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Early skeletal and dental changes following mandibular advancement and rigid internal fixation
CURRENT LITERATURE
Naloxone, Fentanyl, and Diazepam Modify Plasma BetaEndorphin Levels During Surgery. Hargreaves KM, Dionne RA, Mueller GP, et al. Clin Pharmacol Ther 40: 165, 1986 The oral surgery model was utilized to examine perioperative levels of immunoreactive beta-endorphin (iBEND) in 48 patients receiving either naloxone, fentanyl, diazepam, or saline solution (placebo). Baseline determinations of iB-END and norepinephrine were measured one week prior to surgery; perceived levels of pain and anxiety were obtained utilizing the Spielberger state-trait anxiety index (STAI) and visual analog scale (VAS) for pain and anxiety. Extraction of impacted third molars was performed, at whcih time patients randomly received 10 mg naloxone, 0.1 mg fentanyl, 0.3 diazepam, or saline placebo. New blood samples were drawn one to three hours postoperatively, and the VASISTAI were again employed to measure intraoperative pain and anxiety. Results indicate that iB-END and pain were elevated significantly in the naloxone group; the diazepam and fentanyl groups exhibited decreased levels of both. All groups, except for those receiving diazepam, displayed increased postoperative levels of norepinephrine, circulating iBEND, and discomfort. The findings of this study indicate that the opioid antagonists stimulate the release of iBEND from the pituitary, and the agonist group inhibit this process; the proposed mechanism involves an alteration in the perception of pain.-A. DARLOW Reprint requests to Dr. Hargreaves: NAB, NIDR, NIH; Building 10, Room lA-09, 9000 Rockville Pike, Bethesda, MD 20892. Extended Experimental and Preliminary Surgical Findings with Autologous Fibrin Tissue Adhesive Made From the Patient’s Own Blood. Siedentop KH, Harris DM, Ham K, et al. Laryngoscope 96:1062, 1986 The use of fibrin tissue adhesive in the United States has been limited due to the lack of an available commercial product. Commercial products currently used in Europe are prepared from donors and carry the potential risk of disease transmission. The authors present a method of autologous production of fibrin and its use of tissue adhesive in the middle ear surgery. A comparison of bonding strength with a commercial glue was also done; bond strength of the autologous adhesive was comparable to that of the commercial glue. The advantages of the fibrin adhesive over other methods include biodegradability, better stabilization of grafts, and better use of hemostasis.-W. R. WHITLOW The Skeletal Anatomy of Mandibulofacial Dysostosis (Treacher Collins Syndrome). Marsh J, Celin S, Vannier M, et al. Plast Reconstr Surg 78:460, 1986 The development of three-dimensional surface reformation CT scan data allows images to be studied and analyzed for anatomical abnormalities. With the use of CT osseous surface reconstruction, the authors were able to isolate and examine dysmorphology of the temporal, zygoma, maxilla, mandible, orbital bases, and pterygoid plates and pterygoid muscles in 14 patients with mandibulofacial dysostosis. Previous reports used conventional skull radiographs; cephalometry, and pleuridirectional polytomography with poor visualization of the facial
199
bones and overlapping shadows. The authors found that in addition to either aplasia or severe hypoplasia of the zygomatic process of the temporal bones and deformity of the orbital rim, zygoma, mandible, medial pterygoid plates and hypoplasia of the medial pterygoid muscles, there was significant asymmetry of the osseous deformities in all of the patients studied. Furthermore, hypoplasia of the medial and lateral pterygoid muscles was noted in nearly all patients. The new radiographic technic may allow further study of the development of skeletal and soft tissue structures in the craniofacial region and provide a more quantitative analysis of the images of size and shape of the individual anatomical parts.-B. W. BURGER Reprint requests to Dr. Marsh: Cleft Palate and Craniofacial Deformities Institute, Children’s Hospital, 400 S. Kingshighway, St. Louis. MO 63110.
Lorazepam (Ativan) and Fetanyl (Sublimaze) for Outpatient Office Plastic Surgery Anesthesia. Colon GA, Gubert N. Plast Reconstr Surg 78:486, 1986 The authors present a technique for outpatient surgical anesthesia and the results of its use on 814 patients. Ativan was used in a dose of 0.04 mg/kg given IV 20 minutes before the procedure, and then fentanyl 25 pg was given at the start of the procedure. Fentanyl (25 Fg) was readministered every 30 minutes. All patients were observed the evening of surgery and the following morning and questioned about side effects and recall. Five categories of patient reactions were evaluated: intraoperative pain, recall of surgery, occurrence of dreams, emergence reactions, and nausea. Over 97% of the 814 patients were free of side effects.-S. DOOT Reprint requests to Dr. Colon: 4204 Teuton Street, Metaire. LA 70006.
Early Skeletal and Dental Changes Following Mandibular Advancement and Rigid Internal Fixation. Thomas PM, Tucker MR, Prewitt JR, et al. Adult Orthod Orthognath Surg 1:171, 1986 The study examined early dental and skeletal changes following mandibular advancement with bilateral sagittal split osteotomies, comparing lag screw stabilization with conventional wire osteosynthesis. Bilateral osteotomies were performed on 34 patients, with 14 patients receiving rigid lag screw fixation and the remainder of patients receiving conventional wiring. The typical patient in the “rigid group” had maxillomandibular fixation for three to seven days and in the “wire group” for six weeks. Both groups were allowed to function into an occlusal splint guided by training elastics after the release of fixation. Multiple parameters were studied on cephalometric radiographs taken preoperatively, 24 hours postoperatively and after the removal of the occlusal splint. The wire group experienced a mean maxillary incisor retroinclination of 2.4” and mandibular incisor proclination of 4.9”. These same parameters in the rigid group were less than half of those seen in the wire group. When compared to the rigid group, a statistically greater posterior and inferior movement at B point, superior movement of gonion and increased steepness of the mandibular plane was found in the wire group. These changes result from a slight counterclockwise rotation of the proximal segment
200 and clockwise rotation of the distal segment. Additionally, a slight net gain in B point advancement was observed in the rigid group during the six-week postoperative period. The authors stressed the techniquelsensitivity of the rigid system and the lack of long-term data on potential complications encountered with this technique.-S. C. BRYAN
The Clinical Examination: Is It More Important than Cephalometric Analysis in Surgical Orthodontics? Wallen T, Bloomquist D. Adult Orthod Orthognath Surg 1:179, 1986 Cephalometric analysis is used by many clinicians as a major treatment planning tool without realizing the inherent flaws that the individual analysis may have. This report stresses the inadequacies of this approach by reviewing cases where cephalometric analysis played a minimal role in treatment decisions. Most cephalometric analyses use averages to describe a trait in a relatively limited population. This does not allow for the variations that occur within the individual reference points or angles, and therefore, the large variations that exist between these reference points or angles in individual “normal” people are concealed. The often small dimensional differences between the cephalometric averages and the patient’s measurements may have little biologic or clinical importance. All data obtained from cephalometric analysis are static, describing dental and facial characteristics in one occlusal relationship at one given point in time. Three cases were presented to exemplify the problems in diagnosis and treatment planning that are difficult or impossible to recognize from a cephalometric tracing. Specific problems include the lack of appreciation of transverse facial dimensions and alar base support. The true relationship between the upper lip and maxillary incisors is often poorly reflected on the cephalometric radiograph. Difficulty is also encountered when making treatment planning decisions when skeletal dysplasias are mild. The emphasis on cephalometric analysis and prediction tracings may be secondary to the ease with which this information can be presented and discussed. The reliance on lateral cephalometric analyses may lead to surgical treatment planning primarily done in two dimensions. The need for thorough clinical evaluation of the patient and the knowledge of limitations of current cephalometric diagnostic and treatment planning modalities is stressed.-S. C. BRYAN
CURRENT
LITERATURE
Neuropsychological Changes in a Young, Healthy Population After Controlled Hypotensive Anesthesia. Townes BD, Dikmen SS, Bledsoe SW, et al. Anesth Analg 65:955, 1986 Intentional hypotension is a common adjunct to anesthesia to diminish bleeding, reduce the requirement for blood replacement, and to improve the quality of the surgical field. A study was undertaken to evaluate the effects of anesthesia on memory and cognition and to determine the differential effects of hypotensive and normotensive halothane anesthesia on neuropsychologic testing; to determine whether the intraoperative EEG correlates with changes in postoperative neuropsychologic functioning; and to ascertain the permanency of such effects. Hypotensive anesthesia (mean arterial pressure of 58.6 mm Hg) was achieved in 17 patients undergoing maxillary and mandibular osteotomies with halothane (1.27%) and IV trimethaphan camsylate. The control group consisted of 27 patients undergoing sagittal split ramus osteotomies with halothane anesthesia (1.26%) and mean arterial pressure maintained at 83.2 mm Hg. Eight channel EEGs were performed on all subjects intraoperatively every 2.5 minutes. Because of the power liability, the EEG was insensitive to subtle changes in cerebral function. There were no significant differences in EEG power between the prehypotensive and hypotensive anesthetic periods. Preoperative neuropsychologic test performance was similar in both the hypotensive and normotensive groups, and immediate postoperative neuropsychologic test performance was similar in both groups. There was a generalized effect of anesthesia on learning and memory in both groups. During the immediate postanesthetic period, learning took place more slowly and information was not retained as effectively. By six months, both groups had returned to baseline neuropsychologic test performance. In summary, hypotensive anesthesia was not associated with any greater impairment in neuropsychologic test performance than in normotensive controls. Additionally, no long-term (six months) impairment in neuropsychologic test performance was detected in either group. Results of postoperative neuropsychologic testing reflected impairment in memory and learning in both groups, presumably secondary to halothane. The authors suggest further studies performed to compare the effects of different anesthetic agents on postsurgical cognitive functioning.-S. .I. MCKENNA Reprint requests to Dr. Townes: Mail Stop AA-41, University of Washington, Seattle, WA 98195.
Naloxone, Fentanyl, and Diazepam Modify Plasma BetaEndorphin Levels During Surgery. Hargreaves KM, Dionne RA, Mueller GP, et al. Clin Pharmacol Ther 40: 165, 1986 The oral surgery model was utilized to examine perioperative levels of immunoreactive beta-endorphin (iBEND) in 48 patients receiving either naloxone, fentanyl, diazepam, or saline solution (placebo). Baseline determinations of iB-END and norepinephrine were measured one week prior to surgery; perceived levels of pain and anxiety were obtained utilizing the Spielberger state-trait anxiety index (STAI) and visual analog scale (VAS) for pain and anxiety. Extraction of impacted third molars was performed, at whcih time patients randomly received 10 mg naloxone, 0.1 mg fentanyl, 0.3 diazepam, or saline placebo. New blood samples were drawn one to three hours postoperatively, and the VASISTAI were again employed to measure intraoperative pain and anxiety. Results indicate that iB-END and pain were elevated significantly in the naloxone group; the diazepam and fentanyl groups exhibited decreased levels of both. All groups, except for those receiving diazepam, displayed increased postoperative levels of norepinephrine, circulating iBEND, and discomfort. The findings of this study indicate that the opioid antagonists stimulate the release of iBEND from the pituitary, and the agonist group inhibit this process; the proposed mechanism involves an alteration in the perception of pain.-A. DARLOW Reprint requests to Dr. Hargreaves: NAB, NIDR, NIH; Building 10, Room lA-09, 9000 Rockville Pike, Bethesda, MD 20892. Extended Experimental and Preliminary Surgical Findings with Autologous Fibrin Tissue Adhesive Made From the Patient’s Own Blood. Siedentop KH, Harris DM, Ham K, et al. Laryngoscope 96:1062, 1986 The use of fibrin tissue adhesive in the United States has been limited due to the lack of an available commercial product. Commercial products currently used in Europe are prepared from donors and carry the potential risk of disease transmission. The authors present a method of autologous production of fibrin and its use of tissue adhesive in the middle ear surgery. A comparison of bonding strength with a commercial glue was also done; bond strength of the autologous adhesive was comparable to that of the commercial glue. The advantages of the fibrin adhesive over other methods include biodegradability, better stabilization of grafts, and better use of hemostasis.-W. R. WHITLOW The Skeletal Anatomy of Mandibulofacial Dysostosis (Treacher Collins Syndrome). Marsh J, Celin S, Vannier M, et al. Plast Reconstr Surg 78:460, 1986 The development of three-dimensional surface reformation CT scan data allows images to be studied and analyzed for anatomical abnormalities. With the use of CT osseous surface reconstruction, the authors were able to isolate and examine dysmorphology of the temporal, zygoma, maxilla, mandible, orbital bases, and pterygoid plates and pterygoid muscles in 14 patients with mandibulofacial dysostosis. Previous reports used conventional skull radiographs; cephalometry, and pleuridirectional polytomography with poor visualization of the facial
199
bones and overlapping shadows. The authors found that in addition to either aplasia or severe hypoplasia of the zygomatic process of the temporal bones and deformity of the orbital rim, zygoma, mandible, medial pterygoid plates and hypoplasia of the medial pterygoid muscles, there was significant asymmetry of the osseous deformities in all of the patients studied. Furthermore, hypoplasia of the medial and lateral pterygoid muscles was noted in nearly all patients. The new radiographic technic may allow further study of the development of skeletal and soft tissue structures in the craniofacial region and provide a more quantitative analysis of the images of size and shape of the individual anatomical parts.-B. W. BURGER Reprint requests to Dr. Marsh: Cleft Palate and Craniofacial Deformities Institute, Children’s Hospital, 400 S. Kingshighway, St. Louis. MO 63110.
Lorazepam (Ativan) and Fetanyl (Sublimaze) for Outpatient Office Plastic Surgery Anesthesia. Colon GA, Gubert N. Plast Reconstr Surg 78:486, 1986 The authors present a technique for outpatient surgical anesthesia and the results of its use on 814 patients. Ativan was used in a dose of 0.04 mg/kg given IV 20 minutes before the procedure, and then fentanyl 25 pg was given at the start of the procedure. Fentanyl (25 Fg) was readministered every 30 minutes. All patients were observed the evening of surgery and the following morning and questioned about side effects and recall. Five categories of patient reactions were evaluated: intraoperative pain, recall of surgery, occurrence of dreams, emergence reactions, and nausea. Over 97% of the 814 patients were free of side effects.-S. DOOT Reprint requests to Dr. Colon: 4204 Teuton Street, Metaire. LA 70006.
Early Skeletal and Dental Changes Following Mandibular Advancement and Rigid Internal Fixation. Thomas PM, Tucker MR, Prewitt JR, et al. Adult Orthod Orthognath Surg 1:171, 1986 The study examined early dental and skeletal changes following mandibular advancement with bilateral sagittal split osteotomies, comparing lag screw stabilization with conventional wire osteosynthesis. Bilateral osteotomies were performed on 34 patients, with 14 patients receiving rigid lag screw fixation and the remainder of patients receiving conventional wiring. The typical patient in the “rigid group” had maxillomandibular fixation for three to seven days and in the “wire group” for six weeks. Both groups were allowed to function into an occlusal splint guided by training elastics after the release of fixation. Multiple parameters were studied on cephalometric radiographs taken preoperatively, 24 hours postoperatively and after the removal of the occlusal splint. The wire group experienced a mean maxillary incisor retroinclination of 2.4” and mandibular incisor proclination of 4.9”. These same parameters in the rigid group were less than half of those seen in the wire group. When compared to the rigid group, a statistically greater posterior and inferior movement at B point, superior movement of gonion and increased steepness of the mandibular plane was found in the wire group. These changes result from a slight counterclockwise rotation of the proximal segment
200 and clockwise rotation of the distal segment. Additionally, a slight net gain in B point advancement was observed in the rigid group during the six-week postoperative period. The authors stressed the techniquelsensitivity of the rigid system and the lack of long-term data on potential complications encountered with this technique.-S. C. BRYAN
The Clinical Examination: Is It More Important than Cephalometric Analysis in Surgical Orthodontics? Wallen T, Bloomquist D. Adult Orthod Orthognath Surg 1:179, 1986 Cephalometric analysis is used by many clinicians as a major treatment planning tool without realizing the inherent flaws that the individual analysis may have. This report stresses the inadequacies of this approach by reviewing cases where cephalometric analysis played a minimal role in treatment decisions. Most cephalometric analyses use averages to describe a trait in a relatively limited population. This does not allow for the variations that occur within the individual reference points or angles, and therefore, the large variations that exist between these reference points or angles in individual “normal” people are concealed. The often small dimensional differences between the cephalometric averages and the patient’s measurements may have little biologic or clinical importance. All data obtained from cephalometric analysis are static, describing dental and facial characteristics in one occlusal relationship at one given point in time. Three cases were presented to exemplify the problems in diagnosis and treatment planning that are difficult or impossible to recognize from a cephalometric tracing. Specific problems include the lack of appreciation of transverse facial dimensions and alar base support. The true relationship between the upper lip and maxillary incisors is often poorly reflected on the cephalometric radiograph. Difficulty is also encountered when making treatment planning decisions when skeletal dysplasias are mild. The emphasis on cephalometric analysis and prediction tracings may be secondary to the ease with which this information can be presented and discussed. The reliance on lateral cephalometric analyses may lead to surgical treatment planning primarily done in two dimensions. The need for thorough clinical evaluation of the patient and the knowledge of limitations of current cephalometric diagnostic and treatment planning modalities is stressed.-S. C. BRYAN
CURRENT
LITERATURE
Neuropsychological Changes in a Young, Healthy Population After Controlled Hypotensive Anesthesia. Townes BD, Dikmen SS, Bledsoe SW, et al. Anesth Analg 65:955, 1986 Intentional hypotension is a common adjunct to anesthesia to diminish bleeding, reduce the requirement for blood replacement, and to improve the quality of the surgical field. A study was undertaken to evaluate the effects of anesthesia on memory and cognition and to determine the differential effects of hypotensive and normotensive halothane anesthesia on neuropsychologic testing; to determine whether the intraoperative EEG correlates with changes in postoperative neuropsychologic functioning; and to ascertain the permanency of such effects. Hypotensive anesthesia (mean arterial pressure of 58.6 mm Hg) was achieved in 17 patients undergoing maxillary and mandibular osteotomies with halothane (1.27%) and IV trimethaphan camsylate. The control group consisted of 27 patients undergoing sagittal split ramus osteotomies with halothane anesthesia (1.26%) and mean arterial pressure maintained at 83.2 mm Hg. Eight channel EEGs were performed on all subjects intraoperatively every 2.5 minutes. Because of the power liability, the EEG was insensitive to subtle changes in cerebral function. There were no significant differences in EEG power between the prehypotensive and hypotensive anesthetic periods. Preoperative neuropsychologic test performance was similar in both the hypotensive and normotensive groups, and immediate postoperative neuropsychologic test performance was similar in both groups. There was a generalized effect of anesthesia on learning and memory in both groups. During the immediate postanesthetic period, learning took place more slowly and information was not retained as effectively. By six months, both groups had returned to baseline neuropsychologic test performance. In summary, hypotensive anesthesia was not associated with any greater impairment in neuropsychologic test performance than in normotensive controls. Additionally, no long-term (six months) impairment in neuropsychologic test performance was detected in either group. Results of postoperative neuropsychologic testing reflected impairment in memory and learning in both groups, presumably secondary to halothane. The authors suggest further studies performed to compare the effects of different anesthetic agents on postsurgical cognitive functioning.-S. .I. MCKENNA Reprint requests to Dr. Townes: Mail Stop AA-41, University of Washington, Seattle, WA 98195.