European Journal of Cardiovascular Medicine

Bone grafts have been used since the seventeenth century for a variety of orthopaedic complications including non-union of long bones, biological failure of healing, bone loss following trauma, osteonecrosis,tumour resection, osteomyelitis, etc. (1, 2).Although reconstruction of soft-tissue defects requires a fasciocutaneous or musculocutaneous flap, composite tissue loss that includes bone should be managed with a flap that contains vascularized bone (4).. Commonly used bone for grafting is fibula, iliac crest, rib, etc. Among them all, fibular graft is the most viable option for the treatment of skeletal defects (6).

Fibula has the highest tensile strength when compared to other bones (12).The length, structure and predictable vascular pedicle of fibula make it an ideal cortical bone graft. Clinically useful cartilaginous grafts are obtained from fibula (14).  Harvesting upper part of fibula without disturbing the tibiofibular mortise produces very less complications (15).

For the graft to be successful, harvesting should include the blood supply of the fibula. Detailed anatomical knowledge of arterial supply of fibula is necessary to raise the osteofasciocutaneous free flaps of fibula. The main source of the blood supply to the fibula is from nutrient artery, which is the branch of the peroneal (fibular) artery. The best anatomical region for a vascularized fibular transfer is at an average of 20% up to 75% of the fibular length (18).

Fibula does not follow the law of ossification (7). For shorter grafts one must consider the number and location of nutrient foramens (20).Nutrient artery of fibula is the main blood supply to fibula in addition to the periosteal arteries. Nutrient artery to fibula and most of the periosteal arteries to fibula arise from peroneal artery that can be harvested along with bone segment. Nutrient artery enters fibula at a specific site. Hence it was decided to study the number, direction, location and position nutrient artery of fibula and then to correlate it with free fibular graft harvesting.

The study was a cross sectional, observational study. Study was conducted on adult dry human fibula from the Department of Anatomy, government medical college, Srikakulam.Total of 120 dry bones were numbered and 102 random numbers were generated using EPI6. And these 102 bones were selected from 120 by random sampling technique.

Fibula was examined for the nutrient foramina and number of nutrient foramina on the shaft of fibula with the help of a hand lens and recorded. Nutrient foramen was marked by a groove leading into it on the shaft of fibula and slightly raised edge of the nutrient canal at its origin. Direction of nutrient foramen was confirmed by inserting a small needle in to the canal of the nutrient foramen. The location of nutrient foramen in relation to surfaces and borders of fibula were observed. At the same time, diameter of the nutrient foramen was approximately measured by gently inserting the needles of different caliber in increasing order.Theposition of nutrient foramen was identified by calculating foraminal index (FI) using the formula, FI = DNF / TL X 100.DNF is the( distance of nutrient foramen from styloid process), TL is the t(otal length of fibula).

After calculating the foraminal index, the position of nutrient foramen was determined from the range of foraminal index as follows

33. <33.34 à                          nutrient
34. foramen in upper third
35. 34 – 66.67 à nutrient foramen in middle third
36. > 66.67 à nutrient foramen in lower third

102 dry adult human fibulae have been studied and side, number, direction, DNF, total length, position, locationof the nutrient foramen, and diameters of fibula at the level of nutrient foramen were observed.The observations  are as follows .Out of 102 bones examined, all the bones showed nutrient foramina. 93 bones showed single nutrient foramen, 9 bones showed double nutrient foramina and none of the bones showed nutrient foramina more than 2. Among the fibulae having double nutrient foramina, two were left sided bones and remaining 7 were right sided. In the Left sided fibulae, 96% of the bones having single nutrient foramina when compared to that of right side (88%).Out of the 111 nutrient foramina examined in 102 bones, 102 foramina were directed towards the inferior end of the bone and the rest 9 nutrient foramina were directed towards the superior end i.e., growing end. The average distance of nutrient foramen from the tip of styloid process was 15.82 ± 3.45 cm. The average length of nutrient foramen from the tip of styloid process in right-sided fibulae was 15.89 ± 3.45 and in left sided fibulae was 15.73 ± 3.31 .The mean length of the fibulae was 34.93  ± 2.63 cm. The average length of right-sided fibula was 34.99 ± 2.62 cm and that of left side was 34.83 ± 2.64 cm . Position of nutrient foramina on fibulae was determined by calculating the foraminal index using the formula DNF/Total Length X 100 where DNF stands for distance of nutrient foramen from proximal end of the fibulae.91 % of nutrient foramina were present in the middle third of the fibulae. In the bones showing double foramina, 77.78 % of nutrient foramina were present in middle third of fibulae.The mean foraminal index was 45.23 ± 8.81. The range of foraminal index was from 27.89 to 70.67. The average of foraminal index of nutrient foramina in upper third was 31.23 ± 2.21. The average of foraminal index of nutrient foramina in middle third was 45.06 ± 8.63. The average of foraminal index of nutrient foramina in lower third was 68.67 ± 1.8. The p value for foraminal index was 0.709 that is insignificant.The standard deviation of foraminal index for the fibula having nutrient foramina in the middle third is highest when compared to other two parts.Around 40% of the nutrient foramina were present in the posterior surface of fibulae followed by almost equal contribution 39% were in the postero-medial border.

Observations in the cadaveric dissection

The mean length of fibula was found to be 34.44 ± 2.19 cm and average distance of nutrient foramen from the upper end of fibula was 16.21 ± 3.5 cm. All the bones show only one nutrient foramen and the direction of nutrient artery were downward. No anomalous nutrient artery was found. The mean foraminal index was 47.16 ± 10.1.

Many authors had studied fibula for side, number, direction, position and location of nutrient foramen, total length of fibula and diameter of shaft of fibula at the level of nutrient foramen. Comparisons of previous studies of fibula found in the literature with our study as follows.

Table. 1 Showing comparison of number of NF with previous studies

Table 2. Showing comparison of FI with previous studies

Table 3. Showing comparison of location of NF with previous studies

The number of NF, direction, position, location and foraminal index of fibulae were studied after taking account to the previous studies and results were correlated with the previous studies. The results were coinciding with most of the studies. It can be inferred that nutrient artery is present in the middle third of the fibula. Our findings correlate with most of the previous studies. To be more precise, it can be taken as present just above the midpoint of fibula. Fibula of length as long as 26 cm can be harvested with very less complications. In addition to this, fibula can be harvested along with soft tissue structures make it almost ideal graft. So middle third of fibula should be used for fibular grafting.

There has been no previous study on cadaveric dissection to correlate the findings of our study.Hence, we could not compare our findings. Observations of our cadaveric study coincides with the findings of our dry bone study.Cadaveric dissections confirm that nutrient artery enters the fibula at the middle third of fibula.

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