Nathan Jowett

Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States

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Publications (17)27.96 Total impact

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    ABSTRACT: Silver nitrate is sometimes used as a means of chemical cauterization for control of minor bleeding and management of hypergranulation tissue following bedside head and neck procedures. There are only few reports available on the imaging appearance of silver nitrate and its potential to mimic a foreign body. We report a case of a patient presenting with dysphagia, odynophagia, and fever following dental work who had a peritonsillar incision and drainage for treatment of a deep neck space infection. During the procedure, silver nitrate was applied to halt the bleeding. Patient was subsequently transferred to another institution. Since the patient was not showing significant clinical improvement on antibiotic therapy, a computed tomography (CT) scan was performed demonstrating a hyperdense structure lodged in the pharyngeal mucosal space in the oropharynx and soft palate that was mistaken for a foreign body such as bone. Silver nitrate can have density similar to bone but does not have the normal architecture of bone with cortex and marrow on CT. Familiarity with the appearance of silver nitrate on CT, lack of bone architecture, and proper documentation and communication of the use of silver nitrate to the consultant radiologist and medical personnel could help avoid misdiagnosis and potentially unnecessary surgical exploration.
    05/2015; 7(5):100-3. DOI:10.4329/wjr.v7.i5.100
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    ABSTRACT: The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 μm are efficient for obtaining applanation-free deep cuts on porcine corneas.
    PLoS ONE 03/2015; 10(3):e0120944. DOI:10.1371/journal.pone.0120944 · 3.23 Impact Factor
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    Balazs B Lörincz · Nathan Jowett · Rainald Knecht ·
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    ABSTRACT: Transoral robotic surgery has become an accepted first-line treatment for T1 and T2 HNSCC. The growing popularity of this procedure is the result of mounting skepticism as to the survival and quality of life benefits of primary chemoradiation over definitive surgery, the rising incidence of HPV-positive oropharyngeal cancer in progressively younger patients, and the advantages of TORS over transoral laser microsurgery and open surgery. The authors use their experience and data gained from the TORS-based management of more than a hundred patients to establish a systematic approach to the use of TORS in HNSCC. This approach is constructed on a framework which goal is to select the primary treatment option that is most likely to reduce morbidity while preserving function and maintaining oncologic safety. A consensus regarding the indications of TORS and its role in the multidisciplinary management of HNSCC is to be established. This article is protected by copyright. All rights reserved. © 2015 Wiley Periodicals, Inc.
    Head & Neck 03/2015; DOI:10.1002/hed.24059 · 2.64 Impact Factor
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    ABSTRACT: The objective of this study was to evaluate long-term vestibulocochlear functional outcomes of patients operated for unilateral vestibular schwannoma via the retro-sigmoid approach. Patients who underwent vestibular schwannoma resection via retro-sigmoid approach between 2004 and 2008 at our institution, without prior surgical or radio-surgical therapy were considered to be eligible for this study. Preoperative auditory and vestibular symptoms were assessed retrospectively. Postoperative symptoms were prospectively assessed using a standardised questionnaire, pure tone audiometry, video-oculography, and rotary chair testing. Out of a total of 203 patients, 120 were eligible for this study, of whom 64 responded to follow-up requests and could be enrolled. Serviceable hearing was reported in 42 patients (66 %) preoperatively and was maintained in 18 (43 %) postoperatively. While no significant change in rate of tinnitus and balance impairment between pre- and postoperative periods was detected, vertigo decreased significantly (40 to 28 %, p < 0.001). Postoperative video-oculography demonstrated vestibular paresis in 80 %. Rotary chair testing demonstrated normal or central compensation in 84 %. Absence of central compensation was associated with postoperative balance disturbance (p = 0.035). Increasing tumour size and patient age, also decreasing quality of preoperative hearing were independent factors predictive of a postoperative non-serviceable hearing (p = 0.020, p = 0.039 and p = 0.002, respectively). Resection of vestibular schwannoma via the retro-sigmoid approach is associated with improvement in postoperative vertiginous symptoms. Absence of central compensation leads to increased postoperative balance disturbances. Preservation of serviceable postoperative hearing is associated with good preoperative hearing status, younger age, and smaller tumours.
    Archiv für Klinische und Experimentelle Ohren- Nasen- und Kehlkopfheilkunde 02/2015; DOI:10.1007/s00405-015-3561-5 · 1.55 Impact Factor
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    ABSTRACT: The carbon dioxide (CO2) laser is routinely used in glottic microsurgery for the treatment of benign and malignant disease, despite significant collateral thermal damage secondary to photothermal vaporization without thermal confinement. Subsequent tissue response to thermal injury involves excess collagen deposition resulting in scarring and functional impairment. To minimize collateral thermal injury, short-pulse laser systems such as the microsecond pulsed erbium:yttrium–aluminium-garnet (Er:YAG) laser and picosecond infrared laser (PIRL) have been developed. This study compares incisions made in ex vivo human laryngeal tissues by CO2 and Er:YAG lasers versus PIRL using light microscopy, environmental scanning electron microscopy (ESEM), and infrared thermography (IRT). In comparison to the CO2 and Er:YAG lasers, PIRL incisions showed significantly decreased mean epithelial (59.70 µm) and subepithelial (22.15 µm) damage zones (p 2 lasers (p 2 and Er:YAG laser incisions. IRT demonstrated median temperature rise of 4.1 K in PIRL vocal fold incisions, significantly less than for Er:YAG laser cuts (171.85 K; p 2 and Er:YAG lasers in human glottis and supraglottic tissues.
    Archiv für Klinische und Experimentelle Ohren- Nasen- und Kehlkopfheilkunde 01/2015; 272(4). DOI:10.1007/s00405-015-3501-4 · 1.55 Impact Factor
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    ABSTRACT: BACKGROUND: This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination. METHODS: The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions. RESULTS: A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue. CONCLUSION: The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.
    Der Ophthalmologe 06/2014; 111(6). DOI:10.1007/s00347-013-2995-7 · 0.50 Impact Factor

  • 85. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V., Dortmund; 05/2014
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    ABSTRACT: Advances in operative technique, instrumentation, and prosthesis design in otosclerosis surgery continue since Shea performed the first successful surgery. This is the first analysis to specifically compare post-operative hearing outcomes following stapedotomy surgery performed under local versus general anesthesia. Hearing outcomes were further stratified by comparing conventional perforator and Er:YAG laser ablation perforation techniques. Pre- and post-operative audiograms were retrospectively analyzed together with the method of anesthesia and the perforation technique for all patients with otosclerosis who underwent stapedotomy between 1998 and 2007. Pre-operative individual standard audiometry frequency thresholds (IFTs), air (AC) and bone conduction pure tone averages (PTA), and air bone gaps (ABG) were compared against post-operative results. Differences between pre- and post-operative PTAs and ABGs were compared between patients who received stapedotomy under local versus general anesthesia, as well as for patients who underwent conventional versus Er:YAG laser ablation perforations. Eighty-six patients were identified of which 24 % (n = 21) received local and 76 % (n = 65) received general anesthesia. Post-operative audiograms were available for 84 and 48 patients, respectively. Significant improvements were seen across all groups for standard 4-frequency AC-PTA and ABG and for IFTs up to 3 kHz. No significant difference was seen for IFTs between 4 and 6 kHz. A significant decline in post-operative hearing thresholds was seen at 8 kHz. Significant improvements in PTA and ABG were seen for all groups. There was a trend toward general compared to local anesthesia post-operative hearing results furthermore in combination with conventional perforation technique then with laser technique.
    Archives of Oto-Rhino-Laryngology 04/2014; 272(9). DOI:10.1007/s00405-014-3014-6 · 1.55 Impact Factor
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    ABSTRACT: Background and ObjectiveA precise means to cut bone without significant thermal or mechanical injury has thus far remained elusive. A novel non-ionizing ultrafast pulsed picosecond infrared laser (PIRL) may provide the solution. Tissue ablation with the PIRL occurs via a photothermal process with thermal and stress confinement, resulting in efficient material ejection greatly enhanced through front surface spallation photomechanical effects. By comparison, the Er:YAG laser (EYL) ablates via photothermal and cavitation-induced photomechanical effects without thermal or acoustic confinement, leading to significant collateral tissue injury. This study compared PIRL and EYL bone ablation by infrared thermography (IRT), environmental scanning electron microscopy (ESEM), and histology.Study DesignProspective, comparative, ex vivo animal model.SettingOptics laboratory.Subjects and Methods Ten circular area defects were ablated in ex vivo chicken humeral cortex using PIRL and EYL at similar average power (~70 mW) under IRT. Following fixation, ESEM and undecalcified light microscopy images were obtained and examined for signs of cellular injury.ResultsPeak rise in surface temperature was negligible and lower for PIRL (1.56°C; 95% CI, 0.762-2.366) compared to EYL ablation (12.99°C; 95% CI, 12.189-13.792) (P < .001). ESEM and light microscopy demonstrated preserved cortical microstructure following PIRL ablation in contrast to diffuse thermal injury seen with EYL ablation. Microfractures were not observed.Conclusion Ablation of cortical bone using the PIRL generates negligible and significantly less heat than EYL ablation while preserving cortical microstructure. This novel laser has great potential in advancing surgical techniques where precision osseous manipulation is required.
    Otolaryngology Head and Neck Surgery 12/2013; 150(3). DOI:10.1177/0194599813517213 · 2.02 Impact Factor
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    ABSTRACT: Conventional lasers ablate tissue through photothermal, photomechanical, and/or photoionizing effects, which may result in collateral tissue damage. The novel nonionizing picosecond infrared laser (PIRL) selectively energizes tissue water molecules using ultrafast pulses to drive ablation on timescales faster than energy transport to minimize collateral damage to adjacent cells. Animal cadaver study. Cuts in porcine laryngeal epithelium, lamina propria, and cartilage were made using PIRL and carbon dioxide (CO2) laser. Lateral damage zones and cutting gaps were histologically compared. The mean widths of epithelial (8.5 μm), subepithelial (10.9 μm), and cartilage damage zones (8.1 μm) were significantly lower for cuts made by PIRL compared with CO2 laser (p < 0.001). Mean cutting gaps in vocal fold (174.7 μm) and epiglottic cartilage (56.3 μm) were significantly narrower for cuts made by PIRL compared with CO2 laser (P < 0.01, P < 0.05). PIRL ablation demonstrates superiority over CO2 laser in cutting precision with less collateral tissue damage. N/A. Laryngoscope, 123:2770–2775, 2013
    The Laryngoscope 11/2013; 123(11). DOI:10.1002/lary.24124 · 2.14 Impact Factor
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    ABSTRACT: Despite causing significant thermocoagulative insult, use of the carbon dioxide (CO2) laser is considered gold standard in surgery for early stage larynx carcinoma. Limited attention has been paid to the use of the erbium:yttrium-aluminium-garnet (Er:YAG) laser in laryngeal surgery as a means to reduce thermal tissue injury. The objective of this study is to compare the extent of thermal injury and precision of vocal fold incisions made using microsecond Er:YAG and superpulsed CO2 lasers. In the optics laboratory ex vivo porcine vocal folds were incised using Er:YAG and CO2 lasers. Lateral epithelial and subepithelial thermal damage zones and cutting gap widths were histologically determined. Environmental scanning electron microscopy (ESEM) images were examined for signs of carbonization. Temperature rise during Er:YAG laser incisions was determined using infrared thermography (IRT). In comparison to the CO2 laser, Er:YAG laser incisions showed significantly decreased epithelial (236.44 μm) and subepithelial (72.91 μm) damage zones (p < 0.001). Cutting gaps were significantly narrower for CO2 (878.72 μm) compared to Er:YAG (1090.78 μm; p = 0.027) laser. ESEM revealed intact collagen fibres along Er:YAG laser cutting edges without obvious carbonization, in comparison to diffuse carbonization and tissue melting seen for CO2 laser incisions. IRT demonstrated absolute temperature rise below 70 °C for Er:YAG laser incisions. This study has demonstrated significantly reduced lateral thermal damage zones with wider basal cutting gaps for vocal fold incisions made using Er:YAG laser in comparison to those made using CO2 laser.
    Archives of Oto-Rhino-Laryngology 10/2013; 271(5). DOI:10.1007/s00405-013-2761-0 · 1.55 Impact Factor
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    ABSTRACT: Endotracheal intubation has been associated with a threefold higher incidence of laryngopharyngeal complaints following anesthesia in comparison to laryngeal mask airway. Such complaints, including hoarseness and sore throat, have been reported in up to 90 % of patients within 24 h of extubation. The purpose of this study was to determine which preoperatively documented clinical and anatomic parameters are predictive of laryngo-pharyngeal trauma resulting from elective endotracheal intubation. Fifty-three patients undergoing ENT procedures requiring general anesthesia with endotracheal intubation were recruited. Pre and postoperative laryngostroboscopic examination was performed and findings correlated to preoperative clinical and anatomic parameters. Readily assessed anatomic parameters including height (>180 cm) and weight (>80 kg) correlated significantly to the Eckerbom grade of intubation-associated acute laryngeal injury (rs = 0.374; p = 0.006 and rs = 0.278; p = 0.044, respectively). The mandibular protrusion test also correlated significantly to the Eckerbom grade (rs = 0.462, p = 0.001) while the upper-lip-bite test showed significant correlation to impaired vocal fold oscillation (rs = 0.288, p = 0.036), with injury prediction sensitivities of 37.5 and 39.4 %, respectively. No parameters correlated to subjective complaints (n = 5, 9.2 %). This study provides suggestions on how to improve the classification of intubation-associated laryngeal injuries as well as providing the basis for larger clinical trials in other surgical subspecialties.
    Archives of Oto-Rhino-Laryngology 08/2013; 271(2). DOI:10.1007/s00405-013-2659-x · 1.55 Impact Factor
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    ABSTRACT: Objectives: A precise method to ablate bone without significant thermal or acoustic injury has remained elusive. A novel non-ionizing ultrafast pulsed picosecond infrared laser (PIRL) may provide the solution. The PIRL ablates tissue through purely photomechanical means, via a thermoelastic front spallation effect, with near complete thermal and acoustic transient confinement. In contrast, the Er:YAG laser ablates tissue via a micro-explosive vaporization mechanism. This study compares PIRL and Er:YAG laser ablation of bone by infrared thermography (IRT), digital microscopy, and electron microscopy.
    Otolaryngology Head and Neck Surgery 08/2013; 149(2 Suppl):P91-P92. DOI:10.1177/0194599813495815a173 · 2.02 Impact Factor
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    ABSTRACT: Objectives: The Er:YAG laser (EYL) provides an efficient means of precise and predictable bone ablation, without intense thermal injury associated with CO2 laser use. Use of the EYL in otology is possible, but must be undertaken with caution as ablation is associated with brief intense acoustic transients up to 120 dB. This study details the use of the EYL in otologic and neuro-otologic surgery and compares ablation using a commercially available EYL with customizable glass fiber tips versus diamond and cutting burrs by means of infrared thermal imaging (IRT) and environmental scanning electron microscopy (ESEM).
    Otolaryngology Head and Neck Surgery 08/2013; 149(2 Suppl):P224-P224. DOI:10.1177/0194599813496044a250 · 2.02 Impact Factor
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    ABSTRACT: Objectives: One of the main causes for chronic otitis media is a tubal dysfunction which can now be treated with the endonasal dilatation of the Eustachian tube with the help of a novel balloon catheter.
    Otolaryngology Head and Neck Surgery 08/2013; 149(2 Suppl):P99-P99. DOI:10.1177/0194599813495815a196 · 2.02 Impact Factor
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    ABSTRACT: IMPORTANCE Despite significant advances in surgery, most surgical tools remain basic. Lasers provide a means of precise surgical ablation, but their clinical use has remained limited because of undesired thermal, ionizing, or acoustic stress effects leading to tissue injury. A novel ultrafast, nonionizing, picosecond infrared laser (PIRL) system has recently been developed and is capable, in theory, of ablation with negligible thermal or acoustic stress effects. OBJECTIVE To measure and compare heat generation by means of thermography during ablation of ex vivo porcine skin by conventional microsecond-pulsed erbium:YAG (Er:YAG) laser and picosecond infrared laser (PIRL). DESIGN AND SETTING This study was conducted in an optics laboratory and used a pretest-posttest experimental design comparing 2 methods of laser ablation of tissue with each sample acting as its own control. INTERVENTION Ex vivo porcine skin was ablated in a 5-mm line pattern with both Er:YAG laser and PIRL at fluence levels marginally above ablation threshold (2 J/cm2 and 0.6 J/cm2, respectively). MAIN OUTCOMES AND MEASURES Peaks and maxima of skin temperature rises were determined using a thermography camera. Means of peak temperature rises were compared using the paired sample t test. Ablation craters were assessed by means of digital microscopy. RESULTS Mean peak rise in skin surface temperature for the Er:YAG laser and PIRL was 15.0°C and 1.68°C, respectively (P < .001). Maximum peak rise in skin surface temperature was 18.85°C for the Er:YAG laser and 2.05°C for the PIRL. Ablation craters were confirmed on digital microscopy. CONCLUSIONS AND RELEVANCE Picosecond infrared laser ablation results in negligible heat generation, considerably less than Er:YAG laser ablation, which confirms the potential of this novel technology in minimizing undesirable thermal injury associated with lasers currently in clinical use.
    JAMA Otolaryngology - Head and Neck Surgery 08/2013; 139(8):828-33. DOI:10.1001/jamaoto.2013.3974 · 1.79 Impact Factor
  • Nathan Jowett · Alex M Mlynarek ·
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    ABSTRACT: The article discusses the fundamental principles of cheek reconstruction and summarizes recently published techniques and reviews in the field. Reconstruction of the cheek is a complex endeavour. Patient, defect, and potential donor site factors must be carefully considered in the restoration of cheek form and function. Fortunately the surgeon, each with his or her own personal preferences and experience, has a wealth of techniques available from which to choose. New flaps and techniques are described including recent reviews of traditional techniques. Examples include a modification to the Mustardé flap, an axial pedicled flap from the radix nasi region, a technique of superficial musculoaponeurotic system plication to achieve primary closure of large defects, and reviews of the submental island flap, the subcutaneous cervicofacial flap, the medial sural artery perforator flap, and the anterolateral thigh flap. Surgical innovation and conscientious assessments of traditional techniques continue to advance the field of cheek reconstruction towards improved aesthetic and functional outcomes.
    Current opinion in otolaryngology & head and neck surgery 05/2010; 18(4):244-54. DOI:10.1097/MOO.0b013e32833a6d7f · 1.84 Impact Factor

Publication Stats

48 Citations
27.96 Total Impact Points


  • 2015
    • Massachusetts Eye and Ear Infirmary
      Boston, Massachusetts, United States
    • The University of Calgary
      Calgary, Alberta, Canada
  • 2013-2015
    • McGill University
      Montréal, Quebec, Canada
    • University Medical Center Hamburg - Eppendorf
      • • Department of Oto-, Rhino-, Laryngology
      • • Department of Ophthalmology
      Hamburg, Hamburg, Germany
    • University of Hamburg
      Hamburg, Hamburg, Germany
  • 2010
    • Jewish General Hospital
      Montréal, Quebec, Canada