Aims. The aim of this study was to reassess the rate of neurological, psoas-related, and abdominal complications associated with L4-L5 lateral lumbar interbody fusion (LLIF) undertaken using a standardized preoperative assessment and surgical technique. Methods. This was a multicentre retrospective study involving consecutively enrolled patients who underwent L4-L5 LLIF by seven surgeons at seven institutions in three countries over a five-year period. The demographic details of the patients and the details of the surgery, reoperations and complications, including femoral and non-femoral neuropraxia, thigh pain, weakness of hip flexion, and abdominal complications, were analyzed. Neurological and psoas-related complications attributed to LLIF or posterior instrumentation and persistent symptoms were recorded at one year postoperatively. Results. A total of 517 patients were included in the study. Their mean age was 65.0 years (SD 10.3) and their mean BMI was 29.2 kg/m. 2. (SD 5.5). A mean of 1.2 levels (SD 0.6) were fused with LLIF, and a mean of 1.6 (SD 0.9) posterior levels were fused. Femoral neuropraxia occurred in six patients (1.2%), of which four (0.8%) were LLIF-related and two (0.4%) had persistent symptoms one year postoperatively. Non-femoral neuropraxia occurred in nine patients (1.8%), one (0.2%) was LLIF-related and five (1.0%) were persistent at one year. All LLIF-related neuropraxias resolved by one year. A total of 32 patients (6.2%) had thigh pain, 31 (6.0%) were LLIF-related and three (0.6%) were persistent at one year. Weakness of hip flexion occurred in 14 patients (2.7%), of which eight (1.6%) were LLIF-related and three (0.6%) were persistent at one year. No patients had bowel injury, three (0.6%) had an intraoperative vascular injury (not LLIF-related), and five (1.0%) had ileus. Reoperations occurred in five patients (1.0%) within 30 days, 37 (7.2%) within 90 days, and 41 (7.9%) within one year postoperatively. Conclusion. LLIF involving the L4-L5 disc level has a low rate of persistent neurological, psoas-related, and abdominal complications in patients with the appropriate indications and using a standardized surgical technique. Cite this article: Bone Joint J 2024;106-B(1):53–61

The presacral retroperitoneal approach for axial lumbar interbody fusion (presacral ALIF) is not widely reported, particularly with regard to the mid-term outcome. This prospective study describes the clinical outcomes, complications and rates of fusion at a follow-up of two years for 26 patients who underwent this minimally invasive technique along with further stabilisation using pedicle screws. The fusion was single-level at the L5-S1 spinal segment in 17 patients and two-level at L4–5 and L5-S1 in the other nine. The visual analogue scale for pain and Oswestry Disability Index scores were recorded pre-operatively and during the 24-month study period. The evaluation of fusion was by thin-cut CT scans at six and 12 months, and flexion-extension plain radiographs at six, 12 and 24 months. Significant reductions in pain and disability occurred as early as three weeks postoperatively and were maintained. Fusion was achieved in 22 of 24 patients (92%) at 12 months and in 23 patients (96%) at 24 months. One patient (4%) with a pseudarthrosis underwent successful revision by augmentation of the posterolateral fusion mass through a standard open midline approach. There were no severe adverse events associated with presacral ALIF, which in this series demonstrated clinical outcomes and fusion rates comparable with those of reports of other methods of interbody fusion

Aims. We compared the clinical and radiological outcomes of using a polyetheretherketone cage with (TiPEEK) and without a titanium coating (PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF). Materials and Methods. We conducted a randomised clinical pilot trial of 40 patients who were scheduled to undergo a TLIF procedure at one or two levels between L2 and L5. The Oswestry disability index (ODI), EuroQoL-5D, and back and leg pain were determined pre-operatively, and at three, six, and 12 months post-operatively. Fusion rates were assessed by thin slice CT at three months and by functional radiography at 12 months. Results. At final follow-up, one patient in each group had been lost to follow-up. Two patients in each of the PEEK and TiPEEK groups were revised for pseudarthrosis (p = 1.00). The rate of complete or partial fusion at three months was 91.7% in both groups. Overall, there were no significant differences in ODI or in radiological outcomes between the groups. Conclusion. Favourable results with identical clinical outcomes and a high rate of fusion was seen in both groups. The titanium coating appears to have no negative effects on outcome or safety in the short term. A future study to determine the effect of titanium coating is warranted. Cite this article: Bone Joint J 2017;99-B:1366–72

Introduction. In daily clinical practice, progression of spinal fusion is typically monitored during clinical follow-up using conventional radiography and Computed Tomography scans. However, recent research has demonstrated the potential of implant load monitoring to assess posterolateral spinal fusion in an in-vivo sheep model. The question arises to whether such a strain sensing system could be used to monitor bone fusion following lumbar interbody fusion surgery, where the intervertebral space is supported by a cage. Therefore, the aim of this study was to test human cadaveric lumbar spines in two states: after a transforaminal lumbar interbody fusion (TLIF) procedure combined with a pedicle-screw-rod-construct (PSR) and subsequently after simulating bone fusion. The study hypothesized that the load on the posterior instrumentation decreases as the segment stiffens due to simulated fusion. Method. A TLIF procedure with PSR was performed on eight human cadaveric spines at level L4-L5. Strain sensors were attached bilaterally to the rods to derive implant load changes during unconstrained flexion-extension (FE), lateral bending (LB) and axial rotation (AR) loads up to ±7.5Nm. The specimens were retested after simulating bone fusion between vertebrae L4-L5. In addition, the range of motion (ROM) was measured during each loading mode. Result. The ROM decreased in the simulated bone fusion state in all loading directions (p≤0.002). In both states, the measured strain on the posterior instrumentation was highest during LB motion. Furthermore, the sensors detected a significant decrease in the load induced rod strain (p≤0.002) between TLIF+PSR and simulated bone fusion state in LB. Conclusion. Implant load measured via rod strain sensors can be used to monitor the progression of fusion after a TLIF procedure when measured during LB of the lumbar spine. However, further research is needed to investigate the influence of daily loading scenarios expected in-vivo on the overall change in implant load

Aims. Minimally invasive transforaminal lumbar interbody fusion (MITLIF) has been well validated in overweight and obese patients who are consequently subject to a higher radiation exposure. This prospective multicentre study aimed to investigate the efficacy of a novel lumbar localisation system for MITLIF in overweight patients. Patients and Methods. The initial study group consisted of 175 patients. After excluding 49 patients for various reasons, 126 patients were divided into two groups. Those in Group A were treated using the localisation system while those in Group B were treated by conventional means. The primary outcomes were the effective radiation dosage to the surgeon and the exposure time. Results. There were 62 patients in Group A and 64 in Group B. The mean effective dosage was 0.0217 mSv (standard deviation (. sd. ) 0.0079) in Group A and 0.0383 mSv (. sd. 0.0104) in Group B (p <  0.001). The mean fluoroscopy exposure time was 26.42 seconds (. sd. 5.91) in Group A and 40.67 seconds (. sd. 8.18) in Group B (p < 0.001). The operating time was 175.56 minutes (. sd. 32.23) and 206.08 minutes (. sd. 30.15) (p < 0.001), respectively. The mean pre-operative localisation time was 4.73 minutes (. sd. 0.84) in Group A and 7.03 minutes (. sd. 1.51) in Group B (p < 0.001). The mean screw placement time was 47.37 minutes (. sd. 10.43) in Group A and 67.86 minutes (. sd. 14.15) in Group B (p < 0.001). The pedicle screw violation rate was 0.35% (one out of 283) in Group A and 2.79% (eight out of 287) in Group B (p = 0.020). Conclusion. The study shows that the localisation system can effectively reduce radiation exposure, exposure time, operating time, pre-operative localisation time, and screw placement time in overweight patients undergoing MITLIF. Cite this article: Bone Joint J 2017;99-B:944–50

Purpose. A change in lumbar lordosis can affect the outcome following lumbar fusion, and intraoperative positioning is a prime determinant of the postoperative lordosis. The purpose of this study is to determine the change in lordosis and sacral slope (SS) following axial lumbar interbody fusion (AxiaLIF). Method. We retrospectively reviewed 81 patients who underwent a 360 lumbar interbody fusion at L4-5/L5-S1 (two-level procedure) or solely at L5-S1 (one-level) for degenerative disc disease and spondylolithesis utilizing the AxiaLIF with posterior segmental instrumentation. For the two-level procedures, 25 patients had the AxiaLIF placed first and 27 had pedicle screws placed first. For the one-level procedures, 11 patients had the AxiaLIF placed first and 18 had pedicle screws placed first. Standing lateral preoperative radiographs were compared to standing lateral postoperative films. Lumbar Cobb angles were measured at L1-S1, L4-S1 and individual lumbar levels. SS was measured for sacral version. Results. Of the 81 patients studied, 29 underwent one-level AxiaLIF, and 52 underwent two-level AxiaLIF. For the two-level population, there were statistically significant changes (P less than 0.05) in Cobb angles pre- vs. postoperative at the L4-S1, L2-3, and L4-5 levels, but none other. The percent lordosis from L4-S1 pre- vs. postoperative was also noted to be significant. The pre- vs. postoperative Cobb angle comparisons for the one-level population were not found to be significant. The percentages having a greater than or equal to 10 degree change in total lordosis and lordosis from L4-S1 in both one- and two-level groups were similar at ∼20%. There was no difference in either group in percentage having a greater than or equal to five degree change at individual lumbar segments although there was a trend at both L5-S1 and the SS towards less change with the pedicle screws placed first. Conclusion. A significant portion of both single and multilevel fusions with AxiaLIF had a statistically significant change at the L4-5 and L4-S1 levels. In general, there is a small decrease in lordosis at the bottom two segments and SS with reciprocal changes at the proximal levels. The percentage of total lordosis from the L4-S1 level decreased significantly in the multilevel group. Roussouly lordosis type three (well-balanced) was relatively protected from change in lordosis. Placing pedicle screws prior to placing the AxiaLIF in one- and two- level procedures may lead to an improved sagittal alignment. Further observation of this cohort will determine if the change in alignment will impact outcomes or accelerate adjacent level disease

To evaluate the findings of fusion of titanium interbody cages in a sheep lumbar interbody fusion model. Six sheep underwent lumbar discectomy and fusion at L3-L4 throught transperitoneal approach. An cervical threaded expanding and cylindrical cage packed with bone autografts was placed into intervertebral disc space. The sheeps were killed at 9, 12 and 18 months after surgery. The lumbar spines were excised, trimmed of residual musculature and underwent to plain radiographs and CT scans. The spines were dissected and sectioned using the EXAKT microgrinding device creating parasagittal and coronal sections. Plain radiographs demonstrated no lucent lines around the implants and no change in disc height. CT scans showed mineralized bone within the cages and bone in growth wit anterior bony bridging outside of the cages. Histologic characterizations indicated the presence of mature lamellar bone with osteonic systems filling the central area of the cage. Bone in growth on the surface of the implant is present near the fenestrations alone. A membrane of fibrous tissue layer is present on the external surface of any cage separating bone from the implant. Expanding titanium cages have shown mechanical and biological validity to achieve an optimal interbody fusion. Design of the cage showed a decisive role to provide superior endplate-to-endplate contact for unsurpassed strenght and stability and to agree the achievement of the interbody fusion across its fenestrations

Lateral lumbar interbody fusion (LLIF) has biomechanical advantages due to the preservation of ligamentous structures (ALL/PLL), and optimal cage height afforded by the strength of the apophyseal ring. We compare the biomechanical motion stability of multiple levels LLIF (4 segments) utilising PEEK interbody 26mm cages to stand-alone cage placement and with supplemental posterior fixation with pedicle screw and rods. Six lumbar human cadaver specimens were stripped of the paraspinal musculature while preserving the discs, facet joints, and osteoligamentous structures and potted. Specimens were tested under 5 conditions: intact, posterior bilateral fixation (L1-L5) only, LLIF-only, LLIF with unilateral fixation and LLIF with bilateral fixation. Non-destructive testing was performed on a universal testing machine (MTS Systems Corp) to produce flexion-extension, lateral-bending, and axial rotation using customized jigs and a pulley system to define a non-constraining load follower. Three-dimensional spine motion was recorded using a motion device (Optotrak). Results are reported for the L3-L4 motion segment within the construct to allow comparison with previously published works of shorter constructs (1-2 segments). In all conditions, there was an observed decrease in ROM from intact in flexion/extension (31%-89% decrease), lateral bending (19%-78%), and axial rotation (37%-60%). At flexion/extension, the decreases were statistically significant (p<0.007) except for stand-alone LLIF. LLIF+unilateral had similar decreases in all planes as the LLIF+bilateral condition. The observed ROM within the 4-level construct was similar to previously reported results in 1-2 levels for stand-alone LLIF and LLIF+bilateral. Surgeons may be concerned about the biomechanical stability of an approach utilizing stand-alone multilevel LLIF. Our results show that 4-level multilevel LLIF utilizing 26 mm cages demonstrated ROM comparable to short-segment LLIF. Stand-alone LLIF showed a decrease in ROM from the intact condition. The addition of posterior supplemental fixation resulted in an additional decrease in ROM. The results suggest that unilateral posterior fixation may be sufficient

Obesity is an increasing public health concern associated with increased perioperative complications and expense in lumbar spine fusions. While open and mini-open fusions such as transforaminal lumbar interbody fusion (TLIF) and minimally invasive TLIF (MIS-TLIF) are more challenging in obese patients, new MIS procedures like oblique lateral lumbar interbody fusion (OLLIF) may improve perioperative outcomes in obese patients relative to TLIF and MIS-TLIF. The purpose of this study is to determine the effects of obesity on perioperative outcomes in OLLIF, MIS-TLIF, and TLIF. This is a retrospective cohort study. We included patients who underwent OLLIF, MIS-TLIF, or TLIF on three or fewer spinal levels at a single Minnesota hospital after conservative therapy had failed. Indications included in this study were degenerative disc disease, spondylolisthesis, spondylosis, herniation, stenosis, and scoliosis. We measured demographic information, body mass index (BMI), surgery time, blood loss, and hospital stay. We performed summary statistics to compare perioperative outcomes in MIS-TLIF, OLLIF, and TLIF. We performed multivariate regression to determine the effects of BMI on perioperative outcomes controlling for demographics and number of levels on which surgeries were operated. OLLIF significantly reduces surgery time, blood loss, and hospital stay compared to MIS-TLIF, and TLIF for all levels. MIS-TLIF and TLIF do not differ significantly except for a slight reduction in hospital stay for two-level procedures. On multivariate analysis, a one-point increase in BMI increased surgery time by 0.56 ± 0.47 minutes (p = 0.24) in the OLLIF group, by 2.8 ± 1.43 minutes (p = 0.06) in the MIS-TLIF group, and by 1.7 ± 0.43 minutes (p < 0.001) in the TLIF group. BMI has positive effects on blood loss for TLIF (p < 0.001) but not for OLLIF (p = 0.68) or MIS-TLIF (p = 0.67). BMI does not have significant effects on length of hospital stay for any procedure. Obesity is associated with increased surgery time and blood loss in TLIF and with increased surgery time in MIS-TLIF. Increased surgery time may be associated with increased perioperative complications and cost. In OLLIF, BMI does not affect perioperative outcomes. Therefore, OLLIF may reduce the disparity in outcomes and cost between obese and non-obese patients

The objective of this study was to investigate the effects of different doses rhBMP-2 on bone healing in an ovine lumbar interbody fusion model. In this study 22 sheep underwent two level lumbar interbody fusion using a ventrolateral approach with secondary dorsal fixation at L1/2 and L3/4. After randomization in one level a PEEK-cage was implanted filled with one of three doses rhBMP-2 (0,5mg; 1mg; 2mg) delivered on an ACS. The other level received an empty PEEK-cage or ACS filled cage. Animals were sacrificed after 3 and 6 months and decalcified histology was performed. This included histomorphological analysis well as histomorphometry of the tissues within the cage. At 3 months after surgery the groups treated with rhBMP-2 showed higher amounts of bone tissue within the cage. At 6 months the amounts of bone tissue increased in all groups, were still lower in the groups without growth factor. At 3 months there was only one active osteolysis in the cage/ACS. 7 of 8 segments of the rhBMP-2 groups had a compromised bone structure around the implant. These areas were filled with fibrous tissue and fibrocartilage. This finding was not detected in the groups without rhBMP-2 at 3 months. At 6 months most of the segments with an empty cage or cage/ACS showed a chronic inflammation. Predominant cells were macrophages and giant cells. The groups treated with rhBMP-2 showed only a few mild chronic inflammatory reactions. The well-known dose dependent effect of rhBMP-2 on bone healing could also be recognized in our study. Attention has to be payed to the proinflammatory properties of the growth factor. Consistent with other studies we found 2 strong inflammatory reactions, each one in the lowest and highest dose group. Also, the potential for causing transient bone resorptions, according to the results of others, was demonstrated. At 3 months 7 of 8 segments treated with rhBMP-2 showed compromised peri-implant bone. Osteoblasts, but not osteoclasts, were seen in the periphery of these areas. It can be concluded that there where bone resorptions which already merged into an increased osteoblastic activity. Usually resorptions occur between 2 and 12 weeks and are followed by a period of increased osteoblastic activity. This finding wasn't recognized at 6 months anymore. Striking is that at 6 months most of the segments without rhBMP-2 showed a compromised bone structure around the implant with a mild to mainly moderate chronic inflammatory reaction. This cannot be attributed to the growth factor. Also, the ACS is degraded at 6 months and is unlikely a possible explanation. Therefore, the cage as a reason must be considered and it has to be questioned whether PEEK is the optimal material for interbody cages

In a prospective observational study we compared the two-year outcome of lumbar fusion by a simple technique using translaminar screws (n = 57) with a more extensive method using transforaminal lumbar interbody fusion and pedicular screw fixation (n = 63) in consecutive patients with degenerative disease of the lumbar spine. Outcome was assessed using the validated multidimensional Core Outcome Measures Index. Blood loss and operating time were significantly lower in the translaminar screw group (p < 0.01). The complication rates were similar in each group (2% to 4%). In all, 91% of the patients returned their questionnaire at two-years. The groups did not differ in Core Outcome Measures Index score reduction, 3.6 (. sd. 2.5) (translaminar screws) vs 4.0 (. sd. 2.8) (transforaminal lumbar interbody fusion) (p = 0.39); ‘good’ global outcomes, 78% (translaminar screws) vs 78% (transforaminal lumbar interbody fusion) (p = 0.99) or satisfaction with treatment, 82% (translaminar screws) vs 86% (transforaminal lumbar interbody fusion) (p = 0.52). The two fusion techniques differed markedly in their extent and the cost of the implants, but were associated with almost identical patient-orientated outcomes. Extensive three-point stabilisation is not always required to achieve satisfactory patient-orientated results at two years

Purpose: Circumferential arthrodesis of the lumbar spine is necessary in certain selected situations (lumbar stenosis with instability and preserved disc height or spondylolisthesis). Posterior lumbar interbody fusion (PLIF) raises the risk of significant bleeding and fibrosis around the roots as well as neurological complications. Transforaminal lumbar interbody fusion (TLIF) can avoid excessive bleeding and root displacement. The cages are inserted via a unilateral approach. Material and methods: This prospective single-centre study included twenty patients (nine men and eleven women), mean age 49 years. Indications for lumbar surgery were degenerative spondylolisthesis in nine patients and discal lumbar pain with foraminal stenosis in five. The clinical status was assessed with the Oswestry score, SF-36 and a visual analogue scale (VAS). Radiological assessment was based on inter-body fusion, segmentary lordosis, and lumbopelvic parameters. TLIF was associated with a posterior approach for insertion of titanium pedicular screws (CDH, Medtronic Sofamor Danek). Temporary unilateral distraction opened the foramen. Unilateral arthrectomy enabled a lateral approach to the disc without involving the roots and avoiding any movement of the dural sac. The disc was resected and the body endplates were prepared before introducing two cages (pyramesh) filled with macroporous ceramic granules (BCP) mixed with autologous bone marrow. Installation to two contourned rods enabled segmentary compression to stabilise the cages in association with posterolateral fusion. Results: Mean operative time was three hours. Mean blood loss was 400 ml. The patients were verticalised on day three without a corset. Mean follow-up was six months with retrospective evaluation of the Oswestry score, SF-36, and VAS. Postoperative pain resolved rapidly. Two patients developed transient incomplete L5 deficit. Bony bridges around the cases and posterolaterally were identified on the six-month x-rays. Spine view confirmed the quality of the fusion and lumbopelvic parameters revealed restoration of segmentary lordosis. Conclusion: The unilateral approach for TLIF is a reliable technique which does not compromise the roots. It enables very reliable primary stability and recovery of local segmentary lordosis. We are developing a minimally invasive percutaneous technique for this procedure

Transforaminal lumbar interbody fusion (TLIF) using an implanted cage is the gold standard surgical treatment for disc diseases such as disc collapse and spinal cord compression, when more conservative medical therapy fails. Titanium (Ti) alloys are widely used implant materials due to their superior biocompatibility and corrosion resistance. A new Ti-6Al-4V TLIF cage concept featuring an I-beam cross-section was recently proposed, with the intent to allow bone graft to be introduced secondary to cage implantation. In designing this cage, we desire a clear pathway for bone graft to be injected into the implant, and perfused into the surrounding intervertebral space as much as possible. Therefore, we have employed shape optimization to maximize this pathway, subject to maintaining stresses below the thresholds for fatigue or yielding. The TLIF I-beam cage (Fig. 1(a)) with an irregular shape was parametrically designed considering a lumbar lordotic angle of 10°, and an insertion angle of 45° through the left or right Kambin's triangles with respect to the sagittal plane. The overall cage dimensions of 30 mm in length, 11 mm in width and 13 mm in height were chosen based on the dimensions of other commercially available cages. The lengths (la, lp) and widths (wa, wp) of the anterior and posterior beams determine the sizes of the cage's middle and posterior windows for bone graft injection and perfusion, so they were considered as the design variables for shape optimization. Five dynamic tests (extension/flexion bending, lateral bending, torsion, compression and shear compression, as shown in Fig. 2(b)) for assessing long term cage durability (10. 7. cycles), as described in ASTM F2077, were simulated in ANSYS 15.0. The multiaxial stress state in the cage was converted to an equivalent uniaxial stress state using the Manson-Mcknight approach, in order to test the cage based on uniaxial fatigue testing data of Ti-6Al-4V. A fatigue factor (K) and a critical stress (σcr) was introduced by slightly modifying Goodman's equation and von Mises yield criterion, such that a cage design within the safety design region on a Haigh diagram (Fig. 2) must satisfy K ≤ 1 and σcr ≤ SY = 875 MPa (Ti-6Al-4V yield strength) simultaneously. After shape optimization, a final design with la = 2.30 mm, lp = 4.33 mm, wa = 1.20 mm, wp = 2.50 mm, was converged upon, which maximized the sizes of the cage's windows, as well as satisfying the fatigue and yield strength requirements. In terms of the strength of the optimal cage design, the fatigue factor (K) under dynamic torsion approaches 1 and the critical stress (σcr) under dynamic lateral bending approaches the yield strength (SY = 875 MPa), indicating that these two loading scenarios are the most dangerous (Table 1). Future work should further validate whether or not the resulting cage design has reached the true global optimum in the feasible design space. Experimental validation of the candidate TLIF I-beam cage design will be a future focus. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

The purpose of this study was to investigate the efficacy and fusion rates of a unilateral pedicle screw construct supplemented with a translaminar screw in transforaminal lumbar interbody fusion (TLIF). The construct was used with an aim of providing suitable spine stiffness with minimal implant load for spinal fusion. Nineteen consecutive patients who underwent single level TLIF were included in the study. All patients had posterior spinal instrumentation using a unilateral pedicle screw construct with a contralateral translaminar screw. Patients were assessed preoperatively and at two, six, twelve and twenty-four weeks following surgery and at the end of one and two years. At every visit Oswestry disability index score,Visual analogue scale for pain and a pain diagram were recorded. A radiographic exam was also conducted and CT scan was done if there was concern about fusion. The average follow up was twenty-four months. There were twelve males and seven females with an average age of forty-eight years. All patients went on to clinical and radiographic union. Sixteen of nineteen patients had significant clinical improvement on VAS for pain, Oswestry scores and pain medication. Three patients had recurrence of radicular pain on the side of the TLIF leading to reexploration. In all three patients solid fusion was observed but scar tissue was evident and symptoms resolved following redecompression of the foramen. The biomechanical competence of a construct is evidenced by successful fusion. With the advent of minimally invasive techniques to achieve spinal fusion the goal is to use minimal instrumentation without compromising on the final stiffness of the spine. The construct of unilateral pedicle screws supplemented with a trans-laminar screw led to fusion in all our cases. It requires lesser soft tissue dissection and the posterior implants are 56% cheaper

Study design. Prospective randomized study. Objective. Primary aim of this study was to compare clinical and radiological results of transforaminal lumbar interbody fusion (TLIF) with posterolateral (interlaminar) instrumented lumbar fusion (PLF) in adult low grade (Meyerding 1 & 2) spondylolisthesis patients. Background data. Theoretically, TLIF has better radiological result than PLF in spondylolisthesis in most of the studies. Method. 24 patients of low grade adult spondylolisthesis were randomly allocated to one of the two groups: group 1- PLF and group 2-TLIF. Study period was between August 2010 to March 2013. All patients were operated by a single surgeon (CN). Posterior decompression was performed in all patients. Average follow up period was 18.4 months. Quality of life was accessed with Visual analogue scale and Oswestry Low Back Pain Disability Index. Fusion was assessed radiologically by CT scan and X-ray. Result. Though fusion was significantly better in TLIF group, clinical outcome including relief of back pain and neurogenic claudication were better in PLF group. Rate of complication was also lower in PLF group. Conclusion. Considering the low complication rate and similar or better clinical results, posterolateral instrumented lumbar fusion is the better option in low grade adult spondylolisthesis

Background Context. Different minimally invasive approaches to the lumbar spine have been proposed but they can be associated with increased risk of complications, steep learning curve and longer operative time. Purpose. To report the complications associated with a minimally invasive technique of retroperitoneal anterolateral approach to the lumbar spine. Study design. Retrospective study of 179 patients who underwent anterior oblique lumbar interbody fusion (OLIF). Methods. A total of 179 patients with previous posterior instrumented fusion undergoing OLIF were included. This muscle-splitting approach consists in anterolateral exposure through a 4 cm incision followed by placement of a PEEK cage filled with bone graft and/or substitute. Results. Patients were aged 54.110.6 years with BMI of 24.84.1 kg/m2. Length of follow-up was (0.90.7 years), including 17 patients with a minimum follow-up of 2 years. A left-sided approach was done in 174 patients. The procedure was performed at L1–2 in 4, L2–3 in 54, L3–4 in 120, L4–5 in 134 and L5-S1 in 6 patients. It was done at 1 level in 56, 2 levels in 107, and 3 levels in 16 patients. Operative time and blood loss were respectively 32.513.2 min and 57131 cc per level fused. There were 19 patients with single complication and one with two complications, including two patients with postoperative radiculopathy after L3–5 OLIF. There was no abdominal weakness or herniation. Conclusion. Minimally invasive OLIF can be performed easily and safely from L2 to L5, and at L1–2 and L5-S1 for selected cases. Up to 3 levels can be addressed through a “sliding window”. It is associated with minimal blood loss and short operative time. The risk of complications is similar to that reported for traditional anterior approaches, with the advantage of decreasing the risk of abdominal wall weakness or herniation

Purpose of the study: Revision surgery for scoliosis in adults is a technical challenge. Indications include flat back, non-union, and syndromes adjacent to the instrumentation The purpose of this work was to evaluate the pertinence of the transforaminal lumbar interbody fusion (TLIF) method for revision surgery for scoliosis in adults. Material and methods: In our spinal surgery unit, 23 patients underwent revision surgery for thoracolumbar and lumbar scoliosis. A unique posterior approach was used. The TLIF was performed systematically at the lumbosacral level, at the non-union when it was present, and at the level of the Smith-Petersen osteotomies, as well as the levels above and below a transpedicular osteotomy. Seventeen patients presented flat back, ten non-union, five degenerative disease distal to the instrumentation and one degeneration proximal to the instrumentation. Nine patients had several indications for surgical revision. Five transpedicular osteotomies were performed in five patients. Results: Mean follow-up was 30 months (range 18–48). On average 2.3 levels (range 1–4) were involved in the TLIF. The fusion was extended to the sacrum in 22 patients. The mean operative time was 5h50m (range 3–8 hours). Mean blood loss was 2100ml (400–4500). Postoperative lumbar lordosis (L1S1) was 53.5°, giving an improvement of 23° copared with the preoperative lordosis. Among the postoperative complications, there was one neurological complications which recovered partially at last follow-up one case of deep infection of the operative site which require partial removal of the implants and one case of recurrent non-union. There was no loss of correction in the frontal or sagittal planes with the exception of one patient who developed an infection. None of the patients in the series required complementary anterior surgery. Conclusion: For revision surgery of scoliosis in the adult, a circumferential arthrodeis is needed to maintain the fusion. The TLIF method has the advantage of allowing intersomatic fusion via the posterior approach alone without opening the spinal canal. We consider that the TLIF technique is an alternative to two-phase procedures for revision surgery for scoliosis in adults. This method has given a good percentage of fusion in our series with little loss of correction

The use of lumbar fusion procedures in the USA and Europe has rapidly increased over the last decade and a large number of these procedures involve the use of bone grafts. Despite of technical progress of spinal surgery and operative materials the risk of vertebral fusion failure occurs in 5 – 35 % of cases. Autografting has been considered the gold standard for bone graft procedures. However, the harvesting from the iliac crest can be associated with short and long-term morbidity in up to 22 % of cases. Main goal of this experimental study was to compare newly developed hybrid biodegradable nanocomposit porous implant (HBNPI) against bone craft from iliac crest as a new and better alternative for lumbar interbody fusion. 24 male pigs 4 months old weighting around 40 Kg were included in our study. These pigs were divided into two study groups depending on fusion method. Group A – 12 pigs underwent lateral lumbal interbody fusion (L2/3) with implantation of iliac crest bonegraft. Group B - 12 pigs underwent lateral lumbal interbody fusion (L2/3) with newly developed HBNPI. Each group were divided into two subgroups from these 6 spines were harvested 8 weeks (subgroup A1, B1) and 6 spines 16 weeks (group A2, B2) after surgery. After sacrifice, the lumbar spines were taking out and micro-CT, biomechanical testing and histomorphological analysis in all groups were performed to evaluate a quality of intervertebral fusion. As controls (group N), 6 cadaveric intact lumbar spines underwent biomechanical, micro-CT and histological testing. All 24 animals recovered from general anesthesia without unusual events. The operations lasted between 50–90 minutes (mean 70) in Group A and between 35–72 minutes (mean 43) in Group B. All of the pigs from group A could stand up and were mobile within 20 hours (range 7–20). When bone graft harvesting was not necessary (group B) this time was shortened, ranging from 1 – 1,5 hour. All pigs from Group A were limping on the first postoperative day. No limping animal was observed in group B. Total body weight of the pigs increased from 37 kg (range 36–40) at the start to 85 (range 80–89) at sacrifice. Biomechanics evaluation shows that extension flexural stiffness values are statistically significantly different between A2 (16 weeks post-implant) and A1 (8 weeks post-implant). Group A2 achieves higher values than Group A1, which is attributed to the adhesion of the implant to the surrounding vertebrae. Similarly, this also applies to groups B2 and B1. The flexural stiffness at group B2 extension is statistically significantly higher than the A2 group and also than the native N group. Biomechanical evaluation supports findings on micro-CT and histological specimens, where both adjacent vertebrae are completely fused in groups B2, unlike in group A2, where there is no or incomplete fusion. Newly developed HBNPI represents new possibility how to do intervertebral fusion, and simultaneous become chance how to improve and accelerate bone healing process against standard procedures

Purpose: To review the sagittal lumbar and clinical profile of the two surgical procedures: TLIF (transforaminal lumbar interbody fusion and ALIF (anterior lumbar interbody fusion). Materials and methods: We carried out a retrospective study of 46 patients who underwent circumferential fusion in 2000–2001. TLIF was used in the first group (21) and ALIF in the second (25). The posterior approach with pedicle instrumentation was used in all patients. Lateral radiographs of the lumbar spine in neutral position and bipedestation were used for evaluation before and after surgery and during follow-up. The results were compared statistically using the Wilcoxon matched pairs test. Results: Lumbar lordosis was achieved with both techniques: TLIF+PF(posterior fusion) −33° (preoperative), −46° (postoperative) and ALIF+ PF −49° (preoperative), −54° (postoperative). However the height of the disc improved significantly with the anterior approach: TLIF+ PF 0.62 (preoperative), 1.35 (postoperative) and ALIF+PF 1 (preoperative), 4.65 (postoperative). The duration of surgery, blood loss and hospital stay were greater with ALIF+PF than with TLIF+PF. Conclusions: TLIF+PF has clinical and economic advantages over ALIF+PF. Lumbar lordosis and the area of instrumented lordosis was achieved with both circumferential fusion procedures and the only radiographic difference was the restoration of the disc height with ALIF

Introduction Circumferential fusion is becoming increasingly popular and has been advocated by many authors to improve the fusion rates and clinical outcomes of the degenerative lumbosacral spine. Anterior lumbar interbody fusion (ALIF) with posterolateral fusion does provide direct access to the disc via a separate incision/ approach but has inherent neurovascular risks. Posterior lumbar interbody fusion (PLIF) with posterolateral fusion mandates bilateral exposure with significant retraction of neural elements with higher incidence of postoperative radiculitis. PLIF also reduces surface area for fusion and disrupts the posterior tension band. TLIF allows for a circumferential fusion through a single posterior incision with only slight retraction of the thecal sac and nerve roots, with much less morbidity and costs as compared to traditional PLIF and ALIF techniques. To our knowledge, there are no studies that report radiographic and clinical results of using recombinant human bone morphogenic protein (rhBMP-2) and allograft in a TLIF setting. The purpose of this study was to assess clinical & radiographic outcomes of patients treated with one or two level instrumented transforaminal lumbar interbody fusions (TLIF) performed with allograft and rh-BMP2 for treatment of symptomatic spondylolisthesis or degenerative disc disease. Methods During a consecutive 13 month period, 77 patients underwent TLIF procedures utilizing rhBMP-2 by one spine surgeon for lumbosacral degenerative and deformity conditions with simultaneous posterolateral fusions with allograft. Pedicle screw instrumentation (Monarch, DePuy Spine) provided distraction and a carbon-fiber curvilinear cage (Leopard, Depuy Spine) packed with rhBMP-2 (Large II Kit, total graft volume 8ml onto 77.4 sq. cm collagen sponge; Infuse: Medtronic Sofamor Danek) was placed into the disk space after hemifacetectomy and discectomy. The patients were followed at two weeks and three, six, 12 and 24 months after surgery patients were followed with several functional parameters such as the visual analog scale (VAS), SF-36 and Oswestry Disability Index (ODI) questionnaires. Fusion was assessed by static and dynamic radiographs at 6, 12, and 24 months as well as CT scans at 24 months. Results 71 patients were available for follow-up (92%) evaluation (mean 16 months; range 6–24 months). At 24 months, 85 percent and 81 percent of patients had improvement over preoperative ODI and SF-36 measures respectively. At 24 months, 70% of patients had good to excellent outcomes by both ODI and SF-36. We achieved 94% fusion rate with only four pseudarthroses. There was one wound infection treated with hardware removal and intravenous antibiotics. One patient had excessive bone growth into the foramen, necessitating surgical decompression with subsequent excellent clinical outcome. Ten patients had paresthesias on the side of the TLIF, all of which resolved by three weeks. There were no permanent neurologic deficits. Discussion The use of rhBMP-2 inside the cage, in combination with posterolateral allograft, can provide a high fusion rate and good clinical outcomes in a TLIF setting. The morbidity associated with iliac crest bone graft is avoided, with fusion rates approaching that of a true anterior/posterior circumferential fusion. Complications were few, with no significant neurologic sequelae from the placement of a structural graft into the anterior column through a posterior approach. Overgrowth of bone into the neural foramen, likely related to the residue of rhBMP-2 at the TLIF entry site, can occur. Care must be taken to place the TLIF cage device and the contained rhBMP-2 into the anterior half of the disk space to minimize the risk of this complication