Surgical Snippets: Recent Episodes
West Virginia University Department of General Surgery
Brief surgical topics to serve as an adjunct to your ABSITE studying or medical school surgical rotation.
MARJOLIN’S ULCER Marjolin’s ulcer is a squamous cell carcinoma that arises in areas of chronic inflammation, such as old burn scars, hidradenitis, pilonidal cysts, draining osteomyelitis, and skin lesions associated with lupus. Development of this ulcer is slow, taking approximately 30 years to form in a chronic wound. Signs that a wound may have developed into squamous cell cancer are everted wound margins, sudden increase in size, excessive granulation tissue and bleeding if manipulated. Although rare, when they do develop they are aggressive and have a poor prognosis. The rate of local recurrence after treatment is 20-30%.
MERKEL CELL CARCINOMA This is a neuroendocrine tumor which is aggressive, locally invasive and has a high rate of metastasis. Five-year survival is 88% for stage 1 disease, but 0% when there are distant metastases. Order a CXR to rule out pulmonary primary tumor because tumor pathology resembles small cell carcinoma of the lung. The lesion generally appears as a red or purple papulonodule or indurated plaque. It has characteristic positive immunocytochemical staining for CK-20. Treatment is wide local excision with 1-2 cm margins with sentinel lymph node biopsy. Radiation should be performed to the primary site and nodal bed, if the latter is involved. Use of adjuvant chemotherapy is controversial if node-positive disease is discovered. The regimen in this case would be similar to that used for small cell cancer of the lung.
Squamous Cell Carcinoma of the Skin - Derived from the keratinocytes, this cancer can deeply invade surrounding structures. It generally appears as a pink, nonhealing sore with ulceration. It metastasizes to regional lymph nodes, especially in immunocompromised patients and in those with Marjolin ulcer. Regional nodal metastasis account for 80-90% of metastatic squamous cell cancer, whereas metastases to the brain, lung, liver and bone account for 10-20%. Squamous cell cancers of the mucocutaneous areas, such as the perineum, and vulva, as well as those involving the ear or scalp, have highest rates or distant metastatic involvement. Patients with distant metastases have a 10-year survival of 10%. Treatment is surgical excision with pathologically-free margins. Margins are typically 3-4mm for low-risk and 6mm for high-risk lesions. Other treatments include cryotherapy, radiation therapy, electrodessication and topical 5-FU.
Basal Cell Carcinoma - This is the most common form of skin cancer. It is locally invasive and rarely metastasizes. The main problem tends to be local recurrence in difficult to excise areas like the nose, ear and periorbital areas. Basal cell carcinomas which do metastasize have generally been neglected or have suffered multiple recurrences. Median survival in these cases is less than 1 year. Types include nodular, pigmented, morpheaform, squamous metaplasia with keratinization, and ulcerative. Treatment is surgical excision with pathologically free margins. Mohs surgery has the lowest recurrence rate. Other treatments include cryotherapy, radiation therapy and electrodesiccation.
Femoral and Popliteal Aneurysms - Due to its deep location, the popliteal artery is barely palpable in normal individuals. Prominent pulsation in the popliteal fossa is an indication that the patient may be harboring a popliteal aneurysm. Finding an aneurysm in these vessels should prompt a thorough evaluation because 50% are bilateral and 30% have an aortic aneurysm associated with them. Duplex ultrasonography can be used to confirm the diagnosis. Indications for intervention include thromboembolic complications and size. It is generally agreed that femoral aneurysms of greater than 2.5cm and popliteal aneurysms of greater than 2cm should be repaired. Here, unlike AAA’s, replacement with artificial graft is generally unnecessary, and usage of autogenous vein is feasible. Endovascular treatment with placement of covered stents that can exclude the aneurysm from the circulation is also a popular approach.
LERICHE SYNDROME – Leriche syndrome is a triad of symptoms. The first is claudication or muscular pain in the calfs, buttocks, or groin due to decreased blood flow. The second is impotence due to decreased flow in the hypogastrics and internal iliacs. The final symptom is atrophy of the lower extremities and absence or diminished femoral pulses. Occlusion in Leriche syndrome is at the level of the aortoiliac bifurcation. Ankle-Brachial Index is a reliable screening tool, however, distal pulses may be present if the obstruction is chronic enough to have allowed for collateralization. Treatment targets symptom relief. Complete occlusion may require open aorto-bifemoral bypass.
WARFARIN - Warfarin leads to deficiency of vitamin K, which is an important cofactor in certain anticoagulation factor synthesis, resulting in a decrease in production by the liver of factors II, VII, IX, and X, protein C and protein S. The drug is given orally, with the half-life of about 1.5 days, so it takes a few days to take effect and to reverse. The level of anticoagulation can be measured by checking the PT. The international normalized ratio, or INR, is an indirect measure of the PT. Because protein C and protein S lead to systemic anticoagulation, their deficiency can lead to a pro-thrombotic state. Warfarin-induced skin necrosis can occur if a patient deficient in Protein C or Protein S is given warfarin compounds. Alternately, it can occur simply because, due to their short half-lives, protein C and S are the first to decrease with warfarin administration, leading to a pro-thombotic state. For this reason, heparinization should always be performed prior to administering warfarin.
PSEUDOANEURYSMS – Pseudoaneurysms are contained arterial disruptions. The main types are traumatic and post-surgical. Traumatic pseudoaneurysms are usually iatrogenic and are a result of arterial puncture for various procedures. Because the femoral artery is the most common site for such procedures, iatrogenic pseudoaneurysms are predominantly found in this area. Post-surgical pseudoaneurysms are due to contained suture line disruptions between the arterial wall and graft material. The diagnosis can be made rapidly by duplex ultrasonography. Traumatic pseudoaneurysms greater than 2.5cm are treated by injection of thrombin, a procoagulant, in the cavity of the pseudoaneurysm under sonographic guidance. Those that do not respond to this approach will need open surgery to repair the localized disruption in the vessel wall. Asymptomatic, traumatic pseudoaneurysms less than 2.5cm do not require treatment. Post-surgical pseudoaneurysms most often require revision of the surgical site suture line.
MYCOTIC ANEURYSMS – Mycotic aneurysms result from localized infection, which may be a consequence of periaortic infectious process or due to aortic intimal seeding from bloodborne pathogens. The most common infectious bacteria are Staphylococcus aureus and Salmonella typhi, and the most common fungal agents are Candida albicans and Aspergillus fumigatus. Bacterial infections are more common than fungal infections. The usual sites are the femoral arteries and the aorta. Clinical presentation can be nonspecific but with recurrent bacteremia or fungemia. Fevers, chills, and tenderness are not attributable to size alone should prompt the physician to include an infected aneurysm in the differential diagnosis. Management is resection and repair of the aneurysm, thorough debridement of infected tissue and lifelong antibiotic treatment.
SURVIVING SEPSIS CAMPAIGN – The International Guidelines for Management of Sepsis and Septic Shock as of 2016 are as follows: Administer broad-spectrum intravenous antimicrobials for all likely pathogens within 1 hour after sepsis recognition. Obtain anatomic control as rapidly as practical. Assess patients daily for deescalation of antimicrobials; narrow therapy based on cultures and/or clinical improvement. For patients with sepsis-induced hypoperfusion, provide 30 mL/kg of intravenous crystalloid within 3 hours with additional fluid based on frequent reassessment, preferentially using dynamic variables to assess fluid responsiveness. For patients with septic shock requiring vasopressors, target a mean arterial pressure (MAP) of 65 mm Hg. Use norepinephrine as a first-choice vasopressor. Target a tidal volume of 6 mL/kg of predicted body weight and a plateau pressure of ≤30 cm H2O. Hospitals and health systems should implement programs to improve sepsis care that include sepsis screening.
Normal Saline, or 0.9% saline, is a crystalloid solution used ubiquitously for dehydration and hypovolemia. It is compatible with blood product transfusion and most medications. It is classified as an isotonic fluid, however, the concentration of NaCl is higher than found in humans at 154mEq/L of both Na+ and Cl-. There are concerns about the deleterious effects of solutions with supraphysiologic chloride concentrations. It is typically the first-line fluid used in trauma resuscitations, head injuries, acute neurologic conditions where hyponatremia should be avoided, and the treatment of mild hyponatremia.