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Comparative anatomic study of anterior and posterior iliac crests as donor sites
J Oral Maxillofac 49:56%563.
Surg
1991
Comparative Anatomic Study of Anterior and Posterior Iliac Crests as Donor Sites MATTHEW B. HALL, DDS, MD,* WARREN P. VALLERAND, DDS,t DAVID THOMPSON, DMD,$ AND GREGORY HARTLEY, DMD§ Ten fixed human cadaver iliums from elderly persons were studied to compare the amounts of graft material present in the anterior and posterior ilium. Average intracortical volume of surgically accessible marrow space was 15.75 mL for the anterior and 39.24 mL for the posterior ilium. Comparison of marrow volume underlying equal surface areas revealed values of 8.4 mL for the anterior and 14.8 mL for the posterior ilium. The average total volume of compressed cancellous bone obtained was 12.87 mL for the anterior and 30.31 mL for the posterior ilium. The ratio of cortical bone window surface area to resultant immediately accessible graft material was 1:0.49 for the anterior and 1:0.75 for the posterior ilium. These results confirm the greater availability of cancellous bone in the posterior ilium.
muscles. The medial cortex of the posterior ilium forms part of the sacroiliac joint and this limits the procurement of cortical bone in the posterior ilium to the lateral aspect. Damage to the acetabular fossa or femoral head is a potential risk of the anterior approach. However, the fossa is not in immediate proximity to the region frequently harvested. Thus, it would appear that potential damage to the supporting skeletal joints is not as great a risk in the anterior approach. In choosing the donor site, factors such as type of reconstructive surgery, potential morbidity, and quantity of bone required must be considered. The quantity of bone required is often a major factor in choosing between anterior and posterior sites of the ilium, eg, when a large section of the mandible is to be reconstructed. Although multiple authors have addressed the various approaches with the emphasis on technique and morbidity, very little has been published in regard to potential amounts of donor material at various sites. In a study comparing the morbidity of the lateral anterior and posterior approaches to the ilium, Marx and Morales found the posterior approach to yield more bone than the lateral anterior approach.’ There are no other published studies dealing with the amount of potential graft material present in the anterior and posterior ilium. The purpose of this study was specifically to quantify and compare the amounts of graft material
The ilium is a common donor site for autogenous bone grafts for reconstructive surgery in the maxillofacial region. The anterior ilium is the most frequently chosen site. Numerous approaches to the anterior ilium exist. Frequently used techniques include trephination’; the lateral approach2-4; the superior approach5,6; the superior-lateral approach’; and the medial approach. 23738 The posterior ilium is another available site.‘,” The basic surgical plan and complexity are similar for the anterior and posterior approaches and morbidity is relatively minimal with both (Figs 1 and 2). Both involve potential risk of damage to adjacent structures such as sensory nerves and
* Chairman, Department of Hospital Dentistry, and Director, Section of Oral and Maxillofacial Surgery, University of Kentucky, Lexington, KY. t Assistant Professor, Department of Oral and Maxillofacial Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ. $ In private practice, Sarasota, FL; formerly, Resident, University of Florida, Jacksonville, FL. $ Private practice, Jacksonville, FL; formerly, Resident, University of Florida, Jacksonville, FL. Address correspondence and reprint requests to Dr Hall: Department of Oral and Maxillofacial Surgery, University of Kentucky College of Dentistry, Lexington, KY 40536-0084. 0 1991 geons
American
Association
of Oral
and Maxillofacial
Sur-
0278-2391/91/4908-0002$3.00/O
560
561
HALL ET AL
FIGURE I Schematic diagram of anterior iliac crest harvest, medial approach.
present in the anterior and posterior regions of the ilium and to determine such factors as the ratio of cortical surface to underlying cancellous bone and the effect of compression of graft material on total available volume. Materials and Methods Ten fixed human cadaver iliums (5 cadavers) were studied. All cadavers were of average height and weight and were from elderly persons, three of
FIGURE 3. crest.
Diagrammatic illustration of sectioning of the iliac
which were women. The ilium was removed from the cadaver and cleaned of all muscular and tendinous attachments. Each iliac crest was then divided into 11 sections from areas where grafts are typically obtained (1 to 4 representing anterior, 5 representing middle, 6 to 1I representing posterior) using an autopsy saw. To standardize comparisons,
VOLUME
OF MARROW
MEASURED
MARROW BONE)
FIGURE 2.
Schematic diagram of posterior iliac crest harvest.
SPACE
WITH WATER
(CANCELLOUS REMOVED
FIGURE 4. Diagram of measurement of marrow space volume and compressed cancellous bone volume.
562
ANTERIOR AND POSTERIOR ILIUM AS DONOR SITES
Table 2. Comparison of Values for Anterior and Posterior Iliac Crests l/2 AND
/
COMBINED VOLUME
CORTICAL REDUCED
CHRS
BONE
REMOVED
MIXED
COMPRESSED MEASURED
FIGURE 5. Diagram of measurement of combination ume of corticocancellous bone mixture.
of vol-
eight sections (4 anterior, and 4 posterior) had approximately the same dimension (2 x 5 cm) (Fig 3). The cancellous bone and marrow was then removed from each section, except the middle section in each specimen (section 5), because it contained no significant cancellous bone. Next, the volume of each cut section was measured using water. The compressed volume of the removed cancellous bone, alone and when mixed with either medial cortex cortical chips (anterior sections) or lateral cortex cortical chips (posterior sections), was then measured (Figs 4 and 5). Results The results are summarized in Table 1. Using these data, several comparisons and relationships were studied and significance of differences was analyzed using independent samples t tests (Table Table 1.
Anterior (mL)
TO CHIPS
Total volume Mean SD Volume under equal surface areas (20 cm’) Mean SD Total compressed marrow Mean SD Compressed marrow and cortical plate (ant. = 3 and 4, post. = 8 and 9) Mean SD Between sides differences Mean SD
Posterior (mL)
P
15.75 4.49
39.24 4.77
P<.oool
8.4 2.88
14.8 2.48
P<.oool
12.87 5.23
30.31 3.42
P<.ooo!
9.7 2.27
14.95 2.31
P<.oool
1.66 2.17
3.16 1.95
P < .28
2). The total volume averaged 50.38 + >.6 mL in men and 61.90 + 1.67 mL in women (P = .12). Discussion
The posterior aspect of the ilium contains appreciably more cancellous bone and marrow than the anterior ilium. Based on space volume measurements, the ratio comparing anterior:posterior is 1:2.5. Based on compressed marrow measurements, a ratio of 1:2.4 is obtained. This slight difference could be due to a lower cancellous bone density in the posterior ilium or the result of measurement error. Assuming reflection of equal-sized cortical bone windows (equivalent surface area), the amount of
Summary of Collected Data Specimen No. 1 (Female)
Anterior total volume (mL) Posterior total volume (mL) Sections 3 and 4 total volume (mL) Sections 8 and 9 total volume (mL) Anterior total compressed marrow (mL) Posterior total compressed marrow (mL) 3 and 4 marrow and cortex (mL) 8 and 9 marrow and cortex (mL)
Specimen No. 2 (Female)
Specimen No. 3 (Female)
Specimen No. 4 (Male)
Specimen No. 5 (Male)
R
L
R
L
R
L
R
L
R
L
13.8 41.0 6.4 15.8
19.2 44.2 10.6 17.4
8.4 38.9 5.1 15.3
10.1 36.5 4.3 14.6
13.2 35.0 6.8 11.0
13.4 28.6 6.2 9.8
19.4 41.6 11.4 15.4
20.0 44.2 11.2 17.0
19.8 40.6 10.8 15.6
20.2 41.8 11.2 16.2
10.8
14.4
5.4
6.6
9.4
9.0
18.5
18.6
17.4
18.6
27.8 8.5 17.6
34.0 10.2 17.2
27.1 8.2 17.2
25.2 6.8 11.1
28.2 7.8 11.8
27.6 7.2 13.0
33.4 11.5 15.0
33.6 13.0 16.4
32.4 11.6 14.8
33.8 12.2 15.4
563
HALL ET AL
The ratio of total marrow volume to total compressed cancellous bone is 1:0.79. This suggests that compressing the cancellous bone decreases its volume by 21%. Conclusions
FIGURE 6. Photograph showing difference in medial to lateral depth of marrow space between anterior (left) and posterior (right) sections of iliac crest.
immediately accessible graft material also greatly differs when comparing anterior and posterior sites. This is owing to the much greater medial-lateral depth of the posterior iliac marrow space. Figure 6 illustrates this difference. Based on marrow space volume, underlying equal cortical surface areas, an anterior:posterior ratio of 1: 1.76 is obtained. Based on actual total immediately accessible graft material (compressed marrow + one surface of cortical plate) a ratio of 1: 1.54 is obtained. When planning to reconstruct a defect of known volume, it would be helpful to have an estimate of the required size of the cortical bone window to be removed to obtain the needed volume. Based on these results the ratio of cortical bone window surface area (cm*) to resultant total immediately accessible graft material (cm31 for the anterior is 2.06: 1, and for the posterior is 1.34: 1. With these numbers as guide lines, for a 40-cm’ hemimandibular defect, if an anterior iliac approach is planned, reflection of an approximately 82.4-cm* cortical bone window can be anticipated. For the same defect, using a posterior approach, the approximate size of required cortical bone window is 53.6 cm*. These numbers should be considered as maximum size estimates due to the fact that they are based on obtaining graft material only immediately underlying the cortical bone window. It is common practice to use an orthopedic curette to obtain marrow from the marrow cavity adjacent to the cortical bone window as well as immediately underlying it.
Based on this study, as a donor site, the posterior ilium provides significantly more graft material than the anterior. This holds true even when correcting for differences in surface area. These results are in general agreement with Marx and Morales who found the posterior approach to the ilium to yield more graft material than the lateral anterior approach.” Fixed cadaver cancellous bone may differ from fresh vital cancellous bone in its handling characteristics and compressibility, and it is difficult to standardize compression of the specimens. Also, the donor sites in younger adults may contain more cancellous bone than those in older persons. Given these limitations, it is not possible to directly apply these ratios as exact predictors of graft volume requirements in the surgical setting. However, we do feel that these can serve as accurate estimating guidelines and can be helpful in decision making and treatment planning when the need for an iliac graft is anticipated. References 1. Scott W, Peterson RC, Grant S: A method of procuring iliac bone by trephine curettage. .I Bone Joint Surg 3lA:860, 1949 2. Mrazik J, Amato C, Leban S, et al: The ilium as a source of autogenous bone for grafting: Clinical considerations. J Oral Surg 38:29, 1980 3. Farhood V. Doran E, Johnson R: A modified approach to the ilium to obtain graft material. J Oral Surg 36:784, 1978 4. Crockford D, Converse JM: The ilium as a source of bone grafts in children. Plast Reconstr Surg 50:270, 1972 5. Crenshaw AH (ed): Campbell’s Operative Orthopedics (ed 5). St Louis, MO, Mosby, 1971. pp 51-54. 6. Kazanjian VH, Converse JM: Surgical Treatment of Facial Injuries (ed 31. Baltimore, MD, Williams & Wilkins, 1974. pp 572-578 7. Levy R. Siffert R: Inner table iliac bone graft. Surg Gynecol Obstet 128605. 1969 8. Hall MB, Smith RG: The medial approach for obtaining iliac bone. J Oral Surg 39:462. 1981 9. Marx RE, Morales MJ: Morbidity from bone harvest in major jaw reconstruction: A randomized trial comparing the lateral anterior and posterior approaches to the ilium. J Oral Maxillofac Surg 48:1%, 1988 10. Bell WH. Proffrt WR, White RP Jr: Surgical Correction of Dentofacial Deformities, vol 2. Philadelphia, PA, Saunders. 1980. pp 1504-1517
Surg
1991
Comparative Anatomic Study of Anterior and Posterior Iliac Crests as Donor Sites MATTHEW B. HALL, DDS, MD,* WARREN P. VALLERAND, DDS,t DAVID THOMPSON, DMD,$ AND GREGORY HARTLEY, DMD§ Ten fixed human cadaver iliums from elderly persons were studied to compare the amounts of graft material present in the anterior and posterior ilium. Average intracortical volume of surgically accessible marrow space was 15.75 mL for the anterior and 39.24 mL for the posterior ilium. Comparison of marrow volume underlying equal surface areas revealed values of 8.4 mL for the anterior and 14.8 mL for the posterior ilium. The average total volume of compressed cancellous bone obtained was 12.87 mL for the anterior and 30.31 mL for the posterior ilium. The ratio of cortical bone window surface area to resultant immediately accessible graft material was 1:0.49 for the anterior and 1:0.75 for the posterior ilium. These results confirm the greater availability of cancellous bone in the posterior ilium.
muscles. The medial cortex of the posterior ilium forms part of the sacroiliac joint and this limits the procurement of cortical bone in the posterior ilium to the lateral aspect. Damage to the acetabular fossa or femoral head is a potential risk of the anterior approach. However, the fossa is not in immediate proximity to the region frequently harvested. Thus, it would appear that potential damage to the supporting skeletal joints is not as great a risk in the anterior approach. In choosing the donor site, factors such as type of reconstructive surgery, potential morbidity, and quantity of bone required must be considered. The quantity of bone required is often a major factor in choosing between anterior and posterior sites of the ilium, eg, when a large section of the mandible is to be reconstructed. Although multiple authors have addressed the various approaches with the emphasis on technique and morbidity, very little has been published in regard to potential amounts of donor material at various sites. In a study comparing the morbidity of the lateral anterior and posterior approaches to the ilium, Marx and Morales found the posterior approach to yield more bone than the lateral anterior approach.’ There are no other published studies dealing with the amount of potential graft material present in the anterior and posterior ilium. The purpose of this study was specifically to quantify and compare the amounts of graft material
The ilium is a common donor site for autogenous bone grafts for reconstructive surgery in the maxillofacial region. The anterior ilium is the most frequently chosen site. Numerous approaches to the anterior ilium exist. Frequently used techniques include trephination’; the lateral approach2-4; the superior approach5,6; the superior-lateral approach’; and the medial approach. 23738 The posterior ilium is another available site.‘,” The basic surgical plan and complexity are similar for the anterior and posterior approaches and morbidity is relatively minimal with both (Figs 1 and 2). Both involve potential risk of damage to adjacent structures such as sensory nerves and
* Chairman, Department of Hospital Dentistry, and Director, Section of Oral and Maxillofacial Surgery, University of Kentucky, Lexington, KY. t Assistant Professor, Department of Oral and Maxillofacial Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ. $ In private practice, Sarasota, FL; formerly, Resident, University of Florida, Jacksonville, FL. $ Private practice, Jacksonville, FL; formerly, Resident, University of Florida, Jacksonville, FL. Address correspondence and reprint requests to Dr Hall: Department of Oral and Maxillofacial Surgery, University of Kentucky College of Dentistry, Lexington, KY 40536-0084. 0 1991 geons
American
Association
of Oral
and Maxillofacial
Sur-
0278-2391/91/4908-0002$3.00/O
560
561
HALL ET AL
FIGURE I Schematic diagram of anterior iliac crest harvest, medial approach.
present in the anterior and posterior regions of the ilium and to determine such factors as the ratio of cortical surface to underlying cancellous bone and the effect of compression of graft material on total available volume. Materials and Methods Ten fixed human cadaver iliums (5 cadavers) were studied. All cadavers were of average height and weight and were from elderly persons, three of
FIGURE 3. crest.
Diagrammatic illustration of sectioning of the iliac
which were women. The ilium was removed from the cadaver and cleaned of all muscular and tendinous attachments. Each iliac crest was then divided into 11 sections from areas where grafts are typically obtained (1 to 4 representing anterior, 5 representing middle, 6 to 1I representing posterior) using an autopsy saw. To standardize comparisons,
VOLUME
OF MARROW
MEASURED
MARROW BONE)
FIGURE 2.
Schematic diagram of posterior iliac crest harvest.
SPACE
WITH WATER
(CANCELLOUS REMOVED
FIGURE 4. Diagram of measurement of marrow space volume and compressed cancellous bone volume.
562
ANTERIOR AND POSTERIOR ILIUM AS DONOR SITES
Table 2. Comparison of Values for Anterior and Posterior Iliac Crests l/2 AND
/
COMBINED VOLUME
CORTICAL REDUCED
CHRS
BONE
REMOVED
MIXED
COMPRESSED MEASURED
FIGURE 5. Diagram of measurement of combination ume of corticocancellous bone mixture.
of vol-
eight sections (4 anterior, and 4 posterior) had approximately the same dimension (2 x 5 cm) (Fig 3). The cancellous bone and marrow was then removed from each section, except the middle section in each specimen (section 5), because it contained no significant cancellous bone. Next, the volume of each cut section was measured using water. The compressed volume of the removed cancellous bone, alone and when mixed with either medial cortex cortical chips (anterior sections) or lateral cortex cortical chips (posterior sections), was then measured (Figs 4 and 5). Results The results are summarized in Table 1. Using these data, several comparisons and relationships were studied and significance of differences was analyzed using independent samples t tests (Table Table 1.
Anterior (mL)
TO CHIPS
Total volume Mean SD Volume under equal surface areas (20 cm’) Mean SD Total compressed marrow Mean SD Compressed marrow and cortical plate (ant. = 3 and 4, post. = 8 and 9) Mean SD Between sides differences Mean SD
Posterior (mL)
P
15.75 4.49
39.24 4.77
P<.oool
8.4 2.88
14.8 2.48
P<.oool
12.87 5.23
30.31 3.42
P<.ooo!
9.7 2.27
14.95 2.31
P<.oool
1.66 2.17
3.16 1.95
P < .28
2). The total volume averaged 50.38 + >.6 mL in men and 61.90 + 1.67 mL in women (P = .12). Discussion
The posterior aspect of the ilium contains appreciably more cancellous bone and marrow than the anterior ilium. Based on space volume measurements, the ratio comparing anterior:posterior is 1:2.5. Based on compressed marrow measurements, a ratio of 1:2.4 is obtained. This slight difference could be due to a lower cancellous bone density in the posterior ilium or the result of measurement error. Assuming reflection of equal-sized cortical bone windows (equivalent surface area), the amount of
Summary of Collected Data Specimen No. 1 (Female)
Anterior total volume (mL) Posterior total volume (mL) Sections 3 and 4 total volume (mL) Sections 8 and 9 total volume (mL) Anterior total compressed marrow (mL) Posterior total compressed marrow (mL) 3 and 4 marrow and cortex (mL) 8 and 9 marrow and cortex (mL)
Specimen No. 2 (Female)
Specimen No. 3 (Female)
Specimen No. 4 (Male)
Specimen No. 5 (Male)
R
L
R
L
R
L
R
L
R
L
13.8 41.0 6.4 15.8
19.2 44.2 10.6 17.4
8.4 38.9 5.1 15.3
10.1 36.5 4.3 14.6
13.2 35.0 6.8 11.0
13.4 28.6 6.2 9.8
19.4 41.6 11.4 15.4
20.0 44.2 11.2 17.0
19.8 40.6 10.8 15.6
20.2 41.8 11.2 16.2
10.8
14.4
5.4
6.6
9.4
9.0
18.5
18.6
17.4
18.6
27.8 8.5 17.6
34.0 10.2 17.2
27.1 8.2 17.2
25.2 6.8 11.1
28.2 7.8 11.8
27.6 7.2 13.0
33.4 11.5 15.0
33.6 13.0 16.4
32.4 11.6 14.8
33.8 12.2 15.4
563
HALL ET AL
The ratio of total marrow volume to total compressed cancellous bone is 1:0.79. This suggests that compressing the cancellous bone decreases its volume by 21%. Conclusions
FIGURE 6. Photograph showing difference in medial to lateral depth of marrow space between anterior (left) and posterior (right) sections of iliac crest.
immediately accessible graft material also greatly differs when comparing anterior and posterior sites. This is owing to the much greater medial-lateral depth of the posterior iliac marrow space. Figure 6 illustrates this difference. Based on marrow space volume, underlying equal cortical surface areas, an anterior:posterior ratio of 1: 1.76 is obtained. Based on actual total immediately accessible graft material (compressed marrow + one surface of cortical plate) a ratio of 1: 1.54 is obtained. When planning to reconstruct a defect of known volume, it would be helpful to have an estimate of the required size of the cortical bone window to be removed to obtain the needed volume. Based on these results the ratio of cortical bone window surface area (cm*) to resultant total immediately accessible graft material (cm31 for the anterior is 2.06: 1, and for the posterior is 1.34: 1. With these numbers as guide lines, for a 40-cm’ hemimandibular defect, if an anterior iliac approach is planned, reflection of an approximately 82.4-cm* cortical bone window can be anticipated. For the same defect, using a posterior approach, the approximate size of required cortical bone window is 53.6 cm*. These numbers should be considered as maximum size estimates due to the fact that they are based on obtaining graft material only immediately underlying the cortical bone window. It is common practice to use an orthopedic curette to obtain marrow from the marrow cavity adjacent to the cortical bone window as well as immediately underlying it.
Based on this study, as a donor site, the posterior ilium provides significantly more graft material than the anterior. This holds true even when correcting for differences in surface area. These results are in general agreement with Marx and Morales who found the posterior approach to the ilium to yield more graft material than the lateral anterior approach.” Fixed cadaver cancellous bone may differ from fresh vital cancellous bone in its handling characteristics and compressibility, and it is difficult to standardize compression of the specimens. Also, the donor sites in younger adults may contain more cancellous bone than those in older persons. Given these limitations, it is not possible to directly apply these ratios as exact predictors of graft volume requirements in the surgical setting. However, we do feel that these can serve as accurate estimating guidelines and can be helpful in decision making and treatment planning when the need for an iliac graft is anticipated. References 1. Scott W, Peterson RC, Grant S: A method of procuring iliac bone by trephine curettage. .I Bone Joint Surg 3lA:860, 1949 2. Mrazik J, Amato C, Leban S, et al: The ilium as a source of autogenous bone for grafting: Clinical considerations. J Oral Surg 38:29, 1980 3. Farhood V. Doran E, Johnson R: A modified approach to the ilium to obtain graft material. J Oral Surg 36:784, 1978 4. Crockford D, Converse JM: The ilium as a source of bone grafts in children. Plast Reconstr Surg 50:270, 1972 5. Crenshaw AH (ed): Campbell’s Operative Orthopedics (ed 5). St Louis, MO, Mosby, 1971. pp 51-54. 6. Kazanjian VH, Converse JM: Surgical Treatment of Facial Injuries (ed 31. Baltimore, MD, Williams & Wilkins, 1974. pp 572-578 7. Levy R. Siffert R: Inner table iliac bone graft. Surg Gynecol Obstet 128605. 1969 8. Hall MB, Smith RG: The medial approach for obtaining iliac bone. J Oral Surg 39:462. 1981 9. Marx RE, Morales MJ: Morbidity from bone harvest in major jaw reconstruction: A randomized trial comparing the lateral anterior and posterior approaches to the ilium. J Oral Maxillofac Surg 48:1%, 1988 10. Bell WH. Proffrt WR, White RP Jr: Surgical Correction of Dentofacial Deformities, vol 2. Philadelphia, PA, Saunders. 1980. pp 1504-1517