Free gracilis end-to-side microanastomosis to a peronea arteria magna: a case report

A 55-year-old Caucasian male cyclist was brought to a major trauma center by ambulance after he was involved in an alleged unwitnessed collision with a heavy goods vehicle. He was found on the road at 05:30, time of impact unknown.

The individual was right-handed and employed as a fish filleter. He was fully ambulant and independent for activities of daily living prior to admission. A bicycle or motorcycle were his main means of transportation. He lived with his wife in a house with internal stairs and external steps, a downstairs toilet, and upstairs bedroom. A family history of alcohol misuse was noted but no other familial medical conditions recorded.

Past medical history included diverticulosis, right bundle branch block, and a past closed right distal third tibia and fibula fracture 27 years earlier, which was successfully managed non-surgically. No regular medications were taken prior to admission and the gentleman was a non-smoker who consumed no alcohol.

In the ambulance, he was given intravenous co-amoxiclav 1.2 g, tranexamic acid 1 g, ketamine 2 mg/kg, paracetamol 1 g, ondansetron 4 mg, and intramuscular (IM) tetanus toxoid. On arrival, he was hypotensive with a blood pressure of 71/41 mmHg, a heart rate of 60 beats per minute, hypothermic with a temperature of 33.9 °C, respiratory rate of 20 breaths per minute, and oxygen saturation of 99% on high-flow oxygen by non-rebreather mask.

Physical examination revealed cold, pale skin, both centrally and peripherally, dry mucous membranes, and his airway was clear with no obvious chest injury. There was bleeding from both ankle wounds and a right arm wound. Clinical deformity of both ankles and the right upper limb were present. He had subtotal degloving of the right sole from the plantar heel pad to mid-foot, with a closed medial malleolar fracture suitable for non-surgical management (Fig. 1a–b). On the left, there was an anteromedial wound over the distal third of the leg overlying a Weber C bimalleolar fracture (Fig. 1c). The right foot was initially hypoperfused (capillary refill time of 3–4 seconds, no palpable pulses), and the left foot well perfused (capillary refill time < 2 seconds, palpable dorsalis pedis pulse). His neurological evaluation identified a Glasgow Coma Scale of 15/15 and he was noted to be agitated. He had abrasions to his scalp and bruising to his forehead and right cheek. He was diagnosed with a right humerus fracture and radial nerve palsy, however no other sensory deficit was identified.

Computed tomography (CT) of the head, neck, chest, abdomen, and pelvis excluded other injuries. The right foot perfusion improved to a capillary refill time of 2 seconds after fluid resuscitation with two units of packed red cells and 1.5 L crystalloids and application of plaster of Paris splints to both ankles and right upper limb. Laboratory findings after transfusion showed anemia and leukocytosis consistent with blood loss and acute phase response. Hemoglobin was 121 g/L (135–175 g/L), white blood cell count 26.4 × 10⁹/L (4.0–11.0 × 10⁹/L), and platelet count 289 × 10⁹/L (150–400 × 10⁹/L). Serum biochemical indices and liver function tests were within reference range, except creatinine 125 µmol/L (65–114 µmol/L), bicarbonate 19 mmol/L (24–32 mmol/L), and albumin 30 g/L (36–48 g/L). Coagulation parameters (prothrombin and activated partial thromboplastin time) were within reference ranges. Urinalysis at admission was not recorded.

Debridement of the lower limb wounds and application of Hoffman external fixation (Stryker, Kalamazoo, MI, USA) to the left lower limb fracture was performed the following day, together with internal fixation of the humeral shaft fracture. The left ankle wound was 8 × 5 cm, communicated directly with the tibial fracture, and was associated with localized subcutaneous degloving towards the Achilles tendon. A topical negative pressure wound therapy (TNPWT) dressing was applied to this Gustilo–Anderson Grade 3b open fracture after debridement.

There was multi-planar degloving of the right heel pad involving 60% of the plantar skin (25 × 27 cm), which appeared perfused (capillary refill 2 seconds), communicating with additional degloving of the dorsal foot where there was a 5 cm diameter wound on the dorsolateral foot and a 6 × 7 cm wound on the central dorsum of foot with exposed extensor tendons. Extensive contamination of the foot degloving was debrided. The right foot wound edges were loosely apposed with sutures, and TNPWT was applied enclosing the foot.

Following admission, intravenous co-amoxiclav 1.2 g TDS was continued for 10 days, and intravenous metronidazole 500 mg BD was added on days 7–10 because of positive culture of mixed coliforms and fecal microorganisms from right heel wound swabs.

Analgesia comprised paracetamol 1 g QDS, oxycodone modified release 10 mg BD, supplemented with oxycodone immediate release 5–10 mg PRN. Dalteparin 5000 units subcutaneously OD was administered as thromboprophylaxis. An oral (PO) phosphate supplement was administered for 14 days for hypophosphatemia commencing on the third day of admission.

A CT angiogram of the lower limbs was performed to assess the arterial contributions to both feet. This identified an unexpected finding of a left peronea arteria magna (PAM) (Fig. 2a–c), and normal three vessel arterial flow to the right foot. Percutaneous angiography was recommended to fully evaluate left foot perfusion, which revealed that the PAM supplied the plantar arch. The anterior and posterior tibial arteries were hypoplastic or aplastic and appeared to provide no contribution to the plantar arch (Fig. 3a and b).

Preoperative patient counseling was informed by the CT angiogram and angiography findings, which helped us to specifically explain the risks of acute ischemia or steal phenomenon following end-to-side microanastomosis to the only artery to the left foot.

A combined orthoplastic reconstruction of the left ankle was performed, with removal of the external fixator and internal fixation of the bimalleolar fracture and free gracilis flap reconstruction harvested from the right thigh. A palpable and Doppler-audible dorsalis pedis artery was present at the start of the case, but no signal was present proximal to the anterior ankle. During the preparation of the left ankle recipient vessels, it was noted that the PAM passed from lateral to medial across the posterior distal tibia in the coronal plane. It was accompanied by two venae comitantes on the medial and lateral aspect of the artery that were each of similar caliber to the artery itself. The diameter of the PAM at the posterior tibia just proximal to the medial malleolus was similar in size to that expected of a posterior tibial artery. Intraoperative microvascular clamping of the artery resulted in foot hypoperfusion, with skin pallor and capillary refill time of 4 seconds, however this gradually improved to 3 seconds with resolution of pallor over approximately 1 hour, despite the clamp being applied. An end-to-side anastomosis was performed using a circular arteriotomy of the PAM, and one venous anastomosis end-to-end with the medial vena comitans to the PAM. Two days after reconstruction, capillary refill returned to 1–2 seconds in the left foot, and the dorsalis pedis artery remained palpable. The healed left gracilis flap at 8 weeks is shown in Fig. 4a and b. Following microsurgical reconstruction, aspirin 75 mg OD and lansoprazole 30 mg OD were given for 6 weeks.

Postoperatively, he developed a cough and Klebsiella aerogenes was isolated from sputum. On the advice of the microbiology team, he was commenced on a single dose of gentamicin 480 mg intravenously, plus piperacillin and tazobactam 4.5 g intravenously TDS for 7 days and co-trimoxazole 960 mg intravenously BD for 6 weeks. The right foot plantar degloved flap subsequently developed full thickness necrosis, with 50% necrosis of abductor hallucis, and exposed calcaneum with a thick malodorous exudate. Escherichia coli was isolated from tissue cultures, urine, and blood cultures, with additional Clostridium novyi and Enterococcus hirae identified from right heel tissue cultures. Right foot debridement was performed, and topical vancomycin and tobramycin in a calcium sulphate carrier (Stimulan®, Biocomposites Ltd., Keele, England) was applied to the exposed bone, in conjunction with the above intravenous antibiotic therapy.

Following the above debridement, when the wounds were macroscopically clean, a final debridement and simultaneous chimeric free musculocutaneous latissimus dorsi-serratus fascial flap was performed for right foot and ankle reconstruction, via end-to-side microanastomosis to the right posterior tibial artery. The 8 week outcome is presented (Fig. 5a–d). The patient developed COVID-19 related pneumonia 2 weeks after his second free flap operation (positive COVID-19 nucleic acid polymerase chain reaction test from nasopharyngeal swab), from which he made a full recovery after an extended inpatient stay.

Other medications include laxatives, which were required for the second and third weeks of admission, namely Movicol (Norgine, Harefield, UK) 2 sachets PO TDS, senna 15 mg PO nocte (every night), followed by lactulose 15 ml PO BD until discharge. Zopiclone 3.75 mg PO PRN nocte was prescribed during the third inpatient month, and a protein nutritional supplement was commenced in the last 3 weeks of admission and continued after discharge.

Intensive rehabilitation and physiotherapy continued after the 3 months of inpatient hospital stay. The right lower limb flap developed skin graft loss and recurrent soft tissue infections with Pseudomonas aeruginosa at 4 months after surgery, requiring readmission and debridement. The radial nerve palsy had partially recovered at 6 months with active wrist extension present; nerve conduction studies and electromyography noted findings consistent with a severe axonotmesis lesion at the upper humerus level with features suggestive of reinnervation. The left ankle flap had a good outcome at 7 months with no evidence of deep infection (Fig. 6a–d).