Pyogenic lumbar spondylodiscitis treated with transforaminal lumbar interbody fusion: safety and outcomes

Purpose

Our aim was to study the safety and outcomes of posterior instrumentation and transforaminal lumbar interbody fusion (TLIF) for treating pyogenic lumbar spondylodiscitis.

Methods

Retrospective analysis was performed on prospectively collected data of 27 consecutive cases of lumbar pyogenic spondylodiscitis treated with posterior instrumentation and TLIF between January 2009 and December 2012. Cases were analysed for safety, radiological and clinical outcomes of transforaminal interbody fusion using bone graft?±?titanium cages. Interbody metallic cages with bone graft were used in 17 cases and ten cases used only bone graft. Indications for surgical treatment were failed conservative management in 17, neurodeficit in six and significant bony destruction in four.

Results

There were no cases reporting cage migration, loosening, pseudoarthrosis or recurrence of infection at a mean follow-up of 30 months. Clinical outcomes were assessed using Kirkaldy–Willis criteria, which showed 14 excellent, nine good, three fair and one poor result. Mean focal deformity improved with the use of bone graft?±?interbody cages, and the deformity correction was maintained at final follow-up. Mean pre-operative focal lordosis for the graft group was 8.5° (2–16.5°), which improved to 10.9 °(3.3–16°); mean pre-operative focal lordosis in the group treated with cages was 6.7 °(0–15°), which improved to 7°(0–15°) .

Conclusion

TLIFs with cages in patients with pyogenic lumbar spondylodiscitis allows for acceptable clearance of infection, satisfactory deformity correction with low incidence of cage migration, loosening and infection recurrence.

     

Thoracic curve correction after posterior fusion and instrumentation of structural lumbar curves in patients with adolescent idiopathic scoliosis

Introduction

Spontaneous thoracic curve correction may occur following selective anterior spinal fusion in patients with adolescent idiopathic scoliosis (AIS). However, a few reports have described outcomes in patients following selective posterior fusion. The aim of this retrospective study was to assess curve correction in AIS patients with major lumbar curves and secondary thoracic curves after selective posterior fusion of the major curve.

Methods

The records of 42 AIS patients with major lumbar and minor thoracic curves who had received selective posterior lumbar fusion with segmental pedicle screw fixation were examined. Preoperative and follow-up radiographs were examined and the following were determined: curve flexibility, Cobb angle measurements of the major and minor curves, thoracolumbar/lumbar and thoracic Cobb measurements. Also, thoracolumbar/lumbar to thoracic Cobb ratios were determined. Minimum follow-up was 2?years. Patients were compared with respect to whether final thoracic curve improvement was (group A) or was not (group B) apparent. Improvement was indicated by a final thoracic curve that was less than the preoperative thoracic curve.

Results

Thoracic curve improvement was apparent in 32 of 42 patients after surgery. The mean preoperative thoracic curve in group A was 22.5° and 15.0° at follow-up, while corresponding values in group B were 35.0° and 39.8°. There were no cases in group A and eight cases in group B in which the preoperative thoracic curve was >30°. All patients in group B had preoperative thoracic curves on lateral bending >20°. Thoracic curvature at final follow-up was strongly correlated with preoperative thoracic curvature (r?=?0.911) and thoracic curvature on lateral bending (r?=?0.948).

Conclusions

Selective posterior fusion with segmental pedicle screw fixation in patients with major lumbar AIS resulted in curve correction in the majority of cases. Preoperative thoracic curvature and thoracic curvature on lateral bending were strongly correlated with the final thoracic curvature.     

Adult spinal deformity: effectiveness of interbody lordotic cages to restore disc angle and spino-pelvic parameters through completely mini-invasive trans-psoas and hybrid approach

Purpose

The aim of the study is to assess and quantify the effectiveness of interbody lordotic cages applied by trans-psoas approach to improve radiographic parameters, showing the differences between completely mini-invasive and hybrid approach.

Methods

We collected data of 65 patients affected by degenerative lumbar deformity/diseases and underwent mini-invasive lateral interbody fusion followed by percutaneous (group A, completely mini-invasive) or open (group B, hybrid) posterior instrumentation. A subgroup underwent anterior column realignment (ACR). We assessed statistical differences in preoperative and postoperative (at least 6-month) coronal and sagittal parameters, and disc angle (DA) at each level of cage application.

Results

107 lordotic cages were implanted. Group B had the most significant mean changes, especially in coronal Cobb angle, sagittal vertical axis, lumbar lordosis (LL), pelvic incidence-LL mismatch and DA. Concerning DA, at each level of lordotic cage application, in group A changed from ?2.9° preop to ?6.5° postop (p = 0.01); in group B, DA changed from ?2.6° to ?9.5° (p = 0.002) and from +1° to ?13.2° in patients underwent ACR.

Conclusions

Minimally invasive lateral lumbar interbody fusion is an effective technique in improving sagittal parameters. When combined with posterior open approach and/or application of ACR procedure greater corrections are possible.

     

Transforaminal lumbar interbody fusion with one cage and excised local bone

Introduction

The effect of transforaminal lumbar interbody fusion (TLIF) with one cage and excised local bone were investigated in 52 patients with a mean follow-up of 18.2 months.

Method

The clinical outcomes including the modified Prolo scale and a visual analog scale (VAS), and radiological assessments including the ratio of interbody graft area, fusion rate, posterior disk height (PH), and the lordosis angle (LA) of the motion segment were studied.

Results

According to a modified Prolo scale, 90.4% of the patients obtained either excellent or good results. The VAS significantly decreased postoperatively. There was significant postoperative improvement of the PH and LA, and no significant loss of the PH and LA was found at final follow-up. The fusion rate in this series was 96.6%.

Conclusion

In conclusion, TLIF with one cage and excised local bone grafting can provide satisfactory treatment outcomes and solid interbody fusion without harvesting and grafting autologous iliac bone.     

Which posterior instrumentation is better for two-level anterior lumbar interbody fusion: translaminar facet screw or pedicle screw?

Purpose

To determine whether translaminar facet screws can provide stability equivalent to pedicle screws and whether the two posterior instrumentations have the same influence on the adjacent segments in two-level anterior lumbar interbody fusion.

Methods

In a biomechanical study conducted, we used 12 fresh human lumbar spines and tested an intact spine with a stand-alone two-level anterior lumbar interbody fusion and anterior fusion augmented with pedicle screws or translaminar facet screws, under 400 N compressive preloads and 7.5 N m moments in flexion, extension, axial rotation and lateral bending, and measured the stiffness of the operated level, range of motion and intradiscal pressure at the adjacent levels.

Results

We found a significant increase in the stiffness of the segments operated, range of motion and intradiscal pressure at the adjacent superior segment in the stand-alone two-level anterior lumbar interbody fusion during flexion, axial rotation and lateral bending, but a decrease in extension, when compared with the intact spine. The stiffness of operated segments, range of motion and intradiscal pressure in the adjacent segment are significantly higher in the two-level anterior lumbar interbody fusion augmented with posterior instrumentation than in the stand-alone two-level anterior lumbar interbody fusion. There was no significant difference between the two augmented constructs except that, at the adjacent superior segment, the intradiscal pressure was more in the construction augmented with a pedicle screw than with a translaminar facet screw in flexion.

Conclusions

Translaminar facet screws can provide stability equivalent to pedicle screws, but their influence on the adjacent segments is relatively lower; therefore, we suggest that translaminar facet screws be the choice in the optimal posterior instrumentation in a two-level anterior lumbar interbody fusion.     

Effect of lordosis angle change after lumbar/lumbosacral fusion on sacrum angular displacement: a finite element study

Purpose

To assess and characterize the sacrum angular displacements in response to lumbar lordosis after lumbar/lumbosacral fusion.

Methods

A finite element model of the lower lumbar spine-pelvis was established and used to simulate the posterior fusion at L3–L5 and L4–S1. The lordosis angle in the fusion segments was set to five different conditions with respect to the intact model: 10° less than intact, 5° less than intact, same as intact, 5° more than intact, and 10° more than intact. Variations of the sacrum angular displacements with lordosis changes were analyzed under loading setting of axial compression, flexion, extension, lateral bending, and axial rotation.

Results

Compared with the intact lordosis, both increased and decreased lumbar lordosis angles caused the sacrum angular displacements to be increased. The lordosis angle increased by 10° induced the most substantial increase in sacrum angular displacements. In addition, the sacrum angular displacements of the L4–S1 fusion model at different lordosis angles were higher than those of the L3–L5 fusion model.

Conclusion

The sacrum angular displacements occur as a result of the fusion surgery (L4–S1) and the changes in lumbar lordosis.     

Can cantilever transforaminal lumbar interbody fusion (C-TLIF) maintain segmental lordosis for degenerative spondylolisthesis on a long-term basis?

Purpose

To determine if cantilever transforaminal lumbar interbody fusion (C-TLIF) using the crescent-shaped titanium interbody spacer (IBS) favors acquisition of segmental and lumbar lordosis even for degenerative spondylolisthesis (DS) on a long-term basis.

Methods

We analyzed 23 consecutive patients who underwent C-TLIF with pedicle screw instrumentations fixed with compression for a single-level DS. Measurements on the lateral radiographs taken preoperatively, 2 weeks postoperatively and at final follow-up included disc angle (DA), segmental angle (SA), lumbar lordosis (LL), disc height (%DH) and slip rate (%slip).

Results

There was a good functional recovery with 100 % fusion rate at the mean follow-up of 62 months. Segmental lordosis (DA and SA) and  %DH initially increased, but subsequently decreased with the subsidence of the interbody spacer, resulting in a significant increase (p = 0.046) only in SA from 13.2° ± 5.5° preoperatively to 14.7° ± 6.4° at the final follow-up. Changes of LL and  %slip were more consistent without correction loss finally showing an increase of LL by 3.6° (p = 0.005) and a slip reduction by 6.7 % (p < 0.001).

Conclusions

Despite the inherent limitation of placing the IBS against the anterior endplate of the upper vertebra in the presence of DS, the C-TLIF helped significantly restore segmental as well as lumbar lordosis on a long-term basis, which would be of benefit in preventing hypolordosis-induced back pain and the adjacent level disc disease.     

Analysis of risk factors for loss of lumbar lordosis in patients who had surgical treatment with segmental instrumentation for adolescent idiopathic scoliosis

Purpose

Iatrogenic flattening of lumbar lordosis in patients with adolescent idiopathic scoliosis (AIS) was a major downside of first generation instrumentation. Current instrumentation systems allow a three-dimensional scoliosis correction, but flattening of lumbar lordosis remains a significant problem which is associated with decreased health-related quality of life. This study sought to identify risk factors for loss of lumbar lordosis in patients who had surgical correction of AIS with the use of segmental instrumentation.

Methods

Patients were included if they had surgical correction for AIS with segmental pedicle screw instrumentation Lenke type 1 or 2 and if they had a minimum follow-up of 24 months. Two groups were created, based on the average loss of lumbar lordosis. The two groups were then compared and multivariate analysis was performed to identify parameters that correlated to loss of lumbar lordosis.

Results

Four hundred and seventeen patients were analyzed for this study. The average loss of lumbar lordosis at 24 months follow-up was an increase of 10° lordosis for group 1 and a decrease of 15° for group 2. Risk factors for loss of lumbar lordosis included a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and the particular operating surgeon. The lowest instrumented vertebra or spinopelvic parameters were two of many parameters that did not seem to influence loss of lumbar lordosis.

Conclusion

This study identified important risk factors for decrease of lumbar lordosis in patients who had surgical treatment for AIS with segmental pedicle screw instrumentation, including a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and factors attributable to a particular operating surgeon that were not quantified in this study.     

Early results of stand-alone anterior lumbar interbody fusion in iatrogenic spondylolisthesis patients

Background

Iatrogenic spondylolisthesis is a challenging condition for spinal surgeons. Posterior surgery in these cases is complicated by poor anatomical landmarks, scar tissue adhesion of muscle and dural structures and difficult access to the intervertebral disc. Anterior interbody fusion provides an alternative treatment method, allowing indirect foraminal decompression, reliable disc clearance and implantation of large surface area implants.

Materials and methods

A retrospective chart review of patients with iatrogenic spondylolisthesis including pre- and post-operative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores was performed. Imaging criteria were pelvic incidence, overall lumbar lordosis and segmental lordosis. In addition, the fusion rate was investigated after 6 months.

Results

Six consecutive patients treated between 2008 and 2011 (4 female, 2 male, mean age 61 ± 7.1 years) were identified. The initially performed surgeries included decompression with or without discectomy; posterior instrumented and non-instrumented fusion. The olisthetic level was in all cases at the decompressed level. All patients were revised with stand-alone anterior interbody fusion devices at the olisthetic level filled with BMP 2. Average ODI dropped from 49 ± 11 % pre-operatively to 26.0 ± 4.0 at 24 months follow-up. VAS average dropped from 7 ± 1 to 2 ± 0. Mean total lordosis of 39.8 ± 2.8° increased to 48.5 ± 4.9° at pelvic incidences of 48.8 ± 6.8° pre-operatively. Mean segmental lordosis at L4/5 improved from 10.5 ± 6.7° to 19.0 ± 4.9° at 24 months. Mean segmental lordosis in L5/S1 increased from 15.1 ± 7.4° to 23.2 ± 5.6°. Cage subsidence due to severe osteoporosis occurred in one case after 5 months, and hence there was no further follow-up. Fusion was confirmed in all other patients.

Conclusion

Anterior interbody fusion offers good stabilisation and restoration of lordosis in iatrogenic spondylolisthesis and avoids the well-known problems associated with reentering the spinal canal for revision fusions. In this group, ODI and VAS scores were improved.     

Posterolateral versus circumferential instrumented fusion for monosegmental lumbar degenerative disc disease using an expandable cage

Background

Theoretically, 360° instrumented fusion has been considered to offer better radiological correction than PLF. Despite numerous publications, this correlation is still weak with several controversies in the relative literature.

Purpose

This prospective randomized study was designed to compare the radiological segmental results, complications and outcome of 360° instrumented fusion with the use of a single diagonal expandable PLIF device versus posterolateral pedicle screw fixation in monosegmental lumbar DDD and to show that the use of an novel expandable cage is associated with low PLIF-related complication rate compared to conventional cages reported previously.

Study design

Prospective randomized controlled clinical and radiological study.

Patient sample

Adults who suffered from monosegmental DDD were eligible for enrolment in this trial. We randomly assigned 150 patients to receive either 360° instrumented fusion (group A) with expandable cage or PLF (group B).

Outcome measures

Differences between the two groups regarding clinical parameters and radiographic sagittal measurements after 36?months of follow-up.

Methods

The record included global [T12-S1 lordosis, sagittal global spinal balance (SB) (C7-mid-femoral axis)] and segmental [segmental disc wedging (SDW), anterior (ADHr) and posterior (PDHr) disc height ratio] radiological measurements at the instrumented segment. Additionally, clinical outcome was evaluated with VAS, SF-36 (Physical function and Bodily Pain) and ODI questionnaires. Fusion was evaluated with the use of Christiansen method.

Results

In 73 and 72 participants of group A and B, respectively, who completed follow-up to 36?months, there were no differences with respect to the rate of improvement in SF-36, ODI and VAS scores. However, in the spines of group A, there was a significant increase in anterior disc height ratio (P?=?0.0057), posterior disc height (P?=?0.016) and segmental disc wedging (P?=?0.00021) without subsequent loss of correction. Fusion rate was radiologically shown in 94.5% and 87% spines of group A and B, respectively (P?>?0.2). Four and 9 spines in group A and B, respectively, showed non-union at the final observation.

Conclusions

Our findings suggest that 360° fusion offers better sagittal radiological restoration associated with circumferential fusion. However, this difference seemed not to have any medium-term clinical impact. The use of expandable cage was associated with low PLIF-related complications compared to conventional cages.     

Radiographic evaluation of indirect decompression of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion for degenerated lumbar spondylolisthesis

Purpose

Extreme lateral interbody fusion provides minimally invasive treatment of spinal deformity, but complications including nerve and psoas muscle injury have been noted. To avoid nerve injury, mini-open anterior retroperitoneal lumbar interbody fusion methods using an approach between the aorta and psoas, such as oblique lumbar interbody fusion (OLIF) have been applied. OLIF with percutaneous pedicle screws without posterior decompression can indirectly decompress the spinal canal in lumbar degenerated spondylolisthesis. In the current study, we examined the radiographic and clinical efficacy of OLIF for lumbar degenerated spondylolisthesis.

Methods

We assessed 20 patients with lumbar degenerated spondylolisthesis who underwent OLIF and percutaneous pedicle screw fixation without posterior laminectomy. MR and CT images and clinical symptoms were evaluated before and 6 months after surgery. Cross sections of the spinal canal were evaluated with MRI, and disk height, cross-sectional areas of intervertebral foramina, and degree of upper vertebral slip were evaluated with CT. Clinical symptoms including low back pain, leg pain, and lower extremity numbness were evaluated using a visual analog scale and the Oswestry Disability Index before and 6 months after surgery.

Results

After surgery, significant increases in axial and sagittal spinal canal diameter (12 and 32 %), spinal canal area (19 %), disk height (61 %), and intervertebral foramen areas (21 % on the right side, 39 % on the left), and significant decrease of upper vertebral slip (?9 %) were found (P < 0.05). Low back pain, leg pain, and lower extremity numbness were significantly reduced compared with before surgery (P < 0.05).

Conclusions

Significant improvements in disk height and spinal canal area were found after surgery. Bulging of disks was reduced through correction, and stretching the yellow ligament may have decompressed the spinal canal. Lumbar anterolateral fusion without laminectomy may be useful for lumbar spondylolisthesis with back and leg symptoms.

     

Bilateral decompression using a unilateral pedicle construct for lumbar stenosis

Purpose

To determine the effectiveness of bilateral decompression via a unilateral approach using unilateral pedicle screw fixation for two-level lumbar stenosis with instability.

Methods

Between October 2006 and October 2010, 98 patients (61 men and 37 women) who had reached the three-year follow-up interval were treated with unilateral pedicle screw fixation at the authors’ institution. All patients underwent two-level transforaminal lumbar interbody fusion (TLIF), and the mean age was 59.6 years (range, 40–72). Visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were used to assess the pre-operative and postoperative clinical results. Fusion status, the disc space height, and the whole lumbar lordotic angle were analysed for the radiological evaluation.

Results

The ODI scores decreased significantly in both early and late follow-up evaluations and the visual analog scale (VAS) score demonstrated significant improvement in late follow-up (P < 0.01). The disc space height (P < 0.05) and the whole lumbar lordotic angle (P < 0.05) were increased at the final follow-up. Successful fusion was achieved in all patients.

Conclusion

Bilateral decompression via a unilateral approach using unilateral pedicle screw fixation for two-level lumbar stenosis with instability, which can maintain the lumbar lordosis and the disc space height, is an effective and less invasive method than with bilateral constructs.     

Fusion techniques for adult isthmic spondylolisthesis: a systematic review

Introduction

Various fusion techniques have been used to treat lumbar spine isthmic spondylolisthesis (IS) in adults, including anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), posterolateral fusion (PLF), and circumferential fusion. The objective of this study was to evaluate which fusion technique provides the best clinical and radiological outcome for adult lumbar IS.

Materials and methods

A systematic review was performed. MEDLINE databases and reference lists of selected articles were searched. Inclusion criteria stated that the studies had to be controlled and that they compared clinical and radiological outcomes of various fusion techniques for treating adult IS. Exclusion criteria were use of only one treatment and non-English language articles. Two reviewers independently extracted relevant data from each included study. Statistical comparisons were made when appropriate.

Results

Nine studies that compared two surgical approaches to IS were included in this systematic review. Three were prospective studies, and six were retrospective studies. Two studies compared ALIF with instrumented PLF and ALIF with percutaneous pedicle screw fixation, two studies compared ALIF and TLIF, and five studies compared PLIF and PLF. ALIF was superior to other techniques regarding restoration of disc height, segmental lordosis, and whole lumbar lordosis. TLIF had lower complication rates. ALIF combined with PLF showed lower nonfusion rates than other techniques. However, there were no significant differences in clinical outcomes between any two techniques.

Conclusion

Compared to other fusion techniques, TLIF shows fewer complications, ALIF shows better sagittal alignment, and circumferential fusion showed better fusion rates. It was difficult to make recommendations about the optimal approach because of the methodological variance in the publications.     

Minimally invasive transforaminal lumber interbody fusion and degenerative lumbar spine disease

Objective

The purpose of this study was to assess the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) surgery for degenerative lumbar spine disease.

Methods

A prospective analysis of 34 consecutive patients who underwent a MI-TLIF using image guidance between July 2008 and November 2010. The patient group comprised 19 males and 15 females (mean age 56), 23 of whom had undergone additional reduction of spondylolisthesis. All patients underwent post-operative CT imaging to assess pedicle screw, cage placement and fusion at 6 months. Oswestry Disability Index (ODI) scores were recorded pre-operatively and at 6-month follow up.

Results

33/34 (97.1 %) patients showed evidence of fusion at 6 months with a mean improvement of 27 on ODI scores. The mean length of hospital stay was 4 days. The mean operative time was 173 min.

Complications observed

1/34 (2.9 %) suffered a pulmonary embolism and 1/34 (2.9 %) patients developed transient nerve root pain post-operatively. There were no occurrences of infection and no post-operative CSF leaks.

Conclusion

MI-TLIF offers patients a safe and effective surgical treatment option to treat degenerative lumbar spine disease.     

Surgical management by one-stage posterior transforaminal lumbar debridement, interbody fusion, and posterior instrumentation for lumbo-sacral tuberculosis in the aged

Purpose

To evaluate the clinical study efficacy and feasibility of 17 aged patients with lumbo-sacral tuberculosis treated by one-stage posterior transforaminal lumbar debridement, interbody fusion, and posterior instrumentation.

Methods

17 aged patients who suffered from lumbo-sacral tuberculosis were admitted into our hospital between March 2003 and October 2010. All of them were treated by one-stage posterior transforaminal lumbar debridement, interbody fusion, and posterior instrumentation. Then the clinical efficacy with statistical analysis was evaluated based on the materials on the lumbo-sacral angle, neurological status that was recorded by Frankel grade system, and erythrocyte sedimentation rate (ESR), which were collected at certain time.

Results

The average follow-up period was 47.5?±?17.1?months (17?C71?months), In the 17 cases, no postoperative complications related to instrumentation occurred and neurologic function was improved in various degrees. The mean preoperative lumbo-sacral angle was 20.5°?±?1.7° (range 18.0°?C23.0°). The lumbo-sacral angle became 29.1°?±?1.5° (range 26.4°?C31.0°) postoperatively. The average pretreatment ESR was 57.4?±?16.8?mm/h (33?C95?mm/h), which got normal (9.2?±?3.1?mm/h) within 3?months in all patients. All patients got bony fusion within 6?C8?months after surgery.

Conclusions

One-stage posterior transforaminal lumbar debridement, interbody fusion, and posterior instrumentation can be an effective treatment method for the treatment of lumbo-sacral tuberculosis in the aged patients.     

Comparison of fusion rates following transforaminal lumbar interbody fusion using polyetheretherketone cages or titanium cages with transpedicular instrumentation

Purpose

Compared to titanium cage, polyetheretherketone (PEEK) cage with pedicle screw fixation has been increasingly used in transforaminal lumbar interbody fusion (TLIF). However, there is insufficient evidence supporting the superiority of PEEK cages over titanium cages as optimal TLIF spacers. The aim of this study was to compare the clinical and radiographic outcomes of patients at a 2-year follow-up after undergoing instrumented TLIF in which either a PEEK cage or a titanium cage was implanted.

Materials and methods

We retrospectively analyzed prospectively collected 48 patients who underwent single-level TLIF in which the first 23 patients received a titanium cage and the 25 patients received a PEEK cage. Patient demographics, clinical outcomes, and radiographic imaging were studied.

Results

Improvement of clinical outcomes was comparable between the two groups. Based on the criteria using computed tomography, 96 % in the Titanium group and 64 % in the PEEK group showed fusion at 12 months. At 24 months, fusion rate in the Titanium group was increased to 100 %, while PEEK group showed 76 % of fusion rate. In the PEEK group, vertebral osteolysis was noted in 60 % of the cases with nonunion. This abnormal finding was not observed in the Titanium group. Vertebral osteolysis was significantly associated with nonunion.

Conclusions

The superiority of PEEK cages over titanium cages for bony fusion was not demonstrated. Additionally, we found unfavorable radiographic findings in the cases with a PEEK cage, which may lead to nonunion. Improvement in biocompatibility of a PEEK cage will be needed to increase the fusion rate.     

Influence of transforaminal lumbar interbody fusion procedures on spinal and pelvic parameters of sagittal balance

Introduction

Restitution of sagittal balance is important after lumbar fusion, because it improves fusion rate and may reduce the rate of adjacent segment disease. The purpose of the present study was to describe the impact of transforaminal lumbar interbody fusion (TLIF) procedures on pelvic and spinal parameters and sagittal balance.

Materials and methods

Forty-five patients who had single-level TLIF were included in this study. Pelvic and spinal radiological parameters of sagittal balance were measured preoperatively, postoperatively and at latest follow-up.

Results

Age at surgery averaged 58.4 (±9.6) years. Mean follow-up was 35.1 months (±4.1). Twenty-nine percent of the patients exhibited anterior imbalance preoperatively, with high pelvic tilt (17.6° ± 7.9°). Of the 32 (71%) patients well balanced before the procedure, 22 (70%) had a large pelvic tilt (>20°), due to retroversion of the pelvis as an adaptive response to the loss of lordosis. Three dural tears (7%) were reported intraoperatively. Interbody cages were more posterior than intended in 27% of the cases. Disc height and lumbar lordosis at fusion level significantly increased postoperatively (p < 0.05 and p < 0.001). Pelvic tilt was significantly reduced (p < 0.01) postoperatively, whereas the global sagittal balance was not significantly modified (p = 0.07).

Conclusion

Single-level circumferential fusion helps patients reducing their pelvic compensation, but the amount of correction does not allow for complete correction of sagittal imbalance.     

Vertebral Bodies or Discs: Which Contributes More to Human-like Lumbar Lordosis?

Background

The attainment of upright posture, with its requisite lumbar lordosis, was a major turning point in human evolution. Nonhuman primates have small lordosis angles, whereas the human spine exhibits distinct lumbar lordosis (30°–80°). We assume the lumbar spine of the pronograde ancestors of modern humans was like those of extant nonhuman primates, but which spinal components changed in the transition from small lordosis angles to large ones is not fully understood.

Questions/Purposes

We wished to determine the relative contribution of vertebral bodies and intervertebral discs to lordosis angles in extant primates and humans.

Methods

We measured the lordosis, intervertebral disc, and vertebral body angles of 100 modern humans (orthograde primates) and 56 macaques (pronograde primates) on lateral radiographs of the lumbar spine (humans–standing, macaques–side-lying).

Results

The humans exhibited larger lordosis angles (51°) and vertebral body wedging (5°) than did the macaques (15° and ?25°, respectively). The differences in wedging of the intervertebral discs, however, were much less pronounced (46° versus 40°).

Conclusions

These observations suggest the transition from pronograde to orthograde posture (ie, the lordosis angle) resulted mainly from an increase in vertebral body wedging and only in small part from the increase in wedging of the intervertebral discs.     

Corner osteotomy: a modified pedicle subtraction osteotomy for increased sagittal correction in the lumbar spine

Introduction

Sagittal imbalance is a spine deformity with multifactorial etiology, associated with severe low back pain and gait disturbance that worsen deeply patients’ quality of life. The amount of correction achievable through PSO is limited by the height of the resection of the posterior wall, causing a ceiling of segmental correction of 30–35°. The aim of this study is to describe and preliminarily evaluate the results of an alternative technique, corner osteotomy (CO), that can increase the amount of correction.

Materials and methods

From March 2012, every patient examined in our Division, diagnosed with sagittal imbalance to be treated with PSO, underwent CO and fusion. This technique consists in removing the posterior vertebral arch, the pedicle and the posterior–superior corner of the vertebral body; the inferior endplate of the vertebra above is prepared and the superior adjacent disc removed to obtain, when closing the osteotomy, a direct interbody fusion. Ten patients undergoing CO were compared with 20 patients undergoing PSO regarding spinopelvic parameters, operative variables, complications and degree of correction.

Results

Patients undergoing CO obtained higher lordotic angle at the osteotomy than patients undergoing PSO (36.6° ± 8.2° vs 16.5° ± 9.5°, p < 0.001) and had lower postoperative PT and SVA and higher average increase in lordosis. Complications were similar between groups. A trend toward longer surgical time, greater bleeding and higher transfusion rate was observed in the CO group, though this finding could be related to higher complexity of cases or incidence of associated anterior approach.

Discussion and conclusions

Corner osteotomy technique was more effective than the PSO in increasing segmental and lumbar lordosis with modest increase in blood loss and similar complication rate. The CO technique, in addition, proved a good reproducibility. Further studies with larger populations should confirm these preliminary results.

     

Tranexamic acid reduces postoperative blood loss of degenerative lumbar instability with stenosis in posterior approach lumbar surgery: a randomized controlled trial

Study design

This study is randomized controlled trial.

Purpose

To evaluate the effect of tranexamic acid (TXA) on reducing postoperative blood loss in posterior approach lumbar surgery for degenerative lumbar instability with stenosis.

Methods

Sixty patients with degenerative lumbar instability with stenosis were randomized into TXA and control groups, receiving 15 mg/kg body weight of TXA or placebo (0.9 % Sodium chloride solution) intravenously, respectively, before the skin incision was made. The operation of pedicle screw system fixation was performed for all patients, and then selective laminectomy and posterior lumbar interbody fusion (PLIF) were carried out. Intraoperative and postoperative blood loss were compared between the two groups. And the complication of TXA was also investigated.

Results

There were no statistically significant differences between the TXA and control groups in terms of age, sex, body mass index, and operation time. There was no significantly difference in intraoperative blood loss between the two groups. However, in the TXA group, postoperative blood loss was significantly lower than that in the control group (13.0 %). Especially, postoperative blood loss during the first 12 h was reduced by 29.9 % as compared to the control group. There were no thromboembolic events or other complications occurred in either group.

Conclusions

Preoperative single-dose TXA can significantly reduce postoperative blood loss in posterior approach lumbar surgery, and there were no significant side effects.