A prospective randomized comparison of rectangular titanium cage fusion and iliac crest autograft fusion in patients undergoing anterior cervical discectomy. Rigid fusion after cloward operation for cervical disc disease using autograft, allograft, or xenograft: a randomized study with radiostereometric and clinical follow-up assessment. Autograft versus interbody fusion cage without plate fixation in the cervical spine: a randomized clinical study using radiostereometry. A randomized prospective study of an anterior cervical interbody fusion device with a minimum of 2 years of follow-up results. A prospective, randomized controlled clinical trial of anterior lumbar interbody fusion using a titanium cylindrical threaded fusion device. A prospective randomized comparison between the cloward procedure and a carbon fiber cage in the cervical spine: a clinical and radiologic study. Radiographic analysis of fusion progression following one-level cervical fusion with or without plate fixation. Comparison of anterior cervical fusions using autogenous bone graft obtained from the cervical vertebrae to the modified Smith-Robinson technique. Clinical and radiological evaluation of Trabecular Metal and the Smith-Robinson technique in anterior cervical fusion for degenerative disease: a prospective, randomized, controlled study with 2-year follow-up.
The authors compare clinical outcome and fusion rates after iliac crest autograft (ICAG)- and rectangular titanium cage (RTC)-augmented fusion in patients undergoing anterior cervical discectomy (ACD).
                One hundred consecutive patients with 127 levels of cervical disc disease refractory to conservative treatment were randomized into one of the two treatment groups (ICAG/RTC fusion). The visual analog scale was used by the patient to rate overall pain and head, neck, arm, and donor site pain separately. Myelopathy was documented according to Japanese Orthopaedic Association and Nurick grading systems. Outcome was analyzed using Odom criteria, the 36-Item Short Form (SF-36), and Patient Satisfaction Index scales. Fusion rates were assessed on standard and flexion-extension radiographs. Follow-up data of at least 12 months' duration were available for 95 patients. More residual overall pain after 12 months was documented in patients who underwent ICAG fusion (3.3 +/- 2.5 [ICAG] and 2.2 +/- 2.4 [RTC]; p < 0.05). Although arm and head pain were minimal in both groups, neck pain proved to be the predominant symptom (2.7 +/- 2.5 [ICAG] and 1.9 +/- 2.1 [RTC]), which resolved in only 67 and 48% of RTC- and ICAG-treated patients, respectively (p < 0.05). Myelopathy improved comparably in both groups. Regardless of increased pain in ICAG-treated patients, PSI and SF-36 scores were not significantly different between groups (only four [8%] of 47 ICAG-treated patients and five [10%] of 48 RTC-treated patients were unsatisfied). Good to excellent functional recovery according to Odom criteria was observed in 75 and 79% of ICAG- and RTC-treated patients, respectively. Fusion rates were 81 and 74%, respectively (p = 0.51).
                Fusion rates and clinical outcome at 12 months after ACD were comparable between patients who underwent ICAG and RTC fusion. The use of rectangular cages, however, avoids donor site morbidity and reduces overall pain and, thus, seems to be an advantageous treatment alternative. In this study, 43 patients scheduled for a single-level cervical Cloward procedure for disc disease were randomized prospectively to fusion with autograft, allograft, or xenograft.
                To outline any differences in fusion over time in terms of final mobility and clinical outcome between the three bone grafts.
                Fusion is used to relieve pain from a spinal segment. The bovine xenograft gives a fibrous fusion in contrast to the solid bone fusion obtained with autograft from the iliac crest, but no definite differences in clinical outcome have been shown previously after surgery at a single level.
                By use of radiostereometric analysis, 33 patients were observed after 6, 12, and 24 to 50 (mean, 37) months. All 43 patients underwent clinical examination, which involved pain rating before and after surgery, with a final follow-up assessment by an unbiased observer.
                Mobility could be demonstrated in 9 patients after 1 year and in 6 patients at the final follow-up assessment, without pain, and with no difference between bone grafts. The patients who received autograft experienced a greater reduction of pain than the patients treated with xenograft.
                Most of the patients healed with a rigid fusion no matter which graft was used, but the healing process took longer than expected. The clinical results were not influenced by whether mobility could be demonstrated. There was a tendency toward better clinical results in the patients treated with autograft. A primary object with a fusion cage is avoidance of graft collapse with subsequent subsidence and malalignment of the cervical spine that is observed after bone grafting alone. No randomized studies exist that demonstrate the difference between these two methods in terms of graft subsidence and angulation of the fused segment. The size of the study population was calculated to be 24 patients to reach a significant difference at the 95% CI level. Patients with one-level cervical radiculopathy scheduled for surgery were randomized to anterior discectomy and fusion (ACDF) with autograft or to fusion cage, both without plate fixation. Tantalum markers were inserted in the two adjacent vertebrae at the end of surgery. Radiostereometry was performed immediately postoperatively and at regular intervals for 2 years. Questionnaires were used to evaluate the clinical outcome and an unbiased observer graded the outcome after 2 years. No significant differences were found between the two methods after 2 years in regard of narrowing of the disc space (mean 1.7 and 1.4 mm, respectively) or deformation of the fused segment into flexion (mean 7.7 degrees and 4.6 degrees , respectively). Patients in the cage group had a significantly better clinical outcome. The findings of subsidence and flexion deformation of the fused segment after 2 years seem to be of no clinical importance after one-level cervical disc surgery. However, in multi-level surgery using the same methods, an additive effect of the deformations of the fused segments may affect the clinical outcome. Despite variations in technique, inherent problems persist with current approaches to anterior cervical fusion. This study was performed to determine whether anterior cervical fusion performed using an investigational device was safe and effective in the treatment of degenerative cervical disc disorders and whether this device offered advantages over current techniques.
                Fifty-four patients with radiculopathy with or without mild myelopathy due to one- or two-level cervical degenerative disc disease were randomized as part of a Food and Drug Administration device study. Following microsurgical discectomy, the control group was treated with iliac crest graft fusion; the experimental study group underwent insertion of an interspace cage and placement of a local autograft. All patients received postoperative follow-up care for at least 2 years. Good or excellent results were found in approximately 97% of the experimental group and 88% of the control group. A solid fusion was achieved in all patients who underwent one-level cage placement, and a solid fusion at one or both levels was achieved in over 90% of both groups. Chronic donor site pain was reported by 31% of the control group.
                In this study, the use of an interbody fusion cage avoided donor site morbidity and placement of autograft achieved a high rate of good or excellent results. Interbody fusion cages appear safe and effective, and their use helps to avoid some of the inherent problems in performing current anterior cervical fusion techniques. A prospective, randomized, controlled clinical trial comparing a cylindrical threaded titanium cage to a femoral ring allograft control for anterior lumbar interbody fusion.
                To compare these two implants with regard to arthrodesis. Secondary outcome measures included pain relief, neurological status, and general health status.
                Anterior lumbar interbody fusion is a well-accepted procedure using trapezoidal femoral ring allografts or cylindrical titanium cages. Clinical and biomechanical studies evaluating these two distinct constructs are numerous; however, no prospective, randomized study comparing them has been done.
                A multicenter trial of 140 patients: 78 were randomized to the cylindrical threaded titanium cage device treatment arm and 62 patients randomized into the control group. All had autogenous iliac crest bone graft packed into the device. All patients had a single-level stand-alone anterior lumbar interbody fusion at either the L4-L5 or L5-S1 interspace for symptomatic degenerative disc disease. Radiographic fusion data were collected as well as multiple types of outcome data, including pain/disability scores, neurologic status, and overall health.
                At 12 months, 97% of the cylindrical threaded titanium cage device group and 40% of the control group demonstrated radiographic fusion. At 24 months, 97% of the cylindrical threaded titanium cage group and 52% of the control group showed radiographic fusion. These fusion rate differences are statistically significant (P < 0.001). The Oswestry and neurologic scores were not significantly different between groups.
                This is the first prospective, randomized, multicenter clinical trial that compares fusion cage results to control data.
                Cylindrical threaded titanium cages have a higher fusion rate, comparable improvements in clinical outcome (Oswestry, Low Back Pain Questionnaire, SF-36), and fewer secondary supplemental fixation procedures compared to the femoral ring allograft control. A prospective randomized study was conducted.
                To determine whether the use of a cervical carbon fiber intervertebral fusion cage improves the outcome of anterior cervical decompression and fusion, as compared with the Cloward procedure using autograft.
                Despite the theoretical advantages of using intervertebral cages, including reduced donor site morbidity and prevention of graft collapse, an improved clinical outcome has not yet been documented.
                For this study, 103 patients were randomized to anterior cervical decompression and fusion with a carbon fiber intervertebral fusion cage (n = 52) or the Cloward procedure (n = 51). An independent observer quantified pain and functional disability. Fusion rate, segmental kyphosis, and disc height were assessed by radiographs.
                During a mean follow-up period of 36 months (range, 24-72 months) for 89 patients (86%), the pain and disability were similar for both treatments. Postoperative donor site pain was significantly less in the carbon fiber intervertebral fusion cage group. The fusion rate was 86% in the Cloward procedure group and 62% in the carbon fiber intervertebral fusion cage group (P < 0.05). In the latter group, patients with pseudarthrosis reported more severe pain than fused patients (51 and 33 visual analog scores, respectively), but the difference was not significant. The segmental kyphosis was less and the disc height increased in the carbon fiber intervertebral fusion cage group, as compared with the Cloward procedure group. Disc height was not correlated with outcome. Segmental kyphosis showed a weak (r = -0.3) but significant (P < 0.05) correlation with improvement of the Cervical Spine Functional Score, but not with other outcome variables.
                Except for reduced donor site pain, the clinical outcome for the carbon fiber intervertebral fusion cage is the same as for the Cloward procedure. Use of the cage results in a more lordotic alignment and an increased disc height, but in a higher pseudarthrosis rate than use of the Cloward procedure. Anterior cervical discectomy and fusion (ACDF) using bone graft or a cage with plate fixation is an accepted technique for the treatment of symptomatic degenerative disc disease. It is, however, debatable whether a plate is really necessary to increase the progress of fusion. Thus, the aim of this randomized and controlled prospective study was to evaluate whether ACDF with a cage and anterior plate fixation results in a greater progress of fusion compared with ACDF using a stand-alone cage.
                37 candidates for ACDF were treated either with a stand-alone cage (study group) or with a cage+plate fixation (control group). 19 patients were randomized to be stabilized with a stand-alone cage and 18 patients were treated with a cage and additional anterior plate fixation. The progress of cervical fusion over time was compared by radiostereometric analysis (RSA). Follow-up examinations pre- and postoperatively were done using the Visual Analogue Scale (VAS) for neck and arm pain. Radiographic assessment of fusion using an RSA-control was done after one, six and twelve weeks, as well as after six months, and one and two years postoperatively. Mann-Whitney test for unpaired values was used to determine the statistical differences in residual intervertebral motion.
                Three-dimensional analysis of segmental motion (left-right, cranio-caudal, and posterior-anterior) did not reveal any statistical differences between both groups at any examination time postoperatively ( P>0.05). The VAS score did not differ between the groups ( P>0.05).
                Anterior plate fixation did not demonstrate an improvement in the progress of fusion in one-level ACDF. Anterior cervical discectomy and interbody grafting provide excellent results in treating cervical radiculopathy. This prospective study compares the results of the technique obtaining autogenous bone from the cervical vertebrae for grafting to the modified Smith-Robinson technique using autogenous iliac crest graft. Seven levels in six patients were fused using the vertebral body autograft technique and 43 levels in 40 patients using the standard technique. All patients had radiculopathy and neck pain. Statistically significant differences in fusion rate (4/7 vertebral body autograft; 40/43 modified Smith-Robinson) (p = 0.029), disc height maintenance (p = 0.001), and neck pain improvement (p = 0.05) occurred between the techniques. We do not recommend vertebral body autograft over the modified Smith-Robinson technique for anterior cervical fusion following discectomy. A prospective, randomized, controlled study was carried out to compare the radiological and clinical outcomes after anterior cervical decompression and fusion (ACDF) with Trabecular Metal (TM) to the traditional Smith-Robinson (SR) procedure with autograft. The clinical results of cervical fusion with autograft from the iliac crest are typically satisfactory, but implications from the donor site are frequently reported. Alternative materials for cervical body interfusion have shown lower fusion rates. Trabecular Metal is a porous tantalum biomaterial with structure and mechanical properties similar to that of trabecular bone and with proven osteoconductivity. As much as 80 consecutive patients planned for ACDF were randomized for fusion with either TM or tricortical autograft from the iliac crest (SR) after discectomy and decompression. Digitized plain radiographic images of 78 (98%) patients were obtained preoperatively and at 2-year follow-up and were subsequently evaluated by two senior radiologists. Fusion/non-fusion was classified by visual evaluation of the A-P and lateral views in forced flexion/extension of the cervical spine and by measuring the mobility between the fused vertebrae. MRI of 20 TM cases at 2 years was successfully used to assess the decompression of the neural structures, but was not helpful in determining fusion/non-fusion. Pain intensity in the neck, arms and pelvis/hip were rated by patients on a visual analog scale (VAS) and neck function was rated using the Neck Disability Index (NDI) the day before surgery and 4, 12 and 24 months postoperatively. Follow-ups at 12 and 24 months were performed by an unbiased observer, when patients also assessed their global outcome. Fusion rate in the SR group was 92%, and in the TM group 69% (P < 0.05). The accuracy of the measurements was calculated to be 2.4 degrees . Operating time was shorter for fusion with TM compared with autograft; mean times were 100 min (SD 18) and 123 min (SD 23), respectively (P = 0.001). The patients' global assessments of their neck and arm symptoms 2 years postoperatively for the TM group were rated as 79% much better or better after fusion with TM and 75% using autograft. Pain scores and NDI scores were significantly improved in both groups when compared with baseline at all follow-ups, except for neck pain at 1 year for the TM group. There was no statistically significant difference in clinical outcomes between fusion techniques or between patients who appeared radiologically fused or non-fused. There was no difference in pelvic/hip pain between patients operated on with or without autograft. In our study, Trabecular Metal showed a lower fusion rate than the Smith-Robinson technique with autograft after single-level anterior cervical fusion without plating. There was no difference in clinical outcomes between the groups. The operative time was shorter with Trabecular Metal implants.
When the working mechanism for pain relief and functional improvement is fusion of the motion segment, there is low quality evidence that iliac crest autograft appears to be the better technique. When ignoring fusion rates and looking at complication rates, a cage has a weak evidence base over iliac crest autograft, but not over discectomy alone. Future research should compare additional instrumentation such as screws, plates, and cages against discectomy with or without autograft.