Addressing A Gangrenous Fifth Digit

In a case study involving a gangrenous fifth digit in an 88-year-old patient, this author discusses the use of a minimum incision ray resection and fillet of toe flap after appropriate revascularization to facilitate more expeditious healing and limb salvage.

An 88-year-old male presented to the emergency room with dry gangrene of the fifth digit of the right foot, which occurred approximately three weeks after the patient sustained trauma to this area.

   The patient and his family reported a similar presentation 18 months prior on the left foot. The patient presented to a different facility for treatment of his left foot. Surgeons performed a common femoral artery endarterectomy, superficial femoral artery angioplasty and open amputation of the fifth digit. Healing of the fifth digit amputation site was complicated by delayed wound healing and subsequent osteomyelitis necessitating partial resection of the fifth metatarsal, which the surgeons left open to heal. Physicians employed negative pressure wound therapy and used advanced wound care products for approximately six months until final healing occurred. Healing in this manner resulted in a hypertrophic scar, which had the tendency for callus formation.

   Upon presenting to the emergency room for the right foot, the patient was afebrile, had normal vital signs and was metabolically stable. The patient reported no known drug allergies. His past medical history consisted of hypertension, hyperlipidemia and neuralgia. The past surgical history consisted of the aforementioned left lower extremity procedures, back surgery and eye surgery. The patient’s current medications were simvastatin (Zocor, Merck) 20 mg at night, amlodipine (Norvasc, Pfizer) 30 mg daily, gabapentin (Neurontin, Pfizer) 800 mg three times daily, lisinopril 20 mg daily, hydrochlorothiazide (Dyazide) 10 mg daily and tramadol (Ultram, Janssen Pharmaceuticals) 50 mg daily. The patient denied use of tobacco or alcohol and lived in a single story home.

   Examination of the patient’s right foot revealed dry gangrene of the entire fifth digit. The peroneal artery had a monophasic signal and the dorsalis pedis and posterior tibial arteries were non-audible with Doppler exam.

   The patient was admitted. After an arteriogram of the right lower extremity, the patient underwent a femoral to popliteal bypass with a polytetrafluoroethylene synthetic graft. The day after the vascular procedure, surgeons performed a disarticulation amputation of the fifth digit at the level of the metatarsophalangeal joint, a minimum incision fifth ray resection and a fillet flap of the fourth toe to allow for closure of the amputation site.

   The patient remained non-weightbearing for four weeks and transitioned to full weightbearing for short distances only in a postoperative shoe for an additional two weeks. The patient was fully healed and returned to his preoperative ambulatory status at six weeks postoperatively in extra depth shoes with custom insoles. Physicians modified the left insole to limit callus formation along the hypertrophic scar on the left foot. The patient has remained fully healed 12 months postoperatively.

Comparing Treatment Outcomes Of The Left And Right Feet

The goal of any limb salvage procedure is to maintain a functional limb for ambulation. Surgical planning should also include selection of a procedure, which will most likely result in rapid healing with minimal risk for complications.

   In the case presented here, the patient presented each time with critical limb ischemia and dry gangrene of the fifth digit. Each time, the patient underwent appropriate procedures for revascularization prior to the partial foot amputation. For the left foot, the patient had two surgical interventions, negative pressure wound therapy and the use of advanced skin substitutes for a total of six months prior to complete healing.

   Although a formal cost analysis did not occur, we can assume the total cost of care for the left foot was several thousands of dollars in addition to the patient’s personal expense for travel and the emotional expense in dealing with a chronic wound. Additionally, the resultant scar was prone to pressure and callus formation, causing it to be at risk for future breakdown.

   Contrast this with the treatment of the patient’s right foot. Surgeons employed a partial fifth ray resection and fillet flap of the fourth toe to allow for tension free closure of the amputation site as the index procedure on the foot. Although the patient lost the fourth toe, he was fully healed with minimal loss of function and was ambulatory without restriction at six weeks postoperatively.

   Minimum ray resection allowed for complete removal of the necrotic digit, facilitated reduced tension on the resultant soft tissue defect and preserved vascularity to the soft tissue envelope due to the limited dissection and disruption of the intermetatarsal space in which the vessels travel.1 Use of the fillet flap of the fourth toe provided durable and readily available coverage of the amputation site. This did not result in excess “bulk” at the distal foot, covered the remaining bone and minimized the potential for prolonged healing and further amputation.2,3

What The Literature Reveals

Küntscher and colleagues reported on 11 patients and cases in which surgeons utilized fillet of toe flaps to cover defects secondary to trauma, tumor excision, ulceration, osteomyelitis, gangrene and burns.2 With one flap, there was total necrosis secondary to progressive gangrene, which necessitated a more proximal amputation. In another case, the authors noted partial necrosis with a flap and subsequent wound healing via secondary intention.2 Use of fillet of toe flaps resulted in successful healing in the remaining nine patients.

   Roukis reported on 13 patients who had 17 ray resections utilizing the minimum incision technique.1,3,4 Seven patients were without complications, one patient had delayed healing due to non-adherence, four patients underwent more proximal amputation due to progressive gangrene and there was one death.1

In Conclusion

The use of minimum incision ray resections and fillet of toe flaps can result in expeditious limb salvage, which is paramount in the case of limb salvage secondary to critical limb ischemia. These techniques allow for rapid primary closure and limit disruption of the soft tissues and vascularity of the foot. Furthermore, these techniques limit the potential for compromised skin and soft tissue should an additional procedure be necessary, and can limit the loss of function of the residual foot. The primary factor resulting in failure of these procedures appears to be compromised circulation to the foot.1,2 One should take this into consideration prior to selection of the definitive surgical procedure when treating critical limb ischemia.

   Dr. Schade is the Chief of the Limb Preservation Service and Director of the Complex Lower Extremity Surgery and Research Fellowship at Madigan Healthcare System in Tacoma, Wash. She is an Associate of the American College of Foot and Ankle Surgeons.

References
1. Roukis TS. Minimum-incision metatarsal ray resection: an observational case series. J Foot Ankle Surg. 2010; 49(1):52-54, 2010.
2. Küntscher MV, Erdmann D, Homann H-H, Steinau H-U, Levin SL, Germann G. The concept of fillet flaps: classification, indications, and analysis of their clinical value. Plas Recon Surg. 2001; 108(4):885-896.
3. Öznur A, Ozer HO. Ray amputation with limited incision: clinical tip. Foot Ankle Int. 2006; 27(5):382.
4. Öznur A, Roukis TS. Minimum-incision ray resection. Clin Pod Med Surg. 2008; 25(4):609-622.