A kidney is removed through a procedure called nephrectomy, which can be performed as open surgery through an incision in the side or abdomen, or through small keyhole incisions using laparoscopic or robotic instruments. The choice between these approaches depends on why the kidney needs to come out, how large the mass is, and whether the surgeon can save part of the organ. Modern kidney surgery has shifted heavily toward minimally invasive techniques since the first laparoscopic nephrectomy was performed in 1990, and toward removing only the diseased portion of the kidney whenever possible.
Why a Kidney Needs To Come Out
The most common reason for removing a kidney or part of one is a kidney tumor, particularly renal cell carcinoma. Other reasons include donation to someone who needs a transplant, a kidney that has been destroyed by infection or obstruction and no longer functions, and in children, conditions like severe reflux or a kidney that never developed properly. The diagnosis and size of the problem largely determine whether the whole kidney is removed (radical nephrectomy) or just the affected portion (partial nephrectomy).
Partial Versus Radical Nephrectomy
If a tumor is confined to one area of the kidney and is not too large, surgeons strongly prefer to remove only the tumor and a small margin of healthy tissue around it, leaving the rest of the kidney intact. This is partial nephrectomy, sometimes called nephron-sparing surgery. Radical nephrectomy removes the entire kidney and, depending on the situation, surrounding fat and sometimes the adrenal gland sitting on top of it. A systematic review and meta-analysis of over 11,000 patients found that cancer outcomes between the two procedures were similar for tumors up to about seven centimeters, but partial nephrectomy carried a higher rate of postoperative complications and greater blood loss during surgery.
So why bother saving part of the kidney if it means a trickier operation? Because keeping healthy kidney tissue matters for long-term health. Research comparing the two approaches in patients with smaller tumors has found similar rates of cancer progression, but better preservation of kidney function with the partial approach.
A Cochrane review confirmed that for localized kidney masses, partial nephrectomy appears to result in little to no difference in cancer-specific survival or time to recurrence compared with radical nephrectomy.
Preoperative Imaging and Surgical Planning
Before any kidney surgery, the surgical team needs a detailed map of the anatomy. Kidneys have complex blood supply, and no two people are exactly alike. The main renal artery typically divides into front and back branches, which then split into roughly five smaller arteries that each feed a specific zone of the kidney. Variations in this vascular layout are common, so imaging is essential.
The standard workup includes contrast-enhanced CT or MRI scanning, which shows the tumor’s size and location, plus how the blood vessels are arranged. Surgeons use anatomy-based scoring systems derived from these scans to grade the complexity of a partial nephrectomy and predict the risk of complications.
Some centers now go a step further, building patient-specific three-dimensional models from CT data. These models let the surgeon visualize how the tumor relates to blood vessels and the collecting system before making the first incision.
Open Surgery
In open nephrectomy, the surgeon makes an incision in the flank, the side of the body between the lower ribs and the hip. A common approach uses an incision just above or below the 11th or 12th rib. One series using a mini-flank incision above the 11th rib reported a median operative time of about three hours, blood loss around 400 milliliters, and a median hospital stay of five days. Late complications in that group were uncommon, though about four percent developed a flank bulge or hernia at the incision site.
Open surgery was the only option for decades, and it remains necessary for very large tumors, tumors that have grown into major blood vessels, or cases where laparoscopic access is not feasible. Flank incisions do cause significant early pain. A study of kidney donors who had open flank incisions found that roughly seven in ten described severe pain on the first day after surgery, though the vast majority had stopped needing pain medication within a month.
Laparoscopic and Robotic Approaches
The introduction of laparoscopic nephrectomy in 1990 marked a turning point. Instead of a large incision, the surgeon works through several small ports, each about five to twelve millimeters across, using a camera and long instruments. The kidney or tumor is freed from its attachments, the blood vessels are sealed and cut, and the specimen is removed through a slightly larger incision or a small hand-assist port.
There are two main routes for laparoscopic access. The transperitoneal approach goes through the abdominal cavity, giving a wide working space and familiar landmarks. The retroperitoneal approach enters from the back, staying behind the lining of the abdominal cavity. This route provides direct access to the kidney’s blood vessels and avoids disturbing the bowel, but the working space is tighter, port placement is more constrained, and there is a slightly higher risk of pneumothorax because of the proximity to the lung base.
Robotic-assisted surgery, most commonly using the da Vinci platform, has become the dominant approach for partial nephrectomy at many large centers. The surgeon sits at a console and controls wristed instruments with enhanced dexterity and a magnified three-dimensional view. The robot does not operate autonomously; it translates the surgeon’s hand movements into precise instrument movements. Robotic assistance is especially helpful during partial nephrectomy, where the surgeon must cut out the tumor and then quickly sew the remaining kidney tissue back together under time pressure.
What Happens During the Operation
Regardless of the approach, the basic steps of a nephrectomy follow a similar sequence. The surgeon first exposes the kidney by clearing away surrounding fat and tissue. The renal artery and vein are identified and isolated. In a radical nephrectomy, those vessels are permanently sealed using clips, staplers, or energy devices, then divided, and the entire kidney is freed from its attachments and removed.
In a partial nephrectomy, the process is more nuanced. After the kidney is mobilized and the blood vessels are isolated, the surgeon typically clamps the renal artery to temporarily stop blood flow to the kidney. This creates a bloodless field so the tumor can be precisely cut out. Once the tumor is excised with a margin of normal tissue, the surgeon repairs the open wound on the kidney, suturing closed any blood vessels or collecting-system entries, and then reconstructs the kidney surface. The clamp is then released to restore blood flow.
For donor nephrectomy, preserving the length of the renal vein is a priority so the transplant team has enough vessel to work with when sewing the kidney into the recipient. Techniques include placing a vascular clamp across the vena cava itself, allowing the surgeon to take the full length of the renal vein flush with the main vein.
When it comes to sealing the major vessels, a meta-analysis comparing clips and staplers in laparoscopic donor nephrectomy found that clips resulted in somewhat more blood loss and longer warm ischemia time than staplers, but the rates of device failure, severe bleeding, and death did not differ between the two. Clips were about $400 cheaper per patient.
Warm Ischemia and Protecting the Remaining Kidney
During partial nephrectomy, the time the kidney spends without blood flow, called warm ischemia time, is one of the most critical variables. Prolonged ischemia damages healthy tissue, so surgeons aim to keep this period short, generally under thirty minutes. Several strategies have been developed to minimize it.
“Early unclamping” means the surgeon removes the clamp after cutting out the tumor and performing only a quick initial repair, then finishes sewing the kidney back together while blood is flowing again. This technique has been shown to reduce warm ischemia time from roughly 22 minutes to about 17 minutes, though blood loss tends to be higher. Use of barbed suture material, which holds itself in place without knots, has also shaved minutes off clamping time.
Some surgeons pursue “zero-ischemia” techniques, clamping only the tiny arterial branch feeding the tumor zone rather than the main artery, so the rest of the kidney never loses blood supply. This requires detailed preoperative imaging to identify the correct branch. Off-clamp surgery, where no artery is clamped at all, is another option for smaller tumors. Compared to clamped surgery, off-clamp robotic partial nephrectomy preserves slightly more kidney function, though the clinical difference is small.
In some cases, surgeons use cold ischemia instead, flushing ice slush around or into the kidney to cool it and slow its metabolism during the clamped period. One report described delivering ice through a dedicated trocar during robotic surgery, allowing a 32-minute clamp time with kidney function returning to preoperative levels within two weeks.
Complications and Risks
Like any major surgery, nephrectomy carries risks. A study of over 550 patients undergoing radical nephrectomy found that about 19 percent experienced at least one early complication. Most of these were mild, such as minor infections or temporary blood-count drops that resolved without intervention. Serious complications requiring additional surgery or intensive care occurred in roughly two to three percent of patients. The strongest predictors of complications were older age and greater blood loss during the operation. Whether the surgeon used a transperitoneal or retroperitoneal route did not meaningfully change the complication rate.
For partial nephrectomy, the complication profile is somewhat different. Because the kidney is being cut into and repaired rather than simply removed, there is a risk of bleeding from the repair site, urine leakage from the collecting system, and arteriovenous fistula formation. A meta-analysis found that partial nephrectomy carried about 1.7 times the likelihood of postoperative complications compared to radical nephrectomy, which is the trade-off accepted in exchange for preserving kidney tissue.
Recovery and Enhanced Recovery Protocols
Hospital stays after kidney surgery have shortened considerably in recent years. A study tracking the impact of a standardized recovery pathway found that median length of stay dropped forty percent for open kidney surgery, from five days down to three, and from three days down to two for minimally invasive procedures, with no increase in major complications at 30 days.
Enhanced recovery after surgery (ERAS) protocols bundle together evidence-based practices across the entire surgical experience: minimizing fasting before surgery, using multimodal pain control to reduce opioid use, getting patients walking early, removing catheters sooner, and allowing solid food quickly after the operation. One study comparing outcomes before and after implementing such a protocol found that opioid use dropped dramatically, with median morphine equivalents falling from 4 milligrams to zero and oxycodone use dropping from over 50 milligrams to under 10. Direct costs per patient fell by about 25 percent, from roughly $13,000 to $9,800, with no increase in readmissions.
A randomized trial of an ERAS protocol tailored specifically for robotic partial nephrectomy found that the ERAS group had significantly fewer complications overall, with complication rates of about 14 percent versus 39 percent in the standard-care group. Patients in the ERAS group were walking about four hours sooner and went home days earlier.
How the Remaining Kidney Adapts
After one kidney is removed, the remaining kidney undergoes a process called compensatory renal hypertrophy. It physically enlarges and increases its filtering capacity to take over the work of the missing organ. This happens through two mechanisms: the remaining kidney’s nephrons (its individual filtering units) each start working harder, and the kidney tissue actually grows. Blood flow and filtration rates in each nephron rise proportionally to compensate for the lost organ.
This adaptation is robust but not complete. The remaining kidney does not fully double its output to match what two kidneys were doing. Research suggests kidney function typically stabilizes within about three months of surgery. In one study, about 44 percent of patients who had a radical nephrectomy experienced a sharp drop in kidney function immediately after surgery, and about half had their kidney disease stage worsen over time.
Whether the reduced kidney function that follows nephrectomy carries the same health risks as kidney disease from other causes, like diabetes or high blood pressure, is debated. Some researchers argue that surgical loss of kidney mass is fundamentally different from medical kidney disease, because the remaining tissue is healthy. Others counter that low filtration rate carries cardiovascular and mortality risk regardless of the cause.
Risk Factors for Long-Term Kidney Problems
A meta-analysis pooling data from over 13,000 patients identified several factors that increase the chance of developing chronic kidney disease after losing a kidney. Each additional year of age raised the risk by about five percent. Diabetes, male sex, and lower baseline kidney function before surgery all pushed the odds higher. The single biggest modifiable factor was the type of surgery: compared to partial nephrectomy, radical nephrectomy increased the risk of chronic kidney disease nearly fourfold.
This is a major reason surgeons favor partial nephrectomy whenever the tumor’s size and location allow it. For people who end up with a single kidney after surgery, guidelines suggest keeping protein intake moderate (not exceeding about one gram per kilogram of body weight per day), limiting sodium, maintaining a healthy body weight, and managing conditions like high blood pressure and diabetes closely.
Kidney Surgery in Children
In pediatric patients, the reasons for nephrectomy are often different from adults. Children rarely have renal cell carcinoma; instead, they may need a nonfunctioning kidney removed because of severe vesicoureteral reflux, obstruction at the junction where the kidney meets the ureter, or a kidney that never developed properly. In many of these cases, it is not just the kidney but the abnormal, dilated ureter below it that causes recurring infections and needs to come out completely.
One center’s 20-year experience with laparoscopic nephrectomy in children covered 149 cases, all for nonfunctioning kidneys due to benign conditions like reflux, obstruction, or multicystic dysplastic kidney. The laparoscopic approach in children follows the same principles as in adults but with scaled-down instruments and port sizes.
Fluorescence-Guided Surgery
One of the more striking advances in kidney surgery involves injecting a dye called indocyanine green (ICG) into the bloodstream during robotic partial nephrectomy. Under near-infrared light, healthy kidney tissue that receives blood flow glows bright green, while the tumor typically stays dark because its blood supply is different. This fluorescence map helps the surgeon see the tumor boundaries more clearly and, when doing selective clamping, confirm exactly which arterial branch feeds the tumor zone.
A study of 37 robotic partial nephrectomies performed with ICG navigation reported a mean warm ischemia time of just 14 minutes and successful tumor-specific vessel clamping in about two-thirds of cases. The technology also helps the surgeon verify that the remaining kidney tissue is well-perfused after the tumor has been removed and the repair is complete, providing real-time feedback that was not available with conventional laparoscopic cameras.