Treatment of failed Adult Chiari Malformation decompression with CSF drainage: observations in six patients.

OBJECTIVE: We report the use of CSF drainage for the management of failed Adult Chiari Malformation (ACM) decompression. METHODS: All patients with more than one year follow-up after treatment of their failed ACM were included in this study. They underwent initial decompression between September 1998 and April 2000. Clinical and radiological data were collected initially and at recurrence. Lumbar punctures (LP) were done at recurrence for diagnostic and therapeutic purposes. Opening pressures and symptomatic relief were recorded. Therapeutic options included intermittent LP and ventriculo-peritoneal shunting (VPS). RESULTS: There were 6 patients (5 females and one male). Their age ranged from 19 to 43 years. Tonsillar descent ranged from 5 to 21 mm. The symptoms recurred 1.5 to 9 months postoperatively (average 5.6 months). Postoperative imaging revealed the presence of CSF flow behind the tonsils and the formation of a retrotonsillar neocistern in all patients. On LP, the opening pressure ranged from 17 to 31 cm of water (average 23 cm). All patients improved after CSF drainage, and four patients underwent VPS. The other patients were treated with repeat LP+/-Acetazolamide. There was significant improvement in all patients, with 18 months follow-up after CSF drainage (range 16-21 months). CONCLUSIONS: Our results suggest a role for CSF drainage in the treatment of some patients with failed ACM surgery. Possible explanations for the failure of ACM surgery in this subgroup include: surgical complications leading to neural hydrodynamic alteration, inadequate initial surgery, and coexistence with another pathology, possibly a mild form of intracranial hypertension. More prospective and hydrodynamic studies are needed to further clarify these issues.

A reappraisal of surgery for orbital tumors. Part I: extraorbital approaches.

Orbital lesions are variable in nature and location. Their management can be challenging, and surgical intervention is often needed. Although a significant percentage of these tumors are treated by the ophthalmologist alone, collaboration with a neurosurgeon is often required, especially for tumors that are located deep within the orbit, are large, or have an intracranial extension. Technical advances and modifications in surgical technique have decreased surgery-related morbidity and increased its success. The authors describe their rationale in the choice of a surgical approach, the surgical techniques for extraorbital approaches, and the new surgical adjuvants.

Surgery for orbital tumors. Part II: transorbital approaches.

Orbital tumors can be excised or biopsy samples obtained via transorbital approaches, especially those located in the anterior two thirds of the orbit. The indications and various surgical steps will be reviewed for the anterior, the anteromedial, and the lateral approaches. Some of these approaches can be combined or extended to accommodate large or deep-seated tumors.

Cerebral concussion in athletes: evaluation and neuropsychological testing.

OBJECTIVE: To conduct a topic review of studies related to cerebral concussion in athletes, as an aid to improving decision-making and outcomes. METHODS: We review the literature to provide an historical perspective on the incidence and definition of and the management guidelines for mild traumatic brain injury in sports. In addition, metabolic changes resulting from cerebral concussion and the second-impact syndrome are reviewed, to provide additional principles for decision-making. Neuropsychological testing, as it applies to athletes, is discussed in detail, to delineate baseline assessments, the characteristics of the neuropsychological evaluation, the neuropsychological tests used, and the methods for in-season identification of cerebral concussion. Future directions in the management of concussions are presented. RESULTS: The incidence of cerebral concussions has been reduced from approximately 19 per 100 participants in football per season to approximately 4 per 100, i.e., 40,000 to 50,000 concussions per year in football alone. The most commonly used definitions of concussion are those proposed by Cantu and the American Academy of Neurology. Each has associated management guidelines. Concussion or loss of consciousness occurs when the extracellular potassium concentration increases beyond the upper normal limit of approximately 4 to 5 mmol/L, to levels of 20 to 50 mmol/L, inhibiting the action potential and leading to loss of consciousness. This phenomenon helps to explain the delayed effects of symptoms after trauma. CONCLUSION: Neuropsychological testing seems to be an effective way to obtain useful data on the short-term and long-term effects of mild traumatic brain injury. Moreover, knowledge of the various definitions and management strategies, as well as the utility of neuropsychological testing, is essential for those involved in decision-making with athletes with mild traumatic brain injuries.

Does loss of consciousness predict neuropsychological decrements after concussion?

OBJECTIVE: To investigate the importance of loss of consciousness (LOC) in predicting neuropsychological test performance in a large sample of patients with head injury. DESIGN: Retrospective comparison of neuropsychological test results for patients who suffered traumatic LOC, no LOC, or uncertain LOC. SETTING: Allegheny General Hospital, Pittsburgh, Pennsylvania. PATIENTS: The total number of patients included in this study was 383. MAIN OUTCOME MEASURES: Neuropsychological test measures, including the visual reproduction, digit span, and logical memory subtests of the Wechsler memory scale (revised), the Trail Making test, Wisconsin Card Sorting test, Hopkins Verbal Learning test, Controlled Oral Word Association, and the Galveston Orientation and Amnesia test (GOAT). RESULTS: No significant differences were found between the LOC, no LOC, or uncertain LOC groups for any of the neuropsychological measures used. Patients who had experienced traumatic LOC did not perform more poorly on neuropsychological testing than those with no LOC or uncertain LOC. All three groups demonstrated mildly decreased performance on formal tests of speed of information processing, attentional process, and memory. CONCLUSION: The results of this study cast doubt on the importance of LOC as a predictor of neuropsychological test performance during the acute phase of recovery from mild traumatic brain injury. Neuropsychological testing procedures have been shown to be sensitive in measuring cognitive sequelae of mild traumatic brain injury (concussion) in athletes. The failure of this study to find any relationship between LOC and neuropsychological functioning in a large sample of patients with mild head trauma calls into question the assignment of primary importance to LOC in grading severity of concussion. This study also does not provide support for the use of guidelines that rely heavily on LOC in making return-to-play decisions. Continued research is necessary to determine the relative importance of markers of concussion in athletes.

Association between peridural scar and persistent low back pain after lumbar discectomy.

The purpose of this study was to investigate the correlation between low back pain persisting six months after first surgery for herniated lumbar intervertebral disc and the extent of peridural fibrosis present at the surgical site, as defined by magnetic resonance imaging (MRI). The 298 patients who underwent first-time, single-level unilateral discectomy for lumbar disc herniation were evaluated in a controlled, randomized, double-blind multicenter clinical trial to test the effectiveness of the scar-inhibiting device ADCON-L. Clinical assessments were conducted pre-operatively and at 1, 3, and 6-month intervals post-operatively, and included MRI scar assessment and the assessment of low back pain by visual analog scales. There were 267 patients available for low back pain assessments. The data obtained at the 6-month follow-up visit were statistically analyzed for the association between the presence of peridural scar and the persistence of low back pain. Those patients treated with ADCON-L at surgery had significantly less scar than did control patients (p = 0.007), and had less low back pain than did control patients when the pain was most severe (p = 0.047) and when the pain was assessed at the end of the day (p = 0.044). Patients with extensive scar reported continuing and debilitating low back pain more frequently than those with no or minimal scar. These findings demonstrate a direct correlation between persistent low back pain and extensive scar, since patients with increased amounts of scar had increased low back pain, regardless of their treatment group (p = 0.0003).

Repair of carotid artery perforations during transsphenoidal surgery.

BACKGROUND: Hemorrhage from carotid artery injury during transsphenoidal surgery is an unusual, but potentially fatal complication. METHODS: Among six patients experiencing laceration or perforation of the carotid artery, we treated four with a new technique using Teflon mesh and methyl methacrylate to form an external, artificial wall over the laceration and the carotid artery. RESULTS: In all four cases, hemorrhage was successfully controlled without neurologic deficit to the patient or complications frequently associated with the standard technique of nasal and sphenoid sinus packing removal. CONCLUSIONS: Our new technique may be superior to packing alone, as well as potentially life-saving to the patient.

The posterior inferior orbitotomy.

Four patients with orbital apex tumors between the optic nerve and inferior rectus underwent a posterior inferior orbitotomy through the maxillary sinus. Three tumors were removed successfully and the fourth was not located, but the visual function improved after surgery, presumably owing to decompression of the posterior orbital floor. The technique was carried out through a standard Caldwell-Luc approach through the maxillary sinus. The posterior inferior orbital wall was removed and the inferior rectus was retracted either laterally or medially to gain access to the tumor, which was removed microsurgically. The authors believe this approach provides a reasonably safe alternative to remove small, well-circumscribed, inferior posterior orbital apical tumors. It also avoids dissection through the orbit from other directions with the inherent risks of damaging overlying vital structures.

Intraosseous meningioma.

A 71-year-old woman with a long history of slowly progressive proptosis was found to have an intraosseous meningioma of the right sphenoid bone. Radiologically, the lesion resembled fibrous dysplasia. The key to the diagnosis is irregularity of the inner table of the skull. The histologic appearance is characteristic. Intraosseous meningioma is one part of the spectrum of diseases known as primary extraneuraxial meningioma. In this paper we discuss the theories of cellular origin as well as the radiologic differential diagnosis.

Outcome after microdiscectomy: results of a prospective single institutional study.

BACKGROUND: Although lumbar microdiscectomy is one of the most frequently performed spinal procedures, little consensus exists in the literature regarding results. Whereas retrospective reports boast success rates as high as 98%, prospective studies are less sanguine with statistics in the 73-77% range. METHODS: Prospective single-institution outcome study of all patients undergoing virgin unilateral single-level microdiscectomies by study surgeons November 1990 to March 1992. Outcome determined by patient-reported responses to mail questionnaire or phone interview by a disinterested party. RESULTS: There were 374 patients operated on, average age 42.4 years with mean length of symptoms 9.4 months, and 31.5% were Workman's Compensation cases. Total complication rate was less than 4%, and follow-up was accomplished for 86% of the patients. Overall success rate was 74% using a strict combination of patient-reported pain relief, work status not affected, absence of narcotic use, and satisfaction with the procedure. Using a multivariate logistic regression analysis, only Workman's Compensation claim and length of symptoms (>6 months) were related to success, with a positive outcome in 86% of non-Compensation patients with brief symptoms contrasting with 29% in Compensation cases of greater than 6 months duration. CONCLUSIONS: A prospective analysis of the frequency of success after microdiscectomy yields results lower than anticipated based on retrospective studies and finds success related to the non-anatomic factors of length of symptoms and Workman's Compensation claims.

Computer navigational microscope for minimally invasive neurosurgery.

Frameless navigational devices have recently undergone an evoluation to the point where they are being used more efficiently in the clinical setting. Most of the present-day systems utilize some form of mechanical arm to correlate registered points in space to the computer terminal. However, the articulated arm can be cumbersome and is an additional obstacle in the surgical field. To avoid this problem some groups have elected to transmit registered points and probe position using ultrasound or electromagnetic fields. However, in using magnetic fields, ferromagnetic metals can interfere with accuracy. On the other hand with ultrasonic digitizers accuracy is dependent on variable factors such as humidity, local temperature, and positioning of the emitters. In response to some of these difficulties inherent with frameless stereotaxy, the MKM system was developed. Essentially it is an optically based system in which the CT and/or MRI data are superimposed three-dimensionally onto the surgical field as seen through the microscope using head-up display technology. It requires no opto-kinetic link such as a headframe, mechanical arm, ultrasonic, and magnetic field. We have used the MKM microscope system to guide 18 neurosurgical procedures. This report illustrates the advantages of this system when combined with keyhole surgery to provide accurate excision of brain lesions while preserving normal tissue.

Utilization and cost savings of a wide-area computer network for neurosurgical consultation.

BACKGROUND AND OBJECTIVE: Telemedicine systems offer many potential advantages for health care delivery. Most reports have centered on the delivery of primary and medical subspecialty care rather than on its impact on patient care and the potential for cost savings. In 1993, we implemented NeuroLink, a wide-area teleradiology network for delivery of specialty care in neurologic surgery at Allegheny General Hospital (AGH). This study was designed to determine the potential cost savings of such a network. METHODS: We prospectively reviewed 100 consecutive telemedicine neurosurgical consultations from 20 western Pennsylvania community hospitals participating in the NeuroLink network. Data related to referring hospital, diagnosis, disposition of the patient, and mode of transportation were reviewed. To determine the potential cost savings, the differential of hospital-based charges between AGH and western Pennsylvania primary hospitals was calculated based on an average length of stay (LOS), patient bed costs, and transportation charges. RESULTS: Of the 100 patients, 33 did not require transfer to a tertiary facility but were instead managed at the community hospital as a direct result of the remote diagnosis and image review disclosing that neurosurgical procedures or intensive care were not required. Cost analysis, comparing the average LOS at AGH with that of the average community hospital, including transportation, showed savings of $502,638. CONCLUSION: Our neurosurgical wide-area computer network has led to more appropriate transfer of patients to a tertiary facility and significant estimated cost savings.

Detection of membrane-associated human chorionic gonadotropin and its subunits on human cultured cancer cells of the nervous system.

Cultured human cancer cells from the nervous system, which included brain cancers, neuroblastomas, medulloblastomas, and retinoblastomas, were analyzed by analytical flow cytometry for the presence of membrane-associated human chorionic gonadotropin (hCG), its subunits, and fragments. Live cells and a panel of monoclonal antibodies directed to epitopes located in three different sites of the hCG molecule were used in the analysis. For in vivo studies, the cultured human glioma cells were grown in athymic (nude) mice, and their tumors were excised and fixed in Bouin's fixative, and embedded in paraffin for subsequent immunocytochemical analysis of tissue sections. Cells from a benign uterine leiomyoma were used as a negative control. Membrane-associated and cytoplasmic hCG, its subunits, and its fragments were present in cells from all the cancers studied. These results correlate with our in vitro and in vivo studies which showed the presence of translatable levels of hCG beta mRNA in all cancers, including the cancers of the nervous system, proving that these malignant neoplasms are no different from carcinomas, sarcomas, malignant lymphomas, or leukemias in that they all have the same biochemical denominator. Our findings give the scientific basis for the use of active and/or passive immunization against hCG for prevention or as a primary adjuvant therapy for these types of cancers.

Defining the limits of survivorship after very severe head injury.

BACKGROUND: Reliable prediction of outcome after head injury is a daunting task. Although previous reports have highlighted the difficulties of determining outcome in the cohort of severe head injury Glasgow Coma Scale (GCS) score < or = 8), we wondered within the very severely injured population (GCS score 3-5) if a simple combination of clinical parameters may be predictive of poor outcome. METHODS: All patients admitted to a Level 1 trauma center with a GCS score of 3 to 5 from 1986 to 1991 inclusive (380 patients) were retrospectively reviewed and outcome a minimum of 6 months after injury was determined by chart review or telephone. RESULTS: Follow-up was accomplished in all but five patients (1.3%). Functional survival (nonvegetative) was correlated to admission GCS score, pupillary abnormalities, and age. As anticipated, overall functional survival was poor (12.5%), and even worse among those evidencing pupillary abnormalities (6.6%). Interestingly, there was an absence of survivors in the advanced age decades, with the oldest functional survivor of any GCS increasing in a stepwise fashion with increasing coma score. This translated into the oldest survivor of a GCS score of 3 being in their chronologic 30s, a score of 4 in their 40s, and a score of 5 in their 50s. Among patients older than these age decades, that is beyond this simple age/GCS cut-off (32.8% of cohort), there were no functional survivors (95% confidence interval 0, 2.4). CONCLUSIONS: Within the population of very severely head injured patients (GCS score 3-5), the simple combination of age and admission GCS score appears to predict accurately non-functional outcome in almost one third of patients. If confirmed at other centers, this may have wide-ranging implications regarding counseling of families, utilization of resources, and the design of head injury studies.

The role of postoperative irradiation in the management of sphenoid wing meningiomas. A preliminary report.

PURPOSE: To determine whether postoperative radiation therapy decreases recurrence rates in subtotally excised and recurrent sphenoid wing meningiomas. METHODS: Patients with primary subtotally excised and recurrent sphenoid wing meningiomas who underwent surgery between 1981 and 1994 (n = 105) were prospectively followed for recurrence. Postoperative radiation was not recommended in patients who had complete excision; therefore, their recurrence rates were not evaluated in this study. Patients with malignant meningiomas also were excluded from analysis. Recurrence was defined as evidence of tumor growth on neuroimaging with or without clinical symptoms. RESULTS: Follow-up information was available for 86 patients; 69 had primary subtotally excised tumors and 17 had recurrent tumors. Follow-up information was unavailable in the remaining 19 patients. Tumor location and histopathology, type of surgery performed, and patient sex and age were similar in the irradiated and nonirradiated subgroups. Postoperative irradiation was delivered to 31 patients with primary tumors and 11 with recurrent tumors; none of these 42 patients had recurrence during a mean observation period of 4.2 and 3.5 years, respectively. The nonirradiated group consisted of 38 patients with primary tumors and 6 with recurrent tumors; 16 of 18 patients who had primary meningiomas had a recurrence and 5 of 6 who had recurrent tumors had another relapse (mean interval between resection and recurrence, 4.4 years and 14 months, respectively). CONCLUSIONS: Postoperative radiation appeared to delay recurrence in subtotally excised and recurrent sphenoid wing meningiomas during the time frame of this study.

The learning curve for acoustic tumor surgery.

Although operative experience is considered to be critically important in the surgical management of acoustic tumors, little objective evidence substantiates this claim. The present study was undertaken to determine whether a learning curve exists for acoustic tumor surgery. The first 96 acoustic tumor patients managed surgically by a new neurotologic team were retrospectively reviewed. A significant improvement (P<.0003; F=6.32) in the ability to achieve good (grade II or better) postoperative facial nerve function was identified. Improving trends for complete resection rate and hearing preservation were documented, and the incidence of cerebrospinal fluid (CSF) leaks declined; however, statistical significance was not achieved. For postoperative facial nerve function, approximately 60 cases were necessary before the new team achieved results similar to those of highly experienced surgeons. The frequencies of complete resection, CSF leaks, hearing preservation, stroke, and mortality were comparable to those of experienced neurotologic teams. The findings of this study may have implications for both patient care and physician training.

Athletes with cervical spine injury.

Athletic injuries to the cervical spine are infrequent, but can present difficulty in both diagnosis and management. We designed a simple classification system consisting of three broad types of injuries to facilitate management decisions. Also included is a discussion of variations among injuries within each type and recommendations regarding the athlete's return to competition.

Automated percutaneous discectomy.

Automated percutaneous discectomy is the most popular technique for intradiscal therapy of lumbar disc disease, with over 80,000 procedures performed worldwide to date. Success rates range from 55% to 85%, and complications are very infrequent (less than one percent). Very careful patient selection seems critical for success.