First ever description of a posture dependent orthostatic splenic vein compression in 2 female patients

The splenic vein runs horizontally from the left upper quadrant to the right upper quadrant connecting spleen and liver. Its usual position is inbetween the celiac trunk and the superior mesenteric artery – untouched by both arteries.

Simplified anatomy of the relevant vessels for splenic vein compression under normal cirumstances (author’s drawing)

1.

Gradually increasing, unbearable pain in the left flank only when standing or sitting due to orthostatic splenic vein compression by the common hepatic artery  – the left branch of the celiac trunk

I report here on another female patient who was diagnosed by functional colour Doppler sonography with the following abdominal vascular compression syndromes:

1. Celiac artery compression syndrome (MALS)
2. Lordogenetic left renal vein compression (erroneously aka nutcracker syndrome)
3. May Thurner syndrome

Indication for the operation was the excruciating post-prandial pain and vomiting with substantial weight loss.

The patient opted against a decompression of the left common iliac vein and was thus operated with an excision of the median arcuate ligament to reduce her celiac artery compression and with a shielding of the left renal vein by a PTFE sheath surrounding the vein to prevent further compression.

The PixelFlux measurements clearly show an effect of the protection of the left renal vein by the PTFE sheath covering onto the left renal perfusion.

Preoperative renal PixelFlux measurement in a horizontal posture:

19 months post-operative renal PixelFlux measurement

The ratio of peripheral to deep cortical perfusion improved in the left kidney while lying from 0.42 to 0.55 pointing to the successful decompression of the left renal vein. The distal parenchymal vessels are especially pressure senitive and loose perfusion volume if the counterpressure from a congested renal vein is high which is a sign of a high pressure grtadient at the compression site. Thus, a lower ratio of peripheral / central renal perfusion points to an elevated venous pressure. The postoperative improvement can thus be easily measured with PixelFlux. Here the improvement is quite clear.

The celiac trunk decompression was also successful with respect to the complete disappearance of all symptoms, the weight gain, and a complete relief of abdominal pain.

Nevertheless, the patient now developed a new posture-dependent left flank pain due to a so far undescribed compression of the splenic vein.

While lying horizontally the patient was completely pain free and the splenic vein showed a sufficient diameter throughout with a flow velocity at the compression site measuring 78 cm/s. The flow pattern is unremarkable without strong pulsations:

Patient in horizontal posture: non-compressed splenic vein with a maximum flow velocity of 78 cm/s at the later compression site

In a horizontal posture the left part of the splenic vein has a flow velocity of 30 cm/s

In a horizontal posture: no relevent diameter reduction of the splenic vein

While standing a strong compression of the splenic vein develops from 8 mm to 0.8 mm

The splenic vein was compressed from behind by the common hepatic artery resulting in a massive flow acceleration to 360 cm/s at the compression site. With the PixelFlux measurement of the splenic perfusion it became evident that the congestion of the spleen is related to the simultaneously increasing left flank pain.

In a standing posture: splenic vein is now compressed from behind by the common hepatic artery

While standing: significant localized diameter reduction of the splenic vein due to the left branch of the celiac trunk

While standing: even slightly off the compression site’s maximum the flow is accelerated to enormous 284 cm/s

The diagram above compares the splenic tissue perfusion in equal-sized subcapsular layers at different depths. The location of the tissue examined is 4 cm cranial to the lower pole of the spleen. While standing the tiniest  and most pressure-sensitive vessels in the 0 – 5 mm subcapsular layer loose most of their flow volume. Simultaneously the pain in the left upper flank increased.

PixelFlux measurement of the splenic tissue perfusion – substantially dropping while standing

It can be clearly shown that while standing there is a significant perfusion reduction especially of the pressure-sensitive subcapsular vessels which show a perfusion suppression by nearly 50%. This reflects the increasing back pressure due to the orthostatic compression of the splenic vein this way underscoring the haemodynamic significance of this compression and explaining the gradually increasing left flank pain in the patient while standing due to increasing tissue turgor of the spleen.

This way the so far undescribed mechanism of left flank pain could be elucidated.

2.

Unbearable hammering stabbing pain developing after 30 minutes of standing in the left lower thorax and left upper lumbar region due to an orthostatic compression of the splenic vein by the superior mesentric artery

I report here on the second observation of a 23-year-old female patient who developed unbearable hammering and stabbing pain in the left upper lumbar region and in the lower thorax after the correction of a May Thurner syndrome and a so-called Nutcracker syndrome. The decompression of the left renal vein and the left common iliac vein had been successful. The related symptoms nearly completely disappeared.

Because the new pain was different from the preoperative pain, it was suspected that a complication of the surgery might be responsible for the excruciating pain that prevented the patient from doing housework, shopping, or living a normal life.

However, the decompression of the left iliac vein with the normalization of the drainage of the pelvic hemispheres.

In horizontal posture the splenic vein is uncompressed, the flow velocity 32 cm/s. The mesentric artery is not visible hence out of this imaging plane due to its large distance from the splenic vein.

The reason for this pain is a posture-dependent severe compression of the splenic vein by the liver from above and the curved origin of the superior mesenteric artery from below.

While standing the splenic vein is squeezed inbetween the downsinking liver and the superior mesentric artery

While standing the flow velocity upstream the compression site of the splenic vein is 12 cm/s

While standing the flow at the compression of the splenic vein changes dramatically. It becomes pulsatile and accelerated to 119 cm/s!

Lying supine, a normal drainage of the spleen be demonstrated but after assuming an upright posture a circumscribed compression of the splenic vein developed with a pulsatile and strong flow acceleration at the compression site.

Precise placement of the measurement is necessary to demonstrate the flow changes.
Position 1: compression 121 cm/s
Position 2: 1 cm downstream the compression 53 cm/s

It is especially remarkable that symptoms developed not in synchronicity with the changes of the flow pattern in the splenic vein.

While lying the splenic vein has neither contact to the celiac trunk nor the superior mesentric artery (sagittal view)

The compression of the splenic vein occurred within 1 minute after standing upright. The diminution of the vessel’s diameter and the extent of the flow acceleration especially with the rhythmic interruption of the flow was impressive despite the patient was still without pain.

It took about 30 minutes for the symptoms to develop. Then a sharp, stabbing, rhythmically hammering pain in the area of the spleen was reported within the left lower thorax and the left paralumbar region radiating into the left flank.

Then the patient again assumed a supine posture and the symptoms immediately disappeared within 1 minute.

Again, the asynchronicity  to the of the pain development and the significant delay of the normalization of the perfusion pattern within the splenic vein was a surprising observation.

The accelerated flow within the splenic vein persisted for about 5 minutes despite immediate cessation of pain. Then the flow returned to a bandlike slow venous flow pattern.

My explanation for this observation is the following:

The pain while standing is a result of the increasing congestion of the spleen producing strong pain due to stretching of the splenic capsule. The pain mechanism is similar to that in splenic torsion  – which is also causing an acute venous congestion which may even produce a hemorrhagic infarction if the congestions lasts too long.

Some freely accessible illustrative papers on splenic torsion, which exerts its clinical symptoms – mainly acute left flank pain  due to a torsion-induced congestion of the splenic vein – can be found here:

Splenic torsion, a challenging diagnosis: Case report and review of literature

Splenic torsion: a rare cause of abdominal pain

Splenic torsion: a case report

A posture dependent splenic vein compression was not described in the medical literature so far to the best of my knowledge – these are thus the first descriptions of this excruciating disease.

Only a few reports describe splenic vein compressions due to hepatomegaly or splenic or celiac artery aneurysms.

It is remarkable that splenic torsion is more frequently found in women than in men and more in patients with connective-tissue disorders. This is exactly the same population that is prone to abdominal vascular compression syndromes.

The flow acceleration receives its full extent only after the maximum possible distension of the spleen. The spleen is then full of blood and the distended capsule allows no further enlargement of the spleen. The intrasplenic pressure then reaches its climax. This is producing an extreme flow acceleration at the compression site.  So it takes a while until the well- known large reserve pooling capacity of this organ is exhausted. But this time span is exactly the time from the beginning of the orthostatic splenic vein compression till the beginning of the left flank pain. The spleen reacts similar to an inflated rubber balloon after opening the inlet – which is the splenic vein in this analogy.

Only after exhaustion of the capacity the tension of the splenic capsule reaches its painful limit.

The patient’s description that the pain was hammering is perfectly explained by the rhythmic flow interruption of the splenic venous drainage due to the intermittent total compression by the superior mesenteric artery.