Biomedical subjects
Publications and source records attributed to D S Parsons.
This article portrays the anatomy of the ethmoid bone and lateral nasal wall in a detailed, but easily digested form. Understanding the anatomy of the lateral wall of the nose is the cornerstone of competent paranasal sinus surgery.
Powered instrumentation is now available for a variety of sinonasal procedures in children. Microdebriders with continuous suction at the operative site allow increased precision for complex procedures that often were difficult in small, fragile, pediatric noses. These instruments can be used for functional endoscopic sinus surgery in children and for such procedures as benign and malignant sinonasal or base of skull tumors, choanal atresia, complicated adenoidectomies, dacrocytorinostomies, septal spurs, and recurrent respiratory papillomatosis. These instruments can remove mucosa, neoplastic tissue, cartilage, thin bony septations, nasal debris, and blood under continuous endoscopic visualization. Edematous mucosa is not stripped, but trimmed and preserved, allowing much more rapid postoperative healing because exposed bone is avoided.
The posterior ethmoid air cells and the sphenoid sinuses have a complex anatomy that is surrounded by vital structures. To more easily protect these structures, three approaches are presented that make pediatric sphenoidotomy a safer procedure. The approaches include measuring the distance from the anterior nasal spine to the anterior and surgical posterior faces of the sphenoid sinus intraoperatively and comparing these to the patient's height and age, the use of the "ridge" to ensure a safe entry into the sphenoid, and, in patients where isolated sphenoid disease is present, the use of a powered instrument to enlarge the sphenoid ostium. The availability of measurements relating the height of the patient to the location of the sphenoid sinus, the use of the "ridge," and the use of powered instrumentation, should help the surgeon enter the sphenoid with greater confidence and achieve a more effective result.
Maxillary sinus disease often is exacerbated by a laterally displaced uncinate process that functionally obstructs the infundibulum and the natural ostium. The drainage pathway may be adequate during periods of wellness but with the introduction of nasal edema, the ostium/infundibulum interface is inadequate, thus preventing acceptable ventilation and drainage. Incomplete removal of the most anterior uncinate can keep the surgeon from identifying the natural ostium. Failure to relieve any obstruction from this important opening, with simultaneous creation of an MMA that does not include the natural ostium of the maxillary sinus, leads to the missed ostium sequence and continued sinus disease.
After cholinergic denervation of the hippocampus, via medial septal (MS) lesions, peripheral sympathetic fibers, originating from the superior cervical ganglia, grow into the hippocampus. In this study, we sought to determine the effect of hippocampal sympathetic ingrowth (HSI) on the M2 subtype of muscarinic cholinergic receptors, by examining the membrane binding of [3H]AF-DX 384 in hippocampal tissue from control rats, rats with HSI and rats with MS lesions + concurrent ganglionectomy (CD group). In dorsal hippocampus, Kd was found to be increased while Bmax was decreased in the CD group as compared with both the HSI and control group which did not differ from one another. In ventral hippocampus, Kd was found to be increased while Bmax was decreased in the CD group when compared only with the control group. These results suggest that sympathetic ingrowth, which has its greatest concentration in dorsal hippocampus, can 'normalize' the M2 receptor in hippocampus.
Following cholinergic denervation of the hippocampus by medial septal lesions, and unusual neuronal reorganization occurs, in which peripheral sympathetic fibers, originating from the superior cervical ganglia, grow into the hippocampus. Previously, we have found that both hippocampal sympathetic ingrowth (HSI) and cholinergic denervation (CD), alone, altered the total number and affinity of muscarinic cholinergic receptors (mAChR). In this study, we utilized the muscarinic antagonist [3H]Pirenzepine, in combination with membrane radioligand binding techniques, to determine the effects of HSI and CD on hippocampal M1 and M1 + M3 mAChR subtypes, 4 weeks after MS lesions. In both the dorsal and ventral hippocampus, HSI was found to markedly diminish the number of M1 AChRs, while CD was found to increase the number of M1 AChRs. Neither treatment affected the affinity of the M1 AChR. However, when M1 + M3 binding was assessed, CD was found to decrease the affinity in both hippocampal regions, without altering the number of receptors. Neither affinity nor number of M1 + M3 receptors was altered by HSI. The results of this study suggest that both cholinergic denervation and hippocampal sympathetic ingrowth uniquely affect hippocampal muscarinic receptors.
Following cholinergic denervation of the hippocampus by medial septal (MS) lesions, an unusual neuronal reorganization occurs in which peripheral sympathetic fibers, originating from the superior cervical ganglia, grow into the hippocampus (hippocampal sympathetic ingrowth; HSI). Previously, we have found that with MS lesions, animals with (the HSI(+) group) and without (HSI(-) group) ingrowth differed in carbachol stimulated PI hydrolysis, in PKC activity, and in muscarinic cholinergic receptors (mAChR). In this study, performed in hippocampal slices obtained four weeks after MS lesions, we utilized the hydrophilic muscarinic antagonist [3H]N-methylscopolamine ([3H]NMS) and hydrophobic muscarinic antagonist [3H]quinuclidinyl benzilate ([3H]QNB) in the presence of either 4-alpha-phorbol or phorbol 12,13-dibutyrate (PDBu) to determine the effect of MS lesions with and without ingrowth on PKC-mediated mAChR internalization. In the presence of PDBu, a group effect was observed in [3H]NMS binding, with control groups > HSI(+) group > HSI(-) group. However, [3H]QNB binding was similar across groups. These results suggest that the cholinergic denervation of the hippocampus enhances the internalization of mAChRs, which is modified in the presence of HSI.
OBJECTIVE: To review the clinical features, associated congenital abnormalities, management, and morbidity of infants presenting with posterior laryngeal and laryngotracheal clefts. DESIGN: Case series. SETTING: Great Ormond Street Hospital for Sick Children NHS Trust, London, England. PATIENTS: Consecutive sample of 44 patients presenting with posterior laryngeal and laryngotracheal clefts between December 10, 1979, and January 30, 1992. MAIN OUTCOME MEASURES: Clinical features, incidence of surgery, and associated morbidity and mortality related to different types of airway cleft. RESULTS: The main presenting features were stridor and aspiration, which were more evident with the more extensive clefts. Twenty-five patients (56%) had associated congenital abnormalities. Fourteen patients (32%) were treated conservatively. Sixteen patients (36%) underwent primary endoscopic surgical repair. Eight patients (18%) underwent primary repair via an anterior laryngofissure; and six patients (14%) underwent primary repair via a lateral pharyngotomy. Eight patients (18%) required revision surgery, two (4%) of them on more than one occasion. Ten patients (23%) required fundoplication to control gastroesophageal reflux. Six patients (14%) died. CONCLUSIONS: The identification of an airway cleft requires a high index of suspicion. Morbidity and mortality are reduced by securing the airway, controlling gastroesophageal reflux, and using a multidisciplinary pediatric team. We recommend the anterior laryngofissure because of the ease of surgical access.
Twenty-nine consecutive patients with cystic fibrosis were offered functional endoscopic sinus surgery. Twenty-six of these patients underwent surgery. A symptom questionnaire was obtained from the patient or parent before surgery. At the end of the study this symptom questionnaire was again administered to the same individual, and 21 completed it. There were 14 male and 7 female patients, with a mean age of 12.3 years and a median age of 8.7 years. Mean follow-up was 34.3 months. Results for the following symptoms were significant: nasal airway obstruction was improved (p < 0.0002), olfactory function was improved (p < 0.0037), purulent nasal discharge was decreased (p < 0.001), and activity level was increased (p < 0.001). Other parameters are also reported in the text. In summary, this study prospectively studies the effects of functional endoscopic sinus surgery on symptoms in patients with cystic fibrosis. The study points out several significant areas of symptom improvement and supports the selective use of functional endoscopic sinus surgery in patients with cystic fibrosis. Indications for surgery are provided.
Cholinergic denervation of the hippocampus by medial septal (MS) lesions results in the ingrowth of peripheral sympathetic fibers, originating from the superior cervical ganglia, into the hippocampus. To determine the effect of hippocampal sympathetic ingrowth (HSI) [3H]-QNB (L-quinuclidinyl [benzilic-4,4(n)] binding was assessed in the dorsal and ventral hippocampus four weeks after MS lesions. In dorsal hippocampus, HSI was found to significantly increase the number (Bmax) of [3H]-QNB binding sites and to normalize the decrease in affinity found in animals with MS lesions plus ganglionectomy (i.e., no ingrowth). In ventral hippocampus, HSI was found to normalize the increased number of binding sites and decreased affinity found in animals with MS lesions without ingrowth. No effect on either Kd or Bmax was found in animals that had undergone ganglionectomy with sham MS lesions. These results suggest that HSI can induce changes in hippocampal muscarinic cholinergic receptors.
Following cholinergic denervation of the hippocampal formation, via medial septal (MS) lesions, sympathetic fibers, originating from the superior cervical ganglia, growth into the hippocampus. Previous studies have demonstrated a sexually dimorphic effect of this neuronal rearrangement on recovery of a spatial-learning task, with this rearrangement being detrimental in male but protective in female rats. Circulating male sex hormones were found to interact with this effect in male animals. In this study we assessed the role of circulating female sex hormones on the behavioral and biochemical effects of hippocampal sympathetic ingrowth (HSI). For the behavioral studies female rats underwent either sham ovariectomy (sham OVARX) or OVARX and were taught a standard radial-8-arm maze task. Following attainment of criterion, animals underwent one of three surgical procedures: sham surgery; MS lesions+sham ganglionectomy (MS); HSI group; MS lesions+ganglionectomy (MSGx). As in our previous study, animals with HSI (i.e. MS group) were found to recover learning faster (in fact, these animals did not differ from controls) than animals with MS lesions without HSI. Gonadal status did not affect this behavioral recovery. For the biochemical studies hippocampal norepinephrine (NE) and choline acetyltransferase (ChAT) were measured in animals sham OVARX and OVARX, 8-12 weeks after the neurosurgical procedure. MS lesions (i.e. MSGx; MS) were found to reduce ChAT activity, regardless of circulating sex hormones. In controls NE levels were similar between OVARX and sham OVARX. NE levels were markedly elevated in the OVARX MS group compared to all other groups including sham OVARX. In the MSGx groups, NE levels were reduced compared to controls, while comparisons between these groups revealed a significant reduction in NE levels in the OVARX MSGx group compared to sham OVARX MSGx group. These studies suggest that female circulating sex hormones interact with brain injury in a very complex manner. However, this interaction does not appear to mediate the changes in behavior observed after HSI.
Hunter's syndrome is one of a group of heritable metabolic disorders caused by decreased activity of one or more of the lysosomal enzymes responsible for mucopolysaccharide catabolism, resulting in excessive deposition of mucopolysaccharides in skeletal and soft tissues. Pulmonary conditions, such as airway obstruction, sleep apnea syndrome, atalectasis, recurrent pneumonia and difficult endotracheal intubation are known to be associated with these rare disorders and have been reported. We report the findings at laryngotracheobronchoscopy of a patient with Hunter's syndrome with airway symptoms and, supported by analysis of previously reported cases of airway problems associated with the syndrome, suggest that tracheobronchomalacia with classifiable major airway collapse (MAC) may be the pathological correlate for this clinical picture. The endoscopic technique and characteristic findings of tracheobronchomalacia/MAC are discussed, as well as the natural history and pathophysiology of this condition, which is characterized by weakness of the tracheal wall due to softening of the supporting cartilage and hypotonia of the myoelastic elements with reduction in the tracheal lumen.
The relationship between cystic fibrosis (CF) and sinus disease has been appreciated since at least 1959. Unfortunately the standard methods used to treat sinus disease have been very unrewarding in the CF patients. We evaluated the long-term results achieved on 17 patients with CF that underwent FES surgery between July 1988 and January 1991. This group consisted of 16 pediatric and 1 adult patients with previously diagnosed CF, documented chronic sinus disease and nasal polyposis that had failed long-term maximal medical management. The patients, or their parents, were contacted and asked to rate the severity and frequency of their symptoms associated with chronic sinus disease, pre- and postoperatively. The specific symptoms evaluated were nasal obstruction, nasal discharge, postnasal drip, halitosis and cough. In addition, we attempted to measure the number of hospitalizations and the presence and frequency of headaches. We were able to show that, while there was no change in the relative health of patients as measured by the number of hospitalizations, there was a significant improvement in the quality of life. There was a marked decline in the frequency of nasal obstruction, nasal discharge and postnasal drip and a high level of patient satisfaction with the procedure. No changes were seen in the frequency or nature of the cough, halitosis or headache.
Squamous cell carcinoma of the tongue is rare in children and previously unreported as a second malignancy after survival of acute leukemia. Usual etiologic associations such as smoking and alcohol use are not commonly seen in this population, and exposure to immunosuppressive and antineoplastic agents including radiation therapy may contribute to the occurrence of these tumors. A review of the literature reveals only 21 previously reported cases of squamous cell carcinoma of the tongue in children less than 15 years old, and in only two cases was it a second malignancy; none were in leukemia survivors. Small numbers prevent accurate conclusions with regard to tumor behavior, but prognosis appears to be poor with aggressive invasion and early metastasis common. Follow-up of survivors of leukemia and its therapy with immunosuppressive and cytotoxic drugs and radiation should include regular careful head and neck examinations.
The tracheoscope is a bronchoscope without the side ventilating ports at the distal tip. It has been used for decades, implementing diagnostic and therapeutic procedures in the subglottis and cervical and thoracic trachea. The closed tube tracheoscope allows excellent control of the airway with maintenance of continuous anesthesia and ventilation. Flexible fiber-directed lasers, such as the potassium-titanyl phosphate laser, can be used with the tracheoscope for laser resection or vaporization of diseased tissue from just below the vocal cords to any level within the trachea. Controlled anesthesia and smoke evacuation are maintained throughout the operation, allowing a relatively safe endoscopic procedure. Disorders such as subglottic hemangioma, subglottic or tracheal webs, papillomatosis, granuloma, and a variety of neoplastic growths can be excised, debulked, or submitted to biopsy by means of this instrument. In the neonatal and infant airway, use of the tracheoscope concomitantly with rigid telescopes has been particularly rewarding.
The impact of chronic sinusitis on children has become more apparent as the awareness of the disease has increased. Consequently, the knowledge of its effect in the pediatric patient has expanded dramatically. Functional endoscopic sinus surgery (FESS) has become the primary surgical modality for treatment of this illness in children who have not responded to optimal medical management. A retrospective study was conducted in patients from 7 months to 17 years of age who were treated with FESS for chronic sinusitis refractory to medical therapy. Using a comprehensive parental questionnaire and a review of the medical charts, results were analyzed from these post-FESS children. Parents of the children were interviewed with a mean follow-up time of 21.8 months postoperatively. Factors discussed included chronic nasal obstruction, purulent nasal discharge, postnasal drip, chronic cough, halitosis, headaches, behavioral problems, allergies, and asthma symptoms. This preliminary investigation suggests that FESS is effective in treating medically recalcitrant severe chronic sinusitis in children.
Primary ciliary dyskinesia (PCD) is an inherited disorder manifested in children as chronic otomastoiditis, recurrent pneumonia, and chronic sinusitis. The failure of the ciliary beat pattern to effectively function in the respiratory tract produces stasis of secretions with secondary inflammation, edema, and infection. The authors report three young children with PCD who presented with variable severities of symptoms. Each had the aforementioned respiratory tract problems. The child with the most severe symptomatology was treated with a variety of medical options, including long-term gamma globulin injections, but hospitalizations persisted twice per month because of severe sinopulmonary illness. All three of the children underwent functional endoscopic sinus surgery (FESS). In addition, two children received pressure equalization (PE) tubes. One child required a revision procedure. Their surgical outcomes are discussed. Follow-up of FESS in three children with this disorder shows a marked improvement in symptomatology with a decreased incidence of hospitalization and a somewhat decreased need for medical therapy.
Injury to the lacrimal drainage system with resultant epiphora is a complication of functional endoscopic sinus surgery. A study of 24 patients was conducted to determine the incidence and significance of lacrimal drainage system injuries during functional endoscopic sinus surgery. Intraoperative testing demonstrated seven occult injuries (15%) in 46 endoscopic procedures. Postoperative testing demonstrated diversion of lacrimal drainage into the middle meatus in two patients and spontaneous healing of the injured lacrimal drainage system with restoration of normal drainage in three of the patients available for follow-up testing. In no patient did epiphora develop. It is concluded that the nasolacrimal drainage system is in close proximity to the dissection cavity during functional endoscopic sinus surgery and, hence, is at risk for inadvertent injury. Occult damage to the nasolacrimal drainage system would appear to be a common event during functional endoscopic sinus surgery; however, the complication of postoperative epiphora is rare.