-up study of anterior tibial allografting and instrumentation in the management of thoracolumbar tuberculous spondylitis

OBJECT: The purpose of this study was to determine the efficacy of anterior instrumentation following radical debridement and tibial allografting and its long-term progression in patients with multilevel spinal tuberculosis. METHODS: This prospective observational study was undertaken to analyze 22 patients with multilevel spinal tuberculosis (Pott disease) who underwent anterior radical debridement, decompression, and fusion using anterior spinal instrumentation and tibial allograft replacement between 1999 and 2001. Clinical outcomes were assessed using the American Spinal Injury Association (ASIA) Impairment Scale and a visual analog scale (VAS). Preoperative and postoperative plain radiographs were obtained, and the focal kyphotic angle of the surgically treated spinal segments and the overall sagittal and coronal contours of the thoracic and lumbar spine were evaluated in all patients. RESULTS: The mean follow-up time was 84 months (range 36-96 months). All patients demonstrated clinical healing of the tuberculosis infection. All patients showed evidence of successful bone fusion. The mean late postoperative kyphosis correction was 74% (range 63-91%). On average, 2 degrees (range 0-5 degrees ) of loss of correction was noted in the local kyphotic angle postoperatively in late follow-up findings. Evaluation of the surgical effect on sagittal global contours showed a significant correction rate in thoracic, thoracolumbar, and lumbar regions. The mean late postoperative coronal plane alignment correction was 99%. The ASIA Impairment Scale scores demonstrated significant improvement in late follow-up results in our series. Surgical decompression also resulted in a dramatic reduction of overall pain in all patients (late postoperative VAS score 1.61 +/- 0.81). CONCLUSIONS: Anterior tibial allografting and instrumentation provide correction of the curvature, prevention of further deformation, improvement of sagittal and coronal balance, and restoration of neurological function in patients with spinal tuberculosis.     

The selection of fusion levels using torsional correction techniques in the surgical treatment of idiopathic scoliosis.

STUDY DESIGN: This is a retrospective, consecutive case series, with the index patient included. OBJECTIVES: To evaluate the evolution and effectiveness of instrumentation techniques designed to untwist the scoliosis deformity. SUMMARY OF BACKGROUND DATA: Three-dimensional studies of the idiopathic scoliosis deformity are consistent with the theory that the deformity or deformities evolve as an imperfect torsion or torsions. METHODS: From 1989 through 1995, 102 consecutive patients (84 females, 18 males) underwent surgery with increasing emphasis on torsional correction. One hundred patients (98%), with an average age of 14.3 years (range, 10.5-20.8 years), were observed for an average of 40 months (range, 24-81 months). The upper instrumented vertebra evolved to be the centered vertebra. The lower instrumented vertebra was chosen based on its ability to become horizontal on contralateral bend radiographs and was termed the caudal foundation vertebra. Because these techniques evolved over the first 3 years of the study period, a split analysis was performed to evaluate improvements in correction and correction maintenance over the course of the study. RESULTS: The average Cobb angle was 59 degrees before surgery, 18 degrees after surgery (69% correction), and 22 degrees (63% correction) at latest follow-up. A comparison of the first half of the series with the second half showed no significant demographic differences. Curve correction was significantly improved for King-Moe IIB (thoracolumbar-lumbar curve only), King-Moe III, and King-Moe V curve types in the second half of the series. In the last 4 years, curve correction at latest follow-up for King-Moe IIB curves was 61% for the thoracic curve and 65% for the thoracolumbar-lumbar curve. King-Moe III curves had a 68% correction, and King-Moe V curves had a 50% high thoracic and a 72% thoracic curve correction. Thoraco-lumbar, lumbar, and King-Moe I curves averaged 81% correction of the thoracolumbar-lumbar curve. The angle of thoracic curve inclination improvement at 1 year was maintained at latest follow-up. CONCLUSIONS: This method of selecting instrumentation levels while using torsional correction techniques is safe and reliable. The results were improved with the evolution of these techniques and appear to provide improved correction and correction maintenance compared with that of historical controls.     

The kinematic rotating hinge prosthesis for complex knee arthroplasty.

Fifty-eight patients (69 knees) treated with the Kinematic Rotating Hinged knee prosthesis for complex primary and salvage revision total knee arthroplasty were followed up for an average of 75.2 months (range, 24-199 months). The indications for use of the Kinematic Rotating Hinged knee prosthesis included severe bone loss combined with ligamentous instability (30 knees), nonunion of a periprosthetic fracture (10 knees), an acute periprosthetic fracture (nine knees), severe collateral ligamentous instability (five knees), reimplantation for infection (six knees), nonunion of a supracondylar femoral fracture (four knees), congenital dislocation of the knee (three knees), and treatment of a severely comminuted distal femur (two knees). At the time of surgery, the average patient age was 72 years (range, 46-92 years). Preoperatively, knee extension averaged 4.94 degrees (range, 0 degrees-40 degrees) and flexion averaged 81 degrees (range, 15 degrees-125 degrees). At final followup, knee extension averaged 1.25 degrees (range, -5 degrees-25 degrees) and flexion averaged 94.2 degrees (range, 5 degrees-125 degrees). The preoperative Knee Society Knee score averaged 40.3 points (range, 2-93 points) and improved to 77 points (range, 33-99 points) at final followup. Complications were numerous: 23 (32%) patients experienced at least one complication and 12 (17%) patients had two or more complications. Deep periprosthetic infection was the most common complication (14.5%), followed by patellar complications (13%), and prosthetic component breakage (10%). During the period of this study, there were 15,798 primary and 2673 revision total knee arthroplasties done at the authors' institution. The patients receiving a Kinematic Rotating Hinged knee prosthesis represent a highly complex and small subset (0.37%) of the overall population having knee arthroplasty. Although the use of the Kinematic Rotating Hinged knee prosthesis for these limited indications has been useful for the authors, the incidence of complications and the poor outcome of these complications is disconcerting. Hinged total knee arthroplasty should be reserved for the final salvage option of the treatment options available when doing complex primary and salvage revision knee arthroplasties.     

The use of 'hybrid' allografts in the treatment of fractures of the thoracolumbar spine: first experience

Harvesting autogenous bone grafts of the iliac crest carries complications and lengthens operative times. Allografts are preferred to avoid these problems. Fusion after using allogenic bone grafts has been well studied, by examining trabeculations and remodelling on anteroposterior and lateral radiographs. However, the question remains whether one can rely on radiographs alone to determine fusion. 'Hybrid' fresh-frozen allografts from the femur or tibia were used in 11 adult patients with a mean age of 56.4 years (range: 30-78 years) to stabilize the thoracolumbar spine after anterior decompression for trauma. In one case two adjacent levels were fractured, in another case two fractures occurred at different levels. Fresh-frozen allografts of the femur (in ten cases) and tibia (one case), filled with autogenous cancellous bone graft or pieces of rib, were used to reconstruct the anterior column of the spine. Stabilization was performed by means of a Kaneda device. Anteroposterior and lateral radiographs and, additionally, computed tomography (CT) examinations with reconstructions were used to study fusion. One patient died 1 month after surgery. At follow-up in ten patients, after a mean time of 30.2 months (range: 18-42 months), ten allografts showed a grade I fusion and one a grade III fusion. Additional data from the CT examination with reconstructions, however, showed cross-trabeculations in all cases, and a partially united allograft in the patient with a grade III fusion. Cross-trabeculations between the allograft and vertebral body was observed at 6 months, with remodelling occurring at approximately 2 years. Mean loss of correction was minimal, at 3.6 degrees (range 0 degree-16 degrees). Fresh-frozen femoral or tibial allografts worked effectively to maintain correction after trauma when combined with anterior instrumentation. CT examinations with sagittal and coronal reconstructions were more effective for evaluation of fusion compared with anteroposterior and lateral radiographs. The high fusion rate and the low morbidity achieved using allografts in this way supports the exclusive use of allografts in the anterior thoracic and lumbar spine in the future.     

Early experience and results with the periacetabular osteotomy. The Mayo Clinic experience.

The purpose of the present study was to review the early results of periacetabular osteotomy in the initial group of patients undergoing this procedure at the authors' institution. The first 21 hips in 19 patients with greater than 2 years followup, which represents the learning curve with this operation, were reviewed retrospectively. There were 14 females and five males with an average age of 21 years (range, 17-43 years). Intertrochanteric osteotomy was performed simultaneously on four patients with coxa valga and inadequate correction with periacetabular osteotomy alone. At an average of 38 months of followup (range, 24-52 months), the Mayo hip scores improved from an average of 46 points (range, 34-58 points) to an average of 68 points (range, 42-80 points). Hip range of motion declined slightly in all three arcs of motion. The lateral center edge angle of Wiberg improved from an average of 2 degrees to an average of 24 degrees. The loading zone angle (T?nnis) improved from an average of 24 degrees to an average of 11 degrees. The anterior center edge angle of Lequesne improved from an average of -6 degrees to an average of 38 degrees. Complications included two peroneal palsies, both of which resolved completely; three ischial fractures that healed uneventfully; three asymptomatic pubic nonunions; and asymptomatic heterotopic ossification in five patients. One patient underwent subsequent total hip arthroplasty for progressive arthritis and pain. Another patient required intertrochanteric osteotomy at a later date. The early results in this initial group of patients treated with periacetabular osteotomy show reliable radiographic correction of deformity and improved function with an acceptable complication rate. Patients should be counseled carefully about possible loss of motion postoperatively. Additional study is necessary to assess the long term results of this procedure.     

Reconstruction of the pelvis after tumor resection in children and adolescents

Thirty patients younger than 19 years with malignant bone tumors of the pelvis were treated by limb salvage surgery between 1970 and 1998. Functional and oncologic results were reviewed retrospectively. In 10 patients the defect was reconstructed by an endoprosthesis and in 20 patients reconstruction by autologous grafts (n = 7), allograft and prosthesis combinations (n = 2), bone cement reconstruction (n = 1), iliosacral arthrodesis (n = 1), modified Girdlestone procedure (n = 3), or resection without reconstruction (n = 6) was done. Three and one-half reoperations per patient were necessary postoperatively after allograft reconstruction, 2.5 reoperations per patient were necessary after endoprosthetic reconstruction, and 0.8 reoperations per patient were necessary after other or no reconstruction. After a mean followup of 52 months (range, 2-241 months), 17 patients were alive, 15 of whom were continuously disease-free, and 13 patients had died of their disease. Functional ratings were 81% after autograft, 73% after allograft, and 60% after endoprosthetic reconstruction. Defect reconstruction varied according to the type of resection. Type I resections were best reconstructed by biologic methods. Endoprosthetic reconstruction after periacetabular resection with the advantage of preservation of a functional hip and body integrity was associated with a high rate of complications and reoperations. Its role compared with allograft reconstruction, modified Girdlestone procedure, or no reconstruction requires additional investigation.     

TRAFIX内固定系统在特发性脊柱侧凸矫正中的临床应用

目的探讨TRAFIX内固定系统在脊柱侧凸矫正中的应用方法, 以提高脊柱侧凸矫正手术疗效. 方法自1997年10月始应用TRAFIX内固定系统对27例特发性脊柱侧凸患者实施矫正手术,其中女性20例,男性7例 ;平均年龄14岁(11～21岁).接受前路松解手术4例,第2次矫正手术1例.平均随诊时间26个月(13～37个月). 结果术前侧凸平均冠状面畸形为65°(42°～110°),术后矫正至29°(3°～64°),平均矫正率为55.4%,平均融合节段为11.5个(7～17个)椎体.主侧凸顶椎与第7颈椎(C7)垂线距离手术前后分别为52.1 mm(25～94 mm)和28.5 mm(4～62 mm). 结论 TRAFIX内固定系统对脊柱侧凸在三维平面同时产生矫正,特别表现为内置物精巧, 操作方便,固定可靠.