Efficacy of Treating Chronic Tibial Osteomyelitis With Bone Defect Using a Pedicled Perforator-Layered Flap and Fasciocutaneous Flap of the Posterior Tibial Artery: A Case Report

Often caused by ineffective or untimely treatment of acute osteomyelitis, chronic osteomyelitis of the tibia is an infection of the bone and bone marrow.¹ Tibial osteomyelitis frequently creates sizable tissue defects.¹ Osteomyelitis is a difficult problem in surgery as it is more likely to result in complications such as chronic sinus tract, scarring at the surgical site, and bone defect. Furthermore, osteomyelitis may cause a high rate of operation failure and recurrence of infection.^2,3 Therefore, simultaneously achieving good soft tissue coverage and long-term prevention against local infection is key to the treatment of bone defect and bone exposure caused by chronic osteomyelitis of the tibia.¹ Current surgical approaches for tibial osteomyelitis include antibiotic bone cement filling, bone resection, and fenestration operations and lavage muscle flap filling.¹

The fasciocutaneous flap is a tissue flap consisting of skin, subcutaneous tissue, and underlying fascia. To the authors’ knowledge, to date there is no precise definition of a layered tissue flap nor has a consensus been reached. There are reports in the literature regarding the use of a layered tissue flap to repair wounds. Chen et al⁴ used an abdominal double-layer subcutaneous tissue flap to repair a complex hand injury. The abdominal flat flap was separated in the superficial fascia level to form the double-layer tissue flap, which contained shallow and deep layers; the deep layer tissue flap was placed upon the tendon and metacarpal bone, and the shallow layer tissue flap was used to cover and seal the soft tissue defect.⁴ Liu et al⁵ used the double-layer tissue flap. The descending branch of the lateral femoral circumflex artery was designed as the pedicle, the dominating femoral muscle branch formed the muscular flap, and the musculocutaneous branch formed the subcutaneous flap. The muscular flap was placed in the marrow cavity and the subcutaneous flap covered and sealed the soft tissue defect. The double-layer tissue flap is clinically used to treat limb osteomyelitis accompanied with soft tissue defect, facial tumor resection, and repair.^5–7

These operations use different branches from the same main artery to nourish different levels of tissue; the tissue flap is later split into 2 layers, forming a double-layered tissue flap.^4–7 The tissue flap, either an axial tissue flap with a vascular pedicle or a free tissue flap, is used to repair different stages of tissue defect. The design of the layered tissue flap provides an alternative method for repairing hard-to-heal wounds.^4–7 A non-microsurgical operation considered to be relatively simple and safe in treating chronic osteomyelitis of the tibia is the pedicled layered fasciocutaneous flap. In the present case report, the authors selected the pedicled layered fasciocutaneous flap.

The patient was a 54-year-old male who developed an ulcer on the anterior tibia of the left lower limb 40 years ago due to trauma. After initial treatment, a scar formed (approximately 8 cm x 3 cm). The scar repeatedly ruptured, discharged pus, and was accompanied by the formation of a soft tissue sinus tract, indicating potential necrosis or infection. After 12 years of treatment following the initial trauma, the sinus tract healed and did not relapse. The patient exhibited ulceration and purulent discharge at the left anterior tibial scar location as well as a fever

(39 °C) 28 years after completing treatment. The patient was treated at a small clinic at first and later at the authors' hospital, where the patient was hospitalized and treated by the Department of Burns staff. One week after presenting to the authors' hospital, debridement of the left anterior tibial sinus tract with negative pressure wound therapy ([NPWT] VSD; Wuhan VSD Medical Science and Technology Co. Ltd)⁸ and anti-infective treatment were performed. On day 14 post admission, the negative pressure drainage material was removed, and the wound dressing was changed. An x-ray and magnetic resonance imaging (MRI) were ordered, and examination of the results indicated left tibial osteomyelitis. When the patient was admitted to the hospital, the wound, located in the anterior and middle parts of the left tibia, included exposure of the tibial bone (approximately 1 cm x 5 cm). The exposed bone was yellow. The peripheral edge of the wound was covered with old scar tissue, a small amount of necrotic tissue residue was on the surface of the wound, and small amounts of secretion were attached. The MRI examination was done (Figure 1).

In order to prepare the wound bed for the flap procedure, anti-infection treatments combined with surgical debridements and NPWT were carried out on day 4 post admission (Figure 2). The wound dressing was changed daily for 3 days before surgical debridement. From the infected soft tissue, a wound bacterial culture and drug sensitivity test were conducted on day 1 post admission, and the results came back on day 3 post admission; Escherichia coli was detected. Based on the drug sensitivity results, the patient was given cefamandole nafate sterile. The patient was treated with broad-spectrum antibiotics for 2 weeks.

On the day of each debridement (ie, days 4, 8, 13, and 17 post admission), both a bacteria culture and drug sensitivity test were to be done before treatment or when the negative pressure device was removed. Bacterial culture results taken on days 4 and 8 (ie, 2 days after each sampling, the results would be released on days 6 and 10) showed an Enterococcus faecium infection of the tibia cavity. Based on the drug sensitivity results, vancomycin was used for anti-infective treatment.

The combination of debridement and NPWT was performed 3 times (on days 4, 8, and 13) during the course of hospitalization (Figure 3). The granulation tissue formed slowly in the wound and bacterial culture examination was positive during the time. The device was set to continuous pressure of 75 mm Hg. The results of the bacterial culture examination after the third debridement and application of NPWT were negative.

On day 17, the fourth debridement, without subsequent NPWT, was performed. The left bone marrow cavity volume was roughly 2 cm x 6 cm x 3 cm. The design of the pedicled layered fasciocutaneous flap with the cutaneous branch of posterior tibial artery was as follows: first, doppler ultrasound was used to detect the perforating sites of cutaneous branches of the posterior tibial artery; second, the pedicled posterior tibial artery perforator flap was excised (8 cm x 10 cm), and the pedicle width was about 5 cm; and third, starting at the distal end of the primary flap, the flap was dissected by surgical blade and surgical scissors from the fat level (about 2 mm under the superficial fascia), and the sharp separation was about 4 cm lengthwise. The primary flap was then divided into the skin flap and adipofascial flap, creating a double-layer flap. The skin flap contained the epidermis, dermis, superficial fascia, and shallow fat layer, which was about 2 mm below the superficial fascia; the skin flap was about 1 cm thick, 8 cm in length, and 10 cm in width. The adipofascial flap included the deep fat layer, which about 2 mm fall below the superficial fascia and deep fascia; the adipofascial flap was about 1 cm thick, 4 cm in length, and 10 cm in width. The adipofascial flap was gently curled in a vertical fashion and filled the bone marrow cavity (2 cm x 3 cm x 6 cm, corresponding to the dimensions of the adipofascial flap ). Subsequently, the skin flap was shifted to the lateral edge of the wound to cover and seal all the exposed wounds (Figure 4). The large split-thickness skin grafts were transplanted to repair the donor area wound. Bacterial culture results taken on day 17 (ie, results were obtained on day 19 post admission) were negative. Sterile gauze was used to cover the site, and sensitive antibiotics were used post operation (ie, vancomycin was used until day 20 post admission).

Through prophylactic infection treatment combined with 3 debridements with NPWT, good wound bed preparation was obtained (ie, after a period of antibacterial therapy, the bacterial culture changed from positive to negative and the upper and lower ends of the marrow cavity were filled with fresh granulation tissue). After the fourth debridement, the pedicled posterior tibial artery fasciocutaneous flap was used to fill the defect of bone marrow cavity and cover both the exposed tibia and tissue defect. The dressing of the wound was changed every day from day 1 to day 7 post operation, and the dressing of the wound was changed interval days from day 8 post operation until the day discharge. In addition, the affected limb was elevated and oral drugs promoting venous return were used. A total of 14 days post operation, the patient was discharged. At the 6-month follow-up, there were no signs of recurrence at the wound repair site, no osteomyelitis in the tibia, and no local venous reflux disturbance in the leg (Figure 5).

Chronic osteomyelitis refers to the inflammation of bone tissue typically caused by microbial infection. Most chronic osteomyelitis occurs as a result of ineffective or untimely treatment of acute osteomyelitis. The treatment of chronic osteomyelitis requires initial and timely use of antibiotics. Multiple specimens should be taken from the wound site for bacterial culture and drug sensitivity test.^1,2 According to the results of the present drug sensitivity test, the authors adjusted the use of antibiotic sensitivity.

In the present case, thorough debridement and application of NPWT were carried out while anti-infective treatment was based on drug sensitivity. Thorough debridement is the basis for prevention and treatment of infection.¹ The sinus tract, necrotic bone, foreign body, and scar tissue should be thoroughly removed, and the granulation tissue in the dead cavity should be scraped off.¹ Until relatively healthy and blood-rich tissue wounds appear, the necrotic bone and the edge of the cavity should be removed.¹ After debridement, NPWT could be used to fill the marrow cavity and maintain drainage.^5,9,10  If debridement with NPWT does not yield positive results, serial debridements are necessary until the bone marrow cavity is filled with fresh granulation tissue.

After debridement, eliminating dead space and repairing soft tissue defect are key to promote healing. When repairing a soft tissue defect resulting from chronic osteomyelitis, the first line of treatment that should be considered is a local muscle flap, because the local muscle flap has a more abundant blood supply than a skin flap and therefore can better meet the treatment needs of chronic osteomyelitis.¹

There may be no differences between muscle and perforator fasciocutaneous flaps used for reconstruction in osteomyelitis after wide debridement.^2,3

However, removal of the local muscle flap will also damage the original physiological function of the muscle group of lower leg.^11,12 Free tissue flap transplantation can overcome this dilemma, and it has great advantages in eliminating dead space and repairing soft tissue defect after debridement of chronic osteomyelitis; however, it still has an overall failure rate of 3.9%.¹³ The preparation of the wound bed for flap transplantation is vital, especially in relation to a certain vascular anastomosis technique; as a result, the wide application of free flap is limited.^12,14–16

The design was effective in simplifying the treatment approach in the present case. The author’s team considered how to repair tibial osteomyelitis with a bone defect in a non-microsurgical manner while trying to avoid damage to the original function of leg muscles,^11,12 which resulted in the decision to use a pedicled layered fasciocutaneous flap.

The posterior tibial artery perforator flap is the most widely used flap in the repair of leg wounds.^11,16,17 The perforator branches of the posterior tibial artery in the muscular space of the leg are relatively constant.¹⁸

The cutaneous branches of the posterior tibial artery at the distal end of the leg enter the subdermis immediately after passing through the deep fascia and form a subdermal vascular network. Previous literature has found that the blood supply of the upper and horizontal cutaneous branches had no obvious decrease when the deep fat and/or deep fascia under the flap were stripped off.^18,19

The skin flap is rich in subdermal vascular network consisting of ascending and horizontal branch of the posterior tibial artery perforator. Because the blood supply of deep fascia and deep fat is independent of the blood supply of superficial fascia, after carefully and acutely separating the skin flap from the fat level, which about 2 mm under the superficial fascia, the adipofascial flap still has the blood supply from preserving subfascial plexu.^18–20 It should be noted that the design of the adipofascia flap, because of its dual arterial supply (perforator and random) and dual venous drainage, lowers the probability of venous congestion and arterial spasm compared with the island flap.¹⁴ The primary flap, divided into a double-layer flap, repairs multiple anatomical levels of soft tissue defect.

The design of the present double-layered fasciocutaneous flap has several potential advantages. Since the pedicled tissue flap transfer is easy to cut, there is no need to carry out vascular anastomosis and the operation is relatively simple. The operation is performed on the same limb with shallow anatomy. Without sacrificing the main arteries of the limbs, the blood supply to the injured limb is less damaged, and the adverse factors of wound healing do not increase.¹⁷ The operation of the posterior tibial artery perforator flap does not affect the original physiological function of lower limb muscles.¹¹ The adjacent tissues of the same limb are similar in structure.¹⁴ Upon achieving good wound bed preparation, a single flap operation was performed to repair the bone marrow cavity, bone exposure, and soft tissue defects simultaneously. The effective blood supply of a layered fasciocutaneous flap was used to achieve the goal of anti-infection in the long-term phase of bone marrow cavity. This conclusion is based on the present case and the literature.¹ The myocutaneous flap was used to enhance regional blood supply of marrow cavity. In the present case, the adipofascial flap was used to fill the bone marrow cavity to achieve the purpose of providing stable blood supply.

Based on the present case report, the authors propose potential indications for this type of layered tissue flap. The wound surface is not at the same anatomical level, such as soft tissue and bone defect or soft tissue and subtendon tissue defect, in both acute and chronic complex wounds; in the present case, chronic osteomyelitis of the tibia caused a small area of bone defect with bone exposure, where no bone grafting was needed. The authors believe that attention should be paid to the following items in treatment: (1) debridement should be thorough; (2) the site should be relatively clean and the wound culture negative; (3) the adipofascia flap, which carries part of the sarcolemma at the distal end to prevent the deep fascia from being avulsed during operation, requires that the design of the pedicle should be relatively wide and the rotation angle should be less than 90 degrees; (4) hemostasis should be thorough in the donor site; (5) tension of both layers of the tissue flap should be appropriate (ie, the size of the tissue flap needs to be designed reasonably; if the size is too small, greater tension will be formed during suture and affect blood supply, and if the size is too large, it will become bloated and need unnecessary cutting); (6) the adipofascio flap should be gently curled along the length of the flap to fill the marrow cavity, leaving no dead space; and (7) the drainage tube should be placed under the flap, and the nature and quantity of drainage fluid should be observed.

The use of a layered fasciocutaneous flap to repair soft tissue defects provided a relatively simple, safe, and effective method for the repair of a small area of bone defect with bone exposure resulting from chronic tibial osteomyelitis. It is noteworthy that although the perforator flap can provide an optimized method for wound repair, it is also necessary to use the vascular anastomosis technique in conjunction if necessary.

While similar double-layer tissue flaps have been used to repair wounds with varying anatomical levels of tissue defects, especially associated with the bone marrow cavity, future reports should observe the long-term follow-up results in cases of chronic osteomyelitis of the tibia.

Authors: Zhengguo Xia, MD¹; Chunhua Wang, MD²; Ashley Arnold, MB²; Junhui Song, MSM²; Yizhong Tang, MSM²; Qinglian Xu, MD²; and Linsen Fang, MSM¹

Affiliation: ¹The Fourth Affiliated Hospital of Anhui Medical University, Xinzhan District, Hefei, Anhui, China; ²The First Affiliated Hospital of Anhui Medical University, Shushan District, Hefei, Anhui, China

Correspondence: Linsen Fang, MSM, Department of Wound Repair, Plastic and Aesthetic Surgery, The Fourth Affiliated Hospital of Anhui Medical University, No. 100 Huaihai Rd, Xinzhan District, Hefei, Anhui 230000, PR China; shaoshangke@126.com

Disclosure: The authors disclose no financial or other conflicts of interest.