Endoscopic cranial base surgery: classification of operative approaches

OBJECTIVE

Endoscopic cranial base surgery is a minimal access, maximally aggressive alternative to traditional transfacial, transcranial, or combined open cranial base approaches. Previous descriptions of endoscopic approaches have used varying terminology, which can be confusing to the new practitioner. Indications for surgery are not well defined. Our objective was to create a comprehensive classification system of the various approaches and describe their indications with case examples.

METHODS

We prospectively compiled a comprehensive database of our endonasal endoscopic operations, detailing the nasal sinus transgressed, the cranial base approach, and the intracranial target for the first 150 consecutive cases performed at our institution. All cases were performed collaboratively by a neurosurgeon and an otolaryngologist.

RESULTS

We categorized the endonasal endoscopic cranial base operations into four nasal corridors, nine cranial base approaches, and 13 intracranial targets. Each of the various approaches is described in detail and illustrated with case examples. Pathology encountered included pituitary tumor (50%), meningocele/encephalocele (14%), craniopharyngioma and Rathke cleft cyst (10%), meningioma (8%), chordoma (5%), esthesioneuroblastoma (2%), and other (11%).

CONCLUSION

Endonasal endoscopic cranial base surgery is a minimal access, maximally invasive alternative to open transcranial cranial base approaches for specific indications. A clear understanding of the possible approaches is facilitated by an awareness of the nasal corridors and intracranial targets.

The pulmonary artery catheter in Australasia: a survey investigating intensive care physicians' knowledge and perception of future trends in use

A survey was conducted to assess the knowledge and trends of use of the pulmonary artery catheter amongst intensive care practitioners in Australasia. A 31-item multiple choice questionnaire, identical to one previously trialled in studies in the United States and Europe, was distributed to all registered intensive care specialists and trainees working in intensive care units in Australasia. Five-hundred-and-forty-one questionnaires were distributed and 151 (27.9%) were returned, with an average mark of 82.7% +/- 9.3% and a range of 53.3 to 100%. Total score was significantly associated with years of experience in intensive care (P < 0.04), number of pulmonary artery catheters inserted (P < 0.015) and whether or not the respondent had passed the Joint Faculty of Intensive Care Medicine examination (P < 0.01). Scores were significantly higher amongst trainees (P < 0.0001) and physicians who had passed the Joint Faculty of Intensive Care Medicine examination (P < 0.0001). Overall, 44.9% of respondents indicated their use of the pulmonary artery catheter was decreasing, with 42.6% indicating their use was the same over the past five years. Sixty-one percent of respondents indicated they either agreed or strongly agreed with the statement that the use of echocardiography should supersede the use of the pulmonary artery catheter by intensive care specialists in the future. We concluded that in this study, knowledge of the pulmonary artery catheter and its use is better in Australasia than in previous studies in North America and Europe. The majority of respondents in Australasia believe that echocardiography will supersede the use of the pulmonary artery catheter in the future.

AAV-mediated delivery of the caspase inhibitor XIAP protects against cisplatin ototoxicity

HYPOTHESIS

Delivery of the gene encoding X-linked inhibitor of apoptosis (XIAP) using an adeno-associated viral (AAV) vector can protect against cisplatin-mediated ototoxicity.

BACKGROUND

Cisplatin is a widely used chemotherapeutic agent with significant ototoxic side effects. One possible mechanism of toxicity is apoptotic death of many cochlear cell types. Acute treatment with inhibitors of caspases- enzymes critical for apoptosis- has been shown to prevent hearing loss in vivo, but is too short-acting for therapeutic use. Gene therapy provides a specific and chronic means of delivering potential therapeutic gents. Introducing an anti-apoptotic gene into the cochlea could provide long-term prophylaxis against the ototoxic effects of cisplatin.

METHOD

Two groups of rats were treated with unilateral injection into the round window of AAV harboring a gene encoding either XIAP or green fluorescent protein (GFP). After at least two months of gene expression, auditory-brainstem-response (ABR) threshold shifts and outer-hair-cell (OHC) number were measured in these two groups of animals after 72-hour treatment with cisplatin.

RESULTS

Consistent with previous reports, uninjected and AAV.GFP-injected ears displayed profound ABR threshold elevations and OHC loss after cisplatin treatment. Ears that had been injected with AAV encoding XIAP, however, were significantly protected from these effects: cisplatin-induced ABR-threshold shift and hair-cell loss were attenuated by as much as 78% and 45%, respectively, when compared with contralateral (untreated) ears.

CONCLUSION

XIAP delivery to the cochlea can protect against the audiometric changes and hair-cell loss associated with cisplatin ototoxicity. The efficacy, specificity, and duration of the protective effects make this a potentially attractive therapeutic paradigm.

Resolution of Severe Ischemia–Reperfusion Injury Post–Lung Transplantation After Administration of Endobronchial Surfactant

BACKGROUND

Ischemia-reperfusion injury (IRI) is a prominent cause of primary graft failure after lung transplantation and is associated with an altered surfactant profile. Experimental animal studies have found that replacement with exogenous surfactant administered via fiber-optic bronchoscopy (FOB) enhanced recovery from IRI with improved pulmonary compliance and gas exchange after lung transplantation. We report our clinical experience with FOB instillation of surfactant in severe IRI after human lung transplantation.

METHODS

This study is a retrospective review of 106 consecutive lung or heart-lung transplants performed at a single institution. Severe IRI was defined as diffuse roentgenographic alveolar infiltrates, worsening hypoxemia and decreased lung compliance within 72 hours of lung transplantation. One vial of surfactant (20 mg/ml phospholipid) was instilled into each segmental bronchus upon diagnosis of IRI.

RESULTS

Six patients (5 bilateral sequential and 1 re-do heart-lung transplant), mean age 46 years, were diagnosed with IRI and surfactant was administered at a mean of 37 hours (range 2.3 to 98) post-transplant. Mean graft ischemia time was 376 minutes (range 187 to 625) and cardiopulmonary bypass time 174 minutes (range 0 to 210). Mean Pao(2) [mm Hg]/Fio(2) ratio before and 48 hours after surfactant instillation was 70 and 223, respectively. Significant resolution of radiologic infiltrates was evident in all cases within 24 hours. Successful extubation occurred at a mean of 13.5 days and survival is presently 100% at 19 months (range 3 to 54).

CONCLUSIONS

Bronchoscopic instillation of surfactant improves oxygenation and prognosis after severe IRI in lung transplant recipients. It represents a cost-effective, relatively non-invasive therapeutic alternative to extracorporeal membrane oxygenation.

Endoscopic biopsy sampling of tophaceous gout of the odontoid process

✓The authors present the case of a 71-year-old man who presented with neck pain, a history of gout, and a mass in the dens. Results of transoral endoscopic biopsy sampling demonstrated tophaceous gout. The patient was treated medically and the pain resolved. Tophaceous gout isolated in the dens is extremely rare and should be considered in the differential diagnosis of masses in this region. With the aid of transoral or transnasal endoscopic biopsy sampling, the diagnosis can be reached in a minimally invasive manner.

Anterior approaches to fusion of the cervical spine: a metaanalysis of fusion rates

Object

Anterior cervical discectomy (ACD), ACD with interbody fusion (ACDF), ACDF with placement of an anterior plate system (ACDFP), corpectomy, and corpectomy with plate placement are used to fuse the cervical spine. The authors conducted a metaanalysis of studies published after 1990 in which fusion rates achieved with each procedure were reported for patients with degenerative disease at one, two, and three disc levels.

Methods

Twenty-one papers each included data on at least 25 patients. In each of the 21 studies the average clinical follow up was more than 12 months, and the results were evaluated according to radiographic evidence of fusion and delineated by the number of levels fused. Chi-square and Fisher exact tests were used for comparisons. The mean age of the patients was 46.7 years, 46.6% were female, and the mean follow-up period was 39.6 months. The studies included 2682 patients and the overall fusion rate was 89.5%. For single disc–level disease, fusion rates were 84.9% for ACD, 92.1% for ACDF, and 97.1% for ACDFP (p = 0.0002). For two disc–level disease, fusion rates were 79.9% for ACDF, 94.6% for ACDFP, 95.9% for corpectomy, and 92.9% for corpectomy with plate placement (p = 0.0001). For three disc–level disease, fusion rates were 65.0% for ACDF, 82.5% for ACDFP, 89.8% for corpectomy, and 96.2% for corpectomy with plate placement (p = 0.0001). The use of anterior plates significantly improved fusion for one-level (p < 0.0001), two-level (p < 0.0001), and three-level (p < 0.05) ACDF. There was no significant difference in fusion rates between two-level ACDF and corpectomy with plate placement.

Conclusions

The anticipated fusion rate is one of several factors that may guide surgical decision making. Anterior cervical decompression and fusion results in high fusion rates. The results of the authors' study show that regardless of the number of levels fused, the use of an anterior cervical plate system significantly increases the fusion rate. For two-disc–level disease, there was no significant difference between ACD with a plate system or corpectomy with a plate system. For three-disc–level disease, however, the evidence suggests that corpectomy with plate placement is associated with higher fusion rates than discectomy with plate placement.

TREATMENT OF RUPTURED INTRACRANIAL ANEURYSMS

OBJECTIVE

The outcomes reported in the International Subarachnoid Aneurysm Trial (ISAT), a multicenter, prospective, randomized trial to directly compare surgical clipping with endovascular coiling as treatments for ruptured intracranial aneurysms, have been misinterpreted by many to indicate the superiority of coiling to surgical clipping in all instances. To better understand the results of ISAT and their implications for practice patterns, we compared the ISAT results with the results of other published studies regarding the treatment of ruptured intracranial aneurysms.

METHODS

Data from 19 published studies were compared with each other and with ISAT results. Outcomes examined were overall rates of mortality, rebleeding, poor outcome (disability and death), procedural complication rates, and rates of reoperation and nontotal occlusion.

RESULTS

In the 19 published studies, mean procedural complication rates were similar (surgical clipping, 11%; endovascular coiling, 9%); ISAT did not report procedural complications. ISAT rates were within the range of the other studies for overall mortality, total rebleeding, and poor outcome. Reoperation rates in the other studies were similar to those of ISAT (endovascular coiling, 12.5%; surgical clipping, 3.4%). The ISAT rate for less than 100% occlusion for endovascular coiling (6%) was below the range in the other studies (8.3–70.4%).

CONCLUSION

Discrepancies with the results of other published studies, procedural limitations in study design, and lack of some data endpoints and subgroup analysis raise concerns regarding extracting generalizations from the conclusions of ISAT. We think that the creation of a national registry would further the study of treatment of ruptured intracranial aneurysms.

Hyponatremia in the neurosurgical patient: epidemiology, pathophysiology, diagnosis, and management

OBJECTIVE

Hyponatremia is an important and common electrolyte disorder in critically ill neurosurgical patients that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological cause is vital because it dramatically alters the treatment approach.

METHODS

We review the epidemiology and presentation of patients with hyponatremia, the pathophysiology of the disorder with respect to sodium and fluid balance, and the diagnostic procedures for determining the correct cause.

RESULTS

We then present the various treatment options, including discussion of one of the newest groups of agents, the arginine vasopressin receptor antagonists, currently under study for the treatment of hyponatremia in neurosurgical patients.

CONCLUSION

Hyponatremia is a serious comorbidity in neurosurgical patients that requires particular attention as its treatment varies by cause and its consequences can affect neurological outcome.

Complication Avoidance in Vertebral Column Spine Tumors

The role of surgery for metastatic spine disease is palliative with the goals of achieving excellent neurologic and functional status, spinal stability, pain relief, and local tumor control. Although patients with metastatic spine tumors often have numerous medical and oncologic issues, careful perioperative planning and surgical techniques can help limit complications and help improve patient outcomes significantly.

The use of recombinant activated factor VII for refractory bleeding post complex cardiothoracic surgery

We reviewed the outcome following use of recombinant activated factor VII (rVIIa) in patients with major bleeding post cardiothoracic surgery in our unit between January 2002 and July 2004. The unit consists of 16 cardiothoracic intensive care beds in a public metropolitan teaching hospital which serves as a referral centre for heart and lung transplant surgery. Patients with refractory bleeding following cardiothoracic surgical procedures who were treated with rVIIa were identified. A total of 12 episodes of rVIIa use were recorded in ten patients, including three episodes with ventricular assist devices, and 5 heart and/or lung transplants. The median dose used was 85 microg/kg. Chest tube drainage decreased in all patients following administration of rVlIIa; median chest tube drainage decreased from 445 ml/h to 171 ml/h (P = 0.03). Despite cessation of bleeding, mortality was high when rVIIa was used after more than 24 hours. In six episodes, despite early rVIIa use (within six hours), continued bleeding necessitated return to theatre, where a surgical source of bleeding was found. In this small retrospective study, rVIIa significantly reduced bleeding that was refractory to standard blood product transfusion. In this series of patients, those that did not respond to rVIIa early in the postoperative phase were found to have a surgical source of bleeding.

Uroscopic rainbow: modern matula medicine

Visual inspection of a patient's urine has long been used by physicians, with colour recognised as having important clinical implications. In this review the authors will revisit this ancient pastime with relevance to contemporary medical practice.

Survival following ventricular free wall rupture: a case series

Ventricular rupture occurs in 10% of acute myocardial infarctions and is associated with significant mortality. We describe two cases of ventricular rupture post myocardial infarction who survived. We highlight salient points in their diagnosis and management and review the existing literature to determine what constitutes optimal management in these difficult cases.

Aspergillus flavus endocarditis--to prevaricate is to posture

Fungal endocarditis represents both a diagnostic and therapeutic challenge to the treating team. The critical care physician will see a rising incidence as older and more immuno-compromised patients are being supported in their intensive care units. Aspergillus sp. endocarditis represents less than 25% of all cases of fungal endocarditis and is associated with a mortality of around 80%. Early diagnosis may assist with definitive management. We review a case of Aspergillus endocarditis, and review the literature as to optimal methods of detection, imaging modalities of choice, and management, both surgical and medical.

Experiences of anticholinesterase pesticide poisonings in an Australian tertiary hospital

There is limited information regarding the management and outcomes of patients presenting with anticholinesterase pesticide poisoning in Australia. Patients presenting to a tertiary referral hospital with anticholinesterase exposures were identified by discharge coding. The medical records of each patient were retrospectively reviewed. Based on clinical outcome, patients were classified as severe or non-severe poisonings. Forty-one presentations were noted between 1990 and 2003. Eight patients (20%) had severe poisoning of which tachycardia, fasciculations with weakness and metabolic acidosis were common manifestations. The diagnosis was delayed in four patients due to the absence of a clear history, which did not influence patient outcomes or put hospital staff at risk of nosocomial poisoning. The median length of hospital stay was prolonged in severe poisonings (20 days) compared to 12 hours in other patients. Two cases of intermediate syndrome were attributed to fenthion and diazinon, and one case of delayed polyneuropathy to trichlorfon. Cholinesterase activities were performed in only 49% of presentations. The overall mortality was 2.4% (1 death) and the mortality in patients with severe poisoning was 12.5%. The incidence of anticholinesterase poisoning in Australia is low. These outcomes were favourable and comparable with other published data. Measures to enhance the knowledge of medical staff supplemented by validated treatment protocols should be developed. For less significant exposures, an emphasis on adequate documentation of cholinergic signs and cholinesterase activities is necessary for rapid triage and may also have potential forensic implications if not performed.

The use of Acticoat™ in neonatal burns

PURPOSE

To evaluate the safety and efficacy of Acticoat use in primary burn injuries and other skin injuries in premature neonates.

PROCEDURES

An audit of eight premature neonates who sustained burn injuries and other cutaneous injuries from various agents were treated with Acticoat. Serum silver levels were measured in three neonates. Wounds were assessed for infection and blood cultures were taken where sepsis was suspected.

FINDINGS

Neonates ranged from 23 to 28 weeks gestation (weight: 578-1078 g). Causative injury mechanisms included: alcoholic chlorhexidine, alcoholic wipes, electrode jelly, extravasated intravenous fluids, artery illuminator, temperature probe and adhesive tape removal. Total burned body surface area ranged from 1 to 30%. All neonates were treated with Acticoat dressing changed every 3-7 days. All wounds re-epithelialised by day 28 and scar management was not required. There were four mortalities secondary to problems associated with extreme prematurity. Serum silver levels ranged from 0 to 1 micromol/L. There were no wound infections or positive blood cultures during the treatment period.

CONCLUSIONS

Acticoat is a suitable dressing for premature neonates who have sustained burn injury, with the advantage of minimal handling as the dressing need only be changed every 3-7 days.

Decompressive craniectomy as a therapeutic option in the treatment of hemispheric stroke

Even though severe hemispheric stroke represents a small subtype of ischemic stroke, the extreme morbidity and mortality necessitate aggressive management strategies to improve outcome. Decompressive craniectomy is an important therapeutic tool with demonstrated effects in significantly reducing intracranial hypertension and mortality from herniation related to cerebral edema and elevated intracranial pressure. Its effect on functional outcome and quality of life varies, but there is evidence to suggest beneficial effects in younger patients and in patients treated earlier. Although more prospective data are required to further identify specific indications for the procedure, it represents an important tool in treatment of nondominant hemispheric stroke.

Use of osteopromotive growth factors, demineralized bone matrix, and ceramics to enhance spinal fusion

Recently developed materials that can enhance fusion rates for posterolateral lumbar arthrodesis may be used alone or in combination with autogenous bone grafts. Novel osteopromotive growth factor preparations are currently under scrutiny; these include autogenous growth factor concentrate, bovine bone-derived osteoinductive protein, and recombinant human MP52. Demineralized bone matrix products may enhance or extend grafts. However, few studies, especially prospective randomized clinical trials, have assessed their efficacy, so it is difficult to compare formulations. Ceramics have been evaluated in animal studies and human clinical trials for a variety of applications in spinal surgery. These materials function best as bone graft extenders or as bioactive osteoinductive material carriers in posterolateral lumbar fusions. They have the advantage of variable porosity, low cost, and ease of manufacture. Hydroxyapatite/tricalcium phosphate ceramics have been shown to perform as well as autogenous bone grafts but with fewer complications.

Partial liquid ventilation for preventing death and morbidity in adults with acute lung injury and acute respiratory distress syndrome

BACKGROUND

Acute lung injury (ALI), and acute respiratory distress syndrome (ARDS), are syndromes of severe respiratory failure. Adults with ALI or ARDS have high mortality and significant morbidity. Partial liquid ventilation (PLV) may be better (i.e., cause less lung damage) for these patients than other forms of respiratory support. Uncontrolled studies in adults have shown improvement in gas exchange and lung compliance with partial liquid ventilation.

OBJECTIVES

To assess whether partial liquid ventilation reduces morbidity and mortality in adults with ALI or ARDS.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library Issue 2, 2004; MEDLINE (1966 to May 2004); and CINAHL (1982 to May 2004); intensive care journals and conference proceedings; reference lists and unpublished literature.

SELECTION CRITERIA

Randomized controlled trials which compared partial liquid ventilation with other forms of ventilation, in adults (16 years old or greater) with ALI or ARDS, reporting one or more of the following: mortality; duration of mechanical ventilation, respiratory support, oxygen therapy, stay in the intensive care unit, or stay in hospital; infection; long term cognitive impairment or health related quality of life; long term lung function; or cost.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated the quality of the relevant studies and extracted the data from the included studies.

MAIN RESULTS

Problems with the inadequacy of the primary report of the one included study do not allow us to report any quantitative results for patients with ALI or ARDS. The only outcome we considered to be of clinical significance and reported for all enrolled patients (i.e., patients with ALI and ARDS and less severe respiratory insufficiency) was 28 day mortality. There was no statistically significant difference between groups for this outcome with a relative risk for 28 day mortality in the PLV group of 1.15 (95% confidence intervals of 0.64 to 2.10).

REVIEWERS' CONCLUSIONS

There is no evidence from randomized controlled trials to support or refute the use of partial liquid ventilation in adults with ALI or ARDS; adequately powered, high quality randomized controlled trials are still needed to assess its efficacy. Clinically relevant outcome measures should be assessed (especially mortality at discharge and later, duration of respiratory support and hospital stay, and long term cognitive and quality of life outcomes) and the studies should be published in full.

Thermal injuries in three children caused by an electrical warming mattress

Peroperative hypothermia is recognized to increase mortality and morbidity, and the paediatric anaesthetist faces specific challenges resulting from the increased body surface to volume ratio, particularly in smaller children. We describe three children who were consecutive patients on one operating list and sustained severe thermal injuries. These were due to a malfunctioning electrical heating mat, despite appropriate use and monitoring by the attending anaesthetist. It is rare for thermal warming devices to cause injury. We review the use of heating mats, and suggest modifications in their manufacture which may minimize the risks associated with heating devices.

Hot beverage scalds in Australian children

Our objective was to compile data on the mechanism and severity of injuries associated with hot beverage burns in children. We identified 152 children over a 3-year period who attended a tertiary level burns center, representing 18% of all children treated. Their median age was 17.5 months and median body surface area burned was 4% (range, 0.25% to 32%). Significantly, 52% of children required admission, 18% received a split skin graft, and 26% required long-term scar management. In 70% of all cases, the mechanism of injury was the child pulling the hot beverage over himself or herself. In 80% of incidents, a primary care giver witnessed the injury. These findings indicate that scalding from hot beverages carries significant morbidity and is an important pediatric public health issue. It is clear that further research towards effective education programs for primary caregivers is warranted.

Acute hepatic failure caused by an acute aortic dissection with cardiac tamponade: a case report

An acute cardiac tamponade from any cause may result in rapid deterioration of hepatic function in a previously healthy patient. We describe a case of an acute ascending aortic dissection that presented as acute hepatic failure, due to an acute cardiac tamponade and severe right heart failure. The differential diagnosis of the aetiology of acute liver failure is extensive and includes poisonings, vascular obstruction and sepsis, particularly on the background of decompensated liver disease. Many of these conditions are associated with hypotension. The acute presentation in our patient, combined with the lack of a characteristic history delayed the diagnosis of a proximal (type A) dissection with tamponade and subsequent hepatic failure. Severe right-sided heart failure as a result of conditions such as cardiac tamponade should be excluded in patients presenting with acute hepatic failure of unknown aetiology.