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

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

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. People with severe, persistent low back pain (LBP) may be offered lumbar spine fusion surgery if they have had insufficient benefit from recommended non-surgical treatments. However, National Institute for Health and Care Excellence (NICE) 2016 guidelines recommended not offering spinal fusion surgery for adults with LBP, except as part of a randomized clinical trial. This survey aims to describe UK clinicians’ views about the suitability of patients for such a future trial, along with their views regarding equipoise for randomizing patients in a future clinical trial comparing lumbar spine fusion surgery to best conservative care (BCC; the FORENSIC-UK trial). Methods. An online cross-sectional survey was piloted by the multidisciplinary research team, then shared with clinical professional groups in the UK who are involved in the management of adults with severe, persistent LBP. The survey had seven sections that covered the demographic details of the clinician, five hypothetical case vignettes of patients with varying presentations, a series of questions regarding the preferred management, and whether or not each clinician would be willing to recruit the example patients into future clinical trials. Results. There were 72 respondents, with a response rate of 9.0%. They comprised 39 orthopaedic spine surgeons, 17 neurosurgeons, one pain specialist, and 15 allied health professionals. Most respondents (n = 61,84.7%) chose conservative care as their first-choice management option for all five case vignettes. Over 50% of respondents reported willingness to randomize three of the five cases to either surgery or BCC, indicating a willingness to participate in the future randomized trial. From the respondents, transforaminal interbody fusion was the preferred approach for spinal fusion (n = 19, 36.4%), and the preferred method of BCC was a combined programme of physical and psychological therapy (n = 35, 48.5%). Conclusion. This survey demonstrates that there is uncertainty about the role of lumbar spine fusion surgery and BCC for a range of example patients with severe, persistent LBP in the UK. Cite this article: Bone Jt Open 2024;5(7):612–620

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

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

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

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.

The December 2024 Spine Roundup. 360. looks at: Rostral facet joint violations in robotic- and navigation-assisted pedicle screw placement; The inhibitory effect of non-steroidal anti-inflammatory drugs and opioids on spinal fusion: an animal model;L5-S1 transforaminal lumbar interbody fusion is associated with increased revisions compared to L4-L5 TLIF at two years; Immediate versus gradual brace weaning protocols in adolescent idiopathic scoliosis: a randomized clinical trial; Effectiveness and cost-effectiveness of an individualized, progressive walking, and education intervention for the prevention of low back pain recurrence in Australia (WalkBack): a randomized controlled trial; Usefulness and limitations of intraoperative pathological diagnosis using frozen sections for spinal cord tumours; Effect of preoperative HbA1c and blood glucose level on the surgical site infection after lumbar instrumentation surgery; How good are surgeons at achieving their alignment goals?

There is limited long term evidence to support instrumented fusion as an adjunct to decompression for foraminal stenosis in the presence of single level degenerative disc disease. We report the long term outcome of a prospective randomised controlled trial. Forty-four patients with single-level disc disease were randomly assigned to three groups (spinal decompression (Group 1), decompression and instrumented posterolateral fusion (Group 2), or decompression and instrumented posterolateral fusion plus transforaminal interbody fusion (Group 3). Spinal disability (Dallas, Roland Morris, and Lower Back Outcome Score [LBOS]), and quality of life (EuroQol (EQ) and short form (SF-) 36 questionnaires) were assessed before and at after surgery by independent researchers. At mean of 15 years follow up 33 (75%) patients were available for assessment. All groups observed a significant improvement in the EQ-5D at final follow up. Group 1 demonstrated significantly better functional outcome at final follow up according to the Dallas, Roland Morris, LBOS, and EQ-5D (3L and VAS) scores when compared to the other two groups (p<0.01). The SF-36 score demonstrated that group 1 had significantly better generic health scores compared to groups 2 and 3. Regression analysis was used to adjust for the differences in general health between the groups and demonstrated no significant difference between the groups in the spine specific scores: Dallas (p>0.15), Roland Morris (p>0.37), or the LBOS (p>0.32). Fusion in combination with decompression for the treatment of foraminal stenosis and single level degenerative disc disease offers no long term functional benefit over decompression in isolation

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

We carried out a prospective study to determine whether the addition of a recombinant human bone morphogenetic protein (rhBMP-2) to a machined allograft spacer would improve the rate of intervertebral body fusion in the spine. We studied 77 patients who were to undergo an interbody fusion with allograft and instrumentation. The first 36 patients received allograft with adjuvant rhBMP-2 (allograft/rhBMP-2 group), and the next 41, allograft and demineralised bone matrix (allograft/demineralised bone matrix group). Each patient was assessed clinically and radiologically both pre-operatively and at each follow-up visit using standard methods. Follow-up continued for two years. Every patient in the allograft/rhBMP-2 group had fused by six months. However, early graft lucency and significant (> 10%) subsidence were seen radiologically in 27 of 55 levels in this group. The mean graft height subsidence was 27% (13% to 42%) for anterior lumbar interbody fusion, 24% (13% to 40%) for transforaminal lumbar interbody fusion, and 53% (40% to 58%) for anterior cervical discectomy and fusion. Those who had undergone fusion using allograft and demineralised bone matrix lost only a mean of 4.6% (0% to 15%) of their graft height. Although a high rate of fusion (100%) was achieved with rhBMP-2, significant subsidence occurred in more than half of the levels (23 of 37) in the lumbar spine and 33% (6 of 18) in the cervical spine. A 98% fusion rate (62 of 63 levels) was achieved without rhBMP-2 and without the associated graft subsidence. Consequently, we no longer use rhBMP-2 with allograft in our practice if the allograft has to provide significant structural support

Purpose. Posterior lumbar fusion using minimally invasive surgical (MIS) techniques are reported to minimise postoperative pain, soft tissue damage and length of hospital stay when compared to the traditional open procedure. Methods. This is a review of patients who underwent MIS for posterolateral lumbar fusion in a single practice over a 2-year period. Results. Twenty-eight patients underwent this procedure. The median age was 57 (range 34-80). Male:female ratio was 1:1. The most common symptom was radicular pain (n=26). Two patients had back pain without radicular symptoms. Primary degenerative spondylolisthesis was seen in 22 patients and post-laminectomy spondylolisthesis in 3 patients. Transforaminal interbody fusion (TLIF) with pedicle screw fixation was the commonest procedure (20) while the rest had pedicle screw fixation and inter-transverse fusion. Along with fusion, nerve root decompression alone was performed in 19, while 5 had decompression of the central spinal canal. Intra-operative navigation was used to assist screw placement in 5 patients. The typical hospital stay was 3 days. All but two patients were mobilised the same or the following day. Twenty-one patients with radiculopathy (80%) reported improvement in VAS at 6-months. One patient suffered irreversible nerve root injury (L5). Significant pedicle breach without nerve injury by a screw was seen in one patient. Conclusion. Minimally invasive TLIF and pedicle screw fixation lumbar degenerative condition is a safe procedure with complications comparable to traditional open techniques. Minimal muscle dissection and soft tissue damage allows for earlier ambulation and reduced hospital stay. The procedure however required longer operative time and increased exposure to intra-operative x-rays

Lumbar fusion surgery is an established procedure for the treatment of several spinal pathologies. Despite numerous techniques and existing devices, common surgical trends in lumbar fusion surgery are scarcely investigated. The purpose of this Canada-based study was to provide a descriptive portrait of current surgeons’ practice and implant preferences in lumbar fusion surgery while comparing findings to similar investigations performed in the United Kingdom. Canadian Spine Society (CSS) members were sampled using an online questionnaire which was based on previous investigations performed in the United Kingdom. Fifteen questions addressed the various aspects of surgeons’ practice: fusion techniques, implant preferences, and bone grafting procedures. Responses were analyzed by means of descriptive statistics. Of 139 eligible CSS members, 41 spinal surgeons completed the survey (29.5%). The most common fusion approach was via transforaminal lumber interbody fusion (TLIF) with 87.8% performing at least one procedure in the previous year. In keeping with this, 24 surgeons (58.5%) had performed 11 to 50 cases in that time frame. Eighty-six percent had performed no lumbar artificial disc replacements over their last year of practice. There was clear consistency on the relevance of a patient specific management (73.2%) on the preferred fusion approach. The most preferred method was pedicle screw fixation (78%). The use of stand-alone cages was not supported by any respondents. With regards to the cage material, titanium cages were the most used (41.5%). Published clinical outcome data was the most important variable in dictating implant choice (87.8%). Cage thickness was considered the most important aspect of cage geometry and hyperlordotic cages were preferred at the lower lumbar levels. Autograft bone graft was most commonly preferred (61.0%). Amongst the synthetic options, DBX/DBM graft (64.1%) in injectable paste form (47.5%) was preferred. In conclusion, findings from this study are in partial agreement with previous work from the United Kingdom, but highlight the variance of practice within Canada and the need for large-scale clinical studies aimed to set specific guidelines for certain pathologies or patient categories

Introduction and Objective. Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) represent the most popular techniques in performing an interbody fusion amongst spine surgeons. Pseudarthrosis, cage migration, subsidence or infection can occur, with subsequent failed surgery, persistent pain and patient’ bad quality of life. The goal of revision fusion surgery is to correct any previous technical errors avoiding surgical complications. The most safe and effective way is to choose a naive approach to the disc. Therefore, the anterior approach represents a suitable technique as a salvage operation. The aim of this study is to underline the technical advantages of the anterior retroperitoneal approach as a salvage procedure in failed PLIF/TLIF analyzing a series of 32 consecutive patients. Materials and Methods. We performed a retrospective analysis of patients’ data in patients who underwent ALIF as a salvage procedure after failed PLIF/TLIF between April 2014 to December 2019. We recorded all peri-operative data. In all patients the index level was exposed with a minimally invasive anterior retroperitoneal approach. Results. Thirty-two patients (average age: 46.4 years, median age 46.5, ranging from 21 to 74 years hold- 16 male and 16 female) underwent salvage ALIF procedure after failed PLIF/TLIF were included in the study. A minimally invasive anterior retroperitoneal approach to the lumbar spine was performed in all patients. In 6 cases (18.7%) (2 infection and 4 pseudarthrosis after stand-alone IF) only anterior revision surgery was performed. A posterior approach was necessary in 26 cases (81.3%). In most of cases (26/32, 81%) the posterior instrumentation was overpowered by the anterior cage without a previous revision. Three (9%) intraoperative minor complications after anterior approach were recorded: 1 dural tear, 1 ALIF cage subsidence and 1 small peritoneal tear. None vascular injuries occurred. Most of patients (90.6%) experienced an improvement of their clinical condition and at the last follow-up no mechanical complication occurred. Conclusions. According to our results, we can suggest that a favourable clinical outcome can firstly depend from technical reasons an then from radiological results. The removal of the mobilized cage, the accurate endplate and disc space preparation and the cage implant eliminate the primary source of pain reducing significantly the axial pain, helping to realise an optimal bony surface for fusion and enhancing primary stability. The powerful disc distraction given by the anterior approach allows inserting large and lordotic cages improving the optimal segmental lordosis restoration

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

Introduction. Augmentation of spinal fusion using bone grafts is largely mediated by the osteoinductive potential of mesenchymal stem cells (MSC) that reside in cancellous bone. Iliac crest (IC) is a common autograft, but its use presents an increased risk for donor-site pain, morbidity and infection. Degenerative facet joints (FJ) harvested during facetectomy might servce as alternative local grafts. In this study, we conducted an intra-individual comparison of the osteogenic potential of MSC from both sources. Methods. IC and degenerative FJ were harvested from 8 consecutive patients undergoing transforaminal lumbar interbody fusion surgery for spinal stenosis. MSC were isolated by collagenase digestion, selected by plastic adherence and minimally expanded for downstream assays. Clonogenic and osteogenic potential was evaluated by colony formation assays in control and osteogenic culture medium. Osteogenic properties, including alkaline phosphatase (ALP) induction, matrix mineralization and type I collagen mRNA and protein expression were characterized using quantitative histochemical staining and reverse transcription PCR. Spontaneous adipogenesis was analysed by adipocyte enumeration and gene expression analysis of adipogenic markers. Results. Average colony-forming efficiency in osteogenic medium was equal between IC (38±12%) and FJ (36±11%). Osteogenic potential at the clonal level was 55±26 and 68±17% for IC and FJ MSC, respectively. Clonogenic and osteogenic potential were significantly negatively associated with donor age. Osteogenic differentiation led to significant induction of ALP activity in IC (6-fold) and FJ (8-fold) MSC. Matrix mineralization quantified by Alizarin red staining was increased by osteogenic differentiation, yet similar between both MSC sources. Protein expression of type I collagen was enhanced during osteogenesis and significantly greater in IC MSC. Correspondingly, COL1A2 mRNA expression was higher in osteogenically differentiated MSC from IC. Adipocyte numbers showed significant differences between IC (63±60) and FJ (18±15) MSC under osteogenic conditions. Negative (GREM1) and positive (FABP4) adipogenic markers were not differentially expressed between sources. Conclusion. MSC from IC and degenerative FJ largely display similar clonogenic and osteogenic properties in vitro. Differences at the molecular level are not likely to impair the osteoinductive capacity of FJ MSC. Facetectomy samples are viable bone autografts for intervertebral spinal fusion