Repair of spondylolysis using compression with a modular link and screws

Using the pedicle screw-U rod system for the treatment of double-level lumbar spondylolysis and isthmic spondylolisthesis

Objective

The aim of this study was to evaluate the efficacy of the pedicle screw-U rod system in treating double-level lumbar spondylolysis with or without spondylolisthesis.

Methods

A retrospective study was conducted. Twenty-six patients were included in this study and followed up at 3, 6, and 12 months. Patients without spondylolisthesis were treated with double U-shaped rods (group I), and patients with spondylolisthesis were treated with a lengthened U-shaped rod (group II). Japanese Orthopedic Association (JOA) scores, Oswestry disability index (ODI) scores, disc range of motion (ROM), intervertebral space height of fixed levels and adjacent levels, and grading the degeneration of adjacent segmental intervertebral discs were evaluated preoperatively and postoperatively.

Results

JOA and ODI scores improved significantly at 3 months both in groups I and II. The average bone grafting healing time was 6.1 ± 3.1 months for group I and 6 ± 2.8 months for group II. The intervertebral space heights of L4/L5 and L5/S1 were improved significantly at the final follow-up (p < 0.05 for both groups). Surgical segmental and adjacent segmental ROM had no significant change at the final follow-up, in comparison with data preoperatively (p > 0.05). No significant changes of intervertebral space height (L3/L4) and grading of intervertebral disc degeneration were noted before and after surgery (p = 0.141 and 0.484, respectively).

Conclusions

The pedicle screw-U rod system provided advantages of being easy in repairing symptomatic double-level lumbar spondylolysis. This technique improved disabilities of patients, preserved the lumbar spine ROM, and delayed the degeneration of adjacent segments.

Spondylolysis

Spondylolysis is a bony defect of the pars interarticularis and most often results from repetitive stress. Although spondylolysis is usually asymptomatic, symptomatic spondylolysis is the most common cause of identifiable back pain in children and adolescent athletes. A thorough history and physical exam, as well as appropriate imaging studies are helpful in diagnosis. General first-ine therapy for spondylolysis is conservative and consists of rest from sports, core strengthening, as well as spinal bracing. Patients who have failed conservative therapy may consider surgical repair. This article aims to review the epidemiology, pathophysiology, presentation, and treatment options of spondylolysis.

Comparison of two internal fixation systems in lumbar spondylolysis by finite element methods

BACKGROUND AND PURPOSE

Internal fixation surgeries are currently the most effective treatments for lumbar spondylolysis, but the optimal fixation method is still on debate. This study was designed to compare the biomechanical characteristics of two fixation methods for lumbar spondylolysis, the pedicle screw-U shape rod (PSUSR) internal fixation system, and the pedicle screw-vertebral plate hook (PSVPH) internal fixation system, through three-dimensional finite element analysis, expecting to provide clinical guidance.

METHODS

Four finite element models (A, B, C, D) of L4-S1 vertebral body of a female patient were reconstructed by CT image segmentation. (A: intact model. B: spondylolysis model. C: spondylolysis model with PSUSR internal fixation. D: spondylolysis model with PSVPH internal fixation). Six physiological motion states were simulated by applying 500N concentrated force and 10Nm moment load to four models. The biomechanical advantages of the two internal fixation systems were evaluated by comparing the range of motion (ROM), maximum stress, maximum strain, and maximum displacement of the models.

RESULTS

Compared to model B, the ROM decreased by 35.7%-57.1% in model C and 39.7%-64.8% in model D. The maximum displacements of model C and D both decreased. The maximum stresses in both vertebral and the internal fixation system are greater in model C than those in model D. The maximum stress and strain reduction of L5-S1 intervertebral disc in model D was greater than that in model C. Model D restores the articular cartilage stresses to the normal levels of model A. The maximum stress and maximum displacement of the bone graft in model C are greater than those in model D.

CONCLUSIONS

The PSVPH internal fixation system has better biomechanical properties than PSUSR internal fixation system in several mechanical comparisons. Experimental results suggest that PSVPH internal fixation system can effectively treat lumbar spondylolysis while preserving segmental mobility, and can be the treatment of choice.

Comparing Surgical Treatments for Spondylolysis: Review on Current Research

STUDY DESIGN

Narrative review.

OBJECTIVE

To compare the various surgical methods of repairing spondylolysis defects in regard to improving pain, restoration of function, radiographic improvement, and complication rate.

SUMMARY OF BACKGROUND DATA

Spondylolysis is a defect in the pars interarticularis of the vertebral arch, typically in the lumbar vertebra. Treatment can be nonoperative and/or surgical. There are various types of surgical repair including spinal compression, fusion, and direct pars repair.

METHODS

A comprehensive review of the English literature was performed utilizing Medline, Embase, and Web of Science. Inclusion criteria included papers or abstracts that evaluated the surgical techniques. Exclusion criteria included non-English-language papers or abstracts with inadequate information about outcomes.

RESULTS

Postoperative pain levels and patient function were consistently improved, regardless of surgical technique chosen. Positive clinical outcomes after surgery were seen more often in patients under age 20 and those who underwent minimally invasive repairs. Positive radiographic improvements were reported broadly, although some reported higher rates of nonunion with spinal compression. Complication rates were low throughout and minimally invasive techniques reported decreased blood loss and shorter hospital stays.

CONCLUSIONS

Present surgical options appear largely comparable in terms of their ability to provide meaningful treatment for spondylolysis where conservative treatments have failed or otherwise remain unattempted.

Repair of spondylolysis using a pedicle screw U-shaped rod construct: A preliminary study of 25 young patients with a mean follow-up of 24 months

Study Design:

Prospective case series, therapeutic Level IV.

Objectives:

Functional and radiographic outcome evaluation of patients with spondylolysis treated with pars interarticularis defect repair with iliac bone grafting and application of a construct consisting of a pair of polyaxial pedicle screws connected by a U-shaped rod passing beneath the spinous process.

Methods:

Twenty-five patients (27 operated lumbar levels) with an average of 20 months of follow-up (range 12–24 m) with spondylolysis who met our inclusion criteria were treated with the above-mentioned technique. Functional assessment was by the Visual Analog Score (VAS) for low back pain (LBP) and Oswestry Disability Index (ODI). Fusion was confirmed with plain x-rays and when indicated with computed tomography scan. Return to activities of daily living (ADL) was also assessed.

Results:

There were 16 males (64%) and 9 females (36%), with a mean age of 18 ± 3 years at surgery, with a mean operating time of 79 ± 13 min and a mean blood loss of 186 ± 57 ml. ODI significantly improved from a mean of 63 ± 7 preoperatively to 10 ± 4 at 12 months postoperatively (P < 0.001). The mean preoperative LBP VAS score 8 ± 1 showed also a statistically significant decrease of values to 1 ± 1 at 12 months, (P < 0.001). At 12 m, all patients returned to unrestricted ADL. Pars healing was present in 19 patients (76%) at 6 months and in all patients at 12 months.

Conclusions:

Polyaxial pedicular screws with a U-shaped rod offer an effective and reproducible treatment for spondylolysis with an appropriate fusion rate, predictable return to daily activities, and good pain relief in young adults.

A comparison of the techniques of direct pars interarticularis repairs for spondylolysis and low-grade spondylolisthesis: a meta-analysis

OBJECTIVE Spondylosis with or without spondylolisthesis that does not respond to conservative management has an excellent outcome with direct pars interarticularis repair. Direct repair preserves the segmental spinal motion. A number of operative techniques for direct repair are practiced; however, the procedure of choice is not clearly defined. The present study aims to clarify the advantages and disadvantages of the different operative techniques and their outcomes. METHODS A meta-analysis was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following databases were searched: PubMed, Cochrane Library, Web of Science, and CINAHL ( Cumulative Index to Nursing and Allied Health Literature). Studies of patients with spondylolysis with or without low-grade spondylolisthesis who underwent direct repair were included. The patients were divided into 4 groups based on the operative technique used: the Buck repair group, Scott repair group, Morscher repair group, and pedicle screw-based repair group. The pooled data were analyzed using the DerSimonian and Laird random-effects model. Tests for bias and heterogeneity were performed. The I² statistic was calculated, and the results were analyzed. Statistical analysis was performed using StatsDirect version 2. RESULTS Forty-six studies consisting of 900 patients were included in the study. The majority of the patients were in their 2nd decade of life. The Buck group included 19 studies with 305 patients; the Scott group had 8 studies with 162 patients. The Morscher method included 5 studies with 193 patients, and the pedicle group included 14 studies with 240 patients. The overall pooled fusion, complication, and outcome rates were calculated. The pooled rates for fusion for the Buck, Scott, Morscher, and pedicle screw groups were 83.53%, 81.57%, 77.72%, and 90.21%, respectively. The pooled complication rates for the Buck, Scott, Morscher, and pedicle screw groups were 13.41%, 22.35%, 27.42%, and 12.8%, respectively, and the pooled positive outcome rates for the Buck, Scott, Morscher, and pedicle screw groups were 84.33%, 82.49%, 80.30%, and 80.1%, respectively. The pedicle group had the best fusion rate and lowest complication rate. CONCLUSIONS The pedicle screw-based direct pars repair for spondylolysis and low-grade spondylolisthesis is the best choice of procedure, with the highest fusion and lowest complication rates, followed by the Buck repair. The Morscher and Scott repairs were associated with a high rate of complication and lower rates of fusion.

Posterior Dynamic Stabilization With Direct Pars Repair via Wiltse Approach for the Treatment of Lumbar Spondylolysis: The Application of a Novel Surgery

STUDY DESIGN

A retrospective study to evaluate the clinical outcomes of a novel surgical method for treating patients with lumbar spondylolysis.

OBJECTIVE

The aim of this study was to investigate the effectiveness of posterior ISOBAR TTL stabilization of the lumbar spine with direct pars repair using Wiltse approach for the treatment of lumbar spondylolysis with or without slight spondylolisthesis and discuss the indications of this surgery.

SUMMARY OF BACKGROUND DATA

Surgical treatment of lumbar spondylolysis has yielded relatively good results. However, there are still many limitations of the current surgical methods, including, adjacent level degeneration, restricted indications, and soft tissue damage.

METHODS

Between August 2010 and January 2013, 13 (9 males and 4 females; mean age: 28.2 yrs), patients with lumbar spondylolysis with or without slight spondylolisthesis underwent posterior ISOBAR TTL stabilization of the lumbar spine, with direct pars repair via Wiltse approach. All patients were followed up for at least 24 months at outpatient visits or telephonically. Pre-operative and postoperative radiological assessments included anteroposterior, lateral and flexion extension radiographs, 3-dimensional reconstruction computed tomography (CT), and magnetic resonance imaging (MRI). Data pertaining to intraoperative blood loss, duration of operation, visual analog score (VAS), Oswestry disability index (ODI) scores, and other assessments were collected.

RESULTS

The median follow-up duration was 36 months (range, 24-53 months). Surgery was successful in all patients with no complications; bony fusion of pars was confirmed on CT scan at postoperative 2 years. Significant pain relief was achieved in all patients including those with discogenic pain, those >30 years of age, and those with severe disc degeneration (P < 0.01).

CONCLUSION

We evaluated a new surgical technique for the treatment of patients with spondylolysis with or without slight spondylolisthesis. Besides the good clinical results, the indications for this new surgery are much wider and can potentially overcome the limitations of earlier techniques.

LEVEL OF EVIDENCE

4.

Current Evidence Regarding the Surgical and Nonsurgical Treatment of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee

STUDY DESIGN

Structured literature review.

OBJECTIVES

The Scoliosis Research Society requested an assessment of the current state of peer-reviewed evidence regarding pediatric spondylolysis with the goal of identifying both what is really known and what research remains essential to further understanding.

SUMMARY OF BACKGROUND DATA

Spondylolysis is common among children and adolescents and no formal synthesis of the published literature regarding treatment has been previously performed.

METHODS

A comprehensive literature search was performed. The researchers reviewed abstracts and analyzed by committee data from included studies. From 947 initial citations with abstract, 383 articles underwent full text review. The best available evidence for clinical questions regarding surgical and nonsurgical treatment was provided by 58 included studies. None of the studies were graded as level I or level II evidence. Two of the studies were graded as level III evidence. Fifty-six of the studies were graded as level IV evidence. No level V (expert opinion) studies were included in the final list.

RESULTS

Although natural history studies suggest a benign, relatively asymptomatic course for spondylolysis in most patients, both nonsurgical and surgical treatment series suggest that a substantial number of patients present with pain and activity limitations attributed to spondylolysis. Pain resolution and return to activity are common with both nonsurgical and surgical treatment (80% to 85%, respectively). Although it is implied that most surgically treated patients have failed nonsurgical treatment, the specific treatment modalities and duration required before failure is declared are not well defined. There is insufficient evidence to know which patients will benefit from specific treatment modalities (both nonsurgical and surgical).

CONCLUSIONS

Because of the preponderance of uncontrolled case series and the lack of comparative studies, only low-quality evidence is available to guide the treatment of pediatric spondylolysis.

[Spondylolysis and spondylolisthesis in children and adolescents]

Low back pain is a common cause of lost playing time in young athletes, and spondylolysis is its most common identifiable cause. Despite technological advances in radiology, which can lead to an early diagnosis with better prognosis, progression to spondylolisthesis is sometimes asymptomatic and may not be detected until late stages. There are wide variations, suggesting lack of consensus as regards the objective of treatment, which consists of clinical, radiological, biomechanical or functional improvement. There is also a lack of agreement regarding the ideal conservative treatment, surgical indications and need of slip reduction, and most of the established recommendations are not evidence based. We present a review of literature, which summarizes the current knowledge of spondylolysis and spondylolisthesis in children and adolescents.

A biomechanical research of growth control of spine by shape memory alloy staples

Shape memory alloy (SMA) staples in nickel titanium with shape memory effect are effective for spinal growth control. This study was designed to evaluate the biomechanical properties of the staples and observe the stability of the fixed segments spine after the staples were implanted. According to the vertical distance of the vertebrae, SMA staples of 5, 6.5, and 8 mm were designed. The recovery stress of 24 SMA staples in three groups was measured. The pullout strength of SMA staples and stainless steel staples in each functional spinal unit was measured. Each of the six fresh specimens was divided into three conditions: normal, single staple, and double staples. Under each condition, the angle and torque of spinal movements in six directions were tested. Results show that the differences in recovery stress and maximum pullout strength between groups were statistically significant. In left and right bending, flextion, and extention, the stability of spine was decreased in conditions of single staple and double staples. Biomechanical function of SMA staples was superior to stainless steel staple. SMA staples have the function of hemiepiphyseal compression and kyphosis and scoliosis model of thoracic vertebrae in goat could be successfully created by the fusionless technique.

Lumbar spinal stenosis: who should be fused? An updated review

Lumbar spinal stenosis (LSS) is mostly caused by osteoarthritis (spondylosis). Clinically, the symptoms of patients with LSS can be categorized into two groups; regional (low back pain, stiffness, and so on) or radicular (spinal stenosis mainly presenting as neurogenic claudication). Both of these symptoms usually improve with appropriate conservative treatment, but in refractory cases, surgical intervention is occasionally indicated. In the patients who primarily complain of radiculopathy with an underlying biomechanically stable spine, a decompression surgery alone using a less invasive technique may be sufficient. Preoperatively, with the presence of indicators such as failed back surgery syndrome (revision surgery), degenerative instability, considerable essential deformity, symptomatic spondylolysis, refractory degenerative disc disease, and adjacent segment disease, lumbar fusion is probably recommended. Intraoperatively, in cases with extensive decompression associated with a wide disc space or insufficient bone stock, fusion is preferred. Instrumentation improves the fusion rate, but it is not necessarily associated with improved recovery rate and better functional outcome.

Anatomic parameters: direct intralaminar screw repair of spondylolysis

STUDY DESIGN

Analysis via computed tomography imaging software.

OBJECTIVE

To determine parameters for ideal intralaminar screw trajectory and the feasibility of screw placement at L3, L4, and L5 laminae for pars defect fixation.

SUMMARY OF BACKGROUND DATA

To our knowledge, no studies provide anatomic parameters for ideal intralaminar screw trajectory for treating spondylolysis.

METHODS

We used advanced imaging software for 3-dimensional interactive viewing to analyze 20 randomly selected normal adolescent lumbar computed tomographic scans. The ideal intralaminar screw trajectory was drawn from the inferior lamina, a point chosen to maximize cortical diameter at the isthmus of the lamina and bisect the pedicle. We measured and evaluated ideal trajectory parameters for percutaneous screw placement for pars defect fixation at the L3 to L5 laminae.

RESULTS

The ideal pathway was the thick portion of the lamina between the inferior edge of the lamina and the pedicle. This area was close to the inferior articular process (axial plane), becoming more so at progressively caudal levels. At the ideal trajectory, the mean (standard deviation) coronal angle slightly decreased (L3-L5): 7.3° (5.1°), 6.6° (3.7°), and 4.2° (2.5°), respectively. The trajectory distance increased from cranial to caudal. These parameters increased (L3-L5): mean distance (transverse plane) between the starting point and middle of the spinous process, 1.2 (0.18 cm), 1.3 (0.2 cm), and 1.6 (0.3 cm), respectively; mean screw sagittal angle with respect to the posterior skin, 15.5° (5.0°), 24.3° (6.5°), and 43° (5.8°), respectively; and mean distance for guide wire entry, 28.8 (10.6 cm), 20.1 (5.4 cm), and 11.9 (2.1 cm), respectively.

CONCLUSION

At the ideal screw trajectory, pars fixation by intralaminar screw is uniformly feasible at L3 to L5 laminae, where most patients can accommodate a 4.5-mm screw.

LEVEL OF EVIDENCE

2.

Lumbo-sacral motion conserved after isthmic reconstruction: long-term results

PURPOSE

The purpose of this study was to analyze the clinical and radiological results of repair of the interarticularis pars defect by a modified Buck's repair technique in patients with symptomatic spondylolysis with grade 1 spondylolisthesis. These patients with painful spondylolisthesis are the most eligible for direct repair of the defect rather than lumbo-sacral fusion in an attempt to save motion segments.

METHODS

Forty-six patients with symptomatic spondylolysis with grade 1 spondylolisthesis and normal L4-L5 and L5-S1 disks, following the failure of conservative treatment, underwent surgery between 1988 and 2010. All interventions involved direct pars repair by a modified Buck's repair technique with internal fixation of the defect using screws and cancellous bone grafting. The Oswestry Disability Index (ODI) was used to evaluate the functional outcome. Healing of the pars defect was assessed by plain radiographs and computed tomography (CT) scanning. Motion of the L4-L5 and L5-S1 segments was measured with dynamic radiographs in flexion and extension.

RESULTS

Thirty-five patients were evaluated. The mean follow-up period was 10 years. Functional outcome was excellent in 22 patients (ODI ≤ 10) and good for 8 patients (10 < ODI ≤ 20); five patients continued to have pain (ODI >20). Isthmus bone union occurred in 32 of 35 patients (91.4 %). L4-L5 motion was conserved with a mean angle of 11.8° (0-22); the mean lumbo-sacral angle was 9.9° (0-21).

CONCLUSION

Direct repair of spondylolisthesis was described to avoid fusion in young patients with slight slipping and painful symptoms. A modified Buck's repair technique allows the conservation of L4-L5 motion with a rate of consolidation comparable to other series. The anatomy and stability of the spine were normalized by restoring the continuity of the loose posterior elements using this modified Buck's technique.

Functional outcome following direct repair or intervertebral fusion for adolescent spondylolysis: a systematic review

A systematic review of the literature was performed to establish whether direct repair of the pars defect or intervertebral fusion achieves better Oswestry Disability Index scores in adolescent spondylolysis or low-grade spondylolisthesis. Nine studies fulfilled the inclusion criteria, reporting a minimum total of 80 direct repairs and 108 fusions because of presumed replication of data between studies. Little statistically or clinically significant difference could be established between the two interventions. The only comparative study showed improved long-term outcome with fusion. Further well-designed prospective comparative studies are required to establish the optimum treatment for this condition.

Direct surgical repair of spondylolysis in athletes: indications, techniques, and outcomes

Object

Athletes present with back pain as a common symptom. Various sports involve repetitive hyperextension of the spine along with axial loading and appear to predispose athletes to the spinal pathology spondylolysis. Many athletes with acute back pain require nonsurgical treatment methods; however, persistent recurrent back pain may indicate degenerative disc disease or spondylolysis. Young athletes have a greater incidence of spondylolysis. Surgical solutions are many, and yet there are relatively few data in the literature on both the techniques and outcomes of spondylolytic repair in athletes. In this study, the authors undertook a review of the surgical techniques and outcomes in the treatment of symptomatic spondylolysis in athletes.

Methods

A systematic review of the MEDLINE and PubMed databases was performed using the following key words to identify articles published between 1950 and 2011: “spondylolysis,” “pars fracture,” “repair,” “athlete,” and/or “sport.” Papers on both athletes and nonathletes were included in the review. Articles were read for data on methodology (retrospective vs prospective), type of treatment, number of patients, mean patient age, and mean follow-up.

Results

Eighteen articles were included in the review. Eighty-four athletes and 279 nonathletes with a mean age of 20 and 21 years, respectively, composed the population under review. Most of the fractures occurred at L-5 in both patient groups, specifically 96% and 92%, respectively. The average follow-up period was 26 months for athletes and 86 months for nonathletes. According to the modified Henderson criteria, 84% (71 of 84) of the athletes returned to their sports activities. The time intervals until their return ranged from 5 to 12 months.

Conclusions

For a young athlete with a symptomatic pars defect, any of the described techniques of repair would probably produce acceptable results. An appropriate preoperative workup is important. The ideal candidate is younger than 20 years with minimal or no listhesis and no degenerative changes of the disc. Limited participation in sports can be expected from 5 to 12 months postoperatively.