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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anterior lumbar interbody arthrodesis is commonly performed for conditions involving infection, deformity, and instability. The purpose of this investigation was to determine the effective dose of recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute inside a titanium threaded interbody fusion cage using a nonhuman primate model of laparoscopic anterior lumbar interbody arthrodesis. Eight adult rhesus monkeys underwent laparoscopic exposure of the lumbosacral spine followed by insertion of a hollow titanium threaded cylindrical cage (Sofamor-Danek, Memphis, TN, U.S.A.). Before insertion, the chamber of the cage was filled with a collagen sponge delivery vehicle soaked with either 0 mg/ml (sham, buffer only), 0.75 mg/ml (low dose), or 1.5 mg/ml (high dose) of rhBMP-2 (Genetics Institute, Cambridge, MA, U.S.A.). Fusions were evaluated in a blinded fashion with plain radiographs and computed tomography (CT) scans 12 and 24 weeks after surgery, and by manual palpation and histology after euthanasia 24 weeks after surgery. All five monkeys treated with a cage filled with rhBMP-2 obtained a solid fusion as assessed by manual palpation. The two monkeys that received no growth factor did not achieve solid fusions. Plain radiographs were of limited value, with fusions best assessed on sagittally reconstructed CT scans. Scans from the two animals treated without growth factor showed ingrowth of bone only into the outer edges of the cage, but not through the center. Scans from the rhBMP-2-treated animals demonstrated arthrodesis with continuous bone growth through the cage. Histologic analysis demonstrated normal mature trabecular bone surrounding and growing through the cages, which correlated with the CT scan findings. We conclude that rhBMP-2 delivered in a threaded titanium interbody cage can serve as a bone graft substitute in a nonhuman primate model. Sagittal reconstructed CT may be a better method to assess for fusion with this device.
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PMID:Laparoscopic anterior spinal arthrodesis with rhBMP-2 in a titanium interbody threaded cage. 958 64

The immediate stabilization provided by anterior interbody cage fixation is often questioned. Therefore, the role of supplementary posterior fixation, particularly minimally invasive techniques such as translaminar screws, is relevant. The purpose of this biomechanical study was to determine the immediate three-dimensional flexibility of the lumbar spine, using six human cadaveric functional spinal units, in four different conditions: (1) intact, (2) fixed with translaminar screws (TLS), (3) instrumented with anterior interbody cage insertion with the BAK system and (4) instrumented with BAK cage with additional TLS fixation. Flexibility was determined in each testing condition by measuring the vertebral motions under applied pure moments (i.e. flexion-extension, bilateral axial rotation, bilateral lateral bending) in an unconstrained manner. Anterior fixation with the BAK alone provided significant stability in flexion and lateral bending. Additional posterior TLS significantly reduced the motion in extension and axial rotation. TLS fixation alone resulted in smaller rotations than BAK fixation in all loading directions. Based on these results, it seems that interbody cage fixation with the BAK system stabilizes the spine in some, but not all, loading directions. The problematic loading directions of extension and axial rotation can be substantially stabilized by using translaminar screw fixation. However, one should emphasize that the degree of stability needed to achieve solid fusion is not known.
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PMID:The role of supplemental translaminar screws in anterior lumbar interbody fixation: a biomechanical study. 984 Apr 74

A minimum 2-year follow-up retrospective review was undertaken to assess our experience with an anterior paramedian muscle-sparing approach to the lumbar spine for anterior spinal fusion (ASF). The records of 28 patients (November 1991 through January 1996) undergoing ASF via a left lower quadrant transverse skin incision (6-10 cm) with a paramedian anterior rectus fascial Z-plasty retroperitoneal approach were reviewed. Diagnosis, number, and level of lumbar interspaces fused, types of fusion, estimated blood loss, length of procedure, length of hospital stay, and complications were analyzed. All cases were completed as either a same-day anterior/posterior (24 of 28) or as a staged procedure at least 1 week after posterior fusion (4 of 28). The General Surgery service performed the muscle-sparing approach, whereas the Orthopedic Spine service performed the ASF. There were 14 men and 14 women, with a mean age of 35.5 years (range, 11-52 years). Diagnoses included spondylolisthesis in 20 cases (including four grade III or IV slips), segmental instability (degenerative or postsurgical) in 7, and 1 flatback deformity. A single level was fused in 20 cases (L4/5 in 4 and L5/S1 in 16), two levels were fused in 5 cases (L4/5 and L5/S1) and three levels were fused in 2 cases (L3/4, L4/5, and L5/S1). The mean length of stay was 7.4 days (range, 5-12 days). The mean estimated blood loss was 300 mL for the anterior procedure alone and 700 ml for both anterior/posterior procedures on the same day. The mean length of operating room time for the anterior approach and fusion was 117 minutes (range, 60-330 minutes). Posterior instrumentation was used in all cases. Anterior interbody struts used included 19 autogenous tricortical grafts, 4 fresh-frozen allografts (2 femoral rings and 2 iliac crests), 3 carbon fiber cages packed with autogenous bone, and a Harms titanium cage with autograft. There was one L5 corpectomy for which a large tricortical allograft strut was utilized. There were no vascular, visceral, or urinary tract injuries. In three cases a mild ileus developed, which resolved spontaneously. We conclude that the anterior paramedian muscle-sparing retroperitoneal approach is safe, uses a small skin incision, avoids cutting abdominal wall musculature, and allows for multiple-level anterior spinal fusions by a variety of interbody fusion techniques. This approach does not require transperitoneal violation or added endoscopic instrumentation, nor does it limit fusion level and technique of fusion, as is the case with the recently popularized laparoscopic approach to the lumbar spine.
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PMID:An open, minimally invasive approach to the lumbar spine. 991 35

Anterior lumbar spine approaches may be indicated for fusion in degenerative lumbar spine disorders or to fill discal and bone gaps after fracture reduction. We present an anterior extraperitoneal approach applicable to any discal and vertebral levels from T12 to S1. The anatomic study, based on 25 cadavers, highlights retroperitoneal dissection principles for easy kidney and duodenopancreatic mobilisation and direct left anterior access to the entire lumbar spine. We established a precise description of the lumbar veins and the anastomoses between the left renal vein and hemiazygos system, in order to define different topographic and anatomic factors related to safe and easily reproducible approaches for cage or graft implementation. Independent of the level and previous intraperitoneal surgery, lumbar spine access with this approach safeguards the kidney, ureter, spleen, hypogastric plexus and duodenopancreatic system. Regarding operating time, blood-loss and possibilities for freshening and grafting, this technique seems an effective counterbalance to the difficulties and complex technology of endoscopic approaches. The clinical study includes our first 42 cases in traumatic and degenerative lesions. Avoiding the neurologic or hemorrhagic risk inherent in classical posterior lumbar interbody fusion (PLIF) techniques, it can be considered as a reasonable and valid alternative. This technique could be used in the near future for mini invasive discal prosthesis insertion.
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PMID:Anatomic basis of minimal anterior extraperitoneal approach to the lumbar spine. 1037 Sep 87

Anterior lumbar interbody fusion (ALIF) cages are expected to reduce segmental mobility. Current ALIF cages have different designs, suggesting differences in initial stability. The objective of this study was to compare the effect of different stand-alone ALIF cage constructs and cage-related features on initial segmental stability. Human multisegmental specimens were tested intact and with an instrumented L3/4 disc level. Five different ALIF cages (I/F, BAK, TIS, SynCage, and ScrewCage) were tested non-destructively in axial rotation, flexion/extension and lateral bending. A cage 'pull-out' concluded testing. Changes in neutral zone (NZ) and range of motion (ROM) were analyzed. Cage-related measurements normalized to vertebral dimensions were used to predict NZ and ROM. No cage construct managed to reduce NZ. The BAK and TIS cages had the largest NZ increase in flexion/extension and lateral bending, respectively. Cages did reduce ROM in all loading directions. The TIS cage was the least effective in reducing the ROM in lateral bending. Cages with sharp teeth had higher 'pull-out' forces. Antero-posterior and mediolateral cage dimensions, cage height and wedge angle were found to influence initial stability. The performance of stand-alone ALIF cage constructs generally increased the NZ in any loading direction, suggesting potential directions of initial segmental instability that may lead to permanent deformity. Differences between cages in flexion/extension and lateral bending NZ are attributed to the severity of geometrical cage-endplate surface mismatch. Stand-alone cage constructs reduced ROM effectively, but the residual ROM present indicates the presence of micromotion at the cage-endplate interface.
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PMID:Biomechanical stability of five stand-alone anterior lumbar interbody fusion constructs. 1076 72

Anterior cervical fusion with interbody bone graft and anterior plating is commonly performed. Unfortunately, the plate has been reported to shield the graft from loading, thus reducing fusion rates. Interbody fusion cages have been effective in the lumbar spine and have gained acceptance in the cervical spine. Twenty-five patients underwent anterior cervical fusion with this modified technique. All patients received anterior diskectomy and corpectomy, placement of an interbody fusion cage packed with corpectomy bone, and application of an anterior cervical plate. Fusion was defined by radiographic evidence of trabecular bone bridging through the cage. No external bracing was used except soft collars as needed. Pre- and postoperative pain scales were completed and statistically analyzed using paired t tests. There were no cases of pseudoarthrosis or major neurological, vascular, or wound complications. There was one case of mild dysphagia that remained unresolved. Mean operative time was comparable to standard instrumented multilevel cervical fusion surgeries. Visual analogue pain scales were significantly improved following surgery. The advantages of using interbody cages with anterior plating include immediate stability and support, elimination of donor site pain from iliac crest bone autograft, and a decrease in pseudoarthrosis by halving the number of fusion surfaces.
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PMID:A modified technique for anterior multilevel cervical fusion. 1207 55

Anterior and posterior thoracic cage translations in the sagittal plane have not been reported for their range of motion and effects on the lumbar spine and pelvis. Twenty subjects volunteered for full-spine radiography in neutral, anterior, and posterior thoracic cage translation postures in a standing position. While grasping an anterior vertical pole, with hands at elbow level, subjects were instructed on how to translate their thoracic cage without any flexion/extension, utilizing a full-length mirror. On the radiographs, all four vertebral body corners of T1 through S1 and the superior margin of the acetabulum were digitized. Segmental and global angles of thoracic kyphosis, sagittal lumbar curvature, and pelvic flexion/extension in translation postures were compared to alignment in the neutral posture. Using the femur heads as an origin, the mean range of thoracic cage translation, measured as horizontal movement of T12 from neutral posture, was found to be 85.1 mm anterior and 73 mm posterior. In anterior translation, the thoracic kyphosis is hypokyphotic (Cobb T1-T12 reduced by 16 degrees). In posterior translation, the segmental angles at T12-L1 and L1-L2 flexed, creating an "S" shape in the sagittal lumbar spine, while the thoracic kyphosis increased by 10 degrees. Using posterior tangents from L1 to L5 and T12 to S1, and Cobb angles at T12-S1, the lumbar curve reduced slightly (by less than 3.3 degrees for all global angle measurements) in anterior translation and reduced by 7.4 degrees, 5.7 degrees, and 8.1 degrees respectively in posterior thoracic translation. The angle of pelvic tilt (measured as the angle of intersection of a line through posterior-inferior S1 to the superior acetabulum and the horizontal) reduced by a mean of 15.9 degrees, and Ferguson's sacral base angle to horizontal reduced by a mean of 13.1 degrees in posterior translation. In anterior translation, pelvic tilt and Ferguson's sacral base angle increased by 15.1 degrees and 12.8 degrees, respectively. The findings of this study show that thoracic cage anterior/posterior translations cause significant changes in thoracic kyphosis (26 degrees ), lumbar curve, and pelvic tilt. An understanding of this main motion and consequent coupled movements might aid the understanding of spinal injury kinematics and spinal displacement analysis on full spine lateral radiographs of low back pain and spinal disorder populations.
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PMID:How do anterior/posterior translations of the thoracic cage affect the sagittal lumbar spine, pelvic tilt, and thoracic kyphosis? 1210 99

Anterior cervical decompression and fusion with anterior plating of the cervical spine is a well-accepted treatment for cervical radiculopathy. Recently, to minimise the extent of surgery, anterior interbody fusion with cages has become more common. While there are numerous reports on the primary stabilising effects of the different cervical cages, little is known about the subsidence behaviour of such cages in vivo. We retrospectively reviewed eight patients with cervical radiculopathy operated upon with anterior discectomy and fusion with a stand-alone titanium cervical cage. During surgery, only the cartilage portion of the end plate was removed and the cages were filled with autologous cancellous bone graft from the iliac crest. To assess possible subsidence or migration, three different radiographic measurements in the sagittal plane were taken for each case, postoperatively and at the latest follow-up. Subsidence was defined as any change in at least one of our parameters of at least 3 mm. Follow-up time was 12-18 months (average 15 months). Five of the nine fused levels had radiological signs of cage subsidence. No posterior or anterior migration was observed. However, subsidence did not correlate with clinical symptoms in four of the five patients. The remaining patient with signs of subsidence, whose neck pain and neurologic symptoms had regressed in the early postoperative course, suffered recurrence of radiculopathy 6 months after the surgery. Her symptoms were explained by the subsidence of the cage and the subsequent foraminal stenosis observed on the magnetic resonance imaging (MRI) scan. At 15 months' follow-up, her cage was broken. Our preliminary results, so far limited in number, represent a serious warning to the proponents of stand-alone cervical cages
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PMID:Subsidence of stand-alone cervical cages in anterior interbody fusion: warning. 1511 77

Anterior lumbar interbody fusion (ALIF) is a widely accepted tool for management of painful degenerative disc disease. Recently, the modern laparoscopic surgical technique has been combined with ALIF procedure, with good early postoperative results being reported. However, the benefit of laparoscopic fusion is poorly defined compared with its open counterpart. This study aimed to compare perioperative parameters and minimum 2-year follow-up outcome for laparoscopic and open anterior surgical approach for L5-S1 fusion. The data of 54 consecutive patients who underwent anterior lumbar interbody fusion (ALIF) of L5-S1 from 1997 to 1999 were collected prospectively. More than 2-years' follow-up data were available for 47 of these patients. In all cases, carbon cage and autologous bone graft were used for fusion. Twenty-five patients underwent a laparoscopic procedure and 22 an open mini-ALIF. Three laparoscopic procedures were converted to open ones. For perioperative parameters only, the operative time was statistically different (P=0.001), while length of postoperative hospital stay and blood loss were not. The incidence of operative complications was three in the laparoscopic group and two in the open mini-ALIF group. After a follow-up period of at least 2 years, the two groups showed no statistical difference in pain, measured by visual analog scale, in the Oswestry Disability Index or in the Patient Satisfaction Index. The fusion rate was 91% in both groups. The laparoscopic ALIF for L5-S1 showed similar clinical and radiological outcome when compared with open mini-ALIF, but significant advantages were not identified, despite its technical difficulty.
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PMID:Comparative study of laparoscopic L5-S1 fusion versus open mini-ALIF, with a minimum 2-year follow-up. 1456 58

Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (score< or =30) on the subjective (quality of life questionnaire) score of 71.8% (28 patients) in the ALIF group and 74.3% (26 patients) in the PLIF group (P>0.05). On categorising Oswestry Index scores into "excellent", "better", "same", and "worse", we found no difference in outcome between the two groups: 79.5% (n=31) had satisfactory outcome with ALIF and 80% (n=28) had satisfactory outcome with PLIF. The rate of return to work was no different in the two groups. On radiological assessment, we found two nonunions in the circumferential fusion (PLIF) group (94.3% fusion rate) and indirect evidence of no nonunions in the ALIF group. There was no significant difference between the compensation rate and disability benefit rate between the two groups. There were three complications in ALIF group and four in the PLIF (circumferential) group. On the basis of these results, we conclude that it is possible to treat discogenic back pain by anterior interbody fusion with Hartshill horseshoe cage or with circumferential fusion using instrumented PLIF.
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PMID:Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion. 1467 17


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