Vascular anatomy and surgical approach in oblique lateral interbody fusion at lumbosacral transitional vertebrae

BACKGROUND

Oblique lateral interbody fusion (OLIF) at lumbosacral junction is typically performed on the central window between the bifurcations of iliac vessels. However, the central window of lumbosacral transitional vertebrae (LSTVs) is usually obstructed by the iliocaval venous structures. We aimed to describe the vascular anatomy and surgical approach in OLIF at LSTVs compared with those in OLIF at typical L5-S1 junction.

METHODS

Sixty-eight consecutive patients who underwent OLIF at lumbosacral junction were included. Of these, 31 patients had LSTVs and 37 patients had typical L5-S1 junction. The position of the iliocaval junction and the configuration of the left common iliac vein were compared using the preoperative CT and MR images of the lumbar spine. The surgical approach and intraoperative vascular findings were analyzed.

RESULTS

Almost 70% of LSTVs had the iliocaval junction at low or very low position. Mobilization of left common iliac vein for central window was potentially difficult in almost 74% of OLIF at LSTVs while it was not required or was potentially easy in almost 80% of OLIF at typical L5-S1. Vascular injury was identified in 2 (6.5%) patients with OLIF at LSTVs and in 3 (8.1%) patients with OLIF at typical L5-S1 junction (P = 0.904).

CONCLUSIONS

In our series, OLIF at LSTVs was performed through lateral window in 93.5% of the cases. Preoperative evaluation of the iliocaval junction using CT/MR of lumbar spine was reliable and valid in the determination of OLIF approach at lumbosacral junction.

May-Thurner syndrome, a diagnosis to consider in young males with no risk factors: a case report and review of the literature

Background

May–Thurner syndrome is an anatomical condition characterized by compression of the left common iliac vein by the right common iliac artery, causing venous outflow obstruction. It is an uncommon cause of deep vein thrombosis and is more prevalent among women. This paper highlights the importance of considering May–Thurner syndrome in young males without risk factors presenting with left lower limb pain, as endovascular treatment may be required.

Case presentation

A 23 year-old Caucasian male presented with a 1-week history of left lower limb pain, edema, and pallor. He was found to have an unprovoked deep vein thrombosis on Doppler ultrasound involving the left fibular, soleus, gastrocnemius, popliteal, femoral, common femoral, and external iliac veins. A heparin infusion was commenced as the initial treatment for deep vein thrombosis. Further investigation with computer tomography pulmonary angiogram and computer tomography venography of the abdomen and pelvis showed bilateral pulmonary emboli and left common iliac vein compression with left common, internal, and external iliac vein thrombosis. He was diagnosed with May–Thurner syndrome despite having no risk factors. A retrievable Cook Celect Platinum inferior vena cava filter was placed, and thrombus of the left common femoral, external, and common iliac veins was treated successfully with AngioJet thrombectomy, thrombolysis using 200,000 units of urokinase, angioplasty and stenting using two Cook Zilver Vena venous self-expanding stents. Therapeutic enoxaparin was commenced on discharge. His filter was removed after 10 weeks. Hematological follow-up 4 months later showed an overall negative thrombophilia screen, and anticoagulation was switched to apixaban. He has had no recurrent thrombosis.

Conclusions

Clinicians should have a low threshold to investigate for May-Thurner syndrome in patients with left lower limb venous thrombotic events regardless of risk factors, as endovascular treatment may be required to minimize the long-term sequelae of deep vein thrombosis. Duplex ultrasound can be used initially for diagnosis, and computer tomography venography used subsequently if the common iliac vein is not visualized on ultrasound. Endovascular treatment is preferred over anticoagulation alone, especially in otherwise fit patients presenting early, the aim being to reduce the chances of chronic venous hypertension in the lower limb.

A median sacral artery anterior to the iliocaval junction: a case report-anatomical considerations and clinical relevance for spine surgery

BACKGROUND AND IMPORTANCE

The median sacral artery (MSA) is a relatively small vessel that always arises from the posterior, terminal part of the infrarenal aorta. In most cases, the MSA runs behind the iliocaval junction. Here, we describe a very rare case of an MSA running in front of this junction.

CASE REPORT

During a human cadaveric dissection of the retroperitoneal area, we unexpectedly observed that the MSA passed in front of the left common iliac vein.

CONCLUSION

The anatomy of the MSA has been extensively described and variations are quite rare. On the basis of this specific case, knowledge of the anatomic interactions between the MSA and other lumbar retroperitoneal vessels may help to avoid potential complications during surgery.

Preoperative evaluation of left common iliac vein in oblique lateral interbody fusion at L5-S1. Eur Spine J. 2017;26:2797-2803. [PMID: 28643127 DOI: 10.1007/s00586-017-5176-6]

PURPOSE

Oblique lateral interbody fusion (OLIF) L5-S1 is essentially to perform an anterior lumbar interbody fusion (ALIF) in the lateral position. Because the surgical procedures are performed "obliquely" over the left common iliac vein (LCIV), ensuring that the vein is protected which is particularly important. We aimed to evaluate the configuration of LCIV and its risk of mobilization during anterior approach at L5-S1 segment.

METHODS

This study involved 65 consecutive patients who underwent anterior lumbar fusion (ALIF, n = 39; OLIF, n = 26) at the L5-S1 segment. Three independent examiners evaluated the configuration of the LCIV at the L5-S1 disc on axial magnetic resonance images of the lumbar spine. The LCIV was categorized into three types according to the difficulty of mobilization: type I (no requirement for mobilization; LCIV runs laterally for more than two-thirds of the length of the left side of the L5-S1 disc), type II (easy mobilization; LCIV obstructs the L5-S1 disc space, but the perivascular adipose tissue is present under the LCIV), and type III (potentially difficult mobilization; no perivascular adipose tissue under the LCIV). The patient records were reviewed for vascular complications.

RESULTS

There were 21 men and 44 women in this study, with a mean age of 63.4 years (range 19-83 years). Type I LCIV configuration was found in 32 (49.2%) patients, type II in 18 (27.7%), and type III in 15 (23.1%). There were 7 (10.8%) patients with LCIV injury (type I, n = 0; type II, n = 2; type III, n = 5) (P = 0.003). Intraobserver reliability for the LCIV classification ranged from substantial to excellent, and interobserver reliability ranged from moderate to excellent.

CONCLUSIONS

Preoperative evaluation for anterior approach to the L5-S1 segment should take account of the LCIV position, as well as the difficulty of its mobilization. The type III LCIV configuration showed a high rate of vascular injury.