Introduction
Excluding major trauma, amputation of the lower limb is most frequently
done in diabetics following ‘diabetic foot’ problems.
These amputations are largely preventable by adequate foot care, control
of diabetes and in selected cases by surgery to restore sensations
in neuropathic feet.
This article is written to introduce this concept and answer the possible
queries.
1. What is the purpose of this surgery
2. Case selection
3. What is expected of the patient
4. What will happen to the patient if he undergoes this surgery
5. What are the possible advantages and risks
1. What is the purpose of this surgery
Diabetes is a disease state that is usually detected late. The diabetic
may already have advanced “Diabetic Peripheral Neuropathy”
at the time of diagnosis.
A diagnosed or undiagnosed diabetic may not be aware and may not even
accept that he has loss of “protective pain sensation”
in the soles of his feet as some of the other modalities of sensation
are preserved. However the nerve damage can be detected clinically
and proved by electrodiagnostic studies (EMG and NCS).
Feet lacking this protective sensation are subjected to repetitive
injury, as there is no pain feedback to enforce rest. The person continues
to walk on these injured feet thereby creating the so-called “diabetic
foot”. This finally puts the limb and life at risk.
Here lies a no-win situation unless the lost sensations can be restored.
Perhaps the nerve damage can be prevented by adequate control of diabetes.
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Fig.
1 : Pre and post-operative electrodiagnostic studies
in a case confirming the improvement, as shown below. NCS of
Posterior Tibial Nerve, CMAP obtained from the Abductor Hallucis
after stimulating the nerve at the ankle and at the knee.
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Fig.
2 : Extended decompression of neuro-vascular bundle
of posterior compartment of leg containing the tibial nerve,
posterior tibial artery and the venae comitantes.
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3 : Preoperative and 21 days postoperative clinical evaluation
of ‘Stoking’ area sensory loss. |
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However, our study
has shown that when the neurovascular bundle containing the tibial
nerve, the posterior tibial artery and the venae comitantes is decompressed
surgically over an extensive segment, there is a recovery of the previously
absent plantar protective sensation. This improvement has been documented
by electrodiagnostic studies performed before decompression and a
few months after the surgery (Fig. 1). Perhaps there is also progress
towards normalization of the autonomous supply and an improvement
of the vascularity.
Hitherto a limited decompression of the nerve in the ankle region
has been reported and has given inconsistent results.1-4
With the aid of currently available electrodiagnostic equipment it
is possible to test the nerve during the operation to confirm the
adequacy of the release. Based on this it has been observed that the
release had to be extended more proximally than was previously thought
to be adequate in various nerves affected by leprosy.5-8
In all our cases the release was extended from the ankle to the upper
calf (Fig. 2). The sensory improvement was satisfactory in all the
operated limbs as the protective sensation of the feet recovered (Fig.
3).
This surgery has had promising results in an otherwise dubious scenario
wherein it was believed that the nerve damage in diabetes is irreversible.
2. Case selection
All diabetics are not prone to foot problems. The following criteria
help to identify those at risk:
High risk foot
* Presence of an ulcer
* Past history of ulcer
* Loss of protective sensation (neuropathy severe enough that they
cannot feel injury) or
* Peripheral vascular disease 
rest pain/claudication/absent pedal pulses
Additional risk factors
* Absent ankle reflexes
* Biomechanical problems of the foot
stiff ankle, claw toes, Charcot arthropathy, etc.
* Dry cracked skin, callus
* Impaired vision, lack of flexibility, physical disability, elderly,
living alone
Of these people only those having a foot ulcer or past history of
an ulcer attributable to peripheral neuropathy (as confirmed by electro-diagnostic
studies) and not suffering from peripheral ischaemic disease (as confirmed
by palpable peripheral pulses) are selected for the neurolysis.
The surgery is performed only after diabetes is under control and
the foot infection (if present) is also under control.
3. What is expected of the patient
* Fortnightly visit to
— Diabetologist
— Plastic surgeon
* Good foot care as per the information provided.
* Electro-diagnostic studies when advised.
* Maintain medical records in a file and bring the file at every visit.
* The instructions given after operation should be followed meticulously.
* All new developments must be recorded by the patient or the family
doctor.
* The patient’s detailed observation of any changes is essential
and must be reported immediately.
* Any information that the patient gives on the phone or by any other
means of communication must also be recorded.
4. What will happen to the patient if he undergoes this surgery
The scar will extend from the medial malleolus to the upper part of
the calf.
The expected result is that there should be improvement in sensation
in the foot. Although a return of sensation would place the patient
in the low risk category for further foot problems, he is expected
to follow the foot care instructions provided.
The other leg can be operated upon at the same time or after the complete
healing of the incision.
Although improvement is expected, if diabetes is not controlled thereafter,
the nerve may once again be affected in a similar way.
The patient must come for regular periodic follow-up for as long as
possible.
5. What are the possible disadvantages and risks?
The belief that diabetics have a higher risk of developing post-operative
complications has been proved to be a myth. Once diabetes is controlled
and maintained, the risk of post-operative complications would be
the same as that in any non-diabetic.9
Specific to the surgery there is a theoretical possibility of abnormal
sensations in the post-operative period which we have not encountered
in any of our cases.
References
1. Aszmann OC, Kress KM, Dllon OTRCHT, Dellon AL. Results of decompression
of peripheral nerves in diabetes : a prospective, blinded study. Plast
Reconstr Surg 2000; 106 : 816.
2. Caffee HH. Treatment of diabetic neuropathy by decompression of
the posterior tibial nerve. Plast Reconstr Surg 2000; 106 : 813.
3. Dellon AL. Treatment of symptomatic diabetic neuropathy by surgical
decompression of multiple peripheral nerves. Plast Reconstr Surg 1992;
89 : 689.
4. Wieman TJ, Patel VG. Treatment of hyperesthetic neuropathic pain
in diabetics - decompression of the tarsal tunnel. Annals of Surgery
1995; 221 : 660.
5. Turkof E, Tambwekar SR, Mansukhani K, Millesi H, Mayr N. Intra-operative
spinal root stimulation to detect the most proximal site of leprous
ulnar neuritis. Lancet 1994; 343 : 1604.
6. Turkof E, Tambwekar SR, Manuskhani K, Millesi H, Mayr N. Intraoperative
electroneurodiagnostics to detect a second granuloma in the cubital
area of median nerves affected by leprosy. A new approach to prevent
incomplete surgery. Int J of Leprosy 1995; 63 : 409.
7. Turkof E, Tambwekar SR, Kamal S, El-Dharavi M, Mansukhani K, Soliman
H, Ciovica R, Mayr N. Lepsory affects facial nerve at the main trunk:
neurolysis can probably avoid transfer procedures. Plast Reconstr
Surg 1998; 102 : 1565.
8. Richard B, Khatri B, Knolle E, Lucas S, Turkof E. Leprosy affects
the Tibial Nerves Diffusely from the Middle of the Thigh to the Sole
of the Foot, Including Skip Lesions. Plast Reconstr Surg 2001; 107
: 1717-24.
9. Zerr KL, Furnary AP, Grunkmeier GL, Bookin S, Kanhere V, Starr
A. Glucose control lowers the risk of wound infection in diabetics
after open heart operations. Annals of Thoracic Surgery 1997; 63 (2)
: 356-61.
*Department
of Plastic Surgery; **Neurology and ***Diabetes, EMG, The Medical
Research Centre, Bombay Hospital, 12, New Marine Lines, Mumbai 400
020.
