To assess the effectiveness of dynamic stabilisation as a treatment for discogenic pain compared to standard treatment of interbody fusion. All patients were referred for a 2 year back-pain management programme. Patients with continued pain following conservative treatment underwent discography & MRI. Patients with painful degenerate discs on the above investigations were selected. Patients underwent interbody fusion (PLIF/TLIF) or dynamic stabilisation. Mean follow-up was 24 months with a minimum follow-up of 12 months. All patients had pre-operative ODI and VAS scores. Patients were then sent further questionnaires at 6 month intervals. The mean improvement in ODI following dynamic stabilisation was 20% (-20% → 56%), the mean improvement in the pain score was 2.4 (0→8). The mean improvement in ODI following interbody fusion was 11% (-14%→48%), the mean improvement in the pain score was 2.6 (-4→9). 10 patients in the dynamic stabilisation group had a greater than 20% improvement in ODI, 7 patients in the interbody fusion group had similar results. The above results demonstrate that dynamic stabilisation is at least as effective at treating discogenic pain as interbody fusion. The results however do question the validity of either interbody fusion (PLIF/TLIF) or dynamic stabilisation in the management of discogenic pain

Objective. To assess the effectiveness of dynamic stabilisation as a treatment for discogenic pain compared to standard treatment of interbody fusion. Study Design & Subjects. All patients were referred for a 2 year back-pain management programme. Patients with continued pain following conservative treatment underwent discography & MRI. Patients with painful degenerate discs on the above investigations were selected. Patients underwent interbody fusion (PLIF/TLIF) or dynamic stabilisation. Mean follow-up was 24 months with a minimum follow-up of 12 months. Outcome Measures. All patients had pre-operative ODI and VAS scores. Patients were then sent further questionnaires at 6 month intervals. Results. The mean improvement in ODI following dynamic stabilisation was 20% (-20% → 56%), the mean improvement in the pain score was 2.4 (0→8). The mean improvement in ODI following interbody fusion was 11% (-14%→48%), the mean improvement in the pain score was 2.6 (-4→9). 10 patients in the dynamic stabilisation group had a greater than 20% improvement in ODI, 7 patients in the interbody fusion group had similar results. Conclusion. The above results demonstrate that dynamic stabilisation is at least as effective at treating discogenic pain as interbody fusion. The results however do question the validity of either interbody fusion (PLIF/TLIF) or dynamic stabilisation in the management of discogenic pain

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

Anterior decompression and adequate spine fixation in patients with cervical radiculopathy and myelopathy are essential for functional restoration of cervical spine. In this study, we performed evaluation and comparative radiological assessment of several types of spinal implants in terms of bone block formation, sagittal alignment and effectiveness as a structural support. Materials and Methods: From 1993 to 2003, 165 patients with radiculopathy and myelopathy due to degenerative disease of cervical spine were operated on. The age of patients was 32–74 years (mean age 57, 8). The interbody fusion was performed by several methods. Group1. Autograft – 91 patients. Group 2. TiNi alloy cages – 74 patients. Group 3. Varilift expandable cages without plate fixation – 22 patients. Group 4. Verilift cages with plate fixation – 8 patients. Group 5. Bone substitute spacer and plate fixation – 3 patients. Results: In groups 1 and 2, the bone and bone-metal block was formed during the first 3–4 months after surgery in all patients. There were no cases of bone resorbtion around the TiNi cages or loosening of the device. In patients with one-level (15 patients) interbody fusion by Varilift cages (group 3); formation of the bone block during the same time period was observed in 14 out of 15 patients. In cases with two-level fusion (7 patients), the bone block at the second level was not formed for longer than 6 months. There were 7 cases of subsiding and segmental kyphosis. In group 4, we did not detect any cases of loosening, subsiding or segmental kyphosis. In group 5, no bone block formation was observed after 6 months despite plate fixation. Conclusions: A high fusion rate was achieved after a single or multi-level discectomy and interbody fusion by autograft and TiNi cages, which did not subside due to their design and superelasticity and can therefore be used without plate fixation. Varilift cages were also very effective, but if used without plate fixation may be associated with subsiding effect. The use of the bone substitute spacer is questionable in cervical spine surgery. Cervical plate fixation is effective as a prophylactic measure against segmental kyphosis in all types of interbody fusion

Purpose: Interbody fusion cages have met with great success as an adjunct in the treatment of painful degenerative disc disease. One of the limitations is the need for the use of autogenous cancellous bone graft. In preclinical studies recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered in a variety of carriers has been shown to be an effective substitute for autogenous bone, resulting in more rapid and reliable healing than that seen in control groups. The goal of this study was to report the early results of the first human trial attempting to use rhBMP-2 in interbody fusion cages. Methods: This study was an FDA approved IDE multicenter pilot study. From 1/97 to 4/97, 14 patients were entered into a prospective, randomized trial. All patients had single level lumbar degenerative disc disease that was refractory to prolonged nonoperative care and were candidates for anterior interbody fusion of L4-5 or L5-S1. After consent, patients were randomized to either the control group (N-3) and received autogenous bone inside tapered titanium fusion cages (NOVUS LT, Sofamor Danek Memphis, TN) or to the investigational group (N = 11) and received rhBMP-2 (1.5 mg/ml)(Genetics Institute, Cambridge MA) delivered in a collagen sponge (Helistat, Integra Life Sciences, Plainsboro, NJ) inside the fusion cages. Depending on the size, the sponge in each cage was soaked with from 1.3 to 2.6 ml of the rhBMP2 solution. Patients were followed at regular intervals with plain x-ray, CT scan with reconstruction, and a full panel of blood tests. Radiographs were reviewed by an independent blinded radiologist with fusion defined as < 5 degrees of sagittal motion, absence of radiolucent lines, and presence of continuous bone through the cages. Clinical results were assessed using an outcomes questionnaire including the SF-36 general health status and Oswestry low back specific instruments. Results: All 14 patients were available for 1-year follow-up. No cages displaced and no further surgeries were required. Mean hospital stay was 2.0 days for the rhBMP-2 patients compared to 3.3 days for the autograft controls. Of the 11 rhBMP2 patients, 10 of 11 were judged to be fused at 3 months. At 6 months and 1-year all 11 rhBMP-2 patients were noted to have a solid arthrodesis. Of the 3 control patients, 2 had solid arthodesis and one had an apparent nonunion at 1 year. On sagittal CT scan reconstruction new bone growth was seen throughout and anterior to the cages that were filled with rhBMP-2. No patients had bone formation outside of the desired area. The control patient with the nonunion had a halo surrounding the cage on the sagittal CT reconstruction. This patient had persistence of low back pain. Compared to preop, the Oswestry scores at 3 months were decreased in the rhBMP-2 group (39 to 30) compared to controls which were increased (35 to 43) and both mean scores were similar at 6 months (28 and 27). Conclusion: The preliminary results from this clinical trial with rhBMP-2 inside interbody fusion cages were excellent and support a larger pivotal trial. The arthrodesis was found to occur more rapidly and reliably than in the controls, although the sample size was limited. In addition to faster bone healing, a major advantage was the elimination of bone graft donor site morbidity and realization of decreased hospital stay. No evidence of excessive bone formation or systemic complications occurred. Moreover, this study provides one of the first demonstrations of consistent and unequivocal osteoinduction by a recombinant growth factor in humans

Introduction Anterior column reconstruction and fusion remains the gold standard of treatment for a number of spinal pathologies. One of the challenges of interbody fusions cages is the footprint of the cage reducing the surface area of endplate available for fusion. Biodegradable polymer implants will over time present a greater area for fusion and may help to reduce problems such as stress shielding, particulate debris and retained foreign body response. Resorbable cages have been have been prepared from a number of different materials, including inorganic composites (eg hydroxyapatite / tricalcium phosphate) and polymers (Poly L-lactide-co-D,L-lactide (PDLLA)). However all of the current options for interbody fusion have reported deficiencies or complications. The synthesis, mechanical properties, and degradation behaviour of two novel biopolymers are presented and the applicability for use as materials in interbody fusion devices is discussed. Methods Methacrylated adipic anhydride (MAA) and methacrylated sebacic anhydride (MSA) pre-polymers were synthesized by melt condensation. Conversion of the acid to the anhydride was confirmed using 1H nuclear magnetic resonance (NMR) (Bruker, Alexandria, NSW) and FT- Infrared spectroscopy (Nicolet, Waltham MA). These pre-polymers were subsequently co-polymerized with methyl methacrylate (MMA) and 0.25 wt% benzoyl peroxide at 65oC for 16hrs and post-cured at 120oC under vacuum for 2 hrs to form biodegradable networks. The co-polymerization behaviour was monitored by FT-Raman spectroscopy. The compressive mechanical properties of the polymer were determined using an Instron 5567 (Bayswater Vic.). The polymer networks were degraded in phosphate buffered saline (PBS) with various amounts of MAA and MSA. Results The formation of the pre-polymer was confirmed with the observation of NMR peaks at 5.8 and 6.2 ppm and FT-IR peaks at 1637cm-1. Copolymerization was followed with consecutive FT-IR acquisitions with 100% conversion achieved between 10 and 30 hrs depending on the ratio of MMA to MSA or MAA. Increasing the fraction of methacrylated anhydride slowed the reaction rate. The compressive strength of the MAA and MSA based copolymers was measured as a function of anhydride concentration. Compressive strength for MMA increased (90±9 to 140±10 Mpa) in an approximately linear manner for MAA concentrations from 10 to 40 wt.% but decreased markedly for MAA concentration of 45% (62±14 Mpa). The compressive strength of MSA decreased exponentially for concentrations ranging from 10 to 45 wt.% (140±18 to 39±1 Mpa). Discussion The use of poly-L-lactic acid in lumbar interbody cages has been shown to be mechanically feasible with the mechanical strength of the cage material reported to be 93 Mpa (. 1. ). The material described here has controlled mechanical properties in the required range as well as a degradation behaviour that lends itself better to spinal applications than current materials

The purpose of the study was to determine the effectiveness of rhBMP-2 when applied to an absorbable collagen sponge for interbody fusion with allograft spacers. Seventy-seven consecutive patients requiring inter-body fusion with one hundred and eighteen levels were included in the study. In thirty-six patients cervical or lumbar interbody fusions were performed using allograft and rhBMP-2. In the remaing allograft was used with demineralised bone matrix. In patients undergoing anterior cervical decompression and fusion (ALIF) machined allograft spacers were supplemented with anterior locking plates. In those scheduled for anterior lumbar inter-body fusion (ALIF) or transforaminal lumbar interbody fusion (TLIF), machined allograft spacers were supplemented with posterior pedicle screw constructs. There were no stand alone ALIF procedures. All patients undergoing surgery were assessed preoperatively and at two weeks, six weeks, three, six, twelve, twenty-four months following surgery.Their Oswestry disability index (ODI) questionaires, Visual analogue scale (VAS) scores and a pain diagram were recorded. Radiographic measurements were made on the electronic public access computer system (EPACS). All patients with allograft plus rhBMP-2 showed radiographic evidence of fusion by six months following surgery. The allograft with demineralised bone matrix group took considerably longer to achieve the same radiographic end plate appearance. Subsidence was obvious on radiographs in greater than 50% of cases with allograft and rhBMP-2 at three months. It was noted to occur between six weeks and three months and there was no significant subsidence after six months. This was statistically significant with a p< 0.0001 (fisher exact test). The average subsidence for the entire rhBMP-2 group at twelve months was 16.5%(SE 2.5% and range 0–58%) and for the allograft and bone matrix group was 4.6%(SE.74% range 0–15%)with a p< 0.0001 (independant t test). Although high rates of fusion can be accomplished with allograft and rhBMP-2 (100%), significant subsidence occurs in greater than 50% of lumbar spine cases and 30% of cervical spine cases. This is possibly a result of early bone turnover with loss of structural support of the allograft spacer and end plate resorption

RhBMP2 was used in thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF) using anterior cervical locking plates and lumbar posterior pedicle screw constructs. All patients showed radiographic fusion at six months. Early lucency, subsidence, and increased pain occurred between six weeks and three months in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% in ALIFS, 24% in TLIFS, and 53% in ACDF. Pain improved by the sixth month. We recommend alternative structural support when using RhBMP2. To determine effectiveness of RhBMP2 in interbody fusion with machined allograft spacers (MTF Synthes Spine USA femoral ring, TLIF and fibular ring cervical spacers). A prospective study of thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF). Machined allograft spacers and RhBmp2 were supplemented with anterior locking plates in the cervical spine while the lumbar segments were supplemented posterior pedicle screws constructs. Patients were followed at two weeks, six weeks, three months, six months, one year. Patients were examined, had xrays, completed Oswestry scores, pain diagrams, and VAS for pain preoperatively and at every follow up appointment. All the patients showed radiographic evidence of fusion at six months after surgery. Early lucency and subsidence of allografts was observed in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% (range13–42%) in ALIFS, 24% in TLIFS (range 13–40%), and 53% in ACDF. Subsidence and reporting of increased pain occurred between the six- week and three month follow up after which patients improved. Although high rates of early fusion can be accomplished with allograft spacers and rhBMP2 significant subsidence occurs in greater than 50% of lumbar cases and 30% of cervical cases due to early turnover and loss of structural support of the allograft. We recommend alternative structural support when using RhBMP2

The management of discogenic pain continues to be controversial. The results for operative and non-operative management are variable. This study aims to look at the results of interbody fusion versus dynamic stabilisation in patients with discogenic pain. Diagnosis was made by use of MRI and provocative discography. All patients had pre-operative Visual Analogue Scores and Oswestry Disability Index scores. Patients were then assessed in the post-operative period at 6 months, 1 year and 2 years. Case matched series with 19 patients in each group with a mean follow-up of 24 months. In comparison of both techniques there were no statistically significant differences but the dynamic stabilisation group had improved outcomes with both measures. The results did raise some further issues, as several patients in each group were either worse or had no significant improvement following surgery. In conclusion this paper raises concerns regarding the use of surgery for patients with discogenic pain. If surgery is however considered, dynamic stabilisation is a valid alternative to interbody fusion

Objective: To determine if a porous, coralline-derived hydroxyapatite block (ProOsteon 500. TM. , Interpore, Irvine, CA) is a suitable substitute for tricortical iliac crest autograft in cervical interbody fusion. Design: A prospective randomised trial with two-year follow-up comparing clinical and radiographic outcomes in patients receiving either iliac crest or hydroxyapatite grafts in cervical interbody fusion. Subjects: Twenty-nine patients undergoing cervical fusion and anterior plating were randomised to receive either iliac crest (Group I) or hydroxyapatite (Group II) interbody grafts. Fourteen patients (19 grafts) in Group I and twelve patients (18 grafts) in Group II were available for final analysis. Both groups were similar with respect to age, sex, diagnosis and levels fused. Outcome Measures: The SF-36 and Oswestry Disability Index were used to measure clinical outcome. Post-op and final follow-up radiographs were analysed for graft fragmentation, loss of height, loss of angular alignment and hardware failure to assess structural integrity of the graft. Computed or plain tomography was used to evaluate fusion. Results: Groups I and II demonstrated improvement in preoperative scores for bodily pain (p=. 016 and. 016 respectively) and physical functioning (p=. 050 and. 016 respectively) at final follow-up. There was no significant difference in SF-36 and Oswestry scores between the two groups. Successful radiographic fusion was similar in both groups (79% in Group I and 76% in Group II). Graft fragmentation occurred in 89% of the hydroxyapatite grafts and 11% of the autografts (p=. 001). Greater than 2mm of graft height and 3° of segmental lordosis were lost in 55% of hydroxyapatite grafts vs. 11% of autografts (p=. 009). One patient in Group II and none in Group I required revision surgery for graft failure. The high rate of early radiographic failure in the hydroxyapatite grafts prompted suspension of further enrolment in the clinical trial. Conclusions: ProOsteon 500 coralline hydroxyapatite blocks do not possess adequate structural integrity to resist axial loading and maintain disc height or segmental lordosis during cervical interbody fusion

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

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

Since total disc replacement (TDR) has broadened the spectrum of surgical treatment of degenerative spine diseases many comparison studies, particularly with interbody fusions (IF), have been done. Even though comparable results concerning functionality, radiologic results and subjective rating of life-quality have been presented, very few data about athletic activity before and after spine surgery exists. Material and Methods: Between 1/2002 and 10/2006 181 patients had interbody fusions and 57 had a total disc replacement. Of 86 IF-patients and 25 patients with TDR we have complete data, which was collected in pre- and postoperative clinic and radiologic routine control with standardised questionnaires containing evaluation of level (frequency) and sort of sport. Patients are matched according to demographic data and preoperative activity beside the most important match of operation method. Results: Patients with Total disc replacement show a later resumption of sports (19 weeks) than fusion patients (14 weeks), but more TDR patients (60%) achieve their preoperative level of sport than IF-patients (36%) do. Vice versa to the Fusion group in the TDR group more patients start a new sport after surgery than to stop one. Percentage of patients doing sports post- compared to preoperative is higher in both groups. Less patients having a TDR complain about technical limitations during practicing sports than fusion patients. Discussion: Despite later resumption of athletic activity TDR seems to be the better surgical treatment of degenerative disc diseases in active patients and athletes due to overall higher sports levels. If long term results can keep up with short time follow ups has to be questioned

Introduction. Recently published results suggest insertion of shorter screws in L5/S1 stand-alone anterior interbody fusion, fearing S1 nerve root violation. However, insertion of shorter screws led to screw fixation failure and new onset of S1 body fractures. Material and Methods. Retrospective review of patients with L5/S1 stand-alone anterior interbody fusion, focussing on screw length, radiological outcomes (especially metal work failure, screw fixation and S1 body fractures) and new onset of S1 nerve root irritation. Results. 38 patients were included (mean age 46.2±13.3 years, 21 females, 17 males). Fusion of the L5/S1 segment was performed in between 2003-2010; postoperative follow-up ranged from 2-24 months. 15 patients had multilevel surgery (7 multiple segmental fusion, 8 hybrid procedures). Screw length ranged from 20-30 mm. No patient had new postoperative S1 nerve root irritation. Interestingly, 2 patients out of the hybrid group had a new onset of L5 radiculopathy, concordant to the level of disc-replacement. Follow-up x-ray review showed no fracture of S1 body fractures in all patients. No evidence of screw loosening, migration or metal work failure was reported. Conclusion. In our opinion, this review showed that insertion of longer screws for stand-alone anterior interbody fusion in L5/S1 is safe. Longer screws offer better stabilization and seem to minimize risks like S1 body fractures. Short and long-term follow-ups were satisfactory regarding screw placement, migration and positioning of implants in all patients

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

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

Aims: Presentation and evaluation of clinical outcomes of patients with cervical degenerative disc disease treated by Smith – Robinson method with interbody fusion by Cornerstone Carbon Cage (CCS) in own clinical experience. Methods: We operated 37 patients by anterior cervical discectomy with interbody stabilisation by CCS in the last 11 months. 31 patients were operated for the first time. In 6 cases, patients were reoperated after surgical treatment in other hospitals. The Smith – Robinson cervical discectomy with anterior interbody fusion by CCS was performed in all patients. Additionally, in 12 patients titan cervical plates were used. Follow-up examinations were performed in 2 and 6 months after the treatment. Results: All treated patients experienced total pain termination. In patients with posttraumatical discopathy and heavy cervical spondylosis with ligamental instability (33% all patients) additional internal stabilisation by cervical plate was performed. Neurological or local long-term postoperative complications were not observed. Conclusions: Patients who underwent treatment by anterior cervical discectomy met. S-R with interbody stabilisation by CCS benefited from the treatment and present good clinical outcome with pain termination and gradual disappearance of neurological disabilities. Using of cornerstone carbon cage allows to obtain good stabilisation without the necessity of allogenic bone graft insertion. This kind of stabilisation is sufficient without external collar stabilisation

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: The radiographic criteria for successful lumbar arthrodesis remains controversial. Plain radiographs including flexion-extension views are commonly used to assess fusion, but there is disagreement on the degree of apparent motion that is significant. Helical CT assessment of bridging bone between vertebrae is considered to be the most accurate method currently available. This study compared the use of plain radiographs including flexion-extension views with helical CT scans in the assessment of lumbar interbody fusion. Methods: Plain radiographs (including flexion-extension views) and helical CT scans were performed on 32 patients (47 levels) five years after ALIF using carbon fibre cages and autologous bone. A radiologist assessed fusion utilising the Hutter method to detect movement, whilst a spinal surgeon measured movement in degrees using the Simmons method. Helical CT scans (with sagittal and coronal reformatting) were assessed for the presence of bridging trabecular bone. Results: The radiographic fusion rate was 85% based on the presence of bridging bone, and also 85% with the Hutter method. The fusion rate was 74% when movement of at least two degrees was considered significant, but was 98% with the five degrees cut off adopted by the FDA. Fusion as determined by the presence of bridging trabeculae on helical CT Scans occurred in 67%. Concordance rates were as follows: between plain films and helical CT, 69.5%; between Hutter method and plain films, 76%; between Simmon’s method (two degrees) and helical CT, 67%; and between Simmon’s method with the FDA cut-off of five degrees and CT, 65%. Discussion: The assessment of fusion with radiographs appears to be unreliable. The use of plain films and flexion-extension radiographs clearly overestimated the actual fusion rates. Furthermore, there was low concordance between these methods and the more reliable helical CT. This disparity between fusion rates from radiographs and with helical CT supports the view that plain radiographs, including flexion-extension films are of limited value in the assessment of spinal arthrodesis

Study Design. A retrospective clinical study was conducted. Objectives. To evaluate the clinical and radiologic outcomes of one-stage posterior decompression-stabilization after partial reduction and trans-sacral interbody fusion with a titanium cage for severe L5–S1 spondylolisthesis. Summary of the Background Data. Trans-sacral inter-body fusion for the management of severe L5–S1 spondylolisthesis with or without partial reduction and pedicular fixation has been previously described. The use of a transsacral titanium cage has not been previously reported. Methods. Thirty-two patients with severe L5–S1 spondylolisthesis were treated consecutively with posterior decompression, partial reduction, pedicular fixation, and posterior lumbar interbody fusion using a trans-sacral titanium cage. The mean age at the time of surgery was 24.6 years (range, 11–55 years). The mean follow-up period was 48.3 months (range, 12–102 months). Twenty-three patients had severe back pain and twenty-five patients radicular pain. Nine patients had a partial unilateral L5 motor deficit and twenty-one an L5 sensory deficit. Twelve patients had extremely tight hamstrings. The mean preoperative percentage of slipping was 71.7% (range, 52–91%). Patients were evaluated for complications and fusions, and outcomes were collected using the modified Scoliosis Research Society Outcomes Instrument. Results. At follow-up, all patients, except one with major vascular complications, were extremely or reasonably satisfied with the surgery. All patients showed improvements in radiologic indexes and stable fusion at the final follow-up examination. Conclusions. Posterior decompression and partial reduction followed by circumferential stabilization performed in one stage combining pedicle fixation with trans-sacral titanium cage interbody fusion is an effective and safe technique for the management of severe spondylolisthesis