An Alternative Source of Autograft Bone for Spinal Fusion: the Femur: Technical Case Report

Fusion Revision Surgery With Reamer-Irrigator-Aspirator to Harvest Autograft After Spinal Pseudarthrosis

Background and purpose

Spinal pseudarthrosis (SPA) is a common complication after attempted cervical or lumbosacral spinal fusion surgery. Revision surgeries usually necessitate bone graft implementation as an adjunct to hardware revision. Iliac crest bone graft is the gold standard but availability can be limited and usage often leads to persistent postoperative pain at the donor site. There is scant literature regarding the use of reamer-irrigator-aspirator (RIA)-harvested bone graft in lumbar spinal fusion. This is a collaborative study between orthopedic surgery and neurosurgery departments to utilize femur intramedullary autograft harvested using the RIA system as an adjunct graft in SPA revision surgeries.

Materials and methods

A retrospective review was conducted at a single center between August 2014 and December 2017 of patients aged ≥ 18 years and diagnosed with cervical, thoracic, or lumbar SPA who underwent revision fusion surgery using femur intramedullary autograft harvested using the RIA system. Plain radiographs and CT scans were utilized to confirm successful fusion.

Results

Eleven patients underwent 12 SPA revision surgeries using the RIA system as a source for bone graft in addition to bone morphogenetic protein 2 (BMP-2) and allograft. The mean amount of graft harvested was 51.3 mL (range: 20-70 mL). Nine patients achieved successful fusion (81.8%). The average time to fusion was 9.1 months. Four patients (36.4%) had postoperative knee pain. Regarding patient position and approach for harvesting, 66.7% (n = 8) of cases were positioned prone and a retrograde approach was utilized in 91.7% (n = 11) of cases.

Interpretation

This is the first case series in known literature to report the RIA system as a reliably considerable source of autologous bone graft for SPA revision surgeries. It provides a useful adjunct to the known types of bone grafts. Patient positioning and the approach choice for graft harvesting can be adjusted according to the fusion approach and the surgeon’s preference.

Long-term posterolateral spinal fusion in rabbits induced by rhBMP6 applied in autologous blood coagulum with synthetic ceramics

Autologous bone graft substitute (ABGS) containing rhBMP6 in autologous blood coagulum (Osteogrow) is a novel therapeutic solution for bone regeneration. This study is aimed to investigate the long-term outcome of ABGS with synthetic ceramics (Osteogrow-C) in rabbit posterolateral spinal fusion (PLF) model. Osteogrow-C implants were implanted bilaterally between rabbit lumbar transverse processes. We compared the outcome following implantation of ABGS with ceramic particles of different chemical composition (TCP and biphasic ceramics containing both TCP and HA) and size (500–1700 µm and 74–420 µm). Outcome was analyzed after 14 and 27 weeks by microCT, histology, and biomechanical analyses. Successful bilateral spinal fusion was observed in all animals at the end of observation period. Chemical composition of ceramic particles has impact on the PLF outcome via resorption of TCP ceramics, while ceramics containing HA were only partially resorbed. Moreover, persistence of ceramic particles subsequently resulted with an increased bone volume in implants with small particles containing high proportion of HA. ABGS (rhBMP6/ABC) with various synthetic ceramic particles promoted spinal fusion in rabbits. This is the first presentation of BMP-mediated ectopic bone formation in rabbit PLF model with radiological, histological, and biomechanical features over a time course of up to 27 weeks.

Comparing the efficacy of syngeneic iliac and femoral allografts with iliac crest autograft in a rat model of lumbar spinal fusion

BACKGROUND

Despite widespread use of femoral-sourced allografts in clinical spinal fusion procedures and the increasing interest in using femoral reamer-irrigator-aspirator (RIA) autograft in clinical bone grafting, few studies have examined the efficacy of femoral grafts compared to iliac crest grafts in spinal fusion. The objective of this study was to directly compare the use of autologous iliac crest with syngeneic femoral and iliac allograft bone in the rat model of lumbar spinal fusion.

METHODS

Single-level bilateral posterolateral intertransverse process lumbar spinal fusion surgery was performed on Lewis rats divided into three experimental groups: iliac crest autograft, syngeneic iliac crest allograft, and syngeneic femoral allograft bone. Eight weeks postoperatively, fusion was evaluated via microCT analysis, manual palpation, and histology. In vitro analysis of the colony-forming and osteogenic capacity of bone marrow cells derived from rat femurs and hips was also performed to determine whether there was a correlation with the fusion efficacy of these graft sources.

RESULTS

Although no differences were observed between groups in CT fusion mass volumes, iliac allografts displayed an increased number of radiographically fused fusion masses and a higher rate of bilateral fusion via manual palpation. Histologically, hip-derived grafts showed better integration with host bone than femur derived ones, likely associated with the higher concentration of osteogenic progenitor cells observed in hip-derived bone marrow.

CONCLUSIONS

This study demonstrates the feasibility of using syngeneic allograft bone in place of autograft bone within inbred rat fusion models and highlights the need for further study of femoral-derived grafts in fusion.

Twelve-month results of a multicenter, blinded, pilot study of a novel peptide (B2A) in promoting lumbar spine fusion

OBJECT

Failure of fusion after a transforaminal lumbar interbody fusion (TLIF) procedure is a challenging problem that can lead to ongoing low-back pain, dependence on pain medication, and inability to return to work. B2A is a synthetic peptide that has proven efficacy in achieving fusion in animal models and may have a better safety profile than bone morphogenetic protein. The authors undertook this study to evaluate the safety and efficacy of B2A peptide-enhanced ceramic granules (Prefix) in comparison with autogenous iliac crest bone graft (ICBG, control) in patients undergoing single-level TLIF.

METHODS

Twenty-four patients with single-level degenerative disorders of the lumbar spine at L2-S1 requiring TLIF were enrolled between 2009 and 2010. They were randomly assigned to 3 groups: a control group (treated with ICBG, n = 9), a Prefix 150 group (treated with Prefix 150 μg/cm(3) granules, n = 8), and a Prefix 750 group (treated with Prefix 750 μg/cm(3) granules, n = 7). Outcome measures included the Oswestry Disability Index (ODI), visual analog pain scale, and radiographic fusion as assessed by CT and dynamic flexion/extension lumbar plain radiographs.

RESULTS

At 12 months after surgery, the radiographic fusion rate was 100% in the Prefix 750 group, 78% in the control group, and 50% in the Prefix 150 group, although the difference was not statistically significant (p = 0.08). At 6 weeks the mean ODI score was 41.0 for the control group, 27.7 for the Prefix 750 group, and 32.2 for the Prefix 150 group, whereas at 12 months the mean ODI was 24.4 for control, 31.1 for Prefix 750, and 29.7 for Prefix 150 groups. Complications were evenly distributed among the groups.

CONCLUSIONS

Prefix appears to provide a safe alternative to autogenous ICBG. Prefix 750 appears to show superior radiographic fusion when compared with autograft at 12 months after TLIF, although no statistically significant difference was demonstrated in this small study. Prefix and control groups both appeared to demonstrate comparable improvements to ODI at 12 months.

Sequential harvesting of bone graft from the intramedullary canal of the femur

The effectiveness of using the Reamer/Irrigator/Aspirator (RIA) System (Synthes, Inc, West Chester, Pennsylvania) to obtain bone graft from the intramedullary canal of long bones for the treatment of bone defects and nonunions has been previously documented. However, there is nothing in the literature discussing the potential for reaming the same canal at subsequent surgeries. The authors detail their experience of 8 instances of sequential reaming in 7 patients. Six patients were harvested twice, and 1 patient was harvested 3 times. In each patient, the bone graft was obtained from the same canal. The main outcome measurements were time interval between reamings, reamer head size, indication for reaming, volume of harvested bone graft, and complications. Average volume of graft obtained in the first reaming procedure was 34 mL (range, 25-50 mL). After an average of 9 months (range, 3-16 months), the subsequent reaming was performed. Average volume of graft obtained in the second procedure was 45 mL (range, 28-65 mL). In the authors' series, no reaming-related complications were observed. The graft volume was the same or increased during the subsequent intramedullary reaming in all but 1 case, suggesting that the intramedullary canal is a potentially renewable source for bone graft. There were no complications related to the sequential reaming procedure. Overall, the authors' data suggest that sequential reaming with the RIA has the potential to safely and effectively provide a large quantity of bone graft on multiple occasions.

Donor site morbidity with reamer-irrigator-aspirator (RIA) use for autogenous bone graft harvesting in a single centre 204 case series

Donor site morbidity and complication rate using the reamer-irrigator-aspirator (RIA) system for intramedullary, non-structural autogenous bone graft harvesting were investigated in a retrospective chart and radiographic review at a University affiliated Level-1 Trauma Centre. 204 RIA procedures in 184 patients were performed between 1/1/2007 and 12/31/2010. RIA-indication was bone graft harvesting in 201 (98.5%), and intramedullary irrigation and debridement in 3 (1.5%) cases. Donor sites were: femur - antegrade 175, retrograde 4, tibia - antegrade 7, retrograde 18. Sixteen patients had undergone two RIA procedures, two had undergone three procedures, all using different donor sites. In 4 cases, same bone harvesting was done twice. Mean volume of bone graft harvested was 47 ± 22ml (20-85 ml). The complication rate was 1.96% (N=4). Operative revisions included 2 retrograde femoral nails for supracondylar femur fractures 6 and 41 days postoperatively (antegrade femoral RIA), 1 trochanteric entry femoral nail (subtrochanteric fracture) 17 days postoperatively (retrograde femoral RIA) and 1 prophylactic stabilization with a trochanteric entry femoral nail for intraoperative posterior femoral cortex penetration without fracture. In our centre, the RIA technique has a low donor site morbidity and has been successfully implemented for harvesting large volumes of nonstructural autogenous bone graft.

Complications following autologous bone graft harvesting from the iliac crest and using the RIA: a systematic review

Bone grafting is a commonly performed surgical procedure to augment bone regeneration in a variety of cases in orthopaedic and maxillofacial surgery. Autologous bone graft remains to be the 'gold standard' and the iliac crest to be the most common harvesting site. The intramedullary canal of long bones represents another potential site for large volume of autologous bone graft harvesting and is recently being used as an alternative donor site. However, harvesting of autologous bone graft is associated with morbidity and a number of complications. The aim of this systematic review was to collect and summarise the existing data on reported complications after harvesting autologous bone from the iliac crest (anterior and posterior) and the long bone intramedullary canal using the RIA device. We searched the PubMed Medline and Ovid Medline databases, from January 1990 to October 2010, to retrieve all relevant articles. A total of 92 articles (6682 patients) were included in the analysis. Overall, the complication rate following RIA was 6% (14 complications in 233 patients) and 19.37% after iliac crest bone graft harvesting (1249 complications in 6449 patients). The rate of each of the reported complications was assessed and, when the donor site was properly documented, comparison within the anterior and posterior iliac crest donor sites was performed. Although the difference of the overall morbidity rates between the two harvesting sites was not statistically significant (p=0.71); the rates of certain complications were found to significantly differ when anterior or posterior iliac crest was used. The rates of infection (p=0.016), haematoma formation (p=0.002), fracture (p=0.017), and hyperthrophic scar (p=0.017) were significantly higher when the donor site was the anterior iliac crest compared to the posterior iliac crest; whereas the rates of chronic donor site pain (p=0.004) and sensory disturbances (p=0.003) were significantly lower. The incidence of bone graft harvesting related complications can be reduced further if certain principles are followed depending on the performed harvesting methods; but overall the use of RIA device as harvesting method seems a promising alternative with a low complication rate.

Reaming Irrigator Aspirator system: early experience of its multipurpose use

The evolution of contemporary intramedullary reaming systems has recently generated the Reamer Irrigator Aspirator system (RIA-Synthes®), which has progressively gained in popularity as well as in indications. The preliminary results of its use over the initial period of 18 months ata single tertiary referral centre were prospectively collected and are presented. The wide spectrum of RIA's indications have been exploited, including 7 patients with polytrauma that underwent acute femoral nailing, 8 with femoral intramedullary osteomyelitis, 9 with pathological lesions of the femoral shaft, as well as 18 patients where the RIA system has been used to harvest morselised autologous bone graft in the presence of recalcitrant atrophie non-unions and bone defects. Overall its use was proven safe and efficient, achieving aggressive medullary canal debridement, collection of adequate samples for further analysis in the infected and oncology cases, as well as impressive volumes of the osteoinductive and osteogenic reaming debris for grafting purposes. No pulmonary complications or evidence of the second hit sequelae were recorded in the polytrauma patient subgroup despite the presence of a high ISS Further controlled clinical studies should follow focused in all different applications of this reliable, user-friendly and impressively versatile system, to validate these preliminary results.

Risk of graft fracture after dorso-ventral thoraco-lumbar spondylodesis: is there a correlation with graft size?

STUDY DESIGN

Retrospective clinical study in patients with dorso-ventral thoraco-lumbar spondylodesis.

OBJECTIVE

To investigate whether the ratio between graft cross sectional area and the surface area of the adjacent endplates has any effect on the midterm stability of the spondylodesis. Dorso-ventral spondylodesis in the region of the thoraco-lumbar spine is one of the most frequent operations in orthopaedic surgery. Anterior stabilization with autologous iliac crest graft currently is a standard approach in many hospitals. Although numerous recommendations are given how to perform this technique, no clinical advice is available with regard to minimum graft size.

METHODS

Sixty-four-slice CT-scans were obtained from 82 patients 4-12 months after posterior spondylodesis with anterior implantation of iliac crest graft and stabilization with an internal fixator. The scans were analyzed using image analysis software. First, the cross sectional area of the graft was calculated and then the surface area of the adjacent endplates. The ratio between graft cross sectional area and endplate surface area was then calculated from these two values. The grafts were then evaluated in sagittal reconstruction for signs of fracture.

RESULTS

The probability for graft fracture in autologous tricortical grafts was >0.1% (p < 0.001) if the graft cross sectional area exceeded 23.9% of the surface area of the adjacent endplates. Patients with lower ratio values had a higher fracture risk and below a value of 10% all grafts fractured.

CONCLUSION

The relationship between graft cross sectional area and adjacent endplate area has an important effect on graft midterm stability in ventral spondylodesis of the thoraco-lumbar spine. In our opinion, the risk of graft fractures in dorso-ventral spondylodesis can be reduced by implantation of an appropriately sized graft without any additional procedures or instrumentation.

Bone graft harvesting using the RIA (reaming irrigation aspirator) system - a quantitative assessment

INTRODUCTION

Autologous bone graft is still considered to be the gold standard for treating non-unions in trauma and orthopedic surgery. Intramedullary bone graft harvest appears to be an alternative to other bone graft options such as iliac crest bone graft and synthetic bone substitutes. A one-step reamer-irrigator-aspirator (RIA) system has been developed to reduce the intramedullary pressure and, as a consequence, minimize the risk of fat embolization. The purpose of this study was to determine whether the quantity of harvested intramedullary bone graft is comparable to the quantity of graft that was harvested from the iliac crest in other studies. The aim of the present study was to quantify harvested bone marrow and to compare our results to already published data.

METHODS

Eight human cadavers (7 males, 1 female, and 16 limbs) with an average age of 68 years (range, 49-79 years) were obtained for this study. Intramedullary reaming was performed in the tibiae and femora of each cadaver. Two different sizes (12- and 14-mm diameter) of the RIA system were used. After a medial parapatellar incision was made at the knee, antegrade and retrograde reaming were performed in the tibiae and femur to harvest bone graft.

RESULTS

A significantly greater quantity of bone graft was harvested from the femora (27 ± 12 g) than the tibiae (17 ± 9 g) (p = 0.007).

CONCLUSIONS

On the basis of our present results, harvesting intramedullary bone graft with the RIA system appears to be an innovative technique for bone grafting in limb reconstruction. A significantly greater quantity of bone graft was harvested from the femora than the tibiae (p = 0.007). No significant differences among age, sex, body weight, bone length, or BMI were observed. Our results showed that a sufficient quantity in weight of autogenous bone graft could be obtained using the RIA system.

[Radiological comparison between two procedures for ventral spondylodesis: autologous iliac crest bone graft vs bovine bone graft]

BACKGROUND

The objective of this study was the radiological evaluation of osseous integration of autologous iliac crest graft and bovine bone graft after spondylodesis based on a standardized score.

MATERIAL AND METHODS

Spondylodesis was performed on 18 sheep, divided into 2 groups, 1 with an autologous iliac crest graft and the other with a bovine bone graft. Computed tomography was performed 12 and 24 weeks postoperatively. The osseous integration was assessed by the Tübinger Score.

RESULTS

The evaluation of the CT scans demonstrated a significantly better osseous integration of the autologous iliac crest graft compared to the bovine bone graft.

CONCLUSIONS

Based on our results, the bovine bone graft as a transplant for spondylodesis is inadvisable.

Reamer-irrigator-aspirator indications and clinical results: a systematic review

BACKGROUND

The 'reamer-irrigator-aspirator' (RIA) is an innovation developed to reduce fat embolism (FE) and thermal necrosis (TN) that can occur during reaming/nailing of long-bone fractures. Since its inception its indications have expanded to include the treatment of long-bone osteomyelitis and as a harvester of bone graft/mesenchymal stem cells (MSCs).

METHODS

This study involved a systematic review, via Pubmed® and Google Scholar®, of English language sources (nine non-clinical studies, seven clinical studies and seven case reports) using the keywords: 'reamer', 'irrigator', 'aspirator' (1st May 2010). Sources were reviewed with reference to the RIAs efficacy in (1) preventing FE/TN, (2) treating long-bone osteomyelitis, (3) harvesting bone graft/MSCs, and (4) operating safely. Experimental data supports the use of the RIA in preventing FE and TN, however, there is a paucity of clinical data.

CONCLUSIONS

The RIA is a reliable method in achieving high volumes of bone graft/MSCs, and high union rates are reported when using RIA bone-fragments to treat non-unions. Evidence suggests possible effectiveness in treating long-bone osteomyelitis. The RIA appears relatively safe, with a low rate of morbidity provided a meticulous technique is used. When complications occur they respond well to conventional techniques. The RIA demands further investigation especially with respect to the optimal application of MSCs for bone repair strategies.

Autogenous bone graft harvest using reamer irrigator aspirator (RIA) technique for tibiotalocalcaneal arthrodesis

Tibiotalocalcaneal arthrodesis is a technically demanding procedure that can be associated with a high number of complications, including nonunion. Bone grafting is commonly used in arthrodesis procedures to decrease the risk of nonunion. In this article, we describe a technique that uses a reamer-irrigator-aspirator (RIA) method for procurement of autogenous bone graft for use in tibiotalocalcaneal arthrodesis fixated with a retrograde intramedullary nail. Using the RIA technique, autogenous bone graft can be readily obtained without the need for additional incisions and dissection, thereby minimizing the need for additional sources of bone graft.

Effect of graft size on graft fracture rate after anterior lumbar spinal fusion in a sheep model

STUDY DESIGN

Sheep anterior spinal fusion model with autogenous and xenogenous bone grafts.

OBJECTIVE

To investigate whether the relationship between cross-sectional area of the bone graft and area of the adjacent vertebral endplates has an effect on graft fracture rate.

SUMMARY OF BACKGROUND DATA

Anterior spondylodesis with autogenous iliac crest transplant is a frequently performed operation to stabilize spinal motion segments but to date no precise recommendations with respect to minimum graft size are available in the literature.

METHODS

Anterior spondylodesis using autogenous and xenogenous grafts of constant size in combination with an angular stable plate (Macs TL). Autogenous iliac crest graft was inserted in eight sheep and xenogenic, commercially available bovine graft (Tutobone) in the additional eight animals. The surface areas of the endplates of the fused intervertebral space were calculated using CT scans and contact radiographs of the specimens obtained after 24 weeks. The graft itself was evaluated for fractures and osteolysis.

RESULTS

A fracture occurred in tricortical, autogenous grafts if the graft cross-sectional area was less than 21% of the area of the adjacent endplates. All xenogenic grafts fractured and therefore a comparable value could not be determined.

CONCLUSION

The results clearly indicate that the relation between graft cross-sectional area and endplate area defines the survival or fracture of the graft in anterior spinal fusion. Although it is difficult to directly apply the results to the clinical situation it is suggested to choose a sufficiently large graft, in order to reduce the risk of autogenous graft fracture in anterior spondylodesis.

Managing bone deficiency and nonunions of the proximal femur

Revision surgery of the proximal femur with bone loss secondary to failed cephalomedullary nails is problematic and becoming more prevalent as their use grows. This article presents a technique of deformity correction, bone graft techniques that reconstitute residual defects, and definitive fixation using load-sharing devices that provide immediate stability for bone healing and early rehabilitation. Preoperative planning and the potential advantages and disadvantages of newer fixed-angled plates versus established implants are discussed. With proper planning, surgical execution with proved techniques, augmented by the addition of newer graft harvesting techniques, anatomic restoration, and bone reconstitution with healing, has invariably been the result.

Autograft and nonunions: morbidity with intramedullary bone graft versus iliac crest bone graft

This article focuses on comparing patient morbidity with harvesting bone graft for the treatment of nonunions from three different sites. Anterior iliac crest graft is the most commonly used site; however, the posterior iliac crest and intramedullary canal provide greater quantities of bone. The anterior and posterior iliac crests also have some donor site complications such as nerve injury and persistent pain. The intramedullary canal, when compared with anterior and posterior iliac crest, offers the largest quantity of bone graft with the least amount of patient donor site morbidity. The intramedullary canal also appears to be a bone graft source that can be reharvested, unlike the anterior and posterior iliac crest donor sites.

Surgical techniques: how I do it? The Reamer/Irrigator/Aspirator (RIA) system

Although reamed intramedullary nailing has long been considered a safe procedure, pulmonary complications have been reported in some groups of patients. Concerns over fat embolisation, adult respiratory distress syndrome (ARDS), and sudden intraoperative death have prompted some authors to question whether the benefits of reaming are outweighed by its potential adverse effects to the patient. In response to these complications, recent evaluations have focused on alternative systems that reduce intramedullary pressure during reaming. The Reamer/Irrigator/Aspirator (RIA) system (Synthes, Inc., West Chester, PA) was developed as a simultaneous reaming and aspiration system to reduce the intramedullary pressure, heat generation, operating time, and systemic effects of reaming. It was designed with an aggressive one-pass reamer head which is connected to a hand-held reamer via a drive shaft, simultaneously irrigating and aspirating femoral canal contents during reaming, thus preventing thermal necrosis and fat embolisation. After its early use, investigators examined the "aspirate" captured by the RIA which appeared to be loaded with osteogenic substrates. This discovery revealed a second potential use for the RIA-a bone graft harvester. The different design characteristics and technicalities of the RIA system necessitate a deep and clear understanding of its technique, a meticulous preoperative planning and a strict adherence to its principles intraoperatively. We present our current approach to the use of the RIA system, including the preoperative planning, the details of the operative procedure, the pitfalls and the potential complications that could be encountered.

Bone graft harvest using a new intramedullary system

Obtaining autogenous bone graft from the iliac crest can entail substantial morbidity. Alternatively, bone graft can be harvested from long bones using an intramedullary (IM) harvesting system. We measured bone graft volume obtained from the IM canals of the femur and tibia and documented the complications of the harvesting technique. Donor site pain and the union rate were compared between the IM and the traditional iliac crest bone graft (ICBG) harvest. Forty-one patients (23 male, 18 female) with an average age of 44.9 years (range, 15-78 years) had graft harvested from long bones using an IM harvest system (femoral donor site, 37 patients; tibial donor site, four patients). Forty patients (23 male, 17 female; average age, 46.4 years; range, 15-77 years) underwent anterior ICBG harvest. We administered patient surveys to both groups to determine pain intensity and frequency. IM group reported lower pain scores than the ICBG group during all postoperative periods. Mean graft volume for the IM harvest group was 40.3 mL (range, 25-75 mL) (graft volume was not obtained for the ICBG group). Using an intramedullary system to harvest autogenous bone graft from the long bones is safe provided a meticulous technique is used.

LEVEL OF EVIDENCE

Level III, retrospective comparative study. See the Guidelines for Authors for a complete description of levels of evidence.

Innovations in osteosynthesis and fracture care

Over the years giant steps have been made in the evolution of fracture fixation and the overall clinical care of patients. Better understanding of the physiological response to injury, bone biology, biomechanics and implants has led to early mobilisation of patients. A significant reduction in complications during the pre-operative and post-operative phases has also been observed, producing better functional results. A number of innovations have contributed to these improved outcomes and this article reports on the advances made in osteosynthesis and fracture care.