alkaptonuria ( aku ) is a rare hereditary autosomal recessive disease characterized by a defect in the gene which codes for homogentisate-1 , 2 dioxygenase resulting in the metabolic disorder of the aromatic amino acids , phenylalanine and tyrosine7 ) .
the enzyme - homogentisic acid oxidase catalyzes the conversion of homogentisic acid ( hga ) to maleylacetoacetic acid , and its absence leads to increase in hga accumulation in the body
. some of the excess hga excretes through the urine which turns dark on exposure to oxygen or alkalization occurs .
rest of accumulated hga oxidizes initially , and deposits within the connective tissue irreversibly and subsequently turns into melanin - like pigment .
it occurs especially in the cartilage of the joints and in the intervertebral discs , which is named as ochronosis1114 ) .
ochronosis not only affects the cardiovascular , genitourinary and respiratory systems , but also results orthopedic disorders like spondylosis and arthropathy .
the disease progresses from simple alkaptonuria to alkaptonuric ochronosis , leading to ochronotic arthropathy10 ) .
cervical myelopathy is usually due to degenerative changes in the spine with the osteophytes from the posterior part of the vertebral body and uncinate process encroaching upon the neural canal .
numerous reports on the successful management of ochronotic arthropathy of the peripheral joints like the knee and hip joints using total joint replacement .
however , there is a paucity of reports that have shown successful surgical intervention for spinal especially cervical spine involvement . in this paper
, we report a woman patient suffering from ochronotic spondylosis who was diagnosed during the late course of disease once the spondylitic myelopathy had set in resulting in increased neck and back pain , and associated with walking trouble and hands clumsiness .
a 62-year - old woman was admitted in the hospital in june 2011 , with a diagnosis of cervical spondylotic myelopathy . the patient began to experience neck and back pain with stiffness 7 years ago .
the symptoms developed slowly , until the gait disturbance and hand clumsiness began to appear in 2010 .
however , her symptoms progressed and at the time of presentation she was wheel chair bound .
she did n't have any history of trauma with no relevant past medical or similar family history .
physical examination showed cyan pigmentation on the nose , sclera , and the ear auricle and also in other parts of the body ( fig .
there was kyphosis at the thoracolumbar segment , resulting in a restricted movement at neck and back .
the grip - and - release test was 8 movements at both hands in 10 seconds , which was obviously inferior to the normal criterion of above 20 movements .
paresthesia on both hands and radial side of the left forearm and no motor weakness was observed .
ct scans indicated multilevel degenerative disc disease from cervical to lumbar spine , including narrowing , calcification , osteophytosis and vacuum phenomenon ( fig . 2 , 3 ) .
mri showed the cervical spinal compression in multi - segment by disc extrusion and ligamentum flavum redundancy simultaneously ( fig .
4 ) . as the color of the patient 's urine turn to dark after exposure to air after two hours
so , we confirmed the presence of alkaptonuria . as the patients ' cervical spine had normal lordosis and multi - level stenosis , we performed the modified laminoplasty .
this involves c3 laminectomy , c7 upper semi - laminotomy , and c46 open - door laminoplasty with implantation of man - made coral bone interposition .
this was in contrast to the conventional cervical laminoplasty technique that involves a laminoplasty from c37 completely . during the operation
, the ossificated nuchal ligament and the ligamentum flavum between c23 were stained black in color due to the deposition of the oxidized hga pigmentation ( fig .
the cervical joa score improved from 7 preoperatively to 9 at discharge and reached 11 at one year postoperatively .
she was satisfied with the treatment although she had difficulty in climbing stair case without crutches .
the cervical spondylotic myelopathy ( csm ) is not an uncommon condition in the spinal area , which follows a protracted clinical course consisting of a longer period of relatively stable symptoms punctuated by exacerbation of variable duration . for patients with moderate to severe symptoms ,
the surgical intervention should be considered as a possible procedure to prevent further neurologic deterioration and create a chance for recovery from myelopathy4512 ) .
aku , with its sequel ochronosis is a rare disease caused by an inborn deficiency of hga oxidase .
although there are symptoms that may give instant clue to the diagnosis like the urine turns to dark on exposure to air and discoloration on sclera , jowl , as well as in the underwear , the patients can often neglect the symptoms and appear at late in the course of disease24 ) . in few cases
it may be neglected until fourth or fifth decade when the symptoms secondary to ochronosis develop and the patients report to physicians .
the disease affecting the spine follows a chronological sequence , the patient usually first suffer from ochronotic spondylosis which is accompanied with the peripheral joint arthropathy1 ) , and it progresses to cervical spondylotic myelopathy which warrants surgical intervention .
the initial complaints usually include low back or neck pain with stiffness , and occasionally sciatica resulting from disc protrusion6 ) .
the characteristics of ochronotic spondylosis are multiple disc space narrowing , vacuum phenomenon and calcification in a water - like pattern due to the sparing of the central nucleus pulpous39 ) .
current literature has rarely reported the involvement of the cervical spine and consequent spinal cord compression requiring surgical intervention . in the present case report
, findings from the mri on the cervical region revealed that the redundant ligamentum flavum appeared to be the main cause behind the cord compression .
this could be secondary to the fact that the hga could bind irreversibly by a process of polymerization and oxidation to connective tissue collagen .
this prevents the collagen cross - link formation , which leads to the abnormality of the ligamentum flavum3814 ) . in view of the findings from mri
, we modified the standard technique to perform a modified cervical laminoplasty , which can permit extensive decompression through posterior expansion of the canal while continually maintaining cervical alignment and stability through the preservation of the posterior elements .
nowadays , all the available methods are only symptomatic for the early - stage , such as dietary restriction of tyrosine and more intake of vitamin c by its antioxidant effect , etc313 ) .
although the ochronotic arthropathy can severely handicap the patient because of its involvement in the spine and other joints , this incidence is quite rare .
cervical laminoplasty is often the procedure of choice given the fact that the involvement is extensively causing multilevel compression .
aku is a rare metabolic genetic disorder that is caused by the deficiency of homogentisic acid oxidase , affecting multiple organ systems in the body .
a typical cervical spondylotic myelopathy due to the ochronotic arthropathy of the cervical spine was reported in this paper , and a modified laminoplasty proved to be the appropriate treatment that yielded satisfactory result .
 ochronosis is a musculoskeletal manifestation of alkaptonuria , a rare hereditary metabolic disorder occurs due to the absence of homogentisic acid oxidase and leading to various systemic abnormalities related to deposition of homogentisic acid pigmentation ( ochronotic pigmentation ) . 
 the present case reports the clinical features , radiographic findings , treatments and results of a cervical spondylotic myelopathy woman patient due to the ochronotic arthropathy of the cervical spine . 
 the patient aged 62 years was presented with gait disturbance and hand clumsiness . 
 physical examination , x - rays , computed tomography and lab results of the urine sample confirmed the presence of ochronosis with the involvement of the cervical spine . 
 the patient underwent a modified cervical laminoplasty due to multi - segment spinal cord compression . 
 the postoperative follow - up showed a good functional outcome with patient satisfaction . 
 the present study concludes the conditions and important diagnostic and surgical aspects of a patient . 
 it is necessary to identify the condition clinically and if cord compression is observed , appropriate surgical interventions needs to be instituted . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION