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Objective: Balanced frontal curve correction with horizontal shoulder levels, restoration of sagittal plane and vertebral derotation with a fusion length as short as possible., Indications: Curves larger than 40-50° Cobb angle; furthermore age, location, degree of rotation, and sagittal plane deviation have to be considered., Surgical Technique: Posteriorly, segmental pedicle screw instrumentation with a high screw density (80%) and both titanium alloy and cobalt chrome rods. Freehand screw placement under consideration of both natural and deformity-induced pedicle morphology. Correction via reduction screws or instruments. Combined correction technique with rod rotation, segmental screw approximation to the generally concave rod and segmental correction of vertebral translation. Moderate concave distraction and convex compression. If needed, final in situ bending of the rods. Schwab type I osteotomies; in rigid curves type II osteotomies. Fusion with local bone, allogenic bone and/or bone substitutes (i.e., tricalcium phosphate). Intraoperative placement of a thoracic epidural catheter for postoperative pain control. Neurological monitoring throughout the procedure., Postoperative Management: Mobilization on postoperative day 1 with focus on pain management and nutrition. Return to school after 4 weeks. Physiotherapy after 3 months, cycling after 3-6 months, and full sport activities after 1 year., Results: Frontal curve correction of 60-80%, sufficient sagittal plane correction. Correction of rib hump 40%. Patient satisfaction is high at 95% and long-term revision rates of < 10%., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Purpose: Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure for degenerative disk disease. While numerous studies have analyzed complication rates and risk factors this study investigates the extent to which complications after TLIF spondylodesis alter the clinical outcome regarding pain and physical function., Methods: A prospective clinical two-center study was conducted, including 157 patients undergoing TLIF spondylodesis with 12-month follow-up (FU). Our study classified complications into three subgroups: none (I), minor (IIa), and major complications (IIb). Complications were considered "major" if revision surgery was required or new permanent physical impairment ensued. Clinical outcome was assessed using visual analog scales for back (VAS-B) and leg pain (VAS-L), and Oswestry Disability Index (ODI)., Results: Thirty-nine of 157 patients (24.8%) had at least one complication during follow-up. At FU, significant improvement was seen for group I (n = 118) in VAS-B (-50%), VAS-L (-54%), and ODI (-48%) and for group IIa (n = 27) in VAS-B (-40%), VAS-L (-64%), and ODI (-47%). In group IIb (n = 12), VAS-B (-22%, P = 0.089) and ODI (-33%, P = 0.056) improved not significantly, while VAS-L dropped significantly less (-32%, P = 0.013) compared to both other groups., Conclusion: Our results suggest that major complications with need of revision surgery after TLIF spondylodesis lead to a significantly worse clinical outcome (VAS-B, VAS-L, and ODI) compared to no or minor complications. It is therefore vitally important to raise the surgeon´s awareness of consequences of major complications, and the topic should be given high priority in clinical work.

Background: Thoracic epidural anesthesia (TEA) is one of the pillars of perioperative pain care. Particularly for spine surgery which causes significant postoperative pain TEA seems like an appealing option. However, beneficial effects of a TEA are questionable when the catheter is not used intraoperatively, a decision that is usually based on the surgeon's wish to perform immediate neurological examination postoperatively., Methods: Forty patients undergoing transforaminal lumbar interbody fusion surgery (TLIF) were randomized into two groups. Patients received preoperative insertion of a TEA. For patients in the intraoperative group an epidural infusion was started preoperatively and maintained throughout. For patients in the postoperative group the epidural infusion was started once neurological examination had been performed. The primary outcome measure in this study was postoperative requirements of piritramide during the first two postoperative hours. Secondary outcomes involved postoperative pain numeric rating scale (NRS) scores, intraoperative opioid requirements, side effects and ability to perform direct postoperative neurological examination., Results: Postoperative group patients required significantly more opioids both intra- and postoperatively (P=0.036 and P=0.039) and NRS scores were significantly higher on admission to recovery, at 30 and 60 min as compared to patients in the intraoperative group (P=0.013; P=0.004 and P=0.012). Early postoperative neurological examination was feasible in all patients in both groups., Conclusions: Epidural catheters used intraoperatively during TLIF are feasible, significantly reduce pain, intra- and postoperative use of opioids and do not influence the quality of neurological tests directly after the surgical procedure.

Introduction: A balanced ratio of the main parameters of lumbar lordosis (LL) and pelvic incidence (PI) has high clinical relevance. A postoperative mismatch of LL and PI has been described in the literature to be associated with an inferior clinical outcome and higher postoperative revision rates. The aim of this retrospective, radiological study is to evaluate the magnitude of relordosing in mono-/bisegmental TLIF spondylodesis affecting the spino-pelvic alignment and the main contributing factors., Materials and Methods: 164 patients (pat.) underwent monosegmental (n = 115, G1) and bisegmental (n = 49, G2) TLIF spondylodesis, respectively, for different indications in 2016 in our hospital. Pelvic incidence, lumbar lordosis (preop., postop., 3 months postop.), implanted cage sizes, and the use of additional Smith-Petersen osteotomies were analysed retrospectively. Patients were divided into three groups depending on match of LL/PI (PI-LL < 10° green, PI-LL = 10-20° yellow, PI-LL > 20° red). Furthermore, a differentiation was made between surgeons with more than or less than 10 years of spinal surgery experience, respectively., Results: 29.6% of pat. in G1 and 16.3% in G2 showed a highly pronounced preoperative spino-pelvic mismatch (red). A high grade of mismatch (yellow) between LL/PI was seen in 29.6% in G1 and in 38.8% in G2. The remaining patients already had a balanced ratio of LL/PI (green). Through relordosing TLIF the LL could be corrected significantly (p < 0.05). Therefore, the number of patients with a balanced sagittal alignment (green) increased from 40.9% preop. to 70.4% postoperative in G1 and from 44.9 to 85.7% in G2 (p < 0.05). The number of pat. with highly pronounced preoperative mismatch (red) could be lowered in G1 from 29.6 to 13.9% and in G2 from 16.3 to 2% postoperative (p < 0.05). In G1, the preoperative LL could be corrected from 46.3° to 53.8° (yellow) and 35.7° to 45.8° (red), while in G2, a correction was possible from 43.4° to 51.5° (yellow) and 36.6° to 50.1° (red) (p < 0.05). No significant difference of segmental/complete LL was found between radiologic measurement immediately postoperative and at the 3-month follow-up. In monosegmental fusion higher cages sizes lead to a better match of LL/PI (p < 0.05). The specific cage lordosis (5° vs. 10°) had no influence on the extent of relordosing. Experienced surgeons had significant higher postoperative matches of LL/PI (p < 0.05) and accomplished more osteotomies (p < 0.05)., Discussion: This retrospective study demonstrates that significant relordosing and, therefore, correction of the spino-pelvic alignment are possible with mono-/bisegmental TLIF spondylodesis. Positive influence of higher cage sizes and surgeon's experience was shown. We conclude that the ratio of LL/PI should be taken into account preoperatively in lumbar fusion surgery when planning mono-/bisegmental TLIF spondylodesis to optimize spino-pelvic alignment. These slides can be retrieved under Electronic Supplementary Material.

Background: For patients with adolescent idiopathic scoliosis, shoulder balance influences their treatment satisfaction and psychological well-being. Several parameters are known to affect postoperative shoulder balance, but few prognostic models are as yet available., Purpose: This study aimed to identify independent predictive factors that can be used to assess preoperatively which patients are at risk of postoperative shoulder elevation, and to build a linear prediction model., Methods: N = 102 patients with all Lenke types were reviewed radiographically before surgery and 1 year afterward. The outcome measures were coracoid height difference (CHD), clavicular angle (CA), and clavicle-first rib intersection difference (CiRID). Predictive factors commonly used in the literature were investigated using correlation analysis and statistical testing. Significant contributing factors were included in three multiple linear regression models (for CHD, CA, and CiRID)., Results: The mean shoulder level (CHD) significantly changed from a lower left shoulder value of -8.5 mm before surgery to 3.3 mm at the follow-up examination. A high preoperative left shoulder level by CiRID, a large amount of Cobb angle correction of the distal thoracic curve, a low preoperative Cobb angle in the lumbar curve, and a structural proximal thoracic curve proved to be determinants and thus risk factors for left-sided shoulder elevation after surgery. The three models predicting CHD, CA, and CiRID at the follow-up examination included these four risk factors and were significant., Conclusions: Preoperative variables have the strongest influence on shoulder level after spinal instrumentation. Additionally, extensive correction of the distal thoracic curve can cause elevation of the left shoulder.

Cement augmentation of pedicle screws biomechanically increases screw purchase in the bone. However, clinical complications may occur. The pros and cons of the technique are discussed from different clinical perspectives.

Introduction: There is a lack of data in the literature on surgical correction of severe neuromuscular scoliosis in patients with serious extent of cerebral palsy. The purpose of this retrospective cohort study was to analyze the radiological and clinical results after posterior-only instrumentation (group P) and combined anterior-posterior instrumentation (group AP) in severe scoliosis in patients with Gross Motor Function Classification System grades IV and V., Materials and Methods: All eligible patients who underwent surgery in one institution between 1997 and 2012 were analyzed, and charts, surgical reports, and radiographs were evaluated with a minimum follow-up period of 2 years., Results: Fifty-seven patients were included (35 in group P, 22 in group AP), with a median follow-up period of 4.1 years. The preoperative mean Cobb angles were 84° (34 % flexibility) in group P and 109° (27 % flexibility) in group AP. In group P, the Cobb angle was 39° (54 % correction) at discharge and 43° at the final follow-up, while in group AP the figures were 54° (50 % correction) at discharge and 56° at the final follow-up. Major complications occurred in 23 vs. 46 % of the patients, respectively. Preoperative curve flexibility was an important predictor for relative curve correction, independently of the type of surgery., Conclusion: Posterior-only surgery appears to lead to comparable radiological results, with shorter operating times and shorter intensive-care unit and hospital stays than combined surgery. The duration of surgery was a relevant predictor for complications.

Background: Posterior pedicle screw instrumented correction and fusion have become the gold standard in the surgical treatment of thoracic scoliosis. However, in thoracic Lenke type C curves selective posterior fusion of the thoracic curve may lead to spinal imbalance. The aim of the study was to analyse the radiological results of selective anterior thoracic fusion using a standard open dual rod technique with special respect to spontaneous lumbar curve correction (SLCC)., Methods: Twenty-eight patients (26 patients with Lenke 1C and 2 patients with Lenke 2C curves) with an average age of 15 years were surgically treated with an anterior dual rod system through a standard open double thoracotomy approach. Average clinical and radiological follow-up was 4 years (24-84 months)., Results: Fusion was carried out mostly from end-to-end vertebra. The primary curve was corrected from 61.6° (average correction on reverse bending films 42.9 %) to 27.1° (56.0 % correction) with an average loss of correction of 2.2°. The secondary lumbar curve measured 47.7° preoperatively (40-56°, average correction on reverse bending films 66.2 %) and corrected spontaneously to 30.1° (36 % SLCC) and remained stable without any cases of deterioration or decompensation during follow-up. Lumbar apical vertebral translation increased minimally by an average of 4 mm directly, postoperatively, and returned to an average of preoperative values during follow-up. All but two curves remained as type C lumbar modifier at follow-up. Preoperatively, three patients showed a marked coronal imbalance of more than 3 cm (all left, average 4.0 cm); at follow-up, two patients were still out of balance by more than 3 cm (all to the left, average 3.4 cm). Preoperatively, a marked shoulder imbalance of more than 1.0 cm was found in 11 patients; this was corrected in all patients to <1.0 cm at follow-up. The apical vertebral rotation measured according to Perdriolle was corrected from 23.5° to 15.0° in the thoracic spine (36.2 % correction) with an average clinical reduction of the rib hump of 63.2 %. In the lumbar spine, there was no relevant radiological derotation; however, clinically, the lumbar hump corrected spontaneously by 44.3 %. Thoracic kyphosis measured 28.5° preoperatively and 32.3° at follow-up. All six patients with a preoperative hypokyphosis (<20°) of an average of 9.5° were successfully corrected to an average thoracic kyphosis of 23.8° at follow-up. There were no cases of junctional thoracolumbar kyphosis. There were neither reoperations nor implant failures with pseudarthrosis., Conclusion: Selective anterior correction and fusion in primary thoracic curves with lumbar modifier type Lenke C resulted in a reliable and satisfactory SLCC. Advantages of anterior versus posterior techniques are the true segmental derotation with excellent rib hump correction and a superior restoration of thoracic kyphosis.

During anterior scoliosis instrumentation with a dual-rod system, the vertebrae are dissected anterolaterally. After surgery, some patients report a change in temperature perception and perspiration in the lower extremities. Sympathetic lesions might be an explanation for this. The aim of this clinical study was to investigate sympathetic function after anterior scoliosis instrumentation. A total of 24 female patients with idiopathic scoliosis (mean age at follow-up, 23.8 years) who had undergone anterior instrumentation on average 6.6 years earlier were included. Due to the suspected relevance of the sympathetic L2 ganglion, two groups were created: a T12 group, in which instrumentation down to T12 was carried out (n = 12), and an L3 group, in which instrumentation down to L3 was done (n = 12). Sympathetic function was assessed by measuring skin temperature at the back of the foot, a plantar ninhydrin sweat test and sympathetic skin responses (SSRs) following electrical stimulation. The side on which the surgical approach was carried out was compared with the contralateral, control side. Health-related quality of life was investigated using the Scoliosis Research Society SRS-22 patient questionnaire. In the T12 group, mean temperatures of 29.6 degrees C on the side of the approach versus 29.5 degrees C on the control side were measured (P > 0.05); in the L3 group, the mean temperatures were 33.2 degrees C on the approach side versus 30.5 degrees C on the control side (P = 0.001). A significant difference between the T12 group and the L3 group (P < 0.001) was observed on the approach side, but not on the control side (P = 0.15). The ninhydrin sweat test showed reduced perspiration in 11 of 12 patients in the L3 group on the approach side in comparison with the control side (P = 0.002). In the T12 group, no significant differences were noted between the left and right feet. SSRs differed significantly between the two groups (P = 0.005). They were detected in all nine analyzable patients in the T12 group on both sides. In the L3 group, they were found on the approach side only in 4 of 11 analyzable patients versus 11 patients on the control side. The results of the SRS-22 questionnaire did not show any significant differences between the two groups. In conclusion, anterior scoliosis instrumentation with a dual-rod system including vertebrae down to L3 regularly leads to lesions in the sympathetic trunk. These are detectable with an increase in temperature, reduced perspiration and reduced SSRs. The caudal level of instrumentation (T12 vs. L3) has an impact on the extent of impairment, supporting the suspected importance of the L2 ganglion. The clinical outcome does not seem to be significantly limited by sympathetic trunk lesions.

Indications for surgical treatment of idiopathic scoliosis are progressive curves greater than 40-50 degrees. In most cases, fusion of only the primary (structural) curve(s) is sufficient due to the flexibility and spontaneous correction of the secondary curves. Therefore, it is crucial to identify both primary and secondary curves. According to the Lenke classification, all curves with a residual curve of more than 25 degrees on the bending films and those with a pathological kyphosis are regarded as structural and should be fused, whereas the nonstructural curves can be left unfused. However, according to reports in the literature and to the author's experience, clinical parameters such as shoulder level and rib or lumbar hump as well as radiometric criteria such as rotation are relevant as well. In summary, the Lenke classification is an important and helpful tool for analysing idiopathic curves and determining fusion length, even though each scoliosis case needs to be evaluated individually, especially taking clinical parameters into account.

In spinal fusion procedures, the local bone that is resected serves as the base bone graft for attaining biological fusion. The local bone is frequently not sufficient and requires supplementary grafting. Autologous bone transplantation is still regarded as the gold standard but might cause additional complications; also, autograft resources are limited. Alternatively, allografts and a wide variety of different bone substitutes are available.The bone substitutes currently used in scoliosis surgery are presented, and their clinical significance is elucidated by a review of the literature. Furthermore, our own experiences and clinical practice are compared with those in the literature and are critically discussed. The recently growing number of scientific publications reporting on bone substitutes reflects the immense interest and relevance of this issue. In scoliosis surgery, calcium phosphate ceramics together with bone marrow aspirate are increasingly applied.Although harvesting of autologous bone continues to be the accepted standard to extend the local autograft in scoliosis surgery, there is a clear trend toward the use of bone substitutes.

The objective of this study is to compare the clinical and radiographic results of ultraporous beta-tricalcium phosphate (beta-TCP) versus autogenous iliac crest bone graft (ICBG), through prospective randomized pilot study (EBM-Level 1), as graft extenders in scoliosis surgery. In the posterior correction of scoliosis, local bone resected as part of the procedure is used as the base bone graft material. Supplemental grafting from the iliac crest is considered the gold-standard in posterior spinal fusion. However, autograft is not available in unlimited quantities, and bone harvesting is a source of significant morbidity. Ultraporous beta-TCP might be a substitute for ICBG in these patients and thus eliminate donor site morbidity. A total of 40 patients with adolescent idiopathic scoliosis (AIS) were randomized into two treatment groups and underwent corrective posterior instrumentation. In 20 patients, ICBG harvesting was performed whereas the other half received beta-TCP (VITOSS) to augment the local bone graft. If thoracoplasty was performed, the resected rib bone was added in both groups. Patients were observed clinically and radiographically for a minimum of 20 months postoperatively, with a mean follow-up of 4 years. Overall pain and pain specific to the back and donor site were assessed using a visual analog scale (VAS). As a result, both groups were comparable with respect to the age at the time of surgery, gender ratio, preoperative deformity, and hence length of instrumentation. There was no significant difference in blood loss and operative time. In nine patients of the beta-TCP group and eight patients of the ICBG group, thoracoplasty was performed resulting in a rib graft of on average 7.9 g in both groups. Average curve correction was 61.7% in the beta-TCP group and 61.2% in the ICBG group at hospital discharge (P=0.313) and 57.2 and 54.3%, respectively, at follow-up (P=0.109). Loss of curve correction amounted on average 2.6 degrees in the beta-TCP group and 4.2 degrees in the comparison group (P=0.033). In the ICBG group, four patients still reported donor site pain of on average 2/10 on the VAS at last follow-up. One patient in the beta-TCP group was diagnosed with a pseudarthrosis at the caudal end of the instrumentation. Revision surgery demonstrated solid bone formation directly above the pseudarthrosis with no histological evidence of beta-TCP in the biopsy taken. In conclusion, the use of beta-TCP instead of ICBG as extenders of local bone graft yielded equivalent results in the posterior correction of AIS. The promising early results of this pilot study support that beta-TCP appears to be an effective bone substitute in scoliosis surgery avoiding harvesting of pelvic bone and the associated morbidity.

Adjacent segment degeneration (ASD) is discussed to impair long-term outcome after lumbar interbody fusion. Nevertheless the amount and origin of degeneration and its clinical relevance remain unclear. Only little data is published studying quantitative disc height reduction (DHR) as indicator for ASD in long-term follow-up. Forty patients (23 men, 17 women) (group 1: degenerative disc disease, n = 27; group 2: lytic spondylolisthesis, n = 13) underwent lumbar 360 degrees instrumentation and fusion between 1991 and 1997. Preoperative and follow-up lateral lumbar radiographs were studied. Disc heights of first and second cephalad adjacent segments were measured by Farfan's technique and Hurxthal's technique modified by Pope. Clinical outcome was studied using Oswestry disability index (ODI) and visual analogue scale (VAS). Age, gender, prior surgery, fusion rate and number of fusion levels were investigated as potential factors affecting the outcome. Mean follow-up was 114 (72-161) months. Clinical outcome showed an improvement of 44.6% in ODI and 43.8% in VAS with a tendency towards better results in group 2. Fusion rate was 95%. Disc height of the first cephalad adjacent segment in all patients was reduced by on average 21% (Farfan, P < 0.001) and 19% (Pope, P < 0.001), respectively, and that of the second adjacent level by on average 16% (Farfan, P < 0.001) and 14% (Pope, P < 0.001), respectively. A tendency towards more disc height reduction (DHR) in the degenerative group was observed. Advanced age correlated with advanced DHR (P < or = 0.003, r = 0.5). Multiple level fusion led to a more pronounced DHR than 1-level fusion (P = 0.028). There was a tendency towards more DHR in the first adjacent disc compared to the second. Gender, prior surgery of the fused segment and fusion level did not affect the amount of DHR. There was no correlation between the clinical outcome and DHR. Lumbar fusion is associated with DHR of adjacent discs. This may be induced by additional biomechanical stress, ongoing degeneration affecting the lumbar spine and advancing age. However, clinical outcome is not correlated with adjacent DHR.

Introduction: In scoliosis patients treated with long segment spinal fusion, degenerative changes like retrolisthesis and disc space narrowing below fusion have been observed. However, there is disagreement concerning their incidence and dependency on the location of the lowest instrumented vertebra., Materials and Methods: To evaluate temporal changes in disc height and posteroanterior displacement (indicating listhesis) below fusion, 40 patients with adolescent idiopathic scoliosis, mainly treated with Cotrel-Dubousset instrumentation, were retrospectively investigated in this longitudinal study with a follow-up of on average 9.2 years (median 9.4 y) after surgery. Disc height and displacement were measured from lateral radiographs by means of distortion-compensated roentgen analysis (DCRA). Additionally, a mathematical model was developed to determine the influence of vertebral tilt in scoliosis on disc height and displacement., Results: Overall, no significant decrease in disc height was observed during follow-up. Concerning listhesis a small but significant retrolisthesis was found in segments L2/L3 and L3/L4. Compared with normative data, there was no significant listhesis for the L5/S1 segment. Nevertheless, separating the study group into subsamples of identical distal fusion level revealed a significant correlation between the amount of posteroanterior displacement at L5/S1 and the location of the lowest instrumented vertebra. With a reduction of free motion segments, listhesis increased into posterior direction. Taking the tilt correction into account led to considerably increased values of disc height whereas displacement was affected only to a minor degree., Conclusions: Long segment spinal fusion in young patients with idiopathic scoliosis did not lead to disc space narrowing during 9.2 years follow-up. However, the observed increase in retrolisthesis potentially indicates the initiation of a degenerative process. These only minimal changes might be referred to the preservation of a physiologic lumbar lordosis. Without correction for vertebral tilt disc space narrowing is overestimated.

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.

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.

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 degrees to 10.9 degrees) in the digital radiometric rotation analysis, surface derotation amounted to 49% (range from 9.6 degrees to 4.9 degrees) in the rasterstereography, and to 70% in the clinical scoliometer measurement (range from 8.0 degrees to 2.4 degrees ). In group 2, there was an increase of rotation of the noninstrumented secondary thoracic curves by 30% (range from 5.0 degrees to 6.5 degrees ) in digital radiometry, by 32.9% in the rasterstereography (range from 8.5 degrees to 11.3 degrees), and a 28.3% increase in scoliometer measurement (range from 6.0 degrees to 7.7 degrees)., 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.

The unilateral transforaminal approach for lumbar interbody fusion as an alternative to the anterior (ALIF) and traditional posterior lumbar interbody fusion (PLIF) combined with pedicle screw instrumentation is gaining in popularity. At present, a prospective study using a standardized tool for outcome measurement after the transforaminal lumber interbody fusion (TLIF) with a follow-up of at least 3 years is not available in the current literature, although there have been reports on specific complications and cost efficiency. Therefore, a study of TLIF was undertaken. Fifty-two consecutive patients with a minimum follow-up of 3 years were included, with the mean follow-up being 46 months (36--64). The indications were 22 isthmic spondylolistheses and 30 degenerative disorders of the lumbar spine. Thirty-nine cases were one-level, 11 cases were two-level, and two cases were three-level fusions. The pain and disability status was prospectively evaluated by the Oswestry disability index (ODI) and a visual analog scale (VAS). The status of bony fusion was evaluated by an independent radiologist using anterior-posterior and lateral radiographs. The operation time averaged 173 min for one-level and 238 min for multiple-level fusions. Average blood loss was 485 ml for one-level and 560 ml for multiple-level fusions. There were four serious complications registered: a deep infection, a persistent radiculopathy, a symptomatic contralateral disc herniation and a pseudarthrosis with loosening of the implants. Overall, the pain relief in the VAS and the reduction of the ODI was significant (P<0.05) at follow-up. The fusion rate was 89%. At the latest follow-up, significant differences of the ODI were neither found between isthmic spondylolistheses and degenerative diseases, nor between one- and multiple-level fusions. In conclusion, the TLIF technique has comparable results to other interbody fusions, such as the PLIF and ALIF techniques. The potential advantages of the TLIF technique include avoidance of the anterior approach and reduction of the approach related posterior trauma to the spinal canal.

Aim: The aim of this study was to evaluate the clinical and radiological results of surgical treatment of thoracic and lumbar vertebral osteomyelitis by means of one-stage extrafocal posterior stabilisation, anterior debridement, and anterior column reconstruction., Method: A retrospective analysis of the peri- and postoperative parameters of 62 patients with a clinical and radiographic follow-up of 2.6 years that were available for 46 patients was performed. In 42 cases, the anterior column was restored with structural bone grafts, in 20 patients, expandable titanium cages filled with morsellised autologous bone and antibiotic collagen sponges were used. To assess the course of spinal alignment a radiometric analysis was undertaken. Furthermore, the Roland-Morris score (RMS) was applied to evaluate the back pain-related disability., Results: The diagnosis was made no earlier than 2.7 months after the first symptoms. Preoperatively, 40 % of the patients presented with neurological impairment, of these 76 % improved after surgery. Staphylococcus aureus was the most common pathogen isolated (32 %), Mycobacterium tuberculosis was found in 11 % of the patients. Except for one patient with revision for persistent infection and consecutive failure of the bone graft, primary eradication of the infection was achieved in all cases. At follow-up, bony fusion was radiographically observed in all patients. When using cages, the segmental loss of correction was significantly lower than when using bone grafts (1.0 vs. 4.1 degrees ). At follow-up the RMS averaged 6.6., Conclusion: One-stage extrafocal posterior stabilisation combined with anterior debridement and anterior column reconstruction with bone grafts or titanium cages is a safe and effective strategy for patients with vertebral osteomyelitis in need of surgery. Titanium cages have proven to be biomechanically advantageous, especially in cases of extensive destruction and are not associated with higher rates of persistence or recurrence of infection compared to autologous bone grafts.

Between 1991 and 1998, we treated 72 patients with fusion of the lumbar spine using posterior pedicle screw fixation followed by anterior retroperitoneal insertion of a titanium cage filled with autogenous bone graft. All patients had chronic low back pain after failed conservative treatment. We were able to review 54 patients with a mean follow-up of 51 (24-97) months. The mean Oswestry low back pain disability score improved from 56.8 preoperative to postoperative 29.8 and 31.2 at follow-up (p<0.05). The mean visual analog pain intensity scale improved from 8.3 to 4.0 postoperative and 4.8 at follow-up (p<0.05). The results demonstrate that circumferential lumbar fusion can be an option for the treatment of chronic low back pain.

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 degrees 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 x 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.

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.

The role of spinal implants in the presence of infection is critically discussed. In this study 20 patients with destructive vertebral osteomyelitis were surgically treated with one-stage posterior instrumentation and fusion and anterior debridement, decompression and anterior column reconstruction using an expandable titanium cage filled with morsellised autologous bone graft. The patients' records and radiographs were retrospectively analysed and follow-up clinical and radiographic data obtained. At a mean follow-up of 23 months (range 12-56 months) all cages were radiographically fused and all infections eradicated. There were no cases of cage dislocation, migration or subsidence. Local kyphosis was corrected from 9.2 degrees (range -20 degrees to 64 degrees ) by 9.4 degrees to -0.2 degrees (range -32 degrees to 40 degrees ) postoperatively and lost 0.9 degrees during follow-up. All five patients with preoperative neurological deficits improved to Frankel score D or E. Patient-perceived disability caused by back pain averaged 7.9 (range 0-22) in the Roland-Morris score at follow-up. In cases of vertebral osteomyelitis with severe anterior column destruction the use of titanium cages in combination with posterior instrumentation is effective and safe and offers a good alternative to structural bone grafts. Further follow-up is necessary to confirm these early results.

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 degrees to 92 degrees 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 degrees to 2 degrees after surgery and to 8 degrees 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.

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.

Objective: To determine the accuracy of rasterstereographic three-dimensional back surface analysis and reconstruction of the spine in cases of severe idiopathic scoliosis treated by anterior correction and fusion., Design: Comparison of digitized radiographic curves and rasterstereographic curves by best fit superimposition and calculation of root mean square differences as parameters of similarity., Background: Rasterstereography has been proven to be accurate in scoliosis up to 50 degrees Cobb angle. Since 1989 the device is in clinical routine use for non-operatively treated patients and reduces the need for otherwise indispensable radiographs significantly., Methods: Fifty two patients with severe idiopathic scoliosis with Cobb angles up to 88 degrees were examined rasterstereographically and radiographically. Forty eight pre-operative anterior-posterior radiographs and 101 post-operative anterior-posterior radiographs were digitized. Radiographic and rasterstereographic curves were compared and the root mean square differences were calculated as parameters of precision of rasterstereographic reconstruction., Results: Accuracy of rasterstereography in idiopathic scoliosis with Cobb angles between 50 degrees and 88 degrees is satisfactory. The root mean square difference of the radiographic and rasterstereographic curves was 6.4 mm for lateral deviation and 4.5 degrees for vertebral rotation. After anterior scoliosis surgery the precision of the device is good. The root mean square difference for lateral deviation was 3.4 mm and 3.2 degrees for rotation. Considering both groups an average root mean square of 4.7 mm and 3.7 degrees was calculated., Conclusions: Accuracy in severe scoliosis up to 88 degrees Cobb angle was satisfactory. The results of this first evaluation of surgically treated severe scoliosis showed a good accuracy after anterior surgery. The system can be used for post-operative follow up examinations and may reduce the number of X-rays considerably. In contrast to radiography, CT or MRI rasterstereography provides an objective quantification and documentation of the post-operative cosmetic improvement of the back shape in standing posture. RELEVANCE STATEMENT: Based on the findings of this study rasterstereography in future enables both objective quantification of cosmetic improvement and significant reduction of X-rays in idiopathic scoliosis with Cobb angles higher than 50 degrees before and after anterior surgical correction and fusion.

Aim: The expert evidence of operated patients with idiopathic scoliosis is determined by functional and pulmonary restriction. The degree of deformity and the extent of fusion is crucial for grading disability. In a retrospective study on the quality of life (SF-36) and low back pain (Roland-Morris Score) of 82 patients (22 - 40 years) with idiopathic scoliosis treated with Harrington instrumentation the grading was registered., Method: An average of 16.7 years after the surgery, these data were correlated with the type and size of curve and to the extension of fusion., Results: Compared to the age-matched healthy population, there was no significant difference in the physical SF-36 scale (P = 0.98). Surgically treated patients showed significantly lower scores than at baseline in the psychological SF-36 scale (P = 0.005). Sixty-five (79.3 %) of the eighty-two patients reported no or occasional back pain in the Roland Index. Five patients (6.1 %) complained of chronic back pain. 33 patients (40 %) were legally defined in their rate of disability as severely handicapped patients. The grading disability was associated with the physical SF-36 scale (P < 0.001) and the low back pain (P = 0.02). A significant correlation between the grading disability and the extent of fusion (P = 0.53) or the size of curve (p = 0.4) could not be proven., Conclusion: Despite good long-term outcomes, 40 % of operated treated patients with idiopathic scoliosis were legally defined as severely handicapped persons. The additional measurements of quality of life and low-back pain can improve legal assessment in orthopaedics.

Aim: The posterior extension osteotomy leads to a lengthening of the anterior column, which is associated with neurological complications and the risk of injuring retroperitoneal structures. Especially in high-grade syndesmophytosis the results are dissatisfactory. In this study we report on the results of an alternative procedure named the transpedicular subtraction osteotomy., Method: After resection of the posterior elements of the vertebra at the level of the osteotomy, a wedge of the vertebral body including the pedicles with posterior basis is resected followed by an instrumented closing wedge, which leads to relordosation. 12 patients were treated with this method and reexamined with a minimum follow-up of 2 years (2 - 6 years). The level of osteotomy ranged from T12 to L3., Results: The mean segmental correction averaged 30.1 degrees (25 - 36 degrees ). The overall relordosation averaged 35.9 degrees and was related to additional correction in the adjacent segments. With this dissatisfactory a sufficient correction of spinal balance and visual axis was obtained. All patients were satisfied with the result of the operation and would undergo surgery again from a retrospective point of view., Conclusion: With the transpedicular subtraction osteotomy fixed kyphotic deformities of the spine in patients with ankylosing spondylitis can be corrected produce safely. The level of osteotomy is discussed and should depend upon the apex of kyphosis.

Rasterstereography enables to reduce the number of radiographs in the conservative treatment of idiopathic scoliosis (Cobb angles below 50 degrees). The aim of the present study was to evaluate the use of rasterstereography in severe scoliosis before and after anterior surgery. The results show that the accuracy (as compared to radiographs) is lower in the pre-operative rasterstereographs. However, after operation the Cobb angles were less than 50 degrees in all cases and the accuracy of the rasterstereographs was similar to that of non-operated scolioses. This finding might allow a significant reduction of post-operative radiographs.

Aim: Radiographic analysis of long-term results following CDI., Methods: Retrospective analysis of radiographs of 43 patients with idiopathic right thoracic scoliosis with an average follow-up of 82 months. Extensive radiographic analysis with special regard to curve correction in the frontal and sagittal planes., Results: The average Cobb-angle of the preoperative primary curve was 61.6 degrees (min.: 40 degrees, max.: 84 degrees ), the correction postoperatively was 51.1 % representing 29.9 degrees. Due to the loss of correction of 7.1 degrees, the overall outcome was 39.9 % by the time of follow-up. More than 90 % of the loss of correction occurred within the first 2 years. The lumbar secondary curve correction was 47.2 % (preop.: 37.5 degrees; postop.: 19.8 degrees ). Average fusion length was 11 segments, fusion usually ended two vertebrae below the end vertebra. Translation of the apex was corrected by 38.8 % (preop.: 4.9 cm; postop.: 3.0 cm), tilt of the last instrumented vertebra by 44.2 % (preop.: 18.2 degrees; postop.: 10.16 degrees ). The amount of derotation was negligible (preop.: 24.1 degrees; postop.: 22.6 degrees ). The readjustment of a preoperative pathologic sagittal profile, meaning a thoracic hypokyphosis, was successful in 12 out of 15 cases. Blood loss, duration of operation and complications were documented., Conclusion: CD-Instrumentation in scoliosis surgery offers a long-lasting suffcient correction of the fronal and a good correction of the sagittal plane. Stability of correction is achieved 2 years after operation.

We report on a case of occlusion of the left common iliac artery due to arteriosclerosis and consecutive thrombotic occlusion of the left popliteal artery in a 52-year-old man following anterior retroperitoneal interbody fusion of L4--S1. Initial symptoms included leg pain and numbness of the lateral shank, which were thought to be a result of lumbar nerve root irritation from surgery. Diagnosis was not made until 13 days after surgery, when motor deficits were observed. Angiography showed occlusion of the left common iliac artery and thromboembolism of the left popliteal artery. After thromboendarterectomy of the common iliac artery and thrombectomy of the popliteal artery, motor deficits of the left foot were resolved whereas symptoms of pain and sensory deficits continued. Spine surgeons should be aware of this rare complication in cases of postoperative leg pain or of neurologic deficits in the lower extremity after anterior lumbar interbody fusions.

Question: In order to evaluate the outcome of the operative treatment of neuromuscular scoliosis 45 patients were studied prospectively., Methods: 27 Patients were operated by posterior correction and fusion using the Münster Posterior Doublerod-System (MPDS) (GI). 18 Patients were treated with one-stage ventro-dorsal procedure in combination of VDS with MPDS (GII). For all patients, medical and radiographic records were available, with a minimum follow-up of 2 years. Postoperative management, bloodloss and complications will be discussed., Results: In group I the main curve (76.3 degrees), by an average flexibility of 36.1%, were corrected by 53.5% and 52.3% at follow up. The mean pelvic obliquity (7.7 degrees) averaged 53.8%. The mean major scoliosis of group II (107.1 degrees), by an average flexibility of 25%, gets improved by 61%. At most recent follow-up, the mean correction was 61.5%. The mean pelvic obliquity (23.1 degrees) averaged 73.2% and 70.6% respectively. The mean bloodloss in group I was 1840 ml and in group II 2180 ml., Conclusion: The data in the current study support the benefit of the operative treatment of patients with severe neuromuscular scoliosis. The quality of life gets improved by stability in seating and standing by correction of pelvic obliquity and trunk instability.

Introduction: So far only radiometric and clinical methods have been available for the evaluation of results after anterior scoliosis surgery. Rasterstereography has proved to be a reliable method for three-dimensional surface measurement of conservatively treated idiopathic scoliosis patients. Therefore, patients treated operatively with anterior instrumentation were examined using rasterstereography to determine the three-dimensional correction of the spinal deformity. The aim was to measure back shape deformity, in particular derotation, and thus cosmetic improvements., Methods: 31 patients with idiopathic thoracic, thoracolumbar and lumbar scoliosis (Cobb angle 57.2 degrees) were examined with raster stereography preoperatively, postoperatively and after follow-up (25.2 months) in a standardized standing posture. Standing radiographs were compared with raster stereography., Results: The mean Cobb angle was reduced from 57.2 degrees to 17.2 degrees, the rasterstereographic maximal surface rotation from 16.5 degrees to 10.8 degrees, and the vertebral rotation according to Perdriolle from 29.2 degrees to 16.7 degrees. During follow-up the Cobb angle increased to 20.8 degrees, and surface rotation to 11.3 degrees. Vertebral rotation remained constant. Lordosis and kyphosis angles changed only slightly., Conclusion: Rasterstereography is a suitable tool for analyzing the three-dimensional correction of spinal deformities after anterior scoliosis surgery. In particular, the cosmetic improvement is clearly demonstrated. The measurement of surface rotation allows objective quantification of the obtained derotation.

Halm-Zielke Instrumentation (HZI) was developed to eliminate the disadvantage of ventral derotation spondylodesis (VDS)-Zielke in terms of lack of primary stability and in order to simplify sagittal plane control. Within a prospective clinical trial started in 1993, we have studied whether HZI fulfills these demands. HZI is an anterior double-rod system with a two screw per vertebral body fixation. The longitudinal components consist of a threaded VDS rod and a solid rod, which are attached to a hinge-conducted lid plate. Twenty-nine consecutive patients with idiopathic scoliosis and curves ranging from 36 degrees to 92 degrees were treated with HZI. The follow-up period ranged from 1 to 4 years. Correction of the frontal plane within the instrumented levels averaged 71.6% and 70.5% postoperatively and at follow-up, respectively. Derotation averaged 53.7% and mean correction of the tilt of the lowest instrumented vertebra was 69.5% at final follow-up. Thoracolumbar kyphosis was present in eight patients and was always completely corrected from +18.8 degrees to 3.3 degrees on average. One implant-related complication involved a screw breakage 18 months postoperatively without adverse effects. There was no case of pseudoarthrosis. All patients were mobilized without any additional external immobilization in terms of a brace or cast, and were allowed to go swimming for physiotherapeutical purposes immediately after wound healing. This study proves that HZI is a primary stable implant to perform VDS. Implant-related disadvantages typical of VDS are eliminated. Thereby, the period of rehabilitation is shortened by many months due to avoidance of cast and brace treatment.

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

Aim of the Study: Halm-Zielke Instrumentation (HZI) was developed to eliminate the disadvantage of VDS-Zielke in terms of lack of primary stability and in order to simplify sagittal plane control. Since 1993 we study within a prospective clinical trial, whether HZI fulfills these demands., Methods: HZI is an anterior double-rod system with a two screw per vertebral body fixation. The longitudinal components consist of a threaded VDS-rod and a solid rod, which are attached to a hinge-conducted lid plate. 25 consecutive patients with idiopathic scoliosis and curves ranging from 36 degrees to 92 degrees were treated with HZI. The follow-up period ranges from 2 to 4 years., Results: Correction of the frontal plane within the instrumented levels averaged 71.4% and 70.4% postoperatively and at follow-up, respectively. Derotation averaged 51.7% and mean correction of the tilt of the lowest instrumented vertebra was 69.5% at final follow-up. Thoracolumbar kyphosis was present in 7 patients and always completely corrected. One implant related complication, a screw breakage 12 months postoperatively without adverse effects was noted. There was no case of pseudarthrosis. All patients were mobilized without any additional external immobilization in terms of a brace or cast and were allowed to go swimming for physio-therapeutical purposes immediately after wound healing., Conclusion: This study proves that HZI is a primary stable implant to perform the Ventral Derotation Spondylodesis. The VDS-typical implant related disadvantages are eliminated. With this the period of rehabilitation is shortened by many months due to avoidance of cast and brace treatment.

Introduction: In order to evaluate the results of posterior correction and fusion using the Münster Posterior Doublerod-System (MPDS) 48 patients with idiopathic scoliosis were studied prospectively., Methods: All patients underwent clinical examination and radiological analysis of the frontal and sagittal plane preoperatively, postoperatively and at follow-up (2-4 years). Pedicle screws were used at the lumbar and thoracolumbar spine exclusively., Results: The preoperative average Cobb angle was 61.4 degrees with an average flexibility of 36.8% to 38.8 degrees. The average postoperative Cobb angle was 24.8 degrees (59.6%) with an average loss of correction of 2.6 degrees Cobb angle (3.6%). Due to the use of thoracolumbar and lumbar pedicle screws instrumented fusion could be stopped at the lower endvertebra in 71%. Patients in whom only pedicle screws had been used improved correction of frontal plane could be shown compared to combined instrumentations with hooks and screws., Conclusion: The posterior instrumentation guarantees primary stability with good results of correction and allows brace free treatment postoperatively. The postoperative correction compared to the results at follow-up proves the stability of the instrumentation largely. The results of mainly pedicle screw based instrumentations verify that an improved correction can be achieved. In most cases fusion levels end at the lower end vertebra and therefore are shorter compared to instrumentation's based on hooks only.

While scoliosis and kyphosis are the most common spinal deformities in patients with myelomeningocele, single lordotic deformitics are rare. There are only few reports about the operative treatment of a primary thoracic lordosis of -135 degrees Cobb angle. By means of a dorso-ventral-dorsal procedure correction and stabilisation of the lordotic deformity was performed. A correction of -26 degrees Cobb angle was achieved without loss of correction during follow up of 18 months. The case report shows that in individual cases even severe lordotic deformities can be treated with surgery successfully. An anterior-posterior procedure should be considered. The case is discussed with the rare national and international literature.

Aim of the Study: To evaluate the midterm radiographic behaviour of femorocortical allograftrings (FCA) in lumbosacral fusions in patients with disabling low back pain., Methods: The radiographs of 41 patients with a minimum follow-up of 2 years were analysed by an independent orthopedic radiologist. The fusion rate was determined on lateral tomograms routinely obtained at 3 months intervals. On lateral radiographs the posterior intervertebral disc height as well as the segmental lordosis were measured. Changes of the allografting such as mottling, resorption and incorporation were registered., Results: The fusion rate was 95.2%. Time to radiographic fusion averaged 8.7 months (2-34 months) and in 66.1% radiographic fusion occurred without significant subsidence. In 18.6% fusion with subsidence resulted from resorption of the FCA and in 15.3% the FCA had protruded into the vertebral body. The posterior intervertebral disc height increased postoperatively by 1.9 millimeters on average. However, postoperative height loss was the rule and occurred within the first 12 postoperative months, resulting in a negligible final gain in height of 0.3 millimeters on average. The final gain in segmental lordosis was 1.3 degrees on average. Complete graft incorporation occurred in 16 of 62 segments (25.8%)., Conclusion: The described technique has proven to be highly effective in achieving a high fusion rate with a stable midterm graft behaviour.

The radiographic fusion rates, graft behaviour and clinical outcome of 41 patient with simultaneous combined anterior lumbar interbody fusion and posterior arthrodesis with translaminar screws were reviewed independently. In all patients a femoral cortical allograft (FCA) ring filled with autologous iliac crest cancellous bone was used anteriorly to replace the disc and achieve interbody fusion. The follow-up averaged 30.6 months, with a minimum follow-up of 24 months. All patients had disabling low-back pain with different degrees of radiating leg pain and either discogenic pain (n = 24) or a postdiscectomy syndrome (n = 15) respectively postfusion syndrome (n = 2). The overall fusion rate was 95.2% (59 of 62 segments). Time to radiographic fusion averaged 8.7 months (range 2-34 months), and in 66.1% radiographic fusion occurred without significant subsidence. In 18.6% fusion with subsidence resulted from resorption of the FCA and in 15.3% the FCA had protruded into the vertebral body. The posterior intervertebral disc height (PIVDH) increased postoperatively by 2 mm on average. However, loss of PIVDH was the rule, and occurred within the first 12 postoperative months, resulting in a negligible final gain in height of 0.3 mm on average. The segmental lordosis was increased by 3 degrees; however, loss of lordosis during the first 6 postoperative months led to a final gain in lordosis of 1.3 degrees on average. Graft incorporation occurred in 16 of 62 segments (25.8%) and was observed at an average of 21.9 months postoperatively. Subjectively, 82.4% of the patients were satisfied or highly satisfied with the clinical result of the fusion operation. In conclusion, the described technique has proven to be highly effective in achieving a high fusion rate with a good patient outcome.

Objectives: In order to evaluate the benefits of the doublerod-VDS in the operative treatment of scoliosis the midterm results were critically analysed with specific respect to primary stability., Methods: 24 patients with either idiopathic or neuromuscular curves were treated with the Doublerod-VDS. In some cases a singlerod instrumentation had to be carried out in the cranial fusion area due to too small vertebrae (Hybrid-VDS). Patients with thoracic curves were ambulated without any external support, the thoracolumbar curves were ambulated in a light, semirigid vest for a few months. All data including early and late complications were collected prospectively and a thorough radiometric analysis was carried out., Results: Fusion was mostly carried out from end- to end-vertebra. The correction of the idiopathic curves averaged 60.2% (preoperative Cobb angle 67.3 degrees) with a loss of correction of 5.2 degrees. In the neuromuscular curves the average correction was 61.1% (preoperative Cobb angle 99.8% degrees) and the average loss of correction 4.2 degrees. There was no kyphogenic effect noted. In 6 cases a rod fracture was observed, in 4 cases the fracture occurred within the singlerod instrumentation in hybrid-VDS. Two of these patients developed a pseudarthrosis with loss of correction but without any symptoms., Conclusions: The hybrid-VDS does not offer any advantages compared to the Zielke-VDS. However, the doublerod-VDS in thoracic curves is primary stable and does not require any external support postoperatively. In thoracolumbar curves a light vest is suggested for the first postoperative months during day time.

Introduction and Aim of the Study: Halm-Zielke Instrumentation (HZI), in german speaking countries also named the Münster Anterior Doublerod System, was developed to eliminate the disadvantage of VDS-Zielke in terms of lack of primary stability. Additionally sagittal plane control should be improved. Within a prospective clinical trial it was examined, if HZI fulfilled these demands., Methods: HZI is an anterior doublerod system with a two screw per vertebral body fixation. The longitudinal components consist of a threaded VDS-rod and a solid rod. 12 consecutive patients with idiopathic scoliosis and curves ranging from 36 degrees to 77 degrees were treated with HZI., Results: Correction of the frontal plane averaged 75% and 73.8% postoperatively and at follow-up, respectively. Derotation averaged 49.3%. Thoracolumbar kyphosis was present in four patients and always completely corrected. Implant related complications were not noted. All patients were treated without any additional external immobilisation., Conclusion: The aim of improvement of VDS in terms of primary stability and control or improvement of the sagittal plane was completely achieved.

We report on 48 patients with a mean postoperative follow-up of 7.7 years. 9 patients underwent simple anterior derotation spondylodesis (VDS), 31 patients were additionally fused with posterior Harrington spondylodesis. In 7 of 8 patients the Dwyer compression spondylodesis (DCS) was completed with the Harrington instrumentation. 2 of 3 scoliosis were idiopathic, the residual cases were mainly neuromuscular. The primary curve (preoperative mean: 69.9 degrees) was initially corrected by 62.8% and sustained a loss of correction of 7.6 degrees resp. 10.9% during long-term follow-up. The long-term loss of correction was maximal after DCS showing 10.4 degrees (14.4%), on the average, and minimal after combined VDS and Harrington spondylodesis showing 6.9 degrees (9.3%). After simple VDS the long-term progression of the curve was 7.0 degrees (12.9%). In this group the initial correction was above-average high showing 76.4%. The main loss of correction occurred during the first 2 years after surgery. The long-term correction stability did not show significant differences between simple VDS and combined antero-posterior instrumentation. After anterior instrumentation of the primary curve the secondary cranial nerve spontaneously straightened up by 30%, on the average, and remained stable in the long-term. The anterior instrumentation of the spine lead to a mean loss of lordosis of 13.6 degrees which in the long-term additionally increased by 6.4 degrees due to the anterior epiphyseodesis effect. In 17 patients (42.5%) 24 fractures of the 3 mm-threaded VDS-compression rod occurred. In case of single rod fractures no higher loss of correction or differences in incidence of pain were observed in comparison to intact implants.

Especially in idiopathic thoracolumbar scoliosis the approach and sort of instrumentation have controversially been discussed over the past years. Since 1986 32 patients with adolescent thoracolumbar scoliosis underwent operative treatment, 20 patients were treated with Cotrel-Dubousset Instrumentation (CDI), 10 patients underwent Ventral Derotation Spondylodesis (VDS). In 2 cases a combined two-stage VDS and CDI were performed. The follow-up was 38 months in the CDI-group and 19 months in the VDS-group. Length of the curve and the fusion were identical in the VDS-group. In the CDI-group, however, length of the fusion exceeded curve length by 4 segments on average. With CDI the fusion was carried down to L4 in most cases, in some cases to L5. Curve correction of the primary curve averaged 70% with VDS (preoperative mean 84 degrees) and 64% with CDI (preoperative mean 65 degrees). We observed a spontaneous correction of the secondary curve of 38% after VDS. With CDI the correction of the secondary curve averaged 42%, however, in secondary curves measuring more than 50 degrees primary and secondary curve were fused. A preoperatively physiological sagittal plane in the CDI-group remained unchanged after operative treatment. With VDS an average kyphosis of the thoracolumbar junction of +22 degrees was corrected to +7 degrees. We conclude that in the operative treatment of severe thoracolumbar scoliosis VDS offers significant advantages compared to CDI and should therefore be preferred. In moderate scoliotic deformities, where the number of caudally unfused segments is equal in both systems, CDI is justified.

The advantages of VDS according to Zielke with excellent 3-dimensional correction and shorter fusion levels in comparison to posterior instrumentation techniques are well known. A disadvantage is the necessity of long postoperative immobilization in a body cast or brace due to lack of primary stability. The aim of the VDS double-rod instrumentation is augmentation of the system with the possibility of postoperative treatment without plaster cast or braces. Following thoracolumbophrenotomy and ligation of the segmental vessels double-hole vertebra clamps are inserted. First VDS screws are placed in the posterior holes of these plates. With a 4-mm threaded compression rod correction is obtained by centripetal compressive forces on the nuts. Next VDS screws for the 5-mm threaded rod are inserted into the anterior holes of the vertebral clamps. The rod is implanted in a slightly compressive manner and augments the system. In a prospective study 8 patients, 4 with idiopathic and 4 with neuromuscular scoliotic deformities, underwent this surgical procedure and now have a follow-up of 2 years. Curves ranged from 45 degrees to 131 degrees Cobb angle. All patients were treated without plaster casts or braces postoperatively, but with only a semielastic vest for 4 to 6 months. Unusual intra- and postoperative complications have not been noted. Correction of the primary curve averaged 69.4% at follow-up. Tilt of the caudal end vertebra was corrected 75% to an average of 6.3 degrees. Spontaneous partial correction of the upper secondary curve was noted in all cases. Rod fracture of the 5-mm rod without fracture of the 4-mm rod at this level was seen in 1 patient without loss of correction. Solid fusion was achieved at every level in all patients. The sagittal plane was not adversely affected by the instrumentation. However, larger patient numbers and a longer follow-up are necessary.

Severe fracture-dislocation of the thoracic spine without neurological deficit is rare. Both translational and rotational deformity of the midthoracic spine makes transection of the cord almost inevitable due to the confined dimensions of the cord and spinal canal. Even though associated fractures of posterior elements are frequently seen, they seldom result in neural sparing. The case of a 24-year-old man who sustained a severe rotational fracture-dislocation of T9/T10 with considerable anterolateral displacement is reported. Due to a fractured left pedicle and a right-sided vertical fracture through the posterior aspect of the vertebral body, alignment of the posterior elements in the spinal canal was maintained and there was no neurological deficit. The patient was operatively treated with posterior segmental instrumentation, and was completely asymptomatic at follow-up 5 years later.