Lumbar Interbody Fusion for Adjacent Segment Disease: An illustrative Case of The Transforaminal Approach (MIS-TLIF)

The scope of minimally invasive surgical (MIS) strategies for management of spinal pathology continues to expand. MIS transforaminal lumbar interbody fusion (TLIF) is an attractive alternative for the management of adjacent level disease. It minimizes approach related morbidities and provides anterior column support at a location where all 3 columns are affected by the adjacent segment degeneration (ASD).Our surgical technique involves the cannulation of the pedicles with K-wires. This is followed by a facetectomy and foraminal decompression with subsequent discectomy and endplate preparation. The cage is inserted followed by pedicle screw placement. To illustrate this technique, we present to you a case of a 56-year-old Female with previous L2–S1 successful arthrodesis, treated with MIS TLIF of L1–L2 for new adjacent segment disc herniation.This chapter describes the effective use of MIS TLIF in the treatment of adjacent segment disease and offers a unique strategy in management of this problem.     

Biomechanical comparison of anterior lumbar interbody fusion and transforaminal lumbar interbody fusion

STUDY DESIGN: An in vitro biomechanical comparison of 2 fusion techniques, anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF), on cadaveric human spines. OBJECTIVE: To compare the immediate construct stability, in terms of range of motion (ROM) and neutral zone, of ALIF, including 2 separate approaches, and TLIF procedures with posterior titanium rod fixation. SUMMARY OF BACKGROUND DATA: Both ALIF and TLIF have been used to treat chronic low back pain and instability. In many cases, the choice between these 2 techniques is based only on personal preference. No biomechanical performance comparison between these 2 fusion techniques is available to assist surgical decision. METHODS: Twelve cadaveric lumbar motion segments were loaded sinusoidally at 0.05 Hz and 5 Nm in unconstrained axial rotation, lateral bending and flexion extension. Specimens were randomly divided into 2 groups with 6 in each group. One group was assigned for TLIF whereas the other group for ALIF. In the ALIF group, there were 3 steps. First, the lateral ALIF procedure with the anterior longitudinal ligament (ALL) intact was performed. Afterwards, the ALL was cut without removing the ALIF cage. Finally, another appropriately sized ALIF cage was inserted anteriorly. Biomechanical tests were conducted after each step. RESULTS: In the ALIF group, the lateral ALIF and subsequent anterior ALIF reduced segmental motion significantly (P=0.03) under all loading conditions. Removing the ALL increased ROM by 59% and 142% in axial rotation and flexion extension, respectively (P=0.03). The anterior ALIF approach was able to achieve similar biomechanical stability of the lateral approach in lateral bending and flexion extension (P>0.05) under all loading conditions. The TLIF procedure significantly reduced the range of motion compared with the intact state (P=0.03). However, no statistical difference was detected between the TLIF group and the ALIF group (P>0.05). CONCLUSIONS: Both ALIF and TLIF procedures combined with posterior instrumentation significantly improved construct stability of intact spinal motion segments. However, there was no statistical difference between these 2 fusion techniques. The 2 ALIF approaches (lateral and anterior) also had similar construct stability even though anterior longitudinal ligament severing significantly reduced stability.     

Clinical and radiological outcome of anterior–posterior fusion versus transforaminal lumbar interbody fusion for symptomatic disc degeneration: a retrospective comparative study of 133 patients

Abundant data are available for direct anterior/posterior spine fusion (APF) and some for transforaminal lumbar interbody fusion (TLIF), but only few studies from one institution compares the two techniques. One-hundred and thirty-three patients were retrospectively analyzed, 68 having APF and 65 having TLIF. All patients had symptomatic disc degeneration of the lumbar spine. Only those with one or two-level surgeries were included. Clinical chart and radiologic reviews were done, fusion solidity assessed, and functional outcomes determined by pre- and postoperative SF-36 and postoperative Oswestry Disability Index (ODI), and a satisfaction questionnaire. The minimum follow-up was 24 months. The mean operating room time and hospital length of stay were less in the TLIF group. The blood loss was slightly less in the TLIF group (409 vs. 480 cc.). Intra-operative complications were higher in the APF group, mostly due to vein lacerations in the anterior retroperitoneal approach. Postoperative complications were higher in the TLIF group due to graft material extruding against the nerve root or wound drainage. The pseudarthrosis rate was statistically equal (APF 17.6% and TLIF 23.1%) and was higher than most published reports. Significant improvements were noted in both groups for the SF-36 questionnaires. The mean ODI scores at follow-up were 33.5 for the APF and 39.5 for the TLIF group. The patient satisfaction rate was equal for the two groups. This work is dedicated to the memory of Grace and Julia Hanson.     

Posterior lumbar interbody fusion

Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) create intervertebral fusion by means of a posterior approach. Both techniques are useful in managing degenerative disk disease, severe instability, spondylolisthesis, deformity, and pseudarthrosis. Successful results have been reported with allograft, various cages (for interbody support), autograft, and recombinant human bone morphogenetic protein-2. Interbody fusion techniques may facilitate reduction and enhance fusion. The rationale for PLIF and TLIF is biomechanically sound. However, clinical outcomes of different anterior and posterior spinal fusion techniques tend to be similar. PLIF has a high complication rate (dural tear, 5.4% to 10%; neurologic injury, 9% to 16%). These findings, coupled with the versatility of TLIF throughout the entire lumbar spine, may make TLIF the ideal choice for an all-posterior interbody fusion.     

Transforaminal interbody fusion versus anterior-posterior interbody fusion of the lumbar spine: a financial analysis

Lumbar interbody fusion can be performed anteriorly or posteriorly. An anterior approach generally requires an access surgeon and often is combined with a posterior fusion. A traditional posterior interbody fusion can destabilize the spinal motion segment and requires neural retraction. A new surgical technique, a transforaminal lumbar interbody fusion (TLIF), was recently described. It requires minimal neural retraction, and the disk space is exposed posterolaterally with removal of only one facet joint. This study compares the cost of an anterior-posterior one-level lumbar fusion with the cost of the same procedure performed using the TLIF technique. Table 1 lists the specific demographics. A retrospective review of the hospital charges of 80 patients undergoing interbody lumbar stabilization was conducted. The two groups consisted of 40 patients with an anterior-posterior fusion and 40 patients who were fused circumferentially using the TLIF technique. A cost analysis with normalization of 1998 dollars between the two groups was performed. The TLIF group had an average operative time of 213 minutes, compared with 269 minutes for the anterior-posterior group. In addition, an average additional 38 minutes were required to turn the patient from the anterior or posterior position. The average blood loss for the anterior-posterior procedure was 969 mL, compared with 489 mL for the TLIF group. Twenty-three of the anterior-posterior patients received an average of 2.2 units of blood and six of the TLIF patients received an average of 1.3 units. Use of the surgical intensive care unit was much lower in the TLIF group (38 of 40 patients versus 2 of 40 patients). The average length of stay was 6.1 days for the anterior-posterior group compared with an average of 3.3 days for the TLIF group. The average cost of the anterior-posterior patients was $49,085, compared with $33,784 for the TLIF group. Cost analysis between the two groups show the TLIF patients had an average savings of approximately $15,000 per admission. This cost comparison was conducted only for the time of the operative procedure. No attempt was made to analyze rates of fusion between the two groups or ultimate clinic outcome. There were no major complications in either group, and no patient returned to surgery for a lumbar spinal problem at the authors' hospital within 1 year of the index procedure.     

Evaluation of an injectable calcium phosphate cement as an autograft substitute for transpedicular lumbar interbody fusion: a controlled,prospective study in the sheep model

Anteroposterior procedures for lumbar interbody fusion usually combine posterior instrumentation with anterior techniques that achieve primary stability for compressive loading: tricortical strut-graft, anterior plating systems, or cages. In comparison to transpedicular lumbar interbody fusion (TLIF), these methods bear the burden of the additional anterior approach. TLIF with autograft, in contrast, does not prove to be clinically sufficient because of its lack of primary compressive stability. In a sheep model, we therefore developed a TLIF method providing primary stability for axial loading. In 24 sheep, L4-L6 were instrumented posteriorly. An endoscopically assisted L4/L5 TLIF procedure was performed via a bilateral approach. In 12 sheep, the defect was filled with an injectable calcium phosphate cement. After setting, this cement gains a stability against axial loading comparable to healthy vertebrae. Another 12 sheep were treated with autograft. The animals were killed at 8 weeks and evaluated by radiologic (plain X-ray, computed tomography), histologic and histomorphometric analysis, and fluorochrome labeling. Only ten autograft sheep were available for evaluation. Radiologically and histologically, TLIF with calcium phosphate led to a 2/12 fusion rate compared to autograft (1/10 fused) (P=0.70). Semiquantitative radiologic and histologic scoring did not reveal significant differences (P=0.88). In 4/12 calcium phosphate sheep, excessive resorption was responsible for local aseptic inflammation. The findings of this study show that calcium phosphate cement is not superior to autograft, despite enabling primary stability against compressive loading. Biointegration of the osteoconductive cement does not occur fast enough, and shear forces cause early cement fracture, subsequent fragmentation, and gross resorption with the possibility of severe inflammation.     

The “TFP” Fusion Technique for Posterior 360° Lumbar Fusion: a Combination of Open Decompression,Transforaminal Lumbar Interbody Fusion,and Facet Fusion with Percutaneous Pedicle Screw Fixation

Because degenerative spondylolithesis is prevalent in the elderly with associated osteoporosis, the rate of failure of pedicle screws is high; this leads to pseudoarthrosis and potentially requires reoperation. The burden of recurrent symptoms and reoperation is sufficiently significant to warrant prevention. We here describe a hybrid technique that involves a combination of a unilateral approach to bilateral decompression via a midline incision, transforaminal lumbar interbody fusion (TLIF), contralateral facet fusion, and percutaneously placed pedicle screws without compromising operative time and visualization. This approach is familiar to spine surgeons, adheres to the basic principles of minimally invasive spine surgery technique, minimizes dural and neural injury because of the unilateral TLIF approach, and provides a superior fusion construct because of facet fusion. In this procedure, patients with degenerative spondylolisthesis or scoliosis with moderate‐severe canal/foraminal stenosis undergo a midline unilateral TLIF and contralateral facet fusion with closure of the midline incision. Percutaneous pedicle screws are inserted under stereotactic guidance with reduction of the deformity using a pedicle screws construct. Rods are inserted percutaneously to link the pedicle screws. Image intensification is used to confirmed satisfactory screw placement and reduction of the spondylolisthesis.     

Combined posteroanterior fusion versus transforaminal lumbar interbody fusion (TLIF) in thoracolumbar burst fractures

BackgroundThe optimal treatment strategy for burst fractures of the thoracolumbar junction is discussed controversially in the literature. Whilst 360° fusion has shown to result in better radiological outcome, recent studies have failed to show its superiority concerning clinical outcome. The morbidity associated with the additional anterior approach may account for these findings. The aim of this prospective observational study was therefore to compare two different techniques for 360° fusion in thoracolumbar burst fractures using either thoracoscopy or a transforaminal approach (transforaminal lumbar interbody fusion (TLIF)) to support the anterior column.MethodsPosterior reduction and short-segmental fixation using angular stable pedicle screw systems were performed in all patients as a first step. Monocortical strut grafts were used for the anterior support in the TLIF group, whilst tricortical grafts or titanium vertebral body replacing implants of adjustable height were used in the combined posteroanterior group. At final follow-up, the radiological outcome was assessed by performing X-rays in a standing position. The clinical outcome was measured using five validated outcome scores. The morbidity associated with the approaches and the donor site was assessed as well.ResultsThere were 21 patients in the TLIF group and 14 patients in the posteroanterior group included. The postoperative loss of correction was higher in the TLIF group (4.9° ± 8.3° versus 3.4° ± 6.4°, p > 0.05). There were no significant differences regarding the outcome scores between the two groups. There were no differences in terms of return to employment, leisure activities and back function either. More patients suffered from donor-site morbidity in the TLIF group, whilst the morbidity associated with the surgical approach was higher in the posteroanterior group.ConclusionThe smaller donor-site morbidity in the posteroanterior group is counterbalanced by an additional morbidity associated with the anterior approach resulting in similar clinical outcome. Mastering both techniques will allow the spine surgeon to be more flexible in specific situations, for example, in patients with neurological deficits or severe concomitant thoracic trauma.     

Transforaminal lumbar interbody fusion: surgical technique and results in 24 patients

OBJECTIVE: The advantage of anterior column support and fusion in addition to pedicle fixation in patients with degenerative spinal disorders has become increasingly clear. With the increase in popularity of this treatment, a variety of techniques have been used to achieve the goal of anterior column support, fusion, and segmental instrumentation. Posterior lumbar interbody fusion has been used since the late 1940s in the treatment of degenerative lumbar spine. We evaluated a modification to posterior lumbar interbody fusion called transforaminal lumbar interbody fusion (TLIF). METHODS: A retrospective analysis was performed on 24 patients (9 women, 15 men) who underwent TLIF. The approach involved a unilateral laminectomy and inferior facetectomy at the level of fusion. The interbody fusion was achieved from this unilateral approach by performing discectomy, arthrodesis, and insertion of one or two titanium cages packed with autologous bone. The average age of the patients in this study was 42.6 +/- 12.5 years. Five patients were smokers. Five cases were related to workmen's compensation. Seventeen patients' original symptoms were a combination of low back pain and radiculopathy. Ten patients had had a previous spine operation. RESULTS: Eleven patients had L4-S1 TLIFs. The rest of the patients had a single-level TLIF (L2-S1). Average intensive care unit and floor days were 1.1 +/- 1.0 and 5.8 +/- 2.2 days, respectively. The number of days to ambulation was 2.8 +/- 1.6 days. There were a total of six self-limited complications in 24 patients (including one transient neurological complication). The average follow-up time was 16.9 +/- 9.1 months. Twenty-two patients had solid fusions. A modified Prolo scale (4 worst, 20 best) was used to evaluate the clinical outcome. The average score was 16.1 +/- 4.1. CONCLUSION: TLIF is a reliable and safe technique for interbody support that can be performed with excellent clinical outcome. In the authors' experience, TLIF offers excellent exposure with minimal risk. This applies particularly in cases of repeat spine surgery, in which the presence of scar tissue makes traditional posterior lumbar interbody fusion techniques difficult or impossible. In addition, TLIF seems to be a viable alternative to anteroposterior circumferential fusion and/or anterior lumbar interbody fusion.     

经椎间孔椎体间植骨治疗下腰椎爆裂性骨折

目的 探讨在下腰椎爆裂性骨折中应用单一后路经椎间孔椎体间植骨融合术重建椎体前中柱的有效性.方法 2009年1月～2011 年6月,采用单一后路切开复位椎弓根内固定经椎间孔椎体间植骨融合术治疗下腰椎爆裂性骨折19例.分别评价术前、术后、末次随访时的影像学指标变化,及术前与术后末次随访时神经功能变化.结果 19例患者平均随访15.6 个月.所有患者术后未发生切口感染、神经功能损伤及内固定器松动断裂等并发症.末次随访时18例患者证实椎间融合,19例患者术前平均伤椎高度为正常椎体高度的（40.62±12.32）%,术后恢复至（96.52±10.62）%,末次随访时为（95.43%9.54）%.腰椎前凸角术前32.2°±5.1°,术后38.4°±5.2°,末次随访时为38.4°±7.2°.末次随访时伴有神经功能障碍的患者均有1级以上的恢复.结论 下腰椎爆裂性骨折行后路椎弓根螺钉内固定经椎间孔椎体间植骨融合术,能完成短节段三柱固定,同时修复了前柱及矫正脊柱后凸,取得满意的骨性融合率.     

Transforaminal lumbar interbody fusion: a safe technique with satisfactory three to five year results

The unilateral transforaminal approach for lumbar interbody fusion as an alternative to the anterior (ALIF) and traditional posterior lumbar interbody fusion (PLIF) combined with pedicle screw instrumentation is gaining in popularity. At present, a prospective study using a standardized tool for outcome measurement after the transforaminal lumber interbody fusion (TLIF) with a follow-up of at least 3 years is not available in the current literature, although there have been reports on specific complications and cost efficiency. Therefore, a study of TLIF was undertaken. Fifty-two consecutive patients with a minimum follow-up of 3 years were included, with the mean follow-up being 46 months (36–64). The indications were 22 isthmic spondylolistheses and 30 degenerative disorders of the lumbar spine. Thirty-nine cases were one-level, 11 cases were two-level, and two cases were three-level fusions. The pain and disability status was prospectively evaluated by the Oswestry disability index (ODI) and a visual analog scale (VAS). The status of bony fusion was evaluated by an independent radiologist using anterior–posterior and lateral radiographs. The operation time averaged 173 min for one-level and 238 min for multiple-level fusions. Average blood loss was 485 ml for one-level and 560 ml for multiple-level fusions. There were four serious complications registered: a deep infection, a persistent radiculopathy, a symptomatic contralateral disc herniation and a pseudarthrosis with loosening of the implants. Overall, the pain relief in the VAS and the reduction of the ODI was significant (P<0.05) at follow-up. The fusion rate was 89%. At the latest follow-up, significant differences of the ODI were neither found between isthmic spondylolistheses and degenerative diseases, nor between one- and multiple-level fusions. In conclusion, the TLIF technique has comparable results to other interbody fusions, such as the PLIF and ALIF techniques. The potential advantages of the TLIF technique include avoidance of the anterior approach and reduction of the approach related posterior trauma to the spinal canal.     

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.     

Transforaminale lumbale interkorporelle Fusion zur Versorgung der degenerativen Spondylolisthese

Introduction

Degenerative spondylolisthesis (DS) is a common cause of lumbal and lumbosacral pain as well as radicular pain. Retention and fusion is a good treatment option. Some patients have a symptomatic adjacent degenerative disc disease (DDD) in addition to DS. In these cases the adjacent segments should be fused as well. There are different techniques of fusion available, such as posterior with instrumentation or additional anterior support. This study evaluated results of transforaminal lumbar interbody fusion (TLIF) in patients with monosegmental DS and adjacent DDD.

Material and methods

A total of 28?patients with monosegmental DS and adjacent DDD were included into the study (all patients with bisegmental posterior instrumentation and fusion, 14?patients 1 level TLIF, 14?patients 2 level TLIF). Before surgery and 12?months after surgery the following measurements were made: pain (visual analog scale VAS), Oswestry disability index (ODI) and plain radiographs with radiometric analysis. In a sub-analysis patients with 1 and 2 level TLIF were compared.

Results

Pain reduction (average VAS from 8.7?C3.1) and ODI (63% to 28%) showed significant improvements. Radiometric analysis showed a significant disc height reconstruction and a significant reduction of spondylolisthesis (TLIF level with spondylolisthesis). Bisegmental anterior support showed a significantly better relordosation compared to monosegmental anterior support. The complication rate was 21.4% including hemorrhages, dura leakage, wound infection and adjacent segment degeneration. There were no fatal complications.

Discussion

The TLIF procedure is a safe and effective treatment for monosegmental DS with adjacent symptomatic DDD. Clinical results (pain, function) show no difference between both kinds of fusion (dorsal fusion and instrumentation versus dorsal fusion with instrumentation and TLIF) for the adjacent DDD. However, additional anterior support is more effective for relordosation of the segment. This could have impact on the mid-term and long-term outcome or in cases of adjacent segment fusion.     

Comparison of complications,costs, and length of stay of three different lumbar interbody fusion techniques: an analysis of the Nationwide Inpatient Sample database

Background contextLumbar interbody fusion (LIF) techniques have been used for years to treat a number of pathologies of the lower back. These procedures may use an anterior, posterior, or combined surgical approach. Each approach is associated with a unique set of complications, but the exact prevalence of complications associated with each approach remains unclear.PurposeTo investigate the rates of perioperative complications of anterior lumbar interbody fusion (ALIF), posterior/transforaminal lumbar interbody fusion (P/TLIF), and LIF with a combined anterior-posterior interbody fusion (APF).Study design/settingRetrospective review of national data from a large administrative database.Patient samplePatients undergoing ALIF, P/TLIF, or APF.Outcome measuresPerioperative complications, length of stay (LOS), total costs, and mortality.MethodsThe Nationwide Inpatient Sample database was queried for patients undergoing ALIF, P/TLIF, or APF between 2001 and 2010 as identified via International Classification of Diseases, ninth revision codes. Univariate analyses were carried out comparing the three cohorts in terms of the outcomes of interest. Multivariate analysis for primary outcomes was carried out adjusting for overall comorbidity burden, race, gender, age, and length of fusion. National estimates of annual total number of procedures were calculated based on the provided discharge weights. Geographic distribution of the three cohorts was also investigated.ResultsAn estimated total of 923,038 LIFs were performed between 2001 and 2010 in the United States. Posterior/transforaminal lumbar interbody fusions accounted for 79% to 86% of total LIFs between 2001 and 2010, ALIFs for 10% to 15%, and APF decreased from 10% in 2002 to less than 1% in 2010. On average, P/TLIF patients were oldest (54.55 years), followed by combined approach (47.23 years) and ALIF (46.94 years) patients (p<.0001). Anterior lumbar interbody fusion, P/TLIF, and combined surgical costs were $75,872, $65,894, and $92,249, respectively (p<.0001). Patients in the P/TLIF cohort had the greatest number of comorbidities, having the highest prevalence for 10 of 17 comorbidities investigated. Anterior-posterior interbody fusion group was associated with the greatest number of complications, having the highest incidence of 12 of the 16 complications investigated.ConclusionsThese data help to define the perioperative risks for several LIF approaches. Comparison of outcomes showed that a combined approach is more expensive and associated with greater LOS, whereas ALIF is associated with the highest postoperative mortality. These trends should be taken into consideration during surgical planning to improve clinical outcomes.     

Biomechanical comparison of unilateral and bilateral pedicle screws fixation for transforaminal lumbar interbody fusion after decompressive surgery -- a finite element analysis

ABSTRACT: BACKGROUND: Little is known about the biomechanical effectiveness of transforaminal lumbar interbody fusion (TLIF) cages in different positioning and various posterior implants used after decompressive surgery. The use of the various implants will induce the kinematic and mechanical changes in range of motion (ROM) and stresses at the surgical and adjacent segments. Unilateral pedicle screw with or without supplementary facet screw fixation in the minimally invasive TLIF procedure has not been ascertained to provide adequate stability without the need to expose on the contralateral side. This study used finite element (FE) models to investigate biomechanical differences in ROM and stress on the neighboring structures after TLIF cages insertion in conjunction with posterior fixation. METHODS: A validated finite-element (FE) model of L1-S1 was established to implant three types of cages (TLIF with a single moon-shaped cage in the anterior or middle portion of vertebral bodies, and TLIF with a left diagonally placed ogival-shaped cage) from the left L4-5 level after unilateral decompressive surgery. Further, the effects of unilateral versus bilateral pedicle screw fixation (UPSF vs. BPSF) in each TLIF cage model was compared to analyze parameters, including stresses and ROM on the neighboring annulus, cage-vertebral interface and pedicle screws. RESULTS: All the TLIF cages positioned with BPSF showed similar ROM (<5 %) at surgical and adjacent levels, except TLIF with an anterior cage in flexion (61 % lower) and TLIF with a left diagonal cage in left lateral bending (33 % lower) at surgical level. On the other hand, the TLIF cage models with left UPSF showed varying changes of ROM and annulus stress in extension, right lateral bending and right axial rotation at surgical level. In particular, the TLIF model with a diagonal cage, UPSF, and contralateral facet screw fixation stabilize segmental motion of the surgical level mostly in extension and contralaterally axial rotation. Prominent stress shielded to the contralateral annulus, cage-vertebral interface, and pedicle screw at surgical level. A supplementary facet screw fixation shared stresses around the neighboring tissues and revealed similar ROM and stress patterns to those models with BPSF. CONCLUSIONS: TLIF surgery is not favored for asymmetrical positioning of a diagonal cage and UPSF used in contralateral axial rotation or lateral bending. Supplementation of a contralateral facet screw is recommended for the TLIF construct.     

Radiographic analysis of transforaminal lumbar interbody fusion for the treatment of adult isthmic spondylolisthesis

The radiographs of 35 consecutive adult patients with isthmic spondylolisthesis who underwent a transforaminal lumbar interbody fusion (TLIF) with one or two Brantigan carbon fiber cages and pedicle screw instrumentation were evaluated. Anterolisthesis, disk space height, and slip angle were measured in preoperative and postoperative standing neutral radiographs. Anterolisthesis was reduced and disk space height was increased with the TLIF procedure. Average slip angle, however, was not significantly altered. The restoration of lordosis across the listhetic disk space correlated with a more anterior placement of the interbody cage within the disk space. The TLIF technique, performed with the Brantigan cage and pedicle screw instrumentation, appears to be able to restore disk height and reduce forward translation in patients with isthmic spondylolisthesis, but improvement in sagittal alignment is dependent upon anterior placement of the interbody device.     

One-stage posterior debridement, transforaminal lumbar interbody fusion and instrumentation in treatment of lumbar spinal tuberculosis: a retrospective case series

Purpose

The purpose of this study is to compare the clinical outcomes of surgical management by one-stage posterior debridement, transforaminal lumbar interbody fusion (TLIF) and instrumentation and combined posterior and anterior approaches for lumbar spinal tuberculosis, and determine the clinical effectiveness of the posterior only surgical treatment for lumbar spinal TB at the same time.

Methods

Thirty-seven patients who suffered lumbar tuberculosis were treated by two different surgical procedures in our center from May 2004 to June 2012. All the cases were divided into two groups: 19 cases in Group A underwent one-stage posterior debridement, TLIF and instrumentation, and 18 cases in Group B underwent posterior instrumentation, anterior debridement and bone graft in a single-stage procedure. The operation time, blood loss, lumbar kyphotic angle, recovery of neurological function and fusion time were, respectively, compared between Group A and Group B.

Results

The average follow-up period for Group A was 46.6 ± 16.7 months, and for Group B, 47.5 ± 15.0 months. It was obvious that the average operative duration and blood loss of Group A was less than those of Group B. Lumbar tuberculosis was completely cured and the grafted bones were fused in 10 months in all patients. There was no persistence or recurrence of infection and no differences in the radiological results in both groups. The kyphosis was significantly corrected after surgical management. The average pretreatment ESR was 60.7 ± 22.5 mm/h, which became normal (9.0 ± 2.8 mm/h) within 3 months in all patients.

Conclusions

Surgical management by one-stage posterior debridement, TLIF and instrumentation for lumbar tuberculosis is feasible and effective. This approach obtained better clinical outcomes than combined posterior and anterior surgeries.     

腰椎微创极外侧经椎间孔椎体间融合术的生物力学评价

目的 通过生物力学测试比较腰椎微创极外侧经椎间孔椎体间融合术(E-TLIF)与传统术式的生物力学稳定性.方法 采用正常猪脊柱运动节段标本24副,随机进行不同处理后分为正常对照组(CG组)、单纯椎弓根螺钉内固定组(SG组)、经椎间孔腰椎体间融合术(TLIF)组、E-TLIF组;分别测试不同载荷时各组在轴向压缩、前屈、后伸、左侧屈时的应变、位移变化及左侧扭转稳定性等生物力学指标,并进行统计学比较.结果 E-TLIF组的载荷-应变和位移、最大载荷下轴向稳定性、扭转稳定性等生物力学指标与TLIF组比较差异无统计学意义(P＞0.05).在左侧屈活动中,E-TLIF组[线性位移(3.40 ±0.09)mm,角位移2.57°±0.12°]稳定性优于TLIF组[线性位移(3.98 ±0.22)mm,角位移3.03°±0.18°](t=2.61,P＜0.05),E-TLIF组和TLIF组在轴向(前屈、后伸)、侧屈、旋转方向上的力学稳定性均高于SG组(t=4.17 ～4.53,P＜0.01).结论 E-TLIF手术是一种安全、有效的腰椎椎体间融合术式.     

Anterior lumbar interbody fusion in comparison with transforaminal lumbar interbody fusion: implications for the restoration of foraminal height, local disc angle, lumbar lordosis, and sagittal balance

OBJECT: A primary consideration of all spinal fusion procedures is restoration of normal anatomy, including disc height, lumbar lordosis, foraminal decompression, and sagittal balance. To the authors' knowledge, there has been no direct comparison of anterior lumbar interbody fusion (ALIF) with transforaminal lumbar interbody fusion (TLIF) concerning their capacity to alter those parameters. The authors conducted a retrospective radiographic analysis directly comparing ALIF with TLIF in their capacity to alter foraminal height, local disc angle, and lumbar lordosis. METHODS: The medical records and radiographs of 32 patients undergoing ALIF and 25 patients undergoing TLIF from between 2000 and 2004 were retrospectively reviewed. Clinical data and radiographic measurements, including preoperative and postoperative foraminal height, local disc angle, and lumbar lordosis, were obtained. Statistical analyses included mean values, 95% confidence intervals, and intraobserver/interobserver reliability for the measurements that were performed. RESULTS: Our results indicate that ALIF is superior to TLIF in its capacity to restore foraminal height, local disc angle, and lumbar lordosis. The ALIF procedure increased foraminal height by 18.5%, whereas TLIF decreased it by 0.4%. In addition, ALIF increased the local disc angle by 8.3 degrees and lumbar lordosis by 6.2 degrees, whereas TLIF decreased the local disc angle by 0.1 degree and lumbar lordosis by 2.1 degrees. CONCLUSIONS: The ALIF procedure is superior to TLIF in its capacity to restore foraminal height, local disc angle, and lumbar lordosis. The improved radiographic outcomes may be an indication of improved sagittal balance correction, which may lead to better long-term outcomes as shown by other studies. Our data, however, demonstrated no difference in clinical outcome between the two groups at the 2-year follow-up.     

Restoration of lordosis and disk height after single‐level transforaminal lumbar interbody fusion

Objective: To study radiographic and clinical outcomes after transforaminal lumbar interbody fusion (TLIF) in order to determine the impact of TLIF on lumbar lordosis, intervertebral height and improvement in clinical outcome measures. Methods: Forty‐five patients who had undergone a single‐level TLIF procedure for a single‐level degenerative condition were retrospectively reviewed and their clinical histories, degree of pre‐ and post‐operative lumbar lordosis, intervertebral height, and cage position recorded. Clinical assessment included use of modified Odom's criteria and a visual analog scale (VAS) for back and leg pain. Results: At 21 months, the patients had gained an average of 3.6° of lumbar lordosis and 4.5 mm disc height. Change in disc height was significantly associated with an anterior cage position while lumbar lordosis was unaffected by cage position. A spondylolisthesis subgroup demonstrated 31% reduction in the magnitude of anterior slip. Less lordosis was associated with worse back and leg pain as assessed by VAS and greater disk heights were associated with higher Odom's criteria scores. Patients with persistent leg pain at final follow‐up had less lumbar lordosis and intervertebral height than patients without leg pain. Conclusions: Intervertebral height and lumbar lordosis reconstruction are important for achieving good surgical results; guidance regarding the likely changes in lumbar lordosis and disk height after TLIF is provided by our findings.