Occupational and Environmental Medicine 1995;52:21 1-213 211 Bilateral median and ulnar neuropathy at the wrist in a parquet floorer Occup Environ Med: first published as 10.1136/oem.52.3.211 on 1 March 1995. Downloaded from M dell'Omo, G Muzi, T A Cantisani, S Ercolani, M P Accattoli, G Abbritti Abstract The most common entrapment neuropathy' Many cases of work related compression in the upper limbs is due to compression of neuropathy of the ulnar and median the median nerve at the wrist, which causes nerves at the wrist have been described. the so called carpal tunnel syndrome (CTS) .12 This report presents a case of bilateral Compression syndromes of the ulnar nerve at distal neuropathy of the median and or below the wrist have also been well docu- ulnar nerves in a parquet floorer, who mented.' I laid wooden block flooring by hand and Although occupational hazards may play a used the palms and volar surface of both part in the aetiopathogenesis of these syn- hands to hit the blocks into place. He also dromes, they often pass unrecognised.' used an electric sander and polisher. This case report of compression neuro- Bilateral numbness and paraesthesias in pathy in the upper limbs is unusual because of all fingers had been present for about one the bilateral involvement of the median and year. Clinical examination was normal; ulnar nerves. The patient was a parquet the neurological assessment indicated floorer, an occupation that is not included slight impairment in response to tactile, among those at risk of CTS and distal neu- heat, and pain stimuli in all 10 fingers. ropathy of the ulnar nerve. Electroneurography showed increased distal motor latencies of median and ulnar nerves at both wrists, although the Case report lower limbs were normal. The results of A 43 year old man was referred to the blood, urine, and instrumental tests Department of Occupational Medicine, excluded systemic disease or local factors University of Perugia, Italy, because numb- that could cause compression neuro- ness and paraesthesias had been present in all pathy. After stopping work for three fingers of both hands for about one year. No months, the clinical picture and electro- other symptoms were present. A floorer for Institute of neurographic results improved. These about 25 years, the patient was mainly occu- Occupational data support the hypothesis that the pied in hand laying parquet flooring. At work Medicine, University http://oem.bmj.com/ ofPerugia, Via E dal damage to the median and ulnar nerves he used different glues and had the habit of Pozzo, 06100 Perugia, had been caused by the patient's way of pressing each wooden block into position with Italy working, which provoked repeated bilat- the base of the palm and the volar surface of M dell'Omo G Muzi eral microtrauma to his wrists. To diag- both wrists. For about 80 hours every month, S Ercolani nose work related multiple neuropathy he also used a heavy electric floor sander and M P Accattoli can be difficult and an accurate work polisher that produced vibrations. The patient G Abbritti history is necessary. Preventive measures presented no case history of neurological, Neurophysiopathology health care are for endocrine or metabolic no current on October 2, 2021 by guest. Protected copyright. Unit, Ospedale and diligent required disease, "Silvestrini", 06100 this category ofworker. connective tissue disease, or previous wrist Perugia, Italy and hand trauma. T A Cantisani (Occup Environ Med 1995;52:21 1-213) A neurological examination showed slight Correspondence to: in response to heat, and Dr Marco dell'Omo, impairments tactile, Institute of Occupational pain stimuli in all 10 fingers. Muscular Medicine, University of was normal in both hands. Phalen's Perugia, Via E dal Pozzo, strength 06100 Perugia, Italy. Keywords: carpal tunnel syndrome; ulnar nerve; occu- and Tinel's signs were absent. Accepted 13 October 1994 pational Electroneuromyography explored the opponens pollicis, adductor pollicis, abductor digiti minimi, flexor carpi radialis, brachiora- dialis, and pedidius muscles, and the median, Electrophysiological study of the median and ulnar nerves ulnar, radial, and peroneal nerves. No sponta- Distal latency neous activity potentials were evident in any Stimulation Registration muscle and voluntary activity produced an Nerve site site (muscle) May 1993 (ms) Aug 1993 (ms) interference type trace with normal motor R median Wrist Opponens pollicis 11 0 8-4 unit potentials. Median and ulnar nerves Elbow Flexor carpi radialis 3-0 showed considerable bilateral R ulnar Wrist Abductor digiti minimi 2-8 2-5 (table) Wrist Adductor pollicis 13-0 6 6 increases in distal motor latency at the wrists. L median Wrist Opponens pollicis 10 4 5 5 in the radial and Elbow Flexor carpi radials 3-4 Motor conduction velocity L ulnar Wrist Abductor digiti minimi 4-6 5-5 peroneal nerves was normal. Wrist Adductor pollicis 18-0 9-8 Standard radiological studies of hands, R = right; L= left. wrists, elbows, and shoulders were normal. 212 dell'Omo, Muzi, Cantisani, Ercolani, Accattoli, Abbritti Magnetic resonance (MR) imaging showed indicative of involvement of the superficial no morphological abnormalities in the sensory branch. The notable increase in distal wrists. latency in the adductor pollicis muscle Occup Environ Med: first published as 10.1136/oem.52.3.211 on 1 March 1995. Downloaded from Electrocardiography, chest radiographs, compared with levels in the abductor digiti routine blood tests, erythrocyte sedimentation minimi indicated damage to the deep motor rate, glycaemia, urine analysis, rheumatoid branches in the palm of the hands after the factor tests, thyroid hormone, and thyrotropin muscles of the hypotenar eminence had been concentrations were all normal. supplied. The data suggested also demyelini- We suspected that the patient's job may sation of the ulnar nerves inside Guyon's have been associated with the syndrome, so canal. we advised him to suspend his activity. Three Many systemic diseases and local factors months later, he reported a significant can determine the onset or worsening of the improvement in the paraesthesia in the fourth CTS or Guyon canal syndrome.' In this and fifth fingers of both hands. Electro- patient, the case history, clinical, and labora- neurography showed distal motor latencies tory findings excluded any endocrine or were significantly improved bilaterally (table) metabolic pathology that could be linked to in both the ulnar and median nerves. compression neuropathy. Magnetic resonance imaging is a useful aid to diagnosis; it provides a well defined picture of the bones Discussion and soft tissues of the hand and wrist,5 but in At the wrist the median nerve passes through our patient it did not show any anatomical the carpal tunnel and the ulnar nerve through alteration in the carpal tunnels or Guyon's Guyon's canal. The carpal tunnel is bounded canals. by the carpal bones and is roofed by the trans- Both the CTS and neuropathies of the distal verse carpal ligament. Guyon's canal, which is ulnar nerve may be work related. Increased medial to the carpal tunnel, is bounded poste- risk of CTS has been documented in grocery riorly by the transverse carpal ligament, anteri- checkers, packers, electronics assembly work- orly by the volar carpal ligament and by the ers, butchers, and garment workers,267 flexor carpi ulnaris tendon, medially and whereas neuropathy of the ulnar nerve has proximally by the pisiform bone and laterally been found in workers who use hand tools, and distally by the hook of hemate. In these cyclists, musicians, video game players, and two canals, a reduction in volume and an computer operators.'68 We have found no increase in internal pressure may cause report of neuropathy due to compression of entrapment neuropathy.' The ulnar nerve the ulnar and median nerves in a parquet may also be damaged distally, after its exit floorer. The CTS may also be associated with from Guyon's canal.' neuropathy of the ulnar nerve at the wrist9 In this case, paraesthesia affected all 10 and may be bilateral in some categories of fingers, which suggests simultaneous bilateral workers.'0 Such a severe, bilateral involve- involvement of the ulnar and median nerves. ment of the median and ulnar nerves is Phalen's and Tinel's signs were absent, but a unusual. bilateral CTS could not be excluded as The aetiological agent was, in our view, http://oem.bmj.com/ neither sign has a high diagnostic validity.4 repeated wrist and palm trauma. When at The neurophysiological investigation con- work, after having glued and laid the wood firmed severe bilateral distal impairments in blocks, the floorer used the right wrist and the median and ulnar nerves that caused a palm to hit and press them into place in one notable increase in motor latencies. The site direction and then the left wrist and palm to of median nerve lesion was most probably the position them in the other. Hands were held carpal tunnel. To identify the site of the ulnar in dorsal flexion, which increases pressure on October 2, 2021 by guest. Protected copyright. nerve lesion was more difficult because of the inside the semirigid carpal tunnel,"I and prob- anatomical complexities and differences in the ably contributed to the genesis of lesions. distal tract between people. Inside Guyon's Another pathogenic factor could have been canal the ulnar nerve divides into the superfi- the vibrations to which the floorer was cial and deep motor branches. The superficial exposed when using the electric floor sander branch is predominantly sensory and extends and polisher. Experimental data indicated to the ulnar surface of the hypotenar emi- that vibrations cause perineural oedema, nence, the fourth and fifth fingers, whereas which may, if the vibratory stimulus persists the deep branch supplies the hypothenar mus- over time, become chronic and lead to the for- cles (abductor, opponens, and flexor brevis mation of fibrous tissue.'2 The consequent digiti minimi).