https://en.wikipedia.org/wiki/Veress_needle

A fact: There is no such thing as the "one-angle-works-everywhere" Veress needle insertion method.

The diagrams of umbilical puncture shown in textbooks are always neat and straightforward - a needle is inserted obliquely, and the abdominal cavity suddenly opens up. But in reality, the human body is like this: some people have thin abdominal walls like a layer of wet paper (the aorta is almost touching the peritoneum), some have subcutaneous fat up to 10 cm thick (the umbilicus is dragged deep into the fatty sea), and some have their abdomens wrapped with old surgical adhesions left from previous operations. Treating everyone with the same technique is to hand the patient's safety over to luck.

BMI Stratification: Anatomical Landmarks Shift with Body Weight

➤ Normal/underweight patients (BMI < 25)

Core risk: The deep major blood vessels are too close together.

Just below the umbilicus is precisely the site of the abdominal aorta bifurcation (at approximately the L4 level). In thin patients, there is less retroperitoneal fat, and the distance from the aortic bifurcation to the inner side of the umbilical wall may be only 1–2 cm. At this point:

The abdominal wall must be forcefully lifted using a towel clamp to artificially create a safe distance.

The needle insertion angle should be set at 45 degrees and tilted towards the sacrum, allowing the needle path to follow an "inward arc" on the sagittal plane, avoiding the deep vessels in the midline.

It is strictly prohibited to perform a 90-degree vertical thrust without any lifting - that would be a direct shortcut to the aorta.

Classic rule: Thin patient = lift high, angle shallow, go slow.

➤ Overweight/obese patients (BMI 25–35+)

Key risks: Needle length insufficient + Needle path deviates within the fat layer + Anatomical landmarks "sink" downward.

Research shows that as BMI increases, the position of the aortic bifurcation relative to the navel actually "moves upward" - in obese women, the bifurcation can be 2-3 cm above the navel, making the navel a relatively safe lower entry point.

Strategy Reversal:

The needle insertion angle is adjusted to be closer to a 90° vertical position (approximately 70–90°), because the thick subcutaneous layer is naturally inclined. Making an additional sharp cut would only cause the needle to "float" in the fat and change its direction.

A longer specification of the Veress needle (120–150mm) is selected to ensure that it can truly penetrate into the abdominal cavity rather than stopping in the pre-peritoneal area.

The umbilical incision may require a deeper blunt dissection to reach the fascial sensory surface.

➤ Extreme emaciation (emaciation < 18)

This is one of the most dangerous subtypes - with almost no fat padding for cushioning, the intestinal tube can directly adhere to the posterior peritoneum.

It is strongly recommended to consider the Hasson open method as an alternative or at least to conduct an ultrasound assessment of the intestinal free movement before making a decision.

The retraction must be more thorough, and the needle insertion should be "progressive" (a small amount of insertion → stop → perception → then insert again).

Previous History of Abdominal Surgery: The Invisible Traps of Adhesions

"I'll just make a small incision at the navel. Shouldn't that be okay?" - This statement conceals numerous cases of small intestine perforation.

The rule is:

History of low midline incision (lower abdominal cesarean section, appendectomy, cystectomy) → Significantly increased probability of adhesions below the umbilicus → Increased risk of blind umbilical Veress puncture.

History of upper abdominal surgery (partial gastrectomy, cholecystectomy via upper midline) → More dangerous in the area above the umbilicus.

Response Strategies:

Palmer's approach: At approximately 3 cm below the midline of the left clavicle, this is used as an alternative puncture site, bypassing the suspected midline adhesion area. The stomach here must be confirmed not to be overly distended (preoperative gastric tube insertion for decompression).

The principle of avoiding scars by at least 3 cm.

Centers with the necessary conditions will perform preoperative abdominal ultrasound or CT to assess the location of abdominal wall adhesions/hernias.

Special Population Quick Reference Guide

First surgery / normal BMI ✅ Standard protocol 45° + lift + three-step verification Obese (BMI > 30) ✅ Feasible but requires a longer needle ≈ 90° vertical + longer needle + ensure true penetration Extremely emaciated ⚠️ Caution: cautious lift or switch to Hasson Multiple lower abdominal surgery history ❌ / ⚠️ Not recommended for umbilical Palmer's point or Hasson Pregnancy (2nd/3rd trimester) ❌ Absolutely avoid umbilical / midline blind puncture → ultrasound-guided abdominal approach or Hasson Large abdominal wall hernia ❌ Hasson or directional approach away from the hernia sac

Complication Spectrum: Knowing What They Look Like Enables You to Detect Them in Advance

Even if the technique is correct, the inherent risk profile of the Veress needle still needs to be engraved in the minds of every operator:

Vascular injury (<0.5% but potentially fatal): The most common type is the inferior epigastric artery (deviating off the midline), iliac vessels (needle angle too steep and too deep), and rare cases involve the aorta/IVC (not pulled out + vertical sharp insertion).

Intestinal perforation: It often occurs when the adherent intestinal loops are pinned to the puncture path.

Subcutaneous emphysema: The needle tip retracts into the preperitoneal/subcutaneous space but is not detected → continue inflating → gas spreads in the fascial layer → facial swelling, mediastinal emphysema, and interference with ventilation.

Gas embolism (extremely rare ≈ 1/100,000): If the needle tip enters a venous branch and delivers high-flow CO₂ → sudden drop in SpO₂, ETCO₂, and circulatory collapse → immediately stop the gas supply, adopt left lateral position, and perform cardiopulmonary resuscitation.