The effect of various muscle transfer procedures on eye closure and blinking in longstanding facial palsy patients.

BACKGROUND: Facial palsy causes paralytic lagophthalmos, which remarkably deteriorates a patient's quality of life. In cases where denervation time is over 18-24 months (longstanding facial palsy), a free or pedicled muscle transfer is needed to replace the denervated orbicularis oculi muscle. PURPOSE: The purpose of this systematic review is to investigate the effect of various eye sphincter substitution procedures (free or pedicled muscle transfers) in longstanding facial palsy patients on eye closure and blink. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we performed a systematic review of the Embase, Medline, Web of Science and Cochrane Library databases and Google Scholar. Our literature search yielded 4322 articles. Following a full-text review, 4 retrospective cohort studies and 21 case series were selected for this review. Meta-analyses using R package meta (version 6.5-0) were conducted. MAIN FINDINGS: All free and pedicled muscle transfers in this review showed an improvement in the scores and measurements on eye closure and blink. The pedicled temporalis muscle transfer was the procedure most commonly performed as eye reanimation surgery and showed consistent good results. Using the random effects model, the pooled effect of mean difference in lagophthalmos after gentle eye closure post-operatively versus pre-operatively (mm) in patients who received a pedicled (temporalis) muscle transfer was -6.19 (I2 = 85%, 95% CI: -7.89; -4.49) whereas it was -4.11 (I2 = 85%, 95% CI: -7.26; -0.95) for free (gracilis or platysma) muscle transfers. The pooled proportion of patients with complete eye closure after surgery was 0.69 (I2 = 49%, 95% CI: 0.54; 0.82) in patients who received a pedicled (temporalis) muscle transfer and 0.40 (I2 = 74%, 95% CI: 0.13; 0.74) in patients who received a free (platysma) muscle transfer. CONCLUSIONS: Unlike smile reanimation, dynamic eye closure and blink restoration are rather neglected topics in facial reanimation. The pedicled temporalis muscle transfer is often recommended as the first treatment of choice for eye reanimation in longstanding facial palsy patients since it is a reliable, straightforward procedure, that does not require complex microsurgery. However, with the advancements in the field of microsurgery, free muscle transfers are promising therapies, which may regenerate voluntary and spontaneous blinking.

Quantitative Evaluation of Palatal Lengthening After Cleft Palate Repair When a Buccal Flap Is Routinely Combined With Furlow's Z-Plasty.

INTRODUCTION: The use of a buccinator myomucosal flap in combination with Furlow's Z-plasty during primary and secondary palatal repairs has been proposed by many authors to overcome some of the limitations of Furlow's technique. However, there have been no studies that quantitatively measured the effective palatal lengthening when the buccal flap is added. PATIENTS AND METHODS: The buccal flap is routinely used during primary palate repair in order to fill the gap between the hard palate and reoriented palatal muscle sling. The soft palatal length was measured in the midline from the posterior edge of the hard palate to the base of the uvula. All patients were measured before starting the surgery and just after palatal closure in the standard position for cleft palate repair. RESULTS: Seventy-three patients with cleft palate who were candidates for primary repair were included. The mean age at the time of operation was 11.4 ± 3.5 months. The mean preoperative palatal length was 21.36 ± 3.529 mm, whereas the mean postoperative palatal length was 29.64 ± 4.171) mm. The mean palatal length change was 8.29 ± 2.514 mm (P < 0.000). CONCLUSIONS: The Combined use of a buccinator myomucosal flap with modified Furlow's Z-plasty in primary cleft palate repair has proven effective for palatal lengthening and achieved tensionless closure without the need for relaxing incision. It also provided a pliable soft tissue attachment of the palatal muscles to the hard palate allowing for better muscle function and mobility.

Modified Buccal Myomucosal Flap Closure of Large Anterior Palatal Oronasal Fistulas.

SUMMARY: Large oronasal palatal fistulas can be challenging to reconstruct. The authors present a modified buccal myomucosal flap repair technique and review intermediate-term outcomes. In this technique, large anterior palatal fistulas are closed in two layers. First, apposing nasal turnover flaps of vomer mucosa medially and nasal wall mucosa laterally are approximated. Second, a posteriorly based buccal flap incorporating full-thickness buccinator muscle and overlying mucosa is transposed with interposition of the flap in the retromolar trigone and lateral palate to preserve dental occlusion. Consecutive patient cases performed in low-resource settings were reviewed and outcomes reported. Among eight subjects aged 3 to 22 years, with average defect size of 2.5 cm2 (range, 0.8 to 3.5 cm2), the flap was viable in all cases and required revision or pedicle division in only two patients (25 percent); all patients showed symptom improvement. The modified buccal myomucosal flap shows promising intermediate-term results as a single-stage reconstruction suitable to a wide patient age range, low airway/anesthetic risk, reliable functional outcomes, and low comorbidity.

Facial artery-based islanded myomucosal and bone flaps in head and neck reconstruction.

This article aims to illustrate various applications of facial artery-based islanded myomucosal (iFAMM) and osseous/osteo-myomucosal flaps (iFOMM) in head and neck reconstruction. A retrospective analysis of 75 patients who underwent the reconstruction of various head and neck mucosal defects with iFAMM/iFOMM in a tertiary head and neck cancer department from May 2015 to May 2019 was performed. The patients had surgery for cancer, which involved the oral tongue, floor of mouth, oropharynx, lower alveolus, larynx, hypopharynx, cricopharynx and trachea. iFOMM was used in 3 patients. Functional and esthetic outcomes, short-term and long-term complications were analyzed. The flap was successful in 74 out of 75 patients. Speech was intelligible in almost all patients and majority of patients could take oral feeds without any restrictions. The esthesis of reconstruction was scored high with a mean visual analog scale score of 8.4. The most commonly observed complication was marginal mandibular paresis, which improved with time. Mouth opening was >3 cm in 68/75 patients. Adjuvant radiation was a common factor in patients with <3 cm mouth opening. Flap was sensate by 4 months in majority of patients. The reach, pliability, and esthetics of the flap combined with recoverable morbidity of donor site present in the facial artery-based flap as a good option in the reconstruction of various head and neck subsites. Reduced operative time, lesser complication rates, less financial burden, and simplicity of the procedure make it a cost-effective alternate solution for reconstruction.

Facial Artery Musculomucosal Flap for Nasopharyngeal and Oropharyngeal Reconstruction.

Importance: The facial artery musculomucosal (FAMM) flap is a well vascularized axial flap which has been described for mucosal reconstructions throughout the oral cavity. There are limited data regarding its efficacy in secondary repair of nasopharyngeal stenosis and velopharyngeal insufficiency due previous surgery and scar tissue formation. Objective: This study seeks to demonstrate the efficacy of FAMM flap procedure in patients with nasopharyngeal stenosis and velopharyngeal insufficiency. Design, Setting, and Participants: A retrospective case series included patients treated for nasopharyngeal stenosis or velopharyngeal insufficiency with a FAMM flap at an academic medical center from January 1, 2012 to November 1, 2017. Patients included in the study were those who underwent a FAMM flap procedure by the senior author during the specified time period. Main Outcomes and Measures: Functional outcomes included nasopharyngeal airway patency, nasal regurgitation, and speech quality. Any postoperative complications were recorded, including flap necrosis, infection, flap failure, dehiscence, trismus and need for revision surgery. Results: A total of 6 FAMM flap procedures were performed by the senior author over the study period for the indications of this case series. Three patients had nasopharyngeal stenosis and three had velopharyngeal insufficiency. All had successful, sustained nasopharyngeal airway patency or restored velopharyngeal function. The only postoperative complication noted was trismus at the cheek donor site. There were no patients who suffered flap failure or need for revision surgery of the FAMM flap. Conclusions: The FAMM flap is useful for secondary reconstruction of nasopharyngeal stenosis and velopharyngeal insufficiency due to previous surgery and scarring. This study demonstrates the efficacy and reliability of FAMM flaps for repair of complete/near complete nasopharyngeal stenosis and cases of velopharyngeal insufficiency due to scarring of the pharynx.

Facial Nerve Trauma: Clinical Evaluation and Management Strategies.

The field of facial paralysis requires the reconstructive surgeon to apply a wide spectrum of reconstructive and aesthetic principles, using a comprehensive array of surgical tools, including microsurgery, peripheral nerve surgery, and aesthetic facial surgery on the road to optimize patient outcomes. The distinct deficits created by different anatomical levels of facial nerve injury require a fundamental understanding of facial nerve anatomy. Palsy duration, followed by location and mechanism, will determine mimetic muscle salvageability, by means of either direct repair, grafting, or nerve transfers, whereas longer palsy durations will necessitate introducing a new neuromuscular unit, whether by muscle transfer or free functional muscle transplant. A thorough history, physical examination, and basic understanding of ancillary studies, emphasizing palsy duration, location, and mechanism of injury, are critical in evaluation, prognostication, and treatment strategies in traumatic facial palsy patients. The importance of ancillary and aesthetic procedures cannot be overstated. Although these do not provide motion, they constitute essential tools in the treatment of facial paralysis, providing both protective and improved aesthetic outcomes, yielding the highest impact in final surgeon and patient satisfaction, bringing our patients to smile not only on the outside, but also on the inside.

Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery.

BACKGROUND: The facial nerve and its branches are at risk of injury during dermatologic surgery. Few publications in the dermatologic literature discuss facial nerve injury and management. OBJECTIVE: To review facial nerve injury and management, including static and dynamic repair techniques, and to review outcomes in facial nerve reconstruction. METHODS: Two detailed literature reviews were performed using PubMed. First, articles reporting facial nerve injury and/or management in the dermatologic literature were identified. In addition, articles pertaining to outcomes in facial nerve reconstruction with a minimum of 20 patients were included. RESULTS: Fifty-three articles reporting outcomes in facial nerve reconstruction were identified and consist of retrospective reviews and case series. Most patients achieve improvement in facial symmetry and movement with nerve repair. CONCLUSION: Timing of facial nerve repair is an important consideration in management of facial nerve injury, with earlier repairs achieving better outcomes. Facial nerve repair does not result in normal facial movement, and improvements may require a year or more to be realized. Many options exist for facial nerve reconstruction, and patients with long-standing facial nerve injuries may still benefit from treatment.

Upper blepharoplasty revision technique: Correction of the high eyelid fold using the pretarsal orbicularis oculi flap.

PURPOSE: With the growing popularity of upper lid blepharoplasty, there have been increasing reports of unsatisfactory outcomes that have necessitated a revision surgery. This study aimed to evaluate aesthetic outcomes of surgical correction of the high eyelid fold using a pretarsal orbicularis oculi flap and to highlight the key practice points of this surgical procedure in secondary blepharoplasty. METHODS: A retrospective study of 31 consecutive Chinese patients who underwent revision surgeries between January 2013 and December 2015 was undertaken through a review of medical records. All these patients underwent surgical correction of high eyelid folds using a pretarsal orbicularis oculi flap, with postoperative follow-up ranging from 6 months to 4 years. Postoperative outcomes were reviewed, evaluated, and analyzed. RESULTS: In this study of 31 women who underwent secondary revision procedure of the high eyelid fold using a pretarsal orbicularis oculi muscle flap, mean follow-up time was 8.2 (range 6-48) months. All flaps survived without significant complications. There was no reported incidence of hematoma or infection in early postoperative complications. Clinical effectiveness was satisfactory in most of the patients who underwent fold repair (26/31, 83.9%). However, five patients (16.1%) expressed dissatisfaction with postoperative outcomes; of them, four patients (12.9%) had mild asymmetry, whereas surgical revision was required in only one patient (3.2%). CONCLUSION: Secondary blepharoplasty to correct the high eyelid fold is a challenging procedure for plastic surgeons. Use of the pretarsal orbicularis oculi muscle flap for correction of the high eyelid fold is safe and effective, with better biomechanics and a satisfying aesthetic outcome. This provides a novel treatment option in limited secondary revision techniques.

The Arterialized Facial Artery Musculo-Mucosal Island Flap for Post-Oncological Tongue Reconstruction.

BACKGROUND: In 1992, Pribaz described the facial artery musculomucosal flap (FAMM), an axial musculomucosal flap based on the facial artery. The FAMM flap, a modification of the nasolabial and buccal mucosal flaps, is widely used in the reconstruction of defects in the oral cavity. Many modifications of this flap have been described in the literature. Here we aimed to explore the use of an arterialized tunnelized FAMM island flap (a-FAMMIF) for the reconstruction tongue defects after tumor resection. METHOD: From January 2015 to December 2016, five cases of tongue cancer were selected for the use of arterialized FAMMIF flap to reconstruct defects after tumor resection. RESULTS: Reconstruction was successful in all cases, except one case of total flap necrosis; partial necrosis of the flap occurred in two patients, which were solved with medications. CONCLUSION: The authors consider the a-FAMMIF an unreliable flap in the reconstruction of tongue defects.The authors recommend avoiding tunneling and island modification when the vein is not included in the pedicle.

Unilateral Buccinator Flap for Lengthening of Short Palate.

BACKGROUND: Velopharyngeal insufficiency is one of the most frequent complications after cleft palate repair. PURPOSE: To evaluate the results and complications of unilateral Buccinator flap (BMF) in velopharyngeal insufficiency. MATERIALS AND METHODS: During 4 years the authors performed unilateral BMF in all short palates. Age, sex, demographic data, length of palate, cause of short palate, nasopharyngoscopy and videofluroscopy results, hyper nasality, nasal escape, nasal emission, nasal fluid leak, speech evaluation and results, outcome and complications of the treatment were surveyed before surgery and in 1, 3, 6 months after treatment. RESULTS: The authors had 43 patients, 29 below 8 years old and 14 adults. Velopharyngeal gap was between 10 and 27 mm, mean 21 mm. Buccinator flap were measuring 15 to 19 mm in width and 32 to 56 mm in length. The operation time was 80 to 100 minutes, mean 86 minutes.Nasal emission, nasal escape, and nasal leak were treated in all patients.Hyper nasality was completely improved in all of the patients below 8 years old (29 patients) and in 10 patients of the adults (totally 39 patients, 90.6%). And it was improved significantly in other 4 patients (9.4%). The speech evaluation reported between 70% and 86% improvements.The lengthening of the palate was between 12 and 19 mm, mean 17 mm.The satisfaction of the patients was as 0% poor, 2.3% fair, 72.1% good, and 25.6% excellent. CONCLUSION: Unilateral BMF is reliable, promising, and safe flap for lengthening of short palate and it can lengthen the palate up to 19 mm. The time of surgery is very short compared with other methods. It is an anatomical treatment versus pharyngeal flap which is not an anatomical one. Speech improvement will achieve in 70% to 86% patients.

Modified Composite-Flap Facelift Combined With Finger-Assisted Malar Elevation (FAME): A Cadaver Study.

BACKGROUND: Inadequate release of retaining ligaments during facelift surgery may lead to an unnatural appearance. However, most facelift surgeons are hesitant in transecting these ligaments to avoid possible injury to facial subbranches. OBJECTIVES: In the authors' surgical practice for modified composite flap rhytidectomy, the authors employed the finger-assisted malar elevation (FAME) technique in order to enable safe release of the zygomatic cutaneous ligaments through the prezygomatic space under direct vision. The aim was to evaluate the anatomical basis and safety measures of this technique through a cadaveric dissection study. METHODS: Modified composite-flap facelift with the FAME technique was carried out in 22 fresh cadaver hemi-faces. All facial nerve subbranches were dissected thoroughly to assess for any evidence of injury during facelift, and to evaluate the safety of the operation. The relations among the facial nerve, zygomatic cutaneous and masseteric ligaments, orbicularis oculi muscle, and malar fat pad were investigated. RESULTS: Finger dissection of the prezygomatic space allows safe release of the zygomatic cutaneous ligaments as well as adequate entry to a proper surgical plane above the zygomatici muscles under direct vision, while leaving the malar fat pad and overlying structures attached to the skin without the need of a transblepharoplasty approach. CONCLUSIONS: This study by the authors shows that a modified composite-flap facelift with FAME technique is a safe procedure that allows adequate and effective repositioning of an en-bloc composite flap that produces balanced and harmonious rejuvenation of the midface and lower face without the need of a separate midface lift.

Decreasing Revision Surgery in FAMM Flap Reconstruction of the Oral Cavity: Traditional Versus Modified Harvesting Technique.

OBJECTIVE: To compare the surgical and functional outcomes between two harvesting techniques for the inferiorly based facial artery musculomucosal (FAMM) flap for oral cavity and oropharynx reconstructions. METHODS: Multicenter retrospective chart review. RESULTS: We reviewed 55 cases of FAMM flap, including 29 traditional cases and 26 performed using the modified harvesting method. The overall rate of surgical re-intervention in the traditional group was 31% (n = 9 of 29) and 15% (n = 4 of 26) in the modified group (P = 0.196). The specific re-intervention rate for pedicle sectioning was 27% (n = 8 of 29) in the traditional group versus 0% (n = 0 of 26) in the modified group. The overall rate of complications was 21%. Nine out of 10 dentate patients in the traditional group and four out of five in the modified group needed tooth extraction. There was no difference between the two groups in terms of tracheostomy duration (P = 0.338) and time to first oral intake (P = 0.629). Speech and feeding outcomes were similar among groups (P = 0.922; P = 0.700, respectively). Dental rehabilitation was achieved in 67% and 78% of patients in the traditional and modified groups, respectively. CONCLUSION: The FAMM flap offers a low morbidity approach to reconstruct the oral cavity. The modified approach to harvesting the flap is a safe and effective technique, with similar functional results and equally low morbidity profile as the traditional technique. It has the added advantage of lower rates of secondary surgical interventions. LEVEL OF EVIDENCE: 4. Laryngoscope, 1802-1805, 2018.

Fascial Graft Repair of Wide Bilateral Cleft Lip Deformity.

Wide bilateral cleft lip deformity reconstruction represents a special difficulty as it affects the lip, nose, and maxillary segments making single-stage reconstruction sometimes unobtainable. Many surgical and nonsurgical techniques have been prescribed to facilitate the definitive repair. Although some of these techniques proved to be useful, they have their inherent limitations and add another treatment step with all its possible complications and costs. The authors present a new method to address muscle layer repair in 1-stage procedure. It entails using fascial graft obtained from the temporalis muscle fascia or fascia lata, to reconstruct orbicularis oris lip muscle. Seven patients of wide bilateral cleft lip deformity (mean 17 mm) with a mean age of 4.4 months were subjected to single-stage lip reconstruction. After measuring the defect between both lateral muscle segments in front of the premaxilla intraoperatively ensuring that direct muscle repair could not be obtained, a fascial graft was harvested and sutured to both muscle edges. The authors found that, regardless the defect size or premaxilla protrusion, all wide clefts could be reconstructed satisfactorily in 1 stage procedure. No serious postoperative complications have been encountered in the lip or donor areas. Early follow-up reporting of the patients revealed stable repair. However more follow-up is still needed to assess late sequelae. In conclusion, fascial graft muscle repair of wide bilateral cleft lip deformity enables early 1-stage lip reconstruction without tension. The added donor morbidity is minimal and well tolerated.

Superiorly based facial artery musculomucosal flap: A versatile pedicled flap.

BACKGROUND: The superiorly based facial artery musculomucosal (FAMM) flap is pedicled on the angular artery. This flap offers a well-vascularized mucosal surface allowing closure of medium size defects, most frequently within the oral cavity and intranasal region. METHODS: We describe a superiorly based harvest of the FAMM flap, which may be used for closure of multiple head and neck surgical defects. An operative technique video is provided, which can be viewed online. RESULTS: Our results demonstrate a fast and relatively straightforward harvest technique of the FAMM flap. This intraoral flap is a useful reconstructive tool, which also has the advantage to leave no visible external scars. CONCLUSION: The superiorly pedicled FAMM flap is a versatile and effective technique that may be integrated in the algorithm for reconstruction of head and neck defects.

A Systematic Review of Lower Lip Anatomy, Mechanics of Local Flaps, and Special Considerations for Lower Lip Reconstruction.

Reconstruction of defects of the lower lip can be very challenging. The aim of this review is to analyze the unique characteristics of lower lip anatomy and provide a systematic approach for lower lip reconstruction. A review of current literature was performed using the PubMed database. Articles analyzing the anatomic and histologic characteristics of the lower lip, mechanics of local faps, and different lower lip reconistruction techniques were included. Articles focused on lower lip reconstruction with free faps were excluded. The orbicularis oris has been described as the main supportive mechanism, however, a number of other structures have been shown to provide mechanical support to the lower lip, including septations of connective tissue extending from the epithelium to the orbicularis oris, a fbroelastic meshwork located in the mentolabial sulcus, and subdermal muscular fibers with dermal terminations in the area of the modiolus. Depending on the location, size, and depth of the wound, a number of reconstruction options are available. Preservation of the competency of orbicularis oris, relation-ship of the modiolus with associated muscles, and sensation, are critical components of functional reconstruction. Primary closure and local faps are assessed for these 3 components and analysis is provided. In conclusion, knowledge of the static and dynamic structural support of the lower lip, as well as the characteristics of different reconstructive options, is imperative for optimal functional and aesthetic outcomes.

Autologous Tissue Graft in Revision Medial Epicanthoplasty Using Subciliary Fat and Orbicularis Oculi Muscle.

The medial epicanthal fold is one of the racial anatomic characteristics of Asians. As medial epicanthoplasty has become one of the most common cosmetic surgeries among Asians, the need for revision of overcorrected medial epicanthus also increased. In revision medial epicanthoplasty, an autologous tissue graft to the subcutaneous plane is used to reduce postoperative scar. Medial epicanthoplasty, using V-Y advancement and rotation flap, was performed in 93 patients (revision medial epicanthoplasty with autologous tissue graft, 60 patients; revision medial epicanthoplasty only, 33 patients). A V-Y and rotation flap was designed to cover the overexposed lacrimal lake. A small amount of fat tissue and orbicularis oculi muscle were harvested from the upper eyelid through the double-fold line and grafted to the subcutaneous space of the medial epicanthal area. We evaluated the patients' satisfaction with the overall outcome and scar. The mean intercanthal distance increased from 32.3 mm before surgery to 34.6 mm after surgery. Satisfaction with the scar and overall outcome was higher in the patient group who underwent medial epicanthoplasty with autologous tissue graft. No complication was observed in the autologous tissue graft group, whereas 1 patient who underwent medial epicanthoplasty without autologous tissue graft showed recurrence of the medial epicanthal fold, 5 months after surgery. Medial epicanthoplasty with autologous tissue graft is a simple and reliable method to repair the overcorrected medial epicanthus that can efficiently increase the intercanthal distance and prevent scar contracture.

Single-Stage Reconstruction of Eyebrow Defect Using a V-Y Advancement Pedicle Flap Based on the Orbicularis Oculi Muscle.

Eyebrows play an important role in face expression and facial mimics by virtue of muscle contraction. Defects or deformity of the eyebrows result in abnormal facial expressions, and may lead to aesthetic issues for patients. The objective of this study is to report the case of a patient, with a congenital skin pigmented nevus at the right side of the eyebrow treated with direct surgical resection and followed by immediate reconstruction of the eyebrow with a V-Y advancement pedicle flap based on the orbicularis oculi muscle.

Bilateral buccinator myomucosal flap outcomes in nonsyndromic patients with repaired cleft palate and velopharyngeal insufficiency.

BACKGROUND: The purpose of this study was to assess speech outcomes and complication rate in nonsyndromic repaired cleft palate patients undergoing bilateral buccinator myomucosal flaps for velopharyngeal insufficiency management. METHODS: A prospective study of consecutive repaired cleft palate patients with velopharyngeal insufficiency who underwent bilateral buccinator myomucosal flaps was conducted. Three experienced evaluators performed a blinded perceptual speech evaluation (hypernasality, audible nasal emission, and intraoral pressure). Successful speech outcome was defined as normal or borderline sufficient velopharyngeal function at 15 months postoperatively. Obstructive sleep apnea screening tools were applied preoperatively and postoperatively. Complication rate was also collected. RESULTS: Fifty-three patients were included. There were 11 (21%) surgical complications, with no complete flap loss, snoring, sleep disturbance, and/or mouth breathing. All patients presented low pre- and postoperative risk for obstructive sleep apnea. At 15 months postoperatively, hypernasality (0.4 ± 0.6), audible nasal emissions (0.2 ± 0.4), and intraoral pressure (0.1 ± 0.3) were significantly (all p < 0.05) lower than preoperative measurements (hypernasality: 2.7 ± 0.5; audible nasal emissions: 2.2 ± 0.8; and intraoral pressure: 0.9 ± 0.3). Forty-five (85%) patients presented successful speech outcome. CONCLUSION: The bilateral buccinator myomucosal flap is an effective and safe surgical strategy for the management of persistent velopharyngeal insufficiency.