Reduction and transforaminal lumbar interbody fusion with posterior fixation versus transsacral cage fusion in situ with posterior fixation in the treatment of Grade 2 adult isthmic spondylolisthesis in the lumbosacral spine

Comparative Analysis of Three Posterior-Only Surgical Techniques for Isthmic L5-S1 Spondylolisthesis

OBJECTIVE

To compare adults with isthmic L5-S1 spondylolisthesis who were treated with three different surgical techniques: PS-only, TS, and transforaminal lumbar interbody fusion/posterior lumbar interbody fusion (TLIF/PLIF).

METHODS

This is a retrospective analysis of adults with L5-S1 isthmic spondylolisthesis (grade ≥2) who underwent primary all-posterior operations with pedicle screws. Patients were excluded if they had <1 year follow-up, anterior approaches, and trans-sacral fibular grafts. Patient demographics and surgical, radiographic, and clinical data were compared between groups based on the method of anterior column support: none (PS-only), TS, and TLIF/PLIF.

RESULTS

Sixty patients met inclusion criteria (male patients 21, female patients 39, average age 47 ± 15 years, PS-only 16; TS 20; TLIF/PLIF 24). TS patients more commonly had high-grade slips and markedly greater slip percentage, lumbosacral kyphosis, and pelvic incidence. The three groups were similar for smoking status, visual analog scores/Oswestry Disability Index scores (VAS/ODI), surgical data, and average follow-up (40.1 ± 31.2 months). All groups had similarly notable improvements in Meyerding grade and lumbosacral angle. Slip reduction percentage was similar between groups. While there was a markedly higher overall complication rate for PS-only constructs, all groups had similarly notable improvements in ODI and VAS back scores.

CONCLUSIONS

All-posterior techniques for L5-S1 isthmic spondylolisthesis resulted in excellent improvement in preoperative symptoms and HRQoL scores and similar radiographic alignment. Trans-sacral screws were more commonly used for high-grade slips. The use of anterior column support resulted in fewer overall complications than posterior-only instrumentation.

Does intraoperative reduction result in better outcomes in low-grade lumbar spondylolisthesis after transforaminal lumbar interbody fusion? A systematic review and meta-analysis

Objective

This study aimed to compare the clinical efficacy and safety of reduction vs. arthrodesis in situ with transforaminal lumbar interbody fusion (TLIF) for low-grade lumbar spondylolisthesis.

Study design

Systematic review and meta-analysis.

Methods

A comprehensive literature search was implemented in PubMed, Embase, and Cochrane Library databases. Randomized or non-randomized controlled trials that were published until July 2023 that compared reduction vs. arthrodesis in situ techniques with minimally invasive or open-TLIF for low-grade spondylolisthesis were selected. The quality of the included studies was evaluated by the Newcastle-Ottawa Scale (NOS). Data were extracted according to the predefined outcome measures, including operation time and intraoperative blood loss; short- and long-time follow-up of visual analog scale (VAS) back pain (VAS-BP) and Oswestry Disability Index (ODI); slippage and segmental lordosis; and the complication and fusion rate.

Results

Five studies (n = 495 patients) were finally included. All of them were retrospective cohort studies with Evidence Level II. The pooled data revealed that both techniques had similar patient-reported outcomes (VAS, ODI, and good and excellent rate) during short- and long-term follow-up. In addition, no significant differences were observed in the fusion and complication rates. However, although the reduction group did achieve better slippage correction, it was associated with increased operation time and intraoperative blood loss compared with the in situ arthrodesis group.

Conclusions

Based on the available evidence, intraoperative reduction does not result in better clinical outcomes in low-grade spondylolisthesis after minimally invasive or open-TLIF, and the in situ arthrodesis technique could be an alternative.

Factors Affecting Incomplete L5/S Posterior Lumbar Interbody Fusion, Including Spinopelvic Sagittal Parameters

Study Design

Retrospective observational study.

Purpose

In this study we identify risk factors, including patient demographics, sagittal parameters, and clinical examinations, affecting incomplete L5/S posterior lumbar interbody fusion (PLIF).

Overview of Literature

The lumbosacral spine is considered to have an interbody fusion rate lower than that of the lumbar spine, but few studies have investigated the cause, including investigating the pelvis. We believe that pelvic morphology can affect L5/S interbody fusion of the lumbosacral spine.

Methods

We observed 141 patients (61 men, 80 women; average age, 65.8 years) who had undergone PLIF and checked for the presence of L5/S interbody fusion. We investigated factors such as age, gender, the presence of diffuse idiopathic skeletal hyperostosis (DISH), fusion level, and grade 2 osteotomy, as well as pre-, post-, and post-preoperative L5/S disk height and angle, lumbar lordosis, Visual Analog Scale (VAS) score, Japanese Orthopaedic Association (JOA) score, and pelvic incidence (PI), comparing those with and without L5/S interbody fusion. In addition, we analyzed the patients classified into short-level (n=111) and multi-level fusion groups (n=30).

Results

Overall, the L5/S interbody fusion rate was 70% (short-level, 78%; multi-level, 40%). Age and pre- and post-preoperative L5/S disk angle were significantly different in each fusion level group. DISH presence, grade 2 osteotomy, and postoperative VAS and JOA scores were significantly different in the short-level fusion group, whereas PI was significantly different in the multi-level fusion group.

Conclusions

Incomplete union after L5/S PLIF correlates with advanced age, many fusion levels, and a large value of preoperative and a small value of post-preoperative L5/S disk angles.

Minimally invasive versus traditional open transforaminal lumbar interbody fusion for the treatment of low-grade degenerative spondylolisthesis: a retrospective study

This was a retrospective study. We aimed to compare the clinical efficacy and safety between minimally invasive and traditional open transforaminal lumbar interbody fusion in the treatment of low-grade lumbar degenerative spondylolisthesis (LDS). 81 patients with LDS grades 1 and 2 treated in our spinal department from January 2014 to July 2016 were retrospectively analyzed. The MIS-TLIF group included 23 males and 11 females, while the TO-TLIF group included 29 males and 18 females. Follow-up points were set at 7 days, 3 months, 6 months, 12 months postoperatively and the last follow-up. Various clinical and radiological indicators were used to evaluate and compare the efficacy and safety between the two procedures. 8 cases (3 in the MIS-TLIF group and 5 in the TO-TLIF group) were loss of follow-up after discharge. And the remaining 73 patients were followed up for at least 2 years. No statistically significant difference was observed in the terms of age, sex, BMI, slippage grade, and surgical segments. The MIS-TLIF group had a longer operation and fluoroscopy time compared with the TO-TLIF group. But the MIS-TLIF group was associated with less blood loss, ambulation time, hospital stay, and time of return to work. In each group, significant improvement were observed in BP-VAS, ODI and vertebral slip ratio at any time-point of follow-up when compared with the preoperative condition. When the time-point of follow-up was less than 1 year, the MIS-TLIF group had significant advantages in the BP-VAS and ODI compared with TO-TLIF group. But no significant difference was observed in the BP-VAS and ODI at either 12 month follow-up or the last follow-up. Besides, no statistical difference was detected in vertebral slip ratio at any time-point of follow-up between the two groups. Successful intervertebral bone fusion was found in all patients and no significant difference was found in the incidence of total complications. Thus, we considered that MIS-TLIF and TO-TLIF both achieve satisfactory clinical efficacy in the treatment of low-grade single-segment LDS. But MIS-TLIF appears to be a more efficacious and safe technique with reduced tissue damage, less blood loss and quicker recovery.

Fusion in situ versus reduction for spondylolisthesis treatment: grading the evidence through a meta-analysis

PURPOSE

During surgical procedure on lumbar spondylolisthesis, the role of reducing slip remains controversial. The purpose of the present study was to compare fusion in situ with reduction in clinical and radiographic outcomes.

METHODS

A literature research was performed at PubMed, Embase, Web of Science, and Cochrane Library. After screening by two authors, ten articles were brought into this meta-analysis finally, and the quality was evaluated by the modified Newcastle-Ottawa Scale (NOS). Isthmic, moderate, and serious spondylolisthesis were all analyzed separately. Sensitivity analyses were performed for high-quality studies, and the publication bias was evaluated by the funnel plot.

RESULTS

Most criteria did not have statistical differences between reduction and fusion in situ groups. However, in reduction group, the union rate was significantly higher (P=0.008), the slippage was much improved (P<0.001) and the hospital stay was much shorter comparing to no-reduction group (P<0.001). Subgroup analysis (containing moderate and serious slip, or isthmic spondylolisthesis) and sensitivity analysis were all consistent with original ones, and the funnel plot indicated no obvious publication bias in this meta-analysis.

CONCLUSIONS

Both reduction and fusion in situ for lumbar spondylolisthesis were related with good clinical results. Reduction led to higher rate of fusion, better radiographic slippage, and shorter hospital stay. After sufficient decompression, reduction did not incur additional risk of neurologic impairment compared with fusion in situ.

Biomechanical evaluation of traditional posterior versus anterior spondylolisthesis reduction in a cadaveric grade I slip model

OBJECTIVE

Posterior reduction with pedicle screws is often used for stabilization of unstable spondylolisthesis to directly reduce misalignment or protect against micromotion while fusion of the affected level occurs. Optimal treatment of spondylolisthesis combines consistent reduction with a reduced risk of construct failure. The authors compared the reduction achieved with a novel anterior integrated spacer with a built-in reduction mechanism (ISR) to the reduction achieved with pedicle screws alone, or in combination with an anterior lumbar interbody fusion (ALIF) spacer, in a cadaveric grade I spondylolisthesis model.

METHODS

Grade I slip was modeled in 6 cadaveric L5-S1 segments by creation of a partial nucleotomy and facetectomy and application of dynamic cyclic loading. Following the creation of spondylolisthesis, reduction was performed under increasing axial loads, simulating muscle trunk forces between 50 and 157.5 lbs, in the following order: bilateral pedicle screws (BPS), BPS with an anterior spacer (BPS+S), and ISR. Percent reduction and reduction failure load-the axial load at which successful reduction (≥ 50% correction) was not achieved-were recorded along with the failure mechanism. Corrections were evaluated using lateral fluoroscopic images.

RESULTS

The average loads at which BPS and BPS+S failed were 92.5 ± 6.1 and 94.2 ± 13.9 lbs, respectively. The ISR construct failed at a statistically higher load of 140.0 ± 27.1 lbs. Reduction at the largest axial load (157.5 lbs) by the ISR device was tested in 67% (4 of 6) of the specimens, was successful in 33% (2 of 6), and achieved 68.3 ± 37.4% of the available reduction. For the BPS and BPS+S constructs, the largest axial load was 105.0 lbs, with average reductions of 21.3 ± 0.0% (1 of 6) and 32.4 ± 5.7% (3 of 6) respectively.

CONCLUSIONS

While both posterior and anterior reduction devices maintained reduction under gravimetric loading, the reduction capacity of the novel anterior ISR device was more effective at greater loads than traditional pedicle screw techniques. Full correction was achieved with pedicle screws, with or without ALIF, but under significantly lower axial loads. The anterior ISR may prove useful when higher reduction forces are required; however, additional clinical studies will be needed to evaluate the effectiveness of anterior devices with built-in reduction mechanisms.

Which is the optimum surgical strategy for spondylolisthesis: Reduction or fusion in situ? A meta-analysis from 12 comparative studies

PURPOSE

To compare the clinical outcomes and complications and radiographic outcomes of the two different surgical strategies (arthrodesis in situ and arthrodesis following reduction) for the surgical management of spondylolisthesis.

METHODS

After systematic search the PubMed, Ovid MEDLINE, Cochrane, and Embase databases, comparative studies were selected according to eligibility criteria. Checklists by Furlan and by The Newcastle-Ottawa quality assessment scale (NOS scale) were used to evaluate the risk of bias of the included randomized clinical trials (RCTs) and nonrandomized controlled studies, respectively. The final strength of evidence was expressed as different levels recommended by the GRADE Working Group.

RESULTS

Three RCTs. and nine comparative observational studies were identified. Low-quality evidence indicated that reduction group (RG) was not more effective than fusion in situ group for clinical satisfaction (OR 0.77, 95% CI 0.39-1.54, P = 0.46). and neurologic complication rate (OR 0.89, 95 CI 0.38-2.03, P = 0.78). In secondary outcomes, Low-quality evidence indicated that RG improved fusion rate (OR 2.66, 95% CI 1.15-6.14, P = 0.02). There was no significant difference in the other complication rate (OR 0.89, 95% CI 0.44-1.79, P = 0.63) and blood loss (WMD 14.22, 95% CI -9.53-37.79, P = 0.24) between two groups. Statistical difference was found between the two groups with regard to slipping angle (WMD -6.33, 95% CI -12.60 to -0.06, P = 0.05).

CONCLUSIONS

There was no definite benefit of reduction over fusion in situ in clinical satisfaction rate and neurologic complication rate. The fusion rate significantly improved while the slipping angle considerably decreased postoperation in reduction group.

Is reduction better than arthrodesis in situ in surgical management of low-grade spondylolisthesis? A system review and meta analysis

PURPOSE

To compare the clinical and radiographic outcomes of arthrodesis in situ with arthrodesis after reduction in low-grade spondylolisthesis.

METHODS

We performed a comprehensive search of both observational and randomized clinical trials published up to April 2016 in PubMed, MEDLINE, Cochrane Library, and Embase databases. The outcomes included age, sex, operative time, blood loss, and at least 2 years clinical results of Oswestry disability index (ODI), visual analogue scale (VAS), lumbar lordosis, slippage, fusion rate, the rate of good and excellent and the complication rate. Two authors independently extracted the articles and the predefined data.

RESULTS

Seven eligible studies, involving four RCTs and three cohort studies were included in this systematic review and meta-analysis. Patients who underwent reduction did achieved better slippage correction comparing with arthrodesis in situ (P < 0.00001). However, there was no significant difference in the case of operative time, blood loss, VAS (P = 0.36), ODI (P = 0.50), lumbar lordosis (P = 0.47), the rate of good and excellent (P = 0.84), fusion rate (P = 0.083) and complication rate (P = 0.33) between the arthrodesis in situ group and the reduction group.

CONCLUSIONS

On the basis on this review, arthrodesis after reduction of low-grade spondylolisthesis potentially reduced vertebral slippage. Reduction was neither associated with a longer operative time nor more blood loss. There was no significant difference in the outcomes between reduction and arthrodesis in situ group. Both procedures could be expected to achieve good clinical result.

LEVEL OF EVIDENCE

Therapeutic Level IIa.

Patient-reported and radiographic outcomes of minimally invasive transforaminal lumbar interbody fusion for degenerative spondylolisthesis with or without reduction: A comparative study

This retrospective study aimed to compare the patient-reported outcomes and radiographic assessment of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for degenerative spondylolisthesis with reduction versus in situ fusion. Patients receiving MI-TLIF with reduction were assigned as Group A, and those without reduction were assigned as Group B. Radiographic fusion was assessed using Bridwell's grading criteria. Preoperative and postoperative patient-reported outcomes including visual analogue score (VAS), Oswestry Disability Index (ODI), Japanese Orthopedic Association (JOA) scale and improvement rate were analyzed. There were 41 patients in Group A and 37 patients in Group B. The mean follow-up was 30.78±14.15months in Group A and 28.95±10.75months in Group B (p=0.525). There were no significant differences in hospital stay (p=0.261), estimated blood loss (p=0.639), blood transfusion (p=0.336), operation time (p=0.762) and complications (p=1.00) between the two groups. Radiographic fusion rate was 92.68% (38/41) in Group A, and 81.08% (30/37) in Group B (p=0.110). Significant differences were observed in either 3-month or last follow-up JOA, VAS, and ODI compared with preoperative JOA, VAS, and ODI, respectively (p<0.05). However, there were no significant differences in JOA, VAS, and ODI between the two groups whenever preoperatively, or 3-month postoperatively, or at the last follow-up (p>0.05). According to MacNab criteria, the excellent and good rate was 85.37% in Group A and 86.49% in Group B (p=0.983). MI-TLIF is an effective and satisfactory surgical technique to manage degenerative spondylolisthesis regardless of reduction or not, so routine reduction may not be a requirement in MI-TLIF for degenerative spondylolisthesis.

L5/S1 Fusion Rates in Degenerative Spine Surgery: A Systematic Review Comparing ALIF, TLIF, and Axial Interbody Arthrodesis

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the fusion rate of an anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF), and axial arthrodesis at the lumbosacral junction in adult patients undergoing surgery for 1- and 2-level degenerative spine conditions.

SUMMARY OF BACKGROUND DATA

An L5/S1 interbody fusion is a commonly performed procedure for pathology such as spondylolisthesis with stenosis; however, it is unclear if 1 technique leads to superior fusion rates.

MATERIALS AND METHODS

A systematic search of MEDLINE was conducted for literature published between January 1, 1992 and August 17, 2014. All peer-reviewed articles related to the fusion rate of L5/S1 for an ALIF, TLIF, or axial interbody fusion were included.

RESULTS

In total, 42 articles and 1507 patients were included in this systematic review. A difference in overall fusion rates was identified, with a rate of 99.2% (range, 96.4%-99.8%) for a TLIF, 97.2% (range, 91.0%-99.2%) for an ALIF, and 90.5% (range, 79.0%-97.0%) for an axial interbody fusion (P=0.005). In a paired analysis directly comparing fusion techniques, only the difference between a TLIF and an axial interbody fusion was significant. However, when only cases in which bilateral pedicle screws supported the interbody fusion, no statistical difference (P>0.05) between the 3 techniques was identified.

CONCLUSIONS

The current literature available to guide the treatment of L5/S1 pathology is poor, but the available data suggest that a high fusion rate can be expected with the use of an ALIF, TLIF, or axial interbody fusion. Any technique-dependent benefit in fusion rate can be eliminated with common surgical modifications such as the use of bilateral pedicle screws.

Lever reduction using polyaxial screw and rod fixation system for the treatment of degenerative lumbar spondylolisthesis with spinal stenosis: technique and clinical outcome

Background

The management for degenerative lumbar spondylolisthesis with spinal stenosis remains controversial. Reduction of lumbar spondylolisthesis has been performed via numerous techniques. Most of them need extra reduction assembly.

Methods

In this retrospective analysis, 27 patients of degenerative lumbar spondylolisthesis with spinal stenosis underwent reduction using polyaxial screw and rod constructs and posterolateral fusion. The average age at the time of surgery was 53 ± 3.23 years. The outcome measures consisted of a radiographic assessment of deformity and fusion rate and a clinical assessment of perioperative improvement in low back pain and function. Preoperative and postoperative radiographic evaluation included the percent slip, slip angle, and the lumbar lordosis between L1 and the sacrum measured using the Cobb method. Before surgery and at the final follow-up, the Oswestry Disability Index (ODI) and the visual pain analog scale (VPAS) between 0 (no pain) and 10 (maximal pain) were quantified.

Results

The average follow-up period more than 5 years was available. The mean operative time was 90.19 ± 14.51 min, and the mean blood loss during surgery was 152.59 ± 45.71 ml. The mean length of incision was 4.83 ± 0.63 cm. The average percent slippage and the mean slip angle were, respectively, 19.8 ± 4.49% and 9.69 ± 3.79° before surgery, 5.09 ± 3.40% and 6.39 ± 3.16° after surgery, and 5.67 ± 3.92% and 7.21 ± 3.05° at the last follow-up. The average lumbar lordosis was 36.88 ± 2.64° before surgery, 41.96 ± 1.64° after surgery, and 40.27 ± 1.19° at the final follow-up. No neurologic deficit occurred. Solid fusion was achieved for all cases. Compared with the outcome preoperation, the data improved from 6.56 ± 1.40 to 2.48 ± 1.16 for VPAS pain scores and from 32.22 ± 3.57 to 10.93 ± 4.93 for the ODI at the final follow-up.

Conclusions

Lever slip reduction maneuver techniques using polyaxial screw and rod fixation system was simple and practicable. The treatment outcomes showed satisfactory radiographic characteristics and clinical results. The length of the incision was relatively small with a low intraoperative blood loss and short operation time.

Set screw fracture with cage dislocation after two-level transforaminal lumbar interbody fusion (TLIF): a case report

Introduction

Transforaminal lumbar interbody fusion is a popular procedure used to achieve spondylodesis in patients with degenerative lumbar spinal diseases. We present a rare case of a patient with a set screw fracture with cage dislocation after an open transforaminal lumbar interbody fusion procedure. To the best of our knowledge, this case is the first of its kind to be reported.

Case presentation

A 44-year-old Caucasian woman attended a follow-up appointment at our hospital 3 months after treatment for second-degree lumbar spondylolisthesis (L4/L5) and osteochondrosis (L5/S1) with transforaminal lumbar interbody fusion and dorsal spondylodesis. She complained of severe leg pain on the left side. Her physical examination revealed a normal neurological status, except for paresthesia of the entire left lower limb and at the ball of the left foot. Radiological imaging showed breaking of the set screws with cage dislocation. Surgical revision was then performed with exchange of the whole dorsal instrumentation and the dislocated cage. Six weeks post-operatively, the patient was seen again at our clinic without neurological complaints, except for decreased sensitivity on the dorsum of her left foot. The wound healing and radiological follow-up were uneventful.

Conclusions

Hardware-related complications are rarely seen in patients with open transforaminal lumbar interbody fusion, but must be kept in mind and can potentially cause severe neurological deficits.

Finite element analysis of 3 posterior fixation techniques in the lumbar spine

This study compared the biomechanics of 3 fixation techniques: bilateral pedicle screw (BPS) fixation, unilateral pedicle screw (UPS) fixation, and UPS supplemented with translaminar facet screw (UPS+TLFS) fixation. The study was conducted in an L3-L5 finite element model. Three different finite element models were created by adopting different fixation techniques after removal of the left L3-L4 and L4-L5 facet joints. A 500-N compressive preload combined with 8-NM moment were applied in 3 finite element models with 3 fixation techniques during different movements. Angular displacement and stress distribution were recorded. As described in this article, the UPS model had the most variation in angular displacement, the BPS model was intermediate, and the UPS+TLFS model had the least mobility. Most of the stress accumulated on the body and tail of the pedicle screws and the connecting rods in the UPS and BPS models, but stress accumulated on the rods and the part of the facet joint pierced by the TLFS in the UPS+TLFS model. The middle part of the pedicle screw endured little stress compared with the upper and lower parts. The maximum stress on the fixation devices was highest in the UPS model. The maximum stress in the UPS+TLFS model was the lowest among the 3 models. Biomechanically, UPS+TLFS fixation is superior to either UPS fixation or BPS fixation in improving stability and reducing stress. Bilateral pedicle screw fixation is intermediate, and UPS fixation is inferior.

Evidence-based surgical management of spondylolisthesis: reduction or arthrodesis in situ

BACKGROUND

The role of reduction in the operative management of spondylolisthesis is controversial because of its potential complications, including neurologic deficits, prolonged operative time, and loss of reduction. The aim of this systematic review was to compare arthrodesis in situ and arthrodesis after reduction techniques with respect to clinical and radiographic outcomes and safety.

METHODS

We performed a comprehensive search of the PubMed, Ovid MEDLINE, Cochrane, CINAHL, Google Scholar, and Embase databases with use of the keyword "spondylolisthesis" in combination with "surgery," "reduction," "in situ," "low back pain," "high-grade," "lumbar spine," "lumbar instability," and "fusion."

RESULTS

Eight eligible studies, containing reports of 165 procedures involving reduction followed by arthrodesis and 101 procedures involving arthrodesis in situ without reduction, were identified and included. The procedure involving reduction was associated with a significantly greater decrease in the percentage of slippage (p < 0.002) and slip angle (p < 0.003) compared with arthrodesis in situ. Pseudarthrosis was significantly more frequent in the arthrodesis in situ group compared with the reduction group (17.8% compared with 5.5%, p = 0.004). Neurologic deficits were not significantly more prevalent in the reduction group compared with the arthrodesis in situ group (7.8% compared with 8.9%, p = 0.8).

CONCLUSIONS

On the basis on this review, the reduction of high-grade spondylolisthesis potentially improves overall spine biomechanics by correcting the local kyphotic deformity and reducing vertebral slippage. Reduction was not associated with a greater risk of developing neurologic deficits compared with arthrodesis in situ. Both procedures were associated with good clinical outcomes.

Pedicle-Screw-Based Dynamic Systems and Degenerative Lumbar Diseases: Biomechanical and Clinical Experiences of Dynamic Fusion with Isobar TTL

Dynamic systems in the lumbar spine are believed to reduce main fusion drawbacks such as pseudarthrosis, bone rarefaction, and mechanical failure. Compared to fusion achieved with rigid constructs, biomechanical studies underlined some advantages of dynamic instrumentation including increased load sharing between the instrumentation and interbody bone graft and stresses reduction at bone-to-screw interface. These advantages may result in increased fusion rates, limitation of bone rarefaction, and reduction of mechanical complications with the ultimate objective to reduce reoperations rates. However published clinical evidence for dynamic systems remains limited. In addition to providing biomechanical evaluation of a pedicle-screw-based dynamic system, the present study offers a long-term (average 10.2 years) insight view of the clinical outcomes of 18 patients treated by fusion with dynamic systems for degenerative lumbar spine diseases. The findings outline significant and stable symptoms relief, absence of implant-related complications, no revision surgery, and few adjacent segment degenerative changes. In spite of sample limitations, this is the first long-term report of outcomes of dynamic fusion that opens an interesting perspective for clinical outcomes of dynamic systems that need to be explored at larger scale.

The pathophysiology, diagnosis, and management of stress fractures in postmenopausal women

INTRODUCTION

Increasing numbers of elderly individuals are now participating in marathons. With increased participation in running, there has been an increase in the diagnosis of stress fractures in the elderly population. Postmenopausal women are particularly at risk due to osteoporosis.

DISCUSSION

There are numerous risk factors for stress fractures in the literature that need to be addressed to reduce the risk of injury and recurrence in postmenopausal women. Diagnostic tests include plain radiograph, ultrasound, therapeutic ultrasound, computed tomography scan, and isotope bone scans; however, magnetic resonance imaging remains the gold standard. Treatment is based on risk stratification, with high-risk fractures managed aggressively with either non-weightbearing or surgical intervention. Although exercise is prescribed as a well-recognized treatment modality of poor bone density, balance is essential to avoid precipitating stress fractures.

CONCLUSION

Optimal exercise programs should balance the beneficial effect of increasing bone mineral density through exercise with the detrimental effect of stress fractures. A useful algorithm is presented in this article to guide the clinician in the diagnosis and management of appropriate investigations and management of such injuries. This review article describes the pathophysiology and provides a review of the literature to determine the latest diagnostic and treatment strategies for this unique population.

Segmental lumbar sagittal correction after bilateral transforaminal lumbar interbody fusion

OBJECT

In this paper the authors sought to determine the segmental lumbar sagittal contour change after bilateral transforaminal lumbar interbody fusion (TLIF).

METHODS

Between March 2007 and October 2010, 42 consecutive patients (57 levels) underwent bilateral TLIF. Standard preoperative and 6-week postoperative standing lumbar spine radiographs were examined. Preoperative and postoperative segmental lordosis was determined by manual measurements using the Cobb method. The difference between the preoperative and postoperative values were calculated and analyzed for statistical significance.

RESULTS

The mean preoperative segmental alignment was 8.1°. The mean postoperative alignment was 15.3°, with a mean correction of 7.2° per segment. The largest gain in lordosis was obtained at the L5-S1 level (10.1°). There was a significant difference between the preoperative and postoperative values (p = 5 × 10(-9)). There was no significant difference in mean segmental correction between levels. Improvement in lordosis was higher in multilevel fusions (9.8°) than in single-level fusions (5.2°) (p = 0.047). There was an inverse correlation between preoperative sagittal lordosis measurement and change in lordosis (r = -0.599).

CONCLUSIONS

A significant improvement in lumbar lordosis can be gained by preforming bilateral facetectomies in TLIF with posterior compression. This procedure provides an additional option to a spine surgeon's armamentarium in dealing with significant lumbar sagittal plane deformities.