Anatomical basis of a safe mini-invasive technique for lengthening of the anterior gastrocnemius aponeurosis

Abstract

Background: The surgical procedure itself of lengthening the gastrocnemius muscle aponeurosis is performed to treat multiple musculoskeletal, neurological and metabolical pathologies related to a gastro-soleus unit contracture such as plantar fasciitis, Achilles tendinopathy, metatarsalgia, cerebral palsy, or diabetic foot ulcerations. Therefore, the aim of our research was to prove the effectiveness and safety of a new ultrasound-guided surgery-technique for the lengthening of the anterior gastrocnemius muscle aponeurosis, the "GIAR"- technique: the gastrocnemius-intramuscular aponeurosis release.

Methods and results: An ultrasound-guided surgical GIAR on ten fresh-frozen specimens (10 donors, 8 male, 2 females, 5 left and 5 right) was performed. Exclusion criteria of the donated bodies to science were BMI above 35 (impaired ultrasound echogenicity), signs of traumas in the ankle and crural region, a history of ankle or foot ischemic vascular disorder, surgery or space-occupying mass lesions. The surgical procedures were performed by two podiatric surgeons with more than 6 years of experience in ultrasound-guided procedures. The anterior gastrocnemius muscle aponeurosis was entirely transected in 10 over 10 specimens, with a mean portal length of 2 mm (± 1 mm). The mean gain at the ankle joint ROM after the GIAR was 7.9° (± 1.1°). No damages of important anatomical structures could be found.

Conclusion: Results of this study indicate that our novel ultrasound-guided surgery for the lengthening of the anterior gastrocnemius muscle aponeurosis (GIAR) might be an effective and safe procedure.

Keywords: Aponeurosis; Gastrocnemius muscle; Minimally invasive; Ultrasound.

Fig. 1

Instruments for the minimally invasive ultrasound-guided procedure. High-resolution ultrasound; 18-gauge needle; 50 cc syringe; V-shape straight curette; hook knife (Acufex®), analogic goniometer, surgical pen

Fig. 2

a, b US-guided pre-surgical mapping for ultrasound-guided GIAR. a (yellow line)… mapping of the course of saphenous nerve along the crural region; (Blue line)…mapping of the course of great saphenous vein along the crural region; (white asterisk)…the needle is inserted through the surgical portal immediately dorsal to the course of the great saphenous vein, superficial at the interval between the anterior gastrocnemius aponeurosis and the soleus muscle. b (white dotted lines)…gastrocnemius muscle bellies representation at the dorsal aspect of the crural region. (white asterisk)…the hook knifes, ventral one introduced through the surgical portal at the interval between the soleus and gastrocnemius muscle aponeurosis (up to the most lateral aspect), the other one positioned at the dorsal aspect of the skin of the crural region as a demonstration for the correct positioning of the first one. (Red dot)… represents the distal transection point. (green dotted line)…represents the transection at the anterior gastrocnemius muscle aponeurosis (color figure online)

Fig. 3

a–d US-guided surgical routine for GIAR. 3a (needle)…18 g needle seen through an in-plane approach in the long axis hydrodissecting proximal to the conjoint tendon, the virtual anatomical space in between the anterior gastrocnemius muscle aponeurosis, ventrally to both gastrocnemius heads from medial to lateral and the soleus aponeurosis and its underlying muscle belly (SM) dorsally, both seen in the short axis. b from the medial portal, it could be seen the V shape straight courette (V-shape) dorsal to the 18 g needle (needle) both seen through an in-plane approach in the long axis at the hydrodissected interval in between the anterior gastrocnemius muscle aponeurosis and the medial head of its muscle belly (GM) and soleus aponeurosis and its underlying muscle belly (SM) both seen in the short axis. c from the medial portal, it can be seen the hook knife through an in plane approach in the long axis at the hydrodissected interval in between the anterior gastrocnemius muscle aponeurosis and medial head of its muscle belly (GM) and the soleus aponeurosis and its underlying muscle belly (SM) both seen in the short axis. d After hook knife transection it can be seen the gap at the anterior gastrocnemius muscle aponeurosis (AGMA) and the buttoned probe in between the gap through an out of plane approach in the short axis at the hydrodissected interval in between the anterior gastrocnemius muscle aponeurosis and medial head of its muscle belly (GM) and soleus aponeurosis and its underlying muscle belly (SM) both seen in the long axis (color figure online)

Fig. 4

a, b Anatomical dissections for proof after US-guided GIAR technique. a (AGMA)… transected anterior gastrocnemius muscle aponeurosis; (PT)… transected plantaris tendon. b (AGMA)… transected anterior gastrocnemius muscle aponeurosis; (PT)… transected plantaris tendon; (GIAR)… gastrocnemius intramuscular aponeurosis recession; (CF)… crural fascia; (SN)… preserved sural nerve; (GSV)… great saphenous vein.

Fig. 5

a, b The gain at the ankle joint range-of-motion (ROM) after our US-guided GIAR-technique. (black lines)…the line drawn on the distal crural region marks the shaft of the fibular bone, the black line drawn on the foot marks the shaft of the fifth metatarsal bone; a pre-surgery, clinical evaluation for equinus deformity due to gastrocemius muscle contracture. b post-surgery, one can see the gain in extension range of motion at the ankle joint (color figure online)