Why Partial First Ray Amputations In Patients With Diabetic Neuropathy Do Not Work

Author(s): 
Sara L. Borkosky, DPM, AACFAS, and Thomas S. Roukis, DPM, PhD, FACFAS

Diabetes mellitus with peripheral sensory neuropathy and the associated increased risk of ulceration continue to be growing issues in today’s society.1-28 Peak ambulatory forces occur about the first ray, creating a cycle of stresses, tissue buildup and eventual breakdown.2 Conservative therapies often fail due to an inability to offload the wound properly, poor pedal hygiene and inadequate distal blood flow. Many of these patients eventually progress to require an amputation.3

   Adherence to basic principles requires the removal of all necrotic, non-viable tissue and will result in a functional, durable, residual foot. Preserving the length and integrity of the remaining structures routinely leads to a partial first ray amputation. However, this level of amputation often leads to frequent failures and the need for further intervention, causing us to question the durability and predictability of the partial first ray amputation.

What Two Studies On Partial First Ray Amputation Reveal

We conducted two studies, the first being a systematic review of the world literature to determine the re-amputation rate following a partial first ray amputation in this specific population.4 Of the 435 partial first ray amputations, the incidence of re-amputation was 19.8 percent (86/435). The end stage, most proximal level of amputations following a partial first ray amputation were: an additional digit amputation in 32 patients (37 percent); transmetatarsal amputation in 28 patients (34 percent); and below-knee amputation in 25 patients (29 percent).

   The results of this study therefore demonstrate that one of five patients having any version of a partial first ray amputation will eventually require more proximal re-amputation.4 We concluded that, according to the world literature completely from diabetic foot care centers of excellence, partial first ray amputation for patients with diabetes and peripheral sensory neuropathy does not represent a durable, functional or predictable foot-sparing amputation.

   Unfortunately, most practitioners are not employed at diabetic foot care centers of excellence. Accordingly, we believe that the incidence of re-amputation for this patient population is likely higher when community-based practitioners perform the amputations. Additionally, little data was available for comparison in regard to morbidity and mortality associated with this procedure.

   Therefore, in order to investigate these concerns further, we conducted a retrospective review focusing on patients with diabetes mellitus and peripheral sensory neuropathy who had a partial first ray amputation at the Gundersen Health System over an 11-year period.5 This is a level II trauma, community-based and tertiary referral center in the Midwest.

   In this second study, we evaluated a total of 7,487 cases from January 2001 to December 2011 for possible inclusion in the study.5 Of these, 59 patients met the inclusion criteria of diabetes mellitus with peripheral sensory neuropathy and a primary partial first ray amputation. We defined the partial first ray amputation as occurring distal to the first metatarsocuneiform joint, including the phalanges of the hallux, with primary closure at the time of surgery. For this study, we excluded patients if they had additional digital amputation, required vascular intervention or were diagnosed with non-reconstructable ischemic disease. We collected retrospective chart review information to acquire a better understanding of the morbidity and mortality of this procedure in a high-risk population. At the time of the final chart review, 28 of the patients were deceased at a mean of 34.6 months post-initial amputation.

Comments

This is an interesting paper. However, I do take exception to the notion that sub-total 1st ray amputations "don't work." Of course, they work. The issue is highly patient dependent. Certainly, further amputations or revisions do occur and statistically this may exceed what would be acceptable in most scientific reviews.

However, two issues come to mind.

1) What would a "center of excellence" propose? TMA, Chopart disarticulation, or higher amputations to obviate any further foot procedures? (This is assuming that amputation of something is absolutely necessary. I work at two wound centers and certainly SOME recommended amputations can be avoided at times.)

2) Not all the patients fall into the study criteria. For example, my patient in the hospital right now had a sub-total first ray amputation with the 2nd toe disarticulation at the 2nd MTPJ due to overt gangrene, abscess and cellulitis, with a history of severe cardiomyopathy, CKD, s/p ilio-tib bypass, and poorly controlled type 2 diabetes without primary closure of the surgical site. He may have a year to live.

So the final point is sometimes a sub-total first ray amputation DOES work for the particular patient in mind. That's my problem with the title of the paper in that others may reject the necessary procedure.

Please e-mail me any desired response but I do appreciate your efforts in this study.

Fraternally,

Neil H Hecht, DPM, FACFAS, FACFAO

I currently am the assistant director of a wound care center/limb salvage program. I am called upon to perform partial first ray amputations on a regular basis. I would tend to believe that the destabilization of the forefoot and midfoot after the procedure leads to recurrence and re-amputation at a higher level.

For this reason, I have began "beaming" the remainder of the medial column. I have found initially this prevents the destabilization and further surgical intervention on the first ray and medial column. The patients are followed with a custom insole to help protect the area. Any additional procedures on the lesser digits can be performed assuming appropriate revascularization has been done if needed.

To date, this seems to result in a higher patient satisfaction than a primary transmetatarsal amputation

Cheers

Ira Weiner, DPM

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