Spondylolysis and spondylolisthesis in children and adolescents: II. Surgical management

Surgical management is indicated for children and adolescents with spondylolysis and low-grade spondylolisthesis (< or =50% slip) who fail to respond to nonsurgical measures. In situ posterolateral L5 to S1 fusion is the best option for those with a low-grade slip secondary to L5 pars defects or dysplastic spondylolisthesis at the lumbosacral junction. Pars repair is reserved for patients with symptomatic spondylolysis and low-grade, mobile spondylolisthesis with pars defects cephalad to L5 and for those with multiple-level defects. Screw repair of the pars defect, wiring transverse process to spinous process, and pedicle screw-laminar hook fixation are surgical options. The ideal surgical management of high-grade spondylolisthesis (>50% slip) is controversial. Spinal fusion has been indicated for children and adolescents with high-grade spondylolisthesis regardless of symptoms. In situ L4 to S1 fusion with cast immobilization is safe and effective for alleviating back pain and neurologic symptoms. Instrumented reduction and fusion techniques permit improved correction of sagittal spinal imbalance and more rapid rehabilitation but are associated with a higher risk of iatrogenic nerve root injuries than in situ techniques. Wide decompression of nerve roots combined with instrumented partial reduction may diminish the risk of neurologic complications. Pseudarthrosis and neurologic injury presenting as L5 radiculopathy and sacral root dysfunction are the most common complications associated with surgical management of high-grade spondylolisthesis.     

Reduction of high-grade isthmic and dysplastic spondylolisthesis in 5 adolescents

Treatment of high-grade isthmic and dysplastic spondylolisthesis in children and adolescents remains a challenge. Surgical treatment of spondylolisthesis has been recommended in adolescents with pain refractory to nonoperative modalities, slippage progression, or > 50% slippage on presentation. Controversy exists as to the optimal surgical approach for high-grade spondylolisthesis. In this report, we describe 5 cases of high-grade isthmic and dysplastic spondylolisthesis in adolescents and review the literature on surgical treatment for this entity. Operative records, charts, x-rays, and Scoliosis Research Society outcome questionnaires (SRS-22) were retrospectively evaluated for 5 consecutive patients diagnosed with and treated for high-grade spondylolisthesis. Each patient received treatment consisting of decompression, reduction, and circumferential fusion with transpedicular and segmental fixation from a posterior approach. Two patients had transient L5 nerve root deficit, which resolved within 3 months. Reduction benefits include a decrease in shear stresses (and resulting decreased rates of postoperative pseudarthrosis and slip progression), restoration of sagittal alignment and lumbosacral spine balance, and improvement in clinical deformity.     

One-stage decompression and posterolateral and interbody fusion for severe spondylolisthesis. An analysis of 14 patients

STUDY DESIGN: A retrospective study of 14 patients with high-grade L5-S1 spondylolisthesis surgically treated with one-stage decompression and posterolateral and interbody fusion (technique of Bohlman and Cook). OBJECTIVE: To determine the efficacy of this technique in managing severe lumbosacral spondylolisthesis. SUMMARY OF BACKGROUND DATA: Controversy exists over the most appropriate method for managing high-grade spondylolisthesis. Circumferential in situ fusion from a single-stage posterior approach was described in 1982, but to the current authors' knowledge, there are not many reports on clinical results in the literature. The current authors studied 14 patients (mean age, 21 years) with severe L5-S1 spondylolisthesis. The percentage of slipping averaged 77%; slip angle averaged 36 degrees. The average follow-up period was 30 months. All patients had severe back or radicular symptoms. Two patients had foot drop, and four had minor neurologic dysfunction. Four patients had extremely tight hamstrings. METHODS: Pre- and postoperative radiographic films and computed tomography scans were reviewed. Magnetic resonance imaging was carried out in 11 patients before surgery and at follow-up examination. Patients were evaluated for fusion rate, clinical outcome, and complications. RESULTS: All six patients with motor deficit of the nerve roots showed complete strength recovery at follow-up examination. None of the patients had tightness of hamstrings. Twelve patients demonstrated incorporation of the graft with solid fusion, one patient had a fracture of the fibular graft, and one had graft resorption. All patients but one rated the surgical result as excellent. One patient was not satisfied with the cosmetic result. Transient paresthesias in the leg of the donor graft were documented in two patients. CONCLUSIONS: Posterior decompression of the spinal canal combined with anterior and posterior arthrodesis performed at one stage through a posterior approach is a safe and effective technique for managing severe spondylolisthesis.     

A square to indicate the unstable zone in severe spondylolisthesis

The reduction and stabilisation of high-grade dysplastic developmental spondylolisthesis by means of modern internal fixators can correct slip, but can leave the sagittal alignment unbalanced, causing instability, e.g. in the adjacent, non-fused lumbar segments. Through analysis of the modifications of imbalance in the spine and pelvic ring due to surgical correction, this study defines the unstable zone of high-grade dysplastic developmental spondylolisthesis and proposes a simple radiographic method to identify it.     

Quality of life of patients with high-grade spondylolisthesis: minimum 2-year follow-up after surgical and nonsurgical treatments

Background contextSurgical intervention is generally indicated in a pediatric high-grade spondylolisthesis to prevent the progression of deformity or neurologic deterioration and improve the quality of life. However, the outcome of the treatment on the health-related quality of life (HRQOL) of patients with high-grade spondylolisthesis remains largely unknown.PurposeTo describe the changes in the HRQOL of patients with pediatric high-grade spondylolisthesis after surgical and nonsurgical managements.Study designObservational case series with a minimal of 2-year follow-up.Patient sampleTwenty-eight pediatric patients with high-grade spondylolisthesis from a single institution filled the inclusion criteria. Twenty-three patients were managed surgically and five were managed nonsurgically.Outcome measuresSelf-report measures: Scoliosis Research Society questionnaires (SRS-22). Neurologic examination, radiographic evaluation of slip grade.MethodsThe SRS-22 questionnaire was collected at the baseline (initial presentation for the nonsurgical group and preoperative visit for the surgical group) and at the last follow-up. Differences between baseline and last follow-up were evaluated in both groups. Correlation between the baseline score of SRS-22 score and improvement in the SRS-22 score was determined in surgical patients.ResultsIn surgical patients, total SRS-22 scores were 3.31±0.50 at the baseline and 4.26±0.50 at the last follow-up. In nonsurgical patients, total SRS-22 scores were 4.12±0.16 at the baseline and 4.14±0.38 at the last follow-up. Therefore, variation in the SRS-22 total score was +0.94±0.77 (p<.001) for surgical patients and +0.02 ± 0.35 (p=.854) for nonsurgical patients. Improvement of the SRS-22 score was correlated with a low baseline value of SRS-22 (R²=0.61; p<.001). There was no neurologic or slip deterioration during the follow-up for patients treated nonsurgically.ConclusionsThe HRQOL improves after a surgical intervention for high-grade spondylolisthesis. Patients with lower baseline HRQOL scores are those who benefit the most from surgery. Close observation is a safe and feasible option in selected patients with a good baseline HRQOL and no neurologic impairment.     

Radiographic analysis of spondylolisthesis and sagittal spinopelvic deformity

Traditional radiographic analysis of spondylolisthesis focuses on the regional sagittal deformity at the lumbosacral junction. Pelvic morphology has also been cited as an important factor that contributes to the development of high-grade spondylolisthesis. However, the importance of global sagittal balance of the spine and pelvis in patients with spondylolisthesis has been emphasized recently. Patients with this condition can develop abnormal sagittal spinopelvic balance; restoration of sagittal spinal alignment can improve their health-related quality of life. Reduction has been used to restore alignment, but its role in the management of high-grade spondylolisthesis is controversial. None of the current classification systems take sagittal sacropelvic and spinopelvic balance into account. Improved understanding of the relationship between the spine and pelvis has led to the development of a new classification system that incorporates analysis of spinopelvic balance in the radiographic assessment. This new system may aid surgeons in identifying patients who would benefit from a partial reduction procedure.     

椎弓根钉系统结合椎间融合治疗严重腰椎滑脱

目的评价椎弓根钉内固定系统结合椎间融合治疗严重腰椎滑脱的临床效果。方法2002—2007年应用后路椎弓根钉内固定系统结合椎间融合器治疗32例重度（Meyerding分级Ⅲ和Ⅳ度）腰椎滑脱患者,椎间隙Cage植骨。随访时采用Suk标准判断融合情况,并根据神经损害体征、腰部活动功能和对职业的影响等指标进行疗效评价。结果随访6～36个月,平均22．5个月,优良率90．6％,融合率84．4％,平均腰椎滑脱率由术前的57．3％降低到术后的12．2％。术后并发脑脊液漏2例,暂时性单侧根性疼痛2例,足背皮肤麻木伴轻度的踝关节背屈肌力减弱3例,Cage下沉5例,平均下沉1．1mm。结论椎弓根钉内固定系统结合Cage椎间植骨融合器是治疗严重腰椎滑脱的一种比较安全有效的手术选择。     

Clinical outcome of trans-sacral interbody fusion after partial reduction for high-grade l5-s1 spondylolisthesis

STUDY DESIGN: A clinical retrospective study was conducted. OBJECTIVE: To evaluate the clinical and radiographic outcome of reduction followed by trans-sacral interbody fusion for high-grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: In situ posterior interbody fusion with fibula allograft has improved the fusion rates for patients with high-grade spondylolisthesis. The use of this technique in conjunction with partial reduction has not been reported. METHODS: Nine consecutive patients underwent treatment of high-grade (Grade 3 or 4) spondylolisthesis with partial reduction followed by posterior interbody fusion using cortical allograft. The average age at the time of surgery was 27 years (range, 8-51 years), and the average follow-up period was 43 months (range, 24-72 months). Before surgery, eight patients had low back pain, seven patients had radiating leg pain, and five patients had hamstring tightness. The average grade of spondylolisthesis by Meyerding grading was 3.9 (range, 3-5). Charts and radiographs were evaluated, and outcomes were collected by use of the modified SRS outcomes instrument. RESULTS: Radiographic indexes demonstrated significant improvement with partial reduction and fusion. The slip angle, as measured from the inferior endplate of L5, improved from 41.2 degrees (range, 24-82 degrees ) before surgery to 21 degrees (range, 5-40 degrees ) after surgery. All the patients were extremely or somewhat satisfied with surgery. The two patients who underwent this operation without initial instrumentation experienced fractures of their interbody grafts. Both of these patients underwent repair of the pseudarthrosis with placement of trans-sacral pedicle screw instrumentation and subsequent fusion. CONCLUSIONS: Partial reduction followed by posterior interbody fusion is an effective technique for the management of high-grade spondylolisthesis in pediatric and adult patient populations, as assessed by radiographic and clinical criteria. Pedicle screw instrumentation with the sacral screws capturing L5 is recommended when this technique is used for the treatment of high-grade spondylolisthesis. According to the clinical and radiographic results from this study, partial reduction and posterior fibula interbody fusion supplemented with pedicle screw instrumentation is an effective technique for select patients with high-grade spondylolisthesis at L5-S1.     

A proposal for a surgical classification of pediatric lumbosacral spondylolisthesis based on current literature

The classification presented in this paper is the first specifically designed to guide surgical treatment of L5–S1 spondylolisthesis in children and adolescents. It also presents objective criteria to differentiate between low- and high-dysplastic spondylolisthesis and incorporates recent knowledge in the study of sagittal spinopelvic balance. The proposed classification is based on the following: (1) the degree of slip, (2) the degree of dysplasia, and (3) the sagittal spinopelvic balance. To classify a patient, the degree of slip is quantified first to determine if it is low-grade, high-grade, or a spondyloptosis. Then, the degree of dysplasia is evaluated based on seven criteria, in order to separate patients with low- and high-dysplastic spondylolisthesis. Finally, the sagittal spinopelvic balance is assessed from the measurement of the pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT). For low-grade spondylolisthesis, it is classified as low PI/low SS (nutcracker type) or high PI/high SS (shear type). For high-grade spondylolisthesis, it is classified as high SS/low PT (balanced pelvis) or low SS/high PT (retroverted pelvis). Such a comprehensive classification could allow to better evaluate and compare available surgical techniques, and to optimize the treatment of L5–S1 spondylolisthesis. Because the classification was designed so that groups are organized in an ascending order of severity, it becomes easier and more intuitive to develop an associated surgical algorithm because the complexity of the surgery should increase as the severity of the spondylolisthesis increases. A tentative treatment algorithm is proposed but it is not definitive because further studies are required to define the most appropriate treatment for each group.     

Spondylolisthesis in osteogenesis imperfecta due to pedicle elongation: report of two cases.

STUDY DESIGN: Two cases of spondylolisthesis due to severe elongation of pedicles in osteogenesis imperfecta are reported. OBJECTIVE: To describe an unusual type of spondylolisthesis and its successful management. SUMMARY OF BACKGROUND DATA: Spondylolisthesis is known to occur in osteogenesis imperfecta. Reports in the literature are few. Pedicle elongation resulting in spondylolisthesis has only been reported once. There is no report of a successful treatment of this type of spondylolisthesis resulting from pedicle elongation. METHOD: Two adolescent girls suffering from osteogenesis imperfecta presented with lower back pain and thoracic scoliosis. One of them had high-grade spondylolisthesis of L3-L4, L4-L5, and L5-S1, with a thoracic scoliosis. She was treated with anterior interbody fusion L3 to sacrum without instrumentation. Later, progression of her scoliosis required combined anterior and posterior instrumented fusion T1 to L1. The other girl presented with L5 spondylolisthesis and thoracic scoliosis. She has back pain as well as neurologic symptoms in her legs and is waiting for surgery. RESULTS: At the 3-year follow-up the operated patient is symptom-free from her spine and there has been no progression of either deformity. CONCLUSION: High-grade spondylolisthesis due to elongation of pedicle in osteogenesis imperfecta is uncommon. Anterior interbody fusion of all the involved motion segments has produced good pain relief and arrested deformity progression at the 3-year follow-up.     

Management of spondylolysis and spondylolisthesis in the pediatric population: A review

Typically considered a pediatric disease entity, the treatment of spondylolysis and spondylolisthesis in children and adolescent patients is different from that of adults due to the pathogenesis, skeletal size and immaturity, and mobility of the adjacent spinal segments. This article discusses the classification, natural history, presentation and physical exam findings, and imaging characteristics, as well as nonsurgical and common surgical treatments for low- and high-grade spondylolisthesis, in children and adolescents.     

峡部裂性腰椎滑脱症的手术治疗进展

峡部裂性腰椎滑脱症是一种常见的脊柱退行性疾病,严重影响人们的生活质量。目前腰椎滑脱的手术治疗指征已基本形成共识,针对该病的手术方案主要是峡部修补、椎管减压、滑脱复位、脊柱融合,治疗原则主要是缓解神经压迫、恢复脊柱稳定,但对于各环节实施的具体方式及程度仍存在较大争议。开放手术能够对严重峡部裂腰椎滑脱进行彻底的减压、复位、融合,重建脊柱的稳定性,但手术创伤过大,而微创手术则可以减少对椎旁软组织的损伤,同时减少术中失血量,缩短术后住院及康复时间,降低术中、术后相关并发症的发生率,因而近年来也受到了越来越多临床医生的推崇,但对于重度峡部裂腰椎滑脱的治疗效果欠佳。现就近年来腰椎滑脱的手术治疗进展做一综述。     

腰5椎体Ⅱ度以上峡部裂性滑脱的手术策略

目的探讨腰5椎体Ⅱ度以上峡部裂性滑脱的手术治疗策略。方法 2003年8月～2008年10月,应用经椎间孔腰椎间融合（transforaminal lumbar interbody fusion,TLIF）技术,以小关节突为中心椎管减压、椎间隙松解撑开复位、椎弓根钉棒系统补充复位固定、椎间隙打压植骨联合椎间融合器技术治疗腰5椎体Ⅱ度以上峡部裂性滑脱26例。结果经18～36个月（平均30个月）随访,滑脱椎体复位无丢失,椎间隙高度维持良好,下腰椎生理弧度恢复正常,椎弓根螺钉无断裂、松动,融合器无移位、沉降。25例获骨性融合。根据NaKai评分标准,优良率为84.6%。结论采用TLIF技术治疗腰5椎体Ⅱ度以上滑脱,神经根管减压是影响疗效的关键因素,滑脱椎体复位有利于神经根减压以及椎间融合率的提高,椎体间融合是维持长期疗效的基础。     

Spontaneously stabilized severe dysplastic spondylolisthesis without operation: long-term follow-up of a preteenage patient

Surgical management is the accepted treatment choice for grade III or IV spondylolisthesis, and many satisfactory clinical and radiologic follow-up results have been reported. Very little, however, has been written about long-term results in preteenage patients in whom dysplastic spondylolisthesis has been treated nonoperatively, especially in those who have > or =50% displacement of the fifth lumbar vertebra on the sacrum. We report an unusual case of spontaneous stabilization of severe dysplastic spondylolisthesis in an 8-year-old girl who presented with grade III spondylolisthesis of L5-S1 and was followed up for >14 years in the absence of surgical intervention. On presentation, she complained of a restriction in forward bending and tightness of hamstrings, but she was undisturbed in her daily activities. Initial radiographs showed severe dysplastic spondylolisthesis; however, magnetic resonance imaging (MRI) performed at age 9 years showed that the amount of listhesis was much less than that seen in the initial radiograph. Routine radiographic follow-ups were chosen over early operative measures until she became a teenager. There was no change in the slip, and unusually a gradual ossification of the cartilaginous promontory of the S1 and the posterior lip of the L5 was observed. At 22 years old, the patient is asymptomatic and not conscious of her cosmetic appearance. Surgical treatment has generally been indicated for patients with grade III or IV spondylolisthesis, because slippage progression has been noted in most reported cases. However, MRI may be a tool for predicting which dysplastic spondylolisthesis cases are more likely to progress and therefore circumvent surgical intervention, while maintaining an excellent outcome.     

Intra and inter-observer reliability of determining degree of pelvic incidence in high-grade spondylolisthesis using a computer assisted method

Pelvic incidence was described as a fundamental parameter to describe spino–pelvic balance. In high-grade spondylolisthesis, severe dystrophic changes of the upper sacral endplate may be responsible for technical difficulties in pelvic incidence measurement. We propose to evaluate the reliability of PI measurement in high-grade spondylolisthesis patients and to compare the manual method with a computer-assisted method. In 30 high-grade spondylolisthesis patients, pelvic incidence was measured by manual and computer-assisted technique by the Spineview® software package. We statistically assessed agreement between the manual and the computer-assisted technique, the intra-observer and the inter-observer reliability of the computer-assisted technique. Significant correlation was found (Spearman’s rank R = 0.921 with P<0.001) between manual and computer-assisted results. The paired t test (t = 0.979 with P<0.001) and the intraclass correlation coefficient (ICC) were also significant. Intra- and inter-observer reliability of the computer-assisted technique were excellent with Spearman’s rank correlation from 0.964 to 0.985 with P<0.001, a paired t test from 0.978 to 0.983 with P<0.001) and an ICC from 0.986 to 0.992. Intra- and inter-observer repeatability were better with the computer-assisted method than with the manual technique. We proved the reliability and repetability of a computer-assisted angular measurement method in high-grade spondylolisthesis patients. This validated measurement technique could be now used to measure the main parameters of the sagittal balance of the spine in further studies on spondylolisthesis patients.     

Anterior column support in surgery for high-grade, isthmic spondylolisthesis.

The literature is confusing as to the need for anterior column fusion in the surgical treatment of patients with high-grade dysplastic spondylolisthesis. The current authors present an analysis of consecutive pediatric patients treated surgically for high-grade spondylolisthesis with and without anterior column structural support with emphasis on fusion rates, segmental kyphosis correction, and functional outcomes. Thirty-seven surgical procedures were done in 31 patients for Meyerding Grade 3 or Grade 4 isthmic dysplastic spondylolisthesis. Patients were separated into two groups based on whether they had structural anterior column support (tricortical autogenous iliac crest) in addition to posterior fusion surgery. Group 1 consisted of 18 patients treated only with posterior surgery without anterior structural support (11 patients were treated with L4-sacrum posterior in situ fusion and seven patients were treated with posterior instrumented reduction with decompression and posterior fusion), and Group 2 consisted of 19 patients who had a reduction and circumferential fusion including anterior structural support. All patients had new radiographs taken at the time of followup (average, 3.1 years, range, 2 years-10 years 1 month) and completed a functional outcome questionnaire. The incidence of pseudarthrosis was 39% (seven of 18 patients) in Group 1 and 0% (0 of 19) in Group 2. All seven patients who had pseudarthrosis achieved solid fusion with a second procedure involving circumferential fusion with anterior column structural grafting. Outcomes regarding pain after treatment, function, and satisfaction were high in those patients who achieved solid fusion regardless of surgical procedure.     

Transsacral screw fixation for high-grade spondylolisthesis

Background contextSymptomatic high-grade spondylolisthesis (Meyerding III–V) is usually treated by surgery. Recent literature shows that in situ fusion is better than reduction of the slip and fusion in high-grade spondylolisthesis. Furthermore, the outcome is improved if circumferential fusion is performed in severe spondylolisthesis. We have performed a new technique of circumferential fusion in high-grade spondylolisthesis using two transsacral hollow modular anchorage (HMA) screws supplemented with pedicle screw fixation and posterolateral fusion.PurposeThe aim of the study is to analyze the results of circumferential fusion using transsacral HMA screws supplemented with posterolateral fusion and pedicle screw fixation.Study designRetrospective study.Patient sampleTwelve patients with high-grade spondylolisthesis were reviewed.Outcome measuresOutcome was measured using short form 36 (SF-36) and the ability to return to work at the most recent follow-up.MethodsAll patients had interbody fusion using transsacral HMA screws filled with cancellous bone graft and supplemented with pedicle screw instrumentation and posterolateral fusion.ResultsThe male to female ratio was 2:1 with a mean age of 31 years (range 13–54 years). Eleven of 12 patients had disappearance of leg pain. There were no neurological complications in any of them. Circumferential fusion was achieved in all of them at a mean follow-up of 21 months. The average physical function score improved from 22.50±10.34 to 57.50±17.39 (p=.001, 95% confidence interval [CI] ?44.48 to ?25.52), whereas the average pain score improved from 22.22±13.40 to 61.11±15.35 (p=.001, 95% CI ?51.12 to ?26.66).ConclusionsHMA screws avoid the complications associated with autologous cortical fibular strut graft and also are useful to promote interbody fusion, as the hollowness in the screw can be filled with cancellous bone graft that helps in better fusion. Supplementary pedicle screw fixation is necessary to protect the HMA screws, and they together give a stable construct that can achieve a circumferential fusion in high-grade spondylolisthesis.     

Global sagittal alignment and health-related quality of life in lumbosacral spondylolisthesis

Purpose

Global sagittal alignment is considered as an important aspect in the management of spinal disorders, but the evidence establishing its clinical impact in lumbosacral spondylolisthesis is still poor. This study evaluated the impact of global sagittal alignment on the health-related quality of life (HRQOL) of patients with spondylolisthesis.

Methods

A retrospective study of 149 consecutive unoperated children and adolescents presenting with lumbosacral spondylolisthesis (117 low-grade and 32 high-grade) was performed. Two global sagittal alignment parameters were measured on standing lateral radiographs: spinal tilt (ST) and C7 plumbline deviation (C7P deviation). All patients completed the SRS-22 questionnaire to assess HRQOL. Pearson’s correlations were calculated between parameters of global sagittal alignment and HRQOL. Multiple regression analyses were also undertaken to account for slip percentage and lumbosacral kyphosis (LSK).

Results

Both global sagittal alignment parameters were correlated with the SRS-22 total score. When analyzed separately, the correlation was absent in patients with a low-grade slip but remained significant for patients with a high-grade slip (r = 0.35 for ST; r = ?0.35 for C7P deviation). The relation was strengthened in high-grade spondylolisthesis when considering only patients with a C7P in front of the posterior corner of upper sacral endplate (r = 0.48 for ST; r = –0.48 for C7P deviation) and was also positive for the SRS-22 pain and appearance domains. For these last patients, the relationship with global sagittal alignment remained significant in the multiple regression analysis. HRQOL was particularly worse for high-grade patients with a C7P in front of the hip axis.

Conclusions

In high-grade spondylolisthesis, an increasing positive sagittal alignment was related to a poorer SRS-22 total score, especially when the C7P is in front of the hip axis. Global sagittal alignment should particularly be assessed in patients with high-grade spondylolisthesis.     

High-grade dysplastic spondylolisthesis and spondyloptosis: report of three cases with surgical treatment and review of the literature

High-grade dysplastic spondylolisthesis is extremely rare and always involves the L5-S1 level. It is attributed to congenital dysplasia of the superior articular process of the sacrum. It can remain asymptomatic for a long time and can progress to a more severe grade of olisthesis and spondyloptosis. Surgical treatment has varied from posterior-only in situ fusion to anterior and posterior fusion with complete reduction. Three cases of symptomatic high-grade (4th and 5th grade) dysplastic spondylolisthesis treated surgically with reduction and fusion are presented. Interbody fusion at the level of olisthesis is crucial.     

短节段椎弓根螺钉后路椎间植骨治疗重症峡部裂型腰椎滑脱症

[目的]探讨应用短节段椎弓根螺钉系统内固定并后路椎间植骨融合治疗重症峡部裂型腰椎滑脱症的疗效和手术技巧.[方法]2005年1月～2007年1月,对51例重症峡部裂型腰椎滑脱患者行短节段椎弓根螺钉后路椎间植骨融合术,年龄25～67岁,平均41岁;术前滑脱程度按Meyerding分级标准均大于33%,平均为42%,均有不同程度的神经根受损症状.通过术前、术后脊柱正、侧位X线片和Beaujon functional score(BFS)评分,分析临床疗效,评价治疗效果.[结果]51例患者均获随访,随访时间为2～3年10个月,平均2年8个月.术后平均滑脱复位率92%;椎间隙高度由术前平均4.9 mm恢复至术后的10.3 mm;植骨融合率100%,平均融合时间4个月;BFS评分由术前平均8.1分升至术后2年的17.9分,疗效优良率为91%.随访期间滑脱复位率、椎间隙高度无明显丢失.[结论]短节段椎弓根螺钉系统内固定后路椎间植骨融合术可以用于治疗重症峡部裂型腰椎滑脱症,能保留更多的腰椎运动单元.