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Inservice Exam - 2005
Lower Extremity
(A) Achilles tendon
(B) Deep peroneal nerve
(C) Lesser saphenous vein
(D) Plantaris tendon
(E) Posterior tibial artery
The correct response is Option C.
When raising a reverse sural artery flap, the important landmarks are the lesser saphenous vein and sural nerve, which should bisect the cutaneous paddle. The blood supply to this flap depends on the medial superficial sural artery and the lesser saphenous vein with its two small accompanying arteries. The pivot point of the pedicle is typically 5 cm above the lateral malleolus, where the perforators of the flap enter a more superficial plane.
The Achilles tendons are not landmarks for raising this flap but, when exposed, are good indications for this type of flap. The deep peroneal nerve is located in the lateral compartment. The posterior tibial artery is found in the deep compartment and is not associated with this flap. The plantaris tendon is deep to the dissection of the flap.
References:
1. Hollier L, Sharma S, Babigumira E, et al. Versatility of the sural fasciocutaneous flap in the coverage of lower extremity wounds. Plast Reconstr Surg. 2002;110(7):1673.
2. Ayyappan T, Chadha A. Super sural neurofasciocutaneous flaps in acute traumatic heel reconstructions. Plast Reconstr Surg. 2002;109(7):2307.
A 53-year-old man with a comminuted fracture of the midtibia has a 4 H 3-cm defect of the midanterior surface of the leg at the level of the fracture. He currently smokes two packs of cigarettes daily. Physical examination shows no palpable dorsalis pedis pulse. Which of the following surgical interventions is the most appropriate method of reconstruction in this patient?
(A) Anterior tibialis muscle flap
(B) Below-knee amputation
(C) Gastrocnemius muscle flap
(D) Gracilis free tissue transfer
(E) Soleus muscle flap
The correct response is Option E.
The soleus muscle flap is most appropriate for reconstruction in this patient. The soleus is a bipenniform muscle; its medial head originates from the posterior tibia, and the lateral head originates from the proximal fibula. It is located deep to the gastrocnemius in the superficial posterior compartment. Blood to the medial head is predominantly supplied by the popliteal and posterior tibial arteries and the lateral head is predominantly supplied by the peroneal artery. Depending on the size of the defect, a hemisoleus muscle flap can be used to preserve flexor function.
Below-knee amputation is an option if salvage of the leg is not possible or if the extremity is insensate, particularly in older patients.
An anterior tibialis muscle flap can be used for small defects. In this patient with an absent dorsalis pedis pulse and possible injury to the anterior tibial artery, this is not an optimum choice.
For lower-extremity reconstruction, the gastrocnemius muscle flap is used for knee wounds and proximal tibial defects, the soleus for middle third defects, and free tissue transfer for distal third defects. The gastrocnemius muscle flap might not reach the defect in the middle third and therefore is not the best option. Free tissue transfer is often used for reconstruction of high-velocity injuries to avoid the use of muscle in the zone of injury. Free tissue transfer, however, is not the best option for this 53-year-old man because his history of cigarette smoking and absent pedal pulse suggest the possibility of peripheral vascular disease.
References:
1. Nahai F, Love TR. Lower extremity reconstruction: management of soft tissue defects. In: Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Vol 3. Philadelphia: Lippincott Williams & Wilkins; 1994:1773-1799.
2. Kasabian AK, Karp NS. Lower extremity reconstruction. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 1997:1031-1047.
A 53-year-old man with diabetes mellitus has a nonhealing wound over the right calcaneus. A bone scan shows increased uptake at the site of the wound. Which of the following is the most definitive diagnostic test?
(A) Bone biopsy and culture
(B) CT scan
(C) Indium scan
(D) MRI
(E) Wound biopsy and culture
The correct response is Option A.
This 53-year-old man with a nonhealing wound has most likely developed osteomyelitis of the foot, which may be caused by direct, penetrating trauma to the bone or contiguous spread from adjacent soft tissue. The calcaneus is the most common site of involvement in the foot, followed by the metatarsals and the cuboid bone. Although osteomyelitis may be suspected clinically, definitive diagnosis is accomplished with bone biopsy and culture. This can be obtained by needle aspiration of the interosseous or subperiosteal space.
Cultures of a draining wound are less accurate diagnostically than bone biopsy and culture. Findings on bone scan are nonspecific and are often positive in patients with local wound infection or cellulitis. CT scans are not used in the diagnosis of osteomyelitis. Although MRI is more accurate than bone scan, it cannot be used to establish a definitive diagnosis.
References:
1. Johnson JE, Hall RL. Management of foot infections. In: Gould JS, ed. Operative Foot Surgery. Philadelphia: WB Saunders; 1994.
2. Resnick D, Niwayama G, eds. Diagnosis of Bone and Joint Disorders. Philadelphia: WB Saunders; 1988.
A 27-year-old man develops osteomyelitis after sustaining an open fracture of the distal tibia and fibula in a motorcycle accident. Following bony debridement, there is a 9-cm segmental loss of the distal tibia. An external fixator is applied, and a muscle flap is to be used to cover the skin defect. Which of the following is the most appropriate management of the bony defect?
(A) Free fibula flap
(B) Iliac crest bone grafting
(C) Papineau bone grafting
(D) Tibiofibular synostosis
(E) Ilizarov bone lengthening
The correct response is Option A.
The most appropriate management of this patient’s bone defect is a free fibula surrounding flap. Management typically depends on the volume of the bony defect along with soft-tissue stability and vascularity. If the tissue is unstable and poorly vascularized, a regional flap or free flap is required. For most bone defects smaller than 6 cm, traditional tricortical iliac crest bone grafts can be placed beneath the muscle flap. In patients with larger defects, a vascularized bone flap, such as the free fibula flap, is required. Vascularized bone also minimizes the risk for nonunion. However, weight-bearing ambulation should not occur for many months after flap coverage to allow for healing of bone without infection.
Other sources of free vascularized bone include the iliac crest and scapula. However, the iliac crest has both inadequate length and excessive curvature, and the scapula has inadequate length and lacks the tubular depth and width of the fibula.
Papineau grafts are cancellous grafts that are used to fill the bone defect but are packed flush with the skin. These grafts are seldom used clinically and are appropriate only for defects smaller than 6 cm. Tibiofibular synostosis is not a reasonable option in a patient with osteomyelitis of the distal tibia who has compromised stability and vascularity of the soft tissue. The Ilizarov technique for bone transport is less optimal in a patient who requires a long bone segment and has soft tissue of poor quality.
References:
1. Anthony JP, Mathes SJ. Update on chronic osteomyelitis. Clin Plast Surg. 1991;18:515-523.
2. Nahai F, Love TR. Lower extremity reconstruction: management of soft tissue defects. In: Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Vol 3. Philadelphia: Lippincott Williams & Wilkins; 1994:1773-1799.
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