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.

Intraoperative microvascular Doppler sonography in aneurysm surgery.

OBJECTIVE: The goal was to evaluate the efficacy and reliability of intraoperative microvascular doppler sonography for the assessment of cerebral hemodynamics in aneurysm surgery. METHODS: For 35 patients who underwent surgery for the treatment of 42 intracranial aneurysms, microvascular doppler sonography with a 20-MHz probe (1-mm diameter) was used before and after clip application, to confirm the obliteration of aneurysms. Assessment of the patency of the parent vessels and all branching arteries was performed. The findings from doppler sonography were confirmed with either intraoperative angiography or immediate postoperative angiography. RESULTS: The 1-mm microprobe was able to insonate all vessels of the circle of Willis and their major branches; furthermore, perforating arteries were reliably insonated. For 11 patients (31%), doppler sonography exposed parent artery or branching artery stenosis or occlusion and guided the immediate adjustment of aneurysm clip placement. The findings from intraoperative microvascular doppler sonography correlated with findings from angiography in all cases. There were no complications of microvascular doppler probe use. CONCLUSION: Intraoperative microvascular doppler sonography is a safe, instantaneous, effective, reliable, and cost-effective method for documenting the patency of parent vessels, arterial branches, and major perforators and the complete occlusion of cerebral aneurysms. This technique can be reliably used, in many instances, instead of intraoperative angiography for the surgical treatment of aneurysms.

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.

Neurolink: a neurosurgical wide-area computer network.

A computerized system capable of transmitting digitally formatted images of the central nervous system has been used to develop a neurosurgical wide-area network in western Pennsylvania. This system links remote or primary care hospitals with a large, tertiary-care, Level 1 trauma center for the constant availability of neurosurgical evaluation by receiving and interpreting computed tomography and magnetic resonance images sent via ordinary public telephone lines. This network has been used in over 20 cases to receive and interpret transmitted cranial computed tomographic images consisting of subarachnoid hemorrhage, intracerebral hematoma, cerebral neoplasm, cerebral abscess, cerebrovascular accident, and normal studies. There has been no known instance of false-positive or false-negative interpretation or of a patient being adversely managed by this method. On the contrary, it appears that patient management has been positively affected through the ability of the neurosurgical evaluation to include a review of the radiological studies. The initial experience has led to the conclusion that this network is an effective, accurate, and cost-effective means of delivering neurosurgical care to underserved areas.

Cryosurgery re-visited for the removal and destruction of brain, spinal and orbital tumours.

Advances in neuroimaging and cryosurgical techniques have prompted us to re-evaluate the potential of cryosurgical techniques for the removal and the destruction of various neoplasms. We have used cryosurgical instrumentation to remove tumours in the brain, spine and orbit in 71 patients without complications. Cryosurgery was used to facilitate removal and extraction in 64 and to destroy residual neoplasms when removal was incomplete in 7. Intraoperative real time ultrasonic imaging permitted precise delimitation of tumours from surrounding tissues and allowed monitoring during the production of cryosurgical lesions thus permitting heretofore unavailable visualization of the production of cryogenic lesions in the central nervous system. New cryosurgical instrumentation was used to produce lesions up to three times larger than similar sized probes previously available. Our results reconfirm that cryosurgery facilitates the removal of tumours in the brain, spinal cord and orbit, reduces blood loss in vascular tumours, and is effective in ablating residual neoplasms involving the superior sagittal sinus, torcula and parasagittal areas. A Doppler flowmeter proved useful for monitoring sagittal sinus blood flow during the production of cryosurgical ablation of residual tumour attached to the walls of the sagittal sinus. Recent advances in ultrasonic and neuroimaging coupled with stereotactic techniques and improvements in cryosurgical instrumentation may prove useful in the future percutaneous destruction of selective intracranial neoplasms.

Intraoperative angiography and temporary balloon occlusion of the basilar artery as an adjunct to surgical clipping: technical note.

The direct surgical treatment of intracranial aneurysms is not always possible, especially in posterior circulation aneurysms. This is usually because of their complex anatomy and location next to the skull base and brain stem, where proximal vascular control is usually not attainable. Four patients at our institution underwent intraoperative transfemoral catheterization of the basilar artery with a nondetectable endovascular balloon for proximal control of the basilar artery. The flow control in the basilar artery was excellent and facilitated the surgery. Before surgery, each patient underwent the placement of a 10-cm 8-French femoral introducer sheath and were taken to the operating room where they were placed in a supine position and a subtemporal or pterional craniotomy was performed. After the initial exposure and before aneurysm manipulation, a nondetachable silicone balloon catheter was passed through an introducer catheter and was placed into the rostral basilar artery, using flow direction, microguidewires, and angiographic "road-mapping" techniques. In two patients, temporary basilar occlusion was used to collapse the aneurysm and to facilitate clip placement. In the third patient, intraoperative aneurysm rupture occurred and was controlled by temporary basilar artery occlusion. Using intraoperative angiography, complete aneurysm obliteration and vessel patency was confirmed in all four patients. All patients made a complete recovery except for initial postoperative third nerve palsies in three patients. This technique achieves intraoperative control of the basilar artery proximal to an aneurysm by the use of a nondetachable occlusive balloon in the basilar artery. An added benefit is the ease with which intraoperative angiography can be obtained in this context.(ABSTRACT TRUNCATED AT 250 WORDS)

Thromboendarterectomy of the symptomatic occluded internal carotid artery.

A retrospective review of 42 patients (mean age 61.4 years) with surgically managed symptomatic internal carotid artery occlusion is reported. A standardized surgical protocol aimed at restoration of flow in the vessel was used. Presenting symptoms included hemispheric transient ischemic attacks in 68% of patients, new fixed neurological deficits in 28%, amaurosis fugax in 28%, and stroke-in-evolution in 9%. Twenty-four arteries were successfully reopened. A proximal remnant angioplasty (stumpectomy) was performed alone in nine patients or in combination with an external carotid endarterectomy in nine. In four patients with persisting symptoms who failed to achieve primary restoration of flow, a superficial temporal-to-middle cerebral artery bypass procedure was performed. The permanent surgical morbidity rate was 2% and the surgical mortality rate was 0%. Transient postoperative deficits were present in three patients (7%). Follow-up review at a mean of 40 months was obtained in 39 patients (93%). Following surgical intervention, five patients died of unrelated causes, two had neurological events consistent with a transient cerebral ischemic attack, and two had vertebrobasilar insufficiency. No patient suffered from stroke. Of the 24 successfully reopened vessels, follow-up ultrasound evaluations were obtained in 17 (73%) at a mean of 28 months after surgery. In 15 patients (88%) the vessels were widely patent, one (5.8%) had stenosis greater than 70%, and one (5.8%) showed asymptomatic reocclusion. Reopening occluded internal carotid arteries in selected patients is associated with low surgical morbidity and mortality rates. Further studies are necessary to determine the impact of this surgical therapy on the natural history of this condition.

Continuous postoperative monitoring of cortical blood flow and intracranial pressure.

A new technique to continuously monitor cortical blood flow and intracranial pressure in postoperative patients is described. A thermal diffusion flow probe with a pressure port is left in contact with the cortex at craniotomy. Postoperative intracranial pressure--cortical blood flow can be monitored and acute changes or trends are readily detected. The thermal flow probe has been previously compared with radioactive xenon (133Xe) clearance and hydrogen clearance methods of measuring cortical blood flow in animals. The technique gives a real-time quantitative indication of flow. Changes in cortical blood flow can be observed within a few seconds and the effects of treatment can be readily observed. Changes in flow due to vasospasm have been demonstrated in subarachnoid hemorrhage. It is anticipated that information learned from this method will aid in the management of patients with head trauma, tumors, and subarachnoid hemorrhage.

Percutaneous automated biopsy in the diagnosis of primary infectious spondylitis.

Three cases of primary infectious spondylitis, two caused by Staphylococcus aureus and one by tuberculosis, were diagnosed using the method previously described for automated percutaneous discectomy. All three patients, in whom biopsy using fine needle techniques previously was unsuccessful, had positive cultures from specimens obtained using the automated method. The method combines the advantages of local anesthesia and minimal morbidity with the obtaining of adequate material for culture and pathological examination.

Laser-assisted nerve repair in primates.

Studies on the peripheral nerves in rats and other species have helped in the development of laser-assisted nerve anastomosis (LANA), but offer little in evaluating the efficacy of this technique in primates. The authors present a study of LANA in the peripheral nerves of rhesus monkeys. Twelve adult rhesus monkeys underwent bilateral resection of a portion of the peroneal nerve followed by placement of autogenous sural nerve interposition fascicular grafts. The grafts were completed with conventional microsurgical suture technique on one side and with LANA on the other. At 5, 8, 10, and 12 months, the grafted nerves were evaluated for continuity, nerve conduction, and histology (both light and electron microscopy). No significant difference in continuity, conduction velocity, nerve degeneration, nerve regeneration, axon fiber number, or axon fiber density was found in any animal between grafts performed by conventional microsuture and LANA grafts. There was no difference in distal or proximal myelinated fiber density between the LANA grafts and the conventional microsuture grafts. It was concluded that LANA is as effective as microsurgical suture nerve anastomosis in a primate model of nerve repair and grafting.

Laser-assisted end-to-side anastomosis.

The milliwatt CO2 laser was used to anastomose rat carotid arteries in an end-to-side fashion, and this technique was compared to the standard suture technique. Vessels were studied at two to six weeks. All anastomosis were patient and overall, there was a 78.6 percent rate of aneurysm formation in the laser cohort, compared with 7.1 percent with suture (p less than 0.001 Fisher exact). Vessels and aneurysm histology were similar to those previously reported for the end-to-end technique.

Review of tissue welding applications in neurosurgery.

New technical advances have made feasible the utilization of low-powered laser energy for constructive applications. Experience with laser bonding of blood vessels, peripheral nerves, and dura has been obtained. These studies are summarized, and the future potential of laser bonding of tissues of the central nervous system is discussed.

Comparison of myointimal hyperplasia in laser-assisted and suture anastomosed arteries. A preliminary report.

Use of the milliwatt CO2 laser to perform microvascular anastomoses is associated with characteristic histologic changes, including intimal hyperplasia and medial necrosis. The extent of myointimal proliferation after both suture and laser-assisted vascular anastomosis was assessed in the rat femoral artery model. At 2 weeks the average intimal height of the laser-anastomosed vessels was 11.7 +/- 2.2 microns (mean +/- standard error of the mean) vs. 21.3 +/- 3.2 microns for sutured arteries (p less than 0.05). By 6 weeks the groups were equivalent (laser, 25.6 +/- 4.6 microns; suture, 17.3 +/- 1.2 microns; p, not significant). The medial changes associated with the laser-assisted method appear to inhibit the proliferative response at 2 weeks but are reversed by 6 weeks.

Aneurysm formation after low power carbon dioxide laser-assisted vascular anastomosis.

A series of 125 adult rats was operated upon to perform end-to-end anastomosis of the femoral artery using either a carbon dioxide laser or conventional suture technique. Vessels were inspected at varying time intervals grossly and microscopically. Overall, the rate of aneurysm formation for the laser group was 18.6% (21/113). Late aneurysm formation (1 week or longer after operation) was seen in 29.8% (20/67) of the laser group. No aneurysms were noted in the suture group either early or late. Histological examination of the laser-joined vessels revealed widespread necrosis and loss of elastic elements in the media. In time, abnormal spindle-shaped cells appeared in this damaged layer. Histologically, the aneurysms were indistinguishable from those reported in human cerebral aneurysm cases. This technique provides an experimental aneurysm model and lends support to the acquired/degenerative theory of human cerebral aneurysm formation.

Fibrinolytic activity following laser-assisted vascular anastomosis.

New technology has allowed tissue bonding to be feasible using carbon dioxide laser energy. Laser-assisted vascular anastomosis (LAVA) has shown comparable patency results with standard suture anastomosis, but LAVA procedures produce thermally induced transmural structural alterations. To assess functional intimal recovery in LAVA versus sutured vessels, a fibrinolytic slide technique was utilized in 21 rats which had LAVA performed in one femoral artery while the opposite limb underwent a conventional microsuture anastomosis. Conventional anastomosis had persistent fibrinolytic activity while LAVA had return of fibrinolytic activity by 48 hours. Intimal fibrinolysis inhibition following LAVA is reversible and this technique does not lead to an increased incidence of thrombosis.

Comparison of bursting strength between suture- and laser-anastomosed vessels.

The bursting strength of suture- and laser-assisted vascular anastomosis (LAVA) was assessed using a standard rat femoral artery model. Vessels were studied from 1 hour to 3 weeks. LAVA arteries consistently demonstrated lower bursting strengths than those of suture controls, with significant differences at 1 day, 3 days (P less than 0.001), and 1 weeks (P less than 0.01). Return of strength occurred in a pattern reminiscent of wound-healing models. Relatively low bursting strengths at 1 and 3 days in the LAVA cohort may explain the high aneurysm rate reported to complicate this procedure.

Microvascular anastomosis using the milliwatt CO2 laser.

The milliwatt CO2 laser was used to anastomose small vessels in a rat femoral artery model. The technique requires multiple brief applications of 60-70 mW after placement of three equidistant 10-0 nylon stay sutures. The vessel histology is described immediately and 1, 3, 7, and 21 days after the procedure. The laser effects tissue bonding through changes in the collagen of the adventitia and media. Subsequent healing consists of new collagen deposition in the adventitia and reendothelialization of the intima associated with neointimal proliferation at 3 weeks.