Tuesday, October 25, 2011

Review - Recurrent/Persistent Primary Hyperparathyroidism

R. Udelsman. J Clin Endocrinol Metab, October 2011, 96(10):2950 –2958
Excellent review from JCEM here.

Useful extracted quotes:
  • Persistent 1°HPTH accounts for the vast majority of patients who require reexploration.

  • The most common cause of persistent 1°HPTH is surgeon inexperience in locating and adequately excising a parathyroid adenoma. Although a subset of these retained glands will eventually be located in ectopic locations, the majority are eutopic and accessible by repeat cervical exploration.

  • Recurrent 1°HPTH implies that the patient had an initial successful operation, maintaining normal serum PTH and calcium levels for at least 6 months postoperatively,
  • and then developed recurrent disease.

  • Other causes of an elevated serum PTH must be considered. These include mild degrees of secondary HPTH due to renal insufficiency, a renal calcium leak, gastrointestinal tract abnormalities, vitamin D deficiency, as well as a variety of other rare causes.

  • There are no published guidelines directly applicable to the indications for reoperative parathyroid surgery. It is reasonable to extrapolate recommendations employed for
  • the unexplored patient with the caveat that the threshold for surgical exploration should be higher due to the inherent difficulty encountered in the reoperative patient.

  • Imaging can be broadly divided into noninvasive and invasive studies. The noninvasive studies include ultrasound, technetium 99m sestamibi scans [preferably employing single photon emission computed tomography (CT)], CT scans [preferably four-dimensional (4-D)], occasionally MRI scans, and in some institutions fusion studies including sestamibi-CT scans (11, 12). Invasive studies encompass ultrasound-guided PTH aspiration and angiographic procedures including arteriography and venous sampling for PTH, preferably with on-site PTH analysis to guide the angiographers (13).

  • All of the imaging studies are less reliable in the redo neck, and false-positive and false-negative results are frequently encountered.

  • The reoperative neck poses significant technical challenges due to scar formation and distorted anatomy that make it more difficult to identify and safely remove abnormal parathyroid glands. In addition, the external branch of the superior laryngeal nerve and the recurrent laryngeal nerve are at increased risk of injury.

  • We and others have found the use of a rapid intraoperative PTH assay to be of critical importance in the re-operative patient.

  • The classic medial approach to the parathyroid glands mobilizing the strap muscles from their midline position by progressive lateral mobilization is generally employed in the unexplored patient. In the redo neck, these muscles become fused to the underlying thyroid gland and trachea. Hence, in the reoperative neck a lateral approach is frequently employed, mobilizing the plane between the medical border of the ipsilateral sternocleidomastoid muscle and the lateralborder of the strap muscles.

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