Edward R. Savolaine

Anatomy of the human lumbar epidural space: new insights using CT-epidurography

The anatomy of the lumbar epidural space was demonstrated in 40 patients by computed tomography (CT) examinations performed after epidural injection of noninonic radiographic contrast material into the sacral caudal canal via percutaneous catheter. Radiologic evaluation of the epidural space was performed to evaluate possible disc herniation or other pathologic encroachments on the epidural space. In all 40 patients, the examinations showed the posterior epidural space to be divided by the plica mediana dorsalis and an additional transverse connective tissue plane not previously described. The compartmentalized nature of the space may be, at times, responsible for entrapment and coiling of epidural catheters, despite satisfactory technical performance of catheterization for epidural anesthesia. Thirty-one of 40 patients demonstrated a greater amount of fatty tissue within the junctions of the posterior midline epidural connective tissue structures, producing a bulky triangular-shaped structure which might be an impediment to catheterization. The divisions of the anterior and posterior epidural spaces are seen to be more complex than previously described.

Posterior plating of the cervical spine.

A retrospective review of 36 patients treated with posterior cervical plating and autogenous iliac crest bone graft was performed to evaluate the results of posterior cervical plating in terms of fusion, outcome, technique, and complications. Numerous methods of cervical stabilization have been described with varying fusion rates and complications. Compared to wiring techniques, there is little information concerning the results of posterior cervical plating. Thirty-six patients with cervical instability underwent posterior plating with lateral mass screw fixation. Twenty-two had acute traumatic instability, four had late traumatic instability, six had metastatic disease, and four had postlaminectomy spondylotic instability. A Minerva brace was worn postoperatively for 3 months and fusion was assessed by bone incorporation on plain films, stable dynamic flexion-extension views, and absence of neck pain. Postoperative MRI and CT imaging was assessed in those patients who underwent these modalities. Fusion occurred at an average of 3 months in all patients. One patient demonstrated postoperative neurologic deterioration, but this resolved with subsequent decompression. Six patients had loosening of short, unicortical screws, but this did not affect the fusion result in five of these patients. The use of titanium implants allowed operative CT and MR imaging without the excessive artifact associated with stainless steel implants. Posterior cervical plating with lateral mass fixation and bone grafting offers a reliable method of achieving fusion. Bicortical lateral mass screws are less likely to loosen than unicortical screws, and no major complications occurred.

Scapulothoracic dissociation (closed avulsion of the scapula, subclavian artery, and brachial plexus): a newly recognized variant, a new classification, and a review of the literature and treatment options.

Scapulothoracic (ST) dissociation is a closed complete traumatic forequarter amputation manifested by a flail pulseless arm and well-defined roentgenographic findings. These roentgenographic findings were previously reported to be lateral displacement of the scapula and either acromioclavic-ular separation (17) or displaced clavicular fracture (20). In this paper we present four patients with ST dissociation who had a previously unreported combination of roentgenographic findings: lateral displacement of the scapula and sternoclavicular separation. Polytrauma was present in all previously reported cases of patients with ST dissociation. We present one patient, however, in whom ST dissociation is an isolated finding. A review of the literature, and a review of treatment options that includes some combination of amputation, shoulder arthrodesis, prosthetic fitting, and reconstructive tendon transfers, are presented.

Basal skull fracture with traumatic polycranial neuropathy and occluded left carotid artery: significance of fractures along the course of the carotid artery.

A patient who survived with traumatic multiple cranial nerve palsies and occluded internal carotid artery associated with a basal skull fracture that involved the carotid canal is described. A literature review indicates that a wide variety of injuries can occur to the carotid artery as it passes through a fractured skull base. Basal fractures involving the course of the carotid artery reflect a significant risk of carotid injury.

Coronal Fracture of the Body of the Hamate

Fractures of the body of the hamate are unusual. Eleven patients with coronal fractures of the hamate bone, all involving dislocation of the hamate-metacarpal joint, are reported. Routine roentgenograms were not helpful in delineating the presence of the injury in five patients; therefore, fracture diagnosis was not initially made in those patients. The average delay in diagnosis of this group was 10 days. A 30-degree pronated view, tomograms, and computed tomography scans may be necessary in the diagnosis of this injury. This fracture was found to be highly unstable. Ten patients underwent surgery for stabilization of their fractures and restoration of the congruity of the hamate-metacarpal joint. Four patients were treated with open reduction and internal fixation of the fracture. Six patients were treated with closed reduction and percutaneous pinning. All patients treated surgically had maintenance of reduction of their joints. One patient was treated with closed reduction and casting; reduction in this case was lost, and the patient developed residual subluxation of the hamate-metacarpal joint.

Use of titanium implants in pedicular screw fixation

Several types of pedicular screw systems have been utilized to augment lumbar spine fusion. All systems are made of stainless steel, which interferes with imaging techniques, especially MRI and CT scans. In search of a solution for this problem, we decided to study the use of titanium systems in the lumbar spine. Because there were no titanium pedicle screw systems available on the market, we decided to use the titanium Alta system currently used for femur fractures. This report details our experience in using this device for lumbar spine fusion. From 1990 to 1992, 25 patients underwent thoracic and lumbar fusion with Alta titanium screws and plates. Spinal fusion was performed for a variety of conditions, including metastatic tumor, fracture, spondylolisthesis, pseudoarthrosis, and postdecompressive instability. All but two patients obtained solid fusion clinically and radiographically and considerable improvement in back pain. There was loosening of the implant in both patients. Both patients had osteoporosis. One of these two patients developed pseudoarthrosis, which required further surgery. The other patient with a metastatic tumor of the spine remained asymptomatic without change in the spine alignment despite progression of the tumor. There were no broken screws encountered during follow-up. Two patients sustained subsequent fracture of the vertebra above the fusion. One of the patients also developed a fracture below the fusion. Fusion with titanium implants allowed postoperative evaluation and subsequent periodic examination of the spinal canal with high-quality MR images as well as significant reduction of artifacts on CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Computed Tomography-guided Intracranial Biopsy and Cyst Aspiration

A coordinated series of instruments has been developed for use in computed tomography (CT)-guided brain lesion biopsy and cyst aspiration: a plastic guide needle that is relatively free of CT artifacts, a ball-and-socket holding device for multidirectional sampling, and an aspiration-cutting biopsy needle that reliably produces consistent cores of tissue. Twenty-six biopsy and/or aspiration procedures have been performed on 24 patients with an overall biopsy success rate of 79%. The method is most reliable with highly malignant astrocytomas and least reliable with metastases and unusual primary tumors. There were 3 complications: 2 intratumoral hematomas and 1 death due to hemorrhage. A survey of published CT biopsy series shows an overall success rate of 85%. The rate of serious complications is 3.5% (including 3 deaths). The incidence of intratumoral hematomas that are clinically silent or associated with relatively minor clinical problems is 9%. CT-guided intracranial biopsy is more reliable than the earlier freehand methods and simpler than stereotactic techniques. It is the procedure of choice for percutaneous biopsy of superficial and deep hemispheric lesions.

Isolated rhombencephalosynapsis diagnosed by magnetic resonance imaging

A case of human rhombencephalosynapsis diagnosed in vivo by magnetic resonance imaging (MRI) is presented that demonstrates fusion of the dentate nuclei and agenesis of the cerebellar vermis. To our knowledge, this condition in its isolated form has been previously diagnosed only at necropsy. The developmental features of the cerebellum are discussed and correlation with cerebellar function is also presented. Recognition of this anomaly in the living patient may be useful in further understanding the clinical significance of segmentation of the rhombencephalon.

A Calcified Ligamentum Teres Mimicking Entrapped Intraarticular Bony Fragments in a Patient with Acetabular Fracture

A motor vehicle accident victim presented with a fractured acetabulum and had apparent entrapped bony intraarticular fragments seen on computed tomography scanning. At surgery, these fragments were found to be a partially avulsed calcified ligamentum teres that was apparently caused by a previous injury of the same hip. Excision of the calcified ligament and surgical stabilization of the acetabulum were performed. A calcified ligamentum teres may be confused with entrapped bony fragments and therefore cause difficulty in the evaluation and management of acetabular fractures.

Comminuted Fracture of the Calcaneus Associated with Subluxation of the Talus

Two cases of complex fracture dislocation of the calcaneus having an unusual pattern of injury are described. The cases exhibit the following special characteristics: (1) fracture dislocation of the calcaneus where the primary fracture line separates the calcaneus into an anteromedial fragment that maintains its normal relationship to the talus and a posterolateral fragment that is dislocated from the subtalar joint. This posterolateral fragment moves laterally and lies adjacent to the fibula; (2) a secondary fracture line separating the lateral portion of the posterior facet from the tuberosity of the calcaneus. Both fragments are dislocated from their normal anatomical position; (3) talar tilt as shown on AP view of the ankle caused by inversion of the talus due to rupture of the lateral collateral ligament. Also, the posterolateral fragments impinging on the fibula pushes the heel downward and contributes to the talar tilt; (4) involvement of the calcaneocuboid joint; (5) dislocation of the peroneal tendons. This fracture pattern is unusual and has not been described before. Recognition of this unusual injury with subsequent and proper management may prevent major disability to the patient. Conservative treatment by casting or early range of motion is contraindicated. Closed reduction should be attempted immediately, and if not successful, a lateral approach with open reduction and internal fixation is the treatment of choice for this complex injury.