Which Surgeries Are Considered Major Surgeries?

September 30, 2025 •

4 min read

According to the American College of Surgeons, surgical risk is an estimation of the likelihood of an adverse event occurring as a consequence of a patient undergoing a particular surgical procedure. A major surgery is typically defined by its complexity, the degree of bodily invasiveness, and the associated risks and recovery period.

Quick Summary

Major surgeries are complex, invasive procedures involving vital organs or body cavities, requiring general anesthesia, longer hospital stays, and extended recovery. The classification is based on invasiveness, risk level, anesthesia needs, and healing time. Examples include organ transplants, cardiac operations, and joint replacements.

Key Points

Defining Characteristics: Major surgeries are defined by high invasiveness, involvement of major body cavities or vital organs, need for general anesthesia, and extensive tissue disruption.
Associated Risks: The potential for significant complications, including hemorrhage, infection, blood clots, and adverse anesthesia reactions, is a key marker of major surgery.
Extended Recovery: Recovery from major surgery requires an extended period, often including a hospital stay for monitoring and longer-term rehabilitation compared to minor procedures.
Variety of Procedures: Examples of major surgeries span multiple specialties, from cardiothoracic procedures like coronary artery bypass surgery to neurological operations such as craniotomies.
Invasive vs. Minimally Invasive: While major surgery typically involves larger incisions, some complex laparoscopic procedures might also be considered major, but the key distinction remains the extent of intervention and risk.
Preoperative Assessment: Before a major surgery, a thorough risk assessment is performed by the medical team, considering the patient's overall health, functional status, and the specifics of the planned procedure.

Major surgeries are complex, invasive procedures that carry significant risk and require a longer recovery period. Unlike minor procedures, major operations typically involve opening a major body cavity, such as the abdomen, chest, or cranium, or affecting vital organs. The factors determining if a surgery is major are multi-faceted, encompassing everything from the type of anesthesia used to the potential for complications and the anticipated recovery time.

Key Characteristics of Major Surgery

Complexity and Invasiveness

Major surgeries are extensive and technically demanding, requiring a high level of surgical skill and a specialized medical team.

Extensive Tissue Dissection: These procedures involve significant disruption of body tissues to access the surgical site. This can result in greater trauma and a longer healing process compared to minimally invasive techniques.
Exposure of Body Cavities: A key characteristic is the penetration and exposure of a major body cavity (e.g., thoracotomy for the chest, craniotomy for the skull, laparotomy for the abdomen). This access is necessary for procedures involving organs or extensive internal work.
Effect on Vital Organs: Procedures targeting vital organs, such as the heart, brain, liver, or kidneys, are almost always classified as major due to their critical function.

Anesthesia and Patient Support

Major surgeries require more intensive patient support throughout the procedure.

General Anesthesia: Patients undergoing major surgery are typically placed under general anesthesia to ensure unconsciousness and muscle relaxation throughout the procedure. This differs from the local or moderate sedation used for most minor procedures.
Vital Function Support: During the operation, patients may require assisted breathing or other support for vital bodily functions due to the procedure's duration and complexity.

Risk of Complications

The potential for serious adverse outcomes is a primary distinguishing factor for major surgery.

Infection and Blood Loss: The extensive nature of major surgery increases the risk of complications such as severe infection, excessive bleeding (hemorrhage), and adverse reactions to anesthesia.
Postoperative Concerns: The risk of blood clots (thromboembolism), pulmonary complications, and acute kidney injury is higher following major operations.

Recovery and Hospital Stay

The recovery period for major surgery is significantly longer and more demanding.

Extended Hospitalization: Most major surgeries necessitate an overnight or extended hospital stay for monitoring, pain management, and complication prevention.
Longer Recovery Time: Full recovery can take weeks to months, often requiring extensive follow-up care, physical rehabilitation, or lifestyle adjustments.

Examples of Major Surgeries

Cardiothoracic Surgery

Coronary Artery Bypass Grafting (CABG): This procedure diverts blood around blocked or narrowed arteries to improve blood flow to the heart. It is highly invasive and requires a lengthy recovery.
Heart Valve Replacement: Involves replacing or repairing heart valves that are not functioning properly.
Lung Resection: Surgical removal of part or all of a lung, often to treat lung cancer.

Neurosurgery

Craniotomy: This involves opening the skull to access the brain, often for the removal of tumors or to repair damage.
Spinal Surgery: Complex operations on the spine for issues like deformity correction or fusion.

General and Abdominal Surgery

Organ Transplant: The transplantation of organs such as the kidney, liver, or heart are among the most complex and invasive procedures.
Partial Colectomy: The removal of part of the large intestine to treat conditions like cancer or diverticulitis.
Bariatric Surgery: Procedures like gastric bypass, which alters the digestive system to facilitate weight loss, are significant and carry substantial risk.

Orthopedic Surgery

Major Joint Replacements: Surgeries like hip or knee replacement are considered major due to their invasiveness, the trauma to surrounding tissues, and the extended recovery involved.
Spine Deformity Surgery: Extensive procedures performed to correct serious spinal curvature.

Oncological Surgery

Mastectomy: The surgical removal of one or both breasts, often a part of breast cancer treatment.
Major Cancer-Related Surgery: Procedures for removing large tumors or affected organs are classified as major.

Major vs. Minor Surgery: A Comparison


Aspect	Major Surgery	Minor Surgery
Invasiveness	Highly invasive, often penetrating major body cavities.	Less invasive, typically limited to superficial tissues or small access points.
Risk Level	Higher risk of serious complications like infection, hemorrhage, and cardiac events.	Lower risk of complications.
Anesthesia	General anesthesia is typically required.	Local anesthesia or moderate sedation is often sufficient.
Equipment	Requires specialized surgical equipment and advanced operating facilities.	Uses less complex tools and can sometimes be performed in an outpatient clinic.
Recovery Time	Extended recovery period, often requiring a hospital stay and follow-up rehabilitation.	Faster recovery, with patients often returning home the same day.
Recovery Impact	Potential for lifestyle adjustments and prolonged rehabilitation.	Minimal restrictions and quicker return to normal activities.
Examples	Organ Transplant, Open-Heart Surgery, Joint Replacement, Craniotomy.	Skin Biopsy, Wart Removal, Dilation and Curettage (D&C), Cataract Surgery.

Conclusion

Understanding which surgeries are considered major surgeries is vital for patients as it informs the level of preparation and recovery needed. Key determinants include the procedure's complexity, the type of anesthesia required, the potential for complications, and the expected recovery period. Procedures involving the penetration of major body cavities, extensive dissection, and vital organs, such as open-heart surgery, organ transplants, and joint replacements, fall into this category. The distinction helps medical teams and patients properly assess risks, manage expectations, and plan for the necessary post-operative care. Patients can consult resources like the American College of Surgeons' risk calculator for more personalized information on their specific procedure.

For more detailed information on specific procedures or surgical risks, always consult a qualified medical professional.

Frequently Asked Questions

Major surgery is a complex and invasive procedure that affects vital organs or body cavities, typically requiring general anesthesia, a hospital stay, and a longer recovery time. Minor surgery is a less complex and minimally invasive procedure that involves superficial tissues, often uses local anesthesia, and has a shorter recovery period.

While general anesthesia is a strong indicator of major surgery, it is not the sole determinant. Some less complex procedures may still require general anesthesia based on factors like patient anxiety, the surgical site, or the surgeon's preference. However, the use of general anesthesia for a procedure, combined with other factors like invasiveness and recovery time, helps classify it as major.

Common major surgeries include organ transplants (kidney, liver), coronary artery bypass grafting, major joint replacements (hip, knee), craniotomy (brain surgery), and bariatric surgery. Procedures involving major cancer-related removal are also typically classified as major.

Surgical risk is assessed using various factors, including the patient's age, overall health, pre-existing medical conditions (like heart or lung disease), nutritional status, and the specific procedure's complexity. Formal scoring systems and patient history help the medical team quantify and mitigate potential risks.

The biggest risks associated with major surgery include infection at the surgical site, blood clots (thromboembolism), hemorrhage (excessive bleeding), adverse reactions to anesthesia, and cardiac or pulmonary complications.

The recovery period from a major surgery can take several weeks to months, depending on the type of procedure, the patient's health, and whether complications arise. It often involves an initial hospital stay followed by a period of rehabilitation at home or in a dedicated facility.

Not necessarily. While some less invasive but still complex procedures are now performed on an outpatient basis (e.g., some laparoscopic surgeries), most major surgeries require an overnight or extended hospital stay. The classification of major versus minor is determined by the procedure's complexity and risk, not strictly the hospital stay duration.