Reviews/Commentaries/Position Statements REVIEW ARTICLE

Focal Entrapment Neuropathies in Diabetes

1 1 AARON VINIK, MD, PHD LAWRENCE COLEN, MD millimeters]) is a risk factor (8,9). It used 1 2 ANAHIT MEHRABYAN, MD ANDREW BOULTON, MD to be associated with work-related injury, but now seems to be common in people in sedentary positions and is probably re- lated to the use of keyboards and type- MONONEURITIS AND because the treatment may be surgical (2) writers (dentists are particularly prone) ENTRAPMENT SYNDROMES — (Table 1). (10). As a corollary, recent data (3) in 514 Peripheral neuropathies in diabetes are a patients with CTS suggest that there is a diverse group of syndromes, not all of threefold risk of having diabetes com- which are the common distal symmetric SYNDROME — Carpal tunnel syn- pared with a normal control group. If rec- . The focal and multifocal drome (CTS) is the most common entrap- ognized, the diagnosis can be confirmed neuropathies are confined to the distribu- ment neuropathy encountered in diabetic by electrophysiological studies. Therapy tion of single or multiple peripheral patients and occurs as a result of median is simple, with diuretics, splints, local ste- nerves and their involvement is referred nerve compression under the transverse roids, and rest or ultimately surgical re- to as mononeuropathy or mononeuritis carpal ligament. It occurs thrice as fre- lease (11). The unaware physician seldom multiplex. quently in a diabetic population com- realizes that symptoms may spread to the Mononeuropathies are due to vasculitis pared with a normal healthy population whole hand or arm in CTS, and the signs and subsequent ischemia or infarction of (3,4). The increased prevalence in diabe- may extend beyond those subserved by nerves (1). Common mononeuropathies tes may be related to repeated undetected the nerve entrapped. Motor weakness is involve cranial nerves III, IV, VI, and VII trauma, metabolic changes, accumulation uncommon, but thenar muscle wasting and thoracic and peripheral nerves, in- of fluid or edema within the confined particularly occurs in the elderly. Tinel cluding peroneal, sural, sciatic, femoral, space of the carpal tunnel, and diabetic sign for percussion at the ulnar, and median. Their onset is acute, cheiroarthropathy (5), rheumatoid arthri- wrist is positive in 61%, and Phalen’s test associated with , and their course is tis, and hypothyroidism (1,3). CTS is wrist flexion is only 46% positive, with a self-limiting, resolving over a period of 6 found in up to one-third of patients with high false-positive rate. Quantitative sen- weeks. They must be distinguished from diabetes, when demonstrated electro- sory tests for the different sensory modal- entrapment syndromes that start slowly, physiologically, but may only be symp- ities, including pain, temperature, and progress, and persist without interven- tomatic in ϳ5.8% (6). It is more common spatial orientation, are notoriously unre- tion (Fig. 1). Common entrapments in- in females and in obese individuals (BMI liable (4). Thus, the very nature of the volve the median, ulnar, and peroneal Ͼ30 kg/m2) and affects the dominant trouble goes unrecognized, and an oppor- nerves, the lateral cutaneous of the thigh, hand (7). It occurs in 2% of the general tunity for successful therapeutic interven- and the in the tarsal canal. The population, 14% of diabetic subjects tion is often missed. Electrophysiological entrapment neuropathies are highly prev- without diabetic polyneuropathy, and studies measure the speed of conduction alent in the diabetic population, one in 30% of diabetic subjects with diabetic across the carpal tunnel, and median sen- every three patients has one, and it should polyneuropathy. It peaks at around sory nerve conduction studies are com- be actively sought in every patient with 40–60 years of age and an increased pared with radial and/or ulnar sensory the signs and symptoms of neuropathy “wrist index” (wrist depth/wrist width [in latencies. Their interpretation is made dif- ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● ficult if there is a coexisting peripheral From 1The Diabetes Institute, Eastern Virginia Medical School, Norfolk, Virginia; and the 2Manchester Royal neuropathy affecting the upper limbs or if Infirmary, Oxford, U.K. there are no symptoms of CTS. Demyeli- Address correspondence and reprint requests to Aaron Vinik, MD, The Diabetes Institute, Eastern Virginia nation is thought to be the primary patho- Medical School, 855 W. Brambleton Ave., Norfolk, VA 23510. E-mail: [email protected]. logical abnormality. Received for publication 2 February 2004 and accepted in revised form 11 April 2004. A.V. has received consultant’s fees from or served on the speaker’s bureaus for Pfizer, Genetech, Merck, activity can be particularly useful in dis- Eli Lilly, Athena, Bristol Meyers Squibb, Knoll Pharmaceuticals, GlaxoSmithKline Beecham, Boston Medical tinguishing this from distal symmetric Technologies, Neurometrix, Guilford Pharmaceuticals, R.W. Johnson Pharmaceutical Research Institute, polyneuropathy (DSPN) and the double- Takeda, TEVA Pharmaceutical Industries, AstraZeneca, Synergy Biosciences, Amgen, Forest Laboratories, crush syndrome of C7–8 Sigma Tau Research, and Sankyo; and has received grant support from GMP-Endotherapeutics, the Amer- (12). The high sensitivity and specificity ican Diabetes Association, the U.S. Department of Housing and Urban Development, the National Aeronau- tics and Space Administration, Eli Lilly, AstaMedica, the National Institute on Aging, R.W. Johnson, the of nerve conduction studies make them National Institutes of Health, the Juvenile Diabetes Foundation International, Takeda America, the Depart- the most valuable diagnostic method for ment of Health and Human Services Public Health Services, and PPD Development. CTS (80% sensitive). Wrist-palm stimu- Abbreviations: CTS, ; DSPN, distal symmetric polyneuropathy; NCV, nerve lation is the most sensitive technique conduction velocity; PSSD, pressure-specified sensory device; TTS, syndrome. A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion (61% sensitivity in diagnosis of CTS). factors for many substances. Moreover, it is the only technique to di- © 2004 by the American Diabetes Association. agnose subclinical cases and differentiate

DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004 1783 Focal entrapment neuropathies in diabetes

Table 1—Clinical features of entrapment syndromes: location, impairments, and diagnosis

Location of the most Distribution common of sensory Distribution of Diagnosis by Differential Nerves entrapments impairment motor impairment Signs NCV diagnosis Median nerve Wrist (CTS) Palmar aspects of Weakness and at- Tinel’s sign, Phalen’s Wrist/palm stim- C8 radiculopathy, I–III, 0.5 IV fin- rophy of abduc- maneuver, carpal ulation proximal com- gers, medial as- tor policis brevis compression test, pressions of me- pect of the palm, and weakness of dian nerve and intact thenar thumb opposition eminence Elbow (cubital Palmar aspects of V, Weakness and atro- Tapping or pressure Below/above elbow C8-T1 radiculopathy, tunnel syn- 0.5 IV fingers, phy of adductor over the ulnar stimulation brachial plexoapthy drome) medio-dorsal as- digiti minimi, nerve at the medial (medial cord), and pect of the hand, hypothenar, and epicondyle repro- ulnar nerve entrap- and hypothenar intrinsic muscle of duces sensory ment at the wrist eminence the hand symptoms, Fro- ment’s sign Elbow (radial Dorsal aspect of the Drop wrist: weak- Aching and soreness NCV–electromyo- Wartenberg’s syn- groove) forearm, hand, ness of the exten- in the elbow re- graphy activity* drome, tennis and fingers I–III sors of the hand gion, weakness of elbow, radiculopa- and 0.5 IV and fingers, intact supination and thy C7, brachial function of the extension of index (poste- forearm extensors finger and hand rior cord) Peroneal nerve Fibula head Lateral aspect of the Drop foot: weakness Tapping or pressure Above/below fibula Compression at the leg and dorsum of of the extensors of below the fibula stimulation knee level, radicu- the foot foot and toes head provokes sen- lopathy L5 sory symptoms Tibial nerve Ankle-tarsal Plantar: medial and Atrophy of the in- Tinel’s sign, tapping Sensory medial and Radiculopathy S1, tunnel lateral surfaces trinsic muscles in the nerve distri- lateral plantar polyneuropathy of the foot bution nerves (DSPN), and Morton’s neuroma Lateral cutaneous Ilioinguinal liga- Lateral aspect of None Extremely sensitive Above/below ilio- Femoral neuropathy, nerve of the ment (meralgia the thigh skin in correspond- inguinal liga- radiculopathy thigh paresthetica) ing dermatome ment stimulation L2–3, and lumbar plexopathy *Radial nerve entrapment requires conduction velocity done over muscles of forearm because, unlike the ulnary median nerves, the radial nerve does not innervate muscles in the hand. entrapment from DSPN. Combined en- ness, and failure of nonsurgical treatment. 25 nondiabetic patients. Global symptom trapment of median and ulnar nerves can Of particular note is the very elegant scores as well as electrophysiological evi- mimic DSPN and can only be distin- study by Ozkul et al. (13). They com- dence of recovery of nerve function were guished by nerve conduction velocity pared the outcome of carpal tunnel re- evaluated at 1 month and again at 1 year (NCV) with median nerve stimulation in lease in 22 diabetic patients with that of after decompression. They observed im- the palm. The mainstays of nonsurgical treat- ment are resting the wrist, aided by the placement of a wrist splint in a neutral position for day and night use, and the addition of anti-inflammatory drug med- ications. Injections of cortisone into the carpal tunnel may provide short-lived re- lief and, in the majority of cases, repeat injections are required. Surgical section- ing of the transverse carpal ligament pro- vides variable degrees of pain relief but does not particularly benefit muscle wast- ing or sensory loss (2). The decision to proceed with surgery should be based on several considerations, including severity of symptoms, appearance of motor weak- Figure 1

1784 DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004 Vinik and Associates provement in median nerve latencies and pressure-sensing device for the detection flexor carpi ulnaris aponeurosis, and ul- sensory conduction velocity in both of entrapment and reported in 72 clinical nar nerve transposition (18). groups, but the degree of recovery was entrapment syndromes that the pressure- less and slower in the diabetic population. specified sensory device (PSSD) was RADIAL NERVE Specifically, they excluded insulin- 100% sensitive compared with electrodi- ENTRAPMENT — This is rare (0.6%), treated diabetic subjects because of the agnostic testing. They conclude that the occurring as a consequence of radial neurotrophic effects of insulin and of con- PSSD has a high sensitivity but low spec- nerve compression in the spiral groove. It ditions such as , ificity because it detected abnormalities in presents with the characteristic motor cervical radiculopathy, brachial plexopa- sensory function in 25% of patients who deficits of and sensory impair- thy, , and lesions had negative electrodiagnostic tests. An ment over the dorsum of the hand, intact of the 6th cervical root, as well as previous alternative explanation is that the subjec- elbow extension, and sensation in poste- medical treatments with steroids, diuret- tive PSSD gives 25% more false-positives rior arm and forearm distribution. The ics, or splints and surgery. They conclud- than electrodiagnostic testing and thus causes of that mostly ed that factors other than compression are would not be reflecting changes in entrap- lead to weakness of muscles innervated by important in entrapment syndromes in ment. This would be more in keeping motor branches include humeral fracture, diabetes and suggest that sorbitol accu- with the lack of specificity of quantitative blunt trauma over the posterolateral as- mulation, myoinositol deficiency, and ac- sensory tests shown by Perkins, Olaleye, pect of the arm and forearm, and external cumulation of advanced glycation end and Bril (4) and further emphasizes the compression of radial nerve in the spiral products may be relevant to the slowing need to use a “gold standard” for the di- groove and posterior interosseous nerve of recovery in diabetes. It may also of agnosis and quantitation of response to (the distal motor branch) in the forearm. course also relate to the impairment in therapy. Isolated neuropathy of the superficial ra- nerve regeneration in diabetes (14). dial nerve can be caused by entrapment Whatever the case, it is abundantly clear ULNAR ENTRAPMENT — The sec- and is known as Wartenberg’s syndrome, that one must not neglect the burden of ond most common entrapment neuropa- whereas external compression of the same dysmetabolism on diabetic nerves that are thy (2.1%) occurs as a result of ulnar sensory branch is known as wristwatch or entrapped, and attention to metabolic nerve compression immediately distal to bracelet neuropathy. Electrophysiologi- control may be essential to permitting ad- the ulnar groove beneath the edge of the cally, the amplitude is reduced compared equate recovery of the nonentrapped flexor carpi ulnaris aponeurosis in the cu- with the same response from the con- nerve. Aszmann, Kress, and Dellon (15) bital tunnel. It may develop as a result of tralateral radial as well as the ipsilateral carried out decompression of the median deformity at the elbow joint secondary to median sensory nerve. Decreased con- nerve at the wrist, the ulnar nerve in the fracture or as a consequence of prolonged duction velocity through the compressed ulnar canal at the elbow, and the posterior pressure during surgery and has been segment in the forearm and arm is still the tibial nerve in 20 diabetic patients who most commonly associated with alcohol- hallmark of diagnosis (19). Management had had diabetes for 14.8 years and com- ism. Typical symptoms include painful is conservative, with pressure relief in pared the responses in operated and un- paresthesiae in the fourth and fifth digits sensory neuropathy. operated limbs (a total of 31 nerves) in associated with hypothenar and in- patients who had a positive Tinel sign, terosseous muscle wasting and weakness. COMMON PERONEAL ostensibly indicative of surviving neu- Froment’s sign (weakness of adduction ENTRAPMENT — Peroneal nerve rons. They also excluded patients with ab- and opposition of thumb) and impaired entrapment at the level of the fibula head sent electrical impulses in whom dead flexion of the fourth and fifth fingers are is the most common entrapment syn- nerves were unlikely to respond. Overall, classic signs. The etiology of ulnar nerve drome in the lower limbs. It is due to the there was a 79% improvement of loss of entrapment includes trauma, arthritis, ease of external compression of the pero- two-point discrimination in the operated and systemic diseases (less often than in neal nerve, while under general anesthe- side compared with a 32% progression of CTS). As in CTS, conduction through the sia, while crossing legs, while sleeping in neuropathy in the unoperated nerves. elbow is decreased. A C8-T1 radiculopa- older people especially, and during Upper limbs fared better than lower limbs thy, , and en- weight loss. It needs to be distinguished (88 vs. 69% improvement). Unfortu- trapment at the wrist must be excluded. from an L5 radiculopathy (foot drop) nately, these results must be interpreted The pathology is a combination of de- when tripping and fractures occur, espe- with caution. The test is not a good mea- myelination and axonal degeneration. cially in older people. Involvement of the sure of sensory function (4): no measure The key electrophysiological findings in- motor fibers in the common peroneal of conduction across the entrapment site clude low-amplitude ulnar sensory nerve nerve results in weakness of the dorsiflex- was shown to confirm entrapment, no action potentials, reduced sensory NCV, ors and foot drop, but the loss of the mo- Tinel-negative patients were included, and fibrillation potentials in the interossei tor supply to the tibialis anterior muscle and no sham operative procedure was (17). Management of patients is primarily also leads to weakness in eversion. A sim- carried out. The analysis of a responder conservative, with advice to avoid pres- ple bedside test entails asking the patient rate as opposed to the degree of the re- sure to this area because the results of sur- to stand on his or her heels and see sponse, which might have depended on gery are very poor. However, if symptoms whether he or she is unable to raise the the severity of the lesion, is also not ad- and signs progress, then a number of ap- forefoot off of the ground. This is accom- dressed. Indeed, the same group of inves- proaches may be used. They include me- panied by a sensory deficit in the lateral tigators (16) have proposed use of a dial epicondylectomy, transaction of the anterior tibial compartment, but charac-

DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004 1785 Focal entrapment neuropathies in diabetes teristically no pain or paresthesiae. Tinel nel syndrome (TTS) (23) is a painful low- be the peripheral neuropathy of diabetes sign may be positive and is elicited by er-limb entrapment. Passing through the and the “second crush” compression of striking the peroneal nerve at the neck of tarsal tunnel, the tibial nerve innervates the tibial nerve at the tarsal tunnel. If pa- the fibula, which produces pain and tin- only muscles of the sole, and clinical signs tients are carefully selected, release of the gling in the distribution of the peroneal are mostly sensory. Foot pain may be se- tibial nerve through the tarsal tunnel in nerve supply. Diabetes was thought to be vere, burning, and worse on standing and the diabetic patient may improve plantar a relatively uncommon cause of peroneal walking. Tinel sign on the underside of sensibility and help prevent plantar ulcer- nerve palsy (5–12%) (20); however, in the medial malleolus with atrophy of the ation and ultimate lower-extremity am- the Women’s Health and Aging Study sole muscles is typical. Weakness is rare putation. Several recent studies lend (21), weakness of dorsiflexion occurred because most of the small foot muscles credence to this notion, though study de- in two-thirds of women Ͼ65 years of age (flexor hallucis longus) are not damaged sign flaws need to be rectified before uni- and more so if diabetes was superimposed in TTS. Pain on the inside of the foot must versal acceptance of this principle is on aging. Conduction blocks were found be distinguished from other causes of achieved. Caffee et al. (27) presented data across the fibular head and suggested ex- pain, for example, a Morton’s neuroma, on 36 patients collected over a 9-year pe- ternal compression at the fibular head , heel spurs, arthritis or riod from 1989 to 1997 reviewed retro- during sleep with the legs crossed or in bone spurs, and early Charcot’s neuroar- spectively. The mean follow-up was 32 bedridden patients. Other causes are an- thropathy. Magnetic resonance imaging months, and these were patients who had esthesia, being placed in the stirrups for of the foot can be very helpful to identify severe disease, with foot ulcers in 11 pa- obstetrical and gynecological procedures, neuromas and shows edema of bones in tients and painful paresthesiae in 28. Fif- and are a result of inappropriately placed the midfoot with Charcot’s, which pre- ty-eight decompressions were done in 36 plaster casts following lower-limb frac- sents as a hot foot with increased blood patients followed for 7–84 months. In tures. An important differential is a radic- flow (24). It may also be a manifestation these studies, the Semmes-Weinstein ulopathy involving the L5 root. Features of systemic disease (25). Once these are monofilaments were used to monitor re- that define L5 involvement include pain excluded, NCV can be informative in the sponses. Twenty-four of 28 patients had in the lower back and additional loss of case of a normal plantar response from complete relief of pain, some while on the inversion. Another critical differential is one leg and an abnormal one from the operating table and still under anesthetic, spinal stenosis with claudication of the symptomatic leg in unilateral TTS. TTS is and 13 of 24 had improved subjective cord. These people have pain in the but- not difficult to diagnose clinically when sensation. They concluded that there is tocks radiating down the leg made worse DSPN is not severe and NCV is moder- some room for optimism but had no ob- when walking downhill and relieved by ately abnormal. Mild symmetric peroneal jective data of recovery, the only record of bending forward. It is due to constriction and tibial NCV abnormality, with intact change being that reported on by the pa- of the anterior spinal artery, and emphasis ankle jerks and sensation of the dorsal as- tients. The failure in 50% of patients is at the watershed sites, such as T12- pect of the foot, together with the above- attributed to the advanced status of their L1.MRI of the spine, can be very useful. mentioned clinical signs, are the most disease and that objective testing of sen- Electrophysiological studies help to dis- important diagnostic features of TTS. sation is an oxymoron despite the reports tinguish these syndromes from peroneal When the neuropathy is severe, then di- by Wieman and Patel (28) and Dellon entrapment. In such cases, there is demy- agnosis may be impossible. A positive (29) of improved two-point discrimina- elination with conduction block in mild Tinel sign, tapping just below the medial tion after surgical decompression. lesions, with a marked loss of amplitude malleolus, may be helpful, but unfortu- In the report by Wieman and Patel that is presumably secondary to axonal nately may also simply reflect nerve dam- (28) on 33 limbs in 26 patients, 32 had a degeneration in more severe lesions (22). age in peripheral neuropathy, which is a positive Tinel sign, yet 19 of 26 re- Because the majority of these lesions are negative sign, suggesting that nerve dam- sponded and 7 with positive Tinel signs caused by external pressure that, if re- age predicts a poor outcome of surgery. did not. Thus, as Dellon (29) showed, lieved, will result in the resolution of the Controversy exists as to the role tarsal there may be an 80% response in Tinel- motor deficit within 3–6 months, a con- tunnel release has in the management of positive people but failure in 20% would servative approach is advocated, with re- the diabetic patient with poor plantar foot be in agreement with the study by Wie- moval of pressure and a foot brace in the sensibility. Due to the intrinsic swelling of man and Patel (28), suggesting that the interim. peripheral nerves in diabetes (endoneural sign is not a good predictor of response. edema secondary to increased sorbitol Unfortunately, in the Wieman and Patel TARSAL TUNNEL levels within the peripheral nerve), an in- study (28), neither foot pressures nor SYNDROME — The tarsal tunnel is creased incidence of compression neu- electrodiagnostics showed any changes in homologous to the carpal tunnel in the ropathy has been well documented. The the operated patients, and only symptoms upper extremity. Through this space, double-crush syndrome as described by of pain improved. The objective measures which lies between the medial malleolus Upton and McComas (26) may be applied of two-point discrimination fell equiva- and the calcaneous, passes the tibial nerve to the diabetic patient. This hypothesis lently from 15.1 Ϯ 4 to 11.1 Ϯ 3.5 arbi- and its branches as well as the extrinsic states that when multiple “subclinical” trary units in responders and from 13.7 Ϯ flexor tendons of the foot and ankle. The nerve compressions exist in series, they 3 to 11.1 Ϯ 2.5 arbitrary units in nonre- boundaries of the tunnel are fairly rigid; may be “additive” and give rise to symp- sponders, pointing out the lack of validity therefore, any swelling within the tunnel toms, even though each compression, by of this as a test of response to decompres- will compress the tibial nerve. Tarsal tun- itself, would not. The “first crush” would sion. Thus, these studies have not clearly

1786 DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004 Vinik and Associates established the role of decompression in surgical decompression is a viable op- MP: Evaluation of age, body mass index entrapment syndromes, left us flounder- tion (32). and wrist index as risk factors for carpal ing with regard to the value of a positive Other nerves that may be involved in- tunnel syndrome severity. Muscle Nerve Tinel sign over the ankle, and created clude the sciatic and obturator nerves. 25:93–97, 2002 some consternation among those people They can be a cause of significant motor 10. Hamann C, Werner R, Franzblau A, who are concerned that this is being ad- deficit; however, they are extremely rare Rodgers P, Siew C, Gruninger S: Preva- lence of carpal tunnel syndrome and me- vocated as a procedure for common or and their management is conservative. dian mononeuropathy among dentists. garden diabetic neuropathy in the ab- In conclusion, up to one-third of pa- J Am Dent Assoc 132:163–170, 2001 sence of entrapment, even when there is tients with diabetes are found to have 11. Herrmann D, Logigian E: Electrodiagnos- no evidence of recoverable nerve func- some form of entrapment syndrome. The tic approach to the patients with sus- tion. Indeed, as Carneiro (30) pointed diagnosis rests on an index of suspicion pected mononeuropathy of the upper out, there is a need to grade the severity of and electrophysiological tests demon- extremity. Neurol Clin 20:451–478, 2002 the entrapments using measures of sen- strating for the most part a block in nerve 12. Hurst L, Weissberg D, Carroll R: The re- sory deficits with validated tests, the pres- conduction across the site of the lesion. lationship of the double crush tunnel syn- ence of a Tinel sign, the time taken for The value of the Tinel sign in predicting drome (an analysis of 1000 cases of carpal Phalen’s test to become positive, and the outcome needs validation, and quantita- tunnel syndrome). J Hand Surg 10:202– presence of motor features and atrophy to tive sensory tests are notoriously unreli- 204, 1985 identify the best candidates for surgery. able. There are clear indications for 13. Ozkul Y, Sabuncu T, Kocabey Y, Nazligul Y: Outcomes of carpal tunnel release in We would go further than that and add surgery when conservative medical ther- diabetic and non-diabetic patients. Acta that a conduction block must be present apy fails, and it is not yet clear that de- Neurol Scand 106:168–172, 2002 at the site, that there should not be such compression should be considered in the 14. Maxfield EK, Love A, Cotter MA, Cam- severe diabetic neuropathy to preclude treatment of diabetic neuropathy in the eron NE: Nerve function and regeneration distinction of this from entrapment, and absence of compression. Prospective in diabetic rats: effects of ZD-7155, an that controlled sham operations have to studies on the role for decompression us- AT1 receptor antagonist. Am J Physiol be compared with unentrapment for relief ing accepted measures are clearly needed. 269:E530–E537, 1995 of symptoms, if this is the only measure- 15. Aszmann O, Kress K, Dellon A: Results of ment. decompression of peripheral nerves in diabetics: a prospective, blinded study. The mainstays of nonsurgical treat- References Plast Reconstr Surg 106:816–822, 2000 ment are avoidance of the use of the joint, 1. Vinik AI, Holland MT, LeBeau JM, Liuzzi 16. Tassler PL, Dellon A: Correlation of mea- placement of a splint in a neutral position FJ, Stansberry KB, Colen LB: Diabetic surements of pressure perception using neuropathies. Diabetes Care 15:1926– for day and night use, anti-inflammatory the pressure-specified sensory device with 1975, 1992 medications, and targeted injections of lo- electrodiagnostic testing. J Occup Environ cal anesthetics and steroids. Surgical 2. Dawson DM: Entrapment neuropathies of the upper extremities. N Engl J Med 329: Med 37:862–866, 1995 treatment consists of sectioning the of- 17. Shady W, Abuaisha B, Boulton A: Obser- fending ligament. The decision to pro- 2013–2018, 1993 3. Kapritskaya Y, Novak C, Mackinnon S: vation of severe in dia- ceed with surgery should be based on Prevalence of smoking, obesity, diabetes betes. J Diabetes Complications 12:128– several considerations, including severity mellitus and thyroid disease in patients 132, 1998 of symptoms, appearance of motor weak- with carpal tunnel syndrome. Ann Plast 18. Goldberg BJ, Light T, Blair S: Ulnar neu- ness, and failure of nonsurgical treatment. Surg 48:269–279, 2002 ropathy at the elbow: results of median 4. Perkins B, Olaleye D, Bril V: Carpal tunnel epicondilectomy (Abstract). J Hand Surg LATERAL FEMORAL syndrome in patients with diabetic poly- 182:14A, 1998 CUTANEOUS NERVE neuropathy. Diabetes Care 25:565–569, 19. Carlson N, Logigian L: Radial neuropathy entrapments and other focal neuropathy. ENTRAPMENT — Compression of 2002 5. Chaudhuri KR, Davidson AR, Morris IM: Neurol Clin 17:499–523, 1999 the lateral femoral cutaneous nerve (mer- 20. Garland H, Moorehouse D: Compressive algia paresthetica) is uncommon. It re- Limited joint mobility and carpal tunnel syndrome in insulin dependent diabetes. lesions of the external popliteal (common sults in pain, paresthesiae, and sensory Br J Rheumatol 28:191–194, 1989 peroneal) nerve. BMJ 21:1373–1378, 1952 loss in the lateral aspect of the thigh (31) 6. Wilbourn AJ: Diabetic entrapment and 21. Resnick H, Stansberry K, Harris T, and can lead to significant disability when compression neuropathies. In Diabetic Tirivedi M, Morgan P, Smith K, Vinik A: the diagnosis is missed. Obesity and dia- Neuropathy. Dyck PJ, Thomas PK, Eds. Diabetes, peripheral and old age disabil- betes are the most common causes, fol- Philadelphia, Saunders, 1999, p. 481–508 ity. Nerve Muscle 25:43–50, 2002 lowed by trauma due to external injury of 7. Becker J, Nora D, Gomes I, Sringari F, 22. Katirji M, Wilbourn A: Common peroneal the nerve as it runs down the lateral aspect Seitensus R, Panosso J, Ehlers J: An eval- mononeuropathy: a clinical and electro- ofthethigh.Mostwillresolvespontaneous- uation of gender, obesity, age and dia- physiologic study of 116 lesions. Neurol- ly and are therefore conservatively man- betes mellitus as risk factors for carpal ogy 38:1723–1728, 1988 23. Sammarco G, Chalk D, Feibel J: Tarsal aged, using focal nerve block at the tunnel syndrome. Clin Neurophys 113: 1429–1434, 2002 tunnel syndrome and additional nerve le- inguinal ligament, with a combination of 8. de Krom M, Kester A, Knipschild P, sions in the same limb. Foot Ankle 14:71– and corticosteroids as well as Spaans F: Risk factors for carpal tunnel 77, 1993 rest, and reduction or elimination of ag- syndrome. Am J Epidemiol 6:1102–1110, 24. Shapiro SA, Stansberry KB, Hill MA, gravating factors. However, in severe 1990 Meyer MD, McNitt PM, Bhatt BA, Vinik cases, when medical management fails, 9. Kouyoumdjian JA, Zanetta DM, Morita AI: Normal blood flow and vasomotion in

DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004 1787 Focal entrapment neuropathies in diabetes

the diabetic Charcot foot. J Diabetes Com- 815, 2000 J Med 66:159–164, 1999 plications 12:147–153, 1998 28. Wieman T, Patel V: Treatment of hyper- 31. Mulder DW, Lambert EH, Bastron JA, 25. Oloff L, Jacobs A, Jaffe S: Tarsal tunnel esthetic neuropathic pain in diabetics: de- Sprague RG: The neuropathies associated syndrome: a manifestation of systemic compression of the tarsal tunnel. Ann Surg with diabetes mellitus: a clinical and elec- disease. J Foot Surg 22:302–307, 1983 221:660–664, 1995 tromyographic study of 103 unselected 26. Upton AR, McComas AJ: The double 29. Dellon A: Treatment of symptomatic dia- diabetic patients. 11:275–284, crush in nerve entrapment syndromes. betic neuropathy by surgical decompres- 1961 Lancet 2:359–362, 1973 sion of multiple peripheral nerves. Plast 32. Ivins G: Meralgia parethetica, the elusive 27. Caffee H: Treatment of diabetic neuropa- Reconstr Surg 89:689–697, 1992 diagnosis: clinical experience with 14 thy by decompression of the posterior 30. Carneiro R: Carpal tunnel syndrome: the adult patients. Ann Surg 232:281–286, tibial nerve. Plast Reconstr Surg 106:813– cause dictates the treatment. Cleve Clin 2000

1788 DIABETES CARE, VOLUME 27, NUMBER 7, JULY 2004