Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 83 pdf

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Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 83 pdf

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from 16–20 weeks. However, spina bifida may be missed, particularly in the L5–S2 region [24, 44]. Magnetic Resonance Imaging MRI is the modality of choice for prenatal imaging Since its advent, MRI has become the imaging modality of choice. While ultraso- nography is an excellent screening procedure, it requires considerable expertise to interpret, whereas MRI is definitive. Prenatal MRI can also be used to charac- terize the Chiari II and other associated malformations [24]. Prenatal imaging studies help to predict neurological deficits. Postnatal Diagnostic Tests Imaging Studies For evaluation of the spinal cord malformations and tethered cord syndrome, the most helpful diagnostic images are obtained by MRI, which provides excellent details of anatomy and characterization of soft tissue anomalies [39, 58]. Other imaging studies, including standard radiographs and CT, may also be helpful. Plain radiographs will show vertebral anomalies. A CT scan is particularly useful for the evaluation of bony anomalies and split cord malformations [34, 39]. Magnetic Resonance Imaging The best demonstration of the entire craniospinal axis is made by MRI and should be performed after the birth whenever possible. The T1- and T2-weighted MR images in the sagittal and axial planes provide excellent demonstrations of the anatomopathological characterization of the components of the malforma- tion, i.e. relationship between placode and nerve roots and other associated sequences (Chiari II, hydrocephalus, hydromyelia) [32]. Investigate the entire neural axis when spinal malfor- mations are suspected Before theMRIera, it had been assumed that after untethering, there would be upwardmigrationofthespinalcord,whichinfactdoesnotoccurinmostcases [19]. Postoperative follow-up MRI almost always shows low-lying conus and should not be confused with a “retethering” [10]. The diagnosis of retethering and decision for untethering requires clinical judgment. Attempts to improve conventional MRI techniques, including the use of prone positioning [10], upright MRI and dynamic phase MRI, have been investigated but await valida- tion through further studies [19]. Urodynamic Studies Urodynamic studies may show low bladder capacity and overflow incontinence, and may serve as a baseline for postoperative follow-up [15]. Treatment It is important to recognize tethering of the spinal cord as early as possible. Once the neurological deficits have occurred, many patients will not have recovery of lost functions. Tethered cord should be treated as soon as possible Although the underlying causes of tethered cord vary, thesigns and symptoms of tethering are generally the same. Individuals with spinal malformations need both surgical and medical lifelong management which should be provided by a multidisciplinary team. Malformations of the Spinal Cord Chapter 29 815 Asymptomatic patients with tethered cord should be instructed to avoid the fol- lowing activities because of the risk of a potential sudden neurological deteriora- tion [57]: deep bending (touching the toes, high leg kicking) holding any weight while standing that causes back and leg pain sitting position such as the Buddha pose sitting in a slouching position horse riding skiing at high altitude (might produce spinal hypoxia) Valsalva-type maneuvers to prevent spinal venous congestion In Utero Treatment Fetalsurgeryforspinal dysraphism is feasible After a diagnosis of fetal spinal dysraphism, there are two choices: either termi- nation or fetal surgery [24]. The period of legal termination differs between countries. The first cases of in utero open spinal dysraphism repair were done in 1994 but proved unsatisfactory [3]. In 1997, in utero repair by hysterotomy was reported [3, 20]. Up to 2004, more than 200 in utero, open spinal dysraphism clo- sures are estimated to have been done [20]. Urodynamic and lower extremity function seem to besimilar in infants treated in utero and postnatally [20]. Com- pared with historical controls, infants treated in utero have a lower incidence of Chiari II andhydrocephalus requiring shunting [3, 20]. Delivery via cesarean sec- tion is preferred [28]. Postnatal Surgery Open spinal dysraphisms must be treated surgically as early as possible (Table 6): Table 6. General aims of surgery untether the spinal cord prevent infections repair of the dural/cutaneous defect restore normal anatomy as far as possible Closure of the spinal lesions is usually done within 48–72 h of birth [20, 28, 58]. If there are signs of hydrocephalus, a shunt isplaced at the same time as the lesion is closed. There are some standard rules for closure of open spinal dysraphism, but in many cases the surgeon must vary the technique on the basis of individual anat- omy. The surgical microscope should assist in defining distorted anatomy and associated pathologies in great detail. The interested reader is referred to repre- sentative articles in the literature and textbooks [26, 28, 31, 50, 58]. Open Spinal Dysraphism After careful and extensive dissection of the sac from the neural placode, neural tissue is repositioned into the dural sac to preserve functional neural tissue. There is no proven technique for closure of myelomeningocele at the time of the original surgery that will prevent retethering. However, there are some tech- niques that may minimize the amount of retethering that occur: The neural pla- code can be folded over and anatomically made into a tube by suturing the edges of theopen placode together. It does not prevent retethering, butitseems to make the surgery for untethering easier. Sometimes the use of vascularized flaps may be necessary. 816 Section Spinal Deformities and Malformations Closed Spinal Dysraphism In the cases of closed spinal dysraphisms, the associated lesions need careful dis- section. In split cord malformation, after opening the dura, complete excision of the bony spur or fibrous septum is performed. A thickened or fatty filum termi- nale is cut and also released to detether the cord. Sometimes, closure of the dura is a problem. In these cases, it is necessary to use fascia lata or synthetic dura sub- stitutes to repair the dural deficiency. Wound closure is done in multiple layers in order to prevent liquor leak. Tethered Cord Syndrome Surgery for tethered cord must be early In open spinal dysraphism, short- and long-term survival has increased with improvements in medical and surgical management. Surgical intervention for tethered spinal cord must be as early as possible to prevent progressive neuraltis- sue damage. Once neurological function is lost it may never recover. The value of early prophylactic surgical intervention in tethered cord is evident in the litera- The only effective treatment is surgical untethering ture [16, 35, 48].Theonly effective treatment is surgical untethering of the spinal cord from theunderlying cause. The goal of the untethering surgery is to stop any further neurological deterioration [35, 48]. One of the current controversies with respect to tethered cord management includes the untethering of the spinal cord in asymptomatic patients. The majority of authors recommend prophylactic sur- gery [16, 48]. The decision about the surgical technique should be made individually on a case-by-case basis. The special details of the various surgical techniques are beyond the scope of this chapter. Several excellent textbooks exist in the field of spinal malformations–tethered cord surgery. Interested readers are referred to representative articles in the literature andthese textbooks and atlases [26,28, 31, 50, 58]. Untethering is generally a safe surgical procedure in experienced hands [16]. Complications include infection, bleeding, and damage to the functional part of the spinal cord. Although the causes of tethered cord vary, the general principles of the surgery are similar. The operating microscope and microsurgical technique are necessary for bet- ter visualization and precise dissection. Different instrumentations are used to perform the dissection including endoscopy, ultrasonic aspirator, and lasers; one method is not necessarily better than the others, and the surgeon usually has her or his own preference based upon their experience [8, 10, 48]. Intraoperative neuromoni- toring and the microscope are invaluable intraoperative aids Various intraoperative monitoring techniques such somatosensory evoked potentials (SSEPs), lower extremity and anal sphincter EMGs, external anal sphincter monitoring and nerve root stimulation studies are helpful to identify functional elements [15, 58]. But it remains valid that the most important factor for a good postoperative result is the experience of the surgeon in handling these complex anomalies [12]. Retethering remains a risk and requires reexploration if signs of tethered cord syndrome are seen. In secondary tethered cord the untethering procedure usually involves open- ing and dissecting the scar from the prior closure. Malformations of the Spinal Cord Chapter 29 817 Recapitulation Epidemiology. Neural tube defects are the most common congenital abnormalities of the central nervous system. Classification. Spinal cord malformations can be classified based on the pathomorphological pre- sentation as presenting with and without a back mass. A secondary discriminator is related to the coverage with skin in the presence of a back mass. The vast majority of spinal cord malformations re- sult in a tethering of the spinal cord. We differenti- ate primary tethered cord as a result of spinal mal- formations and secondary tethered cord which re- sults from a surgical intervention. Pathogenesis. Spinal cord malformations (=spinal dysraphism) arise from defects occurring in the em- bryological stages of gastrulation (weeks 2 – 3), neurulation (weeks 3–6) and caudal regression. There is an increased risk of spinal malformations in pregnant women who are taking certain drugs. An increased risk of spinal malformation is associat- ed especially with exposure to valproic acid or carb- amazepine. Patients with myelomeningocele and myelocele almost always have associated Chiari II malformation. Hydromyelia may occur in as many as 80% of these patients, and may be localized or extend through the whole cord. It may cause rapid development of scoliosis if left untreated. Classical- ly tethered cord is defined as having the tip of the conusbelowtheL2discspaceand a pathologically elongated spinal cord. However, in the medical lit- erature, there are many publications of tethered cord syndrome with the conus in a normal position. Clinical presentation. Tethered cord–spinal cord malformations are usually diagnosed at birth or early infancy (open spinal dysraphism, closed spi- nal dysraphisms with back mass) but sometimes are discovered in older children or adults. Tethered spinal cord should be highly suspected and consid- ered in the differential diagnosis of patients who present with cutaneous midline abnormalities, low back pain, lower extremity and foot deformi- ties, subtle neurological deficits, and bladder and sexual dysfunctions. Irreversible neuronal damage canoccurwhenthereissuddenstretchingoftheal- ready chronically tethered conus. Diagnostic work-up. The prenatal examination en- compasses maternal serum -fetoprotein examina- tion and ultrasound. The advent of diagnostic mo- dalities such as MRI has increased the number of tethered spinal cord diagnoses and will require awareness and prompt multidisciplinary manage- ment of the syndrome before neuronal loss ad- vances. Since multiple tethering lesions and cere- bral anomalies coexist in a significant number of cases, it is absolutely necessary to investigate these patients with craniospinal MRI to screen the entire neuroaxis. Prenatal treatment. It is important to counsel women of childbearing age about the need to take dietary supplements containing foliate before be- coming pregnant. Up to 70 % of spina bifida cases can be prevented by periconceptional folic acid supplementation. Intrauterine surgery is possible but superiority over postpartum surgery needs to be established. Postnatal treatment. Individuals with spinal malfor- mations need both surgical and medical lifelong management which should be provided by a multi- disciplinary team. Open spinal dysraphism requires immediate surgery (within 2– 3 days postpartum). Main goal of surgery is to untether the spinal cord, prevent infections, repair the dural/cutaneous de- fect, and restore normal anatomy as far as possible. Mainly the goal of the untethering is to stabilize the progressive neurological deterioration but some authors recommend a prophylactic untethering procedure for asymptomatic patients. Early unteth- ering, when minimum or mild symptoms are detect- ed,isessentialfortetheredcordsyndrometreat- ment. Surgical intervention for tethered cord in- volves identification of the tethering lesion, release of the spinal cord and reconstruction of the normal anatomy as soon as possible. The operating micro- scope and microsurgical technique are necessary for better visualization and precise dissection. Intra- operative neuromonitoring is useful. 818 Section Spinal Deformities and Malformations Key Articles Yamada S (1996) Tethered cord syndrome. The American Association of Neurological Surgeons,ParkRidge,Illinois This isa first andexcellent textbook on tethered cord syndrome. There are 16chapters on embryology,pathophysiology,diagnosis,imaging,andtherapythatcoverallaspectsof the syndrome. All chapters are superb didactically not only for neurosurgeons but also for orthopedic surgeons, neurologists, pediatricians, and urologists. Pang D (1995) Disorders of the pediatric spine. Raven Press, New York This book covers perfectly all aspects of childhood spine, beginning with a section on embryology and biomechanics, and bridging the philosophies of orthopedic surgeons and neurosurgeons by including chapters written by these two specialties. Alarge section is devoted to the many congenital malformations with deeply detailed definitions, nice photos and drawings of operative techniques. Tortori-Donati P, Rossi A, Cama A (2000) Spinal dysraphism: a review of neuroradiolog- ical features with embryological correlations and proposal fo r a new classification. Neu- roradiology 42(7):471 – 91 This paper presents the correlation between anatomy, embryology, neuroradiology and clinical findings of spinal dysraphism and formulates a working classification of these malformations. Mitchell LE, Adzick NS, Melchionne J, Pasquariello PS, Sutton LN, Whitehead AS (2004) Spina bifida. Lancet 364:1885 – 1895 This is an excellent review which highlights the key features of spina bifida. References 1. Arai H, Sato O, Okuda O, Miyajima M,Hishii M, Nakanishi H,Ishii H (2001) Surgical experi- ence of 120 patients with lumbosacral lipomas. Acta Neurochir (Wien) 143:857–864 2. 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Haberl H, Tallen G, Michael T, Hoffmann KT, Bennedorf G, Brock M (2004) Surgical aspects and outcome of delayed tethered cord release. Zentralbl Neurochir 65:161–167 9. Hoffman HJ (1996) Indications and treatment of the tethered spinal cord. In: Yamada S (ed) Tethered cord syndrome. The American Association of Neurological Surgeons, Park Ridge, Illinois, pp 21–28 10. Hudgins RJ, Gilreath CL (2004) Tethered spinal cord following repair of myelomeningocele. Neurosurg Focus 16:E7 11. Iskandar BJ, Oakes WJ (1999) Occult spinal dysraphism. In: Albright AL, Pollack IF, Adelson PD (eds) Principles and practice of pediatric neurosurgery. Thieme, New York, pp 321–351 12. Iskandar BJ, Fulmer BB, Hadley MN, Oakes WJ (2001) Congenital tethered spinal cord syn- drome in adults. Neurosurg Focus 10:e7 13. Knierim DS (1996) Epidermoid and dermoid tumors associated with tethered spinal cord. In: Yamada S (ed) Tethered cord syndrome. The American Association of Neurological Sur- geons, Park Ridge, Illinois, pp 125–133 14. Kumar R, Singh SN (2003) Spinal dysraphism: Trends in northern India. Pediatr Neurosurg 38:133–145 15. Lapsiwala SB, Iskandar BJ (2004) The tethered spinal cord syndrome in adults with spina bifida occulta. Neurol Res (7):735–740 Malformations of the Spinal Cord Chapter 29 819 16. van Leeuwen R, Notermans NC, Vandertop P (2001) Surgery in adults with tethered cord syn- drome: Outcome study with independent clinical review. J.Neurosurg (Spine 2) 94:205–209 17. Manfredi M, Donati E, Magni E, Salih S, Orlandini A, Beltramello A (2001) Spinal dysra- phism in an elderly patient. Neurol Sci 22:405–407 18. McLone DG, Dias MS (1991) Complications of meningomyelocele closure. Pediatr Neuro- surg:17:267–73 19. Michelson DJ, Ashwal S (2004) Tethered cord syndrome in childhood: Diagnostic features and relationship to congenital anomalies. Neurol Res 7:745–753 20. 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Childs Nerv Syst 19:96–103 35. Schmidt DM, Robinson B, Jones DA (1990) The tethered spinal cord, etiology and clinical manifestations. Orthopaed Rev XIX(10):870–876 36. Schneider S (1996) Tethered cord syndrome: The neurological examination. In: Yamada S (ed) Tethered cord syndrome. The American Association of Neurological Surgeons, Park Ridge, Illinois, pp 49–54 37. Selcuki M, Coskun K (1998) Management of tight filum terminale syndrome with special emphasis on normal level conus medullaris. Surg Neurol 50:318–322 38. Tortori-Donati P, Rossi A, Biancheri R, Cama A (2001) Magnetic resonance imaging of spi- nal dysraphism. Top Magn Reson Imaging 12(6):375–409. Review. 39. Tortori-Donati P, Rossi A, Cama A (2000) Spinal dysraphism: a review of neuroradiological features with embryological correlations and proposal for a new classification. Neuroradiol- ogy 42:471–91. Review 40. Tubbs RS, Oakes WJ (2004) Can the conus medullaris in normal position be tethered? 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Anasthesio Intensivmed Nottfallmed Schmerzther 36(6):384–7 Malformations of the Spinal Cord Chapter 29 821 30 Cervical Spine Injuries Michael Heinzelmann, Karim Eid, Norbert Boos Core Messages ✔ Cervical spine injuries account for about one- third of all spinal injuries and the most com- monly injured vertebrae are C2, C6 and C7 ✔ A neurological deficit occurs in about 15% of all spinal injuries ✔ Atlas burst fractures result from axial compres- sion in slight extension, dens fractures are due to a combination of horizontal shear and verti- cal compression, and traumatic spondylolisthe- sis is caused by an extension-distraction injury ✔ The flexed lower cervical spine is susceptible to ligamentous injuries without fractures on axial loading, which can result in bilateral facet sub- luxation or luxation. Additional rotation leads to unilateral dislocations ✔ Whiplash associated disorders, which fre- quently result from rear-end collisions, tend to become chronic in about half of injured indi- viduals. Late whiplash disorders have strong similarities with chronic pain syndrome ✔ The assessment of vital and neurological func- tions is a priority in cervical injuries ✔ Polytraumatized and head injury patients are at very high risk of having sustained a cervical injury ✔ Standard radiography is indicated in cervical injuries according to the Canadian C-Spine Rule or NEXUS criteria ✔ CT is the imaging modality of choice for the evaluation of cervical fracture/dislocation but MRI can add important information with regard to neural compromise and injury to the disco- ligamentous complex ✔ Patients with a cervical sprain/strain or whip- lash injury should be treated with reassurance about the absence of serious pathology (after diagnostic assessment), education about the prognosis, early return to normal activities and physical exercises (if needed) ✔ Fracture reduction by traction and/or urgent decompression is recommended in patients with progressive or incomplete SCI and persis- tent spinal cord compression ✔ Traction must not be applied before ruling out atlanto-occipital or discoligamentous dislocation ✔ Occipital condyle fractures, atlanto-occipital dislocation and atlantoaxial instabilities are rel- atively rare after trauma but must not be over- looked ✔ Unstable burst (Jefferson) fractures of the atlas must be treated by rigid external fixation or surgery (C1/2 or Judet screw fixation) ✔ Type I and III dens fractures can be treated non- operatively by rigid external fixation but Type II fractures require a surgical approach because of the high non-union rate ✔ Type II dens fractures are treated by anterior screw fixation or posterior atlantoaxial instru- mented fusion in cases with delayed union or advanced age ✔ Traumatic spondylolisthesis of the axis can be treated non-operatively in Type I fractures, while Type II and III require anterior or posterior instrumented fusion ✔ Lower cervical spine fractures can be classified into Type A (compression), Type B (distraction) and Type C (rotation) injuries ✔ Type A injuries are usually treated conserva- tively in the absence of severe anterior column involvement and neurological deficits ✔ Type B and Type C injuries should be treated operatively by anterior or posterior instru- mented fusion ✔ Most lower cervical spine injuries can be treated successfully by an anterior approach ✔ Facet dislocation injuries require closed or open reduction and adequate fixation with rigid external or internal fixation Fractures Section 825 ab c d e f g hi Case Introduction This 20-year-old male patient had a mo- tor vehicle accident with a polytrauma. Extraspinal injuries included a closed head injury (Glasgow Coma Scale 6) with shearing injuries and consecutive intra- cranial pressure monitoring for 2 weeks, a thorax injury with lung contusions, bilat- eral hematopneumothorax, manubrium sterni fracture, and multilevel spinal inju- ries with fractures of the vertebrae T6, T8, T10, T12 and L3. The thoracolumbar spinal fractures were treated conservatively. In addition, a traumatic spondylolisthe- sis C2 (Type Effendi II) was initially treated conservatively ( a). After 6 weeks, the instability of the C2 injury became obvi- ous, as shown in the standard lateral radiographs ( b)andtheCTscan(c). The small bony fragment indicates a rupture of the disc C2/C3. The fractures of the pedicles C2 are shown in the CT scan ( d, e). The ruptured disc C2/C3 was removed and replaced with a tricortical iliac crest bone graft. Subsequently, the cervical spine was stabilized with an anterior plate. The lateral views demonstrate the radiographs/CT scan taken during the operation ( f), postoperatively (g, h), and after 9months( i). Note that the fractures of the arc/pedicles healed after 9 months. 826 Section Fractures Epidemiology Themostcommonlyinjured vertebrae are C2, C6, and C7 Cervical spine injuries account for one-third of all spinal injuries Cervical spine injuries account for about one-third of all spinal injuries. Gold- berg et al. [89] prospectively studied 34069 patients with blunt trauma undergo- ing cervical spine radiographs at 21 institutions to accurately assess the preva- lence, spectrum, and distribution of cervical spine injury after blunt trauma. Of these patients, 818 (2.4%) had a total of 1496 distinct cervical spine injuries. The second cervical vertebra was the most common (24.0%) level of injury, one-third of which were odontoid fractures. In the subaxial spine, C6 and C7 were the most frequently affected levels (40%). The most frequent fracture site was the verte- bral body. Nearly two-thirds of all injuries (71%) were considered clinically sig- nificant. A neurological injury occurs in about 15% of spine trauma patients In order to evaluate the true incidence of spinal column and cord injury, Hu et al. [108] used the database of the Manitoba Health Services Insurance Plan (1981–1984) to identify all patients who had spinal injuries. The annual inci- dence rate of all spinal fractures was 64 per 100000. A total of 2063 patients were identified, 944 of whom were admitted to hospital. There were two incidence peaks, one occurring in young men and the other in elderly women. Of the hospi- talized patients, 182 had cervical injury, 286 had thoracic fracture, and 403 had injury in the lumbosacral spine. Associated injuries occurred in 38% of hospital- ized patients. Neurological injury occurred in 122 patients (13%). A low GCS indicates a high risk for a concomitant cervical injury In a retrospective review of 14577 blunt trauma victims in a tertiary referral center in Baltimore, 614 (4.2%) had cervical spine injuries. In a series of 14755 trauma cases in Los Angeles [64], 292 (2%) patients had cervical spinal injuries. Of these, 86% had fractures, 10% had subluxations and 4% had an isolated spi- nal cord injury without fracture or obvious ligamentous damage. Importantly, the incidence of cervical injuries increased in patients with a low Glasgow Coma Scale (GCS) score, indicating that patients with a relevant head injury are at risk of having concomitant cervical injuries. The combination of head injury and cer- vical spine injury represents a difficult diagnostic problem due to the lack of con- sciousness in these patients. In a consecutive study of 447 patients with head injuries [106], 24 (5.4%) patients suffered a cervical spine injury. Of these, 14 (58%) sustained spinal cord injuries. Furthermore, patients with a GCS of less than 9 have an almost 3 times higher risk of sustaining a cervical injury [64]. Sim- ilarly, patients involved in motor vehicle accidents – either as passengers or as pedestrians – are at high risk of sustaining cervical spine injuries. Alker et al. examined 312 victims from traffic accidents and found cervical spine injuries in 24.4%. Of these, 93% affected the upper cervical spine [15]. A specific entity of cervical injuries (sprains and strains)isrelatedtorear-end or side impact motor vehicle collisions [184], but can also occur during diving or other mishaps [201]. In the United States, neck strain/sprain is the most com- mon type of injury to motor vehicle occupants treated in US hospital emergency departments, with an annual incidence of 328 per 100000 inhabitants [158]. The impact during the motor vehicle collision may result in bony or soft-tissue inju- ries (whiplash injury), which in turn may lead to a variety of clinical symptoms (whiplash-associated disorders, WAD) [184]. Injury mechanism and symptoms after rear-end collision must be differentiated The unfortunate term “whiplash” was introduced into the literature by Crowe in 1928 [55]. This expression was intended to be a description of a motion, but it has been accepted by physicians, patients and attorneys as the name of a disease. This misunderstanding has led to its misapplication by many physicians and oth- ers over the years [55]. The incidence of WAD is substantially increasing Reliable epidemiological data on this type of injury is hampered by the fact that definitions are largely variable [181]. Depending on the definition of whip- Cervical Spine Injuries Chapter 30 827 . presence of a back mass. The vast majority of spinal cord malformations re- sult in a tethering of the spinal cord. We differenti- ate primary tethered cord as a result of spinal mal- formations and. (might produce spinal hypoxia) Valsalva-type maneuvers to prevent spinal venous congestion In Utero Treatment Fetalsurgeryforspinal dysraphism is feasible After a diagnosis of fetal spinal dysraphism,. Michael T, Hoffmann KT, Bennedorf G, Brock M (2004) Surgical aspects and outcome of delayed tethered cord release. Zentralbl Neurochir 65:161–167 9. Hoffman HJ (1996) Indications and treatment of the

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