Amputations and Prostheses



Fig. 17.1
Standard Burgess posterior flap



In combat-related lower extremity injuries however, it is difficult to rely on only one learned technique. Rarely is the surgeon able to perform a standard BKA. None of the proposed techniques take into consideration the extent of soft tissue injuries seen in combat-related injuries which poses a grave limitation to the flap design. The surgeon frequently has to work with what is left. Local “flaps of opportunity” are considered if standard flaps cannot be fashioned (Fig. 17.2). The option of free flaps and skin grafts also subsists.

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Fig. 17.2
(a, b) Flaps of opportunity . Used when soft tissue injury is severe limiting standard flap design. Closed suction drainage are preferred, but in limited resource conflict hospitals a Penrose drain may be used




Surgical Technique


Typically, the treatment principles are the same for all levels of amputation. The goal is to remove all dead tissue and residual foreign material. The operation must be conducted in the least time possible. When feasible, control of bleeding is maintained through continued use of pneumatic tourniquets [34]. Early aggressive debridement, usually within the first 2 h, is performed with a skin incision made as distal as possible through the skin and fascia, in an attempt to conserve as much tissue as possible. The purpose of the incisions is to allow full exposure of the affected tissue [2, 14, 34]. Copious irrigation must be done to help remove all bacteria and foreign bodies. Overall, normal saline was recommended for irrigation with limited use of additives. Low-pressure irrigation is preferred to high-pressure jet lavage [35].

The cornerstone of war surgery is to remove all the nonviable tissue. The viability of tissue is to be assessed in the operating theater, with the aid of the four Cs: color, consistency, contractility, and capillary bleeding when cut [36, 37]. All nonviable soft tissue of the fat, fascia, and muscles should be debrided. Next the bone must be addressed. As mentioned above, maximal bone length should be achieved. Contaminated ends need to be curettaged to remove foreign bodies. All small bone fragments should also be removed as they are devoid of blood supply and will pose an additional risk of infection. Overzealous debridement and removal of tissue is irreversible and can cause loss of function, thus moderation is recommended.

Wounds are usually dressed open, with readdressing the stump in the coming 1 or 2 days [14]. Primary closure greatly increases the likelihood of infection [2, 38]. In the less likely cases where the patient arrives within 6 h of the original injury, and if indeed the wound is adequately and meticulously debrided, then it is acceptable to close the wound primarily with carefully examining the wound at least once daily [39].


Intermediate Phase of Management


All of the lifesaving resuscitative surgery is usually performed at the battlefield scene, in what is known as combat support hospitals. The maximal length of stay there is intended to be 3 days. After the amputation is performed and the patient stabilized, transfer is done to the next level of care, a more advanced and sophisticated medical facility. There, the patient will be tended to further management.


Uncomplicated Amputations



Wound Care


It is currently recommended that closure of wounds in combat environments be delayed because of the high contamination rate, especially when patient presentation is delayed [35]. Early primary wound closure causes high rates of serious wound infection eventually requiring much more extensive debridement and sometimes leading to patient demise [40].

While waiting for closure, the stump is dressed with a sterile, clean, dry, absorbent dressing to minimize ongoing contamination. The traditional saline-soaked gauze dressing, covered by dry gauze, is more than sufficient for the stump wound (Fig. 17.3). The use of silver-impregnated dressings, topical antibiotics, or medical honey creams has not been proven to prevent infections, and are therefore not a superior choice [4144]. The dressing does not have to be occlusive, for there is little evidence showing a reduce in infection rate, faster healing, or being associated with less pain [42].

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Fig. 17.3
Clean above-knee amputation stump dressed with wet saline gauze

The use of negative pressure therapy (NPT) has become the standard of care in many facilities. Data is conflicting about the effectiveness of NPT, with the potential benefits and harms in healing wounds by secondary intention remain largely uncertain [45]. It must be clear that the purpose of the NPT is not to help close the wound completely, but instead it is used as a bridge for definite closure. A one- to ten-day reduction is achieved in the time needed to prepare the wound for secondary closure surgery [46] (Fig. 17.4).

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Fig. 17.4
Amputation stump after 2 weeks of application of vacuum dressing


Stump Closure


Repeat debridement if necessary, which is to be done at 48 h followed by wound dressing. It is expected to close the wound by the fourth or fifth day after the initial amputation. This scenario is based on the assumption that the patient is both young and healthy, the wound is completely clean, and there is no evidence of infection or necrotic tissue [35, 40, 47].

There remains to be many options regarding the method to be used to close the open stump. The general principle is that the skin must be closed without tension. A robust soft tissue envelope is also critically important. Adequate padding is necessary for the residual limb to tolerate the high impact and shear forces associated with regular prosthesis wear [48]. Looking at the reconstructive ladder, local wound care, primary closure, skin grafting, local skin flaps, pedicled flaps, and free flaps are all important components for definitive soft tissue coverage [49, 50]. Sometimes the surgeon is inclined to use more than one of the aforementioned techniques to close the stump (Fig. 17.5). The mainstay in amputation stump closure remains to be local flaps.

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Fig. 17.5
Below-knee amputation stump closed by a posterior vascularized flap with an anterior split thickness skin graft

The issue that arises is that in combat-related injuries , there is significant loss of soft tissue, which poses a limiting factor in proper wound closure. To adequately close the stump, it becomes necessary to shorten the residual bone. However, the dilemma is that the bone should be preserved at the most distant level permissible, even with the constraints of the soft tissue envelope [51]. Subsequently, many surgeons have been driven to choosing free flaps or skin grafts for closure , in an attempt to preserve the maximal length of bone possible [52] (Fig. 17.6). Skin grafts placed over bone have proven to have a higher wound failure rate and reoperation rate [51, 53] (Fig. 17.7).

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Fig. 17.6
Split thickness skin graft used to cover the amputation stump in an attempt to maintain maximal stump length


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Fig. 17.7
Failed split thickness skin graft


Complicated Amputations


As in any lower extremity amputation, postoperative complications are prone to happen.


Hemorrhage


Postoperative bleeding is a common complication that may occur with any type of surgery. Bleeding after amputation surgery can be due to a number of causes, namely failure of vessel ligation. It is a must to remove the dressing, identify the bleeder, and stop it. Attempt to control postoperative bleeding or hematoma with compression only is not recommended.


Infection


Infectious complications in war-related injuries remain a long-term challenge and are particularly common due to the mechanism of injury. In combat, high-energy explosive devices are used which instigates extensive contamination with soil, shrapnels and weapon fragments, clothing and even tissue from other casualties [54]. In addition, the high level of tissue destruction and consequent tissue necrosis also contributes to increase in the risk of infection [55].

Infection can range from simple superficial cellulitis to more complicated deeper infections and osteomyelitis (Fig. 17.8). More dreaded complications such as necrotizing fasciitis are also prone to develop. Bacteria infecting these wounds are usually multidrug resistant (MDR), including Acinetobacter baumannii, Pseudomonas aeruginosa, extended spectrum beta lactamase producing Klebsiella species and Escherichia coli, and methicillin-resistant Staphylococcus aureus (MRSA) [35, 37].

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Fig. 17.8
Dehiscence of the amputation stump with evidence of soft tissue infection and osteomyelitis

Life-threatening fungal infections such as Mucormycosis can rarely occur in patients with soil contaminated wounds and massive transfusion and resultant immune-suppression. Such infection should be treated with aggressive debridement and higher level amputation to prevent systemic progression and mortality.

If any sign of infection develops, it is recommended to surgically debride the wound and remove all necrotic and infected tissue. Foreign material, blood clots, bone fragments, and poorly vascularized tissue are a good medium for bacterial proliferation and should be removed. The mainstay of treatment remains surgical intervention and ample irrigation, with the use of intravenous antibiotics as an adjuvant therapy [56, 57]. Wounds are left open and sterile dressings are changed at least once daily.

It is important to stress on irrigation of the wound to reduce necrotic debris and foreign materials and decrease bacterial load [58]. A minimum of three liters of normal saline is recommended for irrigation [59]. Antiseptic solutions such as chlorhexidine have not proven to be superior to saline solution. On the contrary, they have shown to delay or reduce healing with no reduction of infection rates [56]. Local use of antibiotics has also not shown any advantage and is not routinely recommended [60].


Wound Dehiscence


Skin flap breakdown and subsequent wound dehiscence is not an uncommon complication after amputation surgery, leading to prolonged hospital stays [61]. Acute wound dehiscence depends largely on the surgical technique used. It is therefore essential to have good preoperative planning for adequate soft tissue coverage [62]. Blood supply to the skin flaps must be adequate. Closure should be in a tension-free manner, with sutures staying in place for 4 weeks [63].

In case of dehiscence the preferred treatment is surgical. A list of options for proper closure exists. Going by the reconstructive ladder, simple procedures such as debridement and primary closure remain an option. Split thickness skin grafts can also be used, especially when attempting to preserve stump length, but are less recommended as they have a higher complication rate. In attempt to decrease complications of split thickness skin graft, Integra, a bioartificial dermal substitute, may be used. Other options include delayed excision of the skin graft followed by fasciocutaneous advancement flaps [48].

Perforator flaps, whether fasciocutaneous or myocutaneous, can be utilized for closure. They provide vascularized tissue, which protects and nourishes the fractured bone [64]. Finally, myocutaneous free flaps with microsurgical anastomosis are also an option that provides adequate coverage [52]. Such procedures are considered if the overall medical condition of the patient is stable enough to allow further operative therapy.


Chronic Phase of Management



Uncomplicated Amputations


Once the amputation stump has healed the patient must undergo physical therapy. Rehabilitation is a very important phase that considerably affects functional outcome. Psychological and social services support is also warranted.


Complicated Amputations



Ulceration


Ulceration of the amputation stump usually occurs as a consequence of persistent pressure by the prosthesis on the stump [65]. Treatment involves off-loading the weight-bearing area, thus decreasing repetitive trauma and promoting faster healing [66]. It is essential to adjust the prosthesis socket to redistribute the load away from the damaged skin.


Neuroma


Neuromas develop due to improper and irregular regeneration of nerve fibers secondary to trauma [67]. Two types of neuromas exist: spindle and terminal. Spindle neuromas occur due to friction and irritation of a non-disrupted injured nerve. Terminal neuromas develop from completely transected nerve and is thus more common in amputation patients [68].

Patients’ most common presenting symptom is pain. On physical examination the neuroma can sometimes be localized as a palpable nodule. Patients usually experience an electric type of pain along the nerve distribution when the neuroma is palpated, otherwise known as a positive Tinel sign [69].

Proper handling of the nerve during surgery is essential to help prevent neuroma formation. If needed, the nerve is transected using a scalpel rather than electrocautery [68]. Following its transaction, the nerve is either implanted in muscle, bone, vein, or under the fascia [70].

Pharmacologic techniques can also be used to stop neuroma formation. Hot water, electrocoagulation, alcohol, steroids, formalin, hydrochloric acid, phenol, nitrogen mustard, and others have been described to hinder nerve fiber overgrowth. They are either injected directly intraneural at the injury site or at the dorsal root ganglion [67].

Once a neuroma develops, the aim is to control the pain. Pain medications such as nonsteroidal anti-inflammatory drugs are the first line of treatment. Nonsurgical conservative therapy includes injection of the nerve with steroids, performing nerve blocks and even physical therapy to decrease inflammation and scar tissue have been described with controversial efficacy [69].

Surgical resection remains the mainstay of treatment. Resection of the neuroma is performed, followed by burying the nerve end either in muscle, bone, vein, or under the fascia as mentioned before. Capping the nerve end can also be done with either suturing the epineural cuff, or using synthetic caps such as glass or silicone [71].


Phantom Limb Pain


Phantom limb pain is a frequent sequel of amputation surgery. Incidence is reported as high as 60–80% of amputees. Phantom limb pain is classified as neuropathic pain. The underlying mechanism remains unclear and is thought to be related to both peripheral and central factors. The type of pain described is similar to that felt before the amputation. Patients with preoperative pain are more likely to develop phantom limb pain [72].

Treatment for phantom limb pain is challenging. There is no clear evidence-based treatment guidelines for it. An array of medical interventions has been proposed. The most commonly used pharmacologic treatment include tricyclic antidepressants and sodium channel blockers, the same medications that are used to treat neuropathic pain [73]. Nonmedical treatment modalities have been reported, such as transcutaneous electrical nerve stimulation, vibration therapy, acupuncture, hypnosis, and electroconvulsive therapy [72]. Still, there is no clear evidence that supports any of the aforementioned modalities.

It is noteworthy to mention “mirror treatment ” for phantom limb pain, where a mirror is placed across the residual limb as a mean to help reestablish control of the absent limb [74]. Significant decrease in the pain has been reported.


Heterotropic Ossification


Heterotropic ossification (HO) is defined as the formation of lamellar bone inside soft tissue structures where bone does not exist [68]. On presentation, patient complains of pain, joint stiffness, decrease in the range of motion, warmth, swelling, and erythema [75]. It is usually associated with skin adhesions and ulcerations [68].

Prophylaxis against HO includes the use of indomethacin, nonsteroidal anti-inflammatory drug that works on suppressing bone remodeling. A possible benefit to radiation therapy has also been suggested. As for the treatment, conservative management involves also indomethacin and radiation therapy, as well as bisphosphonates [75]. It is fundamental to focus on activity and prosthesis socket modification by a skilled prosthetists to avoid surgical intervention.

Once conservative treatment fails and symptoms progress, it is advised to proceed to surgical excision. Excellent functional outcomes were reported, with minimal recurrence rates.


Prosthesis


Prosthetic devices will never genuinely replace the missing limb, whether functionally or cosmetically. Irrespective of the design used, a difference will always be noted by the amputee. Our aim with the use of prosthesis is to help the amputee incorporate it as part of his body, regain functionality, be comfortable with it, and attain an appropriate level of cosmesis. For this to happen, a skillful team is required to carefully plan the prosthesis. Consideration should be made to the level of amputation, the type of reconstruction done, the level of voluntary control, energy expenditure, and body image. Prosthetic fitting in amputees after combat injury is a challenge since the patient usually has multiple residual limb conditions that make the fitting process difficult.

The socket, the suspension system, the pylon, and the terminal part, usually the foot, make up the prosthesis. We will discuss each part separately.


The Socket


The socket is the most important part of the prosthesis as it is the weight-bearing area. It is custom made to fit the amputation stump. Historically, the weight-bearing area was considered to be at the tip of the stump only. With the newer sockets, the weight is distributed equally to all of the stump, what is known as total surface bearing [76].

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Nov 17, 2017 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Amputations and Prostheses
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