Rhinolith: Examining the clinical, radiological and surgical features of 23 cases

Publication date: Available online 28 December 2018

Source: Auris Nasus Larynx

Author(s): Ceyhun Aksakal

Abstract

Objective

Rhinolith is a hard nasal mass formed in time by the mineral salts around an endogenous or exogenous-originating nidus. Rhinolith, which is seen rarely, has been reported in the literature as case reports. In this study, we are presenting the demographic and clinical features together with accompanying sinonasal pathologies of 23 rhinolith cases.

Methods

The medical records and radiological findings of 23 cases, who were operated for rhinolith between January 2010 and June 2018 in Tokat State Hospital, were analyzed retrospectively. The age, gender, the side where rhinolith exists, nidus presence, type of surgery and sinonasal pathologies that accompany rhinolith, and accompanying secondary sinonasal surgeries were examined.

Results

A total of 17 (73.2%) of the 23 cases were female, and 6 (26.8%) were male. The mean age was 24.9 years. The symptoms that were seen in the patients were nasal obstruction (100%), rhinorrhea (82.6%), nasal malodor (78.2%), oral malodor (26%), headache (26%), epistaxis (17.3%), face pain (4,3%), respectively. Nidus could be detected in 6 patients. The most frequent localization of rhinolith was between the inferior concha and the nasal septum (n = 21). The most common concomitant sinonasal pathology in rhinolith was septum deviation (43.4%); and the second most common pathology was mucosal thickening (30.4%) in the maxillary sinus. The surgery type that accompanied rhinolith at the highest frequency was septoplasty (n = 5). Other surgeries were septorhinoplasty (n = 1), antrochoanal polyp excision (n = 1), adenoidectomy (n = 1).

Conclusion

The most common symptoms of rhinolith, which is a rare nasal pathology, are nasal obstruction and rhinorrhea. Radiological imaging together with a rigid endoscopy is important especially to evaluate the placement of rhinolith. In addition to this, radiological imaging, evaluation of the sinuses that are not sufficiently evaluated with rigid endoscope are important for planning the type of the operation and secondary surgical procedures which may accompany.

http://bit.ly/2BLcswE

Co-existing ‘Oral Potentially Malignant Disorders’ – A high risk clinical entity?

Publication date: Available online 28 December 2018

Source: Oral Oncology

Author(s): Prashanth Panta

http://bit.ly/2VhG11N

Carcinoma Presenting as Idiopathic Anterior Glottic Webs: A Case Series

An anterior glottic web is an abnormal fusion of the anterior aspect of the membranous vocal folds. Noncongenital glottic webs are usually iatrogenic from intubation or laryngeal surgery. We present six adult patients whose initial in‐office diagnoses were consistent with "idiopathic" benign anterior glottic webs as determined by three laryngologists (a.m.k., j.m.b., m.j.p.). Further evaluation revealed the diagnoses of laryngeal squamous cell carcinoma in all cases. The high risk of malignancy in cases of idiopathic anterior glottic web necessitates biopsy for tissue diagnosis of all such lesions. Laryngoscope, 2018

http://bit.ly/2LCBAKk

The presence of eosinophil aggregates correlates with increased postoperative prednisone requirement

Objectives/Hypothesis

Failure after sinus surgery is multifactorial, but often due to recurrence of inflammatory mucosal disease. Postoperative steroid requirements for controlling mucosal inflammation may provide insight into predicting which patients require more aggressive medical therapy to prevent disease relapse.

Study Design

Retrospective chart review.

Methods

A review was performed of patients who underwent functional endoscopic sinus surgery (FESS) for refractory chronic rhinosinusitis (CRS). Sino‐Nasal Outcome Test‐22 scores and cumulative prednisone dose (milligrams) requirements at 1, 3, and 6 months postoperatively were reviewed. A structured histopathology report of 11 variables was accessed to correlate histopathology with postoperative steroid requirements.

Results

One hundred one patients were reviewed including 42 CRS with nasal polyps and 59 CRS without nasal polyps patients. CRS patients with eosinophilia required greater cumulative steroids to control disease at 1‐, 3‐, and 6‐month postoperative intervals (P < .026, P < .007, P < .013, respectively) compared to patients without eosinophilia. Patients with tissue eosinophil aggregates required the highest cumulative steroids at 1‐, 3‐, and 6‐month postoperative intervals (P < .003, P < .001, P < .001, respectively). When removing patients with eosinophil aggregates from the eosinophilia group, no difference persisted between patients with eosinophilia and those without eosinophilia at all intervals (P = .664, P = .735, P = .800, respectively). No other histopathology variable correlated with postoperative steroid requirement.

Conclusions

Tissue eosinophil aggregates appear to be the largest driving factor for increased prednisone requirements after sinus surgery to control mucosal disease than mere presence of eosinophils. This key finding may identify patients at high risk for failure after sinus surgery and guide more proactive postoperative management.

Level of Evidence

4 Laryngoscope, 2018

http://bit.ly/2s1Eqzw

Cervical slide tracheoplasty in adults with laryngotracheal stenosis

Objectives

1) Evaluate success rates for adults undergoing cervical slide tracheoplasty. 2) Examine complication rates of slide tracheoplasty in adults.

Methods

A retrospective cohort of adults > 21 years of age undergoing cervical slide tracheoplasty for tracheal stenosis between October 2011 and August 2017 was reviewed. Comorbidities, stenosis grade, etiology of stenosis, primary versus revision surgery, complications, and number of adjunct endoscopic procedures required postoperatively were evaluated.

Results

Nineteen patients (63% female) underwent cervical slide tracheoplasty during the study period (median age 30 years, range 21–70). The most common etiology of stenosis was iatrogenic (68%), followed by congenital etiologies (26%). Fifty‐eight percent of patients had undergone a previous open airway procedure. Thirty‐nine percent were tracheostomy‐dependent prior to surgery, and the remainder had severe exercise intolerance. Sixty‐three percent were successfully extubated on the operating room table at the end of the procedure. Six (32%) patients experienced surgical complications, including one anastomotic dehiscence, three neck abscesses requiring incision and drainage (I&D), and replacement of adjunctive airway device in two patients. Seventy percent of the patients required ≥ 1 endoscopic dilation in the first 12 months following surgery, with a median of one (range 1–8) procedure. At most recent follow‐up (median 8 months, range 4–64 months), 18 of 19 (95%) of patients had minimal airway symptoms without need for tracheostomy. The one patient who was not decannulated expired of a presumed cardiac event prior to decannulation.

Conclusion

Cervical slide tracheoplasty is an excellent reconstructive option for adult patients with tracheal stenosis, including those with history of previous airway reconstruction.

Level of Evidence

4. Laryngoscope, 2018

http://bit.ly/2LL7p3X

Efficacy of tranexamic acid on operative bleeding in endoscopic sinus surgery: A meta‐analysis and systematic review

Objectives

Tranexamic acid might help control bleeding during surgery because of antifibrinolytic characteristics. We aimed to evaluate the effectiveness of systemic tranexamic acid compared to control in blood loss, operative time, and surgical field and incidence of postoperative emesis and thromboembolism in endoscopic sinus surgery.

Methods

Two authors independently searched six databases (PubMed, SCOPUS, Embase, the Web of Science, Google Scholar, and the Cochrane database) from their inception to July 2018. The included studies compared perioperative tranexamic acid administration (treatment group) with a placebo, and the outcomes of interest were intraoperative morbidities, including surgical time, operative bleeding, and hypotension; postoperative morbidities such as nausea and vomiting; and coagulation profiles.

Results

Seven studies comprising 562 participants were reviewed in this study. Operative time (standardized mean difference (SMD) = −0.60; 95% confidence interval (CI)[−0.93, −0.29]) and intraoperative blood loss (SMD = −0.66; 95% CI [−0.86, −0.46]) were statistically lower in the treatment group than placebo group; and the quality of the surgical field (SMD = −0.80; 95% CI [−1.12; −0.48]) and surgeon satisfaction (SMD = 1.74; 95% CI [1.36; 2.13]) were statistically higher in the treatment group than the placebo group. By contrast, there were no significant differences in the hemodynamic (SMD = 0.08; 95% CI [−0.20; 0.37]) and coagulation profiles (SMD = −0.18; 95% CI [−0.42, 0.07]) of the two groups. Additionally, tranexamic acid had no significant effect on emetic or thrombotic events compared to placebo.

Conclusion

This meta‐analysis showed that the systemic administration of tranexamic acid could decrease operative time and blood loss intraoperatively, increasing the satisfaction of surgeons. It did not provoke intraoperative hemodynamic instability, postoperative emetic events, or coagulation profile abnormality. Only a small number of studies were enrolled, so further trials are needed to confirm the results of this study.

Level of Evidence

IA. Laryngoscope, 2018

http://bit.ly/2s2aV0o

Comparison of endoscopic and microscopic ear surgery in pediatric patients: A meta‐analysis

Objectives

Recently, the endoscope has been increasingly introduced for middle‐ear surgery. To evaluate the postoperative outcomes of endoscopic ear surgery (EES) in pediatric patients, we did a qualitative analysis with a systematic review and quantitative analysis with meta‐analysis of available literature.

Methods

Studies reporting the comparative surgical outcomes of EES in pediatric patients were systematically reviewed by searching the MEDLINE, PubMed, and Embase databases from database inception through 2017. The selected articles included clinical studies conducted with at least 30 subjects and at least one postoperative parameter, including residual or recurrent cholesteatoma and graft success in tympanoplasty. Two investigators independently reviewed all studies and extracted the data using a standardized form. A meta‐analysis was performed using a random‐effects model and qualitative review was performed on the smaller studies.

Results

Ten studies were identified as appropriate for quantitative meta‐analysis and 19 studies for qualitative analysis. In the meta‐analysis, residual or recurrence rate of cholesteatoma was significantly lower in the EES group than in the microscopic ear surgery (MES) group (odds ratio [OR]: 0.56, 95% confidence interval [CI]: 0.38‐0.84, P = .005). The graft success rate of tympanoplasty was not statistically different between EES and MES groups (OR: 0.72, 95% CI: 0.41‐1.26, P = .249). In the qualitative analysis, most of the studies reported similar audiological outcomes after tympanoplasty and success rate of cholesteatoma removal between the two groups.

Conclusions

It appears that EES reduces the risk of residual cholesteatoma in children and that the success of perforation closure is equivalent to MES.

Laryngoscope, 00:1–9, 2018

http://bit.ly/2LFrGI7

Septal fractures predict poor outcomes after closed nasal reduction: Retrospective review and survey

Objectives/Hypothesis

To determine outcomes of patients with displaced nasal bone fractures after closed nasal reduction (CNR).

Study Design

Retrospective patient review.

Methods

Review of all patients presenting to the emergency department of a tertiary‐care, level 1 trauma hospital with a nasal bone fracture over a 2‐year period, followed by telephone survey after CNR.

Results

Six hundred seven patients presented to the emergency department in 2015 and 2016 with a diagnosis of nasal bone fracture. Of these, 134 patients met inclusion criteria and underwent CNR without septal reduction. Those with sports‐related injuries and those with a septal fracture identified on computed tomography imaging were significantly more likely to undergo CNR. Ninety‐one patients completed the post‐CNR telephone survey. Over 90% of patients were satisfied with the procedure. However, patients with septal fractures reported worse outcomes, as 53.6% versus 24.1% (P = .0025) disagreed that CNR improved nasal breathing. Of all patients, 11 (2%) eventually underwent septorhinoplasty, with the presence of septal fracture on imaging a significant risk factor.

Conclusions

Nasal bone fractures are a common injury, often managed initially with CNR. Patients with septal fractures should be counseled on the high risk of posttraumatic nasal deformity and obstruction despite CNR. In addition, addressing a septal fracture found on imaging may be warranted with either closed septal reduction or early aggressive management given the poorer outcomes seen in the present study. Although these patients are more likely to have definitive treatment, many forego later intervention despite persistent symptoms, emphasizing the need for early intervention or close follow‐up.

Level of Evidence

3 Laryngoscope, 2018

http://bit.ly/2rZtra3

Modiolar rotational cheiloplasty: Addressing the central oval in facial paralysis

Objectives/Hypothesis

Current static reanimation of the midface fails to provide adequate functional and aesthetic improvement; there is a need for more effective static correction of the ptotic midface. Our objective herein was to describe a novel method of static midface suspension that produces improved functional and aesthetic outcomes compared to previous techniques. Specifically, our goal was to describe the technique of alar and oral commissure repositioning via modiolar rotational cheiloplasty with alar base transposition, and gingivobuccal sulcoplasty.

Study Design

Retrospective case series.

Methods

We retrospectively reviewed the results of a series of adult patients desiring surgical intervention for paralysis of the central oval of the face at a tertiary care referral center. We present our technique of modiolar rotational cheiloplasty first with an example case, including subjective outcomes reported by the patient and objective improvements in facial appearance using Massachusetts Eye and Ear Infirmary Facial Assessment by Computer Evaluation Program (MEEI FACE‐Gram) software, then demonstrate long‐term outcomes from the series.

Results

Clinically, patients noted subjective improvement in drooling, buccal stasis of food, dysarthria, nasal obstruction, and overall appearance. Patients with significant atrophy and lateral displacement of the lower lip underwent concomitant wedge resection, which further improved the symmetry and position of the lips. The MEEI FACE‐Gram software demonstrated objective improvement in symmetry of smile and position of the philtrum and nasal base in an example case.

Conclusions

Modiolar rotational cheiloplasty with alar base transposition is an effective and efficient static procedure for midface palsy that improves both function and appearance.

Level of Evidence

4 Laryngoscope, 2018

http://bit.ly/2LL7nZT

Contemporary Review and Case Report of Botulinum Resistance in Facial Synkinesis

Background

Botulinum resistance poses significant treatment challenges for both patients and healthcare practitioners. We first present a case highlighting botulinum resistance in a patient who failed to respond to alternative formulations but who responded remarkably to incobotulinum toxinA, an identical toxin free of complexing proteins. Secondly, we provide a treatment algorithm and a review of the literature detailing clinical and immunochemical botulinum resistance.

Results

Patients with botulinum resistance show a predisposition to failure on subsequent injections and possess a propensity toward neutralizing and nonneutralizing antibody development. The mechanisms of resistance are not entirely understood but thought to be secondary to an immunologic response. Risk factors for resistance include higher botulinum doses, more frequent injections, and high total lifetime dosage. Patients may still respond to other botulinum formulations or subtypes; however, this effect may be temporary.

Conclusion

This case report describes a patient who responded to incobotulinum toxinA after failing treatment with the identical toxin compounded with buffer proteins, ultimately supporting the possibility of immune‐mediated resistance to the surrounding proteins and not the toxin itself. Often, impending treatment resistance is preceded by a poor or limited clinical response. Antibody testing is not indicated because it is neither sensitive nor specific and does not change clinical practice. Initially, higher doses of botulinum may overcome resistance without increasing treatment frequency, and side effects are far less common in those with clinical resistance. If higher dosages fail to produce a response, alternative botulinum formulations or subtypes can be considered. Laryngoscope, 2018

http://bit.ly/2s0JZOO

Otosyphilis: Resurgence of an Old Disease

Objectives

To describe the clinical characteristics of patients presenting with a new diagnosis of otosyphilis over the past 10 years in a large, urban, safety‐net hospital affiliated with a large county sexually transmitted disease clinic.

Methods

Retrospective case series. A chart review was performed of all patients who presented to an adult otolaryngology clinic with a new diagnosis of syphilis and hearing loss from January 2008 to December 2017.

Results

Twelve patients met the criteria for "suspected" or "likely" otosyphilis based on Centers for Disease Control and Prevention definitions. The average age was 48 years (range 19–59). All were male. Nine (75%) were men who have sex with men. Eight (67%) were positive for human immunodeficiency virus. One (8%) presented with primary, nine (75%) with secondary, and two (17%) with early latent syphilis. Seven (58%) presented with bilateral audiogram‐confirmed hearing loss, two (17%) with unilateral hearing loss, and three (25%) with suspected hearing loss based on fluctuating symptoms. Nine (75%) presented with tinnitus and two (17%) with vertigo. The median duration of otologic symptoms prior to presentation was 2 weeks (range: 0–16 weeks). All presented within the last 2 years surveyed.

Conclusion

We have seen an increase in the number of otosyphilis cases in our clinic. We suspect otosyphilis may be underdiagnosed and emphasize the importance of screening for syphilis in patients with new audiologic symptoms of vertigo, tinnitus, or hearing loss.

Level of Evidence

4. Laryngoscope, 2018

http://bit.ly/2QWDsDx

Early detection of esophageal second primary tumors using Lugol chromoendoscopy in patients with head and neck cancer: A systematic review and meta‐analysis

Abstract

Background

Early detection of esophageal secondary primary tumors (SPTs) in head and neck squamous cell carcinoma (HNSCC) patients could increase patient survival. The purpose of this study was to determine the diagnostic yield of esophageal SPTs using Lugol chromoendoscopy.

Methods

A systematic review of all available databases was performed to find all Lugol chromoendoscopy screening studies.

Results

Fifteen studies with a total of 3386 patients were included. The average yield of esophageal‐SPTs in patients with HNSCC was 15%. The prevalence was the highest for patients with an index hypopharyngeal (28%) or oropharyngeal (14%) tumor. The esophageal‐SPTs were classified as high‐grade dysplasia in 49% of the cases and as invasive carcinoma's in 51%.

Conclusion

Our results show that 15% of the patients with HNSCC that underwent Lugol chromoendoscopy were diagnosed with an esophageal‐SPT. Based on these results there is enough evidence to perform Lugol chromoendoscopy, especially in an Asian patient population.

http://bit.ly/2CFXcmt

Comparison of contemporary staging systems for oropharynx cancer in a surgically treated multi‐institutional cohort

Abstract

Background

Between the publication of the Union of International Cancer Control staging system (UICC) 7th and 8th editions, other staging algorithms for oropharyngeal squamous cell carcinoma (OPSCC) were proposed from Radiation Therapy Oncology Group (RTOG), MD Anderson Cancer Center (MDACC), and Yale University.

Methods

With C‐statistics, the above‐mentioned five staging algorithms were compared for overall and relapse‐free survival endpoints in a multi‐institutional cohort of OPSCC cases (n = 338) treated with primary surgery.

Results

Pathological UICC 8th ed yielded the highest C‐indexes in the entire cohort and in the HPV− subset, whereas MDACC was superior for HPV+ OPSCC. RTOG was the simplest and holistic algorithm with a noninferior discriminatory power.

Conclusion

UICC 8th ed, MDACC, and RTOG offer moderate and comparable efficacy for staging in this OPSCC patient cohort undergoing surgical treatment. Notable discrepancy between clinical and pathological UICC 8th ed algorithms poses potential concerns in diagnosis, treatment, research, and data management.

http://bit.ly/2TeTZ2r

Impact of social deprivation on the outcome of major head and neck cancer surgery in England: A national analysis

Abstract

Background

Socioeconomic status plays an important role in the incidence and prognosis of many cancers. We examined the relationship between social deprivation and clinical outcomes in patients undergoing major surgery for head and neck cancer.

Methods

A retrospective population‐based observational study was performed. Patients undergoing head and neck surgical procedures in England between 2002 and 2012 were identified. This totaled 5051 patients in the less socially deprived (LSD) and 7282 in the more socially deprived (MSD) group.

Results

MSD patients were younger (61 vs 63) and were more likely to present with hypopharyngeal‐laryngeal cancers (41% vs 30%). They had higher burdens of morbidity and more frequently required emergency surgery (odds ratio [OR] 1.74 [95% CI 1.52‐1.99]). Following surgery, MSD patients had higher lengths of inpatient stay (OR 1.72 [95% CI 1.57‐1.88]) and higher proportions of both inpatient (OR 1.47 [95% CI 1.19‐1.82]) and overall mortality (OR 1.34 [95% CI 1.24‐1.45]).

Conclusion

Increasing socioeconomic deprivation is associated with poor health outcomes in patients with head and neck cancer.

http://bit.ly/2CGhzjd

Long‐term outcome and pattern of failure for patients with nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy

Abstract

Purpose

To analyze the long‐term outcome and pattern of failure for patients with nasopharyngeal carcinoma (NPC) after intensity‐modulated radiotherapy (IMRT).

Methods and materials

Patients with NPC after IMRT from 2001 to 2008 were recruited (n = 865). Clinical features, laboratory data, and treatments were collected.

Results

The 10‐year local recurrence‐free survival, distant metastasis‐free survival, and disease‐specific survival (DSS) were 92.0%, 83.4%, and 78.6%, respectively. A total of 209 patients died: 59% of whom died from distant metastasis. The 10‐year DSS was higher in patients who received chemoradiotherapy than those who received IMRT alone for patients with high‐risk stage III disease, while there was no survival difference for patients with stage II and low‐risk stage III disease.

Conclusions

IMRT provides satisfactory long‐term survival for patients with NPC. Distant metastasis has been the most common reason for failure. Adding chemotherapy did not improve survival in patients with stage II and low‐risk stage III disease.

http://bit.ly/2TbRPR8

Polyethylene Glycol fusion associated with anti‐oxidants: A new promise in the treatment of traumatic paralysis

http://bit.ly/2CEnpli

Issue Information

http://bit.ly/2TbOWzG

Surgical anatomy of the parapharyngeal space: A multiperspective, quantification‐based study

Abstract

Background

Several surgical approaches to the parapharyngeal space (PPS) have been proposed. An objective description of advantages and limitations of the surgical routes is lacking.

Methods

Ten cadaver heads were dissected using the transnasal (medial, lateral), sublabial, transoral (transpharyngeal, transvestibular, transmandibular), transcervical (transcervical, transparotid, transmandibular, transmastoid), and type C and D infratemporal approaches. Neurovascular and musculoskeletal structures encountered were analyzed. A navigation‐based quantification of working volume and exposure of PPS compartments was accomplished.

Results

Transnasal approaches exposed the upper PPS, though with limited working volume. Transoral approaches exposed the middle PPS, minimizing neurovascular structures crossed. Only transcervical and skull base approaches exposed the entire PPS, exposing several neurovascular structures.

Conclusion

A tentative systematization of the surgical approach(es) to PPS in relation to different targets is provided: unicompartmental resection can be performed with a single, conservative access, whereas multicompartmental dissections frequently require a wider or multiportal approach.

http://bit.ly/2CGhw71

Secretory carcinoma of the major salivary gland: A provincial population‐based analysis of clinical behavior and outcomes

Abstract

Background

Our aim was to identify the number of cases of secretory carcinoma (SC) of the major salivary gland in a population‐based cohort and review its clinical behavior with long‐term follow‐up.

Methods

All malignant salivary gland tumors (MSGTs) diagnosed between 1980 and 2014 were assessed for histological features compatible with SC and 140 were selected for further analysis.

Results

Twenty two new cases of SC were identified, 19 of which were originally classified as acinic cell carcinoma, and 3 as adenocarcinoma, not otherwise specified (NOS). Lymph node involvement was less common in SC tumors (5%) than in the control group (11%). Disease recurrence was seen less frequently in SC (9%) than the control group (20%). Mean disease‐free survival was 192 months for SC compared with 162 months for controls (P = 0.15).

Conclusion

The clinical course of SC is typically indolent with a low risk of relapse not significantly different from other low‐grade MSGT.

http://bit.ly/2TkULLz

Atypical Asphysia

http://www.jfsmonline.com/article.asp?issn=2349-5014;year=2018;volume=4;issue=4;spage=233;epage=237;aulast=Cao

Forensic investigation of atypical asphysia

Zhe Cao¹, Zhiyuan An², Xiaoning Hou¹, Dong Zhao^3
1 Anshan Public Security Bureau, Anshan, China
² Key Laboratory of Evidence Science (China University of Political Science and Law), Ministry of Education, China, Collaborative Innovation Center of Judicial Civilization, China
³ Key Laboratory of Evidence Science (China University of Political Science and Law), Ministry of Education, China, Collaborative Innovation Center of Judicial Civilization; Key Laboratory of Forensic Genetics of Ministry of Public Security, Institute of Forensic Science, Ministry of Public Security, Beijing, China

Correspondence Address:
Dr. Dong Zhao
25 Xitucheng Road, Haidian, Beijing 100088 
China

Abstract

Smothering, choking, confined spaces, traumatic asphyxia, positional asphyxia, and other kinds of atypical mechanical asphyxia are not rare in forensic practice. However, these are not commonly well demonstrated in forensic monographs worldwide. The authors researched related works and literatures and summarized these with a view to contribute to the existing teaching resources and provide help to forensic practitioners who are involved in scene investigation and identification of such deaths.

Keywords: Asphyxia, forensic pathology, forensic medicine

Introduction

Death caused by compression of the neck, such as from hanging, strangling, or throttling, is termed "mechanical asphyxia" and usually has obvious physical findings. However, asphyxias that result from no direct pressure on the neck vessels or trachea, lack typical morphological changes, or result in minimal damage are called "subtle asphyxias"^[1] or "atypical mechanical asphyxias," used in this article. Atypical mechanical asphyxias include smothering, choking, environmental hypoxia, traumatic asphyxia, and positional asphyxia, among others.

Smothering

Smothering is a form of asphyxia death caused by obstructing the mouth and nose with hands, airtight papers, soft textiles, or the weight of one's own head.^[2]

Smothering can be seen in homicidal or suicidal cases. Homicidal smothering is common in infants, older adults, and people who are unconscious or have restricted motion due to fabric bundling, disease, poisoning, or intoxication. Homicidal smothering can also result when there are significant physical power differences between a perpetrator and victim.^[3],[4],[5] Suicidal smothering is common in psychiatric patients; an example includes wrapping tape around one's mouth, nose, or the entire face.^[6] Smothering can also occur accidentally. For example, adults who are unconscious or paralyzed because of drunkenness, epilepsy, drug overdose, or having another disease might accidentally asphyxiate themselves. Similarly, for an infant lying face down on an airtight mattress or pillow, the weight of the infant's head might obstruct, distort, and occlude his or her mouth and nose, leading to suffocation. In a third example, sleeping infants with clothes or bedding covering their faces are at an increased risk of suffocation.^[1],[2]

In general, it is difficult to identify a case of smothering during forensic scene examination because physical findings are nonspecific.^[7],[8] If smothering is suspected, there may be local signs of pressure on the face.^[2],[3] In adults, with even slight resistance, signs include skin exfoliation from fingernails; contusions on the nose, cheeks, or chin from fingers; bleeding and skin tears corresponding to the teeth in the oral mucosa; and intramuscular bleeding at the mandibular margin. Nasal deformation is also considered a sign of smothering, but can be caused by emergency tracheal intubation.^[3],[5],[7] In infants and adults who are unable to physically resist during asphyxiation, physical damage is difficult to detect.^[3] Of note, a body in the prone position concentrates pressure on the face, preventing accumulation of blood into the compressed skin around the mouth and nose, leading to the formation of distinct pale areas caused by the absence of pooled blood. It is, therefore, important not to assume that pale areas such as these have resulted from indentation by smothering.^[2]

Without positive physical findings in smothering cases, scene investigation plays a decisive role. Pillows and bedding should be examined for blood or lipstick.^[5],[9] For suspected cases of smothering, even if postmortem changes are obvious, suspicious skin lesions should be biopsied for histological examination.^[5] In cases of smothering by textiles, the mouth, nasal cavity, and airways should be examined for inhaled fabric fibers. Fibers in the trachea indicate that a patient may have been alive during smothering.^[8]

Gagging generally involves placing fabric in a victim's mouth to prevent yelling; the fabric gradually becomes soaked with saliva, and if airtight, will lead to suffocation. Another form of gagging involves placing tape over the mouth or nose, which results in trapped mucus production that eventually leads to suffocation. Obstruction of the nasopharynx by objects in the oral cavity may also lead to gagging and subsequent death.^[2] Usually, suspected gagging is confirmed when blocking objects are found, not by any specific physical signs of asphyxia.^[3]

Choking

Choking refers to upper respiratory tract blockage by a foreign body leading to suffocation. The foreign body is usually lodged between the larynx and trachea.^[10],[11] Death may result from simple hypoxia; however, many deaths occur quickly before the onset of hypoxia. Studies have found that, even in cases in which the airway is not completely blocked, death often occurs, likely from neurogenic-induced cardiac arrest.^{[2],[9],[11],[12]}

Choking is almost always accidental, with cases of homicide and suicide relatively rare.^[1],[11] For infants, accidental choking most often occurs with foreign body ingestion; for adults, choking most often occurs with food.^[1],[11] Victims in homicidal choking cases are most likely to be older adults, infants, young children, people who are unconscious, or persons debilitated by illness or intoxication. Suicidal choking most often occurs in patients with psychosis or prisoners in jail.^[1]

Evidence of coughing helps eliminate choking as a cause of death because it signifies that the respiratory tract was open during upper respiratory blockage.^[3] Computed tomography imaging can provide information before an autopsy on the location of a foreign body and can help inform an autopsy plan.^[13] Few physical findings are generally seen in choking deaths, so the discovery of a foreign body in the airway, a detailed clinical history, descriptions of the death environment and any resuscitation attempts, and exclusion of other causes of death are critical when forming a conclusion.^{[1],[9],[11],[12]} If the foreign body shifts during resuscitation or otherwise is moved, clinical history might be the only evidence.^[3],[13]

Foreign bodies blocking the airway leading to choking generally belong to the following categories.^[2]

Foreign objects

Attackers may put a towel or sock into the victim's mouth to prevent shouting; this can cause choking and gagging.^[3] In another example, people may inhale sand, piles of gravel, or piles of soil when they fall on them, causing respiratory blockage and resulting in choking death. This scenario may occur accidentally at a construction site, during a traffic accident, or in children playing in or eating sand.^[3],[14]

Acute obstruction

Acute allergy, steam stimulation, heat inhalation, and acute inflammation may cause swelling of the throat organs, including the epiglottis, tonsils, or glottis, leading to choking. Trauma in the anterior or lateral cervical neck structures can also result in severe swelling of the respiratory tract from bleeding and edema.^[1],[2],[7] Tumors, polyps, or cysts can also block respiration, leading to choking.^{[1],[10],[11]}

Foods

The most common foreign bodies causing choking death in adults are foods.^[10] Susceptible factors include old age, neuromuscular disease, poor dentition leading to chewing problems, consumption of alcohol or other central nervous system depressants weakening the gag reflex, or other neurological or mental illness (of which poor dentition is an important risk factor).^{[1],[11],[12],[13]} Of patients with mental illness, those with schizophrenia are most likely to choke on food, possibly from a propensity to swallow incompletely chewed food.^[11] The majority of adult choking cases occur at patients' homes, nursing homes, or mental hospitals, and often take place suddenly during meals.^[1]

When a sudden death occurs while eating or soon after, the possibility of choking must be considered. A search for a blocked airway should be initiated, but in addition, the investigator should also consider factors that could have aggravated the choking episode. Therefore, quality and number of teeth, food debris in the esophagus – which can cause tracheal obstruction from the external oppression – and exclusion of neurological diseases and intoxication are all important when evaluating sudden death during a meal.^{[1],[9],[11],[12]}

It is typical for gastric contents to be present in the throat, trachea, and bronchi after death, caused by reflux or shifting of contents. This is a common postmortem phenomenon, found in 20%–25% of routine examinations. As a result, if a small amount of gastric content is found in the respiratory tract, this does not mean that choking had occurred; however, if the throat or airway is completely blocked by gastric contents, choking can be concluded.^[2],[3],[13] The inhalation of gastric contents is more common in people who are unconscious.^[1]Importantly, there is no reliable way to distinguish natural food reflux early in the dying process from true inhalation while alive, unless the inhalation occurred during a clinical procedure or another person witnessed the event. In most cases, in the absence of hard evidence, it is unreasonable for forensic officers to conclude that the inhalation of gastric contents is secondary to choking death.^[2]

Environmental Hypoxia

Environmental asphyxiation is usually caused by a lack of oxygen in the local environment,^[1],[2],[3] and is almost always accidental. Oxygen deficiency can occur secondary to breathing exercises, microbial consumption, activities related to industrial work (such as welding), environmental chemical reactions (such as rust), absorption by chemical substances (such as activated carbon), and presence of toxic gases (such as propane, nitrogen, and methane).^[1],[2],[3] An atmospheric oxygen concentration below 5%–10% will cause death in a few minutes, and a concentration of carbon dioxide higher than 10% is lethal.^[1] In some cases, death occurs before the onset of hypoxia, and is secondary to overexcitement of the body's chemical sensing system, which causes parasympathetic nervous system-mediated cardiac arrest.^[2]

In hypoxia-asphyxia deaths caused by low atmospheric oxygen levels, physical findings are usually absent,^[2] making elucidation of the specific cause of death difficult. Investigators must carefully analyze the environment and exclude other causes of death to conclude environmental hypoxia-asphyxia.^[3] Measurements of toxic gases and oxygen concentrations in the air, as well as postmortem analysis of blood and tissues, should be performed; in addition, scene simulations may be required.^[1]

As a type of environmental hypoxia-asphyxia, plastic bag suffocation is often used as a suicide technique in Western countries. This method is common in young men and elderly women.^[15] Some people even use the propane, ether, or helium gas along with the plastic bag. Plastic bag suffocation deaths can also occur accidentally or unexpectedly, such as during sexual asphyxia, children playing with plastic bags, and other occurrences.^[1] It is very rare for the use of plastic bags to result in death; however, it is more likely in cases in which the victim is unconscious, or when there is a large difference in strength between the perpetrator and victim.^[16]

Plastic bag suffocation often occurs rapidly with few physical signs;^[1],[2] however, in a small number of cases, marks on the neck are present corresponding to the areas of bag bundling (such as from a rubber band), or there may be signs of prior injury, such as wrist cutting or abuse.^[1],[2] It is a common misconception that the postmortem presence of moisture in the plastic bag confirms that the bag was placed on a breathing human; water droplets form as gas evaporates from the skin, nose, and mouth even if the person was previously deceased.^[2]

Because there are usually no specific physical findings, it is difficult to identify cases of plastic bag suffocation unless the bag is over the head at the time of scene investigation or autopsy.^[2] If the plastic bag is removed before forensic workers see the corpse, they will not be able to determine the cause of death through forensic examination, and may even conclude that a natural death occurred. Therefore, to identify such cases, forensic workers must pay careful attention during scene exploration and investigation.^{[1],[3],[9],[16]} If necessary, forensic workers can conduct simulations under close monitoring in a protected environment, which can help to pinpoint a cause of death through analysis of time measurements.^[4],[6],[17] Specimens collected from the blood, lungs, liver, or other organs for poison analysis should be extracted and stored in a sealed empty bottle along with a plastic bag,^[2],[7],[16] frozen, and delivered promptly.^[1]

Traumatic Asphyxia

Traumatic asphyxia refers to the compression of the chest or abdomen by massive mechanical forces resulting in thoracic fixation – expansion of thoracic and lower phrenic muscles – leading to respiratory disturbance and death by asphyxiation.^[2]

Traumatic asphyxia is common in the following types of accidents: motor vehicle compression or extrusion during traffic accidents; pinning from building collapse, falling rocks, or other objects; trampling by a crowd; compression while standing in a crowded population from sudden external forces; compression by fallen tools or furniture; and compression of infants and children while sleeping with parents (overlaying asphyxia).^[1],[2],[18] There are also reports of homicide resulting from a perpetrator kneeling or sitting on the chest of a victim.^[19]

The pathological features of traumatic asphyxia are usually quite specific. These include prominent facial and nuchal hyperemia and swelling; numerous petechial hemorrhages on the face or conjunctiva; subconjunctival hemorrhage and edema; and nasal bleeding. In general, a person who dies from traumatic asphyxiation often appears strangled with features extending down to the neck, with no signs of local damage.^{[2],[20],[21]}

However, physical features such as these are not always visible. Studies have shown that, in up to 10% of cases, no petechial hemorrhages are seen on the face or conjunctiva. The reason for this is unclear, but may be related to rapidness of death, lack of obvious chest compression or vagus nerve stimulation, lack of occlusion of the epiglottis, or concurrence of both left heart and right heart impairment at the time of chest compression.^{[1],[18],[20],[21]} On gross examination, lungs may have a purplish red color, congestion, or subserous bleeding with or without obvious expansion of the right heart or superior vena cava; sometimes, there is no evidence of trauma despite severe direct external compression on the chest and abdomen.^{[1],[2],[3],[9]}

Traumatic asphyxia is a diagnosis of exclusion. In addition to supporting evidence from a scene investigation, suffocation death should only be considered after excluding fatal injuries and poisoning.^[1],[9],[21]

Overlaying asphyxia is a special form of traumatic asphyxia, often secondary to nasal compression. Physical examination findings are usually absent, so overlaying can be difficult to determine unless the same-bed sleeper admits to crushing the infant or child. Overlaying asphyxia is sometimes attributed to sudden infant death syndrome, so it is important to examine adults' and children's clothes and bedding carefully as well as the scene.^[1],[3],[22]

Positional Asphyxia

Positional asphyxia refers occurrences in which respiration is compromised from splinting of the chest or diaphragm preventing normal respiration, or occlusion of the upper airway due to abnormal positioning of the body.^[23] Positional asphyxia is almost always an accident, during which the victim cannot extract himself or herself from a specific position or small space. The victim may be further impaired by alcohol or drug intoxication, weakness, neurological disease, or fabric bundling. Common examples of positional asphyxia include limbs tied behind the back while in a prone position (may be performed for restraint by police or psychiatrists for suspects or patients); head-down position (inversion of the body, or head hanging down off the edge of a bathtub); jack-knife position (upper body significantly curved from the waist down); bundled thoracic or abdominal horizontal sling (e.g., a young girl wearing a belt hanging by the abdomen on a swing); excessive flexion or extension of the neck (e.g., during a motor vehicle accident); lack of chest wall expansion in a restricted space (wedging); and a person sandwiched between the wall and the mattress after falling off the bed.^{[1],[2],[3],[4],[5],[6],[7],[24]} A typical case of postural asphyxia involves a drunken person who collapses into a narrow space, excessively distorting the neck and hindering breathing, leading to death.^[9]

Cause of death from positional asphyxia often results from reverse suspension of the body such that the movement of the chest wall is restricted by intra-abdominal organs compressing the diaphragm. This prolongs inspiration, and eventually results in respiratory muscle fatigue, leading to slowed movement of the chest wall and subsequent hypoxia. Venous return is effectively limited, and blood flow to the brain is shifted, decreasing blood flow and further aggravating respiratory muscle fatigue; eventually, the heart stops.^[1] Positional asphyxia does not require reversal of the entire body; fatal asphyxia may result from the reversal of torso position, excessive flexion of the neck, or pressure on one's face, such as in an intoxicated person whose face is pressed to the floor.^[25] The difference between traumatic asphyxia and positional asphyxia is whether the chest and abdomen are compressed by external forces. If chest compression is from an external source, he or she should have been died from traumatic asphyxia. If a deceased person is found in a specific position or restricted space that limits chest activity, the person should have been died from positional asphyxia.^[1],[23]

Positional asphyxia can be identified by the following criteria: The body position is consistent with restricted or disordered respiration; scene investigation or historical investigation identifies that an accident had occurred; the deceased person cannot change his or her position for some reason; and other obvious natural or violent causes of death are excluded. A diagnosis of accidental positional asphyxia mainly depends on the evidence obtained from the scene environment.^[24],[25] Some forensic investigators believe that, if another disease is present, then either the cause of death is not associated with positional asphyxia, or the onset of the disease makes the deceased patient prone to positional asphyxia.^[23] It should be noted that alcohol consumed by a patient with positional asphyxia may be metabolized. Thus, even if the concentration of alcohol in the blood or urine is very low or negative, the possibility of positional asphyxia cannot be ignored.^[24]

Wedging is a special form of positional asphyxia, commonly seen in infants and young children whose body or head are compressed in a narrow space. The chest wall is fixed, resulting in airway obstruction that results in asphyxia. Wedging usually occurs between a mattress and wall or mattress and furniture or baby crib. It is most common in infants aged 3–6 months, intoxicated adults, or comatose patients who accidentally fall between a mattress and wall, leading to death. Physical findings of wedging are usually absent.^[1],[22]

Acknowledgments

This study was supported by the Open Project of Key Laboratory of Forensic Genetics, Ministry of Public Security (2017FGKFKT05), Program for Young Innovative Research Team from China University of Political Science and Law (2016CXTD05), and Project of Interdisciplinary Science Construction-Forensic Psychology from China University of Political Science and Law.