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Protrusion of the First Thoracic Disk P.J. Hamlyn, T. Zeital, and T.T. King The London Hospital and Kiel University, London, England
Hamlyn PJ, Zeital T, King TT. Protrusion of the first thoracic disk. Surg Neurol 1991;35:329-31.
A case of lateral prolapse of the T-l/T-2 intervertebral disk is presented. The patient complained of pain radiating down the medial aspect of the forearm into the little and ring fingers. This was associated with a subjective sensory loss in the same distribution, intact reflexes, and no long tract signs. Oculosympathetic paralysis was not present. Twelve cases have been mentioned in the literature, only eight of which contain details of the neurological findings. The varied findings in these cases are also reviewed, and it is noted that unless radiological examination includes the upper thoracic spine in cases of brachial neuralgia, these lesions will be missed. KEY WORDS: Brachialgia; First thoracic disk; Thoracic disk protrusion
It is estimated that 0 . 2 5 % - 0 . 7 5 % of all clinically significant prolapsed intervertebral disks occur in the thoracic region [2,6]. Reviewing the literature on thoracic disk protrusions, Arce and Dohrmann [2] found that 75% of these occur below the T-8 level, with only eight cases (3%) occurring at the T-l/T-2 level. In the largest single series of thoracic disk protrusions to date, Russell [8] found no cases of T-l/T-2 prolapse in a total of 67 cases. The present authors have found 12 cases mentioned in both the cervical and thoracic disk literature, eight of which detail the neurological findings [ 1,3-7]. Symptoms relating to both long tract and root compression have been described, along with interruption of the sympathetic outflow at T-1 with a resultant Horner's syndrome. Case
Report
A 72-year-old white woman presented in December 1988 with severe neck pain that radiated to the right
Address reprint requests to: Mr. P.J. Hamlyn, Department of Neurosurgery, The London Hospital, London El, United Kingdom. Received June 25, 1990; accepted October 9, 1990.
© 1991 by Elsevier Science Publishing Co., Inc.
shoulder and down the inner aspect of the arm and forearm to the little and ring fingers. Associated with numbness and dysesthesia, the pain was exacerbated by right lateral flexion of the neck and coughing. The symptoms were of 1 month's duration and had begun spontaneously. The other arm, trunk, and legs were not affected, there was no bladder or bowel dysfunction, and no previous relevant history. No relief was obtained from analgesics and a collar. Neck movements exacerbated the pain and sensory examination revealed reduced perception of both light touch and pinprick over the inner aspect of the arm, forearm, and the little and ring fingers. The left supinator, triceps, biceps, and other reflexes were normal. There was slight weakness of the intrinsic muscles in the left hand compared with the right. Cranial nerve examination, including the pupil size and reflexes, was normal. There were no neurological signs in the other arm, trunk, or legs. General examination was unremarkable. Plain x-ray films of the cervical and thoracic spine showed mild degenerative changes only. Myelography suggested the presence of an anterolateral extradural impression at the T- 1/T-2 level, although this was poorly seen. Computed tomography (CT) scan at this level clearly demonstrated the lesion suggesting lateral prolapse of the intervertebral disk (Figure 1). The remainder of the study was normal with no other cervical or thoracic pathology being seen. The cerebrospinal fluid was clear, acellular, and normal biochemically. No growth was obtained on culture or abnormal oligoclonal proteins detected on electrophoresis. Hematology, including erythrocyte sedimentation rate and a chest x-ray, and electrocardiogram were normal. Surgery was performed in the prone position with a midline posterior incision and stripping of the paravertebral muscles on the left. The first thoracic spinous process was identified with peroperative x-ray films and a limited fenestration fashioned with a high-speed air drill laterally, between the T-1 and T-2 laminae. Tight compression of the T-1 root was found with lateral rupture of the disk into the canal anterior to the root. There was no sign of spinal cord compression and the prolapsed 0090-3019/91/$3.50
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Figure 1. C T scan following myelography u'ith arrow indicating the lateral protrusion of the first thoracic intervertebra/ disk.
material was removed following which the disk space was cleared in the usual way. The patient made an uneventful recovery and was immediately relieved of her pain, although the sensory disturbance persisted for several months. Postoperative x-ray films confirmed that the procedure had been carried out at the correct level. Six months following the surgery she was symptom-free and neurological examination was normal.
Discussion Prolapse of thoracic intervertebral disks is uncommon and particularly unusual in the upper thoracic levels [2,6,8]. The neurological descriptions of the eight cases available from the literature of 12 herniations at the T1-2 space show variation in both symptoms and signs [1,3-5,7]. The case Arseni and Nash [3] described had gradually progressive spasticity, truncal hypesthesia, and sphincter disturbance following trauma and was found to have a central protrusion. The result of a posterior, transdural removal was poor. The remaining seven cases had lateral protrusions and there was no associated trauma. Pain radiated from the neck to the shoulder, anterior chest wall, and interscapular regions, as well as the medial aspect of the arm and forearm. In two cases the initial suspicion was of cardiac
Hamlyn et al
pathology [ 1,4], and in the four described by Murphey et al [7], the pattern resembled that of C-8 involvement. Sensory loss affected the medial aspect of the arm and forearm; however, no changes were detected by Gelch [4] or Lloyd et al [5]. In contrast to the present case the little and ring fingers were spared. Motor deficits were restricted to the intrinsic muscles of the hand, except in one case in which the wrist extensor and triceps were also affected [1]. As with the subject of this report, the deep tendon reflexes were normal. H o m e r ' s syndrome, which resolved following surgery, was a feature of the two cases described by Gelch [4] and Lloyd et al [5]. O f the four cases described by Murphey et al [7], at least one was affected and possibly all of them were. As with the present case, however, Alberico et al [1] found no occulosympathetic involvement. The variations in symptoms and signs produced by this lesion presumably reflect the degree o f prolapse and the root distribution of the C-8 and T-1 dermatomes and occulosympathetic outflow. Where detailed radiological examination of patients with brachial neuralgia does not routinely include the T-l/T-2 disk, these lesions will presumably be missed. This may in part be responsible for the infrequency with which they have been reported. For central thoracic disk herniations, the choice of surgical approach would now be of an anterior transthoracic or lateral costotransverse route. However, as in the present case, lateral protrusions have been successfully excised through simple fenestrations [ 1,4]. While CT imaging was available only to one previous author [1], it clearly facilitates the planning o f such surgery. In conclusion this unusual condition may present with signs of either long tract or root compression. With lateral protrusions the associated neurological deficits may be slight, leading to confusion with cardiac and other pains. The neurological findings are often identical to that of C-8 compression, although, when present, Horner's syndrome will provide a distinguishing feature. At the T-1 level simple fenestration may afford safe access to lateral protrusions with no spinal cord involvement, and CT scanning provides valuable information for the planning of surgery. Radiological examination of patients with brachial neuralgia should include the T-l/T-2 disk.
References 1. Alberico AM, Sani KS, Hall JA, Young HF. High thoracic disc herniation. Neurosurgery 1986;19:449- 51. 2. Arce CA, Dohrmann GJ. Thoracic disc herniation. Surg Neurol 1985;23:356-61.
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3. Arseni C, Nash F. Thoracic intervertebral disc protrusion. J Neurosurg 1960;17:418-30. 4. Gelch MM. Herniated thoracic disc at the T1-2 level associated with Horner's syndrome. J Neurosurg 1978;48:128-30. 5. Lloyd TV, Johnson JC, Paul DJ, Hunt W. Horner's syndrome secondary to herniated disc at T 1-T2. AJR 1981);134:184- 5.
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6. Love JG, Schorn VG. Thoracic-disk protrusions. JAMA 1965; 191:627-31. 7. Murphey F, Simmons JCH, Brunson B. Clin Neurosurg 1973; 20:9-17. 8. Russell T. Thoracic intervertebral disc protrusion: experience of 67 cases and review of the literature. BrJ Neurosurg 1989;3:153-60.