Lars Hackenberg

Clinical and Radiologic 2-4-Year Results of Transforaminal Lumbar Interbody Fusion in Degenerative and Isthmic Spondylolisthesis Grades 1 and 2

Study Design. Prospective clinical study. Objective. To evaluate the clinical and radiographic result of the transforaminal lumbar interbody fusion (TLIF) as an alternative new technique in degenerative and isthmic lower grade spondylolisthesis. Summary of Background Data. TLIF is a new alternative surgical technique used for spinal fusion avoiding the ventral approach and can theoretically prevent typical complications, such as those seen in anterior and posterior lumbar interbody fusion. Materials and Methods. There were 19 degenerative, 19 isthmic, and 1 dysplastic spondylolistheses operated on with TLIF. The clinical follow-up used the Oswestry Disability Index, the radiologic follow-up radiograph, analyzing segmental lordosis, intervertebral space, reduction, and fusion rate. The minimum follow-up was 24 months, mean clinical follow-up was 50 months, and radiologic follow-up was 35 months. Results. The medium of the Oswestry Disability Index in all patients decreased from 23.5 to 13.5 points, in isthmic spondylolistheses from 20.5 to 10.95 after 2 years. The radiographic fusion rate was 94.8%. The sagittal translation was reduced from 23% to 15%. There were 3 (7.6%) serious postoperative complications observed, which required operative revision. Conclusions. TLIF is a safe and effective method to treat low-grade spondylolisthesis, which can theoretically prevent typical complications of anterior and posterior lumbar interbody fusion. The results of isthmic spondylolistheses were significantly better compared to degenerative spondylolistheses.

Rasterstereographic back shape analysis in idiopathic scoliosis after posterior correction and fusion.

OBJECTIVE To determine the accuracy of rasterstereographic three-dimensional back surface analysis and reconstruction of the spine in idiopathic scoliosis treated by posterior correction and fusion. DESIGN Prospective imaging study of 25 patients with idiopathic scoliosis who underwent posterior correction and fusion and were followed for one year. BACKGROUND In an earlier study published in this journal rasterstereography has proved to be an accurate imaging modality for quantifying the changes in the three-dimensional shape of the spine and posterior rib cage after anterior correction and fusion. Goal of the present study was to determine the accuracy for the more common posterior correction and fusion with attention paid to the presence of the posterior implants and scarring. METHODS Twenty-five patients with idiopathic scoliosis with maximum Cobb angles of 78 degrees were examined by rasterstereography and radiography. Seventy-one anterior-posterior radiographs were digitised. Twenty-four were preoperative and 47 postoperative radiographs. Rasterstereographic and radiographic curves were compared by best-fit superimposition. Root-mean-square differences were calculated as parameters of accuracy. RESULTS The accuracy of rasterstereography in severe idiopathic scoliosis with Cobb angles between 48 degrees and 78 degrees was satisfactory with root-mean-square differences of 5.8 mm for the lateral deviation and 4.8 degrees for vertebral rotation. Following posterior correction the accuracy was good. The root-mean-square difference was 4.5 mm for the lateral deviation and 4.3 degrees for vertebral rotation. CONCLUSION The accuracy obtained for posteriorly-operated scolioses between 50 degrees and 80 degrees was similar to the findings for scolioses operated via anterior approach, as well as those with curves up to 50 degrees Cobb angle. Therefore rasterstereography can be used postoperatively to reduce the number of radiographs and radiation exposure. Additionally, the method provides an objective quantification of the postoperative improvement in the cosmesis of the back shape. RELEVANCE In the treatment of severe idiopathic scoliosis rasterstereography provides both a considerable reduction of X-rays and an objective documentation of the cosmesis before after scoliosis surgery.

Dual-rod correction and instrumentation of idiopathic scoliosis with the Halm-Zielke instrumentation

Study Design. A prospective clinical and radiographic evaluation of 45 consecutive patients with idiopathic adolescent and adult scoliosis treated with anterior dual-rod Halm-Zielke instrumentation. Objectives. Clinical and radiographic evaluation with a minimum follow-up of 2 years. Summary of Background Data. Halm-Zielke instrumentation was developed to eliminate the disadvantages of Zielke instrumentation in terms of lack of primary stability and a kyphogenic effect. Methods. All patients underwent an identical anterior surgical technique with the Halm-Zielke instrumentation of the primary curve. The system is composed of a lid-plate, which is fixed to the lateral aspect of the vertebral body with two screws: a sunk screw anteriorly and a ventral derotation spondylodesis (VDS) screw posteriorly. The lid-plate design provides the lowest possible implant profile. The longitudinal components consist of a threaded rod and a solid, fluted rod. Correction is performed with both the threaded and the solid rod. The solid rod allows derotation and correction of the sagittal plane and provides primary stability. Results. Preoperative curves ranged from 35° to 92° Cobb angle. Final correction of the frontal plane averaged 67% within the instrumented levels and 59% for the total primary curve. The apical vertebral rotation of the primary curve was corrected by 52% on average without loss of correction during follow-up. Thoracolumbar kyphosis was present in 11 patients and corrected in all cases from an average of 20° to 2° after surgery and to 8° at follow-up. We observed two cases of implant failure with one resulting in a pseudarthrosis. Conclusion. Halm-Zielke instrumentation proved to be a major improvement of the original VDS-Zielke. It eliminates the kyphogenic effect and provides primary stability.

Raster stereography versus radiography in the long-term follow-up of idiopathic scoliosis.

Study Design Raster-stereographic and radiographic evaluation of idiopathic scoliosis without braces in a retrospective longitudinal long-term follow-up study. Objective To investigate the reliability and accuracy of raster stereography in comparison with radiography as the gold standard, using a longitudinal long-term study design in idiopathic scoliosis, to reduce the number of radiographs required during follow-up in scoliosis patients. Summary of Background Data It has been confirmed that raster stereography produces reliable data in patients with conservatively and surgically treated idiopathic scoliosis, up to a Cobb angle of 80 degrees. This means that the method can be used to replace radiography during the follow-up in these patients. However, no data have yet been published on the use of raster stereography in a longitudinal setting during a long-term follow-up period in comparison with radiography as the gold standard. Methods Raster stereographs and digitized anterior-posterior radiographs of 16 patients with idiopathic scoliosis were studied retrospectively in a longitudinal study design, with a mean follow-up period of 8 years (range 3 to 10 y). Lateral vertebral deviation and vertebral rotation were measured between C7 and L4 using raster stereography and radiography, compared with Cobb angles, and correlated. Results During the follow-up period, the Cobb angle increased on average by 13 degrees. The progression of lateral vertebral deviation measured using both techniques, and that of vertebral rotation measured with radiography, was greater than that of the Cobb angle, whereas that of raster-stereographic vertebral rotation was lower. However, there was an excellent correlation between the raster-stereographic and radiographic progression of these parameters (R2≥0.5). The mean difference between raster stereographs and radiographs was 3.21 mm for lateral vertebral deviation and 2.45 degrees for vertebral rotation. Conclusions Using the parameters of lateral vertebral deviation and vertebral rotation, raster stereography accurately reflects the radiographically measured progression of idiopathic scoliosis during the long-term follow-up, but these parameters are not directly comparable with the Cobb angle. In the follow-up of scoliosis patients, the authors would recommend a raster-stereographic examination every 3 to 6 months and a radiographic examination every 12 to 18 months only, provided that raster stereography does not show rapid deterioration of the scoliosis. The patients radiation exposure can be reduced using this approach.

Spontaneous correction and derotation of secondary curves after selective anterior fusion of idiopathic scoliosis.

Study Design. Clinical, rasterstereographic, and radiographic evaluation of spontaneous vertebral derotation of secondary curves in idiopathic scoliosis following selective anterior correction and fusion of the primary curve. Objective. To quantify spontaneous vertebral derotation in secondary curves after selective anterior correction with attention to cosmetic outcome. Summary of Background Data. While the derotational effect of anterior instrumentation techniques on the instrumented curve is well understood, there is a paucity on data of the rotational behavior of the noninstrumented secondary curves. Methods. A total of 43 patients with idiopathic scoliosis (16 with thoracic curves in group 1 and 27 with thoracolumbar/lumbar curves in group 2) underwent selective anterior instrumentation. Vertebral rotation was analyzed before surgery and, on average, 20 months after surgery using digital radiometric rotation analysis, back shape analysis with rasterstereography, and scoliometer measurement. Results. In Group 1, there was a significant spontaneous vertebral derotation of the secondary lumbar curves by 14.2% (range from 12.7° to 10.9°) in the digital radiometric rotation analysis, surface derotation amounted to 49% (range from 9.6° to 4.9°) in the rasterstereography, and to 70% in the clinical scoliometer measurement (range from 8.0° to 2.4°). In group 2, there was an increase of rotation of the noninstrumented secondary thoracic curves by 30% (range from 5.0° to 6.5°) in digital radiometry, by 32.9% in the rasterstereography (range from 8.5° to 11.3°), and a 28.3% increase in scoliometer measurement (range from 6.0° to 7.7°). Conclusion. Selective anterior instrumentation and fusion of primary thoracic curves results in satisfactory spontaneous vertebral and high surface derotation of the secondary lumbar curves. However, in primary thoracolumbar or lumbar curves, an increase of both vertebral and surface rotation of the secondary thoracic curve was noted. This increase can impair cosmetic outcome.

Results of suture anchor repair of anteroinferior shoulder instability: A prospective clinical study of 85 shoulders

The results of an open Bankart procedure with use of suture anchors were evaluated in 85 shoulders in 83 patients. The mean age was 30 years (range, 16-59 years). The mean number of preoperative dislocations was 18.5. Patients were evaluated prospectively by the Rowe score. Eighty-five shoulders were followed for 1 year and seventy-seven for at least 2 years. The mean follow-up was 3.5 years (range, 1-8.3 years). The Rowe score increased from 30 to 92 points. An excellent or good result was found in 81 of 85 shoulders after 1 year and in 68 of 77 shoulders after 2 years. Seven redislocations occurred, four due to a new trauma. Two patients had recurrent subluxations, one due to a new trauma.

Rasterstereographic analysis of axial back surface rotation in standing versus forward bending posture in idiopathic scoliosis

The forward bending test according to Adams and rib hump quantification by scoliometer are common clinical examination techniques in idiopathic scoliosis, although precise data about the change of axial surface rotation in forward bending posture are not available. In a pilot study the influence of leg length inequalities on the back shape of five normal subjects was clarified. Then 91 patients with idiopathic scoliosis with Cobb-angles between 20° and 82° were examined by rasterstereography, a 3D back surface analysis system. The axial back surface rotation in standing posture was compared with that in forward bending posture and additionally with a scoliometer measurement in forward bending posture. The changes of back shape in forward bending posture were correlated with the Cobb-angle, the level of the apex of the scoliotic primary curve and the age of the patient. Averaged over all patients, the back surface rotation amplitude increased from 23.1° in standing to 26.3° in forward bending posture. The standard deviation of this difference was high (6.1°). The correlation of back surface rotation amplitude in standing with that in forward bending posture was poor (R2=0.41) as was the correlation of back surface rotation in standing posture with the scoliometer in forward bending posture measured rotation (R2=0.35). No significant correlation could be found between the change of back shape in forward bending and the degree of deformity (R2=0.07), likewise no correlation with the height of the apex of the scoliosis (R2=0.005) and the age of the patient (R2=0.001). Before forward bending test leg length inequalities have to be compensated accurately. Compared to the standing posture, forward bending changes back surface rotation. However, this change varies greatly between patients, and is independent of the type and degree of scoliosis. Furthermore remarkable differences were found between scoliometer measurement of the rib hump and rasterstereographic measurement of the vertebral rotation. Therefore the forward bending test and the identification of idiopathic scoliosis rotation by scoliometer can be markedly different compared to rasterstereographic surface measurement in the standing posture.

Acquired spondylolysis after implantation of a lumbar ProDisc II prosthesis: case report and review of the literature.

Study Design. A case of acquired lumbar spondylolysis following lumbar disc arthroplasty L5–S1 in an 40-year-old woman and review of the literature. Objectives. To present and discuss a case of acquired lumbar spondylolysis after implantation of an artificial disc L5–S1 that may have impaired a good clinical result requiring additional posterior lumbar instrumentation and fusion in order to improve understanding of this condition and to propose an effective method of surgical management. Summary of Background Data. Lumbar disc arthroplasty is a possible surgical option for patients with degenerative disc disease. Acquired spondylolysis is a rare but known complication of spinal fusion but has never been described as a consequence of mobile disc arthroplasty. The authors present the first case in the literature who developed this complication. Methods. A 40-year-old woman with severe osteochondrosis L5–S1 and discogenic lumbar back pain underwent implantation of an artifical disc. Surgery and postoperative course were uneventful and the patient improved significantly as for back pain and mobility. Eighteen months after surgery, the patient was again admitted to our outpatient clinic for back pain that had slowly increased over time. Results. The radiologic workup showed a new spondylolysis L5 without a spondylolisthesis. Because of unsuccessful conservative treatment, the patient underwent posterior lumbar instrumentation and fusion L5–S1, leading to a significant pain reduction and a good clinical outcome. Conclusion. Spine surgeons should be aware of the possibility of lumbar disc arthroplasty to induce acquired spondylolysis impairing good clinical results.

Post-discectomy syndrome treated with lumbar interbody fusion

We studied 27 patients with post-discectomy syndrome. All patients had Lumbar Interbody Fusion with titanium cages and pedicle screw fixation either as Anterior (ALIF, n=18) or as Transforaminal Lumbar Interbody Fusion (TLIF, n=9). Follow-up ranged from 24 to 94 months. The clinical and radiological data were compared. The outcome was evaluated using the Oswestry low back pain disability score and the visual analogue pain intensity scale. Outcomes were similar for all patients regardless of surgical technique and showed a significant improvement at final follow-up.ResuméNous avons étudié 27 malades présentant un syndrome post-discectomie. Dix-huit malades ont été traités par une fusion vertébrale lombaire antérieure et neuf par une fusion transforaminale avec fixation par vis pédiculaire. Le suivi était de 24 à 94 mois. Les données clinique et radiologiques ont été comparées et le résultat évalué en utilisant les Scores d’Oswestry et l’échelle visuelle analogique pour la douleur. Le résultat était semblable pour tous les malades sans influence de la technique chirurgicale et a montré une amélioration significative au suivi final.

Transient hemiplegia in posterior instrumentation of scoliosis.

Study Design. A case of transient hemiplegia during posterior correction and instrumentation of scoliosis in an 18-year-old woman. Objective. To present a case of transient hemiplegia most probably resulting from an arteriovenous fistula. Summary of Background Data. Neurologic impairment in spinal surgery is a feared complication. Common reasons are direct or indirect trauma to neural elements, intraoperative hypotension, ischemia, bleeding, metabolic dysbalances, or drug effects. Review of the literature did not reveal any case of transient hemiplegia similar to the presented one in which none of the mentioned pathologies could be found. Case Summary. An 18-year-old woman with a right long thoracic lordoscoliosis measuring 67° Cobb angle and a marfanoid phenotype underwent posterior correction and transpedicular instrumentation from T3 to L2. After uneventful correction of the deformity through rod rotation, the wake-up test revealed a right-sided hemiplegia without facial asymmetry or other neurologic abnormalities affecting structures above the spinal cord. The rods were removed, the pedicle screws left in place, and the patient was turned on her back. Within 30 minutes after extubation, the neurologic deficits disappeared completely. Extensive diagnostic workup, including magnetic resonance angiography, did not show any pathologic findings explaining the transient hemiplegia. Two weeks later, the surgical correction was completed. After rod rotation again, right-sided hemiplegia was found in the wake-up test. Leaving the correction and after finalizing surgery, the patient was turned on her back and a 5 × 3-cm mass became apparent in her right sternocleidomastoid region. Color-coded duplex sonography revealed an arteriovenous fistula between the right external carotid artery and the right internal jugular vein. After extubation, the mass disappeared and within minutes all neurologic functions returned to normal again. Conclusions. Spine surgeons should be aware of arteriovenous malformations as a potential cause of neurologic disturbances.