Involuntary cough is superior to voluntary cough for identifying stress urinary incontinence.

INTRODUCTION: Voluntary cough (VC) and the laryngeal expiration reflex (LER) provoke stress urinary incontinence (SUI). The aim of this article is to analyze the effectiveness of these stimuli on the timing of urinary leaks. MATERIAL AND METHODS: Urodynamic testing using pressure catheters was performed on 123 subjects with history of SUI. The LER was triggered using the induced reflex cough test (iRCT). Each subject was tested with VC and LER and leaked with one or both stimuli. The occurrence and timing of leaks were recorded. RESULTS: The peak and average intra-abdominal pressures were 16-19% greater for LER compared to VC. Of the 123 subjects, LER caused leak in 118 (96%), VC in 71 (58%) and both in 66 (54%). For LER compared to VC, leak was more likely to occur during or immediately after the first expiratory effort. The electromyogram for VC and LER were similar. CONCLUSIONS: The iRCT reliably initiated the LER and triggered SUI more effectively than VC. During VC, the smooth muscle of the internal urethral sphincter (IUS) starts to contract during inspiration, and constriction of the IUS continues into the expiratory phase; this increased urethral tonicity would lessen the likelihood of SUI. We refer to this as the inspiration closure reflex (ICR). With LER the inspiration would not take place, and the first expiratory effort would be against a non-constricted IUS, making leak more likely. Our findings disprove the pressure transmission theory. The internal and external urethral sphincters may both increase urethral closure pressure and resistance.

Location of the Internal Mammary Vessels for Microvascular Autologous Breast Reconstruction: The "1-2-3 Rule".

BACKGROUND: Postmastectomy breast reconstruction provides psychosocial benefits in self-esteem, sexuality, and quality of life. Autologous procedures yield the highest overall patient satisfaction compared with implant-based breast reconstruction as the gold standard. The internal mammary vessels are the preferred recipient vessels for free flap breast reconstruction. The purpose of this study is to provide surgeons with a reliable method for locating the vessels intraoperatively. METHODS: The internal mammary vessels were dissected bilaterally on 30 cadaveric specimens. Distances from the lateral sternal borders and the costochondral junctions to the internal mammary vessels at the second, third, and fourth costal levels were recorded. Descriptive bifurcation patterns were recorded. Initial dissection practicums were performed using the proposed safer dissection zone according to quantitative data. RESULTS: Sixty internal mammary arteries and 120 internal mammary veins were studied at three costal levels, resulting in 180 sets of measurements. Distances from the lateral sternal border to the medial internal mammary vein were 6.12, 9.04, and 10.45 mm at costal levels 2, 3, and 4, respectively. Mean distances between costochondral junctions and internal mammary arteries were 12.80, 24.78, and 33.28 mm at costal levels 2, 3, and 4, respectively. Most internal mammary vein bifurcated at the third costal level, and the left side bifurcated higher than the right. Dissection practicums revealed that the proposed dissection zone was consistently reliable in locating the vessels. CONCLUSIONS: This study provides mean measurements from common bony landmarks to the internal mammary vessels, equipping surgeons with a reliable zone of dissection for recipient vessel exposure. This may decrease morbidity and improve outcomes in autologous breast reconstructions.

What Is the Lobular Branch of the Great Auricular Nerve? Anatomical Description and Significance in Rhytidectomy.

BACKGROUND: Current literature suggests that preserving the lobular branch of the great auricular nerve has greater impact on sensory function of the auricle than preservation of the posterior branch during rhytidectomy. However, no methodology exists to efficiently and accurately determine the topographic location of the lobular branch. This study describes the branching characteristics of the lobular branch and algorithmic surface markings to assist surgeons in preservation of the great auricular nerve during rhytidectomy flap elevation. METHODS: The lobular branch was dissected in 50 cadaveric necks. Measurements were taken from the lobular branch to conchal cartilage, tragus, and antitragus. The anterior branch was measured to its superficial musculoaponeurotic system insertion, and the posterior branch was measured to the mastoid process. The McKinney point was marked and the great auricular nerve diameter was recorded. Branching pattern and location of branches within the Ozturk 30-degree angle were documented. Basic statistics were performed. RESULTS: The lobular branch was present in all specimens and distributed to three regions. In 85 percent of specimens, the lobular branch resided directly inferior to the antitragus; in the remaining specimens, it was located directly inferior to the tragus. Preoperative markings consisting of two vertical lines from the tragus and antitragus to the McKinney point can be used to outline the predicted location of the lobular branch. CONCLUSIONS: This study delineates the location of the lobular branch of the great auricular nerve. The authors translate these findings into a quick and simple intraoperative marking, which can assist surgeons in avoiding lobular branch injury during rhytidectomy dissection.

Inspiration closure reflex: the effect of respiration on intrinsic sphincters.

INTRODUCTION: The functions of the lower esophageal sphincter (LES) and internal urethral sphincter (IUS) have not been reported during voluntary and involuntary respiratory maneuvers. METHODS: In this study we performed a prospective barium videofluoroscopy study (BSV) of the LES on 4 healthy adult men during voluntary cough (VC), laryngeal expiration reflex (LER), breath-hold maneuvers, and normal inspiration. One subject had fiber-optic pressure catheters placed in the LES and IUS, and electromyographic recording of the right T7-8 intercostals during respiration. RESULTS: BSV showed closure and relaxation of the LES corresponding to the inspiration and expiration of VC. The LES was patent during the LER. There was closure of the LES during the deep inspiration/breath-hold event. Pressure catheters in the LES and IUS showed increased pressure during inspiration. CONCLUSIONS: These observations suggest that pulmonary inspiration afferents elicit a patterned reflex motor response in the LES and IUS, referred to as the inspiration closure reflex (ICR).

Teaching of anterior cruciate ligament function in osteopathic medical education.

The anterior cruciate ligament (ACL) of the knee and the function of its anteromedial (AM) and posterolateral (PL) bundles are a focus of orthopedic research. Because of the probability that third-year and fourth-year osteopathic medical students will encounter ACL injuries during clinical rotations, it is of paramount importance that students fully understand the functions of the AM and PL bundles as 2 distinct functional components of the ACL. The authors assess the degree to which the AM and PL bundles are discussed within basic science curricula at colleges of osteopathic medicine (COMs). In September 2008, a 6-question survey addressing various aspects of ACL education was mailed to instructors of lower-extremity anatomy at all 28 COMs that existed at that time. Nine of the 21 responding institutions (42.9%) indicated that both the AM and PL bundles of the ACL are discussed within their basic science curricula. Four of these 9 COMs indicated that their instruction mentions that the bundles are parallel in extension and crossed in flexion. Nine of the 21 responding COMs (42.9%) indicated that they instruct students that the AM bundle is a major anterior-posterior restrictor, and 12 (57.1%) indicated that they instruct students that the PL bundle is the major rotational stabilizer of the ACL. In 7 of the 21 responding COMs (33.3%), the AM and PL bundles are identified via direct visualization during anatomic dissection of the ACL. The authors conclude that their findings suggest the need for enhanced presentation of the AM and PL bundles within the basic science curricula at COMs to provide osteopathic medical students with a more comprehensive education in anatomy.

Anatomic changes related to laryngeal descent from birth to 1 year of age: do they play a role in SIDS?

We conducted a retrospective study to measure laryngeal descent in human infants and to determine if there is any correlation between the associated anatomic changes and the timing of the peak incidence of sudden infant death syndrome (SIDS), which is 2 to 4 months of age. We performed a computerized search of hospital records at our institution to identify magnetic resonance imaging (MRI) scans of the head and neck and plain radiographs of the lateral neck in patients younger than 1 year of age (range: 1 to 357 days). After unusable images were excluded, 79 head and neck MRI scans and 111 lateral neck x-rays were suitable for study. Two measurements were taken from each image: one from the tip of the epiglottis to the uvula and one from the tip of the epiglottis to the center of the sella turcica. These measurements were then graphed against the subject's age. SPSS statistical software was used to determine growth curves of the various measurements. The first derivative of these curves was calculated to determine the rate of laryngeal descent at a given age. We found that most subjects did not have an overlapping epiglottis and uvula during the first few months of life. The rate of laryngeal descent, based on measurements of the distance between the epiglottis and uvula, gradually increased in a near-linear fashion from as low as 0.005726 mm/day at day 1 of life to as high as 0.028366 mm/day at 300 days of age. We found no sharp increase in the rate of descent at 2 to 4 months of age, and thus no support for our hypothesis that there might be a correlation between anatomic changes and the peak incidence of SIDS.

Intra-abdominal pressures during voluntary and reflex cough.

BACKGROUND: Involuntary coughing such as that evoked from the larynx, the laryngeal cough reflex (LCR), triggers a coordinated contraction of the thoracic, abdominal and pelvic muscles, which increases intra-abdominal pressure (IAP), displaces the diaphragm upwards and generates the expiratory force for cough and airway clearance. Changes in the IAP during voluntary cough (VC) and the LCR can be measured via a pressure catheter in the bladder. This study evaluated the physiological characteristics of IAP generated during VC and the LCR including peak and mean pressures and calculations of the area under the curve (AUC) values during the time of the cough event or epoch. METHODS: Eleven female subjects between the ages of 18 and 75 underwent standard urodynamic assessment with placement of an intravesicular catheter with a fiberoptic strain gauge pressure transducer. The bladder was filled with 200 ml of sterile water and IAP recordings were obtained with VC and the induced reflex cough test (RCT) using nebulized inhaled 20% tartaric acid to induce the LCR. IAP values were used to calculate the area under the curve (AUC) by the numerical integration of intravesicular pressure over time (cm H2O.s). RESULTS: The mean (+/- SEM) AUC values for VC and the LCR were 349.6 +/- 55.2 and 986.6 +/- 116.8 cm H2O.s (p < 0.01). The mean IAP values were 45.6 +/- 4.65 and 44.5 +/- 9.31 cm H2O (NS = .052), and the peak IAP values were 139.5 +/- 14.2 and 164.9 +/- 15.8 cm H2O (p = 0.07) for VC and LCR, respectively. CONCLUSION: The induced LCR is the involuntary rapid and repeated synchronous expiratory muscle activation that causes and sustains an elevated IAP over time, sufficient for airway protection. VC and LCR have different neurophysiological functions. Quantification of the LCR using AUC values and mean or peak IAP values may be useful as a clinical tool for determining neurophysiological airway protection status and provide a quantitative assessment of changes in a patient's functional recovery or decline.

Effect of stroke location on the laryngeal cough reflex and pneumonia risk.

BACKGROUND: The purpose of this study was to evaluate the risk of developing pneumonia in acute stroke patients comparing the early anatomical stroke location and laryngeal cough reflex (LCR) testing. METHODS: A prospective study of 818 consecutive acute stroke patients utilizing a reflex cough test (RCT), which assesses the neurological status of the LCR compared to magnetic resonance imaging or computerized tomography for stroke location and subsequent pneumonia outcome. Stroke diagnosis and stroke location were made by a neurologist and clinical radiologist, respectively; both were blinded to the RCT results. RESULTS: Brainstem (p-value < .007) and cerebral strokes (p-value < .005) correlated with the RCT results and pneumonia outcome. Of the 818 patients, 35 (4.3%) developed pneumonia. Of the 736 (90%) patients who had a normal RCT, 26 (3.5%) developed pneumonia, and of the 82 (10%) patients with an abnormal RCT, 9 (11%) developed pneumonia despite preventive interventions (p-value < .005). The RCT had no serious adverse events. CONCLUSION: The RCT acted as a reflex hammer or percussor of the LCR and neurological airway protection and indicated pneumonia risk. Despite stroke location, patients may exhibit "brainstem shock," a global neurological condition involving a transient or permanent impairment of respiratory drive, reticular activating system or LCR. Recovery of these functions may indicate emergence from brainstem shock, and help predict morbidity and mortality outcome.

Electrophysiologic latency to the external obliques of the laryngeal cough expiration reflex in humans.

OBJECTIVE: The purpose of this study was to trigger the laryngeal cough expiration reflex using inhaled tartaric acid aerosol and to record the latency between the time of initiation of the laryngeal cough expiration reflex component of the laryngeal cough reflex and the onset of electromyographically recorded responses in the external abdominal oblique in humans. DESIGN: Five male subjects were tested in the seated position, and four latencies were recorded for each subject. The latencies were recorded from laryngeal stimulation to an electromyogram in the muscle belly of the left external abdominal oblique. The time line was activated by a microswitch attached to a breath-activated nebulizer. Data were analyzed using SPSS for mean latency and standard deviation. RESULTS: The mean (standard deviation) latency to the external abdominal oblique muscle was 17.6 +/- 10.6 msec. No adverse events to inhalation were reported. CONCLUSION: SIn humans, nebulized tartaric acid stimulates primarily rapid adapting receptors in the supraglottic larynx rather than C-fiber receptors. This receptor location in humans evolved neurologically to protect the airway during speech and swallowing, making the laryngeal cough expiration reflex an inseparable component of the laryngeal cough reflex, thus making it clinically significant when assessing airway protection.

Effect of tartaric acid-induced cough on pulmonary function in normal and asthmatic humans.

OBJECTIVE: The laryngeal cough reflex and the laryngeal cough expiratory reflex are brainstem reflexes that protect the upper airway from significant aspiration. The purpose of this investigation was to examine the effects of tartaric acid-induced cough on pulmonary function in normal healthy and asthmatic individuals. DESIGN: Twenty healthy and 20 asymptomatic, medicated, asthmatic volunteers engaged in a two-part evaluation of pulmonary function testing. All 40 subjects were nonsmokers. The reflex cough test, a 20% solution of prescription-grade L-tartaric acid dissolved in 0.15 M NaCl solution, initiated the laryngeal cough expiratory reflex/laryngeal cough reflex. The solution was placed in a Bennett Twin nebulizer and inhaled as a microaerosol. Pulmonary function testing was with a Spiromate AS-600. Baseline pulmonary function testing was initially performed, followed by two separate inhalations of the reflex cough test. The pulmonary function testing was repeated 5 min after the second reflex cough test. RESULTS: Statistically significant changes seen after the reflex cough test included increases in the peak inspiratory flow in normal subjects (P = 0.004) and in the peak expiratory flow in asthmatic subjects (P = 0.014). No respiratory adverse events occurred after the reflex cough test. CONCLUSIONS: Explanations for these findings include the possibility that tartaric acid-induced cough produces central nervous system-mediated bronchodilatation, through the cough itself or by secondary mechanisms.

Effect of acute unilateral middle cerebral artery infarcts on voluntary cough and the laryngeal cough reflex.

OBJECTIVE: The purpose of this study was to assess the effect of acute unilateral middle cerebral artery (MCA) infarctions in right-handed subjects on their ability to elicit voluntary cough (VC), and separately to assess the laryngeal cough reflex using the reflex cough test. DESIGN: This prospective, clinical study involved 30 right-handed, alert subjects with no previous history of stroke or asthma and with an infarction of the MCA distribution as seen on computed tomographic or magnetic resonance images. Subjects could follow verbal commands. A total of 16 subjects had right MCA infarcts and 14 had left MCA infarcts. VC responses and reflex cough test results were compared with the side of the infarct. The reflex cough test used nebulized tartaric acid. RESULTS: The laryngeal cough reflex was normal in all 30 subjects, irrespective of side of MCA infarction, and none developed aspiration pneumonia. Eleven of the 14 subjects who had a left MCA infarct had an abnormal VC (78.6%) and showed cough apraxia. All 16 subjects with right infarcts produced a VC. Subjects with left infarcts were more likely to have an abnormal VC than those subjects with right lesions (P < 0.001). CONCLUSIONS: VC is of limited use in screening subjects for aspiration pneumonia risk. A normal laryngeal cough reflex indicated a neurologically protected airway.