Surgical Approaches to the Abdomen: Cellotomy and Exposure

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• The midline cellotomy, extending from the xiphoid process to the pubic symphysis, is the standard open surgical approach for canine and feline abdominal exploration and most procedures due to its avascular nature (linea alba) and minimal disruption of segmental neurovascular supply.
• Paramedian cellotomy, incising lateral to the linea alba through the rectus abdominis muscle or sheath, is reserved for specific indications such as lateral abdominal wall access or revision surgery, but carries a higher risk of muscle atrophy and incisional hernia due to potential denervation and complex closure.
• Adequate abdominal exposure is achieved through a combination of appropriate incision length, patient positioning (e.g., Trendelenburg tilt to displace viscera), and effective retraction using self-retaining retractors (e.g., Balfour) and manual instruments, with laparotomy sponges crucial for packing intestines.
• Closure of the linea alba is paramount for abdominal wall integrity, typically performed with a single-layer appositional pattern using absorbable monofilament suture, while subcutaneous and skin layers are closed separately to minimize dead space and promote healing.
• Incisional complications like dehiscence, seroma, and infection are recognized risks, with early detection facilitated by serial monitoring of vital parameters, meticulous wound inspection, and diagnostic tools such as ultrasound or abdominocentesis when indicated.
• Decision-making regarding approach selection, incision extension, and retraction strategies should be guided by anatomical principles and the specific surgical goal, prioritizing patient safety and minimizing iatrogenic injury over prolonged or forceful manipulation.

This article details the standard open surgical approaches to the canine and feline abdomen, with emphasis on midline and paramedian cellotomy techniques. It serves the practicing veterinarian who requires a structured reference for patient positioning, incision planning, and retraction strategies that optimize exposure of specific abdominal organs. The procedural focus is on decision criteria for approach selection, tissue handling, and the mechanical principles that govern exposure, excluding minimally invasive alternatives.

The clinical questions addressed are practical: which incision length and location serve a given diagnostic or therapeutic goal, how to position the patient for consistent access, and which retraction systems and packing techniques convert a modest incision into a workable surgical field. The underlying anatomy of the ventral abdominal wall, including its fascial layers, vascular supply, and innervation, is reviewed first because every technical decision in cellotomy follows from these structural facts.

At a Glance

Surgical Anatomy of the Ventral Abdominal Wall

The ventral abdominal wall consists of four muscle layers, their aponeuroses, and the overlying skin and subcutaneous fat. From superficial to deep, the muscles are the external abdominal oblique, internal abdominal oblique, rectus abdominis, and transversus abdominis. The aponeuroses of the three oblique and transverse muscles interdigitate at the midline to form the linea alba, a dense, relatively avascular collagenous raphe that extends from the xiphoid process to the pubic symphysis.

The rectus abdominis muscle runs parallel to the midline on each side, enclosed within the rectus sheath formed by the aponeurotic layers. The cranial epigastric artery and vein course within the caudal portion of the rectus sheath, while the caudal epigastric vessels enter the sheath cranially. These vessels are relevant when a paramedian incision is made, as the rectus muscle must be retracted laterally instead of transected to avoid hemorrhage.

Innervation of the ventral abdominal wall arises from the thoracolumbar spinal nerves, specifically T7 through L3, which course between the internal oblique and transversus abdominis layers before penetrating the rectus sheath. A paramedian incision that transects the rectus muscle or its segmental nerves can produce denervation and subsequent muscle atrophy, which is one reason the midline approach is preferred for most procedures.

The parietal peritoneum lines the deep surface of the abdominal wall and is incised with the linea alba during a standard cellotomy. In the cat, the ventral abdominal wall is thinner and more pliable than in the dog, and the linea alba is correspondingly narrower, which makes accurate midline identification more demanding in obese feline patients.

Principles of Exposure

Adequate exposure is the product of three variables: incision length, patient positioning, and retraction. The surgeon controls all three, and each can compensate partially for deficiencies in the others. A longer incision provides more direct access but increases wound complications, so the surgeon should plan the incision to match the procedure while retaining the option to extend it.

The mechanical goal of retraction is to convert the three-dimensional abdominal cavity into a two-dimensional working field. This requires displacing the body wall laterally and the viscera dorsally or to one side. The liver, spleen, and omentum are mobile and can be packed away, whereas the kidneys, adrenal glands, and retroperitoneal structures are fixed and require positioning of the patient or the incision to bring them into view.

Gravity is a retractor that never fatigues. Tilting the surgical table changes which organs fall away from the incision. For example, a slight Trendelenburg position (head down) shifts the liver and diaphragm cranially, improving access to the caudal abdomen, while a reverse Trendelenburg position improves cranial abdominal exposure. Lateral tilting of 10 to 15 degrees is often sufficient to displace the intestines and allow access to the kidneys or adrenal glands without additional manual retraction.

Midline Cellotomy

The midline cellotomy is the default approach for exploratory laparotomy and for most intra-abdominal procedures in dogs and cats. The patient is placed in dorsal recumbency, and the ventral abdomen is clipped from the xiphoid process to the pubis, with the clip extending laterally to the level of the nipples. Aseptic preparation follows standard protocols as described in professional practice resources from the American Veterinary Medical Association.

The skin incision follows the midline from the xiphoid to the pubis, or a shorter segment centered over the organ of interest. The subcutaneous fat is incised along the same line, and the linea alba is identified. In thin patients the linea alba is visible as a white line through the subcutaneous tissue. In obese patients, the surgeon may need to palpate the xiphoid and pubis and incise the fat in a single stroke down to the linea alba, then confirm the midline by the absence of the rectus abdominis muscle fibers on either side.

The linea alba is incised with a scalpel at its cranial or caudal extent, taking care to avoid the underlying viscera. A small stab incision is made through the linea alba and peritoneum, and the surgeon uses a finger or forceps to lift the abdominal wall while extending the incision with scissors. The falciform ligament, a fat-laden peritoneal fold, is often encountered in the cranial abdomen and may be resected or retracted to improve exposure.

Closure of the midline incision is performed with a simple continuous or interrupted pattern using absorbable monofilament suture. The linea alba is the only layer that must be closed for strength, and the subcutaneous tissue and skin are closed separately. The American College of Veterinary Surgeons notes that proper closure technique and attention to tissue handling are critical determinants of postoperative recovery and wound healing.

Paramedian Cellotomy

The paramedian approach places the incision through the rectus abdominis muscle or its sheath, lateral to the linea alba. It is used less frequently than the midline approach, but it has specific indications. These include access to the lateral abdominal wall, drainage of localized abscesses, and revision surgery where the midline has been compromised by previous incisions, infection, or dehiscence.

The patient is positioned in dorsal recumbency, and the incision is made 1 to 2 cm lateral to the midline, parallel to the linea alba. The skin and subcutaneous tissue are incised, and the rectus sheath is opened. The rectus abdominis muscle is retracted laterally instead of transected to preserve its innervation and vascular supply. The deep leaf of the rectus sheath and the peritoneum are then incised to enter the abdominal cavity.

Closure of a paramedian incision requires apposition of the deep and superficial leaves of the rectus sheath as separate layers, which is more time-consuming than midline closure and carries a higher risk of incisional hernia if the sheath is not closed securely. The paramedian approach also violates the segmental neurovascular supply to the rectus muscle if the incision is long, which can lead to muscle atrophy and weakening of the abdominal wall over time. For these reasons, the paramedian approach is reserved for cases where the midline is unavailable or where lateral exposure is specifically required.

Retraction Techniques and Instrumentation

Self-retaining retractors are the primary instruments for maintaining abdominal exposure. The Balfour retractor, with its adjustable side blades and a third blade that can be positioned cranially or caudally, is the most versatile for midline cellotomy in dogs. The Gosset retractor is a lighter alternative for smaller patients. In cats, a small Balfour or a Gelpi retractor may be sufficient, and the surgeon must take care not to over-distract the thin body wall.

Manual retraction with malleable retractors or abdominal wall retractors is used for specific organ exposure. A malleable retractor placed over a laparotomy sponge can gently displace the spleen, liver, or intestines without crushing them. The surgeon should change the position of manual retractors periodically to avoid pressure necrosis of the body wall or viscera.

Laparotomy sponges are essential for packing the intestines out of the surgical field. The greater omentum is reflected cranially or caudally as needed, and the intestines are gently lifted and packed into the dorsal abdomen or outside the incision within a moistened sponge. The spleen is mobilized by dividing its attachments to the greater omentum when necessary, and the liver lobes are retracted with malleable retractors or by packing the stomach and duodenum caudally.

The choice of retraction system depends on the procedure and the size of the patient. For a deep-chested dog undergoing a portosystemic shunt ligation, a Balfour retractor with a third blade placed cranially provides the exposure needed for the cranial abdomen. For a feline pyometra, a small Balfour or simple manual retraction with a malleable retractor is usually adequate. The surgeon should have both self-retaining and manual options available and should not hesitate to extend the incision when exposure is inadequate, as struggling with poor exposure is more harmful to the patient than a slightly longer incision.

Incision Planning and Patient Preparation

The choice of incision length and position follows directly from the suspected or confirmed pathology. A complete abdominal exploration requires an incision that extends from the xiphoid process to the pubic brim. This approach provides access to the entire peritoneal cavity and is the standard for trauma, septic peritonitis, and undiagnosed gastrointestinal disease. For a targeted procedure, such as ovariectomy or cystotomy, a shorter incision centerd over the target organ is acceptable, but the surgeon must be prepared to extend the incision if findings differ from preoperative imaging.

Patient preparation begins with clip and scrub of the entire ventral abdomen from the mid-thorax to the pubis. The prep should extend laterally to the flanks to accommodate potential extension of the incision or placement of drains. In male dogs, the prep should include the prepuce and the area caudal to the scrotum, as the prepuce is retracted laterally or secured with a stay suture to keep it out of the surgical field. In female dogs, the mammary chain should be included in the prep if mammary neoplasia is a differential, as mastectomy may be combined with cellotomy.

Antibiotic prophylaxis follows standard perioperative protocols. A single dose of a first-generation cephalosporin given at induction is appropriate for clean-contaminated procedures. Redosing is indicated if surgery exceeds 90 to 120 minutes or if blood loss is significant. The American College of Veterinary Surgeons specialty resources provide guidance on perioperative antimicrobial use in the context of specific surgical conditions.

Step-by-Step Midline Cellotomy Checklist

The following sequence assumes a standard ventral midline approach in dorsal recumbency.

1. Confirm patient positioning. The spine must be straight, and the sternum and pubis must lie in the same sagittal plane. Tilting the table slightly toward the surgeon improves visualization of deep pelvic structures.
2. Apply the final skin prep and drape with four towels and a fenestrated sheet. Secure the towels with towel clamps or skin staples.
3. Incise the skin with a No. 10 blade from the xiphoid to the pubis. For a limited approach, mark the intended incision with a sterile marker or by gentle pressure from a scalpel handle before cutting.
4. Deepen the incision through the subcutaneous fat to expose the linea alba. In obese patients, use blunt dissection with Metzenbaum scissors to identify the linea, which appears as a white fibrous band. The subcutaneous fat is often thicker cranial to the umbilicus.
5. Identify the linea alba and pick it up with thumb forceps or a Backhaus towel clamp. Make a small stab incision through the linea with a No. 11 blade, angling the blade away from the underlying viscera.
6. Confirm entry into the peritoneal cavity. A rush of air or the appearance of omental fat confirms penetration. If the bladder is distended, it may be visible immediately beneath the incision.
7. Extend the linea incision cranially and caudally using Mayo scissors. Lift the abdominal wall with the non-dominant hand or with two towel clamps to protect the viscera. The assistant should keep the scissors tips elevated.
8. Place a Balfour retractor or stay sutures to maintain exposure. Moistened laparotomy sponges are packed around the wound edges to protect the viscera and absorb blood.
9. Perform a systematic exploration of the abdomen. The standard sequence is: liver and gallbladder, stomach and spleen, duodenum and pancreas, jejunum and ileum, caecum and colon, kidneys and ureters, bladder and urethra, prostate or uterus and ovaries, and the mesenteric lymph nodes.
10. At closure, count all sponges and instruments. Irrigate the abdomen with warm sterile saline if contamination has occurred. Close the linea alba with a continuous or interrupted pattern using monofilament absorbable suture. The suture should incorporate the full thickness of the linea, but not the underlying muscle or peritoneum alone, as this increases the risk of dehiscence.
11. Close the subcutaneous layer if dead space is present, then close the skin with a continuous intradermal pattern or skin staples.

Approach Modifications for Specific Organ Access

The midline incision can be extended or repositioned to improve access to specific regions. The following table summarizes the most common modifications.

The decision to extend an incision should be made early. Struggling with inadequate exposure prolongs anesthesia and increases the risk of iatrogenic injury. If the target organ cannot be exteriorised with gentle traction, extend the incision before attempting further dissection.

Retraction Strategies and Positioning Aids

Self-retaining retractors are preferred for prolonged procedures because they free the assistant's hands. The Balfour retractor is the most versatile for midline cellotomy. Its adjustable side blades retract the abdominal wall laterally, and the center blade can be positioned to retract the bladder or uterus cranially or caudally. The Gosset retractor is a lighter alternative for smaller patients or shorter incisions.

Manual retraction with malleable retractors or Deaver retractors is useful for deep pelvic or cranial abdominal exposure. The assistant must maintain steady, even traction and reposition the retractor as the surgical field changes. Overzealous retraction can cause neuropraxia of the femoral nerve or trauma to the spleen.

Positioning aids are underused. Tilting the table 10 to 15 degrees to the side moves the intestines by gravity and can dramatically improve exposure of the contralateral structures. A sandbag or rolled towel placed under the lumbar spine elevates the abdomen and brings the kidneys and adrenal glands into a more superficial plane. For cranial abdominal procedures, a slight head-up tilt (Trendelenburg reverse) allows the intestines to fall caudally.

Moistened laparotomy sponges are essential for packing off the intestines. They should be placed gently, without excessive force, and counted before and after use. The use of a wound retractor, such as a ring retractor, provides atraumatic circumferential retraction and is particularly useful in obese patients or when the abdominal wall is thick.

Monitoring and Documentation During Cellotomy

Intraoperative monitoring focuses on cardiovascular stability, hemorrhage, and tissue perfusion. Direct arterial blood pressure measurement is preferred for major abdominal procedures, as indirect oscillometric readings become unreliable during hypotension. Central venous pressure monitoring is indicated in patients with suspected right-sided heart failure or during massive fluid resuscitation.

The surgeon should monitor the color and perfusion of the viscera. Pale or mottled intestines suggest hypoperfusion or thromboembolism. The spleen should be inspected for capsular tears, and the liver for color and texture changes consistent with congestion or cirrhosis.

Documentation should include the following elements:

• Preoperative diagnosis and the indication for surgery
• Incision type and length
• Findings at exploration, including any abnormalities and their location
• Procedures performed, including biopsies and the number of samples taken
• Intraoperative complications, such as hemorrhage or iatrogenic injury
• Suture materials and patterns used for closure
• Estimated blood loss and fluid therapy administered
• Postoperative plan, including analgesia and monitoring frequency

The MSD Veterinary Manual professional edition provides guidance on postoperative care and complication management for abdominal surgery. Accurate records support continuity of care and are essential for medicolegal purposes. Photographs of abnormal findings are useful for client communication and for referral if a second opinion is sought.

The choice of closure suture depends on the patient's size, the surgeon's preference, and the anticipated healing time. Polydioxanone or polyglyconate in sizes 2-0 to 0 are appropriate for most dogs and cats. A simple continuous pattern is efficient and provides a secure closure when placed correctly. In patients with poor tissue quality, such as those with peritonitis or chronic corticosteroid use, a far-far-near-near or simple interrupted pattern may be preferred to reduce the risk of suture pull-through.

Recognized Complications and Early Detection

Incisional complications after cellotomy are uncommon but recognizable. Seroma formation presents as a fluctuant, non-painful swelling along the incision line, typically appearing 48 to 72 hours postoperatively. Detection relies on palpation and, when uncertain, ultrasound-guided aspiration to distinguish seroma from hernia or abscess. Wound dehiscence of the subcutaneous layer presents with serosanguineous discharge and a palpable defect, full-thickness dehiscence with omental or visceral protrusion demands immediate surgical revision.

Hemorrhage from the linea alba or subcutaneous vessels may manifest as progressive swelling, tachycardia, pale mucous membranes, or a falling hematocrit. The rectus sheath and external pudendal vessels are the most common sources. Early detection requires serial assessment of vital parameters and incision inspection during the first 12 to 24 hours. Retroperitoneal or mesenteric bleeding may not be visible externally and is identified through abdominal ultrasound or computed tomography when clinical signs suggest ongoing loss.

Peritonitis, whether from leakage at an enterotomy site or from intraoperative contamination, presents with fever, lethargy, abdominal pain, and progressive leukopaenia or toxic neutrophils. Abdominocentesis with fluid analysis and culture is the discriminating test. A neutrophil count above 5000 cells per microlitre with intracellular bacteria confirms septic peritonitis and mandates exploratory laparotomy. The ACVS small animal surgical resources describe postoperative monitoring parameters that support early recognition of these complications.

Incisional infection is detected by erythema, heat, purulent discharge, or wound odour, usually after day 3. Risk factors include prolonged surgery, corticosteroid use, and contamination at closure. The MSD Veterinary Manual provides guidance on recognizing and managing surgical site infections in small animals.

Common Errors and Corrective Actions

Less experienced surgeons frequently make the incision too far lateral, entering the rectus sheath instead of the linea alba. This complicates closure and increases hemorrhage. Corrective action is to identify the linea alba as a thin white raphe and incise precisely along it. Another common error is failing to extend the incision adequately for the intended procedure, leading to excessive traction and tissue trauma. The incision should be long enough to permit exposure without forceful retraction.

Incomplete closure of the linea alba, particularly at the cranial and caudal extremes, predisposes to hernia formation. The surgeon should place the first and last sutures beyond the visible incision ends. Excessive tension on closure causes tissue tearing and subsequent dehiscence. Use a tension-relieving pattern or extend the incision instead of pulling tight.

Limitations of Current Evidence

Comparative studies of midline versus paramedian approaches in dogs and cats are limited, and most published guidance reflects expert opinion instead of randomised trials. Wound complication rates for paramedian approaches are reported inconsistently, and the purported advantage of reduced incisional hernia risk lacks robust supporting data. The ACVS specialist summaries acknowledge that approach selection is often based on surgeon preference and specific organ access instead of evidence of superior outcomes.

Evidence on optimal suture material and closure technique for the linea alba in cats is particularly sparse. Opinions differ on whether simple continuous or interrupted patterns reduce dehiscence risk, and no consensus exists on the role of far-far-near-near tension patterns in routine closures. Surgeons should rely on their training and institutional protocols while recognizing that the evidence base does not strongly favour one method.

Expert opinion also differs on the necessity of routine omentalisation of abdominal incisions and on the value of closed-suction drainage after contaminated procedures. These decisions remain individualised based on intraoperative findings.

Referral, Consultation, and Reporting

Referral to a board-certified surgeon is warranted when exposure cannot be achieved safely, when the procedure exceeds the clinician's training, or when complications such as uncontrollable hemorrhage, suspected septic peritonitis, or major vascular injury arise. Early referral is preferable to attempting salvage in unfamiliar territory. The AVMA professional practice resources offer guidance on scope of practice and when specialist consultation is appropriate.

Laboratory involvement is indicated for cytological and microbiological analysis of peritoneal fluid, histopathology of resected masses, and coagulation profiling when hemorrhagic complications are suspected. Clinical pathology support should be requested before surgery when coagulopathy is suspected, and postoperatively when peritonitis or sepsis is considered.

Regulatory reporting obligations vary by jurisdiction. Reportable diseases that may be encountered during abdominal exploration, such as certain zoonotic or notifiable conditions, should be reported according to local requirements. The WOAH terrestrial animal health standards describe international reporting frameworks for notifiable diseases, and clinicians should consult their regional veterinary authority for specific obligations.

Frequently Asked Questions

How do I decide between a midline and a paramedian approach when resources or time are limited?

The midline approach is the default for most surgeons because it avoids major vessels and allows extension from xiphoid to pubis with minimal dissection. Choose a paramedian approach only when a specific lateralised lesion, such as a focal adrenal or renal mass, demands direct access and you are prepared for the additional muscle dissection and closure time. When operating time is short or hemorrhage risk is high, midline is safer. The American College of Veterinary Surgeons resources describe midline cellotomy as the standard for exploratory surgery, which supports using it whenever the diagnosis is uncertain or the procedure is time-sensitive.

What can I do when a self-retaining retractor or ring retractor is unavailable?

Manual retraction with handheld retractors is adequate for most procedures, though it requires an assistant and causes more fatigue during long surgeries. Place moistened laparotomy sponges around the wound edges to protect the body wall and reduce trauma from retractor blades. If a Balfour retractor is missing, use two Gelpi retractors placed at opposite ends of the incision, or create a makeshift stay suture through the linea alba and tie it to a towel clamp secured to the drapes. For cranial abdominal exposure, a malleable retractor held by an assistant can substitute for a fixed blade. The MSD Veterinary Manual notes that adequate exposure depends more on correct patient positioning and incision length than on specialised retraction equipment.

Does the approach differ between cats and dogs?

The midline approach is anatomically similar in both species, but cats have a thinner linea alba and less subcutaneous fat, so closure requires smaller suture bites and more careful tension to avoid tearing. Feline abdominal organs are more mobile, which can make stabilization of the spleen or liver more challenging during retraction. Cats also tolerate longer anesthesia less predictably, so minimize time spent on exposure and close efficiently. The American College of Veterinary Surgeons resources cover feline surgical considerations within their procedure summaries, and the MSD Veterinary Manual provides species-specific guidance on perioperative care that affects how long you can safely maintain exposure.

What should I record in the surgical log after a cellotomy?

Record the incision location and length, the method of closure including suture type and pattern, any difficulty encountered during exposure, and the specific organs inspected. Note the position of any retractors used and the duration of retraction, because prolonged traction on the spleen or mesentery can cause ischemia that may not be visible at closure. Document any incidental findings, such as adhesions or enlarged lymph nodes, even if they were not the primary reason for surgery. The AVMA practice resources emphasize accurate medical records as a professional obligation, and a detailed operative note supports postoperative decision-making if complications arise.

How do I explain a prolonged or difficult exposure to a client after surgery?

Use plain language that separates the surgical plan from the intraoperative findings. State that the incision was longer than anticipated or that additional retraction was needed to see the affected organ safely. Explain that the goal was to avoid blind manipulation, which carries a higher risk of organ damage. Avoid technical terms such as "self-retaining retractor" unless you define them. The AVMA practice resources provide communication guidance for client discussions, and the American College of Veterinary Surgeons resources describe expected outcomes and postoperative care that can help frame the conversation around recovery instead of the difficulty of exposure.

When should I stop extending the incision and consider a different strategy?

Stop extending when the incision reaches the xiphoid or pubis and the target organ still cannot be visualized. At that point, reassess the diagnosis, consider whether the organ has migrated, and evaluate whether a paramedian or flank approach would provide better access. Continuing to extend beyond the standard limits increases wound complications without improving exposure. If the organ is adhered or fixed, mobilize surrounding attachments instead of enlarging the incision further. The MSD Veterinary Manual notes that surgical planning should include contingency options, and the WOAH terrestrial animal health standards reinforce the importance of documenting deviations from standard procedures in the medical record.

Related Clinical & Scientific Guides

• Perioperative Antibiotic Prophylaxis: Timing and Selection
• Surgical Approaches to the Femur and Stifle
• Fracture Healing Assessment: Radiographic and Clinical Evaluation

References and Further Reading

• American College of Veterinary Surgeons Animal Health Resources. American College of Veterinary Surgeons.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.
• WOAH Terrestrial Animal Health Code. WOAH.

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• Surgical Approaches to the Femur and Stifle
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• Surgical Approaches to the Mandible and Maxilla

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.