Injuries of the central base of the skull

In different types of lesions, especially in frontobasal and laterobasal ones, the central base of the skull is injured, too (in about 20% of severe frontabasal lesions). Surgical treatment is necessary. Examination of intra- and infrabasal structures and localized intracranial operations may be performed by transthemoidal-transphenoidal or transpyramidal approaches. Main problems are the treatment of dura lesions, the control of hemorrhages, the examination of the optic nerve, and the compensation of disturbances of central regulation. The above experiences we gathered from patients in the ORL Clinic of Jena University.     

The system of the modified transcochlear approach: a lateral avenue to the central skull base

OBJECTIVE: This study aimed to update the authors' experience with the modified transcochlear approach for the management of lesions of the central skull base. The surgical technique, classification, indications, and results also are presented. STUDY DESIGN: A retrospective review of the charts of 66 consecutive patients treated in our centers by the modified transcochlear approach was conducted. SETTING: The study was performed in two tertiary referral centers. PATIENTS: All patients treated by the modified transcochlear approach were included. Thirty-five patients had extradural lesions, whereas 31 lesions were intradural. INTERVENTION: All patients were treated surgically using the modified transcochlear approach either in its basic form (type A) or with its extensions (types B, C, and D). MAIN OUTCOME MEASURES: The outcome of surgery is evaluated with particular emphasis on the incidence of morbidity, mortality, and the degree of total tumor removal. RESULTS: Total tumor removal was accomplished in 58 cases either in single or staged procedures. A second-stage procedure for total tumor removal is planned in five other patients. Subtotal tumor removal was performed in three patients. Mortality occurred in two cases. Ipsilateral hearing loss and immediate facial nerve palsy constituted the major drawbacks of this approach. However, 67.5% recovered to grade III facial function or better 1 year after surgery. CONCLUSIONS: The modified transcochlear approach provides a relatively safe, wide, and versatile access to large lesions of the central skull base.     

Chordomas of the skull base: dynamic MRI

OBJECTIVE: To investigate the role of dynamic MRI in the diagnosis of chordomas at the skull base. MATERIALS AND METHODS: Six patients with surgically proven chordomas of the skull base were examined with spin-echo technique (repetition time/echo time 200 ms/15 ms). Serial imaging was performed every 30 s for 240 s after a rapid injection of gadopenetate dimeglumine (0.1 mmol/kg). The contrast material enhancement ratio (CER) was analyzed. The CER was obtained for each region of interest as follows (Sn - So) x 100/Smax - So, where Sn indicates signal intensity at each dynamic phase; So, signal intensity on the image obtained before administration of contrast material; and Smax, maximum signal intensity of all dynamic imaging. RESULTS: All chordomas showed very slow but steady increase of contrast enhancement with no peak within 240 s. The CERs of six cases at 30 s are 13 to 40 (mean value +/- standard deviation: 22.8 +/- 10.2). CONCLUSION: Dynamic MRI may be helpful in differentiating between chordomas and other tumors of the skull base.     

Atypical central nervous system lymphoma at the cranial base: report of four cases

OBJECTIVE AND IMPORTANCE: Primary central nervous system lymphoma is a disease with increasing incidence. Atypical presentations are becoming more frequent. CLINICAL PRESENTATION: Three patients bearing cavernous sinus lesions presented initially with periorbital pain and diplopia. Tolosa-Hunt syndrome was the initial presumptive diagnosis for two patients, and meningioma was the diagnosis for the third patient. A fourth patient presented with left ear pain, and a mass in the left internal auditory canal was thought to represent an acoustic neuroma. INTERVENTION: For all four patients, an operative pathological diagnosis was obtained and was compatible with central nervous system lymphoma. All patients were treated with osmotic blood-brain barrier disruption with intra-arterial chemotherapy using a methotrexate-based regimen. CONCLUSION: All four cases included atypical presentations of lymphoma. These cases again illustrate that a correct diagnosis cannot be obtained based only on imaging and clinical findings.     

Surgery of the anterior skull base

Inflammatory disease of the frontal, ethmoid, and sphenoid paranasal sinuses may extend to the adjacent anterior skull base and then intracranially. The potential for this serious complication of sinus disease must be recognized by the primary otolaryngologist-head and neck surgeon, and alternative management strategies must be taken once it is diagnosed. Topics discussed in this article include cranial anatomy, surgical techniques and variations, complications, and special considerations.     

Surgery of the base of the skull

To treat pathological processes, primarily tumors, in the base of the skull is one of the most intricate neurosurgical problems. In the past decade, interest in this problem has greatly increased due to the advent of new methods of diagnosis, up-to-date neurosurgical equipment and to a greater cooperation of physicians of related disciplines: ophthalmologists, otosurgeons, plastic surgeons. The authors present and summarize the experience accumulated by the researchers of the N. N. Burdenko Institute of Neurosurgery in the past 10 years in treating basal tumors. Based on a great deal of clinical findings, approaches are proposed in treating some groups of basal tumors, such and pituitary adenomas, craniopharyngiomas, meningiomas at various sites, trigeminal and acoustic neurinomas, and malignant neoplasms of the base of the skull. The conditions required for successful surgical treatment of the processes in the base of the skull are described in detail. One of them is a correct determination of a surgical approach.     

Non-Hodgkin lymphoma of brain occurring after cardiac transplantation

This case report concerns a case of NHL which affected a 56 year-old patient after cardiac transplantation. The patient was hospitalized because of worsening congestive failure. Despite maximal medical treatment the patient continued to be in NYHA Class III-IV and underwent orthotopic cardiac allograft transplantation. The NHL developed in the CNS eighteen months after surgery and had a very quick lethal progression.     

Congenital encephalocele of the medial skull base

Intensive case management for severely psychiatrically ill patients is a relatively new phenomenon in the private sector. The authors describe a comprehensive case management program designed at Blue Cross Blue Shield of Massachusetts to meet the needs of the most severely ill psychiatric patients in a private managed care environment. The case management program emphasizes involvement of patients in creating comprehensive treatment plans; development of a relationship between case managers, patients and their families, and providers; and clinical coordination between the public and private sectors to create individualized treatment plans. The program's case managers are able to flex the benefit limitations of a managed care or indemnity plan to integrate public and private services and can enlist providers outside a managed care network. The paper describes service utilization by the first 33 patients who participated in the program for one year.     

Treatment of posterior skull base tumors

Treatment of ureteral stenosis has been attempted in many patients with transplanted kidneys. Treatment with the Acucise catheter system is a new approach for such patients. Published results of the approach in eight patients promise safety, effectiveness, and low perioperative morbidity. We report two cases of transplant ureteral stenosis treated with Acucise. One patient with stenosis of the pyeloureteral junction was treated successfully and has been free of recurrence for 9 months. The other patient had long-distance stenosis of the lower portion of the transplant ureter. Acucise incision was successful, but the patient had to undergo uretero-neocystostomy because of a ureteroperitoneal fistula. We use these cases to illustrate the disadvantages of endourological ureteral surgery as a standard therapeutic approach after renal transplantation. We suggest that Acucise is reliable when used in patients with uncomplicated short-distance ureteral stenosis; however, patients with long-distance stenosis or stenosis caused by heavily scarred periureteral tissue will not profit from it because of a higher complication rate.     

Use of preoperative MR to predict dural, perineural, and venous sinus invasion of skull base tumors

PURPOSE: To assess the accuracy of MR imaging in predicting dural, venous sinus, and perineural invasion by skull base tumors. METHODS: The preoperative MR images of 22 patients who had resection of skull base neoplasms were evaluated for the following characteristics: dural enhancement, pial enhancement, local perineural invasion by adjacent tumor, and venous sinus invasion by tumor. The greatest width of dural enhancement was measured, and the character of dural enhancement was noted. The pathologic and surgical reports were reviewed retrospectively with specific attention to dural, venous, and local perineural invasion. RESULTS: Of the 22 patients studied, dural invasion by tumor was confirmed in eight patients, vascular invasion in six patients, and perineural invasion in four patients. The sensitivity of dural enhancement in predicting invasion was 88%, the specificity 50%, and the accuracy 64%. When enhancement and focal nodularity were present, the sensitivity remained at 88%; however, specificity was 100% and accuracy 95%. If the dural enhancement was more than 5 mm thick, sensitivity, specificity, and accuracy were 75%, 100%, and 91%, respectively. Predicting tumor invasion of the dura by the presence of pial enhancement was 50% sensitive and 100% specific. Venous sinus/jugular vein invasion was predicted with 100% sensitivity, 94% specificity, and 95% accuracy. Local perineural invasion was predicted with 100% sensitivity, 50% specificity, and 59% accuracy. CONCLUSIONS: The presence of pial enhancement, focal dural nodules, or dural thickening of more than 5 mm is highly accurate in predicting the presence of neoplastic dural invasion. Linear enhancement of dura does not imply dural infiltration by tumor. Venous invasion by tumor can be predicted accurately with preoperative MR imaging.     

Microsurgical treatment of midfacial tumours involving the skull base

PROBLEM: In rats, immunization with male accessory gland (MAG) extract promotes experimental autoimmune vesicle prostatitis. A specific mononuclear cell-mediated immune response and prostate androgen metabolism impairment in MAG-immunized rats were observed. The possibility that lymphocytic soluble factors (SoFs) can regulate the local steroid metabolism in these rats directly was studied. We investigated whether the SoFs released by MAG-sensitized lymphocytes are capable of modifying the prostatic androgen metabolism and whether they induce histologic lesions "in vivo" when they are inoculated, carried by liposomes, into untreated rats. METHOD OF STUDY: "In vitro" enzymatic [3H]-5 alpha-dihydrotestosterone bioconversion and histologic studies were performed with prostates from SoF-treated rats (LK rats). The obtained 3 alpha/beta-hydroxysteroid-oxidoreductase activities showed that LK rat values were significantly lower than in controls: 79.0 +/- 2.5 vs 158.7 +/- 10.2 pmol/min/mg protein, respectively (P < 0.01). RESULTS: In the histologic studies, LK rat prostates showed focalized mononuclear infiltrates of various degrees, whereas control rats showed non-atypic modification of the gland. CONCLUSION: These results indicate that SoFs (probably total lymphokines) contribute significantly to the pathogenesis of experimental autoimmune prostatitis, involving a biochemical relationship between immune reaction and the androgenic enzymatic inhibition in the prostate.     

MR findings of primary central nervous system lymphoma in a child. A case report

Huntington's disease is an autosomal dominant, inherited disorder that results in progressive degeneration of the basal ganglia (especially the neostriatal caudate nucleus and putamen) and other forebrain structures and is associated with a clinical profile of movement, cognitive and psychiatric impairments for which there is at present no effective therapy. Neuropathological, neurochemical and behavioral features of the disease can all be reproduced in experimental animals by local injection of excitotoxic or metabolic toxins into the neostriatum. All these features of the disease can be alleviated, at least in rats, by transplantation of embryonic striatal tissue into the degenerated striatum, which was the basis for commencing the first clinical trials of striatal transplantation in Huntington's patients. However, although rat striatal xenografts may temporarily reduce apomorphine-induced dyskinesias in monkeys, there has been no demonstration that allograft techniques that work well in rats translate effectively to the much larger differentiated striatum of primates. Here we demonstrate good survival, differentiation and integration of striatal allografts in the primate neostriatum, and recovery in a test of skilled motor performance. Long-term graft survival in primates indicates probable success for clinical transplants in Huntington's disease; in addition, our data suggest that graft placement has a direct influence on the pattern and extent of functional recovery.     

Chordomas of the skull base. Radiologic and clinical evaluation

Chordomas are uncommon skull base tumors, which are locally agressive and are usually not amenable to complete surgical resection. Proton beam irradiation, following surgery, is the preferred treatment modality. For diagnosis and determination of tumor site and extension, CT and MR imaging are the imaging modalities of choice. CT delineates bone destruction and the presence of calcifications and destroyed bone optimally. MR imaging is the modality of choice for better definition of the tumor margin from brain and other soft tissue structures (pharynx) and visualization of blood vessels. The signal intensities and enhancement pattern fail to differentiate chordoma from chondroid chordoma or chondrosarcoma. Chordomas arise from the clivus and therefore are located more centrally, whereas the majority of chondrosarcomas originate in the petroclival fissure and occur more laterally, although occasional overlap occurs in about one third of cases. Immunohistochemical methods allow differentiation of pure chordoma from chondroid chordoma and chondrosarcoma. Chordomas have a lower local control rate than chondrosarcomas.     

Solitary giant skull base schwannomas--report of four cases

BACKGROUND: Solitary intracranial schwannomas not related to major nerves or neurofibromatosis as well as paranasal schwannomas are rare. Schwannomas simultaneously involving the paranasal sinuses and intracranial cavity are even rarer. METHODS: We report four cases of schwannomas simultaneously involving the intracranial cavity and paranasal sinuses. They were successfully managed by surgery. The literature on such tumors is reviewed. RESULTS: All patients were young adults; the male to female ratio was 1:3. In two patients, the tumor was predominantly intracranial with extension into the sphenoid and ethmoid sinuses, whereas in the other patients, the tumor was located predominantly in the paranasal sinuses and nasopharynx with intracranial extension. Radiologically, bone destruction was seen in three cases. The tumors were totally removed piecemeal with repair of the basal dura. Histopathologic examination confirmed the diagnosis of schwannoma in all four cases. Three patients are alive and well; one of them was reoperated for a recurrence. CONCLUSIONS: These tumors should be excised completely if possible. Radiologically, bone erosion or destruction are suggestive of malignancy but histopathology clinches the diagnosis. Therefore, drastic surgery should be avoided in these cases. Surgery is generally curative in these massive schwannomas.     

The facial approach to the median structures of the skull base

Numerous routes of access to the medial basal structures of the cranium have been described, largely because of the wide variety of lesions observed in deep localizations. Access can be achieve via trans-sinusal, transfacial (trans-sphenoidal rhinoseptal, mediofacial or Lefort I), trans-oro-pharyngeal and numerous other routes. An examination of the principals involved, their development and the technical modalities demonstrate the advantages and disadvantages of each and their specific indications. Access is particularly interesting with the frontal trans-sphenoid, Lefort I osteotomy and trans-oro-pharyngeal routes. The simplicity of these non-mutilating routes provide an alternative to neurosurgical access. Their development depends on progress in imaging and microscopic surgery. Used alone or in combination, they can be an useful complement to a neurosurgical access.     

Non-Hodgkin lymphoma as a cause of intrahepatic periportal low attenuation on CT

Two cases of non-Hodgkin lymphoma (NHL), one AIDS related, with hepatic involvement manifesting as infiltrating mass-like periportal intrahepatic low attenuation on CT are described. One case demonstrated mass effect with compression of adjacent bile ducts causing jaundice. NHL should be included in the differential diagnosis of mass-like periportal intrahepatic low attenuation lesions.