A forty-five-year-old man was admitted to the hospital with a two-year history of progressive left-sided posterior thoracic and intercostal pain. Narcotic medications were necessary to relieve the pain, which had prevented the patient from playing and teaching the trumpet for six months. A review of the records revealed that the patient had been diagnosed as having type-I hereditary motor and sensory neuropathy (Charcot-Marie-Tooth disease) when he was nineteen years old. During adolescence, he had had a gradual onset of weakness and atrophy of both legs, atrophy of the intrinsic muscles of the hands, and a weak grip. As a teenager, he had been managed with a Milwaukee brace because of thoracic scoliosis. Additional details regarding the treatment with the brace were not available. When the patient was three years old, he had had a positive tuberculin test and had been hospitalized for one week. He was unable to provide additional details regarding the treatment. His father and paternal uncle also had Charcot-Marie-Tooth disease. He had had two episodes of pneumonia before the initial evaluation at our clinic and was being managed for mild essential hypertension at the time of admission.
Physical examination revealed a right thoracic kyphoscoliosis with a three-centimeter rib prominence. The patient walked with a wide-based gait and had a positive Romberg sign. There were no cerebellar signs, cranial-nerve and visual function were normal, and there was no evidence of optic atrophy or retinitis pigmentosa. He had symmetrical atrophy and weakness of the peroneal and anterior tibial muscles (grade 1 of 5), generalized weakness of the flexors and extensors of the toes of both feet, and normal function of the hips and the knees. He also had decreased sensation to pinprick, cold, touch, and vibration in both feet; symmetrical atrophy of the intrinsic muscles of both hands; and decreased sensation to pinprick, cold, and touch at the tips of the fingers and the thumbs. The ankle reflex and the radial reflex were absent bilaterally; all other tendon reflexes, the abdominal reflex, and the cremasteric reflex were present. The hematocrit was 37 per cent; the erythrocyte sedimentation rate was sixteen millimeters per hour; and the white blood-cell count was normal, which suggested that there was no underlying infection.
The right thoracic scoliosis measured 85 degrees, and the kyphosis measured 77 degrees. The motor-nerve-conduction velocity of the peroneal nerve was noticeably reduced. Computerized tomographic images showed sclerosis and extensive destruction of the seventh, eighth, and ninth thoracic vertebrae with massive osteophytosis and compression of the nerve roots on the left side (Fig. 1). A myelogram revealed partial blockage of the flow of contrast medium at the site of vertebral destruction (Fig. 2). The results of a previous biopsy, which had been performed under the guidance of computerized imaging, had been inconclusive. A second biopsy was performed at our institution with use of computer imaging, and histopathological examination of a specimen of tissue from the area of osseous destruction revealed fragments of sclerotic and reactive bone, degenerated intervertebral disc tissue, scar tissue, and fracture callus. There was no evidence of an infection or a neoplasm. The radiographic and histopatological findings suggested a neuropathic process.
Operative intervention was recommended because the patient had intractable, disabling, posterior thoracic and intercostal pain. He was managed with an anterior arthrodesis through a transpleural approach. A hypertrophic mass of disorganized bone was seen in the region of the seventh, eighth, and ninth thoracic vertebrae, and two of the intercostal nerves were incorporated in the mass. There was no fluid or overt evidence of infection. The osseous mass was resected to the posterior wall of the vertebral bodies, a trough was created for the placement of a rib graft, and an anterior arthrodesis was performed from the sixth to the ninth thoracic vertebra. This was followed on the same day by a posterior arthrodesis from the fourth thoracic to the first lumbar vertebra with use of Cotrel-Dubousset instrumentation and bone graft from the iliac crest. Postoperatively, the scoliosis measured 58 degrees.
Histopathological examination of the resected mass revealed fragments of cortical and cancellous bone; degenerated intervertebral disc tissue; and scarred collagenous and synovial tissue with foci of bone detritus, myxoid degeneration, and fibrocartilaginous metaplasia (Fig. 3). These changes were consistent with the rapidly progressive destructive process seen in a Charcot joint. There was no evidence of infection, granulomatous disease, or tumor.
Postoperatively, the patient had immediate relief of pain although the neurological status remained unchanged. On the tenth day, the patient was discharged wearing a spinal orthosis, which he used for three months. He had an occasional need for narcotic medication during the first postoperative month and used non-narcotic medication for an additional two months. Six months after the operation, he was working as a trumpet player, was teaching students, and had returned to his normal level of activity. At the two-year follow-up evaluation, the patient had no pain and radiographs showed a solid fusion with no additional neuropathic changes (Fig. 4).
Charcot first described neuropathic arthropathy in 1868 and suggested that there is a causal relationship between spinal cord lesions and Charcot joints. Kronig, in 1884, described spinal neuropathic arthropathy. Early investigators noted an association between neuropathic arthropathy and tabes dorsalis1,6,7,19,22,27, diabetes mellitus28, syringomyelia27, and spinal trauma2. Although neuropathic changes have been observed in the peripheral joints of patients who have Charcot-Marie-Tooth disease, we did not find any reports of neuropathic arthropathy of the spine in such patients in our review of the English-language literature.
Charcot-Marie-Tooth disease is part of a broad group of inherited neuropathic syndromes known as hereditary motor and sensory neuropathies9. Type I and type II are both inherited in an autosomal dominant mode. Type I is characterized by the onset of symptoms during adolescence. Weakness develops in the legs and then in the intrinsic muscles of the hand, and the motor-nerve-conduction velocity of the peroneal nerve is noticeably reduced. Our patient had type-I disease. Type II is the neural form of Charcot-Marie-Tooth disease and is characterized by normal or slightly decreased motor-nerve-conduction velocity. The onset of symptoms usually is delayed until the third decade of life. Five other types of hereditary motor and sensory neuropathies have been identified on the basis of clinical, genetic, electrophysiological, and neuropathological criteria. Type III is Dejerine-Sottas disease, the familial hypertrophic interstitial neuritis of infancy and childhood, which usually is inherited in an autosomal recessive mode. It is characterized by delayed walking in infancy followed by generalized weakness of the limb and the trunk during childhood. There is also weakness of all muscles of the limbs, particularly the distal muscles. Patients who have type-III disease are areflexic and may have sensory and truncal ataxia. Type IV is Refsum disease, which is inherited in an autosomal recessive mode. The diagnostic features of the disease include peripheral neuropathy, retinitis pigmentosa, cerebellar signs, increased levels of protein in the cerebrospinal fluid, and elevated levels of serum phytanic acid. Type V is characterized by spastic paraplegia and usually is inherited in an autosomal dominant mode. Type VI is similar to type I with optic atrophy. Type VII is similar to type I with retinitis pigmentosa9.
The loss of deep sensation makes joints susceptible to the effects of repeated microscopic trauma secondary to the activities of daily living; this results in destruction of the articular cartilage and narrowing of the joint space. The accumulation of debris consisting of fragmented subchondral bone and articular cartilage is accompanied by a hyperemic response with fibroblastic vascular proliferation12. Wirth et al. suggested that this local inflammatory response is not unique to neuropathic spinal arthropathy. Repeated microfractures adjacent to the joint produce additional disintegration of the joint. Despite the loss of sensation early in the course of the disease, the patient may have moderately severe pain that is often nocturnal27. During the late stages of the disease, the patient may complain of radicular pain due to the compression of nerve roots secondary to the collapse of vertebral bodies or the formation of osteophytes12; in addition, the patient may have back pain resulting from the altered stresses imposed on adjacent segments of the spine.
Previous investigators have reported on the prevalence of deformity of the spine in patients who have Charcot-Marie-Tooth disease. For example, Hensinger and MacEwen, reported kyphoscoliosis in seven (10 per cent) of sixty-nine patients who had Charcot-Marie-Tooth disease. Walker et al. noted scoliosis, kyphoscoliosis, or kyphosis in thirty-seven (42 per cent) of eighty-nine patients who had Charcot-Marie-Tooth disease. Spinal deformity was more common in girls and in children who had hereditary motor and sensory neuropathy type I; specifically, twenty-one of the thirty-seven patients who had spinal deformity were girls and thirty of these thirty-seven patients had type-I disease. The spinal deformity did not necessitate treatment in any patient. As that study did not include patients who were more than twenty-one years old, the authors did not discuss the natural history after maturity.
Daher et al. suggested that spinal deformities that are associated with Charcot-Marie-Tooth disease can be treated with the same techniques that are used to treat idiopathic scoliosis. In that study, four of twelve patients who had Charcot-Marie-Tooth disease and scoliosis were managed with posterior arthrodesis and Harrington instrumentation. The average preoperative scoliosis in these four patients was 55 degrees (range, 32 to 85 degrees), and the average kyphosis was 45 degrees (range, 35 to 55 degrees). The patients were kept recumbent for an average of five days after the operation and then were allowed to walk. Postoperatively, one patient was placed in a body cast, two wore an underarm brace, and one wore a Milwaukee brace. A pseudarthrosis developed in two of the four patients; one pseudarthrosis was asymptomatic and was not treated, and the other was repaired. As mentioned previously, Hensinger and MacEwen reported kyphoscoliosis in seven of sixty-nine patients who had Charcot-Marie-Tooth disease. Three of these seven patients were managed with posterior spinal arthrodesis during adolescence for a curve of 50, 60, or 70 degrees. No complications were noted. Postoperatively, the patients were immobilized in a corrective body cast and were kept recumbent for six months; they then wore another cast for an additional four months, during which time they were allowed to walk.
Most reports on arthrodesis of the neuropathic spine have been essentially case reports of small numbers of patients1,4,15,19,21,26. Brown et al. reported on fifteen patients in whom neuropathic spinal arthropathy developed in association with traumatic paraplegia. Eight patients had a spinal arthrodesis: six had posterior instrumentation with autogenous anterior strut-grafting, and two had anterior and posterior instrumentation with autogenous bone-grafting. All eight patients had a solid fusion. Of the seven patients who did not have an operation, two were asymptomatic, two refused the operation, and three were considering operative treatment. The patients who had been managed operatively had a number of complications, including two urinary tract infections, two superficial wound infections, and two instances of failed fixation. In three patients, changes consistent with Charcot arthropathy developed caudad to the level of fusion. Other investigators have suggested that inadvertent damage or denervation of the facets may result in additional degenerative changes17,23. This hypothesis is in agreement with the findings of Frymoyer et al., who reported that there was a high prevalence of degenerative changes cephalad to the level of fusion in patients who had had a spinal arthrodesis for reasons other than neuropathic arthropathy. Similarly, arthrodesis of the thoracolumbar spine has been shown to increase the risk of changes in the lower lumbar spine5,6,13,18,20.
On the basis of the history of a positive tuberculin test, we initially believed that our patient had tuberculosis of the spine. However, the histopathological findings from the second biopsy suggested a neuropathic etiology. Anterior and posterior spinal arthrodesis, after adequate débridement of the degenerated tissue, bridging of the gap with autogenous bone graft, and insertion of supplemental instrumentation to provide stability, resulted in osseous fusion of the involved vertebral segments. As the end point in this review was spinal fusion, we cannot comment on whether additional neuropathic changes will develop.