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Biomedical subjects

R Metson

Publications and source records attributed to R Metson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Endoscopic laser dacryocystorhinostomy.

Endoscopic laser dacryocystorhinostomy (DCR) enables an obstructed lacrimal sac to be opened through an intranasal approach, avoiding the need for a skin incision. The holmium:yttrium aluminum garnet (holmium:YAG) laser is well-suited for this procedure because of its properties of fiberoptic delivery, effective bone cutting, and precise soft-tissue coagulation. Efficient bone ablation is particularly important for primary DCR which requires removal of relatively thick bone along the lateral nasal wall to expose the lacrimal sac. Forty-six endoscopic laser DCRs were performed on 40 patients. There were no intraoperative or postoperative complications. The surgery successfully relieved lacrimal obstruction in 85% of patients. Endoscopic instrumentation allowed for the rapid identification and correction of intranasal causes of DCR failure, including ethmoid sinus disease and middle turbinate hypertrophy. Endoscopic laser DCR appears to be a safe and effective procedure which should be considered as an alternative to external DCR for the surgical treatment of nasolacrimal duct obstruction.

Adolescent↗
PubMed1994

Endoscopic orbital decompression.

Exophthalmos from Graves' disease can result in visual disability and cosmetic deformity. Surgical treatment of this disorder is now possible through an intranasal endoscopic approach that allows removal of the medial orbital wall and floor without an external incision. Endoscopic orbital decompression was performed on 22 orbits in 14 patients for treatment of progressive exophthalmos. Local anesthesia was used in five cases. Sixteen procedures involved a concurrent lateral orbital decompression performed through an external approach. There were no intraoperative or postoperative complications. Visual acuity remained stable or improved in all cases. Proptosis was reduced an average of 3.2 +/- 1.1 mm (range 2 to 4.5 mm) by endoscopic decompression alone. When a lateral decompression was also performed, proptosis was reduced by an additional 2.4 mm, for an average improvement of 5.6 +/- 1.7 mm (range 2 to 8 mm). Endoscopic orbital decompression appears to be a safe technique for the treatment of exophthalmos that can be performed effectively with the patient under general or local anesthesia.

Adult↗
PubMed1993

Holmium:YAG endonasal laser dacryocystorhinostomy.

Previously described techniques of endonasal laser-assisted dacryocystorhinostomy appear to offer several advantages over conventional external dacryocystorhinostomy, including the following: (1) decreased disruption of medial canthal anatomy, (2) enhanced hemostasis, and (3) avoidance of a cutaneous scar. Although good results were achieved, several limitations of early laser-assisted techniques have been noted, including difficulty in removal of the thick bone of the anterior lacrimal crest and inability to obtain specimens of lacrimal sac mucosa for biopsy purposes. In a series of 40 consecutive, primary endonasal dacryocystorhinostomy procedures, we used the holmium:YAG (Ho:YAG) laser for bone removal and endoscopic sinus surgical instrumentation to obtain lacrimal sac biopsy specimens. Intraoperative hemostasis was excellent and medial canthal scarring was avoided in all patients. The overall long-term ostium patency rate in our series was 82%. Several technical modifications adopted in the latter part of our series, including use of a small drill for supplemental bone removal, extensive removal of lacrimal sac mucosa, and use of a double stent, appeared to enhance this success rate.

Adolescent↗
PubMed1993

Botulinum A toxin for treatment of aberrant facial nerve regeneration.

Twelve patients with involuntary synkinetic eyelid closure were given 40 injections of botulinum A toxin. Temporary improvement in involuntary eyelid closure was observed in all 12 patients. Eleven of the 12 patients desired repeated injections. Dose requirements for this indication were compared with doses used in 697 injections in 112 patients with essential blepharospasm and Meige syndrome. Additionally, dose comparisons were made with 269 injections in 71 patients with hemifacial spasm. Dose requirements needed to treat aberrant regeneration of the facial nerve were substantially less than needed to treat blepharospasm and Meige syndrome. The dose requirement was similar to that in hemifacial spasm treatment. The reason for the differences probably relates to existing muscular denervation associated with hemifacial spasm and aberrant facial nerve regeneration.

Blepharospasm↗
PubMed1992

Videolaryngoscopy in the office--a critical evaluation.

In view of the growing popularity of office videolaryngoscopy, surprisingly little objective data exist as to its influence on clinical practice. We reviewed 150 consecutive laryngeal recordings in an attempt to determine what effect videolaryngoscopy has had on our practice and the patient care provided.

Adult↗
PubMed1992

Barium swallow is a predictor of salivary fistula following laryngectomy.

Pharyngocutaneous salivary fistula after laryngectomy is a serious complication that can lead to prolonged hospitalization and increased patient morbidity. A postoperative barium swallow provides the surgeon with information regarding the integrity of the pharyngeal suture line. In an attempt to determine whether this information can be used to predict or prevent salivary fistula, we reviewed the records of 109 patients who underwent total laryngectomy, including 51 who had a barium swallow before they began oral intake. Ten patients (20%) demonstrated a sinus tract originating from the pharyngeal suture line. A clinical salivary fistula developed in all four patients with a sinus tract 2 cm or longer, but in only one of six patients with a tract shorter than 2 cm. Other factors predictive of salivary fistula included tumor stage, previous radiation therapy, and the presence of concurrent postoperative complications. A single fistula developed in the 58 patients not studied with barium. Information provided by postlaryngectomy barium swallow appeared to predict, but not prevent salivary fistula formation.

Adult↗
PubMed1991

Endoscopic surgery for lacrimal obstruction.

Intranasal access to the lacrimal drainage system has been greatly enhanced with the advent of endoscopic nasal surgery. This technique has been used for the treatment of recurrent lacrimal obstruction after failed external dacryocystorhinostomy (DCR) in 12 patients. Improved intranasal visualization with the endoscope allowed easy identification and opening of the lacrimal sac, with no need for a skin incision. Obstructing intranasal pathology, including adhesions from previous DCR, an enlarged middle turbinate, and ethmoid sinus disease, was readily identified and corrected. There were no intraoperative complications. Lacrimal obstruction was completely relieved in nine of 12 patients (75%), with a followup of 7 to 25 months. Endoscopic revision DCR should be considered in patients with recurrent epiphora after external DCR.

Adult↗
PubMed1991

Magnetic stimulation of the facial nerve.

Intracranial activation of the facial nerve is now possible with the noninvasive techniques of magnetic stimulation. Brief magnetic pulses generated by a coil overlying the parietal scalp elicit compound muscle action potentials of similar shape and amplitude and greater latency than those produced by electroneurography. Mapping studies demonstrate the compound muscle action potentials to be of constant latency and varying amplitude with changing coil location. Maximum compound muscle action potential amplitudes are obtained with the coil center located in a rectangular area superior and posterior to the ear canal. A comparison of large and small diameter coils showed them to be equally effective for painless facial nerve stimulation; however, the smaller coil allowed for a more localized field of activation. Magnetic stimulation has the potential to provide cross-the-lesion testing of facial nerve function.

Action Potentials↗
PubMed1991

Preservation of the facial nerve in the management of recurrent pleomorphic adenoma.

Whether to preserve or sacrifice a facial nerve involved with benign neoplasm is one of the most difficult intraoperative decisions confronting the head and neck surgeon. We reviewed 21 cases of recurrent pleomorphic adenoma treated with subtotal excision and facial nerve preservation, followed by postoperative radiation therapy. Of the 17 patients with microscopic residual tumor at completion of surgery, 16 (94%) remain free of recurrence with an average follow-up of 5.9 years. Only one of four patients (25%) with a large postoperative tumor load remains free of disease. Facial nerve function is normal in 20 of 21 patients. Preservation of the facial nerve with postoperative irradiation should be considered as an alternative to nerve sacrifice in selected cases of recurrent pleomorphic adenoma.

Adenoma, Pleomorphic↗
PubMed1990

Nasopharyngeal mass: a manifestation of inflammatory otologic disease.

A nasopharyngeal mass with cranial neuropathies usually indicates an advanced neoplastic process. We present three patients with these findings and concurrent invasive Pseudomonas otitis in whom repeated nasopharyngeal biopsies were negative for tumor. All of the nasopharyngeal masses resolved following treatment of the otitis. Mechanisms of disease spread from the temporal bone to the nasopharynx are discussed. Clinicians may choose to modify diagnostic and therapeutic approaches to the nasopharyngeal mass in patients with concurrent invasive otologic disease.

Aged↗
PubMed1988

Facial nerve evoked potentials in the cat.

Electrophysiologic facial nerve testing usually involves stimulation of the peripheral nerve in order to make some indirect inference about nerve integrity at a more proximal site of lesion. In an attempt to develop a test of facial nerve function by use of across-the-lesion testing, the cat facial nerve was stimulated percutaneously at the stylomastoid foramen while retrograde activity through the temporal bone and cranium was monitored with scalp electrodes. A biphasic evoked potential could be identified within 3 milliseconds of stimulation with the use of a signal-averaging computer. This potential remained when the animal was paralyzed and disappeared when the facial nerve was cut proximal to the stimulation site. A potential of similar latency and duration but larger amplitude was recorded from the subarachnoid space. Mapping studies indicated its origin to be a dipole located between ipsilateral mastoid and parietal recording sites that corresponded to the region of the intracranial facial nerve. Optimal stimulation and recording techniques for subsequent studies of human beings are discussed.

Animals↗
PubMed1988

Surgical complications following twice-a-day versus once-a-day radiation therapy.

With increasing numbers of radiotherapists using twice-a-day (BID) rather than conventional once-a-day (QD) radiation therapy to treat carcinomas of the head and neck, we attempted to determine whether the increased tissue reaction seen with a BID program results in greater morbidity for subsequent surgery. Postoperative complications in 24 patients receiving prior BID irradiation were compared with 37 controls receiving QD treatments. The incidence of major surgical complications for BID and QD groups was equivalent (20.8% and 18.9%, respectively). The incidence of minor complications was almost three times greater for the BID group (37.5% vs. 13.5%). Patients receiving BID radiation therapy required twice as many intraoperative transfusions (2.13 vs. 1.11) and five additional days of postoperative hospitalization (23.7 vs. 18.2). These differences are statistically significant with p-values of less than 0.5 and less than 0.1, respectively. We consider this increase in surgical morbidity to be acceptable if BID radiation therapy leads to improved tumor control.

Combined Modality Therapy↗
PubMed1988

Internal maxillary artery ligation for epistaxis: an analysis of failures.

The records of 100 consecutive patients undergoing transantral ligation of the internal maxillary artery (IMA) for epistaxis, including 15 patients who developed postoperative bleeding, were reviewed. Preoperative parameters predictive of surgical failure were advanced age, anemia, and a history of hypertension. The causes of postoperative epistaxis, as determined by surgical reexploration or angiography in 12 cases, included failure to identify the IMA in the pterygomaxillary space (6 cases), blood flow through partially closed clips on the IMA (2 cases), bleeding from posterior ethmoid arteries (2 cases), and revascularization of the nasal blood supply (2 cases). The incidence of surgical failure may be reduced by proper techniques of IMA identification and ligation.

Epistaxis↗
PubMed1986

Tetracycline sclerotherapy for chylous fistula following neck dissection.

In chylous fistulas following radical neck dissections, we have found reexploration to be unrewarding, with infrequent identification of a specific leakage site intraoperatively and persistent fluid accumulation postoperatively. As an alternative, we injected tetracycline hydrochloride into the supraclavicular wound bed. This procedure resulted in a rapid, sustained decline in fistula output in two of three cases, avoiding surgical intervention. Tetracycline sclerotherapy has been described for treatment of intrathoracic and other intracavitary fluid collections. We believe that tetracycline sclerotherapy is an effective adjunct in the management of chylous fistulas following radical neck dissections and that this therapy should be attempted before surgical reexploration.

Adenocarcinoma↗