Radiofrequency energy tissue ablation for the treatment of nasal obstruction secondary to turbinate hypertrophy.

OBJECTIVE/HYPOTHESIS: We hypothesized that the success rate of radiofrequency energy (RFe) tissue ablation of the inferior turbinate for nasal obstruction achieved by previous investigators would be improved by using a longer needle electrode and creating two lesions per turbinate. METHODS: Ten patients with nasal obstruction secondary to inferior turbinate hypertrophy were prospectively enrolled. A 40-mm needle delivered RFe to two sites in each inferior turbinate. Patients used a visual analog scale (VAS) to grade nasal obstruction preoperatively and at 1 week and 8 weeks after surgery. Preoperative and postoperative digital images of the nasal cavity were graded for obstruction (0% to 100%) in a blinded manner. RESULTS: All patients (100%) were subjectively improved at 8 weeks. Mean obstruction (VAS) improved from 50%+/-21% to 16%+/-15% (right side) and from 53%+/-29% to 13%+/-13% (left side). Mean improvements were 68% (right side) (P = .004) and 75% (left side) (P = .001). Mean obstruction graded during blinded review of nasal cavity images improved from 73.5%+/-8% to 51%+/-8% (right side) and from 76%+/-6% to 64%+/-7% (left side). Of nine patients using medications for nasal obstruction before treatment, eight (89%) noted no further need for medications at 8 weeks. CONCLUSION: The use of RFe for submucosal tissue ablation in the hypertrophied inferior turbinate is an effective modality for reducing symptoms of nasal obstruction. Improved results may occur by using a longer needle and creating two lesions per turbinate. Of patients in this study, 100% reported improvement of nasal obstruction.

Cephalometric parameters after multilevel pharyngeal surgery for patients with obstructive sleep apnea.

Cephalometric studies have shown narrowing in the upper airway at multiple levels in patients with obstructive sleep apnea. Uvulopalatopharyngoplasty (UPPP), mandibular osteotomy with genioglossus advancement, and hyoid myotomy with advancement address narrowing in the retropalatal and retrolingual regions. In an effort to relate postoperative clinical changes to anatomic changes, cephalometric studies were performed on 44 patients who underwent multilevel pharyngeal surgery (UPPP, genioglossus advancement, hyoid myotomy with advancement). Both pre- and postoperative radiographs were available for 23 of these patients. The posterior airway space (P = .09), minimal posterior airway space (P = .04), posterior uvular space (P = .06), mandibular plane-to-hyoid distance (MP-H) (P = .06) and central incisor-to-tongue base distance (P = .02) all improved after surgery. None of the measurements of the posterior airway were significantly different between responders and nonresponders. The degree of collapse of the palate on modified Müller maneuver was highly correlated with the severity of sleep apnea as measured by the respiratory disturbance index; the collapse of the lateral pharyngeal walls was moderately correlated; and collapse of the base of tongue was not correlated. Cephalometric radiographs may reflect the anatomic changes that result from upper airway surgery for sleep apnea, but these changes are not useful for assessing surgical efficacy. The modified Müller maneuver, however, may represent a more predictive evaluation.

The failing flap in facial plastic and reconstructive surgery: role of the medicinal leech.

OBJECTIVE: To review the use of the medicinal leech, Hirudo medicinalis, in salvaging the failing, venous-congested flap. A protocol for the use of leeches is presented. Four illustrative cases of failing flaps (pectoralis major, midline forehead, and temporalis) are presented. STUDY DESIGN: Literature review comprised of MEDLINE search 1965 to present. Retrospective review of four cases involving the management of the failing, venous-congested flap. METHODS: A retrospective review of four cases of failing, venous-congested flaps was performed. RESULTS: The authors' experience, as well as the data from the reviewed medical literature, demonstrates the importance of early intervention in order to salvage the failing, venous-congested flap. Leeches are an immediate and efficacious treatment option. CONCLUSIONS: 1. Review of the literature indicates that the survival of the compromised, venous-congested flap is improved by early intervention with the medicinal leech. H medicinalis injects salivary components that inhibit both platelet aggregation and the coagulation cascade. The flap is decongested initially as the leech extracts blood and is further decongested as the bite wound oozes after the leech detaches. 2. When a flap begins to fail, salvage of that flap demands early recognition of reversible processes, such as venous congestion. The surgeon must be familiar with the use of leeches and should consider their use early, since flaps demonstrate significantly decreased survival after 3 hours if venous congestion is not relieved. In the four cases presented, a standardized protocol facilitated early leech use and provided for the psychological preparation of the patient, availability of leeches, and an antibiotic prophylaxis regimen. 3. The complications associated with leech use can be minimized with antibiotic therapy, wound care, and hematocrit monitoring. 4. The use of the medicinal leech for salvage of the venous-congested flap is a safe, efficacious, economical, and well-tolerated intervention.

The temporalis muscle flap for reconstruction after head and neck oncologic surgery.

OBJECTIVE: To explain the applications, technique, and potential complications of the temporalis muscle flap used for immediate or delayed reconstruction of head and neck oncologic defects. STUDY DESIGN: Fresh cadaver dissection and 5-year retrospective chart review. METHODS: A fresh cadaver dissection was performed to illustrate the surgical anatomy of the temporalis muscle flap with attention to specific techniques useful in avoiding donor site morbidity (facial nerve injury and temporal hollowing). A chart review was performed for 13 consecutive patients from the last 5 years who underwent temporalis muscle flap reconstruction after oncologic resection of the lateral and posterior pharyngeal wall, hard and soft palate, buccal space, retromolar trigone, and skull base. RESULTS: Patient follow-up ranged from 2 to 45 months. Nine patients had radiation therapy. There were no cases of flap loss. Resection of the zygomatic arch followed by wire fixation facilitates flap rotation and minimizes trauma to the flap during placement into the oropharynx. Preservation of the temporal fat pad attachment to the scalp flap decreases temporal hollowing and protects the facial nerve. Replacing the zygoma and preserving the anterior third of the temporalis muscle in situ further diminishes donor-site hollowing. CONCLUSIONS: Compared with other regional flaps, such as the pectoralis myocutaneous flap, the temporalis muscle flap is associated with low donor-site esthetic and functional morbidity and offers great flexibility in reconstruction. The temporalis muscle flap is a useful, reliable flap that belongs in the armamentarium of surgeons who are involved with reconstruction of head and neck tissue defects.

A cost-effective and rational surgical approach to patients with snoring, upper airway resistance syndrome, or obstructive sleep apnea syndrome.

The past decade has seen several innovations in the surgical techniques available for treatment of patients with sleep-disordered breathing. Outpatient techniques such as laser-assisted uvulopalatoplasty (LAUP) and more aggressive procedures designed to address hypopharyngeal and base of tongue obstruction (genioglossus advancement and hyoid myotomy) have been developed and proven successful. We describe the efficacy of LAUP for snoring (72.7%), upper airway resistance syndrome (81.8%), and mild (mean [+/-SD] respiratory disturbance index [RDI] = 12 +/- 8.1) obstructive sleep apnea (41.7%) in 56 patients who underwent 132 LAUP procedures in a 26-month period. Thirty-two patients with more significant obstructive sleep apnea (mean RDI = 41.8 +/- 23.1) underwent multilevel pharyngeal surgery consisting of genioglossus advancement and hyoid myotomy combined with uvulopalatopharyngoplasty. The surgical success rate in this group of patients was 85.7% when commonly accepted criteria were applied. We recommend a stratified surgical approach to patients with sleep-disordered breathing. Progressively worse airway obstruction marked by multilevel pharyngeal collapse and more severe sleep-disordered breathing is treated with incrementally more aggressive surgery addressing multiple areas of the upper airway.

Simultaneous treatment with BDNF and CNTF after peripheral nerve transection and repair enhances rate of functional recovery compared with BDNF treatment alone.

The objective was to investigate the effects of brain-derived neurotropic factor (BDNF) and ciliary neurotropic factor (CNTF) on peripheral nerve regeneration. Thirty Sprague-Dawley rats underwent left sciatic nerve transection and repair according to three experimental groups: epineurial coaptation (EC), EC with BDNF delivered by an osmotic pump (EC-BDNF), and EC with BDNF and CNTF delivered similarly (EC-BDNF/CNTF). Nerve regeneration was assessed using sciatic functional indices, quantitative histomorphology, and molecular analysis for proteins associated with nerve regeneration. Analysis of variance (ANOVA) comparing all groups at each time point demonstrated significant differences between groups on days 20, 30, 40, 50, 60, and 80. A paired, two-tailed Student's t-test with the Bonferroni correction for multiple comparisons demonstrated that at 40 days postoperatively, animals in the EC-BDNF/CNTF group (n = 7) manifested superior functional recovery compared with those in the EC group (n = 9) and those in the EC-BDNF group (n = 9) (P < 0.001 and P < 0.05, respectively). At 80 days, the animals in both the EC-BDNF (P < 0.01) and EC-BDNF/CNTF (P < 0.05) groups demonstrated greater functional recovery compared with those in the EC group, with no significant difference between the two factor groups at the endpoint. Morphometric analysis demonstrated that nerves from animals in the EC-BDNF/CNTF group had the largest mean axon diameters as compared with those from the EC (proximal: P < 0.001, distal: P < 0.05) and EC-BDNF (proximal: P < 0.01) groups. No significant differences were seen in nerve cross-sectional area. In distal nerve segments, Western blot analysis revealed that expression of myelin-associated glycoprotein was higher than control for the EC group and lower than control for both the EC-BDNF and EC-BDNF/CNTF groups. We conclude that BDNF/CNTF combined treatment increases the early rate of functional sciatic nerve regeneration over treatment with BDNF alone, although the degree of maximal recovery was similar at the conclusion of the experiment.

Recognition and surgical management of the upper airway resistance syndrome.

Patients with upper airway resistance syndrome (UARS) have clinical signs and symptoms of excessive daytime somnolence (EDS) in the absence of obstructive sleep apnea. These patients have increased upper airway resistance, reflected by an elevated intrathoracic pressure measurement, despite a normal respiratory disturbance index (RDI). Physical findings often include excessive palatal tissue and narrowing of the oropharynx and hypopharynx. Nine patients with UARS who received surgical treatment were prospectively evaluated. The four men and five women had signs of EDS, with or without snoring. The mean (+/- standard deviation) RDI was 2.1 (+/- 1.2), and the mean esophageal pressure recording during polysomnography was -36.7 (+/- 16.2) cm H2O. The Epworth sleepiness scale was used to quantify EDS. The preoperative score of 12.0 (+/- 6.6) decreased to 3.4 (+/- 1.9) (P = .001) after surgical treatment. A variety of procedures, all including some type of palatal surgery, were performed. No treatment complications occurred. The recognition of UARS and an understanding of the mechanisms responsible for the progressive development of obstructive sleep apnea syndrome may facilitate the prompt identification and treatment of such patients. The pathophysiology of UARS and a preliminary report of its surgical treatment are discussed.

Direct bonded orthodontic brackets for maxillomandibular fixation.

OBJECTIVES/HYPOTHESIS: Mandibular fracture treatment often includes arch bar maxillomandibular fixation (MMF), either alone or in combination with open reduction/internal fixation (ORIF) techniques. The glove perforation rate associated with arch bar placement, the incidence of blood-borne pathogen positivity in facial fracture patients, and the injurious effects of arch bars on dental enamel and gingiva have prompted the development of safer alternatives to arch bar MMF. This study evaluates the efficacy, ease of use, and safety profile of one such alternative: orthodontic direct bonded bracket fixation (MMF/DBB). STUDY DESIGN: Prospective study of consecutive mandible fracture patients treated with MMF/DBB. METHODS: Thirty-two patients with mandibular fractures were evaluated from January 1994 to July 1997. Fourteen were appropriate for treatment with MMF/DBB (12 men and two woman; mean age, 24.6+/-7.2 y; range, 16-42 y). Fracture sites included symphysis, angle, condylar neck, coronoid, and body. Nine patients underwent MMF/DBB alone; five underwent MMF/DBB with subsequent ORIF. RESULTS: No infection, malocclusion, malunion/nonunion, or enamel/ gingiva injury occurred. Mean follow-up was 6 months (range, 1-12 mo). Oral hygiene with MMF/DBB was superior to historical controls using arch bars. CONCLUSIONS: MMF/DBB can serve as the single treatment method with satisfactory results in patients with favorable, less complicated mandible fractures, although with increased experience, we have treated several more complex cases with MMF/DBB alone. In cases necessitating ORIF, MMF/DBB can be performed preoperatively to align fracture segments and reestablish occlusion. This facilitates placement of osteosynthesis plates and reduces ORIF operative time. MMF/DBB is an economical, safe technique that minimizes blood-borne-pathogen risk to the operative team, eliminates periodontal injury, facilitates postoperative dental hygiene, and is painless to apply and remove.

Brain-derived neurotrophic factor and collagen tubulization enhance functional recovery after peripheral nerve transection and repair.

OBJECTIVE: To investigate the effect of brain-derived neurotrophic factor (BDNF) and collagen tubulization (CT) on the regeneration of transected peripheral nerves. METHODS AND DESIGNS: The left sciatic nerve of 40 Sprague-Dawley rats was transected then repaired using one of four techniques; epineurial coaptation, CT, CT with BDNF delivered by an osmotic pump to the repair site, or CT with BDNF covalently cross-linked to the collagen matrix (CT/linked-BDNF). Sciatic functional indices were measured preoperatively at 10-day intervals for 90 days. Segments of the sciatic nerves proximal and distal to the repair site were harvested at 90 days for histologic and morphometric evaluation. RESULTS: Animals repaired by CT/linked-BDNF (n=10) demonstrated the most favorable functional recovery of all groups, with statistically significant differences seen compared with animals repaired by CT (n=10, P=.05) and epineural coaptation (n=9, P<.001). Animals repaired by CT with BDNF delivered by an osmotic pump (n=8) and CT also showed statistically superior functional recovery compared with those repaired by epineurial coaptation (P=.005 and P=.02, respectively). Nerves repaired by CT/linked-BDNF had the largest mean axon diameters proximal and distal to the repair site. CONCLUSION: Brain-derived neurotrophic factor and CT improve the rate and the degree to which recovery of sciatic function occurs after nerve transection and repair. Animals repaired by CT/BDNF-linked demonstrated the most favorable functional recovery of all groups. Animals whose repair technique included BDNF had the largest mean axon diameters of all groups.

Radiofrequency ablation of the nerve to the corrugator muscle for elimination of glabellar furrowing.

Glabellar furrows are caused by hyperdynamic activity of the corrugator supercilii muscles. A minimally invasive, percutaneous technique for eliminating glabellar furrows is described. An insulated, bipolar needle is inserted vertically through the eyebrow skin to entrap the corrugator nerve plexus. To confirm proper positioning, a stimulating current is delivered to the needle during observation of corrugator supercilii muscle response. Radiofrequency energy is then delivered to the needle, thereby ablating the intervening nerve tissue. This technique is in the early stage of optimization and is being evaluated in an ongoing Stanford University Human Subjects protocol, Stanford, Calif. The preliminary results are reported herein.

The validity of ex vivo laser skin treatment for histological analysis. A prospective controlled study.

BACKGROUND: Laser treatment of skin following removal from human subjects has been the staple of laser research. However, no study has been done to assess the efficacy of ex vivo skin for predicting the behavior of laser treatments in living human tissue. OBJECTIVE: To assess the validity of the ex vivo model by comparing histological characteristics of skin treated with laser prior to and following its removal in rhytidectomy. STUDY DESIGN: Nonrandomized controlled intervention study in which each patient served as both experimental subject and control for different skin sites. PATIENTS: Ten patients with actinic skin changes. INTERVENTIONS: Patients underwent laser treatment to 4 left preauricular sites 1 hour prior to rhytidectomy as follows: carbon dioxide laser treatment alone, carbon dioxide laser treatment followed by erbium:YAG laser treatment, erbium:YAG laser treatment alone, and erbium:YAG laser treatment followed by carbon dioxide laser treatment. The skin was examined by a dermatopathologist blinded to the identity of each specimen. Untreated skin was also removed and immediately subjected to laser treatment identical to that employed in the in vivo skin. This skin was examined histologically. MAIN OUTCOME MEASURES: Regularity of ablation, depth of the necrotic zone, amount of skin removed, degree of collagen injury, and degree of inflammation. RESULTS: There were significant differences between the ex vivo and in vivo groups. The ex vivo specimens demonstrated more than 10 times the irregularity of ablation of the in vivo specimens (irregularity index of 3.0 for the ex vivo group vs 0.25 for the in vivo specimens; P < .05). The incidence of collagen injury was slightly lower for the ex vivo group (1.0 vs 1.3), as was the degree of inflammation (1.4 vs 1.5). The greatest differences were the significantly smaller necrotic zone in the ex vivo specimens (51 vs 71 microns) and the smaller amount of skin removed (118 vs 234 microns). These findings were consistent for all 4 laser treatment regimens studied. CONCLUSIONS: Significant differences were found between the in vivo and ex vivo models. Irregularity of ablation in the ex vivo specimens was 10 times that in the living specimens, limiting histological accuracy in the ex vivo model. The ex vivo skin model underestimated the amount of tissue ablation. This suggests that an in vivo model should be adopted as the standard for laser research.

Temperature-controlled radiofrequency energy delivery for gastroesophageal reflux disease: the Stretta procedure.

BACKGROUND: The delivery of temperature-controlled radiofrequency (RF) energy has been utilized effectively for the treatment of benign prostatic hyperplasia, sleep-disordered breathing, joint laxity, tumors, and cardiac dysrhythmias. The mechanism of action of RF delivery, depending on the specific disease pathophysiology, is related to wound contraction/remodeling or nerve pathway ablation. More recently, temperature-controlled RF energy delivery has been applied for the treatment of gastroesophageal reflux disease (GERD). PURPOSE: To review the use of temperature-controlled RF energy in clinical applications, specifically the safety and efficacy data regarding endoluminal delivery of RF energy for the treatment of GERD (Stretta procedure). RESULTS: Endoluminal RF energy delivery to the gastroesophageal junction for the treatment of GERD is performed using conscious sedation on an outpatient basis. After treatment, medication use is significantly reduced or eliminated at 6 and 12 months, and there is a significant reduction in both the distal and proximal esophageal acid exposure on 24-hour ambulatory pH testing. All studies reviewed demonstrate improvement in GERD symptom scores, heartburn, satisfaction, and quality of life after treatment. There have been no cases of achalasia or stricture resulting from this procedure. Data support both an augmentation of the physical barrier function of the gastroesophageal junction and a reduction in triggering of transient LES relaxations as plausible mechanisms of action for this procedure. CONCLUSION: Endoluminal RF energy delivery has been shown in several studies to be safe and effective for the treatment of GERD and is a promising new technology for this chronic disorder.

Functional recovery following nerve injury and repair by silicon tubulization: comparison of laminin-fibronectin, dialyzed plasma, collagen gel, and phosphate buffered solution.

PURPOSE: This study was designed to investigate the potential for enhancement of peripheral nerve regeneration by the manipulation of the neural microenvironment with laminin-fibronectin solution (LF), dialyzed plasma (DP), collagen gel (CG), or phosphate buffered saline (PBS) in a silicon tubulization repair model. METHOD: A rat sciatic nerve model of injury and repair was used to study the effects of exogenous matrix precursors (contained in LF or DP), CG or PBS on nerve regeneration. A total of 50 Sprague-Dawley rats underwent left sciatic nerve transection and repair by silicon tubulization. The silicon tubules were either left empty (E), or filled with solutions of LF, DP, CG, or PBS. Nerve function was assessed preoperatively and then postoperatively, every 10 days for 90 days using sciatic functional indexes (SFI). On postoperative day 90, the sciatic nerves were harvested for histologic analysis and the posterior compartment muscles of each animal were harvested and weighed. Molecular analysis for two proteins associated with neural regeneration was performed on the nerve segments. RESULTS: All five animal groups demonstrated equivalent functional recovery. Comparison of the rate of recovery and mean maximal recovery between each group revealed no statistically significant differences, with P-values ranging from 0.30 to 0.95. Posterior compartment muscle masses were similar in all groups except for LF, whose animals had muscle masses 8-9% lower than CG, PBS, or E (P < 0.05). CONCLUSION: Alteration of the regenerating neural microenvironment with exogenous matrix precursors (LF, DP), CG or PBS failed to improve sciatic functional recovery after nerve transection and silicon tubulization in this model. From this study, we conclude that LF, DP, CG, and PBS do not enhance the rate or degree of recovery of peripheral nerve function across a narrow gap when nerves are repaired by silicon tubulization.

Analysis of formulations containing pralidoxime mesylate by liquid chromatography.

An improved liquid chromatography procedure has been devised for the analysis of pralidoxime mesylate (P2S) and its degradation products in solution. An additional degradation product, 2-hydroxyaminoiminomethyl-1-methylpyridinium, has been positively identified and its route of formation and that of another recently identified product, 2-hydroxymethyl-1-methylpyridinium, has been established. Previous problems with the chromatography of 2-formyl-1-methylpyridinium have been resolved and the new method will resolve P2S and eight of its degradation products.

Simultaneous determination of hydroxylamine and cyanide in formulations containing pralidoxime salts by flow injection.

A flow injection method is described for the simultaneous determination of cyanide and hydroxylamine which are known decomposition products of formulations containing pralidoxime salts used in the treatment of anticholinesterase poisoning. By using the diffusion of HCN from the carrier stream followed by amperometric detection, high selectivity and sensitivity and a wide dynamic range can be achieved. Hydroxylamine is determined by its oxidation with iodine to nitrite which can then be determined colorimetrically. The gas diffusion unit effectively acts as a stream splitter for the two analytes allowing their simultaneous determination from a single sample injection. The performance of the system and its applicability to thermally stressed pralidoxime solutions are described.

Total testosterone, free-androgen index, calculated free testosterone, and free testosterone by analog RIA compared in hirsute women and in otherwise-normal women with altered binding of sex-hormone-binding globulin.

We compared the clinical value of information on free testosterone as measured with the Coat-A-Count (Diagnostic Products Corp.) radioimmunoassay kit involving a ligand analog with that of total testosterone, the free-androgen index, and free testosterone calculated from concentrations of testosterone, sex-hormone-binding globulin, and albumin, in hirsute women, pregnant women, oral-contraceptive users, women with thyroid disease, and epileptic women taking phenytoin. Total testosterone, the free-androgen index, calculated free testosterone, and free testosterone by RIA were increased in 41-68% of hirsute women. Values for free testosterone increased in the first and third trimesters of pregnancy but remained within normal limits in all non-hirsute groups. Total testosterone was increased in patients having increased sex-hormone-binding globulin, whereas the free-androgen index and, to a lesser extent, calculated free testosterone were significantly decreased. Free testosterone measured by analog RIA not only has greater diagnostic efficiency than total testosterone, it also is technically simpler to determine than the free-androgen index and calculated free testosterone.

The role of precision in determining the performance of a thyrotropin assay in diagnosing hyperthyroidism.

We examined the relationship between analytical sensitivity, precision at the lower limit of the reference interval, and diagnostic performance in hyperthyroidism for one radioimmunoassay and five immunometric assay kits for thyrotropin. The analytical sensitivity of these kits extended from 0.05 to 1.56 milli-int. units/L. Diagnostic efficiencies of the immunometric assays, in discriminating between euthyroidism and hyperthyroidism, ranged between 93% and 98%. There was a highly significant correlation (r = 0.99, P less than 0.001) between analytical sensitivity and diagnostic efficiency. The between-assay coefficients of variations, at the lower limit of the reference interval, ranged from 26% to 87%. There was no correlation (r = 0.36) between precision, at this concentration, and diagnostic efficiency. We conclude that analytical sensitivity and not precision is the major determinant in controlling the diagnostic performance of a thyrotropin assay in hyperthyroidism.

Histologic analysis of the thermal effect on epidermal and dermal structures following treatment with the superpulsed CO2 laser and the erbium: YAG laser: an in vivo study.

BACKGROUND AND OBJECTIVE: To compare the in vivo histologic effects of the carbon dioxide (CO2) and erbium:yttrium aluminum garnet (Er:YAG) lasers. To ascertain the effects of combining CO2 and Er:YAG laser modalities during a single treatment session. STUDY DESIGN/MATERIALS AND METHODS: Ten patients underwent laser treatment to four left preauricular sites 7 days prior to rhytidectomy as follows: CO2 alone, CO2/Er:YAG, Er:YAG alone, and Er:YAG/CO2. The right preauricular area was identically treated 1 hour prior to rhytidectomy. Laser treated skin was excised during rhytidectomy and was evaluated histopathologically in a blinded manner. RESULTS: After 7 days, all groups were reepithelialized and showed equal neo-collagen formation. After 7 days, CO2/Er:YAG and Er:YAG alone had the least collagen injury and thickest epidermis and papillary dermis of all groups. Specimens lased 1 hour prior to excision showed the least collagen injury and thermal necrosis when treated with CO2/Er:YAG and Er:YAG alone. Four passes with CO2 removed 250 microm of tissue, while eight passes with the Er:YAG removed 160 microm of tissue. CONCLUSIONS: Limiting CO2 laser passes and ending with Er:YAG produces less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration. CO2 followed by Er:YAG has similar thermal necrosis and collagen injury as Er:YAG alone, presumably due to Er:YAG removal of CO2 induced thermal injury.

Augmentation of lower esophageal sphincter pressure and gastric yield pressure after radiofrequency energy delivery to the gastroesophageal junction: a porcine model.

BACKGROUND: An endoscopic technique that eliminates gastroesophageal reflux disease would be of benefit to patients. The endoscopic delivery of radiofrequency energy to the porcine gastroesophageal junction was investigated and its effect on lower esophageal sphincter pressure, gastric yield pressure, and histology was assessed. METHODS: Twenty pigs underwent esophageal manometry and endoscopic injection of botulinum toxin (100 units) into the lower esophageal sphincter. After 1 week, animals were randomized to radiofrequency energy treatment of the gastroesophageal junction with a 4- needle catheter and thermocouple-controlled generator (n = 13) or no further intervention (control, n = 7). At 9 weeks, animals underwent esophagoscopy, manometry, gastric yield pressure determination, and sacrifice for histopathologic evaluation. RESULTS: Mean lower esophageal sphincter pressure declined by 3.7 +/- 2.6 mm Hg (control, p = 0.03) vs. 0.97 +/- 5.8 mm Hg (radiofrequency, p = 0.29) after 9 weeks. Mean gastric yield pressure was 24.9 +/- 8.2 mm Hg (control), compared with 43.4 +/- 10. 7 mm Hg (radiofrequency) (p = 0.0007). Histopathologic assessment demonstrated normal mucosa, mild fibrosis, and no inflammation. CONCLUSIONS: Radiofrequency energy delivery reversed much of the lower esophageal sphincter pressure reduction achieved with botulinum toxin injection and augmented gastric yield pressure by 75% compared with controls. Given the safety of radiofrequency energy delivery in this study and in other areas of medicine, human studies to assess the effect of radiofrequency energy on gastroesophageal reflux disease are warranted.