Comparison of unilateral versus bilateral pedicle screw fixation with cage fusion in degenerative lumbar diseases: a meta-analysis

Minimally invasive transforaminal lumbar interbody fusion with unilateral pedicle screw fixation (UNILF): outcomes at 7 years

PURPOSE

To assess clinical, functional and radiographical results of one-level minimally invasive transforaminal interbody fusion with unilateral pedicle screw fixation (UNILIF) in the treatment of stable lumbar degenerative diseases with a minimum of 5 years of follow-up.

MATERIAL AND METHOD

From January 2012 to December 2016, clinical and radiological data of patients with degenerative lumbar disease managed by UNILIF were prospectively collected. Patients with a follow-up that ended before 5 years were excluded. SF-12, Oswestry disability index (ODI) and visual analog scale (VAS) were collected preoperatively, at 2 years and at the last follow-up. A full-spine standing radiograph was performed at each follow-up appointment.

RESULTS

Mean operative time was 74.7 (± 19) minutes, mean blood loss was 131.1 (± 207) ml and mean follow-up was 7.5 (± 1.7) years. All functional scores and VAS were significantly improved between the preoperative and the 2 years postoperative. Between the 2 years postoperative and the last follow-up ODI and VAS continued to significantly improved. Fusion rate was 98.6% on radiographic analysis at follow-up.

CONCLUSION

UNILIF method is a safe and effective surgical strategy. It provides a durable improvement in functional score over 7 years of follow-up with a stable radiological correction over time.

Is unilateral pedicle screw fixation as effective as bilateral pedicle screw fixation in transforaminal lumbar interbody fusion: a meta-analysis of randomized controlled trials

PURPOSE

This meta-analysis aimed to investigate whether unilateral pedicle screw fixation (UPSF) is comparable to bilateral pedicle screw fixation (BPSF) in transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative diseases.

METHODS

Up to September 2022, established electronic literature databases including PubMed, Web of Science, EMBASE, and the Cochrane Library were systematically searched. Randomized controlled trials (RCTs) published in English that compared the efficacy of UPSF versus BPSF in TLIF were included. The methodological quality was evaluated, relevant data was extracted, and suitable meta-analysis was carried out. Data of fusion rate, complications, cage migration, visual analog scale (VAS), and Oswestry Disability Index (ODI), total blood loss (TBL), operation time, and hospital stay were extracted and analyzed. Pooled mean differences and risk ratio (RR) along with 95% confidence intervals (95% CI) were calculated for the results.

RESULTS

Ten RCTs including 614 patients (UPSF = 294, BPSF = 320) were included in our meta-analysis. There were no significant differences in terms of fusion rate, VAS (VAS-BP and VAS-LP), ODI, complications, or hospital stay between UPSF and BPSF groups (P > 0.05, respectively). The UPSF group clearly had the advantage of less blood loss (SMD = -2.99, 95% CI [-4.54, -1.45], P = 0.0001) and operation time (SMD = -2.05, 95% CI [-3.10, -1.00], P = 0.0001). However, UPSF increased cage migration more than BPSF (10.7% vs 4.8%, RR = 2.23, 95% CI [1.07, 4.65],  P = 0.03).

CONCLUSION

According to the findings of this meta-analysis, UPSF is just as effective as BPSF in TLIF and may reduce blood loss and operation time. Nevertheless, UPSF may result in more cage migration than BPSF.

A biomechanical comparison of posterior fixation approaches in lumbar fusion using computed tomography based lumbosacral spine modelling

Extreme lateral interbody fusion (XLIF) may be performed with a standalone interbody cage, or with the addition of unilateral or bilateral pedicle screws; however, decisions regarding supplemental fixation are predominantly based on clinical indicators. This study examines the impact of posterior supplemental fixation on facet micromotions, cage loads and load-patterns at adjacent levels in a L4-L5 XLIF at early and late fusion stages. CT data from an asymptomatic subject were segmented into anatomical regions and digitally stitched into a surface mesh of the lumbosacral spine (L1-S1). The interbody cage and posterior instrumentation (unilateral and bilateral) were inserted at L4-L5. The volumetric mesh was imported into finite element software for pre-processing, running nonlinear static solves and post-processing. Loads and micromotions at the index-level facets reduced commensurately with the extent of posterior fixation accompanying the XLIF, while load-pattern changes observed at adjacent facets may be anatomically dependent. In flexion at partial fusion, compressive stress on the cage reduced by 54% and 72% in unilateral and bilateral models respectively; in extension the reductions were 58% and 75% compared to standalone XLIF. A similar pattern was observed at full fusion. Unilateral fixation provided similar stability compared to bilateral, however there was a reduction in cage stress-risers with the bilateral instrumentation. No changes were found at adjacent discs. Posterior supplemental fixation alters biomechanics at the index and adjacent levels in a manner that warrants consideration alongside clinical information. Unilateral instrumentation is a more efficient option where the stability requirements and subsidence risk are not excessive.

Safety and efficacy of unilateral and bilateral pedicle screw fixation for lumbar degenerative diseases by transforaminal lumbar interbody fusion: An updated systematic review and meta-analysis

Background

The purpose of this study was to compare the safety and efficacy of unilateral vs. bilateral pedicle screw fixation (BPSF) for lumbar degenerative diseases.

Methods

Electronic databases including PubMed, Web of science, the Cochrane Library, Scopus, MEDLINE, EMBASE, EBSCO were searched by computer. The deadline was set for June 1, 2022. This study included all high-quality randomized controlled trials (RCTs), prospective clinical controlled studies (PRO), and retrospective studies (Retro) that compared unilateral and bilateral pedicle screw fixation in the treatment of lumbar degenerative diseases. Revman5.3 software was used for meta-analysis after two researchers independently screened the literature, extracted data, and assessed the risk of bias in the study.

Results

Fourteen studies with a total of 1,086 patients were included. Compared with BPSF, unilateral pedicle screw fixation (UPSF) has shorter operation time and hospital time, and less blood loss and operation cost, operation time [SMD = −1.75, 95% CI (−2.46 to −1.03), P < 0.00001], hospital time [SMD = −1.10, 95% CI (−1.97 to −0.22), P = 0.01], Blood loss [SMD = −1.62, 95% CI (−2.42 to −0.82), P < 0.0001], operation cost [SMD = −14.03, 95% CI (−20.08 to −7.98), P < 0.00001], the ODI after bilateral pedicle screw fixation was lower, and the degree of lumbar dysfunction was lighter, [SMD = 0.19, 95% CI (0.05–0.33), P = 0.007], better fusion effect, fusion rate [RR=0.95, 95% CI (0.91–1.00), P = 0.04]. VAS-Low back pain [SMD = 0.07, 95% CI (−0.07–0.20), P = 0.35], VAS-Leg pain [SMD = 0.18, 95% CI (−0.00–0.36), P = 0.05], SF-36 [SMD = 0.00, 95% CI (−0.30–0.30), P = 1.00], complications rate [RR = 0.94, 95% CI (0.9154–1.63), P = 0.82], the overall difference was not statistically significant.

Conclusions

Currently limited evidence suggests that UPSF significantly reduces blood loss, significantly shortens the operative time and hospital stay, and reduces blood loss and costs. After BPSF, the ODI was lower, the degree of lumbar spine dysfunction was lower, and the fusion rate was significantly higher. The VAS, SF-36, and complications scores of the two groups were comparable, and there was no significant clinical difference.

Unilateral versus bilateral pedicle screw fixation with transforaminal lumbar interbody fusion for treatment of lumbar foraminal stenosis

BACKGROUND CONTEXT

Transforaminal lumbar interbody fusion (TLIF) with bilateral pedicle screw fixation (BPSF) is an effective treatment for lumbar foraminal stenosis (LFS). However, the effects of TLIF with unilateral pedicle screw fixation (UPSF) on LFS treatment have not been clearly elucidated.

PURPOSE

We conducted this study to compare clinical outcomes and radiographic results of TLIF with UPSF and BPSF 2 years after the surgical treatment.

DESIGN

Prospective randomized study.

PATIENT SAMPLE

This study included 23 patients undergoing TLIF with UPSF and 25 patients undergoing TLIF with BPSF.

OUTCOME MEASURES

Clinical outcomes were evaluated by visual analog scale (VAS) for low back pain and leg pain and Oswestry Disability Index (ODI) score. Radiographic outcomes included foraminal height, disc space height, segmental lordosis, and final fusion rates.

METHODS

The clinical and radiographic outcomes were compared between the UPSF and BPSF group. The postoperative improvements were evaluated in either group. Intraoperative data such as duration of operation and estimated blood loss were collected. This study was registered at clinicaltrials.gov.

RESULTS

Analysis of the VAS and ODI scores showed significant improvements in clinical outcomes within each group. No significant differences between the 2 groups were noted in the improvements of the VAS and ODI scores. The mean operative duration and blood loss were significantly greater in the BPSF group than in the UPSF group. There were significant improvements in the height of the foramen and intervertebral space and segmental lordosis in both groups, while there was no significant difference between the groups in amount of the improvements. No significant difference was found in the final fusion rates.

CONCLUSIONS

TLIF is an appropriate procedure for LFS treatment. With balanced intervertebral support using a cage, UPSF could achieve similar and satisfactory effects on lumbar segmental stability and fusion compared to BPSF. The unilateral approach appears to be associated with slightly shorter operative time and less blood loss.

Biomechanical Evaluation of Transforaminal Lumbar Interbody Fusion with Coflex-F and Pedicle Screw Fixation: Finite Element Analysis of Static and Vibration Conditions

OBJECTIVE

To investigate the biomechanics of transforaminal lumbar interbody fusion (TLIF) with interspinous process device (IPD) or pedicle screw fixation under both static and vibration conditions by the finite element (FE) method.

METHOD

A validated FE model of the L1-5 lumbar spine was used in this study. This FE model derived from computed tomography images of a healthy female adult volunteer of appropriate age. Then the model was modified to simulate L3-4 TLIF. Four conditions were compared: (i) intact; (ii) TLIF combined with bilateral pedicle screw fixation (BPSF); (iii) TLIF combined with U-shaped IPD Coflex-F (CF); and (iv) TLIF combined with unilateral pedicle screw fixation (UPSF). The intact and surgical FE models were analyzed under static and vibration loading conditions respectively. For static loading conditions, four motion modes (flexion, extension, lateral bending, and axial rotation) were simulated. For vibration loading conditions, the dynamic responses of lumbar spine under sinusoidal vertical load were simulated.

RESULT

Under static loading conditions, compared with intact case, BPSF decreased range of motion (ROM) by 92%, 95%, 89% and 92% in flexion, extension, lateral bending and axial rotation, respectively. While CF decreased ROM by 87%, 90%, 69% and 80%, and UPSF decreased ROM by 84%, 89%, 66% and 82%, respectively. Compared with CF, UPSF increased the endplate stress by 5%-8% in flexion, 7%-10% in extension, 2%-4% in lateral bending, and decreased the endplate stress by 16%-19% in axial rotation. Compared with CF, UPSF increased the cage stress by 9% in flexion, 10% in extension, and decreased the cage stress by 3% in lateral bending, and 13% in axial rotation. BPSF decreased the stress responses of endplates and cage compared with CF and UPSF. Compared BPSF, CF decreased the facet joint force (FJF) by 6%-13%, and UPSF decreased the FJF by 4%-12%. During vibration loading conditions, compared with BPSF, CF reduced maximum values of the FJF by 16%-32%, and vibration amplitudes by 22%-35%, while UPSF reduced maximum values by 20%-40%, and vibration amplitudes by 31%-45%.

CONCLUSION

Compared with other surgical models, BPSF increased the stability of lumbar spine, and also showed advantages in cage stress and endplate stress. CF showed advantages in IDP and FJF especially during vertical vibration, which may lead to lower risk of adjacent segment degeneration. CF may be an effective alternative to pedicle screw fixation in TLIF procedures.

Awake Percutaneous Fixation for Unstable Fractures of the Spine in High-risk Patients: A Retrospective Study

INTRODUCTION

Unstable fractures in sick or elderly patients are on the rise. These patients who are at high risk for surgery present a challenge for surgeons and anesthesiologists. In patients with American Society of Anesthesiologists (ASA) scores 3 to 4, the risk is even higher because of the high rate of intraoperative complications.

METHODS

All patients with ASA scores 3 to 4 who presented with unstable fractures of the spine to a level-one trauma center were assessed, and they underwent awake spinal percutaneous fixation, with mild sedation and local anesthesia. Demographics, radiology, and the outcome were collected.

RESULTS

Nineteen patients were operated between the years 2019 and 2021. Average follow-up was 12 months (range 8 to 24 months); six patients were female and 13 males. The average age was 77.7 years; the ASA score was 3 to 4 in all patients. There were 10 extension-type injuries, six unstable burst injuries, two chance fractures, and one teardrop fracture. All patients underwent unilateral fixation, and just one patient underwent bilateral fixation; cement augmentation was done in 16 of the patients. No neurologic complication was observed. One case of infection presented 4 months after surgery. All patients were discharged ambulating.

CONCLUSIONS

Awake fixation in extreme cases is safe and feasible; a dedicated team including an anesthesiologist and radiologist is needed to treat these cases safely and quickly.

Minimally invasive unilateral lumbar interbody fusion (UNILIF) in over-80-year-olds. Continuous series of 42 patients at 1.4 years' follow-up

INTRODUCTION

In lumbar stenosis, surgery aims to improve quality of life in increasingly elderly patients. Minimally invasive techniques better suit the requirements of elderly patients with increasing functional demand.

HYPOTHESIS

The UNILIF unilateral lumbar interbody fusion technique improves functional scores at 1 year in over-80 year-olds, with low morbidity.

METHOD

Patients undergoing minimally invasive decompression with transforaminal lumbar interbody fusion (TLIF) associated to unilateral pedicle screwing for degenerative lumbar stenosis were analyzed at a minimum 1 year's follow-up. SF12, Oswestry Disability Index (ODI) and Quebec scores and sagittal spinopelvic radiographic parameters were assessed at follow-up. Surgical and general complications were also collated.

RESULTS

In all, 42 patients (64.3% female; mean age, 83.7±2.9 years) were treated by UNILIF at levels L2-L3 (3.8%), L3-L4 (15.4%), L4-L5 (71.2%) and L5-S1 (9.6%). Mean follow-up was 520±226 days (range, 340-1166 days). Mean preoperative SF12 score was 77.5±10.9, with significant improvement at last follow-up: 81.9±138 (p<0.05). Mean preoperative ODI was 44.4%±14.0, with significant improvement at last follow-up: 32.4%±13.3 (p<0.001). Mean preoperative Quebec score was 42.9±19.9, with significant improvement at last follow-up: 28.5±21.9 (p<0.001). Spinopelvic sagittal balance was not affected by the UNILIF procedure. There were no cases of infection or severe general complications during follow-up, although 2 cases of non-union required revision surgery.

CONCLUSION

Lumbar stenosis surgery by UNILIF improved functional scores at 1 year, with low morbidity. It is a suitable strategy for degenerative lumbar stenosis in elderly patients.

LEVEL OF EVIDENCE

IV, non-comparative cohort study.

Unilateral versus bilateral pedicle screw fixation in lumbar fusion: A systematic review of overlapping meta-analyses

OBJECTIVES

To carry out a systematic review on the basis of overlapping meta-analyses that compare unilateral with bilateral pedicle screw fixation (PSF) in lumbar fusion to identify which study represents the current best evidence, and to provide recommendations of treatment on this topic.

METHODS

A comprehensive literature search in PubMed, Embase, and the Cochrane Library databases was conducted to identify meta-analyses that compare unilateral with bilateral PSF in lumbar fusion. Only meta-analyses exclusively covering randomized controlled trials were included. Study quality was evaluated using the Oxford Levels of Evidence and Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Then, the Jadad decision algorithm was applied to select the highest-quality study to represent the current best evidence.

RESULTS

A total of 9 studies with Level II of evidence fulfilled the eligibility criteria and were included. The scores of AMSTAR criteria for them varied from 5 to 9 (mean 7.78). The current best evidence detected no significant differences between unilateral and bilateral PSF for short-segment lumbar fusion in the functional scores, length of hospital stay, fusion rate, and complication rate. However, unilateral PSF involved a remarkable decrease in operative time and blood loss but increase of cage migration when compared with bilateral PSF.

CONCLUSIONS

According to this systematic review, unilateral PSF is an effective method of fixation for short-segment lumbar fusion, has the advantages of reduced operative time and blood loss over bilateral PSF, but increases the risk of cage migration.

Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Oblique Lumbar Interbody Fusion

OBJECTIVE

To compare clinical and radiologic outcomes of unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) fixations after single-level oblique lateral interbody fusion procedures.

METHODS

This retrospective study included 74 patients receiving single-level oblique lateral interbody fusion at L3-4 or L4-5 (June 2014 to June 2017). These patients were divided into BPS (n = 36) and UPS (n = 38) groups. Perioperative outcomes included operative time, blood loss, medical expenses, and complication rates. Radiologic outcomes included fusion rates and cage subsidence rates. Clinical outcomes included disability measured by the Oswestry Disability Index and pain measured by the visual analog scale.

RESULTS

The operative time was significantly shorter in the UPS group (76.2 ± 4.4 minutes) compared with the BPS group (127.0 ± 5.6 minutes, P < 0.001). There was a significant between-group difference in medical expenses ($11,044.8 ± $470.7 in UPS group vs. $15,018.4 ± $547.1 in BPS, P < 0.001). Blood loss and hospital stay did not differ between groups. Oswestry Disability Index and visual analog scale scores significantly decreased in both groups at different time points postoperatively compared with preoperatively. The UPS group had lower Oswestry Disability Index and visual analog scale scores than the BPS group at 7 days postoperatively, but no between-group difference was found after 1-month follow-up. Fusion rate was 86.8% in UPS group and 91.7% in BPS group (P > 0.05). Cage subsidence rates did not differ between groups.

CONCLUSIONS

Oblique lateral interbody fusion with UPS fixation is an effective and reliable option for single-level lumbar diseases. Compared with BPS fixation, it resulted in less blood loss, required less operative time, and had comparable effects on radiologic and clinical outcomes.

Cage migration after unilateral instrumented transforaminal lumbar interbody fusion and associated risk factors: a modified measurement method

Objective

In this retrospective study, a modified measurement method was used to analyze cage migration during follow-up after unilateral instrumented transforaminal lumbar interbody fusion (TLIF) and identify associated factors.

Methods

We retrospectively evaluated 75 patients who had been treated with unilateral instrumented TLIF. Cage migration was quantitatively defined as anterior–posterior or lateral displacement of the cage.

Results

Five patients had significant cage migration (6.7%), but none developed severe neural symptoms during follow-up or underwent reoperation. The cages tended to migrate posteriorly or toward the side of surgery. The initial cage position and patient age were strongly associated with migration. Migration was less frequent when the cages were initially placed closer to the side of surgery. Patients of advanced age were more likely to develop anterior–posterior migration than were young patients.

Conclusion

Cage migration is related to the initial position of the cage. Particular attention is required when performing unilateral instrumented TLIF in patients of advanced age because they are most likely to develop cage migration. Quantification of cage migration is an effective method of exploring the associated factors.

Does the Cage Position in Transforaminal Lumbar Interbody Fusion Determine Unilateral versus Bilateral Screw Placement?: A Review of the Literature

This literature review examines the relative placement of the interbody cage with respect to the unilateral screw construct to address the need for bilateral screw placement versus unilateral screw placement. Transforaminal lumbar interbody fusion (TLIF) has become a widely used technique for correcting lumbar intervertebral pathologies. This review addresses the necessity for further study on the effects of the relative position of intervertebral cage placement on the outcome of lumbar spine surgery after TLIF with unilateral pedicle screw fixation. Previous studies have addressed various factors, including posterior screw fixation, cage size, cage shape, and number of levels fused, that impact the biomechanics of the lumbar spine following TLIF. A simple survey of the literature was conducted. A search of the English literature was conducted using the keywords ‘TLIF,’ ‘transforaminal lumbar interbody fusion,’ ‘graft placement,’ ‘graft position,’ ‘cage position,’ ‘cage placement,’ ‘unilateral pedicle screw,’ ‘unilateral TLIF cage placement,’ ‘lumbar biomechanics,’ ‘lumbar stability,’ ‘lumbar fusion,’ and ‘lumbar intervertebral cage’ with various combinations of the operators ‘AND’ and ‘OR’ and no date restrictions. Seventeen articles in the English literature that were most relevant to this research question were identified. To the best of our knowledge, there are no published data addressing the effects of cage placement relative to the unilateral screw on lumbar stability in TLIF with unilateral pedicle screw fixation. Investigation of the effects of cage placement is, thus, warranted to achieve optimal clinical outcomes in patients undergoing TLIF with unilateral pedicle screw fixation.

Is unilateral pedicle screw fixation superior than bilateral pedicle screw fixation for lumbar degenerative diseases: a meta-analysis

Background

To investigate whether unilateral pedicle screw fixation is superior than bilateral pedicle screw fixation for lumbar degenerative diseases.

Methods

Electronic databases including PubMed, Embase, and the Cochrane Library up to August 2018 were searched. All the high-quality randomized controlled trials (RCTs) and prospective clinical controlled studies comparing the unilateral pedicle screw fixation and bilateral pedicle screw fixation for lumbar degenerative diseases were enrolled in this study. Fusion rate was the main outcome. Stata 12.0 was used for the meta-analysis.

Results

Twelve RCTs including 808 patients (unilateral pedicle screw fixation = 393, bilateral pedicle screw fixation = 415) were included in our meta-analysis. There was a significant difference between unilateral pedicle screw fixation and bilateral pedicle screw fixation in terms of the fusion rate (risk ratio (RR) = 0.96, 95%CI [0.92, 1.00], P = 0.073), visual analog scale (VAS) at final follow-up, Oswestry Disability Index (ODI), Japanese Orthopedic Association scores (JOA), short-form health survey (SF-36), and length of hospital stay. Compared with bilateral pedicle screw fixation, unilateral pedicle screw fixation was associated with a reduction of the total blood loss and operation time (P < 0.05). Unilateral pedicle screw fixation was associated with an increase of the cage migration than bilateral pedicle screw fixation (17.1% vs 7.1%, RR = 2.40, 95% CI = 1.17 to 4.93; P = 0.017).

Conclusions

Unilateral pedicle screw fixation and bilateral pedicle screw fixation has similar fusion rate when treating for lumbar degenerative diseases. Our meta-analysis suggested that compared with bilateral pedicle screw fixation, unilateral pedicle screw fixation significantly reduced total blood loss and operation time for lumbar degenerative diseases. The use of unilateral pedicle screw for lumbar degenerative diseases increases the cage migration.

Comparison of unilateral pedicle screw fixation and interbody fusion with PEEK cage vs. standalone expandable fusion cage for the treatment of unilateral lumbar disc herniation

INTRODUCTION

This study was conducted to compare the clinical effects of unilateral pedicle screw fixation and interbody fusion with PEEK cage (UPSFC) and standalone expandable fusion cage (SAEFC) on unilateral lumbar disc herniation.

MATERIAL AND METHODS

From September 2011 to July 2014, a respective investigation was performed on 130 lumbar disc herniation patients treated with SAEFC or UPSFC. The hospital stay, operating time, blood loss, Japanese orthopaedic association scores (JOA), and visual analogue score (VAS) in the two groups were compared using Student's t-test.

RESULTS

The average of follow-up time was 25.6 ±6.4 and 25.2 ±5.8 months, respectively. No significant difference in the postoperative hospitalizsation, intraoperative blood loss, operative time, and postoperative fusion rate was detected between the two groups. VAS score in the UPSFC group was significantly lower than in the SAEFC group at 6 and 12 months after operation (p = 0.014, p = 0.004). X-ray images indicated that the subsidence rate was 8.1% (5/62) in the SAEFC group, while no subsidence was detected in UPSFC group 12 month after operation.

CONCLUSIONS

Both SAEFC and UPSFC are effective techniques. UPSFC may be a better choice for patients with lumbar disc herniation and unilateral limb symptoms of nerve root in view of the advantages of better low back pain relief and low subsidence rate.

Anterior and Lateral Lumbar Interbody Fusion With Supplemental Interspinous Process Fixation: Outcomes from a Multicenter, Prospective, Randomized, Controlled Study

Background

Rigid interspinous process fixation (ISPF) has received consideration as an efficient, minimally disruptive technique in supporting lumbar interbody fusion. However, despite advantageous intraoperative utility, limited evidence exists characterizing midterm to long-term clinical outcomes with ISPF. The objective of this multicenter study was to prospectively assess patients receiving single-level anterior (ALIF) or lateral (LLIF) lumbar interbody fusion with adjunctive ISPF.

Methods

This was a prospective, randomized, multicenter (11 investigators), noninferiority trial. All patients received single-level ALIF or LLIF with supplemental ISPF (n = 66) or pedicle screw fixation (PSF; n = 37) for degenerative disc disease and/or spondylolisthesis (grade ≤2). The randomization patient ratio was 2:1, ISPF/PSF. Perioperative and follow-up outcomes were collected (6 weeks, 3 months, 6 months, and 12 months).

Results

For ISPF patients, mean posterior intraoperative outcomes were: blood loss, 70.9 mL; operating time, 52.2 minutes; incision length, 5.5 cm; and fluoroscopic imaging time, 10.4 seconds. Statistically significant improvement in patient Oswestry Disability Index scores were achieved by just 6 weeks after operation (P < .01) and improved out to 12 months for the ISPF cohort. Patient-reported 36-Item Short Form Health Survey and Zurich Claudication Questionnaire scores were also significantly improved from baseline to 12 months in the ISPF cohort (P < .01). A total of 92.7% of ISPF patients exhibited interspinous fusion at 12 months. One ISPF patient (1.5%) required a secondary surgical intervention of possible relation to the posterior instrumentation/procedure.

Conclusion

ISPF can be achieved quickly, with minimal tissue disruption and complication. In supplementing ALIF and LLIF, ISPF supported significant improvement in early postoperative (≤12 months) patient-reported outcomes, while facilitating robust posterior fusion.

Incidence and risk factors of posterior cage migration following decompression and instrumented fusion for degenerative lumbar disorders

The aim of this study was to explore the incidence and risk factors for posterior cage migration (PCM) following decompression and instrumented fusion for degenerative lumbar disorders, and hope to provide references in decision making and surgical planning for spine surgeons.By retrieving the medical records from January 2011 to December 2015, 286 patients were retrospectively reviewed. According to the occurrence of PCM, patients were divided into 2 groups: PCM group and non-PCM (N-PCM). To investigate risk values for PCM, 3 categorized factors were analyzed statistically: patient characteristics: age, sex, body mass index, bone mineral density, duration of disease, diagnosis, comorbidity, smoke; surgical variables: surgery time, blood loss, surgical strategy, cage morphology, cage size, surgical segment, fusion number, source of bone graft, surgeon experience; radiographic parameters: preoperative lumbar lordosis, correction of lumbar lordosis, preoperative lumbar mobility, preoperative intervertebral height, change of intervertebral height, Modic changes, paraspinal muscle degeneration.PCM was detected in 18 of 286 patients (6.3%) at follow-up. There was no statistically significant difference between the 2 groups in patient characteristics, except diagnosis, as lumbar spondylolisthesis was more prevalent in PCM group than that in N-PCM group. There was no difference between the 2 groups in surgical variables, except cage size and surgeon experience, as size of cage was smaller in PCM group than that in N-PCM group, and the surgeons with less experience (less than 3 years) were more prevalent in PCM group than that in N-PCM group. There was no statistically significant difference between 2 groups in radiographic parameters. Logistic regression model revealed that less than 3 years of surgeons' experience, small cage size, and lumbar spondylolisthesis were independently associated with PCM.For patients with lumbar spondylolisthesis, they should be fully informed about the risk of PCM before operation. While for spinal surgeons, large cage should be preferred, and careful manipulation should be adopted, especially for new learners with less than 3-year experience of fusion surgery.

Unilateral versus bilateral pedicle screw fixation with posterior lumbar interbody fusion for lumbar degenerative diseases: A meta-analysis

BACKGROUND

Both unilateral pedicle screw fixation with posterior lumbar interbody fusion (PLIF) and bilateral pedicle screw fixation with PLIF are used to treat lumbar degenerative diseases (LDD). However, which one is a better treatment for LDD remains considerable controversy. Therefore, the focus of this meta-analysis was to assess the merits and shortcomings of efficacy of these 2 surgical procedures for LDD.

METHODS

An extensive search of literature was performed in Pubmed/MEDLINE, Embase, CNKI, and WANFANG databases on unilateral versus bilateral pedicle screw fixation with PLIF fusion for LDD, from January 2007 to January 2017 and language was restricted to Chinese or English. The following variables were extracted: blood loss, operation time, length of hospital stay, Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) and Oswestry disability index (ODI) scores, fusion rate, total complications, infection, dural injury, and nerve injury. Data analysis was conducted with RevMan 5.3 and STATA 12.0.

RESULTS

A total of 11 studies containing 844 patients were included in our study. The results showed that unilateral is better than bilateral pedicle screw fixation with PLIF in blood loss (P < .00001), operation time (P < .00001), the length of hospital stay (P = .003), and the final follow-up ODI scores (P = .04). However, there are no significant differences in JOA, VAS, and preoperative ODI scores. There are also no significant differences in fusion rate and complications (all P > .05).

CONCLUSION

Based on our meta-analysis, our results suggest that both unilateral pedicle screw fixation with PLIF and bilateral pedicle screw fixation with PLIF for LDD have effective results in clinical outcomes. Both 2 methods may result in clinical improvement and similar outcomes of fusion rate and complications; However, compared with bilateral fixation, unilateral fixation produces more satisfactory efficacy in the blood loss and the operation time.

Pedicle screw fixation combined with intermediate screw at the fracture level for treatment of thoracolumbar fractures: A meta-analysis

BACKGROUND

Use of a pedicle screw at the level of fracture, also known as an intermediate screw, has been shown to improve clinical results in managing thoracolumbar(TL) fractures, but there is a paucity of powerful evidence to support the claim. The aim of this study was to compare outcomes between pedicle screw fixation combined with intermediate screw at the fracture level and conventional pedicle screw fixation (one level above and one level below the fracture level) for thoracolumbar (TL) fractures.

METHODS

A meta-analysis of cohort studies was conducted between pedicle screw fixation combined with intermediate screw at the fracture level (combined screw group) and conventional pedicle screw fixation (conventional group) for the treatment of TL fractures from their inception to December 2015. An extensive search of studies was performed in PubMed, Medline, Embase, and the Cochrane library. The following outcome measures were extracted: visual analogue scale (VAS), operation time and intraoperative blood loss, Cobb angle and anterior vertebral height (AVH), and complications. Data analysis was conducted with RevMan 5.3.5.

RESULTS

From 10 relevant studies identified, 283 patients undergoing pedicle screw fixation combined with intermediate screw at the fracture level were compared with 285 conventional pedicle screw procedures. The pooled analysis showed that there was statistically significant difference in terms of postoperative Cobb angle (95% confidence interval (CI), -3.00, -0.75; P = 0.001) and AVH (95% CI, 0.04, 12.23; P = 0.05), correction loss (Cobb angle: P < 0.0001; AVH: P < 0.0001) and implant failure rate (95% CI, 0.06, 0.62; P = 0.006), and blood loss (W 95% CI, 2.22, 23.60; P = 0.02) between 2 groups. But in terms of other complications, there were no differences between 2 groups (95% CI, 0.23, 2.04; P = 0.50). No difference was found in operation time (95% CI, -5.36, 14.67; P = 0.36) and VAS scores (95% CI, -0.44, 0.01; P = 0.06).

CONCLUSIONS

The combined screw fixation technique was associated with better reduction of the fractured vertebrae, less correction loss in the follow-up, and lower implant failure rate. Given the lack of robust clinical evidence, these findings warrant verification in large prospective registries and randomized trials with long-term follow-up.

Unilateral Pedicle Screw Fixation with Bone Graft vs. Bilateral Pedicle Screw Fixation with Bone Graft or Cage: A Comparative Study

BACKGROUND

The aim of this study was to explore the clinical efficacy of unilateral pedicle screw fixation with bone graft (UPSFB) in treating single-segment lumbar degenerative diseases (LDD), as compared to bilateral pedicle screw fixation with bone graft (BPSFB) or with cage (BPSFC).

MATERIAL/METHODS

Medical records were retrospectively collected between 01/2010 and 02/2015 in Longyao County Hospital. According to surgical methods used, all patients were divided into 3 groups: UPSFB group, BPSFB group, and BPSFC group. Clinical outcomes were evaluated by blood loss, blood transfusion, duration of operation, hospital stay, postoperative complications, interbody fusion rate, reoperation rate, medical expenses, patient satisfaction survey, and JOA score.

RESULTS

Ninety-five patients were included and underwent 2.5-year follow-up, with 7 patients lost to regular follow-up. As compared to the BPSFB group and BPSFC group, the UPSFB group had less blood loss and less blood transfusion, as well as shorter hospital stay (p<0.05). Medical expenses were far lower in the UPSFB group (p<0.001). There were no significant differences among the 3 groups in postoperative complications, interbody fusion rate, reoperation rate, JOA score, and patient satisfaction (all p>0.05).

CONCLUSIONS

As compared to BPSFB and BPSFC, UPSFB has the same reliability and effectiveness in treating single-segment LDD with unilateral radicular symptoms in a single lower extremity, with the additional advantage being less expensive.