Biomedical subjects
Publications and source records attributed to H Mehdian.
Melorheostosis affecting the axial skeleton is a rare condition. We present a case affecting a single thoracic zygoapophyseal (facet) joint that proved to be a diagnostic challenge. CT, MRI and radionuclide imaging with surgical and histopathology findings are discussed.
The course of spinal accessory nerve in the posterior triangle, the innervation of the sternocleidomastoid and trapezius muscles and the contributions from the cervical plexus were studied in 20 cadaveric dissections. The nerve was most vulnerable to iatrogenic injuries after leaving the sternocleidomastoid. Direct innervation of trapezius by cervical plexus branches was noted in five dissections, whereas connections between the cervical plexus and the spinal accessory nerve were observed in 19 dissections. These were usually under the sternocleidomastoid (proximal to the level of division of the nerve in nerve transfer procedures). Although the contribution from the cervical plexus to trapezius innervation is considered minimal, trapezius function can be protected in neurotization procedures by transecting the spinal accessory nerve distal to its branches to the upper position of trapezius.
The principles of management of capitellar and trochlear fractures are similar to any other intra-articular fracture. Accurate anatomic reduction, rigid internal fixation, and early mobilization of the elbow are prerequisites for a good functional result. Small fragments with minimal subchondral bone, not amenable to rigid internal fixation, are best treated by surgical resection. This article outlines the diagnosis, treatment, controversies, postoperative results, and complications of these rare elbow fractures.
STUDY DESIGN: A rare case of thoracic hypokyphotic deformity secondary to prune-belly syndrome is presented. OBJECTIVES: To discuss the role of an intact abdominal musculature mechanism in maintaining spinal sagittal balance, and to present a case illustration of prune-belly syndrome. SUMMARY OF BACKGROUND DATA: There has been an ongoing debate concerning the integrity of the abdominal musculature unit in maintaining spinal support and stability. It is now believed that intra-abdominal pressure hitherto generated plays an important role in the stabilization of the spine. Congenital aplasia of the abdominal musculature, termed prune-belly syndrome, might therefore result in the loss of spinal function and stability. The literature also is reviewed for the incidence of spinal deformities related to this condition. METHODS: A unique case of prune-belly syndrome in a 33-year-old man with congenital aplasia of the abdominal musculature is presented. RESULTS: The patient exhibited loss of the spinal sagittal balance, with resultant development of a thoracic hypokyphotic deformity and thoracolumbar scoliosis. CONCLUSIONS: Scoliosis appears to be the most commonly reported spinal deformity. Unequal compressive forces on the vertebral endplates may be the proposed mechanism for the spinal deformities. Compensatory lumbar paraspinal overactivity resulting from the inability to generate normal intra-abdominal pressures because of a deficient abdominal wall musculature mechanism seems to be the plausible explanation for the observed thoracic hypokyphatic deformity.
An analysis of the propagation of a space-charge wave through the wiggler and axial magnetic fields of a free-electron laser is presented. The relativistic electron beam is contained within and only partially fills a cylindrical metallic waveguide. A theory is developed using lab-frame Maxwell and fluid equations in a form which is equivalent to the electrostatic approximation in the beam frame. The computational method of determining the dispersion relation is described and some numerical results are presented which illustrate effects arising from the wiggler and the partially filled waveguide.
A 10-year-old girl presented with a 1-year history of pain and stiffness in her neck associated with left shoulder and arm pain. This was found to be caused by an osteoid osteoma of the lateral mass of C5. Surgical excision of the tumour was performed through a posterior approach. Following surgery, the patient's pre-operative pain resolved. However, 3 months later she developed a recurrence of neck pain secondary to cervical instability. Further investigation revealed a grade II spondylolisthesis at the C5/6 level. A combined anterior and posterior fusion was performed and the patient's instability pain rapidly resolved. At her 18-months' follow-up a solid fusion was confirmed radiologically and the patient remained asymptomatic with no evidence of tumour recurrence. The purpose of this report is to highlight the difficulty in diagnosing this condition as well as to emphasise the surgical technique required. It would appear that excision of the lateral mass will result in instability. To prevent this, fusion of the spine should always be considered at the time of surgical excision of the tumour.
A 19-year-old boy with a painful thoracolumbar scoliosis was found to have an osteoblastoma of the body of T12. Excision of the tumour was carried out through a left thoracotomy approach and strut bone grafting was performed. Complete excision of the tumour was facilitated by intraoperative radiographs of the removed vertebra. Following surgery the patient's pain resolved completely and the deformity was partially corrected. Osteoblastoma of the vertebral body in the thoracolumbar region has not previously been reported. Diagnosis may be difficult unless the significance of the association between pain and the scoliosis is appreciated. The tumour is often not readily apparent on plain radiographs. Therefore, further radiological investigation in the form of a bone and CT scan is necessary to establish the diagnosis. Early excision of the tumour is essential to prevent a permanent structural scoliosis from developing.
Extensive spinal epidural abscesses (SEAs) carry a high mortality rate. Traditionally they are treated non-operatively with long-term antibiotics and/or surgical decompression, but there is a continuing debate as to whether they should be managed by emergency surgical decompression. However, such decisions are made in the light of the clinical setting. We report the successful management of a female patient who presented with features of upper cervical cord compression and later developed septic shock and multisystem failure. Surgical decompression of the cervical spine and irrigation of the epidural space with a paediatric catheter was performed followed by tricortical strut grafting and plating. At review, 36 weeks after surgery, the patient remained asymptomatic, having made full neurological recovery. The purpose of this report is to highlight the importance of emergency surgical intervention for extensive SEA in the presence of progressive neurological loss associated with multisystem failure.
We report a case of a hernia through the thoracolumbar fascia in a young adult male who presented with pain and swelling in the thoracolumbar region. Surgical repair of the defect was performed in the superficial layer of the thoracolumbar fascia and, 18 months following surgery, he remained asymptomatic. The purpose of this report is to make clinicians aware of a thoracolumbar hernia as a rare cause of back pain.
Von Recklinghausen's disease of the cervical spine is rare. Spinal deformities appear to occur only in peripheral neurofibromatosis as opposed to central neurofibromatosis, and such deformities include non-dystrophic and dystrophic changes. We describe two patients with neurofibromatosis of the cervical spine who were subjects of simple trauma, one of whom demonstrated dystrophic and the other non-dystrophic changes. The first presented with acute upper cervical spine instability and subluxation, the second with cervical myelopathy. The purpose of this article is to heighten the physician's awareness that such patients have inherent pathology in the cervical spine such that simple trauma can have serious neurological consequences.
We describe an unusual injury to the upper cervical spine sustained during ejection from an aircraft. MRI provided an accurate and direct diagnosis of the severe ligamentous injuries.
We report on a 19-year-old man with a 6-month history of pain and stiffness in the upper cervical region who proved to have a lytic lesion affecting the anterior and posterior elements of C2-4, causing a severe gibbous deformity at C3. The tumour was excised through a posterior approach, and spinal fusion with instrumentation was performed. Two weeks later, through a right-sided, anteromedial approach, the remaining tumour was excised, and the spine was reconstructed with tricortical iliac bone as a strut graft. The patient was placed in a Minerva jacket for 3 months, during which time a solid fusion was obtained. The histological diagnosis was aneurysmal bone cyst. The patient has remained pain free and suffered no recurrence 2 and a half years after surgery. Involvement of several adjacent cervical vertebrae by an aneurysmal bone cyst is rare, and conventional treatment with curettage and bone grafting is most likely to carry a high rate of recurrence and spinal instability. We recommend complete excision of the tumour in a combined staged procedure and instrumentation to prevent recurrence and avoid instability.
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Severe spondylolisthesis produces a kyphos at the lumbosacral junction. Reduction can be complicated by injury to the cauda equina. To prevent this, a posterior decompression and fusion is carried out before a slow reduction in extension. An anterior fusion with internal fixation then locks the reduction. Using these principles, a good reduction was achieved in 20 of 22 patients. Only two patients suffered a permanent neurologic deficit consisting of slight loss of ankle dorsiflexion. Severe spondylolisthesis can be safely reduced by this method.
We have carried out a biomechanical study to investigate the effect on flexion, extension, and rotation of seven systems of fixation on five cadaveric lumbar spines. Pedicle fixation proved the most effective method to restrict these movements. Facet screw fixation was also successful. Harrington distraction rods, the Hartshill rectangle and the Luque technique, although restricting slight flexion and extension, exerted little control over rotation. We conclude that pedicular fixation and facet joint fixation provide the greatest overall stability and might, therefore, be the best systems to consider for multilevel fusions in the lumbosacral region.
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We present a 26-year-old athlete with severe low back pain associated with a fracture of a lumbar pedicle and contralateral spondylolysis. The difficulties of diagnosis are discussed together with the subject of segmental pain referral. A technique of operative management is described involving instrumentation of the symptomatic level alone.
We report the technique and early results of the Dwyer-Hartshill method for segmental fixation of the spine. This uses pedicular screws wired to a rectangular frame and is indicated after laminectomy.