A prospective, randomized, blinded, single-site study to evaluate the clinical and radiographic differences between frozen and freeze-dried allograft when used as part of a circumferential anterior lumbar interbody fusion procedure.

STUDY DESIGN: Prospective, randomized clinical trial from a single surgeon's patient population. OBJECTIVE: The purpose of this study is to compare the outcomes and fusion rates of an anterior lumbar interbody fusion (ALIF) procedure when 2 different preservation methods of the femoral ring allograft (FRA) are used. SUMMARY OF BACKGROUND DATA: FRA can be stored via freeze-drying (FD) or freezing (FZ). In a previous biomechanical PLIF model, FZ cancellous allograft failed at an average load 50% less than FD cancellous allograft. Despite this finding, there is no evidence to support which preservation method is more effective at achieving solid fusion in ALIF procedures. METHODS: Fifty ALIF patients received either FZ or FD FRA. Patients were observed for a minimum of 24 months. Outcome measures included complications, fusion status, implant intactness, 1 to 10 pain scale scores, Oswestry Disability Index (ODI), and SF-36 scores. RESULTS: Univariate comparisons for grafting material are as follows: Average ODI-FD: 46.05 +/- 16.7, FZ: 39.24 +/- 23.65, P = 0.296. Average Physical Component Summary from SF36-FD: 33.47 +/- 10.12, FZ: 39.76 +/- 11.50, P = 0.074. Average 1 to 10 back pain with medication-FD: 3.47 +/- 2.59, FZ: 2.95 +/- 2.48, P = 0.527. ODI scores improved more than 10 points in 62.5% of patients. SF-36 Physical Component Summary scores improved more than 10 points in 27.5% of patients. Back pain with medication scores improved 2 or more points in 60.5% of patients. Seven patients required revision for psuedarthrosis (FD: 6, FZ: 1, P = 0.026). Fusion was achieved in 40 levels (71.4%). The freeze-dried graft had a higher likelihood of pseudarthrosis (P = 0.026). CONCLUSION: When the results are considered in terms of clinical outcomes, the 2 methods of graft preservation perform with few statistically significant differences. Radiographic analysis showed that the freeze-dried graft had a higher likelihood of pseudarthrosis.

A new classification system for degenerative disc disease of the lumbar spine based on magnetic resonance imaging, provocative discography, plain radiographs and anatomic considerations.

Prior attempts to classify degenerative disc disease (DDD) of the lumbar spine have been based on magnetic resonance imaging (MRI) signal intensity. Internal disruption of the disc is not reliably diagnosed by MRI alone. No attempt has been made to include provocative discography and plain radiographs. The intervertebral joint is a three-joint complex consisting not only of the end plate-disc-end plate joint of the anterior column, but also the two facet joints of the posterior column. To date, no classification system for lumbar DDD has taken into account the state of degeneration of the facet joints. In the past this may not have been important with regard to arthrodesis. But as early experience indicates, the degree of degeneration of the facet joints is paramount to the clinical success of an artificial disc replacement. As we transition from intervertebral joint fusion to intervertebral joint replacement, it is imperative that the state of degeneration of the three-joint complex be classified in such a way that all can evaluate lumbar DDD using the same terminology. A new classification system for lumbar DDD is presented. The intervertebral segment is graded in two parts: the anterior column and the posterior column, based on MRI, discography and plain radiographs. The system will be validated through a blinded study of 100 patients requiring stand-alone anterior lumbar interbody fusion or circumferential fusion. Although the debate over which discs are best treated surgically with indication for total disc replacement, or with indication for fusion will continue for some time, the basic understanding of intervertebral disc and posterior facet joint pathology, classified and validated in a simple forthright manner, is essential as we move forward with artificial disc technology.

Single stage anterior cervical reconstruction with titanium mesh cages, local bone graft, and anterior plating.

BACKGROUND CONTEXT: After cervical corpectomy, the use of tricortical autologous bone to fill the large defect is biomechanically and structurally inadequate and may lead to excessive donor site pain and morbidity. The major alternative, fibular strut allograft, has inherent problems that lead to lower rates of solid arthrodesis and graft migration. Majd et al. reported on 34 cases with a 97% solid fusion rate using titanium mesh cages and local bone graft to fill the cervical corpectomy defect. PURPOSE: With long-term results, to confirm the results previously reported by Majd et al. STUDY DESIGN/SETTING: Retrospective chart and radiological review. PATIENT SAMPLE: The first 26 patients in the senior author's practice eligible for a minimum 2-year follow-up, having had cervical corpectomy reconstructed with titanium mesh cages, local bone graft and anterior plating. OUTCOME MEASURES: Odom's criteria were used to assess clinical outcome. Anteroposterior, lateral and lateral flexion and extension radiographs were used to assess fusion. METHODS: Twenty-six patients with multilevel cervical pathology underwent successful corpectomy, decompression and fusion with titanium mesh cages filled with local bone graft. Rigid anterior plating was applied across the corpectomy defect. Preoperative, operative and postoperative chart data were collected retrospectively. Radiographic assessment included a minimum 2-year follow-up. RESULTS: Follow-up ranged from 24 to 64 months. Clinically, 21 of 26 (80.7%) had an excellent or good clinical outcome. No radiolucencies or motion were detected on radiographic analysis, yielding a fusion rate of 100% (26 of 26). Broken or pulled out screws were identified in two patients, one of whom had plate revision. All cages remained intact with no evidence of cage settling or collapse. CONCLUSIONS: The use of titanium mesh cages in conjunction with local bone graft, and rigid anterior plating is effective for cervical reconstruction after corpectomy and a viable alternative to the use of fibular strut allograft. These results confirm those previously reported by Majd et al.

Anterior lumbar interbody fusion with processed sea coral (coralline hydroxyapatite) as part of a circumferential fusion.

STUDY DESIGN: A retrospective review of 20 patients undergoing circumferential lumbar fusion with coralline hydroxyapatite blocks anteriorly and autograft with transpedicular or translaminar facet screw fixation posteriorly. OBJECTIVES: To examine the efficacy of coralline hydroxyapatite as a bone graft substitute for anterior lumbar interbody fusion. SUMMARY OF BACKGROUND DATA: Autograft is the gold standard for bone grafting in the anterior lumbar spine. Harvesting bone from the iliac crest leads to significant postoperative pain and morbidity. Femoral ring allograft is a widely used alternative to autograft but has some inherent problems. Coralline hydroxyapatite was shown to be 100% successful for anterior cervical fusion when combined with rigid plating. METHODS: A retrospective review of 20 patients with low back pain and indicated for surgical intervention. A circumferential instrumented fusion was performed with coralline hydroxyapatite blocks anteriorly and transpedicular or translaminar facet fixation and autograft posteriorly. All patients reached a minimum 3-year clinical and radiologic follow-up. RESULTS: Radiographic follow-up yielded a solid arthrodesis rate of 93.8% by level (30 of 32 disc spaces) and 90% by patient (18 of 20). Clinical follow-up generated a mean pain reduction of 61.8% with clinical success demonstrated in 80% (16 of 20) of all patients who reported good or excellent pain relief. Eight of 12 (66.7%) patients employed before surgery returned to work in some capacity. CONCLUSIONS: Coralline hydroxyapatite is a practicable anterior lumbar interbody fusion alternative to autograft and allograft as part of a circumferential fusion with rigid posterior fixation. It is not recommended for stand-alone anterior lumbar interbody fusion without further study.

Anterior lumbar interbody fusion with titanium mesh cages, coralline hydroxyapatite, and demineralized bone matrix as part of a circumferential fusion.

BACKGROUND CONTEXT: Anterior lumbar interbody fusion (ALIF) has become one of the primary choices for eliminating motion between vertebral segments in patients with severe discogenic pain and other lumbar pathologies. Autograft is the gold standard for spinal fusion. However, multiple authors have reported complication and morbidity rates associated with iliac crest harvesting to be as high as 25%. Drawbacks to the use of allograft in the anterior column include slower incorporation rates, the possibility for disease transmission, increasing cost resulting from stringent processing and unavailability on a worldwide basis resulting from religious and economic concerns. PURPOSE: To determine the clinical and arthrodesis efficacy of coralline hydroxyapatite as an osteoconductive bone graft substitute in the anterior lumbar spine using a titanium mesh cage. STUDY DESIGN: A series of 50 patients returning for long-term prospective follow-up, implanted with titanium mesh cages filled with coralline hydroxyapatite and demineralized bone matrix for ALIF as part of a circumferential fusion. PATIENT SAMPLE: Long-term clinical and radiographic follow-up were examined for the first 50 patients undergoing this technique by one surgeon. OUTCOME MEASURES: Pain was measured with a visual analog scale and function was measured with the Oswestry Disability Index. METHODS: All 50 patients underwent successful ALIF with titanium mesh cages, coralline hydroxyapatite and demineralized bone matrix, as well as an autologous posterolateral fusion with rigid posterior instrumentation. Patients filled out follow-up questionnaires and appropriate radiographs were taken. RESULTS: A solid fusion rate of 96% was achieved. Mean pain decrease was 60% overall. A total of 70% of all patients either returned to work or to full home activities at a mean of 8 months after surgery. Ninety percent felt the surgery was successful. CONCLUSIONS: The combination of titanium mesh cages, coralline hydroxyapatite and demineralized bone matrix is effective for anterior interbody fusion of the lumbar spine when used as part of a rigidly instrumented circumferential fusion.

Bone grafting alternatives in spinal surgery.

BACKGROUND CONTEXT: Bone grafting is used to augment bone healing and provide stability after spinal surgery. Autologous bone graft is limited in quantity and unfortunately associated with increased surgical time and donor-site morbidity. Alternatives to bone grafting in spinal surgery include the use of allografts, osteoinductive growth factors such as bone morphogenetic proteins and various synthetic osteoconductive carriers. PURPOSE: Recent research has provided insight into methods that may modulate the bone healing process at the cellular level in addition to reversing the effects of symptomatic disc degeneration, which is a potentially disabling condition, managed frequently with various fusion procedures. With many adjuncts and alternatives available for use in spinal surgery, a concise review of the current bone grafting alternatives in spinal surgery is necessary. STUDY DESIGN/SETTING: A systematic review of the contemporary English literature on bone grafting in spinal surgery, including abstract information presented at national meetings. METHODS: Bone grafting alternatives were reviewed as to their efficacy in extending or replacing autologous bone graft sources in spinal applications. RESULTS: Alternatives to autologous bone graft include allograft bone, demineralized bone matrix, recombinant growth factors and synthetic implants. Each of these alternatives could possibly be combined with autologous bone marrow or various growth factors. Although none of the presently available substitutes provides all three of the fundamental properties of autograft bone (osteogenicity, osteoconductivity and osteoinductivity), there are a number of situations in which they have proven clinically useful. CONCLUSIONS: Alternatives to autogenous bone grafting find their greatest appeal when autograft bone is limited in supply or when acceptable rates of fusion may be achieved with these substitutes (or extenders) despite the absence of one or more of the properties of autologous bone graft. In these clinical situations, the morbidity of autograft harvest is reasonably avoided. Future research may discover that combinations of materials may cumulatively result in the expression of osteogenesis, osteoinductivity and osteoconductivity found in autogenous sources.