The sural nerve: Sonographic anatomy, variability and relation to the small saphenous vein in the setting of endovenous thermal ablation.

Background Neurological complications are well documented in association with both surgical stripping or disconnection and thermal ablation of the small saphenous vein. The sural nerve (medial sural cutaneous nerve) is most vulnerable due to its close relationship to the small saphenous vein. Objective This is a cross-sectional observational study of the sonographic anatomy of 115 Australian patients to determine the course of the sural nerve and its relationship to the small saphenous vein, and to identify its relevance in the thermal ablation of the small saphenous vein. Method Sonographic mapping of the right sural nerve was performed with a Philips L12.5 and Sonosite 10.5 MHz ultrasound machine on 115 patients. The sural nerve was traced proximally from the level of the lateral malleolus to the popliteal fossa in order to measure its distance from the small saphenous vein at four reference points in the lower leg. Results A total of 115 patients were studied (females 82, males 33). The sural nerve was identified in 100% of patients; 64 patients (55.7%) showed usual sural nerve anatomy, while 51 patients (44.3%) demonstrated a range of anatomical variations, including the sural nerve becoming epifascial at a higher point than usual. Conclusion The sural nerve was identifiable on duplex ultrasound in 100% of cases. Classic anatomical relations and the perceived protection of the sural nerve conferred by the deep fascia of the upper calf are unreliable. Preoperative strategies can help to approach and protect the sural nerve in the endovenous ablation setting.

Preoperative chemical component relaxation using Botulinum toxin A: enabling laparoscopic repair of complex ventral hernia.

BACKGROUND: Repair of complex ventral hernia can be very challenging for surgeons. Closure of large defects can have serious pathophysiological consequences. Botulinum toxin A (BTA) has recently been described to provide flaccid paralysis to abdominal muscles prior to surgery, facilitating closure and repair. METHODS: This was a prospective observational study of 32 patients who underwent ultrasound-guided injections of BTA to the lateral abdominal wall muscles prior to elective repair of complex ventral hernia between January 2013 and December 2015. Serial non-contrast abdominal CT imaging was performed to measure changes in fascial defect size, abdominal wall muscle length and thickness. All hernias were repaired laparoscopically or laparoscopic-assisted with placement of intra-peritoneal mesh. RESULTS: Thirty-two patients received BTA injections which were well tolerated with no complications. A comparison of baseline (preBTA) CT imaging with postBTA imaging demonstrated an increase in mean baseline abdominal wall length from 16.4 to 20.4 cm per side (p < 0.0001), which translates to a gain in mean transverse length of the unstretched anterolateral abdominal wall muscles of 4.0 cm/side (range 0-11.7 cm/side). Fascial closure was achieved in all cases, with no instances of raised intra-abdominal pressures or its sequelae, and there have been no hernia recurrences to date. CONCLUSIONS: Preoperative BTA injection to the muscles of the anterolateral abdominal wall is a safe and effective technique for the preoperative preparation of patients prior to laparoscopic mesh repair of complex ventral hernia. This technique elongates and thins the contracted and retracted musculature, enabling closure of large defects.

Hydrodisplacement of sural nerve for safety and efficacy of endovenous thermal ablation for small saphenous vein incompetence.

Background Endovenous radio frequency ablation for small saphenous vein incompetence by and large appears to be superior and safer than conventional open surgery. Small saphenous vein ablation from approximately mid-calf to the point proximally where the small saphenous vein dives into the popliteal fossa is considered to be safe, as the sural nerve is in most cases separated from this segment of the small saphenous vein by the deep fascia. The outcome of the distal incompetent small saphenous vein remains unclear. Efficacy of the endovenous radio frequency ablation can be enhanced by increasing the length of the ablatable small saphenous vein segment. Methodology To optimise endovenous radio frequency ablation outcome, the distal small saphenous vein may be made amenable to ablation if safety of the sural nerve can be assured. The sural nerve was successfully located using duplex ultrasound in 100% of our cohort in this study. The standard entry point for venous access was just above the lateral malleolus. After introduction of the introducer sheath, the radio frequency catheter was advanced proximally; the sural nerve was displaced from the small saphenous vein by approximately 1 cm with the administration of tumescent anaesthesia ( hydrodisplacement). A total of 118 patients underwent extended endovenous radio frequency ablation of 124 incompetent small saphenous vein trunks using the method described. Results Successful extended ablation of the small saphenous vein was achieved in 100% of cases and it was confirmed by duplex scanning at one and six weeks. Two neurological events were recorded during the study: 1. One patient with temporary foot drop lasting for less than 6 h with complete recovery. 2. A second patient with a sural nerve sensory deficit reported by the patient at day 2-3, which remains current at six weeks. Conclusions Extended endovenous radio frequency ablation of the small saphenous vein to optimise length of the ablatable vein segment is feasible with careful identification and hydrodisplacement of the sural nerve. This method is shown to be associated with fewer neurological complications than other methods reported in the literature.