Orthopedics

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Trauma Update 

A New Minimally Invasive Technique for Large Volume Bone Graft Harvest for Treatment of Fracture Nonunions

Justin T. Newman, MS; Philip F. Stahel, MD; Wade R. Smith, MD; Gustavo V. Resende, MD; David J. Hak, MD; Steven J. Morgan, MD

Abstract

Autologous Reamer-Irrigator-Aspirator bone grafting represents a safe and efficient procedure to treat fracture nonunions of long bones.

Traditional techniques for harvesting autologous iliac crest bone graft often yield less than adequate amounts of bone graft. When an insufficient quantity of iliac crest bone graft is obtained, additional harvest sites need to be used, thereby increasing the risk of local donor site morbidity.1 Alternatively, autologous graft may be extended with allogeneic bone. However, the use of allograft sources incurs the risk of infection, which, along with the lack of osteoinductive potential, remains a major pitfall in the treatment of nonunions and segmental defects.

The Reamer-Irrigator-Aspirator (Synthes, Paoli, Pennsylvania) is an intramedullary reaming system, conceptualized to collect and evacuate marrow contents during reaming to prevent their embolization into the systemic circulation. The Reamer-Irrigator-Aspirator system was designed to ream the intramedullary canal in a single step prior to placement of an intramedullary nail for the fixation of long bone fractures. As the head of the Reamer-Irrigator-Aspirator reams the contents from the medullary canal, fluid is introduced into the canal that suspends the reamed material and cools the cortical bone (Figure 1). The reamer head design then forces this by-product to the rear of the reamer. An auger on the reamer shaft further moves the marrow contents away from the reamer head. The reamed contents subsequently enter a negative pressure environment that facilitates removal of the contents from the intramedullary canal. Thus, a large volume of corticocancellous bone material is generated in a single step reaming process and can be evacuated and potentially used as an autologous bone graft source (Figure 2).

The technique of collecting and applying the aspirated contents from the medullary canal has potential to treat fracture nonunions and segmental bone defects that may require large volumes of autologous bone graft to stimulate healing in a mechanically favorable environment. A further benefit of Reamer-Irrigator-Aspirator is that the autologous bone harvest can be performed with a minimally invasive technique, thus limiting donor site morbidity. Further investigation into the use of the Reamer-Irrigator-Aspirator for this purpose is necessary.2 This article describes the technique of Reamer-Irrigator-Aspirator bone graft harvest and presents preliminary data on a pilot study in 10 patients with fracture nonunions.

Reaming of the femoral canal and collection of bone marrow contents is performed with the Reamer-Irrigator-Aspirator device. The patient is positioned either supine or prone on a radiolucent table. Preoperative planning is required to select the correct reamer head size. An image of the isthmus of the femur is obtained and a ruler guide is placed over this area to determine the size of the narrowest point of the canal. Magnification of the intensifier should be taken in to account, and a reamer head is selected that is 1 to 4 mm greater than the narrowest part of the canal. The smallest available reamer head in the Reamer-Irrigator-Aspirator system is 12 mm. Intraoperative fluoroscopy is required to visualize the starting point for femoral canal entry, and the extent of reaming. Images of the entire femur must be obtained during the procedure.

Harvest of femoral canals <10 mm in diameter may be contraindicated based on our experience with femoral reaming for intramedullary nail placement secondary to the potential for reamer incarceration and difficulty in advancement of the reamer. Conversely, the largest reamer head in the system is 16.5 mm, and large diameter canals or canals with excessively thin cortices may not yield adequate graft even with the largest reamer head. In either case, excessively small or large diameter canals may contraindicate Reamer-Irrigator-Aspirator bone graft harvest. Once the appropriate reamer diameter is selected,…

Autologous Reamer-Irrigator-Aspirator bone grafting represents a safe and efficient procedure to treat fracture nonunions of long bones.

Traditional techniques for harvesting autologous iliac crest bone graft often yield less than adequate amounts of bone graft. When an insufficient quantity of iliac crest bone graft is obtained, additional harvest sites need to be used, thereby increasing the risk of local donor site morbidity.1 Alternatively, autologous graft may be extended with allogeneic bone. However, the use of allograft sources incurs the risk of infection, which, along with the lack of osteoinductive potential, remains a major pitfall in the treatment of nonunions and segmental defects.

The Reamer-Irrigator-Aspirator (Synthes, Paoli, Pennsylvania) is an intramedullary reaming system, conceptualized to collect and evacuate marrow contents during reaming to prevent their embolization into the systemic circulation. The Reamer-Irrigator-Aspirator system was designed to ream the intramedullary canal in a single step prior to placement of an intramedullary nail for the fixation of long bone fractures. As the head of the Reamer-Irrigator-Aspirator reams the contents from the medullary canal, fluid is introduced into the canal that suspends the reamed material and cools the cortical bone (Figure 1). The reamer head design then forces this by-product to the rear of the reamer. An auger on the reamer shaft further moves the marrow contents away from the reamer head. The reamed contents subsequently enter a negative pressure environment that facilitates removal of the contents from the intramedullary canal. Thus, a large volume of corticocancellous bone material is generated in a single step reaming process and can be evacuated and potentially used as an autologous bone graft source (Figure 2).

The technique of collecting and applying the aspirated contents from the medullary canal has potential to treat fracture nonunions and segmental bone defects that may require large volumes of autologous bone graft to stimulate healing in a mechanically favorable environment. A further benefit of Reamer-Irrigator-Aspirator is that the autologous bone harvest can be performed with a minimally invasive technique, thus limiting donor site morbidity. Further investigation into the use of the Reamer-Irrigator-Aspirator for this purpose is necessary.2 This article describes the technique of Reamer-Irrigator-Aspirator bone graft harvest and presents preliminary data on a pilot study in 10 patients with fracture nonunions.

Technique

Reaming of the femoral canal and collection of bone marrow contents is performed with the Reamer-Irrigator-Aspirator device. The patient is positioned either supine or prone on a radiolucent table. Preoperative planning is required to select the correct reamer head size. An image of the isthmus of the femur is obtained and a ruler guide is placed over this area to determine the size of the narrowest point of the canal. Magnification of the intensifier should be taken in to account, and a reamer head is selected that is 1 to 4 mm greater than the narrowest part of the canal. The smallest available reamer head in the Reamer-Irrigator-Aspirator system is 12 mm. Intraoperative fluoroscopy is required to visualize the starting point for femoral canal entry, and the extent of reaming. Images of the entire femur must be obtained during the procedure.

Figure 1: Schematic drawing of the Reamer-Irrigator-Aspirator system
Figure 1: Schematic drawing of the Reamer-Irrigator-Aspirator system (Synthes, Paoli, Pennsylvania) and its functional parts. Irrigation (blue arrows) enters the reamer and subsequently the medullary canal from the distal aspect of the reamer. The irrigation and suspended debris are then aspirated (pink arrows). Details show the enlarged image of the head of the reamer (1) and of the irrigation-aspiration system in the proximal part (2).

Harvest of femoral canals <10 mm in diameter may be contraindicated based on our experience with femoral reaming for intramedullary nail placement secondary to the potential for reamer incarceration and difficulty in advancement of the reamer. Conversely, the largest reamer head in the system is 16.5 mm, and large diameter canals or canals with excessively thin cortices may not yield adequate graft even with the largest reamer head. In either case, excessively small or large diameter canals may contraindicate Reamer-Irrigator-Aspirator bone graft harvest. Once the appropriate reamer diameter is selected, the disposable reamer head is opened for one-time use and assembled per the manufacturer’s instructions. A Biomet Redi-Flow Fine Filter System (Warsaw, Indiana) is placed in line with the outflow portal of the Reamer-Irrigator-Aspirator system as a collection point for the intramedullary cortical cancellous contents during the reaming process.

With the Reamer-Irrigator-Aspirator fully assembled and the filter attached, the entry site for femoral reaming is identified under fluoroscopic control. Either a piriformis or greater trochanteric entry point may be used. A 3.2-mm Kirschner wire is inserted percutaneously, and a 13-mm cannulated reamer is used to open the proximal femoral canal to the level of the lesser trochanter. The reamer and the guide wire are removed. A 2.0-mm beaded-tip guide wire for the Reamer-Irrigator-Aspirator system is then inserted in the femoral canal to the level of the superior border of the patella. The guide wire is positioned concentrically in the intramedullary canal to prevent eccentric reaming, which may represent a severe complication due to the nature of the Reamer-Irrigator-Aspirator cutting flutes and the large diameter of the reamer head. Anteroposterior and lateral views must be obtained to verify positioning of the guide wire. The Reamer-Irrigator-Aspirator is then inserted over the guide wire and the femoral canal is entered with irrigation and aspiration functioning. A deliberate, progressive, pulsatile advancement of the reamer is used under C-arm guidance by advancing the reamer 1 to 2 cm distally and then withdrawing approximately half this distance to allow the irrigation to remove the particulate debris. Bone graft may be harvested from the proximal metaphyseal region, diaphysis, and distal metaphyseal region. After the reamer has been passed down and back out of the femoral canal, the filter should be checked, and the bone graft material should be removed to avoid overfilling the filter system with excessive graft material (Figure 2A).

Figure 2A: Reamer-Irrigator-Aspirator inline filter
Figure 2B: example of the quantity and consistency of the autologous graft obtained by a one-pass RIA bone graft harvest
Figure 2: Reamer-Irrigator-Aspirator (RIA; Synthes, Paoli, Pennsylvania) inline filter (A) and example of the quantity and consistency of the autologous graft obtained by a one-pass RIA bone graft harvest (B).

The volume of graft obtained depends on the size of the reamer head selected and its relationship to the femoral canal size. Although the amount of graft harvest may vary, overreaming the canal by 1 to 2 mm will generally produce between 60 and 80 mL of graft (Figure 2B). If more bone graft is required, the reamer system can be passed a second time. Increasing reamer sizes results in more of the graft being comprised of cortical bone. The autologous Reamer-Irrigator-Aspirator graft can then be applied to any osseous defect.

Clinical Pilot Study

Patients

After obtaining an institutional review board approval, a prospective database was retrospectively analyzed to identify patients who had undergone a Reamer-Irrigator-Aspirator bone graft procedure. From January 2005, to August 2007, 10 Reamer-Irrigator-Aspirator bone graft harvesting procedures were performed in 10 patients at our institution. All patients presented to our clinic with a fracture nonunion. Bone graft was harvested by Reamer-Irrigator-Aspirator procedure if the treating surgeon determined that this was the best option for the individual patient. The indications included a lack of other adequate sources of autologous bone graft (eg, in the case where iliac crest sites had been previously harvested), as well as individual patients’ preference after detailed consent regarding the experimental nature of the study and the current lack of evidence-based data on a potential benefit of Reamer-Irrigator-Aspirator bone grafting for nonunions.

The retrospective chart review of these patients was performed to collect outcome variables, including mechanism of injury, fracture classification, initial treatment, previous revision surgeries (eg, bone grafting), the location and classification of the nonunion, and the presence or absence of infection. Outcome measures included radiological and clinical fracture healing, time to healing, and complications. Clinical union was defined as absence of pain at the fracture site with direct palpation and cantilevered stress with full weight bearing. Radiographic union was defined as a minimum of 3 bridging cortices across the fracture site in anteroposterior, lateral, and oblique views. Nonunion was defined as persistence of an unhealed fracture at 6 months.

Results

All patients had a minimum of 8 months follow-up from the Reamer-Irrigator-Aspirator grafting procedure (range, 8-15 months). Mean time from the initial injury until Reamer-Irrigator-Aspirator bone grafting was 14 months (range, 2.5-32 months). Anatomic locations included the humerus shaft (n=1), tibia shaft (n=4), and femur shaft (n=5). Six patients had undergone a prior revision procedure to achieve union, and 4 patients were presenting with nonunion for the first time. Detailed patient demographics are presented in the Table. Nine of 10 patients treated by Reamer-Irrigator-Aspirator bone grafting achieved clinical union of their nonunions (Figure 3). One patient continued to have persistent nonunion and has subsequently undergone another procedure. All patients tolerated the Reamer-Irrigator-Aspirator procedure well, and no intra- or postoperative complications occurred. The only minor complication at the bone graft donor site was an asymptomatic hypertrophic scar formation at the lateral skin incision over the hip in 1 patient.

Figure 2A: Reamer-Irrigator-Aspirator inline filter
Figure 3B: Radiograph taken 6 months after revision surgery
Figure 3C:  Radiograph taken 1 year after revision surgery
Figure 3: Clinical example of Reamer-Irrigator-Aspirator (Synthes, Paoli, Pennsylvania) bone grafting for an atrophic femoral nonunion. A 20-year-old man sustained a type IIIB open left segmental femur fracture, associated with an ipsilateral femoral neck fracture and both column acetabular fracture. During the initial phase of surgery, the patient was resuscitated, the femoral neck fracture was managed by open reduction and cannulated screw fixation, and the segmental femur fracture was treated by a bridging submuscular plate. Approximately 12 weeks postoperatively, the patient demonstrated no evidence of healing of the left femur fracture (A). Revision plate fixation and autologous RIA bone grafting were performed. Radiographs taken 6 months (B) and 1 year (C) after revision surgery show a healed fracture with strong callus formation.

Discussion

Bone defects and fracture nonunions are challenging conditions that require surgical revision fixation and—in cases of atrophic or oligotrophic nonunion—an autologous bone grafting. Donor site complications associated with iliac crest bone graft harvesting are frequent and significant.1 We therefore tested an alternative, minimally invasive, graft harvest technique that provides a large volume of autologous bone graft. We hypothesized Reamer-Irrigator-Aspirator bone graft harvesting to be a safe and efficient procedure with decreased donor site complications, compared with iliac crest graft harvesting.

In this pilot study, Reamer-Irrigator-Aspirator bone grafting achieved a high rate of union with a low complication rate. The Reamer-Irrigator-Aspirator graft demonstrated effective in vivo biologic activity by forming bone and progressing to union in the majority of cases (Figure 3). Previous studies have revealed that human reaming debris has excellent bioactive osteogenic properties.2-5 The in vitro analysis of human reaming debris demonstrated the presence of pluripotent stem cells with a potential for growth, proliferation, and differentiation along the osteogenic pathway. These findings have prompted interest in the use of reaming debris-derived stem cells in cell and bone replacement therapies as a source of mesenchymal stem cells as well as supporting their use as an autologous graft.4,5

Table: Descriptive Data of the 10 Patients Included in the Pilot Study

Donor site morbidity after iliac bone harvesting represents a significant problem in orthopedic surgery. Minor complications have been reported in 9% to 39% and major complications in 0.76% to 25% of all cases.6,7 Minor complications included chronic pain, hematoma, seroma, infection, aesthetic problems, and iatrogenic neurological injuries to the lateral cutaneous nerve of the thigh. Major complications included a disruption of pelvic ring stability and infected nonunion of the pelvis, as recently reported by Oakley et al.1 Silber et al8 reported chronic donor site pain in 26% of patients after anterior iliac crest bone harvest for a single level anterior cervical fusion.8 In a study by Goulet et al,9 38% of patients reported persisting pain at 6 months postoperatively.

In contrast to these significant complications associated with a classical approach of autologous bone graft harvest, the minimally invasive (percutaneous) approach for Reamer-Irrigator-Aspirator bone graft harvesting appeared to decrease the incidence and relevance of donor site morbidity. No patients in the present pilot study required analgesic medication for donor site pain within 6 weeks after surgery.

No major complications from the harvest process were noted in the present series. However, reaming of the femoral canal is associated with a number of potential complications, including the potential for iatrogenic fractures of the proximal femur and femoral neck. Given that Reamer-Irrigator-Aspirator represents a relatively stiff one-pass reamer, careful initial sizing of the femoral canal is critical to ensure that a large enough reamer is passed to maximize graft harvest, while at the same time avoiding an oversized reamer, which may induce an iatrogenic fracture. Other potential problems include mechanical equipment failures, such as incarcerated or broken reamer heads. For this reason, the Reamer-Irrigator-Aspirator reamer should never be passed through the femoral canal without the use of a guide wire, which may serve as a salvaging tool to retrieve an incarcerated reamer. A systemic complication of femoral reaming includes fat embolism syndrome and acute respiratory distress syndrome. The embolization of fat and marrow products and subsequent decreases in pulmonary function with reaming is well documented.10 Compared with conventional reamers, the Reamer-Irrigator-Aspirator system appeared to reduce the extent of bone marrow extravasation due to the concept of intramedullary negative-pressure aspiration11-13 and to reduce cortical heat generation through intramedullary irrigation.14 These important properties may lead to a decreased incidence of pulmonary complications by Reamer-Irrigator-Aspirator one-pass reaming, as opposed to conventional reaming techniques.

Limitations of the present study include the small sample size from a single center and the retrospective nature of data analysis. This was an unfunded pilot study intended to evaluate the biologic efficacy and safety of this technique in a small series of patients who were unwilling or unable to undergo iliac crest bone grafting. Stafford2 described better tolerance of the Reamer-Irrigator-Aspirator graft harvesting procedure when the graft was obtained from the contralateral side for lower and upper extremity graft sites. In contrast, the present study demonstrated that ipsilateral bone graft harvesting for tibial nonunions is well tolerated. This has the benefit of ipsilateral prepping and draping of only one lower extremity and spares the patient a surgical procedure on bilateral lower extremities.

Conclusion

Autologous Reamer-Irrigator-Aspirator bone grafting represents a safe and efficient procedure to treat fracture nonunions of long bones. This minimally invasive technique is associated with a low rate of donor site morbidity and a low rate of intra- and postoperative complications. Future prospective studies are needed to verify the scientific value of these promising preliminary results.

References

  1. Oakley MJ, Smith WR, Morgan SJ, Ziran NM, Ziran BH. Repetitive posterior iliac crest autograft harvest resulting in an unstable pelvic fracture and infected nonunion: case report and review of the literature. Patient Safety in Surgery. 2007; 1:6.
  2. Stafford PR, Norris B. Reamer-irrigator-aspirator as a bone graft harvester. Techniques Foot Ankle Surg. 2007; 6:100-107.
  3. De Long WG Jr, Einhorn TA, Koval K, et al. Bone grafts and bone graft substitutes in orthopaedic trauma surgery. A critical analysis. J Bone Joint Surg Am. 2007; 89(3):649-658.
  4. Wenisch S, Trinkaus K, Hild A, et al. Human reaming debris: a source of multipotent stem cells. Bone. 2005; 36(1):74-83.
  5. Trinkaus K, Wenisch S, Siemers C, Hose D, Schnettler R. Reaming debris: a source of vital cells! First results of human specimens [German]. Unfallchirurg. 2005; 108(8):650-656.
  6. Banwart JC, Asher MA, Hassanein RS. Iliac crest bone graft harvest donor site morbidity. A statistical evaluation. Spine. 1995; 20(9):1055-1060.
  7. Arrington ED, Smith WJ, Chambers HG, Bucknell AL, Davino NA. Complications of iliac crest bone graft harvesting. Clin Orthop Relat Res. 1996; 329:300-309.
  8. Silber JS, Anderson DG, Daffner SD, et al. Donor site morbidity after anterior iliac crest bone harvest for single-level anterior cervical discectomy and fusion. Spine. 2003; 28(2):134-139.
  9. Goulet JA, Senunas LE, DeSilva GL, Greenfield ML. Autogenous iliac crest bone graft.Complications and functional assessment. Clin Orthop Relat Res. 1997; 339:76-81.
  10. Pell AC, Christie J, Keating JF, Sutherland GR. The detection of fat embolism by transoesophageal echocardiography during reamed intramedullary nailing. A study of 24 patients with femoral and tibial fractures. J Bone Joint Surg Br. 1993; 75(6):921-925.
  11. Husebye EE, Lyberg T, Madsen JE, Eriksen M, Roise O. The influence of a one-step reamer-irrigator-aspirator technique on the intramedullary pressure in the pig femur. Injury. 2006; 37(10):935-940.
  12. Joist A, Schult M, Ortmann C, et al. Rinsing-suction reamer attenuates intramedullary pressure increase and fat intravasation in a sheep model. J Trauma. 2004; 57(1):146-151.
  13. Goplen G, Astephen J, Kuniec S, Deluzio K, Leighton RK. A cadaver model of femoral intramedullary reaming pressures demonstrates reduced pressures with single pass irrigated reamer. In: Proceedings from the Annual Meeting of the Orthopaedic Trauma Association; 2003; Toronto, Canada. Abstract.
  14. Higgins TF, Casey V, Bachus K. Cortical heat generation using an irrigating/aspirating single-pass reaming vs conventional stepwise reaming. J Orthop Trauma. 2007; 21(3):192-197.

Authors

Mr Newman and Drs Stahel, Smith, Resende, Hak, and Morgan are from the Department of Orthopedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, Colorado.

Mr Newman and Drs Smith, and Resende have no relevant financial relationships to disclose. Drs Stahel, Hak, and Morgan have received lecturing fees and reimbursement for instructional courses that were co-sponsored by Synthes. Dr Morgan has received institutional research support from Sythnes.

Correspondence should be addressed to: Steven J. Morgan, MD, 777 Bannock St, Denver, CO 80204.

10.3928/01477447-20080301-29

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