Evaluating Impact of NIRAF Detection for Identifying Parathyroid Glands During Parathyroidectomy (NIRAF)

Evaluating Impact of Near Infrared Autofluorescence (NIRAF) Detection for Identifying Parathyroid Glands During Parathyroidectomy

This study describes a single center, randomized, single-blinded clinical trial to assess the clinical benefits of the use of near infrared autofluorescence (NIRAF) detection with an FDA-cleared device 'Parathyroid Eye (PTeye)' for identifying parathyroid glands (PGs) during parathyroidectomy (PTx) procedures. It compares risk-benefits and outcomes in PTx patients where NIRAF detection with PTeye for parathyroid identification is either used or not used.

Inability of the surgeon to identify or localize the diseased PG can occur in 5 - 10% of cases resulting in failed parathyroidectomies (PTx). As a result, persistent hyperparathyroidism can occur in these patients resulting in unnecessary repeat surgeries that may be associated with increased morbidity and costs. Ultrasound imaging, 99mTechnetium-sestamibi scintigraphy, and computed tomography (CT) have so far demonstrated variable efficacy in preoperative localization of diseased PGs and may not always correlate well with the surgical field of view as observed intraoperatively. Consequently, most surgeons rely on visual identification of PGs during surgery, whereby the accuracy of PG identification is eventually determined by her/his surgical skill and experience. When in doubt, a surgeon routinely confirms the identity of PG tissue intraoperatively by sending the specimen for frozen section analysis that typically requires a wait time of 20-30 minutes per sample and has additional costs. By easily being able to distinguish parathyroid from other tissues intraoperatively, postsurgical complications and associated costs may be reduced. The unique discovery of near infrared autofluorescence (NIRAF) in parathyroid tissues demonstrated that optical modalities that detect NIRAF can be utilized for non-invasive and label-free identification of parathyroid tissues with an accuracy as high as 97%. Since then, several research groups have explored the feasibility of localizing parathyroid glands using NIRAF detection with reasonable success, resulting in FDA clearance for marketing this optical technique. In this study, we plan to evaluate whether an FDA-cleared device called 'PTeye' (AiBiomed, Santa Barbara, CA) is beneficial or not, for the surgeon and patient during PTx operations. The results of such a study will help us to understand and assess the true impact of optical modalities such as PTeye on (i) improving the quality and efficiency of PTx surgeries and (ii) minimizing risk of postsurgical complications and related expenses. The aim of this prospective single blinded randomized study is to compare 2 groups of patients: PTx patients operated using NIRAF detection technology with PTeye as adjunct tool (NIRAF+) vs. patients operated without the adjunct technology (NIRAF-). The main objective of this study is to assess the benefit of intraoperative use of NIRAF detection technology via PTeye during PTx procedures with regard to PG identification, duration of surgery, number of frozen section analysis performed, number of intraoperative PTH assays sent and incidence of postsurgical complications, if any and history of ER visits or hospitalization or repeat surgeries due to persistent high blood calcium after PTx procedure, compared to standard of care.

Parathyroid Adenoma, Parathyroid Neoplasms, Parathyroid Hyperplasia, Parathyroid Cancer, Hypercalcemia, Primary Hyperparathyroidism

Parathyroidectomy, Intraoperative Parathyroid Identification, Near Infrared Autofluorescence, Persistent Hyperparathyroidism, Persistent Hypercalcemia, Failed Parathyroidectomy, Repeat Parathyroidectomy

NIRAF detection technology is used as an adjunctive tool for intraoperative parathyroid identification in patients who undergo parathyroidectomy (PTx) in the interventional group. Generic Name of Device: Parathyroid Autofluorescence Detection Device (NIRAF detection technology). The Parathyroid Autofluorescence Detection Device consists of a disposable fiber-optic probe that emits non-ionizing radiation from a near infrared (NIR) 785 nanometer (nm) laser source, and also transmits the resulting tissue NIRAF to a photo-detector. The 785 nm laser source emits a maximum power of 20 milliwatts (mW). The device has an FDA clearance for clinical use in general surgeries and dermatological use (Class 2 device).

Parathyroid gland identification will be performed with PTeye using NIRAF detection technology as an adjunctive tool in patients who undergo parathyroidectomy (PTx).

Parathyroid gland identification will be performed with the naked eye of the surgeon without using PTeye - NIRAF detection technology in patients who undergo parathyroidectomy (PTx).

Near Infrared Autofluorescence (NIRAF) detection technology or 'PTeye' consists of a disposable fiber-optic probe that emits non-ionizing radiation from a NIR 785 nm laser source, and also transmits the resulting tissue NIRAF to a photo detector. The 785 nm laser source emits a maximum power of 20 mW. The device is FDA cleared for clinical use in general surgeries and dermatological use (Class 2 device). After surgeon identifies a potential parathyroid gland in the surgical field, the surgeon places the fiber-optic probe of PTeye on suspect tissue and presses the device foot-pedal to activate tissue NIRAF measurement. Auditory beep at high frequency with a Detection Ratio > 1.2 is interpreted by device as the suspect tissue being positive for parathyroid.

Failure of intra-operative parathyroid hormone (PTH) to normalize (defined as failure of PTH to drop > 50% of its baseline value at final intra-operative PTH assay and/or failure of PTH to drop < 65 pg/ml or 6.9 pmol/L).

Elevated blood calcium levels (total blood calcium level > 10.5 mg/dL or 2.6 mmol/L) with/without elevated parathyroid hormone (PTH) (serum intact PTH > 65 pg/ml or 6.9 pmol/L) at first postoperative visit.

If blood calcium with/without parathyroid hormone (PTH) has not normalized at 1st post-operative visit, calcium and/or PTH is subsequently measured as necessary. Patient is defined to have a failed parathyroidectomy if hypercalcemia/hyperparathyroidism (defined as total blood calcium level > 10.5 mg/dL or 2.6 mmol/L, with/without elevated serum intact PTH > 65 pg/ml or 6.9 pmol/L) persists at or after the 6th postoperative month.

Overall number of parathyroid glands identified (Experimental Group: Glands identified with naked eye + NIRAF; Control Group: Glands identified with naked eye)

Number of frozen sections sent for analysis during the procedure to confirm potential parathyroid tissue

Number of diseased parathyroid glands identified intra-operatively versus glands localized preoperatively using sestamibi, CT or ultrasound

Duration taken to identify 1st parathyroid gland in PTx procedure - timed from skin incision to finding PG.

Duration taken to identify last parathyroid gland in PTx procedure - timed from skin incision to finding the last PG.

Duration of PTx procedure - timed from skin incision until the surgeon notifies the anesthesia team to awaken the patient

Time taken for PTH to attain cure criteria or normalize - timed from skin incision until the PTH levels drops > 50% of its baseline value and/or PTH drops < 65 pg/ml or 6.9 pmol/L.

Number of tissues that were excised by surgeon assumed to be parathyroid tissue, but is later validated as non-parathyroid tissue (false positive) by histology

Number of doctor visits/emergency department visits or hospital admissions due to persistent hypercalcemia and/or associated symptoms after parathyroidectomy procedure

Inclusion Criteria: All primary hyperparathyroidism patients eligible for parathyroidectomy (PTx). Both bilateral and focused mode of PTx will be considered for this study, based on the surgeon's preference. Re-operative primary hyperparathyroidism patients who have undergone a failed prior PTx. Exclusion Criteria: Patients with concurrent parathyroid and thyroid disease that require total thyroidectomy. Patients with secondary or tertiary hyperparathyroidism.

Informed Consent Form and Clinical Study Report will be made available to other researchers as per the specified time-frame

Clinical Study Report will be shared 6 months after publication of trial data and will be available till end date of trial. Informed Consent Form will be shared for a year after the primary completion date of the trial.

Request for Individual Patient Data (IPD) - Informed consent Form and Clinical Study Report - will be reviewed by the principal investigator of this clinical trial, before granting access to IPD

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