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Figure 6-6. A, Band keratopathy seen in the eye of a patient with secondary hyperparathyroidism. B, Cutaneous ulceration owing to hypercalcemia.

Subtotal parathyroidectomy and total parathy-roidectomy with autotransplantation of parathyroid tissue into the forearm are the procedures of choice for patients with secondary HPT (Figure 6-8). We prefer subtotal parathyroidectomy, leaving 50 mg of parathyroid tissue for compliant patients who will take vitamin D (calcitriol [Rocaltrol]), phosphate binders, and calcium. During exploration, all four hyperplastic glands should be identified, and about 20% of patients may have a fifth parathyroid gland. In both procedures, a transcervical thymectomy should also be performed to remove any supernumerary parathyroid glands or embryogenic nest of parathyroid tissue.

While performing a subtotal parathyroidectomy, 31/2 of the 4 glands are resected. Approximately 50 mg of the most normal of the hyperplastic parathyroid glands that is not situated on the recurrent laryn-geal nerve is left in place with its vascular pedicle intact and marked with a clip or stitch. The viability of the remnant gland should be ensured prior to removing the hyperplastic glands. We also recommend cryopreservation of parathyroid tissue for all patients who have a subtotal parathyroidectomy resection or a total parathyroidectomy with autotransplantation. Care is taken to avoid transplanting tissue from macroscopically visible nodules.2 One should

Figure 6-7. Parathyroid gland greater than 1 cm seen on sonogram.

Figure 6-6. A, Band keratopathy seen in the eye of a patient with secondary hyperparathyroidism. B, Cutaneous ulceration owing to hypercalcemia.

Table 6-4. INDICATIONS FOR SURGICAL TREATMENT*

Clinical

Laboratory

Bone pain, spontaneous bone fractures Severe pruritus Extensive soft tissue calcifications (tumoral calcinosis) Calciphylaxis Parathyroid gland > 1 cm General weakness

Ca x PO4 product > 70

Ca > 11 mg/dL Alkaline phosphatase > twofold increased

*Also symptoms and complications listed above. Ca = calcium; PO4 = phosphorous.

also avoid fracturing parathyroid glands to decrease the risk of parathyroid hyperplasia. If renal transplantation is anticipated, the remnant should be larger (40 to 60 mg) to avoid post-transplant hypoparathyroidism. The major advantage of subtotal parathyroidectomy is knowing the location of the remaining parathyroid gland. Postoperative hypoparathyroidec-tomy is less common. The disadvantage of subtotal resection is that a second neck exploration is needed in the event of persistent or recurrent HPT.5

Total parathyroidectomy and parathyroid gland autotransplantation to the forearm are preferred by some surgeons. They decrease the need for a second neck exploration, although some patients have persistent or recurrent secondary HPT owing to failure to remove a supernumerary parathyroid gland in the neck or superior mediastinum. During transplantation, the autograft is left in iced physiologic saline at 4°C for 30 minutes and sliced into 1 x 1 mm pieces. Twelve to 20 of these slices are then transplanted into the brachioradial muscle bed through a single incision in the nondominant forearm. Each implant is located in a separate small pocket and secured with a permanent suture mark. Some parathyroid tissue should also be cryopreserved (Figures 6-8).

There is much debate regarding routine bilateral neck exploration in multiple endocrine neoplasia (MEN) or secondary HPT. A recent study by Chou and colleagues assessed intraoperative PTH monitoring during surgery for secondary HPT.19 They anticipated that because total or subtotal parathyroidectomy is needed for successful treatment of secondary HPT or MEN, the 50% decline in PTH levels used in estimating an appropriate treatment response in primary HPT may be inadequate. They found that complete surgical removal can be ensured if levels are less than 60% that of baseline at 10 minutes.

Postoperative calcium and 1,25-dihydroxyvita-min D replacement is important as the PTH secretion from the autografted parathyroid tissue is insufficient for at least 3 weeks. For all patients with secondary HPT, treatment with vitamin D3, calcium, and phosphate binders is necessary to prevent recurrent hyperplastic and secondary HPT.20 In the case of recurrent or persistent HPT, determination must be made whether the condition is attributable to a missed gland in the neck or a hyperfunctioning forearm graft. To ascertain this, venous sampling from both arms should be obtained. If the level is high in only one arm (ie, a twofold increase versus the non-transplanted arm), one may surmise that a hyper-functioning graft is the cause (see Figure 6-8).5

Patients with symptomatic secondary HPT and osteoporosis should have early parathyroidectomy

Figure 6-8. Autotransplantation of parathyroid tissue. A, Autograft parathyroid tissue sliced into 1 x 1 mm pieces, and B, transplanted into the nondominant forearm.

to prevent the morbidity of bone fracture. Parathyroidectomy and autotransplantation can improve the bone mineral density of symptomatic secondary HPT at both the lumbar spine and femoral neck.21 Sexual dysfunction is common in chronic renal failure, with nearly half of uremic men complaining of erectile dysfunction. It is hypothesized that an excess of PTH in uremic patients may contribute to hormonal disturbances and the impotence of uremia. Parathyroidectomy with autotransplantation improved sexual function, frequency of attempted intercourse, satisfaction of attempted intercourse, and enjoyment of intercourse in men with previously symptomatic secondary HPT.22 It was postulated that the improved sexual function was related to reduced prolactin in association with decreased calcium, phosphorus, and PTH.

Calciphylaxis is a rare, life-threatening condition in secondary HPT, characterized by vascular calcification in the tunica media of blood vessel walls. Such calcifications create painful violaceous mottled skin lesions of the upper and lower extremities, which may progress to ischemic necrosis. Gangrene of the digits often requires amputation, leading to poor wound healing and possibly sepsis and death.23,24 Associations have been seen with high serum calcium phosphate product and severe secondary HPT, but it may occur in patients with normal or mildly elevated serum phosphate of PTH levels.25 The only potential curative therapy in this situation is prompt parathyroidectomy. Palliative interventions include focal wound care, antimicrobials, phosphate binders, and avoidance of vitamin D load.23,24 A recent study of patients with calciphy-laxis revealed that there was resolution of pain and healing of cutaneous wounds in all patients treated with surgery. However, five of seven patients treated with medical therapy alone died of complications from calciphylaxis, including gangrene and sepsis. Patients with surgery had a significantly longer median survival than those who did not—36 months versus 3 months, respectively.24

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