Acoustic neuromas present a challenging problem, with the major treatment modalities involving operative excision, stereotactic radiosurgery, observation, and fractionated stereotactic radiotherapy. The morbidity/mortality following excision may differ by patient race. To address this concern, the morbidity of acoustic neuroma excision was assessed on a nationwide level. The Nationwide Inpatient Sample from 1994–2003 was used for analysis. Only patients admitted for acoustic neuroma excision were included (International Classification of Diseases, 9th edition, Clinical Modification = 225.1; primary procedure code = 04.01). Analysis was adjusted for several variables, including patient age, race, sex, primary payer for care, income in ZIP code of residence, surgeon caseload, and hospital caseload. Multivariate analyses revealed that postoperative mortality following acoustic neuroma excision was 0.5%, with adverse discharge disposition of 6.1%. The odds ratio for mortality in African Americans compared with Caucasians was 8.82 (95% confidence interval = 1.85–41.9, P = .006). Patients with high-caseload surgeons (more than 2 excisions/year), private insurance, and younger age had decreased mortality, better discharge disposition, and lower overall morbidity (P < .04). Neither hospital caseload nor median income were predictive factors. African Americans were 9 times more likely to die following surgery than Caucasians over a decade-long analysis. Given the relatively benign natural history of acoustic neuroma and the alarmingly increased mortality rate following surgical excision among older patients, African Americans, and patients receiving care from low-caseload surgeons, acoustic neuromas in these patient populations may be best managed by a more minimally invasive modality such as observation, fractionated stereotactic radiotherapy, or stereotactic radiosurgery.
acoustic neuroma; health disparities; morbidity; mortality; neurosurgery
Objective—A recent report on head injury management from the Royal College of Surgeons of England suggests that surgeons are unsuited to the inpatient care of head injuries (ICHI) and should hand over responsibility entirely to neurosurgeons and accident and emergency (A&E) specialists. This prompted a survey of A&E consultants to establish their opinions on the current and future practice of head injury care.
Methods—Questionnaires were sent to consultant members of the British Association for Accident and Emergency medicine. Of a possible 256 A&E departments from Great Britain and Ireland with over 20 000 annual new attenders 206 (80%) replied.
Results—General surgeons contribute to ICHI for adults in 107 of 206 hospitals (52%) compared with orthopaedic surgeons in 73 of 206 (35%) and A&E consultants in 71 of 206 (34%). There was frequent criticism that surgeons are uninterested in head injury care. Fifty nine units (30%) commented on the lack of neurosurgery beds and difficulties experienced in getting patients accepted. Few hospitals seem to have well integrated rehabilitation or follow up services targeted at head injury. One in six patients with head injury admitted to a general hospital or observation ward remain after 48 hours and one in 20 stay beyond one week. Of the 132 A&E units without responsibility for ICHI 54 (41%) either wish to take on this responsibility or are willing to do so if the necessary resources are first put in place. The perceived net revenue cost required to allow 67 A&E units to take on ICHI is about 12.5 million pounds per year. This does not include the cost of further care after 48 hours, follow up or rehabilitation.
Conclusion—Only one third of A&E units at present have even part of the ICHI role recommended in the RCS report; another third are prepared to accept a new role if training and resources are provided and support is forthcoming from other specialists to take over the care after 48 hours; the remaining third are unwilling to accept responsibility for ICHI.
It is generally agreed that the successful management of a vestibular schwannoma (VS) usually involves close collaboration between a neuro-otologist and neurosurgeon. In addition, it is accepted that the experience of the team managing such tumours is one of the key determinants of outcome after surgical intervention. The aim of this study was to identify current practice in the management of such tumours amongst otolaryngologists in the UK and to observe whether such collaborative working practices exist.
MATERIALS AND METHODS
A cross sectional postal questionnaire survey of consultant members of the British Association of Otorhinolaryngologists – Head and Neck Surgeons (n = 542).
A total of 336 replies were received (62%). Of respondents, 299 consultants referred their patients to another surgeon for further management; 242 referred to another ENT surgeon (80.9%), 29 to a neurosurgeon (9.7%) and 28 to a combined team (9.4%). Twenty-eight of the responding otolaryngologists (8.6%) managed the tumours themselves, of whom 22 worked with a neurosurgeon. Of these 28 neuro-otologists, nearly two-thirds (64%) had been undertaking VS surgery for more than 10 years. The total number of patients with a VS referred to these 28 consultants during 2001 was 775, with a mean caseload of 29.8, median 23 and a range of 4 to 102 per surgeon. Seven of the 28 otolaryngologists chose their surgical approach entirely based on the size of the tumour. Eight consultants preferred the sub-occipital (SO) approach, 10 the trans-labyrinthine (TL) approach, three chose between SO and TL approaches. The majority of surgeons had a prospective, computer-based data collection and were willing to give further information about their outcomes and complications.
Amongst the otolaryngologists surveyed in the UK, we have identified 28 neuro-otologists who undertake VS surgery. The majority work with neurosurgical colleagues, confirming collaborative practice. The wide range in caseload raises the issue of training and maintaining standards and in the first instance we recommend a prospective national audit of VS management and outcomes with our neurosurgical colleagues. This would also be of value in manpower planning particularly if a minimum caseload could be identified below which results were seen to be less good.
Vestibular schwannoma; Acoustic neuroma; Audit; Management; Collaboration
An audit of surgery for acoustic neuroma was carried out to determine the frequency and nature of postoperative symptoms and their impact upon the patient's quality of life and vocation. Fifty-six patients were interviewed between 6 months and 5 years (mean 26 months) after surgical excision of an acoustic neuroma. The objective surgical results in these patients are good, with normal or near normal functional preservation rates of 80% for the facial nerve (House-Brackmann grade I/II), and 27.3% for a previously functioning acoustic nerve. Despite this there was no significant overall reduction in the reported occurrence of balance problems, tinnitus, headache and other neurological sequelae of the tumour after surgical excision. In 20% of the patients persistent symptoms, including deafness and facial weakness, had prevented the resumption of former social activities. As a result of these symptoms 8.6% of the patients were certified medically unfit for work, but of those employed preoperatively over 70% had returned to their jobs. The success of neuro-otological surgical management of acoustic neuroma is offset by some degree of chronic morbidity. Our patients expressed the need to know whether their symptoms would resolve, but were often too afraid to ask. Patients can be reassured that the majority resume their former social and vocational activities, but should be advised that some symptoms can persist or occur de novo after surgery. Our data suggest that early intervention would reduce the incidence of these troublesome sequelae.
Aim of the study
Efficacy of stereotactic radiosurgery (SRS) in the treatment in cerebral AVM's, mennigiomas, metastases, acoustic neuromas and recurrent anaplastic gliomas is well documented. The object of this work was the analysis of the results of the treatment of AVM and selected cerebral lesions with linear accelerator-based stereotactic radiosurgery.
Material and methods
The lesions included: 12 AVMs, 2 cavernomas, 27 meningiomas, 16 metastases, 5 acoustic neuromas, 16 gliomas in 78 patients. A mean radiation dose of 16Gy was delivered to the tumour or AVM margin and 12Gy to the tumours located in a ponto-cerebellar angle. Follow-up was 18 months.
Control of tumour growth or AVM was achieved in all cases after 6 months and radiological regression was observed in 20 cases after 12 months. The best results were noted in AVM's, meningiomas and neuromas.There were no new permanent deficits nor complications after radiosurgery requiring medicamentation.
Organization of SRS in Oncological Center in Bydgoszcz involving close co-operation of radiotherapist, neurosurgeon and physicist in the process of qualification and treatment planning is based on the best global standards. Preliminary results of treatment are consistent with the literature data. A longer follow-up is required to determine the long term efficacy and the toxicity of this treatment in our institution.
stereoradiosurgery; AVM's; meningiomas; metastases; acoustic schwanomas
Traditionally, visual disturbance and optic disc edema are regarded as late manifestations of acoustic neuromas indicating increased intracranial pressure as a result of obstructive hydrocephalus or a sizeable mass lesion. We report the case of a 56-year-old man who presented with visual disturbance and bilateral optic disc edema. Classic features of hydrocephalus were absent. Magnetic resonance imaging showed a large acoustic neuroma. However, there was no ventriculomegaly and at surgery intracranial pressure was normal. We suggest that cerebrospinal fluid protein may have a role in the formation of optic disc edema through a normal pressure communicating type of hydrocephalus. Furthermore, patients with acoustic neuromas and a visual disturbance related to optic disc edema may be inappropriate for treatment with stereotactic radiosurgery and should be offered early surgery to prevent visual deterioration
Acoustic neuroma; papilledema; hydrocephalus
Olfactory dysfunction usually occurs secondary to ENT causes, and most patients with olfactory problems prefer to consult an otolaryngologist. 1a some cases the ENT surgeon is required to inculcate a systematic approach while dealing with such patients in order to screen the possibility of other causes (apart from ENT). He may in turn either collaborate with another specialist (neurologist, ophthalmologist, neurosurgeon) for proper diagnostic work- up or otherwise counsel the patient in case of a benign prognosis. Thus a basic knowledge about the applied pathophysiology of olfaction for its proper clinical approach is a must for every practicing ENT surgeon. We present the gist of the experience with olfaction at the Smell and Taste Center of the University of Pennsylvania USA that is relevant to the practicing otolaryngotogist. We present the information in two complementary parts: a clinical approach and its quantification and management which will be published in a subsequent issue of this journal.
Olfaction; Anosmia; Psychophysics
Facial nerve outcomes and surgical complication rates for other cranial nerves were evaluated retrospectively after the resection of large acoustic neuromas. The charts of all patients who underwent surgical removal of an acoustic neuroma between 1992 and 2001 at New York University Medical Center were reviewed. Fifty-four patients with tumors measuring 3 cm or larger were included in the study. Four patients had neurofibromatosis type 2, two of whom underwent bilateral removal of acoustic neuromas. Translabyrinthine microsurgical removal of tumor was performed in 47 of 56 cases (84%). In all cases, EMG monitoring, improved sharp microdissection, and ultrasonic aspiration were employed. Facial nerve function was assessed using the House-Brackmann facial nerve grading system immediately after surgery and at follow-up visits. A House-Brackmann grade III or better was achieved in 90% of patients, and a grade II or better was achieved in 84% of patients. Ultimate facial nerve outcome was excellent after the surgical resection of large acoustic neuromas. Preoperative cranial nerve palsies also improved after surgery. The translabyrinthine approach for tumor removal is our treatment of choice for acoustic neuromas 3 cm or larger.
Acoustic neuroma; translabyrinthine approach; facial nerve
Objective:To evaluate the clinical results achievable using current techniques of gamma knife stereotactic radiosurgery to treat sporadic unilateral acoustic neuromas.
Methods:A retrospective review of 234 consecutive patients treated for unilateral acoustic neuromas between 1996 and 1999, with a mean (SD) follow up of 35 (16) months. Tumour control was assessed with serial radiological imaging and by the need for surgical intervention. Hearing preservation was assessed using Gardner-Robertson grades. Details of complications including cranial neuropathies and non-specific vestibulo-cochlear symptoms are included.
Results:A tumour control rate in excess of 92% was achieved, with only 3% of patients undergoing surgery after radiosurgery. Results were less good for larger tumours, but control rates of 75% were achieved for 35–45 mm diameter lesions. Of patients with discernible hearing, Gardner-Robertson grades were unchanged in 75%. Facial nerve function was adversely affected in 4.5%, but fewer than 1% of patients had persistent weakness. Trigeminal symptoms improved in 3%, but developed in 5% of patients, being persistent in less than 1.5%. Transient non-specific vestibulo-cochlear symptoms were reported by 13% of patients.
Conclusions:Tumour control rates, while difficult to define, are comparable after radiosurgery with those experienced after surgery. The complications and morbidity after radiosurgery are far less frequent than those encountered after surgery. This, combined with its minimally invasive nature, may make radiosurgery increasingly the treatment of choice for small and medium sized acoustic neuromas.
Forty acoustic neuromas have been removed surgically between 1976 and 1986. The condition was unilateral in 32 and bilateral in four. There were 31 large, four medium and five small tumours. Excision was complete in 16 and incomplete in 24. Of the incomplete removals 14 were subtotal leaving microscopic remnants, eight were partial capsular and two were intracapsular. Follow-up ranged from two months to ten years (median 3·5 years).
There was one early death in an 83-year-old. The overall incidence of post-operative complete facial paralysis was 20% but reached 55% for large tumours when excision was complete. Twenty-eight patients had hearing before operation and in eleven patients some preservation of hearing was possible (39%). In these, the excision was complete in three, subtotal in four, partial capsular in three and intracapsular in one.
Of the unilateral tumours, there have been three recurrences requiring repeat surgery. All were initially incompletely excised. Two were of an invasive nature causing considerable erosion of the petrous temporal bone making complete excision impossible. For the bilateral tumours a deliberate incomplete excision was first performed on one side to ensure preservation of hearing. Further excision on this side was then left until such time as hearing was lost. Complications included CSF otorhinorrhoea (5%), persistent but temporary nausea and vomiting (10%), meningitis (5%), facial numbness (5%) and hoarseness and dysphagia (3%).
Patients with acoustic neuroma in their only hearing ear are not frequently seen in clinical practice. Managing this group of patients is a challenge to both patient and surgeon. In this study we report on five cases of acoustic neuroma in an only hearing ear. Our decision for nonsurgical management of those patients with regular follow-up using auditory brainstem responses and magnetic resonance imaging is discussed. Other management options currently available are considered as well.
Surgery of acoustic neuroma (AN) has significantly refined over the past years due to a series of advances in diagnostics and surgical technique. Electrophysiologic investigation performed during surgery has greatly contributed to this progress, increasing the surgeon's understanding of the mechanism of damage and suggesting various changes in his or her surgical strategy.
In this context, the advantages of the retrosigmoid “en-bloc” removal of small to medium size ANs have been examined in the present study. At the ENT Department of the University of Verona, 103 subjects with AN were operated on, from January 1990 to December 1995, with a retrosigmoid-transmeatal approach. Eighteen subjects (17.4%) presented pure a intracanalar (IC) tumor and 85 (82.6%) had both IC and extracanalar (EC) involvement. All the IC tumors (n = 18) and 70 of the IC-EC neuromas with an EC size less than 25 mm are reported in this paper for a total of 88 patients. The first 48 patients were operated on via the classic procedures described in the literature, characterized by removal of the tumor after “debulking” and limited exposure of the internal auditory canal (IAC). The following 40 subjects were operated on according to the technique of “en-bloc” removal of the tumor and wide exposure of the IAC.
In the “en-bloc” group the tumor was first detached from the cerebellar flocculus and the pons, when necessary. The tumor was not debulked to preserve the anatomic relationship with the nerves and to facilitate identification, cleavage and dissection of the tumor from the neural structures. Thereafter, the posterior wall of the IAC was drilled out and opened in a circumferential range from 180 to 270°. The IAC dura was subsequently opened, and the distal end of the AN along with the vestibular nerves were identified. The vestibular nerves were sectioned in the distal portion of the IAC and dissected with the tumor from the underlying facial and cochlear nerves. Dissection continued medially to the IAC porus. The AN was progressively dissected from the cochlear and facial nerves in the cerebellopontine angle (CPA) with multiple direction maneuvers, as required by the characteristics and degree of adherence to the neural structures.
The anatomic and functional results obtained with this new procedure (“en-bloc” removal) were compared with the classic “debulking” technique. The statistical analysis shows an improvement in postoperative outcome for both auditory and facial nerve function. The “en-bloc” removal procedure along with the wide exposure of the content of the IAC and electrophysiologic monitoring of the seventh and eighth cranial nerves are, in our experience, the recommended strategies for improving outcomes in small to medium size ANs.
The relationship between cigarette smoking and incidence of acoustic neuromas and pituitary tumours is uncertain.
We examined the relation between smoking and risk of acoustic neuromas and pituitary tumours in a prospective study of 1.2 million middle-aged women in the United Kingdom.
Over 10.2 million person years of follow-up, 177 women were diagnosed with acoustic neuromas and 174 with pituitary tumours. Current smokers at recruitment were at significantly reduced risk of incident acoustic neuroma compared with never smokers (adjusted relative risk (RR)=0.41, 95% confidence interval (CI)=0.24–0.70, P=0.001). Past smokers did not have significantly different risk of acoustic neuroma than never smokers (RR=0.87, 95% CI=0.62–1.22, P=0.4). Smoking was not associated with incidence of pituitary tumours (RR in current vs never smokers=0.91, 95% CI=0.60–1.40, P=0.7).
Women who smoke are at a significantly reduced risk of acoustic neuromas, but not of pituitary tumours, compared with never smokers. Acoustic neuromas are much rarer than the cancers that are increased among smokers.
acoustic neuroma; pituitary tumour; smoking; women
Childhood radiation exposure has been associated with an increased risk for developing several neoplasms, particularly benign and malignant thyroid tumors, but little is known about the risk of developing acoustic neuromas. The aim of this study was to confirm whether there is a risk for acoustic neuromas and, if so, to determine its magnitude and duration. We investigated the time trend and dose-response relationships for acoustic neuroma incidence in a cohort of 3,112 individuals who were irradiated as children between 1939 and 1962. Most of the patients were treated to reduce the size of their tonsils and adenoids and received substantial radiation exposure to the cerebellopontine angle, the site of acoustic neuromas. Forty-three patients developed benign acoustic neuromas, forty of them surgically resected, far in excess of what might be expected from data derived from brain tumor registries. The mean dose (±SD) to the cerebellopontine angle was 4.6 ± 1.9 Gy. The relative risk per Gy was 1.14 (95% confidence interval 1.0–1.3). The earliest case occurred 20.4 years after exposure and the latest 55 years after exposure (mean 38.3 ± 10.1 years). Our study provides support for an association between acoustic neuromas and childhood radiation exposure. Although acoustic neuromas are usually benign and often asymptomatic, many cause significant morbidity. Following childhood radiation exposure, they appear after a long latency and continue to occur many decades afterward. Any symptoms of an acoustic neuroma in a patient with a history of radiation to the head and neck area should be investigated carefully, and the threshold for employing imaging should be lowered.
Acoustic neuromas; dose-response relationships; radiation-related neoplasms
an interdisciplinary concept (neurosurgery/ear, nose, and throat (ENT))
of treating acoustic neuromas with extrameatal extension via the
retromastoidal approach. To analyse whether monitoring both facial
nerve EMG and BAEP improved the functional outcome in
acoustic neuroma surgery.
METHODS—In a series of
508 patients consecutively operated on over
a period of 7 years, functional outcome of the facial nerve was evaluated according to the House/Brackmann scale and hearing
preservation was classified using the Gardner/Robertson system.
monitoring (396 of 508 operations) and continuous BAEP recording (229 of 399 cases with preserved hearing preoperatively) were performed
routinely. With intraoperative monitoring, the rate of excellent/good
facial nerve function (House/Brackmann I-II) was 88.7%. Good
functional hearing (Gardner/Robertson 1-3) was preserved in
neuroma surgery via a retrosigmoidal approach is a safe and effective
treatment for tumours with extrameatal extension. Functional results
can be substantially improved by intraoperative monitoring. The
interdisciplinary concept of surgery performed by ENT and neurosurgeons
was particularly convincing as each pathoanatomical phase of the
operation is performed by a surgeon best acquainted with the regional specialties.
There is debate on optimal techniques that reduce bile duct injury during laparoscopic cholecystectomy (LC). A national survey of Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland (AUGIS) members was carried out to determine current surgical practice for gallstones, including the use of intra-operative cholangiography (IOC) or critical view of safety to reduce the risk of bile duct injury.
SUBJECTS AND METHODS
An anonymous postal survey was sent to all 417 AUGIS members. Data on grade of surgeon, place of work (district general hospital, teaching), subspecialty, number LC per year, use of IOC, critical view of safety, and management of stones detected during surgery were collated.
There was a 36% (152/417) response – 134 (88%) from consultant surgeons (36, HPB; 106,OG; 64, DGH; 88, teaching hospital). Of these, 38% performed > 100 LC per year, 36% 50–100 LC per year, and 22% 25–50 LC per year. IOC was routine for 24%; and selective for 72%. Critical view of Calot's triangle was advocated by 82%. Overall, 55% first clip and divide the cystic artery, whereas 41% first clip and divide the cystic duct. Some 39% recommend IOC and 23% pre-oper-ative MRCP if dilated common bile duct (CBD) is noted on pre-operative ultrasound. When bile duct stones are identified on IOC, 61% perform laparoscopic CBD exploration (LCBDE), 25% advise postoperative ERCP, and 13% perform either LCBDE or ERCP. Overall, 88% (n = 134) recommend index cholecystectomy for acute pathology, and this is more likely in a teaching hospital setting (P= 0.003). Laparoscopic CBD exploration was more likely to be performed in university hospitals (P< 0.05).
A wide dissection of Calot's triangle to provide a critical view of safety is the technique most commonly recommended by AUGIS surgeons (83%) to minimise risk of bile duct injury, in contrast to 24% that recommend routine IOC. The majority (88%) of AUGIS surgeons advise index admission cholecystectomy for acute gallbladder disease.
Gallbladder disease; Intra-operative cholangiography; Calot's triangle; UK audit
A sixty-one year old man was referred with a history of progressive dysphagia, vomiting and weight loss with some back pain. Upper gastrointestinal endoscopy and biopsies revealed a gastro-oesophageal junction adenocarcinoma. Despite the absence of metastatic disease on computed tomography, positron emission tomography demonstrated multiple vertebral and sternal deposits. He was reviewed in an ENT clinic with a sudden onset of hearing loss accompanied by dizziness, but no focal neurology. Magnetic resonance imaging identified bilateral 2cm lesions at the internal auditory meatus, consistent with a diagnosis of bilateral acoustic neuromas. The patient subsequently died of carcinomatosis and, because of the potential familial significance of bilateral acoustic neuromas, a limited post-mortem examination was carried out. Unexpectedly, this revealed bilateral adenocarcinoma metastases infiltrating the internal auditory meatus affecting the acoustic nerves. The authors believe this a very rare presentation of metastatic gastric disease.
We studied the relationship of malpractice claims and the personal, educational, and practice characteristics of a sample of surgeons (n = 427). The surgeons were members of a physician-owned malpractice trust and represented all those who had fewer than 0.13 malpractice claims per year and those with more than 0.54 claims per year. Data are reported separately for orthopedic surgeons (148), obstetrician-gynecologists (115), and a mixed group of other surgeons (164). The last group included otolaryngologists, neurosurgeons, and general, vascular, thoracic, and plastic surgeons. We studied the relationship between the number of malpractice claims (ranging from no history of claims to those terminated from the trust because of high rates of claims) and the surgeon's personal, educational, and practice characteristics. The major differences were between the surgeons who were terminated because of a high number of claims and those with few or no claims. Terminated surgeons were less likely to have completed a fellowship, belong to a clinical faculty, be members of professional societies, be graduates of an American or Canadian medical school, have specialty board certification, or be in a group practice. The data also suggest that orthopedists with high numbers of claims may be less likely to have a religious affiliation or to have a registered nurse working in their office practice. These findings suggest that surgeons with lower claim rates may be more likely to manifest exemplary modes of professional peer relationships and responsible clinical behavior.
This is a case series.
We wanted to identify variations in the practice patterns among neurosurgeons and orthopedic surgeons for the management of spinal disorders.
Overview of Literature
Spinal disorders are common in the clinical practice of both neurosurgeons and orthopedic surgeons. It has been observed that despite the availability of various guidelines, there is lack of consensus among surgeons about the management of various disorders.
A questionnaire was distributed, either directly or via e-mail, to the both the neurosurgeons and orthopedic surgeons who worked at 5 tertiary care centers within a single region of Korea. The surgeons were working either in private practice or in academic institutions. The details of the questionnaire included demographic details and the specialty (orthopedic/neurosurgeon). The surgeons were classified according to the level of experience as up to 5 years, 6-10 years and > 10 years. Questions were asked about the approach to lumbar discectomy (fragmentectomy or aggressive disc removal), using steroids for treating discitis, the fusion preference for spondylolisthesis, the role of an orthosis after fusion, the preferred surgical approach for spinal stenosis, the operative approach for spinal trauma (early within 72 hours or late > 72 hours) and the role of surgery in complete spinal cord injury. The data was analyzed using SPSS ver 16. p-values < 0.05 were considered to be significant.
Of the 30 surgeons who completed the questionnaire, 20 were neurosurgeons and 10 were orthopedic surgeons. Statistically significant differences were observed for the management of spinal stenosis, spondylolisthesis, using an orthosis after fusion, the type of lumbar discectomy and the value of surgical intervention after complete spinal cord injury.
Our results suggest that there continues to exist a statistically significant lack of consensus among neurosurgeons and orthopedic spine surgeons when considering using an orthosis after fusion, the type of discectomy and the value of intervention after complete spinal injury.
Orthopedic surgeons; Neurosurgeons; Spinal trauma; Spinal stenosis; Complete cord injury
Continuous electromyographical (EMG) monitoring of the facial nerve is widely used during acoustic tumor surgery. Mechanical stimulation of the facial nerve is capable of eliciting synchronous and asynchronous EMG responses alerting the surgeon to damaging maneuvers performed on the nerve. Mechanical stimulation, however, elicits EMG responses only when the nerve has been injured by the underlying pathology or previous surgical maneuvers, and the technique is sensitive to administration of muscular blockers. In addition, EMG is unable to furnish quantitative information about the damage. The present paper illustrates an alternative technique for intraoperative facial nerve monitoring, that is, the recording of facial nerve antidromic potentials (FNAPs).
Eleven subjects operated on by acoustic neuroma surgery via a retrosigmoid approach (tumor sizes ranging from 12 to 28 mm) participated in the investigation. Bipolar electrical stimulation of the marginalis mandibulae was performed to elicit FNAPs. Stimulus intensity ranged from 2 to 6 mA with a delivery rate of 7/second. A silver-wire electrode positioned on the proximal portion of the acoustic-facial bundle was used to record action potentials. Changes in latency and amplitude of FNAPs were analyzed as a function of the main surgical steps. FNAP monitoring provided quantitative real-time information about damaging maneuvers performed on the nerve and allowed prediction of postoperative facial function.
The translabyrinthine approach is familiar to most neurosurgeons and neuro-otologists and is frequently used to remove acoustic neuromas. Some of the complications associated with this surgery include cerebrospinal fluid (CSF) leaks, meningitis, and rarely fat graft prolapse. The authors report a 60-year-old woman who underwent a translabyrinthine approach and microsurgical resection of a right-sided 1-cm acoustic neuroma. Initially, she was discharged home after an uneventful postoperative course. Four days later, she sought treatment in the emergency room complaining of headaches, dizziness, and lethargy. A computed tomographic (CT) scan showed a large right-sided subdural hygroma and right temporal lobe edema. The patient underwent burr hole evacuation of the collection and placement of a subdural drain, after which the edema in the temporal lobe and hygroma resolved. We speculate that the underlying mechanism was the result of inadvertant damage to the venous drainage and an arachnoid tear that was not appreciated during surgery. Neurosurgeons and neuro-otogists should be aware of this unusual complication of translabyrinthine surgery and its possible underlying mechanisms.
Acoustic neuroma; translabyrinthine; subdural hygroma
This study reports the inter-surgeon variability in manual selection of the anterior and posterior commissures (AC and PC). The study also investigates the effect of this variability on the localization of targets like STN, Vim and GPi. The additional effect of variation in the selection of the mid-plane on target localization is also evaluated.
43 neurosurgeons (38 attendings, 5 residents/fellows) were asked to select the AC and the PC points (as routinely used for stereotactic neurosurgical planning) on two MRI scans. The corresponding mid-commissural points (MCP) and target coordinates were calculated.
The collected data show that the MCP point is more reliable than either the AC or the PC points. This data also show that, even for experienced neurosurgeons, variations in selecting the AC and the PC point results in substantial variations at the target points: 1.15 ± 0.89mm, 1.45 ± 1.25mm, 1.21 ± 0.83 for the STN, Vim, and GPi, respectively for the first MR volume and 1.08 ± 1.37mm, 1.35 ± 1.71mm, 1.12 ± 1.17mm for the same structures for the second volume. These variations are larger when residents/fellows are included in the data set.
The data collected in this study highlights the difficulty of establishing a common reference system that can be used to communicate target location across sites. It indicates the need for the development and evaluation of alternative normalization methods that would permit specifying targets directly in image coordinates or the development of improved imaging techniques that would permit direct targeting.
inter-surgeon variability; anterior and posterior commissures; manual selections; localization; deep brain stimulation
BACKGROUND: The treatment and prognosis of non-small cell lung cancer, and assessment of the results of treatment, depend on accurate perioperative staging. The extent to which this is carried out in the United Kingdom is unknown. METHODS: A postal questionnaire survey was undertaken in 1990 to determine the perioperative staging practices of cardiothoracic surgeons in the United Kingdom. RESULTS: Replies from 77 surgeons, who between them performed about 4833 pulmonary resections a year for lung cancer, were analysed. Forty four per cent of surgeons, operating on 43% of the patients, do not perform computed tomography of the thorax or mediastinal exploration before surgery. They may therefore embark on a thoracotomy for stage III disease. At thoracotomy 45% of surgeons, operating on 40% of patients, do not sample macroscopically normal lymph nodes. They may therefore understage cases as N0/N1 when there is at least microscopic disease in mediastinal lymph nodes. CONCLUSIONS: The staging of lung cancer in the United Kingdom in 1990 appears in many instances to be inadequate. There should be a more organised approach to perioperative staging so that prognosis may be assessed and comparisons between groups of patients can be made.
The number of neurosurgeons per million population is much lower in Europe than in the USA, where the point prevalence of neurosurgeons doubled between 1963-87. Results of a 1987 survey of USA neurosurgical practice show that surgery filled 25% of total time in professional activity. Of all cases treated, 64% were spinal disorders and 24% were intracranial disorders. Use of a relative value scale for neurosurgical procedures makes possible a rough and ready estimate of a neurosurgeon's weekly aggregate workload. However, the concept of a mean surgical workload must be examined within the context of the known variation of case mix and volume of surgical services in different practices.
Tumors occurring in the infratemporal region present a surgical challenge and access osteotomies of the facial skeleton is the answer to access these deeply situated, inaccessible tumors of the head and neck. Various approaches have been devised for their better exposure and it is our expertise as maxillofacial surgeons to provide surgical access by transmaxillary, transzygomatic and transmandibular approaches. We followed this concept in our institute and report here two case reports. The first is a 45-year-old female who presented with right facial pain and temporal swelling due to schwannoma in the right infratemporal region extending into middle cranial fossa. This was jointly treated by a team of neurosurgeons, maxillofacial surgeons and ENT surgeons by right temporal craniotomy, right transmandibular and transzygomatic approach. The second is a rare tumor occurring in a 26-year-old male with the chief complaint of right frontal headache and diplopia. The tumor was excised via access through the zygomatic arch and lateral orbital wall; diagnosed later as Rosai Dorfmans disease. No recurrence was seen at follow-up period of 2 years. These approaches help to reduce the surgical morbidity. Thus, oral and maxillofacial surgeons form a vital role in the multidisciplinary approach to provide access to difficult anatomic locations.
Access osteotomy; infratemporal; Rosai Dorfmans disease; schwannoma