Distal Symes amputation of the 5th toe – A case series highlighting treatment of tip of toe pathologies including neuropathic ulceration with chronic osteomyelitis, gangrene, phalangeal fracture nonunion, and adducto varus hammertoe with Lister's corn

The 5th toe is prone to diabetes related tip of toe ulceration with secondary osteomyelitis of the distal or middle phalangies. Tip of 5th toe gangrene may also develop which is often embolic in origin and may have associated localized osteomyelitis. These conditions are often treated with partial 5th ray amputation, especially when acute or chronic infection develops. We commonly perform distal Symes amputation of the 5th toe when the problem is isolated to the tip of the toe, but this procedure is not generally associated with the 5th toe. Distal Symes amputation is also indicated for other tip of 5th toe pathologies including painful underlapping 5th toe, distal phalanx fracture associated with nonunion or crush injury, painful Lister's corn, bone spur of the distal phalanx, hemangioma of the distal phalanx, and nail pathologies requiring aggressive permanent nail removal.

Distal Symes amputation of the 5th toe is a versatile procedure that can be performed in the clinic setting minor procedure room for most patients. Complete removal of the nail bed and distal phalanx provides a plantar flap of tissue that is suitable for resurfacing of the tip of the toe and provides a cosmetically acceptable result despite loss of some digital length. The procedure effectively releases the long flexor contracture which further reduces irritation associated with contracture deformity. Gangrene or ulceration needs to be isolated to the tip of the toe for the procedure to be effective and we sometimes remove the middle phalanx if needed for better flap coverage or if osteomyelitis is suspected. Synostosis of the DIPJ is another reason to resect bone back to the PIPJ. We present a case series of four patients who underwent distal Symes amputation of the 5th toe to highlight specific patient selection criteria and demonstrate the simple surgical technique.

We utilize a modified fish mouth incision that involves advancement of a plantar flap to cover the soft tissue defect present after resecting the nail, nail bed and bone. This is similar to the classic technique used for distal Symes amputation of the hallux and central toes that we previously described.^{,  ,}  The dorsal arm of the incision is made transversely over the proximal or distal interphalangeal joint and the dorsal tissues provide no significant contribution to coverage at the time of closure. The plantar incision is designed to create a plantar flap that will be advanced dorsally (Fig. 1a,b). The tip of toe lesion (ulcer, gangrene, or callus), toenail, nail matrix, and distal phalanx are then removed (Fig. 1c). The distal phalanx is sectioned for culture and pathologic evaluation if bone biopsy is desired. Bone removal allows laxity within the soft tissues for minimal tension on the plantar flap (Fig. 1d). The middle phalanx may be removed in the presence of DIPJ synostosis or if desired to provide better flap mobility. Suspected osteomyelitis of the middle phalanx is another reason to remove the middle phalanx but preserving bone length provides a better cosmetic result. The digital tourniquet is then removed to assess vascularity to the flap. Hemostasis is achieved sparingly with electrocautery since hematoma is rare, as there is no dead space present after closure. The plantar flap is then advanced to resurface the end of the toe with viable soft tissue (Fig. 1e). A dry, sterile dressing is then applied. Sutures are left in place for about 2–4 weeks.

Distal Symes amputation of the 5th toe is a viable treatment option for a variety of chronic tip of 5th toe pathologies for which more traditional surgical procedures may be ineffective or overly aggressive. Amputation of the entire 5th toe for wound and infection concerns is usually accompanied by partial resection of the 5th metatarsal due to fear of shoes rubbing on the 5th metatarsal head after isolated metatarsal phalangeal disarticulation. Preservation of a portion of the 5th toe is desirable when possible but indications for tip of toe amputations are narrow as described below. Nail pathology of the 5th toe is less amenable to sharp or chemical matrixectomy due to the small nature of the nail bed compared to the other toes yet the 5th toe is very prone to painful nail deformity. The distal Symes procedure is a very effective method to permanently remove a problematic 5th toenail. Additionally, traditional hammertoe procedures may not resolve pain associated with an underlapping 5th toe or painful bone spurs of the distal phalanx.

The biggest factor with regard to patient selection is that the condition needs to be very isolated to the tip of the 5th toe which rules out many patients with ulceration, gangrene, abscess, or osteomyelitis. The soft tissues also need to be healthy enough to create a viable plantar tissue flap which rules out another large group of diabetic and vascular patients presenting with 5th toe conditions. There is less concern for soft tissue coverage or healing potential in patients with bone deformity or nail problems but many patients will reject the idea of partial toe amputation as an elective treatment option. In this case series, we present a variety of distal tip of 5th toe pathologies that benefited from distal Symes amputation. This included neuropathic ulceration with associated with osteomyelitis of the distal phalanx, distal tip of toe gangrene, painful fracture nonunion, and a symptomatic bone spur associated with nail pathology and Lister's corn. These are some of the main indications for the procedure for which we have found high patient satisfaction.

The distal Symes procedure allows bone biopsy, confirmation of clean margin, excision of skin lesions, and immediate flap closure in cases involving ulceration, gangrene and suspected infection. In the treatment of diabetic foot infections, successful surgical management is dependent on adequate resection of nonviable tissue and subsequent antibiotic therapy. Without adequate management, these patients are at a high risk for a more proximal foot or leg infection. Ramsey and colleagues studied 8905 patients with diabetes for 3 years and 514 developed a foot ulcer. 15% of those patients with a foot ulcer developed osteomyelitis and 15.6% required an amputation. In cases of osteomyelitis, obtaining a clean margin of bone for confirmation of surgical cure of the bone infection has implications for the antibiotic treatment course. The infectious Disease Society guidelines suggest prescribing antibiotic therapy for a short duration (2–5 days) in cases where successful surgical resection of the bone infection is achieved. However, if there is a persistent bone infection, they suggest prolonged (≥4 weeks) antibiotic treatment. Boffeli and colleagues studied 48 patients with tip of toe ulcerations who underwent a distal Symes amputation in a clinic setting. All patients had bone cultures and proximal margin biopsies sent for pathology. Of the 48 patients, 73% had positive bone cultures, 69% had positive pathologic findings demonstrating osteomyelitis, and 100% had clean margins.

5th toe biomechanical deformities such as hammertoe contracture, digit quinti varus, and underlapping 5th toes are typically treated with PIPJ arthroplasty which may or may not resolve tip of toe pain around the nail bed, distal phalanx and medial or lateral skin folds. The distal Symes procedure directly addresses bone prominence on the medial and lateral edges of the nail plate, eliminates a painful thick nail, releases long flexor contracture, and removes the tip of the toe which commonly underlaps the 4^th toe. Medial pinch callus is another common condition associated with 5th toe underlap which can be effectively resolved with distal Symes amputation due to the ability to shift the redundant tissue out from under the 4th toe.

This case series is intended to provide surgeons with a brief overview of conditions that are appropriate for distal Symes amputation of the 5th toe. Shortcomings include the retrospective nature of the review and short term follow up. Case inclusion was designed to highlight patient selection and surgical technique since this topic is not well represented in the medical literature. Further study is needed to fully assess outcomes and patient satisfaction.

The authors declare that informed patient consent was taken from all the patients.

T.J. Boffeli has ownership in Surgical Design Innovations, Park Ridge, IL.