Thoracotomy, a procedure that opens the chest cavity through the ribs, is widely considered the most painful surgery a person can undergo. Pain specialists and anesthesiologists consistently rank it at the top, with one major review in Anesthesiology Clinics stating plainly that pain after thoracotomy is “probably the most severe pain experienced after surgery.” But pain is complex, and several other procedures come close, each punishing the body in different ways.
Why Thoracotomy Tops the List
A thoracotomy involves cutting through multiple layers of muscle, then spreading or partially removing ribs to access the lungs or heart. The surgeon uses a metal retractor to pry the ribs apart, and this step alone routinely crushes the intercostal nerves that run along the underside of each rib. In many cases, the nerve is completely severed or accidentally caught in a suture when the chest is closed.
The damage doesn’t stop once the surgery ends. Every breath you take moves the surgical site, so there’s no position that offers relief. Chest tubes inserted to drain fluid further irritate the lining of the lung cavity. Ribs can fracture during retraction, and those fractures may trap nerves as they heal, creating pain that fires in response to even light touch. Neurological testing during thoracotomy has shown total conduction block in the intercostal nerve, confirming that the nerve is genuinely injured, not just irritated.
Perhaps the most striking statistic: up to 65% of thoracic surgery patients develop chronic postsurgical pain. A large 10-year study of 3,200 lung cancer patients found that 17.4% were formally diagnosed with chronic pain within three years. A separate meta-analysis reported that 57% of thoracotomy patients still had pain at three months, and 47% at six months. No other common surgery comes close to those chronic pain rates.
Other Surgeries Known for Severe Pain
A survey of over 5,700 patients found that 30% experienced moderate to severe pain 24 hours after ambulatory surgery. The procedures that consistently produced the worst pain scores were spinal disc surgery (microdiscectomy), gallbladder removal, shoulder surgery, elbow and hand surgery, ankle surgery, inguinal hernia repair, and knee surgery. These are all outpatient procedures, meaning the pain was severe enough to be notable even in surgeries where patients go home the same day.
Beyond those outpatient procedures, a few inpatient surgeries deserve special mention for the intensity and duration of their recovery pain.
Spinal Fusion
Multi-level spinal fusion, where two or more vertebrae are permanently joined together, produces pain that can escalate over the first several days rather than gradually improving. Research tracking patients hour by hour found that a specific group experienced moderate pain that continued to increase all the way through hospital discharge, typically five days after surgery, even while receiving continuous intravenous pain medication. Patients are monitored for up to 120 hours postoperatively, and the pain trajectory varies significantly from person to person, making it one of the more unpredictable recoveries to manage.
Total Knee Replacement
Knee replacement is notorious for painful rehabilitation. Average pain scores after the procedure land around 43 out of 100 on a standard pain scale, but the worst pain peaks hit 61 out of 100 in the early days. What makes knee replacement uniquely difficult is that recovery depends on aggressive physical therapy. You have to bend and strengthen the joint during the period when it hurts most, and skipping that work compromises the outcome. The combination of high baseline pain and mandatory movement is what gives this surgery its reputation.
Hemorrhoidectomy
This one surprises people. Surgical removal of hemorrhoids involves cutting tissue in one of the most nerve-dense areas of the body, and every bowel movement reopens the wound site. Up to 65% of patients report moderate to severe pain after conventional hemorrhoidectomy. The pain typically peaks during defecation and can persist for two to three weeks. There’s no way to rest the surgical area, which is what makes this relatively minor procedure feel disproportionately brutal compared to its scale.
What Makes a Surgery Painful
The procedures that rank highest for pain share a few common features. Nerve damage is the biggest driver. Surgeries that cut, crush, or stretch nerves produce sharper, more persistent pain than those that primarily affect muscle or fat. The intercostal nerve damage in thoracotomy and the nerve-rich tissue involved in hemorrhoidectomy are prime examples.
Location matters enormously. Surgeries on joints (knees, shoulders, ankles) hurt more partly because those areas are in constant motion and bear weight. Chest surgery hurts with every breath. Anorectal surgery hurts with every bowel movement. When the body can’t immobilize the surgical site, pain stays elevated longer.
The third factor is the extent of tissue disruption. Open surgeries that require large incisions, muscle cutting, and bone work consistently produce more pain than minimally invasive versions of the same procedure. A laparoscopic approach to gallbladder removal still ranks among the more painful outpatient surgeries, but it’s far less painful than the open version would be.
How Pain Management Has Evolved
The 2026 guidelines from the American Society of Anesthesiologists represent the current standard for managing pain after the most painful procedures. The strongest recommendation is for fascial plane blocks, a technique where numbing medication is injected between layers of muscle and connective tissue near the surgical site. These blocks are now strongly recommended for open chest, abdominal, and pelvic surgeries, as well as mastectomy, based on their ability to reduce both pain and the need for opioids in the first 24 hours.
For minimally invasive abdominal procedures, the same nerve blocks are also strongly recommended. For minimally invasive chest surgeries and open hernia repairs, the recommendation is conditional, meaning the evidence supports them but isn’t as robust. The guidelines also apply to children, with strong recommendations for nerve blocks after open heart or chest surgery.
The shift in pain management over the past decade has been toward combining multiple approaches (nerve blocks, non-opioid medications, and targeted local anesthesia) rather than relying primarily on opioids. This multimodal strategy doesn’t eliminate pain, but it can meaningfully lower the peak intensity during those critical first days when pain is at its worst.
Acute Pain Versus Chronic Pain Risk
The surgery that hurts most in the first 48 hours isn’t necessarily the one most likely to cause lasting problems, though thoracotomy ranks highest on both counts. Chronic postsurgical pain, defined as pain persisting beyond the normal healing window (usually three months), is a distinct condition driven primarily by nerve injury during the operation. The more nerve damage a procedure causes, the higher the risk that pain signals will continue firing long after the tissue has healed.
For thoracic surgery, that risk sits between 17% and 65% depending on how chronic pain is defined and how long patients are followed. Other surgeries with elevated chronic pain risk include limb amputation (phantom limb pain), mastectomy, and hernia repair. The common thread is direct nerve involvement during the procedure. Surgeries that are intensely painful but don’t involve significant nerve damage, like knee replacement, tend to have lower rates of chronic pain once rehabilitation is complete.