We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage. Cite this article: Bone Joint J 2013;95-B:217–23

1. At the present stage of our experience, when 150 patients have been analysed over a period of five years, the conclusion has been reached that anterior interbody fusion in the lower lumbar spine is a procedure which should be added to our surgical armamentarium for use in selected cases. 2. Patients suffering from chronic intervertebral disc degeneration whose main symptoms are recurrent incapacitating backache derive the most benefit from this procedure. 3. When used as a salvage operation in patients who have had previous unsuccessful laminectomy or posterior fusion, good results can be expected. 4. In patients with spondylolisthesis anterior interbody fusion should be confined to cases in which the vertebral bodies have not slipped forward more than one-third

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

Introduction. Iatrogenic spondylolisthesis occurs infrequently after posterior decompression. Posterior surgery is challenging due to altered anatomy and scarring. Anterior lumbar interbody fusion (ALIF) allows indirect decompression, restoration of lordosis and fusion. Material and Methods. Retrospective review of 6 patients (5 female, 1 male, mean age 64±5.8 years) with iatrogenic spondylolisthesis (5 L4/L5; 1 L4/L5) treated with stand-alone ALIF (Synfix, BMP2). Assessment of pelvic incidence, listhesis, pre- and post-operative ODI, VAS, global lumbar lordosis and segmental lordosis as outcome measurements. Results. The slippage was grade II at L4/L5 in 3 patients and grade I in 2 patients at L4/L5 and 1 patient at L5/S1. Average ODI dropped from 49±11% pre-operatively to 30±9% at 6 and to 25±6% at 12 months follow-up. VAS average dropped from 7±1 to 3±1 at 6 and 12 months follow-up. Average pelvic incidence was 54.6±8.0°. Global lordosis of 44.6±5.2° increased to 49.0±8.6°; Segmental lordosis in L4/5 was increased from 12.1±8.2° to 22.4±3.7° at 6 and 20.5±7.9° at 12 months. Cage migration due to severe osteoporosis occurred in 1 case after 5 months. Conclusion. Anterior interbody fusion offers good stabilization and restoration of lordosis in iatrogenic spondylolisthesis. In our group, ODI and VAS scores were improved. These early results encourage further investigations regarding long-term follow-ups and prospective studies in larger patient groups

Introduction: The initial promise of stand-alone threaded anterior interbody fusion cages to treat chronic low back pain has not been maintained. In an attempt to overcome some of the problems associated with threaded fusion devices (endplate subsidence, failure to re-establish lordosis and displacement) a two-part ALIF cage was devised. The device consists of a rectangular frame that accommodates a threaded, open-weave cylinder holding bone graft material. The device addresses the biomechanical issues required for successful ALIF whilst providing a large area for bone in-growth and is a less invasive solution than a formal 3600 fusion. Methods: From August 2001 to December 2002, 41 patients who fulfilled selection criteria for a single or two-level 3600 spinal fusion for low back and leg symptoms underwent ALIF using Stabilis. All patients had failed to improve with all non-invasive and minimally invasive treatments available to them. Prospective follow-up has continued for all cases using the Low Back Outcome Score and a Patient Satisfaction Score. Plain x-rays were taken at 3, 6 and 12 months post-operatively and the 12-month series included flexion and extension films. Results: Ten patients (24.4%) have completed more than 12 months follow-up; 18 (43.9%) are between six and twelve months post surgery and the rest (31.7%) have less than six months follow-up. LBOS results for the first 10 showed 9 (90%) as excellent or good. LBOS results for the second group of 18 were excellent or good in 15 (83.3%). All but two of the 28 patients, would be prepared to undergo the procedure again and all would recommend the operation to a friend with similar trouble. Radiographic assessment at 6 months showed 16 patients had at least a partial anterior or posterior sentinel sign. Using motion criteria, all 10 cases at one year were fused on flexion and extension lateral x-rays. No devices migrated anteriorly or posteriorly and no lucent lines have been seen around the implants. Three of the two-level procedures showed some subsidence of the L4/5 implant into the L5 vertebral body, but none were symptomatic. No clear reasons have emerged to explain the clinical failure of 14% of the patients given the radiological success. In only one was there a mismatch in the LBOS outcome measure and the satisfaction rating. Conclusions: Stabilis is a useful standalone ALIF device that not only addresses the theoretical biomechanical failures of anterior threaded interbody fusion cages, but has been shown in this early clinical and radiological evaluation to be effective, objectively and subjectively. It is likely that in the medium term future, fewer patients will require fusion to treat back and leg pain as the results from lumbar spine arthroplasty become established and non-fusion technologies become accepted. Until that time, experience in the UK and USA suggests that Stabilis is a good alternative to 3600 fusion

INTRODUCTION: The initial promise of stand-alone threaded anterior interbody fusion cages to treat chronic low back pain has not been maintained. In an attempt to overcome some of the problems associated with threaded fusion devices (endplate subsidence, failure to re-establish lordosis and displacement) a two-part ALIF cage was devised. The device consists of a rectangular frame that accommodates a threaded, open-weave cylinder holding bone graft material. The device addresses the biomechanical issues required for successful ALIF whilst providing a large area for bone in-growth and is a less invasive solution than a formal 360° fusion. METHODS: From August 2001 to December 2002, 41 patients who fulfilled selection criteria for a single or two-level 360° spinal fusion for low back and leg symptoms underwent ALIF using Stabilis. All patients had failed to improve with all non-invasive and minimally invasive treatments available to them. Prospective follow-up has continued for all cases using the Low Back Outcome Score and a Patient Satisfaction Score. Plain X-rays were taken at three, six and 12 months post-operatively and the 12-month series included flexion and extension films. RESULTS: Ten patients (24.4%) have completed more than 12 months follow-up; 18 (43.9%) are between six and twelve months post surgery and the rest (31.7%) have less than six months follow-up. LBOS results for the first 10 showed nine (90%) as excellent or good. LBOS results for the second group of 18 were excellent or good in 15 (83.3%). All but two of the 28 patients, would be prepared to undergo the procedure again and all would recommend the operation to a friend with similar trouble. Radiographic assessment at six months showed 16 patients had at least a partial anterior or posterior sentinel sign. Using motion criteria, all 10 cases at one year were fused on flexion and extension lateral X-rays. No devices migrated anteriorly or posteriorly and no lucent lines have been seen around the implants. Three of the two-level procedures showed some subsidence of the L4/5 implant into the L5 vertebral body, but none was symptomatic. No clear reasons have emerged to explain the clinical failure of 14% of the patients given the radiological success. In only one was there a mismatch in the LBOS outcome measure and the satisfaction rating. CONCLUSIONS: Stabilis is a useful stand-alone ALIF device that not only addresses the theoretical biomechanical failures of anterior threaded interbody fusion cages, but has been shown in this early clinical and radiological evaluation to be effective, objectively and subjectively. It is likely that in the medium term future, fewer patients will require fusion to treat back and leg pain as the results from lumbar spine arthroplasty become established and non-fusion technologies become accepted. Until that time, experience in the UK and USA suggests that Stabilis is a good alternative to 360° fusion

From April 2001 to January 2003, 60 patients were selected for a circumferential fusion with an ALIF Brantigan cage and posterior titanium instrumentation. The aim of this study was to analyse the complications and the effects of circumferential fusion on functional outcome and lumbar lordosis. Circumferential fusion restored lordosis, provided a higher fusion rate, and showed a tendency towards better functional outcome and reduced back and leg pain.

Aim: To determine the incidence of adjacent level osteophytes in patients who have had anterior cervical fusion using an anterior cervical plate as compared to those who are fused without an anterior cervical plate. Design: We retrospectively reviewed the lateral radiograms of sixty two patients who have had an anterior cervical fusion with a minimum follow up of twelve months. Materials and methods: We looked for the development of adjacent level osteophytes in these patients at their final follow up, which was generally at the time radiological fusion. There were 27 patients in the first group who had an anterior cervical plate used to fix the vertebrae in addition to the Cervios cage, while the 35 patients in the second group in whom only a Rabea cage was used for the fusion. The mean follow-up was 20.6 months (range 12–48). Results: 64.3% of the patients who had an anterior cervical plate developed adjacent level osteophytes while none of the patients who have had the fusion without the cage developed the osteophytes. Conclusion: We found the patients who had an anterior cervical interbody fusion using a plate had a significant risk of developing adjacent level osteophytes while this is not seen in patients who do not have the plate for the fixation

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.

Spines are often stabilised posteriorly by internal fixation and anteriorly by a bone graft. The effect of an autologous bone graft from the iliac crest on implant loads is unknown. We used an internal spinal fixation device with telemetry to measure implant loads for several body positions and activities in nine patients before and after anterior interbody fusion. With the body upright, implant loads were often higher after than before fusion using a bone graft. Distraction of the bridged region led to high implant loads in patients with a fractured vertebra and to marked changes in load in those with degenerative instability. Leaving the lower of the bridged intervertebral discs intact led to only small changes in fixator load after anterior interbody fusion. A bone graft alone does not guarantee a reduction of implant loads

Purpose: To investigate the potential value of titanium anterior interbody cages compared to morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction and fusion for Scheuermann’s kyphosis. Methods and Materials: A Non-Randomised historic cohort study of two surgical techniques in matched subjects was carried out.15 patients with identical pre-operative radiographic and physical variables (age, gender, height, weight, BMI ) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction and fusion . Group A (n=8) had morsilized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. Pre- and post-operative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson’s angle(FA) , Voutsinas index(VI), Sagittal Vertical Axis (SVA), Sacral Inclination (SI) and Lumbar Lordosis (LL). Interbody Fusion was assessed at final follow up. Each patient was reviewed at 3, 6, 12, 24, 48 and 60 months following surgery with standing radiographs. Wilcoxon-matched pairs test and Mann-Whit-ney test were used for statistical analysis. Results: The average follow-up for groups A was 70 and Group B,66 months. For the whole group, the pre-operative : postoperative median Cobb angle, FA, VI, SVA and SI were 86: 42degrees, 50 : 28.4degrees, 28.7 :13, −3.5 : −4.0 centimetres and 40 : 34 degrees respectively. There were significant differences for all variables [p< 0.01] indicating good correction. At four-year follow-up, fusion criteria were satisfied in 12 / 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference with respect to the variables between the two groups and both retained the post-operative correction achieved. Conclusion: There was no significant advantage in the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann’s Kyphosis

Persistent back pain in the presence of an intact posterior fusion is commonly seen and is often regarded as being psychogenic in origin. This paper discusses five patients, all of whom were chronically disabled by such pain; all five had a confirmed posterior and/or lateral fusion. In each case lateral discography identified the disc within the fused segment as the source of symptoms and pain relief was obtained with an anterior interbody fusion. This source of pain should be considered as a possibility in similar cases of failed back surgery

A series of 123 patients suffering traumatic spondylolisthesis of the axis is reported. This lesion is associated with extension and axial loading injury, and there is a high incidence of injuries of the face or scalp and of associated fractures of the upper cervical spine. There is a low incidence of neurological injury, which seems paradoxical in the presence of what appears to be gross instability, but protection from extremes of flexion and extension may be adequate treatment. Union is usual regardless of displacement. Traction is a safe means of treatment, but early waking in a halo support reduces time in hospital without jeopardizing the result. Operation is needed only for chronic instability with or without pain, and anterior interbody fusion of C2--3 is than preferred in order to preserve rotation at the atlanto-axial joints

We present a study of 30 fusion operations in 26 rheumatoid arthritics with cervical spine instability. Atlanto-axial instability was present in 15, of whom 12 were fused; three had cord involvement and all made a partial or complete recovery following fusion. Cranial settling necessitated cranio-cervical fusion in four patients; all fused, and one with myelopathy was relieved. Subaxial instability required fusion in seven cases; two postoperative deaths followed the only two anterior interbody fusions. Posterior fusion was successful in the other five, with remission of neurological compromise in the three with myelopathy and one with radiculopathy. We conclude that neurological compromise in an unstable but mobile rheumatoid cervical spine can usually be brought to remission by immobilisation alone, so decompressive procedures are unnecessary in the first instance

Operative treatment was performed in nine patients with cervical spondylotic myelopathy complicating athetoid cerebral palsy. The first two patients were treated by laminectomy, and the other seven by anterior interbody fusion. The symptoms in both the laminectomy patients improved after operation, but became worse again when cervical instability developed; they then had to have an anterior fusion in addition. In six of the seven patients who had primary anterior fusion a halo-cast (or a halo-vest) was used to keep the cervical spine immobile, and good bony fusion was obtained with satisfactory results. However, in one patient no halo apparatus was used, bony union did not occur and the radiculopathy reappeared. In cervical myelopathy complicating athetoid cerebral palsy laminectomy is contra-indicated; anterior fusion combined with a halo apparatus is, however, satisfactory

1. Anterior transperitoneal lumbar fusion is a successful method of stabilising painful mechanical derangements which have not responded to the usual conservative measures. 2. The operation in this series was done mainly for backache; it should not be contemplated if there is definite evidence of nerve root compression, because sequestrated disc material cannot be removed from the spinal canal from the anterior route. 3. Careful technique has resulted in few complications attributable to the operation. 4. This method is sometimes thought to be inapplicable in cases of spondylolisthesis with a displacement of more than one-third. However, in this series we have seen the block type of graft used with a good measure of clinical and radiological success. 5. There is no doubt that for those patients who have had previous unsuccessful laminectomies or posterior fusions anterior interbody fusion offers an excellent prospect of recovery

It has been thought that lumbar intervertebral discs were innervated segmentally. We have previously shown that the L5-L6 intervertebral disc in the rat is innervated bilaterally from the L1 and L2 dorsal root ganglia through the paravertebral sympathetic trunks, but the pathways between the disc and the paravertebral sympathetic trunks were unknown. We have now studied the spines of 17 rats to elucidate the exact pathways. We examined serial sections of the lumbar spine using immunohistochemistry for calcitonin gene-related peptide, a sensory nerve marker. We showed that these nerve fibres from the intervertebral disc ran through the sinuvertebral nerve into the rami communicantes, not into the corresponding segmental spinal nerve. In the rat, sensory information from the lumbar intervertebral discs is conducted through rami communicantes. If this innervation pattern applies to man, simple decompression of the corresponding nerve root will not relieve discogenic pain. Anterior interbody fusion, with the denervation of rami communicantes, may be effective for such low back pain

Between 1978 and 1988 a total of 27 operations were performed on 26 patients for cervical myelopathy due to rheumatoid disease in the subaxial spine. Three different causes were recognised: the first group had cord compression due to subluxation of the cervical spine itself (6 patients); the second had cord compression occurring from in front, with rheumatoid lesions of vertebral bodies or discs (6); the third had compression from behind the cord due to granulation tissue within the epidural space (14). Group I was treated by closed reduction of the subluxation followed by surgical fusion either from in front or behind. Group II was decompressed by subtotal resection of the involved vertebral bodies and discs, followed by interbody fusion. The patients in group III were decompressed by laminectomy and excision of fibrous granulation tissue from the epidural space. Good recovery of neurological function was observed after 18 of the operations, fair recovery after five, poor recovery followed three, and one was worse. Myelopathy recurred in four patients, all of whom had had anterior interbody fusion

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

Introduction and Aims: Trans-laminar screw fixation is a popular method of posterior stabilisation when performing a 360-degree lumbar fusion, but many have concerns over the biomechanical stability of this construct. The objective of this paper is to compare the fusion rate and clinical outcome of this method with pedicle screw fixation. Method: During 2001, 31 patients underwent combined anterior and posterior fusion by the two senior surgeons for the treatment of discogenic low back pain. Anterior interbody fusion was performed using the Syncage LR in all patients. Sixteen patients underwent trans-laminar screw fixation posteriorly and 15 underwent pedicle screw fixation. Fusion was assessed by fine cut CT scan at one year post-operatively. Function was assessed with pre- and post-operative Low Back Outcome Score and visual analogue pain scores. Results: The average follow-up was 15.5 months. The incidence of pseudarthrosis in the trans-laminar screw group was approximately 80% (15 out of 19 levels), compared to 20% (4 of 21 levels) in the pedicle screw group (p < 0.05). There were trends towards greater improvements in the LBOS and VAS scores in the pedicle screw group. There were two surgical complications in the trans-laminar screw group and one in the pedicle screw group. Conclusion: The use of trans-laminar screws is associated with a significantly higher rate of pseudarthrosis compared to pedicle screw fixation. Assessing fusion with fine cut CT scans has revealed a higher rate of pseudarthrosis with trans-laminar screw fixation than has previously been reported