Overview

Definition:
-The thyroid posterior suspensory ligament, also known as the ligament of Grateloup or Berry's ligament, is a condensation of connective tissue that attaches the posterior aspect of the thyroid lobe to the cricoid cartilage, typically at the level of the cricothyroid joint
-It is distinct from the anterior suspensory ligaments which attach to the tracheal rings.
Anatomy Relation: This ligament plays a crucial role in the vascularization and innervation of the thyroid gland, as it often encloses or is intimately associated with the inferior thyroid artery and the recurrent laryngeal nerve.
Clinical Significance: Accurate identification and careful handling of the thyroid posterior suspensory ligament are paramount in thyroid surgery to prevent significant intraoperative and postoperative complications, particularly recurrent laryngeal nerve injury and uncontrolled hemorrhage from the inferior thyroid artery.

Surgical Anatomy

Location:
-Located at the posterior-medial aspect of the thyroid lobe, anchoring it to the larynx
-It is deep to the thyroid parenchyma.
Relationships:
-Closely associated with the cricothyroid muscle and membrane
-The recurrent laryngeal nerve typically passes posterior or within its substance
-The inferior thyroid artery branches are usually found near or within this ligamentous structure.
Variations:
-The exact thickness, extent, and adherence of the ligament can vary significantly between individuals
-In some cases, it may be less distinct, while in others it can be a robust fibrous band.

Identification Techniques

Dissection Plane:
-Development of a dissection plane between the thyroid lobe and the prevertebral fascia is essential
-The posterior suspensory ligament represents a key landmark at this interface.
Blunt Dissection: Gentle blunt dissection can help delineate the ligament, but care must be taken not to avulse the associated neurovascular structures.
Ligature And Division:
-Once identified, the ligament is typically ligated proximally to control bleeding from the inferior thyroid artery branches and then divided
-This allows for mobilization of the thyroid lobe.
Nerve Preservation:
-Meticulous identification of the recurrent laryngeal nerve prior to or during the division of the ligament is critical
-The nerve is often found in close proximity and can be injured by aggressive dissection or improper ligation.

Surgical Indications

Thyroidectomy: Total thyroidectomy and hemithyroidectomy for benign or malignant thyroid neoplasms are the primary indications for dissecting and dividing the posterior suspensory ligament.
Goiter Management: Large substernal goiters or multinodular goiters requiring surgical reduction or removal.
Thyroid Biopsy: In cases where a large or deeply embedded nodule requires surgical biopsy or excision.

Complications And Prevention

Hemorrhage: Hemorrhage from the inferior thyroid artery or its branches is a significant risk if the ligament is divided without adequate proximal ligation.
Recurrent Laryngeal Nerve Injury: Nerve paralysis or paresis leading to vocal cord dysfunction can occur due to direct injury, thermal injury, or stretching during ligament dissection.
Hypoparathyroidism: Damage to or devascularization of the parathyroid glands, which are often located in the vicinity of the posterior aspect of the thyroid, can lead to hypocalcemia.
Prevention: Careful anatomical dissection, liberal use of magnification (loupes or microscope), meticulous identification and preservation of the recurrent laryngeal nerve and parathyroid glands, and precise ligation of vascular pedicles are key preventive measures.

Key Points

Exam Focus: Understanding the anatomical relationships of the posterior suspensory ligament to the recurrent laryngeal nerve and inferior thyroid artery is crucial for DNB and NEET SS surgery exams.
Clinical Pearls:
-Always visualize the recurrent laryngeal nerve before dividing any posterior structures
-Consider the ligament as a neurovascular bundle to be carefully dissected and managed.
Common Mistakes:
-Aggressive, blind dissection of the posterior aspect of the thyroid
-Failure to identify the nerve before ligament division
-Inadequate ligation of the inferior thyroid artery branches.