The arterial communication between the gastrocnemius muscle heads: a fresh cadaveric study and clinical implications

Evolution and Diversity of Medial Sural Artery Perforator Flap for Hand Reconstruction

The free medial sural artery perforator (MSAP) flap is a recently popularized flap. It has evolved from a composite myocutaneous flap to a pedicled perforator flap for lower limb reconstruction. It is also a versatile free perforator flap for extremity and head and neck reconstruction. The diversity of the flap designs with options for harvest of non-vascularized grafts enhances the versatility for hand and upper limb reconstruction. The adjunctive use of endoscopy and indocyanine green fluorescence imaging studies can assist and demystify the flap anatomy. The authors present their experience using free MSAP flaps for complex mutilated hand and upper extremity reconstruction.

A Cadaveric Study on Perforator Anatomy of the Medial Sural Artery Perforator Flap

Background  The medial sural artery perforator (MSAP) flap was described by Cavadas et al in 2001. The aim of this study was to analyze the flap characteristics in the regional population and was planned as a cadaveric dissection study. Methods  Thirty-three legs of fresh cadavers were studied for perforator characteristics, length, and origin of pedicle and skin paddle thickness. Observations were documented and analyzed. Results  Seventeen right legs (51.5%) and sixteen left legs (48.5%) were studied. Twenty-five pedicles originated from popliteal artery (86.2%) and four (13.8%) from the common sural trunk. No perforators were seen in four legs. The mean number of perforators is 2 (0-6). The mean distance of perforator from midpoint of popliteal fossa was 10.7 cm (8-13 cm) and from posterior midline it was 3.2 cm. The mean size of the perforator was 1.1 ± 0.8 mm (0.8-1.5 mm). The mean pedicle length was 9.3 ± 1.3 cm. The mean flap thickness was 4.3 ± 0.7 mm (3.0-5.5 mm). There was no correlation for flap or perforator characteristics with side of leg. Conclusion  This study concludes that MSAP is a good flap in terms of perforator characteristics, pedicle length, and flap thickness, when a medium sized thin flap with long pedicle is needed. The location of perforator on calf varies in different population. Being a perforator flap, anatomical variability is common and should be thought of while choosing this flap.

Sural Artery as a Recipient Vessel for Free Flaps

Introduction The axial vessels like the anterior and posterior tibial emerge as the first choice of recipient vessels, in free flaps for lower limb trauma. When the defects are located more proximally in the leg, the deeper course of the axial vessels makes the dissection more tedious. Alternative vessels like the descending genicular, medial genicular, and distal end of the descending branch of the lateral circumflex femoral can be used for an end-to-end anastomosis, well away from the zone of trauma.

The objective of this study was to define the indications and technique of the use of the sural vessels as the recipient pedicle for proximal and middle third leg defects.

Patients and Methods For the period 2006 to 2022, 18 leg defects following road traffic accidents were covered with latissimus dorsi muscle flap using sural vessels as the recipient pedicle.

Results Among 18 patients, 8 patients had defect in proximal third, 8 had a combined defect in proximal and middle third leg, and 2 had defect in middle third leg. Two patients developed arterial thrombosis and one patient had venous thrombosis for which re-exploration was performed. Two flaps were lost and sixteen had successful wound coverage.

Conclusion The sural vessels as recipient pedicle are easier to access and can be considered as a reliable option for free flaps in limb defects of proximal and middle third leg. Using the submuscular part of the vessel ensures a better distal reach of the flap.

The Medial Sural Artery Perforator Flap: A Historical Trek from Ignominious to “Workhorse”

Rather than just another “review,” this is intended to be an “overview” of the entire subject of the medial sural artery perforator (MSAP) flap as has been presented in the reconstructive literature from its inception in 2001 until the present, with any exceptions not purposefully overlooked. Unfortunately, the pertinent anatomy of the MSAP flap is always anomalous like most other perforator flaps, and perhaps even more variable. No schematic exists to facilitate the identification of a dominant musculocutaneous perforator about which to design the flap, so some adjunctive technology may be highly valuable for this task. However, if a relatively thin free flap is desirable for a small or moderate sized defect that requires a long pedicle with larger caliber vessels, the MSAP flap deserves consideration. Indeed, for many, this has replaced the radial forearm flap such as for partial tongue reconstruction. Most consider the donor site deformity, even if only a conspicuous scar on the calf, to be a contraindication. Yet certainly if used as a local flap for the knee, popliteal fossa, or proximal leg, or as a free flap for the ipsilateral lower extremity where a significant recipient site deformity already exists, can anyone really object that this is not a legitimate indication? As with any perforator flap, advantages and disadvantages exist, which must be carefully perused before a decision to use the MSAP flap is made. Perhaps not a “workhorse” flap for general use throughout the body, the MSAP flap in general may often be a valuable alternative.

Analysis of Vascular Anatomy in Inferiorly Based Gastrocnemius Muscle Flaps in Japanese Individuals Using a Cadaver Study

Background:

Inferiorly based gastrocnemius muscle flaps have been successfully used to cover soft tissue defects of the middle third of the leg. This is done especially in older patients or patients with major complications where operative time should be limited. We aimed to determine the gastrocnemius muscle length that can be safely used for preparing inferiorly based muscle flaps.

Methods:

We performed angiographies and dissection to investigate the numbers and distribution of the communicating arterial branches between the medial and lateral heads of the gastrocnemius muscle, and the perforating arterial branches of the medial sural artery from the soleus to the gastrocnemius muscles on 18 legs of preserved cadavers.

Results:

The lengths of the gastrocnemius heads were approximately 10 cm, and the communicating arterial branches of the gastrocnemius muscle also were located at approximately 10 cm from the gastrocnemius head. The perforating arterial branches from the soleus muscle to the gastrocnemius muscle were also located at approximately 10 cm from the gastrocnemius head.

Conclusions:

Communicating arterial branches of the gastrocnemius muscle were found in all cadavers. To the best of our knowledge, no other study has focused on investigating the perforating arterial branches that supply the gastrocnemius from the soleus muscle. Our study indicates that the entire gastrocnemius muscle can be safely used in reconstruction surgeries.

An early complication in the donor site of the medial sural artery perforator flap: necrosis of the medial head of gastrocnemius

The relatively new medial sural artery perforator flap is increasingly being used for reconstruction. However, muscle necrosis of the medial head of gastrocnemius after MSAP flap harvest is a previously unnoticed early complication of the donor site. We present two cases of MSAP flap reconstruction that developed this early complication.

Gastrocnemius Myocutaneous Flap: A Versatile Option to Cover the Defect of Upper and Middle Third Leg

BACKGROUND

Large soft tissue leg defect involving upper and middle third remains a therapeutic challenge. The objective of this study was to evaluate the effectiveness and versatility gastrocnemius myocutaneous flap cover for post traumatic large defect of upper and middle third of leg.

METHODS

This prospective study was conducted from January 2015 to January 2017 on 25 consecutive cases of post-traumatic upper and middle third leg defect who were treated with gastrocnemius myocutaneous flap and the functional and aesthetic outcome were evaluated.

RESULTS

There was no case of complete flap failure. Partial skin necrosis occurred in 2 patients (8%). There was no postoperative hematoma while mild discharge was seen in only 4(16%) patients. With regard to the donor site morbidity, no functional deformity was seen in follow up period. The procedure was found to be reliable, technically easy and aesthetically acceptable.

CONCLUSION

Post-traumatic large defects of leg extending in upper and middle third were easily covered with the help of regional gastrocnemius myocutaneous flap with excellent outcome and aesthetically acceptable coverage of skin without any major complications or long term morbidity.

Cadaveric study using radio-opaque contrast to determine arterial communication between the two bellies of gastrocnemius muscles

INTRODUCTION

Gastrocnemius muscle is a workhorse flap to cover upper third tibial defects but has a limitation in covering middle one-third tibial defects. The inferiorly based hemi gastrocnemius muscle flap can be useful for reconstruction of the middle third of the leg. The arterial communication between the gastrocnemius muscle heads has been demonstrated, the consistent location, however, was not studied in large specimens.

MATERIALS AND METHODS

This study was conducted on sixty specimens of gastrocnemius muscles harvested from thirty fresh cadavers to determine arterial communication between two heads of gastrocnemius muscle using radio-opaque contrast with future application of taking one head of muscle distally based for coverage of middle third defect of tibia. A total of 60 specimens were obtained from thirty fresh cadavers. In thirty specimens, medial sural artery ligated and divided and 20 ml iohexol (350) given through popliteal artery. In remaining thirty specimens lateral sural artery ligated and divided and 20 ml iohexol (350) given through popliteal artery. Digital X-rays of gastrocnemius muscle specimens were taken, and collaterals between two bellies in lower half were noted and the distance of collaterals from the muscles top edge was also noted.

RESULTS

We found the communications between both bellies of the gastrocnemius muscle in all specimens in both legs. The mean distance of communications from the upper edge of the medial belly was 15.88 cm and from upper edge of the lateral belly was 14.72 cm in the right leg, respectively. The mean distance of communications from upper edge of the medial belly was 16.01 cm and from upper edge of the lateral belly was 13.78 cm in the left leg. The distal communications between gastrocnemius bellies were not constant in their location, but all the connections were present in distal 3.79 cm of raphe.

CONCLUSION

This study supports the future application of inferior-based hemigastrocnemius muscles flap to cover defects of middle third leg. When distally based hemigastrocnemius flap is planned roughly 1/3(rd) of distal attachment or distal 3.79 cm of connection between raphe should be maintained to preserve the vascular communications between the two bellies.

The medial sural artery as recipient vessel and the impact on the medial gastrocnemius

Microsurgical free tissue transfer is a valuable technique for the reconstruction of soft-tissue defects around the knee, and the medial sural artery (MSA) is an ideal recipient vessel for anastomosis. Previously, the vessel has been described as the dominant supply to the medial gastrocnemius, but no research has addressed the subsequent effect to the muscle after interruption of MSA. The volume of the postoperative medial gastrocnemius of 4 patients treated with free flap reconstruction using MSA as recipient, was assessed clinically and using magnetic resonance imaging, with muscle function assessed using a patient questionnaire, and measurement of ankle torque with concurrent electromyography. Magnetic resonance imaging volume assessment revealed the postoperative medial head of gastrocnemius proportional to its synergist of separate blood supply, the lateral gastrocnemius and functional assessment suggest little difference between limbs such that the MSA should be used with confidence as recipient vessel for free flap reconstruction of soft-tissue defects around the knee.

The medial sural artery perforator flap: a versatile donor site for hand reconstruction

BACKGROUND

The challenge of modern hand reconstruction goes beyond simple coverage. Thanks to the advances of microsurgery, there are ever-improving standards of functional and esthetic outcomes in hand reconstruction. The versatile donor site of the medial sural artery perforator flap can fulfill this purpose.

MATERIALS

Between June 2006 and October 2008, we used free medial sural artery perforator flaps for hand reconstruction in 14 cases. The sites of reconstruction included digits (n=7), dorsal hand (n=3), palmar hand (n=2), and wrist (n=2). Associated tendon and nerve defects were found in five patients. The plantaris tendon (n=4), split Achilles tendon (n=1), saphenous nerve (n=1), and sural nerve (n=1) were harvested for reconstructive purpose from the same donor site in this series.

RESULTS

The proximal perforator of the medial sural artery emerged 8 cm to 13 cm from the midpoint of the popliteal crease, correlating with the axis of the medial sural artery. Twelve flaps were raised with a single perforator. One flap failed because of perioperative vasospasm. The donor defect could be closed without skin grafts when the flap width was <6 cm.

CONCLUSION

The free medial sural artery perforator flap transfer is appropriate for small- to medium-sized hand defect reconstruction. The donor site not only supplies a thin fasciocutaneous flap but also provides the option to harvest a segment of tendon or nerve graft through the same incision for composite tissue reconstruction in a single stage.

Anatomical basis of the medial sural artery perforator flap in Asians

Forty-four lower limbs preserved in formaldehyde from cadavers of adult Asians were used. In all specimens 1-5 perforating branches from the medial sural artery were found. No perforators were found higher than 5 cm or lower than 17.5 cm from the popliteal crease. In the most common place (16/44, 36%) in which 2 perforators were found, the proximal one was a mean of 9.6 cm away from the popliteal crease, and the distant one 12.8 cm. All perforators were in an area between 0.5 cm and 4.5 cm from the midline of the gastrocnemius muscles. Because of the differences in the length of the muscle belly, the distribution of perforators may differ between white people and Asians. It should be safe to raise this flap in Asians, because the anatomical comparison of the perforators of the medial sural artery between Asians and white people is now clear.

Plantar reconstruction using the medial sural artery perforator free flap

Free flaps are usually required rather than local flaps for large plantar defects, due to a lack of locally available tissue. The medial sural artery perforator free flap, recently introduced clinically by several authors, is a noticeable option for soft tissue coverage, but it has still not been widely used for the reconstruction of various large plantar defects. Between 2005 and 2007, medial sural artery perforator free flaps were used to reconstruct soft tissue defects in plantar areas in 11 patients at our institute. Patient ages ranged from 10 to 68 years (mean, 43 years), and follow-up periods ranged from 7 to 22 months (mean, 13 months). Flap sizes ranged from 10 to 14 cm in length and from 5 to 7 cm in width. Flaps survived in all patients. Marginal loss over the distal flap region was noted in 1 patient, and this was treated successfully with a subsequent split-thickness skin graft. In another one case, venous insufficiency developed, but salvage was successful with leech application. Long-term follow-up showed good flap durability with a protective sensation. The medial sural artery perforator flap provides sufficient durability for weight-bearing areas, even though it is a thin cutaneous flap. The authors recommend that this flap be considered as a reliable alternative for the reconstruction of large plantar defects.

The segmental gastrocnemius muscle flap: anatomical study and clinical applications

BACKGROUND

The versatility of the gastrocnemius muscle for reconstruction of defects in the knee region from the upper third of the calf to the lower third of the thigh is well known. Possible limitations of this flap include difficulties in covering multiple separate wounds in the same area as well as contour deformity because of the flap bulkiness. The findings in this study extend the versatility of the gastrocnemius muscle flap by splitting each head into two segments allowing for the closure of multiple defects.

METHODS

Studied was the vascular anatomy of 15 fresh cadaveric lower extremities. Contrast material was injected into the sural artery and this showed the bifurcation of the pedicle in the upper third of the muscle. A constant intramuscular vascular pattern represented by two main longitudinal branches permitted the safe division of each head. Based on these anatomic studies, segmentation was performed of the gastrocnemius muscle flap in 29 patients. In 13 cases were used, one or two muscle segments and in 16 cases, three muscle segments were transposed.

RESULTS

All of the flaps survived. Minor complications, such as wound dehiscence, cellulitis, or hematoma, were encountered in seven patients. Except for one patient with persistent drainage from osteomyelitic bone, all the wounds closed successfully.

CONCLUSIONS

The authors report the safe splitting of the distal gastrocnemius muscle in 29 patients based on vascular anatomic studies. The advantages of gastrocnemius segmentation include the possibility of covering multiple defects with less contour deformity.

The sural artery perforator flap for coverage of defects of the knee and tibia

We reconstructed four knee and lower leg defects using the sural artery perforator flap between 2000 and 2003, and describe them here. The sural artery perforator flap can save the gastrocnemius muscle, its motor nerve, deep fascia, lesser saphenous vein, and sural nerve with no functional loss. Intramuscular dissection of the perforator achieves increased length of the pedicle compared with a conventional gastrocnemius myocutaneous flap. The flap is thin, and either the medial or lateral sural artery may be used. The flap is suitable in selected cases for regional reconstruction around the knee and upper half of the lower leg as a pedicled flap.

Gastrocnemius muscle flap of both heads on a single vascular pedicle

We present a case of a muscle flap of both heads of gastrocnemius on a single vascular pedicle for reconstruction of a tibial defect. The flap was based on the medial sural vessels alone. The vascular supply to the lateral head was achieved through the anastomotic vessels along the gastrocnemial raphe.

Neurovascular Stalk of the Superficial Sural Flap: Human Fetus Anatomical Study

BACKGROUND

The neurovascular stalk of the superficial sural flap, which is the most frequently used, is composed of the lesser saphenous vein, the sural nerve, and the median superficial sural artery. However, it has many variations. This is very important for its application in the reconstruction of soft-tissue defects. The aim of the authors' research was to detect the presence of the superficial sural blood vessels and to investigate their relationships with the sural nerve and the lesser saphenous vein.

METHODS

The study group consisted of 42 fetal lower extremities. Fetuses were fixed in 10% formalin and their blood vessels were injected with Micropaque solution (barium sulfate).

RESULTS

The median superficial sural artery was detected in 83.3 percent of the cases, whereas the sural nerve and lesser saphenous vein were detected in all cases. The median superficial sural artery was located lateral to the medial cutaneous sural nerve and sural nerve, whereas the lesser saphenous vein was located medially.

CONCLUSIONS

All three superficial sural arteries (medial, median, and lateral) were detected in fetuses with different gestational ages. The median superficial sural artery was the most frequently detected one and had the constant relationship with the other elements of the neurovascular stalk of the superficial sural arteries.

The Medial Sural Artery Perforators

We performed an anatomic study on 20 fresh lower limbs. Resin was injected in the popliteal artery. Medial sural artery perforator flaps were sculptured according to anatomic markings. On average, length of flaps was 12.9 cm, width was 7.9 cm; all 38 perforators were musculocutaneous: 1 perforator was always found (on average, 1.9 per flap). All perforators gathered between 7 and 18 cm from the popliteal crease; 34.2% of perforators arose on the midline of the medial head of gastrocnemius muscle; before entering the fascia, the perforator artery diameter was on average 0.5 mm. Two configurations of the intramuscular course of perforators were found. Sixty-six percent of perforators originated from the lateral branch of the medial sural artery, 34% from the medial one. These results improve the anatomic knowledge of the medial posterior calf region and allow us to describe a convenient plan to make flap sculpturing easier.

Sequential Use of a True Perforator Flap and Its Corresponding Muscle Flap

A true perforator flap completely spares the underlying muscle that was previously required as essentially a passive carrier of that musculocutaneous unit. Thus, a perforator flap and its related muscle can now be simultaneously transferred as independent but conjoint flaps based on the same source pedicle, or sometimes also in a metachronous fashion if the requisite source vessels remain intact. The latter principle proved feasible after failure of 2 medial sural perforator flaps that were subsequently successfully replaced by a conventional medial gastrocnemius muscle flap. At least theoretically, depending on the extent of intramuscular dissection, another advantage that can be applied to all perforator flaps is that the muscle can be held in reserve for sequential use as necessary.

The medial sural artery perforator free flap

The medial sural artery supplies the medial gastrocnemius muscle and sends perforating branches to the skin. The possible use of these musculocutaneous perforators as the source of a perforator-based free flap was investigated in cadavers. Ten legs were dissected, and the topography of significant perforating musculocutaneous vessels on both the medial and the lateral gastrocnemius muscles was recorded. A mean of 2.2 perforators (range, 1 to 4) was noted over the medial gastrocnemius muscle, whereas in only 20 percent of the specimens was a perforator of moderate size noted over the lateral gastrocnemius muscle. The perforating vessels from the medial sural artery clustered about 9 to 18 cm from the popliteal crease. When two perforators were present (the most frequent case), the perforators were located at a mean of 11.8 cm (range, 8.5 to 15 cm) and 17 cm (range, 15 to 19 cm) from the popliteal crease. A series of six successful clinical cases is reported, including five free flaps and one pedicled flap for ipsilateral lower-leg and foot reconstruction. The dissection is somewhat tedious, but the vascular pedicle can be considerably long and of suitable caliber. Donor-site morbidity was minimal because the muscle was not included in the flap. Although the present series is short, it seems that the medial sural artery perforator flap can be a useful flap for free and pedicled transfer in lower-limb reconstruction.

The inferiorly based gastrocnemius muscle flap: anatomic aspects

The arterial communication between the gastrocnemius muscle heads through their lowest anastomotic arteriole bundle alone was examined in specimens from 14 fresh cadavers. In 3 specimens, the larger vessels in close vicinity to the lowest vessels were preserved as well. Distinct communication between the arterial networks of the heads was demonstrated in all cases after injecting dyes through both sural arteries or into the lateral sural artery and the lowest anastomotic arteriole in 11 and 3 specimens, respectively. Therefore, it seems that one head can be adequately supplied from the contralateral one through their lowest anastomotic arteriole(s); nevertheless, the location of this vessel varies significantly and cannot be detected preoperatively. Measurements demonstrated that although this vessel is not found at a constant level, it is invariably detected in the lower third of the medial gastrocnemius head's length and, in 93 percent of cases, in the lower fourth. Thus, rough preoperative planning becomes feasible. Given that the venous communication between the heads has been documented as well, the authors think that an inferiorly based flap of the medial gastrocnemius head for defects of the middle third of the tibia might be both reliable and applicable; however, for reasons of safety, the muscle heads should remain attached along their lower third.

The venous communication between the gastrocnemius muscle heads

This investigation establishes the venous communication between the gastrocnemius muscle heads. Fourteen fresh (with the exception of one) cadaveric specimens were examined. Anastomotic veins were dissected along the raphe after perfusion of each muscle with 0.1 % methylene blue solution. A distally based musculocutaneous perforating vein of the medial head was the site of perfusion in 13 specimens, whereas one specimen received injection through the accompanying vein of the medial sural cutaneous nerve. Additional perfusion of dye from different sites was required in two specimens. Communicating veins were dissected in all 14 muscles. Direct anastomotic veins were detected in eight specimens; whereas in six the accompanying vein of the medial sural cutaneous nerve that had been included proved to be the intermediate pathway of venous communication between the muscle heads. Obstructive valves were encountered in most cases; nevertheless anastomotic veins were always recognized. The role of valves and the clinical implications are discussed.