Segmental resection, also known as segmentectomy, is a surgical procedure that removes a specific, anatomically defined portion of an organ or gland, often including a tumor and a margin of surrounding normal tissue, while aiming to preserve the function of the remaining healthy tissue.^[1] This organ-sparing approach contrasts with more extensive resections like lobectomy or total organ removal, making it suitable for localized pathologies such as early-stage cancers, benign tumors, infections, or inflammatory conditions.^[2] It is performed across multiple specialties, with common applications in the lungs, liver, colon, breast, and kidney, guided by precise anatomical divisions to minimize morbidity and support postoperative recovery.^[3][4] In pulmonary surgery, segmental resection targets one or more bronchopulmonary segments—self-contained units supplied by a segmental bronchus, artery, and vein—primarily for treating stage I non-small cell lung cancer in patients with limited disease or poor tolerance for larger resections.^[2] Introduced in the 1970s by surgeon Robert Jensik as a conservative alternative to lobectomy, it preserves greater lung volume, reduces postoperative respiratory complications, and improves quality of life, though it requires adequate surgical margins (at least 2 cm) and lymph node evaluation to mitigate higher recurrence risks compared to more radical procedures.^[2] Techniques have evolved from open thoracotomy to minimally invasive methods like video-assisted thoracoscopic surgery (VATS) or robotic assistance, shortening hospital stays and enhancing precision.^[2] For the liver, segmental resection follows the Couinaud classification, which divides the organ into eight functional segments based on vascular and biliary anatomy, allowing targeted removal for hepatocellular carcinoma, metastases, or benign lesions while maintaining regenerative capacity.^[5][4] This approach, often laparoscopic, is preferred for peripheral tumors in patients with adequate liver reserve, offering lower blood loss and faster recovery than major hepatectomies, though it demands advanced imaging for planning.^[4] In colorectal surgery, segmental resection excises a diseased section of the colon or rectum—such as in adenocarcinoma, diverticulitis, or Crohn's disease—followed by anastomosis of the healthy ends to restore continuity.^[3][6] It is the standard for localized colorectal cancers, balancing oncologic clearance with preservation of bowel function, and may involve laparoscopic or open techniques depending on tumor location and patient factors.^[6] Breast segmental resection, synonymous with segmental mastectomy or wide local excision, removes the tumor and a larger rim of normal breast tissue for early-stage breast cancer, serving as a breast-conserving alternative to total mastectomy when combined with radiation therapy.^[7] This procedure, often guided by imaging, achieves equivalent survival outcomes to mastectomy for suitable candidates while maintaining cosmetic integrity.^[7] In the kidney and urinary tract, partial nephrectomy (including segmental approaches) is used for localized renal cell carcinoma to preserve nephrons and renal function, particularly in patients with solitary kidneys or bilateral disease.^[8] For transitional cell cancers of the renal pelvis and ureter, segmental resection removes the affected portion.^[9] Partial nephrectomy techniques, including segmental approaches, are now standard for small tumors, with robotic assistance improving outcomes.^[8] Overall, segmental resection exemplifies precision surgery, leveraging advances in imaging, minimally invasive tools, and anatomical knowledge to optimize therapeutic efficacy and patient-centered care across diverse organ systems.^[2][3]

Definition and Classification

Definition

Segmental resection is a surgical procedure that involves the excision of a specific, anatomically defined segment of an organ or gland, functioning as a subtype of partial resection to preserve the remaining functional tissue.^[10] Commonly referred to as segmentectomy or partial organ resection, this approach targets discrete portions of the organ while minimizing disruption to overall structure and function.^[11] The procedure is grounded in the organ's segmental anatomy, focusing on independent vascular or functional units that can be isolated and removed without compromising the viability of adjacent areas. In the lungs, for instance, it involves the bronchopulmonary segments, which are the largest functional subdivisions of the lung lobes, each receiving dedicated arterial, venous, and bronchial supplies.^[2][12] Similarly, in the liver, segmental resection adheres to the Couinaud classification, which delineates eight functionally independent segments based on their unique portal vein, hepatic vein, and biliary drainage patterns.^[13][14] In contrast to total resection, which entails complete removal of the organ and often results in permanent loss of its function, segmental resection prioritizes organ preservation to sustain physiological roles, making it particularly suitable for managing localized diseases while avoiding the need for lifelong replacement therapies or compensatory mechanisms.^[6][2]

Comparison with Other Resection Types

Segmental resection occupies a middle ground among resection types, offering anatomical precision while preserving more organ function than more extensive procedures. In pulmonary surgery, it contrasts with wedge resection, which involves the non-anatomical removal of a small, wedge-shaped portion of lung tissue typically for peripheral, early-stage lesions less than 2 cm in diameter, providing less oncologic control due to potential incomplete margins but minimizing surgical trauma.^[15] In comparison, lobectomy entails the complete excision of an entire lung lobe, making it more radical and suitable for larger or centrally located tumors where wider margins are needed to reduce recurrence risk.^[16] Similarly, in colorectal surgery, segmental resection removes a discrete portion of the colon, differing from hemicolectomy, which excises half the colon (right or left) for more extensive regional disease, thereby achieving greater lymph node clearance but at the cost of broader functional loss.^[6] More radical options like pneumonectomy or total colectomy involve complete organ or near-complete removal, reserved for diffuse or advanced disease where preservation is untenable, such as centrally invasive lung tumors or widespread colonic involvement.^[17] Pneumonectomy, for instance, eliminates an entire lung, severely impacting pulmonary reserve and quality of life, whereas total colectomy mandates alternative waste management like ileostomy, contrasting sharply with segmental resection's goal of maintaining physiological integrity.^[6] These total resections prioritize oncologic radicality over function, often leading to higher morbidity rates compared to segmental approaches.^[17] The primary advantage of segmental resection lies in its balance, reducing postoperative functional deficits; for example, in early-stage non-small cell lung cancer, segmentectomy preserves better pulmonary reserve than lobectomy while demonstrating equivalent 5-year overall survival rates of more than 90% for both, with fewer serious complications.^[16] It also outperforms wedge resection in survival outcomes, with 5-year rates of 83% compared to 75% for wedge procedures in comparable patients, due to its anatomical basis ensuring thorough segmental lymphovascular clearance.^[15] Segmental resection is thus preferred for early-stage malignancies or benign conditions where clear margins can be obtained without excessive tissue sacrifice, such as small peripheral lung nodules or localized colonic polyps, allowing patients to retain sufficient organ capacity for daily activities and future interventions if needed.^[6]

Indications

Pulmonary Segmental Resection

Pulmonary segmental resection, also known as segmentectomy, is a lung-sparing surgical procedure that removes one or more bronchopulmonary segments while preserving the remaining lung tissue, primarily indicated for early-stage non-small cell lung cancer (NSCLC) in patients with limited pulmonary reserve. This approach is particularly suitable for peripheral tumors measuring 2 cm or less in maximum diameter, aiming for a resection margin of at least the tumor diameter or 2 cm, as per guidelines, to achieve oncologic clearance.^[18][19][20] The procedure targets the 18 to 19 bronchopulmonary segments of the lungs—10 in the right lung and 8 to 9 in the left—most commonly involving segments in the upper or lower lobes to minimize functional loss.^[21] Beyond NSCLC, segmental resection addresses other conditions such as benign tumors, bronchiectasis, infectious diseases like tuberculosis, and limited metastatic disease, where localized resection suffices without compromising overall lung function.^[2][22][23] Patient selection emphasizes preoperative pulmonary function tests (PFTs), with predicted postoperative forced expiratory volume in one second (ppoFEV1) greater than 30% to 40% of predicted values indicating operability, though values between 30% and 60% often classify patients as moderate to high risk, favoring segmentectomy over more extensive resections like lobectomy.^[24] The oncologic rationale for pulmonary segmental resection in small, early-stage tumors rests on its equivalence to lobectomy in long-term outcomes, as demonstrated by the CALGB 140503 trial, which reported 5-year overall survival rates of approximately 80% for stage IA NSCLC with tumors ≤2 cm, comparable between segmentectomy and lobectomy groups (80.3% vs. 78.9%).^[18] This preservation of pulmonary function—evidenced by less decline in FEV1 post-segmentectomy—supports its use in patients with compromised reserve, offering similar disease-free survival (around 64% at 5 years) and recurrence rates without increased locoregional risk.^[18]

Colorectal Segmental Resection

Colorectal segmental resection involves the removal of a specific portion of the colon or rectum affected by disease, followed by primary anastomosis to restore bowel continuity, and is primarily indicated for localized colorectal cancer in stages I and II, where the tumor is confined to the bowel wall or has limited regional spread without distant metastasis.^[25] It is also employed for complicated diverticulitis, such as cases involving perforation, abscess formation, or fistula, particularly when medical management fails or recurrent episodes occur.^[26] In inflammatory bowel disease, particularly Crohn's disease, segmental resection addresses strictures causing obstruction in the colon, aiming to relieve symptoms while preserving as much bowel length as possible.^[27] Patient selection for colorectal segmental resection emphasizes precise preoperative staging to ensure suitability, utilizing colonoscopy for direct visualization and biopsy of lesions, combined with computed tomography (CT) scans to assess tumor depth, lymph node involvement, and the absence of widespread metastasis.^[25] Ideal candidates include those with tumors in accessible segments like the sigmoid or descending colon, where complete resection with adequate margins of at least 5 cm proximally and distally for colon cancers, and appropriate distal margins (typically 2 cm or more) for rectal cancers to preserve sphincter function where possible, is feasible.^[28] Contraindications include advanced disease with peritoneal carcinomatosis or extensive comorbidities that elevate surgical risk, prioritizing elective procedures over emergent ones.^[25] The surgical approach typically entails laparoscopic or open excision of the diseased colonic segment—for instance, sigmoid colectomy for diverticulitis—along with mesenteric lymph node dissection in oncologic cases to achieve oncologic clearance.^[29] Primary end-to-end anastomosis is performed using stapling devices or hand-sewn techniques to reconnect healthy bowel ends, minimizing the need for temporary ostomies in elective settings.^[25] In emergency scenarios, such as perforated diverticulitis with peritonitis, a variant like Hartmann's procedure may be used, involving resection and creation of an end colostomy, with delayed reconstruction if needed, though elective segmental resection remains the focus for optimized recovery.^[26] Oncologic outcomes for stage I-II colorectal cancer treated with segmental resection demonstrate high efficacy, with 5-year overall survival rates exceeding 85%, reaching approximately 97% for stage I and 87% for stage II disease.^[30] This procedure reduces local recurrence risk compared to local excision alone, where rates can reach 18% for T1 and 37% for T2 lesions, due to more comprehensive margin and nodal assessment.^[25] For non-malignant indications like diverticulitis and Crohn's strictures, segmental resection effectively prevents recurrence in over 90% of uncomplicated cases post-resection, with low complication rates when performed electively.^[26][27]

Applications in Other Organs

Segmental resection of the liver, guided by the Couinaud classification of hepatic segments, is employed for treating hepatocellular carcinoma (HCC) or liver metastases, where the goal is to remove the tumor-bearing segment while preserving sufficient remnant liver volume, typically at least 30% of the total liver volume in non-cirrhotic patients to avoid postoperative liver failure.^[31] For instance, segmentectomy of segments VII and VIII may be performed for tumors in the right posterior-superior liver, enabling anatomical resection that follows the portal vein branches and minimizes blood loss.^[32] This approach is particularly valuable in cirrhotic livers, where extensive resections risk decompensation, and studies have shown it achieves comparable oncologic outcomes to lobectomy with better functional preservation.^[33] In breast cancer management, segmental resection serves as a breast-conserving technique, encompassing procedures like lumpectomy or quadrantectomy for early-stage disease, wherein the tumor and a margin of surrounding tissue are excised to achieve clear margins while maintaining breast aesthetics and function.^[34] This method is indicated for tumors typically less than 5 cm in diameter with favorable location, allowing for adjuvant radiation to control local recurrence rates equivalent to mastectomy.^[35] Oncoplastic techniques may integrate with segmental resection to reshape the breast, reducing deformity and improving cosmetic outcomes in up to 80% of cases.^[36] For the duodenum and small bowel, segmental resection is applied to localized benign or malignant neoplasms, such as gastrointestinal stromal tumors (GISTs) or adenocarcinomas, involving removal of the affected segment followed by primary anastomosis to restore continuity.^[37] Indications include tumors confined to a short segment, often less than 5 cm, particularly in the third or fourth portion of the duodenum where pancreaticoduodenectomy can be avoided to limit morbidity.^[38] This organ-sparing strategy has demonstrated five-year survival rates exceeding 70% for low-risk GISTs when margins are clear.^[39] Renal segmental resection, often termed partial nephrectomy, targets small renal cell carcinomas (typically <4 cm) in polar segments of the kidney, excising the tumor while preserving nephrons to maintain renal function and avoid dialysis in patients with a solitary kidney or comorbidities.^[40] This procedure is preferred for T1a tumors, with techniques like polar nephrectomy allowing en bloc removal of upper or lower pole lesions and achieving oncologic efficacy comparable to radical nephrectomy, including 95% five-year cancer-specific survival.^[41] Across these organs, the rationale for segmental resection emphasizes organ preservation to sustain vital functions—such as hepatic detoxification, renal filtration, gastrointestinal transit, and breast integrity—while achieving oncologic control, thereby improving quality of life compared to more radical alternatives.^[42]

Surgical Techniques

Preoperative Evaluation

Preoperative evaluation for segmental resection involves a comprehensive assessment to determine surgical candidacy, optimize patient condition, and plan the procedure to achieve oncologic goals such as complete tumor removal with negative margins. This process is tailored to the organ involved, incorporating imaging for precise localization and staging, functional testing to predict postoperative reserve, and optimization of comorbidities. Multidisciplinary review ensures feasibility, particularly in oncologic cases where segmental resection may serve as a lung-sparing or parenchyma-preserving alternative to more extensive surgery.^[2] Imaging plays a central role in tumor localization, staging, and mapping segmental anatomy. For pulmonary segmental resection, contrast-enhanced CT of the chest and abdomen is standard for initial staging, often supplemented by PET-CT to detect metastases and refine nodal assessment. In liver cases, multiphase CT or MRI delineates vascular and segmental anatomy, with 3D reconstruction increasingly used to simulate resection planes and estimate remnant liver volume. For colorectal segmental resection, CT of the chest, abdomen, and pelvis identifies local extent and distant disease, while colonoscopy confirms the lesion's location. For breast segmental resection, mammography, ultrasound, or MRI guides tumor localization, often with wire placement. In kidney cases, CT or MRI assesses tumor size, location, and renal anatomy to plan partial nephrectomy. These modalities guide the decision for segmental approaches by visualizing tumor margins and adjacent structures.^{[2][43][44][45][46]} Functional tests assess organ reserve to predict postoperative function and risk. In pulmonary resections, pulmonary function tests (PFTs) measure baseline forced expiratory volume in 1 second (FEV1), with predicted postoperative FEV1 calculated as:

$$\text{ppoFEV1} = \text{preoperative FEV1} \times \left(1 - \frac{\text{segments removed}}{19}\right)$$

This anatomic method helps determine if ppoFEV1 exceeds 30-40% predicted, indicating low risk; values below may require ventilation-perfusion scanning or exercise testing. For liver resections, the Child-Pugh score evaluates synthetic function using bilirubin, albumin, prothrombin time, ascites, and encephalopathy, classifying patients as A (lowest risk, score 5-6) for safe resection up to major hepatectomy. In colorectal cases, basic labs like complete blood count and carcinoembryonic antigen (CEA) assess overall fitness, though specific segmental function testing is less emphasized. For breast, renal function and cardiac assessment are routine but less organ-specific. In kidney resections, estimated glomerular filtration rate (eGFR) predicts postoperative renal function, with split renal function via nuclear scan if needed for solitary kidney cases.^[47][43] Patient optimization addresses modifiable risks to reduce complications. Smoking cessation is critical for lung resections, as current smoking increases hospital mortality risk approximately 3.5-fold compared to never-smokers. Preoperative cessation reduces this risk over time, with optimal benefits after at least 4-8 weeks of abstinence if possible, though patients should quit as soon as diagnosed to allow any mitigation. Nutritional assessment, using tools like the Mini Nutritional Assessment, identifies malnutrition in up to 40% of surgical candidates, prompting preoperative supplementation to improve wound healing and reduce infections. Comorbidity management includes cardiac evaluation via stress testing for those with risk factors, as perioperative cardiac events occur in 2-5% of thoracic cases. For breast and kidney, similar optimization applies, with emphasis on endocrine status or hypertension control.^[48][49][48] Multidisciplinary input, often through tumor board review, confirms segmental resection's suitability in oncologic settings by weighing feasibility against alternatives like lobectomy or total colectomy, integrating pathology, radiology, and oncology perspectives to prioritize R0 resection (microscopically negative margins). This is particularly relevant for breast and kidney cases to assess conservation feasibility.^[50] Informed consent discusses procedure-specific risks (e.g., 1-2% mortality for lung segmentectomy), alternatives, and goals like achieving R0 margins to minimize recurrence, with margin width ideally ≥2 cm but adjusted for anatomy. Similar discussions cover cosmetic outcomes for breast or renal function preservation.^[51]

Intraoperative Methods

Intraoperative methods for segmental resection vary by organ but generally involve precise access, segment demarcation, vascular management, parenchymal division, and reconstruction where applicable, with an emphasis on minimizing blood loss and preserving function. For pulmonary segmental resection, access is achieved via thoracotomy for open procedures or video-assisted thoracoscopic surgery (VATS) for minimally invasive approaches, which utilize small incisions and thoracoscopic visualization to reduce postoperative pain and recovery time. In colorectal cases, laparotomy provides direct open access, while laparoscopy employs trocars for insufflation and endoscopic tools, facilitating mobilization and resection with lower morbidity in elective settings. Hepatic segmental resections similarly leverage laparotomy or laparoscopy, often incorporating intraoperative ultrasound for real-time guidance during parenchymal transection. For breast, access is via incision over the tumor site, often with wire guidance; for kidney, open, laparoscopic, or robotic flank/retroperitoneal access is used.^{[2][52][53][45][46]} Segment identification is critical to ensure oncologic margins and functional preservation, particularly in lung procedures where the intersegmental plane is delineated using the inflation-deflation method: after hilar dissection, the lung is reinflated selectively to create a visible boundary between inflated target segments and deflated adjacent ones, aiding precise cutting along natural planes. Intraoperative ultrasound or electromagnetic navigation systems further refine boundaries in complex hepatic or colorectal resections by mapping vascular and segmental anatomy in real time. In breast, specimen radiography confirms margins; in kidney, ultrasound or indocyanine green (ICG) fluorescence aids segmental demarcation.^[54][55][46] Resection proceeds with vascular control, involving ligation or stapling of segmental arteries and veins to isolate the target, followed by parenchymal transection using endoscopic linear staplers in lung cases for efficient division with minimal hemorrhage, or the cavitron ultrasonic surgical aspirator (CUSA) in liver resections to fragment and aspirate tissue while sparing vessels. In breast, electrocautery or ultrasonic scalpel removes tissue; in kidney, hilar clamping (warm/cold ischemia) precedes excision with parenchymal sutures. Lymph node sampling, especially mediastinal or mesenteric stations, is routinely integrated to assess staging, particularly in non-small cell lung cancer (NSCLC); sentinel node biopsy is standard for breast, while hilar/lymphatic dissection applies to kidney.^[56][2][45] Reconstruction differs by site: in colorectal segmental resection, primary end-to-end anastomosis is performed using staplers or sutures after bowel mobilization and vascular division, often extracorporeally in laparoscopic approaches to ensure tension-free alignment. Pulmonary resections require no formal anastomosis but address potential air leaks with buttressing materials or sealants, such as polyethylene glycol-based products applied to staple lines, which reduce prolonged air leak incidence by sealing alveolar disruptions. In breast, the defect is closed primarily or with oncoplastic techniques; in kidney, renorrhaphy with slides or bolsters reconstructs the parenchyma. Robotic-assisted variants enhance precision in minimally invasive thoracic or abdominal procedures, with feasibility exceeding 90% for complex NSCLC segmentectomies due to three-dimensional visualization and articulated instruments that facilitate hilar dissection in tight spaces; similar benefits apply to kidney partial nephrectomies. Elective cases typically last 2-4 hours with blood loss under 500 mL, influenced by access method and segment complexity, as evidenced by median times of 180 minutes and 100 mL loss in laparoscopic colorectal resections. Breast procedures are shorter (1-2 hours), kidney 2-3 hours.^{[57][58][59][60]}

Postoperative Management

Following segmental resection, patients undergo structured postoperative management to optimize recovery, prevent complications, and promote organ-specific function restoration. This includes vigilant monitoring, multimodal pain control, and tailored supportive interventions, with protocols often guided by enhanced recovery after surgery (ERAS) principles where applicable. Breast and kidney follow similar principles, with focus on wound care and function monitoring.^[61][62] In pulmonary segmental resection, high-risk patients—such as those with comorbidities or limited pulmonary reserve—may require initial monitoring in the intensive care unit (ICU) overnight to assess for immediate issues like respiratory instability. Chest tubes are routinely placed and monitored every 8 hours for air leakage and fluid output, typically remaining in place for 2-5 days until output is minimal and no air leak persists, after which they are removed prior to discharge. Pain management employs patient-controlled analgesia (PCA) or thoracic epidural catheters for the initial 2-3 days, followed by a transition to oral narcotics and nonsteroidal anti-inflammatory drugs (NSAIDs) once chest tubes are out; this multimodal approach minimizes opioid use while ensuring comfort. Respiratory care emphasizes incentive spirometry, deep breathing exercises, and early mobilization within 24 hours to prevent atelectasis and pneumonia, often supplemented by chest physiotherapy and supplemental oxygen if needed due to underlying smoking history or reduced lung function. For kidney, drain monitoring for urine leak and serial creatinine checks are key; breast emphasizes arm mobility to prevent lymphedema.^[61][2][63] For colorectal segmental resection, monitoring focuses on vital signs and clinical status in a standard surgical ward unless complications arise, with prophylactic antibiotics administered preoperatively and discontinued within 24 hours postoperatively to prevent infections. Pain control follows an opioid-sparing ERAS protocol, incorporating thoracic epidural analgesia for open procedures (if an acute pain team is available), transversus abdominis plane (TAP) blocks, intravenous acetaminophen, and judicious NSAIDs, avoiding routine long-term opioids. Nutritional support prioritizes early enteral or oral feeding within 24 hours to reduce ileus risk, starting with clear liquids and advancing to a regular diet as tolerated, potentially aided by chewing gum to stimulate bowel motility; wound care involves surgical site infection (SSI) prevention bundles, such as wound protectors and glove changes before closure, with standard dressings and no routine drains unless indicated. Respiratory care, while less emphasized than in thoracic cases, includes incentive spirometry and mobilization within 24 hours to mitigate pulmonary complications. For breast, early shoulder exercises and radiation planning; for kidney, early ambulation to prevent thrombosis.^[62][64] Follow-up imaging begins with a routine chest X-ray on postoperative day 1 for pulmonary cases to evaluate lung re-expansion and tube placement, with additional X-rays before chest tube removal; for oncologic surveillance in both pulmonary and colorectal resections, a computed tomography (CT) scan is typically performed around 1 month postoperatively to assess for residual disease or early recurrence, though routine imaging is otherwise guided by clinical suspicion. For breast, mammogram at 6-12 months; for kidney, ultrasound or CT to monitor function and recurrence. Patients are monitored closely for potential complications such as air leaks, anastomotic issues, or infections, with prompt intervention as needed.^[61][65][62] Discharge criteria generally include stable vital signs, adequate pain control on oral medications, independent mobility, and tolerance of oral intake (semisolids for pulmonary cases, regular diet for colorectal), typically achieved within 3-7 days postoperatively depending on surgical approach (e.g., shorter for video-assisted thoracoscopic surgery or laparoscopic procedures) and absence of ongoing issues like air leaks or ileus. Breast discharge often same-day or 1-2 days; kidney 2-4 days.^[61][62]

Complications and Risks

Intraoperative Complications

Intraoperative complications during segmental resection encompass immediate surgical risks that can arise from vascular, parenchymal, or technical challenges, varying by organ and approach. In pulmonary segmentectomy, bleeding from vascular injury, such as to the pulmonary artery or segmental veins, occurs in approximately 1-3% of cases, often necessitating immediate clamping, suturing, or conversion to thoracotomy for control.^[66][67] Air embolism, a rare but potentially life-threatening event in thoracic procedures, has been reported during segmentectomy due to venous disruption, with management involving prompt head-down positioning to trap air in the right ventricle and supportive ventilation.^[68] Pneumothorax, while more common postoperatively, can manifest intraoperatively from parenchymal disruption and is largely prevented through the use of double-lumen endotracheal intubation to achieve lung isolation and controlled collapse.^[69] Conversion from minimally invasive techniques like video-assisted thoracoscopic surgery (VATS) to open thoracotomy is an intraoperative event in pulmonary segmental resection, occurring in approximately 1% of cases in large databases, though rates up to 10% have been reported in earlier studies primarily due to adhesions, unfavorable anatomy, or uncontrolled bleeding that hinders visualization or dissection.^[70][71] In colorectal segmental resection, such as colectomy, intraoperative bleeding risks are mitigated by intracorporeal anastomosis techniques, which reduce blood loss compared to extracorporeal methods, though overall rates remain low without significant differences between open and laparoscopic approaches.^[72] Anastomotic issues, including tension or ischemia at the resection margins, are addressed intraoperatively through mobilization of the splenic flexure to relieve strain, careful assessment of bowel perfusion via visual inspection or adjunctive tools like indocyanine green fluorescence, and reinforcement with sutures or staplers to ensure viability and patency.^[73][74] In hepatic segmental resection, meticulous preoperative imaging and intraoperative monitoring, such as ultrasound guidance, help minimize risks by anticipating anatomical variations.^[75]

Postoperative Complications

Postoperative complications following segmental resection vary by organ and procedure but occur in approximately 20-30% of elective colorectal cases, with lower rates (e.g., 10-20%) reported for pulmonary and hepatic procedures; overall mortality rates are below 2% in well-selected patients.^[76] These issues typically arise in the immediate postoperative period on the ward or after discharge, emphasizing the need for vigilant monitoring, early intervention, and preventive strategies such as optimized perioperative antibiotics, enhanced recovery protocols, and chest physiotherapy for thoracic procedures. Common complications include infections, anastomotic disruptions, respiratory issues, and gastrointestinal dysmotility, each managed through a combination of conservative measures and targeted therapies to minimize morbidity. Infections represent a significant postoperative risk, with surgical site infections (SSI) affecting 5-10% of patients after colorectal segmental resections, often due to contamination from bowel contents.^[77] In pulmonary segmentectomies, pneumonia occurs in about 15% of cases, frequently linked to atelectasis, impaired mucociliary clearance, and mechanical ventilation effects.^[78] Prevention involves preoperative optimization of nutritional status, prophylactic antibiotics, and meticulous wound care; treatment typically includes broad-spectrum intravenous antibiotics tailored by culture results, alongside incision and drainage for localized collections or abscesses.^[79] Anastomotic leaks after colorectal segmental resections occur in 3-7% of cases, presenting with symptoms such as fever, abdominal pain, and peritonitis due to fecal spillage into the peritoneal cavity.^[80] Risk factors include technical anastomotic tension, poor blood supply, and patient comorbidities like malnutrition. Management prioritizes early detection via clinical signs, imaging (e.g., CT with contrast), and biomarkers like C-reactive protein; stable patients often undergo conservative therapy with bowel rest, total parenteral nutrition, antibiotics, and percutaneous drainage, while unstable cases with peritonitis require urgent reoperation for repair, diversion, or resection.^[81] In hepatic segmental resection, bile leakage occurs in 1-9% of cases, influenced by the extent of resection and operative duration exceeding 384 minutes, and is managed by placement of abdominal drains for decompression alongside biliary exploration if needed.^[82] Prolonged air leak, a form of respiratory failure after pulmonary segmental resection, affects around 10% of patients and manifests as persistent subcutaneous emphysema or pneumothorax due to incomplete parenchymal sealing.^[83] This complication prolongs chest tube duration and hospital stay, with prevention aided by intraoperative sealants and fissureless techniques. Resolution is achieved through chest tube adjustments, such as switching to water seal or low-pressure suction, alongside supportive measures like autologous blood pleurodesis or chemical agents in refractory cases; most resolve within 7-10 days without further intervention.^[84] Postoperative ileus or bowel obstruction complicates up to 20% of bowel resections, characterized by delayed gastric emptying, nausea, and abdominal distension from neurogenic and inflammatory disruptions in motility.^[85] Preventive strategies include multimodal analgesia to minimize opioid use, early ambulation, and prokinetic agents like gum chewing. Treatment focuses on conservative management with nasogastric tube decompression for decompression, intravenous fluid resuscitation to correct electrolyte imbalances, and bowel rest until flatus returns, avoiding unnecessary surgery unless mechanical obstruction is confirmed.^[79] In breast segmental resection (lumpectomy), common postoperative complications include seroma (5-10%), infection (1-2%), and fat necrosis, managed conservatively or with drainage. In renal partial nephrectomy, urine leak occurs in 2-5% and acute kidney injury in 5-10%, often requiring stenting or supportive care to preserve function.^[7][46]

Outcomes and Prognosis

Survival and Recurrence Rates

In non-small cell lung cancer (NSCLC), particularly for early-stage peripheral tumors (stage IA), segmental resection achieves 5-year relapse-free survival rates of approximately 88%, comparable to lobectomy (87.9%), as demonstrated in the JCOG0802/WJOG4607L randomized trial involving patients with tumors ≤2 cm.^[86] Overall 5-year survival rates range from 85% to 95% in selected stage IA cases, with overall recurrence rates of 10-20%; however, meta-analyses indicate a higher local recurrence risk with segmentectomy compared to lobectomy, though rates vary across studies and distant recurrences remain similar.^[87] For stage II colorectal cancer treated with segmental resection, 5-year overall survival rates typically range from 80% to 90%, particularly in low-risk cases with favorable tumor biology and complete resection.^[88] Recurrence rates are generally low at less than 10% for local events when adequate margins (≥5 cm proximally/distally) and sufficient lymph node harvest (≥12 nodes) are achieved, contributing to effective disease control.^[89][90] In hepatocellular carcinoma (HCC), segmental resection yields 5-year overall survival rates of 50-70% for early-stage disease meeting Milan criteria, though outcomes decline to 30-50% in the presence of underlying cirrhosis due to impaired liver function and higher recurrence risk.^[91][92] Segment-specific factors, such as involvement of central segments (e.g., IV or VIII), further influence prognosis by complicating complete resection and increasing postoperative liver insufficiency.^[93] For early-stage breast cancer, segmental mastectomy (lumpectomy) combined with radiation achieves 5-year overall survival rates exceeding 90%, equivalent to mastectomy, with local recurrence rates of 5-10% at 5 years when margins are clear.^[45] In localized renal cell carcinoma (stage I), partial nephrectomy (segmental resection) provides 5-year overall survival rates of approximately 95%, with low recurrence rates (5-10%) for tumors <4 cm, comparable to radical nephrectomy while preserving renal function.^[46] Key factors influencing survival and recurrence across these applications include tumor stage at diagnosis, achievement of negative margins (R0 resection), and integration of adjuvant therapies; for instance, chemotherapy following colorectal segmental resection improves outcomes in high-risk stage II cases by reducing systemic recurrence.^[25] In pulmonary cases, the JCOG0802 trial confirms segmentectomy's non-inferiority to lobectomy for oncologic control in eligible patients.^[86] Cirrhosis severity, assessed via Child-Pugh score, significantly impacts hepatic outcomes by elevating recurrence rates to 50-70% within 3 years post-resection.^[93]

Functional and Quality-of-Life Outcomes

Segmental resection in the pulmonary context preserves a greater proportion of lung function compared to more extensive procedures like lobectomy. Postoperative forced expiratory volume in one second (FEV1) is typically maintained at approximately 88% of baseline after segmentectomy, versus about 86% after lobectomy, with single-segment resections showing even less decline around 95%.^[94] This preservation correlates with reduced dyspnea and improved respiratory symptoms, as patients undergoing sublobar resections, including segmentectomy, report better scores in breathlessness, cough, and chest tightness on validated quality-of-life scales at 3 and 6 months postoperatively.^[95] In colorectal applications, segmental resection facilitates relatively rapid recovery of bowel function, with most patients regaining normal defecation patterns within 1 to 3 days post-surgery via minimally invasive approaches, and full functional restoration occurring over 4 to 6 weeks.^[96] The procedure is associated with a low rate of permanent stoma formation, typically under 5%, though temporary stomas occur in 2% to 17% of cases depending on resection site.^[97] Incontinence risk remains modest at 5% to 10%, primarily involving liquid stool or urgency, without significant long-term impact on overall bowel continence for most patients.^[97] For hepatic and renal segmental resections, organ function is generally well-maintained postoperatively. In partial nephrectomy, glomerular filtration rate (GFR) is preserved above 60 mL/min in the majority of cases, often exceeding 90% of baseline when ischemia time is limited to under 25 minutes, minimizing progression to chronic kidney disease.^[98] Similarly, after segmental hepatectomy, liver function recovers adequately, with remnant liver volume supporting normal synthetic capabilities. Fatigue emerges as the predominant quality-of-life concern in both, though it is typically mild and resolves within 6 to 12 weeks, with symptom scores indicating low severity.^[99] Across organ sites, segmental resection offers advantages in recovery metrics over total or more extensive resections, including shorter hospital stays of 3 to 5 days compared to 7 or more days for procedures like lobectomy or radical nephrectomy.^[94][96] Patients commonly return to work or normal activities within 4 to 8 weeks, facilitated by reduced tissue loss and fewer complications affecting mobility.^[100] Quality-of-life assessments using tools like the SF-36 and FACT scales demonstrate superior outcomes for segmental resection relative to more radical surgeries, with physical and social functioning domains showing stable or improved scores (often >80% of baseline) at 6 to 12 months, particularly in pulmonary and renal cases where function preservation is key.^[101][98] In liver resections, SF-12 scores reflect good overall recovery, with physical component summaries around 47 and minimal persistent deficits.^[99]

History and Development

Early Developments

The origins of segmental resection trace back to pulmonary surgery in the late 1930s, where it emerged as a conservative alternative to more extensive resections for localized benign diseases. In 1939, Edward D. Churchill and Ronald H. Belsey performed the first anatomical segmentectomy, a lingulectomy on the left upper lobe, to treat bronchiectasis in a patient with limited pulmonary reserve.^[102] This procedure targeted a specific bronchopulmonary segment while preserving adjacent lung tissue, marking a shift toward parenchyma-sparing techniques amid the era's high operative risks for thoracic interventions.^[103] In colorectal surgery, segmental resection built on early 20th-century foundations and gained traction in the mid-20th century for managing diverticulitis and other inflammatory conditions. Johann von Mikulicz-Radecki introduced partial colectomy techniques in 1903, advocating a two-stage approach involving exteriorization and resection to minimize contamination risks during anastomosis, initially for tumors but adaptable to diverticular disease.^[104] By the 1950s, advancements in antibiotics and anesthesia enabled more routine single-stage segmental resections for acute diverticulitis with peritonitis, as surgeons like Ryan and Welch reported improved outcomes with primary anastomosis following sigmoid resection, reducing the need for multi-stage procedures.^[104] The anatomical basis for precise segmental resections developed concurrently in the 1940s and 1950s through detailed mapping of organ segments. For the lungs, Chevalier L. Jackson and John F. Huber established a standardized nomenclature for bronchopulmonary segments in 1943, correlating bronchial branching patterns with lung anatomy to guide targeted resections.^[105] In hepatic surgery, Claude Couinaud formalized an eight-segment classification in 1957, delineating functional units based on portal vein and hepatic vein distributions, which facilitated conservative liver resections for benign and malignant lesions.^[14] Early adoption of segmental resection was tempered by significant challenges, including high morbidity from inadequate preoperative imaging and intraoperative hemorrhage control, often limiting its use to benign conditions like bronchiectasis or diverticulitis. Without modern bronchoscopy or cross-sectional imaging, surgeons relied on exploratory thoracotomy or laparotomy, resulting in high complication rates in pulmonary cases during the 1940s and 1950s, particularly for tuberculosis-related resections. Key figures advanced these techniques: Richard H. Overholt extended pulmonary segmentectomy to early lung cancer in the 1950s, reporting survival benefits in select patients unfit for lobectomy.^[106] In colorectal surgery, John C. Goligher refined segmental approaches through his seminal 1967 textbook and clinical trials, emphasizing sharp dissection techniques to improve outcomes in inflammatory and neoplastic disease.^[107] In hepatic surgery, early segmental approaches preceded Couinaud's classification, with pioneers like Wendell Longmire performing wedge resections in the 1940s for benign lesions, evolving toward anatomical segmentectomies by the 1960s for tumors while preserving liver function. For breast cancer, segmental resection, or lumpectomy, gained prominence in the 1970s through trials like the NSABP B-06 (1976), establishing breast-conserving surgery with radiation as equivalent to mastectomy for early-stage disease. In renal surgery, partial nephrectomy dates to the 1880s with Czerny, but segmental techniques for tumors advanced in the mid-20th century, with Robson standardizing it for renal cell carcinoma in 1969 to preserve renal function.

Modern Advances

In the late 1990s and early 2000s, the adoption of video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracic surgery (RATS) marked a significant shift toward minimally invasive approaches for pulmonary segmentectomy, offering reduced postoperative pain, shorter hospital stays, and fewer complications compared to traditional open thoracotomy.^[108] Studies have shown that VATS segmentectomy results in significantly less acute pain and lower rates of pulmonary complications, with one analysis reporting up to a 50% reduction in postoperative pain scores relative to open procedures.^[109] Similarly, RATS has demonstrated comparable short-term outcomes to VATS, including decreased operative morbidity and improved lymph node dissection, while providing enhanced precision in complex anatomical resections.^[110] These techniques have become standard for early-stage non-small cell lung cancer (NSCLC), with meta-analyses confirming their safety and oncologic efficacy.^[111] Advancements in imaging have further refined segmental resection precision, particularly through post-2000 integration of three-dimensional computed tomography (3D-CT) planning and fluorescence-guided techniques. 3D-CT reconstruction enables detailed preoperative visualization of segmental anatomy, facilitating safer navigation during VATS or robotic procedures and reducing conversion rates to lobectomy.^[112] For instance, combining 3D-CT with near-infrared fluorescence (NIF) mapping using indocyanine green (ICG) dye provides real-time intraoperative demarcation of intersegmental planes and tumor margins, minimizing blood loss and operative time in lung segmentectomy.^[113] In colorectal surgery, ICG fluorescence has similarly enhanced vascular assessment during laparoscopic segmental colectomy, improving perfusion evaluation and reducing anastomotic leak risks.^[114] Oncologic validation from large-scale trials has solidified segmental resection's role as an equivalent alternative to more extensive procedures. The CALGB 140503 trial, reported in 2023, demonstrated that segmentectomy is noninferior to lobectomy for overall and disease-free survival in peripheral stage IA NSCLC tumors ≤2 cm, with 5-year overall survival rates of approximately 80% in both arms.^[18] In colorectal cancer, meta-analyses from the 2020s, including those comparing laparoscopic to open approaches for transverse or splenic flexure tumors, have shown equivalent long-term oncologic outcomes, such as similar 5-year survival and recurrence rates, alongside benefits in recovery time.^[115] These findings support broader adoption for organ-preserving surgery in both thoracic and abdominal contexts. Organ-specific innovations include stereotactic body radiotherapy (SBRT) as a nonsurgical alternative for inoperable early-stage lung cancer patients, offering comparable local control to segmentectomy (around 90% at 3 years) but with lower short-term morbidity and preserved pulmonary function.^[116] Enhanced recovery after surgery (ERAS) protocols, implemented post-2010, have optimized postoperative care in segmental resections, reducing complication rates by 30-50% and hospital lengths of stay by 2-3 days through multimodal interventions like early mobilization and opioid minimization in both lung and colorectal procedures.^[117] Looking ahead, artificial intelligence (AI)-assisted tools for 3D segmentation and genomic profiling promise further personalization; AI enhances preoperative planning by automating vessel and tumor delineation with over 95% accuracy, while genomic analysis guides resection extent based on tumor mutation profiles to minimize recurrence risk in colorectal cases.^[118][119]