Biomedical subjects

L Reinisch

Publications and source records attributed to L Reinisch.

At least 37 records · Page 2Linked to original sources

PubMed1999

Histologic and physiologic effects of electrocautery, CO2 laser, and radiofrequency injury in the porcine soft palate.

OBJECTIVES: This study was undertaken to compare the effects of electrosurgery, CO2 laser, and radiofrequency on the histological structure and physiological properties of the soft palate. These surgical techniques are used for stiffening and reducing the soft palate in the treatment of snoring and mild sleep apnea. STUDY DESIGN: Fifteen pigs were divided into five groups. METHODS: group 1 underwent electrosurgery incision of the lateral soft palate and excision of the uvula. Group 2 underwent the same procedure with the CO2 laser. Group 3 underwent CO2 laser ablation of the midline soft palate mucosa. Group 4 underwent radiofrequency volumetric reduction. Group 5 served as control. After 5 weeks the animals were sacrificed. Soft palate mucosa and muscle were subjected to tensiometric and histological analysis. Statistical analysis of tensiometric measurements was done with an ANOVA using a Bonferroni-Dunn correction. RESULTS: Tensiometric measurements of the mucosa were increased over normal controls when the surgical technique resulted in mucosal disruption. When the surgical technique resulted in primarily muscle disruption (radiofrequency) tensiometric measurements of the muscle were increased over controls. Histological analysis demonstrated normal remucosalization in all specimens, with fibrosis increased at the site of the primary injury. CONCLUSIONS: The type of injury produced resulted in identifiable patterns of physiological and histological change. Understanding of the effects of available surgical techniques is important in guiding our choice of surgical approach and allows us to better counsel our patients on their surgical options.

Animals↗

PubMed1999

Radiofrequency tissue ablation of the inferior turbinates using a thermocouple feedback electrode.

OBJECTIVE: The objective of this clinical trial was to assess the safety and efficacy of radiofrequency (RF) tissue ablation of the inferior turbinates in the treatment of nasal obstruction using an RF energy delivery system with a thermocouple feedback electrode. METHODS: A prospective, nonrandomized study of 11 patients (mean age, 47+/-12 y) with chronic nasal obstruction was conducted. Using patient-based visual analogue scales (VAS), symptom parameters were assessed. These included degree of nasal obstruction, frequency of nasal obstruction, and pain. Physician assessment of nasal obstruction was also collected by the principal investigator. Follow-up was conducted at 24 hours, 1 week, 4 weeks, 8 weeks, and 1 year. ANOVA was carried out to determine statistically significant differences in the data. Data were fit to a regression model, and confidence intervals were determined from a 95% confidence level. RESULTS: In patient-assessed degree of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.001, P<.0001, and P<.0008, respectively). There was no difference between 8 weeks and 1 year (P<.15). The data appeared to follow an exponential decay to a constant value. The pretreatment baseline average degree of obstruction was 7.5+/-0.5 on a scale of 0 to 10. The degree of obstruction after 8 weeks was 2.7+/-0.6. The time constant for this change was 21 days to reach 90% of the final value. At 1 year, degree of obstruction was 3.3+/-0.7. For frequency of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.0001, P<.0001, and P<.0001, respectively). There was no difference between 8 weeks and 1 year (P<.15). The pretreatment baseline average frequency of obstruction was 7.8+/-0.5. The remaining frequency of obstruction after 8 weeks was 2.9+/-0.6. The time constant was 18 days. At 1 year, frequency of obstruction was 3.3+/-0.6. Physician assessment of nasal obstruction revealed statistical significance among baseline and 4 weeks, and baseline and 8 weeks (P<.0055 and P<.0056, respectively). There was no difference between 4 weeks and 8 weeks (P<.24). The average initial obstruction was 83%+/-4%. The remaining obstruction after 8 weeks was 58% +/-5%. The time constant was 14 days. Mild pain was reported by 55% of patients during the procedure; the remaining 45% reported no pain. Only one patient required pain medication consisting of acetaminophen after the procedure. There were no significant complications. CONCLUSIONS: Degree and frequency of nasal obstruction, as reported by patients, decreased following RF tissue ablation of the inferior turbinates. This improvement in symptoms was still evident after 1 year (P<.001). Physician assessment of obstruction also correlated with patient reports for the initial 8-week study period. The procedure was safe and well tolerated. Thermocouples within the active electrode provided additional feedback to the operating surgeon allowing the use of relatively lower tissue temperatures, power, and energy as compared with traditional techniques. These results support the need for continued research to evaluate this modality as a treatment for chronic nasal obstruction.

Adult↗

PubMed1999

Ablation of Teflon granulomas in the canine larynx with the free-electron laser.

This study develops a canine model for the treatment of laryngeal Teflon granulomas and demonstrates endoscopic ablation using the free-electron laser (FEL) set at a wavelength of 8.5 microm. Laryngeal Teflon granulomas may cause dysphonia and airway obstruction, and they are difficult to remove. The infrared absorption spectrum of Teflon reveals a strong absorption peak centered at 8.5 microm. In this study, 12 dogs had the right vocal cord injected with Teflon paste. Two months later, Teflon granuloma formation was confirmed histologically. Laser incisions into the granulomas were performed at 3 different wavelengths: 7.4 microm (FEL), 8.5 microm (FEL), and 10.6 microm (carbon dioxide laser). Histopathologic analysis was performed at 1 week and 6 weeks after the laser incisions. The FEL at the 8.5-microm wavelength was found to optimally ablate the Teflon granulomas, but the granulomas persisted in the specimens treated with 7.4 microm (FEL) and 10.6 microm (carbon dioxide laser).

Animals↗

PubMed1999

Histomorphometric and laryngeal videostroboscopic analysis of the effects of corticosteroids on microflap healing in the dog larynx.

The histologic and functional effects of unilateral, layered corticosteroids on lateral microflap healing in 15 dogs were analyzed. Histologic sections of steroid-treated vocal folds (VFs) were studied with computer morphometry to examine differences in the tissue healing response. Paired analysis revealed increases in the inflammatory infiltrate around the microflap in the steroid-treated VFs at 2, 4, and 6 weeks (6.3%, 30.6%, and 34.9%, all with p < .02). The neovascular response in the steroid-treated VFs was less at 2 weeks (-20.9%, p < .005) but greater at 4 and 6 weeks (16.3% and 4.3%, p < .005). To better characterize the effect of steroids on the healing process, a normal, time-dependent distribution was applied to the histologic data and demonstrated a delay in the steroid-treated VF tissue response of 12 days for the inflammatory infiltrate and 21 days for the neovascular response. Qualitative and quantitative analysis of in vivo laryngeal videostroboscopy (LVS) samples taken preoperatively and at sacrifice could not identify significant differences in appearance, amplitude, mucosal wave, or suppleness between the 2 VFs. Therefore, although corticosteroids cause a delay in wound healing, LVS does not discern differences in microflap characteristics between healing steroid-treated and control VFs at 2, 4, or 6 weeks. If steroids are used, the surgeon should account for a probable delay in wound healing, but should not expect an overall difference in functional outcome.

Administration, Topical↗

PubMed1999

Inhibition of subglottic stenosis with mitomycin-C in the canine model.

The objective of this randomized, prospective study was to study the efficacy of topical mitomycin-C in the inhibition of subglottic stenosis in a canine model. Subglottic stenosis was elicited with the carbon dioxide laser in 10 mongrel dogs. Radial incision and serial dilation of the subglottic airway were then carried out. The animals were randomized to receive a topical solution of 1% mitomycin-C to the dilated area for a 5-minute duration or no further treatment. Weekly direct microlaryngoscopy and photodocumentation were performed during the 6-week study. Airway distress developed in 4 of the 5 control dogs, requiring early sacrifice, while all treatment group animals survived the duration of the study (p < or = .006). Morphometric analysis of the subglottic photographs confirmed a greater than 100% increase in the percentage of relative airway at sacrifice in the treatment group (p < or = .049). A statistically significant (p < or = .015) decrease in collagen formation in the subglottic scar of dogs treated with topical mitomycin-C was documented. Mitomycin-C favorably altered the clinical progression of subglottic stenosis, improved quantified airway patency, and reduced the amount of subglottic collagen formation in the canine model.

Administration, Topical↗

PubMed1999

Effective laser ablation of bone based on the absorption characteristics of water and proteins.

BACKGROUND: Collateral thermal damage and residual char formation have severely limited the use of conventional lasers in the surgical preparation of bony tissue. Thermal damage from lasers can be minimized by selecting a wavelength that is strongly absorbed and by reducing the laser pulse duration. In contrast to the fixed wavelengths and microsecond pulse intervals of conventional lasers, the Vanderbilt free electron laser (FEL) can be set at wavelengths ranging from 2.1 to 9.8 microm, and the pulse duration can be reduced to a series of 1 to 2 picosecond (ps) micropulses delivered in succession over intervals of 4 microsecond macropulses. The purpose of this study was to compare the morphologic and chemical changes induced in the near-surface region of bone following exposure to the FEL at 3.0, 6.1, and 6.45 microm wavelengths. The selected wavelengths coincide with the vibrational modes of proteins and water within bone. METHODS: Under general anesthesia, laser incisions were made in the tibias of 14 skeletally mature rabbits. Laser parameters included 22.5+/-2.5 mJ/pulse delivered in individual 4 microsecond macropulses at a repetition rate of 30 Hz, focused to 200 microm and 500 microm spot sizes. Laser incisions were made using a computer-assisted surgical program, and control incisions were created with a bone saw. Rabbits were euthanized after the final incision, tibias recovered, and non-decalcified specimens processed for light microscopy. Separate samples were prepared for FTIR (Fourier transform infrared) photoacoustic spectroscopic analysis. RESULTS: The light microscopy sections of the ablation defects created at the differing wavelengths showed similar features, i.e., 2 zones of collateral damage, a zone generally < 10 mm of extensive thermal damage, and a wider zone of empty lacunae. In comparing treated and untreated surfaces, the spectral differences were limited to a relative decrease in intensity of the amide II and III absorption peaks in all laser-treated surfaces. CONCLUSIONS: Spectroscopic and histologic results indicated minimal thermal damage to bone ablated at 3.0, 6.1, and 6.45 microm wavelengths using the FEL (Fourier transform infrared) at the specified parameters. The FTIR photoacoustic spectroscopic results suggest that the char layer is limited to an area less than approximately 6 microm from the surface.

Absorption↗

PubMed1998

Optimizing fluence and debridement effects on cutaneous resurfacing carbon dioxide laser surgery.

OBJECTIVE: To develop methods to compare carbon dioxide (CO2) resurfacing lasers, fluence, and debridement effects on tissue shrinkage and histological thermal denaturation. DESIGN: In vitro human or in vivo porcine skin samples received up to 5 passes with scanner or short-pulsed CO2 resurfacing lasers. Fluences ranging from 2.19 to 17.58 J/cm2 (scanner) and 1.11 to 5.56 J/cm2 (short pulsed) were used to determine each laser's threshold energy for clinical effect. Variable amounts of debridement were also studied. MAIN OUTCOME MEASURES: Tissue shrinkage was evaluated by using digital photography to measure linear distance change of the treated tissue. Tissue histological studies were evaluated using quantitative computer image analysis. RESULTS: Fluence-independent in vitro tissue shrinkage was seen with the scanned and short-pulsed lasers above threshold fluence levels of 5.9 and 2.5 J/cm2, respectively. Histologically, fluence-independent thermal depths of damage of 77 microns (scanner) and 25 microns (pulsed) were observed. Aggressive debridement of the tissue increased the shrinkage per pass of the laser, and decreased the fluence required for the threshold effect. In vivo experiments confirmed the in vitro results, although the in vivo threshold fluence level was slightly higher and the shrinkage obtained was slightly lower per pass. CONCLUSIONS: Our methods allow comparison of different resurfacing lasers' acute effects. We found equivalent laser tissue effects using lower fluences than those currently accepted clinically. This suggests that the morbidity associated with CO2 laser resurfacing may be minimized by lowering levels of tissue input energy and controlling for tissue debridement.

Animals↗

PubMed1998

Interstitial Nd:YAG photocoagulation for vascular malformations and hemangiomas in childhood.

BACKGROUND: Vascular malformations and cavernous hemangiomas are common in childhood. Although cavernous hemangiomas may resolve spontaneously, aggressive intervention is required when their growth could damage vital adjacent structures, such as the orbit, nose, or tongue. OBJECTIVE: To evaluate the efficacy of interstitial Nd:YAG photocoagulation as an adjunct to intralesional and systemic corticosteroids for treatment of hemangiomas and vascular malformations that had failed to respond to other therapies. DESIGN: Prospective, nonrandomized trial. SETTING: Two referral practices of facial plastic and reconstructive surgery in tertiary care, academic medical centers. PATIENTS: Ten consecutive pediatric patients with either hemangioma or vascular malformation of the head and neck. INTERVENTION: Laser photocoagulation with an interstitial technique. The Nd:YAG fiber was introduced into the lesion via a 14-gauge angiocatheter needle, and the laser fiber was advanced as coagulation proceeded within the tissue. MAIN OUTCOME MEASURES: Decrease in the area of the target lesion, amount of energy applied, and number of treatments required to achieve reduction in size. RESULTS: Long-term follow-up demonstrated regression of the lesion in all 10 patients with good cosmetic results. The range of reduction in size was 20% to 98%. No reexpansion of the lesions was noted after a mean follow-up of 13 months. CONCLUSIONS: Interstitial photocoagulation of hemangiomas and vascular malformations is an effective treatment for carefully selected patients. When properly applied, this technique can achieve reduction in the size of these lesions without compromising cosmesis.

Adolescent↗

PubMed1998

Erythema after cutaneous laser resurfacing using a porcine model.

OBJECTIVES: To measure and compare postoperative erythema after laser cutaneous resurfacing using 2 carbon dioxide laser systems and varying postoperative treatment methods. DESIGN: Carbon dioxide laser systems are used as cutaneous resurfacing tools. The continuous-wave lasers have been associated with postoperative erythema, but the short-pulsed lasers reportedly result in less postoperative erythema because of shorter pulse durations. Although subjective evaluations of results have been published, a side-by-side comparison with digital photography has not been performed. Furthermore, postoperative treatment varies among physicians, and objective data about this treatment are scarce. SUBJECTS: To compare postoperative erythema, we created 240 resurfacing wounds on 8 piglets with continuous-wave and short-pulsed lasers, using the manufacturers' suggested settings. By using photography and computed color analysis, we measured the resultant erythema after 1, 3, and 5 laser passes at days 0, 1, 3, 5, 7, and 14. Tissue samples were obtained for histological analysis on days 0, 3, 7, and 14. INTERVENTION: We compared the resolution of erythema after postoperative treatment with petroleum jelly (Vaseline), a wound dressing (Vigilon), partially hydrogenated vegetable oil (Crisco), or a combination drug, bacitracin zinc-neomycin sulfate-polymyxin B sulfate on the wounds. RESULTS: The short-pulsed carbon dioxide laser resulted in an average of 22% less erythema compared with the continuous-wave laser (P<.001). No statistically significant difference in erythema was found among the postoperative treatment methods (P>.10). CONCLUSIONS: Compared with the continuous-wave laser, the short-pulsed carbon dioxide laser results in less postoperative erythema. However, the type of postoperative treatment has little, if any, beneficial effect for reducing erythema.

Animals↗

PubMed1998

Collagen thermal damage and collagen synthesis after cutaneous laser resurfacing.

BACKGROUND AND OBJECTIVE: Objectively measure and compare postoperative collagen thermal damage and subsequent new collagen synthesis after cutaneous laser resurfacing using two carbon dioxide laser systems. STUDY DESIGN/MATERIALS AND METHODS: We created 240 resurfacing wounds on eight piglets with scanned and short-pulsed lasers using the manufacturer's suggested settings. The wounds varied with respect to the number of laser passes and postoperative survival times. Samples were harvested for histological analysis. RESULTS: The scanned laser resulted in an average of 52% more collagen thermal damage on the day of surgery (P < 0.0001) and an average of 78% more thermal damage 3 days postoperative (P < 0.0001) than the short-pulsed laser. The amount of new collagen synthesis correlated with the amount of thermal damage, with the scanned laser wounds showing 44% greater new collagen synthesis than the short-pulsed laser wounds on postoperative day 7 (P < 0.0001) and 48% greater new collagen synthesis on postoperative day 14 (P < 0.0001). CONCLUSION: Compared to the short-pulsed laser, the scanned laser results in a greater depth of collagen thermal damage with a correspondingly greater depth of new collagen synthesis after cutaneous resurfacing.

Animals↗

PubMed1998

Laser treatment of solar elastosis with epithelial preservation.

BACKGROUND AND OBJECTIVE: Laser resurfacing has gained wide acceptance for the treatment of actinic facial skin. However, postoperative care of the face is reasonably complicated and prolonged erythema is common. To simplify the postoperative care and to possibly reduce the duration of the erythema, we investigated a laser treatment that spares the epithelium. STUDY DESIGN/MATERIALS AND METHODS: A 980 nm diode laser was used with a spherical optic handpiece to focus the light in the dermis. We treated in vitro breast and facial skin and measured the tissue shrinkage and the histological changes. We also treated two patients and harvested the tissue after 6 and 21 days of wound healing. RESULTS: The diode laser treatment does not ablate the epidermis. The tissue shows shrinkage (16% at 8W) similar to three passes of the scanned carbon dioxide laser treatment (15%). Thermal damage in the dermis is similar to the residual damage left after laser resurfacing with the scanned carbon dioxide laser. After 21 days the tissue shows new collagen and an abundance of young elastin fibers. CONCLUSIONS: These investigations indicate that solar elastosis in skin can be treated with the 980 nm diode laser while preserving the epithelial layer.

Carbon Dioxide↗

PubMed1998

Histologic study of oral mucosa wound healing: a comparison of a 6.0- to 6.8-micrometer pulsed laser and a carbon dioxide laser.

Incisional wound healing in the canine oral mucosa was histologically monitored at 3, 7, and 14 days after incision. Healing was compared from a scalpel, a carbon dioxide (CO2) laser at 10.6 microm, and the Vanderbilt free-electron laser tuned to 6.0, 6.45, and 6.8 microm. A significant delay in wound healing was observed when incisions were made with the CO2 laser, probably attributable to the excess thermal damage caused by the continuous-wave laser beam. When using the short pulsed, free-electron laser, a much smaller delay comparable to the scalpel wound healing was observed. This smaller delay tended to decrease with increasing tissue absorption. The results emphasize the greater importance of laser pulse duration rather than wavelength in relation to the subsequent wound healing.

Absorption↗

PubMed1998

Effect of pulse duration on wound healing using a CO2 laser.

The authors investigated wound healing of incisions in the buccal mucosa of a canine model created using a CO2 laser with a short pulse structure (60 micros, 100 micros, and 120 micros) rather than a conventional continuous wave structure in a shuttered mode. The tissue from 10 animals was evaluated histologically and with tensiometry acutely and at postoperative days 3, 7, and 14. A Bonferroni-Dunn corrected ANOVA analysis at a 95% significance level was used to compare the effect of pulse duration on histologic morphology and wound tensile strength. The data indicate that shorter laser pulse durations create less lateral thermal injury (P < .009) and wounds with greater tensile strength (P < .005), resulting in earlier wound healing. The results also show that heat, sufficient to damage tissue, was conducted to adjacent tissue during laser pulses of 100 micros and longer. These results demonstrate that surgical CO2 lasers with a short pulse structure of approximately 60 micros or less could offer more prompt wound healing while maintaining the advantages of a 10.6-microm wavelength laser.

Animals↗

PubMed1998

Laryngotracheal reconstruction in the adult: a ten year experience.

The purpose of this study is to retrospectively analyze our experience with airway reconstruction, to outline a new staging system for laryngotracheal (LT) stenosis, and to identify preoperatively those patients likely to fail reconstruction. We reviewed 41 patients who underwent 46 LT reconstructions over the past 10 years. Success was judged by the ability to decannulate patients within 1 year postoperatively. Of our patients, 63% were treated successfully, and an additional 17% had intermediate success. The techniques used for laryngotracheoplasty with augmentation grafting and tracheal resection are reviewed. Major complications, thoracic complications, and wound complications are presented. Each patient was staged by the McCaffrey staging system and Cotton grades. We propose a new staging system based on the extent of the stenosis throughout the glottis, subglottis, and trachea. It is logical and easy to use. Applied to our cases of LT stenosis retrospectively, the new system predicts clinical success (chi2, p = .05). Using contingency tables and chi2 testing for statistical evaluation, we found that diabetics have a significantly higher failure rate (chi2, p = .0002). Further, we identified a group of patients who in addition to the airway stenosis also had comorbid medical conditions that frequently necessitate a tracheostomy. These patients have a significantly higher failure rate (chi2, p = .009). Using this information and applying the staging system prior to reconstruction, we can identify patients likely to fail.

Adolescent↗

PubMed1998

Ablation of teflon granuloma with the free-electron laser emitting in the eight- to nine-micron range.

In this study, we developed a rat model for Teflon granuloma and used this model to evaluate the removal of the granuloma at laser wavelengths at which Teflon has a maximal absorption. Twenty-four Teflon granulomas were created in 12 rats, and the gross and histologic effects from laser incision at four different wavelengths (8.25, 8.5, 8.75, and 10.6 microm) were evaluated acutely and at 7 and 14 days postoperatively. Polytetrafluoroethylene, or Teflon, is a relatively inert substance that has been used over the past 4 decades for endoscopic injection into the thyroarytenoid muscle of the larynx for the purposes of laryngeal rehabilitation in cases of unilateral vocal fold paralysis or incomplete glottic closure. In certain cases in which formation of granulomatous reaction to the Teflon occurs, patients may have significant dysphonia or airway compromise. Once Teflon has infiltrated the surrounding tissue planes, it is exceedingly difficult to remove endoscopically. Endoscopic removal of this granuloma is usually attempted with the carbon dioxide (CO2) laser and has had limited success. Examination of the infrared absorption spectrum of polytetrafluoroethylene reveals strong absorption in the mid-infrared region in the 8- to 9-microm range, with minimal absorption at 10.6 microm. Therefore, this absorption spectrum predicts a more efficient vaporization of Teflon at wavelengths near 8.5 microm. Using the free-electron laser to generate 8.25-, 8.5-, and 8.75-microm laser light, we found Teflon granuloma ablation was far superior to CO2 laser ablation at 10.6 microm. The 8.25-, 8.5-, and 8.75-microm wavelengths selectively ablated Teflon granuloma with minimal to no collateral thermal injury to tissue. The differences in thermal effects observed while actually using the lasers were confirmed histologically.

Animals↗

PubMed1998

Lateral laryngotomy for the removal of Teflon granuloma.

Teflon injection has been used for vocal fold medialization following paralysis. Recently, numerous articles have discussed the complications of Teflon injection, including overinjection, airway obstruction. Teflon granuloma, and an abnormal mass effect creating a decreased vibratory character of the true vocal fold. Multiple techniques for Teflon removal have been described. This report details our experience with complete Teflon granuloma removal via a lateral laryngotomy under local anesthesia. Microscopic dissection of the entire granuloma and the paraglottic space was accomplished in all patients. Due to extensive destruction caused by the granuloma, the vocal ligament was resected in 3 patients; it was partially resected and reanastomosed in 1 case, and spared in 6 patients. Laryngeal reconstruction was accomplished with an inferiorly based sternohyoid muscle rotation flap and arytenoid adduction. Effortful speech secondary to pressed vocal quality resolved in all patients. Near-normal to normal vocal quality was obtained in 4 patients, with the average "voice desirability" improving 60% and the effective glottic width increasing 29%. Factors that contributed to a successful outcome included noninvolvement of the vocal ligament and sparing of the mucosal cover.

Adult↗

PubMed1997

Healing of laser incisions in rat dermis: comparisons of the carbon dioxide laser under manual and computer control and the scalpel.

BACKGROUND AND OBJECTIVE: The Computer-Assisted Surgical Techniques (CAST) program was researched to decrease lateral tissue damage and improve wound healing subsequent to laser incision. CAST differs from the traditional laser because it makes the incision in a discontinuous manner, allowing tissue to cool during the incision process. STUDY DESIGN/MATERIAL AND METHODS: The transient temperature changes in the tissue adjacent to the incision were measured with a thermocouple in a rat model. The subsequent wound healing was studied with histology and tensiometry. RESULTS: The thermal measurements demonstrated that all CAST settings were cooler than the continuous mode of laser incision. However, histology and tensiometric studies showed mixed results. CONCLUSION: This research demonstrates that CAST can be used in future surgical applications with no delay in wound healing as compared to the manually controlled laser. However, this study also finds no decrease in the wound healing time when using the CAST program.

Animals↗

PubMed1997

Precise laser incisions, corrected for patient respiration with an intelligent aiming system.

BACKGROUND AND OBJECTIVE: Patient motion due to respiration and blood flow can negatively affect the precision of a laser incision. STUDY DESIGN/MATERIALS AND METHODS: The video image of the surgical field is monitored by a computer system, and trends in the motion are "learned" by the computer. The laser beam is then adjusted to compensate for predicted motion. Occasional erratic motion sometime causes a false prediction. In this event, the prediction is corrected with real-time feedback. RESULTS: Our experience shows that even with occasional false predictions, the motion compensation still gives a better incision. The surgeon always maintains control of the laser. The net effect of the intelligent aiming system is to subtract away nearly all patient motions. CONCLUSION: Laser surgery can be performed with greater accuracy and reduced unwanted tissue damage with the predictive tracking of motion.

Computer Simulation↗