| The minimization of morbidity in cranio-maxillofacial osseous reconstruction: Bone graft harvesting and coral-derived granules as a bone graft substitute | ||
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The iliac crest is a favoured extra-oral donor site because of its accessibility and the large quantity of bone available (Dingman 1950, Converse & Campbell 1954, Flint 1964, Levy & Siffert 1969, Crockford & Converse 1972, Mrazik et al. 1980, Hall & Smith 1981). Within the ilium, grafts may be harvested from either its anterior or posterior crest.
The anterior ilium provides an adequate volume of bone for many maxillofacial reconstructive procedures requiring grafting. A variety of techniques have been devised to reduce morbidity associated with harvesting bone from the anterior ilium (Wolfe & Kawamoto 1978, Mrazik et al. 1980, Grillon et al. 1984, Tilley & Davis 1984, van der Wal et al. 1986). The most commonly employed and least complex technique is to harvest a corticocancellous block through either a medial or lateral approach to the anterior ilium. No significant difference in morbidity has been found when comparing the medial and lateral approaches (Tayapongsak et al. 1994).
When a larger volume of bone is required, the posterior iliac crest should be considered (Bloomquist & Feldman 1980, Leyder et al. 1985). The posterior ilium provides a greater quantity of both cortical and cancellous bone with less morbidity than the lateral approach to the anterior ilium (Marx & Morales 1988). However, a major disadvantage of the posterior approach is the need to turn the patient intra-operatively from the prone to the supine position, thus leading to increased operating time plus the risk of injury to the patient during the change of operating position.
Utilizing the anterior ilium allows the graft harvest to be performed simultaneously with the preparation of the recipient site, thereby reducing operative and anaesthetic time. However, standard approaches to the ilium can still produce significant morbidity for the patient (Cocklin 1971, Marx & Morales 1988, Tayapongsak et al. 1994). Thus, there is an advantage to developing a method for obtaining bone from the anterior ilium, which is less invasive than the traditional method.
The most frequently cited complications of iliac bone harvesting are gait disturbance, post surgical pain, excessive blood loss, and paresthesia (Cocklin 1971, Marx & Morales 1988, Tayapongsak et al. 1994, de la Torre et al. 1999, Seiler & Johnson 2000). A 2% incidence of permanent sensory disturbance within the dermatomal distribution of the lateral femoral cutaneous nerve has been reported (van der Wal et al. 1986). Muscle dissection can contribute markedly to blood loss, disturbance of gait, and post surgical pain (Wolfe & Kawamoto 1978, Cowley & Anderson 1983, Laurie et al. 1984, Keller & Triplett 1987, Cohn & Krakow 1988, Arrington et al. 1996, Hill et al. 1999).
The current trend in most surgical specialties is the development of minimally invasive techniques, which are designed to minimize post-operative morbidity. Sophisticated instrumentation and miniaturized endoscopes have been developed to facilitate such surgery. These techniques include endoscopic cholecystectomy (Bradley & Dempsey 2002, Conlon & McMahon 2002), endoscopic face lifts and forehead lifts (Freeman 2001), endoscopic rhinoplasty (Tasca 2002), endoscopic sinus surgery (Venkatachelam & Jain 2002), temporomandibular joint arthroscopy (Liesenhoff & Funk 1994), and more recently endoscopic paediatric cardiac surgery (Tiete et al. 2002).
Traditionally, autogenous bone from the iliac crest has been harvested as corticocancellous blocks using an open approach, which requires significant dissection of soft tissues. Elevation of musculoperiosteal flaps to gain access to the iliac crest may result in significant post-operative morbidity, including pain, haematoma, delayed ambulation, and increased length of hospital stay. This is true whether an antero-medial, antero-lateral, or the posterior approach is used (Laurie et al. 1984, Marx & Morales 1988).
The philosophy of minimally invasive surgery can be extended to the procurement of autogenous bone by means of a trephine. Various techniques, which attempt to minimize morbidity have been reported (Dragoo & Irwin 1972, Schwartz & Leake 1979, Tilley & Davis 1984, Caddy & Reid 1985, Abubaker & Sotereanos 1989, Wagner & Moore 1991, McGurk et al. 1993, Altman & Blenkisopp 1994, Billmire & Rotatori 1994). In the past, trephines have been used to harvest bone biopsy specimens (Waldman & Kleinfeld 1970, Smirnov & Baranov 1971, Braun 1974, Schuyt et al. 1979, Johnson et al. 1997, Minns & Sher 1983). Initially, these trephines were small hand held instruments that were used with a twisting motion (Smirnov & Baranov 1971, Minn & Sher 1983, McGurk et al. 1993, Altman & Blenkisopp 1994) and later power driven ones were developed (Johnson et al. 1997, Faugere & Malluche 1983, Billmire & Rotatori 1994, Kreibich et al. 1994). While the safety and yield of trephines has been reported with respect to their use as a biopsy tool, their use in procuring bone grafts has not been thoroughly evaluated (Habal 1995).
The safety and benefit of trephines has been demonstrated by Kreibich who showed that the percutaneous sampling of bone when compared to open procedures resulted in significantly reduced pain, less pain on walking, less sensory disturbance and less local tenderness (Kreibich et al. 1994). Evaluation of the safety of biopsy trephines has shown a low incidence of complications (Duncan et al. 1980).
Trephines have a long history of application in bone biopsy harvesting for the diagnosis of metabolic bone diseases and for research purposes (Malluche & Faugere 1986). These biopsy techniques demand proper sampling without destruction of bone, thereby producing viable bone for grafting purposes.
Trephines are either hand powered or electrically driven drills. Previous studies (Smirnov & Baranov 1971, Faugere & Malluche 1983, Caddy & Reid 1985, McGurk et al. 1993, Altman & Blenkisopp 1994) have demonstrated the possibility of obtaining bone with hand powered trephines, although the samples were not quantified. The Craig Bone Biopsy Set® (George Tiemann, Hauppauge, New York, USA) has been studied for iliac crest harvesting for patients requiring a maxillary bone graft to reconstruct cleft palate defects (Caddy & Reid 1985). A small skin incision was made over the iliac crest and the cortex was breached only once as the angle of the trephine was changed for multiple passes. Quantification of the bone volume from one cadaver hip was estimated to be 4.15 cc of bone. No complications were reported with the 10 patients in the report (Caddy & Reid 1985).
McGurk reported on the use of a hand powered trephine that penetrated up to 8 cm in length. Although the diameter was not specified it was suggested that up to 6 cc of bone could be obtained. The results on 11 patients indicated no complications and reduced post-operative pain (McGurk et al. 1993). Care was suggested at depths greater than 80 mm.
The Zimmer Power Driven Trephine Drill® (Zimmer/Hall, Warsaw, Indiana, USA), which removes iliac bone of 7.5 mm in diameter has also been described as a harvesting technique (Johnson et al. 1997) This drill is used mostly for percutaneous bone biopsy of the iliac crest. In a 48 patient retrospective study morbidity was assessed in terms of post-operative pain, deep or superficial infection, and patient satisfaction. Based on these criteria, the reported morbidity rate was extremely low. Unfortunately there was no quantification of bone yield using this technique. This power driven trephine was aimed at right angles to the lateral surface of the ilium and although the reported complication rate is low, the medial cortex is always intentionally perforated in this technique, creating a potential risk of peritoneal disruption.
The Corb Needle Biopsy Set® (Zimmer/Hall, Warsaw, Indiana, USA), which obtains cores of up to 30 mm long with a variable diameter has also been evaluated (Billmire & Rotatori 1994). This set of instruments was described by these authors as being capable of harvesting 5 – 10 ml of cancellous bone from the anterior iliac crest. Morbidity was assessed as a function of donor site pain lasting greater than two weeks, post-operative dysesthesias, soft tissue haematoma or infection. This retrospective study of 20 donor cancellous bone graft sites reported that the morbidity rate was zero based on the above parameters (Billmire & Rotatori 1994). This report does not indicate the frequency or occurrence of perforations. Apparently, a resistance is felt before the needle punctures through the medial cortex ensuring minimal incidence of perforations. A comparison between a power driven trephine and the Jamshidi Needle® (Allegence Healthcare Corporation, Chicago, Illinois, USA) for the purposes of biopsy evaluation revealed no differences in qualitative aspects but significantly larger bone volumes were harvested with the power driven trephine (Faugere & Malluche 1983).
A number of researchers have evaluated the post-operative morbidity associated with the use of trephines (Duncan et al. 1980, Williams & Ford 1986, Billmire & Rotatori 1994). They have been shown to leave minimal scaring, decrease morbidity and produce less dysesthesia than open procedures (Billmire & Rotatori 1994). A retrospective study of complications following 14,810 iliac crest biopsies from 14 centres (Duncan et al. 1980) reported local haematomas, lateral cutaneous nerve neuropathies and pain in excess of 7 days duration, following 0.63% of trephinations. When the vertical approach was used the complication rate decreased to 0.36%. The use of the 8 mm diameter trephine drill had the highest rate of associated complications and only one major complication was reported being a fracture of the ilium in a patient with severe osteomalacia (Duncan et al. 1980). A case of a pneumoperitoneum has been reported and attributed to air entry into the pararenal space as a result of the direct penetration of the trephine; however, the trephine in this case was used at a 90° angle to the ilium (Williams & Ford 1986). A single case of avulsion of the anterior iliac spine in a post menopausal woman following a transiliac bone biopsy has been reported (Stellon et al. 1985). Several authors (Duncan et al. 1980, Faugere & Malluche 1983) believe that the likelihood of complications increase when heavy pressure is applied, rather than gently allowing the instrument to do its work. Compared to the complications published with respect to open iliac crest grafting (Wolfe & Kawamoto 1978, Cowley & Anderson 1983, Laurie et al. 1984, Keller & Triplett 1987, Cohn & Krakow 1988, Marx & Morales 1988, Tayapongsak et al. 1994, Arrington et al. 1996, Hill et al. 1999) the trephine technique seems both simple and attractive and may help to reduced donor site morbidity.