A Sentinel Lymph Node Biopsy (SLNB) is a common surgical procedure performed as part of cancer staging, typically for breast cancer or melanoma, to determine if cancer cells have spread to the lymph nodes. During the procedure, surgeons identify and remove the first one or two lymph nodes—the sentinel nodes—that drain the area of the tumor. While the procedure is less invasive than a full lymph node dissection, it requires an incision in the armpit (axilla). Pain and discomfort in this area are entirely expected and are a normal consequence of the body’s healing process following surgical disruption.
The Source of Post-Surgical Pain
The pain experienced in the armpit following an SLNB is primarily a direct result of tissue manipulation and the body’s attempt to repair the surgical site. To access and remove the sentinel nodes, the surgeon must navigate through layers of muscle, fat, and connective tissue within the axilla. This necessary disruption causes immediate trauma to the local area, which the body registers as post-operative pain.
A major anatomical contributor to the discomfort is the intercostobrachial nerve (ICBN). This sensory nerve runs through the armpit and provides sensation to the skin of the upper, inner arm and the axilla. Although surgeons take great care to preserve this nerve, it is often stretched, bruised, or partially severed during the procedure due to its proximity. Damage to the ICBN causes a distinct type of nerve pain and sensory change in the affected areas.
As the surgical wound heals, the body forms scar tissue, a dense fibrous material, to bridge the incision and repair the deeper tissues. This process, known as fibrosis, can cause tightness and restricted movement in the axilla and shoulder. The scar tissue can also press on surrounding nerves, leading to ongoing localized pain and a feeling of pulling or stiffness.
Identifying Different Types of Axillary Discomfort
Pain after an SLNB can be categorized by its timing and sensory characteristics. Immediately following the procedure, patients experience acute post-operative pain, which is typically a dull ache or soreness managed with standard pain medication. This localized pain generally subsides significantly within the first few weeks as the incision heals.
A distinct form of discomfort that can arise is Axillary Web Syndrome (AWS), often referred to as “cording.” This condition involves the development of taut, cord-like bands of tissue that can extend visibly from the armpit down the arm. AWS is caused by inflammation and hardening within the lymphatic or venous structures and can severely restrict the arm’s range of motion, causing a painful, pulling sensation.
If pain persists for more than three to six months after the surgery, it may be classified as chronic pain, sometimes referred to as Post-Mastectomy Pain Syndrome (PMPS). This chronic condition is often neuropathic, meaning it stems from damaged nerves, such as the ICBN. Patients frequently describe this pain as burning, shooting, stabbing, or tingling sensations, sometimes accompanied by numbness (paresthesia) or hypersensitivity to touch in the armpit and upper arm.
Managing Discomfort and Promoting Healing
Managing post-surgical armpit discomfort requires a combination of medical and physical interventions focused on reducing inflammation and restoring mobility. For acute pain and general soreness, over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are often recommended to reduce pain and swelling at the surgical site. If the pain includes neuropathic symptoms like burning or shooting sensations, specialized medications such as gabapentinoids (e.g., gabapentin or pregabalin) may be prescribed, as they work directly on nerve signals to calm the pain.
Physical therapy is a cornerstone of recovery, focusing on gentle range-of-motion exercises to prevent stiffness and reduce the impact of fibrosis. These exercises should be initiated as advised by the care team, often starting with small, pendulum-like motions to maintain shoulder and arm flexibility without straining the incision. Maintaining proper posture and using the affected arm for normal daily activities also helps encourage movement.
Once the incision is fully closed and healed (typically two to three weeks after surgery), scar massage can begin to address the underlying fibrosis. This technique involves using firm but gentle pressure to move the scar and the underlying tissue in circular, linear, and cross-friction motions. Massaging the scar helps to break down dense scar tissue, which improves mobility, reduces tightness, and can desensitize the area.
When to Seek Immediate Medical Attention
While some pain and swelling are expected after an SLNB, certain signs indicate a potential complication that requires prompt medical evaluation. A sudden and uncontrolled increase in pain, especially if it is not relieved by prescribed medication, should be reported immediately. This change in pain level can signify a deeper issue developing at the surgical site.
Signs of infection are a primary concern and necessitate immediate contact with the healthcare team. Patients should also be vigilant for signs of lymphedema, characterized by the rapid onset of swelling in the arm, hand, or chest on the side of the surgery.
- Fever greater than 101°F (38.3°C).
- Significant and worsening redness or warmth around the incision.
- Unexpected drainage, particularly thick or foul-smelling discharge.
- Sudden or excessive swelling that does not resolve with elevation.
- Any signs of excessive bleeding from the incision.