Butterfly vertebra is a very rare anomaly, but can be associated with disabling disorders. Diagnosis is sometimes difficult if complete history and neurological examination were not undertaken, as illustrated by these two reports;
CASE REPORT 1
A 2 years and 6 months girl presented to the Paediatric Consultant Clinic having been referred from the Orthopaedic Clinic with a history of frequent tripping over and weak left leg since birth. She is the product of a full term spontaneous vertex delivery. Pregnancy was uneventful. Her birth weight was 3000 gm. She was admitted to SCBU with fever and was given one-week course of antibiotics. She made a complete recovery. She was breast-fed and her early developmental milestones were said to be normal. She smiled at 6 weeks, sat up unaided at 6 months and walked with a limp at 10 months. Her speech and language has been satisfactory. She is still not toilet trained. She is fully immunised. She is the 4th member of a family of 5.All of her siblings are normal. At presentation, she looked normal with no dysmorphic features. Physical examination revealed notable limp and was dragging her left leg when she walks. Her muscle tone, power and reflexes were reduced in her left lower limbs. She had no clonus and Babinski sign was negative. Sensation appeared to be intact so far. She has no abnormal signs over the spine. She was found to have an ejection systolic murmurs grade II maximum along the left sternal age and loud P2.Chest examination revealed prominent thoracic cage and pectus excavatum. Her abdominal examination was unremarkable. She has bilateral Pes Planus and prominent thoracic vertebra number 12. (picture 1&2)
Plain x-ray spine showed Butterfly vertebra (T12) .MRI of dorsolumber spine reports (radiologist’s report) “T12 butterfly vertebra.TheT11and L1 vertebrae are seen to project into the central T12 defect. There is diastematomyelia with the cord splitting into two near equal hemi-cords at around T11 level and reuniting at L3 level. There is an anteroposterior bony septum at L1 level splitting the lumber canal into near equal halves.L1spinous process is bifid. The cord is low lying and tethered at S1level.Lipoma of filum terminale is seen. There is lumber dural ectasia. The central cord is prominent at T8 to T10 level. No interspinal or pre/paravertebral collection is seen” (see figures 1-10).
Figure 1, 2, 3, 4, 5, 6: butterfly vertebra at T12.Diastematomylia T11-L3.Tethered cord S1
Figure 7, 8, 9, and 10: enlargement and malformation of the canal due to ductal ectasia
All of her haematological tests were normal including liver function tests.
Echocardiogram revealed a small ASD (ostium secundum type), of 14.4 mm and moderate pulmonary stenosis with a peak gradient of 32 mmHg. This little girl has already been referred to the neurosurgical department for evaluation. She is currently receiving physiotherapy.
CASE REPORT 2
A 54 year old Libyan male; University teacher has been suffering from low back pain since early adolesensce .His back pain is exacerbated by standing for long time and unlike other common causes of backache it is particularly eased by forward bending .His low back pain does not radiate to lower limbs. He is otherwise perfectly well and his general as well as his neurological examinations was unremarkable. He was found to have butterfly vertebra when he was investigated for polyarthropathy in the early seventies .It was confirmed that his arthropathies were due to early onset osteoarthritis. No degenerative changes were found at the level of the butterfly and the adjacent areas. The clinical picture is typical for lumbar stenosis (bending forward). The stenosis apparently between L5/S1 and the level of the butterfly vertebra is at L4. (See figure 11 - 13)
Butterfly vertebra is a rare malformation of the spine. Probably first described in 1844 in the 12th thoracic vertebra of a 55-year-old adult by Rokitansky (1850). It is classified as a congenital developmental anomaly in the early embryonic period resulting in a variety of vertebral body malformation. (1,2,3,4,5,6,7) Ruge.Wilts 1977; O’Rahilly et al 1983; Mann & Murphy 1990). Butterfly Vertebra usually occurs in the lumber and thoracic spine and males are generally more affected than females (2) Barnes 1994; Aufdenhide & Rodriguez-Martin 1998). The butterfly malformation may involve two adjacent vertebral bodies, but the neural arches of the affected vertebrae are usually intact. The two halves of the vertebral body are generally equal in size, but hypoplasia of one or both halves sometimes occure. Moreover, they may be displaced laterally or wedged anteriorly, so that butterfly vertebra can result in Kyphosis or scoliosis due to the diminished height of anterioly-wedged vertebral body. In these cases affected subjects are likely to have back pain after heavy lifting or carrying as suggested by Fisher & Vandemark (1945) Epstein (1955) and Barns (1994).
Midline spinal cord/vertebral skeletal defects, termed spinal dysraphism result from defective closure of the caudal neural tube. Abnormal neural tube closure beginning early in the embryologic sequence produces dysraphism states which involve both neural and skeletal elements (myelomeningocele), while late-occurring closure defects produce congenital anomalies restricted to the posterior elements of the vertebrae (spina bifida occulta).
Occult spinal dysraphism is a defect of intermediate severity in which vertebral anomalies are associated with underlying intraspinal pathology or developmental abnormalities, such as a hairy patch, skin tag, port-wine stain, haemangioma, and subcutaneous lipoma or sinus tract. Common intraspinal lesions include dermoid tumours, intraspinal lipomas and diastematomyelia. While some patients with occult spinal dysraphism may show signs of neurological dysfunction and talips equinovarus from birth, most develop symptoms insidiously at around 3 years of age, but many do not develop problems until school age or adolescence.
Tethered Cord Syndrome consists of low conus medullaris resulting from an intradural lipoma, a diastematomyelia, or adhesion, shortening, or thickening of the filum terminale. As a result, nerve roots; cauda equine and conus are adhered to the dura. Cutaneous signs are lacking in 50% of the cases. Signs and symptoms are variable depending on the complexity of the abnormalities. These can present in early infancy or become manifest in early childhood. The clinical syndrome includes low back pain, scoliosis, tiptoe walking, foot deformities, bladder dysfunction, lower extremity weakness and muscle atrophy. Objective finding may consist of decreased tone and deep tendon reflexes in lower extremities, patchy decrease in sensation, deepening of the arch and contractures of the toes. The diagnosis is made by neuroimaging, and surgical treatment aims to free the cord and nerve roots. Less complex lesions and early diagnosis and treatment carry a better prognosis.
The presentation of the two patients is clearly different. One is a child and has a clinical picture strongly suggestive of dysraphism. The constellation of radiological findings is clearly malformative, and the butterfly vertebra is only part of it.
In this young girl no cutaneous lesions were seen and because she has not been toilet trained yet, it was very difficult to make any comments on her renal functions although her blood and urine tests were normal. We were not able to find any association between butterfly vertebra, spinal dysraphism, heart lesions and thoracic cage deformity in any of the literatures that we have revised. The second patient has an acquired spinal stenosis, and the butterfly vertebra is an incidental finding and although the patient has osteoarthritic changes no degenerative changes were found at the level of the butterfly vertebra. We believe that in a patient with a butterfly vertebra and a clinical picture of dysraphism, investigations are indicated, mostly because of the clinical picture. When the butterfly vertebra is isolated radiological investigations are not needed.
|The authors wish to thank Dr.H.Bzaizi , Dr.L.Nejjar, Dr.N.Yahya and Dr.S.Al-Hmadi for their great support and attribution to the report. We would like also to acknowledge the radiology department at the Libyan Swiss Diagnostic Centre, Tripoli for the excellent MRI report and films.|