Long term results of Isthmus preserving total bilobectomy (IPTB) as the optimized treatment for C-cell hyperplasia
Carlo Dietl, Babette Koch, Christian Vorländer & Robert A Wahl
Background: The thyroid isthmus contains no C-cells, thus we established IPTB for cases with nodular goiter and moderate hypercalcitonemia (stimulated up to 350 pg/ml). In these cases C-Cell-Hyperplasia is the primary pathologic correlate. Exclusion criteria were pre- or intraoperative signs of malignancy.
We furthermore established IPTB as a prophylactic operation for patients with hereditary medullary thyroid carcinoma, excluding high-risk mutations.
(WJS 30 (2006): 860). Now, we report on ongoing follow-up over 7 years.
Patients and methods: From 2001 to 2007, IPTB was the definite procedure in 78 out of 107 patients with intended IPTB. Seventy with sporadic hypercalcitoninemia in nodular goiter (preop Calcitonin : 19.84 pg/ml basal, 129.72 pg/ml stimulated), 8 with hereditary MTC. The remaining 29 patients were converted to Total Thyroidectomy (TTX).
Patients were prospectively evaluated for long-term postoperative outcome, regarding recurrence of nodular goiter and C-Cell disease.
Results: No permanent RLN-palsy, 1.9% permanent Hypocalcemia occurred.
Follow-up (684 months, median 42 months) showed Calcitonin always under the measurable limit in 69 out of the 78 patients (88%) and intermittently measurable basal in the lower normal range (<10 pg/ml) in 9 patients. Those 9 patients showed no response to pentagastrin stimulation. Sonographic examinations of the isthmic remnants showed early postoperative volumes of 2 ml (median; range 1 to 5) and 2 ml (median; range 0.5 to 6) in follow-up.
One hypoechoic lesion of 0.1 ml was found after 42 months.
Substitution with L-thyroxine was lower (121±22 μg) after IPTB than after TTX (147±21 μg) (P<0.001), without a significant correlation between functional data and morphologic development of isthmic volumes.
Conclusions: By IPTB C-Cells are removed completely and permanently. The risk of recurrence of goiter (nodular, hyperplastic) or c-cell disease is low.
The basic production and regulatory function of tissue-remnants might well be of importance for many patients.