In kidney failure, phosphate accumulation leads to hyperphosphatemia, and reduced 1,25-dihydroxyvitamin D3 production in the kidneys results in hypocalcemia. Calcium levels decrease further due to reduced dietary intake and absorption. Hypocalcemia and hyperphosphatemia together stimulate parathyroid hormone (PTH) secretion. The suppressive effects of calcium and vitamin D on the parathyroid glands are diminished to varying degrees. Additionally, in uremic cases, the suppression of parathyroid glands is also impaired1.
Secondary hyperparathyroidism (sHPT) associated with chronic kidney failure is called renal osteodystrophy. While calcium and vitamin D3 treatments may initially suffice for sHPT, surgical intervention becomes necessary over time. Subtotal parathyroidectomy is one of the standard surgical approaches for treating sHPT caused by kidney failure, although there is no complete consensus on the best method1,2.
This study aims to retrospectively analyze cases of sHPT operated on in our clinic due to chronic kidney failure and evaluate our surgical indications in light of the literature.
Materials and Methods
From November 2006 to November 2010, 34 patients who underwent subtotal parathyroidectomy and cervical thymectomy for sHPT due to chronic kidney failure at Şişli Etfal Training and Research Hospital’s 2nd General Surgery Clinic were retrospectively analyzed. Among these, 18 were female and 16 were male, with a mean age of 53.6 years (range: 23–75). Of the patients, 25 were on hemodialysis, and 9 were on continuous ambulatory peritoneal dialysis (CAPD).
Before surgery, all patients underwent routine blood counts, serum calcium, phosphate, sodium, potassium, chloride, magnesium, alkaline phosphatase (ALP), PTH, total protein, and albumin level assessments. Parathyroid ultrasound and 99mTc sestamibi scintigraphy were used to image the parathyroid glands preoperatively.
Renal osteodystrophy was evaluated using total ALP values and bilateral hand X-rays. Bone mineral densitometry was performed for cases where bone disease could not be fully assessed. Surgical indications were based on criteria established by the National Kidney Foundation of the USA (Table 1)3. Standard bilateral cervical exploration was performed on all patients. Enlarged glands over 1 cm detected by ultrasonography or scintigraphy were carefully excised to avoid leaving behind autonomous tissue. All patients underwent cervical thymectomy.
Findings
Surgical treatment was indicated for patients with refractory hypercalcemia and/or hyperphosphatemia unresponsive to medical therapy and PTH levels >800 pg/mL. All patients had elevated PTH levels, with a mean of 2111.85 ± 1096.59 pg/mL (range: 253–4570 pg/mL; normal range: 15–65 pg/mL). Serum calcium levels averaged 10.85 ± 0.89 mg/100 mL (range: 8.5–10.5 mg/100 mL). Preoperative hypercalcemia was present in 23 patients (67.6%). Serum phosphate levels averaged 5.17 ± 1.74 mg/100 mL (range: 2.3–10 mg/100 mL; normal range: 2.7–4.5 mg/100 mL). Mean ALP levels were 439.15 ± 227.31 IU/L (range: 70–991 IU/L; normal range: 40–129 IU/L).
Of the patients, 33 had elevated PTH levels, 27 had hypercalcemia, and 24 had hyperphosphatemia. Muscle weakness and bone pain were the most common symptoms, reported in 25 patients (74%) and 19 patients (55%), respectively. Radiological examinations showed subperiosteal resorption in 15 patients (44%) and spontaneous fractures in 6 patients (17.6%). One patient had calciphylaxis, with necrosis developing after nail removal due to subungual infection. The lesion, accompanied by severe pain, regressed post-parathyroidectomy.
Among hemodialysis patients, the average dialysis duration was 5.8 years (range: 3–8 years), while CAPD patients had an average duration of 4 years (range: 3–5 years). Seven patients had osteoporosis identified via bone densitometry.
All but one patient underwent subtotal parathyroidectomy and thymectomy. One patient with a history of subtotal thyroidectomy had 3 hyperplastic glands removed, and normocalcemia was achieved postoperatively. Four patients with thyroid nodules detected preoperatively also underwent thyroidectomy (3 total, 1 near-total thyroidectomy).
Postoperative follow-up averaged 23.5 months (range: 1–42 months). No recurrent laryngeal nerve injuries occurred, and only one patient developed a wound infection. Hypocalcemia occurred in 27 patients (79%) postoperatively, managed with oral and intravenous calcium and vitamin D supplements. Permanent hypoparathyroidism developed in 2 patients (5.8%).
Muscle weakness and bone pain symptoms improved significantly post-surgery. Reoperations were performed for persistent hyperparathyroidism due to remnants and recurrence due to a supernumerary gland. Normocalcemia was achieved postoperatively in both cases.
Discussion
The relationship between CKD and sHPT was first described by Albright in 1934, and elective subtotal parathyroidectomy was first reported by Stanbury et al. in 19604. Subsequent developments introduced total parathyroidectomy with autografting and subtotal parathyroidectomy as standard procedures5,6. Despite advancements in medical treatments such as vitamin D analogs and calcimimetics, surgical intervention remains necessary for some sHPT cases7.
Persistent or recurrent sHPT often results from supernumerary or ectopic parathyroid glands. Careful exploration and thorough cervical thymectomy are essential to minimize these risks8,9. Our findings align with the literature, demonstrating significant improvements in skeletal symptoms and reduced recurrence rates postoperatively.
Effective medical management and patient compliance are critical for reducing severe skeletal symptoms preoperatively. Surgical intervention provides a definitive solution for patients with refractory sHPT, significantly improving quality of life and laboratory parameters.
