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1.
Facial Plast Surg Clin North Am ; 32(2): 315-325, 2024 May.
Article in English | MEDLINE | ID: mdl-38575289

ABSTRACT

Soft tissue injuries to the midface (and nose) are common causes for seeking trauma care. As trauma patients, observing advanced trauma life support protocols is warranted given the risk of concomitant injuries. Here, options for optimizing tissue preservation, microvascular replantation, non-microvascular tissue replacement, and wound stabilization are discussed. Included in this discussion are data-driven predictors for successful replantation as well as technique descriptions with anatomic references to guide surgeons in choosing optimal donor vessels. In both partial and complete avulsion injuries, venous congestion is common. Several postoperative wound care protocols to maximize tissue perfusion and long-term viability are discussed.


Subject(s)
Amputation, Traumatic , Soft Tissue Injuries , Humans , Amputation, Traumatic/surgery , Microsurgery/methods , Replantation/methods , Soft Tissue Injuries/surgery , Nose/surgery , Nose/injuries
2.
Article in English | MEDLINE | ID: mdl-37948552

ABSTRACT

Background: Facial reanimation flaps often add bulk and produce single-vector smiles, and multivector flaps frequently require challenging intramuscular dissection. Objective: To evaluate the effectiveness of sterno-omohyoid flap (SOHF) transfer for dual-vector smile reanimation by measuring upper dental show and oral commissure movement. Methods: SOHF transfers from 2017 to 2020 were retrospectively evaluated using eFACE and Emotrics software. Results: Four patients with flaccid and one with nonflaccid facial paralysis were identified (four females and one male, median age: 39 years (range: 38-65); two acoustic neuromas, two congenital, one temporal bone fracture). Median follow-up was 20 months (range: 14-26). All flaps received masseteric nerves and two had additional cross-face grafts. Four developed contraction [median time to contraction: 5.5 months (range: 3-10)]. Mean oral commissure excursion and dental exposure improvements were 7.6 ± 4.0 mm (p = 0.03) and 2.9 ± 1.8 mm (p = 0.05), respectively. Dynamic, smile, and midface-smile eFACE improvements were 20.3 ± 6.8 (p = 0.007), 25.5 ± 14.5 (p = 0.03), and 50.5 ± 12.0 mm (p = 0.004) points, respectively. Mean SOHF mass was 14 ± 1.7 g. Conclusion: The SOHF is a small flap that provides dual-vector smile reanimation in flaccid and nonflaccid facial paralysis.

3.
Otolaryngol Clin North Am ; 56(4): 653-670, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37246030

ABSTRACT

The premises of mandibular reconstruction are the restoration of occlusion and mandibular contour for the purpose of preserving the facial identity, oral airway, and effective speech and mastication. Establishing functional occlusion is the primary tenant in all mandibular reconstruction. In cases of segmental defects, particularly in dentate regions of the mandible, there has been a paradigm shift over the past two decades in how surgeons are approaching the restoration of load-bearing mandibular continuity with capacity for dental implantation. Here we discuss considerations for deciding the most effective method of reconstruction in segmental defects.


Subject(s)
Mandibular Neoplasms , Mandibular Reconstruction , Humans , Mandibular Neoplasms/surgery , Bone Transplantation , Mandible/surgery , Face
4.
Article in English | MEDLINE | ID: mdl-32407138

ABSTRACT

Importance: Orbital floor fracture repair is complex and postoperative complications are common. A variety of applicable surgical techniques and technologies are available to surgeons, so data about which of these may decrease postoperative complication rates can help better guide clinical decision making. Objectives: To characterize the patient demographics and surgical techniques utilized in orbital floor fracture repairs at San Antonio Military Medical Center and their relationship with rates of postoperative complications. Design, Setting, and Participants: Retrospective chart review of patients who underwent orbital floor fracture repairs from March 2014 to March 2019 with a mean follow-up time of 1.86 months at a tertiary care academic military hospital and level 1 trauma center. Main Outcomes and Measures: Demographic data, indication for surgical repair, fracture severity, orbital floor approach, implant material, and use of intraoperative computed tomography (CT) scan were recorded. Chi-square analysis was performed to determine the relationship between these factors and postoperative diplopia, hypoglobus, enophthalmos, and infection. Results: A total of 124 procedures were performed during the study period: 71.8% of patients were male and 74% were civilian. Mean age was 39 years (range 19-81). Thirty-one patients were lost to follow-up. The most common approach was transconjunctival (83%), which was most frequently used exclusively (68.5%), but was also combined with cantholysis, transcaruncular, or transantral approach. Postoperative diplopia at follow-up was common (53.8%), resolved after an average of 36.3 days, and was significantly associated with surgical indication of entrapment or revision (p = 0.01) and nonutilization of intraoperative CT (p = 0.04). From 2014 to 2016, intraoperative CT was utilized in 21% of cases and revision rate was 10.5%. From 2017 to 2019, 50% of cases utilized intraoperative CT and revision rate was 2% (p = 0.15). Three cases were revisions performed for abnormal plate position noted on postoperative CT scan. Conclusions and Relevance: A statistically significant association was found between postoperative diplopia, surgical indication of entrapment or revision, and nonutilization of intraoperative CT. Revision rates decreased when use of intraoperative CT increased. Three revision cases may have been prevented by use of an intraoperative CT scan. Patients with entrapment should be counseled regarding the increased risk of postoperative diplopia.

5.
Ann Otol Rhinol Laryngol ; 129(2): 195-200, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31578078

ABSTRACT

BACKGROUND: Dynamic rehabilitation of longstanding facial palsy with damaged, atrophied, or absent facial muscles requires replacement of neural and muscular components. The ideal reconstruction would include a fast-twitch muscle that is small, a reliable donor vessel and nerve, and the potential to provide a natural, synchronous, dentate smile with minimal donor site morbidity. Many flaps have been successfully used historically, but none has produced ideal rehabilitation. OBJECTIVE: To evaluate the novel sterno-omohyoid, dual-vector flap in rehabilitation of chronic facial paralysis. RESULTS: We performed sterno-omohyoid free tissue transfer for smile reanimation in a 39-year-old male with a history of longstanding right facial palsy following resection of a skull base tumor several years previously. We transferred both muscles with the superior thyroid artery, middle thyroid vein, and ansa cervicalis. The patient developed a dynamic smile by 6 months postoperatively, and he had improved objective facial symmetry. CONCLUSION: Herein, we demonstrate the first use of the sterno-omohyoid flap for successful facial reanimation. Overall, it is a novel flap in facial reanimation with many advantages over traditional flaps, including the potential to produce a more synchronous, dynamic smile while adding minimal bulk to the face. Future series will better elucidate the potential of the sterno-omohyoid flap.


Subject(s)
Facial Paralysis/rehabilitation , Facial Paralysis/surgery , Free Tissue Flaps , Adult , Chronic Disease , Humans , Male , Neck Muscles/transplantation , Smiling
6.
JAMA Facial Plast Surg ; 21(6): 504-510, 2019 Dec 01.
Article in English | MEDLINE | ID: mdl-31465094

ABSTRACT

IMPORTANCE: Synkinesis is the involuntary movement of 1 area of the face accompanying volitional movement of another; it is commonly encountered in patients affected by facial palsy. Current treatments for synkinesis include biofeedback for muscular retraining and chemodenervation via the injection of botulinum toxin. Chemodenervation is effective in reducing unwanted muscle movement, but it requires a commitment to long-term maintenance injections and may lose effectiveness over time. A permanent solution for synkinesis remains elusive. OBJECTIVE: To evaluate masseteric-to-facial nerve transfer with selective neurectomy in rehabilitation of the synkinetic smile. DESIGN, SETTING, AND PARTICIPANTS: In this case series, 7 patients at a tertiary care teaching hospital underwent masseteric-to-facial nerve transfer with selective neurectomy for synkinesis between September 14, 2015, and April 19, 2018. The medical records of these patients were retrospectively reviewed and demographic characteristics, facial palsy causes, other interventions used, and changes in eFACE scores were identified. INTERVENTION: Masseteric-to-facial nerve transfer. MAIN OUTCOMES AND MEASURES: Changes in eFACE scores (calculated via numeric scoring of many sections of the face, including flaccidity, normal tone, and hypertonicity; higher scores indicate better function and lower scores indicate poorer function) and House-Brackmann Facial Nerve Grading System scores (range, 1-6; a score of 1 indicates normal facial function on the affected side, and a score of 6 indicates absence of any facial function [complete flaccid palsy] on the affected side). RESULTS: Among the 7 patients in the study (6 women and 1 man; median age, 49 years [range, 41-63 years]), there were no postoperative complications; patients were followed up for a mean of 12.8 months after surgery (range, 11.0-24.5 months). Patients experienced a significant improvement in mean (SD) eFACE scores in multiple domains, including smile (preoperative, 65.00 [8.64]; postoperative, 76.43 [7.79]; P = .01), dynamic function (preoperative, 62.57 [15.37]; and postoperative, 75.71 [8.48]; P = .03), synkinesis (preoperative, 52.70 [4.96]; and postoperative, 82.00 [6.93]; P < .001), midface and smile function (preoperative, 60.71 [13.52]; and postoperative, 78.86 [14.70]; P = .02), and lower face and neck function (preoperative, 51.14 [16.39]; and postoperative, 66.43 [20.82]; P = .046). Preoperative House-Brackmann Facial Nerve Grading System scores ranged from 3 to 4, and postoperative scores ranged from 2 to 3; this change was not significant. CONCLUSION AND RELEVANCE: This study describes the application of masseteric-to-facial nerve transfer with selective neurectomy for smile rehabilitation in patients with synkinesis, with statistically significant improvement in smile symmetry and lower facial synkinesis as measured with the eFACE tool. This technique may allow for long-term improvement of synkinesis and smile. This study is only preliminary, and a larger cohort will permit more accurate assessment of this therapeutic modality. LEVEL OF EVIDENCE: 4.


Subject(s)
Facial Nerve/surgery , Facial Paralysis/surgery , Masseter Muscle/innervation , Nerve Transfer/methods , Smiling , Synkinesis/surgery , Adult , Female , Humans , Male , Middle Aged , Retrospective Studies
7.
Facial Plast Surg Clin North Am ; 25(4): 513-535, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28941505

ABSTRACT

Orbital reconstruction is one of the most challenging tasks for surgeons who treat craniofacial trauma. Suboptimal outcomes carry a high level of morbidity, with functional, emotional, and aesthetic implications. However, advances in reconstruction techniques, including the use of orbital endoscopy, computer-guided navigation, and mirror image overlay techniques, have been shown to provide significant improvements in outcomes. This article provides practical advice for applying these techniques to orbital reconstruction following trauma.


Subject(s)
Orbit/surgery , Orbital Fractures/surgery , Plastic Surgery Procedures/trends , Endoscopy , Humans , Orbit/anatomy & histology , Orbit/diagnostic imaging , Orbital Fractures/diagnostic imaging , Photography , Preoperative Care , Surgery, Computer-Assisted
8.
Ann Otol Rhinol Laryngol ; 126(10): 688-692, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28831833

ABSTRACT

BACKGROUND: The employment of 2-octylcyanoacrylate adhesive (Dermabond) to assist graft placement in open septorhinoplasty has been increasingly used to stabilize cartilage grafts. Literature regarding this application has been mixed, with some showing the possibility of increased rates of inflammation, if not infection. We present an original comparative case series involving postoperative septal abscess formation adjacent to caudal strut grafting where both Dermabond and an absorbable polydioxanone (PDS) plate were used. OBJECTIVE: To report an original comparative case series of patients who developed a postoperative septal abscess following open septorhinoplasty in the context of Dermabond application to affix cartilage to a PDS plate to facilitate caudal septal strut grafting. DESIGN: Retrospective comparative series with relevant clinical photographs, culture studies, and surgical figures. SETTING: Tertiary medical treatment facility. RESULTS: Two patients underwent primary open septorhinoplasty with placement of an autologous caudal septal extension graft, which was stabilized using a PDS plate and secured into position using both Dermabond and PDS suture. Postoperatively, both patients presented a nasal septal abscess at an average of 8 weeks that required serial drainage and subsequent removal of the PDS plate in 1 of the patients. Cultures demonstrated mixed flora as well as Proteus mirabilis, previously unreported in the nasal septal abscess literature. In comparison to 8 patients who underwent reconstruction with PDS plate alone (without Dermabond application), this represents a relative risk of 15 ( P value = .053) for a septal abscess complication when Dermabond is employed . CONCLUSIONS: We present an original case series on our limited, though impactful experience with PDS plate reconstruction using Dermabond to facilitate caudal septal graft placement in open septorhinoplasty. In conjunction with previously reported case series, which demonstrated elevated risk of prolonged inflammation and infection, we would recommend avoidance of subcutaneous Dermabond as an adjunct, particularly in combination with PDS plate utilization.


Subject(s)
Abscess/etiology , Cyanoacrylates/adverse effects , Nasal Septum/surgery , Rhinoplasty , Tissue Adhesives/adverse effects , Abscess/microbiology , Absorbable Implants , Adult , Female , Humans , Polydioxanone , Postoperative Complications , Proteus mirabilis/isolation & purification , Retrospective Studies , Young Adult
9.
Laryngoscope ; 127(2): 349-353, 2017 02.
Article in English | MEDLINE | ID: mdl-27345583

ABSTRACT

OBJECTIVES: Reports of patient injuries associated with videolaryngoscopy are increasing in the literature. There are a wide variety of opinions regarding both safe use of the device and patient care following aerodigestive tract injury. We have seen an increase in videolaryngoscopy-associated injuries in recent years at our institution. Because of this, we wanted to determine if video-assisted laryngoscopy presents a greater risk of injury compared with direct laryngoscopy. Furthermore, we wanted to determine if there were patient and/or surgical factors that could contribute to patient injuries following videolaryngoscopy. DATA SOURCES: MAMC anesthesia records, PubMed, Ovid. REVIEW METHODS: We compared rates of injury between videolaryngoscopy to direct laryngoscopy at our institution by searching anesthesia records to identify laryngoscopy procedures that resulted in injury to the soft palate or oropharynx. We also identified 19 published cases in the literature, in addition to our cases, that we reviewed for patient characteristics (e.g., body mass index, age and sex, Mallampati grade), type of videolaryngoscope, location of injury, and type of repair (if any) required. RESULTS: At our institution, we have a statistically higher rate of injury using videolaryngoscopy compared to direct laryngoscopy. Our data also indicate that women are more commonly injured during videolaryngoscope intubation than men. The right tonsillar pillars and soft palate are the most frequently injured, with through-and-through perforation of the soft tissues being the most common type of injury. The most common repair of injuries required simple closures, and long-term harm was very rare. CONCLUSION: Our data suggests that using video-assisted laryngoscopy for intubation puts a patient at significantly greater risk for injury compared to direct laryngoscopy. Laryngoscope, 2016 127:349-353, 2017.


Subject(s)
Laryngoscopy/adverse effects , Pharynx/injuries , Video Recording , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Follow-Up Studies , Humans , Intubation, Intratracheal/adverse effects , Intubation, Intratracheal/instrumentation , Intubation, Intratracheal/methods , Laryngoscopy/instrumentation , Laryngoscopy/methods , Male , Middle Aged , Palate, Soft/injuries , Palatine Tonsil/injuries , Patient Safety , Risk Factors , Sex Factors
10.
JAMA Otolaryngol Head Neck Surg ; 143(3): 226-233, 2017 03 01.
Article in English | MEDLINE | ID: mdl-27893003

ABSTRACT

Importance: Segmental mandibulectomy for tumors that distort the buccal surface of the mandible present a reconstructive challenge. Objective: To determine whether mandible alignment after navigation-guided mandible reconstruction is better than alignment after non-template-assisted freehand reconstruction and as good as template-assisted reconstruction in a cadaveric trial. Design, Setting, and Participants: A cadaveric trial using 10 specimens was conducted at a tertiary academic center. Fiducials were created on the ramus to compare alignment with each intervention. Segmental mandibulectomy was performed on each cadaver. Each cadaver underwent navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction with plate contouring performed after mandibulectomy. The study was conducted from October 1, 2015, to January 1, 2016; data analysis was performed from February 1, 2016, to March 1, 2016. Interventions: Segmental mandibulectomy, navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction. Main Outcomes and Measures: Ramus fiducial coordinates were recorded at baseline and after each intervention. Mandible dimensions were measured using cephalometric landmarks. Postintervention and baseline differences in ramus and mandible position were calculated. Results: Ramus alignment was not significantly different between navigation-guided and template-assisted reconstruction, differing by 0.54 mm (98.3% CI, -0.38 to 1.47 mm). Non-template-assisted freehand reconstruction was associated with a 3.14-mm difference in alignment compared with template-assisted reconstruction (98.3% CI, 1.09 to 5.19 mm). Navigation-guided alignment resulted in a 3.69-mm improvement in alignment compared with non-template-assisted freehand reconstruction (98.3% CI, 1.79 to 5.58 mm). There was some improvement in the gonion-gonion and lingula mandibulae-lingula mandibulae (Lm-Lm) alignment for navigation-assisted compared with non-template-assisted freehand reconstruction by 1.97 mm (98.3% CI, -0.65 to 4.58 mm) and 1.39 mm (98.3% CI, -0.17 to 2.95 mm), respectively. There was marginal evidence of better Lm-Lm alignment for navigation-guided than template-assisted reconstruction (0.44 mm; 98.3% CI, -0.06 to 0.95 mm). Conclusions and Relevance: Mandible alignment following navigation-guided reconstruction is similar to template-assisted reconstruction. Navigation-guided alignment is likely better than non-template-assisted freehand reconstruction, and navigation guidance offers a reliable technique for real-time adjustment when reconstructing complex surgical defects, such as tumors effacing the buccal cortex of the mandible.


Subject(s)
Free Tissue Flaps , Mandibular Reconstruction/methods , Surgery, Computer-Assisted/methods , Cadaver , Humans
11.
Clin Plast Surg ; 43(4): 683-93, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27601392

ABSTRACT

This article discusses the lessons learned from nearly 2700 free tissue transfer procedures to reconstruct defects of the head and neck at the University of Washington. It discusses the authors' perioperative management practices regarding perioperative tracheotomy tube placement, their method of postoperative flap monitoring, and their current protocol for use of postoperative antibiotics. It reports on the reconstructive preferences for 2 difficult defects that frequently result in unfavorable outcomes: the total glossectomy defect and the pharyngolaryngectomy defect. Key points for harvesting and insetting flaps, to maximize reconstructive outcomes, are provided.


Subject(s)
Free Tissue Flaps/adverse effects , Head and Neck Neoplasms/surgery , Plastic Surgery Procedures/adverse effects , Wounds and Injuries/surgery , Free Tissue Flaps/blood supply , Head/surgery , Humans , Neck/surgery , Plastic Surgery Procedures/methods , Treatment Outcome , Wounds and Injuries/etiology
12.
Otolaryngol Clin North Am ; 45(5): 1109-26, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22980688

ABSTRACT

This article reviews the evidence for the evaluation and management for patients with dysphonia. The evidence behind laryngoscopy, laryngostroboscopy, laryngeal imaging, laryngeal electromyography, and disease-specific questionnaires are reviewed. The evidence for management of some of the common conditions leading to dysphonia is also reviewed. This article reviews the evidence for voice therapy for various voice pathologies; medical management of dysphonia, including antibiotics, steroids, and antireflux therapy; and surgical management of glottic insufficiency and some benign laryngeal masses.


Subject(s)
Dysphonia , Evidence-Based Practice , Hoarseness , Laryngoplasty , Laryngoscopy/methods , Voice Training , Anti-Bacterial Agents/therapeutic use , Disease Management , Dysphonia/diagnosis , Dysphonia/etiology , Dysphonia/therapy , Electromyography/methods , Gastrointestinal Agents/therapeutic use , Glucocorticoids/therapeutic use , Hoarseness/diagnosis , Hoarseness/etiology , Hoarseness/therapy , Humans , Laryngopharyngeal Reflux/complications , Laryngopharyngeal Reflux/drug therapy , Laryngoplasty/adverse effects , Laryngoplasty/methods , Neoplasms/complications , North America , Randomized Controlled Trials as Topic , Respiratory Tract Infections/complications , Respiratory Tract Infections/drug therapy , Treatment Outcome , Vocal Cord Paralysis/complications
13.
Adv Otorhinolaryngol ; 73: 132-6, 2012.
Article in English | MEDLINE | ID: mdl-22472245

ABSTRACT

Juvenile nasopharyngeal angiofibromas remain rare tumors representing approximately 0.05% of head and neck tumors. The typical presentation is a male teenager with recurrent epistaxis and nasal obstruction. These tumors were traditionally approached via external and/or intraoral incisions, but many are amenable to endoscopic removal. Preoperative embolization of major feeding vessels to these tumors by interventional radiology has resulted in significantly less blood loss and facilitated endoscopic resection. The following chapter discusses endoscopic resection of juvenile nasopharyngeal angiofibromas and outlines pertinent anatomy while covering important surgical techniques. Appropriate patient selection, anesthesia considerations, surgical preparation and techniques, and postoperative care are discussed. A case presentation is included with preoperative imaging and an accompanying video to demonstrate these surgical techniques.


Subject(s)
Angiofibroma/surgery , Endoscopy/methods , Nasopharyngeal Neoplasms/surgery , Adolescent , Humans
14.
Adv Otorhinolaryngol ; 73: 145-8, 2012.
Article in English | MEDLINE | ID: mdl-22472247

ABSTRACT

Dr. Leonard Furlow first described the double-reversing z-plasty technique for cleft soft palate repair in 1978. This approach allows for repair of an overt or submucous cleft palate, but just as an importantly, provides additional length to the palate and also realigns the palatal musculature. The Furlow palatoplasty (the name by which the procedure is commonly referred) has therefore been instrumental in the treatment of velopharyngeal insufficiency. The primary aims of this chapter are to provide the clinician with the indications for when to consider utilizing the Furlow palatoplasty and to give a stepwise description of how to perform the procedure.


Subject(s)
Cleft Palate/surgery , Palate, Soft/surgery , Plastic Surgery Procedures/methods , Cleft Palate/complications , Humans , Velopharyngeal Insufficiency/etiology , Velopharyngeal Insufficiency/surgery
15.
Otolaryngol Head Neck Surg ; 146(3): 461-6, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22166961

ABSTRACT

OBJECTIVE: The primary objective was to compare retention of knowledge of surgical risks in parents of children having an adenotonsillectomy who received a preoperative handout or watched a video, in addition to standard counseling. A secondary objective was to determine whether time from counseling to day of surgery affects risk retention. STUDY DESIGN: Prospective randomized control study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: The study, conducted March 2010 through April 2011, included participants who had children undergoing adenotonsillectomy. The preoperative and postoperative test scores of those undergoing verbal counseling, counseling with handout, or counseling with video were compared. RESULTS: Forty-five participants were tasked to identify 9 risks of adenotonsillectomy. Preoperatively, participants identified an average of 6.8 (95% confidence interval [CI], 6.2-7.3) in the counseling group, 7.3 (95% CI, 6.4-8.3) in the counseling and handout group, and 6.6 (95% CI, 5.9-7.3) in the counseling and video group (P = .32). Postoperatively, participants identified an average of 5.8 (95% CI, 4.9-6.7) in the counseling group, 6.5 (95% CI, 5.3-7.6) in the counseling and handout group, and 5.2 (95% CI, 4.1-6.3) in the counseling and video group (P = .19). Time between preoperative counseling and day of surgery was inversely correlated with postoperative score (ß -.34, P = .02). CONCLUSION: Participants were not able to identify all of the risks associated with adenotonsillectomy. There was no difference in identification of risks associated with adenotonsillectomy among different modalities of counseling. Participants retained more information when there was less time between the preoperative counseling and day of surgery.


Subject(s)
Adenoidectomy/methods , Multimedia/statistics & numerical data , Patient Education as Topic/methods , Postoperative Complications/prevention & control , Tonsillectomy/methods , Adenoidectomy/adverse effects , Child , Child, Preschool , Confidence Intervals , Counseling/methods , Female , Follow-Up Studies , Humans , Male , Parents/education , Patient Safety , Patient Satisfaction , Postoperative Complications/epidemiology , Preoperative Care/methods , Prospective Studies , Risk Assessment , Teaching Materials , Tonsillectomy/adverse effects , Treatment Outcome
16.
J Neurophysiol ; 90(2): 1235-44, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12711711

ABSTRACT

Saccades that consistently over- or undershoot their targets gradually become smaller or larger, respectively. The signal that elicits adaptation of saccade size is a difference between eye and target positions appearing repeatedly at the ends of saccades. Here we describe how visual error size affects the size of saccade adaptation. At the end of each saccade, we imposed a constant-sized error by moving the target to a specified point relative to eye position. We tested a variety of error sizes imposed after saccades to target movements of 6, 12, and 18 degrees. We found that the size of the gain change elicited in a particular experiment depended on both the size of the imposed postsaccade error and on the size of the preceding target movement. For example, imposed errors of 4-5 degrees reduce saccades tracking 6, 12, and 18 degrees target movements by an average of 18, 35, and 45%, respectively. The most effective errors were those that were 15-45% of the size of the initial target eccentricity. Negative errors, which reduce saccade size, were more effective in changing saccade gain than were positive errors, which increased saccade size. For example, for 12 degrees target movements, negative and positive errors of 2-6 degrees changed saccade gain an average of 35 and 8%, respectively. This description of the relationship between error size and adaptation size improves our ability to adapt saccades in the laboratory and characterizes the error sizes that will best drive neurons carrying the adaptation-related visual error signal.


Subject(s)
Adaptation, Physiological , Macaca mulatta , Saccades/physiology , Visual Perception/physiology , Animals , Male , Photic Stimulation
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