Carotid Body Tumor - Surgical Management

Introduction

Carotid body tumors (CBTs), also known as chemodectomas, are very uncommon or rare tumors arising from the paraganglionic tissue (nerve tissue) at the carotid bifurcation (the junction of the artery where it divides into two branches). These tumors present a unique surgical challenge due to their intricate anatomical location and potential for significant involvement of the blood vessels. The prevalence of CBTs is around 60 percent of the total head and neck paragangliomas. These tumors are more commonly seen in females as compared to males. The most commonly affected age group is individuals with more than 20 years of age. This article provides a comprehensive review of the surgical management of CBTs, encompassing preoperative evaluation, surgical techniques, perioperative considerations, and postoperative care.

What Are Carotid Body Tumors?

A carotid body tumor is a tumor that is highly rich in blood vessels. The tumor starts from the division of the carotid body. These tumors are no-cancerous in nature and grow slowly over time and can result in compression of the underlying structures as they grow in size. According to the published literature, around ten percent of carotid tumors carry a malignant (to turn into cancerous lesion) tendency. Carotid body tumors are of three types:

• CBT Type I - Localized variant.

• CBT Type II- Partially wrapped type tumor.

• CBT Type III- Completely wrapped variant.

What Are the Symptoms of Carotid Body Tumors?

• Loss of sensation in the tongue.

• Sore throat.

• Dysphagia (difficulty in swallowing).

• Hoarseness of voice.

• Formation of a palpable lump in the neck, which may be non-tender on palpation.

How Is Carotid Body Tumor Surgery Performed?

The steps followed during carotid body tumor surgery are:

Preoperative Evaluation: A detailed preoperative evaluation of the tumor should be performed to rule out the size and extent of the tumor. A radiographic analysis such as CT (computed tomography) helps in determining the exact size and location of the tumors and their anatomical association with underlying vital structures (arteries and veins). Angiography can also be done to determine the vascularity of the tumor and its association with the carotid arteries.

Surgical Procedure: Surgical removal of CBT is the gold standard method for the management of these tumors. The surgery is mostly performed under GA (general anesthesia).Various surgical approaches are used to surgically remove the carotid body tumor, such as transcervical, trans parotid, and endoscopic-assisted approaches. The choice of the surgical procedure depends on several factors, such as

1. Size of the tumor.

2. Anatomical position of the tumor.

3. Association of tumors to the underlying vital structures (artery, nerves, and vessel).

4. Extent of the tumor.

Regardless of the technique selected, preservation of the cranial nerves and carotid arteries is a primary goal to mitigate the risk of any postoperative complications associated with the surgery.

• Surgical Incision: After the administration of GA, an incision (cut) is made around the front border of the sternocleidomastoid muscle (muscles of the neck).

• Surgical Dissection: The dissection (separation of the muscles layer by layer) is then performed to assess the carotid sheath (outer covering of the carotid body). The carotid sheath is then opened. After opening the carotid sheath, the common facial vein is divided, and laryngeal nerves (nerves to the voice box) are preserved, followed by mobilization of the common carotid artery. The XII cranial nerves (hypoglossal nerve - nerve supplying to the tongue) are protected and separated.

• Surgical Removal of the Tumor: If the tumor is small (Shamblin group I), the external carotid artery (ECA) and its branches are preserved, and the tumor mass is removed carefully after mobilizing the tumor completely. However, in cases of larger tumors (Shamblin group II), which are adhered to the carotid vessels, the ECA is preserved but separated at its origin, and the proximal stump is stitched firmly to minimize any blood loss and provide a strong handle to rotate the tumor, which significantly helped in the dissection process. In cases of very large tumors (Shamblin group III) where dissection and separation of the tumor from the carotid artery is not possible, both ECA and internal carotid artery (ICA) are sacrificed. Neurovascular reconstruction using the graft ( a piece of healthy living tissue or bone) with a shunt is performed along with clamping of carotid arteries.

• Follow-Up: The blood pressure and the assessment of the nerve function is done after the surgery. After 24 hours the drain is usually removed. Patient is administered heparin after the surgical procedure. Patients are monitored continuously for their vitals.

What Are the Post-Operative Care After Carotid Body Tumor Surgery?

After the surgical removal of the CBT, patients should be monitored closely to evaluate any postoperative complications if any. A few associated postoperative complications are:

1. Neck stiffness.

2. Shoulder dysfunction.

3. Recurrence of the tumor.

4. Surgical site infection.

5. Vascular complications such as bleeding.

6. Cranial nerve damage leading to numbness or loss of sensation in tongue and other areas.

7. Delayed wound healing.

8. Neck hematomas (collection in blood in extravascular space).

Early mobilization and physical therapy may help prevent postoperative complications. Regular and thorough monitoring for tumor recurrence or residual disease is essential after CBT resection. Long-term follow-up with serial imaging studies is vital for early detection and treatment of any issues. Moreover, patients should be informed about the potential long-term consequences of the procedure, so they can make informed decisions and take necessary precautions to ensure their well-being.

Prognosis and Clinical Outcomes

The prognosis for carotid body tumor surgery is generally favorable with high rates of tumor control and preservation of neurological function. Long-term follow-up is crucial to detect tumor recurrence and late complications, particularly in patients with genetic predispositions or multifocal disease. Multidisciplinary collaboration of neurologist (specialist in nervous system disease), anesthesiologist, and vascular surgeons and advances in surgical techniques contribute to improving patient outcomes and minimizing morbidity associated with CBT resection.

Conclusion

Surgical management of carotid body tumors represents a challenging yet essential aspect of the multidisciplinary approach to treating these rare neoplasms. By employing a systematic approach to preoperative evaluation, selecting appropriate surgical techniques, and optimizing perioperative care, healthcare providers can achieve favorable outcomes while minimizing the risk of complications. Continued research and advancements in surgical techniques and perioperative management are necessary to further improve the safety and efficacy of carotid body tumors resection.