Unintentional subdural catheter placement during labor analgesia shows typical radiological pattern but atypical response to the Tsui test.

Subdural injection may be associated with abnormally extensive or limited spread of local anesthetics during neuraxial anesthesia. This complication is difficult to diagnose clinically. Radiological imaging is the gold standard for confirming the location of subdural catheter, but electrical stimulation of the catheter has also been described as a useful diagnostic tool. We present the case of an obstetric patient with unintentional subdural catheter placement that presented as a failed epidural block associated with severe upper back and scapular pain on catheter injection. Electrical stimulation of the catheter did not elicit muscle contractions until a current of 4 mAmp was attained, which is the response pattern of epidural placement. Subdural location of the catheter was subsequently confirmed by contrast radiography. This case adds to the evidence that subdural catheters are difficult to identify clinically, and that electrical stimulation may not differentiate them from epidural catheters.

Nasopharyngeal liposarcoma MRI imaging features and a review of the literature.

We present a case of liposarcoma in a 37-year-old female with a chronic history of nasal stuffiness. MR imaging revealed a fatty lesion in the nasopharynx. Subsequent tissue sampling and histopathology demonstrated features consistent with a liposarcoma.

Conservative management of acoustic neuromas.

The results of this study and others document the biologic behavior of acoustic neuromas. In view of the evidence presented, which describes both variable rates of individual tumor growth and spontaneous regression in size, it would seem prudent that before selecting a nonsurgical treatment modality, the growth rate for the particular tumor in question should be established. To date, none of the literature that addresses the use of focused irradiation has attempted to do so. Our study as well as those of others suggests that the growth rate of acoustic neuromas becomes predictable over time. Based on this observation, a conservative (nontumor excision) management strategy is proposed for selected individuals. Patients to whom this management philosophy has been recommended or who themselves have chosen this option are seen twice yearly. Each visit consists of a thorough neurotologic examination as well as high-definition CT or MRI. Careful comparison of the clinical course as well as calculation of the tumor size is carried out in each instance. If the clinical course and rate of tumor growth remain unchanged over a 3-year follow-up, annual assessments are recommended. In the event of tumor enlargement, surgery may or may not be recommended, depending on the rate of growth and the age of the patient. Our experience suggests that a rate of growth equal to or exceeding 0.2 cm per year constitutes an indication for tumor removal.

Recurrence rates of acoustic neuroma in hearing preservation surgery.

Several authors have detailed the microscopic appearance of the acoustic neuroma/cochlear nerve interface. Others have highlighted the anatomic relationships existent between the lateral end of the internal auditory canal (fundus) and the otic capsule, as viewed from the posterior fossa. Based on these findings, several have suggested that hearing preservation attempts are likely associated with tumor persistence. They therefore question the feasibility of hearing preservation surgery. In this study, computerized tomography or magnetic resonance imaging was carried out on 28 patients having previously undergone excision of an acoustic neuroma with intraoperative sparing of the cochlear and facial nerves. Scans were done at least 5 years following surgery. Results of this study and a discussion of the literature follow.

Parotid gland and parapharyngeal space imaging--the surgical significance.

Wise head and neck surgeons, for whom parotid gland surgery constitutes a substantial portion of their case load, make full use of the radiologist and cytologist in arriving at a rational pre-operative diagnosis. They utilize the skill of these allied consultants to qualify (by histology) and quantify (by staging) diffuse and mass lesions of the parotid gland (and subjacent parapharyngeal space) in order to evolve an effective surgical, radiation or other treatment plan. They understand the basic principles of diagnostic imaging and apply them to the clinical problem at hand. They minimize diagnostic and intra-operative "surprises", reduce intra-operative and post-operative complications and generally have a more "informed" patient and patient's family. The purpose of this manuscript is to discuss a contemporary role for diagnostic imaging in neoplastic (and other) diseases of the parotid gland and subjacent parapharyngeal space. Not all lesions of the parotid gland require imaging, although a pre-operative clinical photograph, including evidence of facial nerve function, is always welcome. Other lesions may need diagnostic imaging, from simple to complex and sophisticated, depending upon the problem. Properly used, effective and selective diagnostic imaging can improve the surgeon's confidence by providing a more realistic provisional diagnosis and a better pre-operative staging process and treatment plan, thereby avoiding the surgically unexpected and facilitating prognosis.

A stereotactic system for guiding complex craniofacial reconstruction.

A stereotactic system has been designed to address the problem of achieving symmetry in complex and extensive craniofacial defects. Preliminary testing suggests that such a system, which allows for the intraoperative application of preoperative CT planning, will be useful in guiding the reconstruction of congenital or acquired bony time, is being used to investigate the correlation of intraoperative globe position following enophthalmos correction with long-term outcome, particularly as it relates to the size and location of the orbital defect, and the timing of the procedure.

Blow-in fractures of the orbit.

A blow-in fracture is an inwardly displaced fracture of the orbital rim or wall resulting in decreased orbital volume. The purpose of this study is to classify orbital blow-in fractures, describe the distinguishing clinical and radiologic features, and review the result of treatment. The series consists of 41 patients with blow-in fractures (34 males and 7 females). The mean age of the patients was 36 years. All were treated between 1979 and December of 1986 at Sunnybrook Medical Centre in Toronto. Clinical features of blow-in fractures were primarily related to the decrease in volume of the orbital cavity. Proptosis was a consistent finding, and in 27 percent of patients, the globe was further displaced in a coronal plane. Restricted ocular motility and diplopia were documented in 24 and 32 percent of patients, respectively. Fracture fragments displaced into the orbit resulted in globe rupture in 12 percent of patients, superior orbital fissure syndrome in 10 percent, and optic nerve injury in 1 patient. Blow-in orbital injuries were classified as pure fractures, consisting of an isolated blow-in of a segment of the roof, floor, or walls, or impure fractures, where the orbital rim itself was disrupted. In all cases, early decompression of the orbit and open reduction of fractures was necessary. Late sequelae of blow-in fractures were primarily related to injuries of intraorbital contents. Twelve percent of patients underwent enucleation and 8 percent reported persistent diplopia. Despite the presence of superior orbital fissure syndrome and complete ophthalmoplegia in 10 percent of patients, early orbital decompression resulted in resolution of nerve palsies in all but one patient.

MRI of the floor of the mouth, tongue and orohypopharynx.

Magnetic resonance is the imaging modality of choice for studies of the orohypopharynx, floor of the mouth, or tongue base. The superiority of MRI soft tissue contrast can demonstrate intra- and extraorgan spread of tumor beyond that of CT. Use of T1- and T2-weighted pulse sequences allows better discrimination of pathologic masses from fat or muscle than does CT. Multiplanar capabilities allow ease of examination in the preferred planes. Various sequences or planes of imaging may be chosen to tailor the examination to the anatomic region of interest. The use of Gd-DTPA with T1-weighted images should further improve diagnostic precision of tumor location and extension and may replace the need for the longer T2-weighted sequences. Gadolinium may help differentiate tumor recurrence from fibrosis in the post-radiation patient. New improvements in surface coil technology, motion and flow compensation imaging strategies, faster scan times, and spatial resolution will further advance MRI as the modality of choice for assessment of oropharyngeal, mouth, and tongue soft tissue masses.

Traumatic injuries of the paranasal sinuses.

High-resolution imaging, based on CT, has become the expected standard of imaging in severe sinofacial trauma. Imaging must include both bone and soft-tissue detail. Intracranial complications such as hematoma, contusion, and dural tear must be noted and followed appropriately. Early orbital assessment must be included to allow surgical decompression of hematoma or fracture reduction before irreversible changes to the visual pathway occur. Clinical assessment and initial, limited plain films offer an invaluable overview to set up priorities in resuscitation and subsequent direction for more detailed assessment by higher-resolution imaging. Complex facial fractures in noncontiguous structures are increasingly noted with high-velocity trauma. Open communication between clinician and radiologist should prevent only partial assessment of the true extent of involvement. Increasing use of CT (and possibly MRI in the near future) to follow persisting post-reduction complications (Fig. 14)--whether altered position of bone grafts or implants, ocular motility disorders and enophthalmos, or sinus obliteration or ablation--has resulted in the further need for the clinician and radiologist to understand each other's capabilities, in order to offer the patient maximum benefit from his or her imaging referral.

The radiology of sacral cysts.

The radiological findings in 10 patients with sacral cysts were retrospectively reviewed and classified. The cysts were an incidental finding on computed tomography (CT) in four patients. The expansion of sacral foramina or the sacral canal as seen on plain films suggested the diagnosis in three. In only two of the five patients who had myelograms did the cysts fill with contrast. In eight, CT showed remodelling and expansion of the sacral foramina, or the canal, or both, by a homogeneous mass with a density of 5-20 Hounsfield units. One of the patients underwent magnetic resonance imaging which confirmed that the lesion was fluid-filled. We found that sacral cysts can be either symptomatic or asymptomatic, that they may or may not communicate with the subarachnoid space, and that they have a characteristic CT appearance.

Contemporary imaging of parotid gland and parapharyngeal space.

Clinically, the parotid gland and associated parapharyngeal space can be assessed better using selective diagnostic imaging as an adjunct. It increases the effectiveness of management and the pretreatment staging of disease. This paper reviews the available specific imaging modalities (conventional x-ray films, contrast sialography, computed tomography, magnetic resonance imaging, ultrasonography, angiography and radionuclide scanning), their current indications and potential limitations.

Computed tomography of lingual thyroid.

The CT findings of a lingual thyroid are presented. A round, well-defined, homogeneously enhancing mass at the base of the tongue suggested the diagnosis leading to the confirmatory isotope scan.

Is no treatment good treatment in the management of acoustic neuromas in the elderly?

Two hundred twenty-eight patients with acoustic neuromas were seen between 1974 and 1985. Twenty-eight received no surgical treatment. Five patients who had undergone previous partial excision were excluded. The mean age was 71 years. The mean expected survival was 14.3 years. The mean follow-up interval was 51 months (range 12 to 120 months). All patients underwent at least two CAT scans (mean = 4). Tumor size ranged from 4 mm to 30 mm. Three patients underwent insertion of ventricular-peritoneal shunt for hydrocephalus (mean 16 months after presentation) and two patients partial tumor removal (mean 30 months after presentation). Tumor growth was measured in each patient using CAT scanning. Monitoring by clinical examination and regular CAT scanning is possible, but in this study 20% of patients required surgical treatment within one third of their expected survival time. This suggests that an expectant attitude for this group of patients may be a debatable form of management.

Epidermoid tumor: an unusual cause of ossification within the spinal canal.

Epidermoid tumors of the spinal canal are rare. We report two patients with intraspinal lesions and radiographically evident calcification. One proved to have an epidermoid tumor. Although the tissue diagnosis in the second was not definitive, it suggested an epidermoid tumor as well. Radiographically visible ossification or calcification has not been reported before in intraspinal epidermoids.

Radiologic assessment of acoustic neuroma in the elderly. Is no treatment good treatment?

Twenty-three elderly patients with acoustic neuroma have been followed conservatively (no treatment) for a mean of 3.8 years. Five patients subsequently required ventricular shunting. Two patients required partial excision of their tumors (one previously treated by shunting). Eleven patients who have required no treatment have no significant complaints. There was significant variation in tumor growth rates making predictability for surgical intervention hazardous. A mean growth rate of 0.22 cm/year was noted. Our statistics suggest tumor removal in healthy patients with larger tumors at time of presentation; in other patients, conservative follow-up may be more appropriate.

CT of myeloma involving the skull base.

We report three patients with myeloma involving the skull base. A large extracranial soft-tissue mass, intracranial extension, homogeneous enhancement, smooth margins, and bone remodelling were features common to the three lesions. In two patients the lesions extended into the orbit with one patient presenting with proptosis.

Transorbital intracavernous needle biopsy in painful ophthalmoplegia. Case report.

Painful ophthalmoplegia due to lesions in the region of the anterior cavernous sinus and superior orbital fissure may elude early diagnosis. Principal disease categories to be considered in patients with this complaint are neoplasm, vascular lesion, and inflammation. Although high-resolution computerized tomography (CT) may be helpful, definitive diagnosis frequently requires histological examination of tissue. In suitable patients this may be obtained by transsphenoidal or orbital biopsy. The orbital fine-needle aspiration technique has been recommended, but experience with this method is limited, and a definitive diagnosis cannot always be reached. The authors have established that, in suitable patients, the fine-needle aspiration technique with CT guidance may also be employed safely and effectively for lesions of the anterior cavernous sinus.

Multiple myeloma with initial presentation in the jaw: a clinical-pathologic discussion.

A 39-year-old white female presented with jaw pain initially interpreted as a manifestation of an odontogenic infection. Mandibular radiographs revealed lytic lesions suggesting a diagnosis of myeloma, which was subsequently confirmed by abnormalities in serum and urinary proteins and in bone marrow. Chemotherapy produced a transient response, but eventual relapse with extramedullary plasmacytomas and plasma cell leukemia led to death. The clinicopathologic implications of this case are presented and discussed.