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.

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).

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.

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.

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.

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.

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.

Cryoprobe-assisted removal of spinal cord tumors: technical note.

The application of a cryosurgical contact probe to assist in the removal of intraspinal neoplasms is described. Most often used by ophthalmic surgeons for intraocular extraction purposes, these .89-3 mm cryoprobes provide an ideal safe "handle" when attached to intramedullary or extramedullary spinal cord tumors and facilitate dissection and removal with standard microsurgical techniques.

A new solution for life without blood. Asanguineous low-flow perfusion of a whole-body perfusate during 3 hours of cardiac arrest and profound hypothermia.

BACKGROUND: The benefits of hypothermia for preventing ischemic injury are well known, but its application in surgery to protect the whole body during procedures requiring circulatory arrest is currently limited to < 1 hour at 15 degrees C using 50% hemodilution. In a significant departure from previous methods, we have developed a technique of asanguineous blood substitution with low-flow perfusion and cardiac arrest at < 10 degrees C in a canine model. Our approach has been to design a hypothermic blood substitute that would protect the brain and visceral organs during several hours of bloodless perfusion. Two different solutions have been designed to fulfill separate requirements in the procedure. METHODS AND RESULTS: With the use of extracorporeal cardiac bypass, 14 adult dogs were exsanguinated during cooling; 11 dogs were blood substituted using in combination the "purge" and "maintenance" solutions (group 1), and 3 dogs were perfused throughout with the "purge" solution alone as controls (group 2). After cardiac arrest, the solutions were continuously circulated for 3 1/2 hours by the extracorporeal pump (flow rate, 40 to 85 mL.kg-1.min-1; mean arterial blood pressure, 25 to 40 mm Hg). The temperature was maintained at < 10 degrees C (nadir, 6.6 +/- 0.1 degrees C) for 3 hours, and the hematocrit was kept at < 1% before controlled rewarming and autotransfusion. In the experimental group, the heart always started spontaneously in the temperature range of 11 degrees C to 27 degrees C, and 8 animals have survived long-term (current range, 14 to 110 weeks) without any detectable neurological deficit. In contrast, two control animals survived after extensive and aggressive cardiac resuscitation efforts; after surgery they exhibited transient motor and sensory deficits for approximately 1 week. Evaluation of biochemical and hematological parameters showed only a transient and inconsequential elevation in enzymes (eg, brain, liver, cardiac) in group 1 compared with the markedly greater elevations in group 2. For example, immediate postoperative values (mean +/- SEM) for lactate dehydrogenase were 114 +/- 10 for group 1 versus 490 +/- 210 for group 2 (P < .03); for SGOT, values were 93 +/- 18 for group 1 versus 734 +/- 540 for group 2 (P < .05). On day 1 for creatine kinase (CK), the group 1 value was 7841 +/- 2307 versus 71,550 +/- 2658 for group 2 (P = .03), and for CK-BB, the group 1 value was 108 +/- 22 versus 617 +/- 154 for group 2 (P = .03). Neurological evaluation using deficit scores (NDS) was based on a modification of the Glasgow Coma Scale score: 0, normal; 1, minimal abnormality; 2, weakness; 3, paralysis; 4, coma; and 5, death. At days 1 and 2 after surgery, NDS (mean +/- SEM) were 0 +/- 0 for the experimental group versus 1.5 +/- 0.5 for the control group. At days 3 and 7 after surgery, NDS were 0 +/- 0 for group 1 versus 1.0 +/- 1.0 for group 2. CONCLUSIONS: The faster neurological recovery of dogs treated with the "intracellular-type" maintenance solution supports the biochemical data showing the benefits of this type of blood substitute for extending the safe limits of hypothermic cardiac arrest procedures to > 3 hours.

Value of surgical intervention in the treatment of glioma.

The benefit of cytoreductive surgery in the management of glioma remains speculative. We therefore reviewed all confirmed deaths in our Neuro-Oncology Program and examined various clinical factors related to survival. There were 63 patients (34 males/29 females), with an average age of 57.6 years. The pathology was glioblastoma in 44 and anaplastic astrocytoma in 19; median survival was 12 months. Forty patients underwent at least one craniotomy, following which 22.5% achieved a gross total resection, 23 had biopsy only. Only age and gross total resection of tumor as judged by postoperative MR (CT in 2 cases) correlated significantly with outcome. The subtotal craniotomy group and biopsy only cohort were indistinguishable (median survival 11 vs. 10 months, respectively). Although craniotomy associated with gross total resection results in enhanced survival (median 27 months), subtotal tumor excision offers little beyond a diagnosis. Therefore, careful and realistic preoperative assessment of glioma patients ought to be performed to determine optimal surgical management.

Laser discectomy. Comparison of systems.

Percutaneous methods of lumbar disc removal have gained wide popularity since the introduction of the automated suction device. Newer methods to enter this field include the Nd:YAG and Ho:YAG lasers. To date, no experimental model exists to compare the efficacy of disc removal of these devices. An in vitro disc elastance (pressure/volume) model was designed that accurately reflects the mass of dry disc removed after any type of discectomy procedure. The experimental design consists of an infusion pump compressing a static column of air in line with the disc through a 12-gauge needle. Both mechanical and laser devices exhibited a reproducible treatment plateau, beyond which no disc removal was effected. Total energy, as opposed to power, was found to be the main determinant of the extent of disc removal during laser discectomy. Finally, in the experimental model of juvenile swine the automated suction device exhibited superior disc removal compared to the two lasers, but the clinical applicability of this is debatable. Disc space elastance offers a rapid and reproducible method to quantitate the extent of disc removal after intradiscal treatment methods and if employed in human cadaver spines may minimize the need for clinical trials to compare different devices and techniques.

Recurrent spheno-orbital meningioma.

A series of 15 patients who underwent neurosurgical procedures for recurrent spheno-orbital meningioma is reported. There were 11 women and four men, with a mean age of 46 years. The mean duration between the first and second operations was 46 months. Progressive proptosis without neurological deficit was the most common symptom. All tumors were large at the time of reoperation and involved the greater and lesser wings of the sphenoid bone and the orbit. Aggressive resection in all patients resulted in no deaths and only slight morbidity, with the exception of one patient who developed blindness 24 hours after surgery due to central retinal artery occlusion. Fourteen patients were improved cosmetically and one patient, treated early in the series, had persistent proptosis due to inadequate bone removal. No attempt was made to remove tumor within the cavernous sinus in patients who were neurologically normal. Although postoperative imaging demonstrated complete gross excision of tumor in nine patients, 10 underwent conventional radiation therapy for residual tumor visualized at the time of surgery in the dura of the superior orbital fissure, the cavernous sinus, or the basal optic canal. Although this study is inconclusive and requires further long-term documentation, no recurrences have been seen to date in the follow-up period, ranging from 16 to 95 months. The following important points are discussed: 1) the failure by experienced surgeons to radically excise bone, tumor, and involved dura at the first operation; 2) the importance of early aggressive therapy, depending upon the patient's age and medical condition; 3) the almost invariable intracranial dural involvement, which at times was seen only by gadolinium-enhanced magnetic resonance imaging and not visualized on computerized tomography; 4) an illustrated stepwise surgical technique for complete resection through a small craniotomy without the need for complicated reconstruction of the orbit or temporal fossa; 5) the role of radiation therapy when removal is incomplete or deemed hazardous because of cavernous sinus involvement; and 6) the excellent cosmetic results possible with minimal morbidity and no mortality.

Laser discectomy: a review.

The percutaneous treatment of lumbar disc disease with laser energy has emerged recently as an alternative to open surgical or even mechanical percutaneous methods. Although numerous laser wavelengths have been employed in both the experimental and clinical settings, no consensus exists regarding selection of laser, treatment duration, or energy requirements. Inspection of the disc/water absorption spectrum combined with the limitations of the fiberoptic delivery systems argue for the use of lasers near 2.0 microns, such as the 2.1-microns Ho:YAG. Although recently developed in vitro models have allowed for laser system comparisons, most clinical work has been empiric, uncontrolled, and in very small series.