Diagnostic Laparoscopy
Rachel Barron
General Principles
Diagnostic laparoscopy is the surgical examination of the pelvis and abdomen with the intent to diagnose various pathologies.
Differential Diagnosis
Ruptured ectopic pregnancy
Adnexal masses—benign versus malignant
Adnexal torsion
Endometriosis
Anatomic Considerations
Aorta
The aortic bifurcation is located cephalad to the umbilicus in 90% of nonobese, supine patients.
In a patient with body mass index (BMI) <25 kg/m2, the abdominal wall is approximately 2 to 3 cm thick. At a 90-degree angle, the distance to the bifurcation is between 6 and 8 cm and directly correlates to the patient’s BMI. Therefore, an entry angle of 45 degrees is recommended to avoid vascular injury.
In a patient with BMI >25 and >30 kg/m2, the distance from the umbilicus to the aortic bifurcation averages 10 and 13 cm, respectively.
Inferior epigastric vessels
See Figure 5.1.
The deep inferior epigastric vessels originate from external iliac vessels and travel along the anterior abdominal wall on the inferior side of the rectus abdominus.
Their path begins medial to the insertion of the round ligament into the deep inguinal ring.
At the level of pubic symphysis, the vessels are lateral to the rectus abdominis.
At the level of the anterior superior iliac spine (ASIS), the vessels are an average of 3.5 (2.6 to 5.5) cm from the midline.
During laparoscopy, the deep inferior epigastric vessels can be identified in the lateral peritoneal umbilical folds bilaterally.
Iliohypogastric and ilioguinal nerves
The iliohyogastric nerve provides sensory innervation to the oblique abdominal muscles and the suprapubic skin.
The ilioguinal nerve provides sensory to the transversus abdominis, internal oblique, skin of medial thigh, and the vulva.
Classically, when a nerve has been injured or entrapped, patients report a burning sensation near the incision sites that radiates toward the groin.
Both nerves originate from L1 vertebra, after emerging from the lateral border of the psoas muscle. They wrap around the iliac crest to pierce through the transversus abdominis and internal oblique.
The ilioinguinal nerves emerge 3.1 cm medial and 3.7 cm inferior to the ASIS. The iliohypogastric emerges 2.1 cm medial and 1 cm inferior to the ASIS.
Both nerves emerge near classic locations for lateral trocar placement.
 Figure 5.1. Laparoscopic view of the anterior abdominal wall: Inferior epigastrics traveling through lateral umbilical fold. |
Imaging and Other Diagnostics
Transvaginal pelvic ultrasound is the imaging modality of choice.
The primary entry site may be altered by a pelvic mass, an enlarged uterus, or suspected adhesions revealed by ultrasound.
A visceral slide test performed with ultrasound can be used to preoperatively identify dense subumbilical adhesions in a high-risk patient. During this test, an echogenic area of bowel or omentum is identified near the umbilicus on ultrasound. The patient then performs exaggerated inhalation and exhalation. Longitudinal movement of this location greater than 1 cm corresponds to a low risk of obliterating subumbilical adhesions.
A urine pregnancy test is recommended for premenopausal patients who have a uterus and have not undergone a sterilization procedure.
A positive pregnancy test does not contraindicate surgery, but intrauterine procedures should not be performed.
Preoperative Planning
Obtain a surgical history. History of a prior laparotomy or multiple surgeries is a significant risk factor for laparoscopic complications.
Obtain a medical history, especially note cardiovascular and pulmonary diseases.
Trendelenburg position may be limited in a patient with poor cardiopulmonary function or extreme obesity. It is important to preoperatively counsel these patients about these inherent limitations and the possibility of conversion to laparotomy.
Surgical Management
Positioning
Proper patient positioning is essential to ensure patient safety.
Position the patient in low lithotomy position using adjustable stirrups. These stirrups allow for quick and easy position changes and should neutralize pressure points from the patient’s own leg weight.
See Figure 5.2.
Ideal low lithotomy position:
The hips are flexed with minimal internal or external rotation. Hip flexion should not be less than 60 degrees and preferably set at 80 to 90 degrees in high lithotomy to avoid compression of the femoral nerve. The hips should also not be extended beyond 170 degrees in low lithotomy as this places strain on the lumbar spine.
Similarly, avoid excessive abduction of the legs. The angle between thighs should be limited to 90 degrees.
Knees should be flexed and padded with foam to avoid lateral compression which can result in a peroneal nerve injury. Knee flexion should be 90 to 120 degrees. Increased knee flexion can put strain on the femoral nerve and promote venous stasis in the lower leg.
Use an egg crate or gel cover on the top of the surgical table and in direct contact to the patient’s back to prevent the patient from slipping while in the Trendelenburg position. Avoid using shoulder supports to stabilize the patient as these supports can cause brachial plexus injury. A padded chest strap or large Velcro strap can be placed across the patient’s chest and secured to the surgical bedframe to prevent slippage in the obese, but should also allow for maximum ventilation.
Tuck the arms to the patient’s side using disposable positioning systems, sheets, foam, or a combination of the above. Place the wrist in a neutral position with the thumb anterior. Place padding under the wrist and elbow to avoid ulnar nerve compression. Take great care not to compress peripheral intravenous access and to cushion the patient’s fingers from the table joint. In obese patients, use low-profile surgical sleds or bed extensions to provide extra support and space to accommodate increased patient habitus.
This position allows the surgeon closer proximity to the patient and protects the patient’s hands, wrists, and joints.
Ensure the bed is level and the patient is lying flat.
Avoid Trendelenburg position initially as this position shifts the aortic bifurcation closer to the umbilicus and increases the risk of aortic injury.
Confirm a nasogastric tube and Foley catheter are inserted as distention of these organs increases the risk of injury during surgical entry.
Place a uterine manipulator to facilitate uterine mobility.
Complex manipulators have been designed to aid in more complicated operative procedures. In the case of a diagnostic procedure, consider a reusable low-cost option such as a cervical dilator secured to a tenaculum or a Hulka tenaculum.
 Figure 5.2. Proper positioning in dorsal lithotomy using padded stirrups. A. The patient’s elbow is tucked at her side with her hand in neutral position. Additional foam padding is placed on the most lateral aspects of the elbows and hand prior to securing or “tucking” the arm. B. Hip flexion: This angle can vary widely for laparoscopic and vaginal surgeries. However, at its maximum limits should range from 60 to 170 degrees with flexion preferably at 80–90s degrees in high lithotomy. C. Hip abduction: The angle between the thighs should be less than 90 degrees. D. Hip rotation: Maintain minimal rotation. E. Knee flexion: Thigh-to-calf angle should range between 90 and 120 degrees. Additional foam padding is placed on the lateral aspect of each knee to protect the peroneal nerve. F. Note an egg crate or additional gel table padding is placed to reduce patient slippage. |
Approach
Entry into the peritoneal cavity and establishment of pneumoperitoneum is the essential first step to all laparoscopies. It also carries the highest risk.
The primary entry site is typically at the umbilicus or Palmer’s point.
Palmer’s point is located 3 cm below the costal margin in the midclavicular line. This site has significantly less adipose tissue compared to the periumbilical area and typically has a smaller skin to peritoneum distance. It may be preferable in obese patients.
Palmer’s point can be utilized when there is concern for adhesions from prior laparotomy (including cesarean section), large fibroid uterus, pelvic mass, or prior umbilical hernia repair with mesh.
The stomach and liver are the closest structures and are at increased risk of injury.
Relative contraindications to Palmer’s point include splenomegaly, hepatomegaly, and a known left upper quadrant mass. Adhesions from prior upper abdominal surgery should also be considered.
A supraumbilical site can also be used for the same preoperative risks. This site is located 3 to 5 cm above the umbilicus in the midline.
Adhesions in the infraumbilical area can be as high as 50% after prior low transverse laparotomy and up to 90% after prior midline laparotomy.
Entry techniques in laparoscopy are typically classified as closed or open entry. Open entry refers to a mini-laparotomy or Hasson approach. Closed entry is the blind insertion of an instrument into the peritoneal cavity. The most common methods of both types of techniques will be described below.
Multiple studies have affirmed that over 50% of major complications, specifically bowel and vascular injury, occur at initial entry.
No method has been proven to be superior at preventing injuries. We recommend perfecting one technique to acquire mastery and proficiency, then gradually adding other techniques to your surgical repertoire.
Consistency, experience, and good technique lead to safe entry, no matter the approach.
Procedures and Techniques (Video 5.1)Veress needle
The Veress needle is a thin long needle with a spring-loaded blunt tip that is used for closed entry. Once this needle is passed into the peritoneal cavity, it is then used to insufflate the abdomen prior to trocar insertion.
To insert the Veress needle, grasp and elevate the abdominal wall. A small skin incision may be made.
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