Comment to: Pre-operative determination of anatomic variations of the small saphenous vein for varicose vein surgery by three-dimensional computed tomography venography by Kim SY, Park EA, Shin YC, Min SI, Lee W, Ha J, Kim SJ, Min SK. Phlebology 2012;27:235-41.

Stefano Ricci

Abstract

Short saphenous vein (SSV) surgery is more challenging due to higher recurrence and complication rates than great saphenous vein (GSV) surgery. The main reason for that is the presence of many anatomic variations in SSV anatomy and the close proximity of the vein with adjacent nerves in the somewhat crowded popliteal fossa. Accurate anatomic knowledge about the varicose veins (VV) and neural topography is necessary to prevent nerve damage during surgery. Duplex ultrasound (DUS) imaging is the gold standard investigation for VV, but has limitations such as operator-dependent variable results, a time-consuming procedure, possible omission of perforators in unusual locations and a difficulty in the evaluation of pelvic vessels. Three-dimensional computed tomography venography (3D-CTV) cannot replace DUS, but can provide additional powerful 3D images. The exact anatomy of the individual patient can be evaluated before surgery, so that the surgery can be performed with full knowledge of the patient specific anatomy and hemodynamic. This may contribute to minimizing complications and recurrence after VV surgery with SSV reflux. From January 2005 until December 2007 a total of 120 limbs in 103 patients with SSV insufficiency confirmed by duplex underwent conventional operations of high ligation, segmental stripping and varicosectomy. On the basis of the classification of venous disease (CEAP), clinical grades were C2 in 106 cases (88.3%), C3 in 13 (10.8%) and C4 in 1 (0.9%). Duplex ultrasound and 3D-CTV were performed pre-operatively mostly on the same day and were analyzed retrospectively for this study by two expert radiologists. Saphenous veins and perforators larger than 1 mm were detected and marked on computed tomography (CT) volume-rendering images. The presence of reflux in axial veins and the marked perforators was evaluated by duplex. Surgeons reviewed this information pre-operatively and CT volume-rendering images were used as road maps during the operation. Short saphenous vein terminated to popliteal vein (PV) in 115 limbs (95.8%) with saphenopopliteal junction (SPJ) in the popliteal fossa, to the veins above the popliteal fossa without SPJ in 5 limbs (4.2%) – including femoral vein in 2, great saphenous vein in 2 and deep femoral vein in 1. Thigh extension (TE) of SSV was encountered in 74 limbs (64.4%), SSV and gastrocnemial vein (GNV) drained to PV separately (100 limbs, 87%), as a common channel which drained to PV (15 limbs, 13%). The neural topographic situation of the SSV was analyzed at the level of the gastrocnemius muscle origin. Routine post-operative DUS performed 4–6 weeks after surgery found no residual reflux. During six months of follow-up, two transient sural nerve neuralgia resolved spontaneously. Sural nerve location could not be evaluated by CTV because of the small diameter of the nerve and many variations of the nerve division. Possible disadvantages of CTV, such as renal dysfunction, allergic reaction to radio contrast, radiation injury and additional cost can be a problem. However, a careful patient selection and a meticulous protocol can minimize these complications.



Comment by Stefano Ricci

Three-dimensional computed tomography venography offers exiting images of VV anatomy. However, the question is when this tool should be used. DUS may provide the same type of information (SSV termination, SSV morphology, the relationship between SSV and GNV, and that between SSV and adjacent nerves) as CT. Yet, it also provides functional aspects that are not retrievable with CT. Furthermore, DUS is performed on standing subjects, to whom static (compression/release, Valsalva) and dynamic maneuvers (oscillation, Parana) may be applied to study the hemodynamic behaviour of flow. On the contrary, CT is done on laying subjects. Patently enough, DUS examination needs certain (although basic) training, even though such training is currently requested to all who want to deal with VV treatments. Conversely, CT – apart from yielding nice images – has plenty of drawbacks, as described by the same authors. These images may surely be useful in some limited cases (malformations, recurrences, anatomical complicated variations), but are not necessary in more than 95% of them. Moreover, a patient selection is suggest by the Authors, but no criteria for such selection is given. Finally, concerning sural nerve location, while CTV is not able to evaluate these nerves, DUS with adequate probes is able to show the nervous structures.1


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References

1. Ricci S, Moro L, Antonelli Incalzi R. Ultrasound Imaging of the sural nerve: ultrasound anatomy and rationale for investigation. Eur J Vasc Endovasc Surg 2010;39:636-41.[CrossRef][PubMed]

 

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