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Chondroid bone, secondary cartilage and metaphasia
CURRENT
537
LITERATURE
authors propose the use of an osteosynthesis plate in the fronto-zygomatic region to restore cheek prominence in combination with a sinus balloon for support. Their technique employed fixation with a malleable osteosynthesis plate in the fronto-zygomatic region via standard brow incision, utilizing a Palfer-Sollier lever through an intraoral trans-sinus approach to elevate and manually realign the fractured zygoma. The subsequent remodeling and consolidation of the remaining reduced fractured sites occurred spontaneously through favorable action of the adjacent soft tissue and muscle pull along the zygomaticomasseteric-mandibular axis. With this procedure, the risk to the blood supply of some cornminuted fragments may be obviated. The principle disadvantage of this technique is that it depends largely on tactile manipulation, and therefore visualization and precise alignment of the fracture segments is not possible.-SIMON BERGMAN Postconcussive hospital observation of alert patients in a primary trauma center. Fischer RP, Carlson J, Perry JF. J Trauma 21:920, 1981 The medical justification for many postconcussive hospital admissions (one fourth of all trauma admissions) is unsettled, as are the potential legal consequences of nonadmission. Three hundred thirty-three patients with Class I level of consciousness (alert, responsive to questions and complex commands, may be disoriented and/or confused) were admitted during a six-month period; of those, 79% had sustained loss of consciousness, 81% were admitted solely for neurologic observation, and 13% had skull fractures. Patients admitted with localized neurologic findings were most likely to have skull fractures. Of the confirmed skull fractures, 30% occurred in patients without “high yield” criteria for skull radiographs. No deaths and no neurologic sequelae occurred among the patients without skull fractures. In contrast, among the 43 patients with skull fractures, one patient died of neurologic injuries, major neurologic sequelae developed in seven patients, and eight patients required neurosurgical intervention. In this series, only the presence of a skull fracture was of grave prognostic significance among patients with Class I level of consciousness following closed head injuries. No benefit was derived from the precautionary admission of patients with Class I level of consciousness following closed head injuries who had not sustained skull fractures. Oral glycerol for the treatment of traumatic intracranial hypertension. Wald S, McLaurin RL. J Neurosurg 56:323, 1982 Intracranial pressure is a potentially fatal complication of many conditions of the central nervous system. Both morbidity and mortality have been reduced with aggressive management of cerebral edema. Various drugs and drug regimens have been studied since the advent of intracranial pressure monitoring devices, with hyperosmolar agents as primary therapeutic modalities; but profound hyperosmolarity and associated systemic dehydration, as well as electrolyte imbalances, are common side effects of these drugs. This clinical investigation examined the effectiveness of oral glycerol in decreasing intracranial pressure, particularly in cases of craniocerebral trauma. Glycerol,
which is a water-soluble alcohol, is metabolized in the liver and has decreased dehydrating capacity. Fifteen patients were studied, 12 following craniocerebral trauma and three with intracerebral or intraventricular hemorrhage. In all patients, intracranial pressure monitors were placed and a glycerol treatment protocol was instituted of 0.5 to 1.0 gram every three to four hours as indicated by intracranial pressure and duration of drug effect. Specific individual dosages ranged from 4 to 70 grams with an average of 54 grams. A reduction of intracranial pressure by 50% or more was found in over 70% of the trials and was not dependent on the initial level of intracranial pressure at the time of administration. Only minor changes in serum electrolytes, glucose, and urea nitrogen were noted. Serum osmolarity increased from a baseline at 305 mOsm/l to 355 mOsm/l after ten days of therapy. Glycerol is a safe and effective adjunct to standard therapeutic protocols for post-traumatic intracranial hypertension.-DON NUNN Pulmonary atelectasis after anaesthesia: Pathophysiology and management. Rigg JRA. Can Anaesth Sot J 28:305. 1981 The pathophysiologic basis of pulmonary atelectasis is reviewed, and risk factors that enhance lung collapse are discussed. Management strategies for reducing or eliminating risk factors and preventing collapse are discussed. and the rational bases of these strategies are identified. Instability of lung alveoli is a consequence of surface tension and regional differences in alveolar size. The inherent tendency of alveoli to collapse is enhanced by the following risk factors: low lung volume: high closing volume; oxyen therapy; a rapid shallow ventilatory pattern: chronic lung disease: smoking; obesity: postoperative pain following abdominal or thoracic surgery; narcoticinduced ventilatory depression; and neurologic, neuromuscular, muscular, and musculoskeletal diseases associated with mechanical impairment of respiratory function. The primary goal of perioperative respiratory management is prevention of atelectasis. Appropriate management strategies include physiotherapy and delay of elective surgery if substantial improvement in respiratory status can be achieved by specific treatments such as antibiotics, bronchodilators, steroids, and reduction of tobacco use and caloric intake. In selected cases, elective postoperative controlled ventilation may be indicated. New Book Annotations Chondroid Bone, Secondary Cartilage and Metaplasia. Beresford WA. Baltimore, Urban & Schwarzenberg, 1980, 454 pp. illustrated, $42.50 The perplexing nature of three peculiar skeletal phenomena is extensively discussed in this book. The histogenetic, pathologic, and biochemical significance of chondroid bone is analyzed; the concept of secondary cartilage is reviewed: and the processes underlying the transformation of differentiated cells are described. The basic information in these areas is then applied to the understanding of craniofacial development, formation of fracture callus, transplantation of skeletal tissues, and bone and cartilage neoplasia, among other subjects.
537
LITERATURE
authors propose the use of an osteosynthesis plate in the fronto-zygomatic region to restore cheek prominence in combination with a sinus balloon for support. Their technique employed fixation with a malleable osteosynthesis plate in the fronto-zygomatic region via standard brow incision, utilizing a Palfer-Sollier lever through an intraoral trans-sinus approach to elevate and manually realign the fractured zygoma. The subsequent remodeling and consolidation of the remaining reduced fractured sites occurred spontaneously through favorable action of the adjacent soft tissue and muscle pull along the zygomaticomasseteric-mandibular axis. With this procedure, the risk to the blood supply of some cornminuted fragments may be obviated. The principle disadvantage of this technique is that it depends largely on tactile manipulation, and therefore visualization and precise alignment of the fracture segments is not possible.-SIMON BERGMAN Postconcussive hospital observation of alert patients in a primary trauma center. Fischer RP, Carlson J, Perry JF. J Trauma 21:920, 1981 The medical justification for many postconcussive hospital admissions (one fourth of all trauma admissions) is unsettled, as are the potential legal consequences of nonadmission. Three hundred thirty-three patients with Class I level of consciousness (alert, responsive to questions and complex commands, may be disoriented and/or confused) were admitted during a six-month period; of those, 79% had sustained loss of consciousness, 81% were admitted solely for neurologic observation, and 13% had skull fractures. Patients admitted with localized neurologic findings were most likely to have skull fractures. Of the confirmed skull fractures, 30% occurred in patients without “high yield” criteria for skull radiographs. No deaths and no neurologic sequelae occurred among the patients without skull fractures. In contrast, among the 43 patients with skull fractures, one patient died of neurologic injuries, major neurologic sequelae developed in seven patients, and eight patients required neurosurgical intervention. In this series, only the presence of a skull fracture was of grave prognostic significance among patients with Class I level of consciousness following closed head injuries. No benefit was derived from the precautionary admission of patients with Class I level of consciousness following closed head injuries who had not sustained skull fractures. Oral glycerol for the treatment of traumatic intracranial hypertension. Wald S, McLaurin RL. J Neurosurg 56:323, 1982 Intracranial pressure is a potentially fatal complication of many conditions of the central nervous system. Both morbidity and mortality have been reduced with aggressive management of cerebral edema. Various drugs and drug regimens have been studied since the advent of intracranial pressure monitoring devices, with hyperosmolar agents as primary therapeutic modalities; but profound hyperosmolarity and associated systemic dehydration, as well as electrolyte imbalances, are common side effects of these drugs. This clinical investigation examined the effectiveness of oral glycerol in decreasing intracranial pressure, particularly in cases of craniocerebral trauma. Glycerol,
which is a water-soluble alcohol, is metabolized in the liver and has decreased dehydrating capacity. Fifteen patients were studied, 12 following craniocerebral trauma and three with intracerebral or intraventricular hemorrhage. In all patients, intracranial pressure monitors were placed and a glycerol treatment protocol was instituted of 0.5 to 1.0 gram every three to four hours as indicated by intracranial pressure and duration of drug effect. Specific individual dosages ranged from 4 to 70 grams with an average of 54 grams. A reduction of intracranial pressure by 50% or more was found in over 70% of the trials and was not dependent on the initial level of intracranial pressure at the time of administration. Only minor changes in serum electrolytes, glucose, and urea nitrogen were noted. Serum osmolarity increased from a baseline at 305 mOsm/l to 355 mOsm/l after ten days of therapy. Glycerol is a safe and effective adjunct to standard therapeutic protocols for post-traumatic intracranial hypertension.-DON NUNN Pulmonary atelectasis after anaesthesia: Pathophysiology and management. Rigg JRA. Can Anaesth Sot J 28:305. 1981 The pathophysiologic basis of pulmonary atelectasis is reviewed, and risk factors that enhance lung collapse are discussed. Management strategies for reducing or eliminating risk factors and preventing collapse are discussed. and the rational bases of these strategies are identified. Instability of lung alveoli is a consequence of surface tension and regional differences in alveolar size. The inherent tendency of alveoli to collapse is enhanced by the following risk factors: low lung volume: high closing volume; oxyen therapy; a rapid shallow ventilatory pattern: chronic lung disease: smoking; obesity: postoperative pain following abdominal or thoracic surgery; narcoticinduced ventilatory depression; and neurologic, neuromuscular, muscular, and musculoskeletal diseases associated with mechanical impairment of respiratory function. The primary goal of perioperative respiratory management is prevention of atelectasis. Appropriate management strategies include physiotherapy and delay of elective surgery if substantial improvement in respiratory status can be achieved by specific treatments such as antibiotics, bronchodilators, steroids, and reduction of tobacco use and caloric intake. In selected cases, elective postoperative controlled ventilation may be indicated. New Book Annotations Chondroid Bone, Secondary Cartilage and Metaplasia. Beresford WA. Baltimore, Urban & Schwarzenberg, 1980, 454 pp. illustrated, $42.50 The perplexing nature of three peculiar skeletal phenomena is extensively discussed in this book. The histogenetic, pathologic, and biochemical significance of chondroid bone is analyzed; the concept of secondary cartilage is reviewed: and the processes underlying the transformation of differentiated cells are described. The basic information in these areas is then applied to the understanding of craniofacial development, formation of fracture callus, transplantation of skeletal tissues, and bone and cartilage neoplasia, among other subjects.