The role of vascularized bone grafts in spine surgery

The use of vascularized bone grafts in complex spine reconstruction is particularly attractive in situations that involve large segmental bone defects, failed previous attempts at arthrodesis, poor soft tissue beds secondary to infection or radiation exposure necrosis or failed arthrodesis in neuromuscular disease processes. This article details the indications and rationale for vascularized bone grafting as well as the results of vascularized bone grafting of the spine.     

Application of bone grafts in podiatric surgery

The application of bone grafting was first reported in the late 1600s, but has only recently become widely used in podiatric surgery. This increase can be accredited to many sources, such as the recent surge in literature advocating its use and the advances in allograft technology that have made it more readily available. There are many new types of allograft bone implants evolving each year with better osteogenic potential and structural rigidity.     

Vascularized skull bone grafts in craniofacial surgery

Vascularized skull bone grafts based on a pedicle of temporalis muscle have been used in 30 zygomatic arch and malar reconstructions, 1 mandible reconstruction, and 1 palate reconstruction. The surgical technique, complications, and postoperative results are reviewed. Technetium bone scans obtained within one week of operation confirm blood supply to the transferred bone. After a mean follow-up of 13 months, there is no evidence of bone graft resorption. We have used a team approach and careful surgical technique, and no serious complications have been encountered.     

Plastic surgery of abdominal hernias using synthetic grafts]

Synthetic grafts were used for plastic surgery of abdominal hernias in 82 patients. Made in Russia carbonic woven implants were used in 20 cases, American monofilament polypropilene net--in 62. Indications for synthetic grafts were postoperative recurrent hernias, large postoperative hernias and unsuitability of self-tissues for autoplasty. In postoperative period seroma was seen in 4 patients, suppuration of surgical wounds--in 2. There were no recurrences and lethal outcomes. Synthetic grafts permit to repair any abdominal hernia regardless of it size and anatomic state of tissues, to expand indications for surgery in patients with concomitant diseases.     

A systematic review of comparative studies on bone graft alternatives for common spine fusion procedures

Background

The increased prevalence of spinal fusion surgery has created an industry focus on bone graft alternatives. While autologous bone graft remains the gold standard, the complications and morbidity from harvesting autologous bone drives the search for reliable and safe bone graft substitutes. With the recent information about the adverse events related to bone morhogenetic protein use, it is appropriate to review the literature about the numerous products that are not solely bone morphogenetic protein.

Purpose

The purpose of this literature review is to determine the recommendations for use of non-bone morphogenetic protein bone graft alternatives in the most common spine procedures based on a quantifiable grading system.

Study design

Systematic literature review.

Methods

A literature search of MEDLINE (1946–2012), CINAHL (1937–2012), and the Cochrane Central Register of Controlled Trials (1940–April 2012) was performed, and this was supplemented by a hand search. The studies were then evaluated based on the Guyatt criteria for quality of the research to determine the strength of the recommendation.

Results

In this review, more than one hundred various studies on the ability of bone graft substitutes to create solid fusions and good patient outcomes are detailed.

Conclusion

The recommendations for use of bone graft substitutes and bone graft extenders are based on the strength of the studies and given a grade.     

Update on cranial bone grafts in craniofacial surgery

A large series of cranial bone grafts performed during a 6-year period is presented. The types of grafts are discussed and the techniques of taking the grafts are described. The complications have been few. Full-thickness skull penetration occasionally occurs but should not be a cause for concern. The skull has gradually become our main bone graft donor site.     

Compressive strength of autologous and allogenous bone grafts for thoracolumbar and cervical spine fusion

The selection of the bone graft type for stabilization of spinal fusion depends on availability, the clinical situation, and the desired mechanical stability. The authors determined the potential immediate postoperative compressive strength of various types of bone grafts under axial compression on a material testing machine. The fibular strut graft (5,070 +/- 3,250 N, mean +/- standard deviation [SD]) was significantly stronger (P less than 0.05) than the anterior (1,150 +/- 487 N) and posterior (667 +/- 311 N) iliac crest grafts, and the rib grafts (452 +/- 192 N). Hydroxyapatite grafts with a pore size of 200 mu were significantly stronger (P less than 0.05) than those with a pore size of 500 mu (1,420 +/- 480 N versus 338 +/- 78 N). Ethylenoxide sterilization had no significant effect on the immediate compressive strength. Bicortical and tricortical Bailey-Badgley and Cloward bone grafts also were compared. Results showed that all cervical graft types may be sufficiently strong to support sizable loads.     

Evolution of biological and synthetic grafts in reconstructive pelvic surgery

Surgery is an evolving science in the attempt to make surgical procedures more effective, safer, and less invasive. Recurrence and subsequent re-operation for stress incontinence and prolapse has been reported to be necessary in one of three patients, so there is a need for improvement [1]. In reconstructive pelvic surgery (RPS), the use of biological and synthetic grafts for the transabdominal and transvaginal treatment of pelvic organ prolapse (POP) or stress urinary incontinence (SI) has improved long-term support and function after surgery. However, the potential benefits of using grafts need to be carefully balanced against the risks of using materials foreign to the patient’s body. Pelvic organ prolapse develops secondary to defective endopelvic fascial and muscular support. The levator ani provides resting tonic muscular support for all three pelvic compartments. Once neuromuscular damage occurs, extra strain is placed on the connective tissue supports, which may also subsequently fail. To date, there is no surgery that adequately addresses the issue of neuromuscular damage of the pelvic floor musculature. In conventional POP surgery, defective support is repaired by suturing of the patient’s own connective tissue, fascia, or ligaments. The rationale for the use of grafts is to reinforce and strengthen pelvic organ repairs similar to the use of grafts to strengthen abdominal hernia repair.     

Conservative alternatives to radical surgery for favorable rectal cancers

Selected cases of favorable rectal cancer can be treated with less than radical surgery. The literature demonstrates that excellent local control can be achieved using either local excision or carefully confined high dose radiation to treat the primary tumor site. Two treatments to the tumor site appear equally effective: local excision (usually a full thickness en bloc procedure) or low energy (50 kVp) endocavitary radiation. For many patients treated conservatively there is also a role for external beam radiation to the pelvis-this treats subclinical disease in regional nodes and around the tumor bed. The locoregional control for T1 lesions is excellent. For T2 lesions about 15% of patients can experience recurrence after conservative treatment. Close follow up of these patients is important, since local failures after conservative treatment are more amenable to salvage surgery than failures after standard radical surgery. Careful selection of cases, using endorectal ultrasound or MRI whenever possible, is important. The incidence of unexpected T3 disease or tumor at the margin of resection has been reported as high as 40% in series that do not utilize endorectal T staging.     

Assessing underlying bone quality in spine surgery patients: a narrative review of dual-energy X-ray absorptiometry (DXA) and alternatives

Poor bone quality and low bone mineral density (BMD) have been previously tied to higher rates of postoperative mechanical complications in patients undergoing spinal fusion. These include higher rates of proximal junctional kyphosis, screw pullout, pseudoarthrosis, and interbody subsidence. For these reasons, accurate preoperative assessment of a patient's underlying bone quality is paramount for all elective procedures. Dual-energy X-ray absorptiometry (DXA) is currently considered to be the gold standard for assessing BMD. However, a growing body of research has suggested that in vivo assessments of BMD using DXA are inaccurate and have, at best, moderate correlations to postoperative mechanical complications. Consequently, there have been investigations into using alternative methods for assessing in vivo bone quality, including using computed tomography (CT) and magnetic resonance imaging (MRI) volumes that are commonly obtained as part of surgical evaluation. Here we review the data regarding the accuracy of DXA for the evaluation of spine bone quality and describe the alternative imaging modalities currently under investigation.     

Temporal analysis of vascularized and nonvascularized rib grafts in canine spine surgery

The authors have previously reported work demonstrating the superiority of vascularized vs. nonvascularized rib grafts, which were inlaid to bridge three vertebral bodies studied at 3 months postoperatively. They questioned whether the mechanical and biologic properties of the nonvascular grafts would improve over time to approach the performance of the vascularized grafts by 6 months. They found that, with increased time, the vascularized grafts continued to improve, showing hypertrophy, maintenance of cortical integrity, and bonding to the recipient vertebral bodies. The nonvascularized grafts, however, showed porosity, fragmentation, and replacement by spongiosa. Mechanical properties showed increased performance in the vascularized vs. nonvascularized grafts, and no improvement was seen between the nonvascularized grafts from 3 to 6 months.     

Intraoperative extracorporeal autogenous irradiated bone grafts in tumor surgery

There are several procedures for reconstruction of bony defects after resection of malignant musculoskeletal tumors. The clinical results of intraoperative extracorporeal autogenous irradiated bone grafts in 20 patients with musculoskeletal tumors are discussed. The authors' method of treatment consists of: (1) wide en bloc resection of the tumor with involved bone; (2) curettage of the tumor from the resected bone; (3) extracorporeal irradiation with 50 Gy as a bolus single dose to the isolated bone; and (4) reimplantation of the irradiated bone into the host with fixation devices. Twelve bone sarcomas and eight soft tissue sarcomas with bone involvement were treated surgically with this reconstruction method after wide resection of the tumors. The irradiated bone was used as an intercalary graft in seven cases, as an osteoarticular graft in 11 cases, and as a hemicortical graft in two cases. The theoretical advantages of this method are certain sterilization of tumor cells with radiation, easy availability and good adaptation of size and shape, no risk of disease transmission, preservation of bone stock and ligamentous tissue, and no immunologic reaction. Radiologically, bony union occurred in 23 of 29 (79%) osteotomy sites. The overall radiographic evaluation rating was 74% and the functional rating was 73% according to the International Society of Limb Salvage rating system. Nonunion (20%) and infection (15%) were the two major complications. Preservation of the tendon insertions and ligamentous structures of the irradiated bone seemed to restore excellent joint function. No local recurrence was detected from the irradiated bones during the mean followup of 45 months. These results indicate intraoperative extracorporeal irradiated bone graft can be a widely applicable method for reconstruction in tumor surgery.     

Metallic plate stabilisation of bone grafts in craniofacial surgery

The use of Champy miniplates to stabilise bone grafts in osseous defects following craniofacial and orbital osteotomies is discussed. The advantages of these methods are decrease in operating time, accurate fit of the bone graft and the fixation of the bone graft in the plane of the plate, thus placing it exactly into the correct position in relation to the osteotomy. Total stability is obtained and, in maxillary advancement, intermaxillary fixation may not be necessary. This is useful in children and at all ages adds to the postoperative safety. There may be less relapse with this rigid internal fixation. Long term follow-up will be required to determine whether this statement is true. Although the plates are expensive, it is felt that the reduction in operating time outweighs this.     

New grafts for old? A review of alternatives to autologous skin.

Immediate resurfacing of skin defects is a challenging prospect, especially in patients with extensive full-thickness burns. Currently, split-thickness autografts offer the best form of wound coverage, but limited donor sites and their associated morbidity have prompted the search for alternatives. The application of allogeneic skin is restricted by availability and the risk of transmission of infection, whilst synthetic skin substitutes are simply expensive dressings. The problems of limited expansion may be overcome by culturing keratinocytes in vitro. Unlike autologous cells, allogeneic keratinocytes are available immediately, although they survive for less than a week when applied to full-thickness skin defects. Moreover, the absence of a dermal component in these grafts predisposes to instability and contracture. A cross-linked collagen and glycosaminoglycan dermal substitute, covered with thin split-skin grafts or cultured autologous keratinocytes, shows promise in burns patients. An alternative is a collagen matrix populated by allogeneic fibroblasts and overlaid with cultured autologous or allogeneic keratinocytes. The clinical application of cultured grafts remains imperfect but offers the prospect of immediate coverage and massive expansion.     

Failure of autologous fat grafts to prevent postoperative epidural fibrosis in surgery of the lumbar spine

In three cases of lumbar disc herniation, autologous fat grafts were inserted over the dura mater and the exposed nerve roots during surgery with the aim of preventing postoperative epidural fibrosis. A second operation had to be performed in two of these cases as a result of the radiographic appearance of excessive scar formation in the epidural and adjacent regions of the nerve root giving rise to symptoms. In the third patient, myelographic studies revealed the development of this type of hypertrophic scarring; however, the patient refused a further operation. The hypertrophic epidural scarring occurred in these three cases despite the presence of autologous fat grafts. Histopathological examination of the fat removed from the two patients who were operated on a second time showed a fibrotic infiltration into the fat graft.