The use of bone graft substitutes in large cancellous voids: any specific needs?

Bone graft is the second most common transplantation tissue, with blood being by far the commonest. Autograft is considered ideal for grafting procedures, providing osteoinductive growth factors, osteogenic cells and an osteoconductive scaffold. Limitations, however, exist regarding donor site morbidity and graft availability. Allograft on the other hand poses the risk of disease transmission. Synthetic graft substitutes lack osteoinductive or osteogenic properties. Composite grafts combine scaffolding properties with biological elements to stimulate cell proliferation and differentiation and eventually osteogenesis. We present here an overview of bone graft substitutes available for clinical application in large cancellous voids.     

Posterolateral spinal fusion in a rabbit model using a collagen–mineral composite bone graft substitute

Choosing the appropriate graft material to participate in the healing process in posterolateral spinal fusion continues to be a challenge. Combining synthetic graft materials with bone marrow aspirate (BMA) and autograft is a reasonable treatment option for surgeons to potentially reduce or replace the need for autograft. FormaGraft, a bone graft material comprising 12% bovine-derived collagen and 88% ceramic in the form of hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) was evaluated in three possible treatment modalities for posterior spinal fusion in a standard rabbit model. These three treatment groups were FormaGraft alone, FormaGraft soaked in autogenous BMA, and FormaGraft with BMA and iliac crest autograft. No statistically demonstrable benefits or adverse effects of the addition of BMA were found in the current study based on macroscopic, radiology or mechanical data. This may reflect, in part, the good to excellent results of the collagen HA/TCP composite material alone in a well healing bony bed. Histology did, however, reveal a benefit with the use of BMA. Combining FormaGraft with autograft and BMA achieved results equivalent to autograft alone. The mineral and organic nature of the material provided a material that facilitated fusion between the transverse processes in a standard preclinical posterolateral fusion model.     

Can autologous bone culture predict spinal fusion capacity?

The capacity of the individual patient to initiate osteoblast proliferation as a predictor for successful lumbar spinal fusion has not yet been reported. The objectives of this study were, first, to analyze the relationship between in vitro osteoblast proliferation and clinical bony fusion in the individual patient in order to predict the fusion outcome and, second, to measure the effect of preoperative tobacco smoking on osteoblast proliferation. Sixty-one patients (mean age 46 years) underwent posterolateral lumbar fusion in the period 1994–1995. Thirty-eight patients received CD pedicle screw implants and 23 received posterolateral fusions alone. During surgery, autogenous iliac bone was harvested and 1 g of trabecular bone without blood or bone marrow was then isolated for cell culturing. The cultures were classified as excellent (confluence within 4 weeks), good (confluence between 4 and 6 weeks) and poor (no or poor growth). Spine fusion was evaluated by two independent observers from plain anterior-posterior, lateral, and flexion/extension radiographs taken 1 year postoperatively, and the functional outcome was measured by the Dallas Pain Questionnaire (DPQ). Twenty-three patients had excellent, 19 good, and 19 poor in vitro osteoblast proliferation. Bony fusion was obtained in 77% of patients: 83% in the CD instrumentation group and 70% in the non-instrumentation group (NS). There was no significant correlation between osteoblast proliferation and spinal fusion or functional outcomes when analyzing the CD instrumentation and non-instrumentation groups together or separately. Elderly patients had a significantly poorer osteoblast proliferation than younger patients (P < 0.008). Preoperative tobacco consumption had no discernible effect on osteoblast proliferation, and no correlation between smoking and fusion was found. Further refinement of autologous osteoblast culturing may provide a biological tool for selection of patients who require biological enhancement of their bone fusion capacity. The poorer osteoblast proliferation related to advanced age supports the important negative biological influence of age on bony fusion. However, with more sensitive testing and better discrimination, other results are possible – or can in any event not be excluded. Received: 17 April 1998 Revised: 10 September 1998 Accepted: 12 October 1998     

RETRACTED: Bone graft substitutes: What are the options?

Currently, a number of bone grafting materials are available in the clinical setting to enhance bone regeneration, varying from autologous bone to several bone graft substitutes. Although autologous bone remains the "gold standard" for stimulating bone repair and regeneration, the morbidity from its harvesting and its restricted availability generated the need for the development of other materials or strategies either to substitute autologous bone graft or expand its limited supply. Bone graft substitutes can possess one or more components: an osteoconductive matrix, acting as a scaffold; osteoinductive proteins and other growth factors to induce differentiation and proliferation of bone-forming cells; and osteogenic cells for bone formation. Based on their distinct properties, all these bone grafting alternatives have specific indications, and can be used either alone or in combination. In this review, we summarise the available bone grafting materials, focussing mainly on the various bone substitutes and their characteristics, in an effort to specify the indications for their use.     

What injuries should we expect in the emergency room?

IntroductionBeside serious and potentially fatal injuries, the majority of pediatric trauma patients present with minor injuries to emergency departments. The aim of this study was to evaluate age-related injury pattern, trauma mechanism as well as the need for surgery in pediatric patients.Patients and methodsRetrospective Study from 01/2008 to 12/2012 at a level I trauma center. All patients <18 years of age following trauma were included. Injury mechanism, injury pattern as well as need for surgery were analyzed according to different age groups (0–3 years, 4–7 years, 8–12 years and 13–17 years). Major injuries were defined as fractures, dislocations and visceral organ injuries. Minor injuries included contusions and superficial wounds.ResultsOverall, 15300 patients were included (59% male, median age 8 years). A total of 303 patients (2%) were admitted to the resuscitation room and of these, 69 (0.5% of all patients) were multiply injured (median Injury Severity Score (ISS) 20 pts). Major injuries were found in 3953 patients (26%). Minor injuries were documented in 11347 patients (74%). Of those patients with a major injury, 76% (2991 patients) suffered a fracture, 3% (132 patients) a dislocation and 3% (131 patients) an injury of nerves, tendons or ligaments. The majority of fractures were located in the upper extremity (73%) (elbow fractures 16%; radius fractures 16%; finger fractures 14%). Patients with minor injuries presented with head injuries (34%), finger injuries (10%) and injuries of the upper ankle (9%). The most common trauma mechanisms included impact (41%), followed by falls from standing height (24%), sport injuries (15%) and traffic accidents (9%). Overall, 1558 patients (10%) were operated. Of these, 61% had a major and 39% a minor injury.ConclusionAlmost 75% of all children, who presented to the emergency department following trauma revealed minor injuries. However, 25% suffered a relevant, major injury and 0.5% suffered a multiple trauma with a median ISS of 20. Overall, 10% had to be operated. The most frequently found major injuries were extremity fractures, with elbow fractures as the most common fracture.     

Is there a role of coral bone substitutes in bone repair?

Xenogeneic bone graft materials are an alternative to autologous bone grafting. Among such implants, coralline-derived bone grafts substitutes have a long track record as safe, biocompatible and osteoconductive graft materials. In this review, we present the available literature surrounding their use with special focus on the commercially available graft materials. Corals thanks to their chemical and structural characteristics similar to those of the human cancellous bone have shown great potential but clinical data presented to date is ambiguous with both positive and negative outcomes reported. Correct formulation and design of the graft to ensure adequate osteo-activity and resorption appear intrinsic to a successful outcome.     

What should we do as orthopedic surgeons in catastrophic disasters?

On March 11, 2011, Japan was consecutively hit by three unprecedented disasters caused by The Great East Japan (Tohoku) Earthquake: an earthquake of magnitude 9.0, an incredibly powerful tsunami, and a nuclear power plant breakdown. As Japan had experienced The Great Hanshin-Awaji Earthquake in 1995, we were prepared to provide the victims with appropriate medical care to some extent. Nevertheless, providing medical treatment after the Tohoku earthquake was extremely difficult due to the fact that the types of injuries in Tohoku were quite different from those in Hanshin. Based on our experiences in Hanshin and Tohoku, I would like to send a message to the world concerning the role of orthopedic surgeons in catastrophic disasters.     

Diagnosis and follow-up in constipated children: should we use ultrasound?

Purpose

We investigated the efficacy of ultrasound in determining megarectum and fecal load and the response to treatment in constipation and tried to specify objective criteria in this study.

Methods

A total of 66 cases were queried and divided into 2 groups as constipated (n = 35; mean age, 6.8 ± 2.9 years) and control (n = 31; mean age, 8.4 ± 3.8 years) according to Rome III criteria. After the clinical evaluation, pelvic ultrasonography (US) was performed by 2 separate radiologists. The bladder capacity and the transverse rectal diameter were measured with a full bladder. Then the rectal diameter and rectal anterior wall thickness were measured, and the presence of fecal load in the rectum and sigmoid colon was recorded with an empty bladder. The examination and ultrasound were repeated after treatment for a month in these patients.

Results

Comparison of the US measurements of the 2 radiologists performing the US tests did not show any interobserver difference (r = 0.981; P < .001). We therefore believe our results are objective and reproducible. We found a positive correlation between the rectal diameters and the age, height, weight, and bladder capacity. The posturination mean rectal diameter was thicker in the constipated group (3.02 ± 1.04 cm) than in the control group (1.98 ± 0.64 cm) (P < .001). The cutoff point of rectal diameter for a diagnosis of constipation was determined as 2.44 cm (71% sensitive; 76% specific; area under curve, 0.825; P < .001). The rectal anterior wall thickness and fecal load were higher in the constipated patients (P < .001). There was a significant decrease in the constipation score and fecal load after treatment for a month (P < .001), but the rectal diameter had not reached normal limits yet despite the decrease (2.71 ± 0.77 cm) (P > .05).

Conclusion

The use of US helps in making a correct diagnosis and in the follow-up with objective criteria and also convinces the patient and the family that the treatment needs to be continued.     

Small-for-size graft in living donor liver transplantation: How far should we go?

With the extensive use of living donor liver grafts in adult patients, controversy over small-for-size syndrome has escalated in recent years. Although several symptoms have been suggested as manifestations of the syndrome, small-for-size syndrome remains difficult to diagnose because these symptoms are neither specific nor inevitable. The occurrence of small-for-size syndrome also seems to depend on a number of recipient and graft factors. Potential pathogenic mechanisms include persistent portal hypertension and portal overperfusion. At present, several techniques are being explored in an attempt to ameliorate the impact of small-for-size syndrome. Recent experience suggests that the occurrence of small-for-size syndrome is multifactorial and that complications relating to small-for-size grafts should be examined in relation to a variety of graft, recipient, and technical factors. (Liver Transpl 2003;9:S29-S35.)