|SYMPOSIUM - POLYTRAUMA MANAGEMENT
|Year : 2013 | Volume
| Issue : 1 | Page : 34-39
Comprehensive contemporary management of otolaryngologic trauma in polytrauma patients
Rupa Mehta, Nitin Nagarkar, Ripudaman Arora
Department of Otorhinolaryngology, AIIMS, Raipur, Chhattisgarh, India
|Date of Web Publication||23-Sep-2013|
Department of Otorhinolaryngology, AIIMS, Raipur, Chhattisgarh
Source of Support: None, Conflict of Interest: None
Patients with polytrauma can sustain significant injuries to the ears , nose and neck. Injuries in this region can present with life threatening bleeding and airway problems. Prompt and optimum management of these injuries is required for a successful outcome. In this article we enumerate the various otolaryngologic injuries and their management.
Keywords: Airway, ear trauma, nasal injury, neck injury, otolaryngologic trauma, temporal bone trauma
|How to cite this article:|
Mehta R, Nagarkar N, Arora R. Comprehensive contemporary management of otolaryngologic trauma in polytrauma patients. J Orthop Traumatol Rehabil 2013;6:34-9
|How to cite this URL:|
Mehta R, Nagarkar N, Arora R. Comprehensive contemporary management of otolaryngologic trauma in polytrauma patients. J Orthop Traumatol Rehabil [serial online] 2013 [cited 2019 Jan 21];6:34-9. Available from: http://www.jotr.in/text.asp?2013/6/1/34/118748
| Introduction|| |
Polytrauma or multiple trauma is a medical term describing the condition of a person who has been subjected to multiple traumatic injuries.  Polytrauma patients' management warrants a team approach and should be geared toward comprehensive evaluation, timely diagnosis of critical injuries and their optimum management.
Although the head, face and neck comprise only 12% of the total body surface area exposed during impact, injuries sustained in these areas are more likely to be fatal.  The neck is a compact and complex conduit of various organ systems (airway, vascular, neurological and gastrointestinal) anteriorly only protected by the skin and subcutaneous tissue. Hence, life-threatening complications can occur from airway compromise and hemorrhage from major cervical vessels. The outer, middle and inner ear may be affected in polytrauma and though ear injuries are not life-threatening, but they have significant functional audiologic and vestibular sequelae requiring concerted rehabilitation measures. Injuries to nose and oral cavity may result in exsanguinating hemorrhage necessitating immediate resuscitation and control measures. Fractures of nasal framework and sinuses if not optimally managed can lead to esthetic deformity.
Besides, head and neck remains an important region in which injuries are often diagnosed late or missed during the initial assessment. Hence, the otolaryngologist has an important role to play as a part of the trauma team for optimum management of the polytrauma patient. Not only is he/she the definitive expert as far as the airway management is concerned, but his role is of paramount importance in the timely diagnosis and management of critical skullbase, otologic, laryngeal and craniocervical arterial injury. Hence, it has been aptly stated that otolaryngology is not just another specialty in the wars of the twenty-first century. It is one of - if not the - most crucial subspecialties in the care of the injured. 
In this article, we enumerate the various otolaryngologic injuries sustained in polytrauma patients and their management.
| Neck Injury|| |
Patients with polytrauma can sustain blunt or penetrating neck injuries. Stab injuries, gunshot wounds result in penetrating neck wounds. Neck has been divided into three zones for the purpose of management of penetrating injuries. Zone 1-From the thoracic inlet to cricoid cartilage; zone 2-From cricoid cartilage to the angle of mandible; zone 3-Above the angle of mandible. Incidence of vascular injuries is higher in zone 1 and zone 3 while esophageal injuries and concomitant chest injuries are commonly seen in zone 1 injuries. Overall, zone 2 is the most commonly injured area (47%), followed by zone 3 (19%) and zone 1 (18%). In 16% of cases, there is involvement of more than 1 zone. 
The various sources of blunt neck trauma are motor vehicle collisions, clothesline injury and strangulation. The laryngotracheal airway and cervical spine are most affected in blunt neck trauma. Esophageal injuries in the form of pharyngeal mucosal tears are also infrequently seen. Vascular injuries are uncommon in blunt neck trauma but are associated with high mortality.
Neck houses various vital structures in a small anatomical area; the signs and symptoms depend on the structure affected. Vascular injury to carotids or its branches may result in active bleeding, expanding hematoma, pseudoaneurysm formation, pulse deficit, vascular bruit; shock and deterioration in neurological status may occur due to the reduction in cerebral perfusion. Laryngotracheal injury results in hoarseness, stridor, respiratory distress, hemoptysis, airway obstruction and subcutaneous emphysema. Esophageal injury is often asymptomatic and may result in dysphagia, odynophagia, hematemesis and subcutaneous emphysema and if not timely recognized and treated may ultimately lead to the neck or mediastinal abscess and sepsis.
| Management|| |
The initial assessment has to be followed according to the advanced trauma life support (ATLS) guidelines following the ABCDE algorithm. Depending on the clinical presentation of the patient, the decision is made regarding surgical intervention or observation. Surgical management has evolved from the era of World War 1 when non-surgical management was practiced with high mortality rates to the era of World War 2 when mandatory neck exploration for all neck wounds that penetrated the platysma was practiced to the present era when selective neck exploration is practiced at most centers with various studies demonstrating equivalent mortality rates as mandatory neck exploration. Several series of mandatory explorations yielded a negative rate of 40-60%.  Presence of "hard" signs of major vascular or laryngotracheal injuries mandates an immediate operation without any delay for definitive investigations. If time permits chest radiograph and contrast enhanced computed tomography (CECT) neck should be done to gauge the extent of damage.
In stable patients, depending on the presentation, various investigations like radiographs of chest, neck, helical CECT neck, angiography, esophagoscopy, laryngo tracheoscopy, dye studies, may be required. Depending on the findings, further plan of management is decided.
| Laryngotracheal Trauma|| |
The incidence of laryngotracheal injuries is rare but is frequently associated with cervical spine injuries. Patients present with skin abrasions, bruising, laryngeal tenderness and distortion of the anterior neck anatomy. The signs and symptoms are hoarseness, dysphagia, pain, dyspnea, hemoptysis and symptoms of airway obstruction such as stridor or tachypnea, drooling and cervical subcutaneous emphysema or crepitation. The American College of Surgeons' ATLS protocol suggests three clinical findings, which indicate fracture of laryngeal framework: Hoarseness, subcutaneous emphysema and palpable fracture. 
Fuhrman et al.  have reported that the most common symptoms in laryngeal trauma are tenderness and subcutaneous emphysema and that the patient's inability to tolerate the supine position, which is commonly noticed in severely injured patients, can be an important symptom with which we should consider immediate tracheostomy without performing laryngoscopic examination. Tracheostomy has been recommended as a measure of airway control because orotracheal intubation can lead to iatrogenic complications in patients with fracture of the larynx [Table 1]. 
The thyroid cartilage is most commonly affected in laryngeal fractures followed by cricoid cartilage and arytenoid cartilages. CT with 1 mm thickness cuts with multiplanar reconstructions helps in diagnosis of fractures lines and fragments as well as suspected dislocation on transverse scans. Soft-tissue windows images help in the evaluation of mucosal or vocal cord asymmetry and swelling. Fiberoptic nasolaryngoscopy is used for a preliminary assessment of the extent of trauma and vocal cord mobility in stable patients.
All surgical patients after securing airway should undergo panendoscopy intraoperatively for a detailed examination of the injury before surgical repair. Surgical repair is required for lacerations involving the free margin of the vocal fold, large mucosal lacerations, exposed cartilage, multiple and displaced cartilage fractures, avulsed or dislocated arytenoids cartilages and vocal fold immobility situations.
For patients with cricotracheal separation, airway is secured with tracheostomy and primary reanastomosis of cricoid and tracheal rings is done from posterior to anterior with a combination of 3-0 absorbable and non-absorbable suture. Endolaryngeal stenting is performed when extensive lacerations involving the anterior commissure are present or when multiple cartilaginous fractures are present that cannot be stabilized adequately with open reduction.
| Ear Injury|| |
The ear is housed in the temporal bone complex, which is a non-weight-bearing region. The goal of management of the temporal bone fractures is to restore functional deficits and not reducing and fixing bone fragments. Common injuries requiring the surgical management include hearing loss, facial nerve dysfunction and cerebrospinal fluid (CSF) leaks. Temporal bone fractures can be longitudinal or transverse or mixed pattern; otic capsule sparing or otic capsule involving. Most often, treatment of the temporal bone trauma can be delayed after life-threatening injuries are treated. Emergent intervention is required in two situations following temporal bone trauma. Brain herniation (encephalocele) into the middle ear, mastoid or external acoustic meatus requires immediate neurologic and medical stabilization and CT scanning to allow planning for emergent surgical correction. Massive bleeding from intra-temporal carotid artery laceration, though a rare complication of the temporal bone trauma requires emergent intervention. Balloon occlusion of the vessel by an interventional radiologist is generally faster than surgical ligation and repair in this situation.
Laceration, avulsion or hematoma of the pinna and collapse or stenosis of external auditory canal may occur in accidents or falls. The pinna can be burnt and damaged by flying debris during blast exposures. If not treated in time, these can result in cosmetic deformity, cauliflower ear, external canal stenosis. Presence of blood or CSF in the external auditory canal (EAC), step deformity may be a telltale sign of the temporal bone fracture.
Tympanic membrane (TM) rupture and/or ossicular disruption may occur as a result of blast injuries to the ear While other organs in the body need pressure gradients of 56-76 lb/inch 2 for damage to occur, the ear is much more sensitive, with ruptures occurring in 50% of adults at 5 lb/inch 2 (approximately 185 dB peak pressure level) depending on the noise spectra and duration. , Most traumatic TM perforations heal spontaneously except when they get infected or when there is a subtotal or total perforation. Small parts of squamous epithelium may get implanted in the middle ear as a result of the TM rupture resulting into subsequent cholesteatoma formation.
| Inner Ear|| |
Causes of sensorineural hearing loss (SNHL) post blast injury to the ear include structural damage to the inner and outer hair cells, disruption of the oval or round window. The incidence of pure SNHL, is 35-100% in blast injured patients. ,,,,, The audiometric configuration of hearing in blast exposed patients is a high-frequency hearing loss at one or more frequencies, although in few patients, flat configurations with mild to severe hearing loss or profound deafness may be present.
| Facial Nerve Palsy|| |
Longitudinal fractures of the petrous bone account for 90% of all fractures and causes facial nerve injury in 10-25% of cases, whereas transverse fractures of the petrous accounts for 10% of all temporal bone fractures and causes facial nerve injury in 30-50% of cases. In both cases, injury to the facial nerve is usually in the perigeniculate region. Bilateral facial nerve paralysis (FNP) may be seen in longitudinal fractures. Post-traumatic FNP, especially bilateral FNP is likely to be missed if associated with severe traumatic brain injury. In cases where it is diagnosed, it warrants a thorough evaluation including high resolution computed tomography of the temporal bone and electrophysiological testing. Apart from definite indications of surgery such as immediate onset FNP with fracture line running through fallopian canal or bony fragment impinging on nerve, gradual improvement can be expected in most cases with conservative management. Delayed facial nerve palsy is mostly due to edema and is treated with high dose steroids with further intervention based on results of the electrodiagnostic testing. Kim et al.  reported that the patient with traumatic FNP who had nerve conduction studies consistent with a poor prognosis regained considerable facial function after early surgical intervention; however, late exploration did not result in a positive outcome. In cases where surgery is required, middle fossa approach is used to decompress the nerve in the temporal bone in patients with intact hearing, whereas translabyrinthine approach is used if the hearing is absent.
| Nose and Sinuses|| |
Injuries to facial skeleton includes soft-tissue injuries of face, fractures of the facial skeleton, nasal bone fracture, naso-orbito-ethmoid (NOE) fractures, maxillary, mandibular fractures, frontal bone fractures, and is dealt by multiple specialties-oral and maxillofacial surgeons, plastic surgeons, otolaryngologic surgeons. Facial injuries are often associated with skull base injuries and are complicated by CSF leaks, orbital injuries and lacrimal system, ocular and optic nerve injuries. Neurosurgical and Ophthalmologic consultation are frequently sought for associated injuries.
Nasal fractures are commonly encountered facial fractures and may occur in isolation or be associated with other facial fractures. The bony - cartilaginous framework of the nose provide esthetic and structural support to the midface and airway; hence proper evaluation and management is mandatory to prevent nasal deformity and nasal airway compromise. Associated septal hematoma needs to be drained immediately to prevent cartilaginous necrosis and subsequent saddling. Higuera et al. Algorithmic management approach of nasal trauma (Kelley et al.) is useful for planning management of nasal trauma.
Nasal trauma classification
- Type I injury restricted to soft tissue.
- Type IIa simple, unilateral non-displaced fracture.
- Type IIb simple, bilateral non-displaced fracture.
- Type III simple displaced fracture.
- Type IV closed comminuted fracture.
- Type V open comminuted fracture or complicated fracture*
- *Type II to IV fracture with CSF rhinorrhea, airway obstruction, septal hematoma, crush injury, numbness, severe displacement or NOE midface involvement.
Management of nasal trauma has to be decided based on multiple factors including (1) age of the patient, (2) time since injury, (3) necessity for acute versus delayed reduction, (4) choice of anesthesia and (5) approach (open vs. closed reduction).
Kelley et al.  have suggested an algorithmic management approach based on the above classification [Figure 1].
|Figure 1: Algorithmic management approach of nasal trauma (Kelley et al.)|
Click here to view
The NOE complex is the confluence of the frontal sinus, ethmoid sinuses, anterior cranial fossa, orbits, frontal bone and nasal bones.
Markowitz et al. (1991) devised a classification system based on the degree of central fragment injury. Each fracture type is subclassified as either unilateral or bilateral.
- Type I fractures represent a single non-comminuted central fragment without medial canthal tendon disruption.
- Type II fractures involve comminution of the central fragment, but the medial canthal tendon remains firmly attached to a definable segment of bone.
- Type III fractures are uncommon and result in severe central fragment comminution with disruption of the medial canthal tendon insertion.
General goals of surgical management include protection of orbital and intracranial contents, prevention of early and late complications (e.g., blindness, epiphora) and restoration of esthetic facial contour (e.g., normal intercanthal distance, orbital volume).
Exposure of the fracture is done by sublabial, transconjunctival and coronal incisions and the fractured segments are fixed with miniplates or transnasal wires.
| Parotid Gland Injury|| |
Parotid gland can sustain blunt trauma or penetrating injury by assault weapon or by shattered glass during a roadside accident or perforating wounds by firearms. Facial injuries inferior to a line extended from the tragus to the upper lip should raise concern for parotid injury. Injury to the parotid gland can manifest as facial nerve neuropathy, hematoma, salivary fistula, sialocele or pseudocyst formation. Associated injuries of Parotid duct, external auditory canal and temporomandibular joint may be present. Injuries posing the greatest risk of damage to Stensen's duct include those anterior to the posterior border of the masseter and necessitate exploration. Morestin reported a series of 62 cases of parotid fistulas after battlefield wounds.  Initially, treatment consisted of surgically draining the fistula into the oral cavity. Later a simpler solution was found: the proximal duct was ligated, causing the gland parenchyma to atrophy and saliva production to cease.
Landau and Stewart, in their series of 14 cases of penetrating injuries, concluded that systemic probanthine, intravenous fluids, a nil by mouth regimen and external pressure would produce a resolution of symptoms, even in the presence of a fistula or sialocele.  In their series, antibiotics were given only if there was clinical evidence of infection and surgical exploration was reserved for those patients presenting within 24 h of the injury. A series by Lewis and Knottenbelt also concluded that conservative management was adequate for parotid duct injuries.  Botulinum toxin has also been used in the management of post-traumatic sialoceles and salivary fistulae.
The most clinically significant aspect of penetrating injury to the parotid gland is disruption of the facial nerve. Therefore, facial nerve function should be carefully documented and recorded. Youngs and Walsh-Waring reported three patients with facial palsy after open trauma, all of whom underwent surgical exploration of the nerve and all of whom subsequently achieved a good recovery. 
Approximately, 80% of CSF leaks result from non-surgical trauma, 16% from surgical procedures and the remaining 4% are non-traumatic. Of the traumatic leaks, more than 50% are evident within the first 2 days, 70% within the 1 st week and almost all present within the first 3 months. , Traumatic CSF leaks occur most commonly in young males and complicate 2% of all head traumas and 12-30% of all basilar skull fractures.  Leaks from the Anterior skull base are more common than middle or posterior leaks, due to the firm adherence of the dura to the anterior basilar skull. The most common sites of CSF rhinorrhea following accidental trauma are the sphenoid sinus (30%), frontal sinus (30%) and ethmoid/cribriform (23%). Temporal bone fractures with resultant CSF leak can present with CSF otorrhea or rhinorrhea via egress through the Eustachian tube with an intact TM. Fain et al. presented an analysis of 80 cases of trauma to the cranial base. They stated that there are five types of frontobasal trauma. Type I involves only the anterior wall of the frontal sinus. Type II involves the face (craniofacial disjunction of the Lefort III Type or crush face), extending upward to the cranial base and to the anterior wall of the frontal sinus, because of the facial retrusion. Type III involves the frontal part of the skull and extends down to the cranial base. Type IV is a combination of Types II and III, whereas Type V involves only ethmoid or sphenoid bones. In this study, CSF leaks were infrequent in Types I and II, but occurred more frequently in Types III, IV and V, which included a dural tear in each case. Therefore, when a patient presents with one of these fractures a CSF leak should be suspected. Once there is suspicion of CSF rhinorrhea, the fluid should be collected and sent for biochemical studies and b2 transferrin and b trace protein and imaging performed to localize the site of the leak. A trial of conservative management of 3-5 days should be given before taking the patient for definitive repair. Patients are advised strict bed rest, head elevation, to refrain from coughing, sneezing, nose blowing and straining or Valsalva maneuvers. Stool softeners, antiemetics and antitussives may be prescribed. Yilmazlar et al.,  in their series of 81 cases of traumatic CSF fistula have noted that the overall rate of cessation with conservative treatment was 39.5% when used for 3 days. Resolution with conservative treatment of CSF fistulas involving temporal bone origin was 60%, whereas anterior skull base defects resolved 26.4% of the time with conservative treatment. If conservative management is extended to 7 days, resolution rates improve to 85%, again with leaks of the temporal bone origin healing with a significantly higher rate than those of anterior skull base origin.  In cases in whom leak persists, CSF diversion procedures may be required. Addition of CSF diversion to conservative measures raises success rates to 70-90% with the average duration of drainage being 6.5 days, , The added advantage of these procedures is that they can be performed at the bedside, even if patients are not stable enough to go to the operating room. Lumbar drains are also used perioperatively as an adjunctive treatment to increase the success rates following a variety of surgical repairs.  Various approaches - transcranial, transnasal, endoscopic endonasal have been described for definitive repair of traumatic CSF fistula.
Head and neck trauma management are challenging and there are various areas where discrepancy of opinion still persists. Debate still continues on various areas viz.-selective versus mandatory neck exploration for penetrating neck injury, use of prophylactic antibiotics in post-traumatic CSF rhinorrhea and whether the early surgical repair prevent meningitis in patients with traumatic CSF leaks. Head and neck trauma are common and research should be directed in development of personal protective gear to help prevent injury and death from facial and neck trauma in war and for civilian use.
| References|| |
|1.||President's Project: Support for VAMC Poly Trauma Centers (From the American Legion auxiliary website). |
|2.||Pitone ML, Attia MW. Patterns of injury associated with routine childhood falls. Pediatr Emerg Care 2006;22:470-4. |
|3.||Berkowitz G. Otolaryngologists on the front lines. ENT Today. 2007. |
|4.||Demetriades D, Theodorou D, Cornwell E, Berne TV, Asensio J, Belzberg H, et al. Evaluation of penetrating injuries of the neck: Prospective study of 223 patients. World J Surg 1997;21:41-7. |
|5.||Jarvik JG, Philips GR 3 rd , Schwab CW, Schwartz JS, Grossman RI. Penetrating neck trauma: Sensitivity of clinical examination and cost-effectiveness of angiography. AJNR Am J Neuroradiol 1995;16:647-54. |
|6.||Committee on Trauma, American College of Surgeons. Advanced Trauma Life Support for Doctors. Chicago, IL: American College of Surgeons; 2004. p. 42-3. |
|7.||Fuhrman GM, Stieg FH 3 rd , Buerk CA. Blunt laryngeal trauma: Classification and management protocol. J Trauma 1990;30:87-92. |
|8.||Schaefer SD. Primary management of laryngeal trauma. Ann Otol Rhinol Laryngol 1982;91:399-402. |
|9.||Kronenberg J, Ben-Shoshan J, Modan M, Leventon G. Blast injury and cholesteatoma. Am J Otol 1988;9:127-30. |
|10.||Zajtchuk JT, Philips YY. Effects of blast overpressure on the ear. Ann Otol Rhinol Laryngol Suppl 1989;140:5. |
|11.||Lew HL, Jerger JF, Guillory SB, Henry JA. Auditory dysfunction in traumatic brain injury. J Rehabil Res Dev 2007;44:921-8. |
|12.||American Academy of Pediatrics. In: Foltin GL, Schonfeld DJ, Shannon MW, editors. Pediatric Terrorism and Disaster Preparedness: A Resource for Pediatricians. Rockville (MD): AHRQ Publication No. 06(07)-0056, Agency for Healthcare Research and Quality; 2006. Available from: http://www.ahrq.gov/research/pedprep/. [Last accessed on 2013 June 25 |
|13.||Mrena R, Pääkkönen R, Bäck L, Pirvola U, Ylikoski J. Otologic consequences of blast exposure: A Finnish case study of a shopping mall bomb explosion. Acta Otolaryngol 2004;124:946-52. |
|14.||Persaud R, Hajioff D, Wareing M, Chevretton E. Otological trauma resulting from the Soho Nail Bomb in London, April 1999. Clin Otolaryngol Allied Sci 2003;28:203-6. |
|15.||Perez R, Gatt N, Cohen D. Audiometric configurations following exposure to explosions. Arch Otolaryngol Head Neck Surg 2000;126:1249-52. |
|16.||Van Campen LE, Dennis JM, Hanlin RC, King SB, Velderman AM. One-year audiologic monitoring of individuals exposed to the 1995 Oklahoma City bombing. J Am Acad Audiol 1999;10:231-47. |
|17.||Kim J, Moon IS, Shim DB, Lee WS. The effect of surgical timing on functional outcomes of traumatic facial nerve paralysis. J Trauma 2010;68:924-9. |
|18.||Higuera S, Lee EI, Cole P, Hollier LH Jr, Stal S. Nasal trauma and the deviated nose. Plast Reconstr Surg 2007;120 Suppl 2:64S-75. |
|19.||Kelley BP, Downey CR, Stal S. Evaluation and reduction of nasal trauma. Semin Plast Surg 2010;24:339-47. |
|20.||Morestin M. Contribution à l'etude du traitement des fistules salivaires consécutives aux blessures de guerre. Bull Mem Soc Chir Paris 1917;43:845-55. |
|21.||Landau R, Stewart M. Conservative management of post-traumatic parotid fistulae and sialoceles: A prospective study. Br J Surg 1985;72:42-4. |
|22.||Lewis G, Knottenbelt JD. Parotid duct injury: Is immediate surgical repair necessary? Injury 1991;22:407-9. |
|23.||Youngs RP, Walsh-Waring GP. Trauma to the parotid region. J Laryngol Otol 1987;101:475-9. |
|24.||Loew F, Pertuiset B, Chaumier EE, Jaksche H. Traumatic, spontaneous and postoperative CSF rhinorrhea. Adv Tech Stand Neurosurg 1984;11:169-207. |
|25.||Kerman M, Cirak B, Dagtekin A. Management of skull base fractures. Neurosurg Q 2002;12:23-41. |
|26.||Friedman JA, Ebersold MJ, Quast LM. Post-traumatic cerebrospinal fluid leakage. World J Surg 2001;25:1062-6. |
|27.||Fain J, Chabannes J, Péri G, Jourde J. Frontobasal injuries and csf fistulas. Attempt at an anatomoclinical classification. Therapeutic incidence. Neurochirurgie 1975;21:493-506. |
|28.||Yilmazlar S, Arslan E, Kocaeli H, Dogan S, Aksoy K, Korfali E, et al. Cerebrospinal fluid leakage complicating skull base fractures: Analysis of 81 cases. Neurosurg Rev 2006;29:64-71. |
|29.||Bell RB, Dierks EJ, Homer L, Potter BE. Management of cerebrospinal fluid leak associated with craniomaxillofacial trauma. J Oral Maxillofac Surg 2004;62:676-84. |
|30.||Shapiro SA, Scully T. Closed continuous drainage of cerebrospinal fluid via a lumbar subarachnoid catheter for treatment or prevention of cranial/spinal cerebrospinal fluid fistula. Neurosurgery 1992;30:241-5. |