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The melanotic neuro-ectodermal tumour of infancy is an uncommon benign tumour of neural crest origin occurring in infants with a predilection for the anterior maxilla. This lesion shows a good response to conservative surgical excision with few recurrences but it should be followed up for long periods of time because of the rare malignant change possible in the tumour.
A 17-year-old female presented with a very rare case of primary Ewing's sarcoma of the skull involving the occipitotemporal region. Systemic examination found no evidence of metastasis. The tumor was surgically removed, and the patient underwent radiotherapy and chemotherapy. Fourteen months after surgery there has been no recurrence of the tumor. Cranial primary Ewing's tumor has a good prognosis after radical surgery and adjuvant therapy.
A 5 month old boy was found by his mother to have a bony mass behind the left ear which extended intracranially on MRI scan. At surgery it was entirely extradural in location. Microscopically, a biphasic appearance consisting of large pigmented cells arranged into tubules and small nonpigmented basophilic cells arranged into nests gave rise to a diagnosis of melanotic neuroectodermal tumour of infancy [MNETI]. One year after a wide local excision the patient is tumor-free and developing normally. The prognosis for MNETI in general is excellent with no requirement for additional radiotherapy or chemotherapy.
Plasmacytoma originating in the cranial bone is a rare disease. A report is presented of a case of plasmacytoma originating in the parieto-occipital region. The patient was a 62-year-old male with palpation of a parieto-occipital mass as chief complaint. He showed no neurological deficit. Ig-G in the serum was 2240 mg/dl, and M-protein (n-type) was demonstrated in the serum. Bence-Jones protein was negative and bone marrow was normal. Skull X-ray showed osteolytic change in the parieto-occipital region. CT scan and MRI demonstrated a markedly enhanced mass extending from the epidural to the subcutaneous space at the parieto-occipital region. Common carotid angiography showed remarkable tumor stain flowing from the occipital artery, the superficial temporal artery, and the middle meningeal artery. Following embolization of the bilateral occipital artery, parieto-occipital horse shoe scalp incision was done. The tumor was elastic soft and bled easily around the margin of destroyed bone. Subtotal removal of the tumor was accomplished. The removed surgical specimen of the tumor was found to be plasmacytoma. The patient's postoperative course was favorable and no neurological deficit was found. Laboratory studies revealed a remarkable reduction of Ig-G in the serum to 1170 mg/dl. Six months after the operation, no signs of recurrence were seen on CT scan. Plasmacytoma originating in the cranial bone is so rare that only 18 cases have been reported to date. In these cases, laboratory studies have shown no evidence of anemia, Bence-Jones protein in urine, and abnormality of the bone marrow which are characteristic of multiple myeloma.(ABSTRACT TRUNCATED AT 250 WORDS)
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Two cases of cloverleaf skull syndrome are reported. The patients were born with trilobed deformity of the skull associated with synostosis of the lambdoidal, coronal, and sagittal sutures in Case 1 and of the lambdoidal suture in Case 2. Both patients had hydrocephalus, low-set ears, and ocular hypertelorism. Ventriculoperitoneal shunting had been performed for hydrocephalus in both cases in early infancy. Thereafter, the skull anomaly caused mental and physical retardation and elevated intracranial pressure. In both cases, surgery was successful in terms of cosmetic and neurological improvement. Both cases involved prominent midline crista formation of the skull over the posterior fossa, which steadily progressed during the first year of life and produced hydrocephalus, apparently by compressing or obstructing the aqueduct and/or the ostia of the fourth ventricle. Twenty-four cases of surgery for cloverleaf skull syndrome have been reported to date. Only Partington's types II and III were treated surgically, and patients with type III had more favorable outcomes than those with type II. However, these reports provide no clear-cut data that surgery significantly influences the outcome. The experience with the two cases reported here suggests the benefits of early shunting followed later by radical surgery.
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OBJECTIVE: An analysis of the distribution of stresses at the juvenile and adult cranial base after implementation of a rapid palatal suture expansion was the goal of this study. Of particular interest were stresses occurring near the cranial foramina containing vulnerable structures. MATERIALS AND METHODS: The stresses were simulated and analyzed using a finite elements model of the human cranial base. The model consisted of several skull bones (sphenoid, frontal bone, occipital bone, and the two temporal bones) with a total of 41,556 finite elements. To illustrate the differences between reactions in the juvenile and the adult, the differing bone elasticity was depicted as variations in the modulus of elasticity. RESULTS: At the juvenile cranial base only moderate stresses occurred during rapid palatal suture expansion, apparently precluding the likelihood of any serious complications in the area of the foramina. The situation in the adult, however, was different. Because of the reduced elasticity of the bony structures, considerable stress already occurred on light bending of the pterygoid process, especially in the area of the round foramen, the oval foramen, and the superior orbital fissure, all of which might lead to microfractures with injury of nervous and vascular structures. CONCLUSIONS: The lower the bone elasticity on carrying out a rapid palatal suture expansion, the more important safety measures are for protecting the cranial base. For this reason the pterygomaxillary connection should be severed on both sides in adults when carrying out a surgically assisted palatal suture expansion.
BACKGROUND CONTEXT: Patients with cervical myelopathy secondary to craniocervical instability commonly present with spinal cord compression secondary to a combination of static forces and gross instability. Craniocervical arthrodesis is therefore indicated in the treatment of the majority of these conditions. In order to facilitate arthrodesis, techniques for occipitocervical instrumentation have been developed. PURPOSE: To systematically review the anatomy, biomechanics, and practical considerations involved in posterior occipitocervical instrumentation. STUDY DESIGN: Retrospective literature review. PATIENT SAMPLE: Not applicable. OUTCOME MEASURES: Not applicable. METHODS: Retrospective literature review. RESULTS: The anatomic elements of the craniocervical junction include the occipital bone, occipital condyles, atlas (C1), and axis (C2). The occiput-C1 and C1-C2 motion segments possess unique mechanical properties. Occipitocervical instrumentation constructs are comprised of points of fixation and longitudinal elements, each with characteristic strengths and weaknesses. CONCLUSIONS: Analysis of the anatomy, available points of fixation, and the movements to be controlled leads to the choice of a longitudinal element which can control movement by incorporating the strongest points of fixation. By going through this process for each patient, an informed decision may be made regarding the optimal occipitocervical instrumentation construct.
OBJECTIVE: To design a new far-lateral transcondylar transtubercular keyhole approach assisted by neuro-navigation system according to the keyhole idea, and to explore the possibility of removing the occipital condyle and jugular tubercle precisely. METHODS: Navigation data were established on 8 cadaveric heads fixed by formalin and with their intracranial vessels perfused with colored silicone. Before the operation, circumscriptions of the occipital condyle and jugular tubercle were outlined with different colors in the navigation system in order to aid drilling them in operation. A 7 cm longitudinal "S" shaped skin incision was performed with its superior border 2 cm behind the middle point of mastoid and inferior margin at the level of C(2). After inverting the suboccipital muscles and exposing the far lateral part of the occipital bone, occipital condyle, hemilamina of C(1), vertebral artery and posterolateral portion of foramen magnum, a retro-condylar bone flap 3 cm in diameter was cut. Assisted by neuro-navigation, not only were the maximal angle of visual field measured before and after the 1/3 and 1/2 posteromedial occipital condyle removal respectively, but also the anatomic structures were observed and measured. RESULTS: The incision of the retro-condylar keyhole approach fully met the needs of the far-lateral transcondylar transtubercular keyhole approach; partial occipital condyle and jugular tubercle could be precisely drilled with the aid of neuro-navigation, thus avoiding the bewilder in drilling process; the maximal angles of visual field were 39.2 degrees +/- 3.29 degrees (before condyle drilled), 51.5 degrees +/- 2.45 degrees (1/3 condyle drilled) and 57.5 degrees +/- 2.66 degrees (1/2 condyle drilled) respectively, and there were significant difference among them (P < 0.01). CONCLUSION: It is feasible to perform the far-lateral trascondylar transtubercular keyhole approach; the maximal angle of visual field is obviously increased by drilling partial occipital condyle, and the middle clivus can be increasingly exposed through removal of jugular tubercle.
OBJECTIVE: To determine factors including treatment modalities which influence survival in patients with osteosarcoma of the head and neck. STUDY DESIGN: Retrospective clinicopathologic study of 27 patients with osteosarcoma of the head and neck. METHODS: The clinical charts and pathology slides were reviewed on 27 patients who had osteosarcoma of the head and neck between 1946 and 1998. The following variables were examined for their effect on survival: age of diagnosis, site of tumor, presentation, race, sex, prior radiation exposure, retinoblastoma history, margin status, and method of treatment. RESULTS: The average age at the time of diagnosis of the patients was 37.6 years (range, 7-82 y). The sex distribution was similar with 14 male and 13 female patients. Eight of 27 patients had osteosarcoma of the mandible, 9 of 27 had osteosarcoma of the maxilla and paranasal sinuses, and in 10 of 27 patients osteosarcoma occurred elsewhere, including the temporal bones, occipital bones, and orbit. The overall 2-year survival was 66% with a 5-year survival rate of 55%. CONCLUSIONS: Positive surgical margins and a high tumor grade were found to have a statistically deleterious effect on overall survival. There was no detectable effect on survival of age, race, sex, prior radiation exposure, tumor site, and tumor cell type. It was not possible to differentiate between the different adjuvant treatment modalities because of the small numbers in the study.
Hyperpneumatization of the temporal bone with extension into the occipital bone and even the parietal bones is a rare condition. According to a review of the literature, it mostly appears unilaterally in men and on the right side. Often it is discovered when complications like pneumatocele or pneumocephalus appear. The authors review and analyze all reported cases of hyperpneumatization, its symptoms, complications and treatment. We present a patient with extensive pneumatization found in the mastoid process, temporal bone, occipital bone and both parietal bones, who was discovered accidentally. The cause of the extension of pneumatization into the occipital and parietal bone is probably incomplete closure of the occipitomastoid synchondrosis and lambdoid and sagital sutures, which usually close in early adulthood and later, even in the 30s. Asymptomatic patients should be aware of possible complications, and in case of complications, operative therapy is often indicated.
STUDY DESIGN: Dorsal occipitocervical fusion is associated with a high rate of fusion failure and requires an additional surgical site for donor bone graft harvesting. In this series, an autologous occipital calvarial bone graft obtained from the same occipitocervical incision with contoured metal loops was used in 25 adults to achieve craniovertebral stabilization and fusion. OBJECTIVES: To study the use of autologous occipital calvarial bone grafts in occipitocervical fusion. SUMMARY OF BACKGROUND DATA: Cranial bone grafts have been used successfully in craniofacial reconstruction with good long-term results. In the plastic surgery literature, there are claims that membranous bone grafts are superior to endochondral bone grafts in fusions because of decreased resorption. In recent studies, results have shown successful use of calvarial bone in fusing the upper cervical spine in children. The use of autologous occipital bone in posterior occipitocervical fusions avoids many of the problems associated with traditional donor sites and provides a sufficient quantity of good quality bone for the fusion. This is especially true in the fragile rheumatoid arthritis patient with cranial cervical instability. METHOD: Split-thickness, autologous calvarial bone grafts with contoured loop and cable instrumentation were used for posterior occipitocervical stabilization and fusion in 25 patients, most of whom had rheumatoid arthritis. The calvarial bone graft was harvested from the occipital skull, using a microair impactor, and was secured next to the loop construct. After surgery, all patients were immobilized with external orthoses. RESULTS: None of the patients had hardware failure or complications from the occipital graft procurement. In 22 patients, good alignment, stability, and bony fusion were shown on radiographs. CONCLUSIONS: Occipital calvarial bone graft appears to work as well as other autologous corticocancellous bone grafts routinely used in posterior occipitocervical fusions.
Adequate choice of fixation technique at craniocervical junction depends on many factors: anatomical conditions at fusion site (e.g. anterior dislocations of the odontoid and rupture of the transverse ligament are contraindications for direct odontoid screw fixation. Sublaminar wiring and interlaminar clamps are useless in case of deficiency of posterior bony elements of C1 and C2 whether a result of laminectomy or destruction), bone quality (osteopenic bone is contraindication for screw techniques either transarticular or transpedicular). Enclosing of occipital bone into instrumentation may be difficult in wire and clamping techniques. In contrast screw techniques allow for easy grip the occipital bone. Screw techniques seem ideal in cases requiring enclosing of the occipital bone. The fusion rate at C1/C2 level seems independent of fixation techniques. When supplemented with external immobilization even biomechanically inferior wiring or interlaminar clamping provide nearly 100 rate of fusion. Screw techniques are technically demanding but they seem the method of choice when occipital bone is to be enclosed in instrumentation.
STUDY DESIGN: The significance of occipitoaxial angle in the development of subaxial subluxation after occipitocervical fusion was determined in a minimum 5-year follow-up study performed retrospectively. OBJECTIVE: To clarify the association between the position of the fixed occipital bone and axis and the development of subaxial subluxation. SUMMARY OF BACKGROUND DATA: There have been few reports describing the association between the position of fixation of the occipital bone and axis and subaxial lesion in occipitocervical fusion. MATERIALS AND METHODS: Thirty-eight patients with rheumatoid arthritis who underwent occipitocervical fusion for irreducible atlantoaxial dislocation were reviewed. The angle between the McGregor line and the inferior surface of the axis (O-C2) was measured in healthy volunteers and patients who had undergone occipitocervical fusion. The association between any changes in the alignment of the cervical vertebrae and the development of subaxial subluxation during follow-up periods was studied. RESULTS: The number of the patients in whom postoperative kyphosis and swan neck deformity developed was only five, but in four (80%) of them, retroversion of the occipital bone was used to increase the O-C2 angle. In 14 patients, in whom anteversion of the occipital bone against the axis was excessive, 12 (86%) patients experienced subaxial subluxation after surgery. In the patients in whom fixed O-C2 angles were in normal range, only one patient developed such abnormal changes in the middle and lower cervical vertebrae. CONCLUSION: It is necessary to give attention to the position of the fixed occipital bone and axis during procedures of occipitoaxial fusion for patients with rheumatoid arthritis.