Facial Palsy after Orthognathic Surgery: Incidence, Causative Mechanism, Management, and Outcome.

BACKGROUND: Facial palsy after orthognathic surgery is an uncommon but serious complication causing dissatisfaction and affecting quality of life. The occurrence could be underreported. Surgeons need to recognize this issue regarding the incidence, causative mechanism, managements, and outcome. METHODS: A retrospective review of orthognathic surgery records between January of 1981 and May of 2022 was conducted in the authors' craniofacial center. Patients who developed facial palsy after the surgery were identified, and demographics, surgical methods, radiologic images, and photographs were collected. RESULTS: A total of 20,953 sagittal split ramus osteotomies (SSROs) were performed in 10,478 patients. Twenty-seven patients developed facial palsy, resulting in an incidence of 0.13% per SSRO. In a comparison of SSRO technique, the Obwegeser-Dal Pont technique using osteotome for splitting had higher risk of facial palsy than the Hunsuck technique using the manual twist splitting ( P < 0.05). The severity of facial palsy was complete in 55.6% of patients and incomplete in 44.4%. All patients were treated conservatively, and 88.9% attained full recovery in a median duration of 3 months [interquartile range (IQR), 2.75 to 6 months] after surgery, whereas 11.1% attained partial recovery. Initial severity of facial palsy predicted the timing of recovery, with incomplete palsy patients having faster median recovery (3 months; IQR, 2 to 3 months) than the complete palsy patients (6 months; IQR, 4 to 6.25 months) ( P = 0.02). CONCLUSIONS: The incidence of facial palsy after orthognathic surgery was 0.13%. Intraoperative nerve compression was the most likely causative mechanism. Conservative treatment is the mainstay of therapeutic strategy, and full functional recovery was anticipated. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, IV.

Prospective Assessment of Risk Factors Influencing Facial Nerve Paresis in Patients after Surgery for Parotid Gland Tumors.

Background and objectives: Facial weakness is the most important complication of parotid gland tumor surgery. The aims of this study are as follows: (1) assessment of the prevalence of postparotidectomy facial nerve dysfunction; (2) clinical and electrophysiological assessment of the facial nerve function before parotidectomy and at 1 and 6 months postoperatively; (3) assessment of the association of postoperative facial palsy with selected risk factors; and (4) assessment of the correlation between the results of clinical and neurophysiological assessments of facial nerve function. Materials and Methods: This study comprised 50 patients (aged 24-75 years) who underwent parotidectomy at the Department of Otolaryngology and Laryngological Oncology in Zabrze, Poland between 2015 and 2017. The evaluation included neurological, clinical and electrophysiological assessments of the facial nerve prior to surgery and at 1 and 6 months postoperatively. Results: No facial palsy was found preoperatively or 6 months postoperatively. Facial nerve dysfunction was found in 74% of patients 1 month postoperatively. In most cases (54%), paresis was mild or moderate (House-Brackmann grades II and III). The results of electrophysiological tests before parotidectomy were either normal or showed some mild abnormalities. We found a statistically significant correlation between the clinical assessment of the facial nerve function (based on the House-Brackmann scale) one month postoperatively and the latency of the CMAP response from the orbicularis oculi and orbicularis oris muscles. In all three studies, a statistically significant correlation was found between the amplitude of the compound muscle action potential (CMAP) of the orbicularis oris muscle and the degree of facial nerve weakness. Conclusions: The factors that may influence the risk of postoperative facial nerve paralysis (prolonged surgical time and the size and location of the tumor other than in the superficial lobe only) may indirectly suggest that surgery-related difficulties and/or surgeon experience could be crucial to surgery safety.

Incidence and Management of Facial Paralysis After Skull Base Trauma, an Administrative Database Study.

OBJECTIVE: Report the incidence of and treatment patterns for facial nerve palsy after skull base fracture. STUDY DESIGN: Retrospective cohort study. SETTING: IBM MarketScan Commercial Database (2006-2019). PATIENTS: Human subjects with skull base fracture, per International Classification of Diseases-9th and 10th Revisions-Clinical Modification diagnosis codes. MAIN OUTCOME MEASURES: The primary outcomes were the incidence and median time to facial nerve palsy diagnosis within 30 days of skull base fracture. Secondary outcomes were treatments (corticosteroids, antivirals, facial nerve decompression, botulinum toxin, and facial reanimation), demographics, and rates of hearing loss, vertigo, tympanic membrane rupture, cerebrospinal fluid leak, comorbidities, and loss of consciousness. RESULTS: The 30-day incidence of facial nerve palsy after skull base trauma was 1.0% (738 of 72,273 patients). The median (95% confidence interval [CI]) time to diagnosis was 6 (6-7) days, and only 22.9% were diagnosed within 1 day. There were significantly higher rates (risk difference, 95% CI) of hearing loss (26%, 22-29%), tympanic membrane rupture (6.3%, 4.5-8.1%), cerebrospinal fluid leak (6.4%, 4.5-8.3%), comorbidity (14%, 10.4-17.6%), and loss of consciousness (24.3%, 20.7-27.9%). Loss of consciousness was associated with longer median (95% CI) time to facial nerve palsy diagnosis: 10 (9-10) days. Corticosteroids were the most common treatment but only reported for less than one-third of patients. Only eight patients underwent facial nerve decompression. CONCLUSIONS: Facial nerve palsy after skull base fracture is associated with higher comorbidity, and the diagnosis is often delayed. Few patients were treated with surgery, and there are inconsistencies in the types and timing of treatments.

Prospective Assessment of Intraoperative Facial Nerve Monitoring in Patients Undergoing Partial Parotidectomy.

The most significant complication of parotid gland tumor surgery is facial weakness. This study compares the occurrence of transient facial palsy in patients with parotid gland tumors who underwent surgery without monitoring to those who underwent surgery with monitoring. The study's aim was to investigate facial nerve function in patients undergoing parotidectomy as well as the effect of intraoperative facial nerve monitoring and the effect of certain risk factors on the surgery and onset of postoperative facial palsy. This prospective study included 100 patients who underwent parotidectomy. The study cohort was divided into two groups. Group I included 50 patients who underwent surgery without neuromonitoring and group II included 50 patients who underwent surgery with neuromonitoring. The neurological assessment was conducted using the House-Brackmann scale. Preoperatively and one month postoperatively, electroneuronography (ENoG) and blink reflex tests were done. The analyses showed a significant reduction of the compound muscle action potential (CMAP) amplitude of the orbicularis oculi and orbicularis oris muscles and prolonged R1 and R2 blink reflex latencies 1 month after surgery. On neurological and electrophysiological studies, the rate of postoperative transient facial nerve dysfunction was significantly different between the groups. Significantly more patients, operated with use of facial nerve monitoring, presented postoperatively normal nerve function (i.e., House-Brackmann grade I) compared to those who underwent surgery without monitoring (78% and 26%, respectively; p < 0.001). Monitoring had a statistically significant impact on the prevalence of facial nerve conduction disorders in patients who underwent surgery, according to the blink reflex and ENoG studies. The duration of the surgical procedure was not affected by monitoring in any way. The clinical evaluation of facial nerve function (House-Brackmann scale) and some ENoG results 1 month after surgery were found to have a significant correlation. To summarize, using monitoring considerably reduced the negative impact of local factors and the prevalence of transient facial nerve palsy.

A Century in Review: Medicolegal Implications of Facial Nerve Paralysis.

Importance: It is important to recognize factors that may mitigate the risk of a potential lawsuit and increase knowledge and awareness of physicians. Objective: To evaluate and characterize facial nerve paralysis litigation claims and related potential causes. Design, Setting, and Participants: These data were extracted from the two main computerized legal databases: WestLaw and LexisNexis. The data were queried on April 2, 2020. The records from 1919 to 2020 were obtained from a population-based setting. A total of 186 cases were included. Data were gathered for all alleged cases of facial nerve paralysis. Main Outcomes and Measures: There was a continuous rise in the amount of malpractice payments with the highest mean amount being in the past decade. Results: From 1919 to 2020, a total of 186 malpractice cases for facial nerve damage were identified. A total amount of $89,178,857.99 was rewarded to plaintiffs in 66 cases. The mean amount of paid malpractice claim was $1,351,194.80. Improper performance/treatment was the most common reason for alleged litigation (n = 97). This was followed by misdiagnosis/delayed diagnosis (n = 47), and failure of informed consent (n = 34). The highest number of malpractice claims with a total of 53 cases was from 1991 to 2000. The highest mean amount per payment was in the past decade (2011-2020) with a mean of $3,841,052.68. Conclusions and Relevance: Over the past century, improper performance/procedure, delayed/misdiagnosis, and failure of informed consent were the most common reasons for litigations related to facial nerve paralysis.

Assessment of anti-HSV antibodies in patients with facial palsy in the course of neuroborreliosis.

AIM: There are many causes of facial nerve palsy. The most common causes are neuroborreliosis (NB), idiopathic paralysis or Herpes simplex virus (HSV) reactivation. The aim of this study was to characterize patients with facial palsy in the course of NB and to determine whether HSV-1 reactivation takes place during the acute phase of NB. METHODS: A retrospective analysis of 66 patients with facial nerve palsy was performed. In 38 patients, facial palsy was caused by Borrelia burgdorferi sl infection. Immunological tests for HSV-1, tick-borne encephalitis virus and B burgdorferi sl in serum and cerebrospinal fluid (CSF) were performed. RESULTS: In this analysis, 55.2% of NB patients had right nerve palsy and 21% bilateral palsy; 15.8% of patients had erythema migrans (EM). Lymphocytic meningitis was diagnosed in 92% of patients and Bannwarth's syndrome was diagnosed in 47% of patients. IgM anti-HSV-1 antibodies were detected in four patients with NB and two patients with facial nerve palsy of other origin. IgM anti-HSV-1 antibodies were detected in the CSF of three patients (7.9%) with NB, and one of them had bilateral VII paresis and EM simultaneously. Treatment with ceftriaxone or doxycycline led to complete recovery. CONCLUSIONS: Neuroborreliosis should always be considered as a cause of peripheral facial nerve palsy. Peripheral facial nerve palsy is a significant symptom in the course of NB, especially in patients accompanied by meningitis. Pathomechanism of facial nerve paresis has not been well explained so far and may depend on two independent mechanisms in NB, including HSV-1 reactivation.

Acute Otitis Media and Associated Complications in United States Emergency Departments.

OBJECTIVE: Complications due to acute otitis media (AOM), while rare, are associated with significant morbidity and are not well characterized from an epidemiological perspective. We analyze the pattern of presentation and emergency department (ED) utilization in patients with AOM and associated complications. STUDY DESIGN: Retrospective analysis of the Nationwide Emergency Department Sample (NEDS) from 2009 to 2011. SETTING: Emergency Department. PATIENTS: Patients who presented with a primary diagnosis of AOM or acute mastoiditis. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURES: NEDS was queried for patient encounters with a diagnosis of AOM or acute mastoiditis based on ICD-9 codes. Complications of severe infection, including petrositis, Gradenigo's syndrome, facial paresis, labyrinthitis, meningitis, intracranial abscess, venous sinus thrombosis, and cerebrospinal fluid leak, were assessed. Weighted estimates for demographics, types of complications, socioeconomic status, and trends over time were extracted. RESULTS: A weighted total of 5,811,127 ED visits were identified. The majority of patients were less than 18 years old (79.9%) with an average age of 10.1 years. Most were discharged (99.4%). There were 15,243 (0.26%) patients who presented with a complication. The most common complications were acute mastoiditis (0.16%), labyrinthitis (0.06%), and facial paresis (0.03%). Compared with patients with uncomplicated AOM, patients with complicated AOM were older (37 vs. 10-yr old), insured by Medicare (18% vs. 2.1%), and more likely to be admitted (43.6% vs. 0.4%) (p < 0.0001, for all comparisons). CONCLUSIONS: ED visits related to AOM or mastoiditis are common and complications are rare. An in-depth analysis on a national level is useful for assessing healthcare utilization trends.

Derivation and Validation of the Emergency Medical Stroke Assessment and Comparison of Large Vessel Occlusion Scales.

BACKGROUND: This study aims to develop a simple scale to identify patients with prehospital stroke with large vessel occlusion (LVO), without losing sensitivity for other stroke types. METHODS: The Emergency Medical Stroke Assessment (EMSA) was derived from the National Institutes of Health Stroke Scale (NIHSS) items and validated for prediction of LVO in a separate cohort. We compared the EMSA with the 3-item stroke scale (3I-SS), Cincinnati Prehospital Stroke Severity Scale (C-STAT), Rapid Arterial oCclusion Evaluation (RACE) scale, and Field Assessment Stroke Triage for Emergency Destination (FAST-ED) for prediction of LVO and stroke. We surveyed paramedics to assess ease of use and interpretation of scales. RESULTS: The combination of gaze preference, facial asymmetry, asymmetrical arm and leg drift, and abnormal speech or language yielded the EMSA. An EMSA less than 3, 75% sensitivity, and 50% specificity significantly reduced the likelihood of LVO (LR- = .489, 95% confidence interval .366-0.637) versus 3I-SS less than 4 (.866, .798-0.926). A normal EMSA, 93% sensitivity, and 47% specificity significantly reduced the likelihood of stroke (LR- = .142, .068-0.299) versus 3I-SS (.476, .330-0.688) and C-STAT (.858, .717-1.028). EMSA was rated easy to perform by 72% (13 of 18) of paramedics versus 67% (12 of 18) for FAST-ED and 6% (1 of 18) for RACE (χ2 = 27.25, P < .0001), and easy to interpret by 94% (17 of 18) versus 56% (10 of 18) for FAST-ED and 11% (2 of 18) for RACE (χ2 = 21.13, P < .0001). CONCLUSIONS: The EMSA has superior abilities to identify LVO versus 3I-SS and stroke versus 3I-SS and C-STAT. The EMSA has similar ability to triage patients with stroke compared with the FAST-ED and RACE, but is simpler to perform and interpret.

Objective assessment of the reliability of the House-Brackmann and Fisch grading of synkinesis.

The objective of this paper is to assess synkinesis associated with post paretic voluntary facial movements using the objective OSCAR method and to investigate the correlation between synkinesis and paresis to compare the objective results with the subjective scaling systems of Fisch and House-Brackmann. The development of an objective assessment of synkinesis with the OSCAR method is focused on the clinically most relevant eye-mouth and forehead-mouth synkinetic movements. Thirteen patients with unilateral facial paralysis and synkinesis of the University Hospital Zurich were examined. Two types of clinically relevant facial synkinesis were found: a maximal synkinesis and a relative synkinesis. Neither Synkinesis-Index correlates well with the underlying degree of global facial palsy. The relative Synkinesis-Index (rSI) correlates well with the subjective evaluation of synkinesis according to the Fisch Grading, but shows a poor correlation with the traditional House-Brackmann grading. Therefore a single scaling index combining the degree of facial nerve palsy and synkinesis is inappropriate and we propose the use of two independent scaling systems for the evaluation of facial palsy: one for the voluntary facial movements, the other for the involuntary synkinetic movements. The adequate evaluation of the post paretic face should include the results of both scaling systems.

[Facial palsy rehabilitation: Assessment before surgery]. / Réhabilitation de la face paralysée. Bilan préthérapeutique du patient.

A patient who needs a surgery for facial rehabilitation must have a complete assessment. The etiology of the facial palsy must be clear. It is necessary to have a MRI of the facial nerve for the statement of the initial pathology or to search a lesion on the nerve. The facial palsy must be definite which is depending of the delay of the palsy and the etiology. An electromyography must be done. The choice of the procedure depends on the delay of the palsy, the site on the nerve, the associated diseases and the opinion of the patient after a good explanation.

Congenital myasthenic syndrome due to choline acetyltransferase mutations in infants: clinical suspicion and comprehensive electrophysiological assessment are important for early diagnosis.

Congenital myasthenic syndromes are inherited disorders caused by various defects in neuromuscular transmission. Although the typical presentation is fatigable weakness with prominent cranial involvement, neonates can lack these hallmark manifestations, and in those with choline acetyltransferase gene mutations, basal electrophysiological testing can yield negative findings. The authors report the case of a male infant presenting at birth with oculomotor and bulbofacial weakness, hypotonia, clubfoot, and severe respiratory insufficiency. Electromyography showed myogenic signs, and basal repetitive nerve stimulation yielded negative findings. Since age 6 months, the infant had progressively improved, acquiring autonomous respiration. Prolonged subtetanic repetitive nerve stimulation disclosed a marked decremental response compatible with suspected congenital myasthenic syndrome with episodic apnea. Genetic testing identified 2 novel choline acetyltransferase mutations (R470X, F580C). Keeping a high clinical suspicion of this rare condition and undertaking early comprehensive electrophysiological assessments including prolonged repetitive nerve stimulation (10 Hz for 5 minutes) can expedite the diagnosis.

Aplasia of the cochlea: radiologic assessment and options for hearing rehabilitation.

OBJECTIVE: Hearing rehabilitation of patients with severe inner ear malformations remains controversial. Our objective was to describe the radiologic findings of aplasia of the cochlea (AC) and evaluate the existing therapeutic options in such patients. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Pediatric and adult patients with AC evaluated at our institution from 1995 to 2010. INTERVENTIONS: The precise radiologic findings were identified using high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) scans of the inner ear. In cases of auditory implantation on the AC side, the achieved outcome was recorded using categories of auditory performance (CAP). Related surgical aspects were analyzed. RESULTS: Twenty-three patients (28 ears) with AC were found. In 5 patients AC was bilateral. The remaining unilateral cases had contralateral normal ears (2 patients), cochlea hypoplasia (5 patients), common cavity (6 patients), incomplete partition Type I (4 patients), and atresia of the internal auditory canal (1 patient). Four patients (3 bilateral, 1 unilateral ACs) were treated with cochlear implants in ears with AC, and 1 patient underwent auditory brainstem implantation. All implanted patients achieved speech perception with limited vocabulary (CAP scores between 4 and 5). CONCLUSION: AC is defined as the total absence of the cochlea, with a present, although malformed, vestibule. Although a distinct auditory nerve was not seen in these cases of AC, results following cochlear implantation suggest functional cochlear nerve fibers in the remaining dysplastic inner ear structures. In selected cases, cochlear implantation may be a reasonable option for the habilitation of deafness associated with AC.

Validation of the Glasgow Facial Palsy Scale for the assessment of smile reanimation surgery in facial paralysis.

OBJECTIVES: To evaluate the Glasgow Facial Palsy Scale as a tool to assess facial reanimation surgery in facial palsy. Software analysis of digital video data is used to measure facial movements, comparing the affected to the normal side. We present the first use of the Glasgow Facial Palsy Scale following facial re-animation surgery. DESIGN: A comparison of the Glasgow Facial Palsy Scale against the Nottingham scoring system. Subjects undergoing unilateral surgical smile reanimation procedures were selected. Comparison was made with the Nottingham facial palsy scale and the House-Brackmann Scale pre- and postoperatively. SETTING: Patients were recruited in the facial palsy clinic of Canniesburn Plastic Surgery Unit, Glasgow. PARTICIPANTS: Seven consecutive patients were selected who were due to undergo unilateral facial reanimation. MAIN OUTCOME MEASURES: The difference in pre- and post-surgical facial movement as measured using the Glasgow Facial Palsy Scale with this value being compared to that obtained using the Nottingham scoring system. Note was also taken of the correlation with House-Brackmann system and clinical correlation. RESULTS AND CONCLUSIONS: Statistical analysis indicated a linear relationship between the Glasgow Facial Palsy Scale and the Nottingham System. The Pearson correlation test was used to confirm the relationship between the two methods giving a result of -0.587, which indicates significant correlation between the two methods. We conclude that the Glasgow Facial Palsy Scale is a standardised objective method of assessing the change in facial movement following smile reanimation surgery. We commend it as a useful tool to objectively assess surgical results in this challenging field.

Herpes simplex virus type 1 and Bell's palsy-a current assessment of the controversy.

Bell's palsy causes about two thirds of cases of acute peripheral facial weakness. Although the majority of cases completely recover spontaneously, about 30% of cases do not and are at risk from persisting severe facial paralysis and pain. It has been suggested that herpes simplex virus type 1 (HSV-1) may be the etiological agent that causes Bell's palsy. Although corticosteroid therapy is now universally recognized as improving the outcome of Bell's palsy, the question as to whether or not a combination of antiviral agents and corticosteroids result in a better rate of complete facial recovery compared with corticosteroids alone is now a highly contentious issue. The evidence obtained from laboratory studies of animals and humans that HSV-1 may be linked to facial nerve paralysis is first outlined. The discussion then focuses on the results of different clinical trials of the efficacy of antiviral agents combined with corticosteroids in increasing the rate of complete recovery in Bell's palsy. These have often given different results leading to opposite conclusions as to the efficacy of antivirals. Of three recent meta-analyses of previous trials, two concluded that antivirals produce no added benefit to corticosteroids alone in producing complete facial recovery, and one concluded that such combined therapy may be associated with additional benefit. Although it is probably not justified at the present time to treat patients with Bell's palsy with antiviral agents in addition to corticosteroids, it remains to be shown whether antivirals may be beneficial in treating patients who present with severe or complete facial paralysis.

Global assessment of outcomes after varying reinnervation techniques for patients with facial paralysis subsequent to acoustic neuroma excision.

OBJECTIVE: To determine whether there are objective and/or subjective differences in facial function, tongue function and quality of life in patients who have undergone 1) direct facial-to-facial (Primary, 4 patients), 2) direct facial-to-hypoglossal (End-to-End, 7 patients), 3) end-to-side facial-to-hypoglossal nerve anastomoses with sural nerve/greater auricular nerve interposition (End-to-Side with Interposition Graft, 7 patients), and 4) end-to-side facial-to-hypoglossal nerve anastomoses (End-to-Side, 7 patients) after acoustic neuroma excision. SETTING: Tertiary university referral center. STUDY DESIGN: Case series. METHODS: Twenty-five patients with complete facial paralysis after acoustic neuroma surgery who have also undergone 1 of 4 types of facial musculature reinnervation volunteered for the study. The mean duration of follow-up was 11.5 years (range, 1-25 yr). Each patient was globally assessed using the Sunnybrook Facial Grading scale (objective), Facial Disability Index (subjective), Oral-Pharyngeal Disability Index (subjective), Tongue Movement/Muscle symmetry (objective), and short-form SF-36 quality-of-life index (subjective). RESULTS: Patients who underwent direct facial-to-hypoglossal anastomosis had generally poorer outcomes some of which were statistically significant (p < 0.05) in some components of the Oral-Pharyngeal Disability Index. All of these patients had reduced lateral tongue movement as well as ipsilateral tongue atrophy. There was no significant difference in the Sunnybrook Facial Grading scale scores in those patients in whom end-to-side interposition reinnervation surgery was performed compared with those in whom direct end-to-side anastomosis surgery was performed. CONCLUSION: Complete sacrifice of the ipsilateral hypoglossal nerve does present with clinically and statistically significant morbidity in patients. Facial function is statistically similar in patients who underwent an end-to-side anastomosis with or without an interposition graft. These findings suggest thatin the setting of the posttranslabryinthine approach, the technicallyeasier interposition graft procedure is not acompromise.

A rare case of a glass foreign body in the parapharyngeal space: pre-operative assessment by contrast-enhanced CT and three-dimensional CT images.

The parapharyngeal space is an infrequent area for foreign bodies to lodge. However, the presence of trauma or inflammation near or within the space is dangerous because of its anatomical proximity to the bifurcation of the maxillary artery, carotid artery and jugular vein. We encountered a rare case, when a glass flask burst, in which intraparotid damage to the facial nerve was seen, as well as a glass foreign body lodged in the parapharyngeal space close to the above named great vessels. We emphasise the usefulness of contrast-enhanced CT and three-dimensional CT images for pre-operative evaluation of the locational relationship between the foreign body and great vessels in the parapharyngeal space.

Tissue welding forceps usage in superficial parotidectomy: a clinical assessment.

Tissue welding forceps (TWF) have been used effectively in a number of surgical procedures including blood vessel harvesting and tonsillectomy. Our objective was to assess the safety and efficacy of TWF usage in superficial parotidectomy. We performed a retrospective review of 25 patients between November 2002 and July 2006 who underwent superficial parotidectomy using TWF. The inpatient and outpatient records were reviewed for diagnosis, operative times, estimated blood loss, and postoperative facial paresis. Only one of the 25 patients (4%) who underwent superficial parotidectomy using TWF had transient postoperative facial weakness and no procedure had blood loss of greater than 150 cc. This initial evaluation suggests that use of TWF is safe in superficial parotidectomy and may help reduce the development of postoperative facial paresis.